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Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/doc')
52 files changed, 94536 insertions, 0 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/doc/arm-neon-intrinsics.texi b/gcc-4.2.1-5666.3/gcc/doc/arm-neon-intrinsics.texi new file mode 100644 index 000000000..58303784f --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/arm-neon-intrinsics.texi @@ -0,0 +1,11294 @@ +@c APPLE LOCAL file ARM NEON Intrinsics. Merge from Codesourcery. */ +@c Copyright (C) 2006 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c This file is generated automatically using gcc/config/arm/neon-docgen.ml +@c Please do not edit manually. +@subsubsection Addition + +@itemize @bullet +@item uint32x2_t vadd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vadd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vadd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vadd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vadd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vadd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vadd_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vadd_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vadd_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vadd.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vaddq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vaddq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vaddq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vaddq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vaddq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vaddq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vaddq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vaddq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vadd.i64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vaddq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vadd.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vaddl_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vaddl_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vaddl_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vaddl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vaddl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vaddl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddl.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vaddw_u32 (uint64x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.u32 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vaddw_u16 (uint32x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.u16 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vaddw_u8 (uint16x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.u8 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vaddw_s32 (int64x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.s32 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vaddw_s16 (int32x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.s16 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vaddw_s8 (int16x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddw.s8 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vhadd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vhadd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vhadd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vhadd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vhadd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vhadd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vhaddq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vhaddq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vhaddq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vhaddq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vhaddq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vhaddq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vhadd.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrhadd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrhadd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrhadd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrhadd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrhadd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrhadd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrhaddq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrhaddq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrhaddq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vrhaddq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrhaddq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrhaddq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrhadd.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqadd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqadd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqadd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqadd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqadd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqadd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqadd_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vqadd_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqaddq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqaddq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqaddq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqaddq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqaddq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqaddq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqaddq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqaddq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqadd.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vaddhn_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vaddhn_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vaddhn_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vaddhn_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vaddhn_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vaddhn_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vaddhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vraddhn_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vraddhn_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vraddhn_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vraddhn_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vraddhn_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vraddhn_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vraddhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Multiplication + +@itemize @bullet +@item uint32x2_t vmul_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmul_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmul_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmul_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmul_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmul_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmul_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vmul_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmul.p8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmulq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmulq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmulq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmulq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmulq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmulq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vmulq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vmulq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.p8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqdmulh_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqdmulh_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmulhq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqdmulhq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqrdmulh_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqrdmulh_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqrdmulhq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqrdmulhq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmull_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmull.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmull_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmull.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmull_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmull.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vmull_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmull.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmull_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmull.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmull_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmull.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vmull_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmull.p8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmull_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmull_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Multiply-accumulate + +@itemize @bullet +@item uint32x2_t vmla_u32 (uint32x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmla_u16 (uint16x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmla_u8 (uint8x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmla_s32 (int32x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmla_s16 (int16x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmla_s8 (int8x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmla_f32 (float32x2_t, float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlaq_u32 (uint32x4_t, uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlaq_u16 (uint16x8_t, uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmlaq_u8 (uint8x16_t, uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlaq_s32 (int32x4_t, int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlaq_s16 (int16x8_t, int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmlaq_s8 (int8x16_t, int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlaq_f32 (float32x4_t, float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlal_u32 (uint64x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlal_u16 (uint32x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlal_u8 (uint16x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlal_s32 (int64x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlal_s16 (int32x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlal_s8 (int16x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlal_s32 (int64x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlal_s16 (int32x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Multiply-subtract + +@itemize @bullet +@item uint32x2_t vmls_u32 (uint32x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmls_u16 (uint16x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmls_u8 (uint8x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmls_s32 (int32x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmls_s16 (int16x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmls_s8 (int8x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmls_f32 (float32x2_t, float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsq_u32 (uint32x4_t, uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlsq_u16 (uint16x8_t, uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmlsq_u8 (uint8x16_t, uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsq_s32 (int32x4_t, int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlsq_s16 (int16x8_t, int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmlsq_s8 (int8x16_t, int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlsq_f32 (float32x4_t, float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlsl_u32 (uint64x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsl_u16 (uint32x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlsl_u8 (uint16x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlsl_s32 (int64x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsl_s16 (int32x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlsl_s8 (int16x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlsl_s32 (int64x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlsl_s16 (int32x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Subtraction + +@itemize @bullet +@item uint32x2_t vsub_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vsub_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vsub_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vsub_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vsub_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vsub_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vsub_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vsub_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vsub_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsub.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsubq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsubq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vsubq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsubq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsubq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vsubq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsubq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsubq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vsub.i64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vsubq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vsub.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsubl_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsubl_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsubl_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsubl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsubl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsubl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubl.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsubw_u32 (uint64x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.u32 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsubw_u16 (uint32x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.u16 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsubw_u8 (uint16x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.u8 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsubw_s32 (int64x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.s32 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsubw_s16 (int32x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.s16 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsubw_s8 (int16x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubw.s8 @var{q0}, @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vhsub_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vhsub_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vhsub_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vhsub_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vhsub_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vhsub_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vhsubq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vhsubq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vhsubq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vhsubq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vhsubq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vhsubq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vhsub.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqsub_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqsub_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqsub_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqsub_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqsub_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqsub_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqsub_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vqsub_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqsubq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqsubq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqsubq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqsubq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqsubq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqsubq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqsubq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqsubq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqsub.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vsubhn_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vsubhn_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vsubhn_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vsubhn_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vsubhn_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vsubhn_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vsubhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrsubhn_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrsubhn_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrsubhn_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrsubhn_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i64 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrsubhn_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i32 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrsubhn_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrsubhn.i16 @var{d0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (equal-to) + +@itemize @bullet +@item uint32x2_t vceq_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vceq_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vceq_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vceq_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vceq_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vceq_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vceq_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vceq.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vceq_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vceqq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vceqq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vceqq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vceqq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vceqq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vceqq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vceqq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vceq.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vceqq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vceq.i8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (greater-than-or-equal-to) + +@itemize @bullet +@item uint32x2_t vcge_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcge_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcge_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcge_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcge_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcge_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcge_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgeq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcgeq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcgeq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgeq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcgeq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcgeq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgeq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (less-than-or-equal-to) + +@itemize @bullet +@item uint32x2_t vcle_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcle_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcle_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcle_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcle_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcle_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcle_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcge.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcleq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcleq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcleq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcge.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcleq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcleq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcleq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcge.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcleq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcge.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (greater-than) + +@itemize @bullet +@item uint32x2_t vcgt_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcgt_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcgt_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcgt_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vcgt_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vcgt_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcgt_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgtq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcgtq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcgtq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgtq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcgtq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcgtq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcgtq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (less-than) + +@itemize @bullet +@item uint32x2_t vclt_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vclt_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vclt_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vclt_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vclt_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vclt_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vclt_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcltq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcltq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcltq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcltq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vcltq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcltq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcltq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcgt.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (absolute greater-than-or-equal-to) + +@itemize @bullet +@item uint32x2_t vcage_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vacge.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcageq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vacge.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (absolute less-than-or-equal-to) + +@itemize @bullet +@item uint32x2_t vcale_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vacge.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcaleq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vacge.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (absolute greater-than) + +@itemize @bullet +@item uint32x2_t vcagt_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vacgt.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcagtq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vacgt.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Comparison (absolute less-than) + +@itemize @bullet +@item uint32x2_t vcalt_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vacgt.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcaltq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vacgt.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Test bits + +@itemize @bullet +@item uint32x2_t vtst_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vtst.32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vtst_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vtst.16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtst_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vtst_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vtst.32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vtst_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vtst.16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtst_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtst_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vtstq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vtst.32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vtstq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vtst.16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vtstq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vtstq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vtst.32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vtstq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vtst.16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vtstq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vtstq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtst.8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Absolute difference + +@itemize @bullet +@item uint32x2_t vabd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vabd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vabd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vabd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vabd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vabd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vabd_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabd.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vabdq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vabdq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vabdq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vabd.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vabdq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vabdq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vabdq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vabd.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vabdq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vabd.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vabdl_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vabdl_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vabdl_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vabdl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vabdl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vabdl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabdl.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Absolute difference and accumulate + +@itemize @bullet +@item uint32x2_t vaba_u32 (uint32x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vaba_u16 (uint16x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vaba_u8 (uint8x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vaba_s32 (int32x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vaba_s16 (int16x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vaba_s8 (int8x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vabaq_u32 (uint32x4_t, uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vabaq_u16 (uint16x8_t, uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vabaq_u8 (uint8x16_t, uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vaba.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vabaq_s32 (int32x4_t, int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vabaq_s16 (int16x8_t, int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vabaq_s8 (int8x16_t, int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vaba.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vabal_u32 (uint64x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabal.u32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vabal_u16 (uint32x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabal.u16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vabal_u8 (uint16x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabal.u8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vabal_s32 (int64x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabal.s32 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vabal_s16 (int32x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabal.s16 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vabal_s8 (int16x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabal.s8 @var{q0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Maximum + +@itemize @bullet +@item uint32x2_t vmax_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmax_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmax_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmax_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmax_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmax_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmax_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmax.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmaxq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmaxq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmaxq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmax.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmaxq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmaxq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmaxq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmax.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vmaxq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmax.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Minimum + +@itemize @bullet +@item uint32x2_t vmin_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmin_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmin_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmin_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmin_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmin_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmin_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmin.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vminq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vminq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vminq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmin.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vminq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vminq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vminq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmin.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vminq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmin.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Pairwise add + +@itemize @bullet +@item uint32x2_t vpadd_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vpadd_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vpadd_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vpadd_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vpadd_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vpadd_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.i8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vpadd_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpadd.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vpaddl_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vpaddl_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vpaddl_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vpaddl_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vpaddl_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vpaddl_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vpaddlq_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vpaddlq_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vpaddlq_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.u8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vpaddlq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vpaddlq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vpaddlq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vpaddl.s8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Pairwise add, single_opcode widen and accumulate + +@itemize @bullet +@item uint64x1_t vpadal_u32 (uint64x1_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vpadal_u16 (uint32x2_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vpadal_u8 (uint16x4_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vpadal_s32 (int64x1_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vpadal_s16 (int32x2_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vpadal_s8 (int16x4_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vpadalq_u32 (uint64x2_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vpadalq_u16 (uint32x4_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vpadalq_u8 (uint16x8_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.u8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vpadalq_s32 (int64x2_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vpadalq_s16 (int32x4_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vpadalq_s8 (int16x8_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vpadal.s8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Folding maximum + +@itemize @bullet +@item uint32x2_t vpmax_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vpmax_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vpmax_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vpmax_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vpmax_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vpmax_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vpmax_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmax.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Folding minimum + +@itemize @bullet +@item uint32x2_t vpmin_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vpmin_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vpmin_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vpmin_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vpmin_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vpmin_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vpmin_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vpmin.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Reciprocal step + +@itemize @bullet +@item float32x2_t vrecps_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrecps.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vrecpsq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrecps.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vrsqrts_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrts.f32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vrsqrtsq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrts.f32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Vector shift left + +@itemize @bullet +@item uint32x2_t vshl_u32 (uint32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vshl_u16 (uint16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vshl_u8 (uint8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vshl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vshl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vshl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vshl_u64 (uint64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vshl_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vshlq_u32 (uint32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vshlq_u16 (uint16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vshlq_u8 (uint8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vshlq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vshlq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vshlq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vshlq_u64 (uint64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vshl.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vshlq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vshl.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrshl_u32 (uint32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrshl_u16 (uint16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrshl_u8 (uint8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrshl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrshl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrshl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vrshl_u64 (uint64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vrshl_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrshlq_u32 (uint32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrshlq_u16 (uint16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrshlq_u8 (uint8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vrshlq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrshlq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrshlq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vrshlq_u64 (uint64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vrshlq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vrshl.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqshl_u32 (uint32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqshl_u16 (uint16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqshl_u8 (uint8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqshl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqshl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqshl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqshl_u64 (uint64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vqshl_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqshlq_u32 (uint32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqshlq_u16 (uint16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqshlq_u8 (uint8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqshlq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqshlq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqshlq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqshlq_u64 (uint64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqshlq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqshl.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqrshl_u32 (uint32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqrshl_u16 (uint16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqrshl_u8 (uint8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqrshl_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s32 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqrshl_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s16 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqrshl_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s8 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqrshl_u64 (uint64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vqrshl_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s64 @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqrshlq_u32 (uint32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqrshlq_u16 (uint16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqrshlq_u8 (uint8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqrshlq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s32 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqrshlq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s16 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqrshlq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s8 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqrshlq_u64 (uint64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.u64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqrshlq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqrshl.s64 @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Vector shift left by constant + +@itemize @bullet +@item uint32x2_t vshl_n_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vshl_n_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vshl_n_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vshl_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vshl_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vshl_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vshl_n_u64 (uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vshl_n_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vshlq_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vshlq_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vshlq_n_u8 (uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vshlq_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vshlq_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vshlq_n_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vshlq_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vshlq_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshl.i64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqshl_n_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqshl_n_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqshl_n_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqshl_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqshl_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqshl_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqshl_n_u64 (uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vqshl_n_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqshlq_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqshlq_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqshlq_n_u8 (uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqshlq_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqshlq_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqshlq_n_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqshlq_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.u64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vqshlq_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshl.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vqshlu_n_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqshlu_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqshlu_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqshlu_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vqshluq_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vqshluq_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vqshluq_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vqshluq_n_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshlu.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vshll_n_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.u32 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vshll_n_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.u16 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vshll_n_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.u8 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vshll_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.s32 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vshll_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.s16 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vshll_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshll.s8 @var{q0}, @var{d0}, #@var{0}} +@end itemize + + + + +@subsubsection Vector shift right by constant + +@itemize @bullet +@item uint32x2_t vshr_n_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vshr_n_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vshr_n_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vshr_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vshr_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vshr_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vshr_n_u64 (uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vshr_n_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vshrq_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vshrq_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vshrq_n_u8 (uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vshrq_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vshrq_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vshrq_n_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vshrq_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.u64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vshrq_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshr.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrshr_n_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrshr_n_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrshr_n_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrshr_n_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrshr_n_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrshr_n_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vrshr_n_u64 (uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vrshr_n_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrshrq_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrshrq_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrshrq_n_u8 (uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vrshrq_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrshrq_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrshrq_n_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vrshrq_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.u64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vrshrq_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshr.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vshrn_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vshrn_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vshrn_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vshrn_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vshrn_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vshrn_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vshrn.i16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrshrn_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrshrn_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrshrn_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrshrn_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrshrn_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrshrn_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrshrn.i16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqshrn_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.u64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqshrn_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.u32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqshrn_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.u16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqshrn_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.s64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqshrn_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.s32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqshrn_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrn.s16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqrshrn_n_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.u64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqrshrn_n_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.u32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqrshrn_n_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.u16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqrshrn_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.s64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqrshrn_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.s32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqrshrn_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrn.s16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqshrun_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrun.s64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqshrun_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrun.s32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqshrun_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqshrun.s16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqrshrun_n_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrun.s64 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqrshrun_n_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrun.s32 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqrshrun_n_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrshrun.s16 @var{d0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Vector shift right by constant and accumulate + +@itemize @bullet +@item uint32x2_t vsra_n_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vsra_n_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vsra_n_u8 (uint8x8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vsra_n_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vsra_n_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vsra_n_s8 (int8x8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vsra_n_u64 (uint64x1_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vsra_n_s64 (int64x1_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsraq_n_u32 (uint32x4_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsraq_n_u16 (uint16x8_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vsraq_n_u8 (uint8x16_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsraq_n_s32 (int32x4_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsraq_n_s16 (int16x8_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vsraq_n_s8 (int8x16_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsraq_n_u64 (uint64x2_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.u64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsraq_n_s64 (int64x2_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsra.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrsra_n_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrsra_n_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrsra_n_u8 (uint8x8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrsra_n_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrsra_n_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrsra_n_s8 (int8x8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vrsra_n_u64 (uint64x1_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vrsra_n_s64 (int64x1_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrsraq_n_u32 (uint32x4_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrsraq_n_u16 (uint16x8_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrsraq_n_u8 (uint8x16_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vrsraq_n_s32 (int32x4_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrsraq_n_s16 (int16x8_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrsraq_n_s8 (int8x16_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vrsraq_n_u64 (uint64x2_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.u64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vrsraq_n_s64 (int64x2_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vrsra.s64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Vector shift right and insert + +@itemize @bullet +@item uint32x2_t vsri_n_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vsri_n_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vsri_n_u8 (uint8x8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vsri_n_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vsri_n_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vsri_n_s8 (int8x8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vsri_n_u64 (uint64x1_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vsri_n_s64 (int64x1_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vsri_n_p16 (poly16x4_t, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vsri_n_p8 (poly8x8_t, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsriq_n_u32 (uint32x4_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsriq_n_u16 (uint16x8_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vsriq_n_u8 (uint8x16_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsriq_n_s32 (int32x4_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsriq_n_s16 (int16x8_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vsriq_n_s8 (int8x16_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsriq_n_u64 (uint64x2_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsriq_n_s64 (int64x2_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vsriq_n_p16 (poly16x8_t, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vsriq_n_p8 (poly8x16_t, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsri.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Vector shift left and insert + +@itemize @bullet +@item uint32x2_t vsli_n_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vsli_n_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vsli_n_u8 (uint8x8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vsli_n_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vsli_n_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vsli_n_s8 (int8x8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vsli_n_u64 (uint64x1_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vsli_n_s64 (int64x1_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.64 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vsli_n_p16 (poly16x4_t, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vsli_n_p8 (poly8x8_t, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsliq_n_u32 (uint32x4_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsliq_n_u16 (uint16x8_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vsliq_n_u8 (uint8x16_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsliq_n_s32 (int32x4_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsliq_n_s16 (int16x8_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vsliq_n_s8 (int8x16_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsliq_n_u64 (uint64x2_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsliq_n_s64 (int64x2_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.64 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vsliq_n_p16 (poly16x8_t, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.16 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vsliq_n_p8 (poly8x16_t, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vsli.8 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Absolute value + +@itemize @bullet +@item float32x2_t vabs_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabs.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vabs_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vabs_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vabs_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vabsq_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vabs.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vabsq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vabsq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vabsq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vabs.s8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqabs_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqabs_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqabs_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqabsq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqabsq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqabsq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqabs.s8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Negation + +@itemize @bullet +@item float32x2_t vneg_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vneg.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vneg_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vneg_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vneg_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vnegq_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vneg.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vnegq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vnegq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vnegq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vneg.s8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqneg_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqneg_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqneg_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vqnegq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vqnegq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vqnegq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vqneg.s8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Bitwise not + +@itemize @bullet +@item uint32x2_t vmvn_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmvn_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmvn_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmvn_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmvn_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmvn_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vmvn_p8 (poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmvnq_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmvnq_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmvnq_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmvnq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmvnq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmvnq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vmvnq_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmvn @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Count leading sign bits + +@itemize @bullet +@item int32x2_t vcls_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vcls_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vcls_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vclsq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vclsq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vclsq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcls.s8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Count leading zeros + +@itemize @bullet +@item uint32x2_t vclz_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vclz_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vclz_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vclz_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vclz_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vclz_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vclzq_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vclzq_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vclzq_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vclzq_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vclzq_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vclzq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vclz.i8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Count number of set bits + +@itemize @bullet +@item uint8x8_t vcnt_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vcnt_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vcnt_p8 (poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vcntq_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vcntq_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vcntq_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vcnt.8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Reciprocal estimate + +@itemize @bullet +@item float32x2_t vrecpe_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrecpe.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrecpe_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrecpe.u32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vrecpeq_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrecpe.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrecpeq_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrecpe.u32 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Reciprocal square-root estimate + +@itemize @bullet +@item float32x2_t vrsqrte_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrte.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vrsqrte_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrte.u32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vrsqrteq_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrte.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrsqrteq_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrsqrte.u32 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Get lanes from a vector + +@itemize @bullet +@item uint32_t vget_lane_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16_t vget_lane_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint8_t vget_lane_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32_t vget_lane_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16_t vget_lane_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int8_t vget_lane_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32_t vget_lane_f32 (float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.f32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly16_t vget_lane_p16 (poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly8_t vget_lane_p8 (poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64_t vget_lane_u64 (uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{r0}, @var{r0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64_t vget_lane_s64 (int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{r0}, @var{r0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32_t vgetq_lane_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16_t vgetq_lane_u16 (uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint8_t vgetq_lane_u8 (uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32_t vgetq_lane_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16_t vgetq_lane_s16 (int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int8_t vgetq_lane_s8 (int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.s8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32_t vgetq_lane_f32 (float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.f32 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly16_t vgetq_lane_p16 (poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u16 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly8_t vgetq_lane_p8 (poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.u8 @var{r0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64_t vgetq_lane_u64 (uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{r0}, @var{r0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64_t vgetq_lane_s64 (int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{r0}, @var{r0}, @var{d0}} +@end itemize + + + + +@subsubsection Set lanes in a vector + +@itemize @bullet +@item uint32x2_t vset_lane_u32 (uint32_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vset_lane_u16 (uint16_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vset_lane_u8 (uint8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vset_lane_s32 (int32_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vset_lane_s16 (int16_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vset_lane_s8 (int8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vset_lane_f32 (float32_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vset_lane_p16 (poly16_t, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vset_lane_p8 (poly8_t, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vset_lane_u64 (uint64_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vset_lane_s64 (int64_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vsetq_lane_u32 (uint32_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vsetq_lane_u16 (uint16_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vsetq_lane_u8 (uint8_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vsetq_lane_s32 (int32_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vsetq_lane_s16 (int16_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vsetq_lane_s8 (int8_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vsetq_lane_f32 (float32_t, float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.32 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vsetq_lane_p16 (poly16_t, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.16 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vsetq_lane_p8 (poly8_t, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov.8 @var{d0}[@var{0}], @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vsetq_lane_u64 (uint64_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vsetq_lane_s64 (int64_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + + + +@subsubsection Create vector from literal bit pattern + +@itemize @bullet +@item uint32x2_t vcreate_u32 (uint64_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vcreate_u16 (uint64_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vcreate_u8 (uint64_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vcreate_s32 (uint64_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vcreate_s16 (uint64_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vcreate_s8 (uint64_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vcreate_u64 (uint64_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vcreate_s64 (uint64_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vcreate_f32 (uint64_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vcreate_p16 (uint64_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vcreate_p8 (uint64_t) +@end itemize + + + + +@subsubsection Set all lanes to the same value + +@itemize @bullet +@item uint32x2_t vdup_n_u32 (uint32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vdup_n_u16 (uint16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vdup_n_u8 (uint8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vdup_n_s32 (int32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vdup_n_s16 (int16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vdup_n_s8 (int8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vdup_n_f32 (float32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vdup_n_p16 (poly16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vdup_n_p8 (poly8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vdup_n_u64 (uint64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vdup_n_s64 (int64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vdupq_n_u32 (uint32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vdupq_n_u16 (uint16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vdupq_n_u8 (uint8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vdupq_n_s32 (int32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vdupq_n_s16 (int16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vdupq_n_s8 (int8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vdupq_n_f32 (float32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vdupq_n_p16 (poly16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vdupq_n_p8 (poly8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vdupq_n_u64 (uint64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vdupq_n_s64 (int64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmov_n_u32 (uint32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmov_n_u16 (uint16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmov_n_u8 (uint8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmov_n_s32 (int32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmov_n_s16 (int16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmov_n_s8 (int8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vmov_n_f32 (float32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vmov_n_p16 (poly16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vmov_n_p8 (poly8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vmov_n_u64 (uint64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vmov_n_s64 (int64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmovq_n_u32 (uint32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmovq_n_u16 (uint16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vmovq_n_u8 (uint8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmovq_n_s32 (int32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmovq_n_s16 (int16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vmovq_n_s8 (int8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vmovq_n_f32 (float32_t) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vmovq_n_p16 (poly16_t) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vmovq_n_p8 (poly8_t) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmovq_n_u64 (uint64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vmovq_n_s64 (int64_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{r0}, @var{r0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vdup_lane_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vdup_lane_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint8x8_t vdup_lane_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vdup_lane_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vdup_lane_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int8x8_t vdup_lane_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x2_t vdup_lane_f32 (float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly16x4_t vdup_lane_p16 (poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly8x8_t vdup_lane_p8 (poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x1_t vdup_lane_u64 (uint64x1_t, const int) +@end itemize + + +@itemize @bullet +@item int64x1_t vdup_lane_s64 (int64x1_t, const int) +@end itemize + + +@itemize @bullet +@item uint32x4_t vdupq_lane_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vdupq_lane_u16 (uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint8x16_t vdupq_lane_u8 (uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vdupq_lane_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vdupq_lane_s16 (int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int8x16_t vdupq_lane_s8 (int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vdupq_lane_f32 (float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.32 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly16x8_t vdupq_lane_p16 (poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.16 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item poly8x16_t vdupq_lane_p8 (poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vdup.8 @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vdupq_lane_u64 (uint64x1_t, const int) +@end itemize + + +@itemize @bullet +@item int64x2_t vdupq_lane_s64 (int64x1_t, const int) +@end itemize + + + + +@subsubsection Combining vectors + +@itemize @bullet +@item uint32x4_t vcombine_u32 (uint32x2_t, uint32x2_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vcombine_u16 (uint16x4_t, uint16x4_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vcombine_u8 (uint8x8_t, uint8x8_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vcombine_s32 (int32x2_t, int32x2_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vcombine_s16 (int16x4_t, int16x4_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vcombine_s8 (int8x8_t, int8x8_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vcombine_u64 (uint64x1_t, uint64x1_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vcombine_s64 (int64x1_t, int64x1_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vcombine_f32 (float32x2_t, float32x2_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vcombine_p16 (poly16x4_t, poly16x4_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vcombine_p8 (poly8x8_t, poly8x8_t) +@end itemize + + + + +@subsubsection Splitting vectors + +@itemize @bullet +@item uint32x2_t vget_high_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vget_high_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vget_high_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vget_high_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vget_high_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vget_high_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vget_high_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vget_high_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vget_high_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vget_high_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vget_high_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vget_low_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vget_low_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vget_low_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vget_low_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vget_low_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vget_low_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vget_low_u64 (uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vget_low_s64 (int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vget_low_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vget_low_p16 (poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vget_low_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vmov @var{d0}, @var{d0}} +@end itemize + + + + +@subsubsection Conversions + +@itemize @bullet +@item float32x2_t vcvt_f32_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.u32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vcvt_f32_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.s32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcvt_u32_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.u32.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vcvt_s32_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.s32.f32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vcvtq_f32_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.u32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vcvtq_f32_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.s32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcvtq_u32_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.u32.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vcvtq_s32_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vcvt.s32.f32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vcvt_n_f32_u32 (uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.u32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vcvt_n_f32_s32 (int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.s32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vcvt_n_u32_f32 (float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.u32.f32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vcvt_n_s32_f32 (float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.s32.f32 @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vcvtq_n_f32_u32 (uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.u32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vcvtq_n_f32_s32 (int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.f32.s32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vcvtq_n_u32_f32 (float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.u32.f32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vcvtq_n_s32_f32 (float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vcvt.s32.f32 @var{q0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Move, single_opcode narrowing + +@itemize @bullet +@item uint32x2_t vmovn_u64 (uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i64 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmovn_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i32 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vmovn_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i16 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vmovn_s64 (int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i64 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vmovn_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i32 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vmovn_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vmovn.i16 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqmovn_u64 (uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.u64 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqmovn_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.u32 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqmovn_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.u16 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vqmovn_s64 (int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.s64 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vqmovn_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.s32 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vqmovn_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqmovn.s16 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint32x2_t vqmovun_s64 (int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vqmovun.s64 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vqmovun_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vqmovun.s32 @var{d0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vqmovun_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vqmovun.s16 @var{d0}, @var{q0}} +@end itemize + + + + +@subsubsection Move, single_opcode long + +@itemize @bullet +@item uint64x2_t vmovl_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.u32 @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmovl_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.u16 @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmovl_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.u8 @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vmovl_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.s32 @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vmovl_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.s16 @var{q0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vmovl_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vmovl.s8 @var{q0}, @var{d0}} +@end itemize + + + + +@subsubsection Table lookup + +@itemize @bullet +@item poly8x8_t vtbl1_p8 (poly8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbl1_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbl1_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbl2_p8 (poly8x8x2_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbl2_s8 (int8x8x2_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbl2_u8 (uint8x8x2_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbl3_p8 (poly8x8x3_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbl3_s8 (int8x8x3_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbl3_u8 (uint8x8x3_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbl4_p8 (poly8x8x4_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbl4_s8 (int8x8x4_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbl4_u8 (uint8x8x4_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbl.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + + + +@subsubsection Extended table lookup + +@itemize @bullet +@item poly8x8_t vtbx1_p8 (poly8x8_t, poly8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbx1_s8 (int8x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbx1_u8 (uint8x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbx2_p8 (poly8x8_t, poly8x8x2_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbx2_s8 (int8x8_t, int8x8x2_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbx2_u8 (uint8x8_t, uint8x8x2_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbx3_p8 (poly8x8_t, poly8x8x3_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbx3_s8 (int8x8_t, int8x8x3_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbx3_u8 (uint8x8_t, uint8x8x3_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vtbx4_p8 (poly8x8_t, poly8x8x4_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vtbx4_s8 (int8x8_t, int8x8x4_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vtbx4_u8 (uint8x8_t, uint8x8x4_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtbx.8 @var{d0}, @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, @var{d0}} +@end itemize + + + + +@subsubsection Multiply, lane + +@itemize @bullet +@item float32x2_t vmul_lane_f32 (float32x2_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmul_lane_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmul_lane_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmul_lane_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmul_lane_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmulq_lane_f32 (float32x4_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmulq_lane_u32 (uint32x4_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmulq_lane_u16 (uint16x8_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmulq_lane_s32 (int32x4_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmulq_lane_s16 (int16x8_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Long multiply, lane + +@itemize @bullet +@item uint64x2_t vmull_lane_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmull.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmull_lane_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmull.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmull_lane_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmull.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmull_lane_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmull.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Saturating doubling long multiply, lane + +@itemize @bullet +@item int64x2_t vqdmull_lane_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmull_lane_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Saturating doubling multiply high, lane + +@itemize @bullet +@item int32x4_t vqdmulhq_lane_s32 (int32x4_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vqdmulhq_lane_s16 (int16x8_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vqdmulh_lane_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vqdmulh_lane_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqrdmulhq_lane_s32 (int32x4_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vqrdmulhq_lane_s16 (int16x8_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vqrdmulh_lane_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vqrdmulh_lane_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Multiply-accumulate, lane + +@itemize @bullet +@item float32x2_t vmla_lane_f32 (float32x2_t, float32x2_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmla_lane_u32 (uint32x2_t, uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmla_lane_u16 (uint16x4_t, uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmla_lane_s32 (int32x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmla_lane_s16 (int16x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlaq_lane_f32 (float32x4_t, float32x4_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlaq_lane_u32 (uint32x4_t, uint32x4_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlaq_lane_u16 (uint16x8_t, uint16x8_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlaq_lane_s32 (int32x4_t, int32x4_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlaq_lane_s16 (int16x8_t, int16x8_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlal_lane_u32 (uint64x2_t, uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlal.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlal_lane_u16 (uint32x4_t, uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlal.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlal_lane_s32 (int64x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlal.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlal_lane_s16 (int32x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlal.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlal_lane_s32 (int64x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlal_lane_s16 (int32x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Multiply-subtract, lane + +@itemize @bullet +@item float32x2_t vmls_lane_f32 (float32x2_t, float32x2_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmls_lane_u32 (uint32x2_t, uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmls_lane_u16 (uint16x4_t, uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmls_lane_s32 (int32x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmls_lane_s16 (int16x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlsq_lane_f32 (float32x4_t, float32x4_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsq_lane_u32 (uint32x4_t, uint32x4_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlsq_lane_u16 (uint16x8_t, uint16x8_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsq_lane_s32 (int32x4_t, int32x4_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlsq_lane_s16 (int16x8_t, int16x8_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlsl_lane_u32 (uint64x2_t, uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsl_lane_u16 (uint32x4_t, uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlsl_lane_s32 (int64x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsl_lane_s16 (int32x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlsl_lane_s32 (int64x2_t, int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlsl_lane_s16 (int32x4_t, int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector multiply by scalar + +@itemize @bullet +@item float32x2_t vmul_n_f32 (float32x2_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmul_n_u32 (uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmul_n_u16 (uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmul_n_s32 (int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmul_n_s16 (int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmulq_n_f32 (float32x4_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmulq_n_u32 (uint32x4_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmulq_n_u16 (uint16x8_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmulq_n_s32 (int32x4_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmulq_n_s16 (int16x8_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmul.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector long multiply by scalar + +@itemize @bullet +@item uint64x2_t vmull_n_u32 (uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmull.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmull_n_u16 (uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmull.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmull_n_s32 (int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmull.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmull_n_s16 (int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmull.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector saturating doubling long multiply by scalar + +@itemize @bullet +@item int64x2_t vqdmull_n_s32 (int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmull_n_s16 (int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqdmull.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector saturating doubling multiply high by scalar + +@itemize @bullet +@item int32x4_t vqdmulhq_n_s32 (int32x4_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vqdmulhq_n_s16 (int16x8_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vqdmulh_n_s32 (int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vqdmulh_n_s16 (int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqdmulh.s16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqrdmulhq_n_s32 (int32x4_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vqrdmulhq_n_s16 (int16x8_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vqrdmulh_n_s32 (int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vqrdmulh_n_s16 (int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqrdmulh.s16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector multiply-accumulate by scalar + +@itemize @bullet +@item float32x2_t vmla_n_f32 (float32x2_t, float32x2_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmla_n_u32 (uint32x2_t, uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmla_n_u16 (uint16x4_t, uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmla_n_s32 (int32x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmla_n_s16 (int16x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlaq_n_f32 (float32x4_t, float32x4_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlaq_n_u32 (uint32x4_t, uint32x4_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlaq_n_u16 (uint16x8_t, uint16x8_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlaq_n_s32 (int32x4_t, int32x4_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlaq_n_s16 (int16x8_t, int16x8_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmla.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlal_n_u32 (uint64x2_t, uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlal_n_u16 (uint32x4_t, uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlal_n_s32 (int64x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlal_n_s16 (int32x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmlal.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlal_n_s32 (int64x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlal_n_s16 (int32x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlal.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector multiply-subtract by scalar + +@itemize @bullet +@item float32x2_t vmls_n_f32 (float32x2_t, float32x2_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vmls_n_u32 (uint32x2_t, uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vmls_n_u16 (uint16x4_t, uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vmls_n_s32 (int32x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vmls_n_s16 (int16x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{d0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vmlsq_n_f32 (float32x4_t, float32x4_t, float32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.f32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsq_n_u32 (uint32x4_t, uint32x4_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vmlsq_n_u16 (uint16x8_t, uint16x8_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsq_n_s32 (int32x4_t, int32x4_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i32 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vmlsq_n_s16 (int16x8_t, int16x8_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmls.i16 @var{q0}, @var{q0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vmlsl_n_u32 (uint64x2_t, uint32x2_t, uint32_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vmlsl_n_u16 (uint32x4_t, uint16x4_t, uint16_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.u16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vmlsl_n_s32 (int64x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vmlsl_n_s16 (int32x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vmlsl.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vqdmlsl_n_s32 (int64x2_t, int32x2_t, int32_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s32 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vqdmlsl_n_s16 (int32x4_t, int16x4_t, int16_t) +@*@emph{Form of expected instruction(s):} @code{vqdmlsl.s16 @var{q0}, @var{d0}, @var{d0}[@var{0}]} +@end itemize + + + + +@subsubsection Vector extract + +@itemize @bullet +@item uint32x2_t vext_u32 (uint32x2_t, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vext_u16 (uint16x4_t, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vext_u8 (uint8x8_t, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vext_s32 (int32x2_t, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vext_s16 (int16x4_t, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vext_s8 (int8x8_t, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vext_u64 (uint64x1_t, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.64 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vext_s64 (int64x1_t, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.64 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vext_f32 (float32x2_t, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vext_p16 (poly16x4_t, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vext_p8 (poly8x8_t, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{d0}, @var{d0}, @var{d0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vextq_u32 (uint32x4_t, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vextq_u16 (uint16x8_t, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vextq_u8 (uint8x16_t, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vextq_s32 (int32x4_t, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vextq_s16 (int16x8_t, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vextq_s8 (int8x16_t, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vextq_u64 (uint64x2_t, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.64 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vextq_s64 (int64x2_t, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.64 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vextq_f32 (float32x4_t, float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.32 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vextq_p16 (poly16x8_t, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.16 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vextq_p8 (poly8x16_t, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vext.8 @var{q0}, @var{q0}, @var{q0}, #@var{0}} +@end itemize + + + + +@subsubsection Reverse elements + +@itemize @bullet +@item uint32x2_t vrev64_u32 (uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrev64_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrev64_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vrev64_s32 (int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrev64_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrev64_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vrev64_f32 (float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vrev64_p16 (poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vrev64_p8 (poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vrev64q_u32 (uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrev64q_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrev64q_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vrev64q_s32 (int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrev64q_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrev64q_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vrev64q_f32 (float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.32 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vrev64q_p16 (poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vrev64q_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev64.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vrev32_u16 (uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vrev32_s16 (int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrev32_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrev32_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vrev32_p16 (poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vrev32_p8 (poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vrev32q_u16 (uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vrev32q_s16 (int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrev32q_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrev32q_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vrev32q_p16 (poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.16 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vrev32q_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev32.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vrev16_u8 (uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vrev16_s8 (int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vrev16_p8 (poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vrev16q_u8 (uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vrev16q_s8 (int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vrev16q_p8 (poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vrev16.8 @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Bit selection + +@itemize @bullet +@item uint32x2_t vbsl_u32 (uint32x2_t, uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vbsl_u16 (uint16x4_t, uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vbsl_u8 (uint8x8_t, uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vbsl_s32 (uint32x2_t, int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vbsl_s16 (uint16x4_t, int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vbsl_s8 (uint8x8_t, int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vbsl_u64 (uint64x1_t, uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vbsl_s64 (uint64x1_t, int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item float32x2_t vbsl_f32 (uint32x2_t, float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly16x4_t vbsl_p16 (uint16x4_t, poly16x4_t, poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item poly8x8_t vbsl_p8 (uint8x8_t, poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbit @var{d0}, @var{d0}, @var{d0}} @emph{or} @code{vbif @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vbslq_u32 (uint32x4_t, uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vbslq_u16 (uint16x8_t, uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vbslq_u8 (uint8x16_t, uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vbslq_s32 (uint32x4_t, int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vbslq_s16 (uint16x8_t, int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vbslq_s8 (uint8x16_t, int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vbslq_u64 (uint64x2_t, uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vbslq_s64 (uint64x2_t, int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item float32x4_t vbslq_f32 (uint32x4_t, float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly16x8_t vbslq_p16 (uint16x8_t, poly16x8_t, poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item poly8x16_t vbslq_p8 (uint8x16_t, poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vbsl @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbit @var{q0}, @var{q0}, @var{q0}} @emph{or} @code{vbif @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Transpose elements + +@itemize @bullet +@item uint32x2x2_t vtrn_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vtrn_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vtrn_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vtrn_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vtrn_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vtrn_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vtrn_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vtrn_p16 (poly16x4_t, poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vtrn_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint32x4x2_t vtrnq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint16x8x2_t vtrnq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint8x16x2_t vtrnq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int32x4x2_t vtrnq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int16x8x2_t vtrnq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int8x16x2_t vtrnq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item float32x4x2_t vtrnq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly16x8x2_t vtrnq_p16 (poly16x8_t, poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly8x16x2_t vtrnq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vtrn.8 @var{q0}, @var{q1}} +@end itemize + + + + +@subsubsection Zip elements + +@itemize @bullet +@item uint32x2x2_t vzip_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vzip_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vzip_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vzip_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vzip_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vzip_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vzip_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vzip_p16 (poly16x4_t, poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vzip_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint32x4x2_t vzipq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint16x8x2_t vzipq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint8x16x2_t vzipq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int32x4x2_t vzipq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int16x8x2_t vzipq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int8x16x2_t vzipq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item float32x4x2_t vzipq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vzip.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly16x8x2_t vzipq_p16 (poly16x8_t, poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vzip.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly8x16x2_t vzipq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vzip.8 @var{q0}, @var{q1}} +@end itemize + + + + +@subsubsection Unzip elements + +@itemize @bullet +@item uint32x2x2_t vuzp_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vuzp_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vuzp_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vuzp_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vuzp_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vuzp_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vuzp_f32 (float32x2_t, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vuzp_p16 (poly16x4_t, poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vuzp_p8 (poly8x8_t, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{d0}, @var{d1}} +@end itemize + + +@itemize @bullet +@item uint32x4x2_t vuzpq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint16x8x2_t vuzpq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item uint8x16x2_t vuzpq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int32x4x2_t vuzpq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int16x8x2_t vuzpq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item int8x16x2_t vuzpq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item float32x4x2_t vuzpq_f32 (float32x4_t, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.32 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly16x8x2_t vuzpq_p16 (poly16x8_t, poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.16 @var{q0}, @var{q1}} +@end itemize + + +@itemize @bullet +@item poly8x16x2_t vuzpq_p8 (poly8x16_t, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vuzp.8 @var{q0}, @var{q1}} +@end itemize + + + + +@subsubsection Element/structure loads, VLD1 variants + +@itemize @bullet +@item uint32x2_t vld1_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vld1_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8_t vld1_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vld1_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vld1_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8_t vld1_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1_t vld1_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1_t vld1_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2_t vld1_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4_t vld1_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8_t vld1_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vld1q_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vld1q_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16_t vld1q_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vld1q_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vld1q_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16_t vld1q_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vld1q_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vld1q_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vld1q_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8_t vld1q_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16_t vld1q_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vld1_lane_u32 (const uint32_t *, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vld1_lane_u16 (const uint16_t *, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8_t vld1_lane_u8 (const uint8_t *, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vld1_lane_s32 (const int32_t *, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vld1_lane_s16 (const int16_t *, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8_t vld1_lane_s8 (const int8_t *, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2_t vld1_lane_f32 (const float32_t *, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4_t vld1_lane_p16 (const poly16_t *, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8_t vld1_lane_p8 (const poly8_t *, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1_t vld1_lane_u64 (const uint64_t *, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1_t vld1_lane_s64 (const int64_t *, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vld1q_lane_u32 (const uint32_t *, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vld1q_lane_u16 (const uint16_t *, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16_t vld1q_lane_u8 (const uint8_t *, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vld1q_lane_s32 (const int32_t *, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vld1q_lane_s16 (const int16_t *, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16_t vld1q_lane_s8 (const int8_t *, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vld1q_lane_f32 (const float32_t *, float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8_t vld1q_lane_p16 (const poly16_t *, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16_t vld1q_lane_p8 (const poly8_t *, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vld1q_lane_u64 (const uint64_t *, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vld1q_lane_s64 (const int64_t *, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2_t vld1_dup_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4_t vld1_dup_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8_t vld1_dup_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2_t vld1_dup_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4_t vld1_dup_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8_t vld1_dup_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2_t vld1_dup_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4_t vld1_dup_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8_t vld1_dup_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1_t vld1_dup_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1_t vld1_dup_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4_t vld1q_dup_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8_t vld1q_dup_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16_t vld1q_dup_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4_t vld1q_dup_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8_t vld1q_dup_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16_t vld1q_dup_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4_t vld1q_dup_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8_t vld1q_dup_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16_t vld1q_dup_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x2_t vld1q_dup_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x2_t vld1q_dup_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure stores, VST1 variants + +@itemize @bullet +@item void vst1_u32 (uint32_t *, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_u16 (uint16_t *, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_u8 (uint8_t *, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_s32 (int32_t *, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_s16 (int16_t *, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_s8 (int8_t *, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_u64 (uint64_t *, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_s64 (int64_t *, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_f32 (float32_t *, float32x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_p16 (poly16_t *, poly16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_p8 (poly8_t *, poly8x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_u32 (uint32_t *, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_u16 (uint16_t *, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_u8 (uint8_t *, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_s32 (int32_t *, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_s16 (int16_t *, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_s8 (int8_t *, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_u64 (uint64_t *, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_s64 (int64_t *, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_f32 (float32_t *, float32x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_p16 (poly16_t *, poly16x8_t) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_p8 (poly8_t *, poly8x16_t) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_u32 (uint32_t *, uint32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_u16 (uint16_t *, uint16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_u8 (uint8_t *, uint8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_s32 (int32_t *, int32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_s16 (int16_t *, int16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_s8 (int8_t *, int8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_f32 (float32_t *, float32x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_p16 (poly16_t *, poly16x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_p8 (poly8_t *, poly8x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_s64 (int64_t *, int64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1_lane_u64 (uint64_t *, uint64x1_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_u32 (uint32_t *, uint32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_u16 (uint16_t *, uint16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_u8 (uint8_t *, uint8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_s32 (int32_t *, int32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_s16 (int16_t *, int16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_s8 (int8_t *, int8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_f32 (float32_t *, float32x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.32 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_p16 (poly16_t *, poly16x8_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.16 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_p8 (poly8_t *, poly8x16_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.8 @{@var{d0}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_s64 (int64_t *, int64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst1q_lane_u64 (uint64_t *, uint64x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure loads, VLD2 variants + +@itemize @bullet +@item uint32x2x2_t vld2_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vld2_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vld2_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vld2_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vld2_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vld2_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vld2_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vld2_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vld2_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x2_t vld2_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x2_t vld2_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x2_t vld2q_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x2_t vld2q_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16x2_t vld2q_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x2_t vld2q_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x2_t vld2q_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16x2_t vld2q_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x2_t vld2q_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x2_t vld2q_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16x2_t vld2q_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x2_t vld2_lane_u32 (const uint32_t *, uint32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vld2_lane_u16 (const uint16_t *, uint16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vld2_lane_u8 (const uint8_t *, uint8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vld2_lane_s32 (const int32_t *, int32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vld2_lane_s16 (const int16_t *, int16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vld2_lane_s8 (const int8_t *, int8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vld2_lane_f32 (const float32_t *, float32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vld2_lane_p16 (const poly16_t *, poly16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vld2_lane_p8 (const poly8_t *, poly8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x2_t vld2q_lane_s32 (const int32_t *, int32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x2_t vld2q_lane_s16 (const int16_t *, int16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x2_t vld2q_lane_u32 (const uint32_t *, uint32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x2_t vld2q_lane_u16 (const uint16_t *, uint16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x2_t vld2q_lane_f32 (const float32_t *, float32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x2_t vld2q_lane_p16 (const poly16_t *, poly16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x2_t vld2_dup_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x2_t vld2_dup_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x2_t vld2_dup_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x2_t vld2_dup_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x2_t vld2_dup_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x2_t vld2_dup_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x2_t vld2_dup_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.32 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x2_t vld2_dup_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.16 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x2_t vld2_dup_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld2.8 @{@var{d0}[], @var{d1}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x2_t vld2_dup_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x2_t vld2_dup_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure stores, VST2 variants + +@itemize @bullet +@item void vst2_u32 (uint32_t *, uint32x2x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_u16 (uint16_t *, uint16x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_u8 (uint8_t *, uint8x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_s32 (int32_t *, int32x2x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_s16 (int16_t *, int16x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_s8 (int8_t *, int8x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_f32 (float32_t *, float32x2x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_p16 (poly16_t *, poly16x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_p8 (poly8_t *, poly8x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_u64 (uint64_t *, uint64x1x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_s64 (int64_t *, int64x1x2_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_u32 (uint32_t *, uint32x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_u16 (uint16_t *, uint16x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_u8 (uint8_t *, uint8x16x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_s32 (int32_t *, int32x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_s16 (int16_t *, int16x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_s8 (int8_t *, int8x16x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_f32 (float32_t *, float32x4x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_p16 (poly16_t *, poly16x8x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_p8 (poly8_t *, poly8x16x2_t) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}, @var{d1}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_u32 (uint32_t *, uint32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_u16 (uint16_t *, uint16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_u8 (uint8_t *, uint8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_s32 (int32_t *, int32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_s16 (int16_t *, int16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_s8 (int8_t *, int8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_f32 (float32_t *, float32x2x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_p16 (poly16_t *, poly16x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2_lane_p8 (poly8_t *, poly8x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_s32 (int32_t *, int32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_s16 (int16_t *, int16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_u32 (uint32_t *, uint32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_u16 (uint16_t *, uint16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_f32 (float32_t *, float32x4x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst2q_lane_p16 (poly16_t *, poly16x8x2_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst2.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}]@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure loads, VLD3 variants + +@itemize @bullet +@item uint32x2x3_t vld3_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x3_t vld3_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x3_t vld3_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x3_t vld3_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x3_t vld3_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x3_t vld3_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x3_t vld3_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x3_t vld3_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x3_t vld3_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x3_t vld3_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x3_t vld3_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x3_t vld3q_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x3_t vld3q_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16x3_t vld3q_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x3_t vld3q_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x3_t vld3q_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16x3_t vld3q_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x3_t vld3q_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x3_t vld3q_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16x3_t vld3q_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x3_t vld3_lane_u32 (const uint32_t *, uint32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x3_t vld3_lane_u16 (const uint16_t *, uint16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x3_t vld3_lane_u8 (const uint8_t *, uint8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x3_t vld3_lane_s32 (const int32_t *, int32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x3_t vld3_lane_s16 (const int16_t *, int16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x3_t vld3_lane_s8 (const int8_t *, int8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x3_t vld3_lane_f32 (const float32_t *, float32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x3_t vld3_lane_p16 (const poly16_t *, poly16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x3_t vld3_lane_p8 (const poly8_t *, poly8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x3_t vld3q_lane_s32 (const int32_t *, int32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x3_t vld3q_lane_s16 (const int16_t *, int16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x3_t vld3q_lane_u32 (const uint32_t *, uint32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x3_t vld3q_lane_u16 (const uint16_t *, uint16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x3_t vld3q_lane_f32 (const float32_t *, float32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x3_t vld3q_lane_p16 (const poly16_t *, poly16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x3_t vld3_dup_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x3_t vld3_dup_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x3_t vld3_dup_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x3_t vld3_dup_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x3_t vld3_dup_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x3_t vld3_dup_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x3_t vld3_dup_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.32 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x3_t vld3_dup_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.16 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x3_t vld3_dup_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld3.8 @{@var{d0}[], @var{d1}[], @var{d2}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x3_t vld3_dup_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x3_t vld3_dup_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure stores, VST3 variants + +@itemize @bullet +@item void vst3_u32 (uint32_t *, uint32x2x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_u16 (uint16_t *, uint16x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_u8 (uint8_t *, uint8x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_s32 (int32_t *, int32x2x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_s16 (int16_t *, int16x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_s8 (int8_t *, int8x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_f32 (float32_t *, float32x2x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_p16 (poly16_t *, poly16x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_p8 (poly8_t *, poly8x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_u64 (uint64_t *, uint64x1x3_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_s64 (int64_t *, int64x1x3_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_u32 (uint32_t *, uint32x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_u16 (uint16_t *, uint16x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_u8 (uint8_t *, uint8x16x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_s32 (int32_t *, int32x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_s16 (int16_t *, int16x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_s8 (int8_t *, int8x16x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_f32 (float32_t *, float32x4x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_p16 (poly16_t *, poly16x8x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_p8 (poly8_t *, poly8x16x3_t) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}, @var{d1}, @var{d2}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_u32 (uint32_t *, uint32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_u16 (uint16_t *, uint16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_u8 (uint8_t *, uint8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_s32 (int32_t *, int32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_s16 (int16_t *, int16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_s8 (int8_t *, int8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_f32 (float32_t *, float32x2x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_p16 (poly16_t *, poly16x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3_lane_p8 (poly8_t *, poly8x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_s32 (int32_t *, int32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_s16 (int16_t *, int16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_u32 (uint32_t *, uint32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_u16 (uint16_t *, uint16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_f32 (float32_t *, float32x4x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst3q_lane_p16 (poly16_t *, poly16x8x3_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst3.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}]@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure loads, VLD4 variants + +@itemize @bullet +@item uint32x2x4_t vld4_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x4_t vld4_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x4_t vld4_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x4_t vld4_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x4_t vld4_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x4_t vld4_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x4_t vld4_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x4_t vld4_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x4_t vld4_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x4_t vld4_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x4_t vld4_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x4_t vld4q_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x4_t vld4q_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x16x4_t vld4q_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x4_t vld4q_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x4_t vld4q_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x16x4_t vld4q_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x4_t vld4q_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x4_t vld4q_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x16x4_t vld4q_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x4_t vld4_lane_u32 (const uint32_t *, uint32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x4_t vld4_lane_u16 (const uint16_t *, uint16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x4_t vld4_lane_u8 (const uint8_t *, uint8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x4_t vld4_lane_s32 (const int32_t *, int32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x4_t vld4_lane_s16 (const int16_t *, int16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x4_t vld4_lane_s8 (const int8_t *, int8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x4_t vld4_lane_f32 (const float32_t *, float32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x4_t vld4_lane_p16 (const poly16_t *, poly16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x4_t vld4_lane_p8 (const poly8_t *, poly8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x4x4_t vld4q_lane_s32 (const int32_t *, int32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x8x4_t vld4q_lane_s16 (const int16_t *, int16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x4x4_t vld4q_lane_u32 (const uint32_t *, uint32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x8x4_t vld4q_lane_u16 (const uint16_t *, uint16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x4x4_t vld4q_lane_f32 (const float32_t *, float32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x8x4_t vld4q_lane_p16 (const poly16_t *, poly16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint32x2x4_t vld4_dup_u32 (const uint32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint16x4x4_t vld4_dup_u16 (const uint16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint8x8x4_t vld4_dup_u8 (const uint8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int32x2x4_t vld4_dup_s32 (const int32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int16x4x4_t vld4_dup_s16 (const int16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int8x8x4_t vld4_dup_s8 (const int8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item float32x2x4_t vld4_dup_f32 (const float32_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.32 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly16x4x4_t vld4_dup_p16 (const poly16_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.16 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item poly8x8x4_t vld4_dup_p8 (const poly8_t *) +@*@emph{Form of expected instruction(s):} @code{vld4.8 @{@var{d0}[], @var{d1}[], @var{d2}[], @var{d3}[]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item uint64x1x4_t vld4_dup_u64 (const uint64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item int64x1x4_t vld4_dup_s64 (const int64_t *) +@*@emph{Form of expected instruction(s):} @code{vld1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Element/structure stores, VST4 variants + +@itemize @bullet +@item void vst4_u32 (uint32_t *, uint32x2x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_u16 (uint16_t *, uint16x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_u8 (uint8_t *, uint8x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_s32 (int32_t *, int32x2x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_s16 (int16_t *, int16x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_s8 (int8_t *, int8x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_f32 (float32_t *, float32x2x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_p16 (poly16_t *, poly16x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_p8 (poly8_t *, poly8x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_u64 (uint64_t *, uint64x1x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_s64 (int64_t *, int64x1x4_t) +@*@emph{Form of expected instruction(s):} @code{vst1.64 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_u32 (uint32_t *, uint32x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_u16 (uint16_t *, uint16x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_u8 (uint8_t *, uint8x16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_s32 (int32_t *, int32x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_s16 (int16_t *, int16x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_s8 (int8_t *, int8x16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_f32 (float32_t *, float32x4x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_p16 (poly16_t *, poly16x8x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_p8 (poly8_t *, poly8x16x4_t) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}, @var{d1}, @var{d2}, @var{d3}@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_u32 (uint32_t *, uint32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_u16 (uint16_t *, uint16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_u8 (uint8_t *, uint8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_s32 (int32_t *, int32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_s16 (int16_t *, int16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_s8 (int8_t *, int8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_f32 (float32_t *, float32x2x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_p16 (poly16_t *, poly16x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4_lane_p8 (poly8_t *, poly8x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.8 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_s32 (int32_t *, int32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_s16 (int16_t *, int16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_u32 (uint32_t *, uint32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_u16 (uint16_t *, uint16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_f32 (float32_t *, float32x4x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.32 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + +@itemize @bullet +@item void vst4q_lane_p16 (poly16_t *, poly16x8x4_t, const int) +@*@emph{Form of expected instruction(s):} @code{vst4.16 @{@var{d0}[@var{0}], @var{d1}[@var{0}], @var{d2}[@var{0}], @var{d3}[@var{0}]@}, [@var{r0}]} +@end itemize + + + + +@subsubsection Logical operations (AND) + +@itemize @bullet +@item uint32x2_t vand_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vand_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vand_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vand_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vand_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vand_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vand_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vand_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vandq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vandq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vandq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vandq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vandq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vandq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vandq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vandq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vand @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Logical operations (OR) + +@itemize @bullet +@item uint32x2_t vorr_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vorr_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vorr_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vorr_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vorr_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vorr_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vorr_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vorr_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vorrq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vorrq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vorrq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vorrq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vorrq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vorrq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vorrq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vorrq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vorr @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Logical operations (exclusive OR) + +@itemize @bullet +@item uint32x2_t veor_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t veor_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t veor_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t veor_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t veor_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t veor_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t veor_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t veor_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t veorq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t veorq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t veorq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t veorq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t veorq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t veorq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t veorq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t veorq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{veor @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Logical operations (AND-NOT) + +@itemize @bullet +@item uint32x2_t vbic_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vbic_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vbic_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vbic_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vbic_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vbic_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vbic_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vbic_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vbicq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vbicq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vbicq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vbicq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vbicq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vbicq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vbicq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vbicq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vbic @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Logical operations (OR-NOT) + +@itemize @bullet +@item uint32x2_t vorn_u32 (uint32x2_t, uint32x2_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint16x4_t vorn_u16 (uint16x4_t, uint16x4_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint8x8_t vorn_u8 (uint8x8_t, uint8x8_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int32x2_t vorn_s32 (int32x2_t, int32x2_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int16x4_t vorn_s16 (int16x4_t, int16x4_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int8x8_t vorn_s8 (int8x8_t, int8x8_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint64x1_t vorn_u64 (uint64x1_t, uint64x1_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item int64x1_t vorn_s64 (int64x1_t, int64x1_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{d0}, @var{d0}, @var{d0}} +@end itemize + + +@itemize @bullet +@item uint32x4_t vornq_u32 (uint32x4_t, uint32x4_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint16x8_t vornq_u16 (uint16x8_t, uint16x8_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint8x16_t vornq_u8 (uint8x16_t, uint8x16_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int32x4_t vornq_s32 (int32x4_t, int32x4_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int16x8_t vornq_s16 (int16x8_t, int16x8_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int8x16_t vornq_s8 (int8x16_t, int8x16_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item uint64x2_t vornq_u64 (uint64x2_t, uint64x2_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + +@itemize @bullet +@item int64x2_t vornq_s64 (int64x2_t, int64x2_t) +@*@emph{Form of expected instruction(s):} @code{vorn @var{q0}, @var{q0}, @var{q0}} +@end itemize + + + + +@subsubsection Reinterpret casts + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item poly8x8_t vreinterpret_p8_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item poly8x16_t vreinterpretq_p8_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item poly16x4_t vreinterpret_p16_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item poly16x8_t vreinterpretq_p16_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item float32x2_t vreinterpret_f32_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item float32x4_t vreinterpretq_f32_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item int64x1_t vreinterpret_s64_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item int64x2_t vreinterpretq_s64_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item uint64x1_t vreinterpret_u64_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item uint64x2_t vreinterpretq_u64_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item int8x8_t vreinterpret_s8_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item int8x16_t vreinterpretq_s8_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item int16x4_t vreinterpret_s16_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item int16x8_t vreinterpretq_s16_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item int32x2_t vreinterpret_s32_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item int32x4_t vreinterpretq_s32_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item uint8x8_t vreinterpret_u8_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item uint8x16_t vreinterpretq_u8_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_u32 (uint32x2_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item uint16x4_t vreinterpret_u16_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_u32 (uint32x4_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item uint16x8_t vreinterpretq_u16_p8 (poly8x16_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_u16 (uint16x4_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_u8 (uint8x8_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_s32 (int32x2_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_s16 (int16x4_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_s8 (int8x8_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_u64 (uint64x1_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_s64 (int64x1_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_f32 (float32x2_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_p16 (poly16x4_t) +@end itemize + + +@itemize @bullet +@item uint32x2_t vreinterpret_u32_p8 (poly8x8_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_u16 (uint16x8_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_u8 (uint8x16_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_s32 (int32x4_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_s16 (int16x8_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_s8 (int8x16_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_u64 (uint64x2_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_s64 (int64x2_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_f32 (float32x4_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_p16 (poly16x8_t) +@end itemize + + +@itemize @bullet +@item uint32x4_t vreinterpretq_u32_p8 (poly8x16_t) +@end itemize + + + + diff --git a/gcc-4.2.1-5666.3/gcc/doc/bugreport.texi b/gcc-4.2.1-5666.3/gcc/doc/bugreport.texi new file mode 100644 index 000000000..9e10af910 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/bugreport.texi @@ -0,0 +1,94 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Bugs +@chapter Reporting Bugs +@cindex bugs +@cindex reporting bugs + +Your bug reports play an essential role in making GCC reliable. + +When you encounter a problem, the first thing to do is to see if it is +already known. @xref{Trouble}. If it isn't known, then you should +report the problem. + +@menu +* Criteria: Bug Criteria. Have you really found a bug? +* Reporting: Bug Reporting. How to report a bug effectively. +* Known: Trouble. Known problems. +* Help: Service. Where to ask for help. +@end menu + +@node Bug Criteria,Bug Reporting,,Bugs +@section Have You Found a Bug? +@cindex bug criteria + +If you are not sure whether you have found a bug, here are some guidelines: + +@itemize @bullet +@cindex fatal signal +@cindex core dump +@item +If the compiler gets a fatal signal, for any input whatever, that is a +compiler bug. Reliable compilers never crash. + +@cindex invalid assembly code +@cindex assembly code, invalid +@item +If the compiler produces invalid assembly code, for any input whatever +(except an @code{asm} statement), that is a compiler bug, unless the +compiler reports errors (not just warnings) which would ordinarily +prevent the assembler from being run. + +@cindex undefined behavior +@cindex undefined function value +@cindex increment operators +@item +If the compiler produces valid assembly code that does not correctly +execute the input source code, that is a compiler bug. + +However, you must double-check to make sure, because you may have a +program whose behavior is undefined, which happened by chance to give +the desired results with another C or C++ compiler. + +For example, in many nonoptimizing compilers, you can write @samp{x;} +at the end of a function instead of @samp{return x;}, with the same +results. But the value of the function is undefined if @code{return} +is omitted; it is not a bug when GCC produces different results. + +Problems often result from expressions with two increment operators, +as in @code{f (*p++, *p++)}. Your previous compiler might have +interpreted that expression the way you intended; GCC might +interpret it another way. Neither compiler is wrong. The bug is +in your code. + +After you have localized the error to a single source line, it should +be easy to check for these things. If your program is correct and +well defined, you have found a compiler bug. + +@item +If the compiler produces an error message for valid input, that is a +compiler bug. + +@cindex invalid input +@item +If the compiler does not produce an error message for invalid input, +that is a compiler bug. However, you should note that your idea of +``invalid input'' might be someone else's idea of ``an extension'' or +``support for traditional practice''. + +@item +If you are an experienced user of one of the languages GCC supports, your +suggestions for improvement of GCC are welcome in any case. +@end itemize + +@node Bug Reporting,,Bug Criteria,Bugs +@section How and where to Report Bugs +@cindex compiler bugs, reporting + +Bugs should be reported to the GCC bug database. Please refer to +@uref{http://gcc.gnu.org/bugs.html} for up-to-date instructions how to +submit bug reports. Copies of this file in HTML (@file{bugs.html}) and +plain text (@file{BUGS}) are also part of GCC releases. diff --git a/gcc-4.2.1-5666.3/gcc/doc/c-tree.texi b/gcc-4.2.1-5666.3/gcc/doc/c-tree.texi new file mode 100644 index 000000000..df08021d0 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/c-tree.texi @@ -0,0 +1,2743 @@ +@c Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005 +@c Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Trees +@c --------------------------------------------------------------------- + +@node Trees +@chapter Trees: The intermediate representation used by the C and C++ front ends +@cindex Trees +@cindex C/C++ Internal Representation + +This chapter documents the internal representation used by GCC to +represent C and C++ source programs. When presented with a C or C++ +source program, GCC parses the program, performs semantic analysis +(including the generation of error messages), and then produces the +internal representation described here. This representation contains a +complete representation for the entire translation unit provided as +input to the front end. This representation is then typically processed +by a code-generator in order to produce machine code, but could also be +used in the creation of source browsers, intelligent editors, automatic +documentation generators, interpreters, and any other programs needing +the ability to process C or C++ code. + +This chapter explains the internal representation. In particular, it +documents the internal representation for C and C++ source +constructs, and the macros, functions, and variables that can be used to +access these constructs. The C++ representation is largely a superset +of the representation used in the C front end. There is only one +construct used in C that does not appear in the C++ front end and that +is the GNU ``nested function'' extension. Many of the macros documented +here do not apply in C because the corresponding language constructs do +not appear in C@. + +If you are developing a ``back end'', be it is a code-generator or some +other tool, that uses this representation, you may occasionally find +that you need to ask questions not easily answered by the functions and +macros available here. If that situation occurs, it is quite likely +that GCC already supports the functionality you desire, but that the +interface is simply not documented here. In that case, you should ask +the GCC maintainers (via mail to @email{gcc@@gcc.gnu.org}) about +documenting the functionality you require. Similarly, if you find +yourself writing functions that do not deal directly with your back end, +but instead might be useful to other people using the GCC front end, you +should submit your patches for inclusion in GCC@. + +@menu +* Deficiencies:: Topics net yet covered in this document. +* Tree overview:: All about @code{tree}s. +* Types:: Fundamental and aggregate types. +* Scopes:: Namespaces and classes. +* Functions:: Overloading, function bodies, and linkage. +* Declarations:: Type declarations and variables. +* Attributes:: Declaration and type attributes. +* Expression trees:: From @code{typeid} to @code{throw}. +@end menu + +@c --------------------------------------------------------------------- +@c Deficiencies +@c --------------------------------------------------------------------- + +@node Deficiencies +@section Deficiencies + +There are many places in which this document is incomplet and incorrekt. +It is, as of yet, only @emph{preliminary} documentation. + +@c --------------------------------------------------------------------- +@c Overview +@c --------------------------------------------------------------------- + +@node Tree overview +@section Overview +@cindex tree +@findex TREE_CODE + +The central data structure used by the internal representation is the +@code{tree}. These nodes, while all of the C type @code{tree}, are of +many varieties. A @code{tree} is a pointer type, but the object to +which it points may be of a variety of types. From this point forward, +we will refer to trees in ordinary type, rather than in @code{this +font}, except when talking about the actual C type @code{tree}. + +You can tell what kind of node a particular tree is by using the +@code{TREE_CODE} macro. Many, many macros take trees as input and +return trees as output. However, most macros require a certain kind of +tree node as input. In other words, there is a type-system for trees, +but it is not reflected in the C type-system. + +For safety, it is useful to configure GCC with @option{--enable-checking}. +Although this results in a significant performance penalty (since all +tree types are checked at run-time), and is therefore inappropriate in a +release version, it is extremely helpful during the development process. + +Many macros behave as predicates. Many, although not all, of these +predicates end in @samp{_P}. Do not rely on the result type of these +macros being of any particular type. You may, however, rely on the fact +that the type can be compared to @code{0}, so that statements like +@smallexample +if (TEST_P (t) && !TEST_P (y)) + x = 1; +@end smallexample +@noindent +and +@smallexample +int i = (TEST_P (t) != 0); +@end smallexample +@noindent +are legal. Macros that return @code{int} values now may be changed to +return @code{tree} values, or other pointers in the future. Even those +that continue to return @code{int} may return multiple nonzero codes +where previously they returned only zero and one. Therefore, you should +not write code like +@smallexample +if (TEST_P (t) == 1) +@end smallexample +@noindent +as this code is not guaranteed to work correctly in the future. + +You should not take the address of values returned by the macros or +functions described here. In particular, no guarantee is given that the +values are lvalues. + +In general, the names of macros are all in uppercase, while the names of +functions are entirely in lowercase. There are rare exceptions to this +rule. You should assume that any macro or function whose name is made +up entirely of uppercase letters may evaluate its arguments more than +once. You may assume that a macro or function whose name is made up +entirely of lowercase letters will evaluate its arguments only once. + +The @code{error_mark_node} is a special tree. Its tree code is +@code{ERROR_MARK}, but since there is only ever one node with that code, +the usual practice is to compare the tree against +@code{error_mark_node}. (This test is just a test for pointer +equality.) If an error has occurred during front-end processing the +flag @code{errorcount} will be set. If the front end has encountered +code it cannot handle, it will issue a message to the user and set +@code{sorrycount}. When these flags are set, any macro or function +which normally returns a tree of a particular kind may instead return +the @code{error_mark_node}. Thus, if you intend to do any processing of +erroneous code, you must be prepared to deal with the +@code{error_mark_node}. + +Occasionally, a particular tree slot (like an operand to an expression, +or a particular field in a declaration) will be referred to as +``reserved for the back end''. These slots are used to store RTL when +the tree is converted to RTL for use by the GCC back end. However, if +that process is not taking place (e.g., if the front end is being hooked +up to an intelligent editor), then those slots may be used by the +back end presently in use. + +If you encounter situations that do not match this documentation, such +as tree nodes of types not mentioned here, or macros documented to +return entities of a particular kind that instead return entities of +some different kind, you have found a bug, either in the front end or in +the documentation. Please report these bugs as you would any other +bug. + +@menu +* Macros and Functions::Macros and functions that can be used with all trees. +* Identifiers:: The names of things. +* Containers:: Lists and vectors. +@end menu + +@c --------------------------------------------------------------------- +@c Trees +@c --------------------------------------------------------------------- + +@node Macros and Functions +@subsection Trees +@cindex tree + +This section is not here yet. + +@c --------------------------------------------------------------------- +@c Identifiers +@c --------------------------------------------------------------------- + +@node Identifiers +@subsection Identifiers +@cindex identifier +@cindex name +@tindex IDENTIFIER_NODE + +An @code{IDENTIFIER_NODE} represents a slightly more general concept +that the standard C or C++ concept of identifier. In particular, an +@code{IDENTIFIER_NODE} may contain a @samp{$}, or other extraordinary +characters. + +There are never two distinct @code{IDENTIFIER_NODE}s representing the +same identifier. Therefore, you may use pointer equality to compare +@code{IDENTIFIER_NODE}s, rather than using a routine like @code{strcmp}. + +You can use the following macros to access identifiers: +@ftable @code +@item IDENTIFIER_POINTER +The string represented by the identifier, represented as a +@code{char*}. This string is always @code{NUL}-terminated, and contains +no embedded @code{NUL} characters. + +@item IDENTIFIER_LENGTH +The length of the string returned by @code{IDENTIFIER_POINTER}, not +including the trailing @code{NUL}. This value of +@code{IDENTIFIER_LENGTH (x)} is always the same as @code{strlen +(IDENTIFIER_POINTER (x))}. + +@item IDENTIFIER_OPNAME_P +This predicate holds if the identifier represents the name of an +overloaded operator. In this case, you should not depend on the +contents of either the @code{IDENTIFIER_POINTER} or the +@code{IDENTIFIER_LENGTH}. + +@item IDENTIFIER_TYPENAME_P +This predicate holds if the identifier represents the name of a +user-defined conversion operator. In this case, the @code{TREE_TYPE} of +the @code{IDENTIFIER_NODE} holds the type to which the conversion +operator converts. + +@end ftable + +@c --------------------------------------------------------------------- +@c Containers +@c --------------------------------------------------------------------- + +@node Containers +@subsection Containers +@cindex container +@cindex list +@cindex vector +@tindex TREE_LIST +@tindex TREE_VEC +@findex TREE_PURPOSE +@findex TREE_VALUE +@findex TREE_VEC_LENGTH +@findex TREE_VEC_ELT + +Two common container data structures can be represented directly with +tree nodes. A @code{TREE_LIST} is a singly linked list containing two +trees per node. These are the @code{TREE_PURPOSE} and @code{TREE_VALUE} +of each node. (Often, the @code{TREE_PURPOSE} contains some kind of +tag, or additional information, while the @code{TREE_VALUE} contains the +majority of the payload. In other cases, the @code{TREE_PURPOSE} is +simply @code{NULL_TREE}, while in still others both the +@code{TREE_PURPOSE} and @code{TREE_VALUE} are of equal stature.) Given +one @code{TREE_LIST} node, the next node is found by following the +@code{TREE_CHAIN}. If the @code{TREE_CHAIN} is @code{NULL_TREE}, then +you have reached the end of the list. + +A @code{TREE_VEC} is a simple vector. The @code{TREE_VEC_LENGTH} is an +integer (not a tree) giving the number of nodes in the vector. The +nodes themselves are accessed using the @code{TREE_VEC_ELT} macro, which +takes two arguments. The first is the @code{TREE_VEC} in question; the +second is an integer indicating which element in the vector is desired. +The elements are indexed from zero. + +@c --------------------------------------------------------------------- +@c Types +@c --------------------------------------------------------------------- + +@node Types +@section Types +@cindex type +@cindex pointer +@cindex reference +@cindex fundamental type +@cindex array +@tindex VOID_TYPE +@tindex INTEGER_TYPE +@tindex TYPE_MIN_VALUE +@tindex TYPE_MAX_VALUE +@tindex REAL_TYPE +@tindex COMPLEX_TYPE +@tindex ENUMERAL_TYPE +@tindex BOOLEAN_TYPE +@tindex POINTER_TYPE +@tindex REFERENCE_TYPE +@tindex FUNCTION_TYPE +@tindex METHOD_TYPE +@tindex ARRAY_TYPE +@tindex RECORD_TYPE +@tindex UNION_TYPE +@tindex UNKNOWN_TYPE +@tindex OFFSET_TYPE +@tindex TYPENAME_TYPE +@tindex TYPEOF_TYPE +@findex CP_TYPE_QUALS +@findex TYPE_UNQUALIFIED +@findex TYPE_QUAL_CONST +@findex TYPE_QUAL_VOLATILE +@findex TYPE_QUAL_RESTRICT +@findex TYPE_MAIN_VARIANT +@cindex qualified type +@findex TYPE_SIZE +@findex TYPE_ALIGN +@findex TYPE_PRECISION +@findex TYPE_ARG_TYPES +@findex TYPE_METHOD_BASETYPE +@findex TYPE_PTRMEM_P +@findex TYPE_OFFSET_BASETYPE +@findex TREE_TYPE +@findex TYPE_CONTEXT +@findex TYPE_NAME +@findex TYPENAME_TYPE_FULLNAME +@findex TYPE_FIELDS +@findex TYPE_PTROBV_P + +All types have corresponding tree nodes. However, you should not assume +that there is exactly one tree node corresponding to each type. There +are often several nodes each of which correspond to the same type. + +For the most part, different kinds of types have different tree codes. +(For example, pointer types use a @code{POINTER_TYPE} code while arrays +use an @code{ARRAY_TYPE} code.) However, pointers to member functions +use the @code{RECORD_TYPE} code. Therefore, when writing a +@code{switch} statement that depends on the code associated with a +particular type, you should take care to handle pointers to member +functions under the @code{RECORD_TYPE} case label. + +In C++, an array type is not qualified; rather the type of the array +elements is qualified. This situation is reflected in the intermediate +representation. The macros described here will always examine the +qualification of the underlying element type when applied to an array +type. (If the element type is itself an array, then the recursion +continues until a non-array type is found, and the qualification of this +type is examined.) So, for example, @code{CP_TYPE_CONST_P} will hold of +the type @code{const int ()[7]}, denoting an array of seven @code{int}s. + +The following functions and macros deal with cv-qualification of types: +@ftable @code +@item CP_TYPE_QUALS +This macro returns the set of type qualifiers applied to this type. +This value is @code{TYPE_UNQUALIFIED} if no qualifiers have been +applied. The @code{TYPE_QUAL_CONST} bit is set if the type is +@code{const}-qualified. The @code{TYPE_QUAL_VOLATILE} bit is set if the +type is @code{volatile}-qualified. The @code{TYPE_QUAL_RESTRICT} bit is +set if the type is @code{restrict}-qualified. + +@item CP_TYPE_CONST_P +This macro holds if the type is @code{const}-qualified. + +@item CP_TYPE_VOLATILE_P +This macro holds if the type is @code{volatile}-qualified. + +@item CP_TYPE_RESTRICT_P +This macro holds if the type is @code{restrict}-qualified. + +@item CP_TYPE_CONST_NON_VOLATILE_P +This predicate holds for a type that is @code{const}-qualified, but +@emph{not} @code{volatile}-qualified; other cv-qualifiers are ignored as +well: only the @code{const}-ness is tested. + +@item TYPE_MAIN_VARIANT +This macro returns the unqualified version of a type. It may be applied +to an unqualified type, but it is not always the identity function in +that case. +@end ftable + +A few other macros and functions are usable with all types: +@ftable @code +@item TYPE_SIZE +The number of bits required to represent the type, represented as an +@code{INTEGER_CST}. For an incomplete type, @code{TYPE_SIZE} will be +@code{NULL_TREE}. + +@item TYPE_ALIGN +The alignment of the type, in bits, represented as an @code{int}. + +@item TYPE_NAME +This macro returns a declaration (in the form of a @code{TYPE_DECL}) for +the type. (Note this macro does @emph{not} return a +@code{IDENTIFIER_NODE}, as you might expect, given its name!) You can +look at the @code{DECL_NAME} of the @code{TYPE_DECL} to obtain the +actual name of the type. The @code{TYPE_NAME} will be @code{NULL_TREE} +for a type that is not a built-in type, the result of a typedef, or a +named class type. + +@item CP_INTEGRAL_TYPE +This predicate holds if the type is an integral type. Notice that in +C++, enumerations are @emph{not} integral types. + +@item ARITHMETIC_TYPE_P +This predicate holds if the type is an integral type (in the C++ sense) +or a floating point type. + +@item CLASS_TYPE_P +This predicate holds for a class-type. + +@item TYPE_BUILT_IN +This predicate holds for a built-in type. + +@item TYPE_PTRMEM_P +This predicate holds if the type is a pointer to data member. + +@item TYPE_PTR_P +This predicate holds if the type is a pointer type, and the pointee is +not a data member. + +@item TYPE_PTRFN_P +This predicate holds for a pointer to function type. + +@item TYPE_PTROB_P +This predicate holds for a pointer to object type. Note however that it +does not hold for the generic pointer to object type @code{void *}. You +may use @code{TYPE_PTROBV_P} to test for a pointer to object type as +well as @code{void *}. + +@item same_type_p +This predicate takes two types as input, and holds if they are the same +type. For example, if one type is a @code{typedef} for the other, or +both are @code{typedef}s for the same type. This predicate also holds if +the two trees given as input are simply copies of one another; i.e., +there is no difference between them at the source level, but, for +whatever reason, a duplicate has been made in the representation. You +should never use @code{==} (pointer equality) to compare types; always +use @code{same_type_p} instead. +@end ftable + +Detailed below are the various kinds of types, and the macros that can +be used to access them. Although other kinds of types are used +elsewhere in G++, the types described here are the only ones that you +will encounter while examining the intermediate representation. + +@table @code +@item VOID_TYPE +Used to represent the @code{void} type. + +@item INTEGER_TYPE +Used to represent the various integral types, including @code{char}, +@code{short}, @code{int}, @code{long}, and @code{long long}. This code +is not used for enumeration types, nor for the @code{bool} type. +The @code{TYPE_PRECISION} is the number of bits used in +the representation, represented as an @code{unsigned int}. (Note that +in the general case this is not the same value as @code{TYPE_SIZE}; +suppose that there were a 24-bit integer type, but that alignment +requirements for the ABI required 32-bit alignment. Then, +@code{TYPE_SIZE} would be an @code{INTEGER_CST} for 32, while +@code{TYPE_PRECISION} would be 24.) The integer type is unsigned if +@code{TYPE_UNSIGNED} holds; otherwise, it is signed. + +The @code{TYPE_MIN_VALUE} is an @code{INTEGER_CST} for the smallest +integer that may be represented by this type. Similarly, the +@code{TYPE_MAX_VALUE} is an @code{INTEGER_CST} for the largest integer +that may be represented by this type. + +@item REAL_TYPE +Used to represent the @code{float}, @code{double}, and @code{long +double} types. The number of bits in the floating-point representation +is given by @code{TYPE_PRECISION}, as in the @code{INTEGER_TYPE} case. + +@item COMPLEX_TYPE +Used to represent GCC built-in @code{__complex__} data types. The +@code{TREE_TYPE} is the type of the real and imaginary parts. + +@item ENUMERAL_TYPE +Used to represent an enumeration type. The @code{TYPE_PRECISION} gives +(as an @code{int}), the number of bits used to represent the type. If +there are no negative enumeration constants, @code{TYPE_UNSIGNED} will +hold. The minimum and maximum enumeration constants may be obtained +with @code{TYPE_MIN_VALUE} and @code{TYPE_MAX_VALUE}, respectively; each +of these macros returns an @code{INTEGER_CST}. + +The actual enumeration constants themselves may be obtained by looking +at the @code{TYPE_VALUES}. This macro will return a @code{TREE_LIST}, +containing the constants. The @code{TREE_PURPOSE} of each node will be +an @code{IDENTIFIER_NODE} giving the name of the constant; the +@code{TREE_VALUE} will be an @code{INTEGER_CST} giving the value +assigned to that constant. These constants will appear in the order in +which they were declared. The @code{TREE_TYPE} of each of these +constants will be the type of enumeration type itself. + +@item BOOLEAN_TYPE +Used to represent the @code{bool} type. + +@item POINTER_TYPE +Used to represent pointer types, and pointer to data member types. The +@code{TREE_TYPE} gives the type to which this type points. If the type +is a pointer to data member type, then @code{TYPE_PTRMEM_P} will hold. +For a pointer to data member type of the form @samp{T X::*}, +@code{TYPE_PTRMEM_CLASS_TYPE} will be the type @code{X}, while +@code{TYPE_PTRMEM_POINTED_TO_TYPE} will be the type @code{T}. + +@item REFERENCE_TYPE +Used to represent reference types. The @code{TREE_TYPE} gives the type +to which this type refers. + +@item FUNCTION_TYPE +Used to represent the type of non-member functions and of static member +functions. The @code{TREE_TYPE} gives the return type of the function. +The @code{TYPE_ARG_TYPES} are a @code{TREE_LIST} of the argument types. +The @code{TREE_VALUE} of each node in this list is the type of the +corresponding argument; the @code{TREE_PURPOSE} is an expression for the +default argument value, if any. If the last node in the list is +@code{void_list_node} (a @code{TREE_LIST} node whose @code{TREE_VALUE} +is the @code{void_type_node}), then functions of this type do not take +variable arguments. Otherwise, they do take a variable number of +arguments. + +Note that in C (but not in C++) a function declared like @code{void f()} +is an unprototyped function taking a variable number of arguments; the +@code{TYPE_ARG_TYPES} of such a function will be @code{NULL}. + +@item METHOD_TYPE +Used to represent the type of a non-static member function. Like a +@code{FUNCTION_TYPE}, the return type is given by the @code{TREE_TYPE}. +The type of @code{*this}, i.e., the class of which functions of this +type are a member, is given by the @code{TYPE_METHOD_BASETYPE}. The +@code{TYPE_ARG_TYPES} is the parameter list, as for a +@code{FUNCTION_TYPE}, and includes the @code{this} argument. + +@item ARRAY_TYPE +Used to represent array types. The @code{TREE_TYPE} gives the type of +the elements in the array. If the array-bound is present in the type, +the @code{TYPE_DOMAIN} is an @code{INTEGER_TYPE} whose +@code{TYPE_MIN_VALUE} and @code{TYPE_MAX_VALUE} will be the lower and +upper bounds of the array, respectively. The @code{TYPE_MIN_VALUE} will +always be an @code{INTEGER_CST} for zero, while the +@code{TYPE_MAX_VALUE} will be one less than the number of elements in +the array, i.e., the highest value which may be used to index an element +in the array. + +@item RECORD_TYPE +Used to represent @code{struct} and @code{class} types, as well as +pointers to member functions and similar constructs in other languages. +@code{TYPE_FIELDS} contains the items contained in this type, each of +which can be a @code{FIELD_DECL}, @code{VAR_DECL}, @code{CONST_DECL}, or +@code{TYPE_DECL}. You may not make any assumptions about the ordering +of the fields in the type or whether one or more of them overlap. If +@code{TYPE_PTRMEMFUNC_P} holds, then this type is a pointer-to-member +type. In that case, the @code{TYPE_PTRMEMFUNC_FN_TYPE} is a +@code{POINTER_TYPE} pointing to a @code{METHOD_TYPE}. The +@code{METHOD_TYPE} is the type of a function pointed to by the +pointer-to-member function. If @code{TYPE_PTRMEMFUNC_P} does not hold, +this type is a class type. For more information, see @pxref{Classes}. + +@item UNION_TYPE +Used to represent @code{union} types. Similar to @code{RECORD_TYPE} +except that all @code{FIELD_DECL} nodes in @code{TYPE_FIELD} start at +bit position zero. + +@item QUAL_UNION_TYPE +Used to represent part of a variant record in Ada. Similar to +@code{UNION_TYPE} except that each @code{FIELD_DECL} has a +@code{DECL_QUALIFIER} field, which contains a boolean expression that +indicates whether the field is present in the object. The type will only +have one field, so each field's @code{DECL_QUALIFIER} is only evaluated +if none of the expressions in the previous fields in @code{TYPE_FIELDS} +are nonzero. Normally these expressions will reference a field in the +outer object using a @code{PLACEHOLDER_EXPR}. + +@item UNKNOWN_TYPE +This node is used to represent a type the knowledge of which is +insufficient for a sound processing. + +@item OFFSET_TYPE +This node is used to represent a pointer-to-data member. For a data +member @code{X::m} the @code{TYPE_OFFSET_BASETYPE} is @code{X} and the +@code{TREE_TYPE} is the type of @code{m}. + +@item TYPENAME_TYPE +Used to represent a construct of the form @code{typename T::A}. The +@code{TYPE_CONTEXT} is @code{T}; the @code{TYPE_NAME} is an +@code{IDENTIFIER_NODE} for @code{A}. If the type is specified via a +template-id, then @code{TYPENAME_TYPE_FULLNAME} yields a +@code{TEMPLATE_ID_EXPR}. The @code{TREE_TYPE} is non-@code{NULL} if the +node is implicitly generated in support for the implicit typename +extension; in which case the @code{TREE_TYPE} is a type node for the +base-class. + +@item TYPEOF_TYPE +Used to represent the @code{__typeof__} extension. The +@code{TYPE_FIELDS} is the expression the type of which is being +represented. +@end table + +There are variables whose values represent some of the basic types. +These include: +@table @code +@item void_type_node +A node for @code{void}. + +@item integer_type_node +A node for @code{int}. + +@item unsigned_type_node. +A node for @code{unsigned int}. + +@item char_type_node. +A node for @code{char}. +@end table +@noindent +It may sometimes be useful to compare one of these variables with a type +in hand, using @code{same_type_p}. + +@c --------------------------------------------------------------------- +@c Scopes +@c --------------------------------------------------------------------- + +@node Scopes +@section Scopes +@cindex namespace, class, scope + +The root of the entire intermediate representation is the variable +@code{global_namespace}. This is the namespace specified with @code{::} +in C++ source code. All other namespaces, types, variables, functions, +and so forth can be found starting with this namespace. + +Besides namespaces, the other high-level scoping construct in C++ is the +class. (Throughout this manual the term @dfn{class} is used to mean the +types referred to in the ANSI/ISO C++ Standard as classes; these include +types defined with the @code{class}, @code{struct}, and @code{union} +keywords.) + +@menu +* Namespaces:: Member functions, types, etc. +* Classes:: Members, bases, friends, etc. +@end menu + +@c --------------------------------------------------------------------- +@c Namespaces +@c --------------------------------------------------------------------- + +@node Namespaces +@subsection Namespaces +@cindex namespace +@tindex NAMESPACE_DECL + +A namespace is represented by a @code{NAMESPACE_DECL} node. + +However, except for the fact that it is distinguished as the root of the +representation, the global namespace is no different from any other +namespace. Thus, in what follows, we describe namespaces generally, +rather than the global namespace in particular. + +The following macros and functions can be used on a @code{NAMESPACE_DECL}: + +@ftable @code +@item DECL_NAME +This macro is used to obtain the @code{IDENTIFIER_NODE} corresponding to +the unqualified name of the name of the namespace (@pxref{Identifiers}). +The name of the global namespace is @samp{::}, even though in C++ the +global namespace is unnamed. However, you should use comparison with +@code{global_namespace}, rather than @code{DECL_NAME} to determine +whether or not a namespace is the global one. An unnamed namespace +will have a @code{DECL_NAME} equal to @code{anonymous_namespace_name}. +Within a single translation unit, all unnamed namespaces will have the +same name. + +@item DECL_CONTEXT +This macro returns the enclosing namespace. The @code{DECL_CONTEXT} for +the @code{global_namespace} is @code{NULL_TREE}. + +@item DECL_NAMESPACE_ALIAS +If this declaration is for a namespace alias, then +@code{DECL_NAMESPACE_ALIAS} is the namespace for which this one is an +alias. + +Do not attempt to use @code{cp_namespace_decls} for a namespace which is +an alias. Instead, follow @code{DECL_NAMESPACE_ALIAS} links until you +reach an ordinary, non-alias, namespace, and call +@code{cp_namespace_decls} there. + +@item DECL_NAMESPACE_STD_P +This predicate holds if the namespace is the special @code{::std} +namespace. + +@item cp_namespace_decls +This function will return the declarations contained in the namespace, +including types, overloaded functions, other namespaces, and so forth. +If there are no declarations, this function will return +@code{NULL_TREE}. The declarations are connected through their +@code{TREE_CHAIN} fields. + +Although most entries on this list will be declarations, +@code{TREE_LIST} nodes may also appear. In this case, the +@code{TREE_VALUE} will be an @code{OVERLOAD}. The value of the +@code{TREE_PURPOSE} is unspecified; back ends should ignore this value. +As with the other kinds of declarations returned by +@code{cp_namespace_decls}, the @code{TREE_CHAIN} will point to the next +declaration in this list. + +For more information on the kinds of declarations that can occur on this +list, @xref{Declarations}. Some declarations will not appear on this +list. In particular, no @code{FIELD_DECL}, @code{LABEL_DECL}, or +@code{PARM_DECL} nodes will appear here. + +This function cannot be used with namespaces that have +@code{DECL_NAMESPACE_ALIAS} set. + +@end ftable + +@c --------------------------------------------------------------------- +@c Classes +@c --------------------------------------------------------------------- + +@node Classes +@subsection Classes +@cindex class +@tindex RECORD_TYPE +@tindex UNION_TYPE +@findex CLASSTYPE_DECLARED_CLASS +@findex TYPE_BINFO +@findex BINFO_TYPE +@findex TYPE_FIELDS +@findex TYPE_VFIELD +@findex TYPE_METHODS + +A class type is represented by either a @code{RECORD_TYPE} or a +@code{UNION_TYPE}. A class declared with the @code{union} tag is +represented by a @code{UNION_TYPE}, while classes declared with either +the @code{struct} or the @code{class} tag are represented by +@code{RECORD_TYPE}s. You can use the @code{CLASSTYPE_DECLARED_CLASS} +macro to discern whether or not a particular type is a @code{class} as +opposed to a @code{struct}. This macro will be true only for classes +declared with the @code{class} tag. + +Almost all non-function members are available on the @code{TYPE_FIELDS} +list. Given one member, the next can be found by following the +@code{TREE_CHAIN}. You should not depend in any way on the order in +which fields appear on this list. All nodes on this list will be +@samp{DECL} nodes. A @code{FIELD_DECL} is used to represent a non-static +data member, a @code{VAR_DECL} is used to represent a static data +member, and a @code{TYPE_DECL} is used to represent a type. Note that +the @code{CONST_DECL} for an enumeration constant will appear on this +list, if the enumeration type was declared in the class. (Of course, +the @code{TYPE_DECL} for the enumeration type will appear here as well.) +There are no entries for base classes on this list. In particular, +there is no @code{FIELD_DECL} for the ``base-class portion'' of an +object. + +The @code{TYPE_VFIELD} is a compiler-generated field used to point to +virtual function tables. It may or may not appear on the +@code{TYPE_FIELDS} list. However, back ends should handle the +@code{TYPE_VFIELD} just like all the entries on the @code{TYPE_FIELDS} +list. + +The function members are available on the @code{TYPE_METHODS} list. +Again, subsequent members are found by following the @code{TREE_CHAIN} +field. If a function is overloaded, each of the overloaded functions +appears; no @code{OVERLOAD} nodes appear on the @code{TYPE_METHODS} +list. Implicitly declared functions (including default constructors, +copy constructors, assignment operators, and destructors) will appear on +this list as well. + +Every class has an associated @dfn{binfo}, which can be obtained with +@code{TYPE_BINFO}. Binfos are used to represent base-classes. The +binfo given by @code{TYPE_BINFO} is the degenerate case, whereby every +class is considered to be its own base-class. The base binfos for a +particular binfo are held in a vector, whose length is obtained with +@code{BINFO_N_BASE_BINFOS}. The base binfos themselves are obtained +with @code{BINFO_BASE_BINFO} and @code{BINFO_BASE_ITERATE}. To add a +new binfo, use @code{BINFO_BASE_APPEND}. The vector of base binfos can +be obtained with @code{BINFO_BASE_BINFOS}, but normally you do not need +to use that. The class type associated with a binfo is given by +@code{BINFO_TYPE}. It is not always the case that @code{BINFO_TYPE +(TYPE_BINFO (x))}, because of typedefs and qualified types. Neither is +it the case that @code{TYPE_BINFO (BINFO_TYPE (y))} is the same binfo as +@code{y}. The reason is that if @code{y} is a binfo representing a +base-class @code{B} of a derived class @code{D}, then @code{BINFO_TYPE +(y)} will be @code{B}, and @code{TYPE_BINFO (BINFO_TYPE (y))} will be +@code{B} as its own base-class, rather than as a base-class of @code{D}. + +The access to a base type can be found with @code{BINFO_BASE_ACCESS}. +This will produce @code{access_public_node}, @code{access_private_node} +or @code{access_protected_node}. If bases are always public, +@code{BINFO_BASE_ACCESSES} may be @code{NULL}. + +@code{BINFO_VIRTUAL_P} is used to specify whether the binfo is inherited +virtually or not. The other flags, @code{BINFO_MARKED_P} and +@code{BINFO_FLAG_1} to @code{BINFO_FLAG_6} can be used for language +specific use. + +The following macros can be used on a tree node representing a class-type. + +@ftable @code +@item LOCAL_CLASS_P +This predicate holds if the class is local class @emph{i.e.}@: declared +inside a function body. + +@item TYPE_POLYMORPHIC_P +This predicate holds if the class has at least one virtual function +(declared or inherited). + +@item TYPE_HAS_DEFAULT_CONSTRUCTOR +This predicate holds whenever its argument represents a class-type with +default constructor. + +@item CLASSTYPE_HAS_MUTABLE +@itemx TYPE_HAS_MUTABLE_P +These predicates hold for a class-type having a mutable data member. + +@item CLASSTYPE_NON_POD_P +This predicate holds only for class-types that are not PODs. + +@item TYPE_HAS_NEW_OPERATOR +This predicate holds for a class-type that defines +@code{operator new}. + +@item TYPE_HAS_ARRAY_NEW_OPERATOR +This predicate holds for a class-type for which +@code{operator new[]} is defined. + +@item TYPE_OVERLOADS_CALL_EXPR +This predicate holds for class-type for which the function call +@code{operator()} is overloaded. + +@item TYPE_OVERLOADS_ARRAY_REF +This predicate holds for a class-type that overloads +@code{operator[]} + +@item TYPE_OVERLOADS_ARROW +This predicate holds for a class-type for which @code{operator->} is +overloaded. + +@end ftable + +@c --------------------------------------------------------------------- +@c Declarations +@c --------------------------------------------------------------------- + +@node Declarations +@section Declarations +@cindex declaration +@cindex variable +@cindex type declaration +@tindex LABEL_DECL +@tindex CONST_DECL +@tindex TYPE_DECL +@tindex VAR_DECL +@tindex PARM_DECL +@tindex FIELD_DECL +@tindex NAMESPACE_DECL +@tindex RESULT_DECL +@tindex TEMPLATE_DECL +@tindex THUNK_DECL +@tindex USING_DECL +@findex THUNK_DELTA +@findex DECL_INITIAL +@findex DECL_SIZE +@findex DECL_ALIGN +@findex DECL_EXTERNAL + +This section covers the various kinds of declarations that appear in the +internal representation, except for declarations of functions +(represented by @code{FUNCTION_DECL} nodes), which are described in +@ref{Functions}. + +@menu +* Working with declarations:: Macros and functions that work on +declarations. +* Internal structure:: How declaration nodes are represented. +@end menu + +@node Working with declarations +@subsection Working with declarations + +Some macros can be used with any kind of declaration. These include: +@ftable @code +@item DECL_NAME +This macro returns an @code{IDENTIFIER_NODE} giving the name of the +entity. + +@item TREE_TYPE +This macro returns the type of the entity declared. + +@item TREE_FILENAME +This macro returns the name of the file in which the entity was +declared, as a @code{char*}. For an entity declared implicitly by the +compiler (like @code{__builtin_memcpy}), this will be the string +@code{"<internal>"}. + +@item TREE_LINENO +This macro returns the line number at which the entity was declared, as +an @code{int}. + +@item DECL_ARTIFICIAL +This predicate holds if the declaration was implicitly generated by the +compiler. For example, this predicate will hold of an implicitly +declared member function, or of the @code{TYPE_DECL} implicitly +generated for a class type. Recall that in C++ code like: +@smallexample +struct S @{@}; +@end smallexample +@noindent +is roughly equivalent to C code like: +@smallexample +struct S @{@}; +typedef struct S S; +@end smallexample +The implicitly generated @code{typedef} declaration is represented by a +@code{TYPE_DECL} for which @code{DECL_ARTIFICIAL} holds. + +@item DECL_NAMESPACE_SCOPE_P +This predicate holds if the entity was declared at a namespace scope. + +@item DECL_CLASS_SCOPE_P +This predicate holds if the entity was declared at a class scope. + +@item DECL_FUNCTION_SCOPE_P +This predicate holds if the entity was declared inside a function +body. + +@end ftable + +The various kinds of declarations include: +@table @code +@item LABEL_DECL +These nodes are used to represent labels in function bodies. For more +information, see @ref{Functions}. These nodes only appear in block +scopes. + +@item CONST_DECL +These nodes are used to represent enumeration constants. The value of +the constant is given by @code{DECL_INITIAL} which will be an +@code{INTEGER_CST} with the same type as the @code{TREE_TYPE} of the +@code{CONST_DECL}, i.e., an @code{ENUMERAL_TYPE}. + +@item RESULT_DECL +These nodes represent the value returned by a function. When a value is +assigned to a @code{RESULT_DECL}, that indicates that the value should +be returned, via bitwise copy, by the function. You can use +@code{DECL_SIZE} and @code{DECL_ALIGN} on a @code{RESULT_DECL}, just as +with a @code{VAR_DECL}. + +@item TYPE_DECL +These nodes represent @code{typedef} declarations. The @code{TREE_TYPE} +is the type declared to have the name given by @code{DECL_NAME}. In +some cases, there is no associated name. + +@item VAR_DECL +These nodes represent variables with namespace or block scope, as well +as static data members. The @code{DECL_SIZE} and @code{DECL_ALIGN} are +analogous to @code{TYPE_SIZE} and @code{TYPE_ALIGN}. For a declaration, +you should always use the @code{DECL_SIZE} and @code{DECL_ALIGN} rather +than the @code{TYPE_SIZE} and @code{TYPE_ALIGN} given by the +@code{TREE_TYPE}, since special attributes may have been applied to the +variable to give it a particular size and alignment. You may use the +predicates @code{DECL_THIS_STATIC} or @code{DECL_THIS_EXTERN} to test +whether the storage class specifiers @code{static} or @code{extern} were +used to declare a variable. + +If this variable is initialized (but does not require a constructor), +the @code{DECL_INITIAL} will be an expression for the initializer. The +initializer should be evaluated, and a bitwise copy into the variable +performed. If the @code{DECL_INITIAL} is the @code{error_mark_node}, +there is an initializer, but it is given by an explicit statement later +in the code; no bitwise copy is required. + +GCC provides an extension that allows either automatic variables, or +global variables, to be placed in particular registers. This extension +is being used for a particular @code{VAR_DECL} if @code{DECL_REGISTER} +holds for the @code{VAR_DECL}, and if @code{DECL_ASSEMBLER_NAME} is not +equal to @code{DECL_NAME}. In that case, @code{DECL_ASSEMBLER_NAME} is +the name of the register into which the variable will be placed. + +@item PARM_DECL +Used to represent a parameter to a function. Treat these nodes +similarly to @code{VAR_DECL} nodes. These nodes only appear in the +@code{DECL_ARGUMENTS} for a @code{FUNCTION_DECL}. + +The @code{DECL_ARG_TYPE} for a @code{PARM_DECL} is the type that will +actually be used when a value is passed to this function. It may be a +wider type than the @code{TREE_TYPE} of the parameter; for example, the +ordinary type might be @code{short} while the @code{DECL_ARG_TYPE} is +@code{int}. + +@item FIELD_DECL +These nodes represent non-static data members. The @code{DECL_SIZE} and +@code{DECL_ALIGN} behave as for @code{VAR_DECL} nodes. +The position of the field within the parent record is specified by a +combination of three attributes. @code{DECL_FIELD_OFFSET} is the position, +counting in bytes, of the @code{DECL_OFFSET_ALIGN}-bit sized word containing +the bit of the field closest to the beginning of the structure. +@code{DECL_FIELD_BIT_OFFSET} is the bit offset of the first bit of the field +within this word; this may be nonzero even for fields that are not bit-fields, +since @code{DECL_OFFSET_ALIGN} may be greater than the natural alignment +of the field's type. + +If @code{DECL_C_BIT_FIELD} holds, this field is a bit-field. In a bit-field, +@code{DECL_BIT_FIELD_TYPE} also contains the type that was originally +specified for it, while DECL_TYPE may be a modified type with lesser precision, +according to the size of the bit field. + +@item NAMESPACE_DECL +@xref{Namespaces}. + +@item TEMPLATE_DECL + +These nodes are used to represent class, function, and variable (static +data member) templates. The @code{DECL_TEMPLATE_SPECIALIZATIONS} are a +@code{TREE_LIST}. The @code{TREE_VALUE} of each node in the list is a +@code{TEMPLATE_DECL}s or @code{FUNCTION_DECL}s representing +specializations (including instantiations) of this template. Back ends +can safely ignore @code{TEMPLATE_DECL}s, but should examine +@code{FUNCTION_DECL} nodes on the specializations list just as they +would ordinary @code{FUNCTION_DECL} nodes. + +For a class template, the @code{DECL_TEMPLATE_INSTANTIATIONS} list +contains the instantiations. The @code{TREE_VALUE} of each node is an +instantiation of the class. The @code{DECL_TEMPLATE_SPECIALIZATIONS} +contains partial specializations of the class. + +@item USING_DECL + +Back ends can safely ignore these nodes. + +@end table + +@node Internal structure +@subsection Internal structure + +@code{DECL} nodes are represented internally as a hierarchy of +structures. + +@menu +* Current structure hierarchy:: The current DECL node structure +hierarchy. +* Adding new DECL node types:: How to add a new DECL node to a +frontend. +@end menu + +@node Current structure hierarchy +@subsubsection Current structure hierarchy + +@table @code + +@item struct tree_decl_minimal +This is the minimal structure to inherit from in order for common +@code{DECL} macros to work. The fields it contains are a unique ID, +source location, context, and name. + +@item struct tree_decl_common +This structure inherits from @code{struct tree_decl_minimal}. It +contains fields that most @code{DECL} nodes need, such as a field to +store alignment, machine mode, size, and attributes. + +@item struct tree_field_decl +This structure inherits from @code{struct tree_decl_common}. It is +used to represent @code{FIELD_DECL}. + +@item struct tree_label_decl +This structure inherits from @code{struct tree_decl_common}. It is +used to represent @code{LABEL_DECL}. + +@item struct tree_translation_unit_decl +This structure inherits from @code{struct tree_decl_common}. It is +used to represent @code{TRANSLATION_UNIT_DECL}. + +@item struct tree_decl_with_rtl +This structure inherits from @code{struct tree_decl_common}. It +contains a field to store the low-level RTL associated with a +@code{DECL} node. + +@item struct tree_result_decl +This structure inherits from @code{struct tree_decl_with_rtl}. It is +used to represent @code{RESULT_DECL}. + +@item struct tree_const_decl +This structure inherits from @code{struct tree_decl_with_rtl}. It is +used to represent @code{CONST_DECL}. + +@item struct tree_parm_decl +This structure inherits from @code{struct tree_decl_with_rtl}. It is +used to represent @code{PARM_DECL}. + +@item struct tree_decl_with_vis +This structure inherits from @code{struct tree_decl_with_rtl}. It +contains fields necessary to store visibility information, as well as +a section name and assembler name. + +@item struct tree_var_decl +This structure inherits from @code{struct tree_decl_with_vis}. It is +used to represent @code{VAR_DECL}. + +@item struct tree_function_decl +This structure inherits from @code{struct tree_decl_with_vis}. It is +used to represent @code{FUNCTION_DECL}. + +@end table +@node Adding new DECL node types +@subsubsection Adding new DECL node types + +Adding a new @code{DECL} tree consists of the following steps + +@table @asis + +@item Add a new tree code for the @code{DECL} node +For language specific @code{DECL} nodes, there is a @file{.def} file +in each frontend directory where the tree code should be added. +For @code{DECL} nodes that are part of the middle-end, the code should +be added to @file{tree.def}. + +@item Create a new structure type for the @code{DECL} node +These structures should inherit from one of the existing structures in +the language hierarchy by using that structure as the first member. + +@smallexample +struct tree_foo_decl +@{ + struct tree_decl_with_vis common; +@} +@end smallexample + +Would create a structure name @code{tree_foo_decl} that inherits from +@code{struct tree_decl_with_vis}. + +For language specific @code{DECL} nodes, this new structure type +should go in the appropriate @file{.h} file. +For @code{DECL} nodes that are part of the middle-end, the structure +type should go in @file{tree.h}. + +@item Add a member to the tree structure enumerator for the node +For garbage collection and dynamic checking purposes, each @code{DECL} +node structure type is required to have a unique enumerator value +specified with it. +For language specific @code{DECL} nodes, this new enumerator value +should go in the appropriate @file{.def} file. +For @code{DECL} nodes that are part of the middle-end, the enumerator +values are specified in @file{treestruct.def}. + +@item Update @code{union tree_node} +In order to make your new structure type usable, it must be added to +@code{union tree_node}. +For language specific @code{DECL} nodes, a new entry should be added +to the appropriate @file{.h} file of the form +@smallexample + struct tree_foo_decl GTY ((tag ("TS_VAR_DECL"))) foo_decl; +@end smallexample +For @code{DECL} nodes that are part of the middle-end, the additional +member goes directly into @code{union tree_node} in @file{tree.h}. + +@item Update dynamic checking info +In order to be able to check whether accessing a named portion of +@code{union tree_node} is legal, and whether a certain @code{DECL} node +contains one of the enumerated @code{DECL} node structures in the +hierarchy, a simple lookup table is used. +This lookup table needs to be kept up to date with the tree structure +hierarchy, or else checking and containment macros will fail +inappropriately. + +For language specific @code{DECL} nodes, their is an @code{init_ts} +function in an appropriate @file{.c} file, which initializes the lookup +table. +Code setting up the table for new @code{DECL} nodes should be added +there. +For each @code{DECL} tree code and enumerator value representing a +member of the inheritance hierarchy, the table should contain 1 if +that tree code inherits (directly or indirectly) from that member. +Thus, a @code{FOO_DECL} node derived from @code{struct decl_with_rtl}, +and enumerator value @code{TS_FOO_DECL}, would be set up as follows +@smallexample +tree_contains_struct[FOO_DECL][TS_FOO_DECL] = 1; +tree_contains_struct[FOO_DECL][TS_DECL_WRTL] = 1; +tree_contains_struct[FOO_DECL][TS_DECL_COMMON] = 1; +tree_contains_struct[FOO_DECL][TS_DECL_MINIMAL] = 1; +@end smallexample + +For @code{DECL} nodes that are part of the middle-end, the setup code +goes into @file{tree.c}. + +@item Add macros to access any new fields and flags + +Each added field or flag should have a macro that is used to access +it, that performs appropriate checking to ensure only the right type of +@code{DECL} nodes access the field. + +These macros generally take the following form +@smallexample +#define FOO_DECL_FIELDNAME(NODE) FOO_DECL_CHECK(NODE)->foo_decl.fieldname +@end smallexample +However, if the structure is simply a base class for further +structures, something like the following should be used +@smallexample +#define BASE_STRUCT_CHECK(T) CONTAINS_STRUCT_CHECK(T, TS_BASE_STRUCT) +#define BASE_STRUCT_FIELDNAME(NODE) \ + (BASE_STRUCT_CHECK(NODE)->base_struct.fieldname +@end smallexample + +@end table + + +@c --------------------------------------------------------------------- +@c Functions +@c --------------------------------------------------------------------- + +@node Functions +@section Functions +@cindex function +@tindex FUNCTION_DECL +@tindex OVERLOAD +@findex OVL_CURRENT +@findex OVL_NEXT + +A function is represented by a @code{FUNCTION_DECL} node. A set of +overloaded functions is sometimes represented by a @code{OVERLOAD} node. + +An @code{OVERLOAD} node is not a declaration, so none of the +@samp{DECL_} macros should be used on an @code{OVERLOAD}. An +@code{OVERLOAD} node is similar to a @code{TREE_LIST}. Use +@code{OVL_CURRENT} to get the function associated with an +@code{OVERLOAD} node; use @code{OVL_NEXT} to get the next +@code{OVERLOAD} node in the list of overloaded functions. The macros +@code{OVL_CURRENT} and @code{OVL_NEXT} are actually polymorphic; you can +use them to work with @code{FUNCTION_DECL} nodes as well as with +overloads. In the case of a @code{FUNCTION_DECL}, @code{OVL_CURRENT} +will always return the function itself, and @code{OVL_NEXT} will always +be @code{NULL_TREE}. + +To determine the scope of a function, you can use the +@code{DECL_CONTEXT} macro. This macro will return the class +(either a @code{RECORD_TYPE} or a @code{UNION_TYPE}) or namespace (a +@code{NAMESPACE_DECL}) of which the function is a member. For a virtual +function, this macro returns the class in which the function was +actually defined, not the base class in which the virtual declaration +occurred. + +If a friend function is defined in a class scope, the +@code{DECL_FRIEND_CONTEXT} macro can be used to determine the class in +which it was defined. For example, in +@smallexample +class C @{ friend void f() @{@} @}; +@end smallexample +@noindent +the @code{DECL_CONTEXT} for @code{f} will be the +@code{global_namespace}, but the @code{DECL_FRIEND_CONTEXT} will be the +@code{RECORD_TYPE} for @code{C}. + +In C, the @code{DECL_CONTEXT} for a function maybe another function. +This representation indicates that the GNU nested function extension +is in use. For details on the semantics of nested functions, see the +GCC Manual. The nested function can refer to local variables in its +containing function. Such references are not explicitly marked in the +tree structure; back ends must look at the @code{DECL_CONTEXT} for the +referenced @code{VAR_DECL}. If the @code{DECL_CONTEXT} for the +referenced @code{VAR_DECL} is not the same as the function currently +being processed, and neither @code{DECL_EXTERNAL} nor +@code{DECL_STATIC} hold, then the reference is to a local variable in +a containing function, and the back end must take appropriate action. + +@menu +* Function Basics:: Function names, linkage, and so forth. +* Function Bodies:: The statements that make up a function body. +@end menu + +@c --------------------------------------------------------------------- +@c Function Basics +@c --------------------------------------------------------------------- + +@node Function Basics +@subsection Function Basics +@cindex constructor +@cindex destructor +@cindex copy constructor +@cindex assignment operator +@cindex linkage +@findex DECL_NAME +@findex DECL_ASSEMBLER_NAME +@findex TREE_PUBLIC +@findex DECL_LINKONCE_P +@findex DECL_FUNCTION_MEMBER_P +@findex DECL_CONSTRUCTOR_P +@findex DECL_DESTRUCTOR_P +@findex DECL_OVERLOADED_OPERATOR_P +@findex DECL_CONV_FN_P +@findex DECL_ARTIFICIAL +@findex DECL_GLOBAL_CTOR_P +@findex DECL_GLOBAL_DTOR_P +@findex GLOBAL_INIT_PRIORITY + +The following macros and functions can be used on a @code{FUNCTION_DECL}: +@ftable @code +@item DECL_MAIN_P +This predicate holds for a function that is the program entry point +@code{::code}. + +@item DECL_NAME +This macro returns the unqualified name of the function, as an +@code{IDENTIFIER_NODE}. For an instantiation of a function template, +the @code{DECL_NAME} is the unqualified name of the template, not +something like @code{f<int>}. The value of @code{DECL_NAME} is +undefined when used on a constructor, destructor, overloaded operator, +or type-conversion operator, or any function that is implicitly +generated by the compiler. See below for macros that can be used to +distinguish these cases. + +@item DECL_ASSEMBLER_NAME +This macro returns the mangled name of the function, also an +@code{IDENTIFIER_NODE}. This name does not contain leading underscores +on systems that prefix all identifiers with underscores. The mangled +name is computed in the same way on all platforms; if special processing +is required to deal with the object file format used on a particular +platform, it is the responsibility of the back end to perform those +modifications. (Of course, the back end should not modify +@code{DECL_ASSEMBLER_NAME} itself.) + +Using @code{DECL_ASSEMBLER_NAME} will cause additional memory to be +allocated (for the mangled name of the entity) so it should be used +only when emitting assembly code. It should not be used within the +optimizers to determine whether or not two declarations are the same, +even though some of the existing optimizers do use it in that way. +These uses will be removed over time. + +@item DECL_EXTERNAL +This predicate holds if the function is undefined. + +@item TREE_PUBLIC +This predicate holds if the function has external linkage. + +@item DECL_LOCAL_FUNCTION_P +This predicate holds if the function was declared at block scope, even +though it has a global scope. + +@item DECL_ANTICIPATED +This predicate holds if the function is a built-in function but its +prototype is not yet explicitly declared. + +@item DECL_EXTERN_C_FUNCTION_P +This predicate holds if the function is declared as an +`@code{extern "C"}' function. + +@item DECL_LINKONCE_P +This macro holds if multiple copies of this function may be emitted in +various translation units. It is the responsibility of the linker to +merge the various copies. Template instantiations are the most common +example of functions for which @code{DECL_LINKONCE_P} holds; G++ +instantiates needed templates in all translation units which require them, +and then relies on the linker to remove duplicate instantiations. + +FIXME: This macro is not yet implemented. + +@item DECL_FUNCTION_MEMBER_P +This macro holds if the function is a member of a class, rather than a +member of a namespace. + +@item DECL_STATIC_FUNCTION_P +This predicate holds if the function a static member function. + +@item DECL_NONSTATIC_MEMBER_FUNCTION_P +This macro holds for a non-static member function. + +@item DECL_CONST_MEMFUNC_P +This predicate holds for a @code{const}-member function. + +@item DECL_VOLATILE_MEMFUNC_P +This predicate holds for a @code{volatile}-member function. + +@item DECL_CONSTRUCTOR_P +This macro holds if the function is a constructor. + +@item DECL_NONCONVERTING_P +This predicate holds if the constructor is a non-converting constructor. + +@item DECL_COMPLETE_CONSTRUCTOR_P +This predicate holds for a function which is a constructor for an object +of a complete type. + +@item DECL_BASE_CONSTRUCTOR_P +This predicate holds for a function which is a constructor for a base +class sub-object. + +@item DECL_COPY_CONSTRUCTOR_P +This predicate holds for a function which is a copy-constructor. + +@item DECL_DESTRUCTOR_P +This macro holds if the function is a destructor. + +@item DECL_COMPLETE_DESTRUCTOR_P +This predicate holds if the function is the destructor for an object a +complete type. + +@item DECL_OVERLOADED_OPERATOR_P +This macro holds if the function is an overloaded operator. + +@item DECL_CONV_FN_P +This macro holds if the function is a type-conversion operator. + +@item DECL_GLOBAL_CTOR_P +This predicate holds if the function is a file-scope initialization +function. + +@item DECL_GLOBAL_DTOR_P +This predicate holds if the function is a file-scope finalization +function. + +@item DECL_THUNK_P +This predicate holds if the function is a thunk. + +These functions represent stub code that adjusts the @code{this} pointer +and then jumps to another function. When the jumped-to function +returns, control is transferred directly to the caller, without +returning to the thunk. The first parameter to the thunk is always the +@code{this} pointer; the thunk should add @code{THUNK_DELTA} to this +value. (The @code{THUNK_DELTA} is an @code{int}, not an +@code{INTEGER_CST}.) + +Then, if @code{THUNK_VCALL_OFFSET} (an @code{INTEGER_CST}) is nonzero +the adjusted @code{this} pointer must be adjusted again. The complete +calculation is given by the following pseudo-code: + +@smallexample +this += THUNK_DELTA +if (THUNK_VCALL_OFFSET) + this += (*((ptrdiff_t **) this))[THUNK_VCALL_OFFSET] +@end smallexample + +Finally, the thunk should jump to the location given +by @code{DECL_INITIAL}; this will always be an expression for the +address of a function. + +@item DECL_NON_THUNK_FUNCTION_P +This predicate holds if the function is @emph{not} a thunk function. + +@item GLOBAL_INIT_PRIORITY +If either @code{DECL_GLOBAL_CTOR_P} or @code{DECL_GLOBAL_DTOR_P} holds, +then this gives the initialization priority for the function. The +linker will arrange that all functions for which +@code{DECL_GLOBAL_CTOR_P} holds are run in increasing order of priority +before @code{main} is called. When the program exits, all functions for +which @code{DECL_GLOBAL_DTOR_P} holds are run in the reverse order. + +@item DECL_ARTIFICIAL +This macro holds if the function was implicitly generated by the +compiler, rather than explicitly declared. In addition to implicitly +generated class member functions, this macro holds for the special +functions created to implement static initialization and destruction, to +compute run-time type information, and so forth. + +@item DECL_ARGUMENTS +This macro returns the @code{PARM_DECL} for the first argument to the +function. Subsequent @code{PARM_DECL} nodes can be obtained by +following the @code{TREE_CHAIN} links. + +@item DECL_RESULT +This macro returns the @code{RESULT_DECL} for the function. + +@item TREE_TYPE +This macro returns the @code{FUNCTION_TYPE} or @code{METHOD_TYPE} for +the function. + +@item TYPE_RAISES_EXCEPTIONS +This macro returns the list of exceptions that a (member-)function can +raise. The returned list, if non @code{NULL}, is comprised of nodes +whose @code{TREE_VALUE} represents a type. + +@item TYPE_NOTHROW_P +This predicate holds when the exception-specification of its arguments +if of the form `@code{()}'. + +@item DECL_ARRAY_DELETE_OPERATOR_P +This predicate holds if the function an overloaded +@code{operator delete[]}. + +@end ftable + +@c --------------------------------------------------------------------- +@c Function Bodies +@c --------------------------------------------------------------------- + +@node Function Bodies +@subsection Function Bodies +@cindex function body +@cindex statements +@tindex BREAK_STMT +@tindex CLEANUP_STMT +@findex CLEANUP_DECL +@findex CLEANUP_EXPR +@tindex CONTINUE_STMT +@tindex DECL_STMT +@findex DECL_STMT_DECL +@tindex DO_STMT +@findex DO_BODY +@findex DO_COND +@tindex EMPTY_CLASS_EXPR +@tindex EXPR_STMT +@findex EXPR_STMT_EXPR +@tindex FOR_STMT +@findex FOR_INIT_STMT +@findex FOR_COND +@findex FOR_EXPR +@findex FOR_BODY +@tindex HANDLER +@tindex IF_STMT +@findex IF_COND +@findex THEN_CLAUSE +@findex ELSE_CLAUSE +@tindex RETURN_STMT +@findex RETURN_EXPR +@tindex SUBOBJECT +@findex SUBOBJECT_CLEANUP +@tindex SWITCH_STMT +@findex SWITCH_COND +@findex SWITCH_BODY +@tindex TRY_BLOCK +@findex TRY_STMTS +@findex TRY_HANDLERS +@findex HANDLER_PARMS +@findex HANDLER_BODY +@findex USING_STMT +@tindex WHILE_STMT +@findex WHILE_BODY +@findex WHILE_COND + +A function that has a definition in the current translation unit will +have a non-@code{NULL} @code{DECL_INITIAL}. However, back ends should not make +use of the particular value given by @code{DECL_INITIAL}. + +The @code{DECL_SAVED_TREE} macro will give the complete body of the +function. + +@subsubsection Statements + +There are tree nodes corresponding to all of the source-level +statement constructs, used within the C and C++ frontends. These are +enumerated here, together with a list of the various macros that can +be used to obtain information about them. There are a few macros that +can be used with all statements: + +@ftable @code +@item STMT_IS_FULL_EXPR_P +In C++, statements normally constitute ``full expressions''; temporaries +created during a statement are destroyed when the statement is complete. +However, G++ sometimes represents expressions by statements; these +statements will not have @code{STMT_IS_FULL_EXPR_P} set. Temporaries +created during such statements should be destroyed when the innermost +enclosing statement with @code{STMT_IS_FULL_EXPR_P} set is exited. + +@end ftable + +Here is the list of the various statement nodes, and the macros used to +access them. This documentation describes the use of these nodes in +non-template functions (including instantiations of template functions). +In template functions, the same nodes are used, but sometimes in +slightly different ways. + +Many of the statements have substatements. For example, a @code{while} +loop will have a body, which is itself a statement. If the substatement +is @code{NULL_TREE}, it is considered equivalent to a statement +consisting of a single @code{;}, i.e., an expression statement in which +the expression has been omitted. A substatement may in fact be a list +of statements, connected via their @code{TREE_CHAIN}s. So, you should +always process the statement tree by looping over substatements, like +this: +@smallexample +void process_stmt (stmt) + tree stmt; +@{ + while (stmt) + @{ + switch (TREE_CODE (stmt)) + @{ + case IF_STMT: + process_stmt (THEN_CLAUSE (stmt)); + /* @r{More processing here.} */ + break; + + @dots{} + @} + + stmt = TREE_CHAIN (stmt); + @} +@} +@end smallexample +In other words, while the @code{then} clause of an @code{if} statement +in C++ can be only one statement (although that one statement may be a +compound statement), the intermediate representation will sometimes use +several statements chained together. + +@table @code +@item ASM_EXPR + +Used to represent an inline assembly statement. For an inline assembly +statement like: +@smallexample +asm ("mov x, y"); +@end smallexample +The @code{ASM_STRING} macro will return a @code{STRING_CST} node for +@code{"mov x, y"}. If the original statement made use of the +extended-assembly syntax, then @code{ASM_OUTPUTS}, +@code{ASM_INPUTS}, and @code{ASM_CLOBBERS} will be the outputs, inputs, +and clobbers for the statement, represented as @code{STRING_CST} nodes. +The extended-assembly syntax looks like: +@smallexample +asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); +@end smallexample +The first string is the @code{ASM_STRING}, containing the instruction +template. The next two strings are the output and inputs, respectively; +this statement has no clobbers. As this example indicates, ``plain'' +assembly statements are merely a special case of extended assembly +statements; they have no cv-qualifiers, outputs, inputs, or clobbers. +All of the strings will be @code{NUL}-terminated, and will contain no +embedded @code{NUL}-characters. + +If the assembly statement is declared @code{volatile}, or if the +statement was not an extended assembly statement, and is therefore +implicitly volatile, then the predicate @code{ASM_VOLATILE_P} will hold +of the @code{ASM_EXPR}. +@c APPLE LOCAL begin CW asm blocks +@code{ASM_USES} and @code{ASM_LABEL} are for CW assembly syntax only, +providing REG_USE and label declaration information inside @code{ASM_EXPR} +tree. +@c APPLE LOCAL end CW asm blocks + +@item BREAK_STMT + +Used to represent a @code{break} statement. There are no additional +fields. + +@item CASE_LABEL_EXPR + +Use to represent a @code{case} label, range of @code{case} labels, or a +@code{default} label. If @code{CASE_LOW} is @code{NULL_TREE}, then this is a +@code{default} label. Otherwise, if @code{CASE_HIGH} is @code{NULL_TREE}, then +this is an ordinary @code{case} label. In this case, @code{CASE_LOW} is +an expression giving the value of the label. Both @code{CASE_LOW} and +@code{CASE_HIGH} are @code{INTEGER_CST} nodes. These values will have +the same type as the condition expression in the switch statement. + +Otherwise, if both @code{CASE_LOW} and @code{CASE_HIGH} are defined, the +statement is a range of case labels. Such statements originate with the +extension that allows users to write things of the form: +@smallexample +case 2 ... 5: +@end smallexample +The first value will be @code{CASE_LOW}, while the second will be +@code{CASE_HIGH}. + +@item CLEANUP_STMT + +Used to represent an action that should take place upon exit from the +enclosing scope. Typically, these actions are calls to destructors for +local objects, but back ends cannot rely on this fact. If these nodes +are in fact representing such destructors, @code{CLEANUP_DECL} will be +the @code{VAR_DECL} destroyed. Otherwise, @code{CLEANUP_DECL} will be +@code{NULL_TREE}. In any case, the @code{CLEANUP_EXPR} is the +expression to execute. The cleanups executed on exit from a scope +should be run in the reverse order of the order in which the associated +@code{CLEANUP_STMT}s were encountered. + +@item CONTINUE_STMT + +Used to represent a @code{continue} statement. There are no additional +fields. + +@item CTOR_STMT + +Used to mark the beginning (if @code{CTOR_BEGIN_P} holds) or end (if +@code{CTOR_END_P} holds of the main body of a constructor. See also +@code{SUBOBJECT} for more information on how to use these nodes. + +@item DECL_STMT + +Used to represent a local declaration. The @code{DECL_STMT_DECL} macro +can be used to obtain the entity declared. This declaration may be a +@code{LABEL_DECL}, indicating that the label declared is a local label. +(As an extension, GCC allows the declaration of labels with scope.) In +C, this declaration may be a @code{FUNCTION_DECL}, indicating the +use of the GCC nested function extension. For more information, +@pxref{Functions}. + +@item DO_STMT + +Used to represent a @code{do} loop. The body of the loop is given by +@code{DO_BODY} while the termination condition for the loop is given by +@code{DO_COND}. The condition for a @code{do}-statement is always an +expression. + +@item EMPTY_CLASS_EXPR + +Used to represent a temporary object of a class with no data whose +address is never taken. (All such objects are interchangeable.) The +@code{TREE_TYPE} represents the type of the object. + +@item EXPR_STMT + +Used to represent an expression statement. Use @code{EXPR_STMT_EXPR} to +obtain the expression. + +@item FOR_STMT + +Used to represent a @code{for} statement. The @code{FOR_INIT_STMT} is +the initialization statement for the loop. The @code{FOR_COND} is the +termination condition. The @code{FOR_EXPR} is the expression executed +right before the @code{FOR_COND} on each loop iteration; often, this +expression increments a counter. The body of the loop is given by +@code{FOR_BODY}. Note that @code{FOR_INIT_STMT} and @code{FOR_BODY} +return statements, while @code{FOR_COND} and @code{FOR_EXPR} return +expressions. + +@item GOTO_EXPR + +Used to represent a @code{goto} statement. The @code{GOTO_DESTINATION} will +usually be a @code{LABEL_DECL}. However, if the ``computed goto'' extension +has been used, the @code{GOTO_DESTINATION} will be an arbitrary expression +indicating the destination. This expression will always have pointer type. + +@item HANDLER + +Used to represent a C++ @code{catch} block. The @code{HANDLER_TYPE} +is the type of exception that will be caught by this handler; it is +equal (by pointer equality) to @code{NULL} if this handler is for all +types. @code{HANDLER_PARMS} is the @code{DECL_STMT} for the catch +parameter, and @code{HANDLER_BODY} is the code for the block itself. + +@item IF_STMT + +Used to represent an @code{if} statement. The @code{IF_COND} is the +expression. + +If the condition is a @code{TREE_LIST}, then the @code{TREE_PURPOSE} is +a statement (usually a @code{DECL_STMT}). Each time the condition is +evaluated, the statement should be executed. Then, the +@code{TREE_VALUE} should be used as the conditional expression itself. +This representation is used to handle C++ code like this: + +@smallexample +if (int i = 7) @dots{} +@end smallexample + +where there is a new local variable (or variables) declared within the +condition. + +The @code{THEN_CLAUSE} represents the statement given by the @code{then} +condition, while the @code{ELSE_CLAUSE} represents the statement given +by the @code{else} condition. + +@item LABEL_EXPR + +Used to represent a label. The @code{LABEL_DECL} declared by this +statement can be obtained with the @code{LABEL_EXPR_LABEL} macro. The +@code{IDENTIFIER_NODE} giving the name of the label can be obtained from +the @code{LABEL_DECL} with @code{DECL_NAME}. + +@item RETURN_STMT + +Used to represent a @code{return} statement. The @code{RETURN_EXPR} is +the expression returned; it will be @code{NULL_TREE} if the statement +was just +@smallexample +return; +@end smallexample + +@item SUBOBJECT + +In a constructor, these nodes are used to mark the point at which a +subobject of @code{this} is fully constructed. If, after this point, an +exception is thrown before a @code{CTOR_STMT} with @code{CTOR_END_P} set +is encountered, the @code{SUBOBJECT_CLEANUP} must be executed. The +cleanups must be executed in the reverse order in which they appear. + +@item SWITCH_STMT + +Used to represent a @code{switch} statement. The @code{SWITCH_STMT_COND} +is the expression on which the switch is occurring. See the documentation +for an @code{IF_STMT} for more information on the representation used +for the condition. The @code{SWITCH_STMT_BODY} is the body of the switch +statement. The @code{SWITCH_STMT_TYPE} is the original type of switch +expression as given in the source, before any compiler conversions. + +@item TRY_BLOCK +Used to represent a @code{try} block. The body of the try block is +given by @code{TRY_STMTS}. Each of the catch blocks is a @code{HANDLER} +node. The first handler is given by @code{TRY_HANDLERS}. Subsequent +handlers are obtained by following the @code{TREE_CHAIN} link from one +handler to the next. The body of the handler is given by +@code{HANDLER_BODY}. + +If @code{CLEANUP_P} holds of the @code{TRY_BLOCK}, then the +@code{TRY_HANDLERS} will not be a @code{HANDLER} node. Instead, it will +be an expression that should be executed if an exception is thrown in +the try block. It must rethrow the exception after executing that code. +And, if an exception is thrown while the expression is executing, +@code{terminate} must be called. + +@item USING_STMT +Used to represent a @code{using} directive. The namespace is given by +@code{USING_STMT_NAMESPACE}, which will be a NAMESPACE_DECL@. This node +is needed inside template functions, to implement using directives +during instantiation. + +@item WHILE_STMT + +Used to represent a @code{while} loop. The @code{WHILE_COND} is the +termination condition for the loop. See the documentation for an +@code{IF_STMT} for more information on the representation used for the +condition. + +The @code{WHILE_BODY} is the body of the loop. + +@end table + +@c --------------------------------------------------------------------- +@c Attributes +@c --------------------------------------------------------------------- +@node Attributes +@section Attributes in trees +@cindex attributes + +Attributes, as specified using the @code{__attribute__} keyword, are +represented internally as a @code{TREE_LIST}. The @code{TREE_PURPOSE} +is the name of the attribute, as an @code{IDENTIFIER_NODE}. The +@code{TREE_VALUE} is a @code{TREE_LIST} of the arguments of the +attribute, if any, or @code{NULL_TREE} if there are no arguments; the +arguments are stored as the @code{TREE_VALUE} of successive entries in +the list, and may be identifiers or expressions. The @code{TREE_CHAIN} +of the attribute is the next attribute in a list of attributes applying +to the same declaration or type, or @code{NULL_TREE} if there are no +further attributes in the list. + +Attributes may be attached to declarations and to types; these +attributes may be accessed with the following macros. All attributes +are stored in this way, and many also cause other changes to the +declaration or type or to other internal compiler data structures. + +@deftypefn {Tree Macro} tree DECL_ATTRIBUTES (tree @var{decl}) +This macro returns the attributes on the declaration @var{decl}. +@end deftypefn + +@deftypefn {Tree Macro} tree TYPE_ATTRIBUTES (tree @var{type}) +This macro returns the attributes on the type @var{type}. +@end deftypefn + +@c --------------------------------------------------------------------- +@c Expressions +@c --------------------------------------------------------------------- + +@node Expression trees +@section Expressions +@cindex expression +@findex TREE_TYPE +@findex TREE_OPERAND +@tindex INTEGER_CST +@findex TREE_INT_CST_HIGH +@findex TREE_INT_CST_LOW +@findex tree_int_cst_lt +@findex tree_int_cst_equal +@tindex REAL_CST +@tindex COMPLEX_CST +@tindex VECTOR_CST +@tindex STRING_CST +@findex TREE_STRING_LENGTH +@findex TREE_STRING_POINTER +@tindex PTRMEM_CST +@findex PTRMEM_CST_CLASS +@findex PTRMEM_CST_MEMBER +@tindex VAR_DECL +@tindex NEGATE_EXPR +@tindex ABS_EXPR +@tindex BIT_NOT_EXPR +@tindex TRUTH_NOT_EXPR +@tindex PREDECREMENT_EXPR +@tindex PREINCREMENT_EXPR +@tindex POSTDECREMENT_EXPR +@tindex POSTINCREMENT_EXPR +@tindex ADDR_EXPR +@tindex INDIRECT_REF +@tindex FIX_TRUNC_EXPR +@tindex FLOAT_EXPR +@tindex COMPLEX_EXPR +@tindex CONJ_EXPR +@tindex REALPART_EXPR +@tindex IMAGPART_EXPR +@tindex NON_LVALUE_EXPR +@tindex NOP_EXPR +@tindex CONVERT_EXPR +@tindex THROW_EXPR +@tindex LSHIFT_EXPR +@tindex RSHIFT_EXPR +@tindex BIT_IOR_EXPR +@tindex BIT_XOR_EXPR +@tindex BIT_AND_EXPR +@tindex TRUTH_ANDIF_EXPR +@tindex TRUTH_ORIF_EXPR +@tindex TRUTH_AND_EXPR +@tindex TRUTH_OR_EXPR +@tindex TRUTH_XOR_EXPR +@tindex PLUS_EXPR +@tindex MINUS_EXPR +@tindex MULT_EXPR +@tindex RDIV_EXPR +@tindex TRUNC_DIV_EXPR +@tindex FLOOR_DIV_EXPR +@tindex CEIL_DIV_EXPR +@tindex ROUND_DIV_EXPR +@tindex TRUNC_MOD_EXPR +@tindex FLOOR_MOD_EXPR +@tindex CEIL_MOD_EXPR +@tindex ROUND_MOD_EXPR +@tindex EXACT_DIV_EXPR +@tindex ARRAY_REF +@tindex ARRAY_RANGE_REF +@tindex TARGET_MEM_REF +@tindex LT_EXPR +@tindex LE_EXPR +@tindex GT_EXPR +@tindex GE_EXPR +@tindex EQ_EXPR +@tindex NE_EXPR +@tindex ORDERED_EXPR +@tindex UNORDERED_EXPR +@tindex UNLT_EXPR +@tindex UNLE_EXPR +@tindex UNGT_EXPR +@tindex UNGE_EXPR +@tindex UNEQ_EXPR +@tindex LTGT_EXPR +@tindex MODIFY_EXPR +@tindex INIT_EXPR +@tindex COMPONENT_REF +@tindex COMPOUND_EXPR +@tindex COND_EXPR +@tindex CALL_EXPR +@tindex STMT_EXPR +@tindex BIND_EXPR +@tindex LOOP_EXPR +@tindex EXIT_EXPR +@tindex CLEANUP_POINT_EXPR +@tindex CONSTRUCTOR +@tindex COMPOUND_LITERAL_EXPR +@tindex SAVE_EXPR +@tindex TARGET_EXPR +@tindex AGGR_INIT_EXPR +@tindex VA_ARG_EXPR +@tindex OMP_PARALLEL +@tindex OMP_FOR +@tindex OMP_SECTIONS +@tindex OMP_SINGLE +@tindex OMP_SECTION +@tindex OMP_MASTER +@tindex OMP_ORDERED +@tindex OMP_CRITICAL +@tindex OMP_RETURN +@tindex OMP_CONTINUE +@tindex OMP_ATOMIC +@tindex OMP_CLAUSE + +The internal representation for expressions is for the most part quite +straightforward. However, there are a few facts that one must bear in +mind. In particular, the expression ``tree'' is actually a directed +acyclic graph. (For example there may be many references to the integer +constant zero throughout the source program; many of these will be +represented by the same expression node.) You should not rely on +certain kinds of node being shared, nor should rely on certain kinds of +nodes being unshared. + +The following macros can be used with all expression nodes: + +@ftable @code +@item TREE_TYPE +Returns the type of the expression. This value may not be precisely the +same type that would be given the expression in the original program. +@end ftable + +In what follows, some nodes that one might expect to always have type +@code{bool} are documented to have either integral or boolean type. At +some point in the future, the C front end may also make use of this same +intermediate representation, and at this point these nodes will +certainly have integral type. The previous sentence is not meant to +imply that the C++ front end does not or will not give these nodes +integral type. + +Below, we list the various kinds of expression nodes. Except where +noted otherwise, the operands to an expression are accessed using the +@code{TREE_OPERAND} macro. For example, to access the first operand to +a binary plus expression @code{expr}, use: + +@smallexample +TREE_OPERAND (expr, 0) +@end smallexample +@noindent +As this example indicates, the operands are zero-indexed. + +All the expressions starting with @code{OMP_} represent directives and +clauses used by the OpenMP API @w{@uref{http://www.openmp.org/}}. + +The table below begins with constants, moves on to unary expressions, +then proceeds to binary expressions, and concludes with various other +kinds of expressions: + +@table @code +@item INTEGER_CST +These nodes represent integer constants. Note that the type of these +constants is obtained with @code{TREE_TYPE}; they are not always of type +@code{int}. In particular, @code{char} constants are represented with +@code{INTEGER_CST} nodes. The value of the integer constant @code{e} is +given by +@smallexample +((TREE_INT_CST_HIGH (e) << HOST_BITS_PER_WIDE_INT) ++ TREE_INST_CST_LOW (e)) +@end smallexample +@noindent +HOST_BITS_PER_WIDE_INT is at least thirty-two on all platforms. Both +@code{TREE_INT_CST_HIGH} and @code{TREE_INT_CST_LOW} return a +@code{HOST_WIDE_INT}. The value of an @code{INTEGER_CST} is interpreted +as a signed or unsigned quantity depending on the type of the constant. +In general, the expression given above will overflow, so it should not +be used to calculate the value of the constant. + +The variable @code{integer_zero_node} is an integer constant with value +zero. Similarly, @code{integer_one_node} is an integer constant with +value one. The @code{size_zero_node} and @code{size_one_node} variables +are analogous, but have type @code{size_t} rather than @code{int}. + +The function @code{tree_int_cst_lt} is a predicate which holds if its +first argument is less than its second. Both constants are assumed to +have the same signedness (i.e., either both should be signed or both +should be unsigned.) The full width of the constant is used when doing +the comparison; the usual rules about promotions and conversions are +ignored. Similarly, @code{tree_int_cst_equal} holds if the two +constants are equal. The @code{tree_int_cst_sgn} function returns the +sign of a constant. The value is @code{1}, @code{0}, or @code{-1} +according on whether the constant is greater than, equal to, or less +than zero. Again, the signedness of the constant's type is taken into +account; an unsigned constant is never less than zero, no matter what +its bit-pattern. + +@item REAL_CST + +FIXME: Talk about how to obtain representations of this constant, do +comparisons, and so forth. + +@item COMPLEX_CST +These nodes are used to represent complex number constants, that is a +@code{__complex__} whose parts are constant nodes. The +@code{TREE_REALPART} and @code{TREE_IMAGPART} return the real and the +imaginary parts respectively. + +@item VECTOR_CST +These nodes are used to represent vector constants, whose parts are +constant nodes. Each individual constant node is either an integer or a +double constant node. The first operand is a @code{TREE_LIST} of the +constant nodes and is accessed through @code{TREE_VECTOR_CST_ELTS}. + +@item STRING_CST +These nodes represent string-constants. The @code{TREE_STRING_LENGTH} +returns the length of the string, as an @code{int}. The +@code{TREE_STRING_POINTER} is a @code{char*} containing the string +itself. The string may not be @code{NUL}-terminated, and it may contain +embedded @code{NUL} characters. Therefore, the +@code{TREE_STRING_LENGTH} includes the trailing @code{NUL} if it is +present. + +For wide string constants, the @code{TREE_STRING_LENGTH} is the number +of bytes in the string, and the @code{TREE_STRING_POINTER} +points to an array of the bytes of the string, as represented on the +target system (that is, as integers in the target endianness). Wide and +non-wide string constants are distinguished only by the @code{TREE_TYPE} +of the @code{STRING_CST}. + +FIXME: The formats of string constants are not well-defined when the +target system bytes are not the same width as host system bytes. + +@item PTRMEM_CST +These nodes are used to represent pointer-to-member constants. The +@code{PTRMEM_CST_CLASS} is the class type (either a @code{RECORD_TYPE} +or @code{UNION_TYPE} within which the pointer points), and the +@code{PTRMEM_CST_MEMBER} is the declaration for the pointed to object. +Note that the @code{DECL_CONTEXT} for the @code{PTRMEM_CST_MEMBER} is in +general different from the @code{PTRMEM_CST_CLASS}. For example, +given: +@smallexample +struct B @{ int i; @}; +struct D : public B @{@}; +int D::*dp = &D::i; +@end smallexample +@noindent +The @code{PTRMEM_CST_CLASS} for @code{&D::i} is @code{D}, even though +the @code{DECL_CONTEXT} for the @code{PTRMEM_CST_MEMBER} is @code{B}, +since @code{B::i} is a member of @code{B}, not @code{D}. + +@item VAR_DECL + +These nodes represent variables, including static data members. For +more information, @pxref{Declarations}. + +@item NEGATE_EXPR +These nodes represent unary negation of the single operand, for both +integer and floating-point types. The type of negation can be +determined by looking at the type of the expression. + +The behavior of this operation on signed arithmetic overflow is +controlled by the @code{flag_wrapv} and @code{flag_trapv} variables. + +@item ABS_EXPR +These nodes represent the absolute value of the single operand, for +both integer and floating-point types. This is typically used to +implement the @code{abs}, @code{labs} and @code{llabs} builtins for +integer types, and the @code{fabs}, @code{fabsf} and @code{fabsl} +builtins for floating point types. The type of abs operation can +be determined by looking at the type of the expression. + +This node is not used for complex types. To represent the modulus +or complex abs of a complex value, use the @code{BUILT_IN_CABS}, +@code{BUILT_IN_CABSF} or @code{BUILT_IN_CABSL} builtins, as used +to implement the C99 @code{cabs}, @code{cabsf} and @code{cabsl} +built-in functions. + +@item BIT_NOT_EXPR +These nodes represent bitwise complement, and will always have integral +type. The only operand is the value to be complemented. + +@item TRUTH_NOT_EXPR +These nodes represent logical negation, and will always have integral +(or boolean) type. The operand is the value being negated. The type +of the operand and that of the result are always of @code{BOOLEAN_TYPE} +or @code{INTEGER_TYPE}. + +@item PREDECREMENT_EXPR +@itemx PREINCREMENT_EXPR +@itemx POSTDECREMENT_EXPR +@itemx POSTINCREMENT_EXPR +These nodes represent increment and decrement expressions. The value of +the single operand is computed, and the operand incremented or +decremented. In the case of @code{PREDECREMENT_EXPR} and +@code{PREINCREMENT_EXPR}, the value of the expression is the value +resulting after the increment or decrement; in the case of +@code{POSTDECREMENT_EXPR} and @code{POSTINCREMENT_EXPR} is the value +before the increment or decrement occurs. The type of the operand, like +that of the result, will be either integral, boolean, or floating-point. + +@item ADDR_EXPR +These nodes are used to represent the address of an object. (These +expressions will always have pointer or reference type.) The operand may +be another expression, or it may be a declaration. + +As an extension, GCC allows users to take the address of a label. In +this case, the operand of the @code{ADDR_EXPR} will be a +@code{LABEL_DECL}. The type of such an expression is @code{void*}. + +If the object addressed is not an lvalue, a temporary is created, and +the address of the temporary is used. + +@item INDIRECT_REF +These nodes are used to represent the object pointed to by a pointer. +The operand is the pointer being dereferenced; it will always have +pointer or reference type. + +@item FIX_TRUNC_EXPR +These nodes represent conversion of a floating-point value to an +integer. The single operand will have a floating-point type, while +the complete expression will have an integral (or boolean) type. The +operand is rounded towards zero. + +@item FLOAT_EXPR +These nodes represent conversion of an integral (or boolean) value to a +floating-point value. The single operand will have integral type, while +the complete expression will have a floating-point type. + +FIXME: How is the operand supposed to be rounded? Is this dependent on +@option{-mieee}? + +@item COMPLEX_EXPR +These nodes are used to represent complex numbers constructed from two +expressions of the same (integer or real) type. The first operand is the +real part and the second operand is the imaginary part. + +@item CONJ_EXPR +These nodes represent the conjugate of their operand. + +@item REALPART_EXPR +@itemx IMAGPART_EXPR +These nodes represent respectively the real and the imaginary parts +of complex numbers (their sole argument). + +@item NON_LVALUE_EXPR +These nodes indicate that their one and only operand is not an lvalue. +A back end can treat these identically to the single operand. + +@item NOP_EXPR +These nodes are used to represent conversions that do not require any +code-generation. For example, conversion of a @code{char*} to an +@code{int*} does not require any code be generated; such a conversion is +represented by a @code{NOP_EXPR}. The single operand is the expression +to be converted. The conversion from a pointer to a reference is also +represented with a @code{NOP_EXPR}. + +@item CONVERT_EXPR +These nodes are similar to @code{NOP_EXPR}s, but are used in those +situations where code may need to be generated. For example, if an +@code{int*} is converted to an @code{int} code may need to be generated +on some platforms. These nodes are never used for C++-specific +conversions, like conversions between pointers to different classes in +an inheritance hierarchy. Any adjustments that need to be made in such +cases are always indicated explicitly. Similarly, a user-defined +conversion is never represented by a @code{CONVERT_EXPR}; instead, the +function calls are made explicit. + +@item THROW_EXPR +These nodes represent @code{throw} expressions. The single operand is +an expression for the code that should be executed to throw the +exception. However, there is one implicit action not represented in +that expression; namely the call to @code{__throw}. This function takes +no arguments. If @code{setjmp}/@code{longjmp} exceptions are used, the +function @code{__sjthrow} is called instead. The normal GCC back end +uses the function @code{emit_throw} to generate this code; you can +examine this function to see what needs to be done. + +@item LSHIFT_EXPR +@itemx RSHIFT_EXPR +These nodes represent left and right shifts, respectively. The first +operand is the value to shift; it will always be of integral type. The +second operand is an expression for the number of bits by which to +shift. Right shift should be treated as arithmetic, i.e., the +high-order bits should be zero-filled when the expression has unsigned +type and filled with the sign bit when the expression has signed type. +Note that the result is undefined if the second operand is larger +than or equal to the first operand's type size. + + +@item BIT_IOR_EXPR +@itemx BIT_XOR_EXPR +@itemx BIT_AND_EXPR +These nodes represent bitwise inclusive or, bitwise exclusive or, and +bitwise and, respectively. Both operands will always have integral +type. + +@item TRUTH_ANDIF_EXPR +@itemx TRUTH_ORIF_EXPR +These nodes represent logical and and logical or, respectively. These +operators are not strict; i.e., the second operand is evaluated only if +the value of the expression is not determined by evaluation of the first +operand. The type of the operands and that of the result are always of +@code{BOOLEAN_TYPE} or @code{INTEGER_TYPE}. + +@item TRUTH_AND_EXPR +@itemx TRUTH_OR_EXPR +@itemx TRUTH_XOR_EXPR +These nodes represent logical and, logical or, and logical exclusive or. +They are strict; both arguments are always evaluated. There are no +corresponding operators in C or C++, but the front end will sometimes +generate these expressions anyhow, if it can tell that strictness does +not matter. The type of the operands and that of the result are +always of @code{BOOLEAN_TYPE} or @code{INTEGER_TYPE}. + +@itemx PLUS_EXPR +@itemx MINUS_EXPR +@itemx MULT_EXPR +These nodes represent various binary arithmetic operations. +Respectively, these operations are addition, subtraction (of the second +operand from the first) and multiplication. Their operands may have +either integral or floating type, but there will never be case in which +one operand is of floating type and the other is of integral type. + +The behavior of these operations on signed arithmetic overflow is +controlled by the @code{flag_wrapv} and @code{flag_trapv} variables. + +@item RDIV_EXPR +This node represents a floating point division operation. + +@item TRUNC_DIV_EXPR +@itemx FLOOR_DIV_EXPR +@itemx CEIL_DIV_EXPR +@itemx ROUND_DIV_EXPR +These nodes represent integer division operations that return an integer +result. @code{TRUNC_DIV_EXPR} rounds towards zero, @code{FLOOR_DIV_EXPR} +rounds towards negative infinity, @code{CEIL_DIV_EXPR} rounds towards +positive infinity and @code{ROUND_DIV_EXPR} rounds to the closest integer. +Integer division in C and C++ is truncating, i.e.@: @code{TRUNC_DIV_EXPR}. + +The behavior of these operations on signed arithmetic overflow, when +dividing the minimum signed integer by minus one, is controlled by the +@code{flag_wrapv} and @code{flag_trapv} variables. + +@item TRUNC_MOD_EXPR +@itemx FLOOR_MOD_EXPR +@itemx CEIL_MOD_EXPR +@itemx ROUND_MOD_EXPR +These nodes represent the integer remainder or modulus operation. +The integer modulus of two operands @code{a} and @code{b} is +defined as @code{a - (a/b)*b} where the division calculated using +the corresponding division operator. Hence for @code{TRUNC_MOD_EXPR} +this definition assumes division using truncation towards zero, i.e.@: +@code{TRUNC_DIV_EXPR}. Integer remainder in C and C++ uses truncating +division, i.e.@: @code{TRUNC_MOD_EXPR}. + +@item EXACT_DIV_EXPR +The @code{EXACT_DIV_EXPR} code is used to represent integer divisions where +the numerator is known to be an exact multiple of the denominator. This +allows the backend to choose between the faster of @code{TRUNC_DIV_EXPR}, +@code{CEIL_DIV_EXPR} and @code{FLOOR_DIV_EXPR} for the current target. + +@item ARRAY_REF +These nodes represent array accesses. The first operand is the array; +the second is the index. To calculate the address of the memory +accessed, you must scale the index by the size of the type of the array +elements. The type of these expressions must be the type of a component of +the array. The third and fourth operands are used after gimplification +to represent the lower bound and component size but should not be used +directly; call @code{array_ref_low_bound} and @code{array_ref_element_size} +instead. + +@item ARRAY_RANGE_REF +These nodes represent access to a range (or ``slice'') of an array. The +operands are the same as that for @code{ARRAY_REF} and have the same +meanings. The type of these expressions must be an array whose component +type is the same as that of the first operand. The range of that array +type determines the amount of data these expressions access. + +@item TARGET_MEM_REF +These nodes represent memory accesses whose address directly map to +an addressing mode of the target architecture. The first argument +is @code{TMR_SYMBOL} and must be a @code{VAR_DECL} of an object with +a fixed address. The second argument is @code{TMR_BASE} and the +third one is @code{TMR_INDEX}. The fourth argument is +@code{TMR_STEP} and must be an @code{INTEGER_CST}. The fifth +argument is @code{TMR_OFFSET} and must be an @code{INTEGER_CST}. +Any of the arguments may be NULL if the appropriate component +does not appear in the address. Address of the @code{TARGET_MEM_REF} +is determined in the following way. + +@smallexample +&TMR_SYMBOL + TMR_BASE + TMR_INDEX * TMR_STEP + TMR_OFFSET +@end smallexample + +The sixth argument is the reference to the original memory access, which +is preserved for the purposes of the RTL alias analysis. The seventh +argument is a tag representing the results of tree level alias analysis. + +@item LT_EXPR +@itemx LE_EXPR +@itemx GT_EXPR +@itemx GE_EXPR +@itemx EQ_EXPR +@itemx NE_EXPR +These nodes represent the less than, less than or equal to, greater +than, greater than or equal to, equal, and not equal comparison +operators. The first and second operand with either be both of integral +type or both of floating type. The result type of these expressions +will always be of integral or boolean type. These operations return +the result type's zero value for false, and the result type's one value +for true. + +For floating point comparisons, if we honor IEEE NaNs and either operand +is NaN, then @code{NE_EXPR} always returns true and the remaining operators +always return false. On some targets, comparisons against an IEEE NaN, +other than equality and inequality, may generate a floating point exception. + +@item ORDERED_EXPR +@itemx UNORDERED_EXPR +These nodes represent non-trapping ordered and unordered comparison +operators. These operations take two floating point operands and +determine whether they are ordered or unordered relative to each other. +If either operand is an IEEE NaN, their comparison is defined to be +unordered, otherwise the comparison is defined to be ordered. The +result type of these expressions will always be of integral or boolean +type. These operations return the result type's zero value for false, +and the result type's one value for true. + +@item UNLT_EXPR +@itemx UNLE_EXPR +@itemx UNGT_EXPR +@itemx UNGE_EXPR +@itemx UNEQ_EXPR +@itemx LTGT_EXPR +These nodes represent the unordered comparison operators. +These operations take two floating point operands and determine whether +the operands are unordered or are less than, less than or equal to, +greater than, greater than or equal to, or equal respectively. For +example, @code{UNLT_EXPR} returns true if either operand is an IEEE +NaN or the first operand is less than the second. With the possible +exception of @code{LTGT_EXPR}, all of these operations are guaranteed +not to generate a floating point exception. The result +type of these expressions will always be of integral or boolean type. +These operations return the result type's zero value for false, +and the result type's one value for true. + +@item MODIFY_EXPR +These nodes represent assignment. The left-hand side is the first +operand; the right-hand side is the second operand. The left-hand side +will be a @code{VAR_DECL}, @code{INDIRECT_REF}, @code{COMPONENT_REF}, or +other lvalue. + +These nodes are used to represent not only assignment with @samp{=} but +also compound assignments (like @samp{+=}), by reduction to @samp{=} +assignment. In other words, the representation for @samp{i += 3} looks +just like that for @samp{i = i + 3}. + +@item INIT_EXPR +These nodes are just like @code{MODIFY_EXPR}, but are used only when a +variable is initialized, rather than assigned to subsequently. This +means that we can assume that the target of the initialization is not +used in computing its own value; any reference to the lhs in computing +the rhs is undefined. + +@item COMPONENT_REF +These nodes represent non-static data member accesses. The first +operand is the object (rather than a pointer to it); the second operand +is the @code{FIELD_DECL} for the data member. The third operand represents +the byte offset of the field, but should not be used directly; call +@code{component_ref_field_offset} instead. + +@item COMPOUND_EXPR +These nodes represent comma-expressions. The first operand is an +expression whose value is computed and thrown away prior to the +evaluation of the second operand. The value of the entire expression is +the value of the second operand. + +@item COND_EXPR +These nodes represent @code{?:} expressions. The first operand +is of boolean or integral type. If it evaluates to a nonzero value, +the second operand should be evaluated, and returned as the value of the +expression. Otherwise, the third operand is evaluated, and returned as +the value of the expression. + +The second operand must have the same type as the entire expression, +unless it unconditionally throws an exception or calls a noreturn +function, in which case it should have void type. The same constraints +apply to the third operand. This allows array bounds checks to be +represented conveniently as @code{(i >= 0 && i < 10) ? i : abort()}. + +As a GNU extension, the C language front-ends allow the second +operand of the @code{?:} operator may be omitted in the source. +For example, @code{x ? : 3} is equivalent to @code{x ? x : 3}, +assuming that @code{x} is an expression without side-effects. +In the tree representation, however, the second operand is always +present, possibly protected by @code{SAVE_EXPR} if the first +argument does cause side-effects. + +@item CALL_EXPR +These nodes are used to represent calls to functions, including +non-static member functions. The first operand is a pointer to the +function to call; it is always an expression whose type is a +@code{POINTER_TYPE}. The second argument is a @code{TREE_LIST}. The +arguments to the call appear left-to-right in the list. The +@code{TREE_VALUE} of each list node contains the expression +corresponding to that argument. (The value of @code{TREE_PURPOSE} for +these nodes is unspecified, and should be ignored.) For non-static +member functions, there will be an operand corresponding to the +@code{this} pointer. There will always be expressions corresponding to +all of the arguments, even if the function is declared with default +arguments and some arguments are not explicitly provided at the call +sites. + +@item STMT_EXPR +These nodes are used to represent GCC's statement-expression extension. +The statement-expression extension allows code like this: +@smallexample +int f() @{ return (@{ int j; j = 3; j + 7; @}); @} +@end smallexample +In other words, an sequence of statements may occur where a single +expression would normally appear. The @code{STMT_EXPR} node represents +such an expression. The @code{STMT_EXPR_STMT} gives the statement +contained in the expression. The value of the expression is the value +of the last sub-statement in the body. More precisely, the value is the +value computed by the last statement nested inside @code{BIND_EXPR}, +@code{TRY_FINALLY_EXPR}, or @code{TRY_CATCH_EXPR}. For example, in: +@smallexample +(@{ 3; @}) +@end smallexample +the value is @code{3} while in: +@smallexample +(@{ if (x) @{ 3; @} @}) +@end smallexample +there is no value. If the @code{STMT_EXPR} does not yield a value, +it's type will be @code{void}. + +@item BIND_EXPR +These nodes represent local blocks. The first operand is a list of +variables, connected via their @code{TREE_CHAIN} field. These will +never require cleanups. The scope of these variables is just the body +of the @code{BIND_EXPR}. The body of the @code{BIND_EXPR} is the +second operand. + +@item LOOP_EXPR +These nodes represent ``infinite'' loops. The @code{LOOP_EXPR_BODY} +represents the body of the loop. It should be executed forever, unless +an @code{EXIT_EXPR} is encountered. + +@item EXIT_EXPR +These nodes represent conditional exits from the nearest enclosing +@code{LOOP_EXPR}. The single operand is the condition; if it is +nonzero, then the loop should be exited. An @code{EXIT_EXPR} will only +appear within a @code{LOOP_EXPR}. + +@item CLEANUP_POINT_EXPR +These nodes represent full-expressions. The single operand is an +expression to evaluate. Any destructor calls engendered by the creation +of temporaries during the evaluation of that expression should be +performed immediately after the expression is evaluated. + +@item CONSTRUCTOR +These nodes represent the brace-enclosed initializers for a structure or +array. The first operand is reserved for use by the back end. The +second operand is a @code{TREE_LIST}. If the @code{TREE_TYPE} of the +@code{CONSTRUCTOR} is a @code{RECORD_TYPE} or @code{UNION_TYPE}, then +the @code{TREE_PURPOSE} of each node in the @code{TREE_LIST} will be a +@code{FIELD_DECL} and the @code{TREE_VALUE} of each node will be the +expression used to initialize that field. + +If the @code{TREE_TYPE} of the @code{CONSTRUCTOR} is an +@code{ARRAY_TYPE}, then the @code{TREE_PURPOSE} of each element in the +@code{TREE_LIST} will be an @code{INTEGER_CST} or a @code{RANGE_EXPR} of +two @code{INTEGER_CST}s. A single @code{INTEGER_CST} indicates which +element of the array (indexed from zero) is being assigned to. A +@code{RANGE_EXPR} indicates an inclusive range of elements to +initialize. In both cases the @code{TREE_VALUE} is the corresponding +initializer. It is re-evaluated for each element of a +@code{RANGE_EXPR}. If the @code{TREE_PURPOSE} is @code{NULL_TREE}, then +the initializer is for the next available array element. + +In the front end, you should not depend on the fields appearing in any +particular order. However, in the middle end, fields must appear in +declaration order. You should not assume that all fields will be +represented. Unrepresented fields will be set to zero. + +@item COMPOUND_LITERAL_EXPR +@findex COMPOUND_LITERAL_EXPR_DECL_STMT +@findex COMPOUND_LITERAL_EXPR_DECL +These nodes represent ISO C99 compound literals. The +@code{COMPOUND_LITERAL_EXPR_DECL_STMT} is a @code{DECL_STMT} +containing an anonymous @code{VAR_DECL} for +the unnamed object represented by the compound literal; the +@code{DECL_INITIAL} of that @code{VAR_DECL} is a @code{CONSTRUCTOR} +representing the brace-enclosed list of initializers in the compound +literal. That anonymous @code{VAR_DECL} can also be accessed directly +by the @code{COMPOUND_LITERAL_EXPR_DECL} macro. + +@item SAVE_EXPR + +A @code{SAVE_EXPR} represents an expression (possibly involving +side-effects) that is used more than once. The side-effects should +occur only the first time the expression is evaluated. Subsequent uses +should just reuse the computed value. The first operand to the +@code{SAVE_EXPR} is the expression to evaluate. The side-effects should +be executed where the @code{SAVE_EXPR} is first encountered in a +depth-first preorder traversal of the expression tree. + +@item TARGET_EXPR +A @code{TARGET_EXPR} represents a temporary object. The first operand +is a @code{VAR_DECL} for the temporary variable. The second operand is +the initializer for the temporary. The initializer is evaluated and, +if non-void, copied (bitwise) into the temporary. If the initializer +is void, that means that it will perform the initialization itself. + +Often, a @code{TARGET_EXPR} occurs on the right-hand side of an +assignment, or as the second operand to a comma-expression which is +itself the right-hand side of an assignment, etc. In this case, we say +that the @code{TARGET_EXPR} is ``normal''; otherwise, we say it is +``orphaned''. For a normal @code{TARGET_EXPR} the temporary variable +should be treated as an alias for the left-hand side of the assignment, +rather than as a new temporary variable. + +The third operand to the @code{TARGET_EXPR}, if present, is a +cleanup-expression (i.e., destructor call) for the temporary. If this +expression is orphaned, then this expression must be executed when the +statement containing this expression is complete. These cleanups must +always be executed in the order opposite to that in which they were +encountered. Note that if a temporary is created on one branch of a +conditional operator (i.e., in the second or third operand to a +@code{COND_EXPR}), the cleanup must be run only if that branch is +actually executed. + +See @code{STMT_IS_FULL_EXPR_P} for more information about running these +cleanups. + +@item AGGR_INIT_EXPR +An @code{AGGR_INIT_EXPR} represents the initialization as the return +value of a function call, or as the result of a constructor. An +@code{AGGR_INIT_EXPR} will only appear as a full-expression, or as the +second operand of a @code{TARGET_EXPR}. The first operand to the +@code{AGGR_INIT_EXPR} is the address of a function to call, just as in +a @code{CALL_EXPR}. The second operand are the arguments to pass that +function, as a @code{TREE_LIST}, again in a manner similar to that of +a @code{CALL_EXPR}. + +If @code{AGGR_INIT_VIA_CTOR_P} holds of the @code{AGGR_INIT_EXPR}, then +the initialization is via a constructor call. The address of the third +operand of the @code{AGGR_INIT_EXPR}, which is always a @code{VAR_DECL}, +is taken, and this value replaces the first argument in the argument +list. + +In either case, the expression is void. + +@item VA_ARG_EXPR +This node is used to implement support for the C/C++ variable argument-list +mechanism. It represents expressions like @code{va_arg (ap, type)}. +Its @code{TREE_TYPE} yields the tree representation for @code{type} and +its sole argument yields the representation for @code{ap}. + +@item OMP_PARALLEL + +Represents @code{#pragma omp parallel [clause1 ... clauseN]}. It +has four operands: + +Operand @code{OMP_PARALLEL_BODY} is valid while in GENERIC and +High GIMPLE forms. It contains the body of code to be executed +by all the threads. During GIMPLE lowering, this operand becomes +@code{NULL} and the body is emitted linearly after +@code{OMP_PARALLEL}. + +Operand @code{OMP_PARALLEL_CLAUSES} is the list of clauses +associated with the directive. + +Operand @code{OMP_PARALLEL_FN} is created by +@code{pass_lower_omp}, it contains the @code{FUNCTION_DECL} +for the function that will contain the body of the parallel +region. + +Operand @code{OMP_PARALLEL_DATA_ARG} is also created by +@code{pass_lower_omp}. If there are shared variables to be +communicated to the children threads, this operand will contain +the @code{VAR_DECL} that contains all the shared values and +variables. + +@item OMP_FOR + +Represents @code{#pragma omp for [clause1 ... clauseN]}. It +has 5 operands: + +Operand @code{OMP_FOR_BODY} contains the loop body. + +Operand @code{OMP_FOR_CLAUSES} is the list of clauses +associated with the directive. + +Operand @code{OMP_FOR_INIT} is the loop initialization code of +the form @code{VAR = N1}. + +Operand @code{OMP_FOR_COND} is the loop conditional expression +of the form @code{VAR @{<,>,<=,>=@} N2}. + +Operand @code{OMP_FOR_INCR} is the loop index increment of the +form @code{VAR @{+=,-=@} INCR}. + +Operand @code{OMP_FOR_PRE_BODY} contains side-effect code from +operands @code{OMP_FOR_INIT}, @code{OMP_FOR_COND} and +@code{OMP_FOR_INC}. These side-effects are part of the +@code{OMP_FOR} block but must be evaluated before the start of +loop body. + +The loop index variable @code{VAR} must be a signed integer variable, +which is implicitly private to each thread. Bounds +@code{N1} and @code{N2} and the increment expression +@code{INCR} are required to be loop invariant integer +expressions that are evaluated without any synchronization. The +evaluation order, frequency of evaluation and side-effects are +unspecified by the standard. + +@item OMP_SECTIONS + +Represents @code{#pragma omp sections [clause1 ... clauseN]}. + +Operand @code{OMP_SECTIONS_BODY} contains the sections body, +which in turn contains a set of @code{OMP_SECTION} nodes for +each of the concurrent sections delimited by @code{#pragma omp +section}. + +Operand @code{OMP_SECTIONS_CLAUSES} is the list of clauses +associated with the directive. + +@item OMP_SECTION + +Section delimiter for @code{OMP_SECTIONS}. + +@item OMP_SINGLE + +Represents @code{#pragma omp single}. + +Operand @code{OMP_SINGLE_BODY} contains the body of code to be +executed by a single thread. + +Operand @code{OMP_SINGLE_CLAUSES} is the list of clauses +associated with the directive. + +@item OMP_MASTER + +Represents @code{#pragma omp master}. + +Operand @code{OMP_MASTER_BODY} contains the body of code to be +executed by the master thread. + +@item OMP_ORDERED + +Represents @code{#pragma omp ordered}. + +Operand @code{OMP_ORDERED_BODY} contains the body of code to be +executed in the sequential order dictated by the loop index +variable. + +@item OMP_CRITICAL + +Represents @code{#pragma omp critical [name]}. + +Operand @code{OMP_CRITICAL_BODY} is the critical section. + +Operand @code{OMP_CRITICAL_NAME} is an optional identifier to +label the critical section. + +@item OMP_RETURN + +This does not represent any OpenMP directive, it is an artificial +marker to indicate the end of the body of an OpenMP. It is used +by the flow graph (@code{tree-cfg.c}) and OpenMP region +building code (@code{omp-low.c}). + +@item OMP_CONTINUE + +Similarly, this instruction does not represent an OpenMP +directive, it is used by @code{OMP_FOR} and +@code{OMP_SECTIONS} to mark the place where the code needs to +loop to the next iteration (in the case of @code{OMP_FOR}) or +the next section (in the case of @code{OMP_SECTIONS}). + +In some cases, @code{OMP_CONTINUE} is placed right before +@code{OMP_RETURN}. But if there are cleanups that need to +occur right after the looping body, it will be emitted between +@code{OMP_CONTINUE} and @code{OMP_RETURN}. + +@item OMP_ATOMIC + +Represents @code{#pragma omp atomic}. + +Operand 0 is the address at which the atomic operation is to be +performed. + +Operand 1 is the expression to evaluate. The gimplifier tries +three alternative code generation strategies. Whenever possible, +an atomic update built-in is used. If that fails, a +compare-and-swap loop is attempted. If that also fails, a +regular critical section around the expression is used. + +@item OMP_CLAUSE + +Represents clauses associated with one of the @code{OMP_} directives. +Clauses are represented by separate sub-codes defined in +@file{tree.h}. Clauses codes can be one of: +@code{OMP_CLAUSE_PRIVATE}, @code{OMP_CLAUSE_SHARED}, +@code{OMP_CLAUSE_FIRSTPRIVATE}, +@code{OMP_CLAUSE_LASTPRIVATE}, @code{OMP_CLAUSE_COPYIN}, +@code{OMP_CLAUSE_COPYPRIVATE}, @code{OMP_CLAUSE_IF}, +@code{OMP_CLAUSE_NUM_THREADS}, @code{OMP_CLAUSE_SCHEDULE}, +@code{OMP_CLAUSE_NOWAIT}, @code{OMP_CLAUSE_ORDERED}, +@code{OMP_CLAUSE_DEFAULT}, and @code{OMP_CLAUSE_REDUCTION}. Each code +represents the corresponding OpenMP clause. + +Clauses associated with the same directive are chained together +via @code{OMP_CLAUSE_CHAIN}. Those clauses that accept a list +of variables are restricted to exactly one, accessed with +@code{OMP_CLAUSE_VAR}. Therefore, multiple variables under the +same clause @code{C} need to be represented as multiple @code{C} clauses +chained together. This facilitates adding new clauses during +compilation. + +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/cfg.texi b/gcc-4.2.1-5666.3/gcc/doc/cfg.texi new file mode 100644 index 000000000..68b8063f9 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/cfg.texi @@ -0,0 +1,666 @@ +@c -*-texinfo-*- +@c Copyright (C) 2001, 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Control Flow Graph +@c --------------------------------------------------------------------- + +@node Control Flow +@chapter Control Flow Graph +@cindex CFG, Control Flow Graph +@findex basic-block.h + +A control flow graph (CFG) is a data structure built on top of the +intermediate code representation (the RTL or @code{tree} instruction +stream) abstracting the control flow behavior of a function that is +being compiled. The CFG is a directed graph where the vertices +represent basic blocks and edges represent possible transfer of +control flow from one basic block to another. The data structures +used to represent the control flow graph are defined in +@file{basic-block.h}. + +@menu +* Basic Blocks:: The definition and representation of basic blocks. +* Edges:: Types of edges and their representation. +* Profile information:: Representation of frequencies and probabilities. +* Maintaining the CFG:: Keeping the control flow graph and up to date. +* Liveness information:: Using and maintaining liveness information. +@end menu + + +@node Basic Blocks +@section Basic Blocks + +@cindex basic block +@findex basic_block +A basic block is a straight-line sequence of code with only one entry +point and only one exit. In GCC, basic blocks are represented using +the @code{basic_block} data type. + +@findex next_bb, prev_bb, FOR_EACH_BB +Two pointer members of the @code{basic_block} structure are the +pointers @code{next_bb} and @code{prev_bb}. These are used to keep +doubly linked chain of basic blocks in the same order as the +underlying instruction stream. The chain of basic blocks is updated +transparently by the provided API for manipulating the CFG@. The macro +@code{FOR_EACH_BB} can be used to visit all the basic blocks in +lexicographical order. Dominator traversals are also possible using +@code{walk_dominator_tree}. Given two basic blocks A and B, block A +dominates block B if A is @emph{always} executed before B@. + +@findex BASIC_BLOCK +The @code{BASIC_BLOCK} array contains all basic blocks in an +unspecified order. Each @code{basic_block} structure has a field +that holds a unique integer identifier @code{index} that is the +index of the block in the @code{BASIC_BLOCK} array. +The total number of basic blocks in the function is +@code{n_basic_blocks}. Both the basic block indices and +the total number of basic blocks may vary during the compilation +process, as passes reorder, create, duplicate, and destroy basic +blocks. The index for any block should never be greater than +@code{last_basic_block}. + +@findex ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR +Special basic blocks represent possible entry and exit points of a +function. These blocks are called @code{ENTRY_BLOCK_PTR} and +@code{EXIT_BLOCK_PTR}. These blocks do not contain any code, and are +not elements of the @code{BASIC_BLOCK} array. Therefore they have +been assigned unique, negative index numbers. + +Each @code{basic_block} also contains pointers to the first +instruction (the @dfn{head}) and the last instruction (the @dfn{tail}) +or @dfn{end} of the instruction stream contained in a basic block. In +fact, since the @code{basic_block} data type is used to represent +blocks in both major intermediate representations of GCC (@code{tree} +and RTL), there are pointers to the head and end of a basic block for +both representations. + +@findex NOTE_INSN_BASIC_BLOCK, CODE_LABEL, notes +For RTL, these pointers are @code{rtx head, end}. In the RTL function +representation, the head pointer always points either to a +@code{NOTE_INSN_BASIC_BLOCK} or to a @code{CODE_LABEL}, if present. +In the RTL representation of a function, the instruction stream +contains not only the ``real'' instructions, but also @dfn{notes}. +Any function that moves or duplicates the basic blocks needs +to take care of updating of these notes. Many of these notes expect +that the instruction stream consists of linear regions, making such +updates difficult. The @code{NOTE_INSN_BASIC_BLOCK} note is the only +kind of note that may appear in the instruction stream contained in a +basic block. The instruction stream of a basic block always follows a +@code{NOTE_INSN_BASIC_BLOCK}, but zero or more @code{CODE_LABEL} +nodes can precede the block note. A basic block ends by control flow +instruction or last instruction before following @code{CODE_LABEL} or +@code{NOTE_INSN_BASIC_BLOCK}. A @code{CODE_LABEL} cannot appear in +the instruction stream of a basic block. + +@findex can_fallthru +@cindex table jump +In addition to notes, the jump table vectors are also represented as +``pseudo-instructions'' inside the insn stream. These vectors never +appear in the basic block and should always be placed just after the +table jump instructions referencing them. After removing the +table-jump it is often difficult to eliminate the code computing the +address and referencing the vector, so cleaning up these vectors is +postponed until after liveness analysis. Thus the jump table vectors +may appear in the insn stream unreferenced and without any purpose. +Before any edge is made @dfn{fall-thru}, the existence of such +construct in the way needs to be checked by calling +@code{can_fallthru} function. + +@cindex block statement iterators +For the @code{tree} representation, the head and end of the basic block +are being pointed to by the @code{stmt_list} field, but this special +@code{tree} should never be referenced directly. Instead, at the tree +level abstract containers and iterators are used to access statements +and expressions in basic blocks. These iterators are called +@dfn{block statement iterators} (BSIs). Grep for @code{^bsi} +in the various @file{tree-*} files. +The following snippet will pretty-print all the statements of the +program in the GIMPLE representation. + +@smallexample +FOR_EACH_BB (bb) + @{ + block_stmt_iterator si; + + for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) + @{ + tree stmt = bsi_stmt (si); + print_generic_stmt (stderr, stmt, 0); + @} + @} +@end smallexample + + +@node Edges +@section Edges + +@cindex edge in the flow graph +@findex edge +Edges represent possible control flow transfers from the end of some +basic block A to the head of another basic block B@. We say that A is +a predecessor of B, and B is a successor of A@. Edges are represented +in GCC with the @code{edge} data type. Each @code{edge} acts as a +link between two basic blocks: the @code{src} member of an edge +points to the predecessor basic block of the @code{dest} basic block. +The members @code{preds} and @code{succs} of the @code{basic_block} data +type point to type-safe vectors of edges to the predecessors and +successors of the block. + +@cindex edge iterators +When walking the edges in an edge vector, @dfn{edge iterators} should +be used. Edge iterators are constructed using the +@code{edge_iterator} data structure and several methods are available +to operate on them: + +@ftable @code +@item ei_start +This function initializes an @code{edge_iterator} that points to the +first edge in a vector of edges. + +@item ei_last +This function initializes an @code{edge_iterator} that points to the +last edge in a vector of edges. + +@item ei_end_p +This predicate is @code{true} if an @code{edge_iterator} represents +the last edge in an edge vector. + +@item ei_one_before_end_p +This predicate is @code{true} if an @code{edge_iterator} represents +the second last edge in an edge vector. + +@item ei_next +This function takes a pointer to an @code{edge_iterator} and makes it +point to the next edge in the sequence. + +@item ei_prev +This function takes a pointer to an @code{edge_iterator} and makes it +point to the previous edge in the sequence. + +@item ei_edge +This function returns the @code{edge} currently pointed to by an +@code{edge_iterator}. + +@item ei_safe_safe +This function returns the @code{edge} currently pointed to by an +@code{edge_iterator}, but returns @code{NULL} if the iterator is +pointing at the end of the sequence. This function has been provided +for existing code makes the assumption that a @code{NULL} edge +indicates the end of the sequence. + +@end ftable + +The convenience macro @code{FOR_EACH_EDGE} can be used to visit all of +the edges in a sequence of predecessor or successor edges. It must +not be used when an element might be removed during the traversal, +otherwise elements will be missed. Here is an example of how to use +the macro: + +@smallexample +edge e; +edge_iterator ei; + +FOR_EACH_EDGE (e, ei, bb->succs) + @{ + if (e->flags & EDGE_FALLTHRU) + break; + @} +@end smallexample + +@findex fall-thru +There are various reasons why control flow may transfer from one block +to another. One possibility is that some instruction, for example a +@code{CODE_LABEL}, in a linearized instruction stream just always +starts a new basic block. In this case a @dfn{fall-thru} edge links +the basic block to the first following basic block. But there are +several other reasons why edges may be created. The @code{flags} +field of the @code{edge} data type is used to store information +about the type of edge we are dealing with. Each edge is of one of +the following types: + +@table @emph +@item jump +No type flags are set for edges corresponding to jump instructions. +These edges are used for unconditional or conditional jumps and in +RTL also for table jumps. They are the easiest to manipulate as they +may be freely redirected when the flow graph is not in SSA form. + +@item fall-thru +@findex EDGE_FALLTHRU, force_nonfallthru +Fall-thru edges are present in case where the basic block may continue +execution to the following one without branching. These edges have +the @code{EDGE_FALLTHRU} flag set. Unlike other types of edges, these +edges must come into the basic block immediately following in the +instruction stream. The function @code{force_nonfallthru} is +available to insert an unconditional jump in the case that redirection +is needed. Note that this may require creation of a new basic block. + +@item exception handling +@cindex exception handling +@findex EDGE_ABNORMAL, EDGE_EH +Exception handling edges represent possible control transfers from a +trapping instruction to an exception handler. The definition of +``trapping'' varies. In C++, only function calls can throw, but for +Java, exceptions like division by zero or segmentation fault are +defined and thus each instruction possibly throwing this kind of +exception needs to be handled as control flow instruction. Exception +edges have the @code{EDGE_ABNORMAL} and @code{EDGE_EH} flags set. + +@findex purge_dead_edges +When updating the instruction stream it is easy to change possibly +trapping instruction to non-trapping, by simply removing the exception +edge. The opposite conversion is difficult, but should not happen +anyway. The edges can be eliminated via @code{purge_dead_edges} call. + +@findex REG_EH_REGION, EDGE_ABNORMAL_CALL +In the RTL representation, the destination of an exception edge is +specified by @code{REG_EH_REGION} note attached to the insn. +In case of a trapping call the @code{EDGE_ABNORMAL_CALL} flag is set +too. In the @code{tree} representation, this extra flag is not set. + +@findex may_trap_p, tree_could_trap_p +In the RTL representation, the predicate @code{may_trap_p} may be used +to check whether instruction still may trap or not. For the tree +representation, the @code{tree_could_trap_p} predicate is available, +but this predicate only checks for possible memory traps, as in +dereferencing an invalid pointer location. + + +@item sibling calls +@cindex sibling call +@findex EDGE_ABNORMAL, EDGE_SIBCALL +Sibling calls or tail calls terminate the function in a non-standard +way and thus an edge to the exit must be present. +@code{EDGE_SIBCALL} and @code{EDGE_ABNORMAL} are set in such case. +These edges only exist in the RTL representation. + +@item computed jumps +@cindex computed jump +@findex EDGE_ABNORMAL +Computed jumps contain edges to all labels in the function referenced +from the code. All those edges have @code{EDGE_ABNORMAL} flag set. +The edges used to represent computed jumps often cause compile time +performance problems, since functions consisting of many taken labels +and many computed jumps may have @emph{very} dense flow graphs, so +these edges need to be handled with special care. During the earlier +stages of the compilation process, GCC tries to avoid such dense flow +graphs by factoring computed jumps. For example, given the following +series of jumps, + +@smallexample + goto *x; + [ ... ] + + goto *x; + [ ... ] + + goto *x; + [ ... ] +@end smallexample + +@noindent +factoring the computed jumps results in the following code sequence +which has a much simpler flow graph: + +@smallexample + goto y; + [ ... ] + + goto y; + [ ... ] + + goto y; + [ ... ] + +y: + goto *x; +@end smallexample + +However, the classic problem with this transformation is that it has a +runtime cost in there resulting code: An extra jump. Therefore, the +computed jumps are un-factored in the later passes of the compiler. +Be aware of that when you work on passes in that area. There have +been numerous examples already where the compile time for code with +unfactored computed jumps caused some serious headaches. + +@item nonlocal goto handlers +@cindex nonlocal goto handler +@findex EDGE_ABNORMAL, EDGE_ABNORMAL_CALL +GCC allows nested functions to return into caller using a @code{goto} +to a label passed to as an argument to the callee. The labels passed +to nested functions contain special code to cleanup after function +call. Such sections of code are referred to as ``nonlocal goto +receivers''. If a function contains such nonlocal goto receivers, an +edge from the call to the label is created with the +@code{EDGE_ABNORMAL} and @code{EDGE_ABNORMAL_CALL} flags set. + +@item function entry points +@cindex function entry point, alternate function entry point +@findex LABEL_ALTERNATE_NAME +By definition, execution of function starts at basic block 0, so there +is always an edge from the @code{ENTRY_BLOCK_PTR} to basic block 0. +There is no @code{tree} representation for alternate entry points at +this moment. In RTL, alternate entry points are specified by +@code{CODE_LABEL} with @code{LABEL_ALTERNATE_NAME} defined. This +feature is currently used for multiple entry point prologues and is +limited to post-reload passes only. This can be used by back-ends to +emit alternate prologues for functions called from different contexts. +In future full support for multiple entry functions defined by Fortran +90 needs to be implemented. + +@item function exits +In the pre-reload representation a function terminates after the last +instruction in the insn chain and no explicit return instructions are +used. This corresponds to the fall-thru edge into exit block. After +reload, optimal RTL epilogues are used that use explicit (conditional) +return instructions that are represented by edges with no flags set. + +@end table + + +@node Profile information +@section Profile information + +@cindex profile representation +In many cases a compiler must make a choice whether to trade speed in +one part of code for speed in another, or to trade code size for code +speed. In such cases it is useful to know information about how often +some given block will be executed. That is the purpose for +maintaining profile within the flow graph. +GCC can handle profile information obtained through @dfn{profile +feedback}, but it can also estimate branch probabilities based on +statics and heuristics. + +@cindex profile feedback +The feedback based profile is produced by compiling the program with +instrumentation, executing it on a train run and reading the numbers +of executions of basic blocks and edges back to the compiler while +re-compiling the program to produce the final executable. This method +provides very accurate information about where a program spends most +of its time on the train run. Whether it matches the average run of +course depends on the choice of train data set, but several studies +have shown that the behavior of a program usually changes just +marginally over different data sets. + +@cindex Static profile estimation +@cindex branch prediction +@findex predict.def +When profile feedback is not available, the compiler may be asked to +attempt to predict the behavior of each branch in the program using a +set of heuristics (see @file{predict.def} for details) and compute +estimated frequencies of each basic block by propagating the +probabilities over the graph. + +@findex frequency, count, BB_FREQ_BASE +Each @code{basic_block} contains two integer fields to represent +profile information: @code{frequency} and @code{count}. The +@code{frequency} is an estimation how often is basic block executed +within a function. It is represented as an integer scaled in the +range from 0 to @code{BB_FREQ_BASE}. The most frequently executed +basic block in function is initially set to @code{BB_FREQ_BASE} and +the rest of frequencies are scaled accordingly. During optimization, +the frequency of the most frequent basic block can both decrease (for +instance by loop unrolling) or grow (for instance by cross-jumping +optimization), so scaling sometimes has to be performed multiple +times. + +@findex gcov_type +The @code{count} contains hard-counted numbers of execution measured +during training runs and is nonzero only when profile feedback is +available. This value is represented as the host's widest integer +(typically a 64 bit integer) of the special type @code{gcov_type}. + +Most optimization passes can use only the frequency information of a +basic block, but a few passes may want to know hard execution counts. +The frequencies should always match the counts after scaling, however +during updating of the profile information numerical error may +accumulate into quite large errors. + +@findex REG_BR_PROB_BASE, EDGE_FREQUENCY +Each edge also contains a branch probability field: an integer in the +range from 0 to @code{REG_BR_PROB_BASE}. It represents probability of +passing control from the end of the @code{src} basic block to the +@code{dest} basic block, i.e.@: the probability that control will flow +along this edge. The @code{EDGE_FREQUENCY} macro is available to +compute how frequently a given edge is taken. There is a @code{count} +field for each edge as well, representing same information as for a +basic block. + +The basic block frequencies are not represented in the instruction +stream, but in the RTL representation the edge frequencies are +represented for conditional jumps (via the @code{REG_BR_PROB} +macro) since they are used when instructions are output to the +assembly file and the flow graph is no longer maintained. + +@cindex reverse probability +The probability that control flow arrives via a given edge to its +destination basic block is called @dfn{reverse probability} and is not +directly represented, but it may be easily computed from frequencies +of basic blocks. + +@findex redirect_edge_and_branch +Updating profile information is a delicate task that can unfortunately +not be easily integrated with the CFG manipulation API@. Many of the +functions and hooks to modify the CFG, such as +@code{redirect_edge_and_branch}, do not have enough information to +easily update the profile, so updating it is in the majority of cases +left up to the caller. It is difficult to uncover bugs in the profile +updating code, because they manifest themselves only by producing +worse code, and checking profile consistency is not possible because +of numeric error accumulation. Hence special attention needs to be +given to this issue in each pass that modifies the CFG@. + +@findex REG_BR_PROB_BASE, BB_FREQ_BASE, count +It is important to point out that @code{REG_BR_PROB_BASE} and +@code{BB_FREQ_BASE} are both set low enough to be possible to compute +second power of any frequency or probability in the flow graph, it is +not possible to even square the @code{count} field, as modern CPUs are +fast enough to execute $2^32$ operations quickly. + + +@node Maintaining the CFG +@section Maintaining the CFG +@findex cfghooks.h + +An important task of each compiler pass is to keep both the control +flow graph and all profile information up-to-date. Reconstruction of +the control flow graph after each pass is not an option, since it may be +very expensive and lost profile information cannot be reconstructed at +all. + +GCC has two major intermediate representations, and both use the +@code{basic_block} and @code{edge} data types to represent control +flow. Both representations share as much of the CFG maintenance code +as possible. For each representation, a set of @dfn{hooks} is defined +so that each representation can provide its own implementation of CFG +manipulation routines when necessary. These hooks are defined in +@file{cfghooks.h}. There are hooks for almost all common CFG +manipulations, including block splitting and merging, edge redirection +and creating and deleting basic blocks. These hooks should provide +everything you need to maintain and manipulate the CFG in both the RTL +and @code{tree} representation. + +At the moment, the basic block boundaries are maintained transparently +when modifying instructions, so there rarely is a need to move them +manually (such as in case someone wants to output instruction outside +basic block explicitly). +Often the CFG may be better viewed as integral part of instruction +chain, than structure built on the top of it. However, in principle +the control flow graph for the @code{tree} representation is +@emph{not} an integral part of the representation, in that a function +tree may be expanded without first building a flow graph for the +@code{tree} representation at all. This happens when compiling +without any @code{tree} optimization enabled. When the @code{tree} +optimizations are enabled and the instruction stream is rewritten in +SSA form, the CFG is very tightly coupled with the instruction stream. +In particular, statement insertion and removal has to be done with +care. In fact, the whole @code{tree} representation can not be easily +used or maintained without proper maintenance of the CFG +simultaneously. + +@findex BLOCK_FOR_INSN, bb_for_stmt +In the RTL representation, each instruction has a +@code{BLOCK_FOR_INSN} value that represents pointer to the basic block +that contains the instruction. In the @code{tree} representation, the +function @code{bb_for_stmt} returns a pointer to the basic block +containing the queried statement. + +@cindex block statement iterators +When changes need to be applied to a function in its @code{tree} +representation, @dfn{block statement iterators} should be used. These +iterators provide an integrated abstraction of the flow graph and the +instruction stream. Block statement iterators iterators are +constructed using the @code{block_stmt_iterator} data structure and +several modifier are available, including the following: + +@ftable @code +@item bsi_start +This function initializes a @code{block_stmt_iterator} that points to +the first non-empty statement in a basic block. + +@item bsi_last +This function initializes a @code{block_stmt_iterator} that points to +the last statement in a basic block. + +@item bsi_end_p +This predicate is @code{true} if a @code{block_stmt_iterator} +represents the end of a basic block. + +@item bsi_next +This function takes a @code{block_stmt_iterator} and makes it point to +its successor. + +@item bsi_prev +This function takes a @code{block_stmt_iterator} and makes it point to +its predecessor. + +@item bsi_insert_after +This function inserts a statement after the @code{block_stmt_iterator} +passed in. The final parameter determines whether the statement +iterator is updated to point to the newly inserted statement, or left +pointing to the original statement. + +@item bsi_insert_before +This function inserts a statement before the @code{block_stmt_iterator} +passed in. The final parameter determines whether the statement +iterator is updated to point to the newly inserted statement, or left +pointing to the original statement. + +@item bsi_remove +This function removes the @code{block_stmt_iterator} passed in and +rechains the remaining statements in a basic block, if any. +@end ftable + +@findex BB_HEAD, BB_END +In the RTL representation, the macros @code{BB_HEAD} and @code{BB_END} +may be used to get the head and end @code{rtx} of a basic block. No +abstract iterators are defined for traversing the insn chain, but you +can just use @code{NEXT_INSN} and @code{PREV_INSN} instead. See +@xref{Insns}. + +@findex purge_dead_edges +Usually a code manipulating pass simplifies the instruction stream and +the flow of control, possibly eliminating some edges. This may for +example happen when a conditional jump is replaced with an +unconditional jump, but also when simplifying possibly trapping +instruction to non-trapping while compiling Java. Updating of edges +is not transparent and each optimization pass is required to do so +manually. However only few cases occur in practice. The pass may +call @code{purge_dead_edges} on a given basic block to remove +superfluous edges, if any. + +@findex redirect_edge_and_branch, redirect_jump +Another common scenario is redirection of branch instructions, but +this is best modeled as redirection of edges in the control flow graph +and thus use of @code{redirect_edge_and_branch} is preferred over more +low level functions, such as @code{redirect_jump} that operate on RTL +chain only. The CFG hooks defined in @file{cfghooks.h} should provide +the complete API required for manipulating and maintaining the CFG@. + +@findex split_block +It is also possible that a pass has to insert control flow instruction +into the middle of a basic block, thus creating an entry point in the +middle of the basic block, which is impossible by definition: The +block must be split to make sure it only has one entry point, i.e.@: the +head of the basic block. The CFG hook @code{split_block} may be used +when an instruction in the middle of a basic block has to become the +target of a jump or branch instruction. + +@findex insert_insn_on_edge +@findex commit_edge_insertions +@findex bsi_insert_on_edge +@findex bsi_commit_edge_inserts +@cindex edge splitting +For a global optimizer, a common operation is to split edges in the +flow graph and insert instructions on them. In the RTL +representation, this can be easily done using the +@code{insert_insn_on_edge} function that emits an instruction +``on the edge'', caching it for a later @code{commit_edge_insertions} +call that will take care of moving the inserted instructions off the +edge into the instruction stream contained in a basic block. This +includes the creation of new basic blocks where needed. In the +@code{tree} representation, the equivalent functions are +@code{bsi_insert_on_edge} which inserts a block statement +iterator on an edge, and @code{bsi_commit_edge_inserts} which flushes +the instruction to actual instruction stream. + +While debugging the optimization pass, an @code{verify_flow_info} +function may be useful to find bugs in the control flow graph updating +code. + +Note that at present, the representation of control flow in the +@code{tree} representation is discarded before expanding to RTL@. +Long term the CFG should be maintained and ``expanded'' to the +RTL representation along with the function @code{tree} itself. + + +@node Liveness information +@section Liveness information +@cindex Liveness representation +Liveness information is useful to determine whether some register is +``live'' at given point of program, i.e.@: that it contains a value that +may be used at a later point in the program. This information is +used, for instance, during register allocation, as the pseudo +registers only need to be assigned to a unique hard register or to a +stack slot if they are live. The hard registers and stack slots may +be freely reused for other values when a register is dead. + +@findex REG_DEAD, REG_UNUSED +The liveness information is stored partly in the RTL instruction +stream and partly in the flow graph. Local information is stored in +the instruction stream: +Each instruction may contain @code{REG_DEAD} notes representing that +the value of a given register is no longer needed, or +@code{REG_UNUSED} notes representing that the value computed by the +instruction is never used. The second is useful for instructions +computing multiple values at once. + +@findex global_live_at_start, global_live_at_end +Global liveness information is stored in the control flow graph. +Each basic block contains two bitmaps, @code{global_live_at_start} and +@code{global_live_at_end} representing liveness of each register at +the entry and exit of the basic block. The file @code{flow.c} +contains functions to compute liveness of each register at any given +place in the instruction stream using this information. + +@findex BB_DIRTY, clear_bb_flags, update_life_info_in_dirty_blocks +Liveness is expensive to compute and thus it is desirable to keep it +up to date during code modifying passes. This can be easily +accomplished using the @code{flags} field of a basic block. Functions +modifying the instruction stream automatically set the @code{BB_DIRTY} +flag of a modifies basic block, so the pass may simply +use@code{clear_bb_flags} before doing any modifications and then ask +the data flow module to have liveness updated via the +@code{update_life_info_in_dirty_blocks} function. + +This scheme works reliably as long as no control flow graph +transformations are done. The task of updating liveness after control +flow graph changes is more difficult as normal iterative data flow +analysis may produce invalid results or get into an infinite cycle +when the initial solution is not below the desired one. Only simple +transformations, like splitting basic blocks or inserting on edges, +are safe, as functions to implement them already know how to update +liveness information locally. diff --git a/gcc-4.2.1-5666.3/gcc/doc/collect2.texi b/gcc-4.2.1-5666.3/gcc/doc/collect2.texi new file mode 100644 index 000000000..c3498c531 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/collect2.texi @@ -0,0 +1,85 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Collect2 +@chapter @code{collect2} + +GCC uses a utility called @code{collect2} on nearly all systems to arrange +to call various initialization functions at start time. + +The program @code{collect2} works by linking the program once and +looking through the linker output file for symbols with particular names +indicating they are constructor functions. If it finds any, it +creates a new temporary @samp{.c} file containing a table of them, +compiles it, and links the program a second time including that file. + +@findex __main +@cindex constructors, automatic calls +The actual calls to the constructors are carried out by a subroutine +called @code{__main}, which is called (automatically) at the beginning +of the body of @code{main} (provided @code{main} was compiled with GNU +CC)@. Calling @code{__main} is necessary, even when compiling C code, to +allow linking C and C++ object code together. (If you use +@option{-nostdlib}, you get an unresolved reference to @code{__main}, +since it's defined in the standard GCC library. Include @option{-lgcc} at +the end of your compiler command line to resolve this reference.) + +The program @code{collect2} is installed as @code{ld} in the directory +where the passes of the compiler are installed. When @code{collect2} +needs to find the @emph{real} @code{ld}, it tries the following file +names: + +@itemize @bullet +@item +@file{real-ld} in the directories listed in the compiler's search +directories. + +@item +@file{real-ld} in the directories listed in the environment variable +@code{PATH}. + +@item +The file specified in the @code{REAL_LD_FILE_NAME} configuration macro, +if specified. + +@item +@file{ld} in the compiler's search directories, except that +@code{collect2} will not execute itself recursively. + +@item +@file{ld} in @code{PATH}. +@end itemize + +``The compiler's search directories'' means all the directories where +@command{gcc} searches for passes of the compiler. This includes +directories that you specify with @option{-B}. + +Cross-compilers search a little differently: + +@itemize @bullet +@item +@file{real-ld} in the compiler's search directories. + +@item +@file{@var{target}-real-ld} in @code{PATH}. + +@item +The file specified in the @code{REAL_LD_FILE_NAME} configuration macro, +if specified. + +@item +@file{ld} in the compiler's search directories. + +@item +@file{@var{target}-ld} in @code{PATH}. +@end itemize + +@code{collect2} explicitly avoids running @code{ld} using the file name +under which @code{collect2} itself was invoked. In fact, it remembers +up a list of such names---in case one copy of @code{collect2} finds +another copy (or version) of @code{collect2} installed as @code{ld} in a +second place in the search path. + +@code{collect2} searches for the utilities @code{nm} and @code{strip} +using the same algorithm as above for @code{ld}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/compat.texi b/gcc-4.2.1-5666.3/gcc/doc/compat.texi new file mode 100644 index 000000000..4e65b4582 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/compat.texi @@ -0,0 +1,156 @@ +@c Copyright (C) 2002, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Compatibility +@chapter Binary Compatibility +@cindex binary compatibility +@cindex ABI +@cindex application binary interface + +Binary compatibility encompasses several related concepts: + +@table @dfn +@item application binary interface (ABI) +The set of runtime conventions followed by all of the tools that deal +with binary representations of a program, including compilers, assemblers, +linkers, and language runtime support. +Some ABIs are formal with a written specification, possibly designed +by multiple interested parties. Others are simply the way things are +actually done by a particular set of tools. + +@item ABI conformance +A compiler conforms to an ABI if it generates code that follows all of +the specifications enumerated by that ABI@. +A library conforms to an ABI if it is implemented according to that ABI@. +An application conforms to an ABI if it is built using tools that conform +to that ABI and does not contain source code that specifically changes +behavior specified by the ABI@. + +@item calling conventions +Calling conventions are a subset of an ABI that specify of how arguments +are passed and function results are returned. + +@item interoperability +Different sets of tools are interoperable if they generate files that +can be used in the same program. The set of tools includes compilers, +assemblers, linkers, libraries, header files, startup files, and debuggers. +Binaries produced by different sets of tools are not interoperable unless +they implement the same ABI@. This applies to different versions of the +same tools as well as tools from different vendors. + +@item intercallability +Whether a function in a binary built by one set of tools can call a +function in a binary built by a different set of tools is a subset +of interoperability. + +@item implementation-defined features +Language standards include lists of implementation-defined features whose +behavior can vary from one implementation to another. Some of these +features are normally covered by a platform's ABI and others are not. +The features that are not covered by an ABI generally affect how a +program behaves, but not intercallability. + +@item compatibility +Conformance to the same ABI and the same behavior of implementation-defined +features are both relevant for compatibility. +@end table + +The application binary interface implemented by a C or C++ compiler +affects code generation and runtime support for: + +@itemize @bullet +@item +size and alignment of data types +@item +layout of structured types +@item +calling conventions +@item +register usage conventions +@item +interfaces for runtime arithmetic support +@item +object file formats +@end itemize + +In addition, the application binary interface implemented by a C++ compiler +affects code generation and runtime support for: +@itemize @bullet +@item +name mangling +@item +exception handling +@item +invoking constructors and destructors +@item +layout, alignment, and padding of classes +@item +layout and alignment of virtual tables +@end itemize + +Some GCC compilation options cause the compiler to generate code that +does not conform to the platform's default ABI@. Other options cause +different program behavior for implementation-defined features that are +not covered by an ABI@. These options are provided for consistency with +other compilers that do not follow the platform's default ABI or the +usual behavior of implementation-defined features for the platform. +Be very careful about using such options. + +Most platforms have a well-defined ABI that covers C code, but ABIs +that cover C++ functionality are not yet common. + +Starting with GCC 3.2, GCC binary conventions for C++ are based on a +written, vendor-neutral C++ ABI that was designed to be specific to +64-bit Itanium but also includes generic specifications that apply to +any platform. +This C++ ABI is also implemented by other compiler vendors on some +platforms, notably GNU/Linux and BSD systems. +We have tried hard to provide a stable ABI that will be compatible with +future GCC releases, but it is possible that we will encounter problems +that make this difficult. Such problems could include different +interpretations of the C++ ABI by different vendors, bugs in the ABI, or +bugs in the implementation of the ABI in different compilers. +GCC's @option{-Wabi} switch warns when G++ generates code that is +probably not compatible with the C++ ABI@. + +The C++ library used with a C++ compiler includes the Standard C++ +Library, with functionality defined in the C++ Standard, plus language +runtime support. The runtime support is included in a C++ ABI, but there +is no formal ABI for the Standard C++ Library. Two implementations +of that library are interoperable if one follows the de-facto ABI of the +other and if they are both built with the same compiler, or with compilers +that conform to the same ABI for C++ compiler and runtime support. + +When G++ and another C++ compiler conform to the same C++ ABI, but the +implementations of the Standard C++ Library that they normally use do not +follow the same ABI for the Standard C++ Library, object files built with +those compilers can be used in the same program only if they use the same +C++ library. This requires specifying the location of the C++ library +header files when invoking the compiler whose usual library is not being +used. The location of GCC's C++ header files depends on how the GCC +build was configured, but can be seen by using the G++ @option{-v} option. +With default configuration options for G++ 3.3 the compile line for a +different C++ compiler needs to include + +@smallexample + -I@var{gcc_install_directory}/include/c++/3.3 +@end smallexample + +Similarly, compiling code with G++ that must use a C++ library other +than the GNU C++ library requires specifying the location of the header +files for that other library. + +The most straightforward way to link a program to use a particular +C++ library is to use a C++ driver that specifies that C++ library by +default. The @command{g++} driver, for example, tells the linker where +to find GCC's C++ library (@file{libstdc++}) plus the other libraries +and startup files it needs, in the proper order. + +If a program must use a different C++ library and it's not possible +to do the final link using a C++ driver that uses that library by default, +it is necessary to tell @command{g++} the location and name of that +library. It might also be necessary to specify different startup files +and other runtime support libraries, and to suppress the use of GCC's +support libraries with one or more of the options @option{-nostdlib}, +@option{-nostartfiles}, and @option{-nodefaultlibs}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/configfiles.texi b/gcc-4.2.1-5666.3/gcc/doc/configfiles.texi new file mode 100644 index 000000000..f24b85d71 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/configfiles.texi @@ -0,0 +1,74 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Configuration Files +@subsubsection Files Created by @code{configure} + +Here we spell out what files will be set up by @file{configure} in the +@file{gcc} directory. Some other files are created as temporary files +in the configuration process, and are not used in the subsequent +build; these are not documented. + +@itemize @bullet +@item +@file{Makefile} is constructed from @file{Makefile.in}, together with +the host and target fragments (@pxref{Fragments, , Makefile +Fragments}) @file{t-@var{target}} and @file{x-@var{host}} from +@file{config}, if any, and language Makefile fragments +@file{@var{language}/Make-lang.in}. +@item +@file{auto-host.h} contains information about the host machine +determined by @file{configure}. If the host machine is different from +the build machine, then @file{auto-build.h} is also created, +containing such information about the build machine. +@item +@file{config.status} is a script that may be run to recreate the +current configuration. +@item +@file{configargs.h} is a header containing details of the arguments +passed to @file{configure} to configure GCC, and of the thread model +used. +@item +@file{cstamp-h} is used as a timestamp. +@item +@file{fixinc/Makefile} is constructed from @file{fixinc/Makefile.in}. +@item +@file{gccbug}, a script for reporting bugs in GCC, is constructed from +@file{gccbug.in}. +@item +@file{intl/Makefile} is constructed from @file{intl/Makefile.in}. +@item +@file{mklibgcc}, a shell script to create a Makefile to build libgcc, +is constructed from @file{mklibgcc.in}. +@item +If a language @file{config-lang.in} file (@pxref{Front End Config, , +The Front End @file{config-lang.in} File}) sets @code{outputs}, then +the files listed in @code{outputs} there are also generated. +@end itemize + +The following configuration headers are created from the Makefile, +using @file{mkconfig.sh}, rather than directly by @file{configure}. +@file{config.h}, @file{bconfig.h} and @file{tconfig.h} all contain the +@file{xm-@var{machine}.h} header, if any, appropriate to the host, +build and target machines respectively, the configuration headers for +the target, and some definitions; for the host and build machines, +these include the autoconfigured headers generated by +@file{configure}. The other configuration headers are determined by +@file{config.gcc}. They also contain the typedefs for @code{rtx}, +@code{rtvec} and @code{tree}. + +@itemize @bullet +@item +@file{config.h}, for use in programs that run on the host machine. +@item +@file{bconfig.h}, for use in programs that run on the build machine. +@item +@file{tconfig.h}, for use in programs and libraries for the target +machine. +@item +@file{tm_p.h}, which includes the header @file{@var{machine}-protos.h} +that contains prototypes for functions in the target @file{.c} file. +FIXME: why is such a separate header necessary? +@end itemize diff --git a/gcc-4.2.1-5666.3/gcc/doc/configterms.texi b/gcc-4.2.1-5666.3/gcc/doc/configterms.texi new file mode 100644 index 000000000..f97de5bd0 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/configterms.texi @@ -0,0 +1,61 @@ +@c Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Configure Terms +@section Configure Terms and History +@cindex configure terms +@cindex canadian + +The configure and build process has a long and colorful history, and can +be confusing to anyone who doesn't know why things are the way they are. +While there are other documents which describe the configuration process +in detail, here are a few things that everyone working on GCC should +know. + +There are three system names that the build knows about: the machine you +are building on (@dfn{build}), the machine that you are building for +(@dfn{host}), and the machine that GCC will produce code for +(@dfn{target}). When you configure GCC, you specify these with +@option{--build=}, @option{--host=}, and @option{--target=}. + +Specifying the host without specifying the build should be avoided, as +@command{configure} may (and once did) assume that the host you specify +is also the build, which may not be true. + +If build, host, and target are all the same, this is called a +@dfn{native}. If build and host are the same but target is different, +this is called a @dfn{cross}. If build, host, and target are all +different this is called a @dfn{canadian} (for obscure reasons dealing +with Canada's political party and the background of the person working +on the build at that time). If host and target are the same, but build +is different, you are using a cross-compiler to build a native for a +different system. Some people call this a @dfn{host-x-host}, +@dfn{crossed native}, or @dfn{cross-built native}. If build and target +are the same, but host is different, you are using a cross compiler to +build a cross compiler that produces code for the machine you're +building on. This is rare, so there is no common way of describing it. +There is a proposal to call this a @dfn{crossback}. + +If build and host are the same, the GCC you are building will also be +used to build the target libraries (like @code{libstdc++}). If build and host +are different, you must have already build and installed a cross +compiler that will be used to build the target libraries (if you +configured with @option{--target=foo-bar}, this compiler will be called +@command{foo-bar-gcc}). + +In the case of target libraries, the machine you're building for is the +machine you specified with @option{--target}. So, build is the machine +you're building on (no change there), host is the machine you're +building for (the target libraries are built for the target, so host is +the target you specified), and target doesn't apply (because you're not +building a compiler, you're building libraries). The configure/make +process will adjust these variables as needed. It also sets +@code{$with_cross_host} to the original @option{--host} value in case you +need it. + +The @code{libiberty} support library is built up to three times: once +for the host, once for the target (even if they are the same), and once +for the build if build and host are different. This allows it to be +used by all programs which are generated in the course of the build +process. diff --git a/gcc-4.2.1-5666.3/gcc/doc/contrib.texi b/gcc-4.2.1-5666.3/gcc/doc/contrib.texi new file mode 100644 index 000000000..16c8af58d --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/contrib.texi @@ -0,0 +1,1597 @@ +@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000, +@c 2001,2002,2003,2004,2005,2006,2007 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Contributors +@unnumbered Contributors to GCC +@cindex contributors + +The GCC project would like to thank its many contributors. Without them the +project would not have been nearly as successful as it has been. Any omissions +in this list are accidental. Feel free to contact +@email{law@@redhat.com} or @email{gerald@@pfeifer.com} if you have been left +out or some of your contributions are not listed. Please keep this list in +alphabetical order. + +@itemize @bullet + +@item +Analog Devices helped implement the support for complex data types +and iterators. + +@item +John David Anglin for threading-related fixes and improvements to +libstdc++-v3, and the HP-UX port. + +@item +James van Artsdalen wrote the code that makes efficient use of +the Intel 80387 register stack. + +@item +Abramo and Roberto Bagnara for the SysV68 Motorola 3300 Delta Series +port. + +@item +Alasdair Baird for various bug fixes. + +@item +Giovanni Bajo for analyzing lots of complicated C++ problem reports. + +@item +Peter Barada for his work to improve code generation for new +ColdFire cores. + +@item +Gerald Baumgartner added the signature extension to the C++ front end. + +@item +Godmar Back for his Java improvements and encouragement. + +@item +Scott Bambrough for help porting the Java compiler. + +@item +Wolfgang Bangerth for processing tons of bug reports. + +@item +Jon Beniston for his Microsoft Windows port of Java. + +@item +Daniel Berlin for better DWARF2 support, faster/better optimizations, +improved alias analysis, plus migrating GCC to Bugzilla. + +@item +Geoff Berry for his Java object serialization work and various patches. + +@item +Uros Bizjak for the implementation of x87 math built-in functions and +for various middle end and i386 back end improvements and bugfixes. + +@item +Eric Blake for helping to make GCJ and libgcj conform to the +specifications. + +@item +Janne Blomqvist for contributions to GNU Fortran. + +@item +Segher Boessenkool for various fixes. + +@item +Hans-J. Boehm for his @uref{http://www.hpl.hp.com/personal/Hans_Boehm/gc/,, +garbage collector}, IA-64 libffi port, and other Java work. + +@item +Neil Booth for work on cpplib, lang hooks, debug hooks and other +miscellaneous clean-ups. + +@item +Steven Bosscher for integrating the GNU Fortran front end into GCC and for +contributing to the tree-ssa branch. + +@item +Eric Botcazou for fixing middle- and backend bugs left and right. + +@item +Per Bothner for his direction via the steering committee and various +improvements to the infrastructure for supporting new languages. Chill +front end implementation. Initial implementations of +cpplib, fix-header, config.guess, libio, and past C++ library (libg++) +maintainer. Dreaming up, designing and implementing much of GCJ@. + +@item +Devon Bowen helped port GCC to the Tahoe. + +@item +Don Bowman for mips-vxworks contributions. + +@item +Dave Brolley for work on cpplib and Chill. + +@item +Paul Brook for work on the ARM architecture and maintaining GNU Fortran. + +@item +Robert Brown implemented the support for Encore 32000 systems. + +@item +Christian Bruel for improvements to local store elimination. + +@item +Herman A.J. ten Brugge for various fixes. + +@item +Joerg Brunsmann for Java compiler hacking and help with the GCJ FAQ@. + +@item +Joe Buck for his direction via the steering committee. + +@item +Craig Burley for leadership of the G77 Fortran effort. + +@item +Stephan Buys for contributing Doxygen notes for libstdc++. + +@item +Paolo Carlini for libstdc++ work: lots of efficiency improvements to +the C++ strings, streambufs and formatted I/O, hard detective work on +the frustrating localization issues, and keeping up with the problem reports. + +@item +John Carr for his alias work, SPARC hacking, infrastructure improvements, +previous contributions to the steering committee, loop optimizations, etc. + +@item +Stephane Carrez for 68HC11 and 68HC12 ports. + +@item +Steve Chamberlain for support for the Renesas SH and H8 processors +and the PicoJava processor, and for GCJ config fixes. + +@item +Glenn Chambers for help with the GCJ FAQ@. + +@item +John-Marc Chandonia for various libgcj patches. + +@item +Scott Christley for his Objective-C contributions. + +@item +Eric Christopher for his Java porting help and clean-ups. + +@item +Branko Cibej for more warning contributions. + +@item +The @uref{http://www.gnu.org/software/classpath/,,GNU Classpath project} +for all of their merged runtime code. + +@item +Nick Clifton for arm, mcore, fr30, v850, m32r work, @option{--help}, and +other random hacking. + +@item +Michael Cook for libstdc++ cleanup patches to reduce warnings. + +@item +R. Kelley Cook for making GCC buildable from a read-only directory as +well as other miscellaneous build process and documentation clean-ups. + +@item +Ralf Corsepius for SH testing and minor bugfixing. + +@item +Stan Cox for care and feeding of the x86 port and lots of behind +the scenes hacking. + +@item +Alex Crain provided changes for the 3b1. + +@item +Ian Dall for major improvements to the NS32k port. + +@item +Paul Dale for his work to add uClinux platform support to the +m68k backend. + +@item +Dario Dariol contributed the four varieties of sample programs +that print a copy of their source. + +@item +Russell Davidson for fstream and stringstream fixes in libstdc++. + +@item +Bud Davis for work on the G77 and GNU Fortran compilers. + +@item +Mo DeJong for GCJ and libgcj bug fixes. + +@item +DJ Delorie for the DJGPP port, build and libiberty maintenance, +various bug fixes, and the M32C port. + +@item +Arnaud Desitter for helping to debug GNU Fortran. + +@item +Gabriel Dos Reis for contributions to G++, contributions and +maintenance of GCC diagnostics infrastructure, libstdc++-v3, +including @code{valarray<>}, @code{complex<>}, maintaining the numerics library +(including that pesky @code{<limits>} :-) and keeping up-to-date anything +to do with numbers. + +@item +Ulrich Drepper for his work on glibc, testing of GCC using glibc, ISO C99 +support, CFG dumping support, etc., plus support of the C++ runtime +libraries including for all kinds of C interface issues, contributing and +maintaining @code{complex<>}, sanity checking and disbursement, configuration +architecture, libio maintenance, and early math work. + +@item +Zdenek Dvorak for a new loop unroller and various fixes. + +@item +Richard Earnshaw for his ongoing work with the ARM@. + +@item +David Edelsohn for his direction via the steering committee, ongoing work +with the RS6000/PowerPC port, help cleaning up Haifa loop changes, +doing the entire AIX port of libstdc++ with his bare hands, and for +ensuring GCC properly keeps working on AIX@. + +@item +Kevin Ediger for the floating point formatting of num_put::do_put in +libstdc++. + +@item +Phil Edwards for libstdc++ work including configuration hackery, +documentation maintainer, chief breaker of the web pages, the occasional +iostream bug fix, and work on shared library symbol versioning. + +@item +Paul Eggert for random hacking all over GCC@. + +@item +Mark Elbrecht for various DJGPP improvements, and for libstdc++ +configuration support for locales and fstream-related fixes. + +@item +Vadim Egorov for libstdc++ fixes in strings, streambufs, and iostreams. + +@item +Christian Ehrhardt for dealing with bug reports. + +@item +Ben Elliston for his work to move the Objective-C runtime into its +own subdirectory and for his work on autoconf. + +@item +Marc Espie for OpenBSD support. + +@item +Doug Evans for much of the global optimization framework, arc, m32r, +and SPARC work. + +@item +Christopher Faylor for his work on the Cygwin port and for caring and +feeding the gcc.gnu.org box and saving its users tons of spam. + +@item +Fred Fish for BeOS support and Ada fixes. + +@item +Ivan Fontes Garcia for the Portuguese translation of the GCJ FAQ@. + +@item +Peter Gerwinski for various bug fixes and the Pascal front end. + +@item +Kaveh R.@: Ghazi for his direction via the steering committee, amazing +work to make @samp{-W -Wall -W* -Werror} useful, and continuously +testing GCC on a plethora of platforms. Kaveh extends his gratitude to +the @uref{http://www.caip.rutgers.edu,,CAIP Center} at Rutgers +University for providing him with computing resources to work on Free +Software since the late 1980s. + +@item +John Gilmore for a donation to the FSF earmarked improving GNU Java. + +@item +Judy Goldberg for c++ contributions. + +@item +Torbjorn Granlund for various fixes and the c-torture testsuite, +multiply- and divide-by-constant optimization, improved long long +support, improved leaf function register allocation, and his direction +via the steering committee. + +@item +Anthony Green for his @option{-Os} contributions and Java front end work. + +@item +Stu Grossman for gdb hacking, allowing GCJ developers to debug Java code. + +@item +Michael K. Gschwind contributed the port to the PDP-11. + +@item +Ron Guilmette implemented the @command{protoize} and @command{unprotoize} +tools, the support for Dwarf symbolic debugging information, and much of +the support for System V Release 4. He has also worked heavily on the +Intel 386 and 860 support. + +@item +Mostafa Hagog for Swing Modulo Scheduling (SMS) and post reload GCSE@. + +@item +Bruno Haible for improvements in the runtime overhead for EH, new +warnings and assorted bug fixes. + +@item +Andrew Haley for his amazing Java compiler and library efforts. + +@item +Chris Hanson assisted in making GCC work on HP-UX for the 9000 series 300. + +@item +Michael Hayes for various thankless work he's done trying to get +the c30/c40 ports functional. Lots of loop and unroll improvements and +fixes. + +@item +Dara Hazeghi for wading through myriads of target-specific bug reports. + +@item +Kate Hedstrom for staking the G77 folks with an initial testsuite. + +@item +Richard Henderson for his ongoing SPARC, alpha, ia32, and ia64 work, loop +opts, and generally fixing lots of old problems we've ignored for +years, flow rewrite and lots of further stuff, including reviewing +tons of patches. + +@item +Aldy Hernandez for working on the PowerPC port, SIMD support, and +various fixes. + +@item +Nobuyuki Hikichi of Software Research Associates, Tokyo, contributed +the support for the Sony NEWS machine. + +@item +Kazu Hirata for caring and feeding the Renesas H8/300 port and various fixes. + +@item +Katherine Holcomb for work on GNU Fortran. + +@item +Manfred Hollstein for his ongoing work to keep the m88k alive, lots +of testing and bug fixing, particularly of GCC configury code. + +@item +Steve Holmgren for MachTen patches. + +@item +Jan Hubicka for his x86 port improvements. + +@item +Falk Hueffner for working on C and optimization bug reports. + +@item +Bernardo Innocenti for his m68k work, including merging of +ColdFire improvements and uClinux support. + +@item +Christian Iseli for various bug fixes. + +@item +Kamil Iskra for general m68k hacking. + +@item +Lee Iverson for random fixes and MIPS testing. + +@item +Andreas Jaeger for testing and benchmarking of GCC and various bug fixes. + +@item +Jakub Jelinek for his SPARC work and sibling call optimizations as well +as lots of bug fixes and test cases, and for improving the Java build +system. + +@item +Janis Johnson for ia64 testing and fixes, her quality improvement +sidetracks, and web page maintenance. + +@item +Kean Johnston for SCO OpenServer support and various fixes. + +@item +Tim Josling for the sample language treelang based originally on Richard +Kenner's ``toy'' language. + +@item +Nicolai Josuttis for additional libstdc++ documentation. + +@item +Klaus Kaempf for his ongoing work to make alpha-vms a viable target. + +@item +Steven G. Kargl for work on GNU Fortran. + +@item +David Kashtan of SRI adapted GCC to VMS@. + +@item +Ryszard Kabatek for many, many libstdc++ bug fixes and optimizations of +strings, especially member functions, and for auto_ptr fixes. + +@item +Geoffrey Keating for his ongoing work to make the PPC work for GNU/Linux +and his automatic regression tester. + +@item +Brendan Kehoe for his ongoing work with G++ and for a lot of early work +in just about every part of libstdc++. + +@item +Oliver M. Kellogg of Deutsche Aerospace contributed the port to the +MIL-STD-1750A@. + +@item +Richard Kenner of the New York University Ultracomputer Research +Laboratory wrote the machine descriptions for the AMD 29000, the DEC +Alpha, the IBM RT PC, and the IBM RS/6000 as well as the support for +instruction attributes. He also made changes to better support RISC +processors including changes to common subexpression elimination, +strength reduction, function calling sequence handling, and condition +code support, in addition to generalizing the code for frame pointer +elimination and delay slot scheduling. Richard Kenner was also the +head maintainer of GCC for several years. + +@item +Mumit Khan for various contributions to the Cygwin and Mingw32 ports and +maintaining binary releases for Microsoft Windows hosts, and for massive libstdc++ +porting work to Cygwin/Mingw32. + +@item +Robin Kirkham for cpu32 support. + +@item +Mark Klein for PA improvements. + +@item +Thomas Koenig for various bug fixes. + +@item +Bruce Korb for the new and improved fixincludes code. + +@item +Benjamin Kosnik for his G++ work and for leading the libstdc++-v3 effort. + +@item +Charles LaBrec contributed the support for the Integrated Solutions +68020 system. + +@item +Asher Langton and Mike Kumbera for contributing Cray pointer support +to GNU Fortran, and for other GNU Fortran improvements. + +@item +Jeff Law for his direction via the steering committee, coordinating the +entire egcs project and GCC 2.95, rolling out snapshots and releases, +handling merges from GCC2, reviewing tons of patches that might have +fallen through the cracks else, and random but extensive hacking. + +@item +Marc Lehmann for his direction via the steering committee and helping +with analysis and improvements of x86 performance. + +@item +Victor Leikehman for work on GNU Fortran. + +@item +Ted Lemon wrote parts of the RTL reader and printer. + +@item +Kriang Lerdsuwanakij for C++ improvements including template as template +parameter support, and many C++ fixes. + +@item +Warren Levy for tremendous work on libgcj (Java Runtime Library) and +random work on the Java front end. + +@item +Alain Lichnewsky ported GCC to the MIPS CPU@. + +@item +Oskar Liljeblad for hacking on AWT and his many Java bug reports and +patches. + +@item +Robert Lipe for OpenServer support, new testsuites, testing, etc. + +@item +Weiwen Liu for testing and various bug fixes. + +@item +Dave Love for his ongoing work with the Fortran front end and +runtime libraries. + +@item +Martin von L@"owis for internal consistency checking infrastructure, +various C++ improvements including namespace support, and tons of +assistance with libstdc++/compiler merges. + +@item +H.J. Lu for his previous contributions to the steering committee, many x86 +bug reports, prototype patches, and keeping the GNU/Linux ports working. + +@item +Greg McGary for random fixes and (someday) bounded pointers. + +@item +Andrew MacLeod for his ongoing work in building a real EH system, +various code generation improvements, work on the global optimizer, etc. + +@item +Vladimir Makarov for hacking some ugly i960 problems, PowerPC hacking +improvements to compile-time performance, overall knowledge and +direction in the area of instruction scheduling, and design and +implementation of the automaton based instruction scheduler. + +@item +Bob Manson for his behind the scenes work on dejagnu. + +@item +Philip Martin for lots of libstdc++ string and vector iterator fixes and +improvements, and string clean up and testsuites. + +@item +All of the Mauve project +@uref{http://sourceware.org/cgi-bin/cvsweb.cgi/~checkout~/mauve/THANKS?rev=1.2&cvsroot=mauve&only_with_tag=HEAD,,contributors}, +for Java test code. + +@item +Bryce McKinlay for numerous GCJ and libgcj fixes and improvements. + +@item +Adam Megacz for his work on the Microsoft Windows port of GCJ@. + +@item +Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS, +powerpc, haifa, ECOFF debug support, and other assorted hacking. + +@item +Jason Merrill for his direction via the steering committee and leading +the G++ effort. + +@item +Martin Michlmayr for testing GCC on several architectures using the +entire Debian archive. + +@item +David Miller for his direction via the steering committee, lots of +SPARC work, improvements in jump.c and interfacing with the Linux kernel +developers. + +@item +Gary Miller ported GCC to Charles River Data Systems machines. + +@item +Alfred Minarik for libstdc++ string and ios bug fixes, and turning the +entire libstdc++ testsuite namespace-compatible. + +@item +Mark Mitchell for his direction via the steering committee, mountains of +C++ work, load/store hoisting out of loops, alias analysis improvements, +ISO C @code{restrict} support, and serving as release manager for GCC 3.x. + +@item +Alan Modra for various GNU/Linux bits and testing. + +@item +Toon Moene for his direction via the steering committee, Fortran +maintenance, and his ongoing work to make us make Fortran run fast. + +@item +Jason Molenda for major help in the care and feeding of all the services +on the gcc.gnu.org (formerly egcs.cygnus.com) machine---mail, web +services, ftp services, etc etc. Doing all this work on scrap paper and +the backs of envelopes would have been@dots{} difficult. + +@item +Catherine Moore for fixing various ugly problems we have sent her +way, including the haifa bug which was killing the Alpha & PowerPC +Linux kernels. + +@item +Mike Moreton for his various Java patches. + +@item +David Mosberger-Tang for various Alpha improvements, and for the initial +IA-64 port. + +@item +Stephen Moshier contributed the floating point emulator that assists in +cross-compilation and permits support for floating point numbers wider +than 64 bits and for ISO C99 support. + +@item +Bill Moyer for his behind the scenes work on various issues. + +@item +Philippe De Muyter for his work on the m68k port. + +@item +Joseph S. Myers for his work on the PDP-11 port, format checking and ISO +C99 support, and continuous emphasis on (and contributions to) documentation. + +@item +Nathan Myers for his work on libstdc++-v3: architecture and authorship +through the first three snapshots, including implementation of locale +infrastructure, string, shadow C headers, and the initial project +documentation (DESIGN, CHECKLIST, and so forth). Later, more work on +MT-safe string and shadow headers. + +@item +Felix Natter for documentation on porting libstdc++. + +@item +Nathanael Nerode for cleaning up the configuration/build process. + +@item +NeXT, Inc.@: donated the front end that supports the Objective-C +language. + +@item +Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to the search +engine setup, various documentation fixes and other small fixes. + +@item +Geoff Noer for his work on getting cygwin native builds working. + +@item +Diego Novillo for his work on Tree SSA, OpenMP, SPEC performance +tracking web pages and assorted fixes. + +@item +David O'Brien for the FreeBSD/alpha, FreeBSD/AMD x86-64, FreeBSD/ARM, +FreeBSD/PowerPC, and FreeBSD/SPARC64 ports and related infrastructure +improvements. + +@item +Alexandre Oliva for various build infrastructure improvements, scripts and +amazing testing work, including keeping libtool issues sane and happy. + +@item +Stefan Olsson for work on mt_alloc. + +@item +Melissa O'Neill for various NeXT fixes. + +@item +Rainer Orth for random MIPS work, including improvements to GCC's o32 +ABI support, improvements to dejagnu's MIPS support, Java configuration +clean-ups and porting work, etc. + +@item +Hartmut Penner for work on the s390 port. + +@item +Paul Petersen wrote the machine description for the Alliant FX/8. + +@item +Alexandre Petit-Bianco for implementing much of the Java compiler and +continued Java maintainership. + +@item +Matthias Pfaller for major improvements to the NS32k port. + +@item +Gerald Pfeifer for his direction via the steering committee, pointing +out lots of problems we need to solve, maintenance of the web pages, and +taking care of documentation maintenance in general. + +@item +Andrew Pinski for processing bug reports by the dozen. + +@item +Ovidiu Predescu for his work on the Objective-C front end and runtime +libraries. + +@item +Jerry Quinn for major performance improvements in C++ formatted I/O@. + +@item +Ken Raeburn for various improvements to checker, MIPS ports and various +cleanups in the compiler. + +@item +Rolf W. Rasmussen for hacking on AWT@. + +@item +David Reese of Sun Microsystems contributed to the Solaris on PowerPC +port. + +@item +Volker Reichelt for keeping up with the problem reports. + +@item +Joern Rennecke for maintaining the sh port, loop, regmove & reload +hacking. + +@item +Loren J. Rittle for improvements to libstdc++-v3 including the FreeBSD +port, threading fixes, thread-related configury changes, critical +threading documentation, and solutions to really tricky I/O problems, +as well as keeping GCC properly working on FreeBSD and continuous testing. + +@item +Craig Rodrigues for processing tons of bug reports. + +@item +Ola R@"onnerup for work on mt_alloc. + +@item +Gavin Romig-Koch for lots of behind the scenes MIPS work. + +@item +David Ronis inspired and encouraged Craig to rewrite the G77 +documentation in texinfo format by contributing a first pass at a +translation of the old @file{g77-0.5.16/f/DOC} file. + +@item +Ken Rose for fixes to GCC's delay slot filling code. + +@item +Paul Rubin wrote most of the preprocessor. + +@item +P@'etur Run@'olfsson for major performance improvements in C++ formatted I/O and +large file support in C++ filebuf. + +@item +Chip Salzenberg for libstdc++ patches and improvements to locales, traits, +Makefiles, libio, libtool hackery, and ``long long'' support. + +@item +Juha Sarlin for improvements to the H8 code generator. + +@item +Greg Satz assisted in making GCC work on HP-UX for the 9000 series 300. + +@item +Roger Sayle for improvements to constant folding and GCC's RTL optimizers +as well as for fixing numerous bugs. + +@item +Bradley Schatz for his work on the GCJ FAQ@. + +@item +Peter Schauer wrote the code to allow debugging to work on the Alpha. + +@item +William Schelter did most of the work on the Intel 80386 support. + +@item +Tobias Schl@"uter for work on GNU Fortran. + +@item +Bernd Schmidt for various code generation improvements and major +work in the reload pass as well a serving as release manager for +GCC 2.95.3. + +@item +Peter Schmid for constant testing of libstdc++---especially application +testing, going above and beyond what was requested for the release +criteria---and libstdc++ header file tweaks. + +@item +Jason Schroeder for jcf-dump patches. + +@item +Andreas Schwab for his work on the m68k port. + +@item +Lars Segerlund for work on GNU Fortran. + +@item +Joel Sherrill for his direction via the steering committee, RTEMS +contributions and RTEMS testing. + +@item +Nathan Sidwell for many C++ fixes/improvements. + +@item +Jeffrey Siegal for helping RMS with the original design of GCC, some +code which handles the parse tree and RTL data structures, constant +folding and help with the original VAX & m68k ports. + +@item +Kenny Simpson for prompting libstdc++ fixes due to defect reports from +the LWG (thereby keeping GCC in line with updates from the ISO)@. + +@item +Franz Sirl for his ongoing work with making the PPC port stable +for GNU/Linux. + +@item +Andrey Slepuhin for assorted AIX hacking. + +@item +Christopher Smith did the port for Convex machines. + +@item +Danny Smith for his major efforts on the Mingw (and Cygwin) ports. + +@item +Randy Smith finished the Sun FPA support. + +@item +Scott Snyder for queue, iterator, istream, and string fixes and libstdc++ +testsuite entries. Also for providing the patch to G77 to add +rudimentary support for @code{INTEGER*1}, @code{INTEGER*2}, and +@code{LOGICAL*1}. + +@item +Brad Spencer for contributions to the GLIBCPP_FORCE_NEW technique. + +@item +Richard Stallman, for writing the original GCC and launching the GNU project. + +@item +Jan Stein of the Chalmers Computer Society provided support for +Genix, as well as part of the 32000 machine description. + +@item +Nigel Stephens for various mips16 related fixes/improvements. + +@item +Jonathan Stone wrote the machine description for the Pyramid computer. + +@item +Graham Stott for various infrastructure improvements. + +@item +John Stracke for his Java HTTP protocol fixes. + +@item +Mike Stump for his Elxsi port, G++ contributions over the years and more +recently his vxworks contributions + +@item +Jeff Sturm for Java porting help, bug fixes, and encouragement. + +@item +Shigeya Suzuki for this fixes for the bsdi platforms. + +@item +Ian Lance Taylor for his mips16 work, general configury hacking, +fixincludes, etc. + +@item +Holger Teutsch provided the support for the Clipper CPU@. + +@item +Gary Thomas for his ongoing work to make the PPC work for GNU/Linux. + +@item +Philipp Thomas for random bug fixes throughout the compiler + +@item +Jason Thorpe for thread support in libstdc++ on NetBSD@. + +@item +Kresten Krab Thorup wrote the run time support for the Objective-C +language and the fantastic Java bytecode interpreter. + +@item +Michael Tiemann for random bug fixes, the first instruction scheduler, +initial C++ support, function integration, NS32k, SPARC and M88k +machine description work, delay slot scheduling. + +@item +Andreas Tobler for his work porting libgcj to Darwin. + +@item +Teemu Torma for thread safe exception handling support. + +@item +Leonard Tower wrote parts of the parser, RTL generator, and RTL +definitions, and of the VAX machine description. + +@item +Tom Tromey for internationalization support and for his many Java +contributions and libgcj maintainership. + +@item +Lassi Tuura for improvements to config.guess to determine HP processor +types. + +@item +Petter Urkedal for libstdc++ CXXFLAGS, math, and algorithms fixes. + +@item +Andy Vaught for the design and initial implementation of the GNU Fortran +front end. + +@item +Brent Verner for work with the libstdc++ cshadow files and their +associated configure steps. + +@item +Todd Vierling for contributions for NetBSD ports. + +@item +Jonathan Wakely for contributing libstdc++ Doxygen notes and XHTML +guidance. + +@item +Dean Wakerley for converting the install documentation from HTML to texinfo +in time for GCC 3.0. + +@item +Krister Walfridsson for random bug fixes. + +@item +Feng Wang for contributions to GNU Fortran. + +@item +Stephen M. Webb for time and effort on making libstdc++ shadow files +work with the tricky Solaris 8+ headers, and for pushing the build-time +header tree. + +@item +John Wehle for various improvements for the x86 code generator, +related infrastructure improvements to help x86 code generation, +value range propagation and other work, WE32k port. + +@item +Ulrich Weigand for work on the s390 port. + +@item +Zack Weinberg for major work on cpplib and various other bug fixes. + +@item +Matt Welsh for help with Linux Threads support in GCJ@. + +@item +Urban Widmark for help fixing java.io. + +@item +Mark Wielaard for new Java library code and his work integrating with +Classpath. + +@item +Dale Wiles helped port GCC to the Tahoe. + +@item +Bob Wilson from Tensilica, Inc.@: for the Xtensa port. + +@item +Jim Wilson for his direction via the steering committee, tackling hard +problems in various places that nobody else wanted to work on, strength +reduction and other loop optimizations. + +@item +Paul Woegerer and Tal Agmon for the CRX port. + +@item +Carlo Wood for various fixes. + +@item +Tom Wood for work on the m88k port. + +@item +Canqun Yang for work on GNU Fortran. + +@item +Masanobu Yuhara of Fujitsu Laboratories implemented the machine +description for the Tron architecture (specifically, the Gmicro). + +@item +Kevin Zachmann helped port GCC to the Tahoe. + +@item +Ayal Zaks for Swing Modulo Scheduling (SMS). + +@item +Xiaoqiang Zhang for work on GNU Fortran. + +@item +Gilles Zunino for help porting Java to Irix. + +@end itemize + +The following people are recognized for their contributions to GNAT, +the Ada front end of GCC: +@itemize @bullet +@item +Bernard Banner + +@item +Romain Berrendonner + +@item +Geert Bosch + +@item +Emmanuel Briot + +@item +Joel Brobecker + +@item +Ben Brosgol + +@item +Vincent Celier + +@item +Arnaud Charlet + +@item +Chien Chieng + +@item +Cyrille Comar + +@item +Cyrille Crozes + +@item +Robert Dewar + +@item +Gary Dismukes + +@item +Robert Duff + +@item +Ed Falis + +@item +Ramon Fernandez + +@item +Sam Figueroa + +@item +Vasiliy Fofanov + +@item +Michael Friess + +@item +Franco Gasperoni + +@item +Ted Giering + +@item +Matthew Gingell + +@item +Laurent Guerby + +@item +Jerome Guitton + +@item +Olivier Hainque + +@item +Jerome Hugues + +@item +Hristian Kirtchev + +@item +Jerome Lambourg + +@item +Bruno Leclerc + +@item +Albert Lee + +@item +Sean McNeil + +@item +Javier Miranda + +@item +Laurent Nana + +@item +Pascal Obry + +@item +Dong-Ik Oh + +@item +Laurent Pautet + +@item +Brett Porter + +@item +Thomas Quinot + +@item +Nicolas Roche + +@item +Pat Rogers + +@item +Jose Ruiz + +@item +Douglas Rupp + +@item +Sergey Rybin + +@item +Gail Schenker + +@item +Ed Schonberg + +@item +Nicolas Setton + +@item +Samuel Tardieu + +@end itemize + + +The following people are recognized for their contributions of new +features, bug reports, testing and integration of classpath/libgcj for +GCC version 4.1: +@itemize @bullet +@item +Lillian Angel for @code{JTree} implementation and lots Free Swing +additions and bugfixes. + +@item +Wolfgang Baer for @code{GapContent} bugfixes. + +@item +Anthony Balkissoon for @code{JList}, Free Swing 1.5 updates and mouse event +fixes, lots of Free Swing work including @code{JTable} editing. + +@item +Stuart Ballard for RMI constant fixes. + +@item +Goffredo Baroncelli for @code{HTTPURLConnection} fixes. + +@item +Gary Benson for @code{MessageFormat} fixes. + +@item +Daniel Bonniot for @code{Serialization} fixes. + +@item +Chris Burdess for lots of gnu.xml and http protocol fixes, @code{StAX} +and @code{DOM xml:id} support. + +@item +Ka-Hing Cheung for @code{TreePath} and @code{TreeSelection} fixes. + +@item +Archie Cobbs for build fixes, VM interface updates, +@code{URLClassLoader} updates. + +@item +Kelley Cook for build fixes. + +@item +Martin Cordova for Suggestions for better @code{SocketTimeoutException}. + +@item +David Daney for @code{BitSet} bugfixes, @code{HttpURLConnection} +rewrite and improvements. + +@item +Thomas Fitzsimmons for lots of upgrades to the gtk+ AWT and Cairo 2D +support. Lots of imageio framework additions, lots of AWT and Free +Swing bugfixes. + +@item +Jeroen Frijters for @code{ClassLoader} and nio cleanups, serialization fixes, +better @code{Proxy} support, bugfixes and IKVM integration. + +@item +Santiago Gala for @code{AccessControlContext} fixes. + +@item +Nicolas Geoffray for @code{VMClassLoader} and @code{AccessController} +improvements. + +@item +David Gilbert for @code{basic} and @code{metal} icon and plaf support +and lots of documenting, Lots of Free Swing and metal theme +additions. @code{MetalIconFactory} implementation. + +@item +Anthony Green for @code{MIDI} framework, @code{ALSA} and @code{DSSI} +providers. + +@item +Andrew Haley for @code{Serialization} and @code{URLClassLoader} fixes, +gcj build speedups. + +@item +Kim Ho for @code{JFileChooser} implementation. + +@item +Andrew John Hughes for @code{Locale} and net fixes, URI RFC2986 +updates, @code{Serialization} fixes, @code{Properties} XML support and +generic branch work, VMIntegration guide update. + +@item +Bastiaan Huisman for @code{TimeZone} bugfixing. + +@item +Andreas Jaeger for mprec updates. + +@item +Paul Jenner for better @option{-Werror} support. + +@item +Ito Kazumitsu for @code{NetworkInterface} implementation and updates. + +@item +Roman Kennke for @code{BoxLayout}, @code{GrayFilter} and +@code{SplitPane}, plus bugfixes all over. Lots of Free Swing work +including styled text. + +@item +Simon Kitching for @code{String} cleanups and optimization suggestions. + +@item +Michael Koch for configuration fixes, @code{Locale} updates, bug and +build fixes. + +@item +Guilhem Lavaux for configuration, thread and channel fixes and Kaffe +integration. JCL native @code{Pointer} updates. Logger bugfixes. + +@item +David Lichteblau for JCL support library global/local reference +cleanups. + +@item +Aaron Luchko for JDWP updates and documentation fixes. + +@item +Ziga Mahkovec for @code{Graphics2D} upgraded to Cairo 0.5 and new regex +features. + +@item +Sven de Marothy for BMP imageio support, CSS and @code{TextLayout} +fixes. @code{GtkImage} rewrite, 2D, awt, free swing and date/time fixes and +implementing the Qt4 peers. + +@item +Casey Marshall for crypto algorithm fixes, @code{FileChannel} lock, +@code{SystemLogger} and @code{FileHandler} rotate implementations, NIO +@code{FileChannel.map} support, security and policy updates. + +@item +Bryce McKinlay for RMI work. + +@item +Audrius Meskauskas for lots of Free Corba, RMI and HTML work plus +testing and documenting. + +@item +Kalle Olavi Niemitalo for build fixes. + +@item +Rainer Orth for build fixes. + +@item +Andrew Overholt for @code{File} locking fixes. + +@item +Ingo Proetel for @code{Image}, @code{Logger} and @code{URLClassLoader} +updates. + +@item +Olga Rodimina for @code{MenuSelectionManager} implementation. + +@item +Jan Roehrich for @code{BasicTreeUI} and @code{JTree} fixes. + +@item +Julian Scheid for documentation updates and gjdoc support. + +@item +Christian Schlichtherle for zip fixes and cleanups. + +@item +Robert Schuster for documentation updates and beans fixes, +@code{TreeNode} enumerations and @code{ActionCommand} and various +fixes, XML and URL, AWT and Free Swing bugfixes. + +@item +Keith Seitz for lots of JDWP work. + +@item +Christian Thalinger for 64-bit cleanups, Configuration and VM +interface fixes and @code{CACAO} integration, @code{fdlibm} updates. + +@item +Gael Thomas for @code{VMClassLoader} boot packages support suggestions. + +@item +Andreas Tobler for Darwin and Solaris testing and fixing, @code{Qt4} +support for Darwin/OS X, @code{Graphics2D} support, @code{gtk+} +updates. + +@item +Dalibor Topic for better @code{DEBUG} support, build cleanups and +Kaffe integration. @code{Qt4} build infrastructure, @code{SHA1PRNG} +and @code{GdkPixbugDecoder} updates. + +@item +Tom Tromey for Eclipse integration, generics work, lots of bugfixes +and gcj integration including coordinating The Big Merge. + +@item +Mark Wielaard for bugfixes, packaging and release management, +@code{Clipboard} implementation, system call interrupts and network +timeouts and @code{GdkPixpufDecoder} fixes. + +@end itemize + + +In addition to the above, all of which also contributed time and energy in +testing GCC, we would like to thank the following for their contributions +to testing: + +@itemize @bullet +@item +Michael Abd-El-Malek + +@item +Thomas Arend + +@item +Bonzo Armstrong + +@item +Steven Ashe + +@item +Chris Baldwin + +@item +David Billinghurst + +@item +Jim Blandy + +@item +Stephane Bortzmeyer + +@item +Horst von Brand + +@item +Frank Braun + +@item +Rodney Brown + +@item +Sidney Cadot + +@item +Bradford Castalia + +@item +Jonathan Corbet + +@item +Ralph Doncaster + +@item +Richard Emberson + +@item +Levente Farkas + +@item +Graham Fawcett + +@item +Mark Fernyhough + +@item +Robert A. French + +@item +J@"orgen Freyh + +@item +Mark K. Gardner + +@item +Charles-Antoine Gauthier + +@item +Yung Shing Gene + +@item +David Gilbert + +@item +Simon Gornall + +@item +Fred Gray + +@item +John Griffin + +@item +Patrik Hagglund + +@item +Phil Hargett + +@item +Amancio Hasty + +@item +Takafumi Hayashi + +@item +Bryan W. Headley + +@item +Kevin B. Hendricks + +@item +Joep Jansen + +@item +Christian Joensson + +@item +Michel Kern + +@item +David Kidd + +@item +Tobias Kuipers + +@item +Anand Krishnaswamy + +@item +A. O. V. Le Blanc + +@item +llewelly + +@item +Damon Love + +@item +Brad Lucier + +@item +Matthias Klose + +@item +Martin Knoblauch + +@item +Rick Lutowski + +@item +Jesse Macnish + +@item +Stefan Morrell + +@item +Anon A. Mous + +@item +Matthias Mueller + +@item +Pekka Nikander + +@item +Rick Niles + +@item +Jon Olson + +@item +Magnus Persson + +@item +Chris Pollard + +@item +Richard Polton + +@item +Derk Reefman + +@item +David Rees + +@item +Paul Reilly + +@item +Tom Reilly + +@item +Torsten Rueger + +@item +Danny Sadinoff + +@item +Marc Schifer + +@item +Erik Schnetter + +@item +Wayne K. Schroll + +@item +David Schuler + +@item +Vin Shelton + +@item +Tim Souder + +@item +Adam Sulmicki + +@item +Bill Thorson + +@item +George Talbot + +@item +Pedro A. M. Vazquez + +@item +Gregory Warnes + +@item +Ian Watson + +@item +David E. Young + +@item +And many others +@end itemize + +And finally we'd like to thank everyone who uses the compiler, submits bug +reports and generally reminds us why we're doing this work in the first place. diff --git a/gcc-4.2.1-5666.3/gcc/doc/contribute.texi b/gcc-4.2.1-5666.3/gcc/doc/contribute.texi new file mode 100644 index 000000000..55049f1b7 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/contribute.texi @@ -0,0 +1,25 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2004, 2006 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Contributing +@chapter Contributing to GCC Development + +If you would like to help pretest GCC releases to assure they work well, +current development sources are available by SVN (see +@uref{http://gcc.gnu.org/svn.html}). Source and binary snapshots are +also available for FTP; see @uref{http://gcc.gnu.org/snapshots.html}. + +If you would like to work on improvements to GCC, please read the +advice at these URLs: + +@smallexample +@uref{http://gcc.gnu.org/contribute.html} +@uref{http://gcc.gnu.org/contributewhy.html} +@end smallexample + +@noindent +for information on how to make useful contributions and avoid +duplication of effort. Suggested projects are listed at +@uref{http://gcc.gnu.org/projects/}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/cpp.texi b/gcc-4.2.1-5666.3/gcc/doc/cpp.texi new file mode 100644 index 000000000..49c1c5fd8 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/cpp.texi @@ -0,0 +1,4288 @@ +\input texinfo +@setfilename cpp.info +@settitle The C Preprocessor +@setchapternewpage off +@c @smallbook +@c @cropmarks +@c @finalout + +@include gcc-common.texi + +@copying +@c man begin COPYRIGHT +Copyright @copyright{} 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, +1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 +Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.1 or +any later version published by the Free Software Foundation. A copy of +the license is included in the +@c man end +section entitled ``GNU Free Documentation License''. +@ignore +@c man begin COPYRIGHT +man page gfdl(7). +@c man end +@end ignore + +@c man begin COPYRIGHT +This manual contains no Invariant Sections. The Front-Cover Texts are +(a) (see below), and the Back-Cover Texts are (b) (see below). + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@c man end +@end copying + +@c Create a separate index for command line options. +@defcodeindex op +@syncodeindex vr op + +@c Used in cppopts.texi and cppenv.texi. +@set cppmanual + +@ifinfo +@dircategory Software development +@direntry +* Cpp: (cpp). The GNU C preprocessor. +@end direntry +@end ifinfo + +@titlepage +@title The C Preprocessor +@versionsubtitle +@author Richard M. Stallman, Zachary Weinberg +@page +@c There is a fill at the bottom of the page, so we need a filll to +@c override it. +@vskip 0pt plus 1filll +@insertcopying +@end titlepage +@contents +@page + +@ifnottex +@node Top +@top +The C preprocessor implements the macro language used to transform C, +C++, and Objective-C programs before they are compiled. It can also be +useful on its own. + +@menu +* Overview:: +* Header Files:: +* Macros:: +* Conditionals:: +* Diagnostics:: +* Line Control:: +* Pragmas:: +* Other Directives:: +* Preprocessor Output:: +* Traditional Mode:: +* Implementation Details:: +* Invocation:: +* Environment Variables:: +* GNU Free Documentation License:: +* Index of Directives:: +* Option Index:: +* Concept Index:: + +@detailmenu + --- The Detailed Node Listing --- + +Overview + +* Character sets:: +* Initial processing:: +* Tokenization:: +* The preprocessing language:: + +Header Files + +* Include Syntax:: +* Include Operation:: +* Search Path:: +* Once-Only Headers:: +* Computed Includes:: +* Wrapper Headers:: +* System Headers:: + +Macros + +* Object-like Macros:: +* Function-like Macros:: +* Macro Arguments:: +* Stringification:: +* Concatenation:: +* Variadic Macros:: +* Predefined Macros:: +* Undefining and Redefining Macros:: +* Directives Within Macro Arguments:: +* Macro Pitfalls:: + +Predefined Macros + +* Standard Predefined Macros:: +* Common Predefined Macros:: +* System-specific Predefined Macros:: +* C++ Named Operators:: + +Macro Pitfalls + +* Misnesting:: +* Operator Precedence Problems:: +* Swallowing the Semicolon:: +* Duplication of Side Effects:: +* Self-Referential Macros:: +* Argument Prescan:: +* Newlines in Arguments:: + +Conditionals + +* Conditional Uses:: +* Conditional Syntax:: +* Deleted Code:: + +Conditional Syntax + +* Ifdef:: +* If:: +* Defined:: +* Else:: +* Elif:: + +Implementation Details + +* Implementation-defined behavior:: +* Implementation limits:: +* Obsolete Features:: +* Differences from previous versions:: + +Obsolete Features + +* Assertions:: +* Obsolete once-only headers:: + +@end detailmenu +@end menu + +@insertcopying +@end ifnottex + +@node Overview +@chapter Overview +@c man begin DESCRIPTION +The C preprocessor, often known as @dfn{cpp}, is a @dfn{macro processor} +that is used automatically by the C compiler to transform your program +before compilation. It is called a macro processor because it allows +you to define @dfn{macros}, which are brief abbreviations for longer +constructs. + +The C preprocessor is intended to be used only with C, C++, and +Objective-C source code. In the past, it has been abused as a general +text processor. It will choke on input which does not obey C's lexical +rules. For example, apostrophes will be interpreted as the beginning of +character constants, and cause errors. Also, you cannot rely on it +preserving characteristics of the input which are not significant to +C-family languages. If a Makefile is preprocessed, all the hard tabs +will be removed, and the Makefile will not work. + +Having said that, you can often get away with using cpp on things which +are not C@. Other Algol-ish programming languages are often safe +(Pascal, Ada, etc.) So is assembly, with caution. @option{-traditional-cpp} +mode preserves more white space, and is otherwise more permissive. Many +of the problems can be avoided by writing C or C++ style comments +instead of native language comments, and keeping macros simple. + +Wherever possible, you should use a preprocessor geared to the language +you are writing in. Modern versions of the GNU assembler have macro +facilities. Most high level programming languages have their own +conditional compilation and inclusion mechanism. If all else fails, +try a true general text processor, such as GNU M4. + +C preprocessors vary in some details. This manual discusses the GNU C +preprocessor, which provides a small superset of the features of ISO +Standard C@. In its default mode, the GNU C preprocessor does not do a +few things required by the standard. These are features which are +rarely, if ever, used, and may cause surprising changes to the meaning +of a program which does not expect them. To get strict ISO Standard C, +you should use the @option{-std=c89} or @option{-std=c99} options, depending +on which version of the standard you want. To get all the mandatory +diagnostics, you must also use @option{-pedantic}. @xref{Invocation}. + +This manual describes the behavior of the ISO preprocessor. To +minimize gratuitous differences, where the ISO preprocessor's +behavior does not conflict with traditional semantics, the +traditional preprocessor should behave the same way. The various +differences that do exist are detailed in the section @ref{Traditional +Mode}. + +For clarity, unless noted otherwise, references to @samp{CPP} in this +manual refer to GNU CPP@. +@c man end + +@menu +* Character sets:: +* Initial processing:: +* Tokenization:: +* The preprocessing language:: +@end menu + +@node Character sets +@section Character sets + +Source code character set processing in C and related languages is +rather complicated. The C standard discusses two character sets, but +there are really at least four. + +The files input to CPP might be in any character set at all. CPP's +very first action, before it even looks for line boundaries, is to +convert the file into the character set it uses for internal +processing. That set is what the C standard calls the @dfn{source} +character set. It must be isomorphic with ISO 10646, also known as +Unicode. CPP uses the UTF-8 encoding of Unicode. + +The character sets of the input files are specified using the +@option{-finput-charset=} option. + +All preprocessing work (the subject of the rest of this manual) is +carried out in the source character set. If you request textual +output from the preprocessor with the @option{-E} option, it will be +in UTF-8. + +After preprocessing is complete, string and character constants are +converted again, into the @dfn{execution} character set. This +character set is under control of the user; the default is UTF-8, +matching the source character set. Wide string and character +constants have their own character set, which is not called out +specifically in the standard. Again, it is under control of the user. +The default is UTF-16 or UTF-32, whichever fits in the target's +@code{wchar_t} type, in the target machine's byte +order.@footnote{UTF-16 does not meet the requirements of the C +standard for a wide character set, but the choice of 16-bit +@code{wchar_t} is enshrined in some system ABIs so we cannot fix +this.} Octal and hexadecimal escape sequences do not undergo +conversion; @t{'\x12'} has the value 0x12 regardless of the currently +selected execution character set. All other escapes are replaced by +the character in the source character set that they represent, then +converted to the execution character set, just like unescaped +characters. + +Unless the experimental @option{-fextended-identifiers} option is used, +GCC does not permit the use of characters outside the ASCII range, nor +@samp{\u} and @samp{\U} escapes, in identifiers. Even with that +option, characters outside the ASCII range can only be specified with +the @samp{\u} and @samp{\U} escapes, not used directly in identifiers. + +@node Initial processing +@section Initial processing + +The preprocessor performs a series of textual transformations on its +input. These happen before all other processing. Conceptually, they +happen in a rigid order, and the entire file is run through each +transformation before the next one begins. CPP actually does them +all at once, for performance reasons. These transformations correspond +roughly to the first three ``phases of translation'' described in the C +standard. + +@enumerate +@item +@cindex line endings +The input file is read into memory and broken into lines. + +Different systems use different conventions to indicate the end of a +line. GCC accepts the ASCII control sequences @kbd{LF}, @kbd{@w{CR +LF}} and @kbd{CR} as end-of-line markers. These are the canonical +sequences used by Unix, DOS and VMS, and the classic Mac OS (before +OSX) respectively. You may therefore safely copy source code written +on any of those systems to a different one and use it without +conversion. (GCC may lose track of the current line number if a file +doesn't consistently use one convention, as sometimes happens when it +is edited on computers with different conventions that share a network +file system.) + +If the last line of any input file lacks an end-of-line marker, the end +of the file is considered to implicitly supply one. The C standard says +that this condition provokes undefined behavior, so GCC will emit a +warning message. + +@item +@cindex trigraphs +@anchor{trigraphs}If trigraphs are enabled, they are replaced by their +corresponding single characters. By default GCC ignores trigraphs, +but if you request a strictly conforming mode with the @option{-std} +option, or you specify the @option{-trigraphs} option, then it +converts them. + +These are nine three-character sequences, all starting with @samp{??}, +that are defined by ISO C to stand for single characters. They permit +obsolete systems that lack some of C's punctuation to use C@. For +example, @samp{??/} stands for @samp{\}, so @t{'??/n'} is a character +constant for a newline. + +Trigraphs are not popular and many compilers implement them +incorrectly. Portable code should not rely on trigraphs being either +converted or ignored. With @option{-Wtrigraphs} GCC will warn you +when a trigraph may change the meaning of your program if it were +converted. @xref{Wtrigraphs}. + +In a string constant, you can prevent a sequence of question marks +from being confused with a trigraph by inserting a backslash between +the question marks, or by separating the string literal at the +trigraph and making use of string literal concatenation. @t{"(??\?)"} +is the string @samp{(???)}, not @samp{(?]}. Traditional C compilers +do not recognize these idioms. + +The nine trigraphs and their replacements are + +@smallexample +Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??- +Replacement: [ ] @{ @} # \ ^ | ~ +@end smallexample + +@item +@cindex continued lines +@cindex backslash-newline +Continued lines are merged into one long line. + +A continued line is a line which ends with a backslash, @samp{\}. The +backslash is removed and the following line is joined with the current +one. No space is inserted, so you may split a line anywhere, even in +the middle of a word. (It is generally more readable to split lines +only at white space.) + +The trailing backslash on a continued line is commonly referred to as a +@dfn{backslash-newline}. + +If there is white space between a backslash and the end of a line, that +is still a continued line. However, as this is usually the result of an +editing mistake, and many compilers will not accept it as a continued +line, GCC will warn you about it. + +@item +@cindex comments +@cindex line comments +@cindex block comments +All comments are replaced with single spaces. + +There are two kinds of comments. @dfn{Block comments} begin with +@samp{/*} and continue until the next @samp{*/}. Block comments do not +nest: + +@smallexample +/* @r{this is} /* @r{one comment} */ @r{text outside comment} +@end smallexample + +@dfn{Line comments} begin with @samp{//} and continue to the end of the +current line. Line comments do not nest either, but it does not matter, +because they would end in the same place anyway. + +@smallexample +// @r{this is} // @r{one comment} +@r{text outside comment} +@end smallexample +@end enumerate + +It is safe to put line comments inside block comments, or vice versa. + +@smallexample +@group +/* @r{block comment} + // @r{contains line comment} + @r{yet more comment} + */ @r{outside comment} + +// @r{line comment} /* @r{contains block comment} */ +@end group +@end smallexample + +But beware of commenting out one end of a block comment with a line +comment. + +@smallexample +@group + // @r{l.c.} /* @r{block comment begins} + @r{oops! this isn't a comment anymore} */ +@end group +@end smallexample + +Comments are not recognized within string literals. +@t{@w{"/* blah */"}} is the string constant @samp{@w{/* blah */}}, not +an empty string. + +Line comments are not in the 1989 edition of the C standard, but they +are recognized by GCC as an extension. In C++ and in the 1999 edition +of the C standard, they are an official part of the language. + +Since these transformations happen before all other processing, you can +split a line mechanically with backslash-newline anywhere. You can +comment out the end of a line. You can continue a line comment onto the +next line with backslash-newline. You can even split @samp{/*}, +@samp{*/}, and @samp{//} onto multiple lines with backslash-newline. +For example: + +@smallexample +@group +/\ +* +*/ # /* +*/ defi\ +ne FO\ +O 10\ +20 +@end group +@end smallexample + +@noindent +is equivalent to @code{@w{#define FOO 1020}}. All these tricks are +extremely confusing and should not be used in code intended to be +readable. + +There is no way to prevent a backslash at the end of a line from being +interpreted as a backslash-newline. This cannot affect any correct +program, however. + +@node Tokenization +@section Tokenization + +@cindex tokens +@cindex preprocessing tokens +After the textual transformations are finished, the input file is +converted into a sequence of @dfn{preprocessing tokens}. These mostly +correspond to the syntactic tokens used by the C compiler, but there are +a few differences. White space separates tokens; it is not itself a +token of any kind. Tokens do not have to be separated by white space, +but it is often necessary to avoid ambiguities. + +When faced with a sequence of characters that has more than one possible +tokenization, the preprocessor is greedy. It always makes each token, +starting from the left, as big as possible before moving on to the next +token. For instance, @code{a+++++b} is interpreted as +@code{@w{a ++ ++ + b}}, not as @code{@w{a ++ + ++ b}}, even though the +latter tokenization could be part of a valid C program and the former +could not. + +Once the input file is broken into tokens, the token boundaries never +change, except when the @samp{##} preprocessing operator is used to paste +tokens together. @xref{Concatenation}. For example, + +@smallexample +@group +#define foo() bar +foo()baz + @expansion{} bar baz +@emph{not} + @expansion{} barbaz +@end group +@end smallexample + +The compiler does not re-tokenize the preprocessor's output. Each +preprocessing token becomes one compiler token. + +@cindex identifiers +Preprocessing tokens fall into five broad classes: identifiers, +preprocessing numbers, string literals, punctuators, and other. An +@dfn{identifier} is the same as an identifier in C: any sequence of +letters, digits, or underscores, which begins with a letter or +underscore. Keywords of C have no significance to the preprocessor; +they are ordinary identifiers. You can define a macro whose name is a +keyword, for instance. The only identifier which can be considered a +preprocessing keyword is @code{defined}. @xref{Defined}. + +This is mostly true of other languages which use the C preprocessor. +However, a few of the keywords of C++ are significant even in the +preprocessor. @xref{C++ Named Operators}. + +In the 1999 C standard, identifiers may contain letters which are not +part of the ``basic source character set'', at the implementation's +discretion (such as accented Latin letters, Greek letters, or Chinese +ideograms). This may be done with an extended character set, or the +@samp{\u} and @samp{\U} escape sequences. The implementation of this +feature in GCC is experimental; such characters are only accepted in +the @samp{\u} and @samp{\U} forms and only if +@option{-fextended-identifiers} is used. + +As an extension, GCC treats @samp{$} as a letter. This is for +compatibility with some systems, such as VMS, where @samp{$} is commonly +used in system-defined function and object names. @samp{$} is not a +letter in strictly conforming mode, or if you specify the @option{-$} +option. @xref{Invocation}. + +@cindex numbers +@cindex preprocessing numbers +A @dfn{preprocessing number} has a rather bizarre definition. The +category includes all the normal integer and floating point constants +one expects of C, but also a number of other things one might not +initially recognize as a number. Formally, preprocessing numbers begin +with an optional period, a required decimal digit, and then continue +with any sequence of letters, digits, underscores, periods, and +exponents. Exponents are the two-character sequences @samp{e+}, +@samp{e-}, @samp{E+}, @samp{E-}, @samp{p+}, @samp{p-}, @samp{P+}, and +@samp{P-}. (The exponents that begin with @samp{p} or @samp{P} are new +to C99. They are used for hexadecimal floating-point constants.) + +The purpose of this unusual definition is to isolate the preprocessor +from the full complexity of numeric constants. It does not have to +distinguish between lexically valid and invalid floating-point numbers, +which is complicated. The definition also permits you to split an +identifier at any position and get exactly two tokens, which can then be +pasted back together with the @samp{##} operator. + +It's possible for preprocessing numbers to cause programs to be +misinterpreted. For example, @code{0xE+12} is a preprocessing number +which does not translate to any valid numeric constant, therefore a +syntax error. It does not mean @code{@w{0xE + 12}}, which is what you +might have intended. + +@cindex string literals +@cindex string constants +@cindex character constants +@cindex header file names +@c the @: prevents makeinfo from turning '' into ". +@dfn{String literals} are string constants, character constants, and +header file names (the argument of @samp{#include}).@footnote{The C +standard uses the term @dfn{string literal} to refer only to what we are +calling @dfn{string constants}.} String constants and character +constants are straightforward: @t{"@dots{}"} or @t{'@dots{}'}. In +either case embedded quotes should be escaped with a backslash: +@t{'\'@:'} is the character constant for @samp{'}. There is no limit on +the length of a character constant, but the value of a character +constant that contains more than one character is +implementation-defined. @xref{Implementation Details}. + +Header file names either look like string constants, @t{"@dots{}"}, or are +written with angle brackets instead, @t{<@dots{}>}. In either case, +backslash is an ordinary character. There is no way to escape the +closing quote or angle bracket. The preprocessor looks for the header +file in different places depending on which form you use. @xref{Include +Operation}. + +No string literal may extend past the end of a line. Older versions +of GCC accepted multi-line string constants. You may use continued +lines instead, or string constant concatenation. @xref{Differences +from previous versions}. + +@cindex punctuators +@cindex digraphs +@cindex alternative tokens +@dfn{Punctuators} are all the usual bits of punctuation which are +meaningful to C and C++. All but three of the punctuation characters in +ASCII are C punctuators. The exceptions are @samp{@@}, @samp{$}, and +@samp{`}. In addition, all the two- and three-character operators are +punctuators. There are also six @dfn{digraphs}, which the C++ standard +calls @dfn{alternative tokens}, which are merely alternate ways to spell +other punctuators. This is a second attempt to work around missing +punctuation in obsolete systems. It has no negative side effects, +unlike trigraphs, but does not cover as much ground. The digraphs and +their corresponding normal punctuators are: + +@smallexample +Digraph: <% %> <: :> %: %:%: +Punctuator: @{ @} [ ] # ## +@end smallexample + +@cindex other tokens +Any other single character is considered ``other''. It is passed on to +the preprocessor's output unmolested. The C compiler will almost +certainly reject source code containing ``other'' tokens. In ASCII, the +only other characters are @samp{@@}, @samp{$}, @samp{`}, and control +characters other than NUL (all bits zero). (Note that @samp{$} is +normally considered a letter.) All characters with the high bit set +(numeric range 0x7F--0xFF) are also ``other'' in the present +implementation. This will change when proper support for international +character sets is added to GCC@. + +NUL is a special case because of the high probability that its +appearance is accidental, and because it may be invisible to the user +(many terminals do not display NUL at all). Within comments, NULs are +silently ignored, just as any other character would be. In running +text, NUL is considered white space. For example, these two directives +have the same meaning. + +@smallexample +#define X^@@1 +#define X 1 +@end smallexample + +@noindent +(where @samp{^@@} is ASCII NUL)@. Within string or character constants, +NULs are preserved. In the latter two cases the preprocessor emits a +warning message. + +@node The preprocessing language +@section The preprocessing language +@cindex directives +@cindex preprocessing directives +@cindex directive line +@cindex directive name + +After tokenization, the stream of tokens may simply be passed straight +to the compiler's parser. However, if it contains any operations in the +@dfn{preprocessing language}, it will be transformed first. This stage +corresponds roughly to the standard's ``translation phase 4'' and is +what most people think of as the preprocessor's job. + +The preprocessing language consists of @dfn{directives} to be executed +and @dfn{macros} to be expanded. Its primary capabilities are: + +@itemize @bullet +@item +Inclusion of header files. These are files of declarations that can be +substituted into your program. + +@item +Macro expansion. You can define @dfn{macros}, which are abbreviations +for arbitrary fragments of C code. The preprocessor will replace the +macros with their definitions throughout the program. Some macros are +automatically defined for you. + +@item +Conditional compilation. You can include or exclude parts of the +program according to various conditions. + +@item +Line control. If you use a program to combine or rearrange source files +into an intermediate file which is then compiled, you can use line +control to inform the compiler where each source line originally came +from. + +@item +Diagnostics. You can detect problems at compile time and issue errors +or warnings. +@end itemize + +There are a few more, less useful, features. + +Except for expansion of predefined macros, all these operations are +triggered with @dfn{preprocessing directives}. Preprocessing directives +are lines in your program that start with @samp{#}. Whitespace is +allowed before and after the @samp{#}. The @samp{#} is followed by an +identifier, the @dfn{directive name}. It specifies the operation to +perform. Directives are commonly referred to as @samp{#@var{name}} +where @var{name} is the directive name. For example, @samp{#define} is +the directive that defines a macro. + +The @samp{#} which begins a directive cannot come from a macro +expansion. Also, the directive name is not macro expanded. Thus, if +@code{foo} is defined as a macro expanding to @code{define}, that does +not make @samp{#foo} a valid preprocessing directive. + +The set of valid directive names is fixed. Programs cannot define new +preprocessing directives. + +Some directives require arguments; these make up the rest of the +directive line and must be separated from the directive name by +whitespace. For example, @samp{#define} must be followed by a macro +name and the intended expansion of the macro. + +A preprocessing directive cannot cover more than one line. The line +may, however, be continued with backslash-newline, or by a block comment +which extends past the end of the line. In either case, when the +directive is processed, the continuations have already been merged with +the first line to make one long line. + +@node Header Files +@chapter Header Files + +@cindex header file +A header file is a file containing C declarations and macro definitions +(@pxref{Macros}) to be shared between several source files. You request +the use of a header file in your program by @dfn{including} it, with the +C preprocessing directive @samp{#include}. + +Header files serve two purposes. + +@itemize @bullet +@item +@cindex system header files +System header files declare the interfaces to parts of the operating +system. You include them in your program to supply the definitions and +declarations you need to invoke system calls and libraries. + +@item +Your own header files contain declarations for interfaces between the +source files of your program. Each time you have a group of related +declarations and macro definitions all or most of which are needed in +several different source files, it is a good idea to create a header +file for them. +@end itemize + +Including a header file produces the same results as copying the header +file into each source file that needs it. Such copying would be +time-consuming and error-prone. With a header file, the related +declarations appear in only one place. If they need to be changed, they +can be changed in one place, and programs that include the header file +will automatically use the new version when next recompiled. The header +file eliminates the labor of finding and changing all the copies as well +as the risk that a failure to find one copy will result in +inconsistencies within a program. + +In C, the usual convention is to give header files names that end with +@file{.h}. It is most portable to use only letters, digits, dashes, and +underscores in header file names, and at most one dot. + +@menu +* Include Syntax:: +* Include Operation:: +* Search Path:: +* Once-Only Headers:: +* Computed Includes:: +* Wrapper Headers:: +* System Headers:: +@end menu + +@node Include Syntax +@section Include Syntax + +@findex #include +Both user and system header files are included using the preprocessing +directive @samp{#include}. It has two variants: + +@table @code +@item #include <@var{file}> +This variant is used for system header files. It searches for a file +named @var{file} in a standard list of system directories. You can prepend +directories to this list with the @option{-I} option (@pxref{Invocation}). + +@item #include "@var{file}" +This variant is used for header files of your own program. It +searches for a file named @var{file} first in the directory containing +the current file, then in the quote directories and then the same +directories used for @code{<@var{file}>}. You can prepend directories +to the list of quote directories with the @option{-iquote} option. +@end table + +The argument of @samp{#include}, whether delimited with quote marks or +angle brackets, behaves like a string constant in that comments are not +recognized, and macro names are not expanded. Thus, @code{@w{#include +<x/*y>}} specifies inclusion of a system header file named @file{x/*y}. + +However, if backslashes occur within @var{file}, they are considered +ordinary text characters, not escape characters. None of the character +escape sequences appropriate to string constants in C are processed. +Thus, @code{@w{#include "x\n\\y"}} specifies a filename containing three +backslashes. (Some systems interpret @samp{\} as a pathname separator. +All of these also interpret @samp{/} the same way. It is most portable +to use only @samp{/}.) + +It is an error if there is anything (other than comments) on the line +after the file name. + +@node Include Operation +@section Include Operation + +The @samp{#include} directive works by directing the C preprocessor to +scan the specified file as input before continuing with the rest of the +current file. The output from the preprocessor contains the output +already generated, followed by the output resulting from the included +file, followed by the output that comes from the text after the +@samp{#include} directive. For example, if you have a header file +@file{header.h} as follows, + +@smallexample +char *test (void); +@end smallexample + +@noindent +and a main program called @file{program.c} that uses the header file, +like this, + +@smallexample +int x; +#include "header.h" + +int +main (void) +@{ + puts (test ()); +@} +@end smallexample + +@noindent +the compiler will see the same token stream as it would if +@file{program.c} read + +@smallexample +int x; +char *test (void); + +int +main (void) +@{ + puts (test ()); +@} +@end smallexample + +Included files are not limited to declarations and macro definitions; +those are merely the typical uses. Any fragment of a C program can be +included from another file. The include file could even contain the +beginning of a statement that is concluded in the containing file, or +the end of a statement that was started in the including file. However, +an included file must consist of complete tokens. Comments and string +literals which have not been closed by the end of an included file are +invalid. For error recovery, they are considered to end at the end of +the file. + +To avoid confusion, it is best if header files contain only complete +syntactic units---function declarations or definitions, type +declarations, etc. + +The line following the @samp{#include} directive is always treated as a +separate line by the C preprocessor, even if the included file lacks a +final newline. + +@node Search Path +@section Search Path + +GCC looks in several different places for headers. On a normal Unix +system, if you do not instruct it otherwise, it will look for headers +requested with @code{@w{#include <@var{file}>}} in: + +@smallexample +/usr/local/include +@var{libdir}/gcc/@var{target}/@var{version}/include +/usr/@var{target}/include +/usr/include +@end smallexample + +For C++ programs, it will also look in @file{/usr/include/g++-v3}, +first. In the above, @var{target} is the canonical name of the system +GCC was configured to compile code for; often but not always the same as +the canonical name of the system it runs on. @var{version} is the +version of GCC in use. + +You can add to this list with the @option{-I@var{dir}} command line +option. All the directories named by @option{-I} are searched, in +left-to-right order, @emph{before} the default directories. The only +exception is when @file{dir} is already searched by default. In +this case, the option is ignored and the search order for system +directories remains unchanged. + +Duplicate directories are removed from the quote and bracket search +chains before the two chains are merged to make the final search chain. +Thus, it is possible for a directory to occur twice in the final search +chain if it was specified in both the quote and bracket chains. + +You can prevent GCC from searching any of the default directories with +the @option{-nostdinc} option. This is useful when you are compiling an +operating system kernel or some other program that does not use the +standard C library facilities, or the standard C library itself. +@option{-I} options are not ignored as described above when +@option{-nostdinc} is in effect. + +GCC looks for headers requested with @code{@w{#include "@var{file}"}} +first in the directory containing the current file, then in the +directories as specified by @option{-iquote} options, then in the same +places it would have looked for a header requested with angle +brackets. For example, if @file{/usr/include/sys/stat.h} contains +@code{@w{#include "types.h"}}, GCC looks for @file{types.h} first in +@file{/usr/include/sys}, then in its usual search path. + +@samp{#line} (@pxref{Line Control}) does not change GCC's idea of the +directory containing the current file. + +You may put @option{-I-} at any point in your list of @option{-I} options. +This has two effects. First, directories appearing before the +@option{-I-} in the list are searched only for headers requested with +quote marks. Directories after @option{-I-} are searched for all +headers. Second, the directory containing the current file is not +searched for anything, unless it happens to be one of the directories +named by an @option{-I} switch. @option{-I-} is deprecated, @option{-iquote} +should be used instead. + +@option{-I. -I-} is not the same as no @option{-I} options at all, and does +not cause the same behavior for @samp{<>} includes that @samp{""} +includes get with no special options. @option{-I.} searches the +compiler's current working directory for header files. That may or may +not be the same as the directory containing the current file. + +If you need to look for headers in a directory named @file{-}, write +@option{-I./-}. + +There are several more ways to adjust the header search path. They are +generally less useful. @xref{Invocation}. + +@node Once-Only Headers +@section Once-Only Headers +@cindex repeated inclusion +@cindex including just once +@cindex wrapper @code{#ifndef} + +If a header file happens to be included twice, the compiler will process +its contents twice. This is very likely to cause an error, e.g.@: when the +compiler sees the same structure definition twice. Even if it does not, +it will certainly waste time. + +The standard way to prevent this is to enclose the entire real contents +of the file in a conditional, like this: + +@smallexample +@group +/* File foo. */ +#ifndef FILE_FOO_SEEN +#define FILE_FOO_SEEN + +@var{the entire file} + +#endif /* !FILE_FOO_SEEN */ +@end group +@end smallexample + +This construct is commonly known as a @dfn{wrapper #ifndef}. +When the header is included again, the conditional will be false, +because @code{FILE_FOO_SEEN} is defined. The preprocessor will skip +over the entire contents of the file, and the compiler will not see it +twice. + +CPP optimizes even further. It remembers when a header file has a +wrapper @samp{#ifndef}. If a subsequent @samp{#include} specifies that +header, and the macro in the @samp{#ifndef} is still defined, it does +not bother to rescan the file at all. + +You can put comments outside the wrapper. They will not interfere with +this optimization. + +@cindex controlling macro +@cindex guard macro +The macro @code{FILE_FOO_SEEN} is called the @dfn{controlling macro} or +@dfn{guard macro}. In a user header file, the macro name should not +begin with @samp{_}. In a system header file, it should begin with +@samp{__} to avoid conflicts with user programs. In any kind of header +file, the macro name should contain the name of the file and some +additional text, to avoid conflicts with other header files. + +@node Computed Includes +@section Computed Includes +@cindex computed includes +@cindex macros in include + +Sometimes it is necessary to select one of several different header +files to be included into your program. They might specify +configuration parameters to be used on different sorts of operating +systems, for instance. You could do this with a series of conditionals, + +@smallexample +#if SYSTEM_1 +# include "system_1.h" +#elif SYSTEM_2 +# include "system_2.h" +#elif SYSTEM_3 +@dots{} +#endif +@end smallexample + +That rapidly becomes tedious. Instead, the preprocessor offers the +ability to use a macro for the header name. This is called a +@dfn{computed include}. Instead of writing a header name as the direct +argument of @samp{#include}, you simply put a macro name there instead: + +@smallexample +#define SYSTEM_H "system_1.h" +@dots{} +#include SYSTEM_H +@end smallexample + +@noindent +@code{SYSTEM_H} will be expanded, and the preprocessor will look for +@file{system_1.h} as if the @samp{#include} had been written that way +originally. @code{SYSTEM_H} could be defined by your Makefile with a +@option{-D} option. + +You must be careful when you define the macro. @samp{#define} saves +tokens, not text. The preprocessor has no way of knowing that the macro +will be used as the argument of @samp{#include}, so it generates +ordinary tokens, not a header name. This is unlikely to cause problems +if you use double-quote includes, which are close enough to string +constants. If you use angle brackets, however, you may have trouble. + +The syntax of a computed include is actually a bit more general than the +above. If the first non-whitespace character after @samp{#include} is +not @samp{"} or @samp{<}, then the entire line is macro-expanded +like running text would be. + +If the line expands to a single string constant, the contents of that +string constant are the file to be included. CPP does not re-examine the +string for embedded quotes, but neither does it process backslash +escapes in the string. Therefore + +@smallexample +#define HEADER "a\"b" +#include HEADER +@end smallexample + +@noindent +looks for a file named @file{a\"b}. CPP searches for the file according +to the rules for double-quoted includes. + +If the line expands to a token stream beginning with a @samp{<} token +and including a @samp{>} token, then the tokens between the @samp{<} and +the first @samp{>} are combined to form the filename to be included. +Any whitespace between tokens is reduced to a single space; then any +space after the initial @samp{<} is retained, but a trailing space +before the closing @samp{>} is ignored. CPP searches for the file +according to the rules for angle-bracket includes. + +In either case, if there are any tokens on the line after the file name, +an error occurs and the directive is not processed. It is also an error +if the result of expansion does not match either of the two expected +forms. + +These rules are implementation-defined behavior according to the C +standard. To minimize the risk of different compilers interpreting your +computed includes differently, we recommend you use only a single +object-like macro which expands to a string constant. This will also +minimize confusion for people reading your program. + +@node Wrapper Headers +@section Wrapper Headers +@cindex wrapper headers +@cindex overriding a header file +@findex #include_next + +Sometimes it is necessary to adjust the contents of a system-provided +header file without editing it directly. GCC's @command{fixincludes} +operation does this, for example. One way to do that would be to create +a new header file with the same name and insert it in the search path +before the original header. That works fine as long as you're willing +to replace the old header entirely. But what if you want to refer to +the old header from the new one? + +You cannot simply include the old header with @samp{#include}. That +will start from the beginning, and find your new header again. If your +header is not protected from multiple inclusion (@pxref{Once-Only +Headers}), it will recurse infinitely and cause a fatal error. + +You could include the old header with an absolute pathname: +@smallexample +#include "/usr/include/old-header.h" +@end smallexample +@noindent +This works, but is not clean; should the system headers ever move, you +would have to edit the new headers to match. + +There is no way to solve this problem within the C standard, but you can +use the GNU extension @samp{#include_next}. It means, ``Include the +@emph{next} file with this name''. This directive works like +@samp{#include} except in searching for the specified file: it starts +searching the list of header file directories @emph{after} the directory +in which the current file was found. + +Suppose you specify @option{-I /usr/local/include}, and the list of +directories to search also includes @file{/usr/include}; and suppose +both directories contain @file{signal.h}. Ordinary @code{@w{#include +<signal.h>}} finds the file under @file{/usr/local/include}. If that +file contains @code{@w{#include_next <signal.h>}}, it starts searching +after that directory, and finds the file in @file{/usr/include}. + +@samp{#include_next} does not distinguish between @code{<@var{file}>} +and @code{"@var{file}"} inclusion, nor does it check that the file you +specify has the same name as the current file. It simply looks for the +file named, starting with the directory in the search path after the one +where the current file was found. + +The use of @samp{#include_next} can lead to great confusion. We +recommend it be used only when there is no other alternative. In +particular, it should not be used in the headers belonging to a specific +program; it should be used only to make global corrections along the +lines of @command{fixincludes}. + +@node System Headers +@section System Headers +@cindex system header files + +The header files declaring interfaces to the operating system and +runtime libraries often cannot be written in strictly conforming C@. +Therefore, GCC gives code found in @dfn{system headers} special +treatment. All warnings, other than those generated by @samp{#warning} +(@pxref{Diagnostics}), are suppressed while GCC is processing a system +header. Macros defined in a system header are immune to a few warnings +wherever they are expanded. This immunity is granted on an ad-hoc +basis, when we find that a warning generates lots of false positives +because of code in macros defined in system headers. + +Normally, only the headers found in specific directories are considered +system headers. These directories are determined when GCC is compiled. +There are, however, two ways to make normal headers into system headers. + +The @option{-isystem} command line option adds its argument to the list of +directories to search for headers, just like @option{-I}. Any headers +found in that directory will be considered system headers. + +All directories named by @option{-isystem} are searched @emph{after} all +directories named by @option{-I}, no matter what their order was on the +command line. If the same directory is named by both @option{-I} and +@option{-isystem}, the @option{-I} option is ignored. GCC provides an +informative message when this occurs if @option{-v} is used. + +@findex #pragma GCC system_header +There is also a directive, @code{@w{#pragma GCC system_header}}, which +tells GCC to consider the rest of the current include file a system +header, no matter where it was found. Code that comes before the +@samp{#pragma} in the file will not be affected. @code{@w{#pragma GCC +system_header}} has no effect in the primary source file. + +On very old systems, some of the pre-defined system header directories +get even more special treatment. GNU C++ considers code in headers +found in those directories to be surrounded by an @code{@w{extern "C"}} +block. There is no way to request this behavior with a @samp{#pragma}, +or from the command line. + +@node Macros +@chapter Macros + +A @dfn{macro} is a fragment of code which has been given a name. +Whenever the name is used, it is replaced by the contents of the macro. +There are two kinds of macros. They differ mostly in what they look +like when they are used. @dfn{Object-like} macros resemble data objects +when used, @dfn{function-like} macros resemble function calls. + +You may define any valid identifier as a macro, even if it is a C +keyword. The preprocessor does not know anything about keywords. This +can be useful if you wish to hide a keyword such as @code{const} from an +older compiler that does not understand it. However, the preprocessor +operator @code{defined} (@pxref{Defined}) can never be defined as a +macro, and C++'s named operators (@pxref{C++ Named Operators}) cannot be +macros when you are compiling C++. + +@menu +* Object-like Macros:: +* Function-like Macros:: +* Macro Arguments:: +* Stringification:: +* Concatenation:: +* Variadic Macros:: +* Predefined Macros:: +* Undefining and Redefining Macros:: +* Directives Within Macro Arguments:: +* Macro Pitfalls:: +@end menu + +@node Object-like Macros +@section Object-like Macros +@cindex object-like macro +@cindex symbolic constants +@cindex manifest constants + +An @dfn{object-like macro} is a simple identifier which will be replaced +by a code fragment. It is called object-like because it looks like a +data object in code that uses it. They are most commonly used to give +symbolic names to numeric constants. + +@findex #define +You create macros with the @samp{#define} directive. @samp{#define} is +followed by the name of the macro and then the token sequence it should +be an abbreviation for, which is variously referred to as the macro's +@dfn{body}, @dfn{expansion} or @dfn{replacement list}. For example, + +@smallexample +#define BUFFER_SIZE 1024 +@end smallexample + +@noindent +defines a macro named @code{BUFFER_SIZE} as an abbreviation for the +token @code{1024}. If somewhere after this @samp{#define} directive +there comes a C statement of the form + +@smallexample +foo = (char *) malloc (BUFFER_SIZE); +@end smallexample + +@noindent +then the C preprocessor will recognize and @dfn{expand} the macro +@code{BUFFER_SIZE}. The C compiler will see the same tokens as it would +if you had written + +@smallexample +foo = (char *) malloc (1024); +@end smallexample + +By convention, macro names are written in uppercase. Programs are +easier to read when it is possible to tell at a glance which names are +macros. + +The macro's body ends at the end of the @samp{#define} line. You may +continue the definition onto multiple lines, if necessary, using +backslash-newline. When the macro is expanded, however, it will all +come out on one line. For example, + +@smallexample +#define NUMBERS 1, \ + 2, \ + 3 +int x[] = @{ NUMBERS @}; + @expansion{} int x[] = @{ 1, 2, 3 @}; +@end smallexample + +@noindent +The most common visible consequence of this is surprising line numbers +in error messages. + +There is no restriction on what can go in a macro body provided it +decomposes into valid preprocessing tokens. Parentheses need not +balance, and the body need not resemble valid C code. (If it does not, +you may get error messages from the C compiler when you use the macro.) + +The C preprocessor scans your program sequentially. Macro definitions +take effect at the place you write them. Therefore, the following input +to the C preprocessor + +@smallexample +foo = X; +#define X 4 +bar = X; +@end smallexample + +@noindent +produces + +@smallexample +foo = X; +bar = 4; +@end smallexample + +When the preprocessor expands a macro name, the macro's expansion +replaces the macro invocation, then the expansion is examined for more +macros to expand. For example, + +@smallexample +@group +#define TABLESIZE BUFSIZE +#define BUFSIZE 1024 +TABLESIZE + @expansion{} BUFSIZE + @expansion{} 1024 +@end group +@end smallexample + +@noindent +@code{TABLESIZE} is expanded first to produce @code{BUFSIZE}, then that +macro is expanded to produce the final result, @code{1024}. + +Notice that @code{BUFSIZE} was not defined when @code{TABLESIZE} was +defined. The @samp{#define} for @code{TABLESIZE} uses exactly the +expansion you specify---in this case, @code{BUFSIZE}---and does not +check to see whether it too contains macro names. Only when you +@emph{use} @code{TABLESIZE} is the result of its expansion scanned for +more macro names. + +This makes a difference if you change the definition of @code{BUFSIZE} +at some point in the source file. @code{TABLESIZE}, defined as shown, +will always expand using the definition of @code{BUFSIZE} that is +currently in effect: + +@smallexample +#define BUFSIZE 1020 +#define TABLESIZE BUFSIZE +#undef BUFSIZE +#define BUFSIZE 37 +@end smallexample + +@noindent +Now @code{TABLESIZE} expands (in two stages) to @code{37}. + +If the expansion of a macro contains its own name, either directly or +via intermediate macros, it is not expanded again when the expansion is +examined for more macros. This prevents infinite recursion. +@xref{Self-Referential Macros}, for the precise details. + +@node Function-like Macros +@section Function-like Macros +@cindex function-like macros + +You can also define macros whose use looks like a function call. These +are called @dfn{function-like macros}. To define a function-like macro, +you use the same @samp{#define} directive, but you put a pair of +parentheses immediately after the macro name. For example, + +@smallexample +#define lang_init() c_init() +lang_init() + @expansion{} c_init() +@end smallexample + +A function-like macro is only expanded if its name appears with a pair +of parentheses after it. If you write just the name, it is left alone. +This can be useful when you have a function and a macro of the same +name, and you wish to use the function sometimes. + +@smallexample +extern void foo(void); +#define foo() /* @r{optimized inline version} */ +@dots{} + foo(); + funcptr = foo; +@end smallexample + +Here the call to @code{foo()} will use the macro, but the function +pointer will get the address of the real function. If the macro were to +be expanded, it would cause a syntax error. + +If you put spaces between the macro name and the parentheses in the +macro definition, that does not define a function-like macro, it defines +an object-like macro whose expansion happens to begin with a pair of +parentheses. + +@smallexample +#define lang_init () c_init() +lang_init() + @expansion{} () c_init()() +@end smallexample + +The first two pairs of parentheses in this expansion come from the +macro. The third is the pair that was originally after the macro +invocation. Since @code{lang_init} is an object-like macro, it does not +consume those parentheses. + +@node Macro Arguments +@section Macro Arguments +@cindex arguments +@cindex macros with arguments +@cindex arguments in macro definitions + +Function-like macros can take @dfn{arguments}, just like true functions. +To define a macro that uses arguments, you insert @dfn{parameters} +between the pair of parentheses in the macro definition that make the +macro function-like. The parameters must be valid C identifiers, +separated by commas and optionally whitespace. + +To invoke a macro that takes arguments, you write the name of the macro +followed by a list of @dfn{actual arguments} in parentheses, separated +by commas. The invocation of the macro need not be restricted to a +single logical line---it can cross as many lines in the source file as +you wish. The number of arguments you give must match the number of +parameters in the macro definition. When the macro is expanded, each +use of a parameter in its body is replaced by the tokens of the +corresponding argument. (You need not use all of the parameters in the +macro body.) + +As an example, here is a macro that computes the minimum of two numeric +values, as it is defined in many C programs, and some uses. + +@smallexample +#define min(X, Y) ((X) < (Y) ? (X) : (Y)) + x = min(a, b); @expansion{} x = ((a) < (b) ? (a) : (b)); + y = min(1, 2); @expansion{} y = ((1) < (2) ? (1) : (2)); + z = min(a + 28, *p); @expansion{} z = ((a + 28) < (*p) ? (a + 28) : (*p)); +@end smallexample + +@noindent +(In this small example you can already see several of the dangers of +macro arguments. @xref{Macro Pitfalls}, for detailed explanations.) + +Leading and trailing whitespace in each argument is dropped, and all +whitespace between the tokens of an argument is reduced to a single +space. Parentheses within each argument must balance; a comma within +such parentheses does not end the argument. However, there is no +requirement for square brackets or braces to balance, and they do not +prevent a comma from separating arguments. Thus, + +@smallexample +macro (array[x = y, x + 1]) +@end smallexample + +@noindent +passes two arguments to @code{macro}: @code{array[x = y} and @code{x + +1]}. If you want to supply @code{array[x = y, x + 1]} as an argument, +you can write it as @code{array[(x = y, x + 1)]}, which is equivalent C +code. + +All arguments to a macro are completely macro-expanded before they are +substituted into the macro body. After substitution, the complete text +is scanned again for macros to expand, including the arguments. This rule +may seem strange, but it is carefully designed so you need not worry +about whether any function call is actually a macro invocation. You can +run into trouble if you try to be too clever, though. @xref{Argument +Prescan}, for detailed discussion. + +For example, @code{min (min (a, b), c)} is first expanded to + +@smallexample + min (((a) < (b) ? (a) : (b)), (c)) +@end smallexample + +@noindent +and then to + +@smallexample +@group +((((a) < (b) ? (a) : (b))) < (c) + ? (((a) < (b) ? (a) : (b))) + : (c)) +@end group +@end smallexample + +@noindent +(Line breaks shown here for clarity would not actually be generated.) + +@cindex empty macro arguments +You can leave macro arguments empty; this is not an error to the +preprocessor (but many macros will then expand to invalid code). +You cannot leave out arguments entirely; if a macro takes two arguments, +there must be exactly one comma at the top level of its argument list. +Here are some silly examples using @code{min}: + +@smallexample +min(, b) @expansion{} (( ) < (b) ? ( ) : (b)) +min(a, ) @expansion{} ((a ) < ( ) ? (a ) : ( )) +min(,) @expansion{} (( ) < ( ) ? ( ) : ( )) +min((,),) @expansion{} (((,)) < ( ) ? ((,)) : ( )) + +min() @error{} macro "min" requires 2 arguments, but only 1 given +min(,,) @error{} macro "min" passed 3 arguments, but takes just 2 +@end smallexample + +Whitespace is not a preprocessing token, so if a macro @code{foo} takes +one argument, @code{@w{foo ()}} and @code{@w{foo ( )}} both supply it an +empty argument. Previous GNU preprocessor implementations and +documentation were incorrect on this point, insisting that a +function-like macro that takes a single argument be passed a space if an +empty argument was required. + +Macro parameters appearing inside string literals are not replaced by +their corresponding actual arguments. + +@smallexample +#define foo(x) x, "x" +foo(bar) @expansion{} bar, "x" +@end smallexample + +@node Stringification +@section Stringification +@cindex stringification +@cindex @samp{#} operator + +Sometimes you may want to convert a macro argument into a string +constant. Parameters are not replaced inside string constants, but you +can use the @samp{#} preprocessing operator instead. When a macro +parameter is used with a leading @samp{#}, the preprocessor replaces it +with the literal text of the actual argument, converted to a string +constant. Unlike normal parameter replacement, the argument is not +macro-expanded first. This is called @dfn{stringification}. + +There is no way to combine an argument with surrounding text and +stringify it all together. Instead, you can write a series of adjacent +string constants and stringified arguments. The preprocessor will +replace the stringified arguments with string constants. The C +compiler will then combine all the adjacent string constants into one +long string. + +Here is an example of a macro definition that uses stringification: + +@smallexample +@group +#define WARN_IF(EXP) \ +do @{ if (EXP) \ + fprintf (stderr, "Warning: " #EXP "\n"); @} \ +while (0) +WARN_IF (x == 0); + @expansion{} do @{ if (x == 0) + fprintf (stderr, "Warning: " "x == 0" "\n"); @} while (0); +@end group +@end smallexample + +@noindent +The argument for @code{EXP} is substituted once, as-is, into the +@code{if} statement, and once, stringified, into the argument to +@code{fprintf}. If @code{x} were a macro, it would be expanded in the +@code{if} statement, but not in the string. + +The @code{do} and @code{while (0)} are a kludge to make it possible to +write @code{WARN_IF (@var{arg});}, which the resemblance of +@code{WARN_IF} to a function would make C programmers want to do; see +@ref{Swallowing the Semicolon}. + +Stringification in C involves more than putting double-quote characters +around the fragment. The preprocessor backslash-escapes the quotes +surrounding embedded string constants, and all backslashes within string and +character constants, in order to get a valid C string constant with the +proper contents. Thus, stringifying @code{@w{p = "foo\n";}} results in +@t{@w{"p = \"foo\\n\";"}}. However, backslashes that are not inside string +or character constants are not duplicated: @samp{\n} by itself +stringifies to @t{"\n"}. + +All leading and trailing whitespace in text being stringified is +ignored. Any sequence of whitespace in the middle of the text is +converted to a single space in the stringified result. Comments are +replaced by whitespace long before stringification happens, so they +never appear in stringified text. + +There is no way to convert a macro argument into a character constant. + +If you want to stringify the result of expansion of a macro argument, +you have to use two levels of macros. + +@smallexample +#define xstr(s) str(s) +#define str(s) #s +#define foo 4 +str (foo) + @expansion{} "foo" +xstr (foo) + @expansion{} xstr (4) + @expansion{} str (4) + @expansion{} "4" +@end smallexample + +@code{s} is stringified when it is used in @code{str}, so it is not +macro-expanded first. But @code{s} is an ordinary argument to +@code{xstr}, so it is completely macro-expanded before @code{xstr} +itself is expanded (@pxref{Argument Prescan}). Therefore, by the time +@code{str} gets to its argument, it has already been macro-expanded. + +@node Concatenation +@section Concatenation +@cindex concatenation +@cindex token pasting +@cindex token concatenation +@cindex @samp{##} operator + +It is often useful to merge two tokens into one while expanding macros. +This is called @dfn{token pasting} or @dfn{token concatenation}. The +@samp{##} preprocessing operator performs token pasting. When a macro +is expanded, the two tokens on either side of each @samp{##} operator +are combined into a single token, which then replaces the @samp{##} and +the two original tokens in the macro expansion. Usually both will be +identifiers, or one will be an identifier and the other a preprocessing +number. When pasted, they make a longer identifier. This isn't the +only valid case. It is also possible to concatenate two numbers (or a +number and a name, such as @code{1.5} and @code{e3}) into a number. +Also, multi-character operators such as @code{+=} can be formed by +token pasting. + +However, two tokens that don't together form a valid token cannot be +pasted together. For example, you cannot concatenate @code{x} with +@code{+} in either order. If you try, the preprocessor issues a warning +and emits the two tokens. Whether it puts white space between the +tokens is undefined. It is common to find unnecessary uses of @samp{##} +in complex macros. If you get this warning, it is likely that you can +simply remove the @samp{##}. + +Both the tokens combined by @samp{##} could come from the macro body, +but you could just as well write them as one token in the first place. +Token pasting is most useful when one or both of the tokens comes from a +macro argument. If either of the tokens next to an @samp{##} is a +parameter name, it is replaced by its actual argument before @samp{##} +executes. As with stringification, the actual argument is not +macro-expanded first. If the argument is empty, that @samp{##} has no +effect. + +Keep in mind that the C preprocessor converts comments to whitespace +before macros are even considered. Therefore, you cannot create a +comment by concatenating @samp{/} and @samp{*}. You can put as much +whitespace between @samp{##} and its operands as you like, including +comments, and you can put comments in arguments that will be +concatenated. However, it is an error if @samp{##} appears at either +end of a macro body. + +Consider a C program that interprets named commands. There probably +needs to be a table of commands, perhaps an array of structures declared +as follows: + +@smallexample +@group +struct command +@{ + char *name; + void (*function) (void); +@}; +@end group + +@group +struct command commands[] = +@{ + @{ "quit", quit_command @}, + @{ "help", help_command @}, + @dots{} +@}; +@end group +@end smallexample + +It would be cleaner not to have to give each command name twice, once in +the string constant and once in the function name. A macro which takes the +name of a command as an argument can make this unnecessary. The string +constant can be created with stringification, and the function name by +concatenating the argument with @samp{_command}. Here is how it is done: + +@smallexample +#define COMMAND(NAME) @{ #NAME, NAME ## _command @} + +struct command commands[] = +@{ + COMMAND (quit), + COMMAND (help), + @dots{} +@}; +@end smallexample + +@node Variadic Macros +@section Variadic Macros +@cindex variable number of arguments +@cindex macros with variable arguments +@cindex variadic macros + +A macro can be declared to accept a variable number of arguments much as +a function can. The syntax for defining the macro is similar to that of +a function. Here is an example: + +@smallexample +#define eprintf(@dots{}) fprintf (stderr, __VA_ARGS__) +@end smallexample + +This kind of macro is called @dfn{variadic}. When the macro is invoked, +all the tokens in its argument list after the last named argument (this +macro has none), including any commas, become the @dfn{variable +argument}. This sequence of tokens replaces the identifier +@code{@w{__VA_ARGS__}} in the macro body wherever it appears. Thus, we +have this expansion: + +@smallexample +eprintf ("%s:%d: ", input_file, lineno) + @expansion{} fprintf (stderr, "%s:%d: ", input_file, lineno) +@end smallexample + +The variable argument is completely macro-expanded before it is inserted +into the macro expansion, just like an ordinary argument. You may use +the @samp{#} and @samp{##} operators to stringify the variable argument +or to paste its leading or trailing token with another token. (But see +below for an important special case for @samp{##}.) + +If your macro is complicated, you may want a more descriptive name for +the variable argument than @code{@w{__VA_ARGS__}}. CPP permits +this, as an extension. You may write an argument name immediately +before the @samp{@dots{}}; that name is used for the variable argument. +The @code{eprintf} macro above could be written + +@smallexample +#define eprintf(args@dots{}) fprintf (stderr, args) +@end smallexample + +@noindent +using this extension. You cannot use @code{@w{__VA_ARGS__}} and this +extension in the same macro. + +You can have named arguments as well as variable arguments in a variadic +macro. We could define @code{eprintf} like this, instead: + +@smallexample +#define eprintf(format, @dots{}) fprintf (stderr, format, __VA_ARGS__) +@end smallexample + +@noindent +This formulation looks more descriptive, but unfortunately it is less +flexible: you must now supply at least one argument after the format +string. In standard C, you cannot omit the comma separating the named +argument from the variable arguments. Furthermore, if you leave the +variable argument empty, you will get a syntax error, because +there will be an extra comma after the format string. + +@smallexample +eprintf("success!\n", ); + @expansion{} fprintf(stderr, "success!\n", ); +@end smallexample + +GNU CPP has a pair of extensions which deal with this problem. First, +you are allowed to leave the variable argument out entirely: + +@smallexample +eprintf ("success!\n") + @expansion{} fprintf(stderr, "success!\n", ); +@end smallexample + +@noindent +Second, the @samp{##} token paste operator has a special meaning when +placed between a comma and a variable argument. If you write + +@smallexample +#define eprintf(format, @dots{}) fprintf (stderr, format, ##__VA_ARGS__) +@end smallexample + +@noindent +and the variable argument is left out when the @code{eprintf} macro is +used, then the comma before the @samp{##} will be deleted. This does +@emph{not} happen if you pass an empty argument, nor does it happen if +the token preceding @samp{##} is anything other than a comma. + +@smallexample +eprintf ("success!\n") + @expansion{} fprintf(stderr, "success!\n"); +@end smallexample + +@noindent +The above explanation is ambiguous about the case where the only macro +parameter is a variable arguments parameter, as it is meaningless to +try to distinguish whether no argument at all is an empty argument or +a missing argument. In this case the C99 standard is clear that the +comma must remain, however the existing GCC extension used to swallow +the comma. So CPP retains the comma when conforming to a specific C +standard, and drops it otherwise. + +C99 mandates that the only place the identifier @code{@w{__VA_ARGS__}} +can appear is in the replacement list of a variadic macro. It may not +be used as a macro name, macro argument name, or within a different type +of macro. It may also be forbidden in open text; the standard is +ambiguous. We recommend you avoid using it except for its defined +purpose. + +Variadic macros are a new feature in C99. GNU CPP has supported them +for a long time, but only with a named variable argument +(@samp{args@dots{}}, not @samp{@dots{}} and @code{@w{__VA_ARGS__}}). If you are +concerned with portability to previous versions of GCC, you should use +only named variable arguments. On the other hand, if you are concerned +with portability to other conforming implementations of C99, you should +use only @code{@w{__VA_ARGS__}}. + +Previous versions of CPP implemented the comma-deletion extension +much more generally. We have restricted it in this release to minimize +the differences from C99. To get the same effect with both this and +previous versions of GCC, the token preceding the special @samp{##} must +be a comma, and there must be white space between that comma and +whatever comes immediately before it: + +@smallexample +#define eprintf(format, args@dots{}) fprintf (stderr, format , ##args) +@end smallexample + +@noindent +@xref{Differences from previous versions}, for the gory details. + +@node Predefined Macros +@section Predefined Macros + +@cindex predefined macros +Several object-like macros are predefined; you use them without +supplying their definitions. They fall into three classes: standard, +common, and system-specific. + +In C++, there is a fourth category, the named operators. They act like +predefined macros, but you cannot undefine them. + +@menu +* Standard Predefined Macros:: +* Common Predefined Macros:: +* System-specific Predefined Macros:: +* C++ Named Operators:: +@end menu + +@node Standard Predefined Macros +@subsection Standard Predefined Macros +@cindex standard predefined macros. + +The standard predefined macros are specified by the relevant +language standards, so they are available with all compilers that +implement those standards. Older compilers may not provide all of +them. Their names all start with double underscores. + +@table @code +@item __FILE__ +This macro expands to the name of the current input file, in the form of +a C string constant. This is the path by which the preprocessor opened +the file, not the short name specified in @samp{#include} or as the +input file name argument. For example, +@code{"/usr/local/include/myheader.h"} is a possible expansion of this +macro. + +@item __LINE__ +This macro expands to the current input line number, in the form of a +decimal integer constant. While we call it a predefined macro, it's +a pretty strange macro, since its ``definition'' changes with each +new line of source code. +@end table + +@code{__FILE__} and @code{__LINE__} are useful in generating an error +message to report an inconsistency detected by the program; the message +can state the source line at which the inconsistency was detected. For +example, + +@smallexample +fprintf (stderr, "Internal error: " + "negative string length " + "%d at %s, line %d.", + length, __FILE__, __LINE__); +@end smallexample + +An @samp{#include} directive changes the expansions of @code{__FILE__} +and @code{__LINE__} to correspond to the included file. At the end of +that file, when processing resumes on the input file that contained +the @samp{#include} directive, the expansions of @code{__FILE__} and +@code{__LINE__} revert to the values they had before the +@samp{#include} (but @code{__LINE__} is then incremented by one as +processing moves to the line after the @samp{#include}). + +A @samp{#line} directive changes @code{__LINE__}, and may change +@code{__FILE__} as well. @xref{Line Control}. + +C99 introduces @code{__func__}, and GCC has provided @code{__FUNCTION__} +for a long time. Both of these are strings containing the name of the +current function (there are slight semantic differences; see the GCC +manual). Neither of them is a macro; the preprocessor does not know the +name of the current function. They tend to be useful in conjunction +with @code{__FILE__} and @code{__LINE__}, though. + +@table @code + +@item __DATE__ +This macro expands to a string constant that describes the date on which +the preprocessor is being run. The string constant contains eleven +characters and looks like @code{@w{"Feb 12 1996"}}. If the day of the +month is less than 10, it is padded with a space on the left. + +If GCC cannot determine the current date, it will emit a warning message +(once per compilation) and @code{__DATE__} will expand to +@code{@w{"??? ?? ????"}}. + +@item __TIME__ +This macro expands to a string constant that describes the time at +which the preprocessor is being run. The string constant contains +eight characters and looks like @code{"23:59:01"}. + +If GCC cannot determine the current time, it will emit a warning message +(once per compilation) and @code{__TIME__} will expand to +@code{"??:??:??"}. + +@item __STDC__ +In normal operation, this macro expands to the constant 1, to signify +that this compiler conforms to ISO Standard C@. If GNU CPP is used with +a compiler other than GCC, this is not necessarily true; however, the +preprocessor always conforms to the standard unless the +@option{-traditional-cpp} option is used. + +This macro is not defined if the @option{-traditional-cpp} option is used. + +On some hosts, the system compiler uses a different convention, where +@code{__STDC__} is normally 0, but is 1 if the user specifies strict +conformance to the C Standard. CPP follows the host convention when +processing system header files, but when processing user files +@code{__STDC__} is always 1. This has been reported to cause problems; +for instance, some versions of Solaris provide X Windows headers that +expect @code{__STDC__} to be either undefined or 1. @xref{Invocation}. + +@item __STDC_VERSION__ +This macro expands to the C Standard's version number, a long integer +constant of the form @code{@var{yyyy}@var{mm}L} where @var{yyyy} and +@var{mm} are the year and month of the Standard version. This signifies +which version of the C Standard the compiler conforms to. Like +@code{__STDC__}, this is not necessarily accurate for the entire +implementation, unless GNU CPP is being used with GCC@. + +The value @code{199409L} signifies the 1989 C standard as amended in +1994, which is the current default; the value @code{199901L} signifies +the 1999 revision of the C standard. Support for the 1999 revision is +not yet complete. + +This macro is not defined if the @option{-traditional-cpp} option is +used, nor when compiling C++ or Objective-C@. + +@item __STDC_HOSTED__ +This macro is defined, with value 1, if the compiler's target is a +@dfn{hosted environment}. A hosted environment has the complete +facilities of the standard C library available. + +@item __cplusplus +This macro is defined when the C++ compiler is in use. You can use +@code{__cplusplus} to test whether a header is compiled by a C compiler +or a C++ compiler. This macro is similar to @code{__STDC_VERSION__}, in +that it expands to a version number. A fully conforming implementation +of the 1998 C++ standard will define this macro to @code{199711L}. The +GNU C++ compiler is not yet fully conforming, so it uses @code{1} +instead. It is hoped to complete the implementation of standard C++ +in the near future. + +@item __OBJC__ +This macro is defined, with value 1, when the Objective-C compiler is in +use. You can use @code{__OBJC__} to test whether a header is compiled +by a C compiler or a Objective-C compiler. + +@item __ASSEMBLER__ +This macro is defined with value 1 when preprocessing assembly +language. + +@end table + +@node Common Predefined Macros +@subsection Common Predefined Macros +@cindex common predefined macros + +The common predefined macros are GNU C extensions. They are available +with the same meanings regardless of the machine or operating system on +which you are using GNU C@. Their names all start with double +underscores. + +@table @code + +@item __GNUC__ +@itemx __GNUC_MINOR__ +@itemx __GNUC_PATCHLEVEL__ +These macros are defined by all GNU compilers that use the C +preprocessor: C, C++, and Objective-C@. Their values are the major +version, minor version, and patch level of the compiler, as integer +constants. For example, GCC 3.2.1 will define @code{__GNUC__} to 3, +@code{__GNUC_MINOR__} to 2, and @code{__GNUC_PATCHLEVEL__} to 1. These +macros are also defined if you invoke the preprocessor directly. + +@code{__GNUC_PATCHLEVEL__} is new to GCC 3.0; it is also present in the +widely-used development snapshots leading up to 3.0 (which identify +themselves as GCC 2.96 or 2.97, depending on which snapshot you have). + +If all you need to know is whether or not your program is being compiled +by GCC, or a non-GCC compiler that claims to accept the GNU C dialects, +you can simply test @code{__GNUC__}. If you need to write code +which depends on a specific version, you must be more careful. Each +time the minor version is increased, the patch level is reset to zero; +each time the major version is increased (which happens rarely), the +minor version and patch level are reset. If you wish to use the +predefined macros directly in the conditional, you will need to write it +like this: + +@smallexample +/* @r{Test for GCC > 3.2.0} */ +#if __GNUC__ > 3 || \ + (__GNUC__ == 3 && (__GNUC_MINOR__ > 2 || \ + (__GNUC_MINOR__ == 2 && \ + __GNUC_PATCHLEVEL__ > 0)) +@end smallexample + +@noindent +Another approach is to use the predefined macros to +calculate a single number, then compare that against a threshold: + +@smallexample +#define GCC_VERSION (__GNUC__ * 10000 \ + + __GNUC_MINOR__ * 100 \ + + __GNUC_PATCHLEVEL__) +@dots{} +/* @r{Test for GCC > 3.2.0} */ +#if GCC_VERSION > 30200 +@end smallexample + +@noindent +Many people find this form easier to understand. + +@item __GNUG__ +The GNU C++ compiler defines this. Testing it is equivalent to +testing @code{@w{(__GNUC__ && __cplusplus)}}. + +@item __STRICT_ANSI__ +GCC defines this macro if and only if the @option{-ansi} switch, or a +@option{-std} switch specifying strict conformance to some version of ISO C, +was specified when GCC was invoked. It is defined to @samp{1}. +This macro exists primarily to direct GNU libc's header files to +restrict their definitions to the minimal set found in the 1989 C +standard. + +@item __BASE_FILE__ +This macro expands to the name of the main input file, in the form +of a C string constant. This is the source file that was specified +on the command line of the preprocessor or C compiler. + +@item __INCLUDE_LEVEL__ +This macro expands to a decimal integer constant that represents the +depth of nesting in include files. The value of this macro is +incremented on every @samp{#include} directive and decremented at the +end of every included file. It starts out at 0, it's value within the +base file specified on the command line. + +@item __ELF__ +This macro is defined if the target uses the ELF object format. + +@item __VERSION__ +This macro expands to a string constant which describes the version of +the compiler in use. You should not rely on its contents having any +particular form, but it can be counted on to contain at least the +release number. + +@c APPLE LOCAL begin radar 4224728 +@item __PIC__ +This macro is defined when gcc is generating pic code for darwin. +@c APPLE LOCAL end radar 4224728 + +@item __OPTIMIZE__ +@itemx __OPTIMIZE_SIZE__ +@itemx __NO_INLINE__ +These macros describe the compilation mode. @code{__OPTIMIZE__} is +defined in all optimizing compilations. @code{__OPTIMIZE_SIZE__} is +defined if the compiler is optimizing for size, not speed. +@code{__NO_INLINE__} is defined if no functions will be inlined into +their callers (when not optimizing, or when inlining has been +specifically disabled by @option{-fno-inline}). + +These macros cause certain GNU header files to provide optimized +definitions, using macros or inline functions, of system library +functions. You should not use these macros in any way unless you make +sure that programs will execute with the same effect whether or not they +are defined. If they are defined, their value is 1. + +@item __GNUC_GNU_INLINE__ +GCC defines this macro if functions declared @code{inline} will be +handled in GCC's traditional gnu89 mode. In this mode an @code{extern +inline} function will never be compiled as a standalone function, and +an @code{inline} function which is neither @code{extern} nor +@code{static} will always be compiled as a standalone function. + +@item __GNUC_STDC_INLINE__ +GCC defines this macro if functions declared @code{inline} will be +handled according to the ISO C99 standard. In this mode an +@code{extern inline} function will always be compiled as a standalone +externally visible function, and an @code{inline} function which is +neither @code{extern} nor @code{static} will never be compiled as a +standalone function. + +If this macro is defined, GCC supports the @code{gnu_inline} function +attribute as a way to always get the gnu89 behaviour. Support for +this and @code{__GNUC_GNU_INLINE__} was added in GCC 4.1.3. If +neither macro is defined, an older version of GCC is being used: +@code{inline} functions will be compiled in gnu89 mode, and the +@code{gnu_inline} function attribute will not be recognized. + +@item __CHAR_UNSIGNED__ +GCC defines this macro if and only if the data type @code{char} is +unsigned on the target machine. It exists to cause the standard header +file @file{limits.h} to work correctly. You should not use this macro +yourself; instead, refer to the standard macros defined in @file{limits.h}. + +@item __WCHAR_UNSIGNED__ +Like @code{__CHAR_UNSIGNED__}, this macro is defined if and only if the +data type @code{wchar_t} is unsigned and the front-end is in C++ mode. + +@item __REGISTER_PREFIX__ +This macro expands to a single token (not a string constant) which is +the prefix applied to CPU register names in assembly language for this +target. You can use it to write assembly that is usable in multiple +environments. For example, in the @code{m68k-aout} environment it +expands to nothing, but in the @code{m68k-coff} environment it expands +to a single @samp{%}. + +@item __USER_LABEL_PREFIX__ +This macro expands to a single token which is the prefix applied to +user labels (symbols visible to C code) in assembly. For example, in +the @code{m68k-aout} environment it expands to an @samp{_}, but in the +@code{m68k-coff} environment it expands to nothing. + +This macro will have the correct definition even if +@option{-f(no-)underscores} is in use, but it will not be correct if +target-specific options that adjust this prefix are used (e.g.@: the +OSF/rose @option{-mno-underscores} option). + +@item __SIZE_TYPE__ +@itemx __PTRDIFF_TYPE__ +@itemx __WCHAR_TYPE__ +@itemx __WINT_TYPE__ +@itemx __INTMAX_TYPE__ +@itemx __UINTMAX_TYPE__ +These macros are defined to the correct underlying types for the +@code{size_t}, @code{ptrdiff_t}, @code{wchar_t}, @code{wint_t}, +@code{intmax_t}, and @code{uintmax_t} +typedefs, respectively. They exist to make the standard header files +@file{stddef.h} and @file{wchar.h} work correctly. You should not use +these macros directly; instead, include the appropriate headers and use +the typedefs. + +@item __CHAR_BIT__ +Defined to the number of bits used in the representation of the +@code{char} data type. It exists to make the standard header given +numerical limits work correctly. You should not use +this macro directly; instead, include the appropriate headers. + +@item __SCHAR_MAX__ +@itemx __WCHAR_MAX__ +@itemx __SHRT_MAX__ +@itemx __INT_MAX__ +@itemx __LONG_MAX__ +@itemx __LONG_LONG_MAX__ +@itemx __INTMAX_MAX__ +Defined to the maximum value of the @code{signed char}, @code{wchar_t}, +@code{signed short}, +@code{signed int}, @code{signed long}, @code{signed long long}, and +@code{intmax_t} types +respectively. They exist to make the standard header given numerical limits +work correctly. You should not use these macros directly; instead, include +the appropriate headers. + +@item __DEPRECATED +This macro is defined, with value 1, when compiling a C++ source file +with warnings about deprecated constructs enabled. These warnings are +enabled by default, but can be disabled with @option{-Wno-deprecated}. + +@item __EXCEPTIONS +This macro is defined, with value 1, when compiling a C++ source file +with exceptions enabled. If @option{-fno-exceptions} was used when +compiling the file, then this macro will not be defined. + +@item __USING_SJLJ_EXCEPTIONS__ +This macro is defined, with value 1, if the compiler uses the old +mechanism based on @code{setjmp} and @code{longjmp} for exception +handling. + +@item __GXX_WEAK__ +This macro is defined when compiling a C++ source file. It has the +value 1 if the compiler will use weak symbols, COMDAT sections, or +other similar techniques to collapse symbols with ``vague linkage'' +that are defined in multiple translation units. If the compiler will +not collapse such symbols, this macro is defined with value 0. In +general, user code should not need to make use of this macro; the +purpose of this macro is to ease implementation of the C++ runtime +library provided with G++. + +@item __NEXT_RUNTIME__ +This macro is defined, with value 1, if (and only if) the NeXT runtime +(as in @option{-fnext-runtime}) is in use for Objective-C@. If the GNU +runtime is used, this macro is not defined, so that you can use this +macro to determine which runtime (NeXT or GNU) is being used. + +@item __LP64__ +@itemx _LP64 +These macros are defined, with value 1, if (and only if) the compilation +is for a target where @code{long int} and pointer both use 64-bits and +@code{int} uses 32-bit. + +@item __SSP__ +This macro is defined, with value 1, when @option{-fstack-protector} is in +use. + +@item __SSP_ALL__ +This macro is defined, with value 2, when @option{-fstack-protector-all} is +in use. + +@item __TIMESTAMP__ +This macro expands to a string constant that describes the date and time +of the last modification of the current source file. The string constant +contains abbreviated day of the week, month, day of the month, time in +hh:mm:ss form, year and looks like @code{@w{"Sun Sep 16 01:03:52 1973"}}. +If the day of the month is less than 10, it is padded with a space on the left. + +If GCC cannot determine the current date, it will emit a warning message +(once per compilation) and @code{__TIMESTAMP__} will expand to +@code{@w{"??? ??? ?? ??:??:?? ????"}}. + +@end table + +@node System-specific Predefined Macros +@subsection System-specific Predefined Macros + +@cindex system-specific predefined macros +@cindex predefined macros, system-specific +@cindex reserved namespace + +The C preprocessor normally predefines several macros that indicate what +type of system and machine is in use. They are obviously different on +each target supported by GCC@. This manual, being for all systems and +machines, cannot tell you what their names are, but you can use +@command{cpp -dM} to see them all. @xref{Invocation}. All system-specific +predefined macros expand to the constant 1, so you can test them with +either @samp{#ifdef} or @samp{#if}. + +The C standard requires that all system-specific macros be part of the +@dfn{reserved namespace}. All names which begin with two underscores, +or an underscore and a capital letter, are reserved for the compiler and +library to use as they wish. However, historically system-specific +macros have had names with no special prefix; for instance, it is common +to find @code{unix} defined on Unix systems. For all such macros, GCC +provides a parallel macro with two underscores added at the beginning +and the end. If @code{unix} is defined, @code{__unix__} will be defined +too. There will never be more than two underscores; the parallel of +@code{_mips} is @code{__mips__}. + +When the @option{-ansi} option, or any @option{-std} option that +requests strict conformance, is given to the compiler, all the +system-specific predefined macros outside the reserved namespace are +suppressed. The parallel macros, inside the reserved namespace, remain +defined. + +We are slowly phasing out all predefined macros which are outside the +reserved namespace. You should never use them in new programs, and we +encourage you to correct older code to use the parallel macros whenever +you find it. We don't recommend you use the system-specific macros that +are in the reserved namespace, either. It is better in the long run to +check specifically for features you need, using a tool such as +@command{autoconf}. + +@node C++ Named Operators +@subsection C++ Named Operators +@cindex named operators +@cindex C++ named operators +@cindex iso646.h + +In C++, there are eleven keywords which are simply alternate spellings +of operators normally written with punctuation. These keywords are +treated as such even in the preprocessor. They function as operators in +@samp{#if}, and they cannot be defined as macros or poisoned. In C, you +can request that those keywords take their C++ meaning by including +@file{iso646.h}. That header defines each one as a normal object-like +macro expanding to the appropriate punctuator. + +These are the named operators and their corresponding punctuators: + +@multitable {Named Operator} {Punctuator} +@item Named Operator @tab Punctuator +@item @code{and} @tab @code{&&} +@item @code{and_eq} @tab @code{&=} +@item @code{bitand} @tab @code{&} +@item @code{bitor} @tab @code{|} +@item @code{compl} @tab @code{~} +@item @code{not} @tab @code{!} +@item @code{not_eq} @tab @code{!=} +@item @code{or} @tab @code{||} +@item @code{or_eq} @tab @code{|=} +@item @code{xor} @tab @code{^} +@item @code{xor_eq} @tab @code{^=} +@end multitable + +@node Undefining and Redefining Macros +@section Undefining and Redefining Macros +@cindex undefining macros +@cindex redefining macros +@findex #undef + +If a macro ceases to be useful, it may be @dfn{undefined} with the +@samp{#undef} directive. @samp{#undef} takes a single argument, the +name of the macro to undefine. You use the bare macro name, even if the +macro is function-like. It is an error if anything appears on the line +after the macro name. @samp{#undef} has no effect if the name is not a +macro. + +@smallexample +#define FOO 4 +x = FOO; @expansion{} x = 4; +#undef FOO +x = FOO; @expansion{} x = FOO; +@end smallexample + +Once a macro has been undefined, that identifier may be @dfn{redefined} +as a macro by a subsequent @samp{#define} directive. The new definition +need not have any resemblance to the old definition. + +However, if an identifier which is currently a macro is redefined, then +the new definition must be @dfn{effectively the same} as the old one. +Two macro definitions are effectively the same if: +@itemize @bullet +@item Both are the same type of macro (object- or function-like). +@item All the tokens of the replacement list are the same. +@item If there are any parameters, they are the same. +@item Whitespace appears in the same places in both. It need not be +exactly the same amount of whitespace, though. Remember that comments +count as whitespace. +@end itemize + +@noindent +These definitions are effectively the same: +@smallexample +#define FOUR (2 + 2) +#define FOUR (2 + 2) +#define FOUR (2 /* @r{two} */ + 2) +@end smallexample +@noindent +but these are not: +@smallexample +#define FOUR (2 + 2) +#define FOUR ( 2+2 ) +#define FOUR (2 * 2) +#define FOUR(score,and,seven,years,ago) (2 + 2) +@end smallexample + +If a macro is redefined with a definition that is not effectively the +same as the old one, the preprocessor issues a warning and changes the +macro to use the new definition. If the new definition is effectively +the same, the redefinition is silently ignored. This allows, for +instance, two different headers to define a common macro. The +preprocessor will only complain if the definitions do not match. + +@node Directives Within Macro Arguments +@section Directives Within Macro Arguments +@cindex macro arguments and directives + +Occasionally it is convenient to use preprocessor directives within +the arguments of a macro. The C and C++ standards declare that +behavior in these cases is undefined. + +Versions of CPP prior to 3.2 would reject such constructs with an +error message. This was the only syntactic difference between normal +functions and function-like macros, so it seemed attractive to remove +this limitation, and people would often be surprised that they could +not use macros in this way. Moreover, sometimes people would use +conditional compilation in the argument list to a normal library +function like @samp{printf}, only to find that after a library upgrade +@samp{printf} had changed to be a function-like macro, and their code +would no longer compile. So from version 3.2 we changed CPP to +successfully process arbitrary directives within macro arguments in +exactly the same way as it would have processed the directive were the +function-like macro invocation not present. + +If, within a macro invocation, that macro is redefined, then the new +definition takes effect in time for argument pre-expansion, but the +original definition is still used for argument replacement. Here is a +pathological example: + +@smallexample +#define f(x) x x +f (1 +#undef f +#define f 2 +f) +@end smallexample + +@noindent +which expands to + +@smallexample +1 2 1 2 +@end smallexample + +@noindent +with the semantics described above. + +@node Macro Pitfalls +@section Macro Pitfalls +@cindex problems with macros +@cindex pitfalls of macros + +In this section we describe some special rules that apply to macros and +macro expansion, and point out certain cases in which the rules have +counter-intuitive consequences that you must watch out for. + +@menu +* Misnesting:: +* Operator Precedence Problems:: +* Swallowing the Semicolon:: +* Duplication of Side Effects:: +* Self-Referential Macros:: +* Argument Prescan:: +* Newlines in Arguments:: +@end menu + +@node Misnesting +@subsection Misnesting + +When a macro is called with arguments, the arguments are substituted +into the macro body and the result is checked, together with the rest of +the input file, for more macro calls. It is possible to piece together +a macro call coming partially from the macro body and partially from the +arguments. For example, + +@smallexample +#define twice(x) (2*(x)) +#define call_with_1(x) x(1) +call_with_1 (twice) + @expansion{} twice(1) + @expansion{} (2*(1)) +@end smallexample + +Macro definitions do not have to have balanced parentheses. By writing +an unbalanced open parenthesis in a macro body, it is possible to create +a macro call that begins inside the macro body but ends outside of it. +For example, + +@smallexample +#define strange(file) fprintf (file, "%s %d", +@dots{} +strange(stderr) p, 35) + @expansion{} fprintf (stderr, "%s %d", p, 35) +@end smallexample + +The ability to piece together a macro call can be useful, but the use of +unbalanced open parentheses in a macro body is just confusing, and +should be avoided. + +@node Operator Precedence Problems +@subsection Operator Precedence Problems +@cindex parentheses in macro bodies + +You may have noticed that in most of the macro definition examples shown +above, each occurrence of a macro argument name had parentheses around +it. In addition, another pair of parentheses usually surround the +entire macro definition. Here is why it is best to write macros that +way. + +Suppose you define a macro as follows, + +@smallexample +#define ceil_div(x, y) (x + y - 1) / y +@end smallexample + +@noindent +whose purpose is to divide, rounding up. (One use for this operation is +to compute how many @code{int} objects are needed to hold a certain +number of @code{char} objects.) Then suppose it is used as follows: + +@smallexample +a = ceil_div (b & c, sizeof (int)); + @expansion{} a = (b & c + sizeof (int) - 1) / sizeof (int); +@end smallexample + +@noindent +This does not do what is intended. The operator-precedence rules of +C make it equivalent to this: + +@smallexample +a = (b & (c + sizeof (int) - 1)) / sizeof (int); +@end smallexample + +@noindent +What we want is this: + +@smallexample +a = ((b & c) + sizeof (int) - 1)) / sizeof (int); +@end smallexample + +@noindent +Defining the macro as + +@smallexample +#define ceil_div(x, y) ((x) + (y) - 1) / (y) +@end smallexample + +@noindent +provides the desired result. + +Unintended grouping can result in another way. Consider @code{sizeof +ceil_div(1, 2)}. That has the appearance of a C expression that would +compute the size of the type of @code{ceil_div (1, 2)}, but in fact it +means something very different. Here is what it expands to: + +@smallexample +sizeof ((1) + (2) - 1) / (2) +@end smallexample + +@noindent +This would take the size of an integer and divide it by two. The +precedence rules have put the division outside the @code{sizeof} when it +was intended to be inside. + +Parentheses around the entire macro definition prevent such problems. +Here, then, is the recommended way to define @code{ceil_div}: + +@smallexample +#define ceil_div(x, y) (((x) + (y) - 1) / (y)) +@end smallexample + +@node Swallowing the Semicolon +@subsection Swallowing the Semicolon +@cindex semicolons (after macro calls) + +Often it is desirable to define a macro that expands into a compound +statement. Consider, for example, the following macro, that advances a +pointer (the argument @code{p} says where to find it) across whitespace +characters: + +@smallexample +#define SKIP_SPACES(p, limit) \ +@{ char *lim = (limit); \ + while (p < lim) @{ \ + if (*p++ != ' ') @{ \ + p--; break; @}@}@} +@end smallexample + +@noindent +Here backslash-newline is used to split the macro definition, which must +be a single logical line, so that it resembles the way such code would +be laid out if not part of a macro definition. + +A call to this macro might be @code{SKIP_SPACES (p, lim)}. Strictly +speaking, the call expands to a compound statement, which is a complete +statement with no need for a semicolon to end it. However, since it +looks like a function call, it minimizes confusion if you can use it +like a function call, writing a semicolon afterward, as in +@code{SKIP_SPACES (p, lim);} + +This can cause trouble before @code{else} statements, because the +semicolon is actually a null statement. Suppose you write + +@smallexample +if (*p != 0) + SKIP_SPACES (p, lim); +else @dots{} +@end smallexample + +@noindent +The presence of two statements---the compound statement and a null +statement---in between the @code{if} condition and the @code{else} +makes invalid C code. + +The definition of the macro @code{SKIP_SPACES} can be altered to solve +this problem, using a @code{do @dots{} while} statement. Here is how: + +@smallexample +#define SKIP_SPACES(p, limit) \ +do @{ char *lim = (limit); \ + while (p < lim) @{ \ + if (*p++ != ' ') @{ \ + p--; break; @}@}@} \ +while (0) +@end smallexample + +Now @code{SKIP_SPACES (p, lim);} expands into + +@smallexample +do @{@dots{}@} while (0); +@end smallexample + +@noindent +which is one statement. The loop executes exactly once; most compilers +generate no extra code for it. + +@node Duplication of Side Effects +@subsection Duplication of Side Effects + +@cindex side effects (in macro arguments) +@cindex unsafe macros +Many C programs define a macro @code{min}, for ``minimum'', like this: + +@smallexample +#define min(X, Y) ((X) < (Y) ? (X) : (Y)) +@end smallexample + +When you use this macro with an argument containing a side effect, +as shown here, + +@smallexample +next = min (x + y, foo (z)); +@end smallexample + +@noindent +it expands as follows: + +@smallexample +next = ((x + y) < (foo (z)) ? (x + y) : (foo (z))); +@end smallexample + +@noindent +where @code{x + y} has been substituted for @code{X} and @code{foo (z)} +for @code{Y}. + +The function @code{foo} is used only once in the statement as it appears +in the program, but the expression @code{foo (z)} has been substituted +twice into the macro expansion. As a result, @code{foo} might be called +two times when the statement is executed. If it has side effects or if +it takes a long time to compute, the results might not be what you +intended. We say that @code{min} is an @dfn{unsafe} macro. + +The best solution to this problem is to define @code{min} in a way that +computes the value of @code{foo (z)} only once. The C language offers +no standard way to do this, but it can be done with GNU extensions as +follows: + +@smallexample +#define min(X, Y) \ +(@{ typeof (X) x_ = (X); \ + typeof (Y) y_ = (Y); \ + (x_ < y_) ? x_ : y_; @}) +@end smallexample + +The @samp{(@{ @dots{} @})} notation produces a compound statement that +acts as an expression. Its value is the value of its last statement. +This permits us to define local variables and assign each argument to +one. The local variables have underscores after their names to reduce +the risk of conflict with an identifier of wider scope (it is impossible +to avoid this entirely). Now each argument is evaluated exactly once. + +If you do not wish to use GNU C extensions, the only solution is to be +careful when @emph{using} the macro @code{min}. For example, you can +calculate the value of @code{foo (z)}, save it in a variable, and use +that variable in @code{min}: + +@smallexample +@group +#define min(X, Y) ((X) < (Y) ? (X) : (Y)) +@dots{} +@{ + int tem = foo (z); + next = min (x + y, tem); +@} +@end group +@end smallexample + +@noindent +(where we assume that @code{foo} returns type @code{int}). + +@node Self-Referential Macros +@subsection Self-Referential Macros +@cindex self-reference + +A @dfn{self-referential} macro is one whose name appears in its +definition. Recall that all macro definitions are rescanned for more +macros to replace. If the self-reference were considered a use of the +macro, it would produce an infinitely large expansion. To prevent this, +the self-reference is not considered a macro call. It is passed into +the preprocessor output unchanged. Consider an example: + +@smallexample +#define foo (4 + foo) +@end smallexample + +@noindent +where @code{foo} is also a variable in your program. + +Following the ordinary rules, each reference to @code{foo} will expand +into @code{(4 + foo)}; then this will be rescanned and will expand into +@code{(4 + (4 + foo))}; and so on until the computer runs out of memory. + +The self-reference rule cuts this process short after one step, at +@code{(4 + foo)}. Therefore, this macro definition has the possibly +useful effect of causing the program to add 4 to the value of @code{foo} +wherever @code{foo} is referred to. + +In most cases, it is a bad idea to take advantage of this feature. A +person reading the program who sees that @code{foo} is a variable will +not expect that it is a macro as well. The reader will come across the +identifier @code{foo} in the program and think its value should be that +of the variable @code{foo}, whereas in fact the value is four greater. + +One common, useful use of self-reference is to create a macro which +expands to itself. If you write + +@smallexample +#define EPERM EPERM +@end smallexample + +@noindent +then the macro @code{EPERM} expands to @code{EPERM}. Effectively, it is +left alone by the preprocessor whenever it's used in running text. You +can tell that it's a macro with @samp{#ifdef}. You might do this if you +want to define numeric constants with an @code{enum}, but have +@samp{#ifdef} be true for each constant. + +If a macro @code{x} expands to use a macro @code{y}, and the expansion of +@code{y} refers to the macro @code{x}, that is an @dfn{indirect +self-reference} of @code{x}. @code{x} is not expanded in this case +either. Thus, if we have + +@smallexample +#define x (4 + y) +#define y (2 * x) +@end smallexample + +@noindent +then @code{x} and @code{y} expand as follows: + +@smallexample +@group +x @expansion{} (4 + y) + @expansion{} (4 + (2 * x)) + +y @expansion{} (2 * x) + @expansion{} (2 * (4 + y)) +@end group +@end smallexample + +@noindent +Each macro is expanded when it appears in the definition of the other +macro, but not when it indirectly appears in its own definition. + +@node Argument Prescan +@subsection Argument Prescan +@cindex expansion of arguments +@cindex macro argument expansion +@cindex prescan of macro arguments + +Macro arguments are completely macro-expanded before they are +substituted into a macro body, unless they are stringified or pasted +with other tokens. After substitution, the entire macro body, including +the substituted arguments, is scanned again for macros to be expanded. +The result is that the arguments are scanned @emph{twice} to expand +macro calls in them. + +Most of the time, this has no effect. If the argument contained any +macro calls, they are expanded during the first scan. The result +therefore contains no macro calls, so the second scan does not change +it. If the argument were substituted as given, with no prescan, the +single remaining scan would find the same macro calls and produce the +same results. + +You might expect the double scan to change the results when a +self-referential macro is used in an argument of another macro +(@pxref{Self-Referential Macros}): the self-referential macro would be +expanded once in the first scan, and a second time in the second scan. +However, this is not what happens. The self-references that do not +expand in the first scan are marked so that they will not expand in the +second scan either. + +You might wonder, ``Why mention the prescan, if it makes no difference? +And why not skip it and make the preprocessor faster?'' The answer is +that the prescan does make a difference in three special cases: + +@itemize @bullet +@item +Nested calls to a macro. + +We say that @dfn{nested} calls to a macro occur when a macro's argument +contains a call to that very macro. For example, if @code{f} is a macro +that expects one argument, @code{f (f (1))} is a nested pair of calls to +@code{f}. The desired expansion is made by expanding @code{f (1)} and +substituting that into the definition of @code{f}. The prescan causes +the expected result to happen. Without the prescan, @code{f (1)} itself +would be substituted as an argument, and the inner use of @code{f} would +appear during the main scan as an indirect self-reference and would not +be expanded. + +@item +Macros that call other macros that stringify or concatenate. + +If an argument is stringified or concatenated, the prescan does not +occur. If you @emph{want} to expand a macro, then stringify or +concatenate its expansion, you can do that by causing one macro to call +another macro that does the stringification or concatenation. For +instance, if you have + +@smallexample +#define AFTERX(x) X_ ## x +#define XAFTERX(x) AFTERX(x) +#define TABLESIZE 1024 +#define BUFSIZE TABLESIZE +@end smallexample + +then @code{AFTERX(BUFSIZE)} expands to @code{X_BUFSIZE}, and +@code{XAFTERX(BUFSIZE)} expands to @code{X_1024}. (Not to +@code{X_TABLESIZE}. Prescan always does a complete expansion.) + +@item +Macros used in arguments, whose expansions contain unshielded commas. + +This can cause a macro expanded on the second scan to be called with the +wrong number of arguments. Here is an example: + +@smallexample +#define foo a,b +#define bar(x) lose(x) +#define lose(x) (1 + (x)) +@end smallexample + +We would like @code{bar(foo)} to turn into @code{(1 + (foo))}, which +would then turn into @code{(1 + (a,b))}. Instead, @code{bar(foo)} +expands into @code{lose(a,b)}, and you get an error because @code{lose} +requires a single argument. In this case, the problem is easily solved +by the same parentheses that ought to be used to prevent misnesting of +arithmetic operations: + +@smallexample +#define foo (a,b) +@exdent or +#define bar(x) lose((x)) +@end smallexample + +The extra pair of parentheses prevents the comma in @code{foo}'s +definition from being interpreted as an argument separator. + +@end itemize + +@node Newlines in Arguments +@subsection Newlines in Arguments +@cindex newlines in macro arguments + +The invocation of a function-like macro can extend over many logical +lines. However, in the present implementation, the entire expansion +comes out on one line. Thus line numbers emitted by the compiler or +debugger refer to the line the invocation started on, which might be +different to the line containing the argument causing the problem. + +Here is an example illustrating this: + +@smallexample +#define ignore_second_arg(a,b,c) a; c + +ignore_second_arg (foo (), + ignored (), + syntax error); +@end smallexample + +@noindent +The syntax error triggered by the tokens @code{syntax error} results in +an error message citing line three---the line of ignore_second_arg--- +even though the problematic code comes from line five. + +We consider this a bug, and intend to fix it in the near future. + +@node Conditionals +@chapter Conditionals +@cindex conditionals + +A @dfn{conditional} is a directive that instructs the preprocessor to +select whether or not to include a chunk of code in the final token +stream passed to the compiler. Preprocessor conditionals can test +arithmetic expressions, or whether a name is defined as a macro, or both +simultaneously using the special @code{defined} operator. + +A conditional in the C preprocessor resembles in some ways an @code{if} +statement in C, but it is important to understand the difference between +them. The condition in an @code{if} statement is tested during the +execution of your program. Its purpose is to allow your program to +behave differently from run to run, depending on the data it is +operating on. The condition in a preprocessing conditional directive is +tested when your program is compiled. Its purpose is to allow different +code to be included in the program depending on the situation at the +time of compilation. + +However, the distinction is becoming less clear. Modern compilers often +do test @code{if} statements when a program is compiled, if their +conditions are known not to vary at run time, and eliminate code which +can never be executed. If you can count on your compiler to do this, +you may find that your program is more readable if you use @code{if} +statements with constant conditions (perhaps determined by macros). Of +course, you can only use this to exclude code, not type definitions or +other preprocessing directives, and you can only do it if the code +remains syntactically valid when it is not to be used. + +GCC version 3 eliminates this kind of never-executed code even when +not optimizing. Older versions did it only when optimizing. + +@menu +* Conditional Uses:: +* Conditional Syntax:: +* Deleted Code:: +@end menu + +@node Conditional Uses +@section Conditional Uses + +There are three general reasons to use a conditional. + +@itemize @bullet +@item +A program may need to use different code depending on the machine or +operating system it is to run on. In some cases the code for one +operating system may be erroneous on another operating system; for +example, it might refer to data types or constants that do not exist on +the other system. When this happens, it is not enough to avoid +executing the invalid code. Its mere presence will cause the compiler +to reject the program. With a preprocessing conditional, the offending +code can be effectively excised from the program when it is not valid. + +@item +You may want to be able to compile the same source file into two +different programs. One version might make frequent time-consuming +consistency checks on its intermediate data, or print the values of +those data for debugging, and the other not. + +@item +A conditional whose condition is always false is one way to exclude code +from the program but keep it as a sort of comment for future reference. +@end itemize + +Simple programs that do not need system-specific logic or complex +debugging hooks generally will not need to use preprocessing +conditionals. + +@node Conditional Syntax +@section Conditional Syntax + +@findex #if +A conditional in the C preprocessor begins with a @dfn{conditional +directive}: @samp{#if}, @samp{#ifdef} or @samp{#ifndef}. + +@menu +* Ifdef:: +* If:: +* Defined:: +* Else:: +* Elif:: +@end menu + +@node Ifdef +@subsection Ifdef +@findex #ifdef +@findex #endif + +The simplest sort of conditional is + +@smallexample +@group +#ifdef @var{MACRO} + +@var{controlled text} + +#endif /* @var{MACRO} */ +@end group +@end smallexample + +@cindex conditional group +This block is called a @dfn{conditional group}. @var{controlled text} +will be included in the output of the preprocessor if and only if +@var{MACRO} is defined. We say that the conditional @dfn{succeeds} if +@var{MACRO} is defined, @dfn{fails} if it is not. + +The @var{controlled text} inside of a conditional can include +preprocessing directives. They are executed only if the conditional +succeeds. You can nest conditional groups inside other conditional +groups, but they must be completely nested. In other words, +@samp{#endif} always matches the nearest @samp{#ifdef} (or +@samp{#ifndef}, or @samp{#if}). Also, you cannot start a conditional +group in one file and end it in another. + +Even if a conditional fails, the @var{controlled text} inside it is +still run through initial transformations and tokenization. Therefore, +it must all be lexically valid C@. Normally the only way this matters is +that all comments and string literals inside a failing conditional group +must still be properly ended. + +The comment following the @samp{#endif} is not required, but it is a +good practice if there is a lot of @var{controlled text}, because it +helps people match the @samp{#endif} to the corresponding @samp{#ifdef}. +Older programs sometimes put @var{MACRO} directly after the +@samp{#endif} without enclosing it in a comment. This is invalid code +according to the C standard. CPP accepts it with a warning. It +never affects which @samp{#ifndef} the @samp{#endif} matches. + +@findex #ifndef +Sometimes you wish to use some code if a macro is @emph{not} defined. +You can do this by writing @samp{#ifndef} instead of @samp{#ifdef}. +One common use of @samp{#ifndef} is to include code only the first +time a header file is included. @xref{Once-Only Headers}. + +Macro definitions can vary between compilations for several reasons. +Here are some samples. + +@itemize @bullet +@item +Some macros are predefined on each kind of machine +(@pxref{System-specific Predefined Macros}). This allows you to provide +code specially tuned for a particular machine. + +@item +System header files define more macros, associated with the features +they implement. You can test these macros with conditionals to avoid +using a system feature on a machine where it is not implemented. + +@item +Macros can be defined or undefined with the @option{-D} and @option{-U} +command line options when you compile the program. You can arrange to +compile the same source file into two different programs by choosing a +macro name to specify which program you want, writing conditionals to +test whether or how this macro is defined, and then controlling the +state of the macro with command line options, perhaps set in the +Makefile. @xref{Invocation}. + +@item +Your program might have a special header file (often called +@file{config.h}) that is adjusted when the program is compiled. It can +define or not define macros depending on the features of the system and +the desired capabilities of the program. The adjustment can be +automated by a tool such as @command{autoconf}, or done by hand. +@end itemize + +@node If +@subsection If + +The @samp{#if} directive allows you to test the value of an arithmetic +expression, rather than the mere existence of one macro. Its syntax is + +@smallexample +@group +#if @var{expression} + +@var{controlled text} + +#endif /* @var{expression} */ +@end group +@end smallexample + +@var{expression} is a C expression of integer type, subject to stringent +restrictions. It may contain + +@itemize @bullet +@item +Integer constants. + +@item +Character constants, which are interpreted as they would be in normal +code. + +@item +Arithmetic operators for addition, subtraction, multiplication, +division, bitwise operations, shifts, comparisons, and logical +operations (@code{&&} and @code{||}). The latter two obey the usual +short-circuiting rules of standard C@. + +@item +Macros. All macros in the expression are expanded before actual +computation of the expression's value begins. + +@item +Uses of the @code{defined} operator, which lets you check whether macros +are defined in the middle of an @samp{#if}. + +@item +Identifiers that are not macros, which are all considered to be the +number zero. This allows you to write @code{@w{#if MACRO}} instead of +@code{@w{#ifdef MACRO}}, if you know that MACRO, when defined, will +always have a nonzero value. Function-like macros used without their +function call parentheses are also treated as zero. + +In some contexts this shortcut is undesirable. The @option{-Wundef} +option causes GCC to warn whenever it encounters an identifier which is +not a macro in an @samp{#if}. +@end itemize + +The preprocessor does not know anything about types in the language. +Therefore, @code{sizeof} operators are not recognized in @samp{#if}, and +neither are @code{enum} constants. They will be taken as identifiers +which are not macros, and replaced by zero. In the case of +@code{sizeof}, this is likely to cause the expression to be invalid. + +The preprocessor calculates the value of @var{expression}. It carries +out all calculations in the widest integer type known to the compiler; +on most machines supported by GCC this is 64 bits. This is not the same +rule as the compiler uses to calculate the value of a constant +expression, and may give different results in some cases. If the value +comes out to be nonzero, the @samp{#if} succeeds and the @var{controlled +text} is included; otherwise it is skipped. + +@node Defined +@subsection Defined + +@cindex @code{defined} +The special operator @code{defined} is used in @samp{#if} and +@samp{#elif} expressions to test whether a certain name is defined as a +macro. @code{defined @var{name}} and @code{defined (@var{name})} are +both expressions whose value is 1 if @var{name} is defined as a macro at +the current point in the program, and 0 otherwise. Thus, @code{@w{#if +defined MACRO}} is precisely equivalent to @code{@w{#ifdef MACRO}}. + +@code{defined} is useful when you wish to test more than one macro for +existence at once. For example, + +@smallexample +#if defined (__vax__) || defined (__ns16000__) +@end smallexample + +@noindent +would succeed if either of the names @code{__vax__} or +@code{__ns16000__} is defined as a macro. + +Conditionals written like this: + +@smallexample +#if defined BUFSIZE && BUFSIZE >= 1024 +@end smallexample + +@noindent +can generally be simplified to just @code{@w{#if BUFSIZE >= 1024}}, +since if @code{BUFSIZE} is not defined, it will be interpreted as having +the value zero. + +If the @code{defined} operator appears as a result of a macro expansion, +the C standard says the behavior is undefined. GNU cpp treats it as a +genuine @code{defined} operator and evaluates it normally. It will warn +wherever your code uses this feature if you use the command-line option +@option{-pedantic}, since other compilers may handle it differently. + +@node Else +@subsection Else + +@findex #else +The @samp{#else} directive can be added to a conditional to provide +alternative text to be used if the condition fails. This is what it +looks like: + +@smallexample +@group +#if @var{expression} +@var{text-if-true} +#else /* Not @var{expression} */ +@var{text-if-false} +#endif /* Not @var{expression} */ +@end group +@end smallexample + +@noindent +If @var{expression} is nonzero, the @var{text-if-true} is included and +the @var{text-if-false} is skipped. If @var{expression} is zero, the +opposite happens. + +You can use @samp{#else} with @samp{#ifdef} and @samp{#ifndef}, too. + +@node Elif +@subsection Elif + +@findex #elif +One common case of nested conditionals is used to check for more than two +possible alternatives. For example, you might have + +@smallexample +#if X == 1 +@dots{} +#else /* X != 1 */ +#if X == 2 +@dots{} +#else /* X != 2 */ +@dots{} +#endif /* X != 2 */ +#endif /* X != 1 */ +@end smallexample + +Another conditional directive, @samp{#elif}, allows this to be +abbreviated as follows: + +@smallexample +#if X == 1 +@dots{} +#elif X == 2 +@dots{} +#else /* X != 2 and X != 1*/ +@dots{} +#endif /* X != 2 and X != 1*/ +@end smallexample + +@samp{#elif} stands for ``else if''. Like @samp{#else}, it goes in the +middle of a conditional group and subdivides it; it does not require a +matching @samp{#endif} of its own. Like @samp{#if}, the @samp{#elif} +directive includes an expression to be tested. The text following the +@samp{#elif} is processed only if the original @samp{#if}-condition +failed and the @samp{#elif} condition succeeds. + +More than one @samp{#elif} can go in the same conditional group. Then +the text after each @samp{#elif} is processed only if the @samp{#elif} +condition succeeds after the original @samp{#if} and all previous +@samp{#elif} directives within it have failed. + +@samp{#else} is allowed after any number of @samp{#elif} directives, but +@samp{#elif} may not follow @samp{#else}. + +@node Deleted Code +@section Deleted Code +@cindex commenting out code + +If you replace or delete a part of the program but want to keep the old +code around for future reference, you often cannot simply comment it +out. Block comments do not nest, so the first comment inside the old +code will end the commenting-out. The probable result is a flood of +syntax errors. + +One way to avoid this problem is to use an always-false conditional +instead. For instance, put @code{#if 0} before the deleted code and +@code{#endif} after it. This works even if the code being turned +off contains conditionals, but they must be entire conditionals +(balanced @samp{#if} and @samp{#endif}). + +Some people use @code{#ifdef notdef} instead. This is risky, because +@code{notdef} might be accidentally defined as a macro, and then the +conditional would succeed. @code{#if 0} can be counted on to fail. + +Do not use @code{#if 0} for comments which are not C code. Use a real +comment, instead. The interior of @code{#if 0} must consist of complete +tokens; in particular, single-quote characters must balance. Comments +often contain unbalanced single-quote characters (known in English as +apostrophes). These confuse @code{#if 0}. They don't confuse +@samp{/*}. + +@node Diagnostics +@chapter Diagnostics +@cindex diagnostic +@cindex reporting errors +@cindex reporting warnings + +@findex #error +The directive @samp{#error} causes the preprocessor to report a fatal +error. The tokens forming the rest of the line following @samp{#error} +are used as the error message. + +You would use @samp{#error} inside of a conditional that detects a +combination of parameters which you know the program does not properly +support. For example, if you know that the program will not run +properly on a VAX, you might write + +@smallexample +@group +#ifdef __vax__ +#error "Won't work on VAXen. See comments at get_last_object." +#endif +@end group +@end smallexample + +If you have several configuration parameters that must be set up by +the installation in a consistent way, you can use conditionals to detect +an inconsistency and report it with @samp{#error}. For example, + +@smallexample +#if !defined(UNALIGNED_INT_ASM_OP) && defined(DWARF2_DEBUGGING_INFO) +#error "DWARF2_DEBUGGING_INFO requires UNALIGNED_INT_ASM_OP." +#endif +@end smallexample + +@findex #warning +The directive @samp{#warning} is like @samp{#error}, but causes the +preprocessor to issue a warning and continue preprocessing. The tokens +following @samp{#warning} are used as the warning message. + +You might use @samp{#warning} in obsolete header files, with a message +directing the user to the header file which should be used instead. + +Neither @samp{#error} nor @samp{#warning} macro-expands its argument. +Internal whitespace sequences are each replaced with a single space. +The line must consist of complete tokens. It is wisest to make the +argument of these directives be a single string constant; this avoids +problems with apostrophes and the like. + +@node Line Control +@chapter Line Control +@cindex line control + +The C preprocessor informs the C compiler of the location in your source +code where each token came from. Presently, this is just the file name +and line number. All the tokens resulting from macro expansion are +reported as having appeared on the line of the source file where the +outermost macro was used. We intend to be more accurate in the future. + +If you write a program which generates source code, such as the +@command{bison} parser generator, you may want to adjust the preprocessor's +notion of the current file name and line number by hand. Parts of the +output from @command{bison} are generated from scratch, other parts come +from a standard parser file. The rest are copied verbatim from +@command{bison}'s input. You would like compiler error messages and +symbolic debuggers to be able to refer to @code{bison}'s input file. + +@findex #line +@command{bison} or any such program can arrange this by writing +@samp{#line} directives into the output file. @samp{#line} is a +directive that specifies the original line number and source file name +for subsequent input in the current preprocessor input file. +@samp{#line} has three variants: + +@table @code +@item #line @var{linenum} +@var{linenum} is a non-negative decimal integer constant. It specifies +the line number which should be reported for the following line of +input. Subsequent lines are counted from @var{linenum}. + +@item #line @var{linenum} @var{filename} +@var{linenum} is the same as for the first form, and has the same +effect. In addition, @var{filename} is a string constant. The +following line and all subsequent lines are reported to come from the +file it specifies, until something else happens to change that. +@var{filename} is interpreted according to the normal rules for a string +constant: backslash escapes are interpreted. This is different from +@samp{#include}. + +Previous versions of CPP did not interpret escapes in @samp{#line}; +we have changed it because the standard requires they be interpreted, +and most other compilers do. + +@item #line @var{anything else} +@var{anything else} is checked for macro calls, which are expanded. +The result should match one of the above two forms. +@end table + +@samp{#line} directives alter the results of the @code{__FILE__} and +@code{__LINE__} predefined macros from that point on. @xref{Standard +Predefined Macros}. They do not have any effect on @samp{#include}'s +idea of the directory containing the current file. This is a change +from GCC 2.95. Previously, a file reading + +@smallexample +#line 1 "../src/gram.y" +#include "gram.h" +@end smallexample + +would search for @file{gram.h} in @file{../src}, then the @option{-I} +chain; the directory containing the physical source file would not be +searched. In GCC 3.0 and later, the @samp{#include} is not affected by +the presence of a @samp{#line} referring to a different directory. + +We made this change because the old behavior caused problems when +generated source files were transported between machines. For instance, +it is common practice to ship generated parsers with a source release, +so that people building the distribution do not need to have yacc or +Bison installed. These files frequently have @samp{#line} directives +referring to the directory tree of the system where the distribution was +created. If GCC tries to search for headers in those directories, the +build is likely to fail. + +The new behavior can cause failures too, if the generated file is not +in the same directory as its source and it attempts to include a header +which would be visible searching from the directory containing the +source file. However, this problem is easily solved with an additional +@option{-I} switch on the command line. The failures caused by the old +semantics could sometimes be corrected only by editing the generated +files, which is difficult and error-prone. + +@node Pragmas +@chapter Pragmas + +The @samp{#pragma} directive is the method specified by the C standard +for providing additional information to the compiler, beyond what is +conveyed in the language itself. Three forms of this directive +(commonly known as @dfn{pragmas}) are specified by the 1999 C standard. +A C compiler is free to attach any meaning it likes to other pragmas. + +GCC has historically preferred to use extensions to the syntax of the +language, such as @code{__attribute__}, for this purpose. However, GCC +does define a few pragmas of its own. These mostly have effects on the +entire translation unit or source file. + +In GCC version 3, all GNU-defined, supported pragmas have been given a +@code{GCC} prefix. This is in line with the @code{STDC} prefix on all +pragmas defined by C99. For backward compatibility, pragmas which were +recognized by previous versions are still recognized without the +@code{GCC} prefix, but that usage is deprecated. Some older pragmas are +deprecated in their entirety. They are not recognized with the +@code{GCC} prefix. @xref{Obsolete Features}. + +@cindex @code{_Pragma} +C99 introduces the @code{@w{_Pragma}} operator. This feature addresses a +major problem with @samp{#pragma}: being a directive, it cannot be +produced as the result of macro expansion. @code{@w{_Pragma}} is an +operator, much like @code{sizeof} or @code{defined}, and can be embedded +in a macro. + +Its syntax is @code{@w{_Pragma (@var{string-literal})}}, where +@var{string-literal} can be either a normal or wide-character string +literal. It is destringized, by replacing all @samp{\\} with a single +@samp{\} and all @samp{\"} with a @samp{"}. The result is then +processed as if it had appeared as the right hand side of a +@samp{#pragma} directive. For example, + +@smallexample +_Pragma ("GCC dependency \"parse.y\"") +@end smallexample + +@noindent +has the same effect as @code{#pragma GCC dependency "parse.y"}. The +same effect could be achieved using macros, for example + +@smallexample +#define DO_PRAGMA(x) _Pragma (#x) +DO_PRAGMA (GCC dependency "parse.y") +@end smallexample + +The standard is unclear on where a @code{_Pragma} operator can appear. +The preprocessor does not accept it within a preprocessing conditional +directive like @samp{#if}. To be safe, you are probably best keeping it +out of directives other than @samp{#define}, and putting it on a line of +its own. + +This manual documents the pragmas which are meaningful to the +preprocessor itself. Other pragmas are meaningful to the C or C++ +compilers. They are documented in the GCC manual. + +@ftable @code +@item #pragma GCC dependency +@code{#pragma GCC dependency} allows you to check the relative dates of +the current file and another file. If the other file is more recent than +the current file, a warning is issued. This is useful if the current +file is derived from the other file, and should be regenerated. The +other file is searched for using the normal include search path. +Optional trailing text can be used to give more information in the +warning message. + +@smallexample +#pragma GCC dependency "parse.y" +#pragma GCC dependency "/usr/include/time.h" rerun fixincludes +@end smallexample + +@item #pragma GCC poison +Sometimes, there is an identifier that you want to remove completely +from your program, and make sure that it never creeps back in. To +enforce this, you can @dfn{poison} the identifier with this pragma. +@code{#pragma GCC poison} is followed by a list of identifiers to +poison. If any of those identifiers appears anywhere in the source +after the directive, it is a hard error. For example, + +@smallexample +#pragma GCC poison printf sprintf fprintf +sprintf(some_string, "hello"); +@end smallexample + +@noindent +will produce an error. + +If a poisoned identifier appears as part of the expansion of a macro +which was defined before the identifier was poisoned, it will @emph{not} +cause an error. This lets you poison an identifier without worrying +about system headers defining macros that use it. + +For example, + +@smallexample +#define strrchr rindex +#pragma GCC poison rindex +strrchr(some_string, 'h'); +@end smallexample + +@noindent +will not produce an error. + +@item #pragma GCC system_header +This pragma takes no arguments. It causes the rest of the code in the +current file to be treated as if it came from a system header. +@xref{System Headers}. + +@end ftable + +@node Other Directives +@chapter Other Directives + +@findex #ident +@findex #sccs +The @samp{#ident} directive takes one argument, a string constant. On +some systems, that string constant is copied into a special segment of +the object file. On other systems, the directive is ignored. The +@samp{#sccs} directive is a synonym for @samp{#ident}. + +These directives are not part of the C standard, but they are not +official GNU extensions either. What historical information we have +been able to find, suggests they originated with System V@. + +@cindex null directive +The @dfn{null directive} consists of a @samp{#} followed by a newline, +with only whitespace (including comments) in between. A null directive +is understood as a preprocessing directive but has no effect on the +preprocessor output. The primary significance of the existence of the +null directive is that an input line consisting of just a @samp{#} will +produce no output, rather than a line of output containing just a +@samp{#}. Supposedly some old C programs contain such lines. + +@node Preprocessor Output +@chapter Preprocessor Output + +When the C preprocessor is used with the C, C++, or Objective-C +compilers, it is integrated into the compiler and communicates a stream +of binary tokens directly to the compiler's parser. However, it can +also be used in the more conventional standalone mode, where it produces +textual output. +@c FIXME: Document the library interface. + +@cindex output format +The output from the C preprocessor looks much like the input, except +that all preprocessing directive lines have been replaced with blank +lines and all comments with spaces. Long runs of blank lines are +discarded. + +The ISO standard specifies that it is implementation defined whether a +preprocessor preserves whitespace between tokens, or replaces it with +e.g.@: a single space. In GNU CPP, whitespace between tokens is collapsed +to become a single space, with the exception that the first token on a +non-directive line is preceded with sufficient spaces that it appears in +the same column in the preprocessed output that it appeared in the +original source file. This is so the output is easy to read. +@xref{Differences from previous versions}. CPP does not insert any +whitespace where there was none in the original source, except where +necessary to prevent an accidental token paste. + +@cindex linemarkers +Source file name and line number information is conveyed by lines +of the form + +@smallexample +# @var{linenum} @var{filename} @var{flags} +@end smallexample + +@noindent +These are called @dfn{linemarkers}. They are inserted as needed into +the output (but never within a string or character constant). They mean +that the following line originated in file @var{filename} at line +@var{linenum}. @var{filename} will never contain any non-printing +characters; they are replaced with octal escape sequences. + +After the file name comes zero or more flags, which are @samp{1}, +@samp{2}, @samp{3}, or @samp{4}. If there are multiple flags, spaces +separate them. Here is what the flags mean: + +@table @samp +@item 1 +This indicates the start of a new file. +@item 2 +This indicates returning to a file (after having included another file). +@item 3 +This indicates that the following text comes from a system header file, +so certain warnings should be suppressed. +@item 4 +This indicates that the following text should be treated as being +wrapped in an implicit @code{extern "C"} block. +@c maybe cross reference NO_IMPLICIT_EXTERN_C +@end table + +As an extension, the preprocessor accepts linemarkers in non-assembler +input files. They are treated like the corresponding @samp{#line} +directive, (@pxref{Line Control}), except that trailing flags are +permitted, and are interpreted with the meanings described above. If +multiple flags are given, they must be in ascending order. + +Some directives may be duplicated in the output of the preprocessor. +These are @samp{#ident} (always), @samp{#pragma} (only if the +preprocessor does not handle the pragma itself), and @samp{#define} and +@samp{#undef} (with certain debugging options). If this happens, the +@samp{#} of the directive will always be in the first column, and there +will be no space between the @samp{#} and the directive name. If macro +expansion happens to generate tokens which might be mistaken for a +duplicated directive, a space will be inserted between the @samp{#} and +the directive name. + +@node Traditional Mode +@chapter Traditional Mode + +Traditional (pre-standard) C preprocessing is rather different from +the preprocessing specified by the standard. When GCC is given the +@option{-traditional-cpp} option, it attempts to emulate a traditional +preprocessor. + +GCC versions 3.2 and later only support traditional mode semantics in +the preprocessor, and not in the compiler front ends. This chapter +outlines the traditional preprocessor semantics we implemented. + +The implementation does not correspond precisely to the behavior of +earlier versions of GCC, nor to any true traditional preprocessor. +After all, inconsistencies among traditional implementations were a +major motivation for C standardization. However, we intend that it +should be compatible with true traditional preprocessors in all ways +that actually matter. + +@menu +* Traditional lexical analysis:: +* Traditional macros:: +* Traditional miscellany:: +* Traditional warnings:: +@end menu + +@node Traditional lexical analysis +@section Traditional lexical analysis + +The traditional preprocessor does not decompose its input into tokens +the same way a standards-conforming preprocessor does. The input is +simply treated as a stream of text with minimal internal form. + +This implementation does not treat trigraphs (@pxref{trigraphs}) +specially since they were an invention of the standards committee. It +handles arbitrarily-positioned escaped newlines properly and splices +the lines as you would expect; many traditional preprocessors did not +do this. + +The form of horizontal whitespace in the input file is preserved in +the output. In particular, hard tabs remain hard tabs. This can be +useful if, for example, you are preprocessing a Makefile. + +Traditional CPP only recognizes C-style block comments, and treats the +@samp{/*} sequence as introducing a comment only if it lies outside +quoted text. Quoted text is introduced by the usual single and double +quotes, and also by an initial @samp{<} in a @code{#include} +directive. + +Traditionally, comments are completely removed and are not replaced +with a space. Since a traditional compiler does its own tokenization +of the output of the preprocessor, this means that comments can +effectively be used as token paste operators. However, comments +behave like separators for text handled by the preprocessor itself, +since it doesn't re-lex its input. For example, in + +@smallexample +#if foo/**/bar +@end smallexample + +@noindent +@samp{foo} and @samp{bar} are distinct identifiers and expanded +separately if they happen to be macros. In other words, this +directive is equivalent to + +@smallexample +#if foo bar +@end smallexample + +@noindent +rather than + +@smallexample +#if foobar +@end smallexample + +Generally speaking, in traditional mode an opening quote need not have +a matching closing quote. In particular, a macro may be defined with +replacement text that contains an unmatched quote. Of course, if you +attempt to compile preprocessed output containing an unmatched quote +you will get a syntax error. + +However, all preprocessing directives other than @code{#define} +require matching quotes. For example: + +@smallexample +#define m This macro's fine and has an unmatched quote +"/* This is not a comment. */ +/* @r{This is a comment. The following #include directive + is ill-formed.} */ +#include <stdio.h +@end smallexample + +Just as for the ISO preprocessor, what would be a closing quote can be +escaped with a backslash to prevent the quoted text from closing. + +@node Traditional macros +@section Traditional macros + +The major difference between traditional and ISO macros is that the +former expand to text rather than to a token sequence. CPP removes +all leading and trailing horizontal whitespace from a macro's +replacement text before storing it, but preserves the form of internal +whitespace. + +One consequence is that it is legitimate for the replacement text to +contain an unmatched quote (@pxref{Traditional lexical analysis}). An +unclosed string or character constant continues into the text +following the macro call. Similarly, the text at the end of a macro's +expansion can run together with the text after the macro invocation to +produce a single token. + +Normally comments are removed from the replacement text after the +macro is expanded, but if the @option{-CC} option is passed on the +command line comments are preserved. (In fact, the current +implementation removes comments even before saving the macro +replacement text, but it careful to do it in such a way that the +observed effect is identical even in the function-like macro case.) + +The ISO stringification operator @samp{#} and token paste operator +@samp{##} have no special meaning. As explained later, an effect +similar to these operators can be obtained in a different way. Macro +names that are embedded in quotes, either from the main file or after +macro replacement, do not expand. + +CPP replaces an unquoted object-like macro name with its replacement +text, and then rescans it for further macros to replace. Unlike +standard macro expansion, traditional macro expansion has no provision +to prevent recursion. If an object-like macro appears unquoted in its +replacement text, it will be replaced again during the rescan pass, +and so on @emph{ad infinitum}. GCC detects when it is expanding +recursive macros, emits an error message, and continues after the +offending macro invocation. + +@smallexample +#define PLUS + +#define INC(x) PLUS+x +INC(foo); + @expansion{} ++foo; +@end smallexample + +Function-like macros are similar in form but quite different in +behavior to their ISO counterparts. Their arguments are contained +within parentheses, are comma-separated, and can cross physical lines. +Commas within nested parentheses are not treated as argument +separators. Similarly, a quote in an argument cannot be left +unclosed; a following comma or parenthesis that comes before the +closing quote is treated like any other character. There is no +facility for handling variadic macros. + +This implementation removes all comments from macro arguments, unless +the @option{-C} option is given. The form of all other horizontal +whitespace in arguments is preserved, including leading and trailing +whitespace. In particular + +@smallexample +f( ) +@end smallexample + +@noindent +is treated as an invocation of the macro @samp{f} with a single +argument consisting of a single space. If you want to invoke a +function-like macro that takes no arguments, you must not leave any +whitespace between the parentheses. + +If a macro argument crosses a new line, the new line is replaced with +a space when forming the argument. If the previous line contained an +unterminated quote, the following line inherits the quoted state. + +Traditional preprocessors replace parameters in the replacement text +with their arguments regardless of whether the parameters are within +quotes or not. This provides a way to stringize arguments. For +example + +@smallexample +#define str(x) "x" +str(/* @r{A comment} */some text ) + @expansion{} "some text " +@end smallexample + +@noindent +Note that the comment is removed, but that the trailing space is +preserved. Here is an example of using a comment to effect token +pasting. + +@smallexample +#define suffix(x) foo_/**/x +suffix(bar) + @expansion{} foo_bar +@end smallexample + +@node Traditional miscellany +@section Traditional miscellany + +Here are some things to be aware of when using the traditional +preprocessor. + +@itemize @bullet +@item +Preprocessing directives are recognized only when their leading +@samp{#} appears in the first column. There can be no whitespace +between the beginning of the line and the @samp{#}, but whitespace can +follow the @samp{#}. + +@item +A true traditional C preprocessor does not recognize @samp{#error} or +@samp{#pragma}, and may not recognize @samp{#elif}. CPP supports all +the directives in traditional mode that it supports in ISO mode, +including extensions, with the exception that the effects of +@samp{#pragma GCC poison} are undefined. + +@item +__STDC__ is not defined. + +@item +If you use digraphs the behavior is undefined. + +@item +If a line that looks like a directive appears within macro arguments, +the behavior is undefined. + +@end itemize + +@node Traditional warnings +@section Traditional warnings +You can request warnings about features that did not exist, or worked +differently, in traditional C with the @option{-Wtraditional} option. +GCC does not warn about features of ISO C which you must use when you +are using a conforming compiler, such as the @samp{#} and @samp{##} +operators. + +Presently @option{-Wtraditional} warns about: + +@itemize @bullet +@item +Macro parameters that appear within string literals in the macro body. +In traditional C macro replacement takes place within string literals, +but does not in ISO C@. + +@item +In traditional C, some preprocessor directives did not exist. +Traditional preprocessors would only consider a line to be a directive +if the @samp{#} appeared in column 1 on the line. Therefore +@option{-Wtraditional} warns about directives that traditional C +understands but would ignore because the @samp{#} does not appear as the +first character on the line. It also suggests you hide directives like +@samp{#pragma} not understood by traditional C by indenting them. Some +traditional implementations would not recognize @samp{#elif}, so it +suggests avoiding it altogether. + +@item +A function-like macro that appears without an argument list. In some +traditional preprocessors this was an error. In ISO C it merely means +that the macro is not expanded. + +@item +The unary plus operator. This did not exist in traditional C@. + +@item +The @samp{U} and @samp{LL} integer constant suffixes, which were not +available in traditional C@. (Traditional C does support the @samp{L} +suffix for simple long integer constants.) You are not warned about +uses of these suffixes in macros defined in system headers. For +instance, @code{UINT_MAX} may well be defined as @code{4294967295U}, but +you will not be warned if you use @code{UINT_MAX}. + +You can usually avoid the warning, and the related warning about +constants which are so large that they are unsigned, by writing the +integer constant in question in hexadecimal, with no U suffix. Take +care, though, because this gives the wrong result in exotic cases. +@end itemize + +@node Implementation Details +@chapter Implementation Details + +Here we document details of how the preprocessor's implementation +affects its user-visible behavior. You should try to avoid undue +reliance on behavior described here, as it is possible that it will +change subtly in future implementations. + +Also documented here are obsolete features and changes from previous +versions of CPP@. + +@menu +* Implementation-defined behavior:: +* Implementation limits:: +* Obsolete Features:: +* Differences from previous versions:: +@end menu + +@node Implementation-defined behavior +@section Implementation-defined behavior +@cindex implementation-defined behavior + +This is how CPP behaves in all the cases which the C standard +describes as @dfn{implementation-defined}. This term means that the +implementation is free to do what it likes, but must document its choice +and stick to it. +@c FIXME: Check the C++ standard for more implementation-defined stuff. + +@itemize @bullet +@need 1000 +@item The mapping of physical source file multi-byte characters to the +execution character set. + +Currently, CPP requires its input to be ASCII or UTF-8. The execution +character set may be controlled by the user, with the +@option{-fexec-charset} and @option{-fwide-exec-charset} options. + +@item Identifier characters. +@anchor{Identifier characters} + +The C and C++ standards allow identifiers to be composed of @samp{_} +and the alphanumeric characters. C++ and C99 also allow universal +character names, and C99 further permits implementation-defined +characters. GCC currently only permits universal character names if +@option{-fextended-identifiers} is used, because the implementation of +universal character names in identifiers is experimental. + +GCC allows the @samp{$} character in identifiers as an extension for +most targets. This is true regardless of the @option{std=} switch, +since this extension cannot conflict with standards-conforming +programs. When preprocessing assembler, however, dollars are not +identifier characters by default. + +Currently the targets that by default do not permit @samp{$} are AVR, +IP2K, MMIX, MIPS Irix 3, ARM aout, and PowerPC targets for the AIX and +BeOS operating systems. + +You can override the default with @option{-fdollars-in-identifiers} or +@option{fno-dollars-in-identifiers}. @xref{fdollars-in-identifiers}. + +@item Non-empty sequences of whitespace characters. + +In textual output, each whitespace sequence is collapsed to a single +space. For aesthetic reasons, the first token on each non-directive +line of output is preceded with sufficient spaces that it appears in the +same column as it did in the original source file. + +@item The numeric value of character constants in preprocessor expressions. + +The preprocessor and compiler interpret character constants in the +same way; i.e.@: escape sequences such as @samp{\a} are given the +values they would have on the target machine. + +The compiler values a multi-character character constant a character +at a time, shifting the previous value left by the number of bits per +target character, and then or-ing in the bit-pattern of the new +character truncated to the width of a target character. The final +bit-pattern is given type @code{int}, and is therefore signed, +regardless of whether single characters are signed or not (a slight +change from versions 3.1 and earlier of GCC)@. If there are more +characters in the constant than would fit in the target @code{int} the +compiler issues a warning, and the excess leading characters are +ignored. + +For example, @code{'ab'} for a target with an 8-bit @code{char} would be +interpreted as @w{@samp{(int) ((unsigned char) 'a' * 256 + (unsigned char) +'b')}}, and @code{'\234a'} as @w{@samp{(int) ((unsigned char) '\234' * +256 + (unsigned char) 'a')}}. + +@item Source file inclusion. + +For a discussion on how the preprocessor locates header files, +@ref{Include Operation}. + +@item Interpretation of the filename resulting from a macro-expanded +@samp{#include} directive. + +@xref{Computed Includes}. + +@item Treatment of a @samp{#pragma} directive that after macro-expansion +results in a standard pragma. + +No macro expansion occurs on any @samp{#pragma} directive line, so the +question does not arise. + +Note that GCC does not yet implement any of the standard +pragmas. + +@end itemize + +@node Implementation limits +@section Implementation limits +@cindex implementation limits + +CPP has a small number of internal limits. This section lists the +limits which the C standard requires to be no lower than some minimum, +and all the others known. It is intended that there should be as few limits +as possible. If you encounter an undocumented or inconvenient limit, +please report that as a bug. @xref{Bugs, , Reporting Bugs, gcc, Using +the GNU Compiler Collection (GCC)}. + +Where we say something is limited @dfn{only by available memory}, that +means that internal data structures impose no intrinsic limit, and space +is allocated with @code{malloc} or equivalent. The actual limit will +therefore depend on many things, such as the size of other things +allocated by the compiler at the same time, the amount of memory +consumed by other processes on the same computer, etc. + +@itemize @bullet + +@item Nesting levels of @samp{#include} files. + +We impose an arbitrary limit of 200 levels, to avoid runaway recursion. +The standard requires at least 15 levels. + +@item Nesting levels of conditional inclusion. + +The C standard mandates this be at least 63. CPP is limited only by +available memory. + +@item Levels of parenthesized expressions within a full expression. + +The C standard requires this to be at least 63. In preprocessor +conditional expressions, it is limited only by available memory. + +@item Significant initial characters in an identifier or macro name. + +The preprocessor treats all characters as significant. The C standard +requires only that the first 63 be significant. + +@item Number of macros simultaneously defined in a single translation unit. + +The standard requires at least 4095 be possible. CPP is limited only +by available memory. + +@item Number of parameters in a macro definition and arguments in a macro call. + +We allow @code{USHRT_MAX}, which is no smaller than 65,535. The minimum +required by the standard is 127. + +@item Number of characters on a logical source line. + +The C standard requires a minimum of 4096 be permitted. CPP places +no limits on this, but you may get incorrect column numbers reported in +diagnostics for lines longer than 65,535 characters. + +@item Maximum size of a source file. + +The standard does not specify any lower limit on the maximum size of a +source file. GNU cpp maps files into memory, so it is limited by the +available address space. This is generally at least two gigabytes. +Depending on the operating system, the size of physical memory may or +may not be a limitation. + +@end itemize + +@node Obsolete Features +@section Obsolete Features + +CPP has a number of features which are present mainly for +compatibility with older programs. We discourage their use in new code. +In some cases, we plan to remove the feature in a future version of GCC@. + +@menu +* Assertions:: +* Obsolete once-only headers:: +@end menu + +@node Assertions +@subsection Assertions +@cindex assertions + +@dfn{Assertions} are a deprecated alternative to macros in writing +conditionals to test what sort of computer or system the compiled +program will run on. Assertions are usually predefined, but you can +define them with preprocessing directives or command-line options. + +Assertions were intended to provide a more systematic way to describe +the compiler's target system. However, in practice they are just as +unpredictable as the system-specific predefined macros. In addition, they +are not part of any standard, and only a few compilers support them. +Therefore, the use of assertions is @strong{less} portable than the use +of system-specific predefined macros. We recommend you do not use them at +all. + +@cindex predicates +An assertion looks like this: + +@smallexample +#@var{predicate} (@var{answer}) +@end smallexample + +@noindent +@var{predicate} must be a single identifier. @var{answer} can be any +sequence of tokens; all characters are significant except for leading +and trailing whitespace, and differences in internal whitespace +sequences are ignored. (This is similar to the rules governing macro +redefinition.) Thus, @code{(x + y)} is different from @code{(x+y)} but +equivalent to @code{@w{( x + y )}}. Parentheses do not nest inside an +answer. + +@cindex testing predicates +To test an assertion, you write it in an @samp{#if}. For example, this +conditional succeeds if either @code{vax} or @code{ns16000} has been +asserted as an answer for @code{machine}. + +@smallexample +#if #machine (vax) || #machine (ns16000) +@end smallexample + +@noindent +You can test whether @emph{any} answer is asserted for a predicate by +omitting the answer in the conditional: + +@smallexample +#if #machine +@end smallexample + +@findex #assert +Assertions are made with the @samp{#assert} directive. Its sole +argument is the assertion to make, without the leading @samp{#} that +identifies assertions in conditionals. + +@smallexample +#assert @var{predicate} (@var{answer}) +@end smallexample + +@noindent +You may make several assertions with the same predicate and different +answers. Subsequent assertions do not override previous ones for the +same predicate. All the answers for any given predicate are +simultaneously true. + +@cindex assertions, canceling +@findex #unassert +Assertions can be canceled with the @samp{#unassert} directive. It +has the same syntax as @samp{#assert}. In that form it cancels only the +answer which was specified on the @samp{#unassert} line; other answers +for that predicate remain true. You can cancel an entire predicate by +leaving out the answer: + +@smallexample +#unassert @var{predicate} +@end smallexample + +@noindent +In either form, if no such assertion has been made, @samp{#unassert} has +no effect. + +You can also make or cancel assertions using command line options. +@xref{Invocation}. + +@node Obsolete once-only headers +@subsection Obsolete once-only headers + +CPP supports two more ways of indicating that a header file should be +read only once. Neither one is as portable as a wrapper @samp{#ifndef}, +and we recommend you do not use them in new programs. + +@findex #import +In the Objective-C language, there is a variant of @samp{#include} +called @samp{#import} which includes a file, but does so at most once. +If you use @samp{#import} instead of @samp{#include}, then you don't +need the conditionals inside the header file to prevent multiple +inclusion of the contents. GCC permits the use of @samp{#import} in C +and C++ as well as Objective-C@. However, it is not in standard C or C++ +and should therefore not be used by portable programs. + +@samp{#import} is not a well designed feature. It requires the users of +a header file to know that it should only be included once. It is much +better for the header file's implementor to write the file so that users +don't need to know this. Using a wrapper @samp{#ifndef} accomplishes +this goal. + +In the present implementation, a single use of @samp{#import} will +prevent the file from ever being read again, by either @samp{#import} or +@samp{#include}. You should not rely on this; do not use both +@samp{#import} and @samp{#include} to refer to the same header file. + +Another way to prevent a header file from being included more than once +is with the @samp{#pragma once} directive. If @samp{#pragma once} is +seen when scanning a header file, that file will never be read again, no +matter what. + +@samp{#pragma once} does not have the problems that @samp{#import} does, +but it is not recognized by all preprocessors, so you cannot rely on it +in a portable program. + +@node Differences from previous versions +@section Differences from previous versions +@cindex differences from previous versions + +This section details behavior which has changed from previous versions +of CPP@. We do not plan to change it again in the near future, but +we do not promise not to, either. + +The ``previous versions'' discussed here are 2.95 and before. The +behavior of GCC 3.0 is mostly the same as the behavior of the widely +used 2.96 and 2.97 development snapshots. Where there are differences, +they generally represent bugs in the snapshots. + +@itemize @bullet + +@item -I- deprecated + +This option has been deprecated in 4.0. @option{-iquote} is meant to +replace the need for this option. + +@item Order of evaluation of @samp{#} and @samp{##} operators + +The standard does not specify the order of evaluation of a chain of +@samp{##} operators, nor whether @samp{#} is evaluated before, after, or +at the same time as @samp{##}. You should therefore not write any code +which depends on any specific ordering. It is possible to guarantee an +ordering, if you need one, by suitable use of nested macros. + +An example of where this might matter is pasting the arguments @samp{1}, +@samp{e} and @samp{-2}. This would be fine for left-to-right pasting, +but right-to-left pasting would produce an invalid token @samp{e-2}. + +GCC 3.0 evaluates @samp{#} and @samp{##} at the same time and strictly +left to right. Older versions evaluated all @samp{#} operators first, +then all @samp{##} operators, in an unreliable order. + +@item The form of whitespace between tokens in preprocessor output + +@xref{Preprocessor Output}, for the current textual format. This is +also the format used by stringification. Normally, the preprocessor +communicates tokens directly to the compiler's parser, and whitespace +does not come up at all. + +Older versions of GCC preserved all whitespace provided by the user and +inserted lots more whitespace of their own, because they could not +accurately predict when extra spaces were needed to prevent accidental +token pasting. + +@item Optional argument when invoking rest argument macros + +As an extension, GCC permits you to omit the variable arguments entirely +when you use a variable argument macro. This is forbidden by the 1999 C +standard, and will provoke a pedantic warning with GCC 3.0. Previous +versions accepted it silently. + +@item @samp{##} swallowing preceding text in rest argument macros + +Formerly, in a macro expansion, if @samp{##} appeared before a variable +arguments parameter, and the set of tokens specified for that argument +in the macro invocation was empty, previous versions of CPP would +back up and remove the preceding sequence of non-whitespace characters +(@strong{not} the preceding token). This extension is in direct +conflict with the 1999 C standard and has been drastically pared back. + +In the current version of the preprocessor, if @samp{##} appears between +a comma and a variable arguments parameter, and the variable argument is +omitted entirely, the comma will be removed from the expansion. If the +variable argument is empty, or the token before @samp{##} is not a +comma, then @samp{##} behaves as a normal token paste. + +@item @samp{#line} and @samp{#include} + +The @samp{#line} directive used to change GCC's notion of the +``directory containing the current file'', used by @samp{#include} with +a double-quoted header file name. In 3.0 and later, it does not. +@xref{Line Control}, for further explanation. + +@item Syntax of @samp{#line} + +In GCC 2.95 and previous, the string constant argument to @samp{#line} +was treated the same way as the argument to @samp{#include}: backslash +escapes were not honored, and the string ended at the second @samp{"}. +This is not compliant with the C standard. In GCC 3.0, an attempt was +made to correct the behavior, so that the string was treated as a real +string constant, but it turned out to be buggy. In 3.1, the bugs have +been fixed. (We are not fixing the bugs in 3.0 because they affect +relatively few people and the fix is quite invasive.) + +@end itemize + +@node Invocation +@chapter Invocation +@cindex invocation +@cindex command line + +Most often when you use the C preprocessor you will not have to invoke it +explicitly: the C compiler will do so automatically. However, the +preprocessor is sometimes useful on its own. All the options listed +here are also acceptable to the C compiler and have the same meaning, +except that the C compiler has different rules for specifying the output +file. + +@emph{Note:} Whether you use the preprocessor by way of @command{gcc} +or @command{cpp}, the @dfn{compiler driver} is run first. This +program's purpose is to translate your command into invocations of the +programs that do the actual work. Their command line interfaces are +similar but not identical to the documented interface, and may change +without notice. + +@ignore +@c man begin SYNOPSIS +cpp [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}] + [@option{-I}@var{dir}@dots{}] [@option{-iquote}@var{dir}@dots{}] + [@option{-W}@var{warn}@dots{}] + [@option{-M}|@option{-MM}] [@option{-MG}] [@option{-MF} @var{filename}] + [@option{-MP}] [@option{-MQ} @var{target}@dots{}] + [@option{-MT} @var{target}@dots{}] + [@option{-P}] [@option{-fno-working-directory}] + [@option{-x} @var{language}] [@option{-std=}@var{standard}] + @var{infile} @var{outfile} + +Only the most useful options are listed here; see below for the remainder. +@c man end +@c man begin SEEALSO +gpl(7), gfdl(7), fsf-funding(7), +gcc(1), as(1), ld(1), and the Info entries for @file{cpp}, @file{gcc}, and +@file{binutils}. +@c man end +@end ignore + +@c man begin OPTIONS +The C preprocessor expects two file names as arguments, @var{infile} and +@var{outfile}. The preprocessor reads @var{infile} together with any +other files it specifies with @samp{#include}. All the output generated +by the combined input files is written in @var{outfile}. + +Either @var{infile} or @var{outfile} may be @option{-}, which as +@var{infile} means to read from standard input and as @var{outfile} +means to write to standard output. Also, if either file is omitted, it +means the same as if @option{-} had been specified for that file. + +Unless otherwise noted, or the option ends in @samp{=}, all options +which take an argument may have that argument appear either immediately +after the option, or with a space between option and argument: +@option{-Ifoo} and @option{-I foo} have the same effect. + +@cindex grouping options +@cindex options, grouping +Many options have multi-letter names; therefore multiple single-letter +options may @emph{not} be grouped: @option{-dM} is very different from +@w{@samp{-d -M}}. + +@cindex options +@include cppopts.texi +@c man end + +@node Environment Variables +@chapter Environment Variables +@cindex environment variables +@c man begin ENVIRONMENT + +This section describes the environment variables that affect how CPP +operates. You can use them to specify directories or prefixes to use +when searching for include files, or to control dependency output. + +Note that you can also specify places to search using options such as +@option{-I}, and control dependency output with options like +@option{-M} (@pxref{Invocation}). These take precedence over +environment variables, which in turn take precedence over the +configuration of GCC@. + +@include cppenv.texi +@c man end + +@page +@include fdl.texi + +@page +@node Index of Directives +@unnumbered Index of Directives +@printindex fn + +@node Option Index +@unnumbered Option Index +@noindent +CPP's command line options and environment variables are indexed here +without any initial @samp{-} or @samp{--}. +@printindex op + +@page +@node Concept Index +@unnumbered Concept Index +@printindex cp + +@bye diff --git a/gcc-4.2.1-5666.3/gcc/doc/cppenv.texi b/gcc-4.2.1-5666.3/gcc/doc/cppenv.texi new file mode 100644 index 000000000..bb29cb2d1 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/cppenv.texi @@ -0,0 +1,83 @@ +@c Copyright (c) 1999, 2000, 2001, 2002, 2004 +@c Free Software Foundation, Inc. +@c This is part of the CPP and GCC manuals. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Environment variables affecting the preprocessor +@c --------------------------------------------------------------------- + +@c If this file is included with the flag ``cppmanual'' set, it is +@c formatted for inclusion in the CPP manual; otherwise the main GCC manual. + +@vtable @env +@item CPATH +@itemx C_INCLUDE_PATH +@itemx CPLUS_INCLUDE_PATH +@itemx OBJC_INCLUDE_PATH +@c Commented out until ObjC++ is part of GCC: +@c @itemx OBJCPLUS_INCLUDE_PATH +Each variable's value is a list of directories separated by a special +character, much like @env{PATH}, in which to look for header files. +The special character, @code{PATH_SEPARATOR}, is target-dependent and +determined at GCC build time. For Microsoft Windows-based targets it is a +semicolon, and for almost all other targets it is a colon. + +@env{CPATH} specifies a list of directories to be searched as if +specified with @option{-I}, but after any paths given with @option{-I} +options on the command line. This environment variable is used +regardless of which language is being preprocessed. + +The remaining environment variables apply only when preprocessing the +particular language indicated. Each specifies a list of directories +to be searched as if specified with @option{-isystem}, but after any +paths given with @option{-isystem} options on the command line. + +In all these variables, an empty element instructs the compiler to +search its current working directory. Empty elements can appear at the +beginning or end of a path. For instance, if the value of +@env{CPATH} is @code{:/special/include}, that has the same +effect as @samp{@w{-I. -I/special/include}}. + +@c man end +@ifset cppmanual +See also @ref{Search Path}. +@end ifset +@c man begin ENVIRONMENT + +@item DEPENDENCIES_OUTPUT +@cindex dependencies for make as output +If this variable is set, its value specifies how to output +dependencies for Make based on the non-system header files processed +by the compiler. System header files are ignored in the dependency +output. + +The value of @env{DEPENDENCIES_OUTPUT} can be just a file name, in +which case the Make rules are written to that file, guessing the target +name from the source file name. Or the value can have the form +@samp{@var{file} @var{target}}, in which case the rules are written to +file @var{file} using @var{target} as the target name. + +In other words, this environment variable is equivalent to combining +the options @option{-MM} and @option{-MF} +@ifset cppmanual +(@pxref{Invocation}), +@end ifset +@ifclear cppmanual +(@pxref{Preprocessor Options}), +@end ifclear +with an optional @option{-MT} switch too. + +@item SUNPRO_DEPENDENCIES +@cindex dependencies for make as output +This variable is the same as @env{DEPENDENCIES_OUTPUT} (see above), +except that system header files are not ignored, so it implies +@option{-M} rather than @option{-MM}. However, the dependence on the +main input file is omitted. +@ifset cppmanual +@xref{Invocation}. +@end ifset +@ifclear cppmanual +@xref{Preprocessor Options}. +@end ifclear +@end vtable diff --git a/gcc-4.2.1-5666.3/gcc/doc/cppinternals.texi b/gcc-4.2.1-5666.3/gcc/doc/cppinternals.texi new file mode 100644 index 000000000..ff6acc3fb --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/cppinternals.texi @@ -0,0 +1,1065 @@ +\input texinfo +@setfilename cppinternals.info +@settitle The GNU C Preprocessor Internals + +@include gcc-common.texi + +@ifinfo +@dircategory Software development +@direntry +* Cpplib: (cppinternals). Cpplib internals. +@end direntry +@end ifinfo + +@c @smallbook +@c @cropmarks +@c @finalout +@setchapternewpage odd +@ifinfo +This file documents the internals of the GNU C Preprocessor. + +Copyright 2000, 2001, 2002, 2004, 2005 Free Software Foundation, Inc. + +Permission is granted to make and distribute verbatim copies of +this manual provided the copyright notice and this permission notice +are preserved on all copies. + +@ignore +Permission is granted to process this file through Tex and print the +results, provided the printed document carries copying permission +notice identical to this one except for the removal of this paragraph +(this paragraph not being relevant to the printed manual). + +@end ignore +Permission is granted to copy and distribute modified versions of this +manual under the conditions for verbatim copying, provided also that +the entire resulting derived work is distributed under the terms of a +permission notice identical to this one. + +Permission is granted to copy and distribute translations of this manual +into another language, under the above conditions for modified versions. +@end ifinfo + +@titlepage +@title Cpplib Internals +@versionsubtitle +@author Neil Booth +@page +@vskip 0pt plus 1filll +@c man begin COPYRIGHT +Copyright @copyright{} 2000, 2001, 2002, 2004, 2005 +Free Software Foundation, Inc. + +Permission is granted to make and distribute verbatim copies of +this manual provided the copyright notice and this permission notice +are preserved on all copies. + +Permission is granted to copy and distribute modified versions of this +manual under the conditions for verbatim copying, provided also that +the entire resulting derived work is distributed under the terms of a +permission notice identical to this one. + +Permission is granted to copy and distribute translations of this manual +into another language, under the above conditions for modified versions. +@c man end +@end titlepage +@contents +@page + +@node Top +@top +@chapter Cpplib---the GNU C Preprocessor + +The GNU C preprocessor is +implemented as a library, @dfn{cpplib}, so it can be easily shared between +a stand-alone preprocessor, and a preprocessor integrated with the C, +C++ and Objective-C front ends. It is also available for use by other +programs, though this is not recommended as its exposed interface has +not yet reached a point of reasonable stability. + +The library has been written to be re-entrant, so that it can be used +to preprocess many files simultaneously if necessary. It has also been +written with the preprocessing token as the fundamental unit; the +preprocessor in previous versions of GCC would operate on text strings +as the fundamental unit. + +This brief manual documents the internals of cpplib, and explains some +of the tricky issues. It is intended that, along with the comments in +the source code, a reasonably competent C programmer should be able to +figure out what the code is doing, and why things have been implemented +the way they have. + +@menu +* Conventions:: Conventions used in the code. +* Lexer:: The combined C, C++ and Objective-C Lexer. +* Hash Nodes:: All identifiers are entered into a hash table. +* Macro Expansion:: Macro expansion algorithm. +* Token Spacing:: Spacing and paste avoidance issues. +* Line Numbering:: Tracking location within files. +* Guard Macros:: Optimizing header files with guard macros. +* Files:: File handling. +* Concept Index:: Index. +@end menu + +@node Conventions +@unnumbered Conventions +@cindex interface +@cindex header files + +cpplib has two interfaces---one is exposed internally only, and the +other is for both internal and external use. + +The convention is that functions and types that are exposed to multiple +files internally are prefixed with @samp{_cpp_}, and are to be found in +the file @file{internal.h}. Functions and types exposed to external +clients are in @file{cpplib.h}, and prefixed with @samp{cpp_}. For +historical reasons this is no longer quite true, but we should strive to +stick to it. + +We are striving to reduce the information exposed in @file{cpplib.h} to the +bare minimum necessary, and then to keep it there. This makes clear +exactly what external clients are entitled to assume, and allows us to +change internals in the future without worrying whether library clients +are perhaps relying on some kind of undocumented implementation-specific +behavior. + +@node Lexer +@unnumbered The Lexer +@cindex lexer +@cindex newlines +@cindex escaped newlines + +@section Overview +The lexer is contained in the file @file{lex.c}. It is a hand-coded +lexer, and not implemented as a state machine. It can understand C, C++ +and Objective-C source code, and has been extended to allow reasonably +successful preprocessing of assembly language. The lexer does not make +an initial pass to strip out trigraphs and escaped newlines, but handles +them as they are encountered in a single pass of the input file. It +returns preprocessing tokens individually, not a line at a time. + +It is mostly transparent to users of the library, since the library's +interface for obtaining the next token, @code{cpp_get_token}, takes care +of lexing new tokens, handling directives, and expanding macros as +necessary. However, the lexer does expose some functionality so that +clients of the library can easily spell a given token, such as +@code{cpp_spell_token} and @code{cpp_token_len}. These functions are +useful when generating diagnostics, and for emitting the preprocessed +output. + +@section Lexing a token +Lexing of an individual token is handled by @code{_cpp_lex_direct} and +its subroutines. In its current form the code is quite complicated, +with read ahead characters and such-like, since it strives to not step +back in the character stream in preparation for handling non-ASCII file +encodings. The current plan is to convert any such files to UTF-8 +before processing them. This complexity is therefore unnecessary and +will be removed, so I'll not discuss it further here. + +The job of @code{_cpp_lex_direct} is simply to lex a token. It is not +responsible for issues like directive handling, returning lookahead +tokens directly, multiple-include optimization, or conditional block +skipping. It necessarily has a minor r@^ole to play in memory +management of lexed lines. I discuss these issues in a separate section +(@pxref{Lexing a line}). + +The lexer places the token it lexes into storage pointed to by the +variable @code{cur_token}, and then increments it. This variable is +important for correct diagnostic positioning. Unless a specific line +and column are passed to the diagnostic routines, they will examine the +@code{line} and @code{col} values of the token just before the location +that @code{cur_token} points to, and use that location to report the +diagnostic. + +The lexer does not consider whitespace to be a token in its own right. +If whitespace (other than a new line) precedes a token, it sets the +@code{PREV_WHITE} bit in the token's flags. Each token has its +@code{line} and @code{col} variables set to the line and column of the +first character of the token. This line number is the line number in +the translation unit, and can be converted to a source (file, line) pair +using the line map code. + +The first token on a logical, i.e.@: unescaped, line has the flag +@code{BOL} set for beginning-of-line. This flag is intended for +internal use, both to distinguish a @samp{#} that begins a directive +from one that doesn't, and to generate a call-back to clients that want +to be notified about the start of every non-directive line with tokens +on it. Clients cannot reliably determine this for themselves: the first +token might be a macro, and the tokens of a macro expansion do not have +the @code{BOL} flag set. The macro expansion may even be empty, and the +next token on the line certainly won't have the @code{BOL} flag set. + +New lines are treated specially; exactly how the lexer handles them is +context-dependent. The C standard mandates that directives are +terminated by the first unescaped newline character, even if it appears +in the middle of a macro expansion. Therefore, if the state variable +@code{in_directive} is set, the lexer returns a @code{CPP_EOF} token, +which is normally used to indicate end-of-file, to indicate +end-of-directive. In a directive a @code{CPP_EOF} token never means +end-of-file. Conveniently, if the caller was @code{collect_args}, it +already handles @code{CPP_EOF} as if it were end-of-file, and reports an +error about an unterminated macro argument list. + +The C standard also specifies that a new line in the middle of the +arguments to a macro is treated as whitespace. This white space is +important in case the macro argument is stringified. The state variable +@code{parsing_args} is nonzero when the preprocessor is collecting the +arguments to a macro call. It is set to 1 when looking for the opening +parenthesis to a function-like macro, and 2 when collecting the actual +arguments up to the closing parenthesis, since these two cases need to +be distinguished sometimes. One such time is here: the lexer sets the +@code{PREV_WHITE} flag of a token if it meets a new line when +@code{parsing_args} is set to 2. It doesn't set it if it meets a new +line when @code{parsing_args} is 1, since then code like + +@smallexample +#define foo() bar +foo +baz +@end smallexample + +@noindent would be output with an erroneous space before @samp{baz}: + +@smallexample +foo + baz +@end smallexample + +This is a good example of the subtlety of getting token spacing correct +in the preprocessor; there are plenty of tests in the testsuite for +corner cases like this. + +The lexer is written to treat each of @samp{\r}, @samp{\n}, @samp{\r\n} +and @samp{\n\r} as a single new line indicator. This allows it to +transparently preprocess MS-DOS, Macintosh and Unix files without their +needing to pass through a special filter beforehand. + +We also decided to treat a backslash, either @samp{\} or the trigraph +@samp{??/}, separated from one of the above newline indicators by +non-comment whitespace only, as intending to escape the newline. It +tends to be a typing mistake, and cannot reasonably be mistaken for +anything else in any of the C-family grammars. Since handling it this +way is not strictly conforming to the ISO standard, the library issues a +warning wherever it encounters it. + +Handling newlines like this is made simpler by doing it in one place +only. The function @code{handle_newline} takes care of all newline +characters, and @code{skip_escaped_newlines} takes care of arbitrarily +long sequences of escaped newlines, deferring to @code{handle_newline} +to handle the newlines themselves. + +The most painful aspect of lexing ISO-standard C and C++ is handling +trigraphs and backlash-escaped newlines. Trigraphs are processed before +any interpretation of the meaning of a character is made, and unfortunately +there is a trigraph representation for a backslash, so it is possible for +the trigraph @samp{??/} to introduce an escaped newline. + +Escaped newlines are tedious because theoretically they can occur +anywhere---between the @samp{+} and @samp{=} of the @samp{+=} token, +within the characters of an identifier, and even between the @samp{*} +and @samp{/} that terminates a comment. Moreover, you cannot be sure +there is just one---there might be an arbitrarily long sequence of them. + +So, for example, the routine that lexes a number, @code{parse_number}, +cannot assume that it can scan forwards until the first non-number +character and be done with it, because this could be the @samp{\} +introducing an escaped newline, or the @samp{?} introducing the trigraph +sequence that represents the @samp{\} of an escaped newline. If it +encounters a @samp{?} or @samp{\}, it calls @code{skip_escaped_newlines} +to skip over any potential escaped newlines before checking whether the +number has been finished. + +Similarly code in the main body of @code{_cpp_lex_direct} cannot simply +check for a @samp{=} after a @samp{+} character to determine whether it +has a @samp{+=} token; it needs to be prepared for an escaped newline of +some sort. Such cases use the function @code{get_effective_char}, which +returns the first character after any intervening escaped newlines. + +The lexer needs to keep track of the correct column position, including +counting tabs as specified by the @option{-ftabstop=} option. This +should be done even within C-style comments; they can appear in the +middle of a line, and we want to report diagnostics in the correct +position for text appearing after the end of the comment. + +@anchor{Invalid identifiers} +Some identifiers, such as @code{__VA_ARGS__} and poisoned identifiers, +may be invalid and require a diagnostic. However, if they appear in a +macro expansion we don't want to complain with each use of the macro. +It is therefore best to catch them during the lexing stage, in +@code{parse_identifier}. In both cases, whether a diagnostic is needed +or not is dependent upon the lexer's state. For example, we don't want +to issue a diagnostic for re-poisoning a poisoned identifier, or for +using @code{__VA_ARGS__} in the expansion of a variable-argument macro. +Therefore @code{parse_identifier} makes use of state flags to determine +whether a diagnostic is appropriate. Since we change state on a +per-token basis, and don't lex whole lines at a time, this is not a +problem. + +Another place where state flags are used to change behavior is whilst +lexing header names. Normally, a @samp{<} would be lexed as a single +token. After a @code{#include} directive, though, it should be lexed as +a single token as far as the nearest @samp{>} character. Note that we +don't allow the terminators of header names to be escaped; the first +@samp{"} or @samp{>} terminates the header name. + +Interpretation of some character sequences depends upon whether we are +lexing C, C++ or Objective-C, and on the revision of the standard in +force. For example, @samp{::} is a single token in C++, but in C it is +two separate @samp{:} tokens and almost certainly a syntax error. Such +cases are handled by @code{_cpp_lex_direct} based upon command-line +flags stored in the @code{cpp_options} structure. + +Once a token has been lexed, it leads an independent existence. The +spelling of numbers, identifiers and strings is copied to permanent +storage from the original input buffer, so a token remains valid and +correct even if its source buffer is freed with @code{_cpp_pop_buffer}. +The storage holding the spellings of such tokens remains until the +client program calls cpp_destroy, probably at the end of the translation +unit. + +@anchor{Lexing a line} +@section Lexing a line +@cindex token run + +When the preprocessor was changed to return pointers to tokens, one +feature I wanted was some sort of guarantee regarding how long a +returned pointer remains valid. This is important to the stand-alone +preprocessor, the future direction of the C family front ends, and even +to cpplib itself internally. + +Occasionally the preprocessor wants to be able to peek ahead in the +token stream. For example, after the name of a function-like macro, it +wants to check the next token to see if it is an opening parenthesis. +Another example is that, after reading the first few tokens of a +@code{#pragma} directive and not recognizing it as a registered pragma, +it wants to backtrack and allow the user-defined handler for unknown +pragmas to access the full @code{#pragma} token stream. The stand-alone +preprocessor wants to be able to test the current token with the +previous one to see if a space needs to be inserted to preserve their +separate tokenization upon re-lexing (paste avoidance), so it needs to +be sure the pointer to the previous token is still valid. The +recursive-descent C++ parser wants to be able to perform tentative +parsing arbitrarily far ahead in the token stream, and then to be able +to jump back to a prior position in that stream if necessary. + +The rule I chose, which is fairly natural, is to arrange that the +preprocessor lex all tokens on a line consecutively into a token buffer, +which I call a @dfn{token run}, and when meeting an unescaped new line +(newlines within comments do not count either), to start lexing back at +the beginning of the run. Note that we do @emph{not} lex a line of +tokens at once; if we did that @code{parse_identifier} would not have +state flags available to warn about invalid identifiers (@pxref{Invalid +identifiers}). + +In other words, accessing tokens that appeared earlier in the current +line is valid, but since each logical line overwrites the tokens of the +previous line, tokens from prior lines are unavailable. In particular, +since a directive only occupies a single logical line, this means that +the directive handlers like the @code{#pragma} handler can jump around +in the directive's tokens if necessary. + +Two issues remain: what about tokens that arise from macro expansions, +and what happens when we have a long line that overflows the token run? + +Since we promise clients that we preserve the validity of pointers that +we have already returned for tokens that appeared earlier in the line, +we cannot reallocate the run. Instead, on overflow it is expanded by +chaining a new token run on to the end of the existing one. + +The tokens forming a macro's replacement list are collected by the +@code{#define} handler, and placed in storage that is only freed by +@code{cpp_destroy}. So if a macro is expanded in the line of tokens, +the pointers to the tokens of its expansion that are returned will always +remain valid. However, macros are a little trickier than that, since +they give rise to three sources of fresh tokens. They are the built-in +macros like @code{__LINE__}, and the @samp{#} and @samp{##} operators +for stringification and token pasting. I handled this by allocating +space for these tokens from the lexer's token run chain. This means +they automatically receive the same lifetime guarantees as lexed tokens, +and we don't need to concern ourselves with freeing them. + +Lexing into a line of tokens solves some of the token memory management +issues, but not all. The opening parenthesis after a function-like +macro name might lie on a different line, and the front ends definitely +want the ability to look ahead past the end of the current line. So +cpplib only moves back to the start of the token run at the end of a +line if the variable @code{keep_tokens} is zero. Line-buffering is +quite natural for the preprocessor, and as a result the only time cpplib +needs to increment this variable is whilst looking for the opening +parenthesis to, and reading the arguments of, a function-like macro. In +the near future cpplib will export an interface to increment and +decrement this variable, so that clients can share full control over the +lifetime of token pointers too. + +The routine @code{_cpp_lex_token} handles moving to new token runs, +calling @code{_cpp_lex_direct} to lex new tokens, or returning +previously-lexed tokens if we stepped back in the token stream. It also +checks each token for the @code{BOL} flag, which might indicate a +directive that needs to be handled, or require a start-of-line call-back +to be made. @code{_cpp_lex_token} also handles skipping over tokens in +failed conditional blocks, and invalidates the control macro of the +multiple-include optimization if a token was successfully lexed outside +a directive. In other words, its callers do not need to concern +themselves with such issues. + +@node Hash Nodes +@unnumbered Hash Nodes +@cindex hash table +@cindex identifiers +@cindex macros +@cindex assertions +@cindex named operators + +When cpplib encounters an ``identifier'', it generates a hash code for +it and stores it in the hash table. By ``identifier'' we mean tokens +with type @code{CPP_NAME}; this includes identifiers in the usual C +sense, as well as keywords, directive names, macro names and so on. For +example, all of @code{pragma}, @code{int}, @code{foo} and +@code{__GNUC__} are identifiers and hashed when lexed. + +Each node in the hash table contain various information about the +identifier it represents. For example, its length and type. At any one +time, each identifier falls into exactly one of three categories: + +@itemize @bullet +@item Macros + +These have been declared to be macros, either on the command line or +with @code{#define}. A few, such as @code{__TIME__} are built-ins +entered in the hash table during initialization. The hash node for a +normal macro points to a structure with more information about the +macro, such as whether it is function-like, how many arguments it takes, +and its expansion. Built-in macros are flagged as special, and instead +contain an enum indicating which of the various built-in macros it is. + +@item Assertions + +Assertions are in a separate namespace to macros. To enforce this, cpp +actually prepends a @code{#} character before hashing and entering it in +the hash table. An assertion's node points to a chain of answers to +that assertion. + +@item Void + +Everything else falls into this category---an identifier that is not +currently a macro, or a macro that has since been undefined with +@code{#undef}. + +When preprocessing C++, this category also includes the named operators, +such as @code{xor}. In expressions these behave like the operators they +represent, but in contexts where the spelling of a token matters they +are spelt differently. This spelling distinction is relevant when they +are operands of the stringizing and pasting macro operators @code{#} and +@code{##}. Named operator hash nodes are flagged, both to catch the +spelling distinction and to prevent them from being defined as macros. +@end itemize + +The same identifiers share the same hash node. Since each identifier +token, after lexing, contains a pointer to its hash node, this is used +to provide rapid lookup of various information. For example, when +parsing a @code{#define} statement, CPP flags each argument's identifier +hash node with the index of that argument. This makes duplicated +argument checking an O(1) operation for each argument. Similarly, for +each identifier in the macro's expansion, lookup to see if it is an +argument, and which argument it is, is also an O(1) operation. Further, +each directive name, such as @code{endif}, has an associated directive +enum stored in its hash node, so that directive lookup is also O(1). + +@node Macro Expansion +@unnumbered Macro Expansion Algorithm +@cindex macro expansion + +Macro expansion is a tricky operation, fraught with nasty corner cases +and situations that render what you thought was a nifty way to +optimize the preprocessor's expansion algorithm wrong in quite subtle +ways. + +I strongly recommend you have a good grasp of how the C and C++ +standards require macros to be expanded before diving into this +section, let alone the code!. If you don't have a clear mental +picture of how things like nested macro expansion, stringification and +token pasting are supposed to work, damage to your sanity can quickly +result. + +@section Internal representation of macros +@cindex macro representation (internal) + +The preprocessor stores macro expansions in tokenized form. This +saves repeated lexing passes during expansion, at the cost of a small +increase in memory consumption on average. The tokens are stored +contiguously in memory, so a pointer to the first one and a token +count is all you need to get the replacement list of a macro. + +If the macro is a function-like macro the preprocessor also stores its +parameters, in the form of an ordered list of pointers to the hash +table entry of each parameter's identifier. Further, in the macro's +stored expansion each occurrence of a parameter is replaced with a +special token of type @code{CPP_MACRO_ARG}. Each such token holds the +index of the parameter it represents in the parameter list, which +allows rapid replacement of parameters with their arguments during +expansion. Despite this optimization it is still necessary to store +the original parameters to the macro, both for dumping with e.g., +@option{-dD}, and to warn about non-trivial macro redefinitions when +the parameter names have changed. + +@section Macro expansion overview +The preprocessor maintains a @dfn{context stack}, implemented as a +linked list of @code{cpp_context} structures, which together represent +the macro expansion state at any one time. The @code{struct +cpp_reader} member variable @code{context} points to the current top +of this stack. The top normally holds the unexpanded replacement list +of the innermost macro under expansion, except when cpplib is about to +pre-expand an argument, in which case it holds that argument's +unexpanded tokens. + +When there are no macros under expansion, cpplib is in @dfn{base +context}. All contexts other than the base context contain a +contiguous list of tokens delimited by a starting and ending token. +When not in base context, cpplib obtains the next token from the list +of the top context. If there are no tokens left in the list, it pops +that context off the stack, and subsequent ones if necessary, until an +unexhausted context is found or it returns to base context. In base +context, cpplib reads tokens directly from the lexer. + +If it encounters an identifier that is both a macro and enabled for +expansion, cpplib prepares to push a new context for that macro on the +stack by calling the routine @code{enter_macro_context}. When this +routine returns, the new context will contain the unexpanded tokens of +the replacement list of that macro. In the case of function-like +macros, @code{enter_macro_context} also replaces any parameters in the +replacement list, stored as @code{CPP_MACRO_ARG} tokens, with the +appropriate macro argument. If the standard requires that the +parameter be replaced with its expanded argument, the argument will +have been fully macro expanded first. + +@code{enter_macro_context} also handles special macros like +@code{__LINE__}. Although these macros expand to a single token which +cannot contain any further macros, for reasons of token spacing +(@pxref{Token Spacing}) and simplicity of implementation, cpplib +handles these special macros by pushing a context containing just that +one token. + +The final thing that @code{enter_macro_context} does before returning +is to mark the macro disabled for expansion (except for special macros +like @code{__TIME__}). The macro is re-enabled when its context is +later popped from the context stack, as described above. This strict +ordering ensures that a macro is disabled whilst its expansion is +being scanned, but that it is @emph{not} disabled whilst any arguments +to it are being expanded. + +@section Scanning the replacement list for macros to expand +The C standard states that, after any parameters have been replaced +with their possibly-expanded arguments, the replacement list is +scanned for nested macros. Further, any identifiers in the +replacement list that are not expanded during this scan are never +again eligible for expansion in the future, if the reason they were +not expanded is that the macro in question was disabled. + +Clearly this latter condition can only apply to tokens resulting from +argument pre-expansion. Other tokens never have an opportunity to be +re-tested for expansion. It is possible for identifiers that are +function-like macros to not expand initially but to expand during a +later scan. This occurs when the identifier is the last token of an +argument (and therefore originally followed by a comma or a closing +parenthesis in its macro's argument list), and when it replaces its +parameter in the macro's replacement list, the subsequent token +happens to be an opening parenthesis (itself possibly the first token +of an argument). + +It is important to note that when cpplib reads the last token of a +given context, that context still remains on the stack. Only when +looking for the @emph{next} token do we pop it off the stack and drop +to a lower context. This makes backing up by one token easy, but more +importantly ensures that the macro corresponding to the current +context is still disabled when we are considering the last token of +its replacement list for expansion (or indeed expanding it). As an +example, which illustrates many of the points above, consider + +@smallexample +#define foo(x) bar x +foo(foo) (2) +@end smallexample + +@noindent which fully expands to @samp{bar foo (2)}. During pre-expansion +of the argument, @samp{foo} does not expand even though the macro is +enabled, since it has no following parenthesis [pre-expansion of an +argument only uses tokens from that argument; it cannot take tokens +from whatever follows the macro invocation]. This still leaves the +argument token @samp{foo} eligible for future expansion. Then, when +re-scanning after argument replacement, the token @samp{foo} is +rejected for expansion, and marked ineligible for future expansion, +since the macro is now disabled. It is disabled because the +replacement list @samp{bar foo} of the macro is still on the context +stack. + +If instead the algorithm looked for an opening parenthesis first and +then tested whether the macro were disabled it would be subtly wrong. +In the example above, the replacement list of @samp{foo} would be +popped in the process of finding the parenthesis, re-enabling +@samp{foo} and expanding it a second time. + +@section Looking for a function-like macro's opening parenthesis +Function-like macros only expand when immediately followed by a +parenthesis. To do this cpplib needs to temporarily disable macros +and read the next token. Unfortunately, because of spacing issues +(@pxref{Token Spacing}), there can be fake padding tokens in-between, +and if the next real token is not a parenthesis cpplib needs to be +able to back up that one token as well as retain the information in +any intervening padding tokens. + +Backing up more than one token when macros are involved is not +permitted by cpplib, because in general it might involve issues like +restoring popped contexts onto the context stack, which are too hard. +Instead, searching for the parenthesis is handled by a special +function, @code{funlike_invocation_p}, which remembers padding +information as it reads tokens. If the next real token is not an +opening parenthesis, it backs up that one token, and then pushes an +extra context just containing the padding information if necessary. + +@section Marking tokens ineligible for future expansion +As discussed above, cpplib needs a way of marking tokens as +unexpandable. Since the tokens cpplib handles are read-only once they +have been lexed, it instead makes a copy of the token and adds the +flag @code{NO_EXPAND} to the copy. + +For efficiency and to simplify memory management by avoiding having to +remember to free these tokens, they are allocated as temporary tokens +from the lexer's current token run (@pxref{Lexing a line}) using the +function @code{_cpp_temp_token}. The tokens are then re-used once the +current line of tokens has been read in. + +This might sound unsafe. However, tokens runs are not re-used at the +end of a line if it happens to be in the middle of a macro argument +list, and cpplib only wants to back-up more than one lexer token in +situations where no macro expansion is involved, so the optimization +is safe. + +@node Token Spacing +@unnumbered Token Spacing +@cindex paste avoidance +@cindex spacing +@cindex token spacing + +First, consider an issue that only concerns the stand-alone +preprocessor: there needs to be a guarantee that re-reading its preprocessed +output results in an identical token stream. Without taking special +measures, this might not be the case because of macro substitution. +For example: + +@smallexample +#define PLUS + +#define EMPTY +#define f(x) =x= ++PLUS -EMPTY- PLUS+ f(=) + @expansion{} + + - - + + = = = +@emph{not} + @expansion{} ++ -- ++ === +@end smallexample + +One solution would be to simply insert a space between all adjacent +tokens. However, we would like to keep space insertion to a minimum, +both for aesthetic reasons and because it causes problems for people who +still try to abuse the preprocessor for things like Fortran source and +Makefiles. + +For now, just notice that when tokens are added (or removed, as shown by +the @code{EMPTY} example) from the original lexed token stream, we need +to check for accidental token pasting. We call this @dfn{paste +avoidance}. Token addition and removal can only occur because of macro +expansion, but accidental pasting can occur in many places: both before +and after each macro replacement, each argument replacement, and +additionally each token created by the @samp{#} and @samp{##} operators. + +Look at how the preprocessor gets whitespace output correct +normally. The @code{cpp_token} structure contains a flags byte, and one +of those flags is @code{PREV_WHITE}. This is flagged by the lexer, and +indicates that the token was preceded by whitespace of some form other +than a new line. The stand-alone preprocessor can use this flag to +decide whether to insert a space between tokens in the output. + +Now consider the result of the following macro expansion: + +@smallexample +#define add(x, y, z) x + y +z; +sum = add (1,2, 3); + @expansion{} sum = 1 + 2 +3; +@end smallexample + +The interesting thing here is that the tokens @samp{1} and @samp{2} are +output with a preceding space, and @samp{3} is output without a +preceding space, but when lexed none of these tokens had that property. +Careful consideration reveals that @samp{1} gets its preceding +whitespace from the space preceding @samp{add} in the macro invocation, +@emph{not} replacement list. @samp{2} gets its whitespace from the +space preceding the parameter @samp{y} in the macro replacement list, +and @samp{3} has no preceding space because parameter @samp{z} has none +in the replacement list. + +Once lexed, tokens are effectively fixed and cannot be altered, since +pointers to them might be held in many places, in particular by +in-progress macro expansions. So instead of modifying the two tokens +above, the preprocessor inserts a special token, which I call a +@dfn{padding token}, into the token stream to indicate that spacing of +the subsequent token is special. The preprocessor inserts padding +tokens in front of every macro expansion and expanded macro argument. +These point to a @dfn{source token} from which the subsequent real token +should inherit its spacing. In the above example, the source tokens are +@samp{add} in the macro invocation, and @samp{y} and @samp{z} in the +macro replacement list, respectively. + +It is quite easy to get multiple padding tokens in a row, for example if +a macro's first replacement token expands straight into another macro. + +@smallexample +#define foo bar +#define bar baz +[foo] + @expansion{} [baz] +@end smallexample + +Here, two padding tokens are generated with sources the @samp{foo} token +between the brackets, and the @samp{bar} token from foo's replacement +list, respectively. Clearly the first padding token is the one to +use, so the output code should contain a rule that the first +padding token in a sequence is the one that matters. + +But what if a macro expansion is left? Adjusting the above +example slightly: + +@smallexample +#define foo bar +#define bar EMPTY baz +#define EMPTY +[foo] EMPTY; + @expansion{} [ baz] ; +@end smallexample + +As shown, now there should be a space before @samp{baz} and the +semicolon in the output. + +The rules we decided above fail for @samp{baz}: we generate three +padding tokens, one per macro invocation, before the token @samp{baz}. +We would then have it take its spacing from the first of these, which +carries source token @samp{foo} with no leading space. + +It is vital that cpplib get spacing correct in these examples since any +of these macro expansions could be stringified, where spacing matters. + +So, this demonstrates that not just entering macro and argument +expansions, but leaving them requires special handling too. I made +cpplib insert a padding token with a @code{NULL} source token when +leaving macro expansions, as well as after each replaced argument in a +macro's replacement list. It also inserts appropriate padding tokens on +either side of tokens created by the @samp{#} and @samp{##} operators. +I expanded the rule so that, if we see a padding token with a +@code{NULL} source token, @emph{and} that source token has no leading +space, then we behave as if we have seen no padding tokens at all. A +quick check shows this rule will then get the above example correct as +well. + +Now a relationship with paste avoidance is apparent: we have to be +careful about paste avoidance in exactly the same locations we have +padding tokens in order to get white space correct. This makes +implementation of paste avoidance easy: wherever the stand-alone +preprocessor is fixing up spacing because of padding tokens, and it +turns out that no space is needed, it has to take the extra step to +check that a space is not needed after all to avoid an accidental paste. +The function @code{cpp_avoid_paste} advises whether a space is required +between two consecutive tokens. To avoid excessive spacing, it tries +hard to only require a space if one is likely to be necessary, but for +reasons of efficiency it is slightly conservative and might recommend a +space where one is not strictly needed. + +@node Line Numbering +@unnumbered Line numbering +@cindex line numbers + +@section Just which line number anyway? + +There are three reasonable requirements a cpplib client might have for +the line number of a token passed to it: + +@itemize @bullet +@item +The source line it was lexed on. +@item +The line it is output on. This can be different to the line it was +lexed on if, for example, there are intervening escaped newlines or +C-style comments. For example: + +@smallexample +foo /* @r{A long +comment} */ bar \ +baz +@result{} +foo bar baz +@end smallexample + +@item +If the token results from a macro expansion, the line of the macro name, +or possibly the line of the closing parenthesis in the case of +function-like macro expansion. +@end itemize + +The @code{cpp_token} structure contains @code{line} and @code{col} +members. The lexer fills these in with the line and column of the first +character of the token. Consequently, but maybe unexpectedly, a token +from the replacement list of a macro expansion carries the location of +the token within the @code{#define} directive, because cpplib expands a +macro by returning pointers to the tokens in its replacement list. The +current implementation of cpplib assigns tokens created from built-in +macros and the @samp{#} and @samp{##} operators the location of the most +recently lexed token. This is a because they are allocated from the +lexer's token runs, and because of the way the diagnostic routines infer +the appropriate location to report. + +The diagnostic routines in cpplib display the location of the most +recently @emph{lexed} token, unless they are passed a specific line and +column to report. For diagnostics regarding tokens that arise from +macro expansions, it might also be helpful for the user to see the +original location in the macro definition that the token came from. +Since that is exactly the information each token carries, such an +enhancement could be made relatively easily in future. + +The stand-alone preprocessor faces a similar problem when determining +the correct line to output the token on: the position attached to a +token is fairly useless if the token came from a macro expansion. All +tokens on a logical line should be output on its first physical line, so +the token's reported location is also wrong if it is part of a physical +line other than the first. + +To solve these issues, cpplib provides a callback that is generated +whenever it lexes a preprocessing token that starts a new logical line +other than a directive. It passes this token (which may be a +@code{CPP_EOF} token indicating the end of the translation unit) to the +callback routine, which can then use the line and column of this token +to produce correct output. + +@section Representation of line numbers + +As mentioned above, cpplib stores with each token the line number that +it was lexed on. In fact, this number is not the number of the line in +the source file, but instead bears more resemblance to the number of the +line in the translation unit. + +The preprocessor maintains a monotonic increasing line count, which is +incremented at every new line character (and also at the end of any +buffer that does not end in a new line). Since a line number of zero is +useful to indicate certain special states and conditions, this variable +starts counting from one. + +This variable therefore uniquely enumerates each line in the translation +unit. With some simple infrastructure, it is straight forward to map +from this to the original source file and line number pair, saving space +whenever line number information needs to be saved. The code the +implements this mapping lies in the files @file{line-map.c} and +@file{line-map.h}. + +Command-line macros and assertions are implemented by pushing a buffer +containing the right hand side of an equivalent @code{#define} or +@code{#assert} directive. Some built-in macros are handled similarly. +Since these are all processed before the first line of the main input +file, it will typically have an assigned line closer to twenty than to +one. + +@node Guard Macros +@unnumbered The Multiple-Include Optimization +@cindex guard macros +@cindex controlling macros +@cindex multiple-include optimization + +Header files are often of the form + +@smallexample +#ifndef FOO +#define FOO +@dots{} +#endif +@end smallexample + +@noindent +to prevent the compiler from processing them more than once. The +preprocessor notices such header files, so that if the header file +appears in a subsequent @code{#include} directive and @code{FOO} is +defined, then it is ignored and it doesn't preprocess or even re-open +the file a second time. This is referred to as the @dfn{multiple +include optimization}. + +Under what circumstances is such an optimization valid? If the file +were included a second time, it can only be optimized away if that +inclusion would result in no tokens to return, and no relevant +directives to process. Therefore the current implementation imposes +requirements and makes some allowances as follows: + +@enumerate +@item +There must be no tokens outside the controlling @code{#if}-@code{#endif} +pair, but whitespace and comments are permitted. + +@item +There must be no directives outside the controlling directive pair, but +the @dfn{null directive} (a line containing nothing other than a single +@samp{#} and possibly whitespace) is permitted. + +@item +The opening directive must be of the form + +@smallexample +#ifndef FOO +@end smallexample + +or + +@smallexample +#if !defined FOO [equivalently, #if !defined(FOO)] +@end smallexample + +@item +In the second form above, the tokens forming the @code{#if} expression +must have come directly from the source file---no macro expansion must +have been involved. This is because macro definitions can change, and +tracking whether or not a relevant change has been made is not worth the +implementation cost. + +@item +There can be no @code{#else} or @code{#elif} directives at the outer +conditional block level, because they would probably contain something +of interest to a subsequent pass. +@end enumerate + +First, when pushing a new file on the buffer stack, +@code{_stack_include_file} sets the controlling macro @code{mi_cmacro} to +@code{NULL}, and sets @code{mi_valid} to @code{true}. This indicates +that the preprocessor has not yet encountered anything that would +invalidate the multiple-include optimization. As described in the next +few paragraphs, these two variables having these values effectively +indicates top-of-file. + +When about to return a token that is not part of a directive, +@code{_cpp_lex_token} sets @code{mi_valid} to @code{false}. This +enforces the constraint that tokens outside the controlling conditional +block invalidate the optimization. + +The @code{do_if}, when appropriate, and @code{do_ifndef} directive +handlers pass the controlling macro to the function +@code{push_conditional}. cpplib maintains a stack of nested conditional +blocks, and after processing every opening conditional this function +pushes an @code{if_stack} structure onto the stack. In this structure +it records the controlling macro for the block, provided there is one +and we're at top-of-file (as described above). If an @code{#elif} or +@code{#else} directive is encountered, the controlling macro for that +block is cleared to @code{NULL}. Otherwise, it survives until the +@code{#endif} closing the block, upon which @code{do_endif} sets +@code{mi_valid} to true and stores the controlling macro in +@code{mi_cmacro}. + +@code{_cpp_handle_directive} clears @code{mi_valid} when processing any +directive other than an opening conditional and the null directive. +With this, and requiring top-of-file to record a controlling macro, and +no @code{#else} or @code{#elif} for it to survive and be copied to +@code{mi_cmacro} by @code{do_endif}, we have enforced the absence of +directives outside the main conditional block for the optimization to be +on. + +Note that whilst we are inside the conditional block, @code{mi_valid} is +likely to be reset to @code{false}, but this does not matter since +the closing @code{#endif} restores it to @code{true} if appropriate. + +Finally, since @code{_cpp_lex_direct} pops the file off the buffer stack +at @code{EOF} without returning a token, if the @code{#endif} directive +was not followed by any tokens, @code{mi_valid} is @code{true} and +@code{_cpp_pop_file_buffer} remembers the controlling macro associated +with the file. Subsequent calls to @code{stack_include_file} result in +no buffer being pushed if the controlling macro is defined, effecting +the optimization. + +A quick word on how we handle the + +@smallexample +#if !defined FOO +@end smallexample + +@noindent +case. @code{_cpp_parse_expr} and @code{parse_defined} take steps to see +whether the three stages @samp{!}, @samp{defined-expression} and +@samp{end-of-directive} occur in order in a @code{#if} expression. If +so, they return the guard macro to @code{do_if} in the variable +@code{mi_ind_cmacro}, and otherwise set it to @code{NULL}. +@code{enter_macro_context} sets @code{mi_valid} to false, so if a macro +was expanded whilst parsing any part of the expression, then the +top-of-file test in @code{push_conditional} fails and the optimization +is turned off. + +@node Files +@unnumbered File Handling +@cindex files + +Fairly obviously, the file handling code of cpplib resides in the file +@file{files.c}. It takes care of the details of file searching, +opening, reading and caching, for both the main source file and all the +headers it recursively includes. + +The basic strategy is to minimize the number of system calls. On many +systems, the basic @code{open ()} and @code{fstat ()} system calls can +be quite expensive. For every @code{#include}-d file, we need to try +all the directories in the search path until we find a match. Some +projects, such as glibc, pass twenty or thirty include paths on the +command line, so this can rapidly become time consuming. + +For a header file we have not encountered before we have little choice +but to do this. However, it is often the case that the same headers are +repeatedly included, and in these cases we try to avoid repeating the +filesystem queries whilst searching for the correct file. + +For each file we try to open, we store the constructed path in a splay +tree. This path first undergoes simplification by the function +@code{_cpp_simplify_pathname}. For example, +@file{/usr/include/bits/../foo.h} is simplified to +@file{/usr/include/foo.h} before we enter it in the splay tree and try +to @code{open ()} the file. CPP will then find subsequent uses of +@file{foo.h}, even as @file{/usr/include/foo.h}, in the splay tree and +save system calls. + +Further, it is likely the file contents have also been cached, saving a +@code{read ()} system call. We don't bother caching the contents of +header files that are re-inclusion protected, and whose re-inclusion +macro is defined when we leave the header file for the first time. If +the host supports it, we try to map suitably large files into memory, +rather than reading them in directly. + +The include paths are internally stored on a null-terminated +singly-linked list, starting with the @code{"header.h"} directory search +chain, which then links into the @code{<header.h>} directory chain. + +Files included with the @code{<foo.h>} syntax start the lookup directly +in the second half of this chain. However, files included with the +@code{"foo.h"} syntax start at the beginning of the chain, but with one +extra directory prepended. This is the directory of the current file; +the one containing the @code{#include} directive. Prepending this +directory on a per-file basis is handled by the function +@code{search_from}. + +Note that a header included with a directory component, such as +@code{#include "mydir/foo.h"} and opened as +@file{/usr/local/include/mydir/foo.h}, will have the complete path minus +the basename @samp{foo.h} as the current directory. + +Enough information is stored in the splay tree that CPP can immediately +tell whether it can skip the header file because of the multiple include +optimization, whether the file didn't exist or couldn't be opened for +some reason, or whether the header was flagged not to be re-used, as it +is with the obsolete @code{#import} directive. + +For the benefit of MS-DOS filesystems with an 8.3 filename limitation, +CPP offers the ability to treat various include file names as aliases +for the real header files with shorter names. The map from one to the +other is found in a special file called @samp{header.gcc}, stored in the +command line (or system) include directories to which the mapping +applies. This may be higher up the directory tree than the full path to +the file minus the base name. + +@node Concept Index +@unnumbered Concept Index +@printindex cp + +@bye diff --git a/gcc-4.2.1-5666.3/gcc/doc/cppopts.texi b/gcc-4.2.1-5666.3/gcc/doc/cppopts.texi new file mode 100644 index 000000000..06c095d15 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/cppopts.texi @@ -0,0 +1,765 @@ +@c Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 +@c Free Software Foundation, Inc. +@c This is part of the CPP and GCC manuals. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Options affecting the preprocessor +@c --------------------------------------------------------------------- + +@c If this file is included with the flag ``cppmanual'' set, it is +@c formatted for inclusion in the CPP manual; otherwise the main GCC manual. + +@table @gcctabopt +@item -D @var{name} +@opindex D +Predefine @var{name} as a macro, with definition @code{1}. + +@item -D @var{name}=@var{definition} +The contents of @var{definition} are tokenized and processed as if +they appeared during translation phase three in a @samp{#define} +directive. In particular, the definition will be truncated by +embedded newline characters. + +If you are invoking the preprocessor from a shell or shell-like +program you may need to use the shell's quoting syntax to protect +characters such as spaces that have a meaning in the shell syntax. + +If you wish to define a function-like macro on the command line, write +its argument list with surrounding parentheses before the equals sign +(if any). Parentheses are meaningful to most shells, so you will need +to quote the option. With @command{sh} and @command{csh}, +@option{-D'@var{name}(@var{args@dots{}})=@var{definition}'} works. + +@option{-D} and @option{-U} options are processed in the order they +are given on the command line. All @option{-imacros @var{file}} and +@option{-include @var{file}} options are processed after all +@option{-D} and @option{-U} options. + +@item -U @var{name} +@opindex U +Cancel any previous definition of @var{name}, either built in or +provided with a @option{-D} option. + +@item -undef +@opindex undef +Do not predefine any system-specific or GCC-specific macros. The +standard predefined macros remain defined. +@ifset cppmanual +@xref{Standard Predefined Macros}. +@end ifset + +@item -I @var{dir} +@opindex I +Add the directory @var{dir} to the list of directories to be searched +for header files. +@ifset cppmanual +@xref{Search Path}. +@end ifset +Directories named by @option{-I} are searched before the standard +system include directories. If the directory @var{dir} is a standard +system include directory, the option is ignored to ensure that the +default search order for system directories and the special treatment +of system headers are not defeated +@ifset cppmanual +(@pxref{System Headers}) +@end ifset +. + +@item -o @var{file} +@opindex o +Write output to @var{file}. This is the same as specifying @var{file} +as the second non-option argument to @command{cpp}. @command{gcc} has a +different interpretation of a second non-option argument, so you must +use @option{-o} to specify the output file. + +@item -Wall +@opindex Wall +Turns on all optional warnings which are desirable for normal code. +At present this is @option{-Wcomment}, @option{-Wtrigraphs}, +@option{-Wmultichar} and a warning about integer promotion causing a +change of sign in @code{#if} expressions. Note that many of the +preprocessor's warnings are on by default and have no options to +control them. + +@item -Wcomment +@itemx -Wcomments +@opindex Wcomment +@opindex Wcomments +Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*} +comment, or whenever a backslash-newline appears in a @samp{//} comment. +(Both forms have the same effect.) + +@item -Wtrigraphs +@opindex Wtrigraphs +@anchor{Wtrigraphs} +Most trigraphs in comments cannot affect the meaning of the program. +However, a trigraph that would form an escaped newline (@samp{??/} at +the end of a line) can, by changing where the comment begins or ends. +Therefore, only trigraphs that would form escaped newlines produce +warnings inside a comment. + +This option is implied by @option{-Wall}. If @option{-Wall} is not +given, this option is still enabled unless trigraphs are enabled. To +get trigraph conversion without warnings, but get the other +@option{-Wall} warnings, use @samp{-trigraphs -Wall -Wno-trigraphs}. + +@item -Wtraditional +@opindex Wtraditional +Warn about certain constructs that behave differently in traditional and +ISO C@. Also warn about ISO C constructs that have no traditional C +equivalent, and problematic constructs which should be avoided. +@ifset cppmanual +@xref{Traditional Mode}. +@end ifset + +@item -Wimport +@opindex Wimport +Warn the first time @samp{#import} is used. + +@item -Wundef +@opindex Wundef +Warn whenever an identifier which is not a macro is encountered in an +@samp{#if} directive, outside of @samp{defined}. Such identifiers are +replaced with zero. + +@item -Wunused-macros +@opindex Wunused-macros +Warn about macros defined in the main file that are unused. A macro +is @dfn{used} if it is expanded or tested for existence at least once. +The preprocessor will also warn if the macro has not been used at the +time it is redefined or undefined. + +Built-in macros, macros defined on the command line, and macros +defined in include files are not warned about. + +@emph{Note:} If a macro is actually used, but only used in skipped +conditional blocks, then CPP will report it as unused. To avoid the +warning in such a case, you might improve the scope of the macro's +definition by, for example, moving it into the first skipped block. +Alternatively, you could provide a dummy use with something like: + +@smallexample +#if defined the_macro_causing_the_warning +#endif +@end smallexample + +@item -Wendif-labels +@opindex Wendif-labels +Warn whenever an @samp{#else} or an @samp{#endif} are followed by text. +This usually happens in code of the form + +@smallexample +#if FOO +@dots{} +#else FOO +@dots{} +#endif FOO +@end smallexample + +@noindent +The second and third @code{FOO} should be in comments, but often are not +in older programs. This warning is on by default. + +@item -Werror +@opindex Werror +Make all warnings into hard errors. Source code which triggers warnings +will be rejected. + +@item -Wsystem-headers +@opindex Wsystem-headers +Issue warnings for code in system headers. These are normally unhelpful +in finding bugs in your own code, therefore suppressed. If you are +responsible for the system library, you may want to see them. + +@item -w +@opindex w +Suppress all warnings, including those which GNU CPP issues by default. + +@item -pedantic +@opindex pedantic +Issue all the mandatory diagnostics listed in the C standard. Some of +them are left out by default, since they trigger frequently on harmless +code. + +@item -pedantic-errors +@opindex pedantic-errors +Issue all the mandatory diagnostics, and make all mandatory diagnostics +into errors. This includes mandatory diagnostics that GCC issues +without @samp{-pedantic} but treats as warnings. + +@item -M +@opindex M +@cindex make +@cindex dependencies, make +Instead of outputting the result of preprocessing, output a rule +suitable for @command{make} describing the dependencies of the main +source file. The preprocessor outputs one @command{make} rule containing +the object file name for that source file, a colon, and the names of all +the included files, including those coming from @option{-include} or +@option{-imacros} command line options. + +Unless specified explicitly (with @option{-MT} or @option{-MQ}), the +object file name consists of the basename of the source file with any +suffix replaced with object file suffix. If there are many included +files then the rule is split into several lines using @samp{\}-newline. +The rule has no commands. + +This option does not suppress the preprocessor's debug output, such as +@option{-dM}. To avoid mixing such debug output with the dependency +rules you should explicitly specify the dependency output file with +@option{-MF}, or use an environment variable like +@env{DEPENDENCIES_OUTPUT} (@pxref{Environment Variables}). Debug output +will still be sent to the regular output stream as normal. + +Passing @option{-M} to the driver implies @option{-E}, and suppresses +warnings with an implicit @option{-w}. + +@item -MM +@opindex MM +Like @option{-M} but do not mention header files that are found in +system header directories, nor header files that are included, +directly or indirectly, from such a header. + +This implies that the choice of angle brackets or double quotes in an +@samp{#include} directive does not in itself determine whether that +header will appear in @option{-MM} dependency output. This is a +slight change in semantics from GCC versions 3.0 and earlier. + +@anchor{dashMF} +@item -MF @var{file} +@opindex MF +When used with @option{-M} or @option{-MM}, specifies a +file to write the dependencies to. If no @option{-MF} switch is given +the preprocessor sends the rules to the same place it would have sent +preprocessed output. + +When used with the driver options @option{-MD} or @option{-MMD}, +@option{-MF} overrides the default dependency output file. + +@c APPLE LOCAL begin -dependency-file +@item -dependency-file +@opindex dependency-file @var{name} +Like @option{-MF}. (APPLE ONLY) +@c APPLE LOCAL end -dependency-file + +@item -MG +@opindex MG +In conjunction with an option such as @option{-M} requesting +dependency generation, @option{-MG} assumes missing header files are +generated files and adds them to the dependency list without raising +an error. The dependency filename is taken directly from the +@code{#include} directive without prepending any path. @option{-MG} +also suppresses preprocessed output, as a missing header file renders +this useless. + +This feature is used in automatic updating of makefiles. + +@item -MP +@opindex MP +This option instructs CPP to add a phony target for each dependency +other than the main file, causing each to depend on nothing. These +dummy rules work around errors @command{make} gives if you remove header +files without updating the @file{Makefile} to match. + +This is typical output: + +@smallexample +test.o: test.c test.h + +test.h: +@end smallexample + +@item -MT @var{target} +@opindex MT + +Change the target of the rule emitted by dependency generation. By +default CPP takes the name of the main input file, including any path, +deletes any file suffix such as @samp{.c}, and appends the platform's +usual object suffix. The result is the target. + +An @option{-MT} option will set the target to be exactly the string you +specify. If you want multiple targets, you can specify them as a single +argument to @option{-MT}, or use multiple @option{-MT} options. + +For example, @option{@w{-MT '$(objpfx)foo.o'}} might give + +@smallexample +$(objpfx)foo.o: foo.c +@end smallexample + +@item -MQ @var{target} +@opindex MQ + +Same as @option{-MT}, but it quotes any characters which are special to +Make. @option{@w{-MQ '$(objpfx)foo.o'}} gives + +@smallexample +$$(objpfx)foo.o: foo.c +@end smallexample + +The default target is automatically quoted, as if it were given with +@option{-MQ}. + +@item -MD +@opindex MD +@option{-MD} is equivalent to @option{-M -MF @var{file}}, except that +@option{-E} is not implied. The driver determines @var{file} based on +whether an @option{-o} option is given. If it is, the driver uses its +argument but with a suffix of @file{.d}, otherwise it take the +basename of the input file and applies a @file{.d} suffix. + +If @option{-MD} is used in conjunction with @option{-E}, any +@option{-o} switch is understood to specify the dependency output file +(@pxref{dashMF,,-MF}), but if used without @option{-E}, each @option{-o} +is understood to specify a target object file. + +Since @option{-E} is not implied, @option{-MD} can be used to generate +a dependency output file as a side-effect of the compilation process. + +@item -MMD +@opindex MMD +Like @option{-MD} except mention only user header files, not system +header files. + +@ifclear cppmanual +@item -fpch-deps +@opindex fpch-deps +When using precompiled headers (@pxref{Precompiled Headers}), this flag +will cause the dependency-output flags to also list the files from the +precompiled header's dependencies. If not specified only the +precompiled header would be listed and not the files that were used to +create it because those files are not consulted when a precompiled +header is used. + +@item -fpch-preprocess +@opindex fpch-preprocess +This option allows use of a precompiled header (@pxref{Precompiled +Headers}) together with @option{-E}. It inserts a special @code{#pragma}, +@code{#pragma GCC pch_preprocess "<filename>"} in the output to mark +the place where the precompiled header was found, and its filename. When +@option{-fpreprocessed} is in use, GCC recognizes this @code{#pragma} and +loads the PCH@. + +This option is off by default, because the resulting preprocessed output +is only really suitable as input to GCC@. It is switched on by +@option{-save-temps}. + +You should not write this @code{#pragma} in your own code, but it is +safe to edit the filename if the PCH file is available in a different +location. The filename may be absolute or it may be relative to GCC's +current directory. + +@end ifclear +@item -x c +@itemx -x c++ +@itemx -x objective-c +@c APPLE LOCAL Objective-C++ +@itemx -x objective-c++ +@itemx -x assembler-with-cpp +@opindex x +@c APPLE LOCAL Objective-C++ +Specify the source language: C, C++, Objective-C, Objective-C++, or assembly. This has +nothing to do with standards conformance or extensions; it merely +selects which base syntax to expect. If you give none of these options, +cpp will deduce the language from the extension of the source file: +@c APPLE LOCAL Objective-C++ +@samp{.c}, @samp{.cc}, @samp{.m}, @samp{.mm}, or @samp{.S}. Some other common +extensions for C++ and assembly are also recognized. If cpp does not +recognize the extension, it will treat the file as C; this is the most +generic mode. + +@emph{Note:} Previous versions of cpp accepted a @option{-lang} option +which selected both the language and the standards conformance level. +This option has been removed, because it conflicts with the @option{-l} +option. + +@item -std=@var{standard} +@itemx -ansi +@opindex ansi +@opindex std= +Specify the standard to which the code should conform. Currently CPP +knows about C and C++ standards; others may be added in the future. + +@var{standard} +may be one of: +@table @code +@item iso9899:1990 +@itemx c89 +The ISO C standard from 1990. @samp{c89} is the customary shorthand for +this version of the standard. + +The @option{-ansi} option is equivalent to @option{-std=c89}. + +@item iso9899:199409 +The 1990 C standard, as amended in 1994. + +@item iso9899:1999 +@itemx c99 +@itemx iso9899:199x +@itemx c9x +The revised ISO C standard, published in December 1999. Before +publication, this was known as C9X@. + +@item gnu89 +The 1990 C standard plus GNU extensions. This is the default. + +@item gnu99 +@itemx gnu9x +The 1999 C standard plus GNU extensions. + +@item c++98 +The 1998 ISO C++ standard plus amendments. + +@item gnu++98 +The same as @option{-std=c++98} plus GNU extensions. This is the +default for C++ code. +@end table + +@item -I- +@opindex I- +Split the include path. Any directories specified with @option{-I} +options before @option{-I-} are searched only for headers requested with +@code{@w{#include "@var{file}"}}; they are not searched for +@code{@w{#include <@var{file}>}}. If additional directories are +specified with @option{-I} options after the @option{-I-}, those +directories are searched for all @samp{#include} directives. + +In addition, @option{-I-} inhibits the use of the directory of the current +file directory as the first search directory for @code{@w{#include +"@var{file}"}}. +@ifset cppmanual +@xref{Search Path}. +@end ifset +This option has been deprecated. + +@item -nostdinc +@opindex nostdinc +Do not search the standard system directories for header files. +Only the directories you have specified with @option{-I} options +(and the directory of the current file, if appropriate) are searched. + +@item -nostdinc++ +@opindex nostdinc++ +Do not search for header files in the C++-specific standard directories, +but do still search the other standard directories. (This option is +used when building the C++ library.) + +@item -include @var{file} +@opindex include +Process @var{file} as if @code{#include "file"} appeared as the first +line of the primary source file. However, the first directory searched +for @var{file} is the preprocessor's working directory @emph{instead of} +the directory containing the main source file. If not found there, it +is searched for in the remainder of the @code{#include "@dots{}"} search +chain as normal. + +If multiple @option{-include} options are given, the files are included +in the order they appear on the command line. + +@item -imacros @var{file} +@opindex imacros +Exactly like @option{-include}, except that any output produced by +scanning @var{file} is thrown away. Macros it defines remain defined. +This allows you to acquire all the macros from a header without also +processing its declarations. + +All files specified by @option{-imacros} are processed before all files +specified by @option{-include}. + +@item -idirafter @var{dir} +@opindex idirafter +Search @var{dir} for header files, but do it @emph{after} all +directories specified with @option{-I} and the standard system directories +have been exhausted. @var{dir} is treated as a system include directory. + +@item -iprefix @var{prefix} +@opindex iprefix +Specify @var{prefix} as the prefix for subsequent @option{-iwithprefix} +options. If the prefix represents a directory, you should include the +final @samp{/}. + +@item -iwithprefix @var{dir} +@itemx -iwithprefixbefore @var{dir} +@opindex iwithprefix +@opindex iwithprefixbefore +Append @var{dir} to the prefix specified previously with +@option{-iprefix}, and add the resulting directory to the include search +path. @option{-iwithprefixbefore} puts it in the same place @option{-I} +would; @option{-iwithprefix} puts it where @option{-idirafter} would. + +@item -isysroot @var{dir} +@opindex isysroot +This option is like the @option{--sysroot} option, but applies only to +header files, except for Apple's version of GCC, where it applies to +both header files and libraries and effectively replaces the +@option{--sysroot} option. +See the @option{--sysroot} option for more information. + +@item -imultilib @var{dir} +@opindex imultilib +Use @var{dir} as a subdirectory of the directory containing +target-specific C++ headers. + +@item -isystem @var{dir} +@opindex isystem +Search @var{dir} for header files, after all directories specified by +@option{-I} but before the standard system directories. Mark it +as a system directory, so that it gets the same special treatment as +is applied to the standard system directories. +@ifset cppmanual +@xref{System Headers}. +@end ifset + +@item -iquote @var{dir} +@opindex iquote +Search @var{dir} only for header files requested with +@code{@w{#include "@var{file}"}}; they are not searched for +@code{@w{#include <@var{file}>}}, before all directories specified by +@option{-I} and before the standard system directories. +@ifset cppmanual +@xref{Search Path}. +@end ifset + +@item -fdollars-in-identifiers +@opindex fdollars-in-identifiers +@anchor{fdollars-in-identifiers} +Accept @samp{$} in identifiers. +@ifset cppmanual + @xref{Identifier characters}. +@end ifset + +@item -fextended-identifiers +@opindex fextended-identifiers +Accept universal character names in identifiers. This option is +experimental; in a future version of GCC, it will be enabled by +default for C99 and C++. + +@item -fpreprocessed +@opindex fpreprocessed +Indicate to the preprocessor that the input file has already been +preprocessed. This suppresses things like macro expansion, trigraph +conversion, escaped newline splicing, and processing of most directives. +The preprocessor still recognizes and removes comments, so that you can +pass a file preprocessed with @option{-C} to the compiler without +problems. In this mode the integrated preprocessor is little more than +a tokenizer for the front ends. + +@option{-fpreprocessed} is implicit if the input file has one of the +extensions @samp{.i}, @samp{.ii} or @samp{.mi}. These are the +extensions that GCC uses for preprocessed files created by +@option{-save-temps}. + +@item -ftabstop=@var{width} +@opindex ftabstop +Set the distance between tab stops. This helps the preprocessor report +correct column numbers in warnings or errors, even if tabs appear on the +line. If the value is less than 1 or greater than 100, the option is +ignored. The default is 8. + +@item -fexec-charset=@var{charset} +@opindex fexec-charset +@cindex character set, execution +Set the execution character set, used for string and character +constants. The default is UTF-8. @var{charset} can be any encoding +supported by the system's @code{iconv} library routine. + +@item -fwide-exec-charset=@var{charset} +@opindex fwide-exec-charset +@cindex character set, wide execution +Set the wide execution character set, used for wide string and +character constants. The default is UTF-32 or UTF-16, whichever +corresponds to the width of @code{wchar_t}. As with +@option{-fexec-charset}, @var{charset} can be any encoding supported +by the system's @code{iconv} library routine; however, you will have +problems with encodings that do not fit exactly in @code{wchar_t}. + +@item -finput-charset=@var{charset} +@opindex finput-charset +@cindex character set, input +Set the input character set, used for translation from the character +set of the input file to the source character set used by GCC@. If the +locale does not specify, or GCC cannot get this information from the +locale, the default is UTF-8. This can be overridden by either the locale +or this command line option. Currently the command line option takes +precedence if there's a conflict. @var{charset} can be any encoding +supported by the system's @code{iconv} library routine. + +@item -fworking-directory +@opindex fworking-directory +@opindex fno-working-directory +Enable generation of linemarkers in the preprocessor output that will +let the compiler know the current working directory at the time of +preprocessing. When this option is enabled, the preprocessor will +emit, after the initial linemarker, a second linemarker with the +current working directory followed by two slashes. GCC will use this +directory, when it's present in the preprocessed input, as the +directory emitted as the current working directory in some debugging +information formats. This option is implicitly enabled if debugging +information is enabled, but this can be inhibited with the negated +form @option{-fno-working-directory}. If the @option{-P} flag is +present in the command line, this option has no effect, since no +@code{#line} directives are emitted whatsoever. + +@item -fno-show-column +@opindex fno-show-column +Do not print column numbers in diagnostics. This may be necessary if +diagnostics are being scanned by a program that does not understand the +column numbers, such as @command{dejagnu}. + +@item -A @var{predicate}=@var{answer} +@opindex A +Make an assertion with the predicate @var{predicate} and answer +@var{answer}. This form is preferred to the older form @option{-A +@var{predicate}(@var{answer})}, which is still supported, because +it does not use shell special characters. +@ifset cppmanual +@xref{Assertions}. +@end ifset + +@item -A -@var{predicate}=@var{answer} +Cancel an assertion with the predicate @var{predicate} and answer +@var{answer}. + +@item -dCHARS +@var{CHARS} is a sequence of one or more of the following characters, +and must not be preceded by a space. Other characters are interpreted +by the compiler proper, or reserved for future versions of GCC, and so +are silently ignored. If you specify characters whose behavior +conflicts, the result is undefined. + +@table @samp +@item M +@opindex dM +Instead of the normal output, generate a list of @samp{#define} +directives for all the macros defined during the execution of the +preprocessor, including predefined macros. This gives you a way of +finding out what is predefined in your version of the preprocessor. +Assuming you have no file @file{foo.h}, the command + +@smallexample +touch foo.h; cpp -dM foo.h +@end smallexample + +@noindent +will show all the predefined macros. + +@c APPLE LOCAL begin mainline +If you use @option{-dM} without the @option{-E} option, @option{-dM} is +interpreted as a synonym for @option{-fdump-rtl-mach}. +@xref{Debugging Options, , ,gcc}. + +@c APPLE LOCAL end mainline +@item D +@opindex dD +Like @samp{M} except in two respects: it does @emph{not} include the +predefined macros, and it outputs @emph{both} the @samp{#define} +directives and the result of preprocessing. Both kinds of output go to +the standard output file. + +@item N +@opindex dN +Like @samp{D}, but emit only the macro names, not their expansions. + +@item I +@opindex dI +Output @samp{#include} directives in addition to the result of +preprocessing. +@end table + +@item -P +@opindex P +Inhibit generation of linemarkers in the output from the preprocessor. +This might be useful when running the preprocessor on something that is +not C code, and will be sent to a program which might be confused by the +linemarkers. +@ifset cppmanual +@xref{Preprocessor Output}. +@end ifset + +@item -C +@opindex C +Do not discard comments. All comments are passed through to the output +file, except for comments in processed directives, which are deleted +along with the directive. + +You should be prepared for side effects when using @option{-C}; it +causes the preprocessor to treat comments as tokens in their own right. +For example, comments appearing at the start of what would be a +directive line have the effect of turning that line into an ordinary +source line, since the first token on the line is no longer a @samp{#}. + +@item -CC +Do not discard comments, including during macro expansion. This is +like @option{-C}, except that comments contained within macros are +also passed through to the output file where the macro is expanded. + +In addition to the side-effects of the @option{-C} option, the +@option{-CC} option causes all C++-style comments inside a macro +to be converted to C-style comments. This is to prevent later use +of that macro from inadvertently commenting out the remainder of +the source line. + +The @option{-CC} option is generally used to support lint comments. + +@item -traditional-cpp +@opindex traditional-cpp +Try to imitate the behavior of old-fashioned C preprocessors, as +opposed to ISO C preprocessors. +@ifset cppmanual +@xref{Traditional Mode}. +@end ifset + +@item -trigraphs +@opindex trigraphs +Process trigraph sequences. +@ifset cppmanual +@xref{Initial processing}. +@end ifset +@ifclear cppmanual +These are three-character sequences, all starting with @samp{??}, that +are defined by ISO C to stand for single characters. For example, +@samp{??/} stands for @samp{\}, so @samp{'??/n'} is a character +constant for a newline. By default, GCC ignores trigraphs, but in +standard-conforming modes it converts them. See the @option{-std} and +@option{-ansi} options. + +The nine trigraphs and their replacements are + +@smallexample +Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??- +Replacement: [ ] @{ @} # \ ^ | ~ +@end smallexample +@end ifclear + +@item -remap +@opindex remap +Enable special code to work around file systems which only permit very +short file names, such as MS-DOS@. + +@itemx --help +@itemx --target-help +@opindex help +@opindex target-help +Print text describing all the command line options instead of +preprocessing anything. + +@item -v +@opindex v +Verbose mode. Print out GNU CPP's version number at the beginning of +execution, and report the final form of the include path. + +@item -H +@opindex H +Print the name of each header file used, in addition to other normal +activities. Each name is indented to show how deep in the +@samp{#include} stack it is. Precompiled header files are also +printed, even if they are found to be invalid; an invalid precompiled +header file is printed with @samp{...x} and a valid one with @samp{...!} . + +@item -version +@itemx --version +@opindex version +Print out GNU CPP's version number. With one dash, proceed to +preprocess as normal. With two dashes, exit immediately. +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/extend.texi b/gcc-4.2.1-5666.3/gcc/doc/extend.texi new file mode 100644 index 000000000..123b15dab --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/extend.texi @@ -0,0 +1,11636 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, +@c 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. + +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node C Extensions +@chapter Extensions to the C Language Family +@cindex extensions, C language +@cindex C language extensions + +@opindex pedantic +GNU C provides several language features not found in ISO standard C@. +(The @option{-pedantic} option directs GCC to print a warning message if +any of these features is used.) To test for the availability of these +features in conditional compilation, check for a predefined macro +@code{__GNUC__}, which is always defined under GCC@. + +These extensions are available in C and Objective-C@. Most of them are +also available in C++. @xref{C++ Extensions,,Extensions to the +C++ Language}, for extensions that apply @emph{only} to C++. + +Some features that are in ISO C99 but not C89 or C++ are also, as +extensions, accepted by GCC in C89 mode and in C++. + +@menu +* Statement Exprs:: Putting statements and declarations inside expressions. +* Local Labels:: Labels local to a block. +* Labels as Values:: Getting pointers to labels, and computed gotos. +* Nested Functions:: As in Algol and Pascal, lexical scoping of functions. +* Constructing Calls:: Dispatching a call to another function. +* Typeof:: @code{typeof}: referring to the type of an expression. +* Conditionals:: Omitting the middle operand of a @samp{?:} expression. +* Long Long:: Double-word integers---@code{long long int}. +* Complex:: Data types for complex numbers. +* Decimal Float:: Decimal Floating Types. +* Hex Floats:: Hexadecimal floating-point constants. +* Zero Length:: Zero-length arrays. +* Variable Length:: Arrays whose length is computed at run time. +* Empty Structures:: Structures with no members. +* Variadic Macros:: Macros with a variable number of arguments. +* Escaped Newlines:: Slightly looser rules for escaped newlines. +* Subscripting:: Any array can be subscripted, even if not an lvalue. +* Pointer Arith:: Arithmetic on @code{void}-pointers and function pointers. +* Initializers:: Non-constant initializers. +* Compound Literals:: Compound literals give structures, unions + or arrays as values. +* Designated Inits:: Labeling elements of initializers. +* Cast to Union:: Casting to union type from any member of the union. +* Case Ranges:: `case 1 ... 9' and such. +* Mixed Declarations:: Mixing declarations and code. +* Function Attributes:: Declaring that functions have no side effects, + or that they can never return. +* Attribute Syntax:: Formal syntax for attributes. +* Function Prototypes:: Prototype declarations and old-style definitions. +* C++ Comments:: C++ comments are recognized. +* Dollar Signs:: Dollar sign is allowed in identifiers. +* Character Escapes:: @samp{\e} stands for the character @key{ESC}. +@c APPLE LOCAL begin pascal strings +* Pascal Strings:: Constructing string literals with a Pascal-style + length byte. +@c APPLE LOCAL end pascal strings +* Variable Attributes:: Specifying attributes of variables. +* Type Attributes:: Specifying attributes of types. +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +* Label Attributes:: Specifying attributes of labels and statements. +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +* Alignment:: Inquiring about the alignment of a type or variable. +* Inline:: Defining inline functions (as fast as macros). +* Extended Asm:: Assembler instructions with C expressions as operands. + (With them you can define ``built-in'' functions.) +* Constraints:: Constraints for asm operands +* Asm Labels:: Specifying the assembler name to use for a C symbol. +* Explicit Reg Vars:: Defining variables residing in specified registers. +@c APPLE LOCAL CW asm blocks +* Asm Blocks and Functions:: Block and functions of assembly code. +* Alternate Keywords:: @code{__const__}, @code{__asm__}, etc., for header files. +* Incomplete Enums:: @code{enum foo;}, with details to follow. +* Function Names:: Printable strings which are the name of the current + function. +* Return Address:: Getting the return or frame address of a function. +* Vector Extensions:: Using vector instructions through built-in functions. +* Offsetof:: Special syntax for implementing @code{offsetof}. +* Atomic Builtins:: Built-in functions for atomic memory access. +* Object Size Checking:: Built-in functions for limited buffer overflow + checking. +* Other Builtins:: Other built-in functions. +* Target Builtins:: Built-in functions specific to particular targets. +* Target Format Checks:: Format checks specific to particular targets. +* Pragmas:: Pragmas accepted by GCC. +* Unnamed Fields:: Unnamed struct/union fields within structs/unions. +* Thread-Local:: Per-thread variables. +@c APPLE LOCAL blocks 7205047 5811887 +* Blocks:: Anonymous functions (closures). +@end menu + +@node Statement Exprs +@section Statements and Declarations in Expressions +@cindex statements inside expressions +@cindex declarations inside expressions +@cindex expressions containing statements +@cindex macros, statements in expressions + +@c the above section title wrapped and causes an underfull hbox.. i +@c changed it from "within" to "in". --mew 4feb93 +A compound statement enclosed in parentheses may appear as an expression +in GNU C@. This allows you to use loops, switches, and local variables +within an expression. + +Recall that a compound statement is a sequence of statements surrounded +by braces; in this construct, parentheses go around the braces. For +example: + +@smallexample +(@{ int y = foo (); int z; + if (y > 0) z = y; + else z = - y; + z; @}) +@end smallexample + +@noindent +is a valid (though slightly more complex than necessary) expression +for the absolute value of @code{foo ()}. + +The last thing in the compound statement should be an expression +followed by a semicolon; the value of this subexpression serves as the +value of the entire construct. (If you use some other kind of statement +last within the braces, the construct has type @code{void}, and thus +effectively no value.) + +This feature is especially useful in making macro definitions ``safe'' (so +that they evaluate each operand exactly once). For example, the +``maximum'' function is commonly defined as a macro in standard C as +follows: + +@smallexample +#define max(a,b) ((a) > (b) ? (a) : (b)) +@end smallexample + +@noindent +@cindex side effects, macro argument +But this definition computes either @var{a} or @var{b} twice, with bad +results if the operand has side effects. In GNU C, if you know the +type of the operands (here taken as @code{int}), you can define +the macro safely as follows: + +@smallexample +#define maxint(a,b) \ + (@{int _a = (a), _b = (b); _a > _b ? _a : _b; @}) +@end smallexample + +Embedded statements are not allowed in constant expressions, such as +the value of an enumeration constant, the width of a bit-field, or +the initial value of a static variable. + +If you don't know the type of the operand, you can still do this, but you +must use @code{typeof} (@pxref{Typeof}). + +In G++, the result value of a statement expression undergoes array and +function pointer decay, and is returned by value to the enclosing +expression. For instance, if @code{A} is a class, then + +@smallexample + A a; + + (@{a;@}).Foo () +@end smallexample + +@noindent +will construct a temporary @code{A} object to hold the result of the +statement expression, and that will be used to invoke @code{Foo}. +Therefore the @code{this} pointer observed by @code{Foo} will not be the +address of @code{a}. + +Any temporaries created within a statement within a statement expression +will be destroyed at the statement's end. This makes statement +expressions inside macros slightly different from function calls. In +the latter case temporaries introduced during argument evaluation will +be destroyed at the end of the statement that includes the function +call. In the statement expression case they will be destroyed during +the statement expression. For instance, + +@smallexample +#define macro(a) (@{__typeof__(a) b = (a); b + 3; @}) +template<typename T> T function(T a) @{ T b = a; return b + 3; @} + +void foo () +@{ + macro (X ()); + function (X ()); +@} +@end smallexample + +@noindent +will have different places where temporaries are destroyed. For the +@code{macro} case, the temporary @code{X} will be destroyed just after +the initialization of @code{b}. In the @code{function} case that +temporary will be destroyed when the function returns. + +These considerations mean that it is probably a bad idea to use +statement-expressions of this form in header files that are designed to +work with C++. (Note that some versions of the GNU C Library contained +header files using statement-expression that lead to precisely this +bug.) + +Jumping into a statement expression with @code{goto} or using a +@code{switch} statement outside the statement expression with a +@code{case} or @code{default} label inside the statement expression is +not permitted. Jumping into a statement expression with a computed +@code{goto} (@pxref{Labels as Values}) yields undefined behavior. +Jumping out of a statement expression is permitted, but if the +statement expression is part of a larger expression then it is +unspecified which other subexpressions of that expression have been +evaluated except where the language definition requires certain +subexpressions to be evaluated before or after the statement +expression. In any case, as with a function call the evaluation of a +statement expression is not interleaved with the evaluation of other +parts of the containing expression. For example, + +@smallexample + foo (), ((@{ bar1 (); goto a; 0; @}) + bar2 ()), baz(); +@end smallexample + +@noindent +will call @code{foo} and @code{bar1} and will not call @code{baz} but +may or may not call @code{bar2}. If @code{bar2} is called, it will be +called after @code{foo} and before @code{bar1} + +@node Local Labels +@section Locally Declared Labels +@cindex local labels +@cindex macros, local labels + +GCC allows you to declare @dfn{local labels} in any nested block +scope. A local label is just like an ordinary label, but you can +only reference it (with a @code{goto} statement, or by taking its +address) within the block in which it was declared. + +A local label declaration looks like this: + +@smallexample +__label__ @var{label}; +@end smallexample + +@noindent +or + +@smallexample +__label__ @var{label1}, @var{label2}, /* @r{@dots{}} */; +@end smallexample + +Local label declarations must come at the beginning of the block, +before any ordinary declarations or statements. + +The label declaration defines the label @emph{name}, but does not define +the label itself. You must do this in the usual way, with +@code{@var{label}:}, within the statements of the statement expression. + +The local label feature is useful for complex macros. If a macro +contains nested loops, a @code{goto} can be useful for breaking out of +them. However, an ordinary label whose scope is the whole function +cannot be used: if the macro can be expanded several times in one +function, the label will be multiply defined in that function. A +local label avoids this problem. For example: + +@smallexample +#define SEARCH(value, array, target) \ +do @{ \ + __label__ found; \ + typeof (target) _SEARCH_target = (target); \ + typeof (*(array)) *_SEARCH_array = (array); \ + int i, j; \ + int value; \ + for (i = 0; i < max; i++) \ + for (j = 0; j < max; j++) \ + if (_SEARCH_array[i][j] == _SEARCH_target) \ + @{ (value) = i; goto found; @} \ + (value) = -1; \ + found:; \ +@} while (0) +@end smallexample + +This could also be written using a statement-expression: + +@smallexample +#define SEARCH(array, target) \ +(@{ \ + __label__ found; \ + typeof (target) _SEARCH_target = (target); \ + typeof (*(array)) *_SEARCH_array = (array); \ + int i, j; \ + int value; \ + for (i = 0; i < max; i++) \ + for (j = 0; j < max; j++) \ + if (_SEARCH_array[i][j] == _SEARCH_target) \ + @{ value = i; goto found; @} \ + value = -1; \ + found: \ + value; \ +@}) +@end smallexample + +Local label declarations also make the labels they declare visible to +nested functions, if there are any. @xref{Nested Functions}, for details. + +@node Labels as Values +@section Labels as Values +@cindex labels as values +@cindex computed gotos +@cindex goto with computed label +@cindex address of a label + +You can get the address of a label defined in the current function +(or a containing function) with the unary operator @samp{&&}. The +value has type @code{void *}. This value is a constant and can be used +wherever a constant of that type is valid. For example: + +@smallexample +void *ptr; +/* @r{@dots{}} */ +ptr = &&foo; +@end smallexample + +To use these values, you need to be able to jump to one. This is done +with the computed goto statement@footnote{The analogous feature in +Fortran is called an assigned goto, but that name seems inappropriate in +C, where one can do more than simply store label addresses in label +variables.}, @code{goto *@var{exp};}. For example, + +@smallexample +goto *ptr; +@end smallexample + +@noindent +Any expression of type @code{void *} is allowed. + +One way of using these constants is in initializing a static array that +will serve as a jump table: + +@smallexample +static void *array[] = @{ &&foo, &&bar, &&hack @}; +@end smallexample + +Then you can select a label with indexing, like this: + +@smallexample +goto *array[i]; +@end smallexample + +@noindent +Note that this does not check whether the subscript is in bounds---array +indexing in C never does that. + +Such an array of label values serves a purpose much like that of the +@code{switch} statement. The @code{switch} statement is cleaner, so +use that rather than an array unless the problem does not fit a +@code{switch} statement very well. + +Another use of label values is in an interpreter for threaded code. +The labels within the interpreter function can be stored in the +threaded code for super-fast dispatching. + +You may not use this mechanism to jump to code in a different function. +If you do that, totally unpredictable things will happen. The best way to +avoid this is to store the label address only in automatic variables and +never pass it as an argument. + +An alternate way to write the above example is + +@smallexample +static const int array[] = @{ &&foo - &&foo, &&bar - &&foo, + &&hack - &&foo @}; +goto *(&&foo + array[i]); +@end smallexample + +@noindent +This is more friendly to code living in shared libraries, as it reduces +the number of dynamic relocations that are needed, and by consequence, +allows the data to be read-only. + +@node Nested Functions +@section Nested Functions +@cindex nested functions +@cindex downward funargs +@cindex thunks + +A @dfn{nested function} is a function defined inside another function. +@c APPLE LOCAL begin nested functions 4357979 +Nested functions are not supported for GNU C++ and are disable by +default on Darwin. The @option{-fnested-functions} and +@option{-fno-nested-functions} options can be used to enable and +disable nested function suppport. The nested function's name is local +to the block where it is defined. For example, here we define a +nested function named @code{square}, and call it twice: +@c APPLE LOCAL end nested functions 4357979 + +@smallexample +@group +foo (double a, double b) +@{ + double square (double z) @{ return z * z; @} + + return square (a) + square (b); +@} +@end group +@end smallexample + +The nested function can access all the variables of the containing +function that are visible at the point of its definition. This is +called @dfn{lexical scoping}. For example, here we show a nested +function which uses an inherited variable named @code{offset}: + +@smallexample +@group +bar (int *array, int offset, int size) +@{ + int access (int *array, int index) + @{ return array[index + offset]; @} + int i; + /* @r{@dots{}} */ + for (i = 0; i < size; i++) + /* @r{@dots{}} */ access (array, i) /* @r{@dots{}} */ +@} +@end group +@end smallexample + +Nested function definitions are permitted within functions in the places +where variable definitions are allowed; that is, in any block, mixed +with the other declarations and statements in the block. + +It is possible to call the nested function from outside the scope of its +name by storing its address or passing the address to another function: + +@smallexample +hack (int *array, int size) +@{ + void store (int index, int value) + @{ array[index] = value; @} + + intermediate (store, size); +@} +@end smallexample + +Here, the function @code{intermediate} receives the address of +@code{store} as an argument. If @code{intermediate} calls @code{store}, +the arguments given to @code{store} are used to store into @code{array}. +But this technique works only so long as the containing function +(@code{hack}, in this example) does not exit. + +If you try to call the nested function through its address after the +containing function has exited, all hell will break loose. If you try +to call it after a containing scope level has exited, and if it refers +to some of the variables that are no longer in scope, you may be lucky, +but it's not wise to take the risk. If, however, the nested function +does not refer to anything that has gone out of scope, you should be +safe. + +GCC implements taking the address of a nested function using a technique +called @dfn{trampolines}. A paper describing them is available as + +@noindent +@uref{http://people.debian.org/~aaronl/Usenix88-lexic.pdf}. + +A nested function can jump to a label inherited from a containing +function, provided the label was explicitly declared in the containing +function (@pxref{Local Labels}). Such a jump returns instantly to the +containing function, exiting the nested function which did the +@code{goto} and any intermediate functions as well. Here is an example: + +@smallexample +@group +bar (int *array, int offset, int size) +@{ + __label__ failure; + int access (int *array, int index) + @{ + if (index > size) + goto failure; + return array[index + offset]; + @} + int i; + /* @r{@dots{}} */ + for (i = 0; i < size; i++) + /* @r{@dots{}} */ access (array, i) /* @r{@dots{}} */ + /* @r{@dots{}} */ + return 0; + + /* @r{Control comes here from @code{access} + if it detects an error.} */ + failure: + return -1; +@} +@end group +@end smallexample + +A nested function always has no linkage. Declaring one with +@code{extern} or @code{static} is erroneous. If you need to declare the nested function +before its definition, use @code{auto} (which is otherwise meaningless +for function declarations). + +@smallexample +bar (int *array, int offset, int size) +@{ + __label__ failure; + auto int access (int *, int); + /* @r{@dots{}} */ + int access (int *array, int index) + @{ + if (index > size) + goto failure; + return array[index + offset]; + @} + /* @r{@dots{}} */ +@} +@end smallexample + +@node Constructing Calls +@section Constructing Function Calls +@cindex constructing calls +@cindex forwarding calls + +Using the built-in functions described below, you can record +the arguments a function received, and call another function +with the same arguments, without knowing the number or types +of the arguments. + +You can also record the return value of that function call, +and later return that value, without knowing what data type +the function tried to return (as long as your caller expects +that data type). + +However, these built-in functions may interact badly with some +sophisticated features or other extensions of the language. It +is, therefore, not recommended to use them outside very simple +functions acting as mere forwarders for their arguments. + +@deftypefn {Built-in Function} {void *} __builtin_apply_args () +This built-in function returns a pointer to data +describing how to perform a call with the same arguments as were passed +to the current function. + +The function saves the arg pointer register, structure value address, +and all registers that might be used to pass arguments to a function +into a block of memory allocated on the stack. Then it returns the +address of that block. +@end deftypefn + +@deftypefn {Built-in Function} {void *} __builtin_apply (void (*@var{function})(), void *@var{arguments}, size_t @var{size}) +This built-in function invokes @var{function} +with a copy of the parameters described by @var{arguments} +and @var{size}. + +The value of @var{arguments} should be the value returned by +@code{__builtin_apply_args}. The argument @var{size} specifies the size +of the stack argument data, in bytes. + +This function returns a pointer to data describing +how to return whatever value was returned by @var{function}. The data +is saved in a block of memory allocated on the stack. + +It is not always simple to compute the proper value for @var{size}. The +value is used by @code{__builtin_apply} to compute the amount of data +that should be pushed on the stack and copied from the incoming argument +area. +@end deftypefn + +@deftypefn {Built-in Function} {void} __builtin_return (void *@var{result}) +This built-in function returns the value described by @var{result} from +the containing function. You should specify, for @var{result}, a value +returned by @code{__builtin_apply}. +@end deftypefn + +@node Typeof +@section Referring to a Type with @code{typeof} +@findex typeof +@findex sizeof +@cindex macros, types of arguments + +Another way to refer to the type of an expression is with @code{typeof}. +The syntax of using of this keyword looks like @code{sizeof}, but the +construct acts semantically like a type name defined with @code{typedef}. + +There are two ways of writing the argument to @code{typeof}: with an +expression or with a type. Here is an example with an expression: + +@smallexample +typeof (x[0](1)) +@end smallexample + +@noindent +This assumes that @code{x} is an array of pointers to functions; +the type described is that of the values of the functions. + +Here is an example with a typename as the argument: + +@smallexample +typeof (int *) +@end smallexample + +@noindent +Here the type described is that of pointers to @code{int}. + +If you are writing a header file that must work when included in ISO C +programs, write @code{__typeof__} instead of @code{typeof}. +@xref{Alternate Keywords}. + +A @code{typeof}-construct can be used anywhere a typedef name could be +used. For example, you can use it in a declaration, in a cast, or inside +of @code{sizeof} or @code{typeof}. + +@code{typeof} is often useful in conjunction with the +statements-within-expressions feature. Here is how the two together can +be used to define a safe ``maximum'' macro that operates on any +arithmetic type and evaluates each of its arguments exactly once: + +@smallexample +#define max(a,b) \ + (@{ typeof (a) _a = (a); \ + typeof (b) _b = (b); \ + _a > _b ? _a : _b; @}) +@end smallexample + +@cindex underscores in variables in macros +@cindex @samp{_} in variables in macros +@cindex local variables in macros +@cindex variables, local, in macros +@cindex macros, local variables in + +The reason for using names that start with underscores for the local +variables is to avoid conflicts with variable names that occur within the +expressions that are substituted for @code{a} and @code{b}. Eventually we +hope to design a new form of declaration syntax that allows you to declare +variables whose scopes start only after their initializers; this will be a +more reliable way to prevent such conflicts. + +@noindent +Some more examples of the use of @code{typeof}: + +@itemize @bullet +@item +This declares @code{y} with the type of what @code{x} points to. + +@smallexample +typeof (*x) y; +@end smallexample + +@item +This declares @code{y} as an array of such values. + +@smallexample +typeof (*x) y[4]; +@end smallexample + +@item +This declares @code{y} as an array of pointers to characters: + +@smallexample +typeof (typeof (char *)[4]) y; +@end smallexample + +@noindent +It is equivalent to the following traditional C declaration: + +@smallexample +char *y[4]; +@end smallexample + +To see the meaning of the declaration using @code{typeof}, and why it +might be a useful way to write, rewrite it with these macros: + +@smallexample +#define pointer(T) typeof(T *) +#define array(T, N) typeof(T [N]) +@end smallexample + +@noindent +Now the declaration can be rewritten this way: + +@smallexample +array (pointer (char), 4) y; +@end smallexample + +@noindent +Thus, @code{array (pointer (char), 4)} is the type of arrays of 4 +pointers to @code{char}. +@end itemize + +@emph{Compatibility Note:} In addition to @code{typeof}, GCC 2 supported +a more limited extension which permitted one to write + +@smallexample +typedef @var{T} = @var{expr}; +@end smallexample + +@noindent +with the effect of declaring @var{T} to have the type of the expression +@var{expr}. This extension does not work with GCC 3 (versions between +3.0 and 3.2 will crash; 3.2.1 and later give an error). Code which +relies on it should be rewritten to use @code{typeof}: + +@smallexample +typedef typeof(@var{expr}) @var{T}; +@end smallexample + +@noindent +This will work with all versions of GCC@. + +@node Conditionals +@section Conditionals with Omitted Operands +@cindex conditional expressions, extensions +@cindex omitted middle-operands +@cindex middle-operands, omitted +@cindex extensions, @code{?:} +@cindex @code{?:} extensions + +The middle operand in a conditional expression may be omitted. Then +if the first operand is nonzero, its value is the value of the conditional +expression. + +Therefore, the expression + +@smallexample +x ? : y +@end smallexample + +@noindent +has the value of @code{x} if that is nonzero; otherwise, the value of +@code{y}. + +This example is perfectly equivalent to + +@smallexample +x ? x : y +@end smallexample + +@cindex side effect in ?: +@cindex ?: side effect +@noindent +In this simple case, the ability to omit the middle operand is not +especially useful. When it becomes useful is when the first operand does, +or may (if it is a macro argument), contain a side effect. Then repeating +the operand in the middle would perform the side effect twice. Omitting +the middle operand uses the value already computed without the undesirable +effects of recomputing it. + +@node Long Long +@section Double-Word Integers +@cindex @code{long long} data types +@cindex double-word arithmetic +@cindex multiprecision arithmetic +@cindex @code{LL} integer suffix +@cindex @code{ULL} integer suffix + +ISO C99 supports data types for integers that are at least 64 bits wide, +and as an extension GCC supports them in C89 mode and in C++. +Simply write @code{long long int} for a signed integer, or +@code{unsigned long long int} for an unsigned integer. To make an +integer constant of type @code{long long int}, add the suffix @samp{LL} +to the integer. To make an integer constant of type @code{unsigned long +long int}, add the suffix @samp{ULL} to the integer. + +You can use these types in arithmetic like any other integer types. +Addition, subtraction, and bitwise boolean operations on these types +are open-coded on all types of machines. Multiplication is open-coded +if the machine supports fullword-to-doubleword a widening multiply +instruction. Division and shifts are open-coded only on machines that +provide special support. The operations that are not open-coded use +special library routines that come with GCC@. + +There may be pitfalls when you use @code{long long} types for function +arguments, unless you declare function prototypes. If a function +expects type @code{int} for its argument, and you pass a value of type +@code{long long int}, confusion will result because the caller and the +subroutine will disagree about the number of bytes for the argument. +Likewise, if the function expects @code{long long int} and you pass +@code{int}. The best way to avoid such problems is to use prototypes. + +@node Complex +@section Complex Numbers +@cindex complex numbers +@cindex @code{_Complex} keyword +@cindex @code{__complex__} keyword + +ISO C99 supports complex floating data types, and as an extension GCC +supports them in C89 mode and in C++, and supports complex integer data +types which are not part of ISO C99. You can declare complex types +using the keyword @code{_Complex}. As an extension, the older GNU +keyword @code{__complex__} is also supported. + +For example, @samp{_Complex double x;} declares @code{x} as a +variable whose real part and imaginary part are both of type +@code{double}. @samp{_Complex short int y;} declares @code{y} to +have real and imaginary parts of type @code{short int}; this is not +likely to be useful, but it shows that the set of complex types is +complete. + +To write a constant with a complex data type, use the suffix @samp{i} or +@samp{j} (either one; they are equivalent). For example, @code{2.5fi} +has type @code{_Complex float} and @code{3i} has type +@code{_Complex int}. Such a constant always has a pure imaginary +value, but you can form any complex value you like by adding one to a +real constant. This is a GNU extension; if you have an ISO C99 +conforming C library (such as GNU libc), and want to construct complex +constants of floating type, you should include @code{<complex.h>} and +use the macros @code{I} or @code{_Complex_I} instead. + +@cindex @code{__real__} keyword +@cindex @code{__imag__} keyword +To extract the real part of a complex-valued expression @var{exp}, write +@code{__real__ @var{exp}}. Likewise, use @code{__imag__} to +extract the imaginary part. This is a GNU extension; for values of +floating type, you should use the ISO C99 functions @code{crealf}, +@code{creal}, @code{creall}, @code{cimagf}, @code{cimag} and +@code{cimagl}, declared in @code{<complex.h>} and also provided as +built-in functions by GCC@. + +@cindex complex conjugation +The operator @samp{~} performs complex conjugation when used on a value +with a complex type. This is a GNU extension; for values of +floating type, you should use the ISO C99 functions @code{conjf}, +@code{conj} and @code{conjl}, declared in @code{<complex.h>} and also +provided as built-in functions by GCC@. + +GCC can allocate complex automatic variables in a noncontiguous +fashion; it's even possible for the real part to be in a register while +the imaginary part is on the stack (or vice-versa). Only the DWARF2 +debug info format can represent this, so use of DWARF2 is recommended. +If you are using the stabs debug info format, GCC describes a noncontiguous +complex variable as if it were two separate variables of noncomplex type. +If the variable's actual name is @code{foo}, the two fictitious +variables are named @code{foo$real} and @code{foo$imag}. You can +examine and set these two fictitious variables with your debugger. + +@node Decimal Float +@section Decimal Floating Types +@cindex decimal floating types +@cindex @code{_Decimal32} data type +@cindex @code{_Decimal64} data type +@cindex @code{_Decimal128} data type +@cindex @code{df} integer suffix +@cindex @code{dd} integer suffix +@cindex @code{dl} integer suffix +@cindex @code{DF} integer suffix +@cindex @code{DD} integer suffix +@cindex @code{DL} integer suffix + +As an extension, the GNU C compiler supports decimal floating types as +defined in the N1176 draft of ISO/IEC WDTR24732. Support for decimal +floating types in GCC will evolve as the draft technical report changes. +Calling conventions for any target might also change. Not all targets +support decimal floating types. + +The decimal floating types are @code{_Decimal32}, @code{_Decimal64}, and +@code{_Decimal128}. They use a radix of ten, unlike the floating types +@code{float}, @code{double}, and @code{long double} whose radix is not +specified by the C standard but is usually two. + +Support for decimal floating types includes the arithmetic operators +add, subtract, multiply, divide; unary arithmetic operators; +relational operators; equality operators; and conversions to and from +integer and other floating types. Use a suffix @samp{df} or +@samp{DF} in a literal constant of type @code{_Decimal32}, @samp{dd} +or @samp{DD} for @code{_Decimal64}, and @samp{dl} or @samp{DL} for +@code{_Decimal128}. + +GCC support of decimal float as specified by the draft technical report +is incomplete: + +@itemize @bullet +@item +Translation time data type (TTDT) is not supported. + +@item +Characteristics of decimal floating types are defined in header file +@file{decfloat.h} rather than @file{float.h}. + +@item +When the value of a decimal floating type cannot be represented in the +integer type to which it is being converted, the result is undefined +rather than the result value specified by the draft technical report. +@end itemize + +Types @code{_Decimal32}, @code{_Decimal64}, and @code{_Decimal128} +are supported by the DWARF2 debug information format. + +@node Hex Floats +@section Hex Floats +@cindex hex floats + +ISO C99 supports floating-point numbers written not only in the usual +decimal notation, such as @code{1.55e1}, but also numbers such as +@code{0x1.fp3} written in hexadecimal format. As a GNU extension, GCC +supports this in C89 mode (except in some cases when strictly +conforming) and in C++. In that format the +@samp{0x} hex introducer and the @samp{p} or @samp{P} exponent field are +mandatory. The exponent is a decimal number that indicates the power of +2 by which the significant part will be multiplied. Thus @samp{0x1.f} is +@tex +$1 {15\over16}$, +@end tex +@ifnottex +1 15/16, +@end ifnottex +@samp{p3} multiplies it by 8, and the value of @code{0x1.fp3} +is the same as @code{1.55e1}. + +Unlike for floating-point numbers in the decimal notation the exponent +is always required in the hexadecimal notation. Otherwise the compiler +would not be able to resolve the ambiguity of, e.g., @code{0x1.f}. This +could mean @code{1.0f} or @code{1.9375} since @samp{f} is also the +extension for floating-point constants of type @code{float}. + +@node Zero Length +@section Arrays of Length Zero +@cindex arrays of length zero +@cindex zero-length arrays +@cindex length-zero arrays +@cindex flexible array members + +Zero-length arrays are allowed in GNU C@. They are very useful as the +last element of a structure which is really a header for a variable-length +object: + +@smallexample +struct line @{ + int length; + char contents[0]; +@}; + +struct line *thisline = (struct line *) + malloc (sizeof (struct line) + this_length); +thisline->length = this_length; +@end smallexample + +In ISO C90, you would have to give @code{contents} a length of 1, which +means either you waste space or complicate the argument to @code{malloc}. + +In ISO C99, you would use a @dfn{flexible array member}, which is +slightly different in syntax and semantics: + +@itemize @bullet +@item +Flexible array members are written as @code{contents[]} without +the @code{0}. + +@item +Flexible array members have incomplete type, and so the @code{sizeof} +operator may not be applied. As a quirk of the original implementation +of zero-length arrays, @code{sizeof} evaluates to zero. + +@item +Flexible array members may only appear as the last member of a +@code{struct} that is otherwise non-empty. + +@item +A structure containing a flexible array member, or a union containing +such a structure (possibly recursively), may not be a member of a +structure or an element of an array. (However, these uses are +permitted by GCC as extensions.) +@end itemize + +GCC versions before 3.0 allowed zero-length arrays to be statically +initialized, as if they were flexible arrays. In addition to those +cases that were useful, it also allowed initializations in situations +that would corrupt later data. Non-empty initialization of zero-length +arrays is now treated like any case where there are more initializer +elements than the array holds, in that a suitable warning about "excess +elements in array" is given, and the excess elements (all of them, in +this case) are ignored. + +Instead GCC allows static initialization of flexible array members. +This is equivalent to defining a new structure containing the original +structure followed by an array of sufficient size to contain the data. +I.e.@: in the following, @code{f1} is constructed as if it were declared +like @code{f2}. + +@smallexample +struct f1 @{ + int x; int y[]; +@} f1 = @{ 1, @{ 2, 3, 4 @} @}; + +struct f2 @{ + struct f1 f1; int data[3]; +@} f2 = @{ @{ 1 @}, @{ 2, 3, 4 @} @}; +@end smallexample + +@noindent +The convenience of this extension is that @code{f1} has the desired +type, eliminating the need to consistently refer to @code{f2.f1}. + +This has symmetry with normal static arrays, in that an array of +unknown size is also written with @code{[]}. + +Of course, this extension only makes sense if the extra data comes at +the end of a top-level object, as otherwise we would be overwriting +data at subsequent offsets. To avoid undue complication and confusion +with initialization of deeply nested arrays, we simply disallow any +non-empty initialization except when the structure is the top-level +object. For example: + +@smallexample +struct foo @{ int x; int y[]; @}; +struct bar @{ struct foo z; @}; + +struct foo a = @{ 1, @{ 2, 3, 4 @} @}; // @r{Valid.} +struct bar b = @{ @{ 1, @{ 2, 3, 4 @} @} @}; // @r{Invalid.} +struct bar c = @{ @{ 1, @{ @} @} @}; // @r{Valid.} +struct foo d[1] = @{ @{ 1 @{ 2, 3, 4 @} @} @}; // @r{Invalid.} +@end smallexample + +@node Empty Structures +@section Structures With No Members +@cindex empty structures +@cindex zero-size structures + +GCC permits a C structure to have no members: + +@smallexample +struct empty @{ +@}; +@end smallexample + +The structure will have size zero. In C++, empty structures are part +of the language. G++ treats empty structures as if they had a single +member of type @code{char}. + +@node Variable Length +@section Arrays of Variable Length +@cindex variable-length arrays +@cindex arrays of variable length +@cindex VLAs + +Variable-length automatic arrays are allowed in ISO C99, and as an +extension GCC accepts them in C89 mode and in C++. (However, GCC's +implementation of variable-length arrays does not yet conform in detail +to the ISO C99 standard.) These arrays are +declared like any other automatic arrays, but with a length that is not +a constant expression. The storage is allocated at the point of +declaration and deallocated when the brace-level is exited. For +example: + +@smallexample +FILE * +concat_fopen (char *s1, char *s2, char *mode) +@{ + char str[strlen (s1) + strlen (s2) + 1]; + strcpy (str, s1); + strcat (str, s2); + return fopen (str, mode); +@} +@end smallexample + +@cindex scope of a variable length array +@cindex variable-length array scope +@cindex deallocating variable length arrays +Jumping or breaking out of the scope of the array name deallocates the +storage. Jumping into the scope is not allowed; you get an error +message for it. + +@cindex @code{alloca} vs variable-length arrays +You can use the function @code{alloca} to get an effect much like +variable-length arrays. The function @code{alloca} is available in +many other C implementations (but not in all). On the other hand, +variable-length arrays are more elegant. + +There are other differences between these two methods. Space allocated +with @code{alloca} exists until the containing @emph{function} returns. +The space for a variable-length array is deallocated as soon as the array +name's scope ends. (If you use both variable-length arrays and +@code{alloca} in the same function, deallocation of a variable-length array +will also deallocate anything more recently allocated with @code{alloca}.) + +You can also use variable-length arrays as arguments to functions: + +@smallexample +struct entry +tester (int len, char data[len][len]) +@{ + /* @r{@dots{}} */ +@} +@end smallexample + +The length of an array is computed once when the storage is allocated +and is remembered for the scope of the array in case you access it with +@code{sizeof}. + +If you want to pass the array first and the length afterward, you can +use a forward declaration in the parameter list---another GNU extension. + +@smallexample +struct entry +tester (int len; char data[len][len], int len) +@{ + /* @r{@dots{}} */ +@} +@end smallexample + +@cindex parameter forward declaration +The @samp{int len} before the semicolon is a @dfn{parameter forward +declaration}, and it serves the purpose of making the name @code{len} +known when the declaration of @code{data} is parsed. + +You can write any number of such parameter forward declarations in the +parameter list. They can be separated by commas or semicolons, but the +last one must end with a semicolon, which is followed by the ``real'' +parameter declarations. Each forward declaration must match a ``real'' +declaration in parameter name and data type. ISO C99 does not support +parameter forward declarations. + +@node Variadic Macros +@section Macros with a Variable Number of Arguments. +@cindex variable number of arguments +@cindex macro with variable arguments +@cindex rest argument (in macro) +@cindex variadic macros + +In the ISO C standard of 1999, a macro can be declared to accept a +variable number of arguments much as a function can. The syntax for +defining the macro is similar to that of a function. Here is an +example: + +@smallexample +#define debug(format, ...) fprintf (stderr, format, __VA_ARGS__) +@end smallexample + +Here @samp{@dots{}} is a @dfn{variable argument}. In the invocation of +such a macro, it represents the zero or more tokens until the closing +parenthesis that ends the invocation, including any commas. This set of +tokens replaces the identifier @code{__VA_ARGS__} in the macro body +wherever it appears. See the CPP manual for more information. + +GCC has long supported variadic macros, and used a different syntax that +allowed you to give a name to the variable arguments just like any other +argument. Here is an example: + +@smallexample +#define debug(format, args...) fprintf (stderr, format, args) +@end smallexample + +This is in all ways equivalent to the ISO C example above, but arguably +more readable and descriptive. + +GNU CPP has two further variadic macro extensions, and permits them to +be used with either of the above forms of macro definition. + +In standard C, you are not allowed to leave the variable argument out +entirely; but you are allowed to pass an empty argument. For example, +this invocation is invalid in ISO C, because there is no comma after +the string: + +@smallexample +debug ("A message") +@end smallexample + +GNU CPP permits you to completely omit the variable arguments in this +way. In the above examples, the compiler would complain, though since +the expansion of the macro still has the extra comma after the format +string. + +To help solve this problem, CPP behaves specially for variable arguments +used with the token paste operator, @samp{##}. If instead you write + +@smallexample +#define debug(format, ...) fprintf (stderr, format, ## __VA_ARGS__) +@end smallexample + +and if the variable arguments are omitted or empty, the @samp{##} +operator causes the preprocessor to remove the comma before it. If you +do provide some variable arguments in your macro invocation, GNU CPP +does not complain about the paste operation and instead places the +variable arguments after the comma. Just like any other pasted macro +argument, these arguments are not macro expanded. + +@node Escaped Newlines +@section Slightly Looser Rules for Escaped Newlines +@cindex escaped newlines +@cindex newlines (escaped) + +Recently, the preprocessor has relaxed its treatment of escaped +newlines. Previously, the newline had to immediately follow a +backslash. The current implementation allows whitespace in the form +of spaces, horizontal and vertical tabs, and form feeds between the +backslash and the subsequent newline. The preprocessor issues a +warning, but treats it as a valid escaped newline and combines the two +lines to form a single logical line. This works within comments and +tokens, as well as between tokens. Comments are @emph{not} treated as +whitespace for the purposes of this relaxation, since they have not +yet been replaced with spaces. + +@node Subscripting +@section Non-Lvalue Arrays May Have Subscripts +@cindex subscripting +@cindex arrays, non-lvalue + +@cindex subscripting and function values +In ISO C99, arrays that are not lvalues still decay to pointers, and +may be subscripted, although they may not be modified or used after +the next sequence point and the unary @samp{&} operator may not be +applied to them. As an extension, GCC allows such arrays to be +subscripted in C89 mode, though otherwise they do not decay to +pointers outside C99 mode. For example, +this is valid in GNU C though not valid in C89: + +@smallexample +@group +struct foo @{int a[4];@}; + +struct foo f(); + +bar (int index) +@{ + return f().a[index]; +@} +@end group +@end smallexample + +@node Pointer Arith +@section Arithmetic on @code{void}- and Function-Pointers +@cindex void pointers, arithmetic +@cindex void, size of pointer to +@cindex function pointers, arithmetic +@cindex function, size of pointer to + +In GNU C, addition and subtraction operations are supported on pointers to +@code{void} and on pointers to functions. This is done by treating the +size of a @code{void} or of a function as 1. + +A consequence of this is that @code{sizeof} is also allowed on @code{void} +and on function types, and returns 1. + +@opindex Wpointer-arith +The option @option{-Wpointer-arith} requests a warning if these extensions +are used. + +@node Initializers +@section Non-Constant Initializers +@cindex initializers, non-constant +@cindex non-constant initializers + +As in standard C++ and ISO C99, the elements of an aggregate initializer for an +automatic variable are not required to be constant expressions in GNU C@. +Here is an example of an initializer with run-time varying elements: + +@smallexample +foo (float f, float g) +@{ + float beat_freqs[2] = @{ f-g, f+g @}; + /* @r{@dots{}} */ +@} +@end smallexample + +@node Compound Literals +@section Compound Literals +@cindex constructor expressions +@cindex initializations in expressions +@cindex structures, constructor expression +@cindex expressions, constructor +@cindex compound literals +@c The GNU C name for what C99 calls compound literals was "constructor expressions". + +ISO C99 supports compound literals. A compound literal looks like +a cast containing an initializer. Its value is an object of the +type specified in the cast, containing the elements specified in +the initializer; it is an lvalue. As an extension, GCC supports +compound literals in C89 mode and in C++. + +Usually, the specified type is a structure. Assume that +@code{struct foo} and @code{structure} are declared as shown: + +@smallexample +struct foo @{int a; char b[2];@} structure; +@end smallexample + +@noindent +Here is an example of constructing a @code{struct foo} with a compound literal: + +@smallexample +structure = ((struct foo) @{x + y, 'a', 0@}); +@end smallexample + +@noindent +This is equivalent to writing the following: + +@smallexample +@{ + struct foo temp = @{x + y, 'a', 0@}; + structure = temp; +@} +@end smallexample + +You can also construct an array. If all the elements of the compound literal +are (made up of) simple constant expressions, suitable for use in +initializers of objects of static storage duration, then the compound +literal can be coerced to a pointer to its first element and used in +such an initializer, as shown here: + +@smallexample +char **foo = (char *[]) @{ "x", "y", "z" @}; +@end smallexample + +Compound literals for scalar types and union types are is +also allowed, but then the compound literal is equivalent +to a cast. + +As a GNU extension, GCC allows initialization of objects with static storage +duration by compound literals (which is not possible in ISO C99, because +the initializer is not a constant). +It is handled as if the object was initialized only with the bracket +enclosed list if the types of the compound literal and the object match. +The initializer list of the compound literal must be constant. +If the object being initialized has array type of unknown size, the size is +determined by compound literal size. + +@smallexample +static struct foo x = (struct foo) @{1, 'a', 'b'@}; +static int y[] = (int []) @{1, 2, 3@}; +static int z[] = (int [3]) @{1@}; +@end smallexample + +@noindent +The above lines are equivalent to the following: +@smallexample +static struct foo x = @{1, 'a', 'b'@}; +static int y[] = @{1, 2, 3@}; +static int z[] = @{1, 0, 0@}; +@end smallexample + +@node Designated Inits +@section Designated Initializers +@cindex initializers with labeled elements +@cindex labeled elements in initializers +@cindex case labels in initializers +@cindex designated initializers + +Standard C89 requires the elements of an initializer to appear in a fixed +order, the same as the order of the elements in the array or structure +being initialized. + +In ISO C99 you can give the elements in any order, specifying the array +indices or structure field names they apply to, and GNU C allows this as +an extension in C89 mode as well. This extension is not +implemented in GNU C++. + +To specify an array index, write +@samp{[@var{index}] =} before the element value. For example, + +@smallexample +int a[6] = @{ [4] = 29, [2] = 15 @}; +@end smallexample + +@noindent +is equivalent to + +@smallexample +int a[6] = @{ 0, 0, 15, 0, 29, 0 @}; +@end smallexample + +@noindent +The index values must be constant expressions, even if the array being +initialized is automatic. + +An alternative syntax for this which has been obsolete since GCC 2.5 but +GCC still accepts is to write @samp{[@var{index}]} before the element +value, with no @samp{=}. + +To initialize a range of elements to the same value, write +@samp{[@var{first} ... @var{last}] = @var{value}}. This is a GNU +extension. For example, + +@smallexample +int widths[] = @{ [0 ... 9] = 1, [10 ... 99] = 2, [100] = 3 @}; +@end smallexample + +@noindent +If the value in it has side-effects, the side-effects will happen only once, +not for each initialized field by the range initializer. + +@noindent +Note that the length of the array is the highest value specified +plus one. + +In a structure initializer, specify the name of a field to initialize +with @samp{.@var{fieldname} =} before the element value. For example, +given the following structure, + +@smallexample +struct point @{ int x, y; @}; +@end smallexample + +@noindent +the following initialization + +@smallexample +struct point p = @{ .y = yvalue, .x = xvalue @}; +@end smallexample + +@noindent +is equivalent to + +@smallexample +struct point p = @{ xvalue, yvalue @}; +@end smallexample + +Another syntax which has the same meaning, obsolete since GCC 2.5, is +@samp{@var{fieldname}:}, as shown here: + +@smallexample +struct point p = @{ y: yvalue, x: xvalue @}; +@end smallexample + +@cindex designators +The @samp{[@var{index}]} or @samp{.@var{fieldname}} is known as a +@dfn{designator}. You can also use a designator (or the obsolete colon +syntax) when initializing a union, to specify which element of the union +should be used. For example, + +@smallexample +union foo @{ int i; double d; @}; + +union foo f = @{ .d = 4 @}; +@end smallexample + +@noindent +will convert 4 to a @code{double} to store it in the union using +the second element. By contrast, casting 4 to type @code{union foo} +would store it into the union as the integer @code{i}, since it is +an integer. (@xref{Cast to Union}.) + +You can combine this technique of naming elements with ordinary C +initialization of successive elements. Each initializer element that +does not have a designator applies to the next consecutive element of the +array or structure. For example, + +@smallexample +int a[6] = @{ [1] = v1, v2, [4] = v4 @}; +@end smallexample + +@noindent +is equivalent to + +@smallexample +int a[6] = @{ 0, v1, v2, 0, v4, 0 @}; +@end smallexample + +Labeling the elements of an array initializer is especially useful +when the indices are characters or belong to an @code{enum} type. +For example: + +@smallexample +int whitespace[256] + = @{ [' '] = 1, ['\t'] = 1, ['\h'] = 1, + ['\f'] = 1, ['\n'] = 1, ['\r'] = 1 @}; +@end smallexample + +@cindex designator lists +You can also write a series of @samp{.@var{fieldname}} and +@samp{[@var{index}]} designators before an @samp{=} to specify a +nested subobject to initialize; the list is taken relative to the +subobject corresponding to the closest surrounding brace pair. For +example, with the @samp{struct point} declaration above: + +@smallexample +struct point ptarray[10] = @{ [2].y = yv2, [2].x = xv2, [0].x = xv0 @}; +@end smallexample + +@noindent +If the same field is initialized multiple times, it will have value from +the last initialization. If any such overridden initialization has +side-effect, it is unspecified whether the side-effect happens or not. +Currently, GCC will discard them and issue a warning. + +@node Case Ranges +@section Case Ranges +@cindex case ranges +@cindex ranges in case statements + +You can specify a range of consecutive values in a single @code{case} label, +like this: + +@smallexample +case @var{low} ... @var{high}: +@end smallexample + +@noindent +This has the same effect as the proper number of individual @code{case} +labels, one for each integer value from @var{low} to @var{high}, inclusive. + +This feature is especially useful for ranges of ASCII character codes: + +@smallexample +case 'A' ... 'Z': +@end smallexample + +@strong{Be careful:} Write spaces around the @code{...}, for otherwise +it may be parsed wrong when you use it with integer values. For example, +write this: + +@smallexample +case 1 ... 5: +@end smallexample + +@noindent +rather than this: + +@smallexample +case 1...5: +@end smallexample + +@node Cast to Union +@section Cast to a Union Type +@cindex cast to a union +@cindex union, casting to a + +A cast to union type is similar to other casts, except that the type +specified is a union type. You can specify the type either with +@code{union @var{tag}} or with a typedef name. A cast to union is actually +a constructor though, not a cast, and hence does not yield an lvalue like +normal casts. (@xref{Compound Literals}.) + +The types that may be cast to the union type are those of the members +of the union. Thus, given the following union and variables: + +@smallexample +union foo @{ int i; double d; @}; +int x; +double y; +@end smallexample + +@noindent +both @code{x} and @code{y} can be cast to type @code{union foo}. + +Using the cast as the right-hand side of an assignment to a variable of +union type is equivalent to storing in a member of the union: + +@smallexample +union foo u; +/* @r{@dots{}} */ +u = (union foo) x @equiv{} u.i = x +u = (union foo) y @equiv{} u.d = y +@end smallexample + +You can also use the union cast as a function argument: + +@smallexample +void hack (union foo); +/* @r{@dots{}} */ +hack ((union foo) x); +@end smallexample + +@node Mixed Declarations +@section Mixed Declarations and Code +@cindex mixed declarations and code +@cindex declarations, mixed with code +@cindex code, mixed with declarations + +ISO C99 and ISO C++ allow declarations and code to be freely mixed +within compound statements. As an extension, GCC also allows this in +C89 mode. For example, you could do: + +@smallexample +int i; +/* @r{@dots{}} */ +i++; +int j = i + 2; +@end smallexample + +Each identifier is visible from where it is declared until the end of +the enclosing block. + +@node Function Attributes +@section Declaring Attributes of Functions +@cindex function attributes +@cindex declaring attributes of functions +@cindex functions that never return +@cindex functions that return more than once +@cindex functions that have no side effects +@cindex functions in arbitrary sections +@cindex functions that behave like malloc +@cindex @code{volatile} applied to function +@cindex @code{const} applied to function +@cindex functions with @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style arguments +@cindex functions with non-null pointer arguments +@cindex functions that are passed arguments in registers on the 386 +@cindex functions that pop the argument stack on the 386 +@cindex functions that do not pop the argument stack on the 386 + +In GNU C, you declare certain things about functions called in your program +which help the compiler optimize function calls and check your code more +carefully. + +The keyword @code{__attribute__} allows you to specify special +attributes when making a declaration. This keyword is followed by an +attribute specification inside double parentheses. The following +attributes are currently defined for functions on all targets: +@c APPLE LOCAL mainline aligned functions 5933878 +@code{aligned}, +@code{noreturn}, @code{returns_twice}, @code{noinline}, @code{always_inline}, +@c APPLE LOCAL nodebug +@code{nodebug}, +@c APPLE LOCAL regparmandstackparm +@code{regparmandstackparm}, +@code{flatten}, @code{pure}, @code{const}, @code{nothrow}, @code{sentinel}, +@code{format}, @code{format_arg}, @code{no_instrument_function}, +@code{section}, @code{constructor}, @code{destructor}, @code{used}, +@code{unused}, @code{deprecated}, @code{weak}, @code{malloc}, +@code{alias}, @code{warn_unused_result}, @code{nonnull}, +@code{gnu_inline} and @code{externally_visible}. Several other +attributes are defined for functions on particular target systems. Other +attributes, including @code{section} are supported for variables declarations +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +(@pxref{Variable Attributes}), for types (@pxref{Type Attributes}), +and labels (@pxref{Label Attributes}). + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +You may also specify attributes with @samp{__} preceding and following +each keyword. This allows you to use them in header files without +being concerned about a possible macro of the same name. For example, +you may use @code{__noreturn__} instead of @code{noreturn}. + +@xref{Attribute Syntax}, for details of the exact syntax for using +attributes. + +@table @code +@c Keep this table alphabetized by attribute name. Treat _ as space. + +@item alias ("@var{target}") +@cindex @code{alias} attribute +The @code{alias} attribute causes the declaration to be emitted as an +alias for another symbol, which must be specified. For instance, + +@smallexample +void __f () @{ /* @r{Do something.} */; @} +void f () __attribute__ ((weak, alias ("__f"))); +@end smallexample + +defines @samp{f} to be a weak alias for @samp{__f}. In C++, the +mangled name for the target must be used. It is an error if @samp{__f} +is not defined in the same translation unit. + +Not all target machines support this attribute. + +@c APPLE LOCAL begin mainline aligned functions 5933878 +@item aligned (@var{alignment}) +@cindex @code{aligned} attribute +This attribute specifies a minimum alignment for the function, +measured in bytes. + +You cannot use this attribute to decrease the alignment of a function, +only to increase it. However, when you explicitly specify a function +alignment this will override the effect of the +@option{-falign-functions} (@pxref{Optimize Options}) option for this +function. + +Note that the effectiveness of @code{aligned} attributes may be +limited by inherent limitations in your linker. On many systems, the +linker is only able to arrange for functions to be aligned up to a +certain maximum alignment. (For some linkers, the maximum supported +alignment may be very very small.) See your linker documentation for +further information. + +The @code{aligned} attribute can also be used for variables and fields +(@pxref{Variable Attributes}.) +@c APPLE LOCAL end mainline aligned functions 5933878 + +@item always_inline +@cindex @code{always_inline} function attribute +Generally, functions are not inlined unless optimization is specified. +For functions declared inline, this attribute inlines the function even +if no optimization level was specified. + +@item gnu_inline +@cindex @code{gnu_inline} function attribute +This attribute should be used with a function which is also declared +with the @code{inline} keyword. It directs GCC to treat the function +as if it were defined in gnu89 mode even when compiling in C99 or +gnu99 mode. + +If the function is declared @code{extern}, then this definition of the +function is used only for inlining. In no case is the function +compiled as a standalone function, not even if you take its address +explicitly. Such an address becomes an external reference, as if you +had only declared the function, and had not defined it. This has +almost the effect of a macro. The way to use this is to put a +function definition in a header file with this attribute, and put +another copy of the function, without @code{extern}, in a library +file. The definition in the header file will cause most calls to the +function to be inlined. If any uses of the function remain, they will +refer to the single copy in the library. Note that the two +definitions of the functions need not be precisely the same, although +if they do not have the same effect your program may behave oddly. + +If the function is neither @code{extern} nor @code{static}, then the +function is compiled as a standalone function, as well as being +inlined where possible. + +This is how GCC traditionally handled functions declared +@code{inline}. Since ISO C99 specifies a different semantics for +@code{inline}, this function attribute is provided as a transition +measure and as a useful feature in its own right. This attribute is +available in GCC 4.1.3 and later. It is available if either of the +preprocessor macros @code{__GNUC_GNU_INLINE__} or +@code{__GNUC_STDC_INLINE__} are defined. @xref{Inline,,An Inline +Function is As Fast As a Macro}. + +Note that since the first version of GCC to support C99 inline semantics +/* APPLE LOCAL extern inline */ +is 4.3 (4.2 for Apple's gcc), earlier versions of GCC which accept this attribute effectively +assume that it is always present, whether or not it is given explicitly. +/* APPLE LOCAL extern inline */ +In versions prior to 4.3 (4.2 for Apple's gcc), the only effect of explicitly including it is +to disable warnings about using inline functions in C99 mode. + +@c APPLE LOCAL begin nodebug +@item nodebug +@cindex @code{nodebug} function attribute +This attribute prevents debug information to be generated for the function. +This is to avoid stepping into the function which is of no interest to the +user how it is implemented. An example is the x86 vector intrinsics. +This is temporary and will be removed in some future version of the compiler. +@c APPLE LOCAL end nodebug + +@cindex @code{flatten} function attribute +@item flatten +Generally, inlining into a function is limited. For a function marked with +this attribute, every call inside this function will be inlined, if possible. +Whether the function itself is considered for inlining depends on its size and +the current inlining parameters. The @code{flatten} attribute only works +reliably in unit-at-a-time mode. + +@item cdecl +@cindex functions that do pop the argument stack on the 386 +@opindex mrtd +On the Intel 386, the @code{cdecl} attribute causes the compiler to +assume that the calling function will pop off the stack space used to +pass arguments. This is +useful to override the effects of the @option{-mrtd} switch. + +@item const +@cindex @code{const} function attribute +Many functions do not examine any values except their arguments, and +have no effects except the return value. Basically this is just slightly +more strict class than the @code{pure} attribute below, since function is not +allowed to read global memory. + +@cindex pointer arguments +Note that a function that has pointer arguments and examines the data +pointed to must @emph{not} be declared @code{const}. Likewise, a +function that calls a non-@code{const} function usually must not be +@code{const}. It does not make sense for a @code{const} function to +return @code{void}. + +The attribute @code{const} is not implemented in GCC versions earlier +than 2.5. An alternative way to declare that a function has no side +effects, which works in the current version and in some older versions, +is as follows: + +@smallexample +typedef int intfn (); + +extern const intfn square; +@end smallexample + +This approach does not work in GNU C++ from 2.6.0 on, since the language +specifies that the @samp{const} must be attached to the return value. + +@item constructor +@itemx destructor +@cindex @code{constructor} function attribute +@cindex @code{destructor} function attribute +The @code{constructor} attribute causes the function to be called +automatically before execution enters @code{main ()}. Similarly, the +@code{destructor} attribute causes the function to be called +automatically after @code{main ()} has completed or @code{exit ()} has +been called. Functions with these attributes are useful for +initializing data that will be used implicitly during the execution of +the program. + +These attributes are not currently implemented for Objective-C@. + +@item deprecated +@cindex @code{deprecated} attribute. +The @code{deprecated} attribute results in a warning if the function +is used anywhere in the source file. This is useful when identifying +functions that are expected to be removed in a future version of a +program. The warning also includes the location of the declaration +of the deprecated function, to enable users to easily find further +information about why the function is deprecated, or what they should +do instead. Note that the warnings only occurs for uses: + +@smallexample +int old_fn () __attribute__ ((deprecated)); +int old_fn (); +int (*fn_ptr)() = old_fn; +@end smallexample + +results in a warning on line 3 but not line 2. + +The @code{deprecated} attribute can also be used for variables and +types (@pxref{Variable Attributes}, @pxref{Type Attributes}.) + +@item dllexport +@cindex @code{__declspec(dllexport)} +On Microsoft Windows targets and Symbian OS targets the +@code{dllexport} attribute causes the compiler to provide a global +pointer to a pointer in a DLL, so that it can be referenced with the +@code{dllimport} attribute. On Microsoft Windows targets, the pointer +name is formed by combining @code{_imp__} and the function or variable +name. + +You can use @code{__declspec(dllexport)} as a synonym for +@code{__attribute__ ((dllexport))} for compatibility with other +compilers. + +On systems that support the @code{visibility} attribute, this +attribute also implies ``default'' visibility, unless a +@code{visibility} attribute is explicitly specified. You should avoid +the use of @code{dllexport} with ``hidden'' or ``internal'' +visibility; in the future GCC may issue an error for those cases. + +Currently, the @code{dllexport} attribute is ignored for inlined +functions, unless the @option{-fkeep-inline-functions} flag has been +used. The attribute is also ignored for undefined symbols. + +When applied to C++ classes, the attribute marks defined non-inlined +member functions and static data members as exports. Static consts +initialized in-class are not marked unless they are also defined +out-of-class. + +For Microsoft Windows targets there are alternative methods for +including the symbol in the DLL's export table such as using a +@file{.def} file with an @code{EXPORTS} section or, with GNU ld, using +the @option{--export-all} linker flag. + +@item dllimport +@cindex @code{__declspec(dllimport)} +On Microsoft Windows and Symbian OS targets, the @code{dllimport} +attribute causes the compiler to reference a function or variable via +a global pointer to a pointer that is set up by the DLL exporting the +symbol. The attribute implies @code{extern} storage. On Microsoft +Windows targets, the pointer name is formed by combining @code{_imp__} +and the function or variable name. + +You can use @code{__declspec(dllimport)} as a synonym for +@code{__attribute__ ((dllimport))} for compatibility with other +compilers. + +Currently, the attribute is ignored for inlined functions. If the +attribute is applied to a symbol @emph{definition}, an error is reported. +If a symbol previously declared @code{dllimport} is later defined, the +attribute is ignored in subsequent references, and a warning is emitted. +The attribute is also overridden by a subsequent declaration as +@code{dllexport}. + +When applied to C++ classes, the attribute marks non-inlined +member functions and static data members as imports. However, the +attribute is ignored for virtual methods to allow creation of vtables +using thunks. + +On the SH Symbian OS target the @code{dllimport} attribute also has +another affect---it can cause the vtable and run-time type information +for a class to be exported. This happens when the class has a +dllimport'ed constructor or a non-inline, non-pure virtual function +and, for either of those two conditions, the class also has a inline +constructor or destructor and has a key function that is defined in +the current translation unit. + +For Microsoft Windows based targets the use of the @code{dllimport} +attribute on functions is not necessary, but provides a small +performance benefit by eliminating a thunk in the DLL@. The use of the +@code{dllimport} attribute on imported variables was required on older +versions of the GNU linker, but can now be avoided by passing the +@option{--enable-auto-import} switch to the GNU linker. As with +functions, using the attribute for a variable eliminates a thunk in +the DLL@. + +One drawback to using this attribute is that a pointer to a function +or variable marked as @code{dllimport} cannot be used as a constant +address. On Microsoft Windows targets, the attribute can be disabled +for functions by setting the @option{-mnop-fun-dllimport} flag. + +@item eightbit_data +@cindex eight bit data on the H8/300, H8/300H, and H8S +Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified +variable should be placed into the eight bit data section. +The compiler will generate more efficient code for certain operations +on data in the eight bit data area. Note the eight bit data area is limited to +256 bytes of data. + +You must use GAS and GLD from GNU binutils version 2.7 or later for +this attribute to work correctly. + +@item exception_handler +@cindex exception handler functions on the Blackfin processor +Use this attribute on the Blackfin to indicate that the specified function +is an exception handler. The compiler will generate function entry and +exit sequences suitable for use in an exception handler when this +attribute is present. + +@item far +@cindex functions which handle memory bank switching +On 68HC11 and 68HC12 the @code{far} attribute causes the compiler to +use a calling convention that takes care of switching memory banks when +entering and leaving a function. This calling convention is also the +default when using the @option{-mlong-calls} option. + +On 68HC12 the compiler will use the @code{call} and @code{rtc} instructions +to call and return from a function. + +On 68HC11 the compiler will generate a sequence of instructions +to invoke a board-specific routine to switch the memory bank and call the +real function. The board-specific routine simulates a @code{call}. +At the end of a function, it will jump to a board-specific routine +instead of using @code{rts}. The board-specific return routine simulates +the @code{rtc}. + +@item fastcall +@cindex functions that pop the argument stack on the 386 +On the Intel 386, the @code{fastcall} attribute causes the compiler to +pass the first argument (if of integral type) in the register ECX and +the second argument (if of integral type) in the register EDX@. Subsequent +and other typed arguments are passed on the stack. The called function will +pop the arguments off the stack. If the number of arguments is variable all +arguments are pushed on the stack. + +@item format (@var{archetype}, @var{string-index}, @var{first-to-check}) +@cindex @code{format} function attribute +@opindex Wformat +The @code{format} attribute specifies that a function takes @code{printf}, +@code{scanf}, @code{strftime} or @code{strfmon} style arguments which +should be type-checked against a format string. For example, the +declaration: + +@smallexample +extern int +my_printf (void *my_object, const char *my_format, ...) + __attribute__ ((format (printf, 2, 3))); +@end smallexample + +@noindent +causes the compiler to check the arguments in calls to @code{my_printf} +for consistency with the @code{printf} style format string argument +@code{my_format}. + +The parameter @var{archetype} determines how the format string is +interpreted, and should be @code{printf}, @code{scanf}, @code{strftime} +or @code{strfmon}. (You can also use @code{__printf__}, +@code{__scanf__}, @code{__strftime__} or @code{__strfmon__}.) The +parameter @var{string-index} specifies which argument is the format +string argument (starting from 1), while @var{first-to-check} is the +number of the first argument to check against the format string. For +functions where the arguments are not available to be checked (such as +@code{vprintf}), specify the third parameter as zero. In this case the +compiler only checks the format string for consistency. For +@code{strftime} formats, the third parameter is required to be zero. +Since non-static C++ methods have an implicit @code{this} argument, the +arguments of such methods should be counted from two, not one, when +giving values for @var{string-index} and @var{first-to-check}. + +In the example above, the format string (@code{my_format}) is the second +argument of the function @code{my_print}, and the arguments to check +start with the third argument, so the correct parameters for the format +attribute are 2 and 3. + +@opindex ffreestanding +@opindex fno-builtin +The @code{format} attribute allows you to identify your own functions +which take format strings as arguments, so that GCC can check the +calls to these functions for errors. The compiler always (unless +@option{-ffreestanding} or @option{-fno-builtin} is used) checks formats +for the standard library functions @code{printf}, @code{fprintf}, +@code{sprintf}, @code{scanf}, @code{fscanf}, @code{sscanf}, @code{strftime}, +@code{vprintf}, @code{vfprintf} and @code{vsprintf} whenever such +warnings are requested (using @option{-Wformat}), so there is no need to +modify the header file @file{stdio.h}. In C99 mode, the functions +@code{snprintf}, @code{vsnprintf}, @code{vscanf}, @code{vfscanf} and +@code{vsscanf} are also checked. Except in strictly conforming C +standard modes, the X/Open function @code{strfmon} is also checked as +are @code{printf_unlocked} and @code{fprintf_unlocked}. +@xref{C Dialect Options,,Options Controlling C Dialect}. + +The target may provide additional types of format checks. +@xref{Target Format Checks,,Format Checks Specific to Particular +Target Machines}. + +@item format_arg (@var{string-index}) +@cindex @code{format_arg} function attribute +@opindex Wformat-nonliteral +The @code{format_arg} attribute specifies that a function takes a format +string for a @code{printf}, @code{scanf}, @code{strftime} or +@code{strfmon} style function and modifies it (for example, to translate +it into another language), so the result can be passed to a +@code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style +function (with the remaining arguments to the format function the same +as they would have been for the unmodified string). For example, the +declaration: + +@smallexample +extern char * +my_dgettext (char *my_domain, const char *my_format) + __attribute__ ((format_arg (2))); +@end smallexample + +@noindent +causes the compiler to check the arguments in calls to a @code{printf}, +@code{scanf}, @code{strftime} or @code{strfmon} type function, whose +format string argument is a call to the @code{my_dgettext} function, for +consistency with the format string argument @code{my_format}. If the +@code{format_arg} attribute had not been specified, all the compiler +could tell in such calls to format functions would be that the format +string argument is not constant; this would generate a warning when +@option{-Wformat-nonliteral} is used, but the calls could not be checked +without the attribute. + +The parameter @var{string-index} specifies which argument is the format +string argument (starting from one). Since non-static C++ methods have +an implicit @code{this} argument, the arguments of such methods should +be counted from two. + +The @code{format-arg} attribute allows you to identify your own +functions which modify format strings, so that GCC can check the +calls to @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} +type function whose operands are a call to one of your own function. +The compiler always treats @code{gettext}, @code{dgettext}, and +@code{dcgettext} in this manner except when strict ISO C support is +requested by @option{-ansi} or an appropriate @option{-std} option, or +@option{-ffreestanding} or @option{-fno-builtin} +is used. @xref{C Dialect Options,,Options +Controlling C Dialect}. + +@item function_vector +@cindex calling functions through the function vector on the H8/300 processors +Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified +function should be called through the function vector. Calling a +function through the function vector will reduce code size, however; +the function vector has a limited size (maximum 128 entries on the H8/300 +and 64 entries on the H8/300H and H8S) and shares space with the interrupt vector. + +You must use GAS and GLD from GNU binutils version 2.7 or later for +this attribute to work correctly. + +@item interrupt +@cindex interrupt handler functions +Use this attribute on the ARM, AVR, C4x, CRX, M32C, M32R/D, MS1, and Xstormy16 +ports to indicate that the specified function is an interrupt handler. +The compiler will generate function entry and exit sequences suitable +for use in an interrupt handler when this attribute is present. + +Note, interrupt handlers for the Blackfin, m68k, H8/300, H8/300H, H8S, and +SH processors can be specified via the @code{interrupt_handler} attribute. + +Note, on the AVR, interrupts will be enabled inside the function. + +Note, for the ARM, you can specify the kind of interrupt to be handled by +adding an optional parameter to the interrupt attribute like this: + +@smallexample +void f () __attribute__ ((interrupt ("IRQ"))); +@end smallexample + +Permissible values for this parameter are: IRQ, FIQ, SWI, ABORT and UNDEF@. + +@item interrupt_handler +@cindex interrupt handler functions on the Blackfin, m68k, H8/300 and SH processors +Use this attribute on the Blackfin, m68k, H8/300, H8/300H, H8S, and SH to +indicate that the specified function is an interrupt handler. The compiler +will generate function entry and exit sequences suitable for use in an +interrupt handler when this attribute is present. + +@item kspisusp +@cindex User stack pointer in interrupts on the Blackfin +When used together with @code{interrupt_handler}, @code{exception_handler} +or @code{nmi_handler}, code will be generated to load the stack pointer +from the USP register in the function prologue. + +@c APPLE LOCAL prune man page +@ignore +@item long_call/short_call +@cindex indirect calls on ARM +This attribute specifies how a particular function is called on +ARM@. Both attributes override the @option{-mlong-calls} (@pxref{ARM Options}) +command line switch and @code{#pragma long_calls} settings. The +@code{long_call} attribute indicates that the function might be far +away from the call site and require a different (more expensive) +calling sequence. The @code{short_call} attribute always places +the offset to the function from the call site into the @samp{BL} +instruction directly. +@c APPLE LOCAL prune man page +@end ignore + +@item longcall/shortcall +@cindex functions called via pointer on the RS/6000 and PowerPC +On the Blackfin, RS/6000 and PowerPC, the @code{longcall} attribute +indicates that the function might be far away from the call site and +require a different (more expensive) calling sequence. The +@code{shortcall} attribute indicates that the function is always close +enough for the shorter calling sequence to be used. These attributes +override both the @option{-mlongcall} switch and, on the RS/6000 and +PowerPC, the @code{#pragma longcall} setting. + +@xref{RS/6000 and PowerPC Options}, for more information on whether long +calls are necessary. + +@c APPLE LOCAL prune man page +@ignore +@item long_call +@cindex indirect calls on MIPS +This attribute specifies how a particular function is called on MIPS@. +The attribute overrides the @option{-mlong-calls} (@pxref{MIPS Options}) +command line switch. This attribute causes the compiler to always call +the function by first loading its address into a register, and then using +the contents of that register. +@c APPLE LOCAL prune man page +@end ignore + +@item malloc +@cindex @code{malloc} attribute +The @code{malloc} attribute is used to tell the compiler that a function +may be treated as if any non-@code{NULL} pointer it returns cannot +alias any other pointer valid when the function returns. +This will often improve optimization. +Standard functions with this property include @code{malloc} and +@code{calloc}. @code{realloc}-like functions have this property as +long as the old pointer is never referred to (including comparing it +to the new pointer) after the function returns a non-@code{NULL} +value. + +@item model (@var{model-name}) +@cindex function addressability on the M32R/D +@cindex variable addressability on the IA-64 + +On the M32R/D, use this attribute to set the addressability of an +object, and of the code generated for a function. The identifier +@var{model-name} is one of @code{small}, @code{medium}, or +@code{large}, representing each of the code models. + +Small model objects live in the lower 16MB of memory (so that their +addresses can be loaded with the @code{ld24} instruction), and are +callable with the @code{bl} instruction. + +Medium model objects may live anywhere in the 32-bit address space (the +compiler will generate @code{seth/add3} instructions to load their addresses), +and are callable with the @code{bl} instruction. + +Large model objects may live anywhere in the 32-bit address space (the +compiler will generate @code{seth/add3} instructions to load their addresses), +and may not be reachable with the @code{bl} instruction (the compiler will +generate the much slower @code{seth/add3/jl} instruction sequence). + +On IA-64, use this attribute to set the addressability of an object. +At present, the only supported identifier for @var{model-name} is +@code{small}, indicating addressability via ``small'' (22-bit) +addresses (so that their addresses can be loaded with the @code{addl} +instruction). Caveat: such addressing is by definition not position +independent and hence this attribute must not be used for objects +defined by shared libraries. + +@item naked +@cindex function without a prologue/epilogue code +Use this attribute on the ARM, AVR, C4x and IP2K ports to indicate that the +specified function does not need prologue/epilogue sequences generated by +the compiler. It is up to the programmer to provide these sequences. + +@item near +@cindex functions which do not handle memory bank switching on 68HC11/68HC12 +On 68HC11 and 68HC12 the @code{near} attribute causes the compiler to +use the normal calling convention based on @code{jsr} and @code{rts}. +This attribute can be used to cancel the effect of the @option{-mlong-calls} +option. + +@item nesting +@cindex Allow nesting in an interrupt handler on the Blackfin processor. +Use this attribute together with @code{interrupt_handler}, +@code{exception_handler} or @code{nmi_handler} to indicate that the function +entry code should enable nested interrupts or exceptions. + +@item nmi_handler +@cindex NMI handler functions on the Blackfin processor +Use this attribute on the Blackfin to indicate that the specified function +is an NMI handler. The compiler will generate function entry and +exit sequences suitable for use in an NMI handler when this +attribute is present. + +@item no_instrument_function +@cindex @code{no_instrument_function} function attribute +@opindex finstrument-functions +If @option{-finstrument-functions} is given, profiling function calls will +be generated at entry and exit of most user-compiled functions. +Functions with this attribute will not be so instrumented. + +@item noinline +@cindex @code{noinline} function attribute +This function attribute prevents a function from being considered for +inlining. + +@item nonnull (@var{arg-index}, @dots{}) +@cindex @code{nonnull} function attribute +The @code{nonnull} attribute specifies that some function parameters should +be non-null pointers. For instance, the declaration: + +@smallexample +extern void * +my_memcpy (void *dest, const void *src, size_t len) + __attribute__((nonnull (1, 2))); +@end smallexample + +@noindent +causes the compiler to check that, in calls to @code{my_memcpy}, +arguments @var{dest} and @var{src} are non-null. If the compiler +determines that a null pointer is passed in an argument slot marked +as non-null, and the @option{-Wnonnull} option is enabled, a warning +is issued. The compiler may also choose to make optimizations based +on the knowledge that certain function arguments will not be null. + +If no argument index list is given to the @code{nonnull} attribute, +all pointer arguments are marked as non-null. To illustrate, the +following declaration is equivalent to the previous example: + +@smallexample +extern void * +my_memcpy (void *dest, const void *src, size_t len) + __attribute__((nonnull)); +@end smallexample + +@item noreturn +@cindex @code{noreturn} function attribute +A few standard library functions, such as @code{abort} and @code{exit}, +cannot return. GCC knows this automatically. Some programs define +their own functions that never return. You can declare them +@code{noreturn} to tell the compiler this fact. For example, + +@smallexample +@group +void fatal () __attribute__ ((noreturn)); + +void +fatal (/* @r{@dots{}} */) +@{ + /* @r{@dots{}} */ /* @r{Print error message.} */ /* @r{@dots{}} */ + exit (1); +@} +@end group +@end smallexample + +The @code{noreturn} keyword tells the compiler to assume that +@code{fatal} cannot return. It can then optimize without regard to what +would happen if @code{fatal} ever did return. This makes slightly +better code. More importantly, it helps avoid spurious warnings of +uninitialized variables. + +The @code{noreturn} keyword does not affect the exceptional path when that +applies: a @code{noreturn}-marked function may still return to the caller +by throwing an exception or calling @code{longjmp}. + +Do not assume that registers saved by the calling function are +restored before calling the @code{noreturn} function. + +It does not make sense for a @code{noreturn} function to have a return +type other than @code{void}. + +The attribute @code{noreturn} is not implemented in GCC versions +earlier than 2.5. An alternative way to declare that a function does +not return, which works in the current version and in some older +versions, is as follows: + +@smallexample +typedef void voidfn (); + +volatile voidfn fatal; +@end smallexample + +This approach does not work in GNU C++. + +@item nothrow +@cindex @code{nothrow} function attribute +The @code{nothrow} attribute is used to inform the compiler that a +function cannot throw an exception. For example, most functions in +the standard C library can be guaranteed not to throw an exception +with the notable exceptions of @code{qsort} and @code{bsearch} that +take function pointer arguments. The @code{nothrow} attribute is not +implemented in GCC versions earlier than 3.3. + +@item pure +@cindex @code{pure} function attribute +Many functions have no effects except the return value and their +return value depends only on the parameters and/or global variables. +Such a function can be subject +to common subexpression elimination and loop optimization just as an +arithmetic operator would be. These functions should be declared +with the attribute @code{pure}. For example, + +@smallexample +int square (int) __attribute__ ((pure)); +@end smallexample + +@noindent +says that the hypothetical function @code{square} is safe to call +fewer times than the program says. + +Some of common examples of pure functions are @code{strlen} or @code{memcmp}. +Interesting non-pure functions are functions with infinite loops or those +depending on volatile memory or other system resource, that may change between +two consecutive calls (such as @code{feof} in a multithreading environment). + +The attribute @code{pure} is not implemented in GCC versions earlier +than 2.96. + +@item regparm (@var{number}) +@cindex @code{regparm} attribute +@cindex functions that are passed arguments in registers on the 386 +On the Intel 386, the @code{regparm} attribute causes the compiler to +pass arguments number one to @var{number} if they are of integral type +in registers EAX, EDX, and ECX instead of on the stack. Functions that +take a variable number of arguments will continue to be passed all of their +arguments on the stack. + +Beware that on some ELF systems this attribute is unsuitable for +global functions in shared libraries with lazy binding (which is the +default). Lazy binding will send the first call via resolving code in +the loader, which might assume EAX, EDX and ECX can be clobbered, as +per the standard calling conventions. Solaris 8 is affected by this. +GNU systems with GLIBC 2.1 or higher, and FreeBSD, are believed to be +safe since the loaders there save all registers. (Lazy binding can be +disabled with the linker or the loader if desired, to avoid the +problem.) + +@item sseregparm +@cindex @code{sseregparm} attribute +On the Intel 386 with SSE support, the @code{sseregparm} attribute +causes the compiler to pass up to 3 floating point arguments in +SSE registers instead of on the stack. Functions that take a +variable number of arguments will continue to pass all of their +floating point arguments on the stack. + +@item force_align_arg_pointer +@cindex @code{force_align_arg_pointer} attribute +On the Intel x86, the @code{force_align_arg_pointer} attribute may be +applied to individual function definitions, generating an alternate +prologue and epilogue that realigns the runtime stack. This supports +mixing legacy codes that run with a 4-byte aligned stack with modern +codes that keep a 16-byte stack for SSE compatibility. The alternate +prologue and epilogue are slower and bigger than the regular ones, and +the alternate prologue requires a scratch register; this lowers the +number of registers available if used in conjunction with the +@code{regparm} attribute. The @code{force_align_arg_pointer} +attribute is incompatible with nested functions; this is considered a +hard error. + +@item returns_twice +@cindex @code{returns_twice} attribute +The @code{returns_twice} attribute tells the compiler that a function may +return more than one time. The compiler will ensure that all registers +are dead before calling such a function and will emit a warning about +the variables that may be clobbered after the second return from the +function. Examples of such functions are @code{setjmp} and @code{vfork}. +The @code{longjmp}-like counterpart of such function, if any, might need +to be marked with the @code{noreturn} attribute. + +@item saveall +@cindex save all registers on the Blackfin, H8/300, H8/300H, and H8S +Use this attribute on the Blackfin, H8/300, H8/300H, and H8S to indicate that +all registers except the stack pointer should be saved in the prologue +regardless of whether they are used or not. + +@item section ("@var{section-name}") +@cindex @code{section} function attribute +Normally, the compiler places the code it generates in the @code{text} section. +Sometimes, however, you need additional sections, or you need certain +particular functions to appear in special sections. The @code{section} +attribute specifies that a function lives in a particular section. +For example, the declaration: + +@smallexample +extern void foobar (void) __attribute__ ((section ("bar"))); +@end smallexample + +@noindent +puts the function @code{foobar} in the @code{bar} section. + +Some file formats do not support arbitrary sections so the @code{section} +attribute is not available on all platforms. +If you need to map the entire contents of a module to a particular +section, consider using the facilities of the linker instead. + +@item sentinel +@cindex @code{sentinel} function attribute +This function attribute ensures that a parameter in a function call is +an explicit @code{NULL}. The attribute is only valid on variadic +functions. By default, the sentinel is located at position zero, the +last parameter of the function call. If an optional integer position +argument P is supplied to the attribute, the sentinel must be located at +position P counting backwards from the end of the argument list. + +@smallexample +__attribute__ ((sentinel)) +is equivalent to +__attribute__ ((sentinel(0))) +@end smallexample + +The attribute is automatically set with a position of 0 for the built-in +functions @code{execl} and @code{execlp}. The built-in function +@code{execle} has the attribute set with a position of 1. + +A valid @code{NULL} in this context is defined as zero with any pointer +type. If your system defines the @code{NULL} macro with an integer type +then you need to add an explicit cast. GCC replaces @code{stddef.h} +with a copy that redefines NULL appropriately. + +The warnings for missing or incorrect sentinels are enabled with +@option{-Wformat}. + +@item short_call +See long_call/short_call. + +@item shortcall +See longcall/shortcall. + +@item signal +@cindex signal handler functions on the AVR processors +Use this attribute on the AVR to indicate that the specified +function is a signal handler. The compiler will generate function +entry and exit sequences suitable for use in a signal handler when this +attribute is present. Interrupts will be disabled inside the function. + +@c APPLE LOCAL begin regparmandstackparm +@item regparmandstackparm + +This is an X86_32-specific attribute. + +Two entry points will be created for this function. One will have the +traditional calling convention, and the other will have a mangled name +and a register-based calling convention. + +The register-based calling convention will pass up to four float or +double values in XMM registers, and up to two integral values in +integer registers. Long double values are still passed on the stack, +and functions returning long double will still use the x87 stacktop. + +Other modules linked with this function may use either entry point. +If a calling module has seen an extern declaration with the +@code{regparmandstackparm} attribute, it will call the register-based +entry point; otherwise, it will use the traditional entry point in the +usual way. + +When taking the address of a @code{regparmandstackparm} function, the +address of the traditional entry point will be used. Calls through +function pointers always use the traditional calling convention. + +The mangled name is currently created by appending ``$3SSE'' to the +original function name (before any C++ name-mangling), but users +should not rely upon this. + +The current implementation associates the original function body with +the register-based entry point. The traditional entry point will load +some registers from the stack and call the register-based entry point. +This means the traditional entry point will be slightly less efficient +than a function without the @code{regparmandstackparm} attribute, and the +generated code will be slightly larger. Depending upon sizes and +optimization levels, the inliner may inline the register-based body +into the traditional entry point; nothing is done to preclude this. +If the function was declared @code{static}, optimization may discard +the original entry point entirely. + +@smallexample +extern double __attribute__ ((regparmandstackparm)) my_cos (double d); +@end smallexample +@c APPLE LOCAL end regparmandstackparm + +@item sp_switch +Use this attribute on the SH to indicate an @code{interrupt_handler} +function should switch to an alternate stack. It expects a string +argument that names a global variable holding the address of the +alternate stack. + +@smallexample +void *alt_stack; +void f () __attribute__ ((interrupt_handler, + sp_switch ("alt_stack"))); +@end smallexample + +@item stdcall +@cindex functions that pop the argument stack on the 386 +On the Intel 386, the @code{stdcall} attribute causes the compiler to +assume that the called function will pop off the stack space used to +pass arguments, unless it takes a variable number of arguments. + +@item tiny_data +@cindex tiny data section on the H8/300H and H8S +Use this attribute on the H8/300H and H8S to indicate that the specified +variable should be placed into the tiny data section. +The compiler will generate more efficient code for loads and stores +on data in the tiny data section. Note the tiny data area is limited to +slightly under 32kbytes of data. + +@item trap_exit +Use this attribute on the SH for an @code{interrupt_handler} to return using +@code{trapa} instead of @code{rte}. This attribute expects an integer +argument specifying the trap number to be used. + +@item unused +@cindex @code{unused} attribute. +This attribute, attached to a function, means that the function is meant +to be possibly unused. GCC will not produce a warning for this +function. + +@item used +@cindex @code{used} attribute. +This attribute, attached to a function, means that code must be emitted +for the function even if it appears that the function is not referenced. +This is useful, for example, when the function is referenced only in +inline assembly. + +@item visibility ("@var{visibility_type}") +@cindex @code{visibility} attribute +This attribute affects the linkage of the declaration to which it is attached. +There are four supported @var{visibility_type} values: default, +hidden, protected or internal visibility. + +@smallexample +void __attribute__ ((visibility ("protected"))) +f () @{ /* @r{Do something.} */; @} +int i __attribute__ ((visibility ("hidden"))); +@end smallexample + +The possible values of @var{visibility_type} correspond to the +visibility settings in the ELF gABI. + +@table @dfn +@c keep this list of visibilities in alphabetical order. + +@item default +Default visibility is the normal case for the object file format. +This value is available for the visibility attribute to override other +options that may change the assumed visibility of entities. + +On ELF, default visibility means that the declaration is visible to other +modules and, in shared libraries, means that the declared entity may be +overridden. + +On Darwin, default visibility means that the declaration is visible to +other modules. + +Default visibility corresponds to ``external linkage'' in the language. + +@item hidden +Hidden visibility indicates that the entity declared will have a new +form of linkage, which we'll call ``hidden linkage''. Two +declarations of an object with hidden linkage refer to the same object +if they are in the same shared object. + +@item internal +Internal visibility is like hidden visibility, but with additional +processor specific semantics. Unless otherwise specified by the +psABI, GCC defines internal visibility to mean that a function is +@emph{never} called from another module. Compare this with hidden +functions which, while they cannot be referenced directly by other +modules, can be referenced indirectly via function pointers. By +indicating that a function cannot be called from outside the module, +GCC may for instance omit the load of a PIC register since it is known +that the calling function loaded the correct value. + +@item protected +Protected visibility is like default visibility except that it +indicates that references within the defining module will bind to the +definition in that module. That is, the declared entity cannot be +overridden by another module. + +@end table + +All visibilities are supported on many, but not all, ELF targets +(supported when the assembler supports the @samp{.visibility} +pseudo-op). Default visibility is supported everywhere. Hidden +visibility is supported on Darwin targets. + +The visibility attribute should be applied only to declarations which +would otherwise have external linkage. The attribute should be applied +consistently, so that the same entity should not be declared with +different settings of the attribute. + +In C++, the visibility attribute applies to types as well as functions +and objects, because in C++ types have linkage. A class must not have +greater visibility than its non-static data member types and bases, +and class members default to the visibility of their class. Also, a +declaration without explicit visibility is limited to the visibility +of its type. + +In C++, you can mark member functions and static member variables of a +class with the visibility attribute. This is useful if if you know a +particular method or static member variable should only be used from +one shared object; then you can mark it hidden while the rest of the +class has default visibility. Care must be taken to avoid breaking +the One Definition Rule; for example, it is usually not useful to mark +an inline method as hidden without marking the whole class as hidden. + +A C++ namespace declaration can also have the visibility attribute. +This attribute applies only to the particular namespace body, not to +other definitions of the same namespace; it is equivalent to using +@samp{#pragma GCC visibility} before and after the namespace +definition (@pxref{Visibility Pragmas}). + +In C++, if a template argument has limited visibility, this +restriction is implicitly propagated to the template instantiation. +Otherwise, template instantiations and specializations default to the +visibility of their template. + +If both the template and enclosing class have explicit visibility, the +visibility from the template is used. + +@item warn_unused_result +@cindex @code{warn_unused_result} attribute +The @code{warn_unused_result} attribute causes a warning to be emitted +if a caller of the function with this attribute does not use its +return value. This is useful for functions where not checking +the result is either a security problem or always a bug, such as +@code{realloc}. + +@smallexample +int fn () __attribute__ ((warn_unused_result)); +int foo () +@{ + if (fn () < 0) return -1; + fn (); + return 0; +@} +@end smallexample + +results in warning on line 5. + +@item weak +@cindex @code{weak} attribute +The @code{weak} attribute causes the declaration to be emitted as a weak +symbol rather than a global. This is primarily useful in defining +library functions which can be overridden in user code, though it can +also be used with non-function declarations. Weak symbols are supported +for ELF targets, and also for a.out targets when using the GNU assembler +and linker. + +@item weakref +@itemx weakref ("@var{target}") +@cindex @code{weakref} attribute +The @code{weakref} attribute marks a declaration as a weak reference. +Without arguments, it should be accompanied by an @code{alias} attribute +naming the target symbol. Optionally, the @var{target} may be given as +an argument to @code{weakref} itself. In either case, @code{weakref} +implicitly marks the declaration as @code{weak}. Without a +@var{target}, given as an argument to @code{weakref} or to @code{alias}, +@code{weakref} is equivalent to @code{weak}. + +@smallexample +static int x() __attribute__ ((weakref ("y"))); +/* is equivalent to... */ +static int x() __attribute__ ((weak, weakref, alias ("y"))); +/* and to... */ +static int x() __attribute__ ((weakref)); +static int x() __attribute__ ((alias ("y"))); +@end smallexample + +A weak reference is an alias that does not by itself require a +definition to be given for the target symbol. If the target symbol is +only referenced through weak references, then the becomes a @code{weak} +undefined symbol. If it is directly referenced, however, then such +strong references prevail, and a definition will be required for the +symbol, not necessarily in the same translation unit. + +The effect is equivalent to moving all references to the alias to a +separate translation unit, renaming the alias to the aliased symbol, +declaring it as weak, compiling the two separate translation units and +performing a reloadable link on them. + +At present, a declaration to which @code{weakref} is attached can +only be @code{static}. + +@item externally_visible +@cindex @code{externally_visible} attribute. +This attribute, attached to a global variable or function nullify +effect of @option{-fwhole-program} command line option, so the object +remain visible outside the current compilation unit + +@end table + +You can specify multiple attributes in a declaration by separating them +by commas within the double parentheses or by immediately following an +attribute declaration with another attribute declaration. + +@cindex @code{#pragma}, reason for not using +@cindex pragma, reason for not using +Some people object to the @code{__attribute__} feature, suggesting that +ISO C's @code{#pragma} should be used instead. At the time +@code{__attribute__} was designed, there were two reasons for not doing +this. + +@enumerate +@item +It is impossible to generate @code{#pragma} commands from a macro. + +@item +There is no telling what the same @code{#pragma} might mean in another +compiler. +@end enumerate + +These two reasons applied to almost any application that might have been +proposed for @code{#pragma}. It was basically a mistake to use +@code{#pragma} for @emph{anything}. + +The ISO C99 standard includes @code{_Pragma}, which now allows pragmas +to be generated from macros. In addition, a @code{#pragma GCC} +namespace is now in use for GCC-specific pragmas. However, it has been +found convenient to use @code{__attribute__} to achieve a natural +attachment of attributes to their corresponding declarations, whereas +@code{#pragma GCC} is of use for constructs that do not naturally form +part of the grammar. @xref{Other Directives,,Miscellaneous +Preprocessing Directives, cpp, The GNU C Preprocessor}. + +@node Attribute Syntax +@section Attribute Syntax +@cindex attribute syntax + +This section describes the syntax with which @code{__attribute__} may be +used, and the constructs to which attribute specifiers bind, for the C +language. Some details may vary for C++ and Objective-C@. Because of +infelicities in the grammar for attributes, some forms described here +may not be successfully parsed in all cases. + +There are some problems with the semantics of attributes in C++. For +example, there are no manglings for attributes, although they may affect +code generation, so problems may arise when attributed types are used in +conjunction with templates or overloading. Similarly, @code{typeid} +does not distinguish between types with different attributes. Support +for attributes in C++ may be restricted in future to attributes on +declarations only, but not on nested declarators. + +@xref{Function Attributes}, for details of the semantics of attributes +applying to functions. @xref{Variable Attributes}, for details of the +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +semantics of attributes applying to variables. @xref{Type +Attributes}, for details of the semantics of attributes applying to +structure, union and enumerated types. @xref{Label Attributes}, for +details of the semantics of attributes applying to labels and +statements. + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +An @dfn{attribute specifier} is of the form +@code{__attribute__ ((@var{attribute-list}))}. An @dfn{attribute list} +is a possibly empty comma-separated sequence of @dfn{attributes}, where +each attribute is one of the following: + +@itemize @bullet +@item +Empty. Empty attributes are ignored. + +@item +A word (which may be an identifier such as @code{unused}, or a reserved +word such as @code{const}). + +@item +A word, followed by, in parentheses, parameters for the attribute. +These parameters take one of the following forms: + +@itemize @bullet +@item +An identifier. For example, @code{mode} attributes use this form. + +@item +An identifier followed by a comma and a non-empty comma-separated list +of expressions. For example, @code{format} attributes use this form. + +@item +A possibly empty comma-separated list of expressions. For example, +@code{format_arg} attributes use this form with the list being a single +integer constant expression, and @code{alias} attributes use this form +with the list being a single string constant. +@end itemize +@end itemize + +An @dfn{attribute specifier list} is a sequence of one or more attribute +specifiers, not separated by any other tokens. + +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +In GNU C, an attribute specifier list may appear after the colon +following a label, other than a @code{case} or @code{default} label. +GNU C++ does not permit such placement of attribute lists, as it is +permissible for a declaration, which could begin with an attribute +list, to be labelled in C++. Declarations cannot be labelled in C90 +or C99, so the ambiguity does not arise there. + +In GNU C an attribute specifier list may also appear after the keyword +@code{while} in a while loop, after @code{do} and after @code{for}. + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +An attribute specifier list may appear as part of a @code{struct}, +@code{union} or @code{enum} specifier. It may go either immediately +after the @code{struct}, @code{union} or @code{enum} keyword, or after +the closing brace. The former syntax is preferred. +Where attribute specifiers follow the closing brace, they are considered +to relate to the structure, union or enumerated type defined, not to any +enclosing declaration the type specifier appears in, and the type +defined is not complete until after the attribute specifiers. +@c Otherwise, there would be the following problems: a shift/reduce +@c conflict between attributes binding the struct/union/enum and +@c binding to the list of specifiers/qualifiers; and "aligned" +@c attributes could use sizeof for the structure, but the size could be +@c changed later by "packed" attributes. + +Otherwise, an attribute specifier appears as part of a declaration, +counting declarations of unnamed parameters and type names, and relates +to that declaration (which may be nested in another declaration, for +example in the case of a parameter declaration), or to a particular declarator +within a declaration. Where an +attribute specifier is applied to a parameter declared as a function or +an array, it should apply to the function or array rather than the +pointer to which the parameter is implicitly converted, but this is not +yet correctly implemented. + +Any list of specifiers and qualifiers at the start of a declaration may +contain attribute specifiers, whether or not such a list may in that +context contain storage class specifiers. (Some attributes, however, +are essentially in the nature of storage class specifiers, and only make +sense where storage class specifiers may be used; for example, +@code{section}.) There is one necessary limitation to this syntax: the +first old-style parameter declaration in a function definition cannot +begin with an attribute specifier, because such an attribute applies to +the function instead by syntax described below (which, however, is not +yet implemented in this case). In some other cases, attribute +specifiers are permitted by this grammar but not yet supported by the +compiler. All attribute specifiers in this place relate to the +declaration as a whole. In the obsolescent usage where a type of +@code{int} is implied by the absence of type specifiers, such a list of +specifiers and qualifiers may be an attribute specifier list with no +other specifiers or qualifiers. + +At present, the first parameter in a function prototype must have some +type specifier which is not an attribute specifier; this resolves an +ambiguity in the interpretation of @code{void f(int +(__attribute__((foo)) x))}, but is subject to change. At present, if +the parentheses of a function declarator contain only attributes then +those attributes are ignored, rather than yielding an error or warning +or implying a single parameter of type int, but this is subject to +change. + +An attribute specifier list may appear immediately before a declarator +(other than the first) in a comma-separated list of declarators in a +declaration of more than one identifier using a single list of +specifiers and qualifiers. Such attribute specifiers apply +only to the identifier before whose declarator they appear. For +example, in + +@smallexample +__attribute__((noreturn)) void d0 (void), + __attribute__((format(printf, 1, 2))) d1 (const char *, ...), + d2 (void) +@end smallexample + +@noindent +the @code{noreturn} attribute applies to all the functions +declared; the @code{format} attribute only applies to @code{d1}. + +An attribute specifier list may appear immediately before the comma, +@code{=} or semicolon terminating the declaration of an identifier other +than a function definition. At present, such attribute specifiers apply +to the declared object or function, but in future they may attach to the +outermost adjacent declarator. In simple cases there is no difference, +but, for example, in + +@smallexample +void (****f)(void) __attribute__((noreturn)); +@end smallexample + +@noindent +at present the @code{noreturn} attribute applies to @code{f}, which +causes a warning since @code{f} is not a function, but in future it may +apply to the function @code{****f}. The precise semantics of what +attributes in such cases will apply to are not yet specified. Where an +assembler name for an object or function is specified (@pxref{Asm +Labels}), at present the attribute must follow the @code{asm} +specification; in future, attributes before the @code{asm} specification +may apply to the adjacent declarator, and those after it to the declared +object or function. + +An attribute specifier list may, in future, be permitted to appear after +the declarator in a function definition (before any old-style parameter +declarations or the function body). + +Attribute specifiers may be mixed with type qualifiers appearing inside +the @code{[]} of a parameter array declarator, in the C99 construct by +which such qualifiers are applied to the pointer to which the array is +implicitly converted. Such attribute specifiers apply to the pointer, +not to the array, but at present this is not implemented and they are +ignored. + +An attribute specifier list may appear at the start of a nested +declarator. At present, there are some limitations in this usage: the +attributes correctly apply to the declarator, but for most individual +attributes the semantics this implies are not implemented. +When attribute specifiers follow the @code{*} of a pointer +declarator, they may be mixed with any type qualifiers present. +The following describes the formal semantics of this syntax. It will make the +most sense if you are familiar with the formal specification of +declarators in the ISO C standard. + +Consider (as in C99 subclause 6.7.5 paragraph 4) a declaration @code{T +D1}, where @code{T} contains declaration specifiers that specify a type +@var{Type} (such as @code{int}) and @code{D1} is a declarator that +contains an identifier @var{ident}. The type specified for @var{ident} +for derived declarators whose type does not include an attribute +specifier is as in the ISO C standard. + +If @code{D1} has the form @code{( @var{attribute-specifier-list} D )}, +and the declaration @code{T D} specifies the type +``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then +@code{T D1} specifies the type ``@var{derived-declarator-type-list} +@var{attribute-specifier-list} @var{Type}'' for @var{ident}. + +If @code{D1} has the form @code{* +@var{type-qualifier-and-attribute-specifier-list} D}, and the +declaration @code{T D} specifies the type +``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then +@code{T D1} specifies the type ``@var{derived-declarator-type-list} +@var{type-qualifier-and-attribute-specifier-list} @var{Type}'' for +@var{ident}. + +For example, + +@smallexample +void (__attribute__((noreturn)) ****f) (void); +@end smallexample + +@noindent +specifies the type ``pointer to pointer to pointer to pointer to +non-returning function returning @code{void}''. As another example, + +@smallexample +char *__attribute__((aligned(8))) *f; +@end smallexample + +@noindent +specifies the type ``pointer to 8-byte-aligned pointer to @code{char}''. +Note again that this does not work with most attributes; for example, +the usage of @samp{aligned} and @samp{noreturn} attributes given above +is not yet supported. + +For compatibility with existing code written for compiler versions that +did not implement attributes on nested declarators, some laxity is +allowed in the placing of attributes. If an attribute that only applies +to types is applied to a declaration, it will be treated as applying to +the type of that declaration. If an attribute that only applies to +declarations is applied to the type of a declaration, it will be treated +as applying to that declaration; and, for compatibility with code +placing the attributes immediately before the identifier declared, such +an attribute applied to a function return type will be treated as +applying to the function type, and such an attribute applied to an array +element type will be treated as applying to the array type. If an +attribute that only applies to function types is applied to a +pointer-to-function type, it will be treated as applying to the pointer +target type; if such an attribute is applied to a function return type +that is not a pointer-to-function type, it will be treated as applying +to the function type. + +@node Function Prototypes +@section Prototypes and Old-Style Function Definitions +@cindex function prototype declarations +@cindex old-style function definitions +@cindex promotion of formal parameters + +GNU C extends ISO C to allow a function prototype to override a later +old-style non-prototype definition. Consider the following example: + +@smallexample +/* @r{Use prototypes unless the compiler is old-fashioned.} */ +#ifdef __STDC__ +#define P(x) x +#else +#define P(x) () +#endif + +/* @r{Prototype function declaration.} */ +int isroot P((uid_t)); + +/* @r{Old-style function definition.} */ +int +isroot (x) /* @r{??? lossage here ???} */ + uid_t x; +@{ + return x == 0; +@} +@end smallexample + +Suppose the type @code{uid_t} happens to be @code{short}. ISO C does +not allow this example, because subword arguments in old-style +non-prototype definitions are promoted. Therefore in this example the +function definition's argument is really an @code{int}, which does not +match the prototype argument type of @code{short}. + +This restriction of ISO C makes it hard to write code that is portable +to traditional C compilers, because the programmer does not know +whether the @code{uid_t} type is @code{short}, @code{int}, or +@code{long}. Therefore, in cases like these GNU C allows a prototype +to override a later old-style definition. More precisely, in GNU C, a +function prototype argument type overrides the argument type specified +by a later old-style definition if the former type is the same as the +latter type before promotion. Thus in GNU C the above example is +equivalent to the following: + +@smallexample +int isroot (uid_t); + +int +isroot (uid_t x) +@{ + return x == 0; +@} +@end smallexample + +@noindent +GNU C++ does not support old-style function definitions, so this +extension is irrelevant. + +@node C++ Comments +@section C++ Style Comments +@cindex // +@cindex C++ comments +@cindex comments, C++ style + +In GNU C, you may use C++ style comments, which start with @samp{//} and +continue until the end of the line. Many other C implementations allow +such comments, and they are included in the 1999 C standard. However, +C++ style comments are not recognized if you specify an @option{-std} +option specifying a version of ISO C before C99, or @option{-ansi} +(equivalent to @option{-std=c89}). + +@node Dollar Signs +@section Dollar Signs in Identifier Names +@cindex $ +@cindex dollar signs in identifier names +@cindex identifier names, dollar signs in + +In GNU C, you may normally use dollar signs in identifier names. +This is because many traditional C implementations allow such identifiers. +However, dollar signs in identifiers are not supported on a few target +machines, typically because the target assembler does not allow them. + +@node Character Escapes +@section The Character @key{ESC} in Constants + +You can use the sequence @samp{\e} in a string or character constant to +stand for the ASCII character @key{ESC}. + +@c APPLE LOCAL begin pascal strings +@node Pascal Strings +@section Constructing String Literals with a Pascal-style Length Byte +@cindex Pascal length byte +@cindex Pascal strings + +Specifying the @w{@option{-fpascal-strings}} option will cause the +compiler to recognize and construct Pascal-style string literals. This +functionality is disabled by default; furthermore, its use in new code +is discouraged. + +Pascal string literals take the form @samp{"\pstring"}. The special +escape sequence @samp{\p} denotes the Pascal length byte for the string, +and will be replaced at compile time with the number of characters that +follow. The @samp{\p} may only appear at the beginning of a string +literal, and may @emph{not} appear in wide string literals or as an +integral constant. + +As is the case with C string literals, Pascal string literals are +terminated with a NUL character; this character is @emph{not} counted +when computing the value of the length byte. The maximum @samp{unsigned +char} value that can be stored in the length byte is also the maximum +permissible length for the Pascal literal itself. On most target +platforms, this value is 255 (excluding both the length byte and the +terminating NUL). + +Pascal-style literals are treated by the compiler as being of type +@samp{const unsigned char []} in C++ and @samp{unsigned char []} (or +@samp{const unsigned char []}, if the @w{@option{-Wwrite-strings}} +option is given) in C. Pascal string literals may be used as static +initializers for @samp{char} arrays (whose elements need not be +@samp{unsigned} or @samp{const}). They may also be converted to +@samp{const unsigned char *} and, in the C language to @samp{const char +*} of any signedness (In C, if the @w{@option{-Wwrite-strings}} is not +given, then @samp{const} may be omitted as well). For example: + +@example +const unsigned char a[] = "\pHello"; +char b[] = "\pGoodbye"; +const unsigned char *c = "\pHello"; +const signed char *d = "\pHello"; /* error in C++ */ +char *e = "\pHi"; /* error in C++; warning in C with -Wwrite-strings */ +unsigned char *f = "\pHello"; /* error in C++ */ +@end example + +@noindent +In all other respects, Pascal-style string literals behave the same as +ordinary string literals. For example, if a program attempts to modify +the conents of a Pascal-style string literal at run-time, the behaviour +is undefined, unless the @w{@option{-fwritable-strings}} option is used. + +Pascal-style literals are useful for calling external routines that +expect Pascal strings as arguments, as is true with some Apple MacOS +Toolbox calls. +@c APPLE LOCAL end pascal strings + +@node Alignment +@section Inquiring on Alignment of Types or Variables +@cindex alignment +@cindex type alignment +@cindex variable alignment + +The keyword @code{__alignof__} allows you to inquire about how an object +is aligned, or the minimum alignment usually required by a type. Its +syntax is just like @code{sizeof}. + +For example, if the target machine requires a @code{double} value to be +aligned on an 8-byte boundary, then @code{__alignof__ (double)} is 8. +This is true on many RISC machines. On more traditional machine +designs, @code{__alignof__ (double)} is 4 or even 2. + +Some machines never actually require alignment; they allow reference to any +data type even at an odd address. For these machines, @code{__alignof__} +reports the @emph{recommended} alignment of a type. + +If the operand of @code{__alignof__} is an lvalue rather than a type, +its value is the required alignment for its type, taking into account +any minimum alignment specified with GCC's @code{__attribute__} +extension (@pxref{Variable Attributes}). For example, after this +declaration: + +@smallexample +struct foo @{ int x; char y; @} foo1; +@end smallexample + +@noindent +the value of @code{__alignof__ (foo1.y)} is 1, even though its actual +alignment is probably 2 or 4, the same as @code{__alignof__ (int)}. + +It is an error to ask for the alignment of an incomplete type. + +@node Variable Attributes +@section Specifying Attributes of Variables +@cindex attribute of variables +@cindex variable attributes + +The keyword @code{__attribute__} allows you to specify special +attributes of variables or structure fields. This keyword is followed +by an attribute specification inside double parentheses. Some +attributes are currently defined generically for variables. +Other attributes are defined for variables on particular target +systems. Other attributes are available for functions +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +(@pxref{Function Attributes}), types (@pxref{Type Attributes}) and +labels (@pxref{Label Attributes}). Other front ends might define +more attributes (@pxref{C++ Extensions,,Extensions to the C++ Language}). + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +You may also specify attributes with @samp{__} preceding and following +each keyword. This allows you to use them in header files without +being concerned about a possible macro of the same name. For example, +you may use @code{__aligned__} instead of @code{aligned}. + +@xref{Attribute Syntax}, for details of the exact syntax for using +attributes. + +@table @code +@cindex @code{aligned} attribute +@item aligned (@var{alignment}) +This attribute specifies a minimum alignment for the variable or +structure field, measured in bytes. For example, the declaration: + +@smallexample +int x __attribute__ ((aligned (16))) = 0; +@end smallexample + +@noindent +causes the compiler to allocate the global variable @code{x} on a +16-byte boundary. On a 68040, this could be used in conjunction with +an @code{asm} expression to access the @code{move16} instruction which +requires 16-byte aligned operands. + +You can also specify the alignment of structure fields. For example, to +create a double-word aligned @code{int} pair, you could write: + +@smallexample +struct foo @{ int x[2] __attribute__ ((aligned (8))); @}; +@end smallexample + +@noindent +This is an alternative to creating a union with a @code{double} member +that forces the union to be double-word aligned. + +As in the preceding examples, you can explicitly specify the alignment +(in bytes) that you wish the compiler to use for a given variable or +structure field. Alternatively, you can leave out the alignment factor +and just ask the compiler to align a variable or field to the maximum +useful alignment for the target machine you are compiling for. For +example, you could write: + +@smallexample +short array[3] __attribute__ ((aligned)); +@end smallexample + +Whenever you leave out the alignment factor in an @code{aligned} attribute +specification, the compiler automatically sets the alignment for the declared +variable or field to the largest alignment which is ever used for any data +type on the target machine you are compiling for. Doing this can often make +copy operations more efficient, because the compiler can use whatever +instructions copy the biggest chunks of memory when performing copies to +or from the variables or fields that you have aligned this way. + +The @code{aligned} attribute can only increase the alignment; but you +can decrease it by specifying @code{packed} as well. See below. + +Note that the effectiveness of @code{aligned} attributes may be limited +by inherent limitations in your linker. On many systems, the linker is +only able to arrange for variables to be aligned up to a certain maximum +alignment. (For some linkers, the maximum supported alignment may +be very very small.) If your linker is only able to align variables +up to a maximum of 8 byte alignment, then specifying @code{aligned(16)} +in an @code{__attribute__} will still only provide you with 8 byte +alignment. See your linker documentation for further information. + +@c APPLE LOCAL begin aligned functions 5933878 +The @code{aligned} attribute can also be used for functions +(@pxref{Function Attributes}.) +@c APPLE LOCAL end aligned functions 5933878 + +@item cleanup (@var{cleanup_function}) +@cindex @code{cleanup} attribute +The @code{cleanup} attribute runs a function when the variable goes +out of scope. This attribute can only be applied to auto function +scope variables; it may not be applied to parameters or variables +with static storage duration. The function must take one parameter, +a pointer to a type compatible with the variable. The return value +of the function (if any) is ignored. + +If @option{-fexceptions} is enabled, then @var{cleanup_function} +will be run during the stack unwinding that happens during the +processing of the exception. Note that the @code{cleanup} attribute +does not allow the exception to be caught, only to perform an action. +It is undefined what happens if @var{cleanup_function} does not +return normally. + +@item common +@itemx nocommon +@cindex @code{common} attribute +@cindex @code{nocommon} attribute +@opindex fcommon +@opindex fno-common +The @code{common} attribute requests GCC to place a variable in +``common'' storage. The @code{nocommon} attribute requests the +opposite---to allocate space for it directly. + +These attributes override the default chosen by the +@option{-fno-common} and @option{-fcommon} flags respectively. + +@item deprecated +@cindex @code{deprecated} attribute +The @code{deprecated} attribute results in a warning if the variable +is used anywhere in the source file. This is useful when identifying +variables that are expected to be removed in a future version of a +program. The warning also includes the location of the declaration +of the deprecated variable, to enable users to easily find further +information about why the variable is deprecated, or what they should +do instead. Note that the warning only occurs for uses: + +@smallexample +extern int old_var __attribute__ ((deprecated)); +extern int old_var; +int new_fn () @{ return old_var; @} +@end smallexample + +results in a warning on line 3 but not line 2. + +The @code{deprecated} attribute can also be used for functions and +types (@pxref{Function Attributes}, @pxref{Type Attributes}.) + +@item mode (@var{mode}) +@cindex @code{mode} attribute +This attribute specifies the data type for the declaration---whichever +type corresponds to the mode @var{mode}. This in effect lets you +request an integer or floating point type according to its width. + +You may also specify a mode of @samp{byte} or @samp{__byte__} to +indicate the mode corresponding to a one-byte integer, @samp{word} or +@samp{__word__} for the mode of a one-word integer, and @samp{pointer} +or @samp{__pointer__} for the mode used to represent pointers. + +@item packed +@cindex @code{packed} attribute +The @code{packed} attribute specifies that a variable or structure field +should have the smallest possible alignment---one byte for a variable, +and one bit for a field, unless you specify a larger value with the +@code{aligned} attribute. + +Here is a structure in which the field @code{x} is packed, so that it +immediately follows @code{a}: + +@smallexample +struct foo +@{ + char a; + int x[2] __attribute__ ((packed)); +@}; +@end smallexample + +@item section ("@var{section-name}") +@cindex @code{section} variable attribute +Normally, the compiler places the objects it generates in sections like +@code{data} and @code{bss}. Sometimes, however, you need additional sections, +or you need certain particular variables to appear in special sections, +for example to map to special hardware. The @code{section} +attribute specifies that a variable (or function) lives in a particular +section. For example, this small program uses several specific section names: + +@smallexample +struct duart a __attribute__ ((section ("DUART_A"))) = @{ 0 @}; +struct duart b __attribute__ ((section ("DUART_B"))) = @{ 0 @}; +char stack[10000] __attribute__ ((section ("STACK"))) = @{ 0 @}; +int init_data __attribute__ ((section ("INITDATA"))) = 0; + +main() +@{ + /* @r{Initialize stack pointer} */ + init_sp (stack + sizeof (stack)); + + /* @r{Initialize initialized data} */ + memcpy (&init_data, &data, &edata - &data); + + /* @r{Turn on the serial ports} */ + init_duart (&a); + init_duart (&b); +@} +@end smallexample + +@noindent +Use the @code{section} attribute with an @emph{initialized} definition +of a @emph{global} variable, as shown in the example. GCC issues +a warning and otherwise ignores the @code{section} attribute in +uninitialized variable declarations. + +You may only use the @code{section} attribute with a fully initialized +global definition because of the way linkers work. The linker requires +each object be defined once, with the exception that uninitialized +variables tentatively go in the @code{common} (or @code{bss}) section +and can be multiply ``defined''. You can force a variable to be +initialized with the @option{-fno-common} flag or the @code{nocommon} +attribute. + +Some file formats do not support arbitrary sections so the @code{section} +attribute is not available on all platforms. +If you need to map the entire contents of a module to a particular +section, consider using the facilities of the linker instead. + +@item shared +@cindex @code{shared} variable attribute +On Microsoft Windows, in addition to putting variable definitions in a named +section, the section can also be shared among all running copies of an +executable or DLL@. For example, this small program defines shared data +by putting it in a named section @code{shared} and marking the section +shareable: + +@smallexample +int foo __attribute__((section ("shared"), shared)) = 0; + +int +main() +@{ + /* @r{Read and write foo. All running + copies see the same value.} */ + return 0; +@} +@end smallexample + +@noindent +You may only use the @code{shared} attribute along with @code{section} +attribute with a fully initialized global definition because of the way +linkers work. See @code{section} attribute for more information. + +The @code{shared} attribute is only available on Microsoft Windows@. + +@item tls_model ("@var{tls_model}") +@cindex @code{tls_model} attribute +The @code{tls_model} attribute sets thread-local storage model +(@pxref{Thread-Local}) of a particular @code{__thread} variable, +overriding @option{-ftls-model=} command line switch on a per-variable +basis. +The @var{tls_model} argument should be one of @code{global-dynamic}, +@code{local-dynamic}, @code{initial-exec} or @code{local-exec}. + +Not all targets support this attribute. + +@item unused +This attribute, attached to a variable, means that the variable is meant +to be possibly unused. GCC will not produce a warning for this +variable. + +@item used +This attribute, attached to a variable, means that the variable must be +emitted even if it appears that the variable is not referenced. + +@item vector_size (@var{bytes}) +This attribute specifies the vector size for the variable, measured in +bytes. For example, the declaration: + +@smallexample +int foo __attribute__ ((vector_size (16))); +@end smallexample + +@noindent +causes the compiler to set the mode for @code{foo}, to be 16 bytes, +divided into @code{int} sized units. Assuming a 32-bit int (a vector of +4 units of 4 bytes), the corresponding mode of @code{foo} will be V4SI@. + +This attribute is only applicable to integral and float scalars, +although arrays, pointers, and function return values are allowed in +conjunction with this construct. + +Aggregates with this attribute are invalid, even if they are of the same +size as a corresponding scalar. For example, the declaration: + +@smallexample +struct S @{ int a; @}; +struct S __attribute__ ((vector_size (16))) foo; +@end smallexample + +@noindent +is invalid even if the size of the structure is the same as the size of +the @code{int}. + +@item selectany +The @code{selectany} attribute causes an initialized global variable to +have link-once semantics. When multiple definitions of the variable are +encountered by the linker, the first is selected and the remainder are +discarded. Following usage by the Microsoft compiler, the linker is told +@emph{not} to warn about size or content differences of the multiple +definitions. + +Although the primary usage of this attribute is for POD types, the +attribute can also be applied to global C++ objects that are initialized +by a constructor. In this case, the static initialization and destruction +code for the object is emitted in each translation defining the object, +but the calls to the constructor and destructor are protected by a +link-once guard variable. + +The @code{selectany} attribute is only available on Microsoft Windows +targets. You can use @code{__declspec (selectany)} as a synonym for +@code{__attribute__ ((selectany))} for compatibility with other +compilers. + +@item weak +The @code{weak} attribute is described in @xref{Function Attributes}. + +@item dllimport +The @code{dllimport} attribute is described in @xref{Function Attributes}. + +@item dllexport +The @code{dllexport} attribute is described in @xref{Function Attributes}. + +@end table + +@subsection M32R/D Variable Attributes + +One attribute is currently defined for the M32R/D@. + +@table @code +@item model (@var{model-name}) +@cindex variable addressability on the M32R/D +Use this attribute on the M32R/D to set the addressability of an object. +The identifier @var{model-name} is one of @code{small}, @code{medium}, +or @code{large}, representing each of the code models. + +Small model objects live in the lower 16MB of memory (so that their +addresses can be loaded with the @code{ld24} instruction). + +Medium and large model objects may live anywhere in the 32-bit address space +(the compiler will generate @code{seth/add3} instructions to load their +addresses). +@end table + +@c APPLE LOCAL begin 5946347 ms_struct support +@anchor{PowerPC Variable Attributes} +@subsection PowerPC Variable Attributes + +One is defined for PowerPC configurations: @code{altivec}. + +For documentation of the @code{altivec} attribute please see the +documentation in the @xref{PowerPC Type Attributes}, section. +@c APPLE LOCAL end 5946347 ms_struct support + +@subsection Xstormy16 Variable Attributes + +One attribute is currently defined for xstormy16 configurations: +@code{below100} + +@table @code +@item below100 +@cindex @code{below100} attribute + +If a variable has the @code{below100} attribute (@code{BELOW100} is +allowed also), GCC will place the variable in the first 0x100 bytes of +memory and use special opcodes to access it. Such variables will be +placed in either the @code{.bss_below100} section or the +@code{.data_below100} section. + +@end table + +@node Type Attributes +@section Specifying Attributes of Types +@cindex attribute of types +@cindex type attributes + +The keyword @code{__attribute__} allows you to specify special +attributes of @code{struct} and @code{union} types when you define +such types. This keyword is followed by an attribute specification +inside double parentheses. Seven attributes are currently defined for +types: @code{aligned}, @code{packed}, @code{transparent_union}, +@code{unused}, @code{deprecated}, @code{visibility}, and +@code{may_alias}. Other attributes are defined for functions +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +(@pxref{Function Attributes}), variables (@pxref{Variable +Attributes}), and labels (@pxref{Label Attributes}). + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +You may also specify any one of these attributes with @samp{__} +preceding and following its keyword. This allows you to use these +attributes in header files without being concerned about a possible +macro of the same name. For example, you may use @code{__aligned__} +instead of @code{aligned}. + +You may specify type attributes either in a @code{typedef} declaration +or in an enum, struct or union type declaration or definition. + +For an enum, struct or union type, you may specify attributes either +between the enum, struct or union tag and the name of the type, or +just past the closing curly brace of the @emph{definition}. The +former syntax is preferred. + +@xref{Attribute Syntax}, for details of the exact syntax for using +attributes. + +@table @code +@cindex @code{aligned} attribute +@item aligned (@var{alignment}) +This attribute specifies a minimum alignment (in bytes) for variables +of the specified type. For example, the declarations: + +@smallexample +struct S @{ short f[3]; @} __attribute__ ((aligned (8))); +typedef int more_aligned_int __attribute__ ((aligned (8))); +@end smallexample + +@noindent +force the compiler to insure (as far as it can) that each variable whose +type is @code{struct S} or @code{more_aligned_int} will be allocated and +aligned @emph{at least} on a 8-byte boundary. On a SPARC, having all +variables of type @code{struct S} aligned to 8-byte boundaries allows +the compiler to use the @code{ldd} and @code{std} (doubleword load and +store) instructions when copying one variable of type @code{struct S} to +another, thus improving run-time efficiency. + +Note that the alignment of any given @code{struct} or @code{union} type +is required by the ISO C standard to be at least a perfect multiple of +the lowest common multiple of the alignments of all of the members of +the @code{struct} or @code{union} in question. This means that you @emph{can} +effectively adjust the alignment of a @code{struct} or @code{union} +type by attaching an @code{aligned} attribute to any one of the members +of such a type, but the notation illustrated in the example above is a +more obvious, intuitive, and readable way to request the compiler to +adjust the alignment of an entire @code{struct} or @code{union} type. + +As in the preceding example, you can explicitly specify the alignment +(in bytes) that you wish the compiler to use for a given @code{struct} +or @code{union} type. Alternatively, you can leave out the alignment factor +and just ask the compiler to align a type to the maximum +useful alignment for the target machine you are compiling for. For +example, you could write: + +@smallexample +struct S @{ short f[3]; @} __attribute__ ((aligned)); +@end smallexample + +Whenever you leave out the alignment factor in an @code{aligned} +attribute specification, the compiler automatically sets the alignment +for the type to the largest alignment which is ever used for any data +type on the target machine you are compiling for. Doing this can often +make copy operations more efficient, because the compiler can use +whatever instructions copy the biggest chunks of memory when performing +copies to or from the variables which have types that you have aligned +this way. + +In the example above, if the size of each @code{short} is 2 bytes, then +the size of the entire @code{struct S} type is 6 bytes. The smallest +power of two which is greater than or equal to that is 8, so the +compiler sets the alignment for the entire @code{struct S} type to 8 +bytes. + +Note that although you can ask the compiler to select a time-efficient +alignment for a given type and then declare only individual stand-alone +objects of that type, the compiler's ability to select a time-efficient +alignment is primarily useful only when you plan to create arrays of +variables having the relevant (efficiently aligned) type. If you +declare or use arrays of variables of an efficiently-aligned type, then +it is likely that your program will also be doing pointer arithmetic (or +subscripting, which amounts to the same thing) on pointers to the +relevant type, and the code that the compiler generates for these +pointer arithmetic operations will often be more efficient for +efficiently-aligned types than for other types. + +The @code{aligned} attribute can only increase the alignment; but you +can decrease it by specifying @code{packed} as well. See below. + +Note that the effectiveness of @code{aligned} attributes may be limited +by inherent limitations in your linker. On many systems, the linker is +only able to arrange for variables to be aligned up to a certain maximum +alignment. (For some linkers, the maximum supported alignment may +be very very small.) If your linker is only able to align variables +up to a maximum of 8 byte alignment, then specifying @code{aligned(16)} +in an @code{__attribute__} will still only provide you with 8 byte +alignment. See your linker documentation for further information. + +@item packed +This attribute, attached to @code{struct} or @code{union} type +definition, specifies that each member (other than zero-width bitfields) +of the structure or union is placed to minimize the memory required. When +attached to an @code{enum} definition, it indicates that the smallest +integral type should be used. + +@opindex fshort-enums +Specifying this attribute for @code{struct} and @code{union} types is +equivalent to specifying the @code{packed} attribute on each of the +structure or union members. Specifying the @option{-fshort-enums} +flag on the line is equivalent to specifying the @code{packed} +attribute on all @code{enum} definitions. + +In the following example @code{struct my_packed_struct}'s members are +packed closely together, but the internal layout of its @code{s} member +is not packed---to do that, @code{struct my_unpacked_struct} would need to +be packed too. + +@smallexample +struct my_unpacked_struct + @{ + char c; + int i; + @}; + +struct __attribute__ ((__packed__)) my_packed_struct + @{ + char c; + int i; + struct my_unpacked_struct s; + @}; +@end smallexample + +You may only specify this attribute on the definition of a @code{enum}, +@code{struct} or @code{union}, not on a @code{typedef} which does not +also define the enumerated type, structure or union. + +@item transparent_union +This attribute, attached to a @code{union} type definition, indicates +that any function parameter having that union type causes calls to that +function to be treated in a special way. + +First, the argument corresponding to a transparent union type can be of +any type in the union; no cast is required. Also, if the union contains +a pointer type, the corresponding argument can be a null pointer +constant or a void pointer expression; and if the union contains a void +pointer type, the corresponding argument can be any pointer expression. +If the union member type is a pointer, qualifiers like @code{const} on +the referenced type must be respected, just as with normal pointer +conversions. + +Second, the argument is passed to the function using the calling +conventions of the first member of the transparent union, not the calling +conventions of the union itself. All members of the union must have the +same machine representation; this is necessary for this argument passing +to work properly. + +Transparent unions are designed for library functions that have multiple +interfaces for compatibility reasons. For example, suppose the +@code{wait} function must accept either a value of type @code{int *} to +comply with Posix, or a value of type @code{union wait *} to comply with +the 4.1BSD interface. If @code{wait}'s parameter were @code{void *}, +@code{wait} would accept both kinds of arguments, but it would also +accept any other pointer type and this would make argument type checking +less useful. Instead, @code{<sys/wait.h>} might define the interface +as follows: + +@smallexample +typedef union + @{ + int *__ip; + union wait *__up; + @} wait_status_ptr_t __attribute__ ((__transparent_union__)); + +pid_t wait (wait_status_ptr_t); +@end smallexample + +This interface allows either @code{int *} or @code{union wait *} +arguments to be passed, using the @code{int *} calling convention. +The program can call @code{wait} with arguments of either type: + +@smallexample +int w1 () @{ int w; return wait (&w); @} +int w2 () @{ union wait w; return wait (&w); @} +@end smallexample + +With this interface, @code{wait}'s implementation might look like this: + +@smallexample +pid_t wait (wait_status_ptr_t p) +@{ + return waitpid (-1, p.__ip, 0); +@} +@end smallexample + +@item unused +When attached to a type (including a @code{union} or a @code{struct}), +this attribute means that variables of that type are meant to appear +possibly unused. GCC will not produce a warning for any variables of +that type, even if the variable appears to do nothing. This is often +the case with lock or thread classes, which are usually defined and then +not referenced, but contain constructors and destructors that have +nontrivial bookkeeping functions. + +@item deprecated +The @code{deprecated} attribute results in a warning if the type +is used anywhere in the source file. This is useful when identifying +types that are expected to be removed in a future version of a program. +If possible, the warning also includes the location of the declaration +of the deprecated type, to enable users to easily find further +information about why the type is deprecated, or what they should do +instead. Note that the warnings only occur for uses and then only +if the type is being applied to an identifier that itself is not being +declared as deprecated. + +@smallexample +typedef int T1 __attribute__ ((deprecated)); +T1 x; +typedef T1 T2; +T2 y; +typedef T1 T3 __attribute__ ((deprecated)); +T3 z __attribute__ ((deprecated)); +@end smallexample + +results in a warning on line 2 and 3 but not lines 4, 5, or 6. No +warning is issued for line 4 because T2 is not explicitly +deprecated. Line 5 has no warning because T3 is explicitly +deprecated. Similarly for line 6. + +The @code{deprecated} attribute can also be used for functions and +variables (@pxref{Function Attributes}, @pxref{Variable Attributes}.) + +@item may_alias +Accesses to objects with types with this attribute are not subjected to +type-based alias analysis, but are instead assumed to be able to alias +any other type of objects, just like the @code{char} type. See +@option{-fstrict-aliasing} for more information on aliasing issues. + +Example of use: + +@smallexample +typedef short __attribute__((__may_alias__)) short_a; + +int +main (void) +@{ + int a = 0x12345678; + short_a *b = (short_a *) &a; + + b[1] = 0; + + if (a == 0x12345678) + abort(); + + exit(0); +@} +@end smallexample + +If you replaced @code{short_a} with @code{short} in the variable +declaration, the above program would abort when compiled with +@option{-fstrict-aliasing}, which is on by default at @option{-O2} or +above in recent GCC versions. + +@item visibility +In C++, attribute visibility (@pxref{Function Attributes}) can also be +applied to class, struct, union and enum types. Unlike other type +attributes, the attribute must appear between the initial keyword and +the name of the type; it cannot appear after the body of the type. + +Note that the type visibility is applied to vague linkage entities +associated with the class (vtable, typeinfo node, etc.). In +particular, if a class is thrown as an exception in one shared object +and caught in another, the class must have default visibility. +Otherwise the two shared objects will be unable to use the same +typeinfo node and exception handling will break. + +@c APPLE LOCAL begin weak types 5954418 +@item weak +In C++, attribute weak can be applied to a class to ensure that all +non-hidden instances of the type are treated as the same type across +shared library boundaries on platforms (such as darwin and arm aapcs) +that can emit vtables and the type info meta data as non-comdat +symbols. This is useful when the class has a key method and the +translation unit that contains the key method is used in more than one +shared library or in a shared library and the application. Doing this +results in more expensive startup times. This attribute is inherited +by subclasses, so it is only necessary to mark a base type. The +typical use would be to mark any types used for throwing across shared +library boundaries or those used in dynamic_cast operations across a +shared library boundary. +@c APPLE LOCAL end weak types 5954418 + +@c APPLE LOCAL begin 5946347 ms_struct support +@end table + +To specify multiple attributes, separate them by commas within the +double parentheses: for example, @samp{__attribute__ ((aligned (16), +packed))}. + +@anchor{i386 Type Attributes} +@subsection i386 Type Attributes + +Two attributes are currently defined for i386 configurations: +@code{ms_struct} and @code{gcc_struct} + +@table @code +@item ms_struct +@itemx gcc_struct +@cindex @code{ms_struct} attribute +@cindex @code{gcc_struct} attribute + +If @code{packed} is used on a structure, or if bit-fields are used +it may be that the Microsoft ABI packs them differently +than GCC would normally pack them. Particularly when moving packed +data between functions compiled with GCC and the native Microsoft compiler +(either via function call or as data in a file), it may be necessary to access +either format. + +Currently @option{-m[no-]ms-bitfields} is provided for the Microsoft Windows X86 +compilers to match the native Microsoft compiler. + +The Microsoft structure layout algorithm is fairly simple with the exception +of the bitfield packing: + +The padding and alignment of members of structures and whether a bit field +can straddle a storage-unit boundary + +@enumerate +@item Structure members are stored sequentially in the order in which they are +declared: the first member has the lowest memory address and the last member +the highest. + +@item Every data object has an alignment-requirement. The alignment-requirement +for all data except structures, unions, and arrays is either the size of the +object or the current packing size (specified with either the aligned attribute +or the pack pragma), whichever is less. For structures, unions, and arrays, +the alignment-requirement is the largest alignment-requirement of its members. +Every object is allocated an offset so that: + +offset % alignment-requirement == 0 + +@item Adjacent bit fields are packed into the same 1-, 2-, or 4-byte allocation +unit if the integral types are the same size and if the next bit field fits +into the current allocation unit without crossing the boundary imposed by the +common alignment requirements of the bit fields. +@end enumerate + +Handling of zero-length bitfields: + +MSVC interprets zero-length bitfields in the following ways: + +@enumerate +@item If a zero-length bitfield is inserted between two bitfields that would +normally be coalesced, the bitfields will not be coalesced. + +For example: + +@smallexample +struct + @{ + unsigned long bf_1 : 12; + unsigned long : 0; + unsigned long bf_2 : 12; + @} t1; +@end smallexample + +The size of @code{t1} would be 8 bytes with the zero-length bitfield. If the +zero-length bitfield were removed, @code{t1}'s size would be 4 bytes. + +@item If a zero-length bitfield is inserted after a bitfield, @code{foo}, and the +alignment of the zero-length bitfield is greater than the member that follows it, +@code{bar}, @code{bar} will be aligned as the type of the zero-length bitfield. + +For example: + +@smallexample +struct + @{ + char foo : 4; + short : 0; + char bar; + @} t2; + +struct + @{ + char foo : 4; + short : 0; + double bar; + @} t3; +@end smallexample + +For @code{t2}, @code{bar} will be placed at offset 2, rather than offset 1. +Accordingly, the size of @code{t2} will be 4. For @code{t3}, the zero-length +bitfield will not affect the alignment of @code{bar} or, as a result, the size +of the structure. + +Taking this into account, it is important to note the following: + +@enumerate +@item If a zero-length bitfield follows a normal bitfield, the type of the +zero-length bitfield may affect the alignment of the structure as whole. For +example, @code{t2} has a size of 4 bytes, since the zero-length bitfield follows a +normal bitfield, and is of type short. + +@item Even if a zero-length bitfield is not followed by a normal bitfield, it may +still affect the alignment of the structure: + +@smallexample +struct + @{ + char foo : 6; + long : 0; + @} t4; +@end smallexample + +Here, @code{t4} will take up 4 bytes. +@end enumerate + +@item Zero-length bitfields following non-bitfield members are ignored: + +@smallexample +struct + @{ + char foo; + long : 0; + char bar; + @} t5; +@end smallexample + +Here, @code{t5} will take up 2 bytes. +@end enumerate +@end table + +@anchor{ARM Type Attributes} +@subsection ARM Type Attributes + +Two attributes currently are defined for ARM configurations: +@code{ms_struct} and @code{gcc_struct}. + +For full documentation of the struct attributes please see the +documentation in the @xref{i386 Type Attributes}, section. + +On those ARM targets that support @code{dllimport} (such as Symbian +OS), you can use the @code{notshared} attribute to indicate that the +virtual table and other similar data for a class should not be +exported from a DLL@. For example: + +@smallexample +class __declspec(notshared) C @{ +public: + __declspec(dllimport) C(); + virtual void f(); +@} + +__declspec(dllexport) +C::C() @{@} +@end smallexample + +In this code, @code{C::C} is exported from the current DLL, but the +virtual table for @code{C} is not exported. (You can use +@code{__attribute__} instead of @code{__declspec} if you prefer, but +most Symbian OS code uses @code{__declspec}.) +@c APPLE LOCAL end 5946347 ms_struct support + +@anchor{PowerPC Type Attributes} +@subsection PowerPC Type Attributes + +Three attributes currently are defined for PowerPC configurations: +@code{altivec}, @code{ms_struct} and @code{gcc_struct}. + +For full documentation of the struct attributes please see the +documentation in the @xref{i386 Type Attributes}, section. + +The @code{altivec} attribute allows one to declare AltiVec vector data +types supported by the AltiVec Programming Interface Manual. The +attribute requires an argument to specify one of three vector types: +@code{vector__}, @code{pixel__} (always followed by unsigned short), +and @code{bool__} (always followed by unsigned). + +@smallexample +__attribute__((altivec(vector__))) +__attribute__((altivec(pixel__))) unsigned short +__attribute__((altivec(bool__))) unsigned +@end smallexample + +These attributes mainly are intended to support the @code{__vector}, +@code{__pixel}, and @code{__bool} AltiVec keywords. + +@c APPLE LOCAL begin for-fsf-4_4 3274130 5295549 +@node Label Attributes +@section Specifying Attributes of Labels and Statements +@cindex attribute of labels +@cindex label attributes +@cindex attribute of statements +@cindex statement attributes + +The keyword @code{__attribute__} allows you to specify special +attributes of labels and statements. + +Some attributes are currently defined generically for variables. +Other attributes are defined for variables on particular target +systems. Other attributes are available for functions +(@pxref{Function Attributes}), types (@pxref{Type Attributes}) and +variables (@pxref{Variable Attributes}). + +You may also specify attributes with @samp{__} preceding and following +each keyword. This allows you to use them in header files without +being concerned about a possible macro of the same name. For example, +you may use @code{__aligned__} instead of @code{aligned}. + +@xref{Attribute Syntax}, for details of the exact syntax for using +attributes. + +@table @code +@cindex @code{aligned} attribute +@item aligned (@var{alignment}) +This attribute specifies a minimum alignment for the label, +measured in bytes. For example, the declaration: + +@smallexample + some_label: __attribute__((aligned(16))) +@end smallexample + +@noindent +requests the compiler to align the label, inserting @code{nop}s as necessary, +to a 16-byte boundary. + +The alignment is only a request. The compiler will usually be able to +honour it but sometimes the label will be eliminated by the compiler, +in which case its alignment will be eliminated too. + +When applied to loops, the @code{aligned} attribute causes the loop to +be aligned. + +@item unused +When attached to a label this attribute means that the label might not +be used. GCC will not produce a warning for the label, even if the +label doesn't seem to be referenced. This feature is intended for +code generated by programs which contains labels that may be unused +but which is compiled with @option{-Wall}. It would not normally be +appropriate to use in it human-written code, though it could be useful +in cases where the code that jumps to the label is contained within an +@code{#ifdef} conditional. + +This attribute can only be applied to labels, not statements, because +there is no warning if a statement is removed. +@end table + +@c APPLE LOCAL end for-fsf-4_4 3274130 5295549 +@node Inline +@section An Inline Function is As Fast As a Macro +@cindex inline functions +@cindex integrating function code +@cindex open coding +@cindex macros, inline alternative + +@c APPLE LOCAL begin mainline 4.3 2006-10-31 4134307 +By declaring a function inline, you can direct GCC to make +calls to that function faster. One way GCC can achieve this is to +integrate that function's code into the code for its callers. This +makes execution faster by eliminating the function-call overhead; in +addition, if any of the actual argument values are constant, their +known values may permit simplifications at compile time so that not +all of the inline function's code needs to be included. The effect on +code size is less predictable; object code may be larger or smaller +with function inlining, depending on the particular case. You can +also direct GCC to try to integrate all ``simple enough'' functions +into their callers with the option @option{-finline-functions}. + +GCC implements three different semantics of declaring a function +inline. One is available with @option{-std=gnu89} or +@option{-fgnu89-inline} or when @code{gnu_inline} attribute is present +on all inline declarations, another when @option{-std=c99} or +@option{-std=gnu99} (without @option{-fgnu89-inline}), and the third +is used when compiling C++. + +@c APPLE LOCAL begin Ians 4.2 wording for extern inline +The preprocessor macros +@code{__GNUC_GNU_INLINE__} and @code{__GNUC_STDC_INLINE__} may be used +to determine the handling of @code{inline} during a particular +compilation (@pxref{Common Predefined Macros,,,cpp,The C +Preprocessor}). +@c APPLE LOCAL end Ians 4.2 wording for extern inline + +To declare a function inline, use the @code{inline} keyword in its +declaration, like this: + +@smallexample +static inline int +inc (int *a) +@{ + (*a)++; +@} +@end smallexample + +If you are writing a header file to be included in ISO C89 programs, write +@code{__inline__} instead of @code{inline}. @xref{Alternate Keywords}. + +The three types of inlining behave similarly in two important cases: +when the @code{inline} keyword is used on a @code{static} function, +like the example above, and when a function is first declared without +using the @code{inline} keyword and then is defined with +@code{inline}, like this: + +@smallexample +extern int inc (int *a); +inline int +inc (int *a) +@{ + (*a)++; +@} +@end smallexample + +In both of these common cases, the program behaves the same as if you +had not used the @code{inline} keyword, except for its speed. + +@cindex inline functions, omission of +@opindex fkeep-inline-functions +When a function is both inline and @code{static}, if all calls to the +function are integrated into the caller, and the function's address is +never used, then the function's own assembler code is never referenced. +In this case, GCC does not actually output assembler code for the +function, unless you specify the option @option{-fkeep-inline-functions}. +Some calls cannot be integrated for various reasons (in particular, +calls that precede the function's definition cannot be integrated, and +neither can recursive calls within the definition). If there is a +nonintegrated call, then the function is compiled to assembler code as +usual. The function must also be compiled as usual if the program +refers to its address, because that can't be inlined. + +@opindex Winline +Note that certain usages in a function definition can make it unsuitable +for inline substitution. Among these usages are: use of varargs, use of +alloca, use of variable sized data types (@pxref{Variable Length}), +use of computed goto (@pxref{Labels as Values}), use of nonlocal goto, +and nested functions (@pxref{Nested Functions}). Using @option{-Winline} +will warn when a function marked @code{inline} could not be substituted, +and will give the reason for the failure. + +@cindex automatic @code{inline} for C++ member fns +@cindex @code{inline} automatic for C++ member fns +@cindex member fns, automatically @code{inline} +@cindex C++ member fns, automatically @code{inline} +@opindex fno-default-inline +As required by ISO C++, GCC considers member functions defined within +the body of a class to be marked inline even if they are +not explicitly declared with the @code{inline} keyword. You can +override this with @option{-fno-default-inline}; @pxref{C++ Dialect +Options,,Options Controlling C++ Dialect}. + +GCC does not inline any functions when not optimizing unless you specify +the @samp{always_inline} attribute for the function, like this: + +@smallexample +/* @r{Prototype.} */ +inline void foo (const char) __attribute__((always_inline)); +@end smallexample + +The remainder of this section is specific to GNU C89 inlining. + +@cindex non-static inline function +When an inline function is not @code{static}, then the compiler must assume +that there may be calls from other source files; since a global symbol can +be defined only once in any program, the function must not be defined in +the other source files, so the calls therein cannot be integrated. +Therefore, a non-@code{static} inline function is always compiled on its +own in the usual fashion. + +If you specify both @code{inline} and @code{extern} in the function +definition, then the definition is used only for inlining. In no case +is the function compiled on its own, not even if you refer to its +address explicitly. Such an address becomes an external reference, as +if you had only declared the function, and had not defined it. + +This combination of @code{inline} and @code{extern} has almost the +effect of a macro. The way to use it is to put a function definition in +a header file with these keywords, and put another copy of the +definition (lacking @code{inline} and @code{extern}) in a library file. +The definition in the header file will cause most calls to the function +to be inlined. If any uses of the function remain, they will refer to +the single copy in the library. +@c APPLE LOCAL end mainline 4.3 2006-10-31 4134307 + +GCC does not inline any functions when not optimizing unless you specify +the @samp{always_inline} attribute for the function, like this: + +@smallexample +/* @r{Prototype.} */ +inline void foo (const char) __attribute__((always_inline)); +@end smallexample + +@node Extended Asm +@section Assembler Instructions with C Expression Operands +@cindex extended @code{asm} +@cindex @code{asm} expressions +@cindex assembler instructions +@cindex registers + +In an assembler instruction using @code{asm}, you can specify the +operands of the instruction using C expressions. This means you need not +guess which registers or memory locations will contain the data you want +to use. + +You must specify an assembler instruction template much like what +appears in a machine description, plus an operand constraint string for +each operand. + +For example, here is how to use the 68881's @code{fsinx} instruction: + +@smallexample +asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); +@end smallexample + +@noindent +Here @code{angle} is the C expression for the input operand while +@code{result} is that of the output operand. Each has @samp{"f"} as its +operand constraint, saying that a floating point register is required. +The @samp{=} in @samp{=f} indicates that the operand is an output; all +output operands' constraints must use @samp{=}. The constraints use the +same language used in the machine description (@pxref{Constraints}). + +Each operand is described by an operand-constraint string followed by +the C expression in parentheses. A colon separates the assembler +template from the first output operand and another separates the last +output operand from the first input, if any. Commas separate the +operands within each group. The total number of operands is currently +limited to 30; this limitation may be lifted in some future version of +GCC@. + +If there are no output operands but there are input operands, you must +place two consecutive colons surrounding the place where the output +operands would go. + +As of GCC version 3.1, it is also possible to specify input and output +operands using symbolic names which can be referenced within the +assembler code. These names are specified inside square brackets +preceding the constraint string, and can be referenced inside the +assembler code using @code{%[@var{name}]} instead of a percentage sign +followed by the operand number. Using named operands the above example +could look like: + +@smallexample +asm ("fsinx %[angle],%[output]" + : [output] "=f" (result) + : [angle] "f" (angle)); +@end smallexample + +@noindent +Note that the symbolic operand names have no relation whatsoever to +other C identifiers. You may use any name you like, even those of +existing C symbols, but you must ensure that no two operands within the same +assembler construct use the same symbolic name. + +Output operand expressions must be lvalues; the compiler can check this. +The input operands need not be lvalues. The compiler cannot check +whether the operands have data types that are reasonable for the +instruction being executed. It does not parse the assembler instruction +template and does not know what it means or even whether it is valid +assembler input. The extended @code{asm} feature is most often used for +machine instructions the compiler itself does not know exist. If +the output expression cannot be directly addressed (for example, it is a +bit-field), your constraint must allow a register. In that case, GCC +will use the register as the output of the @code{asm}, and then store +that register into the output. + +The ordinary output operands must be write-only; GCC will assume that +the values in these operands before the instruction are dead and need +not be generated. Extended asm supports input-output or read-write +operands. Use the constraint character @samp{+} to indicate such an +operand and list it with the output operands. You should only use +read-write operands when the constraints for the operand (or the +operand in which only some of the bits are to be changed) allow a +register. + +You may, as an alternative, logically split its function into two +separate operands, one input operand and one write-only output +operand. The connection between them is expressed by constraints +which say they need to be in the same location when the instruction +executes. You can use the same C expression for both operands, or +different expressions. For example, here we write the (fictitious) +@samp{combine} instruction with @code{bar} as its read-only source +operand and @code{foo} as its read-write destination: + +@smallexample +asm ("combine %2,%0" : "=r" (foo) : "0" (foo), "g" (bar)); +@end smallexample + +@noindent +The constraint @samp{"0"} for operand 1 says that it must occupy the +same location as operand 0. A number in constraint is allowed only in +an input operand and it must refer to an output operand. + +Only a number in the constraint can guarantee that one operand will be in +the same place as another. The mere fact that @code{foo} is the value +of both operands is not enough to guarantee that they will be in the +same place in the generated assembler code. The following would not +work reliably: + +@smallexample +asm ("combine %2,%0" : "=r" (foo) : "r" (foo), "g" (bar)); +@end smallexample + +Various optimizations or reloading could cause operands 0 and 1 to be in +different registers; GCC knows no reason not to do so. For example, the +compiler might find a copy of the value of @code{foo} in one register and +use it for operand 1, but generate the output operand 0 in a different +register (copying it afterward to @code{foo}'s own address). Of course, +since the register for operand 1 is not even mentioned in the assembler +code, the result will not work, but GCC can't tell that. + +As of GCC version 3.1, one may write @code{[@var{name}]} instead of +the operand number for a matching constraint. For example: + +@smallexample +asm ("cmoveq %1,%2,%[result]" + : [result] "=r"(result) + : "r" (test), "r"(new), "[result]"(old)); +@end smallexample + +Sometimes you need to make an @code{asm} operand be a specific register, +but there's no matching constraint letter for that register @emph{by +itself}. To force the operand into that register, use a local variable +for the operand and specify the register in the variable declaration. +@xref{Explicit Reg Vars}. Then for the @code{asm} operand, use any +register constraint letter that matches the register: + +@smallexample +register int *p1 asm ("r0") = @dots{}; +register int *p2 asm ("r1") = @dots{}; +register int *result asm ("r0"); +asm ("sysint" : "=r" (result) : "0" (p1), "r" (p2)); +@end smallexample + +@anchor{Example of asm with clobbered asm reg} +In the above example, beware that a register that is call-clobbered by +the target ABI will be overwritten by any function call in the +assignment, including library calls for arithmetic operators. +Assuming it is a call-clobbered register, this may happen to @code{r0} +above by the assignment to @code{p2}. If you have to use such a +register, use temporary variables for expressions between the register +assignment and use: + +@smallexample +int t1 = @dots{}; +register int *p1 asm ("r0") = @dots{}; +register int *p2 asm ("r1") = t1; +register int *result asm ("r0"); +asm ("sysint" : "=r" (result) : "0" (p1), "r" (p2)); +@end smallexample + +Some instructions clobber specific hard registers. To describe this, +write a third colon after the input operands, followed by the names of +the clobbered hard registers (given as strings). Here is a realistic +example for the VAX: + +@smallexample +asm volatile ("movc3 %0,%1,%2" + : /* @r{no outputs} */ + : "g" (from), "g" (to), "g" (count) + : "r0", "r1", "r2", "r3", "r4", "r5"); +@end smallexample + +You may not write a clobber description in a way that overlaps with an +input or output operand. For example, you may not have an operand +describing a register class with one member if you mention that register +in the clobber list. Variables declared to live in specific registers +(@pxref{Explicit Reg Vars}), and used as asm input or output operands must +have no part mentioned in the clobber description. +There is no way for you to specify that an input +operand is modified without also specifying it as an output +operand. Note that if all the output operands you specify are for this +purpose (and hence unused), you will then also need to specify +@code{volatile} for the @code{asm} construct, as described below, to +prevent GCC from deleting the @code{asm} statement as unused. + +If you refer to a particular hardware register from the assembler code, +you will probably have to list the register after the third colon to +tell the compiler the register's value is modified. In some assemblers, +the register names begin with @samp{%}; to produce one @samp{%} in the +assembler code, you must write @samp{%%} in the input. + +If your assembler instruction can alter the condition code register, add +@samp{cc} to the list of clobbered registers. GCC on some machines +represents the condition codes as a specific hardware register; +@samp{cc} serves to name this register. On other machines, the +condition code is handled differently, and specifying @samp{cc} has no +effect. But it is valid no matter what the machine. + +If your assembler instructions access memory in an unpredictable +fashion, add @samp{memory} to the list of clobbered registers. This +will cause GCC to not keep memory values cached in registers across the +assembler instruction and not optimize stores or loads to that memory. +You will also want to add the @code{volatile} keyword if the memory +affected is not listed in the inputs or outputs of the @code{asm}, as +the @samp{memory} clobber does not count as a side-effect of the +@code{asm}. If you know how large the accessed memory is, you can add +it as input or output but if this is not known, you should add +@samp{memory}. As an example, if you access ten bytes of a string, you +can use a memory input like: + +@smallexample +@{"m"( (@{ struct @{ char x[10]; @} *p = (void *)ptr ; *p; @}) )@}. +@end smallexample + +Note that in the following example the memory input is necessary, +otherwise GCC might optimize the store to @code{x} away: +@smallexample +int foo () +@{ + int x = 42; + int *y = &x; + int result; + asm ("magic stuff accessing an 'int' pointed to by '%1'" + "=&d" (r) : "a" (y), "m" (*y)); + return result; +@} +@end smallexample + +You can put multiple assembler instructions together in a single +@code{asm} template, separated by the characters normally used in assembly +code for the system. A combination that works in most places is a newline +to break the line, plus a tab character to move to the instruction field +(written as @samp{\n\t}). Sometimes semicolons can be used, if the +assembler allows semicolons as a line-breaking character. Note that some +assembler dialects use semicolons to start a comment. +The input operands are guaranteed not to use any of the clobbered +registers, and neither will the output operands' addresses, so you can +read and write the clobbered registers as many times as you like. Here +is an example of multiple instructions in a template; it assumes the +subroutine @code{_foo} accepts arguments in registers 9 and 10: + +@smallexample +asm ("movl %0,r9\n\tmovl %1,r10\n\tcall _foo" + : /* no outputs */ + : "g" (from), "g" (to) + : "r9", "r10"); +@end smallexample + +Unless an output operand has the @samp{&} constraint modifier, GCC +may allocate it in the same register as an unrelated input operand, on +the assumption the inputs are consumed before the outputs are produced. +This assumption may be false if the assembler code actually consists of +more than one instruction. In such a case, use @samp{&} for each output +operand that may not overlap an input. @xref{Modifiers}. + +If you want to test the condition code produced by an assembler +instruction, you must include a branch and a label in the @code{asm} +construct, as follows: + +@smallexample +asm ("clr %0\n\tfrob %1\n\tbeq 0f\n\tmov #1,%0\n0:" + : "g" (result) + : "g" (input)); +@end smallexample + +@noindent +This assumes your assembler supports local labels, as the GNU assembler +and most Unix assemblers do. + +Speaking of labels, jumps from one @code{asm} to another are not +supported. The compiler's optimizers do not know about these jumps, and +therefore they cannot take account of them when deciding how to +optimize. + +@cindex macros containing @code{asm} +Usually the most convenient way to use these @code{asm} instructions is to +encapsulate them in macros that look like functions. For example, + +@smallexample +#define sin(x) \ +(@{ double __value, __arg = (x); \ + asm ("fsinx %1,%0": "=f" (__value): "f" (__arg)); \ + __value; @}) +@end smallexample + +@noindent +Here the variable @code{__arg} is used to make sure that the instruction +operates on a proper @code{double} value, and to accept only those +arguments @code{x} which can convert automatically to a @code{double}. + +Another way to make sure the instruction operates on the correct data +type is to use a cast in the @code{asm}. This is different from using a +variable @code{__arg} in that it converts more different types. For +example, if the desired type were @code{int}, casting the argument to +@code{int} would accept a pointer with no complaint, while assigning the +argument to an @code{int} variable named @code{__arg} would warn about +using a pointer unless the caller explicitly casts it. + +If an @code{asm} has output operands, GCC assumes for optimization +purposes the instruction has no side effects except to change the output +operands. This does not mean instructions with a side effect cannot be +used, but you must be careful, because the compiler may eliminate them +if the output operands aren't used, or move them out of loops, or +replace two with one if they constitute a common subexpression. Also, +if your instruction does have a side effect on a variable that otherwise +appears not to change, the old value of the variable may be reused later +if it happens to be found in a register. + +You can prevent an @code{asm} instruction from being deleted +by writing the keyword @code{volatile} after +the @code{asm}. For example: + +@smallexample +#define get_and_set_priority(new) \ +(@{ int __old; \ + asm volatile ("get_and_set_priority %0, %1" \ + : "=g" (__old) : "g" (new)); \ + __old; @}) +@end smallexample + +@noindent +The @code{volatile} keyword indicates that the instruction has +important side-effects. GCC will not delete a volatile @code{asm} if +it is reachable. (The instruction can still be deleted if GCC can +prove that control-flow will never reach the location of the +instruction.) Note that even a volatile @code{asm} instruction +can be moved relative to other code, including across jump +instructions. For example, on many targets there is a system +register which can be set to control the rounding mode of +floating point operations. You might try +setting it with a volatile @code{asm}, like this PowerPC example: + +@smallexample + asm volatile("mtfsf 255,%0" : : "f" (fpenv)); + sum = x + y; +@end smallexample + +@noindent +This will not work reliably, as the compiler may move the addition back +before the volatile @code{asm}. To make it work you need to add an +artificial dependency to the @code{asm} referencing a variable in the code +you don't want moved, for example: + +@smallexample + asm volatile ("mtfsf 255,%1" : "=X"(sum): "f"(fpenv)); + sum = x + y; +@end smallexample + +Similarly, you can't expect a +sequence of volatile @code{asm} instructions to remain perfectly +consecutive. If you want consecutive output, use a single @code{asm}. +Also, GCC will perform some optimizations across a volatile @code{asm} +instruction; GCC does not ``forget everything'' when it encounters +a volatile @code{asm} instruction the way some other compilers do. + +An @code{asm} instruction without any output operands will be treated +identically to a volatile @code{asm} instruction. + +It is a natural idea to look for a way to give access to the condition +code left by the assembler instruction. However, when we attempted to +implement this, we found no way to make it work reliably. The problem +is that output operands might need reloading, which would result in +additional following ``store'' instructions. On most machines, these +instructions would alter the condition code before there was time to +test it. This problem doesn't arise for ordinary ``test'' and +``compare'' instructions because they don't have any output operands. + +For reasons similar to those described above, it is not possible to give +an assembler instruction access to the condition code left by previous +instructions. + +If you are writing a header file that should be includable in ISO C +programs, write @code{__asm__} instead of @code{asm}. @xref{Alternate +Keywords}. + +@subsection Size of an @code{asm} + +Some targets require that GCC track the size of each instruction used in +order to generate correct code. Because the final length of an +@code{asm} is only known by the assembler, GCC must make an estimate as +to how big it will be. The estimate is formed by counting the number of +statements in the pattern of the @code{asm} and multiplying that by the +length of the longest instruction on that processor. Statements in the +@code{asm} are identified by newline characters and whatever statement +separator characters are supported by the assembler; on most processors +this is the `@code{;}' character. + +Normally, GCC's estimate is perfectly adequate to ensure that correct +code is generated, but it is possible to confuse the compiler if you use +pseudo instructions or assembler macros that expand into multiple real +instructions or if you use assembler directives that expand to more +space in the object file than would be needed for a single instruction. +If this happens then the assembler will produce a diagnostic saying that +a label is unreachable. + +@subsection i386 floating point asm operands + +There are several rules on the usage of stack-like regs in +asm_operands insns. These rules apply only to the operands that are +stack-like regs: + +@enumerate +@item +Given a set of input regs that die in an asm_operands, it is +necessary to know which are implicitly popped by the asm, and +which must be explicitly popped by gcc. + +An input reg that is implicitly popped by the asm must be +explicitly clobbered, unless it is constrained to match an +output operand. + +@item +For any input reg that is implicitly popped by an asm, it is +necessary to know how to adjust the stack to compensate for the pop. +If any non-popped input is closer to the top of the reg-stack than +the implicitly popped reg, it would not be possible to know what the +stack looked like---it's not clear how the rest of the stack ``slides +up''. + +All implicitly popped input regs must be closer to the top of +the reg-stack than any input that is not implicitly popped. + +It is possible that if an input dies in an insn, reload might +use the input reg for an output reload. Consider this example: + +@smallexample +asm ("foo" : "=t" (a) : "f" (b)); +@end smallexample + +This asm says that input B is not popped by the asm, and that +the asm pushes a result onto the reg-stack, i.e., the stack is one +deeper after the asm than it was before. But, it is possible that +reload will think that it can use the same reg for both the input and +the output, if input B dies in this insn. + +If any input operand uses the @code{f} constraint, all output reg +constraints must use the @code{&} earlyclobber. + +The asm above would be written as + +@smallexample +asm ("foo" : "=&t" (a) : "f" (b)); +@end smallexample + +@item +Some operands need to be in particular places on the stack. All +output operands fall in this category---there is no other way to +know which regs the outputs appear in unless the user indicates +this in the constraints. + +Output operands must specifically indicate which reg an output +appears in after an asm. @code{=f} is not allowed: the operand +constraints must select a class with a single reg. + +@item +Output operands may not be ``inserted'' between existing stack regs. +Since no 387 opcode uses a read/write operand, all output operands +are dead before the asm_operands, and are pushed by the asm_operands. +It makes no sense to push anywhere but the top of the reg-stack. + +Output operands must start at the top of the reg-stack: output +operands may not ``skip'' a reg. + +@item +Some asm statements may need extra stack space for internal +calculations. This can be guaranteed by clobbering stack registers +unrelated to the inputs and outputs. + +@end enumerate + +Here are a couple of reasonable asms to want to write. This asm +takes one input, which is internally popped, and produces two outputs. + +@smallexample +asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp)); +@end smallexample + +This asm takes two inputs, which are popped by the @code{fyl2xp1} opcode, +and replaces them with one output. The user must code the @code{st(1)} +clobber for reg-stack.c to know that @code{fyl2xp1} pops both inputs. + +@smallexample +asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)"); +@end smallexample + +@include md.texi + +@node Asm Labels +@section Controlling Names Used in Assembler Code +@cindex assembler names for identifiers +@cindex names used in assembler code +@cindex identifiers, names in assembler code + +You can specify the name to be used in the assembler code for a C +function or variable by writing the @code{asm} (or @code{__asm__}) +keyword after the declarator as follows: + +@smallexample +int foo asm ("myfoo") = 2; +@end smallexample + +@noindent +This specifies that the name to be used for the variable @code{foo} in +the assembler code should be @samp{myfoo} rather than the usual +@samp{_foo}. + +On systems where an underscore is normally prepended to the name of a C +function or variable, this feature allows you to define names for the +linker that do not start with an underscore. + +It does not make sense to use this feature with a non-static local +variable since such variables do not have assembler names. If you are +trying to put the variable in a particular register, see @ref{Explicit +Reg Vars}. GCC presently accepts such code with a warning, but will +probably be changed to issue an error, rather than a warning, in the +future. + +You cannot use @code{asm} in this way in a function @emph{definition}; but +you can get the same effect by writing a declaration for the function +before its definition and putting @code{asm} there, like this: + +@smallexample +extern func () asm ("FUNC"); + +func (x, y) + int x, y; +/* @r{@dots{}} */ +@end smallexample + +It is up to you to make sure that the assembler names you choose do not +conflict with any other assembler symbols. Also, you must not use a +register name; that would produce completely invalid assembler code. GCC +does not as yet have the ability to store static variables in registers. +Perhaps that will be added. + +@node Explicit Reg Vars +@section Variables in Specified Registers +@cindex explicit register variables +@cindex variables in specified registers +@cindex specified registers +@cindex registers, global allocation + +GNU C allows you to put a few global variables into specified hardware +registers. You can also specify the register in which an ordinary +register variable should be allocated. + +@itemize @bullet +@item +Global register variables reserve registers throughout the program. +This may be useful in programs such as programming language +interpreters which have a couple of global variables that are accessed +very often. + +@item +Local register variables in specific registers do not reserve the +registers, except at the point where they are used as input or output +operands in an @code{asm} statement and the @code{asm} statement itself is +not deleted. The compiler's data flow analysis is capable of determining +where the specified registers contain live values, and where they are +available for other uses. Stores into local register variables may be deleted +when they appear to be dead according to dataflow analysis. References +to local register variables may be deleted or moved or simplified. + +These local variables are sometimes convenient for use with the extended +@code{asm} feature (@pxref{Extended Asm}), if you want to write one +output of the assembler instruction directly into a particular register. +(This will work provided the register you specify fits the constraints +specified for that operand in the @code{asm}.) +@end itemize + +@menu +* Global Reg Vars:: +* Local Reg Vars:: +@end menu + +@node Global Reg Vars +@subsection Defining Global Register Variables +@cindex global register variables +@cindex registers, global variables in + +You can define a global register variable in GNU C like this: + +@smallexample +register int *foo asm ("a5"); +@end smallexample + +@noindent +Here @code{a5} is the name of the register which should be used. Choose a +register which is normally saved and restored by function calls on your +machine, so that library routines will not clobber it. + +Naturally the register name is cpu-dependent, so you would need to +conditionalize your program according to cpu type. The register +@code{a5} would be a good choice on a 68000 for a variable of pointer +type. On machines with register windows, be sure to choose a ``global'' +register that is not affected magically by the function call mechanism. + +In addition, operating systems on one type of cpu may differ in how they +name the registers; then you would need additional conditionals. For +example, some 68000 operating systems call this register @code{%a5}. + +Eventually there may be a way of asking the compiler to choose a register +automatically, but first we need to figure out how it should choose and +how to enable you to guide the choice. No solution is evident. + +Defining a global register variable in a certain register reserves that +register entirely for this use, at least within the current compilation. +The register will not be allocated for any other purpose in the functions +in the current compilation. The register will not be saved and restored by +these functions. Stores into this register are never deleted even if they +would appear to be dead, but references may be deleted or moved or +simplified. + +It is not safe to access the global register variables from signal +handlers, or from more than one thread of control, because the system +library routines may temporarily use the register for other things (unless +you recompile them specially for the task at hand). + +@cindex @code{qsort}, and global register variables +It is not safe for one function that uses a global register variable to +call another such function @code{foo} by way of a third function +@code{lose} that was compiled without knowledge of this variable (i.e.@: in a +different source file in which the variable wasn't declared). This is +because @code{lose} might save the register and put some other value there. +For example, you can't expect a global register variable to be available in +the comparison-function that you pass to @code{qsort}, since @code{qsort} +might have put something else in that register. (If you are prepared to +recompile @code{qsort} with the same global register variable, you can +solve this problem.) + +If you want to recompile @code{qsort} or other source files which do not +actually use your global register variable, so that they will not use that +register for any other purpose, then it suffices to specify the compiler +option @option{-ffixed-@var{reg}}. You need not actually add a global +register declaration to their source code. + +A function which can alter the value of a global register variable cannot +safely be called from a function compiled without this variable, because it +could clobber the value the caller expects to find there on return. +Therefore, the function which is the entry point into the part of the +program that uses the global register variable must explicitly save and +restore the value which belongs to its caller. + +@cindex register variable after @code{longjmp} +@cindex global register after @code{longjmp} +@cindex value after @code{longjmp} +@findex longjmp +@findex setjmp +On most machines, @code{longjmp} will restore to each global register +variable the value it had at the time of the @code{setjmp}. On some +machines, however, @code{longjmp} will not change the value of global +register variables. To be portable, the function that called @code{setjmp} +should make other arrangements to save the values of the global register +variables, and to restore them in a @code{longjmp}. This way, the same +thing will happen regardless of what @code{longjmp} does. + +All global register variable declarations must precede all function +definitions. If such a declaration could appear after function +definitions, the declaration would be too late to prevent the register from +being used for other purposes in the preceding functions. + +Global register variables may not have initial values, because an +executable file has no means to supply initial contents for a register. + +On the SPARC, there are reports that g3 @dots{} g7 are suitable +registers, but certain library functions, such as @code{getwd}, as well +as the subroutines for division and remainder, modify g3 and g4. g1 and +g2 are local temporaries. + +On the 68000, a2 @dots{} a5 should be suitable, as should d2 @dots{} d7. +Of course, it will not do to use more than a few of those. + +@node Local Reg Vars +@subsection Specifying Registers for Local Variables +@cindex local variables, specifying registers +@cindex specifying registers for local variables +@cindex registers for local variables + +You can define a local register variable with a specified register +like this: + +@smallexample +register int *foo asm ("a5"); +@end smallexample + +@noindent +Here @code{a5} is the name of the register which should be used. Note +that this is the same syntax used for defining global register +variables, but for a local variable it would appear within a function. + +Naturally the register name is cpu-dependent, but this is not a +problem, since specific registers are most often useful with explicit +assembler instructions (@pxref{Extended Asm}). Both of these things +generally require that you conditionalize your program according to +cpu type. + +In addition, operating systems on one type of cpu may differ in how they +name the registers; then you would need additional conditionals. For +example, some 68000 operating systems call this register @code{%a5}. + +Defining such a register variable does not reserve the register; it +remains available for other uses in places where flow control determines +the variable's value is not live. + +This option does not guarantee that GCC will generate code that has +this variable in the register you specify at all times. You may not +code an explicit reference to this register in the @emph{assembler +instruction template} part of an @code{asm} statement and assume it will +always refer to this variable. However, using the variable as an +@code{asm} @emph{operand} guarantees that the specified register is used +for the operand. + +Stores into local register variables may be deleted when they appear to be dead +according to dataflow analysis. References to local register variables may +be deleted or moved or simplified. + +As for global register variables, it's recommended that you choose a +register which is normally saved and restored by function calls on +your machine, so that library routines will not clobber it. A common +pitfall is to initialize multiple call-clobbered registers with +arbitrary expressions, where a function call or library call for an +arithmetic operator will overwrite a register value from a previous +assignment, for example @code{r0} below: +@smallexample +register int *p1 asm ("r0") = @dots{}; +register int *p2 asm ("r1") = @dots{}; +@end smallexample +In those cases, a solution is to use a temporary variable for +each arbitrary expression. @xref{Example of asm with clobbered asm reg}. + +@c APPLE LOCAL begin CW asm blocks +@node Asm Blocks and Functions +@section Blocks and Functions of Assembly Language + +(This feature is APPLE ONLY.) + +In addition to writing single statements in assembly, you can also +define blocks and entire functions to use a mixed assembly and C +syntax. The syntax follows that used in Metrowerks' CodeWarrior on +PowerPC and Microsoft Visual Studio on x86. This extension must be +explicitly enabled with the @option{-fasm-blocks} option. + +The block syntax consists of @code{asm} followed by braces, with the +assembly instructions on separate lines. (However, @code{';'} may be +used to put several instructions on one line in CW-style, and +@code{asm} in either style.) You write labels with either a preceding +@code{'@@'} or a trailing @code{':'} (or both, if you prefer); labels +are always local to the asm blocks of the function. Comments and +lexical rules are as for standard C/C++. + +@verbatim +int foo (int arg) { + register int bar; + asm { + li bar, 42 + add bar, arg, bar ; nop ; ; nop + } + return bar; +} +@end verbatim + +The function syntax uses @code{asm} as a keyword in the function +definition. In this form, C declarations may appear at the beginning +of the function body, in order to declare variables that you want to +use in the body, but may not be used after the first assembly opcode +or label (even in C99 or C++). + +@verbatim +asm int baz (int arg1) { + register int loc1, loc2; + @123 + li loc1,4 * 89 + nand. r5,arg1,loc1 + ble- cr0, @123 + otherlab: nop + mr r3,r5 +} +@end verbatim + +Note that the compiler just passes the instructions through to the +assembler with only necessary changes, such as a substitution of +globally unique labels. Assembly syntax errors will therefore be +reported by the assembler. + +Also note that the use of literal registers (such as r3) in functions +may not work properly with functions that are being inlined. + +The following PowerPC instructions are assumed to affect memory: @code{l...} +except @code{la}, @code{li} and @code{lis} (all memory loads), +@code{st...} (all memory stores), @code{sc}, @code{td...}, +@code{trap}, @code{tw...}. All other instructions are assumed to not +affect memory. + +The following PowerPC instructions take a memory operand (address operand) as +their second operand, all other instructions are assumed to not: + +@code{la}, @code{lbzu}, @code{ld}, @code{ldu}, @code{lfd}, +@code{lfdu}, @code{lfs}, @code{lfsu}, @code{lha}, @code{lhau}, +@code{lhz}, @code{lhzu}, @code{lmw}, @code{lwa}, @code{lwz}, +@code{lwzu}, @code{stb}, @code{stbu}, @code{std}, @code{stdu}, +@code{stfd}, @code{stfdu}, @code{stfs}, @code{stfsu}, @code{sth}, +@code{sthu}, @code{stmw}, @code{stw}, @code{stwu}. + +Arguments that require substitution beyond vector registers, floating +point registers, general registers are not supported; an example +would be trying to use the compiler to allocate condition code +registers instead of just writting a specific condition code register. + +On x86, the following instructions are not yet implemented by the assembler: + +@code{bound r m}, +@code{cmovpe r rm}, +@code{cmovpo r rm}, +@code{cmovz r rm}, +@code{ins m d}, +@code{lods m}, +@code{movs m m} +@code{scas m}, +@code{stos m}, and +@code{xlat m}. + +Note, the letters after the instructions are the usual x86 contraint +letters for the operands. +@c APPLE LOCAL end CW asm blocks + +@node Alternate Keywords +@section Alternate Keywords +@cindex alternate keywords +@cindex keywords, alternate + +@option{-ansi} and the various @option{-std} options disable certain +keywords. This causes trouble when you want to use GNU C extensions, or +a general-purpose header file that should be usable by all programs, +including ISO C programs. The keywords @code{asm}, @code{typeof} and +@code{inline} are not available in programs compiled with +@option{-ansi} or @option{-std} (although @code{inline} can be used in a +program compiled with @option{-std=c99}). The ISO C99 keyword +@code{restrict} is only available when @option{-std=gnu99} (which will +eventually be the default) or @option{-std=c99} (or the equivalent +@option{-std=iso9899:1999}) is used. + +The way to solve these problems is to put @samp{__} at the beginning and +end of each problematical keyword. For example, use @code{__asm__} +instead of @code{asm}, and @code{__inline__} instead of @code{inline}. + +Other C compilers won't accept these alternative keywords; if you want to +compile with another compiler, you can define the alternate keywords as +macros to replace them with the customary keywords. It looks like this: + +@smallexample +#ifndef __GNUC__ +#define __asm__ asm +#endif +@end smallexample + +@findex __extension__ +@opindex pedantic +@option{-pedantic} and other options cause warnings for many GNU C extensions. +You can +prevent such warnings within one expression by writing +@code{__extension__} before the expression. @code{__extension__} has no +effect aside from this. + +@node Incomplete Enums +@section Incomplete @code{enum} Types + +You can define an @code{enum} tag without specifying its possible values. +This results in an incomplete type, much like what you get if you write +@code{struct foo} without describing the elements. A later declaration +which does specify the possible values completes the type. + +You can't allocate variables or storage using the type while it is +incomplete. However, you can work with pointers to that type. + +This extension may not be very useful, but it makes the handling of +@code{enum} more consistent with the way @code{struct} and @code{union} +are handled. + +This extension is not supported by GNU C++. + +@node Function Names +@section Function Names as Strings +@cindex @code{__func__} identifier +@cindex @code{__FUNCTION__} identifier +@cindex @code{__PRETTY_FUNCTION__} identifier + +GCC provides three magic variables which hold the name of the current +function, as a string. The first of these is @code{__func__}, which +is part of the C99 standard: + +@display +The identifier @code{__func__} is implicitly declared by the translator +as if, immediately following the opening brace of each function +definition, the declaration + +@smallexample +static const char __func__[] = "function-name"; +@end smallexample + +appeared, where function-name is the name of the lexically-enclosing +function. This name is the unadorned name of the function. +@end display + +@code{__FUNCTION__} is another name for @code{__func__}. Older +versions of GCC recognize only this name. However, it is not +standardized. For maximum portability, we recommend you use +@code{__func__}, but provide a fallback definition with the +preprocessor: + +@smallexample +#if __STDC_VERSION__ < 199901L +# if __GNUC__ >= 2 +# define __func__ __FUNCTION__ +# else +# define __func__ "<unknown>" +# endif +#endif +@end smallexample + +In C, @code{__PRETTY_FUNCTION__} is yet another name for +@code{__func__}. However, in C++, @code{__PRETTY_FUNCTION__} contains +the type signature of the function as well as its bare name. For +example, this program: + +@smallexample +extern "C" @{ +extern int printf (char *, ...); +@} + +class a @{ + public: + void sub (int i) + @{ + printf ("__FUNCTION__ = %s\n", __FUNCTION__); + printf ("__PRETTY_FUNCTION__ = %s\n", __PRETTY_FUNCTION__); + @} +@}; + +int +main (void) +@{ + a ax; + ax.sub (0); + return 0; +@} +@end smallexample + +@noindent +gives this output: + +@smallexample +__FUNCTION__ = sub +__PRETTY_FUNCTION__ = void a::sub(int) +@end smallexample + +These identifiers are not preprocessor macros. In GCC 3.3 and +earlier, in C only, @code{__FUNCTION__} and @code{__PRETTY_FUNCTION__} +were treated as string literals; they could be used to initialize +@code{char} arrays, and they could be concatenated with other string +literals. GCC 3.4 and later treat them as variables, like +@code{__func__}. In C++, @code{__FUNCTION__} and +@code{__PRETTY_FUNCTION__} have always been variables. + +@node Return Address +@section Getting the Return or Frame Address of a Function + +These functions may be used to get information about the callers of a +function. + +@deftypefn {Built-in Function} {void *} __builtin_return_address (unsigned int @var{level}) +This function returns the return address of the current function, or of +one of its callers. The @var{level} argument is number of frames to +scan up the call stack. A value of @code{0} yields the return address +of the current function, a value of @code{1} yields the return address +of the caller of the current function, and so forth. When inlining +the expected behavior is that the function will return the address of +the function that will be returned to. To work around this behavior use +the @code{noinline} function attribute. + +The @var{level} argument must be a constant integer. + +On some machines it may be impossible to determine the return address of +any function other than the current one; in such cases, or when the top +of the stack has been reached, this function will return @code{0} or a +random value. In addition, @code{__builtin_frame_address} may be used +to determine if the top of the stack has been reached. + +This function should only be used with a nonzero argument for debugging +purposes. +@end deftypefn + +@deftypefn {Built-in Function} {void *} __builtin_frame_address (unsigned int @var{level}) +This function is similar to @code{__builtin_return_address}, but it +returns the address of the function frame rather than the return address +of the function. Calling @code{__builtin_frame_address} with a value of +@code{0} yields the frame address of the current function, a value of +@code{1} yields the frame address of the caller of the current function, +and so forth. + +The frame is the area on the stack which holds local variables and saved +registers. The frame address is normally the address of the first word +pushed on to the stack by the function. However, the exact definition +depends upon the processor and the calling convention. If the processor +has a dedicated frame pointer register, and the function has a frame, +then @code{__builtin_frame_address} will return the value of the frame +pointer register. + +On some machines it may be impossible to determine the frame address of +any function other than the current one; in such cases, or when the top +of the stack has been reached, this function will return @code{0} if +the first frame pointer is properly initialized by the startup code. + +This function should only be used with a nonzero argument for debugging +purposes. +@end deftypefn + +@node Vector Extensions +@section Using vector instructions through built-in functions + +On some targets, the instruction set contains SIMD vector instructions that +operate on multiple values contained in one large register at the same time. +For example, on the i386 the MMX, 3Dnow! and SSE extensions can be used +this way. + +The first step in using these extensions is to provide the necessary data +types. This should be done using an appropriate @code{typedef}: + +@smallexample +typedef int v4si __attribute__ ((vector_size (16))); +@end smallexample + +The @code{int} type specifies the base type, while the attribute specifies +the vector size for the variable, measured in bytes. For example, the +declaration above causes the compiler to set the mode for the @code{v4si} +type to be 16 bytes wide and divided into @code{int} sized units. For +a 32-bit @code{int} this means a vector of 4 units of 4 bytes, and the +corresponding mode of @code{foo} will be @acronym{V4SI}. + +The @code{vector_size} attribute is only applicable to integral and +float scalars, although arrays, pointers, and function return values +are allowed in conjunction with this construct. + +All the basic integer types can be used as base types, both as signed +and as unsigned: @code{char}, @code{short}, @code{int}, @code{long}, +@code{long long}. In addition, @code{float} and @code{double} can be +used to build floating-point vector types. + +Specifying a combination that is not valid for the current architecture +will cause GCC to synthesize the instructions using a narrower mode. +For example, if you specify a variable of type @code{V4SI} and your +architecture does not allow for this specific SIMD type, GCC will +produce code that uses 4 @code{SIs}. + +The types defined in this manner can be used with a subset of normal C +operations. Currently, GCC will allow using the following operators +on these types: @code{+, -, *, /, unary minus, ^, |, &, ~}@. + +The operations behave like C++ @code{valarrays}. Addition is defined as +the addition of the corresponding elements of the operands. For +example, in the code below, each of the 4 elements in @var{a} will be +added to the corresponding 4 elements in @var{b} and the resulting +vector will be stored in @var{c}. + +@smallexample +typedef int v4si __attribute__ ((vector_size (16))); + +v4si a, b, c; + +c = a + b; +@end smallexample + +Subtraction, multiplication, division, and the logical operations +operate in a similar manner. Likewise, the result of using the unary +minus or complement operators on a vector type is a vector whose +elements are the negative or complemented values of the corresponding +elements in the operand. + +You can declare variables and use them in function calls and returns, as +well as in assignments and some casts. You can specify a vector type as +a return type for a function. Vector types can also be used as function +arguments. It is possible to cast from one vector type to another, +provided they are of the same size (in fact, you can also cast vectors +to and from other datatypes of the same size). + +You cannot operate between vectors of different lengths or different +signedness without a cast. + +A port that supports hardware vector operations, usually provides a set +of built-in functions that can be used to operate on vectors. For +example, a function to add two vectors and multiply the result by a +third could look like this: + +@smallexample +v4si f (v4si a, v4si b, v4si c) +@{ + v4si tmp = __builtin_addv4si (a, b); + return __builtin_mulv4si (tmp, c); +@} + +@end smallexample + +@node Offsetof +@section Offsetof +@findex __builtin_offsetof + +GCC implements for both C and C++ a syntactic extension to implement +the @code{offsetof} macro. + +@smallexample +primary: + "__builtin_offsetof" "(" @code{typename} "," offsetof_member_designator ")" + +offsetof_member_designator: + @code{identifier} + | offsetof_member_designator "." @code{identifier} + | offsetof_member_designator "[" @code{expr} "]" +@end smallexample + +This extension is sufficient such that + +@smallexample +#define offsetof(@var{type}, @var{member}) __builtin_offsetof (@var{type}, @var{member}) +@end smallexample + +is a suitable definition of the @code{offsetof} macro. In C++, @var{type} +may be dependent. In either case, @var{member} may consist of a single +identifier, or a sequence of member accesses and array references. + +@node Atomic Builtins +@section Built-in functions for atomic memory access + +The following builtins are intended to be compatible with those described +in the @cite{Intel Itanium Processor-specific Application Binary Interface}, +section 7.4. As such, they depart from the normal GCC practice of using +the ``__builtin_'' prefix, and further that they are overloaded such that +they work on multiple types. + +The definition given in the Intel documentation allows only for the use of +the types @code{int}, @code{long}, @code{long long} as well as their unsigned +counterparts. GCC will allow any integral scalar or pointer type that is +1, 2, 4 or 8 bytes in length. + +Not all operations are supported by all target processors. If a particular +operation cannot be implemented on the target processor, a warning will be +generated and a call an external function will be generated. The external +function will carry the same name as the builtin, with an additional suffix +@samp{_@var{n}} where @var{n} is the size of the data type. + +@c ??? Should we have a mechanism to suppress this warning? This is almost +@c useful for implementing the operation under the control of an external +@c mutex. + +In most cases, these builtins are considered a @dfn{full barrier}. That is, +no memory operand will be moved across the operation, either forward or +backward. Further, instructions will be issued as necessary to prevent the +processor from speculating loads across the operation and from queuing stores +after the operation. + +All of the routines are are described in the Intel documentation to take +``an optional list of variables protected by the memory barrier''. It's +not clear what is meant by that; it could mean that @emph{only} the +following variables are protected, or it could mean that these variables +should in addition be protected. At present GCC ignores this list and +protects all variables which are globally accessible. If in the future +we make some use of this list, an empty list will continue to mean all +globally accessible variables. + +@table @code +@item @var{type} __sync_fetch_and_add (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_fetch_and_sub (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_fetch_and_or (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_fetch_and_and (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_fetch_and_xor (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_fetch_and_nand (@var{type} *ptr, @var{type} value, ...) +@findex __sync_fetch_and_add +@findex __sync_fetch_and_sub +@findex __sync_fetch_and_or +@findex __sync_fetch_and_and +@findex __sync_fetch_and_xor +@findex __sync_fetch_and_nand +These builtins perform the operation suggested by the name, and +returns the value that had previously been in memory. That is, + +@smallexample +@{ tmp = *ptr; *ptr @var{op}= value; return tmp; @} +@{ tmp = *ptr; *ptr = ~tmp & value; return tmp; @} // nand +@end smallexample + +@item @var{type} __sync_add_and_fetch (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_sub_and_fetch (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_or_and_fetch (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_and_and_fetch (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_xor_and_fetch (@var{type} *ptr, @var{type} value, ...) +@itemx @var{type} __sync_nand_and_fetch (@var{type} *ptr, @var{type} value, ...) +@findex __sync_add_and_fetch +@findex __sync_sub_and_fetch +@findex __sync_or_and_fetch +@findex __sync_and_and_fetch +@findex __sync_xor_and_fetch +@findex __sync_nand_and_fetch +These builtins perform the operation suggested by the name, and +return the new value. That is, + +@smallexample +@{ *ptr @var{op}= value; return *ptr; @} +@{ *ptr = ~*ptr & value; return *ptr; @} // nand +@end smallexample + +@item bool __sync_bool_compare_and_swap (@var{type} *ptr, @var{type} oldval @var{type} newval, ...) +@itemx @var{type} __sync_val_compare_and_swap (@var{type} *ptr, @var{type} oldval @var{type} newval, ...) +@findex __sync_bool_compare_and_swap +@findex __sync_val_compare_and_swap +These builtins perform an atomic compare and swap. That is, if the current +value of @code{*@var{ptr}} is @var{oldval}, then write @var{newval} into +@code{*@var{ptr}}. + +The ``bool'' version returns true if the comparison is successful and +@var{newval} was written. The ``val'' version returns the contents +of @code{*@var{ptr}} before the operation. + +@item __sync_synchronize (...) +@findex __sync_synchronize +This builtin issues a full memory barrier. + +@item @var{type} __sync_lock_test_and_set (@var{type} *ptr, @var{type} value, ...) +@findex __sync_lock_test_and_set +This builtin, as described by Intel, is not a traditional test-and-set +operation, but rather an atomic exchange operation. It writes @var{value} +into @code{*@var{ptr}}, and returns the previous contents of +@code{*@var{ptr}}. + +Many targets have only minimal support for such locks, and do not support +a full exchange operation. In this case, a target may support reduced +functionality here by which the @emph{only} valid value to store is the +immediate constant 1. The exact value actually stored in @code{*@var{ptr}} +is implementation defined. + +This builtin is not a full barrier, but rather an @dfn{acquire barrier}. +This means that references after the builtin cannot move to (or be +speculated to) before the builtin, but previous memory stores may not +be globally visible yet, and previous memory loads may not yet be +satisfied. + +@item void __sync_lock_release (@var{type} *ptr, ...) +@findex __sync_lock_release +This builtin releases the lock acquired by @code{__sync_lock_test_and_set}. +Normally this means writing the constant 0 to @code{*@var{ptr}}. + +This builtin is not a full barrier, but rather a @dfn{release barrier}. +This means that all previous memory stores are globally visible, and all +previous memory loads have been satisfied, but following memory reads +are not prevented from being speculated to before the barrier. +@end table + +@node Object Size Checking +@section Object Size Checking Builtins +@findex __builtin_object_size +@findex __builtin___memcpy_chk +@findex __builtin___mempcpy_chk +@findex __builtin___memmove_chk +@findex __builtin___memset_chk +@findex __builtin___strcpy_chk +@findex __builtin___stpcpy_chk +@findex __builtin___strncpy_chk +@findex __builtin___strcat_chk +@findex __builtin___strncat_chk +@findex __builtin___sprintf_chk +@findex __builtin___snprintf_chk +@findex __builtin___vsprintf_chk +@findex __builtin___vsnprintf_chk +@findex __builtin___printf_chk +@findex __builtin___vprintf_chk +@findex __builtin___fprintf_chk +@findex __builtin___vfprintf_chk + +GCC implements a limited buffer overflow protection mechanism +that can prevent some buffer overflow attacks. + +@deftypefn {Built-in Function} {size_t} __builtin_object_size (void * @var{ptr}, int @var{type}) +is a built-in construct that returns a constant number of bytes from +@var{ptr} to the end of the object @var{ptr} pointer points to +(if known at compile time). @code{__builtin_object_size} never evaluates +its arguments for side-effects. If there are any side-effects in them, it +returns @code{(size_t) -1} for @var{type} 0 or 1 and @code{(size_t) 0} +for @var{type} 2 or 3. If there are multiple objects @var{ptr} can +point to and all of them are known at compile time, the returned number +is the maximum of remaining byte counts in those objects if @var{type} & 2 is +0 and minimum if nonzero. If it is not possible to determine which objects +@var{ptr} points to at compile time, @code{__builtin_object_size} should +return @code{(size_t) -1} for @var{type} 0 or 1 and @code{(size_t) 0} +for @var{type} 2 or 3. + +@var{type} is an integer constant from 0 to 3. If the least significant +bit is clear, objects are whole variables, if it is set, a closest +surrounding subobject is considered the object a pointer points to. +The second bit determines if maximum or minimum of remaining bytes +is computed. + +@smallexample +struct V @{ char buf1[10]; int b; char buf2[10]; @} var; +char *p = &var.buf1[1], *q = &var.b; + +/* Here the object p points to is var. */ +assert (__builtin_object_size (p, 0) == sizeof (var) - 1); +/* The subobject p points to is var.buf1. */ +assert (__builtin_object_size (p, 1) == sizeof (var.buf1) - 1); +/* The object q points to is var. */ +assert (__builtin_object_size (q, 0) + == (char *) (&var + 1) - (char *) &var.b); +/* The subobject q points to is var.b. */ +assert (__builtin_object_size (q, 1) == sizeof (var.b)); +@end smallexample +@end deftypefn + +There are built-in functions added for many common string operation +functions, e.g. for @code{memcpy} @code{__builtin___memcpy_chk} +built-in is provided. This built-in has an additional last argument, +which is the number of bytes remaining in object the @var{dest} +argument points to or @code{(size_t) -1} if the size is not known. + +The built-in functions are optimized into the normal string functions +like @code{memcpy} if the last argument is @code{(size_t) -1} or if +it is known at compile time that the destination object will not +be overflown. If the compiler can determine at compile time the +object will be always overflown, it issues a warning. + +The intended use can be e.g. + +@smallexample +#undef memcpy +#define bos0(dest) __builtin_object_size (dest, 0) +#define memcpy(dest, src, n) \ + __builtin___memcpy_chk (dest, src, n, bos0 (dest)) + +char *volatile p; +char buf[10]; +/* It is unknown what object p points to, so this is optimized + into plain memcpy - no checking is possible. */ +memcpy (p, "abcde", n); +/* Destination is known and length too. It is known at compile + time there will be no overflow. */ +memcpy (&buf[5], "abcde", 5); +/* Destination is known, but the length is not known at compile time. + This will result in __memcpy_chk call that can check for overflow + at runtime. */ +memcpy (&buf[5], "abcde", n); +/* Destination is known and it is known at compile time there will + be overflow. There will be a warning and __memcpy_chk call that + will abort the program at runtime. */ +memcpy (&buf[6], "abcde", 5); +@end smallexample + +Such built-in functions are provided for @code{memcpy}, @code{mempcpy}, +@code{memmove}, @code{memset}, @code{strcpy}, @code{stpcpy}, @code{strncpy}, +@code{strcat} and @code{strncat}. + +There are also checking built-in functions for formatted output functions. +@smallexample +int __builtin___sprintf_chk (char *s, int flag, size_t os, const char *fmt, ...); +int __builtin___snprintf_chk (char *s, size_t maxlen, int flag, size_t os, + const char *fmt, ...); +int __builtin___vsprintf_chk (char *s, int flag, size_t os, const char *fmt, + va_list ap); +int __builtin___vsnprintf_chk (char *s, size_t maxlen, int flag, size_t os, + const char *fmt, va_list ap); +@end smallexample + +The added @var{flag} argument is passed unchanged to @code{__sprintf_chk} +etc. functions and can contain implementation specific flags on what +additional security measures the checking function might take, such as +handling @code{%n} differently. + +The @var{os} argument is the object size @var{s} points to, like in the +other built-in functions. There is a small difference in the behavior +though, if @var{os} is @code{(size_t) -1}, the built-in functions are +optimized into the non-checking functions only if @var{flag} is 0, otherwise +the checking function is called with @var{os} argument set to +@code{(size_t) -1}. + +In addition to this, there are checking built-in functions +@code{__builtin___printf_chk}, @code{__builtin___vprintf_chk}, +@code{__builtin___fprintf_chk} and @code{__builtin___vfprintf_chk}. +These have just one additional argument, @var{flag}, right before +format string @var{fmt}. If the compiler is able to optimize them to +@code{fputc} etc. functions, it will, otherwise the checking function +should be called and the @var{flag} argument passed to it. + +@node Other Builtins +@section Other built-in functions provided by GCC +@cindex built-in functions +@findex __builtin_isgreater +@findex __builtin_isgreaterequal +@findex __builtin_isless +@findex __builtin_islessequal +@findex __builtin_islessgreater +@findex __builtin_isunordered +@findex __builtin_powi +@findex __builtin_powif +@findex __builtin_powil +@findex _Exit +@findex _exit +@findex abort +@findex abs +@findex acos +@findex acosf +@findex acosh +@findex acoshf +@findex acoshl +@findex acosl +@findex alloca +@findex asin +@findex asinf +@findex asinh +@findex asinhf +@findex asinhl +@findex asinl +@findex atan +@findex atan2 +@findex atan2f +@findex atan2l +@findex atanf +@findex atanh +@findex atanhf +@findex atanhl +@findex atanl +@findex bcmp +@findex bzero +@findex cabs +@findex cabsf +@findex cabsl +@findex cacos +@findex cacosf +@findex cacosh +@findex cacoshf +@findex cacoshl +@findex cacosl +@findex calloc +@findex carg +@findex cargf +@findex cargl +@findex casin +@findex casinf +@findex casinh +@findex casinhf +@findex casinhl +@findex casinl +@findex catan +@findex catanf +@findex catanh +@findex catanhf +@findex catanhl +@findex catanl +@findex cbrt +@findex cbrtf +@findex cbrtl +@findex ccos +@findex ccosf +@findex ccosh +@findex ccoshf +@findex ccoshl +@findex ccosl +@findex ceil +@findex ceilf +@findex ceill +@findex cexp +@findex cexpf +@findex cexpl +@findex cimag +@findex cimagf +@findex cimagl +@findex clog +@findex clogf +@findex clogl +@findex conj +@findex conjf +@findex conjl +@findex copysign +@findex copysignf +@findex copysignl +@findex cos +@findex cosf +@findex cosh +@findex coshf +@findex coshl +@findex cosl +@findex cpow +@findex cpowf +@findex cpowl +@findex cproj +@findex cprojf +@findex cprojl +@findex creal +@findex crealf +@findex creall +@findex csin +@findex csinf +@findex csinh +@findex csinhf +@findex csinhl +@findex csinl +@findex csqrt +@findex csqrtf +@findex csqrtl +@findex ctan +@findex ctanf +@findex ctanh +@findex ctanhf +@findex ctanhl +@findex ctanl +@findex dcgettext +@findex dgettext +@findex drem +@findex dremf +@findex dreml +@findex erf +@findex erfc +@findex erfcf +@findex erfcl +@findex erff +@findex erfl +@findex exit +@findex exp +@findex exp10 +@findex exp10f +@findex exp10l +@findex exp2 +@findex exp2f +@findex exp2l +@findex expf +@findex expl +@findex expm1 +@findex expm1f +@findex expm1l +@findex fabs +@findex fabsf +@findex fabsl +@findex fdim +@findex fdimf +@findex fdiml +@findex ffs +@findex floor +@findex floorf +@findex floorl +@findex fma +@findex fmaf +@findex fmal +@findex fmax +@findex fmaxf +@findex fmaxl +@findex fmin +@findex fminf +@findex fminl +@findex fmod +@findex fmodf +@findex fmodl +@findex fprintf +@findex fprintf_unlocked +@findex fputs +@findex fputs_unlocked +@findex frexp +@findex frexpf +@findex frexpl +@findex fscanf +@findex gamma +@findex gammaf +@findex gammal +@findex gettext +@findex hypot +@findex hypotf +@findex hypotl +@findex ilogb +@findex ilogbf +@findex ilogbl +@findex imaxabs +@findex index +@findex isalnum +@findex isalpha +@findex isascii +@findex isblank +@findex iscntrl +@findex isdigit +@findex isgraph +@findex islower +@findex isprint +@findex ispunct +@findex isspace +@findex isupper +@findex iswalnum +@findex iswalpha +@findex iswblank +@findex iswcntrl +@findex iswdigit +@findex iswgraph +@findex iswlower +@findex iswprint +@findex iswpunct +@findex iswspace +@findex iswupper +@findex iswxdigit +@findex isxdigit +@findex j0 +@findex j0f +@findex j0l +@findex j1 +@findex j1f +@findex j1l +@findex jn +@findex jnf +@findex jnl +@findex labs +@findex ldexp +@findex ldexpf +@findex ldexpl +@findex lgamma +@findex lgammaf +@findex lgammal +@findex llabs +@findex llrint +@findex llrintf +@findex llrintl +@findex llround +@findex llroundf +@findex llroundl +@findex log +@findex log10 +@findex log10f +@findex log10l +@findex log1p +@findex log1pf +@findex log1pl +@findex log2 +@findex log2f +@findex log2l +@findex logb +@findex logbf +@findex logbl +@findex logf +@findex logl +@findex lrint +@findex lrintf +@findex lrintl +@findex lround +@findex lroundf +@findex lroundl +@findex malloc +@findex memcmp +@findex memcpy +@findex mempcpy +@findex memset +@findex modf +@findex modff +@findex modfl +@findex nearbyint +@findex nearbyintf +@findex nearbyintl +@findex nextafter +@findex nextafterf +@findex nextafterl +@findex nexttoward +@findex nexttowardf +@findex nexttowardl +@findex pow +@findex pow10 +@findex pow10f +@findex pow10l +@findex powf +@findex powl +@findex printf +@findex printf_unlocked +@findex putchar +@findex puts +@findex remainder +@findex remainderf +@findex remainderl +@findex remquo +@findex remquof +@findex remquol +@findex rindex +@findex rint +@findex rintf +@findex rintl +@findex round +@findex roundf +@findex roundl +@findex scalb +@findex scalbf +@findex scalbl +@findex scalbln +@findex scalblnf +@findex scalblnf +@findex scalbn +@findex scalbnf +@findex scanfnl +@findex signbit +@findex signbitf +@findex signbitl +@findex significand +@findex significandf +@findex significandl +@findex sin +@findex sincos +@findex sincosf +@findex sincosl +@findex sinf +@findex sinh +@findex sinhf +@findex sinhl +@findex sinl +@findex snprintf +@findex sprintf +@findex sqrt +@findex sqrtf +@findex sqrtl +@findex sscanf +@findex stpcpy +@findex stpncpy +@findex strcasecmp +@findex strcat +@findex strchr +@findex strcmp +@findex strcpy +@findex strcspn +@findex strdup +@findex strfmon +@findex strftime +@findex strlen +@findex strncasecmp +@findex strncat +@findex strncmp +@findex strncpy +@findex strndup +@findex strpbrk +@findex strrchr +@findex strspn +@findex strstr +@findex tan +@findex tanf +@findex tanh +@findex tanhf +@findex tanhl +@findex tanl +@findex tgamma +@findex tgammaf +@findex tgammal +@findex toascii +@findex tolower +@findex toupper +@findex towlower +@findex towupper +@findex trunc +@findex truncf +@findex truncl +@findex vfprintf +@findex vfscanf +@findex vprintf +@findex vscanf +@findex vsnprintf +@findex vsprintf +@findex vsscanf +@findex y0 +@findex y0f +@findex y0l +@findex y1 +@findex y1f +@findex y1l +@findex yn +@findex ynf +@findex ynl + +GCC provides a large number of built-in functions other than the ones +mentioned above. Some of these are for internal use in the processing +of exceptions or variable-length argument lists and will not be +documented here because they may change from time to time; we do not +recommend general use of these functions. + +The remaining functions are provided for optimization purposes. + +@opindex fno-builtin +GCC includes built-in versions of many of the functions in the standard +C library. The versions prefixed with @code{__builtin_} will always be +treated as having the same meaning as the C library function even if you +specify the @option{-fno-builtin} option. (@pxref{C Dialect Options}) +Many of these functions are only optimized in certain cases; if they are +not optimized in a particular case, a call to the library function will +be emitted. + +@opindex ansi +@opindex std +Outside strict ISO C mode (@option{-ansi}, @option{-std=c89} or +@option{-std=c99}), the functions +@code{_exit}, @code{alloca}, @code{bcmp}, @code{bzero}, +@code{dcgettext}, @code{dgettext}, @code{dremf}, @code{dreml}, +@code{drem}, @code{exp10f}, @code{exp10l}, @code{exp10}, @code{ffsll}, +@code{ffsl}, @code{ffs}, @code{fprintf_unlocked}, @code{fputs_unlocked}, +@code{gammaf}, @code{gammal}, @code{gamma}, @code{gettext}, +@code{index}, @code{isascii}, @code{j0f}, @code{j0l}, @code{j0}, +@code{j1f}, @code{j1l}, @code{j1}, @code{jnf}, @code{jnl}, @code{jn}, +@code{mempcpy}, @code{pow10f}, @code{pow10l}, @code{pow10}, +@code{printf_unlocked}, @code{rindex}, @code{scalbf}, @code{scalbl}, +@code{scalb}, @code{signbit}, @code{signbitf}, @code{signbitl}, +@code{significandf}, @code{significandl}, @code{significand}, +@code{sincosf}, @code{sincosl}, @code{sincos}, @code{stpcpy}, +@code{stpncpy}, @code{strcasecmp}, @code{strdup}, @code{strfmon}, +@code{strncasecmp}, @code{strndup}, @code{toascii}, @code{y0f}, +@code{y0l}, @code{y0}, @code{y1f}, @code{y1l}, @code{y1}, @code{ynf}, +@code{ynl} and @code{yn} +may be handled as built-in functions. +All these functions have corresponding versions +prefixed with @code{__builtin_}, which may be used even in strict C89 +mode. + +The ISO C99 functions +@code{_Exit}, @code{acoshf}, @code{acoshl}, @code{acosh}, @code{asinhf}, +@code{asinhl}, @code{asinh}, @code{atanhf}, @code{atanhl}, @code{atanh}, +@code{cabsf}, @code{cabsl}, @code{cabs}, @code{cacosf}, @code{cacoshf}, +@code{cacoshl}, @code{cacosh}, @code{cacosl}, @code{cacos}, +@code{cargf}, @code{cargl}, @code{carg}, @code{casinf}, @code{casinhf}, +@code{casinhl}, @code{casinh}, @code{casinl}, @code{casin}, +@code{catanf}, @code{catanhf}, @code{catanhl}, @code{catanh}, +@code{catanl}, @code{catan}, @code{cbrtf}, @code{cbrtl}, @code{cbrt}, +@code{ccosf}, @code{ccoshf}, @code{ccoshl}, @code{ccosh}, @code{ccosl}, +@code{ccos}, @code{cexpf}, @code{cexpl}, @code{cexp}, @code{cimagf}, +@code{cimagl}, @code{cimag}, @code{clogf}, @code{clogl}, @code{clog}, +@code{conjf}, @code{conjl}, @code{conj}, @code{copysignf}, @code{copysignl}, +@code{copysign}, @code{cpowf}, @code{cpowl}, @code{cpow}, @code{cprojf}, +@code{cprojl}, @code{cproj}, @code{crealf}, @code{creall}, @code{creal}, +@code{csinf}, @code{csinhf}, @code{csinhl}, @code{csinh}, @code{csinl}, +@code{csin}, @code{csqrtf}, @code{csqrtl}, @code{csqrt}, @code{ctanf}, +@code{ctanhf}, @code{ctanhl}, @code{ctanh}, @code{ctanl}, @code{ctan}, +@code{erfcf}, @code{erfcl}, @code{erfc}, @code{erff}, @code{erfl}, +@code{erf}, @code{exp2f}, @code{exp2l}, @code{exp2}, @code{expm1f}, +@code{expm1l}, @code{expm1}, @code{fdimf}, @code{fdiml}, @code{fdim}, +@code{fmaf}, @code{fmal}, @code{fmaxf}, @code{fmaxl}, @code{fmax}, +@code{fma}, @code{fminf}, @code{fminl}, @code{fmin}, @code{hypotf}, +@code{hypotl}, @code{hypot}, @code{ilogbf}, @code{ilogbl}, @code{ilogb}, +@code{imaxabs}, @code{isblank}, @code{iswblank}, @code{lgammaf}, +@code{lgammal}, @code{lgamma}, @code{llabs}, @code{llrintf}, @code{llrintl}, +@code{llrint}, @code{llroundf}, @code{llroundl}, @code{llround}, +@code{log1pf}, @code{log1pl}, @code{log1p}, @code{log2f}, @code{log2l}, +@code{log2}, @code{logbf}, @code{logbl}, @code{logb}, @code{lrintf}, +@code{lrintl}, @code{lrint}, @code{lroundf}, @code{lroundl}, +@code{lround}, @code{nearbyintf}, @code{nearbyintl}, @code{nearbyint}, +@code{nextafterf}, @code{nextafterl}, @code{nextafter}, +@code{nexttowardf}, @code{nexttowardl}, @code{nexttoward}, +@code{remainderf}, @code{remainderl}, @code{remainder}, @code{remquof}, +@code{remquol}, @code{remquo}, @code{rintf}, @code{rintl}, @code{rint}, +@code{roundf}, @code{roundl}, @code{round}, @code{scalblnf}, +@code{scalblnl}, @code{scalbln}, @code{scalbnf}, @code{scalbnl}, +@code{scalbn}, @code{snprintf}, @code{tgammaf}, @code{tgammal}, +@code{tgamma}, @code{truncf}, @code{truncl}, @code{trunc}, +@code{vfscanf}, @code{vscanf}, @code{vsnprintf} and @code{vsscanf} +are handled as built-in functions +except in strict ISO C90 mode (@option{-ansi} or @option{-std=c89}). + +There are also built-in versions of the ISO C99 functions +@code{acosf}, @code{acosl}, @code{asinf}, @code{asinl}, @code{atan2f}, +@code{atan2l}, @code{atanf}, @code{atanl}, @code{ceilf}, @code{ceill}, +@code{cosf}, @code{coshf}, @code{coshl}, @code{cosl}, @code{expf}, +@code{expl}, @code{fabsf}, @code{fabsl}, @code{floorf}, @code{floorl}, +@code{fmodf}, @code{fmodl}, @code{frexpf}, @code{frexpl}, @code{ldexpf}, +@code{ldexpl}, @code{log10f}, @code{log10l}, @code{logf}, @code{logl}, +@code{modfl}, @code{modf}, @code{powf}, @code{powl}, @code{sinf}, +@code{sinhf}, @code{sinhl}, @code{sinl}, @code{sqrtf}, @code{sqrtl}, +@code{tanf}, @code{tanhf}, @code{tanhl} and @code{tanl} +that are recognized in any mode since ISO C90 reserves these names for +the purpose to which ISO C99 puts them. All these functions have +corresponding versions prefixed with @code{__builtin_}. + +The ISO C94 functions +@code{iswalnum}, @code{iswalpha}, @code{iswcntrl}, @code{iswdigit}, +@code{iswgraph}, @code{iswlower}, @code{iswprint}, @code{iswpunct}, +@code{iswspace}, @code{iswupper}, @code{iswxdigit}, @code{towlower} and +@code{towupper} +are handled as built-in functions +except in strict ISO C90 mode (@option{-ansi} or @option{-std=c89}). + +The ISO C90 functions +@code{abort}, @code{abs}, @code{acos}, @code{asin}, @code{atan2}, +@code{atan}, @code{calloc}, @code{ceil}, @code{cosh}, @code{cos}, +@code{exit}, @code{exp}, @code{fabs}, @code{floor}, @code{fmod}, +@code{fprintf}, @code{fputs}, @code{frexp}, @code{fscanf}, +@code{isalnum}, @code{isalpha}, @code{iscntrl}, @code{isdigit}, +@code{isgraph}, @code{islower}, @code{isprint}, @code{ispunct}, +@code{isspace}, @code{isupper}, @code{isxdigit}, @code{tolower}, +@code{toupper}, @code{labs}, @code{ldexp}, @code{log10}, @code{log}, +@code{malloc}, @code{memcmp}, @code{memcpy}, @code{memset}, @code{modf}, +@code{pow}, @code{printf}, @code{putchar}, @code{puts}, @code{scanf}, +@code{sinh}, @code{sin}, @code{snprintf}, @code{sprintf}, @code{sqrt}, +@code{sscanf}, @code{strcat}, @code{strchr}, @code{strcmp}, +@code{strcpy}, @code{strcspn}, @code{strlen}, @code{strncat}, +@code{strncmp}, @code{strncpy}, @code{strpbrk}, @code{strrchr}, +@code{strspn}, @code{strstr}, @code{tanh}, @code{tan}, @code{vfprintf}, +@code{vprintf} and @code{vsprintf} +are all recognized as built-in functions unless +@option{-fno-builtin} is specified (or @option{-fno-builtin-@var{function}} +is specified for an individual function). All of these functions have +corresponding versions prefixed with @code{__builtin_}. + +GCC provides built-in versions of the ISO C99 floating point comparison +macros that avoid raising exceptions for unordered operands. They have +the same names as the standard macros ( @code{isgreater}, +@code{isgreaterequal}, @code{isless}, @code{islessequal}, +@code{islessgreater}, and @code{isunordered}) , with @code{__builtin_} +prefixed. We intend for a library implementor to be able to simply +@code{#define} each standard macro to its built-in equivalent. + +@deftypefn {Built-in Function} int __builtin_types_compatible_p (@var{type1}, @var{type2}) + +You can use the built-in function @code{__builtin_types_compatible_p} to +determine whether two types are the same. + +This built-in function returns 1 if the unqualified versions of the +types @var{type1} and @var{type2} (which are types, not expressions) are +compatible, 0 otherwise. The result of this built-in function can be +used in integer constant expressions. + +This built-in function ignores top level qualifiers (e.g., @code{const}, +@code{volatile}). For example, @code{int} is equivalent to @code{const +int}. + +The type @code{int[]} and @code{int[5]} are compatible. On the other +hand, @code{int} and @code{char *} are not compatible, even if the size +of their types, on the particular architecture are the same. Also, the +amount of pointer indirection is taken into account when determining +similarity. Consequently, @code{short *} is not similar to +@code{short **}. Furthermore, two types that are typedefed are +considered compatible if their underlying types are compatible. + +An @code{enum} type is not considered to be compatible with another +@code{enum} type even if both are compatible with the same integer +type; this is what the C standard specifies. +For example, @code{enum @{foo, bar@}} is not similar to +@code{enum @{hot, dog@}}. + +You would typically use this function in code whose execution varies +depending on the arguments' types. For example: + +@smallexample +#define foo(x) \ + (@{ \ + typeof (x) tmp = (x); \ + if (__builtin_types_compatible_p (typeof (x), long double)) \ + tmp = foo_long_double (tmp); \ + else if (__builtin_types_compatible_p (typeof (x), double)) \ + tmp = foo_double (tmp); \ + else if (__builtin_types_compatible_p (typeof (x), float)) \ + tmp = foo_float (tmp); \ + else \ + abort (); \ + tmp; \ + @}) +@end smallexample + +@emph{Note:} This construct is only available for C@. + +@end deftypefn + +@deftypefn {Built-in Function} @var{type} __builtin_choose_expr (@var{const_exp}, @var{exp1}, @var{exp2}) + +You can use the built-in function @code{__builtin_choose_expr} to +evaluate code depending on the value of a constant expression. This +built-in function returns @var{exp1} if @var{const_exp}, which is a +constant expression that must be able to be determined at compile time, +is nonzero. Otherwise it returns 0. + +This built-in function is analogous to the @samp{? :} operator in C, +except that the expression returned has its type unaltered by promotion +rules. Also, the built-in function does not evaluate the expression +that was not chosen. For example, if @var{const_exp} evaluates to true, +@var{exp2} is not evaluated even if it has side-effects. + +This built-in function can return an lvalue if the chosen argument is an +lvalue. + +If @var{exp1} is returned, the return type is the same as @var{exp1}'s +type. Similarly, if @var{exp2} is returned, its return type is the same +as @var{exp2}. + +Example: + +@smallexample +#define foo(x) \ + __builtin_choose_expr ( \ + __builtin_types_compatible_p (typeof (x), double), \ + foo_double (x), \ + __builtin_choose_expr ( \ + __builtin_types_compatible_p (typeof (x), float), \ + foo_float (x), \ + /* @r{The void expression results in a compile-time error} \ + @r{when assigning the result to something.} */ \ + (void)0)) +@end smallexample + +@emph{Note:} This construct is only available for C@. Furthermore, the +unused expression (@var{exp1} or @var{exp2} depending on the value of +@var{const_exp}) may still generate syntax errors. This may change in +future revisions. + +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_constant_p (@var{exp}) +You can use the built-in function @code{__builtin_constant_p} to +determine if a value is known to be constant at compile-time and hence +that GCC can perform constant-folding on expressions involving that +value. The argument of the function is the value to test. The function +returns the integer 1 if the argument is known to be a compile-time +constant and 0 if it is not known to be a compile-time constant. A +return of 0 does not indicate that the value is @emph{not} a constant, +but merely that GCC cannot prove it is a constant with the specified +value of the @option{-O} option. + +You would typically use this function in an embedded application where +memory was a critical resource. If you have some complex calculation, +you may want it to be folded if it involves constants, but need to call +a function if it does not. For example: + +@smallexample +#define Scale_Value(X) \ + (__builtin_constant_p (X) \ + ? ((X) * SCALE + OFFSET) : Scale (X)) +@end smallexample + +You may use this built-in function in either a macro or an inline +function. However, if you use it in an inlined function and pass an +argument of the function as the argument to the built-in, GCC will +never return 1 when you call the inline function with a string constant +or compound literal (@pxref{Compound Literals}) and will not return 1 +when you pass a constant numeric value to the inline function unless you +specify the @option{-O} option. + +You may also use @code{__builtin_constant_p} in initializers for static +data. For instance, you can write + +@smallexample +static const int table[] = @{ + __builtin_constant_p (EXPRESSION) ? (EXPRESSION) : -1, + /* @r{@dots{}} */ +@}; +@end smallexample + +@noindent +This is an acceptable initializer even if @var{EXPRESSION} is not a +constant expression. GCC must be more conservative about evaluating the +built-in in this case, because it has no opportunity to perform +optimization. + +Previous versions of GCC did not accept this built-in in data +initializers. The earliest version where it is completely safe is +3.0.1. +@end deftypefn + +@deftypefn {Built-in Function} long __builtin_expect (long @var{exp}, long @var{c}) +@opindex fprofile-arcs +You may use @code{__builtin_expect} to provide the compiler with +branch prediction information. In general, you should prefer to +use actual profile feedback for this (@option{-fprofile-arcs}), as +programmers are notoriously bad at predicting how their programs +actually perform. However, there are applications in which this +data is hard to collect. + +The return value is the value of @var{exp}, which should be an +integral expression. The value of @var{c} must be a compile-time +constant. The semantics of the built-in are that it is expected +that @var{exp} == @var{c}. For example: + +@smallexample +if (__builtin_expect (x, 0)) + foo (); +@end smallexample + +@noindent +would indicate that we do not expect to call @code{foo}, since +we expect @code{x} to be zero. Since you are limited to integral +expressions for @var{exp}, you should use constructions such as + +@smallexample +if (__builtin_expect (ptr != NULL, 1)) + error (); +@end smallexample + +@noindent +when testing pointer or floating-point values. +@end deftypefn + +@deftypefn {Built-in Function} void __builtin_prefetch (const void *@var{addr}, ...) +This function is used to minimize cache-miss latency by moving data into +a cache before it is accessed. +You can insert calls to @code{__builtin_prefetch} into code for which +you know addresses of data in memory that is likely to be accessed soon. +If the target supports them, data prefetch instructions will be generated. +If the prefetch is done early enough before the access then the data will +be in the cache by the time it is accessed. + +The value of @var{addr} is the address of the memory to prefetch. +There are two optional arguments, @var{rw} and @var{locality}. +The value of @var{rw} is a compile-time constant one or zero; one +means that the prefetch is preparing for a write to the memory address +and zero, the default, means that the prefetch is preparing for a read. +The value @var{locality} must be a compile-time constant integer between +zero and three. A value of zero means that the data has no temporal +locality, so it need not be left in the cache after the access. A value +of three means that the data has a high degree of temporal locality and +should be left in all levels of cache possible. Values of one and two +mean, respectively, a low or moderate degree of temporal locality. The +default is three. + +@smallexample +for (i = 0; i < n; i++) + @{ + a[i] = a[i] + b[i]; + __builtin_prefetch (&a[i+j], 1, 1); + __builtin_prefetch (&b[i+j], 0, 1); + /* @r{@dots{}} */ + @} +@end smallexample + +Data prefetch does not generate faults if @var{addr} is invalid, but +the address expression itself must be valid. For example, a prefetch +of @code{p->next} will not fault if @code{p->next} is not a valid +address, but evaluation will fault if @code{p} is not a valid address. + +If the target does not support data prefetch, the address expression +is evaluated if it includes side effects but no other code is generated +and GCC does not issue a warning. +@end deftypefn + +@deftypefn {Built-in Function} double __builtin_huge_val (void) +Returns a positive infinity, if supported by the floating-point format, +else @code{DBL_MAX}. This function is suitable for implementing the +ISO C macro @code{HUGE_VAL}. +@end deftypefn + +@deftypefn {Built-in Function} float __builtin_huge_valf (void) +Similar to @code{__builtin_huge_val}, except the return type is @code{float}. +@end deftypefn + +@deftypefn {Built-in Function} {long double} __builtin_huge_vall (void) +Similar to @code{__builtin_huge_val}, except the return +type is @code{long double}. +@end deftypefn + +@deftypefn {Built-in Function} double __builtin_inf (void) +Similar to @code{__builtin_huge_val}, except a warning is generated +if the target floating-point format does not support infinities. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal32 __builtin_infd32 (void) +Similar to @code{__builtin_inf}, except the return type is @code{_Decimal32}. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal64 __builtin_infd64 (void) +Similar to @code{__builtin_inf}, except the return type is @code{_Decimal64}. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal128 __builtin_infd128 (void) +Similar to @code{__builtin_inf}, except the return type is @code{_Decimal128}. +@end deftypefn + +@deftypefn {Built-in Function} float __builtin_inff (void) +Similar to @code{__builtin_inf}, except the return type is @code{float}. +This function is suitable for implementing the ISO C99 macro @code{INFINITY}. +@end deftypefn + +@deftypefn {Built-in Function} {long double} __builtin_infl (void) +Similar to @code{__builtin_inf}, except the return +type is @code{long double}. +@end deftypefn + +@deftypefn {Built-in Function} double __builtin_nan (const char *str) +This is an implementation of the ISO C99 function @code{nan}. + +Since ISO C99 defines this function in terms of @code{strtod}, which we +do not implement, a description of the parsing is in order. The string +is parsed as by @code{strtol}; that is, the base is recognized by +leading @samp{0} or @samp{0x} prefixes. The number parsed is placed +in the significand such that the least significant bit of the number +is at the least significant bit of the significand. The number is +truncated to fit the significand field provided. The significand is +forced to be a quiet NaN@. + +This function, if given a string literal all of which would have been +consumed by strtol, is evaluated early enough that it is considered a +compile-time constant. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal32 __builtin_nand32 (const char *str) +Similar to @code{__builtin_nan}, except the return type is @code{_Decimal32}. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal64 __builtin_nand64 (const char *str) +Similar to @code{__builtin_nan}, except the return type is @code{_Decimal64}. +@end deftypefn + +@deftypefn {Built-in Function} _Decimal128 __builtin_nand128 (const char *str) +Similar to @code{__builtin_nan}, except the return type is @code{_Decimal128}. +@end deftypefn + +@deftypefn {Built-in Function} float __builtin_nanf (const char *str) +Similar to @code{__builtin_nan}, except the return type is @code{float}. +@end deftypefn + +@deftypefn {Built-in Function} {long double} __builtin_nanl (const char *str) +Similar to @code{__builtin_nan}, except the return type is @code{long double}. +@end deftypefn + +@deftypefn {Built-in Function} double __builtin_nans (const char *str) +Similar to @code{__builtin_nan}, except the significand is forced +to be a signaling NaN@. The @code{nans} function is proposed by +@uref{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n965.htm,,WG14 N965}. +@end deftypefn + +@deftypefn {Built-in Function} float __builtin_nansf (const char *str) +Similar to @code{__builtin_nans}, except the return type is @code{float}. +@end deftypefn + +@deftypefn {Built-in Function} {long double} __builtin_nansl (const char *str) +Similar to @code{__builtin_nans}, except the return type is @code{long double}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ffs (unsigned int x) +Returns one plus the index of the least significant 1-bit of @var{x}, or +if @var{x} is zero, returns zero. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_clz (unsigned int x) +Returns the number of leading 0-bits in @var{x}, starting at the most +significant bit position. If @var{x} is 0, the result is undefined. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ctz (unsigned int x) +Returns the number of trailing 0-bits in @var{x}, starting at the least +significant bit position. If @var{x} is 0, the result is undefined. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_popcount (unsigned int x) +Returns the number of 1-bits in @var{x}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_parity (unsigned int x) +Returns the parity of @var{x}, i.e.@: the number of 1-bits in @var{x} +modulo 2. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ffsl (unsigned long) +Similar to @code{__builtin_ffs}, except the argument type is +@code{unsigned long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_clzl (unsigned long) +Similar to @code{__builtin_clz}, except the argument type is +@code{unsigned long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ctzl (unsigned long) +Similar to @code{__builtin_ctz}, except the argument type is +@code{unsigned long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_popcountl (unsigned long) +Similar to @code{__builtin_popcount}, except the argument type is +@code{unsigned long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_parityl (unsigned long) +Similar to @code{__builtin_parity}, except the argument type is +@code{unsigned long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ffsll (unsigned long long) +Similar to @code{__builtin_ffs}, except the argument type is +@code{unsigned long long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_clzll (unsigned long long) +Similar to @code{__builtin_clz}, except the argument type is +@code{unsigned long long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_ctzll (unsigned long long) +Similar to @code{__builtin_ctz}, except the argument type is +@code{unsigned long long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_popcountll (unsigned long long) +Similar to @code{__builtin_popcount}, except the argument type is +@code{unsigned long long}. +@end deftypefn + +@deftypefn {Built-in Function} int __builtin_parityll (unsigned long long) +Similar to @code{__builtin_parity}, except the argument type is +@code{unsigned long long}. +@end deftypefn + +@deftypefn {Built-in Function} double __builtin_powi (double, int) +Returns the first argument raised to the power of the second. Unlike the +@code{pow} function no guarantees about precision and rounding are made. +@end deftypefn + +@deftypefn {Built-in Function} float __builtin_powif (float, int) +Similar to @code{__builtin_powi}, except the argument and return types +are @code{float}. +@end deftypefn + +@deftypefn {Built-in Function} {long double} __builtin_powil (long double, int) +Similar to @code{__builtin_powi}, except the argument and return types +are @code{long double}. +@end deftypefn +@c APPLE LOCAL begin mainline +@deftypefn {Built-in Function} int32_t __builtin_bswap32 (int32_t x) +Returns @var{x} with the order of the bytes reversed; for example, +@code{0xaabbccdd} becomes @code{0xddccbbaa}. Byte here always means +exactly 8 bits. +@end deftypefn + +@deftypefn {Built-in Function} int64_t __builtin_bswap64 (int64_t x) +Similar to @code{__builtin_bswap32}, except the argument and return types +are 64-bit. +@end deftypefn +@c APPLE LOCAL end mainline + +@node Target Builtins +@section Built-in Functions Specific to Particular Target Machines + +On some target machines, GCC supports many built-in functions specific +to those machines. Generally these generate calls to specific machine +instructions, but allow the compiler to schedule those calls. + +@c APPLE LOCAL begin ARM NEON support. Merge from Codesourcery +@menu +* Alpha Built-in Functions:: +* ARM Built-in Functions:: +* ARM NEON Intrinsics:: +* Blackfin Built-in Functions:: +* FR-V Built-in Functions:: +* X86 Built-in Functions:: +* MIPS DSP Built-in Functions:: +* MIPS Paired-Single Support:: +* PowerPC AltiVec Built-in Functions:: +* SPARC VIS Built-in Functions:: +@end menu +@c APPLE LOCAL end ARM NEON support. Merge from Codesourcery + +@node Alpha Built-in Functions +@subsection Alpha Built-in Functions + +These built-in functions are available for the Alpha family of +processors, depending on the command-line switches used. + +The following built-in functions are always available. They +all generate the machine instruction that is part of the name. + +@smallexample +long __builtin_alpha_implver (void) +long __builtin_alpha_rpcc (void) +long __builtin_alpha_amask (long) +long __builtin_alpha_cmpbge (long, long) +long __builtin_alpha_extbl (long, long) +long __builtin_alpha_extwl (long, long) +long __builtin_alpha_extll (long, long) +long __builtin_alpha_extql (long, long) +long __builtin_alpha_extwh (long, long) +long __builtin_alpha_extlh (long, long) +long __builtin_alpha_extqh (long, long) +long __builtin_alpha_insbl (long, long) +long __builtin_alpha_inswl (long, long) +long __builtin_alpha_insll (long, long) +long __builtin_alpha_insql (long, long) +long __builtin_alpha_inswh (long, long) +long __builtin_alpha_inslh (long, long) +long __builtin_alpha_insqh (long, long) +long __builtin_alpha_mskbl (long, long) +long __builtin_alpha_mskwl (long, long) +long __builtin_alpha_mskll (long, long) +long __builtin_alpha_mskql (long, long) +long __builtin_alpha_mskwh (long, long) +long __builtin_alpha_msklh (long, long) +long __builtin_alpha_mskqh (long, long) +long __builtin_alpha_umulh (long, long) +long __builtin_alpha_zap (long, long) +long __builtin_alpha_zapnot (long, long) +@end smallexample + +The following built-in functions are always with @option{-mmax} +or @option{-mcpu=@var{cpu}} where @var{cpu} is @code{pca56} or +later. They all generate the machine instruction that is part +of the name. + +@smallexample +long __builtin_alpha_pklb (long) +long __builtin_alpha_pkwb (long) +long __builtin_alpha_unpkbl (long) +long __builtin_alpha_unpkbw (long) +long __builtin_alpha_minub8 (long, long) +long __builtin_alpha_minsb8 (long, long) +long __builtin_alpha_minuw4 (long, long) +long __builtin_alpha_minsw4 (long, long) +long __builtin_alpha_maxub8 (long, long) +long __builtin_alpha_maxsb8 (long, long) +long __builtin_alpha_maxuw4 (long, long) +long __builtin_alpha_maxsw4 (long, long) +long __builtin_alpha_perr (long, long) +@end smallexample + +The following built-in functions are always with @option{-mcix} +or @option{-mcpu=@var{cpu}} where @var{cpu} is @code{ev67} or +later. They all generate the machine instruction that is part +of the name. + +@smallexample +long __builtin_alpha_cttz (long) +long __builtin_alpha_ctlz (long) +long __builtin_alpha_ctpop (long) +@end smallexample + +The following builtins are available on systems that use the OSF/1 +PALcode. Normally they invoke the @code{rduniq} and @code{wruniq} +PAL calls, but when invoked with @option{-mtls-kernel}, they invoke +@code{rdval} and @code{wrval}. + +@smallexample +void *__builtin_thread_pointer (void) +void __builtin_set_thread_pointer (void *) +@end smallexample + +@node ARM Built-in Functions +@subsection ARM Built-in Functions + +These built-in functions are available for the ARM family of +processors, when the @option{-mcpu=iwmmxt} switch is used: + +@smallexample +typedef int v2si __attribute__ ((vector_size (8))); +typedef short v4hi __attribute__ ((vector_size (8))); +typedef char v8qi __attribute__ ((vector_size (8))); + +int __builtin_arm_getwcx (int) +void __builtin_arm_setwcx (int, int) +int __builtin_arm_textrmsb (v8qi, int) +int __builtin_arm_textrmsh (v4hi, int) +int __builtin_arm_textrmsw (v2si, int) +int __builtin_arm_textrmub (v8qi, int) +int __builtin_arm_textrmuh (v4hi, int) +int __builtin_arm_textrmuw (v2si, int) +v8qi __builtin_arm_tinsrb (v8qi, int) +v4hi __builtin_arm_tinsrh (v4hi, int) +v2si __builtin_arm_tinsrw (v2si, int) +long long __builtin_arm_tmia (long long, int, int) +long long __builtin_arm_tmiabb (long long, int, int) +long long __builtin_arm_tmiabt (long long, int, int) +long long __builtin_arm_tmiaph (long long, int, int) +long long __builtin_arm_tmiatb (long long, int, int) +long long __builtin_arm_tmiatt (long long, int, int) +int __builtin_arm_tmovmskb (v8qi) +int __builtin_arm_tmovmskh (v4hi) +int __builtin_arm_tmovmskw (v2si) +long long __builtin_arm_waccb (v8qi) +long long __builtin_arm_wacch (v4hi) +long long __builtin_arm_waccw (v2si) +v8qi __builtin_arm_waddb (v8qi, v8qi) +v8qi __builtin_arm_waddbss (v8qi, v8qi) +v8qi __builtin_arm_waddbus (v8qi, v8qi) +v4hi __builtin_arm_waddh (v4hi, v4hi) +v4hi __builtin_arm_waddhss (v4hi, v4hi) +v4hi __builtin_arm_waddhus (v4hi, v4hi) +v2si __builtin_arm_waddw (v2si, v2si) +v2si __builtin_arm_waddwss (v2si, v2si) +v2si __builtin_arm_waddwus (v2si, v2si) +v8qi __builtin_arm_walign (v8qi, v8qi, int) +long long __builtin_arm_wand(long long, long long) +long long __builtin_arm_wandn (long long, long long) +v8qi __builtin_arm_wavg2b (v8qi, v8qi) +v8qi __builtin_arm_wavg2br (v8qi, v8qi) +v4hi __builtin_arm_wavg2h (v4hi, v4hi) +v4hi __builtin_arm_wavg2hr (v4hi, v4hi) +v8qi __builtin_arm_wcmpeqb (v8qi, v8qi) +v4hi __builtin_arm_wcmpeqh (v4hi, v4hi) +v2si __builtin_arm_wcmpeqw (v2si, v2si) +v8qi __builtin_arm_wcmpgtsb (v8qi, v8qi) +v4hi __builtin_arm_wcmpgtsh (v4hi, v4hi) +v2si __builtin_arm_wcmpgtsw (v2si, v2si) +v8qi __builtin_arm_wcmpgtub (v8qi, v8qi) +v4hi __builtin_arm_wcmpgtuh (v4hi, v4hi) +v2si __builtin_arm_wcmpgtuw (v2si, v2si) +long long __builtin_arm_wmacs (long long, v4hi, v4hi) +long long __builtin_arm_wmacsz (v4hi, v4hi) +long long __builtin_arm_wmacu (long long, v4hi, v4hi) +long long __builtin_arm_wmacuz (v4hi, v4hi) +v4hi __builtin_arm_wmadds (v4hi, v4hi) +v4hi __builtin_arm_wmaddu (v4hi, v4hi) +v8qi __builtin_arm_wmaxsb (v8qi, v8qi) +v4hi __builtin_arm_wmaxsh (v4hi, v4hi) +v2si __builtin_arm_wmaxsw (v2si, v2si) +v8qi __builtin_arm_wmaxub (v8qi, v8qi) +v4hi __builtin_arm_wmaxuh (v4hi, v4hi) +v2si __builtin_arm_wmaxuw (v2si, v2si) +v8qi __builtin_arm_wminsb (v8qi, v8qi) +v4hi __builtin_arm_wminsh (v4hi, v4hi) +v2si __builtin_arm_wminsw (v2si, v2si) +v8qi __builtin_arm_wminub (v8qi, v8qi) +v4hi __builtin_arm_wminuh (v4hi, v4hi) +v2si __builtin_arm_wminuw (v2si, v2si) +v4hi __builtin_arm_wmulsm (v4hi, v4hi) +v4hi __builtin_arm_wmulul (v4hi, v4hi) +v4hi __builtin_arm_wmulum (v4hi, v4hi) +long long __builtin_arm_wor (long long, long long) +v2si __builtin_arm_wpackdss (long long, long long) +v2si __builtin_arm_wpackdus (long long, long long) +v8qi __builtin_arm_wpackhss (v4hi, v4hi) +v8qi __builtin_arm_wpackhus (v4hi, v4hi) +v4hi __builtin_arm_wpackwss (v2si, v2si) +v4hi __builtin_arm_wpackwus (v2si, v2si) +long long __builtin_arm_wrord (long long, long long) +long long __builtin_arm_wrordi (long long, int) +v4hi __builtin_arm_wrorh (v4hi, long long) +v4hi __builtin_arm_wrorhi (v4hi, int) +v2si __builtin_arm_wrorw (v2si, long long) +v2si __builtin_arm_wrorwi (v2si, int) +v2si __builtin_arm_wsadb (v8qi, v8qi) +v2si __builtin_arm_wsadbz (v8qi, v8qi) +v2si __builtin_arm_wsadh (v4hi, v4hi) +v2si __builtin_arm_wsadhz (v4hi, v4hi) +v4hi __builtin_arm_wshufh (v4hi, int) +long long __builtin_arm_wslld (long long, long long) +long long __builtin_arm_wslldi (long long, int) +v4hi __builtin_arm_wsllh (v4hi, long long) +v4hi __builtin_arm_wsllhi (v4hi, int) +v2si __builtin_arm_wsllw (v2si, long long) +v2si __builtin_arm_wsllwi (v2si, int) +long long __builtin_arm_wsrad (long long, long long) +long long __builtin_arm_wsradi (long long, int) +v4hi __builtin_arm_wsrah (v4hi, long long) +v4hi __builtin_arm_wsrahi (v4hi, int) +v2si __builtin_arm_wsraw (v2si, long long) +v2si __builtin_arm_wsrawi (v2si, int) +long long __builtin_arm_wsrld (long long, long long) +long long __builtin_arm_wsrldi (long long, int) +v4hi __builtin_arm_wsrlh (v4hi, long long) +v4hi __builtin_arm_wsrlhi (v4hi, int) +v2si __builtin_arm_wsrlw (v2si, long long) +v2si __builtin_arm_wsrlwi (v2si, int) +v8qi __builtin_arm_wsubb (v8qi, v8qi) +v8qi __builtin_arm_wsubbss (v8qi, v8qi) +v8qi __builtin_arm_wsubbus (v8qi, v8qi) +v4hi __builtin_arm_wsubh (v4hi, v4hi) +v4hi __builtin_arm_wsubhss (v4hi, v4hi) +v4hi __builtin_arm_wsubhus (v4hi, v4hi) +v2si __builtin_arm_wsubw (v2si, v2si) +v2si __builtin_arm_wsubwss (v2si, v2si) +v2si __builtin_arm_wsubwus (v2si, v2si) +v4hi __builtin_arm_wunpckehsb (v8qi) +v2si __builtin_arm_wunpckehsh (v4hi) +long long __builtin_arm_wunpckehsw (v2si) +v4hi __builtin_arm_wunpckehub (v8qi) +v2si __builtin_arm_wunpckehuh (v4hi) +long long __builtin_arm_wunpckehuw (v2si) +v4hi __builtin_arm_wunpckelsb (v8qi) +v2si __builtin_arm_wunpckelsh (v4hi) +long long __builtin_arm_wunpckelsw (v2si) +v4hi __builtin_arm_wunpckelub (v8qi) +v2si __builtin_arm_wunpckeluh (v4hi) +long long __builtin_arm_wunpckeluw (v2si) +v8qi __builtin_arm_wunpckihb (v8qi, v8qi) +v4hi __builtin_arm_wunpckihh (v4hi, v4hi) +v2si __builtin_arm_wunpckihw (v2si, v2si) +v8qi __builtin_arm_wunpckilb (v8qi, v8qi) +v4hi __builtin_arm_wunpckilh (v4hi, v4hi) +v2si __builtin_arm_wunpckilw (v2si, v2si) +long long __builtin_arm_wxor (long long, long long) +long long __builtin_arm_wzero () +@end smallexample + +@c APPLE LOCAL begin ARM NEON support +@node ARM NEON Intrinsics +@subsection ARM NEON Intrinsics + +These built-in intrinsics for the ARM Advanced SIMD extension are available +when the @option{-mfpu=neon} switch is used: + +@include arm-neon-intrinsics.texi +@c APPLE LOCAL end ARM NEON support. Merge from Codesourcery. + +@node Blackfin Built-in Functions +@subsection Blackfin Built-in Functions + +Currently, there are two Blackfin-specific built-in functions. These are +used for generating @code{CSYNC} and @code{SSYNC} machine insns without +using inline assembly; by using these built-in functions the compiler can +automatically add workarounds for hardware errata involving these +instructions. These functions are named as follows: + +@smallexample +void __builtin_bfin_csync (void) +void __builtin_bfin_ssync (void) +@end smallexample + +@node FR-V Built-in Functions +@subsection FR-V Built-in Functions + +GCC provides many FR-V-specific built-in functions. In general, +these functions are intended to be compatible with those described +by @cite{FR-V Family, Softune C/C++ Compiler Manual (V6), Fujitsu +Semiconductor}. The two exceptions are @code{__MDUNPACKH} and +@code{__MBTOHE}, the gcc forms of which pass 128-bit values by +pointer rather than by value. + +Most of the functions are named after specific FR-V instructions. +Such functions are said to be ``directly mapped'' and are summarized +here in tabular form. + +@menu +* Argument Types:: +* Directly-mapped Integer Functions:: +* Directly-mapped Media Functions:: +* Raw read/write Functions:: +* Other Built-in Functions:: +@end menu + +@node Argument Types +@subsubsection Argument Types + +The arguments to the built-in functions can be divided into three groups: +register numbers, compile-time constants and run-time values. In order +to make this classification clear at a glance, the arguments and return +values are given the following pseudo types: + +@multitable @columnfractions .20 .30 .15 .35 +@item Pseudo type @tab Real C type @tab Constant? @tab Description +@item @code{uh} @tab @code{unsigned short} @tab No @tab an unsigned halfword +@item @code{uw1} @tab @code{unsigned int} @tab No @tab an unsigned word +@item @code{sw1} @tab @code{int} @tab No @tab a signed word +@item @code{uw2} @tab @code{unsigned long long} @tab No +@tab an unsigned doubleword +@item @code{sw2} @tab @code{long long} @tab No @tab a signed doubleword +@item @code{const} @tab @code{int} @tab Yes @tab an integer constant +@item @code{acc} @tab @code{int} @tab Yes @tab an ACC register number +@item @code{iacc} @tab @code{int} @tab Yes @tab an IACC register number +@end multitable + +These pseudo types are not defined by GCC, they are simply a notational +convenience used in this manual. + +Arguments of type @code{uh}, @code{uw1}, @code{sw1}, @code{uw2} +and @code{sw2} are evaluated at run time. They correspond to +register operands in the underlying FR-V instructions. + +@code{const} arguments represent immediate operands in the underlying +FR-V instructions. They must be compile-time constants. + +@code{acc} arguments are evaluated at compile time and specify the number +of an accumulator register. For example, an @code{acc} argument of 2 +will select the ACC2 register. + +@code{iacc} arguments are similar to @code{acc} arguments but specify the +number of an IACC register. See @pxref{Other Built-in Functions} +for more details. + +@node Directly-mapped Integer Functions +@subsubsection Directly-mapped Integer Functions + +The functions listed below map directly to FR-V I-type instructions. + +@multitable @columnfractions .45 .32 .23 +@item Function prototype @tab Example usage @tab Assembly output +@item @code{sw1 __ADDSS (sw1, sw1)} +@tab @code{@var{c} = __ADDSS (@var{a}, @var{b})} +@tab @code{ADDSS @var{a},@var{b},@var{c}} +@item @code{sw1 __SCAN (sw1, sw1)} +@tab @code{@var{c} = __SCAN (@var{a}, @var{b})} +@tab @code{SCAN @var{a},@var{b},@var{c}} +@item @code{sw1 __SCUTSS (sw1)} +@tab @code{@var{b} = __SCUTSS (@var{a})} +@tab @code{SCUTSS @var{a},@var{b}} +@item @code{sw1 __SLASS (sw1, sw1)} +@tab @code{@var{c} = __SLASS (@var{a}, @var{b})} +@tab @code{SLASS @var{a},@var{b},@var{c}} +@item @code{void __SMASS (sw1, sw1)} +@tab @code{__SMASS (@var{a}, @var{b})} +@tab @code{SMASS @var{a},@var{b}} +@item @code{void __SMSSS (sw1, sw1)} +@tab @code{__SMSSS (@var{a}, @var{b})} +@tab @code{SMSSS @var{a},@var{b}} +@item @code{void __SMU (sw1, sw1)} +@tab @code{__SMU (@var{a}, @var{b})} +@tab @code{SMU @var{a},@var{b}} +@item @code{sw2 __SMUL (sw1, sw1)} +@tab @code{@var{c} = __SMUL (@var{a}, @var{b})} +@tab @code{SMUL @var{a},@var{b},@var{c}} +@item @code{sw1 __SUBSS (sw1, sw1)} +@tab @code{@var{c} = __SUBSS (@var{a}, @var{b})} +@tab @code{SUBSS @var{a},@var{b},@var{c}} +@item @code{uw2 __UMUL (uw1, uw1)} +@tab @code{@var{c} = __UMUL (@var{a}, @var{b})} +@tab @code{UMUL @var{a},@var{b},@var{c}} +@end multitable + +@node Directly-mapped Media Functions +@subsubsection Directly-mapped Media Functions + +The functions listed below map directly to FR-V M-type instructions. + +@multitable @columnfractions .45 .32 .23 +@item Function prototype @tab Example usage @tab Assembly output +@item @code{uw1 __MABSHS (sw1)} +@tab @code{@var{b} = __MABSHS (@var{a})} +@tab @code{MABSHS @var{a},@var{b}} +@item @code{void __MADDACCS (acc, acc)} +@tab @code{__MADDACCS (@var{b}, @var{a})} +@tab @code{MADDACCS @var{a},@var{b}} +@item @code{sw1 __MADDHSS (sw1, sw1)} +@tab @code{@var{c} = __MADDHSS (@var{a}, @var{b})} +@tab @code{MADDHSS @var{a},@var{b},@var{c}} +@item @code{uw1 __MADDHUS (uw1, uw1)} +@tab @code{@var{c} = __MADDHUS (@var{a}, @var{b})} +@tab @code{MADDHUS @var{a},@var{b},@var{c}} +@item @code{uw1 __MAND (uw1, uw1)} +@tab @code{@var{c} = __MAND (@var{a}, @var{b})} +@tab @code{MAND @var{a},@var{b},@var{c}} +@item @code{void __MASACCS (acc, acc)} +@tab @code{__MASACCS (@var{b}, @var{a})} +@tab @code{MASACCS @var{a},@var{b}} +@item @code{uw1 __MAVEH (uw1, uw1)} +@tab @code{@var{c} = __MAVEH (@var{a}, @var{b})} +@tab @code{MAVEH @var{a},@var{b},@var{c}} +@item @code{uw2 __MBTOH (uw1)} +@tab @code{@var{b} = __MBTOH (@var{a})} +@tab @code{MBTOH @var{a},@var{b}} +@item @code{void __MBTOHE (uw1 *, uw1)} +@tab @code{__MBTOHE (&@var{b}, @var{a})} +@tab @code{MBTOHE @var{a},@var{b}} +@item @code{void __MCLRACC (acc)} +@tab @code{__MCLRACC (@var{a})} +@tab @code{MCLRACC @var{a}} +@item @code{void __MCLRACCA (void)} +@tab @code{__MCLRACCA ()} +@tab @code{MCLRACCA} +@item @code{uw1 __Mcop1 (uw1, uw1)} +@tab @code{@var{c} = __Mcop1 (@var{a}, @var{b})} +@tab @code{Mcop1 @var{a},@var{b},@var{c}} +@item @code{uw1 __Mcop2 (uw1, uw1)} +@tab @code{@var{c} = __Mcop2 (@var{a}, @var{b})} +@tab @code{Mcop2 @var{a},@var{b},@var{c}} +@item @code{uw1 __MCPLHI (uw2, const)} +@tab @code{@var{c} = __MCPLHI (@var{a}, @var{b})} +@tab @code{MCPLHI @var{a},#@var{b},@var{c}} +@item @code{uw1 __MCPLI (uw2, const)} +@tab @code{@var{c} = __MCPLI (@var{a}, @var{b})} +@tab @code{MCPLI @var{a},#@var{b},@var{c}} +@item @code{void __MCPXIS (acc, sw1, sw1)} +@tab @code{__MCPXIS (@var{c}, @var{a}, @var{b})} +@tab @code{MCPXIS @var{a},@var{b},@var{c}} +@item @code{void __MCPXIU (acc, uw1, uw1)} +@tab @code{__MCPXIU (@var{c}, @var{a}, @var{b})} +@tab @code{MCPXIU @var{a},@var{b},@var{c}} +@item @code{void __MCPXRS (acc, sw1, sw1)} +@tab @code{__MCPXRS (@var{c}, @var{a}, @var{b})} +@tab @code{MCPXRS @var{a},@var{b},@var{c}} +@item @code{void __MCPXRU (acc, uw1, uw1)} +@tab @code{__MCPXRU (@var{c}, @var{a}, @var{b})} +@tab @code{MCPXRU @var{a},@var{b},@var{c}} +@item @code{uw1 __MCUT (acc, uw1)} +@tab @code{@var{c} = __MCUT (@var{a}, @var{b})} +@tab @code{MCUT @var{a},@var{b},@var{c}} +@item @code{uw1 __MCUTSS (acc, sw1)} +@tab @code{@var{c} = __MCUTSS (@var{a}, @var{b})} +@tab @code{MCUTSS @var{a},@var{b},@var{c}} +@item @code{void __MDADDACCS (acc, acc)} +@tab @code{__MDADDACCS (@var{b}, @var{a})} +@tab @code{MDADDACCS @var{a},@var{b}} +@item @code{void __MDASACCS (acc, acc)} +@tab @code{__MDASACCS (@var{b}, @var{a})} +@tab @code{MDASACCS @var{a},@var{b}} +@item @code{uw2 __MDCUTSSI (acc, const)} +@tab @code{@var{c} = __MDCUTSSI (@var{a}, @var{b})} +@tab @code{MDCUTSSI @var{a},#@var{b},@var{c}} +@item @code{uw2 __MDPACKH (uw2, uw2)} +@tab @code{@var{c} = __MDPACKH (@var{a}, @var{b})} +@tab @code{MDPACKH @var{a},@var{b},@var{c}} +@item @code{uw2 __MDROTLI (uw2, const)} +@tab @code{@var{c} = __MDROTLI (@var{a}, @var{b})} +@tab @code{MDROTLI @var{a},#@var{b},@var{c}} +@item @code{void __MDSUBACCS (acc, acc)} +@tab @code{__MDSUBACCS (@var{b}, @var{a})} +@tab @code{MDSUBACCS @var{a},@var{b}} +@item @code{void __MDUNPACKH (uw1 *, uw2)} +@tab @code{__MDUNPACKH (&@var{b}, @var{a})} +@tab @code{MDUNPACKH @var{a},@var{b}} +@item @code{uw2 __MEXPDHD (uw1, const)} +@tab @code{@var{c} = __MEXPDHD (@var{a}, @var{b})} +@tab @code{MEXPDHD @var{a},#@var{b},@var{c}} +@item @code{uw1 __MEXPDHW (uw1, const)} +@tab @code{@var{c} = __MEXPDHW (@var{a}, @var{b})} +@tab @code{MEXPDHW @var{a},#@var{b},@var{c}} +@item @code{uw1 __MHDSETH (uw1, const)} +@tab @code{@var{c} = __MHDSETH (@var{a}, @var{b})} +@tab @code{MHDSETH @var{a},#@var{b},@var{c}} +@item @code{sw1 __MHDSETS (const)} +@tab @code{@var{b} = __MHDSETS (@var{a})} +@tab @code{MHDSETS #@var{a},@var{b}} +@item @code{uw1 __MHSETHIH (uw1, const)} +@tab @code{@var{b} = __MHSETHIH (@var{b}, @var{a})} +@tab @code{MHSETHIH #@var{a},@var{b}} +@item @code{sw1 __MHSETHIS (sw1, const)} +@tab @code{@var{b} = __MHSETHIS (@var{b}, @var{a})} +@tab @code{MHSETHIS #@var{a},@var{b}} +@item @code{uw1 __MHSETLOH (uw1, const)} +@tab @code{@var{b} = __MHSETLOH (@var{b}, @var{a})} +@tab @code{MHSETLOH #@var{a},@var{b}} +@item @code{sw1 __MHSETLOS (sw1, const)} +@tab @code{@var{b} = __MHSETLOS (@var{b}, @var{a})} +@tab @code{MHSETLOS #@var{a},@var{b}} +@item @code{uw1 __MHTOB (uw2)} +@tab @code{@var{b} = __MHTOB (@var{a})} +@tab @code{MHTOB @var{a},@var{b}} +@item @code{void __MMACHS (acc, sw1, sw1)} +@tab @code{__MMACHS (@var{c}, @var{a}, @var{b})} +@tab @code{MMACHS @var{a},@var{b},@var{c}} +@item @code{void __MMACHU (acc, uw1, uw1)} +@tab @code{__MMACHU (@var{c}, @var{a}, @var{b})} +@tab @code{MMACHU @var{a},@var{b},@var{c}} +@item @code{void __MMRDHS (acc, sw1, sw1)} +@tab @code{__MMRDHS (@var{c}, @var{a}, @var{b})} +@tab @code{MMRDHS @var{a},@var{b},@var{c}} +@item @code{void __MMRDHU (acc, uw1, uw1)} +@tab @code{__MMRDHU (@var{c}, @var{a}, @var{b})} +@tab @code{MMRDHU @var{a},@var{b},@var{c}} +@item @code{void __MMULHS (acc, sw1, sw1)} +@tab @code{__MMULHS (@var{c}, @var{a}, @var{b})} +@tab @code{MMULHS @var{a},@var{b},@var{c}} +@item @code{void __MMULHU (acc, uw1, uw1)} +@tab @code{__MMULHU (@var{c}, @var{a}, @var{b})} +@tab @code{MMULHU @var{a},@var{b},@var{c}} +@item @code{void __MMULXHS (acc, sw1, sw1)} +@tab @code{__MMULXHS (@var{c}, @var{a}, @var{b})} +@tab @code{MMULXHS @var{a},@var{b},@var{c}} +@item @code{void __MMULXHU (acc, uw1, uw1)} +@tab @code{__MMULXHU (@var{c}, @var{a}, @var{b})} +@tab @code{MMULXHU @var{a},@var{b},@var{c}} +@item @code{uw1 __MNOT (uw1)} +@tab @code{@var{b} = __MNOT (@var{a})} +@tab @code{MNOT @var{a},@var{b}} +@item @code{uw1 __MOR (uw1, uw1)} +@tab @code{@var{c} = __MOR (@var{a}, @var{b})} +@tab @code{MOR @var{a},@var{b},@var{c}} +@item @code{uw1 __MPACKH (uh, uh)} +@tab @code{@var{c} = __MPACKH (@var{a}, @var{b})} +@tab @code{MPACKH @var{a},@var{b},@var{c}} +@item @code{sw2 __MQADDHSS (sw2, sw2)} +@tab @code{@var{c} = __MQADDHSS (@var{a}, @var{b})} +@tab @code{MQADDHSS @var{a},@var{b},@var{c}} +@item @code{uw2 __MQADDHUS (uw2, uw2)} +@tab @code{@var{c} = __MQADDHUS (@var{a}, @var{b})} +@tab @code{MQADDHUS @var{a},@var{b},@var{c}} +@item @code{void __MQCPXIS (acc, sw2, sw2)} +@tab @code{__MQCPXIS (@var{c}, @var{a}, @var{b})} +@tab @code{MQCPXIS @var{a},@var{b},@var{c}} +@item @code{void __MQCPXIU (acc, uw2, uw2)} +@tab @code{__MQCPXIU (@var{c}, @var{a}, @var{b})} +@tab @code{MQCPXIU @var{a},@var{b},@var{c}} +@item @code{void __MQCPXRS (acc, sw2, sw2)} +@tab @code{__MQCPXRS (@var{c}, @var{a}, @var{b})} +@tab @code{MQCPXRS @var{a},@var{b},@var{c}} +@item @code{void __MQCPXRU (acc, uw2, uw2)} +@tab @code{__MQCPXRU (@var{c}, @var{a}, @var{b})} +@tab @code{MQCPXRU @var{a},@var{b},@var{c}} +@item @code{sw2 __MQLCLRHS (sw2, sw2)} +@tab @code{@var{c} = __MQLCLRHS (@var{a}, @var{b})} +@tab @code{MQLCLRHS @var{a},@var{b},@var{c}} +@item @code{sw2 __MQLMTHS (sw2, sw2)} +@tab @code{@var{c} = __MQLMTHS (@var{a}, @var{b})} +@tab @code{MQLMTHS @var{a},@var{b},@var{c}} +@item @code{void __MQMACHS (acc, sw2, sw2)} +@tab @code{__MQMACHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQMACHS @var{a},@var{b},@var{c}} +@item @code{void __MQMACHU (acc, uw2, uw2)} +@tab @code{__MQMACHU (@var{c}, @var{a}, @var{b})} +@tab @code{MQMACHU @var{a},@var{b},@var{c}} +@item @code{void __MQMACXHS (acc, sw2, sw2)} +@tab @code{__MQMACXHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQMACXHS @var{a},@var{b},@var{c}} +@item @code{void __MQMULHS (acc, sw2, sw2)} +@tab @code{__MQMULHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQMULHS @var{a},@var{b},@var{c}} +@item @code{void __MQMULHU (acc, uw2, uw2)} +@tab @code{__MQMULHU (@var{c}, @var{a}, @var{b})} +@tab @code{MQMULHU @var{a},@var{b},@var{c}} +@item @code{void __MQMULXHS (acc, sw2, sw2)} +@tab @code{__MQMULXHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQMULXHS @var{a},@var{b},@var{c}} +@item @code{void __MQMULXHU (acc, uw2, uw2)} +@tab @code{__MQMULXHU (@var{c}, @var{a}, @var{b})} +@tab @code{MQMULXHU @var{a},@var{b},@var{c}} +@item @code{sw2 __MQSATHS (sw2, sw2)} +@tab @code{@var{c} = __MQSATHS (@var{a}, @var{b})} +@tab @code{MQSATHS @var{a},@var{b},@var{c}} +@item @code{uw2 __MQSLLHI (uw2, int)} +@tab @code{@var{c} = __MQSLLHI (@var{a}, @var{b})} +@tab @code{MQSLLHI @var{a},@var{b},@var{c}} +@item @code{sw2 __MQSRAHI (sw2, int)} +@tab @code{@var{c} = __MQSRAHI (@var{a}, @var{b})} +@tab @code{MQSRAHI @var{a},@var{b},@var{c}} +@item @code{sw2 __MQSUBHSS (sw2, sw2)} +@tab @code{@var{c} = __MQSUBHSS (@var{a}, @var{b})} +@tab @code{MQSUBHSS @var{a},@var{b},@var{c}} +@item @code{uw2 __MQSUBHUS (uw2, uw2)} +@tab @code{@var{c} = __MQSUBHUS (@var{a}, @var{b})} +@tab @code{MQSUBHUS @var{a},@var{b},@var{c}} +@item @code{void __MQXMACHS (acc, sw2, sw2)} +@tab @code{__MQXMACHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQXMACHS @var{a},@var{b},@var{c}} +@item @code{void __MQXMACXHS (acc, sw2, sw2)} +@tab @code{__MQXMACXHS (@var{c}, @var{a}, @var{b})} +@tab @code{MQXMACXHS @var{a},@var{b},@var{c}} +@item @code{uw1 __MRDACC (acc)} +@tab @code{@var{b} = __MRDACC (@var{a})} +@tab @code{MRDACC @var{a},@var{b}} +@item @code{uw1 __MRDACCG (acc)} +@tab @code{@var{b} = __MRDACCG (@var{a})} +@tab @code{MRDACCG @var{a},@var{b}} +@item @code{uw1 __MROTLI (uw1, const)} +@tab @code{@var{c} = __MROTLI (@var{a}, @var{b})} +@tab @code{MROTLI @var{a},#@var{b},@var{c}} +@item @code{uw1 __MROTRI (uw1, const)} +@tab @code{@var{c} = __MROTRI (@var{a}, @var{b})} +@tab @code{MROTRI @var{a},#@var{b},@var{c}} +@item @code{sw1 __MSATHS (sw1, sw1)} +@tab @code{@var{c} = __MSATHS (@var{a}, @var{b})} +@tab @code{MSATHS @var{a},@var{b},@var{c}} +@item @code{uw1 __MSATHU (uw1, uw1)} +@tab @code{@var{c} = __MSATHU (@var{a}, @var{b})} +@tab @code{MSATHU @var{a},@var{b},@var{c}} +@item @code{uw1 __MSLLHI (uw1, const)} +@tab @code{@var{c} = __MSLLHI (@var{a}, @var{b})} +@tab @code{MSLLHI @var{a},#@var{b},@var{c}} +@item @code{sw1 __MSRAHI (sw1, const)} +@tab @code{@var{c} = __MSRAHI (@var{a}, @var{b})} +@tab @code{MSRAHI @var{a},#@var{b},@var{c}} +@item @code{uw1 __MSRLHI (uw1, const)} +@tab @code{@var{c} = __MSRLHI (@var{a}, @var{b})} +@tab @code{MSRLHI @var{a},#@var{b},@var{c}} +@item @code{void __MSUBACCS (acc, acc)} +@tab @code{__MSUBACCS (@var{b}, @var{a})} +@tab @code{MSUBACCS @var{a},@var{b}} +@item @code{sw1 __MSUBHSS (sw1, sw1)} +@tab @code{@var{c} = __MSUBHSS (@var{a}, @var{b})} +@tab @code{MSUBHSS @var{a},@var{b},@var{c}} +@item @code{uw1 __MSUBHUS (uw1, uw1)} +@tab @code{@var{c} = __MSUBHUS (@var{a}, @var{b})} +@tab @code{MSUBHUS @var{a},@var{b},@var{c}} +@item @code{void __MTRAP (void)} +@tab @code{__MTRAP ()} +@tab @code{MTRAP} +@item @code{uw2 __MUNPACKH (uw1)} +@tab @code{@var{b} = __MUNPACKH (@var{a})} +@tab @code{MUNPACKH @var{a},@var{b}} +@item @code{uw1 __MWCUT (uw2, uw1)} +@tab @code{@var{c} = __MWCUT (@var{a}, @var{b})} +@tab @code{MWCUT @var{a},@var{b},@var{c}} +@item @code{void __MWTACC (acc, uw1)} +@tab @code{__MWTACC (@var{b}, @var{a})} +@tab @code{MWTACC @var{a},@var{b}} +@item @code{void __MWTACCG (acc, uw1)} +@tab @code{__MWTACCG (@var{b}, @var{a})} +@tab @code{MWTACCG @var{a},@var{b}} +@item @code{uw1 __MXOR (uw1, uw1)} +@tab @code{@var{c} = __MXOR (@var{a}, @var{b})} +@tab @code{MXOR @var{a},@var{b},@var{c}} +@end multitable + +@node Raw read/write Functions +@subsubsection Raw read/write Functions + +This sections describes built-in functions related to read and write +instructions to access memory. These functions generate +@code{membar} instructions to flush the I/O load and stores where +appropriate, as described in Fujitsu's manual described above. + +@table @code + +@item unsigned char __builtin_read8 (void *@var{data}) +@item unsigned short __builtin_read16 (void *@var{data}) +@item unsigned long __builtin_read32 (void *@var{data}) +@item unsigned long long __builtin_read64 (void *@var{data}) + +@item void __builtin_write8 (void *@var{data}, unsigned char @var{datum}) +@item void __builtin_write16 (void *@var{data}, unsigned short @var{datum}) +@item void __builtin_write32 (void *@var{data}, unsigned long @var{datum}) +@item void __builtin_write64 (void *@var{data}, unsigned long long @var{datum}) +@end table + +@node Other Built-in Functions +@subsubsection Other Built-in Functions + +This section describes built-in functions that are not named after +a specific FR-V instruction. + +@table @code +@item sw2 __IACCreadll (iacc @var{reg}) +Return the full 64-bit value of IACC0@. The @var{reg} argument is reserved +for future expansion and must be 0. + +@item sw1 __IACCreadl (iacc @var{reg}) +Return the value of IACC0H if @var{reg} is 0 and IACC0L if @var{reg} is 1. +Other values of @var{reg} are rejected as invalid. + +@item void __IACCsetll (iacc @var{reg}, sw2 @var{x}) +Set the full 64-bit value of IACC0 to @var{x}. The @var{reg} argument +is reserved for future expansion and must be 0. + +@item void __IACCsetl (iacc @var{reg}, sw1 @var{x}) +Set IACC0H to @var{x} if @var{reg} is 0 and IACC0L to @var{x} if @var{reg} +is 1. Other values of @var{reg} are rejected as invalid. + +@item void __data_prefetch0 (const void *@var{x}) +Use the @code{dcpl} instruction to load the contents of address @var{x} +into the data cache. + +@item void __data_prefetch (const void *@var{x}) +Use the @code{nldub} instruction to load the contents of address @var{x} +into the data cache. The instruction will be issued in slot I1@. +@end table + +@node X86 Built-in Functions +@subsection X86 Built-in Functions + +These built-in functions are available for the i386 and x86-64 family +of computers, depending on the command-line switches used. + +Note that, if you specify command-line switches such as @option{-msse}, +the compiler could use the extended instruction sets even if the built-ins +are not used explicitly in the program. For this reason, applications +which perform runtime CPU detection must compile separate files for each +supported architecture, using the appropriate flags. In particular, +the file containing the CPU detection code should be compiled without +these options. + +The following machine modes are available for use with MMX built-in functions +(@pxref{Vector Extensions}): @code{V2SI} for a vector of two 32-bit integers, +@code{V4HI} for a vector of four 16-bit integers, and @code{V8QI} for a +vector of eight 8-bit integers. Some of the built-in functions operate on +@c APPLE LOCAL begin 4656532 use V1DI for _m64 +MMX registers as a whole 64-bit entity, these use @code{V1DI} as their mode. + +If 3Dnow extensions are enabled, @code{V2SF} is used as a mode for a vector +of two 32-bit floating point values. + +If SSE extensions are enabled, @code{V4SF} is used for a vector of four 32-bit +floating point values. Some instructions use a vector of four 32-bit +integers, these use @code{V4SI}. Finally, some instructions operate on an +entire vector register, interpreting it as a 128-bit integer, these use mode +@code{TI}. + +The following built-in functions are made available by @option{-mmmx}. +All of them generate the machine instruction that is part of the name. + +@smallexample +v8qi __builtin_ia32_paddb (v8qi, v8qi) +v4hi __builtin_ia32_paddw (v4hi, v4hi) +v2si __builtin_ia32_paddd (v2si, v2si) +@c APPLE LOCAL begin radar 4395773 +v1di __builtin_ia32_paddq (v1di, v1di) +@c APPLE LOCAL end radar 4395773 +v8qi __builtin_ia32_psubb (v8qi, v8qi) +v4hi __builtin_ia32_psubw (v4hi, v4hi) +v2si __builtin_ia32_psubd (v2si, v2si) +@c APPLE LOCAL begin radar 4395773 +v1di __builtin_ia32_psubq (v1di, v1di) +@c APPLE LOCAL end radar 4395773 +v8qi __builtin_ia32_paddsb (v8qi, v8qi) +v4hi __builtin_ia32_paddsw (v4hi, v4hi) +v8qi __builtin_ia32_psubsb (v8qi, v8qi) +v4hi __builtin_ia32_psubsw (v4hi, v4hi) +v8qi __builtin_ia32_paddusb (v8qi, v8qi) +v4hi __builtin_ia32_paddusw (v4hi, v4hi) +v8qi __builtin_ia32_psubusb (v8qi, v8qi) +v4hi __builtin_ia32_psubusw (v4hi, v4hi) +v4hi __builtin_ia32_pmullw (v4hi, v4hi) +v4hi __builtin_ia32_pmulhw (v4hi, v4hi) +v1di __builtin_ia32_pand (v1di, v1di) +v1di __builtin_ia32_pandn (v1di,v1di) +v1di __builtin_ia32_por (v1di, v1di) +v1di __builtin_ia32_pxor (v1di, v1di) +v8qi __builtin_ia32_pcmpeqb (v8qi, v8qi) +v4hi __builtin_ia32_pcmpeqw (v4hi, v4hi) +v2si __builtin_ia32_pcmpeqd (v2si, v2si) +v8qi __builtin_ia32_pcmpgtb (v8qi, v8qi) +v4hi __builtin_ia32_pcmpgtw (v4hi, v4hi) +v2si __builtin_ia32_pcmpgtd (v2si, v2si) +v8qi __builtin_ia32_punpckhbw (v8qi, v8qi) +v4hi __builtin_ia32_punpckhwd (v4hi, v4hi) +v2si __builtin_ia32_punpckhdq (v2si, v2si) +v8qi __builtin_ia32_punpcklbw (v8qi, v8qi) +v4hi __builtin_ia32_punpcklwd (v4hi, v4hi) +v2si __builtin_ia32_punpckldq (v2si, v2si) +v8qi __builtin_ia32_packsswb (v4hi, v4hi) +v4hi __builtin_ia32_packssdw (v2si, v2si) +v8qi __builtin_ia32_packuswb (v4hi, v4hi) +@c APPLE LOCAL begin radar 4395773 +void __builtin_ia32_emms (void) +v4hi __builtin_ia32_psllw (v4hi, v1di) +v4hi __builtin_ia32_psllwi (v4hi, int) +v2si __builtin_ia32_pslld (v2si, v1di) +v2si __builtin_ia32_pslldi (v2si, int) +v1di __builtin_ia32_psllq (v1di, v1di) +@c APPLE LOCAL radar 4684674 +v1di __builtin_ia32_psllqi (v1di, int) +v4hi __builtin_ia32_psrlw (v4hi, v1di) +v4hi __builtin_ia32_psrlwi (v4hi, int) +v2si __builtin_ia32_psrld (v2si, v1di) +v2si __builtin_ia32_psrldi (v2si, int) +v1di __builtin_ia32_psrlq (v1di, v1di) +@c APPLE LOCAL radar 4684674 +v1di __builtin_ia32_psrlqi (v1di, int) +v4hi __builtin_ia32_psraw (v4hi, v1di) +v4hi __builtin_ia32_psrawi (v4hi, int) +v2si __builtin_ia32_psrad (v2si, v1di) +v2si __builtin_ia32_psradi (v2si, int) +v4hi __builtin_ia32_pshufw (v4hi, int) +v2si __builtin_ia32_pmaddwd (v4hi, v4hi) +v2si __builtin_ia32_vec_init_v2si (int, int) +v4hi __builtin_ia32_vec_init_v4hi (short, short, short, short) +v8qi __builtin_ia32_vec_init_v8qi (char, char, char, char, char, char, char, char) +int __builtin_ia32_vec_ext_v2si (v2si, int) +@c APPLE LOCAL end radar 4395773 +@end smallexample + +The following built-in functions are made available either with +@option{-msse}, or with a combination of @option{-m3dnow} and +@option{-march=athlon}. All of them generate the machine +instruction that is part of the name. + +@smallexample +v4hi __builtin_ia32_pmulhuw (v4hi, v4hi) +v8qi __builtin_ia32_pavgb (v8qi, v8qi) +v4hi __builtin_ia32_pavgw (v4hi, v4hi) +v4hi __builtin_ia32_psadbw (v8qi, v8qi) +v8qi __builtin_ia32_pmaxub (v8qi, v8qi) +v4hi __builtin_ia32_pmaxsw (v4hi, v4hi) +v8qi __builtin_ia32_pminub (v8qi, v8qi) +v4hi __builtin_ia32_pminsw (v4hi, v4hi) +int __builtin_ia32_pextrw (v4hi, int) +v4hi __builtin_ia32_pinsrw (v4hi, int, int) +int __builtin_ia32_pmovmskb (v8qi) +void __builtin_ia32_maskmovq (v8qi, v8qi, char *) +void __builtin_ia32_movntq (v1di *, v1di) +void __builtin_ia32_sfence (void) +@c APPLE LOCAL begin radar 4395773 +int __builtin_ia32_vec_ext_v4hi (v4hi, int) +v4hi __builtin_ia32_vec_set_v4hi (v4hi, int, int) +@c APPLE LOCAL end radar 4395773 +@end smallexample + +The following built-in functions are available when @option{-msse} is used. +All of them generate the machine instruction that is part of the name. + +@smallexample +int __builtin_ia32_comieq (v4sf, v4sf) +int __builtin_ia32_comineq (v4sf, v4sf) +int __builtin_ia32_comilt (v4sf, v4sf) +int __builtin_ia32_comile (v4sf, v4sf) +int __builtin_ia32_comigt (v4sf, v4sf) +int __builtin_ia32_comige (v4sf, v4sf) +int __builtin_ia32_ucomieq (v4sf, v4sf) +int __builtin_ia32_ucomineq (v4sf, v4sf) +int __builtin_ia32_ucomilt (v4sf, v4sf) +int __builtin_ia32_ucomile (v4sf, v4sf) +int __builtin_ia32_ucomigt (v4sf, v4sf) +int __builtin_ia32_ucomige (v4sf, v4sf) +v4sf __builtin_ia32_addps (v4sf, v4sf) +v4sf __builtin_ia32_subps (v4sf, v4sf) +v4sf __builtin_ia32_mulps (v4sf, v4sf) +v4sf __builtin_ia32_divps (v4sf, v4sf) +v4sf __builtin_ia32_addss (v4sf, v4sf) +v4sf __builtin_ia32_subss (v4sf, v4sf) +v4sf __builtin_ia32_mulss (v4sf, v4sf) +v4sf __builtin_ia32_divss (v4sf, v4sf) +v4si __builtin_ia32_cmpeqps (v4sf, v4sf) +v4si __builtin_ia32_cmpltps (v4sf, v4sf) +v4si __builtin_ia32_cmpleps (v4sf, v4sf) +v4si __builtin_ia32_cmpgtps (v4sf, v4sf) +v4si __builtin_ia32_cmpgeps (v4sf, v4sf) +v4si __builtin_ia32_cmpunordps (v4sf, v4sf) +v4si __builtin_ia32_cmpneqps (v4sf, v4sf) +v4si __builtin_ia32_cmpnltps (v4sf, v4sf) +v4si __builtin_ia32_cmpnleps (v4sf, v4sf) +v4si __builtin_ia32_cmpngtps (v4sf, v4sf) +v4si __builtin_ia32_cmpngeps (v4sf, v4sf) +v4si __builtin_ia32_cmpordps (v4sf, v4sf) +v4si __builtin_ia32_cmpeqss (v4sf, v4sf) +v4si __builtin_ia32_cmpltss (v4sf, v4sf) +v4si __builtin_ia32_cmpless (v4sf, v4sf) +v4si __builtin_ia32_cmpunordss (v4sf, v4sf) +v4si __builtin_ia32_cmpneqss (v4sf, v4sf) +v4si __builtin_ia32_cmpnlts (v4sf, v4sf) +v4si __builtin_ia32_cmpnless (v4sf, v4sf) +v4si __builtin_ia32_cmpordss (v4sf, v4sf) +v4sf __builtin_ia32_maxps (v4sf, v4sf) +v4sf __builtin_ia32_maxss (v4sf, v4sf) +v4sf __builtin_ia32_minps (v4sf, v4sf) +v4sf __builtin_ia32_minss (v4sf, v4sf) +v4sf __builtin_ia32_andps (v4sf, v4sf) +v4sf __builtin_ia32_andnps (v4sf, v4sf) +v4sf __builtin_ia32_orps (v4sf, v4sf) +v4sf __builtin_ia32_xorps (v4sf, v4sf) +v4sf __builtin_ia32_movss (v4sf, v4sf) +v4sf __builtin_ia32_movhlps (v4sf, v4sf) +v4sf __builtin_ia32_movlhps (v4sf, v4sf) +v4sf __builtin_ia32_unpckhps (v4sf, v4sf) +v4sf __builtin_ia32_unpcklps (v4sf, v4sf) +v4sf __builtin_ia32_cvtpi2ps (v4sf, v2si) +v4sf __builtin_ia32_cvtsi2ss (v4sf, int) +v2si __builtin_ia32_cvtps2pi (v4sf) +int __builtin_ia32_cvtss2si (v4sf) +v2si __builtin_ia32_cvttps2pi (v4sf) +int __builtin_ia32_cvttss2si (v4sf) +v4sf __builtin_ia32_rcpps (v4sf) +v4sf __builtin_ia32_rsqrtps (v4sf) +v4sf __builtin_ia32_sqrtps (v4sf) +v4sf __builtin_ia32_rcpss (v4sf) +v4sf __builtin_ia32_rsqrtss (v4sf) +v4sf __builtin_ia32_sqrtss (v4sf) +v4sf __builtin_ia32_shufps (v4sf, v4sf, int) +void __builtin_ia32_movntps (float *, v4sf) +int __builtin_ia32_movmskps (v4sf) +@c APPLE LOCAL begin radar 4395773 +void __builtin_ia32_ldmxcsr (unsigned) +unsigned __builtin_ia32_stmxcsr (void) +v2df __builtin_ia32_vec_ext_v2df (v2df, int) +v2di __builtin_ia32_vec_ext_v2di (v2di, int) +v4sf __builtin_ia32_vec_ext_v4sf (v4sf, int) +v4si __builtin_ia32_vec_ext_v4si (v4si, int) +v8hi __builtin_ia32_vec_set_v8hi (v8hi, int, int) +unsigned int __builtin_ia32_vec_ext_v8hi (v8hi, int) +@c APPLE LOCAL end radar 4395773 +@end smallexample + +The following built-in functions are available when @option{-msse} is used. + +@table @code +@item v4sf __builtin_ia32_loadaps (float *) +Generates the @code{movaps} machine instruction as a load from memory. +@item void __builtin_ia32_storeaps (float *, v4sf) +Generates the @code{movaps} machine instruction as a store to memory. +@item v4sf __builtin_ia32_loadups (float *) +Generates the @code{movups} machine instruction as a load from memory. +@item void __builtin_ia32_storeups (float *, v4sf) +Generates the @code{movups} machine instruction as a store to memory. +@item v4sf __builtin_ia32_loadsss (float *) +Generates the @code{movss} machine instruction as a load from memory. +@item void __builtin_ia32_storess (float *, v4sf) +Generates the @code{movss} machine instruction as a store to memory. +@item v4sf __builtin_ia32_loadhps (v4sf, v2si *) +Generates the @code{movhps} machine instruction as a load from memory. +@item v4sf __builtin_ia32_loadlps (v4sf, v2si *) +Generates the @code{movlps} machine instruction as a load from memory +@item void __builtin_ia32_storehps (v4sf, v2si *) +Generates the @code{movhps} machine instruction as a store to memory. +@item void __builtin_ia32_storelps (v4sf, v2si *) +Generates the @code{movlps} machine instruction as a store to memory. +@end table + +The following built-in functions are available when @option{-msse2} is used. +All of them generate the machine instruction that is part of the name. + +@smallexample +int __builtin_ia32_comisdeq (v2df, v2df) +int __builtin_ia32_comisdlt (v2df, v2df) +int __builtin_ia32_comisdle (v2df, v2df) +int __builtin_ia32_comisdgt (v2df, v2df) +int __builtin_ia32_comisdge (v2df, v2df) +int __builtin_ia32_comisdneq (v2df, v2df) +int __builtin_ia32_ucomisdeq (v2df, v2df) +int __builtin_ia32_ucomisdlt (v2df, v2df) +int __builtin_ia32_ucomisdle (v2df, v2df) +int __builtin_ia32_ucomisdgt (v2df, v2df) +int __builtin_ia32_ucomisdge (v2df, v2df) +int __builtin_ia32_ucomisdneq (v2df, v2df) +v2df __builtin_ia32_cmpeqpd (v2df, v2df) +v2df __builtin_ia32_cmpltpd (v2df, v2df) +v2df __builtin_ia32_cmplepd (v2df, v2df) +v2df __builtin_ia32_cmpgtpd (v2df, v2df) +v2df __builtin_ia32_cmpgepd (v2df, v2df) +v2df __builtin_ia32_cmpunordpd (v2df, v2df) +v2df __builtin_ia32_cmpneqpd (v2df, v2df) +v2df __builtin_ia32_cmpnltpd (v2df, v2df) +v2df __builtin_ia32_cmpnlepd (v2df, v2df) +v2df __builtin_ia32_cmpngtpd (v2df, v2df) +v2df __builtin_ia32_cmpngepd (v2df, v2df) +v2df __builtin_ia32_cmpordpd (v2df, v2df) +v2df __builtin_ia32_cmpeqsd (v2df, v2df) +v2df __builtin_ia32_cmpltsd (v2df, v2df) +v2df __builtin_ia32_cmplesd (v2df, v2df) +v2df __builtin_ia32_cmpunordsd (v2df, v2df) +v2df __builtin_ia32_cmpneqsd (v2df, v2df) +v2df __builtin_ia32_cmpnltsd (v2df, v2df) +v2df __builtin_ia32_cmpnlesd (v2df, v2df) +v2df __builtin_ia32_cmpordsd (v2df, v2df) +v2di __builtin_ia32_paddq (v2di, v2di) +v2di __builtin_ia32_psubq (v2di, v2di) +v2df __builtin_ia32_addpd (v2df, v2df) +v2df __builtin_ia32_subpd (v2df, v2df) +v2df __builtin_ia32_mulpd (v2df, v2df) +v2df __builtin_ia32_divpd (v2df, v2df) +v2df __builtin_ia32_addsd (v2df, v2df) +v2df __builtin_ia32_subsd (v2df, v2df) +v2df __builtin_ia32_mulsd (v2df, v2df) +v2df __builtin_ia32_divsd (v2df, v2df) +v2df __builtin_ia32_minpd (v2df, v2df) +v2df __builtin_ia32_maxpd (v2df, v2df) +v2df __builtin_ia32_minsd (v2df, v2df) +v2df __builtin_ia32_maxsd (v2df, v2df) +v2df __builtin_ia32_andpd (v2df, v2df) +v2df __builtin_ia32_andnpd (v2df, v2df) +v2df __builtin_ia32_orpd (v2df, v2df) +v2df __builtin_ia32_xorpd (v2df, v2df) +v2df __builtin_ia32_movsd (v2df, v2df) +v2df __builtin_ia32_unpckhpd (v2df, v2df) +v2df __builtin_ia32_unpcklpd (v2df, v2df) +v16qi __builtin_ia32_paddb128 (v16qi, v16qi) +v8hi __builtin_ia32_paddw128 (v8hi, v8hi) +v4si __builtin_ia32_paddd128 (v4si, v4si) +v2di __builtin_ia32_paddq128 (v2di, v2di) +v16qi __builtin_ia32_psubb128 (v16qi, v16qi) +v8hi __builtin_ia32_psubw128 (v8hi, v8hi) +v4si __builtin_ia32_psubd128 (v4si, v4si) +v2di __builtin_ia32_psubq128 (v2di, v2di) +v8hi __builtin_ia32_pmullw128 (v8hi, v8hi) +v8hi __builtin_ia32_pmulhw128 (v8hi, v8hi) +v2di __builtin_ia32_pand128 (v2di, v2di) +v2di __builtin_ia32_pandn128 (v2di, v2di) +v2di __builtin_ia32_por128 (v2di, v2di) +v2di __builtin_ia32_pxor128 (v2di, v2di) +v16qi __builtin_ia32_pavgb128 (v16qi, v16qi) +v8hi __builtin_ia32_pavgw128 (v8hi, v8hi) +v16qi __builtin_ia32_pcmpeqb128 (v16qi, v16qi) +v8hi __builtin_ia32_pcmpeqw128 (v8hi, v8hi) +v4si __builtin_ia32_pcmpeqd128 (v4si, v4si) +v16qi __builtin_ia32_pcmpgtb128 (v16qi, v16qi) +v8hi __builtin_ia32_pcmpgtw128 (v8hi, v8hi) +v4si __builtin_ia32_pcmpgtd128 (v4si, v4si) +v16qi __builtin_ia32_pmaxub128 (v16qi, v16qi) +v8hi __builtin_ia32_pmaxsw128 (v8hi, v8hi) +v16qi __builtin_ia32_pminub128 (v16qi, v16qi) +v8hi __builtin_ia32_pminsw128 (v8hi, v8hi) +v16qi __builtin_ia32_punpckhbw128 (v16qi, v16qi) +v8hi __builtin_ia32_punpckhwd128 (v8hi, v8hi) +v4si __builtin_ia32_punpckhdq128 (v4si, v4si) +v2di __builtin_ia32_punpckhqdq128 (v2di, v2di) +v16qi __builtin_ia32_punpcklbw128 (v16qi, v16qi) +v8hi __builtin_ia32_punpcklwd128 (v8hi, v8hi) +v4si __builtin_ia32_punpckldq128 (v4si, v4si) +v2di __builtin_ia32_punpcklqdq128 (v2di, v2di) +v16qi __builtin_ia32_packsswb128 (v16qi, v16qi) +v8hi __builtin_ia32_packssdw128 (v8hi, v8hi) +v16qi __builtin_ia32_packuswb128 (v16qi, v16qi) +v8hi __builtin_ia32_pmulhuw128 (v8hi, v8hi) +void __builtin_ia32_maskmovdqu (v16qi, v16qi) +v2df __builtin_ia32_loadupd (double *) +void __builtin_ia32_storeupd (double *, v2df) +v2df __builtin_ia32_loadhpd (v2df, double *) +v2df __builtin_ia32_loadlpd (v2df, double *) +int __builtin_ia32_movmskpd (v2df) +int __builtin_ia32_pmovmskb128 (v16qi) +void __builtin_ia32_movnti (int *, int) +void __builtin_ia32_movntpd (double *, v2df) +void __builtin_ia32_movntdq (v2df *, v2df) +v4si __builtin_ia32_pshufd (v4si, int) +v8hi __builtin_ia32_pshuflw (v8hi, int) +v8hi __builtin_ia32_pshufhw (v8hi, int) +v2di __builtin_ia32_psadbw128 (v16qi, v16qi) +v2df __builtin_ia32_sqrtpd (v2df) +v2df __builtin_ia32_sqrtsd (v2df) +v2df __builtin_ia32_shufpd (v2df, v2df, int) +v2df __builtin_ia32_cvtdq2pd (v4si) +v4sf __builtin_ia32_cvtdq2ps (v4si) +v4si __builtin_ia32_cvtpd2dq (v2df) +v2si __builtin_ia32_cvtpd2pi (v2df) +v4sf __builtin_ia32_cvtpd2ps (v2df) +v4si __builtin_ia32_cvttpd2dq (v2df) +v2si __builtin_ia32_cvttpd2pi (v2df) +v2df __builtin_ia32_cvtpi2pd (v2si) +int __builtin_ia32_cvtsd2si (v2df) +int __builtin_ia32_cvttsd2si (v2df) +long long __builtin_ia32_cvtsd2si64 (v2df) +long long __builtin_ia32_cvttsd2si64 (v2df) +v4si __builtin_ia32_cvtps2dq (v4sf) +v2df __builtin_ia32_cvtps2pd (v4sf) +v4si __builtin_ia32_cvttps2dq (v4sf) +v2df __builtin_ia32_cvtsi2sd (v2df, int) +v2df __builtin_ia32_cvtsi642sd (v2df, long long) +v4sf __builtin_ia32_cvtsd2ss (v4sf, v2df) +v2df __builtin_ia32_cvtss2sd (v2df, v4sf) +void __builtin_ia32_clflush (const void *) +void __builtin_ia32_lfence (void) +void __builtin_ia32_mfence (void) +v16qi __builtin_ia32_loaddqu (const char *) +void __builtin_ia32_storedqu (char *, v16qi) +unsigned long long __builtin_ia32_pmuludq (v2si, v2si) +v2di __builtin_ia32_pmuludq128 (v4si, v4si) +v8hi __builtin_ia32_psllw128 (v8hi, v2di) +v4si __builtin_ia32_pslld128 (v4si, v2di) +v2di __builtin_ia32_psllq128 (v4si, v2di) +v8hi __builtin_ia32_psrlw128 (v8hi, v2di) +v4si __builtin_ia32_psrld128 (v4si, v2di) +v2di __builtin_ia32_psrlq128 (v2di, v2di) +v8hi __builtin_ia32_psraw128 (v8hi, v2di) +v4si __builtin_ia32_psrad128 (v4si, v2di) +v2di __builtin_ia32_pslldqi128 (v2di, int) +v8hi __builtin_ia32_psllwi128 (v8hi, int) +v4si __builtin_ia32_pslldi128 (v4si, int) +v2di __builtin_ia32_psllqi128 (v2di, int) +v2di __builtin_ia32_psrldqi128 (v2di, int) +v8hi __builtin_ia32_psrlwi128 (v8hi, int) +v4si __builtin_ia32_psrldi128 (v4si, int) +v2di __builtin_ia32_psrlqi128 (v2di, int) +v8hi __builtin_ia32_psrawi128 (v8hi, int) +v4si __builtin_ia32_psradi128 (v4si, int) +v4si __builtin_ia32_pmaddwd128 (v8hi, v8hi) +@end smallexample + +The following built-in functions are available when @option{-msse3} is used. +All of them generate the machine instruction that is part of the name. + +@smallexample +v2df __builtin_ia32_addsubpd (v2df, v2df) +v4sf __builtin_ia32_addsubps (v4sf, v4sf) +v2df __builtin_ia32_haddpd (v2df, v2df) +v4sf __builtin_ia32_haddps (v4sf, v4sf) +v2df __builtin_ia32_hsubpd (v2df, v2df) +v4sf __builtin_ia32_hsubps (v4sf, v4sf) +v16qi __builtin_ia32_lddqu (char const *) +void __builtin_ia32_monitor (void *, unsigned int, unsigned int) +v2df __builtin_ia32_movddup (v2df) +v4sf __builtin_ia32_movshdup (v4sf) +v4sf __builtin_ia32_movsldup (v4sf) +void __builtin_ia32_mwait (unsigned int, unsigned int) +@end smallexample + +The following built-in functions are available when @option{-msse3} is used. + +@table @code +@item v2df __builtin_ia32_loadddup (double const *) +Generates the @code{movddup} machine instruction as a load from memory. +@end table + +@c APPLE LOCAL begin mainline +The following built-in functions are available when @option{-mssse3} is used. +All of them generate the machine instruction that is part of the name +with MMX registers. + +@smallexample +v2si __builtin_ia32_phaddd (v2si, v2si) +v4hi __builtin_ia32_phaddw (v4hi, v4hi) +v4hi __builtin_ia32_phaddsw (v4hi, v4hi) +v2si __builtin_ia32_phsubd (v2si, v2si) +v4hi __builtin_ia32_phsubw (v4hi, v4hi) +v4hi __builtin_ia32_phsubsw (v4hi, v4hi) +v8qi __builtin_ia32_pmaddubsw (v8qi, v8qi) +v4hi __builtin_ia32_pmulhrsw (v4hi, v4hi) +v8qi __builtin_ia32_pshufb (v8qi, v8qi) +v8qi __builtin_ia32_psignb (v8qi, v8qi) +v2si __builtin_ia32_psignd (v2si, v2si) +v4hi __builtin_ia32_psignw (v4hi, v4hi) +v1di __builtin_ia32_palignr (v1di, v1di, int) +v8qi __builtin_ia32_pabsb (v8qi) +v2si __builtin_ia32_pabsd (v2si) +v4hi __builtin_ia32_pabsw (v4hi) +@end smallexample +@c APPLE LOCAL end 4656532 use V1DI for _m64 + +The following built-in functions are available when @option{-mssse3} is used. +All of them generate the machine instruction that is part of the name +with SSE registers. + +@smallexample +v4si __builtin_ia32_phaddd128 (v4si, v4si) +v8hi __builtin_ia32_phaddw128 (v8hi, v8hi) +v8hi __builtin_ia32_phaddsw128 (v8hi, v8hi) +v4si __builtin_ia32_phsubd128 (v4si, v4si) +v8hi __builtin_ia32_phsubw128 (v8hi, v8hi) +v8hi __builtin_ia32_phsubsw128 (v8hi, v8hi) +v16qi __builtin_ia32_pmaddubsw128 (v16qi, v16qi) +v8hi __builtin_ia32_pmulhrsw128 (v8hi, v8hi) +v16qi __builtin_ia32_pshufb128 (v16qi, v16qi) +v16qi __builtin_ia32_psignb128 (v16qi, v16qi) +v4si __builtin_ia32_psignd128 (v4si, v4si) +v8hi __builtin_ia32_psignw128 (v8hi, v8hi) +v2di __builtin_ia32_palignr (v2di, v2di, int) +v16qi __builtin_ia32_pabsb128 (v16qi) +v4si __builtin_ia32_pabsd128 (v4si) +v8hi __builtin_ia32_pabsw128 (v8hi) +@end smallexample +@c APPLE LOCAL end mainline +The following built-in functions are available when @option{-m3dnow} is used. +All of them generate the machine instruction that is part of the name. + +@smallexample +void __builtin_ia32_femms (void) +v8qi __builtin_ia32_pavgusb (v8qi, v8qi) +v2si __builtin_ia32_pf2id (v2sf) +v2sf __builtin_ia32_pfacc (v2sf, v2sf) +v2sf __builtin_ia32_pfadd (v2sf, v2sf) +v2si __builtin_ia32_pfcmpeq (v2sf, v2sf) +v2si __builtin_ia32_pfcmpge (v2sf, v2sf) +v2si __builtin_ia32_pfcmpgt (v2sf, v2sf) +v2sf __builtin_ia32_pfmax (v2sf, v2sf) +v2sf __builtin_ia32_pfmin (v2sf, v2sf) +v2sf __builtin_ia32_pfmul (v2sf, v2sf) +v2sf __builtin_ia32_pfrcp (v2sf) +v2sf __builtin_ia32_pfrcpit1 (v2sf, v2sf) +v2sf __builtin_ia32_pfrcpit2 (v2sf, v2sf) +v2sf __builtin_ia32_pfrsqrt (v2sf) +v2sf __builtin_ia32_pfrsqrtit1 (v2sf, v2sf) +v2sf __builtin_ia32_pfsub (v2sf, v2sf) +v2sf __builtin_ia32_pfsubr (v2sf, v2sf) +v2sf __builtin_ia32_pi2fd (v2si) +v4hi __builtin_ia32_pmulhrw (v4hi, v4hi) +@end smallexample + +The following built-in functions are available when both @option{-m3dnow} +and @option{-march=athlon} are used. All of them generate the machine +instruction that is part of the name. + +@smallexample +v2si __builtin_ia32_pf2iw (v2sf) +v2sf __builtin_ia32_pfnacc (v2sf, v2sf) +v2sf __builtin_ia32_pfpnacc (v2sf, v2sf) +v2sf __builtin_ia32_pi2fw (v2si) +v2sf __builtin_ia32_pswapdsf (v2sf) +v2si __builtin_ia32_pswapdsi (v2si) +@end smallexample + +@node MIPS DSP Built-in Functions +@subsection MIPS DSP Built-in Functions + +The MIPS DSP Application-Specific Extension (ASE) includes new +instructions that are designed to improve the performance of DSP and +media applications. It provides instructions that operate on packed +8-bit integer data, Q15 fractional data and Q31 fractional data. + +GCC supports MIPS DSP operations using both the generic +vector extensions (@pxref{Vector Extensions}) and a collection of +MIPS-specific built-in functions. Both kinds of support are +enabled by the @option{-mdsp} command-line option. + +At present, GCC only provides support for operations on 32-bit +vectors. The vector type associated with 8-bit integer data is +usually called @code{v4i8} and the vector type associated with Q15 is +usually called @code{v2q15}. They can be defined in C as follows: + +@smallexample +typedef char v4i8 __attribute__ ((vector_size(4))); +typedef short v2q15 __attribute__ ((vector_size(4))); +@end smallexample + +@code{v4i8} and @code{v2q15} values are initialized in the same way as +aggregates. For example: + +@smallexample +v4i8 a = @{1, 2, 3, 4@}; +v4i8 b; +b = (v4i8) @{5, 6, 7, 8@}; + +v2q15 c = @{0x0fcb, 0x3a75@}; +v2q15 d; +d = (v2q15) @{0.1234 * 0x1.0p15, 0.4567 * 0x1.0p15@}; +@end smallexample + +@emph{Note:} The CPU's endianness determines the order in which values +are packed. On little-endian targets, the first value is the least +significant and the last value is the most significant. The opposite +order applies to big-endian targets. For example, the code above will +set the lowest byte of @code{a} to @code{1} on little-endian targets +and @code{4} on big-endian targets. + +@emph{Note:} Q15 and Q31 values must be initialized with their integer +representation. As shown in this example, the integer representation +of a Q15 value can be obtained by multiplying the fractional value by +@code{0x1.0p15}. The equivalent for Q31 values is to multiply by +@code{0x1.0p31}. + +The table below lists the @code{v4i8} and @code{v2q15} operations for which +hardware support exists. @code{a} and @code{b} are @code{v4i8} values, +and @code{c} and @code{d} are @code{v2q15} values. + +@multitable @columnfractions .50 .50 +@item C code @tab MIPS instruction +@item @code{a + b} @tab @code{addu.qb} +@item @code{c + d} @tab @code{addq.ph} +@item @code{a - b} @tab @code{subu.qb} +@item @code{c - d} @tab @code{subq.ph} +@end multitable + +It is easier to describe the DSP built-in functions if we first define +the following types: + +@smallexample +typedef int q31; +typedef int i32; +typedef long long a64; +@end smallexample + +@code{q31} and @code{i32} are actually the same as @code{int}, but we +use @code{q31} to indicate a Q31 fractional value and @code{i32} to +indicate a 32-bit integer value. Similarly, @code{a64} is the same as +@code{long long}, but we use @code{a64} to indicate values that will +be placed in one of the four DSP accumulators (@code{$ac0}, +@code{$ac1}, @code{$ac2} or @code{$ac3}). + +Also, some built-in functions prefer or require immediate numbers as +parameters, because the corresponding DSP instructions accept both immediate +numbers and register operands, or accept immediate numbers only. The +immediate parameters are listed as follows. + +@smallexample +imm0_7: 0 to 7. +imm0_15: 0 to 15. +imm0_31: 0 to 31. +imm0_63: 0 to 63. +imm0_255: 0 to 255. +imm_n32_31: -32 to 31. +imm_n512_511: -512 to 511. +@end smallexample + +The following built-in functions map directly to a particular MIPS DSP +instruction. Please refer to the architecture specification +for details on what each instruction does. + +@smallexample +v2q15 __builtin_mips_addq_ph (v2q15, v2q15) +v2q15 __builtin_mips_addq_s_ph (v2q15, v2q15) +q31 __builtin_mips_addq_s_w (q31, q31) +v4i8 __builtin_mips_addu_qb (v4i8, v4i8) +v4i8 __builtin_mips_addu_s_qb (v4i8, v4i8) +v2q15 __builtin_mips_subq_ph (v2q15, v2q15) +v2q15 __builtin_mips_subq_s_ph (v2q15, v2q15) +q31 __builtin_mips_subq_s_w (q31, q31) +v4i8 __builtin_mips_subu_qb (v4i8, v4i8) +v4i8 __builtin_mips_subu_s_qb (v4i8, v4i8) +i32 __builtin_mips_addsc (i32, i32) +i32 __builtin_mips_addwc (i32, i32) +i32 __builtin_mips_modsub (i32, i32) +i32 __builtin_mips_raddu_w_qb (v4i8) +v2q15 __builtin_mips_absq_s_ph (v2q15) +q31 __builtin_mips_absq_s_w (q31) +v4i8 __builtin_mips_precrq_qb_ph (v2q15, v2q15) +v2q15 __builtin_mips_precrq_ph_w (q31, q31) +v2q15 __builtin_mips_precrq_rs_ph_w (q31, q31) +v4i8 __builtin_mips_precrqu_s_qb_ph (v2q15, v2q15) +q31 __builtin_mips_preceq_w_phl (v2q15) +q31 __builtin_mips_preceq_w_phr (v2q15) +v2q15 __builtin_mips_precequ_ph_qbl (v4i8) +v2q15 __builtin_mips_precequ_ph_qbr (v4i8) +v2q15 __builtin_mips_precequ_ph_qbla (v4i8) +v2q15 __builtin_mips_precequ_ph_qbra (v4i8) +v2q15 __builtin_mips_preceu_ph_qbl (v4i8) +v2q15 __builtin_mips_preceu_ph_qbr (v4i8) +v2q15 __builtin_mips_preceu_ph_qbla (v4i8) +v2q15 __builtin_mips_preceu_ph_qbra (v4i8) +v4i8 __builtin_mips_shll_qb (v4i8, imm0_7) +v4i8 __builtin_mips_shll_qb (v4i8, i32) +v2q15 __builtin_mips_shll_ph (v2q15, imm0_15) +v2q15 __builtin_mips_shll_ph (v2q15, i32) +v2q15 __builtin_mips_shll_s_ph (v2q15, imm0_15) +v2q15 __builtin_mips_shll_s_ph (v2q15, i32) +q31 __builtin_mips_shll_s_w (q31, imm0_31) +q31 __builtin_mips_shll_s_w (q31, i32) +v4i8 __builtin_mips_shrl_qb (v4i8, imm0_7) +v4i8 __builtin_mips_shrl_qb (v4i8, i32) +v2q15 __builtin_mips_shra_ph (v2q15, imm0_15) +v2q15 __builtin_mips_shra_ph (v2q15, i32) +v2q15 __builtin_mips_shra_r_ph (v2q15, imm0_15) +v2q15 __builtin_mips_shra_r_ph (v2q15, i32) +q31 __builtin_mips_shra_r_w (q31, imm0_31) +q31 __builtin_mips_shra_r_w (q31, i32) +v2q15 __builtin_mips_muleu_s_ph_qbl (v4i8, v2q15) +v2q15 __builtin_mips_muleu_s_ph_qbr (v4i8, v2q15) +v2q15 __builtin_mips_mulq_rs_ph (v2q15, v2q15) +q31 __builtin_mips_muleq_s_w_phl (v2q15, v2q15) +q31 __builtin_mips_muleq_s_w_phr (v2q15, v2q15) +a64 __builtin_mips_dpau_h_qbl (a64, v4i8, v4i8) +a64 __builtin_mips_dpau_h_qbr (a64, v4i8, v4i8) +a64 __builtin_mips_dpsu_h_qbl (a64, v4i8, v4i8) +a64 __builtin_mips_dpsu_h_qbr (a64, v4i8, v4i8) +a64 __builtin_mips_dpaq_s_w_ph (a64, v2q15, v2q15) +a64 __builtin_mips_dpaq_sa_l_w (a64, q31, q31) +a64 __builtin_mips_dpsq_s_w_ph (a64, v2q15, v2q15) +a64 __builtin_mips_dpsq_sa_l_w (a64, q31, q31) +a64 __builtin_mips_mulsaq_s_w_ph (a64, v2q15, v2q15) +a64 __builtin_mips_maq_s_w_phl (a64, v2q15, v2q15) +a64 __builtin_mips_maq_s_w_phr (a64, v2q15, v2q15) +a64 __builtin_mips_maq_sa_w_phl (a64, v2q15, v2q15) +a64 __builtin_mips_maq_sa_w_phr (a64, v2q15, v2q15) +i32 __builtin_mips_bitrev (i32) +i32 __builtin_mips_insv (i32, i32) +v4i8 __builtin_mips_repl_qb (imm0_255) +v4i8 __builtin_mips_repl_qb (i32) +v2q15 __builtin_mips_repl_ph (imm_n512_511) +v2q15 __builtin_mips_repl_ph (i32) +void __builtin_mips_cmpu_eq_qb (v4i8, v4i8) +void __builtin_mips_cmpu_lt_qb (v4i8, v4i8) +void __builtin_mips_cmpu_le_qb (v4i8, v4i8) +i32 __builtin_mips_cmpgu_eq_qb (v4i8, v4i8) +i32 __builtin_mips_cmpgu_lt_qb (v4i8, v4i8) +i32 __builtin_mips_cmpgu_le_qb (v4i8, v4i8) +void __builtin_mips_cmp_eq_ph (v2q15, v2q15) +void __builtin_mips_cmp_lt_ph (v2q15, v2q15) +void __builtin_mips_cmp_le_ph (v2q15, v2q15) +v4i8 __builtin_mips_pick_qb (v4i8, v4i8) +v2q15 __builtin_mips_pick_ph (v2q15, v2q15) +v2q15 __builtin_mips_packrl_ph (v2q15, v2q15) +i32 __builtin_mips_extr_w (a64, imm0_31) +i32 __builtin_mips_extr_w (a64, i32) +i32 __builtin_mips_extr_r_w (a64, imm0_31) +i32 __builtin_mips_extr_s_h (a64, i32) +i32 __builtin_mips_extr_rs_w (a64, imm0_31) +i32 __builtin_mips_extr_rs_w (a64, i32) +i32 __builtin_mips_extr_s_h (a64, imm0_31) +i32 __builtin_mips_extr_r_w (a64, i32) +i32 __builtin_mips_extp (a64, imm0_31) +i32 __builtin_mips_extp (a64, i32) +i32 __builtin_mips_extpdp (a64, imm0_31) +i32 __builtin_mips_extpdp (a64, i32) +a64 __builtin_mips_shilo (a64, imm_n32_31) +a64 __builtin_mips_shilo (a64, i32) +a64 __builtin_mips_mthlip (a64, i32) +void __builtin_mips_wrdsp (i32, imm0_63) +i32 __builtin_mips_rddsp (imm0_63) +i32 __builtin_mips_lbux (void *, i32) +i32 __builtin_mips_lhx (void *, i32) +i32 __builtin_mips_lwx (void *, i32) +i32 __builtin_mips_bposge32 (void) +@end smallexample + +@node MIPS Paired-Single Support +@subsection MIPS Paired-Single Support + +The MIPS64 architecture includes a number of instructions that +operate on pairs of single-precision floating-point values. +Each pair is packed into a 64-bit floating-point register, +with one element being designated the ``upper half'' and +the other being designated the ``lower half''. + +GCC supports paired-single operations using both the generic +vector extensions (@pxref{Vector Extensions}) and a collection of +MIPS-specific built-in functions. Both kinds of support are +enabled by the @option{-mpaired-single} command-line option. + +The vector type associated with paired-single values is usually +called @code{v2sf}. It can be defined in C as follows: + +@smallexample +typedef float v2sf __attribute__ ((vector_size (8))); +@end smallexample + +@code{v2sf} values are initialized in the same way as aggregates. +For example: + +@smallexample +v2sf a = @{1.5, 9.1@}; +v2sf b; +float e, f; +b = (v2sf) @{e, f@}; +@end smallexample + +@emph{Note:} The CPU's endianness determines which value is stored in +the upper half of a register and which value is stored in the lower half. +On little-endian targets, the first value is the lower one and the second +value is the upper one. The opposite order applies to big-endian targets. +For example, the code above will set the lower half of @code{a} to +@code{1.5} on little-endian targets and @code{9.1} on big-endian targets. + +@menu +* Paired-Single Arithmetic:: +* Paired-Single Built-in Functions:: +* MIPS-3D Built-in Functions:: +@end menu + +@node Paired-Single Arithmetic +@subsubsection Paired-Single Arithmetic + +The table below lists the @code{v2sf} operations for which hardware +support exists. @code{a}, @code{b} and @code{c} are @code{v2sf} +values and @code{x} is an integral value. + +@multitable @columnfractions .50 .50 +@item C code @tab MIPS instruction +@item @code{a + b} @tab @code{add.ps} +@item @code{a - b} @tab @code{sub.ps} +@item @code{-a} @tab @code{neg.ps} +@item @code{a * b} @tab @code{mul.ps} +@item @code{a * b + c} @tab @code{madd.ps} +@item @code{a * b - c} @tab @code{msub.ps} +@item @code{-(a * b + c)} @tab @code{nmadd.ps} +@item @code{-(a * b - c)} @tab @code{nmsub.ps} +@item @code{x ? a : b} @tab @code{movn.ps}/@code{movz.ps} +@end multitable + +Note that the multiply-accumulate instructions can be disabled +using the command-line option @code{-mno-fused-madd}. + +@node Paired-Single Built-in Functions +@subsubsection Paired-Single Built-in Functions + +The following paired-single functions map directly to a particular +MIPS instruction. Please refer to the architecture specification +for details on what each instruction does. + +@table @code +@item v2sf __builtin_mips_pll_ps (v2sf, v2sf) +Pair lower lower (@code{pll.ps}). + +@item v2sf __builtin_mips_pul_ps (v2sf, v2sf) +Pair upper lower (@code{pul.ps}). + +@item v2sf __builtin_mips_plu_ps (v2sf, v2sf) +Pair lower upper (@code{plu.ps}). + +@item v2sf __builtin_mips_puu_ps (v2sf, v2sf) +Pair upper upper (@code{puu.ps}). + +@item v2sf __builtin_mips_cvt_ps_s (float, float) +Convert pair to paired single (@code{cvt.ps.s}). + +@item float __builtin_mips_cvt_s_pl (v2sf) +Convert pair lower to single (@code{cvt.s.pl}). + +@item float __builtin_mips_cvt_s_pu (v2sf) +Convert pair upper to single (@code{cvt.s.pu}). + +@item v2sf __builtin_mips_abs_ps (v2sf) +Absolute value (@code{abs.ps}). + +@item v2sf __builtin_mips_alnv_ps (v2sf, v2sf, int) +Align variable (@code{alnv.ps}). + +@emph{Note:} The value of the third parameter must be 0 or 4 +modulo 8, otherwise the result will be unpredictable. Please read the +instruction description for details. +@end table + +The following multi-instruction functions are also available. +In each case, @var{cond} can be any of the 16 floating-point conditions: +@code{f}, @code{un}, @code{eq}, @code{ueq}, @code{olt}, @code{ult}, +@code{ole}, @code{ule}, @code{sf}, @code{ngle}, @code{seq}, @code{ngl}, +@code{lt}, @code{nge}, @code{le} or @code{ngt}. + +@table @code +@item v2sf __builtin_mips_movt_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +@itemx v2sf __builtin_mips_movf_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +Conditional move based on floating point comparison (@code{c.@var{cond}.ps}, +@code{movt.ps}/@code{movf.ps}). + +The @code{movt} functions return the value @var{x} computed by: + +@smallexample +c.@var{cond}.ps @var{cc},@var{a},@var{b} +mov.ps @var{x},@var{c} +movt.ps @var{x},@var{d},@var{cc} +@end smallexample + +The @code{movf} functions are similar but use @code{movf.ps} instead +of @code{movt.ps}. + +@item int __builtin_mips_upper_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +@itemx int __builtin_mips_lower_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +Comparison of two paired-single values (@code{c.@var{cond}.ps}, +@code{bc1t}/@code{bc1f}). + +These functions compare @var{a} and @var{b} using @code{c.@var{cond}.ps} +and return either the upper or lower half of the result. For example: + +@smallexample +v2sf a, b; +if (__builtin_mips_upper_c_eq_ps (a, b)) + upper_halves_are_equal (); +else + upper_halves_are_unequal (); + +if (__builtin_mips_lower_c_eq_ps (a, b)) + lower_halves_are_equal (); +else + lower_halves_are_unequal (); +@end smallexample +@end table + +@node MIPS-3D Built-in Functions +@subsubsection MIPS-3D Built-in Functions + +The MIPS-3D Application-Specific Extension (ASE) includes additional +paired-single instructions that are designed to improve the performance +of 3D graphics operations. Support for these instructions is controlled +by the @option{-mips3d} command-line option. + +The functions listed below map directly to a particular MIPS-3D +instruction. Please refer to the architecture specification for +more details on what each instruction does. + +@table @code +@item v2sf __builtin_mips_addr_ps (v2sf, v2sf) +Reduction add (@code{addr.ps}). + +@item v2sf __builtin_mips_mulr_ps (v2sf, v2sf) +Reduction multiply (@code{mulr.ps}). + +@item v2sf __builtin_mips_cvt_pw_ps (v2sf) +Convert paired single to paired word (@code{cvt.pw.ps}). + +@item v2sf __builtin_mips_cvt_ps_pw (v2sf) +Convert paired word to paired single (@code{cvt.ps.pw}). + +@item float __builtin_mips_recip1_s (float) +@itemx double __builtin_mips_recip1_d (double) +@itemx v2sf __builtin_mips_recip1_ps (v2sf) +Reduced precision reciprocal (sequence step 1) (@code{recip1.@var{fmt}}). + +@item float __builtin_mips_recip2_s (float, float) +@itemx double __builtin_mips_recip2_d (double, double) +@itemx v2sf __builtin_mips_recip2_ps (v2sf, v2sf) +Reduced precision reciprocal (sequence step 2) (@code{recip2.@var{fmt}}). + +@item float __builtin_mips_rsqrt1_s (float) +@itemx double __builtin_mips_rsqrt1_d (double) +@itemx v2sf __builtin_mips_rsqrt1_ps (v2sf) +Reduced precision reciprocal square root (sequence step 1) +(@code{rsqrt1.@var{fmt}}). + +@item float __builtin_mips_rsqrt2_s (float, float) +@itemx double __builtin_mips_rsqrt2_d (double, double) +@itemx v2sf __builtin_mips_rsqrt2_ps (v2sf, v2sf) +Reduced precision reciprocal square root (sequence step 2) +(@code{rsqrt2.@var{fmt}}). +@end table + +The following multi-instruction functions are also available. +In each case, @var{cond} can be any of the 16 floating-point conditions: +@code{f}, @code{un}, @code{eq}, @code{ueq}, @code{olt}, @code{ult}, +@code{ole}, @code{ule}, @code{sf}, @code{ngle}, @code{seq}, +@code{ngl}, @code{lt}, @code{nge}, @code{le} or @code{ngt}. + +@table @code +@item int __builtin_mips_cabs_@var{cond}_s (float @var{a}, float @var{b}) +@itemx int __builtin_mips_cabs_@var{cond}_d (double @var{a}, double @var{b}) +Absolute comparison of two scalar values (@code{cabs.@var{cond}.@var{fmt}}, +@code{bc1t}/@code{bc1f}). + +These functions compare @var{a} and @var{b} using @code{cabs.@var{cond}.s} +or @code{cabs.@var{cond}.d} and return the result as a boolean value. +For example: + +@smallexample +float a, b; +if (__builtin_mips_cabs_eq_s (a, b)) + true (); +else + false (); +@end smallexample + +@item int __builtin_mips_upper_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +@itemx int __builtin_mips_lower_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +Absolute comparison of two paired-single values (@code{cabs.@var{cond}.ps}, +@code{bc1t}/@code{bc1f}). + +These functions compare @var{a} and @var{b} using @code{cabs.@var{cond}.ps} +and return either the upper or lower half of the result. For example: + +@smallexample +v2sf a, b; +if (__builtin_mips_upper_cabs_eq_ps (a, b)) + upper_halves_are_equal (); +else + upper_halves_are_unequal (); + +if (__builtin_mips_lower_cabs_eq_ps (a, b)) + lower_halves_are_equal (); +else + lower_halves_are_unequal (); +@end smallexample + +@item v2sf __builtin_mips_movt_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +@itemx v2sf __builtin_mips_movf_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +Conditional move based on absolute comparison (@code{cabs.@var{cond}.ps}, +@code{movt.ps}/@code{movf.ps}). + +The @code{movt} functions return the value @var{x} computed by: + +@smallexample +cabs.@var{cond}.ps @var{cc},@var{a},@var{b} +mov.ps @var{x},@var{c} +movt.ps @var{x},@var{d},@var{cc} +@end smallexample + +The @code{movf} functions are similar but use @code{movf.ps} instead +of @code{movt.ps}. + +@item int __builtin_mips_any_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +@itemx int __builtin_mips_all_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +@itemx int __builtin_mips_any_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +@itemx int __builtin_mips_all_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) +Comparison of two paired-single values +(@code{c.@var{cond}.ps}/@code{cabs.@var{cond}.ps}, +@code{bc1any2t}/@code{bc1any2f}). + +These functions compare @var{a} and @var{b} using @code{c.@var{cond}.ps} +or @code{cabs.@var{cond}.ps}. The @code{any} forms return true if either +result is true and the @code{all} forms return true if both results are true. +For example: + +@smallexample +v2sf a, b; +if (__builtin_mips_any_c_eq_ps (a, b)) + one_is_true (); +else + both_are_false (); + +if (__builtin_mips_all_c_eq_ps (a, b)) + both_are_true (); +else + one_is_false (); +@end smallexample + +@item int __builtin_mips_any_c_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +@itemx int __builtin_mips_all_c_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +@itemx int __builtin_mips_any_cabs_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +@itemx int __builtin_mips_all_cabs_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) +Comparison of four paired-single values +(@code{c.@var{cond}.ps}/@code{cabs.@var{cond}.ps}, +@code{bc1any4t}/@code{bc1any4f}). + +These functions use @code{c.@var{cond}.ps} or @code{cabs.@var{cond}.ps} +to compare @var{a} with @var{b} and to compare @var{c} with @var{d}. +The @code{any} forms return true if any of the four results are true +and the @code{all} forms return true if all four results are true. +For example: + +@smallexample +v2sf a, b, c, d; +if (__builtin_mips_any_c_eq_4s (a, b, c, d)) + some_are_true (); +else + all_are_false (); + +if (__builtin_mips_all_c_eq_4s (a, b, c, d)) + all_are_true (); +else + some_are_false (); +@end smallexample +@end table + +@node PowerPC AltiVec Built-in Functions +@subsection PowerPC AltiVec Built-in Functions + +GCC provides an interface for the PowerPC family of processors to access +the AltiVec operations described in Motorola's AltiVec Programming +Interface Manual. The interface is made available by including +@code{<altivec.h>} and using @option{-maltivec} and +@option{-mabi=altivec}. The interface supports the following vector +types. + +@smallexample +vector unsigned char +vector signed char +vector bool char + +vector unsigned short +vector signed short +vector bool short +vector pixel + +vector unsigned int +vector signed int +vector bool int +vector float +@end smallexample + +GCC's implementation of the high-level language interface available from +C and C++ code differs from Motorola's documentation in several ways. + +@itemize @bullet + +@item +A vector constant is a list of constant expressions within curly braces. + +@item +A vector initializer requires no cast if the vector constant is of the +same type as the variable it is initializing. + +@item +If @code{signed} or @code{unsigned} is omitted, the signedness of the +vector type is the default signedness of the base type. The default +varies depending on the operating system, so a portable program should +always specify the signedness. + +@item +Compiling with @option{-maltivec} adds keywords @code{__vector}, +@code{__pixel}, and @code{__bool}. Macros @option{vector}, +@code{pixel}, and @code{bool} are defined in @code{<altivec.h>} and can +be undefined. + +@item +GCC allows using a @code{typedef} name as the type specifier for a +vector type. + +@item +For C, overloaded functions are implemented with macros so the following +does not work: + +@smallexample + vec_add ((vector signed int)@{1, 2, 3, 4@}, foo); +@end smallexample + +Since @code{vec_add} is a macro, the vector constant in the example +is treated as four separate arguments. Wrap the entire argument in +parentheses for this to work. +@end itemize + +@emph{Note:} Only the @code{<altivec.h>} interface is supported. +Internally, GCC uses built-in functions to achieve the functionality in +the aforementioned header file, but they are not supported and are +subject to change without notice. + +The following interfaces are supported for the generic and specific +AltiVec operations and the AltiVec predicates. In cases where there +is a direct mapping between generic and specific operations, only the +generic names are shown here, although the specific operations can also +be used. + +Arguments that are documented as @code{const int} require literal +integral values within the range required for that operation. + +@smallexample +vector signed char vec_abs (vector signed char); +vector signed short vec_abs (vector signed short); +vector signed int vec_abs (vector signed int); +vector float vec_abs (vector float); + +vector signed char vec_abss (vector signed char); +vector signed short vec_abss (vector signed short); +vector signed int vec_abss (vector signed int); + +vector signed char vec_add (vector bool char, vector signed char); +vector signed char vec_add (vector signed char, vector bool char); +vector signed char vec_add (vector signed char, vector signed char); +vector unsigned char vec_add (vector bool char, vector unsigned char); +vector unsigned char vec_add (vector unsigned char, vector bool char); +vector unsigned char vec_add (vector unsigned char, + vector unsigned char); +vector signed short vec_add (vector bool short, vector signed short); +vector signed short vec_add (vector signed short, vector bool short); +vector signed short vec_add (vector signed short, vector signed short); +vector unsigned short vec_add (vector bool short, + vector unsigned short); +vector unsigned short vec_add (vector unsigned short, + vector bool short); +vector unsigned short vec_add (vector unsigned short, + vector unsigned short); +vector signed int vec_add (vector bool int, vector signed int); +vector signed int vec_add (vector signed int, vector bool int); +vector signed int vec_add (vector signed int, vector signed int); +vector unsigned int vec_add (vector bool int, vector unsigned int); +vector unsigned int vec_add (vector unsigned int, vector bool int); +vector unsigned int vec_add (vector unsigned int, vector unsigned int); +vector float vec_add (vector float, vector float); + +vector float vec_vaddfp (vector float, vector float); + +vector signed int vec_vadduwm (vector bool int, vector signed int); +vector signed int vec_vadduwm (vector signed int, vector bool int); +vector signed int vec_vadduwm (vector signed int, vector signed int); +vector unsigned int vec_vadduwm (vector bool int, vector unsigned int); +vector unsigned int vec_vadduwm (vector unsigned int, vector bool int); +vector unsigned int vec_vadduwm (vector unsigned int, + vector unsigned int); + +vector signed short vec_vadduhm (vector bool short, + vector signed short); +vector signed short vec_vadduhm (vector signed short, + vector bool short); +vector signed short vec_vadduhm (vector signed short, + vector signed short); +vector unsigned short vec_vadduhm (vector bool short, + vector unsigned short); +vector unsigned short vec_vadduhm (vector unsigned short, + vector bool short); +vector unsigned short vec_vadduhm (vector unsigned short, + vector unsigned short); + +vector signed char vec_vaddubm (vector bool char, vector signed char); +vector signed char vec_vaddubm (vector signed char, vector bool char); +vector signed char vec_vaddubm (vector signed char, vector signed char); +vector unsigned char vec_vaddubm (vector bool char, + vector unsigned char); +vector unsigned char vec_vaddubm (vector unsigned char, + vector bool char); +vector unsigned char vec_vaddubm (vector unsigned char, + vector unsigned char); + +vector unsigned int vec_addc (vector unsigned int, vector unsigned int); + +vector unsigned char vec_adds (vector bool char, vector unsigned char); +vector unsigned char vec_adds (vector unsigned char, vector bool char); +vector unsigned char vec_adds (vector unsigned char, + vector unsigned char); +vector signed char vec_adds (vector bool char, vector signed char); +vector signed char vec_adds (vector signed char, vector bool char); +vector signed char vec_adds (vector signed char, vector signed char); +vector unsigned short vec_adds (vector bool short, + vector unsigned short); +vector unsigned short vec_adds (vector unsigned short, + vector bool short); +vector unsigned short vec_adds (vector unsigned short, + vector unsigned short); +vector signed short vec_adds (vector bool short, vector signed short); +vector signed short vec_adds (vector signed short, vector bool short); +vector signed short vec_adds (vector signed short, vector signed short); +vector unsigned int vec_adds (vector bool int, vector unsigned int); +vector unsigned int vec_adds (vector unsigned int, vector bool int); +vector unsigned int vec_adds (vector unsigned int, vector unsigned int); +vector signed int vec_adds (vector bool int, vector signed int); +vector signed int vec_adds (vector signed int, vector bool int); +vector signed int vec_adds (vector signed int, vector signed int); + +vector signed int vec_vaddsws (vector bool int, vector signed int); +vector signed int vec_vaddsws (vector signed int, vector bool int); +vector signed int vec_vaddsws (vector signed int, vector signed int); + +vector unsigned int vec_vadduws (vector bool int, vector unsigned int); +vector unsigned int vec_vadduws (vector unsigned int, vector bool int); +vector unsigned int vec_vadduws (vector unsigned int, + vector unsigned int); + +vector signed short vec_vaddshs (vector bool short, + vector signed short); +vector signed short vec_vaddshs (vector signed short, + vector bool short); +vector signed short vec_vaddshs (vector signed short, + vector signed short); + +vector unsigned short vec_vadduhs (vector bool short, + vector unsigned short); +vector unsigned short vec_vadduhs (vector unsigned short, + vector bool short); +vector unsigned short vec_vadduhs (vector unsigned short, + vector unsigned short); + +vector signed char vec_vaddsbs (vector bool char, vector signed char); +vector signed char vec_vaddsbs (vector signed char, vector bool char); +vector signed char vec_vaddsbs (vector signed char, vector signed char); + +vector unsigned char vec_vaddubs (vector bool char, + vector unsigned char); +vector unsigned char vec_vaddubs (vector unsigned char, + vector bool char); +vector unsigned char vec_vaddubs (vector unsigned char, + vector unsigned char); + +vector float vec_and (vector float, vector float); +vector float vec_and (vector float, vector bool int); +vector float vec_and (vector bool int, vector float); +vector bool int vec_and (vector bool int, vector bool int); +vector signed int vec_and (vector bool int, vector signed int); +vector signed int vec_and (vector signed int, vector bool int); +vector signed int vec_and (vector signed int, vector signed int); +vector unsigned int vec_and (vector bool int, vector unsigned int); +vector unsigned int vec_and (vector unsigned int, vector bool int); +vector unsigned int vec_and (vector unsigned int, vector unsigned int); +vector bool short vec_and (vector bool short, vector bool short); +vector signed short vec_and (vector bool short, vector signed short); +vector signed short vec_and (vector signed short, vector bool short); +vector signed short vec_and (vector signed short, vector signed short); +vector unsigned short vec_and (vector bool short, + vector unsigned short); +vector unsigned short vec_and (vector unsigned short, + vector bool short); +vector unsigned short vec_and (vector unsigned short, + vector unsigned short); +vector signed char vec_and (vector bool char, vector signed char); +vector bool char vec_and (vector bool char, vector bool char); +vector signed char vec_and (vector signed char, vector bool char); +vector signed char vec_and (vector signed char, vector signed char); +vector unsigned char vec_and (vector bool char, vector unsigned char); +vector unsigned char vec_and (vector unsigned char, vector bool char); +vector unsigned char vec_and (vector unsigned char, + vector unsigned char); + +vector float vec_andc (vector float, vector float); +vector float vec_andc (vector float, vector bool int); +vector float vec_andc (vector bool int, vector float); +vector bool int vec_andc (vector bool int, vector bool int); +vector signed int vec_andc (vector bool int, vector signed int); +vector signed int vec_andc (vector signed int, vector bool int); +vector signed int vec_andc (vector signed int, vector signed int); +vector unsigned int vec_andc (vector bool int, vector unsigned int); +vector unsigned int vec_andc (vector unsigned int, vector bool int); +vector unsigned int vec_andc (vector unsigned int, vector unsigned int); +vector bool short vec_andc (vector bool short, vector bool short); +vector signed short vec_andc (vector bool short, vector signed short); +vector signed short vec_andc (vector signed short, vector bool short); +vector signed short vec_andc (vector signed short, vector signed short); +vector unsigned short vec_andc (vector bool short, + vector unsigned short); +vector unsigned short vec_andc (vector unsigned short, + vector bool short); +vector unsigned short vec_andc (vector unsigned short, + vector unsigned short); +vector signed char vec_andc (vector bool char, vector signed char); +vector bool char vec_andc (vector bool char, vector bool char); +vector signed char vec_andc (vector signed char, vector bool char); +vector signed char vec_andc (vector signed char, vector signed char); +vector unsigned char vec_andc (vector bool char, vector unsigned char); +vector unsigned char vec_andc (vector unsigned char, vector bool char); +vector unsigned char vec_andc (vector unsigned char, + vector unsigned char); + +vector unsigned char vec_avg (vector unsigned char, + vector unsigned char); +vector signed char vec_avg (vector signed char, vector signed char); +vector unsigned short vec_avg (vector unsigned short, + vector unsigned short); +vector signed short vec_avg (vector signed short, vector signed short); +vector unsigned int vec_avg (vector unsigned int, vector unsigned int); +vector signed int vec_avg (vector signed int, vector signed int); + +vector signed int vec_vavgsw (vector signed int, vector signed int); + +vector unsigned int vec_vavguw (vector unsigned int, + vector unsigned int); + +vector signed short vec_vavgsh (vector signed short, + vector signed short); + +vector unsigned short vec_vavguh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vavgsb (vector signed char, vector signed char); + +vector unsigned char vec_vavgub (vector unsigned char, + vector unsigned char); + +vector float vec_ceil (vector float); + +vector signed int vec_cmpb (vector float, vector float); + +vector bool char vec_cmpeq (vector signed char, vector signed char); +vector bool char vec_cmpeq (vector unsigned char, vector unsigned char); +vector bool short vec_cmpeq (vector signed short, vector signed short); +vector bool short vec_cmpeq (vector unsigned short, + vector unsigned short); +vector bool int vec_cmpeq (vector signed int, vector signed int); +vector bool int vec_cmpeq (vector unsigned int, vector unsigned int); +vector bool int vec_cmpeq (vector float, vector float); + +vector bool int vec_vcmpeqfp (vector float, vector float); + +vector bool int vec_vcmpequw (vector signed int, vector signed int); +vector bool int vec_vcmpequw (vector unsigned int, vector unsigned int); + +vector bool short vec_vcmpequh (vector signed short, + vector signed short); +vector bool short vec_vcmpequh (vector unsigned short, + vector unsigned short); + +vector bool char vec_vcmpequb (vector signed char, vector signed char); +vector bool char vec_vcmpequb (vector unsigned char, + vector unsigned char); + +vector bool int vec_cmpge (vector float, vector float); + +vector bool char vec_cmpgt (vector unsigned char, vector unsigned char); +vector bool char vec_cmpgt (vector signed char, vector signed char); +vector bool short vec_cmpgt (vector unsigned short, + vector unsigned short); +vector bool short vec_cmpgt (vector signed short, vector signed short); +vector bool int vec_cmpgt (vector unsigned int, vector unsigned int); +vector bool int vec_cmpgt (vector signed int, vector signed int); +vector bool int vec_cmpgt (vector float, vector float); + +vector bool int vec_vcmpgtfp (vector float, vector float); + +vector bool int vec_vcmpgtsw (vector signed int, vector signed int); + +vector bool int vec_vcmpgtuw (vector unsigned int, vector unsigned int); + +vector bool short vec_vcmpgtsh (vector signed short, + vector signed short); + +vector bool short vec_vcmpgtuh (vector unsigned short, + vector unsigned short); + +vector bool char vec_vcmpgtsb (vector signed char, vector signed char); + +vector bool char vec_vcmpgtub (vector unsigned char, + vector unsigned char); + +vector bool int vec_cmple (vector float, vector float); + +vector bool char vec_cmplt (vector unsigned char, vector unsigned char); +vector bool char vec_cmplt (vector signed char, vector signed char); +vector bool short vec_cmplt (vector unsigned short, + vector unsigned short); +vector bool short vec_cmplt (vector signed short, vector signed short); +vector bool int vec_cmplt (vector unsigned int, vector unsigned int); +vector bool int vec_cmplt (vector signed int, vector signed int); +vector bool int vec_cmplt (vector float, vector float); + +vector float vec_ctf (vector unsigned int, const int); +vector float vec_ctf (vector signed int, const int); + +vector float vec_vcfsx (vector signed int, const int); + +vector float vec_vcfux (vector unsigned int, const int); + +vector signed int vec_cts (vector float, const int); + +vector unsigned int vec_ctu (vector float, const int); + +void vec_dss (const int); + +void vec_dssall (void); + +void vec_dst (const vector unsigned char *, int, const int); +void vec_dst (const vector signed char *, int, const int); +void vec_dst (const vector bool char *, int, const int); +void vec_dst (const vector unsigned short *, int, const int); +void vec_dst (const vector signed short *, int, const int); +void vec_dst (const vector bool short *, int, const int); +void vec_dst (const vector pixel *, int, const int); +void vec_dst (const vector unsigned int *, int, const int); +void vec_dst (const vector signed int *, int, const int); +void vec_dst (const vector bool int *, int, const int); +void vec_dst (const vector float *, int, const int); +void vec_dst (const unsigned char *, int, const int); +void vec_dst (const signed char *, int, const int); +void vec_dst (const unsigned short *, int, const int); +void vec_dst (const short *, int, const int); +void vec_dst (const unsigned int *, int, const int); +void vec_dst (const int *, int, const int); +void vec_dst (const unsigned long *, int, const int); +void vec_dst (const long *, int, const int); +void vec_dst (const float *, int, const int); + +void vec_dstst (const vector unsigned char *, int, const int); +void vec_dstst (const vector signed char *, int, const int); +void vec_dstst (const vector bool char *, int, const int); +void vec_dstst (const vector unsigned short *, int, const int); +void vec_dstst (const vector signed short *, int, const int); +void vec_dstst (const vector bool short *, int, const int); +void vec_dstst (const vector pixel *, int, const int); +void vec_dstst (const vector unsigned int *, int, const int); +void vec_dstst (const vector signed int *, int, const int); +void vec_dstst (const vector bool int *, int, const int); +void vec_dstst (const vector float *, int, const int); +void vec_dstst (const unsigned char *, int, const int); +void vec_dstst (const signed char *, int, const int); +void vec_dstst (const unsigned short *, int, const int); +void vec_dstst (const short *, int, const int); +void vec_dstst (const unsigned int *, int, const int); +void vec_dstst (const int *, int, const int); +void vec_dstst (const unsigned long *, int, const int); +void vec_dstst (const long *, int, const int); +void vec_dstst (const float *, int, const int); + +void vec_dststt (const vector unsigned char *, int, const int); +void vec_dststt (const vector signed char *, int, const int); +void vec_dststt (const vector bool char *, int, const int); +void vec_dststt (const vector unsigned short *, int, const int); +void vec_dststt (const vector signed short *, int, const int); +void vec_dststt (const vector bool short *, int, const int); +void vec_dststt (const vector pixel *, int, const int); +void vec_dststt (const vector unsigned int *, int, const int); +void vec_dststt (const vector signed int *, int, const int); +void vec_dststt (const vector bool int *, int, const int); +void vec_dststt (const vector float *, int, const int); +void vec_dststt (const unsigned char *, int, const int); +void vec_dststt (const signed char *, int, const int); +void vec_dststt (const unsigned short *, int, const int); +void vec_dststt (const short *, int, const int); +void vec_dststt (const unsigned int *, int, const int); +void vec_dststt (const int *, int, const int); +void vec_dststt (const unsigned long *, int, const int); +void vec_dststt (const long *, int, const int); +void vec_dststt (const float *, int, const int); + +void vec_dstt (const vector unsigned char *, int, const int); +void vec_dstt (const vector signed char *, int, const int); +void vec_dstt (const vector bool char *, int, const int); +void vec_dstt (const vector unsigned short *, int, const int); +void vec_dstt (const vector signed short *, int, const int); +void vec_dstt (const vector bool short *, int, const int); +void vec_dstt (const vector pixel *, int, const int); +void vec_dstt (const vector unsigned int *, int, const int); +void vec_dstt (const vector signed int *, int, const int); +void vec_dstt (const vector bool int *, int, const int); +void vec_dstt (const vector float *, int, const int); +void vec_dstt (const unsigned char *, int, const int); +void vec_dstt (const signed char *, int, const int); +void vec_dstt (const unsigned short *, int, const int); +void vec_dstt (const short *, int, const int); +void vec_dstt (const unsigned int *, int, const int); +void vec_dstt (const int *, int, const int); +void vec_dstt (const unsigned long *, int, const int); +void vec_dstt (const long *, int, const int); +void vec_dstt (const float *, int, const int); + +vector float vec_expte (vector float); + +vector float vec_floor (vector float); + +vector float vec_ld (int, const vector float *); +vector float vec_ld (int, const float *); +vector bool int vec_ld (int, const vector bool int *); +vector signed int vec_ld (int, const vector signed int *); +vector signed int vec_ld (int, const int *); +vector signed int vec_ld (int, const long *); +vector unsigned int vec_ld (int, const vector unsigned int *); +vector unsigned int vec_ld (int, const unsigned int *); +vector unsigned int vec_ld (int, const unsigned long *); +vector bool short vec_ld (int, const vector bool short *); +vector pixel vec_ld (int, const vector pixel *); +vector signed short vec_ld (int, const vector signed short *); +vector signed short vec_ld (int, const short *); +vector unsigned short vec_ld (int, const vector unsigned short *); +vector unsigned short vec_ld (int, const unsigned short *); +vector bool char vec_ld (int, const vector bool char *); +vector signed char vec_ld (int, const vector signed char *); +vector signed char vec_ld (int, const signed char *); +vector unsigned char vec_ld (int, const vector unsigned char *); +vector unsigned char vec_ld (int, const unsigned char *); + +vector signed char vec_lde (int, const signed char *); +vector unsigned char vec_lde (int, const unsigned char *); +vector signed short vec_lde (int, const short *); +vector unsigned short vec_lde (int, const unsigned short *); +vector float vec_lde (int, const float *); +vector signed int vec_lde (int, const int *); +vector unsigned int vec_lde (int, const unsigned int *); +vector signed int vec_lde (int, const long *); +vector unsigned int vec_lde (int, const unsigned long *); + +vector float vec_lvewx (int, float *); +vector signed int vec_lvewx (int, int *); +vector unsigned int vec_lvewx (int, unsigned int *); +vector signed int vec_lvewx (int, long *); +vector unsigned int vec_lvewx (int, unsigned long *); + +vector signed short vec_lvehx (int, short *); +vector unsigned short vec_lvehx (int, unsigned short *); + +vector signed char vec_lvebx (int, char *); +vector unsigned char vec_lvebx (int, unsigned char *); + +vector float vec_ldl (int, const vector float *); +vector float vec_ldl (int, const float *); +vector bool int vec_ldl (int, const vector bool int *); +vector signed int vec_ldl (int, const vector signed int *); +vector signed int vec_ldl (int, const int *); +vector signed int vec_ldl (int, const long *); +vector unsigned int vec_ldl (int, const vector unsigned int *); +vector unsigned int vec_ldl (int, const unsigned int *); +vector unsigned int vec_ldl (int, const unsigned long *); +vector bool short vec_ldl (int, const vector bool short *); +vector pixel vec_ldl (int, const vector pixel *); +vector signed short vec_ldl (int, const vector signed short *); +vector signed short vec_ldl (int, const short *); +vector unsigned short vec_ldl (int, const vector unsigned short *); +vector unsigned short vec_ldl (int, const unsigned short *); +vector bool char vec_ldl (int, const vector bool char *); +vector signed char vec_ldl (int, const vector signed char *); +vector signed char vec_ldl (int, const signed char *); +vector unsigned char vec_ldl (int, const vector unsigned char *); +vector unsigned char vec_ldl (int, const unsigned char *); + +vector float vec_loge (vector float); + +vector unsigned char vec_lvsl (int, const volatile unsigned char *); +vector unsigned char vec_lvsl (int, const volatile signed char *); +vector unsigned char vec_lvsl (int, const volatile unsigned short *); +vector unsigned char vec_lvsl (int, const volatile short *); +vector unsigned char vec_lvsl (int, const volatile unsigned int *); +vector unsigned char vec_lvsl (int, const volatile int *); +vector unsigned char vec_lvsl (int, const volatile unsigned long *); +vector unsigned char vec_lvsl (int, const volatile long *); +vector unsigned char vec_lvsl (int, const volatile float *); + +vector unsigned char vec_lvsr (int, const volatile unsigned char *); +vector unsigned char vec_lvsr (int, const volatile signed char *); +vector unsigned char vec_lvsr (int, const volatile unsigned short *); +vector unsigned char vec_lvsr (int, const volatile short *); +vector unsigned char vec_lvsr (int, const volatile unsigned int *); +vector unsigned char vec_lvsr (int, const volatile int *); +vector unsigned char vec_lvsr (int, const volatile unsigned long *); +vector unsigned char vec_lvsr (int, const volatile long *); +vector unsigned char vec_lvsr (int, const volatile float *); + +vector float vec_madd (vector float, vector float, vector float); + +vector signed short vec_madds (vector signed short, + vector signed short, + vector signed short); + +vector unsigned char vec_max (vector bool char, vector unsigned char); +vector unsigned char vec_max (vector unsigned char, vector bool char); +vector unsigned char vec_max (vector unsigned char, + vector unsigned char); +vector signed char vec_max (vector bool char, vector signed char); +vector signed char vec_max (vector signed char, vector bool char); +vector signed char vec_max (vector signed char, vector signed char); +vector unsigned short vec_max (vector bool short, + vector unsigned short); +vector unsigned short vec_max (vector unsigned short, + vector bool short); +vector unsigned short vec_max (vector unsigned short, + vector unsigned short); +vector signed short vec_max (vector bool short, vector signed short); +vector signed short vec_max (vector signed short, vector bool short); +vector signed short vec_max (vector signed short, vector signed short); +vector unsigned int vec_max (vector bool int, vector unsigned int); +vector unsigned int vec_max (vector unsigned int, vector bool int); +vector unsigned int vec_max (vector unsigned int, vector unsigned int); +vector signed int vec_max (vector bool int, vector signed int); +vector signed int vec_max (vector signed int, vector bool int); +vector signed int vec_max (vector signed int, vector signed int); +vector float vec_max (vector float, vector float); + +vector float vec_vmaxfp (vector float, vector float); + +vector signed int vec_vmaxsw (vector bool int, vector signed int); +vector signed int vec_vmaxsw (vector signed int, vector bool int); +vector signed int vec_vmaxsw (vector signed int, vector signed int); + +vector unsigned int vec_vmaxuw (vector bool int, vector unsigned int); +vector unsigned int vec_vmaxuw (vector unsigned int, vector bool int); +vector unsigned int vec_vmaxuw (vector unsigned int, + vector unsigned int); + +vector signed short vec_vmaxsh (vector bool short, vector signed short); +vector signed short vec_vmaxsh (vector signed short, vector bool short); +vector signed short vec_vmaxsh (vector signed short, + vector signed short); + +vector unsigned short vec_vmaxuh (vector bool short, + vector unsigned short); +vector unsigned short vec_vmaxuh (vector unsigned short, + vector bool short); +vector unsigned short vec_vmaxuh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vmaxsb (vector bool char, vector signed char); +vector signed char vec_vmaxsb (vector signed char, vector bool char); +vector signed char vec_vmaxsb (vector signed char, vector signed char); + +vector unsigned char vec_vmaxub (vector bool char, + vector unsigned char); +vector unsigned char vec_vmaxub (vector unsigned char, + vector bool char); +vector unsigned char vec_vmaxub (vector unsigned char, + vector unsigned char); + +vector bool char vec_mergeh (vector bool char, vector bool char); +vector signed char vec_mergeh (vector signed char, vector signed char); +vector unsigned char vec_mergeh (vector unsigned char, + vector unsigned char); +vector bool short vec_mergeh (vector bool short, vector bool short); +vector pixel vec_mergeh (vector pixel, vector pixel); +vector signed short vec_mergeh (vector signed short, + vector signed short); +vector unsigned short vec_mergeh (vector unsigned short, + vector unsigned short); +vector float vec_mergeh (vector float, vector float); +vector bool int vec_mergeh (vector bool int, vector bool int); +vector signed int vec_mergeh (vector signed int, vector signed int); +vector unsigned int vec_mergeh (vector unsigned int, + vector unsigned int); + +vector float vec_vmrghw (vector float, vector float); +vector bool int vec_vmrghw (vector bool int, vector bool int); +vector signed int vec_vmrghw (vector signed int, vector signed int); +vector unsigned int vec_vmrghw (vector unsigned int, + vector unsigned int); + +vector bool short vec_vmrghh (vector bool short, vector bool short); +vector signed short vec_vmrghh (vector signed short, + vector signed short); +vector unsigned short vec_vmrghh (vector unsigned short, + vector unsigned short); +vector pixel vec_vmrghh (vector pixel, vector pixel); + +vector bool char vec_vmrghb (vector bool char, vector bool char); +vector signed char vec_vmrghb (vector signed char, vector signed char); +vector unsigned char vec_vmrghb (vector unsigned char, + vector unsigned char); + +vector bool char vec_mergel (vector bool char, vector bool char); +vector signed char vec_mergel (vector signed char, vector signed char); +vector unsigned char vec_mergel (vector unsigned char, + vector unsigned char); +vector bool short vec_mergel (vector bool short, vector bool short); +vector pixel vec_mergel (vector pixel, vector pixel); +vector signed short vec_mergel (vector signed short, + vector signed short); +vector unsigned short vec_mergel (vector unsigned short, + vector unsigned short); +vector float vec_mergel (vector float, vector float); +vector bool int vec_mergel (vector bool int, vector bool int); +vector signed int vec_mergel (vector signed int, vector signed int); +vector unsigned int vec_mergel (vector unsigned int, + vector unsigned int); + +vector float vec_vmrglw (vector float, vector float); +vector signed int vec_vmrglw (vector signed int, vector signed int); +vector unsigned int vec_vmrglw (vector unsigned int, + vector unsigned int); +vector bool int vec_vmrglw (vector bool int, vector bool int); + +vector bool short vec_vmrglh (vector bool short, vector bool short); +vector signed short vec_vmrglh (vector signed short, + vector signed short); +vector unsigned short vec_vmrglh (vector unsigned short, + vector unsigned short); +vector pixel vec_vmrglh (vector pixel, vector pixel); + +vector bool char vec_vmrglb (vector bool char, vector bool char); +vector signed char vec_vmrglb (vector signed char, vector signed char); +vector unsigned char vec_vmrglb (vector unsigned char, + vector unsigned char); + +vector unsigned short vec_mfvscr (void); + +vector unsigned char vec_min (vector bool char, vector unsigned char); +vector unsigned char vec_min (vector unsigned char, vector bool char); +vector unsigned char vec_min (vector unsigned char, + vector unsigned char); +vector signed char vec_min (vector bool char, vector signed char); +vector signed char vec_min (vector signed char, vector bool char); +vector signed char vec_min (vector signed char, vector signed char); +vector unsigned short vec_min (vector bool short, + vector unsigned short); +vector unsigned short vec_min (vector unsigned short, + vector bool short); +vector unsigned short vec_min (vector unsigned short, + vector unsigned short); +vector signed short vec_min (vector bool short, vector signed short); +vector signed short vec_min (vector signed short, vector bool short); +vector signed short vec_min (vector signed short, vector signed short); +vector unsigned int vec_min (vector bool int, vector unsigned int); +vector unsigned int vec_min (vector unsigned int, vector bool int); +vector unsigned int vec_min (vector unsigned int, vector unsigned int); +vector signed int vec_min (vector bool int, vector signed int); +vector signed int vec_min (vector signed int, vector bool int); +vector signed int vec_min (vector signed int, vector signed int); +vector float vec_min (vector float, vector float); + +vector float vec_vminfp (vector float, vector float); + +vector signed int vec_vminsw (vector bool int, vector signed int); +vector signed int vec_vminsw (vector signed int, vector bool int); +vector signed int vec_vminsw (vector signed int, vector signed int); + +vector unsigned int vec_vminuw (vector bool int, vector unsigned int); +vector unsigned int vec_vminuw (vector unsigned int, vector bool int); +vector unsigned int vec_vminuw (vector unsigned int, + vector unsigned int); + +vector signed short vec_vminsh (vector bool short, vector signed short); +vector signed short vec_vminsh (vector signed short, vector bool short); +vector signed short vec_vminsh (vector signed short, + vector signed short); + +vector unsigned short vec_vminuh (vector bool short, + vector unsigned short); +vector unsigned short vec_vminuh (vector unsigned short, + vector bool short); +vector unsigned short vec_vminuh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vminsb (vector bool char, vector signed char); +vector signed char vec_vminsb (vector signed char, vector bool char); +vector signed char vec_vminsb (vector signed char, vector signed char); + +vector unsigned char vec_vminub (vector bool char, + vector unsigned char); +vector unsigned char vec_vminub (vector unsigned char, + vector bool char); +vector unsigned char vec_vminub (vector unsigned char, + vector unsigned char); + +vector signed short vec_mladd (vector signed short, + vector signed short, + vector signed short); +vector signed short vec_mladd (vector signed short, + vector unsigned short, + vector unsigned short); +vector signed short vec_mladd (vector unsigned short, + vector signed short, + vector signed short); +vector unsigned short vec_mladd (vector unsigned short, + vector unsigned short, + vector unsigned short); + +vector signed short vec_mradds (vector signed short, + vector signed short, + vector signed short); + +vector unsigned int vec_msum (vector unsigned char, + vector unsigned char, + vector unsigned int); +vector signed int vec_msum (vector signed char, + vector unsigned char, + vector signed int); +vector unsigned int vec_msum (vector unsigned short, + vector unsigned short, + vector unsigned int); +vector signed int vec_msum (vector signed short, + vector signed short, + vector signed int); + +vector signed int vec_vmsumshm (vector signed short, + vector signed short, + vector signed int); + +vector unsigned int vec_vmsumuhm (vector unsigned short, + vector unsigned short, + vector unsigned int); + +vector signed int vec_vmsummbm (vector signed char, + vector unsigned char, + vector signed int); + +vector unsigned int vec_vmsumubm (vector unsigned char, + vector unsigned char, + vector unsigned int); + +vector unsigned int vec_msums (vector unsigned short, + vector unsigned short, + vector unsigned int); +vector signed int vec_msums (vector signed short, + vector signed short, + vector signed int); + +vector signed int vec_vmsumshs (vector signed short, + vector signed short, + vector signed int); + +vector unsigned int vec_vmsumuhs (vector unsigned short, + vector unsigned short, + vector unsigned int); + +void vec_mtvscr (vector signed int); +void vec_mtvscr (vector unsigned int); +void vec_mtvscr (vector bool int); +void vec_mtvscr (vector signed short); +void vec_mtvscr (vector unsigned short); +void vec_mtvscr (vector bool short); +void vec_mtvscr (vector pixel); +void vec_mtvscr (vector signed char); +void vec_mtvscr (vector unsigned char); +void vec_mtvscr (vector bool char); + +vector unsigned short vec_mule (vector unsigned char, + vector unsigned char); +vector signed short vec_mule (vector signed char, + vector signed char); +vector unsigned int vec_mule (vector unsigned short, + vector unsigned short); +vector signed int vec_mule (vector signed short, vector signed short); + +vector signed int vec_vmulesh (vector signed short, + vector signed short); + +vector unsigned int vec_vmuleuh (vector unsigned short, + vector unsigned short); + +vector signed short vec_vmulesb (vector signed char, + vector signed char); + +vector unsigned short vec_vmuleub (vector unsigned char, + vector unsigned char); + +vector unsigned short vec_mulo (vector unsigned char, + vector unsigned char); +vector signed short vec_mulo (vector signed char, vector signed char); +vector unsigned int vec_mulo (vector unsigned short, + vector unsigned short); +vector signed int vec_mulo (vector signed short, vector signed short); + +vector signed int vec_vmulosh (vector signed short, + vector signed short); + +vector unsigned int vec_vmulouh (vector unsigned short, + vector unsigned short); + +vector signed short vec_vmulosb (vector signed char, + vector signed char); + +vector unsigned short vec_vmuloub (vector unsigned char, + vector unsigned char); + +vector float vec_nmsub (vector float, vector float, vector float); +@c APPLE LOCAL begin fixhtml --mrs +@end smallexample + +@smallexample +@c APPLE LOCAL end fixhtml --mrs +vector float vec_nor (vector float, vector float); +vector signed int vec_nor (vector signed int, vector signed int); +vector unsigned int vec_nor (vector unsigned int, vector unsigned int); +vector bool int vec_nor (vector bool int, vector bool int); +vector signed short vec_nor (vector signed short, vector signed short); +vector unsigned short vec_nor (vector unsigned short, + vector unsigned short); +vector bool short vec_nor (vector bool short, vector bool short); +vector signed char vec_nor (vector signed char, vector signed char); +vector unsigned char vec_nor (vector unsigned char, + vector unsigned char); +vector bool char vec_nor (vector bool char, vector bool char); + +vector float vec_or (vector float, vector float); +vector float vec_or (vector float, vector bool int); +vector float vec_or (vector bool int, vector float); +vector bool int vec_or (vector bool int, vector bool int); +vector signed int vec_or (vector bool int, vector signed int); +vector signed int vec_or (vector signed int, vector bool int); +vector signed int vec_or (vector signed int, vector signed int); +vector unsigned int vec_or (vector bool int, vector unsigned int); +vector unsigned int vec_or (vector unsigned int, vector bool int); +vector unsigned int vec_or (vector unsigned int, vector unsigned int); +vector bool short vec_or (vector bool short, vector bool short); +vector signed short vec_or (vector bool short, vector signed short); +vector signed short vec_or (vector signed short, vector bool short); +vector signed short vec_or (vector signed short, vector signed short); +vector unsigned short vec_or (vector bool short, vector unsigned short); +vector unsigned short vec_or (vector unsigned short, vector bool short); +vector unsigned short vec_or (vector unsigned short, + vector unsigned short); +vector signed char vec_or (vector bool char, vector signed char); +vector bool char vec_or (vector bool char, vector bool char); +vector signed char vec_or (vector signed char, vector bool char); +vector signed char vec_or (vector signed char, vector signed char); +vector unsigned char vec_or (vector bool char, vector unsigned char); +vector unsigned char vec_or (vector unsigned char, vector bool char); +vector unsigned char vec_or (vector unsigned char, + vector unsigned char); + +vector signed char vec_pack (vector signed short, vector signed short); +vector unsigned char vec_pack (vector unsigned short, + vector unsigned short); +vector bool char vec_pack (vector bool short, vector bool short); +vector signed short vec_pack (vector signed int, vector signed int); +vector unsigned short vec_pack (vector unsigned int, + vector unsigned int); +vector bool short vec_pack (vector bool int, vector bool int); + +vector bool short vec_vpkuwum (vector bool int, vector bool int); +vector signed short vec_vpkuwum (vector signed int, vector signed int); +vector unsigned short vec_vpkuwum (vector unsigned int, + vector unsigned int); + +vector bool char vec_vpkuhum (vector bool short, vector bool short); +vector signed char vec_vpkuhum (vector signed short, + vector signed short); +vector unsigned char vec_vpkuhum (vector unsigned short, + vector unsigned short); + +vector pixel vec_packpx (vector unsigned int, vector unsigned int); + +vector unsigned char vec_packs (vector unsigned short, + vector unsigned short); +vector signed char vec_packs (vector signed short, vector signed short); +vector unsigned short vec_packs (vector unsigned int, + vector unsigned int); +vector signed short vec_packs (vector signed int, vector signed int); + +vector signed short vec_vpkswss (vector signed int, vector signed int); + +vector unsigned short vec_vpkuwus (vector unsigned int, + vector unsigned int); + +vector signed char vec_vpkshss (vector signed short, + vector signed short); + +vector unsigned char vec_vpkuhus (vector unsigned short, + vector unsigned short); + +vector unsigned char vec_packsu (vector unsigned short, + vector unsigned short); +vector unsigned char vec_packsu (vector signed short, + vector signed short); +vector unsigned short vec_packsu (vector unsigned int, + vector unsigned int); +vector unsigned short vec_packsu (vector signed int, vector signed int); + +vector unsigned short vec_vpkswus (vector signed int, + vector signed int); + +vector unsigned char vec_vpkshus (vector signed short, + vector signed short); + +vector float vec_perm (vector float, + vector float, + vector unsigned char); +vector signed int vec_perm (vector signed int, + vector signed int, + vector unsigned char); +vector unsigned int vec_perm (vector unsigned int, + vector unsigned int, + vector unsigned char); +vector bool int vec_perm (vector bool int, + vector bool int, + vector unsigned char); +vector signed short vec_perm (vector signed short, + vector signed short, + vector unsigned char); +vector unsigned short vec_perm (vector unsigned short, + vector unsigned short, + vector unsigned char); +vector bool short vec_perm (vector bool short, + vector bool short, + vector unsigned char); +vector pixel vec_perm (vector pixel, + vector pixel, + vector unsigned char); +vector signed char vec_perm (vector signed char, + vector signed char, + vector unsigned char); +vector unsigned char vec_perm (vector unsigned char, + vector unsigned char, + vector unsigned char); +vector bool char vec_perm (vector bool char, + vector bool char, + vector unsigned char); + +vector float vec_re (vector float); + +vector signed char vec_rl (vector signed char, + vector unsigned char); +vector unsigned char vec_rl (vector unsigned char, + vector unsigned char); +vector signed short vec_rl (vector signed short, vector unsigned short); +vector unsigned short vec_rl (vector unsigned short, + vector unsigned short); +vector signed int vec_rl (vector signed int, vector unsigned int); +vector unsigned int vec_rl (vector unsigned int, vector unsigned int); + +vector signed int vec_vrlw (vector signed int, vector unsigned int); +vector unsigned int vec_vrlw (vector unsigned int, vector unsigned int); + +vector signed short vec_vrlh (vector signed short, + vector unsigned short); +vector unsigned short vec_vrlh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vrlb (vector signed char, vector unsigned char); +vector unsigned char vec_vrlb (vector unsigned char, + vector unsigned char); + +vector float vec_round (vector float); + +vector float vec_rsqrte (vector float); + +vector float vec_sel (vector float, vector float, vector bool int); +vector float vec_sel (vector float, vector float, vector unsigned int); +vector signed int vec_sel (vector signed int, + vector signed int, + vector bool int); +vector signed int vec_sel (vector signed int, + vector signed int, + vector unsigned int); +vector unsigned int vec_sel (vector unsigned int, + vector unsigned int, + vector bool int); +vector unsigned int vec_sel (vector unsigned int, + vector unsigned int, + vector unsigned int); +vector bool int vec_sel (vector bool int, + vector bool int, + vector bool int); +vector bool int vec_sel (vector bool int, + vector bool int, + vector unsigned int); +vector signed short vec_sel (vector signed short, + vector signed short, + vector bool short); +vector signed short vec_sel (vector signed short, + vector signed short, + vector unsigned short); +vector unsigned short vec_sel (vector unsigned short, + vector unsigned short, + vector bool short); +vector unsigned short vec_sel (vector unsigned short, + vector unsigned short, + vector unsigned short); +vector bool short vec_sel (vector bool short, + vector bool short, + vector bool short); +vector bool short vec_sel (vector bool short, + vector bool short, + vector unsigned short); +vector signed char vec_sel (vector signed char, + vector signed char, + vector bool char); +vector signed char vec_sel (vector signed char, + vector signed char, + vector unsigned char); +vector unsigned char vec_sel (vector unsigned char, + vector unsigned char, + vector bool char); +vector unsigned char vec_sel (vector unsigned char, + vector unsigned char, + vector unsigned char); +vector bool char vec_sel (vector bool char, + vector bool char, + vector bool char); +vector bool char vec_sel (vector bool char, + vector bool char, + vector unsigned char); + +vector signed char vec_sl (vector signed char, + vector unsigned char); +vector unsigned char vec_sl (vector unsigned char, + vector unsigned char); +vector signed short vec_sl (vector signed short, vector unsigned short); +vector unsigned short vec_sl (vector unsigned short, + vector unsigned short); +vector signed int vec_sl (vector signed int, vector unsigned int); +vector unsigned int vec_sl (vector unsigned int, vector unsigned int); + +vector signed int vec_vslw (vector signed int, vector unsigned int); +vector unsigned int vec_vslw (vector unsigned int, vector unsigned int); + +vector signed short vec_vslh (vector signed short, + vector unsigned short); +vector unsigned short vec_vslh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vslb (vector signed char, vector unsigned char); +vector unsigned char vec_vslb (vector unsigned char, + vector unsigned char); + +vector float vec_sld (vector float, vector float, const int); +vector signed int vec_sld (vector signed int, + vector signed int, + const int); +vector unsigned int vec_sld (vector unsigned int, + vector unsigned int, + const int); +vector bool int vec_sld (vector bool int, + vector bool int, + const int); +vector signed short vec_sld (vector signed short, + vector signed short, + const int); +vector unsigned short vec_sld (vector unsigned short, + vector unsigned short, + const int); +vector bool short vec_sld (vector bool short, + vector bool short, + const int); +vector pixel vec_sld (vector pixel, + vector pixel, + const int); +vector signed char vec_sld (vector signed char, + vector signed char, + const int); +vector unsigned char vec_sld (vector unsigned char, + vector unsigned char, + const int); +vector bool char vec_sld (vector bool char, + vector bool char, + const int); + +vector signed int vec_sll (vector signed int, + vector unsigned int); +vector signed int vec_sll (vector signed int, + vector unsigned short); +vector signed int vec_sll (vector signed int, + vector unsigned char); +vector unsigned int vec_sll (vector unsigned int, + vector unsigned int); +vector unsigned int vec_sll (vector unsigned int, + vector unsigned short); +vector unsigned int vec_sll (vector unsigned int, + vector unsigned char); +vector bool int vec_sll (vector bool int, + vector unsigned int); +vector bool int vec_sll (vector bool int, + vector unsigned short); +vector bool int vec_sll (vector bool int, + vector unsigned char); +vector signed short vec_sll (vector signed short, + vector unsigned int); +vector signed short vec_sll (vector signed short, + vector unsigned short); +vector signed short vec_sll (vector signed short, + vector unsigned char); +vector unsigned short vec_sll (vector unsigned short, + vector unsigned int); +vector unsigned short vec_sll (vector unsigned short, + vector unsigned short); +vector unsigned short vec_sll (vector unsigned short, + vector unsigned char); +vector bool short vec_sll (vector bool short, vector unsigned int); +vector bool short vec_sll (vector bool short, vector unsigned short); +vector bool short vec_sll (vector bool short, vector unsigned char); +vector pixel vec_sll (vector pixel, vector unsigned int); +vector pixel vec_sll (vector pixel, vector unsigned short); +vector pixel vec_sll (vector pixel, vector unsigned char); +vector signed char vec_sll (vector signed char, vector unsigned int); +vector signed char vec_sll (vector signed char, vector unsigned short); +vector signed char vec_sll (vector signed char, vector unsigned char); +vector unsigned char vec_sll (vector unsigned char, + vector unsigned int); +vector unsigned char vec_sll (vector unsigned char, + vector unsigned short); +vector unsigned char vec_sll (vector unsigned char, + vector unsigned char); +vector bool char vec_sll (vector bool char, vector unsigned int); +vector bool char vec_sll (vector bool char, vector unsigned short); +vector bool char vec_sll (vector bool char, vector unsigned char); + +vector float vec_slo (vector float, vector signed char); +vector float vec_slo (vector float, vector unsigned char); +vector signed int vec_slo (vector signed int, vector signed char); +vector signed int vec_slo (vector signed int, vector unsigned char); +vector unsigned int vec_slo (vector unsigned int, vector signed char); +vector unsigned int vec_slo (vector unsigned int, vector unsigned char); +vector signed short vec_slo (vector signed short, vector signed char); +vector signed short vec_slo (vector signed short, vector unsigned char); +vector unsigned short vec_slo (vector unsigned short, + vector signed char); +vector unsigned short vec_slo (vector unsigned short, + vector unsigned char); +vector pixel vec_slo (vector pixel, vector signed char); +vector pixel vec_slo (vector pixel, vector unsigned char); +vector signed char vec_slo (vector signed char, vector signed char); +vector signed char vec_slo (vector signed char, vector unsigned char); +vector unsigned char vec_slo (vector unsigned char, vector signed char); +vector unsigned char vec_slo (vector unsigned char, + vector unsigned char); + +vector signed char vec_splat (vector signed char, const int); +vector unsigned char vec_splat (vector unsigned char, const int); +vector bool char vec_splat (vector bool char, const int); +vector signed short vec_splat (vector signed short, const int); +vector unsigned short vec_splat (vector unsigned short, const int); +vector bool short vec_splat (vector bool short, const int); +vector pixel vec_splat (vector pixel, const int); +vector float vec_splat (vector float, const int); +vector signed int vec_splat (vector signed int, const int); +vector unsigned int vec_splat (vector unsigned int, const int); +vector bool int vec_splat (vector bool int, const int); + +vector float vec_vspltw (vector float, const int); +vector signed int vec_vspltw (vector signed int, const int); +vector unsigned int vec_vspltw (vector unsigned int, const int); +vector bool int vec_vspltw (vector bool int, const int); + +vector bool short vec_vsplth (vector bool short, const int); +vector signed short vec_vsplth (vector signed short, const int); +vector unsigned short vec_vsplth (vector unsigned short, const int); +vector pixel vec_vsplth (vector pixel, const int); + +vector signed char vec_vspltb (vector signed char, const int); +vector unsigned char vec_vspltb (vector unsigned char, const int); +vector bool char vec_vspltb (vector bool char, const int); + +vector signed char vec_splat_s8 (const int); + +vector signed short vec_splat_s16 (const int); + +vector signed int vec_splat_s32 (const int); + +vector unsigned char vec_splat_u8 (const int); + +vector unsigned short vec_splat_u16 (const int); + +vector unsigned int vec_splat_u32 (const int); + +vector signed char vec_sr (vector signed char, vector unsigned char); +vector unsigned char vec_sr (vector unsigned char, + vector unsigned char); +vector signed short vec_sr (vector signed short, + vector unsigned short); +vector unsigned short vec_sr (vector unsigned short, + vector unsigned short); +vector signed int vec_sr (vector signed int, vector unsigned int); +vector unsigned int vec_sr (vector unsigned int, vector unsigned int); + +vector signed int vec_vsrw (vector signed int, vector unsigned int); +vector unsigned int vec_vsrw (vector unsigned int, vector unsigned int); + +vector signed short vec_vsrh (vector signed short, + vector unsigned short); +vector unsigned short vec_vsrh (vector unsigned short, + vector unsigned short); + +vector signed char vec_vsrb (vector signed char, vector unsigned char); +vector unsigned char vec_vsrb (vector unsigned char, + vector unsigned char); + +vector signed char vec_sra (vector signed char, vector unsigned char); +vector unsigned char vec_sra (vector unsigned char, + vector unsigned char); +vector signed short vec_sra (vector signed short, + vector unsigned short); +vector unsigned short vec_sra (vector unsigned short, + vector unsigned short); +vector signed int vec_sra (vector signed int, vector unsigned int); +vector unsigned int vec_sra (vector unsigned int, vector unsigned int); + +vector signed int vec_vsraw (vector signed int, vector unsigned int); +vector unsigned int vec_vsraw (vector unsigned int, + vector unsigned int); + +vector signed short vec_vsrah (vector signed short, + vector unsigned short); +vector unsigned short vec_vsrah (vector unsigned short, + vector unsigned short); + +vector signed char vec_vsrab (vector signed char, vector unsigned char); +vector unsigned char vec_vsrab (vector unsigned char, + vector unsigned char); + +vector signed int vec_srl (vector signed int, vector unsigned int); +vector signed int vec_srl (vector signed int, vector unsigned short); +vector signed int vec_srl (vector signed int, vector unsigned char); +vector unsigned int vec_srl (vector unsigned int, vector unsigned int); +vector unsigned int vec_srl (vector unsigned int, + vector unsigned short); +vector unsigned int vec_srl (vector unsigned int, vector unsigned char); +vector bool int vec_srl (vector bool int, vector unsigned int); +vector bool int vec_srl (vector bool int, vector unsigned short); +vector bool int vec_srl (vector bool int, vector unsigned char); +vector signed short vec_srl (vector signed short, vector unsigned int); +vector signed short vec_srl (vector signed short, + vector unsigned short); +vector signed short vec_srl (vector signed short, vector unsigned char); +vector unsigned short vec_srl (vector unsigned short, + vector unsigned int); +vector unsigned short vec_srl (vector unsigned short, + vector unsigned short); +vector unsigned short vec_srl (vector unsigned short, + vector unsigned char); +vector bool short vec_srl (vector bool short, vector unsigned int); +vector bool short vec_srl (vector bool short, vector unsigned short); +vector bool short vec_srl (vector bool short, vector unsigned char); +vector pixel vec_srl (vector pixel, vector unsigned int); +vector pixel vec_srl (vector pixel, vector unsigned short); +vector pixel vec_srl (vector pixel, vector unsigned char); +vector signed char vec_srl (vector signed char, vector unsigned int); +vector signed char vec_srl (vector signed char, vector unsigned short); +vector signed char vec_srl (vector signed char, vector unsigned char); +vector unsigned char vec_srl (vector unsigned char, + vector unsigned int); +vector unsigned char vec_srl (vector unsigned char, + vector unsigned short); +vector unsigned char vec_srl (vector unsigned char, + vector unsigned char); +vector bool char vec_srl (vector bool char, vector unsigned int); +vector bool char vec_srl (vector bool char, vector unsigned short); +vector bool char vec_srl (vector bool char, vector unsigned char); + +vector float vec_sro (vector float, vector signed char); +vector float vec_sro (vector float, vector unsigned char); +vector signed int vec_sro (vector signed int, vector signed char); +vector signed int vec_sro (vector signed int, vector unsigned char); +vector unsigned int vec_sro (vector unsigned int, vector signed char); +vector unsigned int vec_sro (vector unsigned int, vector unsigned char); +vector signed short vec_sro (vector signed short, vector signed char); +vector signed short vec_sro (vector signed short, vector unsigned char); +vector unsigned short vec_sro (vector unsigned short, + vector signed char); +vector unsigned short vec_sro (vector unsigned short, + vector unsigned char); +vector pixel vec_sro (vector pixel, vector signed char); +vector pixel vec_sro (vector pixel, vector unsigned char); +vector signed char vec_sro (vector signed char, vector signed char); +vector signed char vec_sro (vector signed char, vector unsigned char); +vector unsigned char vec_sro (vector unsigned char, vector signed char); +vector unsigned char vec_sro (vector unsigned char, + vector unsigned char); + +void vec_st (vector float, int, vector float *); +void vec_st (vector float, int, float *); +void vec_st (vector signed int, int, vector signed int *); +void vec_st (vector signed int, int, int *); +void vec_st (vector unsigned int, int, vector unsigned int *); +void vec_st (vector unsigned int, int, unsigned int *); +void vec_st (vector bool int, int, vector bool int *); +void vec_st (vector bool int, int, unsigned int *); +void vec_st (vector bool int, int, int *); +void vec_st (vector signed short, int, vector signed short *); +void vec_st (vector signed short, int, short *); +void vec_st (vector unsigned short, int, vector unsigned short *); +void vec_st (vector unsigned short, int, unsigned short *); +void vec_st (vector bool short, int, vector bool short *); +void vec_st (vector bool short, int, unsigned short *); +void vec_st (vector pixel, int, vector pixel *); +void vec_st (vector pixel, int, unsigned short *); +void vec_st (vector pixel, int, short *); +void vec_st (vector bool short, int, short *); +void vec_st (vector signed char, int, vector signed char *); +void vec_st (vector signed char, int, signed char *); +void vec_st (vector unsigned char, int, vector unsigned char *); +void vec_st (vector unsigned char, int, unsigned char *); +void vec_st (vector bool char, int, vector bool char *); +void vec_st (vector bool char, int, unsigned char *); +void vec_st (vector bool char, int, signed char *); + +void vec_ste (vector signed char, int, signed char *); +void vec_ste (vector unsigned char, int, unsigned char *); +void vec_ste (vector bool char, int, signed char *); +void vec_ste (vector bool char, int, unsigned char *); +void vec_ste (vector signed short, int, short *); +void vec_ste (vector unsigned short, int, unsigned short *); +void vec_ste (vector bool short, int, short *); +void vec_ste (vector bool short, int, unsigned short *); +void vec_ste (vector pixel, int, short *); +void vec_ste (vector pixel, int, unsigned short *); +void vec_ste (vector float, int, float *); +void vec_ste (vector signed int, int, int *); +void vec_ste (vector unsigned int, int, unsigned int *); +void vec_ste (vector bool int, int, int *); +void vec_ste (vector bool int, int, unsigned int *); + +void vec_stvewx (vector float, int, float *); +void vec_stvewx (vector signed int, int, int *); +void vec_stvewx (vector unsigned int, int, unsigned int *); +void vec_stvewx (vector bool int, int, int *); +void vec_stvewx (vector bool int, int, unsigned int *); + +void vec_stvehx (vector signed short, int, short *); +void vec_stvehx (vector unsigned short, int, unsigned short *); +void vec_stvehx (vector bool short, int, short *); +void vec_stvehx (vector bool short, int, unsigned short *); +void vec_stvehx (vector pixel, int, short *); +void vec_stvehx (vector pixel, int, unsigned short *); + +void vec_stvebx (vector signed char, int, signed char *); +void vec_stvebx (vector unsigned char, int, unsigned char *); +void vec_stvebx (vector bool char, int, signed char *); +void vec_stvebx (vector bool char, int, unsigned char *); + +void vec_stl (vector float, int, vector float *); +void vec_stl (vector float, int, float *); +void vec_stl (vector signed int, int, vector signed int *); +void vec_stl (vector signed int, int, int *); +void vec_stl (vector unsigned int, int, vector unsigned int *); +void vec_stl (vector unsigned int, int, unsigned int *); +void vec_stl (vector bool int, int, vector bool int *); +void vec_stl (vector bool int, int, unsigned int *); +void vec_stl (vector bool int, int, int *); +void vec_stl (vector signed short, int, vector signed short *); +void vec_stl (vector signed short, int, short *); +void vec_stl (vector unsigned short, int, vector unsigned short *); +void vec_stl (vector unsigned short, int, unsigned short *); +void vec_stl (vector bool short, int, vector bool short *); +void vec_stl (vector bool short, int, unsigned short *); +void vec_stl (vector bool short, int, short *); +void vec_stl (vector pixel, int, vector pixel *); +void vec_stl (vector pixel, int, unsigned short *); +void vec_stl (vector pixel, int, short *); +void vec_stl (vector signed char, int, vector signed char *); +void vec_stl (vector signed char, int, signed char *); +void vec_stl (vector unsigned char, int, vector unsigned char *); +void vec_stl (vector unsigned char, int, unsigned char *); +void vec_stl (vector bool char, int, vector bool char *); +void vec_stl (vector bool char, int, unsigned char *); +void vec_stl (vector bool char, int, signed char *); + +vector signed char vec_sub (vector bool char, vector signed char); +vector signed char vec_sub (vector signed char, vector bool char); +vector signed char vec_sub (vector signed char, vector signed char); +vector unsigned char vec_sub (vector bool char, vector unsigned char); +vector unsigned char vec_sub (vector unsigned char, vector bool char); +vector unsigned char vec_sub (vector unsigned char, + vector unsigned char); +vector signed short vec_sub (vector bool short, vector signed short); +vector signed short vec_sub (vector signed short, vector bool short); +vector signed short vec_sub (vector signed short, vector signed short); +vector unsigned short vec_sub (vector bool short, + vector unsigned short); +vector unsigned short vec_sub (vector unsigned short, + vector bool short); +vector unsigned short vec_sub (vector unsigned short, + vector unsigned short); +vector signed int vec_sub (vector bool int, vector signed int); +vector signed int vec_sub (vector signed int, vector bool int); +vector signed int vec_sub (vector signed int, vector signed int); +vector unsigned int vec_sub (vector bool int, vector unsigned int); +vector unsigned int vec_sub (vector unsigned int, vector bool int); +vector unsigned int vec_sub (vector unsigned int, vector unsigned int); +vector float vec_sub (vector float, vector float); + +vector float vec_vsubfp (vector float, vector float); + +vector signed int vec_vsubuwm (vector bool int, vector signed int); +vector signed int vec_vsubuwm (vector signed int, vector bool int); +vector signed int vec_vsubuwm (vector signed int, vector signed int); +vector unsigned int vec_vsubuwm (vector bool int, vector unsigned int); +vector unsigned int vec_vsubuwm (vector unsigned int, vector bool int); +vector unsigned int vec_vsubuwm (vector unsigned int, + vector unsigned int); + +vector signed short vec_vsubuhm (vector bool short, + vector signed short); +vector signed short vec_vsubuhm (vector signed short, + vector bool short); +vector signed short vec_vsubuhm (vector signed short, + vector signed short); +vector unsigned short vec_vsubuhm (vector bool short, + vector unsigned short); +vector unsigned short vec_vsubuhm (vector unsigned short, + vector bool short); +vector unsigned short vec_vsubuhm (vector unsigned short, + vector unsigned short); + +vector signed char vec_vsububm (vector bool char, vector signed char); +vector signed char vec_vsububm (vector signed char, vector bool char); +vector signed char vec_vsububm (vector signed char, vector signed char); +vector unsigned char vec_vsububm (vector bool char, + vector unsigned char); +vector unsigned char vec_vsububm (vector unsigned char, + vector bool char); +vector unsigned char vec_vsububm (vector unsigned char, + vector unsigned char); + +vector unsigned int vec_subc (vector unsigned int, vector unsigned int); + +vector unsigned char vec_subs (vector bool char, vector unsigned char); +vector unsigned char vec_subs (vector unsigned char, vector bool char); +vector unsigned char vec_subs (vector unsigned char, + vector unsigned char); +vector signed char vec_subs (vector bool char, vector signed char); +vector signed char vec_subs (vector signed char, vector bool char); +vector signed char vec_subs (vector signed char, vector signed char); +vector unsigned short vec_subs (vector bool short, + vector unsigned short); +vector unsigned short vec_subs (vector unsigned short, + vector bool short); +vector unsigned short vec_subs (vector unsigned short, + vector unsigned short); +vector signed short vec_subs (vector bool short, vector signed short); +vector signed short vec_subs (vector signed short, vector bool short); +vector signed short vec_subs (vector signed short, vector signed short); +vector unsigned int vec_subs (vector bool int, vector unsigned int); +vector unsigned int vec_subs (vector unsigned int, vector bool int); +vector unsigned int vec_subs (vector unsigned int, vector unsigned int); +vector signed int vec_subs (vector bool int, vector signed int); +vector signed int vec_subs (vector signed int, vector bool int); +vector signed int vec_subs (vector signed int, vector signed int); + +vector signed int vec_vsubsws (vector bool int, vector signed int); +vector signed int vec_vsubsws (vector signed int, vector bool int); +vector signed int vec_vsubsws (vector signed int, vector signed int); + +vector unsigned int vec_vsubuws (vector bool int, vector unsigned int); +vector unsigned int vec_vsubuws (vector unsigned int, vector bool int); +vector unsigned int vec_vsubuws (vector unsigned int, + vector unsigned int); + +vector signed short vec_vsubshs (vector bool short, + vector signed short); +vector signed short vec_vsubshs (vector signed short, + vector bool short); +vector signed short vec_vsubshs (vector signed short, + vector signed short); + +vector unsigned short vec_vsubuhs (vector bool short, + vector unsigned short); +vector unsigned short vec_vsubuhs (vector unsigned short, + vector bool short); +vector unsigned short vec_vsubuhs (vector unsigned short, + vector unsigned short); + +vector signed char vec_vsubsbs (vector bool char, vector signed char); +vector signed char vec_vsubsbs (vector signed char, vector bool char); +vector signed char vec_vsubsbs (vector signed char, vector signed char); + +vector unsigned char vec_vsububs (vector bool char, + vector unsigned char); +vector unsigned char vec_vsububs (vector unsigned char, + vector bool char); +vector unsigned char vec_vsububs (vector unsigned char, + vector unsigned char); + +vector unsigned int vec_sum4s (vector unsigned char, + vector unsigned int); +vector signed int vec_sum4s (vector signed char, vector signed int); +vector signed int vec_sum4s (vector signed short, vector signed int); + +vector signed int vec_vsum4shs (vector signed short, vector signed int); + +vector signed int vec_vsum4sbs (vector signed char, vector signed int); + +vector unsigned int vec_vsum4ubs (vector unsigned char, + vector unsigned int); + +vector signed int vec_sum2s (vector signed int, vector signed int); + +vector signed int vec_sums (vector signed int, vector signed int); + +vector float vec_trunc (vector float); + +vector signed short vec_unpackh (vector signed char); +vector bool short vec_unpackh (vector bool char); +vector signed int vec_unpackh (vector signed short); +vector bool int vec_unpackh (vector bool short); +vector unsigned int vec_unpackh (vector pixel); + +vector bool int vec_vupkhsh (vector bool short); +vector signed int vec_vupkhsh (vector signed short); + +vector unsigned int vec_vupkhpx (vector pixel); + +vector bool short vec_vupkhsb (vector bool char); +vector signed short vec_vupkhsb (vector signed char); + +vector signed short vec_unpackl (vector signed char); +vector bool short vec_unpackl (vector bool char); +vector unsigned int vec_unpackl (vector pixel); +vector signed int vec_unpackl (vector signed short); +vector bool int vec_unpackl (vector bool short); + +vector unsigned int vec_vupklpx (vector pixel); + +vector bool int vec_vupklsh (vector bool short); +vector signed int vec_vupklsh (vector signed short); + +vector bool short vec_vupklsb (vector bool char); +vector signed short vec_vupklsb (vector signed char); + +vector float vec_xor (vector float, vector float); +vector float vec_xor (vector float, vector bool int); +vector float vec_xor (vector bool int, vector float); +vector bool int vec_xor (vector bool int, vector bool int); +vector signed int vec_xor (vector bool int, vector signed int); +vector signed int vec_xor (vector signed int, vector bool int); +vector signed int vec_xor (vector signed int, vector signed int); +vector unsigned int vec_xor (vector bool int, vector unsigned int); +vector unsigned int vec_xor (vector unsigned int, vector bool int); +vector unsigned int vec_xor (vector unsigned int, vector unsigned int); +vector bool short vec_xor (vector bool short, vector bool short); +vector signed short vec_xor (vector bool short, vector signed short); +vector signed short vec_xor (vector signed short, vector bool short); +vector signed short vec_xor (vector signed short, vector signed short); +vector unsigned short vec_xor (vector bool short, + vector unsigned short); +vector unsigned short vec_xor (vector unsigned short, + vector bool short); +vector unsigned short vec_xor (vector unsigned short, + vector unsigned short); +vector signed char vec_xor (vector bool char, vector signed char); +vector bool char vec_xor (vector bool char, vector bool char); +vector signed char vec_xor (vector signed char, vector bool char); +vector signed char vec_xor (vector signed char, vector signed char); +vector unsigned char vec_xor (vector bool char, vector unsigned char); +vector unsigned char vec_xor (vector unsigned char, vector bool char); +vector unsigned char vec_xor (vector unsigned char, + vector unsigned char); + +int vec_all_eq (vector signed char, vector bool char); +int vec_all_eq (vector signed char, vector signed char); +int vec_all_eq (vector unsigned char, vector bool char); +int vec_all_eq (vector unsigned char, vector unsigned char); +int vec_all_eq (vector bool char, vector bool char); +int vec_all_eq (vector bool char, vector unsigned char); +int vec_all_eq (vector bool char, vector signed char); +int vec_all_eq (vector signed short, vector bool short); +int vec_all_eq (vector signed short, vector signed short); +int vec_all_eq (vector unsigned short, vector bool short); +int vec_all_eq (vector unsigned short, vector unsigned short); +int vec_all_eq (vector bool short, vector bool short); +int vec_all_eq (vector bool short, vector unsigned short); +int vec_all_eq (vector bool short, vector signed short); +int vec_all_eq (vector pixel, vector pixel); +int vec_all_eq (vector signed int, vector bool int); +int vec_all_eq (vector signed int, vector signed int); +int vec_all_eq (vector unsigned int, vector bool int); +int vec_all_eq (vector unsigned int, vector unsigned int); +int vec_all_eq (vector bool int, vector bool int); +int vec_all_eq (vector bool int, vector unsigned int); +int vec_all_eq (vector bool int, vector signed int); +int vec_all_eq (vector float, vector float); + +int vec_all_ge (vector bool char, vector unsigned char); +int vec_all_ge (vector unsigned char, vector bool char); +int vec_all_ge (vector unsigned char, vector unsigned char); +int vec_all_ge (vector bool char, vector signed char); +int vec_all_ge (vector signed char, vector bool char); +int vec_all_ge (vector signed char, vector signed char); +int vec_all_ge (vector bool short, vector unsigned short); +int vec_all_ge (vector unsigned short, vector bool short); +int vec_all_ge (vector unsigned short, vector unsigned short); +int vec_all_ge (vector signed short, vector signed short); +int vec_all_ge (vector bool short, vector signed short); +int vec_all_ge (vector signed short, vector bool short); +int vec_all_ge (vector bool int, vector unsigned int); +int vec_all_ge (vector unsigned int, vector bool int); +int vec_all_ge (vector unsigned int, vector unsigned int); +int vec_all_ge (vector bool int, vector signed int); +int vec_all_ge (vector signed int, vector bool int); +int vec_all_ge (vector signed int, vector signed int); +int vec_all_ge (vector float, vector float); + +int vec_all_gt (vector bool char, vector unsigned char); +int vec_all_gt (vector unsigned char, vector bool char); +int vec_all_gt (vector unsigned char, vector unsigned char); +int vec_all_gt (vector bool char, vector signed char); +int vec_all_gt (vector signed char, vector bool char); +int vec_all_gt (vector signed char, vector signed char); +int vec_all_gt (vector bool short, vector unsigned short); +int vec_all_gt (vector unsigned short, vector bool short); +int vec_all_gt (vector unsigned short, vector unsigned short); +int vec_all_gt (vector bool short, vector signed short); +int vec_all_gt (vector signed short, vector bool short); +int vec_all_gt (vector signed short, vector signed short); +int vec_all_gt (vector bool int, vector unsigned int); +int vec_all_gt (vector unsigned int, vector bool int); +int vec_all_gt (vector unsigned int, vector unsigned int); +int vec_all_gt (vector bool int, vector signed int); +int vec_all_gt (vector signed int, vector bool int); +int vec_all_gt (vector signed int, vector signed int); +int vec_all_gt (vector float, vector float); + +int vec_all_in (vector float, vector float); + +int vec_all_le (vector bool char, vector unsigned char); +int vec_all_le (vector unsigned char, vector bool char); +int vec_all_le (vector unsigned char, vector unsigned char); +int vec_all_le (vector bool char, vector signed char); +int vec_all_le (vector signed char, vector bool char); +int vec_all_le (vector signed char, vector signed char); +int vec_all_le (vector bool short, vector unsigned short); +int vec_all_le (vector unsigned short, vector bool short); +int vec_all_le (vector unsigned short, vector unsigned short); +int vec_all_le (vector bool short, vector signed short); +int vec_all_le (vector signed short, vector bool short); +int vec_all_le (vector signed short, vector signed short); +int vec_all_le (vector bool int, vector unsigned int); +int vec_all_le (vector unsigned int, vector bool int); +int vec_all_le (vector unsigned int, vector unsigned int); +int vec_all_le (vector bool int, vector signed int); +int vec_all_le (vector signed int, vector bool int); +int vec_all_le (vector signed int, vector signed int); +int vec_all_le (vector float, vector float); + +int vec_all_lt (vector bool char, vector unsigned char); +int vec_all_lt (vector unsigned char, vector bool char); +int vec_all_lt (vector unsigned char, vector unsigned char); +int vec_all_lt (vector bool char, vector signed char); +int vec_all_lt (vector signed char, vector bool char); +int vec_all_lt (vector signed char, vector signed char); +int vec_all_lt (vector bool short, vector unsigned short); +int vec_all_lt (vector unsigned short, vector bool short); +int vec_all_lt (vector unsigned short, vector unsigned short); +int vec_all_lt (vector bool short, vector signed short); +int vec_all_lt (vector signed short, vector bool short); +int vec_all_lt (vector signed short, vector signed short); +int vec_all_lt (vector bool int, vector unsigned int); +int vec_all_lt (vector unsigned int, vector bool int); +int vec_all_lt (vector unsigned int, vector unsigned int); +int vec_all_lt (vector bool int, vector signed int); +int vec_all_lt (vector signed int, vector bool int); +int vec_all_lt (vector signed int, vector signed int); +int vec_all_lt (vector float, vector float); + +int vec_all_nan (vector float); + +int vec_all_ne (vector signed char, vector bool char); +int vec_all_ne (vector signed char, vector signed char); +int vec_all_ne (vector unsigned char, vector bool char); +int vec_all_ne (vector unsigned char, vector unsigned char); +int vec_all_ne (vector bool char, vector bool char); +int vec_all_ne (vector bool char, vector unsigned char); +int vec_all_ne (vector bool char, vector signed char); +int vec_all_ne (vector signed short, vector bool short); +int vec_all_ne (vector signed short, vector signed short); +int vec_all_ne (vector unsigned short, vector bool short); +int vec_all_ne (vector unsigned short, vector unsigned short); +int vec_all_ne (vector bool short, vector bool short); +int vec_all_ne (vector bool short, vector unsigned short); +int vec_all_ne (vector bool short, vector signed short); +int vec_all_ne (vector pixel, vector pixel); +int vec_all_ne (vector signed int, vector bool int); +int vec_all_ne (vector signed int, vector signed int); +int vec_all_ne (vector unsigned int, vector bool int); +int vec_all_ne (vector unsigned int, vector unsigned int); +int vec_all_ne (vector bool int, vector bool int); +int vec_all_ne (vector bool int, vector unsigned int); +int vec_all_ne (vector bool int, vector signed int); +int vec_all_ne (vector float, vector float); + +int vec_all_nge (vector float, vector float); + +int vec_all_ngt (vector float, vector float); + +int vec_all_nle (vector float, vector float); + +int vec_all_nlt (vector float, vector float); + +int vec_all_numeric (vector float); + +int vec_any_eq (vector signed char, vector bool char); +int vec_any_eq (vector signed char, vector signed char); +int vec_any_eq (vector unsigned char, vector bool char); +int vec_any_eq (vector unsigned char, vector unsigned char); +int vec_any_eq (vector bool char, vector bool char); +int vec_any_eq (vector bool char, vector unsigned char); +int vec_any_eq (vector bool char, vector signed char); +int vec_any_eq (vector signed short, vector bool short); +int vec_any_eq (vector signed short, vector signed short); +int vec_any_eq (vector unsigned short, vector bool short); +int vec_any_eq (vector unsigned short, vector unsigned short); +int vec_any_eq (vector bool short, vector bool short); +int vec_any_eq (vector bool short, vector unsigned short); +int vec_any_eq (vector bool short, vector signed short); +int vec_any_eq (vector pixel, vector pixel); +int vec_any_eq (vector signed int, vector bool int); +int vec_any_eq (vector signed int, vector signed int); +int vec_any_eq (vector unsigned int, vector bool int); +int vec_any_eq (vector unsigned int, vector unsigned int); +int vec_any_eq (vector bool int, vector bool int); +int vec_any_eq (vector bool int, vector unsigned int); +int vec_any_eq (vector bool int, vector signed int); +int vec_any_eq (vector float, vector float); + +int vec_any_ge (vector signed char, vector bool char); +int vec_any_ge (vector unsigned char, vector bool char); +int vec_any_ge (vector unsigned char, vector unsigned char); +int vec_any_ge (vector signed char, vector signed char); +int vec_any_ge (vector bool char, vector unsigned char); +int vec_any_ge (vector bool char, vector signed char); +int vec_any_ge (vector unsigned short, vector bool short); +int vec_any_ge (vector unsigned short, vector unsigned short); +int vec_any_ge (vector signed short, vector signed short); +int vec_any_ge (vector signed short, vector bool short); +int vec_any_ge (vector bool short, vector unsigned short); +int vec_any_ge (vector bool short, vector signed short); +int vec_any_ge (vector signed int, vector bool int); +int vec_any_ge (vector unsigned int, vector bool int); +int vec_any_ge (vector unsigned int, vector unsigned int); +int vec_any_ge (vector signed int, vector signed int); +int vec_any_ge (vector bool int, vector unsigned int); +int vec_any_ge (vector bool int, vector signed int); +int vec_any_ge (vector float, vector float); + +int vec_any_gt (vector bool char, vector unsigned char); +int vec_any_gt (vector unsigned char, vector bool char); +int vec_any_gt (vector unsigned char, vector unsigned char); +int vec_any_gt (vector bool char, vector signed char); +int vec_any_gt (vector signed char, vector bool char); +int vec_any_gt (vector signed char, vector signed char); +int vec_any_gt (vector bool short, vector unsigned short); +int vec_any_gt (vector unsigned short, vector bool short); +int vec_any_gt (vector unsigned short, vector unsigned short); +int vec_any_gt (vector bool short, vector signed short); +int vec_any_gt (vector signed short, vector bool short); +int vec_any_gt (vector signed short, vector signed short); +int vec_any_gt (vector bool int, vector unsigned int); +int vec_any_gt (vector unsigned int, vector bool int); +int vec_any_gt (vector unsigned int, vector unsigned int); +int vec_any_gt (vector bool int, vector signed int); +int vec_any_gt (vector signed int, vector bool int); +int vec_any_gt (vector signed int, vector signed int); +int vec_any_gt (vector float, vector float); + +int vec_any_le (vector bool char, vector unsigned char); +int vec_any_le (vector unsigned char, vector bool char); +int vec_any_le (vector unsigned char, vector unsigned char); +int vec_any_le (vector bool char, vector signed char); +int vec_any_le (vector signed char, vector bool char); +int vec_any_le (vector signed char, vector signed char); +int vec_any_le (vector bool short, vector unsigned short); +int vec_any_le (vector unsigned short, vector bool short); +int vec_any_le (vector unsigned short, vector unsigned short); +int vec_any_le (vector bool short, vector signed short); +int vec_any_le (vector signed short, vector bool short); +int vec_any_le (vector signed short, vector signed short); +int vec_any_le (vector bool int, vector unsigned int); +int vec_any_le (vector unsigned int, vector bool int); +int vec_any_le (vector unsigned int, vector unsigned int); +int vec_any_le (vector bool int, vector signed int); +int vec_any_le (vector signed int, vector bool int); +int vec_any_le (vector signed int, vector signed int); +int vec_any_le (vector float, vector float); + +int vec_any_lt (vector bool char, vector unsigned char); +int vec_any_lt (vector unsigned char, vector bool char); +int vec_any_lt (vector unsigned char, vector unsigned char); +int vec_any_lt (vector bool char, vector signed char); +int vec_any_lt (vector signed char, vector bool char); +int vec_any_lt (vector signed char, vector signed char); +int vec_any_lt (vector bool short, vector unsigned short); +int vec_any_lt (vector unsigned short, vector bool short); +int vec_any_lt (vector unsigned short, vector unsigned short); +int vec_any_lt (vector bool short, vector signed short); +int vec_any_lt (vector signed short, vector bool short); +int vec_any_lt (vector signed short, vector signed short); +int vec_any_lt (vector bool int, vector unsigned int); +int vec_any_lt (vector unsigned int, vector bool int); +int vec_any_lt (vector unsigned int, vector unsigned int); +int vec_any_lt (vector bool int, vector signed int); +int vec_any_lt (vector signed int, vector bool int); +int vec_any_lt (vector signed int, vector signed int); +int vec_any_lt (vector float, vector float); + +int vec_any_nan (vector float); + +int vec_any_ne (vector signed char, vector bool char); +int vec_any_ne (vector signed char, vector signed char); +int vec_any_ne (vector unsigned char, vector bool char); +int vec_any_ne (vector unsigned char, vector unsigned char); +int vec_any_ne (vector bool char, vector bool char); +int vec_any_ne (vector bool char, vector unsigned char); +int vec_any_ne (vector bool char, vector signed char); +int vec_any_ne (vector signed short, vector bool short); +int vec_any_ne (vector signed short, vector signed short); +int vec_any_ne (vector unsigned short, vector bool short); +int vec_any_ne (vector unsigned short, vector unsigned short); +int vec_any_ne (vector bool short, vector bool short); +int vec_any_ne (vector bool short, vector unsigned short); +int vec_any_ne (vector bool short, vector signed short); +int vec_any_ne (vector pixel, vector pixel); +int vec_any_ne (vector signed int, vector bool int); +int vec_any_ne (vector signed int, vector signed int); +int vec_any_ne (vector unsigned int, vector bool int); +int vec_any_ne (vector unsigned int, vector unsigned int); +int vec_any_ne (vector bool int, vector bool int); +int vec_any_ne (vector bool int, vector unsigned int); +int vec_any_ne (vector bool int, vector signed int); +int vec_any_ne (vector float, vector float); + +int vec_any_nge (vector float, vector float); + +int vec_any_ngt (vector float, vector float); + +int vec_any_nle (vector float, vector float); + +int vec_any_nlt (vector float, vector float); + +int vec_any_numeric (vector float); + +int vec_any_out (vector float, vector float); +@end smallexample + +@node SPARC VIS Built-in Functions +@subsection SPARC VIS Built-in Functions + +GCC supports SIMD operations on the SPARC using both the generic vector +extensions (@pxref{Vector Extensions}) as well as built-in functions for +the SPARC Visual Instruction Set (VIS). When you use the @option{-mvis} +switch, the VIS extension is exposed as the following built-in functions: + +@smallexample +typedef int v2si __attribute__ ((vector_size (8))); +typedef short v4hi __attribute__ ((vector_size (8))); +typedef short v2hi __attribute__ ((vector_size (4))); +typedef char v8qi __attribute__ ((vector_size (8))); +typedef char v4qi __attribute__ ((vector_size (4))); + +void * __builtin_vis_alignaddr (void *, long); +int64_t __builtin_vis_faligndatadi (int64_t, int64_t); +v2si __builtin_vis_faligndatav2si (v2si, v2si); +v4hi __builtin_vis_faligndatav4hi (v4si, v4si); +v8qi __builtin_vis_faligndatav8qi (v8qi, v8qi); + +v4hi __builtin_vis_fexpand (v4qi); + +v4hi __builtin_vis_fmul8x16 (v4qi, v4hi); +v4hi __builtin_vis_fmul8x16au (v4qi, v4hi); +v4hi __builtin_vis_fmul8x16al (v4qi, v4hi); +v4hi __builtin_vis_fmul8sux16 (v8qi, v4hi); +v4hi __builtin_vis_fmul8ulx16 (v8qi, v4hi); +v2si __builtin_vis_fmuld8sux16 (v4qi, v2hi); +v2si __builtin_vis_fmuld8ulx16 (v4qi, v2hi); + +v4qi __builtin_vis_fpack16 (v4hi); +v8qi __builtin_vis_fpack32 (v2si, v2si); +v2hi __builtin_vis_fpackfix (v2si); +v8qi __builtin_vis_fpmerge (v4qi, v4qi); + +int64_t __builtin_vis_pdist (v8qi, v8qi, int64_t); +@end smallexample + +@node Target Format Checks +@section Format Checks Specific to Particular Target Machines + +For some target machines, GCC supports additional options to the +format attribute +(@pxref{Function Attributes,,Declaring Attributes of Functions}). + +@menu +* Solaris Format Checks:: +@end menu + +@node Solaris Format Checks +@subsection Solaris Format Checks + +Solaris targets support the @code{cmn_err} (or @code{__cmn_err__}) format +check. @code{cmn_err} accepts a subset of the standard @code{printf} +conversions, and the two-argument @code{%b} conversion for displaying +bit-fields. See the Solaris man page for @code{cmn_err} for more information. + +@node Pragmas +@section Pragmas Accepted by GCC +@cindex pragmas +@cindex #pragma + +GCC supports several types of pragmas, primarily in order to compile +code originally written for other compilers. Note that in general +we do not recommend the use of pragmas; @xref{Function Attributes}, +for further explanation. + +@menu +* ARM Pragmas:: +* M32C Pragmas:: +* RS/6000 and PowerPC Pragmas:: +* Darwin Pragmas:: +* Solaris Pragmas:: +* Symbol-Renaming Pragmas:: +* Structure-Packing Pragmas:: +* Weak Pragmas:: +* Diagnostic Pragmas:: +* Visibility Pragmas:: +@end menu + +@node ARM Pragmas +@subsection ARM Pragmas + +The ARM target defines pragmas for controlling the default addition of +@code{long_call} and @code{short_call} attributes to functions. +@xref{Function Attributes}, for information about the effects of these +attributes. + +@table @code +@item long_calls +@cindex pragma, long_calls +Set all subsequent functions to have the @code{long_call} attribute. + +@item no_long_calls +@cindex pragma, no_long_calls +Set all subsequent functions to have the @code{short_call} attribute. + +@item long_calls_off +@cindex pragma, long_calls_off +Do not affect the @code{long_call} or @code{short_call} attributes of +subsequent functions. +@end table + +@node M32C Pragmas +@subsection M32C Pragmas + +@table @code +@item memregs @var{number} +@cindex pragma, memregs +Overrides the command line option @code{-memregs=} for the current +file. Use with care! This pragma must be before any function in the +file, and mixing different memregs values in different objects may +make them incompatible. This pragma is useful when a +performance-critical function uses a memreg for temporary values, +as it may allow you to reduce the number of memregs used. + +@end table + +@node RS/6000 and PowerPC Pragmas +@subsection RS/6000 and PowerPC Pragmas + +The RS/6000 and PowerPC targets define one pragma for controlling +whether or not the @code{longcall} attribute is added to function +declarations by default. This pragma overrides the @option{-mlongcall} +option, but not the @code{longcall} and @code{shortcall} attributes. +@xref{RS/6000 and PowerPC Options}, for more information about when long +calls are and are not necessary. + +@table @code +@item longcall (1) +@cindex pragma, longcall +Apply the @code{longcall} attribute to all subsequent function +declarations. + +@item longcall (0) +Do not apply the @code{longcall} attribute to subsequent function +declarations. +@end table + +@c Describe c4x pragmas here. +@c Describe h8300 pragmas here. +@c Describe sh pragmas here. +@c Describe v850 pragmas here. + +@node Darwin Pragmas +@subsection Darwin Pragmas + +The following pragmas are available for all architectures running the +Darwin operating system. These are useful for compatibility with other +Mac OS compilers. + +@table @code +@item mark @var{tokens}@dots{} +@cindex pragma, mark +This pragma is accepted, but has no effect. + +@item options align=@var{alignment} +@cindex pragma, options align +This pragma sets the alignment of fields in structures. The values of +@var{alignment} may be @code{mac68k}, to emulate m68k alignment, or +@code{power}, to emulate PowerPC alignment. Uses of this pragma nest +properly; to restore the previous setting, use @code{reset} for the +@var{alignment}. + +@c APPLE LOCAL begin radar 4827197 +The @code{power} setting, when compiling for the Intel target, does not +fully emulate the alignments on native PowerPC targets. When the first +field within a struct is of type @code{double}, this causes the struct +to be 8-byte aligned on PowerPC target, but only 4-byte aligned on +Intel target. When such a struct is nested within another aggregate, +differing layouts on the two targets can occur. In such a case, a dummy +field @code{char : 0;} can be inserted before the @code{double} to achieve +the same layout on both targets. +@c APPLE LOCAL end radar 4827197 + +@item segment @var{tokens}@dots{} +@cindex pragma, segment +This pragma is accepted, but has no effect. + +@item unused (@var{var} [, @var{var}]@dots{}) +@cindex pragma, unused +This pragma declares variables to be possibly unused. GCC will not +produce warnings for the listed variables. The effect is similar to +that of the @code{unused} attribute, except that this pragma may appear +anywhere within the variables' scopes. + +@c APPLE LOCAL begin optimization pragmas 3124235/3420242 +@item optimization_level @{ 0 | 1 | 2 | 3 | reset @} +@item optimize_for_size @{ on | off | reset @} +@item GCC optimization_level @{ 0 | 1 | 2 | 3 | reset @} +@item GCC optimize_for_size @{ on | off | reset @} +@cindex pragma, optimization_level +(These pragmas are APPLE ONLY.) + +These pragmas set the current optimization level, similar but not identical +to -O0 through -O3, or -Os, on the command line. These pragmas form a +stack; the "reset" argument pops the stack, restoring the optimization level +to what it was before the previous optimization pragma. The optimization +level in effect at the beginning of each function definition is applied to +that function. Currently, the pragmas will not affect optimizations whose +implementation is based on whole-file analysis; this notably includes +inlining and strict aliasing. Also, the feature currently doesn't apply +to functions whose body is within a class definition (that is, such +functions are compiled with the command line options). + +The versions without "GCC" have the same syntax and similar effect as +CodeWarrior pragmas (although since the optimizations performed by +the compilers are not identical, the effect of the options won't be +either). These may be convenient for existing code. The versions +with "GCC" are recommended for new code. +@end table +@c APPLE LOCAL end optimization pragmas 3124235/3420242 + +@node Solaris Pragmas +@subsection Solaris Pragmas + +The Solaris target supports @code{#pragma redefine_extname} +(@pxref{Symbol-Renaming Pragmas}). It also supports additional +@code{#pragma} directives for compatibility with the system compiler. + +@table @code +@item align @var{alignment} (@var{variable} [, @var{variable}]...) +@cindex pragma, align + +Increase the minimum alignment of each @var{variable} to @var{alignment}. +This is the same as GCC's @code{aligned} attribute @pxref{Variable +Attributes}). Macro expansion occurs on the arguments to this pragma +when compiling C and Objective-C. It does not currently occur when +compiling C++, but this is a bug which may be fixed in a future +release. + +@item fini (@var{function} [, @var{function}]...) +@cindex pragma, fini + +This pragma causes each listed @var{function} to be called after +main, or during shared module unloading, by adding a call to the +@code{.fini} section. + +@item init (@var{function} [, @var{function}]...) +@cindex pragma, init + +This pragma causes each listed @var{function} to be called during +initialization (before @code{main}) or during shared module loading, by +adding a call to the @code{.init} section. + +@end table + +@node Symbol-Renaming Pragmas +@subsection Symbol-Renaming Pragmas + +For compatibility with the Solaris and Tru64 UNIX system headers, GCC +supports two @code{#pragma} directives which change the name used in +assembly for a given declaration. These pragmas are only available on +platforms whose system headers need them. To get this effect on all +platforms supported by GCC, use the asm labels extension (@pxref{Asm +Labels}). + +@table @code +@item redefine_extname @var{oldname} @var{newname} +@cindex pragma, redefine_extname + +This pragma gives the C function @var{oldname} the assembly symbol +@var{newname}. The preprocessor macro @code{__PRAGMA_REDEFINE_EXTNAME} +will be defined if this pragma is available (currently only on +Solaris). + +@item extern_prefix @var{string} +@cindex pragma, extern_prefix + +This pragma causes all subsequent external function and variable +declarations to have @var{string} prepended to their assembly symbols. +This effect may be terminated with another @code{extern_prefix} pragma +whose argument is an empty string. The preprocessor macro +@code{__PRAGMA_EXTERN_PREFIX} will be defined if this pragma is +available (currently only on Tru64 UNIX)@. +@end table + +These pragmas and the asm labels extension interact in a complicated +manner. Here are some corner cases you may want to be aware of. + +@enumerate +@item Both pragmas silently apply only to declarations with external +linkage. Asm labels do not have this restriction. + +@item In C++, both pragmas silently apply only to declarations with +``C'' linkage. Again, asm labels do not have this restriction. + +@item If any of the three ways of changing the assembly name of a +declaration is applied to a declaration whose assembly name has +already been determined (either by a previous use of one of these +features, or because the compiler needed the assembly name in order to +generate code), and the new name is different, a warning issues and +the name does not change. + +@item The @var{oldname} used by @code{#pragma redefine_extname} is +always the C-language name. + +@item If @code{#pragma extern_prefix} is in effect, and a declaration +occurs with an asm label attached, the prefix is silently ignored for +that declaration. + +@item If @code{#pragma extern_prefix} and @code{#pragma redefine_extname} +apply to the same declaration, whichever triggered first wins, and a +warning issues if they contradict each other. (We would like to have +@code{#pragma redefine_extname} always win, for consistency with asm +labels, but if @code{#pragma extern_prefix} triggers first we have no +way of knowing that that happened.) +@end enumerate + +@node Structure-Packing Pragmas +@subsection Structure-Packing Pragmas + +@c APPLE LOCAL begin radar 4679943 +For compatibility with Win32, GCC supports a set of @code{#pragma} +directives which change the maximum alignment of members of structures +(other than zero-width bitfields), unions, and classes subsequently +defined. The @var{n} value below always is required to be a small power +of two and specifies the new maximum alignment in bytes. + +@enumerate +@c APPLE LOCAL prune man page +@ignore +@item @code{#pragma pack(@var{n})} simply sets the new alignment. +@item @code{#pragma pack()} sets the alignment to the one that was in +effect when compilation started (see also command line option +@option{-fpack-struct[=<n>]} @pxref{Code Gen Options}). +@item @code{#pragma pack(push[,@var{n}])} pushes the current alignment +setting on an internal stack and then optionally sets the new alignment. +@item @code{#pragma pack(pop)} restores the alignment setting to the one +saved at the top of the internal stack (and removes that stack entry). +Note that @code{#pragma pack([@var{n}])} does not influence this internal +stack; thus it is possible to have @code{#pragma pack(push)} followed by +multiple @code{#pragma pack(@var{n})} instances and finalized by a single +@code{#pragma pack(pop)}. +@c APPLE LOCAL prune man page +@end ignore + +@item @code{#pragma pack(@var{n})} pushes the current maximum alignment setting +onto an internal stack and then sets the new maximum alignment. (APPLE ONLY) +@item @code{#pragma pack()} acts like a @code{#pragma pack(pop)} directive. +(APPLE ONLY) +@item @code{#pragma pack(push[,@var{n}])} pushes the current maximum alignment +setting onto an internal stack and then optionally sets the new maximum +alignment. +@item @code{#pragma pack(pop)} restores the maximum alignment setting to the +one saved at the top of the internal stack (and removes that stack entry). +@end enumerate +@c APPLE LOCAL end radar 4679943 + +Some targets, e.g. i386 and powerpc, support the @code{ms_struct} +@code{#pragma} which lays out a structure as the documented +@code{__attribute__ ((ms_struct))}. +@enumerate +@item @code{#pragma ms_struct on} turns on the layout for structures +declared. +@item @code{#pragma ms_struct off} turns off the layout for structures +declared. +@item @code{#pragma ms_struct reset} goes back to the default layout. +@end enumerate + +@node Weak Pragmas +@subsection Weak Pragmas + +For compatibility with SVR4, GCC supports a set of @code{#pragma} +directives for declaring symbols to be weak, and defining weak +aliases. + +@table @code +@item #pragma weak @var{symbol} +@cindex pragma, weak +This pragma declares @var{symbol} to be weak, as if the declaration +had the attribute of the same name. The pragma may appear before +or after the declaration of @var{symbol}, but must appear before +either its first use or its definition. It is not an error for +@var{symbol} to never be defined at all. + +@item #pragma weak @var{symbol1} = @var{symbol2} +This pragma declares @var{symbol1} to be a weak alias of @var{symbol2}. +It is an error if @var{symbol2} is not defined in the current +translation unit. +@end table + +@node Diagnostic Pragmas +@subsection Diagnostic Pragmas + +GCC allows the user to selectively enable or disable certain types of +diagnostics, and change the kind of the diagnostic. For example, a +project's policy might require that all sources compile with +@option{-Werror} but certain files might have exceptions allowing +specific types of warnings. Or, a project might selectively enable +diagnostics and treat them as errors depending on which preprocessor +macros are defined. + +@table @code +@item #pragma GCC diagnostic @var{kind} @var{option} +@cindex pragma, diagnostic + +Modifies the disposition of a diagnostic. Note that not all +diagnostics are modifiable; at the moment only warnings (normally +controlled by @samp{-W...}) can be controlled, and not all of them. +Use @option{-fdiagnostics-show-option} to determine which diagnostics +are controllable and which option controls them. + +@var{kind} is @samp{error} to treat this diagnostic as an error, +@samp{warning} to treat it like a warning (even if @option{-Werror} is +in effect), or @samp{ignored} if the diagnostic is to be ignored. +@var{option} is a double quoted string which matches the command line +option. + +@example +#pragma GCC diagnostic warning "-Wformat" +#pragma GCC diagnostic error "-Wformat" +#pragma GCC diagnostic ignored "-Wformat" +@end example + +Note that these pragmas override any command line options. Also, +while it is syntactically valid to put these pragmas anywhere in your +sources, the only supported location for them is before any data or +functions are defined. Doing otherwise may result in unpredictable +results depending on how the optimizer manages your sources. If the +same option is listed multiple times, the last one specified is the +one that is in effect. This pragma is not intended to be a general +purpose replacement for command line options, but for implementing +strict control over project policies. + +@end table + +@node Visibility Pragmas +@subsection Visibility Pragmas + +@table @code +@item #pragma GCC visibility push(@var{visibility}) +@itemx #pragma GCC visibility pop +@cindex pragma, visibility + +This pragma allows the user to set the visibility for multiple +declarations without having to give each a visibility attribute +@xref{Function Attributes}, for more information about visibility and +the attribute syntax. + +In C++, @samp{#pragma GCC visibility} affects only namespace-scope +declarations. Class members and template specializations are not +affected; if you want to override the visibility for a particular +member or instantiation, you must use an attribute. + +@end table + +@node Unnamed Fields +@section Unnamed struct/union fields within structs/unions +@cindex struct +@cindex union + +For compatibility with other compilers, GCC allows you to define +a structure or union that contains, as fields, structures and unions +without names. For example: + +@smallexample +struct @{ + int a; + union @{ + int b; + float c; + @}; + int d; +@} foo; +@end smallexample + +In this example, the user would be able to access members of the unnamed +union with code like @samp{foo.b}. Note that only unnamed structs and +unions are allowed, you may not have, for example, an unnamed +@code{int}. + +You must never create such structures that cause ambiguous field definitions. +For example, this structure: + +@smallexample +struct @{ + int a; + struct @{ + int a; + @}; +@} foo; +@end smallexample + +It is ambiguous which @code{a} is being referred to with @samp{foo.a}. +Such constructs are not supported and must be avoided. In the future, +such constructs may be detected and treated as compilation errors. + +@opindex fms-extensions +Unless @option{-fms-extensions} is used, the unnamed field must be a +structure or union definition without a tag (for example, @samp{struct +@{ int a; @};}). If @option{-fms-extensions} is used, the field may +also be a definition with a tag such as @samp{struct foo @{ int a; +@};}, a reference to a previously defined structure or union such as +@samp{struct foo;}, or a reference to a @code{typedef} name for a +previously defined structure or union type. + +@node Thread-Local +@section Thread-Local Storage +@cindex Thread-Local Storage +@cindex @acronym{TLS} +@cindex __thread + +Thread-local storage (@acronym{TLS}) is a mechanism by which variables +are allocated such that there is one instance of the variable per extant +thread. The run-time model GCC uses to implement this originates +in the IA-64 processor-specific ABI, but has since been migrated +to other processors as well. It requires significant support from +the linker (@command{ld}), dynamic linker (@command{ld.so}), and +system libraries (@file{libc.so} and @file{libpthread.so}), so it +is not available everywhere. + +At the user level, the extension is visible with a new storage +class keyword: @code{__thread}. For example: + +@smallexample +__thread int i; +extern __thread struct state s; +static __thread char *p; +@end smallexample + +The @code{__thread} specifier may be used alone, with the @code{extern} +or @code{static} specifiers, but with no other storage class specifier. +When used with @code{extern} or @code{static}, @code{__thread} must appear +immediately after the other storage class specifier. + +The @code{__thread} specifier may be applied to any global, file-scoped +static, function-scoped static, or static data member of a class. It may +not be applied to block-scoped automatic or non-static data member. + +When the address-of operator is applied to a thread-local variable, it is +evaluated at run-time and returns the address of the current thread's +instance of that variable. An address so obtained may be used by any +thread. When a thread terminates, any pointers to thread-local variables +in that thread become invalid. + +No static initialization may refer to the address of a thread-local variable. + +In C++, if an initializer is present for a thread-local variable, it must +be a @var{constant-expression}, as defined in 5.19.2 of the ANSI/ISO C++ +standard. + +See @uref{http://people.redhat.com/drepper/tls.pdf, +ELF Handling For Thread-Local Storage} for a detailed explanation of +the four thread-local storage addressing models, and how the run-time +is expected to function. + +@menu +* C99 Thread-Local Edits:: +* C++98 Thread-Local Edits:: +@end menu + +@node C99 Thread-Local Edits +@subsection ISO/IEC 9899:1999 Edits for Thread-Local Storage + +The following are a set of changes to ISO/IEC 9899:1999 (aka C99) +that document the exact semantics of the language extension. + +@itemize @bullet +@item +@cite{5.1.2 Execution environments} + +Add new text after paragraph 1 + +@quotation +Within either execution environment, a @dfn{thread} is a flow of +control within a program. It is implementation defined whether +or not there may be more than one thread associated with a program. +It is implementation defined how threads beyond the first are +created, the name and type of the function called at thread +startup, and how threads may be terminated. However, objects +with thread storage duration shall be initialized before thread +startup. +@end quotation + +@item +@cite{6.2.4 Storage durations of objects} + +Add new text before paragraph 3 + +@quotation +An object whose identifier is declared with the storage-class +specifier @w{@code{__thread}} has @dfn{thread storage duration}. +Its lifetime is the entire execution of the thread, and its +stored value is initialized only once, prior to thread startup. +@end quotation + +@item +@cite{6.4.1 Keywords} + +Add @code{__thread}. + +@item +@cite{6.7.1 Storage-class specifiers} + +Add @code{__thread} to the list of storage class specifiers in +paragraph 1. + +Change paragraph 2 to + +@quotation +With the exception of @code{__thread}, at most one storage-class +specifier may be given [@dots{}]. The @code{__thread} specifier may +be used alone, or immediately following @code{extern} or +@code{static}. +@end quotation + +Add new text after paragraph 6 + +@quotation +The declaration of an identifier for a variable that has +block scope that specifies @code{__thread} shall also +specify either @code{extern} or @code{static}. + +The @code{__thread} specifier shall be used only with +variables. +@end quotation +@end itemize + +@node C++98 Thread-Local Edits +@subsection ISO/IEC 14882:1998 Edits for Thread-Local Storage + +The following are a set of changes to ISO/IEC 14882:1998 (aka C++98) +that document the exact semantics of the language extension. + +@itemize @bullet +@item +@b{[intro.execution]} + +New text after paragraph 4 + +@quotation +A @dfn{thread} is a flow of control within the abstract machine. +It is implementation defined whether or not there may be more than +one thread. +@end quotation + +New text after paragraph 7 + +@quotation +It is unspecified whether additional action must be taken to +ensure when and whether side effects are visible to other threads. +@end quotation + +@item +@b{[lex.key]} + +Add @code{__thread}. + +@item +@b{[basic.start.main]} + +Add after paragraph 5 + +@quotation +The thread that begins execution at the @code{main} function is called +the @dfn{main thread}. It is implementation defined how functions +beginning threads other than the main thread are designated or typed. +A function so designated, as well as the @code{main} function, is called +a @dfn{thread startup function}. It is implementation defined what +happens if a thread startup function returns. It is implementation +defined what happens to other threads when any thread calls @code{exit}. +@end quotation + +@item +@b{[basic.start.init]} + +Add after paragraph 4 + +@quotation +The storage for an object of thread storage duration shall be +statically initialized before the first statement of the thread startup +function. An object of thread storage duration shall not require +dynamic initialization. +@end quotation + +@item +@b{[basic.start.term]} + +Add after paragraph 3 + +@quotation +The type of an object with thread storage duration shall not have a +non-trivial destructor, nor shall it be an array type whose elements +(directly or indirectly) have non-trivial destructors. +@end quotation + +@item +@b{[basic.stc]} + +Add ``thread storage duration'' to the list in paragraph 1. + +Change paragraph 2 + +@quotation +Thread, static, and automatic storage durations are associated with +objects introduced by declarations [@dots{}]. +@end quotation + +Add @code{__thread} to the list of specifiers in paragraph 3. + +@item +@b{[basic.stc.thread]} + +New section before @b{[basic.stc.static]} + +@quotation +The keyword @code{__thread} applied to a non-local object gives the +object thread storage duration. + +A local variable or class data member declared both @code{static} +and @code{__thread} gives the variable or member thread storage +duration. +@end quotation + +@item +@b{[basic.stc.static]} + +Change paragraph 1 + +@quotation +All objects which have neither thread storage duration, dynamic +storage duration nor are local [@dots{}]. +@end quotation + +@item +@b{[dcl.stc]} + +Add @code{__thread} to the list in paragraph 1. + +Change paragraph 1 + +@quotation +With the exception of @code{__thread}, at most one +@var{storage-class-specifier} shall appear in a given +@var{decl-specifier-seq}. The @code{__thread} specifier may +be used alone, or immediately following the @code{extern} or +@code{static} specifiers. [@dots{}] +@end quotation + +Add after paragraph 5 + +@quotation +The @code{__thread} specifier can be applied only to the names of objects +and to anonymous unions. +@end quotation + +@item +@b{[class.mem]} + +Add after paragraph 6 + +@quotation +Non-@code{static} members shall not be @code{__thread}. +@end quotation +@end itemize + +@c APPLE LOCAL begin blocks 7205047 5811887 +@node Blocks +@section Blocks +@cindex Blocks +@cindex __block + +Blocks is a language feature that allows one to create anonymous +functions. The feature is also known as lambdas or closures in other +languages. The feature is controlled by @option{-fblocks}. +See @uref{http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html} for additional details. +@c APPLE LOCAL end blocks 7205047 5811887 + +@node C++ Extensions +@chapter Extensions to the C++ Language +@cindex extensions, C++ language +@cindex C++ language extensions + +The GNU compiler provides these extensions to the C++ language (and you +can also use most of the C language extensions in your C++ programs). If you +want to write code that checks whether these features are available, you can +test for the GNU compiler the same way as for C programs: check for a +predefined macro @code{__GNUC__}. You can also use @code{__GNUG__} to +test specifically for GNU C++ (@pxref{Common Predefined Macros,, +Predefined Macros,cpp,The GNU C Preprocessor}). + +@menu +* Volatiles:: What constitutes an access to a volatile object. +* Restricted Pointers:: C99 restricted pointers and references. +* Vague Linkage:: Where G++ puts inlines, vtables and such. +* C++ Interface:: You can use a single C++ header file for both + declarations and definitions. +* Template Instantiation:: Methods for ensuring that exactly one copy of + each needed template instantiation is emitted. +* Bound member functions:: You can extract a function pointer to the + method denoted by a @samp{->*} or @samp{.*} expression. +* C++ Attributes:: Variable, function, and type attributes for C++ only. +* Namespace Association:: Strong using-directives for namespace association. +* Java Exceptions:: Tweaking exception handling to work with Java. +* Deprecated Features:: Things will disappear from g++. +* Backwards Compatibility:: Compatibilities with earlier definitions of C++. +@end menu + +@node Volatiles +@section When is a Volatile Object Accessed? +@cindex accessing volatiles +@cindex volatile read +@cindex volatile write +@cindex volatile access + +Both the C and C++ standard have the concept of volatile objects. These +are normally accessed by pointers and used for accessing hardware. The +standards encourage compilers to refrain from optimizations concerning +accesses to volatile objects. The C standard leaves it implementation +defined as to what constitutes a volatile access. The C++ standard omits +to specify this, except to say that C++ should behave in a similar manner +to C with respect to volatiles, where possible. The minimum either +standard specifies is that at a sequence point all previous accesses to +volatile objects have stabilized and no subsequent accesses have +occurred. Thus an implementation is free to reorder and combine +volatile accesses which occur between sequence points, but cannot do so +for accesses across a sequence point. The use of volatiles does not +allow you to violate the restriction on updating objects multiple times +within a sequence point. + +@xref{Qualifiers implementation, , Volatile qualifier and the C compiler}. + +The behavior differs slightly between C and C++ in the non-obvious cases: + +@smallexample +volatile int *src = @var{somevalue}; +*src; +@end smallexample + +With C, such expressions are rvalues, and GCC interprets this either as a +read of the volatile object being pointed to or only as request to evaluate +the side-effects. The C++ standard specifies that such expressions do not +undergo lvalue to rvalue conversion, and that the type of the dereferenced +object may be incomplete. The C++ standard does not specify explicitly +that it is this lvalue to rvalue conversion which may be responsible for +causing an access. However, there is reason to believe that it is, +because otherwise certain simple expressions become undefined. However, +because it would surprise most programmers, G++ treats dereferencing a +pointer to volatile object of complete type when the value is unused as +GCC would do for an equivalent type in C. When the object has incomplete +type, G++ issues a warning; if you wish to force an error, you must +force a conversion to rvalue with, for instance, a static cast. + +When using a reference to volatile, G++ does not treat equivalent +expressions as accesses to volatiles, but instead issues a warning that +no volatile is accessed. The rationale for this is that otherwise it +becomes difficult to determine where volatile access occur, and not +possible to ignore the return value from functions returning volatile +references. Again, if you wish to force a read, cast the reference to +an rvalue. + +@node Restricted Pointers +@section Restricting Pointer Aliasing +@cindex restricted pointers +@cindex restricted references +@cindex restricted this pointer + +As with the C front end, G++ understands the C99 feature of restricted pointers, +specified with the @code{__restrict__}, or @code{__restrict} type +qualifier. Because you cannot compile C++ by specifying the @option{-std=c99} +language flag, @code{restrict} is not a keyword in C++. + +In addition to allowing restricted pointers, you can specify restricted +references, which indicate that the reference is not aliased in the local +context. + +@smallexample +void fn (int *__restrict__ rptr, int &__restrict__ rref) +@{ + /* @r{@dots{}} */ +@} +@end smallexample + +@noindent +In the body of @code{fn}, @var{rptr} points to an unaliased integer and +@var{rref} refers to a (different) unaliased integer. + +You may also specify whether a member function's @var{this} pointer is +unaliased by using @code{__restrict__} as a member function qualifier. + +@smallexample +void T::fn () __restrict__ +@{ + /* @r{@dots{}} */ +@} +@end smallexample + +@noindent +Within the body of @code{T::fn}, @var{this} will have the effective +definition @code{T *__restrict__ const this}. Notice that the +interpretation of a @code{__restrict__} member function qualifier is +different to that of @code{const} or @code{volatile} qualifier, in that it +is applied to the pointer rather than the object. This is consistent with +other compilers which implement restricted pointers. + +As with all outermost parameter qualifiers, @code{__restrict__} is +ignored in function definition matching. This means you only need to +specify @code{__restrict__} in a function definition, rather than +in a function prototype as well. + +@node Vague Linkage +@section Vague Linkage +@cindex vague linkage + +There are several constructs in C++ which require space in the object +file but are not clearly tied to a single translation unit. We say that +these constructs have ``vague linkage''. Typically such constructs are +emitted wherever they are needed, though sometimes we can be more +clever. + +@table @asis +@item Inline Functions +Inline functions are typically defined in a header file which can be +included in many different compilations. Hopefully they can usually be +inlined, but sometimes an out-of-line copy is necessary, if the address +of the function is taken or if inlining fails. In general, we emit an +out-of-line copy in all translation units where one is needed. As an +exception, we only emit inline virtual functions with the vtable, since +it will always require a copy. + +Local static variables and string constants used in an inline function +are also considered to have vague linkage, since they must be shared +between all inlined and out-of-line instances of the function. + +@item VTables +@cindex vtable +C++ virtual functions are implemented in most compilers using a lookup +table, known as a vtable. The vtable contains pointers to the virtual +functions provided by a class, and each object of the class contains a +pointer to its vtable (or vtables, in some multiple-inheritance +situations). If the class declares any non-inline, non-pure virtual +functions, the first one is chosen as the ``key method'' for the class, +and the vtable is only emitted in the translation unit where the key +method is defined. + +@emph{Note:} If the chosen key method is later defined as inline, the +vtable will still be emitted in every translation unit which defines it. +Make sure that any inline virtuals are declared inline in the class +body, even if they are not defined there. + +@item type_info objects +@cindex type_info +@cindex RTTI +C++ requires information about types to be written out in order to +implement @samp{dynamic_cast}, @samp{typeid} and exception handling. +For polymorphic classes (classes with virtual functions), the type_info +object is written out along with the vtable so that @samp{dynamic_cast} +can determine the dynamic type of a class object at runtime. For all +other types, we write out the type_info object when it is used: when +applying @samp{typeid} to an expression, throwing an object, or +referring to a type in a catch clause or exception specification. + +@item Template Instantiations +Most everything in this section also applies to template instantiations, +but there are other options as well. +@xref{Template Instantiation,,Where's the Template?}. + +@end table + +When used with GNU ld version 2.8 or later on an ELF system such as +GNU/Linux or Solaris 2, or on Microsoft Windows, duplicate copies of +these constructs will be discarded at link time. This is known as +COMDAT support. + +On targets that don't support COMDAT, but do support weak symbols, GCC +will use them. This way one copy will override all the others, but +the unused copies will still take up space in the executable. + +For targets which do not support either COMDAT or weak symbols, +most entities with vague linkage will be emitted as local symbols to +avoid duplicate definition errors from the linker. This will not happen +for local statics in inlines, however, as having multiple copies will +almost certainly break things. + +@xref{C++ Interface,,Declarations and Definitions in One Header}, for +another way to control placement of these constructs. + +@node C++ Interface +@section #pragma interface and implementation + +@cindex interface and implementation headers, C++ +@cindex C++ interface and implementation headers +@cindex pragmas, interface and implementation + +@code{#pragma interface} and @code{#pragma implementation} provide the +user with a way of explicitly directing the compiler to emit entities +with vague linkage (and debugging information) in a particular +translation unit. + +@emph{Note:} As of GCC 2.7.2, these @code{#pragma}s are not useful in +most cases, because of COMDAT support and the ``key method'' heuristic +mentioned in @ref{Vague Linkage}. Using them can actually cause your +program to grow due to unnecessary out-of-line copies of inline +functions. Currently (3.4) the only benefit of these +@code{#pragma}s is reduced duplication of debugging information, and +that should be addressed soon on DWARF 2 targets with the use of +COMDAT groups. + +@table @code +@item #pragma interface +@itemx #pragma interface "@var{subdir}/@var{objects}.h" +@kindex #pragma interface +Use this directive in @emph{header files} that define object classes, to save +space in most of the object files that use those classes. Normally, +local copies of certain information (backup copies of inline member +functions, debugging information, and the internal tables that implement +virtual functions) must be kept in each object file that includes class +definitions. You can use this pragma to avoid such duplication. When a +header file containing @samp{#pragma interface} is included in a +compilation, this auxiliary information will not be generated (unless +the main input source file itself uses @samp{#pragma implementation}). +Instead, the object files will contain references to be resolved at link +time. + +The second form of this directive is useful for the case where you have +multiple headers with the same name in different directories. If you +use this form, you must specify the same string to @samp{#pragma +implementation}. + +@item #pragma implementation +@itemx #pragma implementation "@var{objects}.h" +@kindex #pragma implementation +Use this pragma in a @emph{main input file}, when you want full output from +included header files to be generated (and made globally visible). The +included header file, in turn, should use @samp{#pragma interface}. +Backup copies of inline member functions, debugging information, and the +internal tables used to implement virtual functions are all generated in +implementation files. + +@cindex implied @code{#pragma implementation} +@cindex @code{#pragma implementation}, implied +@cindex naming convention, implementation headers +If you use @samp{#pragma implementation} with no argument, it applies to +an include file with the same basename@footnote{A file's @dfn{basename} +was the name stripped of all leading path information and of trailing +suffixes, such as @samp{.h} or @samp{.C} or @samp{.cc}.} as your source +file. For example, in @file{allclass.cc}, giving just +@samp{#pragma implementation} +by itself is equivalent to @samp{#pragma implementation "allclass.h"}. + +In versions of GNU C++ prior to 2.6.0 @file{allclass.h} was treated as +an implementation file whenever you would include it from +@file{allclass.cc} even if you never specified @samp{#pragma +implementation}. This was deemed to be more trouble than it was worth, +however, and disabled. + +Use the string argument if you want a single implementation file to +include code from multiple header files. (You must also use +@samp{#include} to include the header file; @samp{#pragma +implementation} only specifies how to use the file---it doesn't actually +include it.) + +There is no way to split up the contents of a single header file into +multiple implementation files. +@end table + +@cindex inlining and C++ pragmas +@cindex C++ pragmas, effect on inlining +@cindex pragmas in C++, effect on inlining +@samp{#pragma implementation} and @samp{#pragma interface} also have an +effect on function inlining. + +If you define a class in a header file marked with @samp{#pragma +interface}, the effect on an inline function defined in that class is +similar to an explicit @code{extern} declaration---the compiler emits +no code at all to define an independent version of the function. Its +definition is used only for inlining with its callers. + +@opindex fno-implement-inlines +Conversely, when you include the same header file in a main source file +that declares it as @samp{#pragma implementation}, the compiler emits +code for the function itself; this defines a version of the function +that can be found via pointers (or by callers compiled without +inlining). If all calls to the function can be inlined, you can avoid +emitting the function by compiling with @option{-fno-implement-inlines}. +If any calls were not inlined, you will get linker errors. + +@node Template Instantiation +@section Where's the Template? +@cindex template instantiation + +C++ templates are the first language feature to require more +intelligence from the environment than one usually finds on a UNIX +system. Somehow the compiler and linker have to make sure that each +template instance occurs exactly once in the executable if it is needed, +and not at all otherwise. There are two basic approaches to this +problem, which are referred to as the Borland model and the Cfront model. + +@table @asis +@item Borland model +Borland C++ solved the template instantiation problem by adding the code +equivalent of common blocks to their linker; the compiler emits template +instances in each translation unit that uses them, and the linker +collapses them together. The advantage of this model is that the linker +only has to consider the object files themselves; there is no external +complexity to worry about. This disadvantage is that compilation time +is increased because the template code is being compiled repeatedly. +Code written for this model tends to include definitions of all +templates in the header file, since they must be seen to be +instantiated. + +@item Cfront model +The AT&T C++ translator, Cfront, solved the template instantiation +problem by creating the notion of a template repository, an +automatically maintained place where template instances are stored. A +more modern version of the repository works as follows: As individual +object files are built, the compiler places any template definitions and +instantiations encountered in the repository. At link time, the link +wrapper adds in the objects in the repository and compiles any needed +instances that were not previously emitted. The advantages of this +model are more optimal compilation speed and the ability to use the +system linker; to implement the Borland model a compiler vendor also +needs to replace the linker. The disadvantages are vastly increased +complexity, and thus potential for error; for some code this can be +just as transparent, but in practice it can been very difficult to build +multiple programs in one directory and one program in multiple +directories. Code written for this model tends to separate definitions +of non-inline member templates into a separate file, which should be +compiled separately. +@end table + +When used with GNU ld version 2.8 or later on an ELF system such as +GNU/Linux or Solaris 2, or on Microsoft Windows, G++ supports the +Borland model. On other systems, G++ implements neither automatic +model. + +A future version of G++ will support a hybrid model whereby the compiler +will emit any instantiations for which the template definition is +included in the compile, and store template definitions and +instantiation context information into the object file for the rest. +The link wrapper will extract that information as necessary and invoke +the compiler to produce the remaining instantiations. The linker will +then combine duplicate instantiations. + +In the mean time, you have the following options for dealing with +template instantiations: + +@enumerate +@item +@opindex frepo +Compile your template-using code with @option{-frepo}. The compiler will +generate files with the extension @samp{.rpo} listing all of the +template instantiations used in the corresponding object files which +could be instantiated there; the link wrapper, @samp{collect2}, will +then update the @samp{.rpo} files to tell the compiler where to place +those instantiations and rebuild any affected object files. The +link-time overhead is negligible after the first pass, as the compiler +will continue to place the instantiations in the same files. + +This is your best option for application code written for the Borland +model, as it will just work. Code written for the Cfront model will +need to be modified so that the template definitions are available at +one or more points of instantiation; usually this is as simple as adding +@code{#include <tmethods.cc>} to the end of each template header. + +For library code, if you want the library to provide all of the template +instantiations it needs, just try to link all of its object files +together; the link will fail, but cause the instantiations to be +generated as a side effect. Be warned, however, that this may cause +conflicts if multiple libraries try to provide the same instantiations. +For greater control, use explicit instantiation as described in the next +option. + +@item +@opindex fno-implicit-templates +Compile your code with @option{-fno-implicit-templates} to disable the +implicit generation of template instances, and explicitly instantiate +all the ones you use. This approach requires more knowledge of exactly +which instances you need than do the others, but it's less +mysterious and allows greater control. You can scatter the explicit +instantiations throughout your program, perhaps putting them in the +translation units where the instances are used or the translation units +that define the templates themselves; you can put all of the explicit +instantiations you need into one big file; or you can create small files +like + +@smallexample +#include "Foo.h" +#include "Foo.cc" + +template class Foo<int>; +template ostream& operator << + (ostream&, const Foo<int>&); +@end smallexample + +for each of the instances you need, and create a template instantiation +library from those. + +If you are using Cfront-model code, you can probably get away with not +using @option{-fno-implicit-templates} when compiling files that don't +@samp{#include} the member template definitions. + +If you use one big file to do the instantiations, you may want to +compile it without @option{-fno-implicit-templates} so you get all of the +instances required by your explicit instantiations (but not by any +other files) without having to specify them as well. + +G++ has extended the template instantiation syntax given in the ISO +standard to allow forward declaration of explicit instantiations +(with @code{extern}), instantiation of the compiler support data for a +template class (i.e.@: the vtable) without instantiating any of its +members (with @code{inline}), and instantiation of only the static data +members of a template class, without the support data or member +functions (with (@code{static}): + +@smallexample +extern template int max (int, int); +inline template class Foo<int>; +static template class Foo<int>; +@end smallexample + +@item +Do nothing. Pretend G++ does implement automatic instantiation +management. Code written for the Borland model will work fine, but +each translation unit will contain instances of each of the templates it +uses. In a large program, this can lead to an unacceptable amount of code +duplication. +@end enumerate + +@node Bound member functions +@section Extracting the function pointer from a bound pointer to member function +@cindex pmf +@cindex pointer to member function +@cindex bound pointer to member function + +In C++, pointer to member functions (PMFs) are implemented using a wide +pointer of sorts to handle all the possible call mechanisms; the PMF +needs to store information about how to adjust the @samp{this} pointer, +and if the function pointed to is virtual, where to find the vtable, and +where in the vtable to look for the member function. If you are using +PMFs in an inner loop, you should really reconsider that decision. If +that is not an option, you can extract the pointer to the function that +would be called for a given object/PMF pair and call it directly inside +the inner loop, to save a bit of time. + +Note that you will still be paying the penalty for the call through a +function pointer; on most modern architectures, such a call defeats the +branch prediction features of the CPU@. This is also true of normal +virtual function calls. + +The syntax for this extension is + +@smallexample +extern A a; +extern int (A::*fp)(); +typedef int (*fptr)(A *); + +fptr p = (fptr)(a.*fp); +@end smallexample + +For PMF constants (i.e.@: expressions of the form @samp{&Klasse::Member}), +no object is needed to obtain the address of the function. They can be +converted to function pointers directly: + +@smallexample +fptr p1 = (fptr)(&A::foo); +@end smallexample + +@opindex Wno-pmf-conversions +You must specify @option{-Wno-pmf-conversions} to use this extension. + +@node C++ Attributes +@section C++-Specific Variable, Function, and Type Attributes + +Some attributes only make sense for C++ programs. + +@table @code +@item init_priority (@var{priority}) +@cindex init_priority attribute + + +In Standard C++, objects defined at namespace scope are guaranteed to be +initialized in an order in strict accordance with that of their definitions +@emph{in a given translation unit}. No guarantee is made for initializations +across translation units. However, GNU C++ allows users to control the +order of initialization of objects defined at namespace scope with the +@code{init_priority} attribute by specifying a relative @var{priority}, +a constant integral expression currently bounded between 101 and 65535 +inclusive. Lower numbers indicate a higher priority. + +In the following example, @code{A} would normally be created before +@code{B}, but the @code{init_priority} attribute has reversed that order: + +@smallexample +Some_Class A __attribute__ ((init_priority (2000))); +Some_Class B __attribute__ ((init_priority (543))); +@end smallexample + +@noindent +Note that the particular values of @var{priority} do not matter; only their +relative ordering. + +@item java_interface +@cindex java_interface attribute + +This type attribute informs C++ that the class is a Java interface. It may +only be applied to classes declared within an @code{extern "Java"} block. +Calls to methods declared in this interface will be dispatched using GCJ's +interface table mechanism, instead of regular virtual table dispatch. + +@end table + +See also @xref{Namespace Association}. + +@node Namespace Association +@section Namespace Association + +@strong{Caution:} The semantics of this extension are not fully +defined. Users should refrain from using this extension as its +semantics may change subtly over time. It is possible that this +extension will be removed in future versions of G++. + +A using-directive with @code{__attribute ((strong))} is stronger +than a normal using-directive in two ways: + +@itemize @bullet +@item +Templates from the used namespace can be specialized and explicitly +instantiated as though they were members of the using namespace. + +@item +The using namespace is considered an associated namespace of all +templates in the used namespace for purposes of argument-dependent +name lookup. +@end itemize + +The used namespace must be nested within the using namespace so that +normal unqualified lookup works properly. + +This is useful for composing a namespace transparently from +implementation namespaces. For example: + +@smallexample +namespace std @{ + namespace debug @{ + template <class T> struct A @{ @}; + @} + using namespace debug __attribute ((__strong__)); + template <> struct A<int> @{ @}; // @r{ok to specialize} + + template <class T> void f (A<T>); +@} + +int main() +@{ + f (std::A<float>()); // @r{lookup finds} std::f + f (std::A<int>()); +@} +@end smallexample + +@node Java Exceptions +@section Java Exceptions + +The Java language uses a slightly different exception handling model +from C++. Normally, GNU C++ will automatically detect when you are +writing C++ code that uses Java exceptions, and handle them +appropriately. However, if C++ code only needs to execute destructors +when Java exceptions are thrown through it, GCC will guess incorrectly. +Sample problematic code is: + +@smallexample + struct S @{ ~S(); @}; + extern void bar(); // @r{is written in Java, and may throw exceptions} + void foo() + @{ + S s; + bar(); + @} +@end smallexample + +@noindent +The usual effect of an incorrect guess is a link failure, complaining of +a missing routine called @samp{__gxx_personality_v0}. + +You can inform the compiler that Java exceptions are to be used in a +translation unit, irrespective of what it might think, by writing +@samp{@w{#pragma GCC java_exceptions}} at the head of the file. This +@samp{#pragma} must appear before any functions that throw or catch +exceptions, or run destructors when exceptions are thrown through them. + +You cannot mix Java and C++ exceptions in the same translation unit. It +is believed to be safe to throw a C++ exception from one file through +another file compiled for the Java exception model, or vice versa, but +there may be bugs in this area. + +@node Deprecated Features +@section Deprecated Features + +In the past, the GNU C++ compiler was extended to experiment with new +features, at a time when the C++ language was still evolving. Now that +the C++ standard is complete, some of those features are superseded by +superior alternatives. Using the old features might cause a warning in +some cases that the feature will be dropped in the future. In other +cases, the feature might be gone already. + +While the list below is not exhaustive, it documents some of the options +that are now deprecated: + +@table @code +@item -fexternal-templates +@itemx -falt-external-templates +These are two of the many ways for G++ to implement template +instantiation. @xref{Template Instantiation}. The C++ standard clearly +defines how template definitions have to be organized across +implementation units. G++ has an implicit instantiation mechanism that +should work just fine for standard-conforming code. + +@item -fstrict-prototype +@itemx -fno-strict-prototype +Previously it was possible to use an empty prototype parameter list to +indicate an unspecified number of parameters (like C), rather than no +parameters, as C++ demands. This feature has been removed, except where +it is required for backwards compatibility @xref{Backwards Compatibility}. +@end table + +G++ allows a virtual function returning @samp{void *} to be overridden +by one returning a different pointer type. This extension to the +covariant return type rules is now deprecated and will be removed from a +future version. + +The G++ minimum and maximum operators (@samp{<?} and @samp{>?}) and +their compound forms (@samp{<?=}) and @samp{>?=}) have been deprecated +@c APPLE LOCAL begin for-fsf-4_4 5482863 +and are now removed from G++. Code using these operators should be +modified to use @code{std::min} and @code{std::max} instead. + +@c APPLE LOCAL end for-fsf-4_4 5482863 +The named return value extension has been deprecated, and is now +removed from G++. + +The use of initializer lists with new expressions has been deprecated, +and is now removed from G++. + +Floating and complex non-type template parameters have been deprecated, +and are now removed from G++. + +The implicit typename extension has been deprecated and is now +removed from G++. + +The use of default arguments in function pointers, function typedefs +and other places where they are not permitted by the standard is +deprecated and will be removed from a future version of G++. + +G++ allows floating-point literals to appear in integral constant expressions, +e.g. @samp{ enum E @{ e = int(2.2 * 3.7) @} } +This extension is deprecated and will be removed from a future version. + +G++ allows static data members of const floating-point type to be declared +with an initializer in a class definition. The standard only allows +initializers for static members of const integral types and const +enumeration types so this extension has been deprecated and will be removed +from a future version. + +@node Backwards Compatibility +@section Backwards Compatibility +@cindex Backwards Compatibility +@cindex ARM [Annotated C++ Reference Manual] + +Now that there is a definitive ISO standard C++, G++ has a specification +to adhere to. The C++ language evolved over time, and features that +used to be acceptable in previous drafts of the standard, such as the ARM +[Annotated C++ Reference Manual], are no longer accepted. In order to allow +compilation of C++ written to such drafts, G++ contains some backwards +compatibilities. @emph{All such backwards compatibility features are +liable to disappear in future versions of G++.} They should be considered +deprecated @xref{Deprecated Features}. + +@table @code +@item For scope +If a variable is declared at for scope, it used to remain in scope until +the end of the scope which contained the for statement (rather than just +within the for scope). G++ retains this, but issues a warning, if such a +variable is accessed outside the for scope. + +@item Implicit C language +Old C system header files did not contain an @code{extern "C" @{@dots{}@}} +scope to set the language. On such systems, all header files are +implicitly scoped inside a C language scope. Also, an empty prototype +@code{()} will be treated as an unspecified number of arguments, rather +than no arguments, as C++ demands. +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/fragments.texi b/gcc-4.2.1-5666.3/gcc/doc/fragments.texi new file mode 100644 index 000000000..35fcad129 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/fragments.texi @@ -0,0 +1,220 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2003 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Fragments +@chapter Makefile Fragments +@cindex makefile fragment + +When you configure GCC using the @file{configure} script, it will +construct the file @file{Makefile} from the template file +@file{Makefile.in}. When it does this, it can incorporate makefile +fragments from the @file{config} directory. These are used to set +Makefile parameters that are not amenable to being calculated by +autoconf. The list of fragments to incorporate is set by +@file{config.gcc} (and occasionally @file{config.build} +and @file{config.host}); @xref{System Config}. + +Fragments are named either @file{t-@var{target}} or @file{x-@var{host}}, +depending on whether they are relevant to configuring GCC to produce +code for a particular target, or to configuring GCC to run on a +particular host. Here @var{target} and @var{host} are mnemonics +which usually have some relationship to the canonical system name, but +no formal connection. + +If these files do not exist, it means nothing needs to be added for a +given target or host. Most targets need a few @file{t-@var{target}} +fragments, but needing @file{x-@var{host}} fragments is rare. + +@menu +* Target Fragment:: Writing @file{t-@var{target}} files. +* Host Fragment:: Writing @file{x-@var{host}} files. +@end menu + +@node Target Fragment +@section Target Makefile Fragments +@cindex target makefile fragment +@cindex @file{t-@var{target}} + +Target makefile fragments can set these Makefile variables. + +@table @code +@findex LIBGCC2_CFLAGS +@item LIBGCC2_CFLAGS +Compiler flags to use when compiling @file{libgcc2.c}. + +@c APPLE LOCAL begin gcov 5573505 +@findex LIBGCC2_STATIC_CFLAGS +@item LIBGCC2_STATIC_CFLAGS +Compiler flags to use when compiling @file{libgcc2.c} for a non-shared library. +@c APPLE LOCAL end gcov 5573505 + +@findex LIB2FUNCS_EXTRA +@item LIB2FUNCS_EXTRA +A list of source file names to be compiled or assembled and inserted +into @file{libgcc.a}. + +@findex Floating Point Emulation +@item Floating Point Emulation +To have GCC include software floating point libraries in @file{libgcc.a} +define @code{FPBIT} and @code{DPBIT} along with a few rules as follows: +@smallexample +# We want fine grained libraries, so use the new code +# to build the floating point emulation libraries. +FPBIT = fp-bit.c +DPBIT = dp-bit.c + + +fp-bit.c: $(srcdir)/config/fp-bit.c + echo '#define FLOAT' > fp-bit.c + cat $(srcdir)/config/fp-bit.c >> fp-bit.c + +dp-bit.c: $(srcdir)/config/fp-bit.c + cat $(srcdir)/config/fp-bit.c > dp-bit.c +@end smallexample + +You may need to provide additional #defines at the beginning of @file{fp-bit.c} +and @file{dp-bit.c} to control target endianness and other options. + + +@findex CRTSTUFF_T_CFLAGS +@item CRTSTUFF_T_CFLAGS +Special flags used when compiling @file{crtstuff.c}. +@xref{Initialization}. + +@findex CRTSTUFF_T_CFLAGS_S +@item CRTSTUFF_T_CFLAGS_S +Special flags used when compiling @file{crtstuff.c} for shared +linking. Used if you use @file{crtbeginS.o} and @file{crtendS.o} +in @code{EXTRA-PARTS}. +@xref{Initialization}. + +@findex MULTILIB_OPTIONS +@item MULTILIB_OPTIONS +For some targets, invoking GCC in different ways produces objects +that can not be linked together. For example, for some targets GCC +produces both big and little endian code. For these targets, you must +arrange for multiple versions of @file{libgcc.a} to be compiled, one for +each set of incompatible options. When GCC invokes the linker, it +arranges to link in the right version of @file{libgcc.a}, based on +the command line options used. + +The @code{MULTILIB_OPTIONS} macro lists the set of options for which +special versions of @file{libgcc.a} must be built. Write options that +are mutually incompatible side by side, separated by a slash. Write +options that may be used together separated by a space. The build +procedure will build all combinations of compatible options. + +For example, if you set @code{MULTILIB_OPTIONS} to @samp{m68000/m68020 +msoft-float}, @file{Makefile} will build special versions of +@file{libgcc.a} using the following sets of options: @option{-m68000}, +@option{-m68020}, @option{-msoft-float}, @samp{-m68000 -msoft-float}, and +@samp{-m68020 -msoft-float}. + +@findex MULTILIB_DIRNAMES +@item MULTILIB_DIRNAMES +If @code{MULTILIB_OPTIONS} is used, this variable specifies the +directory names that should be used to hold the various libraries. +Write one element in @code{MULTILIB_DIRNAMES} for each element in +@code{MULTILIB_OPTIONS}. If @code{MULTILIB_DIRNAMES} is not used, the +default value will be @code{MULTILIB_OPTIONS}, with all slashes treated +as spaces. + +For example, if @code{MULTILIB_OPTIONS} is set to @samp{m68000/m68020 +msoft-float}, then the default value of @code{MULTILIB_DIRNAMES} is +@samp{m68000 m68020 msoft-float}. You may specify a different value if +you desire a different set of directory names. + +@findex MULTILIB_MATCHES +@item MULTILIB_MATCHES +Sometimes the same option may be written in two different ways. If an +option is listed in @code{MULTILIB_OPTIONS}, GCC needs to know about +any synonyms. In that case, set @code{MULTILIB_MATCHES} to a list of +items of the form @samp{option=option} to describe all relevant +synonyms. For example, @samp{m68000=mc68000 m68020=mc68020}. + +@findex MULTILIB_EXCEPTIONS +@item MULTILIB_EXCEPTIONS +Sometimes when there are multiple sets of @code{MULTILIB_OPTIONS} being +specified, there are combinations that should not be built. In that +case, set @code{MULTILIB_EXCEPTIONS} to be all of the switch exceptions +in shell case syntax that should not be built. + +For example the ARM processor cannot execute both hardware floating +point instructions and the reduced size THUMB instructions at the same +time, so there is no need to build libraries with both of these +options enabled. Therefore @code{MULTILIB_EXCEPTIONS} is set to: +@smallexample +*mthumb/*mhard-float* +@end smallexample + +@findex MULTILIB_EXTRA_OPTS +@item MULTILIB_EXTRA_OPTS +Sometimes it is desirable that when building multiple versions of +@file{libgcc.a} certain options should always be passed on to the +compiler. In that case, set @code{MULTILIB_EXTRA_OPTS} to be the list +of options to be used for all builds. If you set this, you should +probably set @code{CRTSTUFF_T_CFLAGS} to a dash followed by it. + +@findex NATIVE_SYSTEM_HEADER_DIR +@item NATIVE_SYSTEM_HEADER_DIR +If the default location for system headers is not @file{/usr/include}, +you must set this to the directory containing the headers. This value +should match the value of the @code{SYSTEM_INCLUDE_DIR} macro. + +@findex SPECS +@item SPECS +Unfortunately, setting @code{MULTILIB_EXTRA_OPTS} is not enough, since +it does not affect the build of target libraries, at least not the +build of the default multilib. One possible work-around is to use +@code{DRIVER_SELF_SPECS} to bring options from the @file{specs} file +as if they had been passed in the compiler driver command line. +However, you don't want to be adding these options after the toolchain +is installed, so you can instead tweak the @file{specs} file that will +be used during the toolchain build, while you still install the +original, built-in @file{specs}. The trick is to set @code{SPECS} to +some other filename (say @file{specs.install}), that will then be +created out of the built-in specs, and introduce a @file{Makefile} +rule to generate the @file{specs} file that's going to be used at +build time out of your @file{specs.install}. +@end table + +@node Host Fragment +@section Host Makefile Fragments +@cindex host makefile fragment +@cindex @file{x-@var{host}} + +The use of @file{x-@var{host}} fragments is discouraged. You should do +so only if there is no other mechanism to get the behavior desired. +Host fragments should never forcibly override variables set by the +configure script, as they may have been adjusted by the user. + +Variables provided for host fragments to set include: + +@table @code + +@item X_CFLAGS +@itemx X_CPPFLAGS +These are extra flags to pass to the C compiler and preprocessor, +respectively. They are used both when building GCC, and when compiling +things with the just-built GCC@. + +@item XCFLAGS +These are extra flags to use when building the compiler. They are not +used when compiling @file{libgcc.a}. However, they @emph{are} used when +recompiling the compiler with itself in later stages of a bootstrap. + +@item BOOT_LDFLAGS +Flags to be passed to the linker when recompiling the compiler with +itself in later stages of a bootstrap. You might need to use this if, +for instance, one of the front ends needs more text space than the +linker provides by default. + +@item EXTRA_PROGRAMS +A list of additional programs required to use the compiler on this host, +which should be compiled with GCC and installed alongside the front +ends. If you set this variable, you must also provide rules to build +the extra programs. + +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/frontends.texi b/gcc-4.2.1-5666.3/gcc/doc/frontends.texi new file mode 100644 index 000000000..68d3ba0b5 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/frontends.texi @@ -0,0 +1,63 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node G++ and GCC +@chapter Programming Languages Supported by GCC + +@cindex GCC +@cindex GNU Compiler Collection +@cindex GNU C Compiler +@cindex Ada +@cindex Fortran +@cindex Java +@cindex Objective-C +@cindex Objective-C++ +@cindex treelang +GCC stands for ``GNU Compiler Collection''. GCC is an integrated +distribution of compilers for several major programming languages. These +languages currently include C, C++, Objective-C, Objective-C++, Java, +Fortran, and Ada. + +The abbreviation @dfn{GCC} has multiple meanings in common use. The +current official meaning is ``GNU Compiler Collection'', which refers +generically to the complete suite of tools. The name historically stood +for ``GNU C Compiler'', and this usage is still common when the emphasis +is on compiling C programs. Finally, the name is also used when speaking +of the @dfn{language-independent} component of GCC: code shared among the +compilers for all supported languages. + +The language-independent component of GCC includes the majority of the +optimizers, as well as the ``back ends'' that generate machine code for +various processors. + +@cindex COBOL +@cindex Mercury +@cindex Pascal +The part of a compiler that is specific to a particular language is +called the ``front end''. In addition to the front ends that are +integrated components of GCC, there are several other front ends that +are maintained separately. These support languages such as Pascal, +Mercury, and COBOL@. To use these, they must be built together with +GCC proper. + +@cindex C++ +@cindex G++ +@cindex Ada +@cindex GNAT +Most of the compilers for languages other than C have their own names. +The C++ compiler is G++, the Ada compiler is GNAT, and so on. When we +talk about compiling one of those languages, we might refer to that +compiler by its own name, or as GCC@. Either is correct. + +@cindex compiler compared to C++ preprocessor +@cindex intermediate C version, nonexistent +@cindex C intermediate output, nonexistent +Historically, compilers for many languages, including C++ and Fortran, +have been implemented as ``preprocessors'' which emit another high +level language such as C@. None of the compilers included in GCC are +implemented this way; they all generate machine code directly. This +sort of preprocessor should not be confused with the @dfn{C +preprocessor}, which is an integral feature of the C, C++, Objective-C +and Objective-C++ languages. diff --git a/gcc-4.2.1-5666.3/gcc/doc/gcc.texi b/gcc-4.2.1-5666.3/gcc/doc/gcc.texi new file mode 100644 index 000000000..c98b4d799 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/gcc.texi @@ -0,0 +1,205 @@ +\input texinfo @c -*-texinfo-*- +@c %**start of header +@setfilename gcc.info +@c INTERNALS is used by md.texi to determine whether to include the +@c whole of that file, in the internals manual, or only the part +@c dealing with constraints, in the user manual. +@clear INTERNALS + +@c NOTE: checks/things to do: +@c +@c -have bob do a search in all seven files for "mew" (ideally --mew, +@c but i may have forgotten the occasional "--"..). +@c Just checked... all have `--'! Bob 22Jul96 +@c Use this to search: grep -n '\-\-mew' *.texi +@c -item/itemx, text after all (sub/sub)section titles, etc.. +@c -consider putting the lists of options on pp 17--> etc in columns or +@c some such. +@c -overfulls. do a search for "mew" in the files, and you will see +@c overfulls that i noted but could not deal with. +@c -have to add text: beginning of chapter 8 + +@c +@c anything else? --mew 10feb93 + +@include gcc-common.texi + +@settitle Using the GNU Compiler Collection (GCC) + +@c Create a separate index for command line options. +@defcodeindex op +@c Merge the standard indexes into a single one. +@syncodeindex fn cp +@syncodeindex vr cp +@syncodeindex ky cp +@syncodeindex pg cp +@syncodeindex tp cp + +@paragraphindent 1 + +@c %**end of header + +@copying +Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with the +Invariant Sections being ``GNU General Public License'' and ``Funding +Free Software'', the Front-Cover texts being (a) (see below), and with +the Back-Cover Texts being (b) (see below). A copy of the license is +included in the section entitled ``GNU Free Documentation License''. + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@end copying +@ifnottex +@dircategory Software development +@direntry +* gcc: (gcc). The GNU Compiler Collection. +@end direntry +This file documents the use of the GNU compilers. +@sp 1 +@insertcopying +@sp 1 +@end ifnottex + +@setchapternewpage odd +@titlepage +@title Using the GNU Compiler Collection +@versionsubtitle +@author Richard M. Stallman and the @sc{GCC} Developer Community +@page +@vskip 0pt plus 1filll +Published by: +@multitable @columnfractions 0.5 0.5 +@item GNU Press +@tab Website: www.gnupress.org +@item a division of the +@tab General: @tex press@@gnu.org @end tex +@item Free Software Foundation +@tab Orders: @tex sales@@gnu.org @end tex +@item 51 Franklin Street, Fifth Floor +@tab Tel 617-542-5942 +@item Boston, MA 02110-1301 USA +@tab Fax 617-542-2652 +@end multitable +@sp 2 +@ifset FSFPRINT +@c Update this ISBN when printing a new edition. +@acronym{ISBN} 1-882114-39-6 + +Cover art by Gary M. Torrisi. Cover design by Jonathan Richard. +@end ifset +@ifclear FSFPRINT +Last printed October 2003 for GCC 3.3.1.@* +Printed copies are available for $45 each. +@end ifclear +@sp 1 +@insertcopying +@end titlepage +@summarycontents +@contents +@page + +@node Top, G++ and GCC,, (DIR) +@top Introduction +@cindex introduction + +This manual documents how to use the GNU compilers, +as well as their features and incompatibilities, and how to report +bugs. It corresponds to GCC version @value{version-GCC}. +The internals of the GNU compilers, including how to port them to new +targets and some information about how to write front ends for new +languages, are documented in a separate manual. @xref{Top,, +Introduction, gccint, GNU Compiler Collection (GCC) Internals}. + +@menu +* G++ and GCC:: You can compile C or C++ programs. +* Standards:: Language standards supported by GCC. +* Invoking GCC:: Command options supported by @samp{gcc}. +* C Implementation:: How GCC implements the ISO C specification. +* C Extensions:: GNU extensions to the C language family. +* C++ Extensions:: GNU extensions to the C++ language. +* Objective-C:: GNU Objective-C runtime features. +* Compatibility:: Binary Compatibility +* Gcov:: @command{gcov}---a test coverage program. +* Trouble:: If you have trouble using GCC. +* Bugs:: How, why and where to report bugs. +* Service:: How to find suppliers of support for GCC. +* Contributing:: How to contribute to testing and developing GCC. + +* Funding:: How to help assure funding for free software. +* GNU Project:: The GNU Project and GNU/Linux. + +* Copying:: GNU General Public License says + how you can copy and share GCC. +@c APPLE LOCAL GPL compliance +* Source Code:: How to get the source code for this compiler. +* GNU Free Documentation License:: How you can copy and share this manual. +* Contributors:: People who have contributed to GCC. + +* Option Index:: Index to command line options. +* Keyword Index:: Index of concepts and symbol names. +@end menu + +@include frontends.texi +@include standards.texi +@include invoke.texi +@include implement-c.texi +@include extend.texi +@include objc.texi +@include compat.texi +@include gcov.texi +@include trouble.texi +@include bugreport.texi +@include service.texi +@include contribute.texi + +@include funding.texi +@include gnu.texi +@c APPLE LOCAL GPL compliance +@include sourcecode.texi +@include gpl.texi + +@c --------------------------------------------------------------------- +@c GFDL +@c --------------------------------------------------------------------- + +@include fdl.texi + +@include contrib.texi + +@c --------------------------------------------------------------------- +@c Indexes +@c --------------------------------------------------------------------- + +@node Option Index +@unnumbered Option Index + +GCC's command line options are indexed here without any initial @samp{-} +or @samp{--}. Where an option has both positive and negative forms +(such as @option{-f@var{option}} and @option{-fno-@var{option}}), +relevant entries in the manual are indexed under the most appropriate +form; it may sometimes be useful to look up both forms. + +@printindex op + +@node Keyword Index +@unnumbered Keyword Index + +@printindex cp + +@c --------------------------------------------------------------------- +@c Epilogue +@c --------------------------------------------------------------------- + +@bye diff --git a/gcc-4.2.1-5666.3/gcc/doc/gccint.texi b/gcc-4.2.1-5666.3/gcc/doc/gccint.texi new file mode 100644 index 000000000..9080ffdff --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/gccint.texi @@ -0,0 +1,189 @@ +\input texinfo @c -*-texinfo-*- +@c %**start of header +@setfilename gccint.info +@c INTERNALS is used by md.texi to determine whether to include the +@c whole of that file, in the internals manual, or only the part +@c dealing with constraints, in the user manual. +@set INTERNALS + +@c See miscellaneous notes in gcc.texi on checks/things to do. + +@include gcc-common.texi + +@settitle GNU Compiler Collection (GCC) Internals + +@c Create a separate index for command line options. +@defcodeindex op +@c Merge the standard indexes into a single one. +@syncodeindex fn cp +@syncodeindex vr cp +@syncodeindex ky cp +@syncodeindex pg cp +@syncodeindex tp cp + +@paragraphindent 1 + +@c %**end of header + +@copying +Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with the +Invariant Sections being ``GNU General Public License'' and ``Funding +Free Software'', the Front-Cover texts being (a) (see below), and with +the Back-Cover Texts being (b) (see below). A copy of the license is +included in the section entitled ``GNU Free Documentation License''. + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@end copying +@ifnottex +@dircategory Software development +@direntry +* gccint: (gccint). Internals of the GNU Compiler Collection. +@end direntry +This file documents the internals of the GNU compilers. +@sp 1 +@insertcopying +@sp 1 +@end ifnottex + +@setchapternewpage odd +@titlepage +@title GNU Compiler Collection Internals +@versionsubtitle +@author Richard M. Stallman and the @sc{GCC} Developer Community +@page +@vskip 0pt plus 1filll +@insertcopying +@end titlepage +@summarycontents +@contents +@page + +@node Top, Contributing,, (DIR) +@top Introduction +@cindex introduction + +This manual documents the internals of the GNU compilers, including +how to port them to new targets and some information about how to +write front ends for new languages. It corresponds to GCC version +@value{version-GCC}. The use of the GNU compilers is documented in a +separate manual. @xref{Top,, Introduction, gcc, Using the GNU +Compiler Collection (GCC)}. + +This manual is mainly a reference manual rather than a tutorial. It +discusses how to contribute to GCC (@pxref{Contributing}), the +characteristics of the machines supported by GCC as hosts and targets +(@pxref{Portability}), how GCC relates to the ABIs on such systems +(@pxref{Interface}), and the characteristics of the languages for +which GCC front ends are written (@pxref{Languages}). It then +describes the GCC source tree structure and build system, some of the +interfaces to GCC front ends, and how support for a target system is +implemented in GCC@. + +Additional tutorial information is linked to from +@uref{http://gcc.gnu.org/readings.html}. + +@menu +* Contributing:: How to contribute to testing and developing GCC. +* Portability:: Goals of GCC's portability features. +* Interface:: Function-call interface of GCC output. +* Libgcc:: Low-level runtime library used by GCC. +* Languages:: Languages for which GCC front ends are written. +* Source Tree:: GCC source tree structure and build system. +* Options:: Option specification files. +* Passes:: Order of passes, what they do, and what each file is for. +* Trees:: The source representation used by the C and C++ front ends. +* RTL:: The intermediate representation that most passes work on. +* Control Flow:: Maintaining and manipulating the control flow graph. +* Tree SSA:: Analysis and optimization of the tree representation. +* Loop Analysis and Representation:: Analysis and representation of loops +* Machine Desc:: How to write machine description instruction patterns. +* Target Macros:: How to write the machine description C macros and functions. +* Host Config:: Writing the @file{xm-@var{machine}.h} file. +* Fragments:: Writing the @file{t-@var{target}} and @file{x-@var{host}} files. +* Collect2:: How @code{collect2} works; how it finds @code{ld}. +* Header Dirs:: Understanding the standard header file directories. +* Type Information:: GCC's memory management; generating type information. + +* Funding:: How to help assure funding for free software. +* GNU Project:: The GNU Project and GNU/Linux. + +* Copying:: GNU General Public License says + how you can copy and share GCC. +* GNU Free Documentation License:: How you can copy and share this manual. +* Contributors:: People who have contributed to GCC. + +* Option Index:: Index to command line options. +* Concept Index:: Index of concepts and symbol names. +@end menu + +@include contribute.texi +@include portability.texi +@include interface.texi +@include libgcc.texi +@include languages.texi +@include sourcebuild.texi +@include options.texi +@include passes.texi +@include c-tree.texi +@include tree-ssa.texi +@include loop.texi +@include rtl.texi +@include cfg.texi +@include md.texi +@include tm.texi +@include hostconfig.texi +@include fragments.texi +@include collect2.texi +@include headerdirs.texi +@include gty.texi + +@include funding.texi +@include gnu.texi +@include gpl.texi + +@c --------------------------------------------------------------------- +@c GFDL +@c --------------------------------------------------------------------- + +@include fdl.texi + +@include contrib.texi + +@c --------------------------------------------------------------------- +@c Indexes +@c --------------------------------------------------------------------- + +@node Option Index +@unnumbered Option Index + +GCC's command line options are indexed here without any initial @samp{-} +or @samp{--}. Where an option has both positive and negative forms +(such as @option{-f@var{option}} and @option{-fno-@var{option}}), +relevant entries in the manual are indexed under the most appropriate +form; it may sometimes be useful to look up both forms. + +@printindex op + +@node Concept Index +@unnumbered Concept Index + +@printindex cp + +@c --------------------------------------------------------------------- +@c Epilogue +@c --------------------------------------------------------------------- + +@bye diff --git a/gcc-4.2.1-5666.3/gcc/doc/gcov.texi b/gcc-4.2.1-5666.3/gcc/doc/gcov.texi new file mode 100644 index 000000000..55c903c76 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/gcov.texi @@ -0,0 +1,573 @@ +@c Copyright (C) 1996, 1997, 1999, 2000, 2001, +@c 2002, 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@ignore +@c man begin COPYRIGHT +Copyright @copyright{} 1996, 1997, 1999, 2000, 2001, 2002, 2003, 2004, 2005 +Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with the +Invariant Sections being ``GNU General Public License'' and ``Funding +Free Software'', the Front-Cover texts being (a) (see below), and with +the Back-Cover Texts being (b) (see below). A copy of the license is +included in the gfdl(7) man page. + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@c man end +@c Set file name and title for the man page. +@setfilename gcov +@settitle coverage testing tool +@end ignore + +@node Gcov +@chapter @command{gcov}---a Test Coverage Program + +@command{gcov} is a tool you can use in conjunction with GCC to +test code coverage in your programs. + +@menu +* Gcov Intro:: Introduction to gcov. +* Invoking Gcov:: How to use gcov. +* Gcov and Optimization:: Using gcov with GCC optimization. +* Gcov Data Files:: The files used by gcov. +* Cross-profiling:: Data file relocation. +@end menu + +@node Gcov Intro +@section Introduction to @command{gcov} +@c man begin DESCRIPTION + +@command{gcov} is a test coverage program. Use it in concert with GCC +to analyze your programs to help create more efficient, faster running +code and to discover untested parts of your program. You can use +@command{gcov} as a profiling tool to help discover where your +optimization efforts will best affect your code. You can also use +@command{gcov} along with the other profiling tool, @command{gprof}, to +assess which parts of your code use the greatest amount of computing +time. + +Profiling tools help you analyze your code's performance. Using a +profiler such as @command{gcov} or @command{gprof}, you can find out some +basic performance statistics, such as: + +@itemize @bullet +@item +how often each line of code executes + +@item +what lines of code are actually executed + +@item +how much computing time each section of code uses +@end itemize + +Once you know these things about how your code works when compiled, you +can look at each module to see which modules should be optimized. +@command{gcov} helps you determine where to work on optimization. + +Software developers also use coverage testing in concert with +testsuites, to make sure software is actually good enough for a release. +Testsuites can verify that a program works as expected; a coverage +program tests to see how much of the program is exercised by the +testsuite. Developers can then determine what kinds of test cases need +to be added to the testsuites to create both better testing and a better +final product. + +You should compile your code without optimization if you plan to use +@command{gcov} because the optimization, by combining some lines of code +into one function, may not give you as much information as you need to +look for `hot spots' where the code is using a great deal of computer +time. Likewise, because @command{gcov} accumulates statistics by line (at +the lowest resolution), it works best with a programming style that +places only one statement on each line. If you use complicated macros +that expand to loops or to other control structures, the statistics are +less helpful---they only report on the line where the macro call +appears. If your complex macros behave like functions, you can replace +them with inline functions to solve this problem. + +@command{gcov} creates a logfile called @file{@var{sourcefile}.gcov} which +indicates how many times each line of a source file @file{@var{sourcefile}.c} +has executed. You can use these logfiles along with @command{gprof} to aid +in fine-tuning the performance of your programs. @command{gprof} gives +timing information you can use along with the information you get from +@command{gcov}. + +@command{gcov} works only on code compiled with GCC@. It is not +compatible with any other profiling or test coverage mechanism. + +@c man end + +@node Invoking Gcov +@section Invoking @command{gcov} + +@smallexample +gcov @r{[}@var{options}@r{]} @var{sourcefile} +@end smallexample + +@command{gcov} accepts the following options: + +@ignore +@c man begin SYNOPSIS +gcov [@option{-v}|@option{--version}] [@option{-h}|@option{--help}] + [@option{-a}|@option{--all-blocks}] + [@option{-b}|@option{--branch-probabilities}] + [@option{-c}|@option{--branch-counts}] + [@option{-n}|@option{--no-output}] + [@option{-l}|@option{--long-file-names}] + [@option{-p}|@option{--preserve-paths}] + [@option{-f}|@option{--function-summaries}] + [@option{-o}|@option{--object-directory} @var{directory|file}] @var{sourcefile} + [@option{-u}|@option{--unconditional-branches}] +@c man end +@c man begin SEEALSO +gpl(7), gfdl(7), fsf-funding(7), gcc(1) and the Info entry for @file{gcc}. +@c man end +@end ignore + +@c man begin OPTIONS +@table @gcctabopt +@item -h +@itemx --help +Display help about using @command{gcov} (on the standard output), and +exit without doing any further processing. + +@item -v +@itemx --version +Display the @command{gcov} version number (on the standard output), +and exit without doing any further processing. + +@item -a +@itemx --all-blocks +Write individual execution counts for every basic block. Normally gcov +outputs execution counts only for the main blocks of a line. With this +option you can determine if blocks within a single line are not being +executed. + +@item -b +@itemx --branch-probabilities +Write branch frequencies to the output file, and write branch summary +info to the standard output. This option allows you to see how often +each branch in your program was taken. Unconditional branches will not +be shown, unless the @option{-u} option is given. + +@item -c +@itemx --branch-counts +Write branch frequencies as the number of branches taken, rather than +the percentage of branches taken. + +@item -n +@itemx --no-output +Do not create the @command{gcov} output file. + +@item -l +@itemx --long-file-names +Create long file names for included source files. For example, if the +header file @file{x.h} contains code, and was included in the file +@file{a.c}, then running @command{gcov} on the file @file{a.c} will produce +an output file called @file{a.c##x.h.gcov} instead of @file{x.h.gcov}. +This can be useful if @file{x.h} is included in multiple source +files. If you use the @samp{-p} option, both the including and +included file names will be complete path names. + +@item -p +@itemx --preserve-paths +Preserve complete path information in the names of generated +@file{.gcov} files. Without this option, just the filename component is +used. With this option, all directories are used, with @samp{/} characters +translated to @samp{#} characters, @file{.} directory components +removed and @file{..} +components renamed to @samp{^}. This is useful if sourcefiles are in several +different directories. It also affects the @samp{-l} option. + +@item -f +@itemx --function-summaries +Output summaries for each function in addition to the file level summary. + +@item -o @var{directory|file} +@itemx --object-directory @var{directory} +@itemx --object-file @var{file} +Specify either the directory containing the gcov data files, or the +object path name. The @file{.gcno}, and +@file{.gcda} data files are searched for using this option. If a directory +is specified, the data files are in that directory and named after the +source file name, without its extension. If a file is specified here, +the data files are named after that file, without its extension. If this +option is not supplied, it defaults to the current directory. + +@item -u +@itemx --unconditional-branches +When branch probabilities are given, include those of unconditional branches. +Unconditional branches are normally not interesting. + +@end table + +@command{gcov} should be run with the current directory the same as that +when you invoked the compiler. Otherwise it will not be able to locate +the source files. @command{gcov} produces files called +@file{@var{mangledname}.gcov} in the current directory. These contain +the coverage information of the source file they correspond to. +One @file{.gcov} file is produced for each source file containing code, +which was compiled to produce the data files. The @var{mangledname} part +of the output file name is usually simply the source file name, but can +be something more complicated if the @samp{-l} or @samp{-p} options are +given. Refer to those options for details. + +The @file{.gcov} files contain the @samp{:} separated fields along with +program source code. The format is + +@smallexample +@var{execution_count}:@var{line_number}:@var{source line text} +@end smallexample + +Additional block information may succeed each line, when requested by +command line option. The @var{execution_count} is @samp{-} for lines +containing no code and @samp{#####} for lines which were never executed. +Some lines of information at the start have @var{line_number} of zero. + +The preamble lines are of the form + +@smallexample +-:0:@var{tag}:@var{value} +@end smallexample + +The ordering and number of these preamble lines will be augmented as +@command{gcov} development progresses --- do not rely on them remaining +unchanged. Use @var{tag} to locate a particular preamble line. + +The additional block information is of the form + +@smallexample +@var{tag} @var{information} +@end smallexample + +The @var{information} is human readable, but designed to be simple +enough for machine parsing too. + +When printing percentages, 0% and 100% are only printed when the values +are @emph{exactly} 0% and 100% respectively. Other values which would +conventionally be rounded to 0% or 100% are instead printed as the +nearest non-boundary value. + +When using @command{gcov}, you must first compile your program with two +special GCC options: @samp{-fprofile-arcs -ftest-coverage}. +This tells the compiler to generate additional information needed by +gcov (basically a flow graph of the program) and also includes +additional code in the object files for generating the extra profiling +information needed by gcov. These additional files are placed in the +directory where the object file is located. + +Running the program will cause profile output to be generated. For each +source file compiled with @option{-fprofile-arcs}, an accompanying +@file{.gcda} file will be placed in the object file directory. + +Running @command{gcov} with your program's source file names as arguments +will now produce a listing of the code along with frequency of execution +for each line. For example, if your program is called @file{tmp.c}, this +is what you see when you use the basic @command{gcov} facility: + +@smallexample +$ gcc -fprofile-arcs -ftest-coverage tmp.c +$ a.out +$ gcov tmp.c +90.00% of 10 source lines executed in file tmp.c +Creating tmp.c.gcov. +@end smallexample + +The file @file{tmp.c.gcov} contains output from @command{gcov}. +Here is a sample: + +@smallexample + -: 0:Source:tmp.c + -: 0:Graph:tmp.gcno + -: 0:Data:tmp.gcda + -: 0:Runs:1 + -: 0:Programs:1 + -: 1:#include <stdio.h> + -: 2: + -: 3:int main (void) + 1: 4:@{ + 1: 5: int i, total; + -: 6: + 1: 7: total = 0; + -: 8: + 11: 9: for (i = 0; i < 10; i++) + 10: 10: total += i; + -: 11: + 1: 12: if (total != 45) + #####: 13: printf ("Failure\n"); + -: 14: else + 1: 15: printf ("Success\n"); + 1: 16: return 0; + -: 17:@} +@end smallexample + +When you use the @option{-a} option, you will get individual block +counts, and the output looks like this: + +@smallexample + -: 0:Source:tmp.c + -: 0:Graph:tmp.gcno + -: 0:Data:tmp.gcda + -: 0:Runs:1 + -: 0:Programs:1 + -: 1:#include <stdio.h> + -: 2: + -: 3:int main (void) + 1: 4:@{ + 1: 4-block 0 + 1: 5: int i, total; + -: 6: + 1: 7: total = 0; + -: 8: + 11: 9: for (i = 0; i < 10; i++) + 11: 9-block 0 + 10: 10: total += i; + 10: 10-block 0 + -: 11: + 1: 12: if (total != 45) + 1: 12-block 0 + #####: 13: printf ("Failure\n"); + $$$$$: 13-block 0 + -: 14: else + 1: 15: printf ("Success\n"); + 1: 15-block 0 + 1: 16: return 0; + 1: 16-block 0 + -: 17:@} +@end smallexample + +In this mode, each basic block is only shown on one line -- the last +line of the block. A multi-line block will only contribute to the +execution count of that last line, and other lines will not be shown +to contain code, unless previous blocks end on those lines. +The total execution count of a line is shown and subsequent lines show +the execution counts for individual blocks that end on that line. After each +block, the branch and call counts of the block will be shown, if the +@option{-b} option is given. + +Because of the way GCC instruments calls, a call count can be shown +after a line with no individual blocks. +As you can see, line 13 contains a basic block that was not executed. + +@need 450 +When you use the @option{-b} option, your output looks like this: + +@smallexample +$ gcov -b tmp.c +90.00% of 10 source lines executed in file tmp.c +80.00% of 5 branches executed in file tmp.c +80.00% of 5 branches taken at least once in file tmp.c +50.00% of 2 calls executed in file tmp.c +Creating tmp.c.gcov. +@end smallexample + +Here is a sample of a resulting @file{tmp.c.gcov} file: + +@smallexample + -: 0:Source:tmp.c + -: 0:Graph:tmp.gcno + -: 0:Data:tmp.gcda + -: 0:Runs:1 + -: 0:Programs:1 + -: 1:#include <stdio.h> + -: 2: + -: 3:int main (void) +function main called 1 returned 1 blocks executed 75% + 1: 4:@{ + 1: 5: int i, total; + -: 6: + 1: 7: total = 0; + -: 8: + 11: 9: for (i = 0; i < 10; i++) +branch 0 taken 91% (fallthrough) +branch 1 taken 9% + 10: 10: total += i; + -: 11: + 1: 12: if (total != 45) +branch 0 taken 0% (fallthrough) +branch 1 taken 100% + #####: 13: printf ("Failure\n"); +call 0 never executed + -: 14: else + 1: 15: printf ("Success\n"); +call 0 called 1 returned 100% + 1: 16: return 0; + -: 17:@} +@end smallexample + +For each function, a line is printed showing how many times the function +is called, how many times it returns and what percentage of the +function's blocks were executed. + +For each basic block, a line is printed after the last line of the basic +block describing the branch or call that ends the basic block. There can +be multiple branches and calls listed for a single source line if there +are multiple basic blocks that end on that line. In this case, the +branches and calls are each given a number. There is no simple way to map +these branches and calls back to source constructs. In general, though, +the lowest numbered branch or call will correspond to the leftmost construct +on the source line. + +For a branch, if it was executed at least once, then a percentage +indicating the number of times the branch was taken divided by the +number of times the branch was executed will be printed. Otherwise, the +message ``never executed'' is printed. + +For a call, if it was executed at least once, then a percentage +indicating the number of times the call returned divided by the number +of times the call was executed will be printed. This will usually be +100%, but may be less for functions that call @code{exit} or @code{longjmp}, +and thus may not return every time they are called. + +The execution counts are cumulative. If the example program were +executed again without removing the @file{.gcda} file, the count for the +number of times each line in the source was executed would be added to +the results of the previous run(s). This is potentially useful in +several ways. For example, it could be used to accumulate data over a +number of program runs as part of a test verification suite, or to +provide more accurate long-term information over a large number of +program runs. + +The data in the @file{.gcda} files is saved immediately before the program +exits. For each source file compiled with @option{-fprofile-arcs}, the +profiling code first attempts to read in an existing @file{.gcda} file; if +the file doesn't match the executable (differing number of basic block +counts) it will ignore the contents of the file. It then adds in the +new execution counts and finally writes the data to the file. + +@node Gcov and Optimization +@section Using @command{gcov} with GCC Optimization + +If you plan to use @command{gcov} to help optimize your code, you must +first compile your program with two special GCC options: +@samp{-fprofile-arcs -ftest-coverage}. Aside from that, you can use any +other GCC options; but if you want to prove that every single line +in your program was executed, you should not compile with optimization +at the same time. On some machines the optimizer can eliminate some +simple code lines by combining them with other lines. For example, code +like this: + +@smallexample +if (a != b) + c = 1; +else + c = 0; +@end smallexample + +@noindent +can be compiled into one instruction on some machines. In this case, +there is no way for @command{gcov} to calculate separate execution counts +for each line because there isn't separate code for each line. Hence +the @command{gcov} output looks like this if you compiled the program with +optimization: + +@smallexample + 100: 12:if (a != b) + 100: 13: c = 1; + 100: 14:else + 100: 15: c = 0; +@end smallexample + +The output shows that this block of code, combined by optimization, +executed 100 times. In one sense this result is correct, because there +was only one instruction representing all four of these lines. However, +the output does not indicate how many times the result was 0 and how +many times the result was 1. + +Inlineable functions can create unexpected line counts. Line counts are +shown for the source code of the inlineable function, but what is shown +depends on where the function is inlined, or if it is not inlined at all. + +If the function is not inlined, the compiler must emit an out of line +copy of the function, in any object file that needs it. If +@file{fileA.o} and @file{fileB.o} both contain out of line bodies of a +particular inlineable function, they will also both contain coverage +counts for that function. When @file{fileA.o} and @file{fileB.o} are +linked together, the linker will, on many systems, select one of those +out of line bodies for all calls to that function, and remove or ignore +the other. Unfortunately, it will not remove the coverage counters for +the unused function body. Hence when instrumented, all but one use of +that function will show zero counts. + +If the function is inlined in several places, the block structure in +each location might not be the same. For instance, a condition might +now be calculable at compile time in some instances. Because the +coverage of all the uses of the inline function will be shown for the +same source lines, the line counts themselves might seem inconsistent. + +@c man end + +@node Gcov Data Files +@section Brief description of @command{gcov} data files + +@command{gcov} uses two files for profiling. The names of these files +are derived from the original @emph{object} file by substituting the +file suffix with either @file{.gcno}, or @file{.gcda}. All of these files +are placed in the same directory as the object file, and contain data +stored in a platform-independent format. + +The @file{.gcno} file is generated when the source file is compiled with +the GCC @option{-ftest-coverage} option. It contains information to +reconstruct the basic block graphs and assign source line numbers to +blocks. + +The @file{.gcda} file is generated when a program containing object files +built with the GCC @option{-fprofile-arcs} option is executed. A +separate @file{.gcda} file is created for each object file compiled with +this option. It contains arc transition counts, and some summary +information. + +The full details of the file format is specified in @file{gcov-io.h}, +and functions provided in that header file should be used to access the +coverage files. + +@node Cross-profiling +@section Data file relocation to support cross-profiling + +Running the program will cause profile output to be generated. For each +source file compiled with @option{-fprofile-arcs}, an accompanying @file{.gcda} +file will be placed in the object file directory. That implicitly requires +running the program on the same system as it was built or having the same +absolute directory structure on the target system. The program will try +to create the needed directory structure, if it is not already present. + +To support cross-profiling, a program compiled with @option{-fprofile-arcs} +can relocate the data files based on two environment variables: + +@itemize @bullet +@item +GCOV_PREFIX contains the prefix to add to the absolute paths +in the object file. Prefix must be absolute as well, otherwise its +value is ignored. The default is no prefix. + +@item +GCOV_PREFIX_STRIP indicates the how many initial directory names to strip off +the hardwired absolute paths. Default value is 0. + +@emph{Note:} GCOV_PREFIX_STRIP has no effect if GCOV_PREFIX is undefined, empty +or non-absolute. +@end itemize + +For example, if the object file @file{/user/build/foo.o} was built with +@option{-fprofile-arcs}, the final executable will try to create the data file +@file{/user/build/foo.gcda} when running on the target system. This will +fail if the corresponding directory does not exist and it is unable to create +it. This can be overcome by, for example, setting the environment as +@samp{GCOV_PREFIX=/target/run} and @samp{GCOV_PREFIX_STRIP=1}. Such a +setting will name the data file @file{/target/run/build/foo.gcda}. + +You must move the data files to the expected directory tree in order to +use them for profile directed optimizations (@option{--use-profile}), or to +use the @command{gcov} tool. diff --git a/gcc-4.2.1-5666.3/gcc/doc/gnu.texi b/gcc-4.2.1-5666.3/gcc/doc/gnu.texi new file mode 100644 index 000000000..641fe3072 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/gnu.texi @@ -0,0 +1,20 @@ +@c Copyright (C) 2001 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node GNU Project +@unnumbered The GNU Project and GNU/Linux + +The GNU Project was launched in 1984 to develop a complete Unix-like +operating system which is free software: the GNU system. (GNU is a +recursive acronym for ``GNU's Not Unix''; it is pronounced +``guh-NEW''@.) Variants of the GNU operating system, which use the +kernel Linux, are now widely used; though these systems are often +referred to as ``Linux'', they are more accurately called GNU/Linux +systems. + +For more information, see: +@smallexample +@uref{http://www.gnu.org/} +@uref{http://www.gnu.org/gnu/linux-and-gnu.html} +@end smallexample diff --git a/gcc-4.2.1-5666.3/gcc/doc/gty.texi b/gcc-4.2.1-5666.3/gcc/doc/gty.texi new file mode 100644 index 000000000..d997d1edc --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/gty.texi @@ -0,0 +1,436 @@ +@c Copyright (C) 2002, 2003, 2004 +@c Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Type Information +@chapter Memory Management and Type Information +@cindex GGC +@findex GTY + +GCC uses some fairly sophisticated memory management techniques, which +involve determining information about GCC's data structures from GCC's +source code and using this information to perform garbage collection and +implement precompiled headers. + +A full C parser would be too complicated for this task, so a limited +subset of C is interpreted and special markers are used to determine +what parts of the source to look at. All @code{struct} and +@code{union} declarations that define data structures that are +allocated under control of the garbage collector must be marked. All +global variables that hold pointers to garbage-collected memory must +also be marked. Finally, all global variables that need to be saved +and restored by a precompiled header must be marked. (The precompiled +header mechanism can only save static variables if they're scalar. +Complex data structures must be allocated in garbage-collected memory +to be saved in a precompiled header.) + +The full format of a marker is +@smallexample +GTY (([@var{option}] [(@var{param})], [@var{option}] [(@var{param})] @dots{})) +@end smallexample +@noindent +but in most cases no options are needed. The outer double parentheses +are still necessary, though: @code{GTY(())}. Markers can appear: + +@itemize @bullet +@item +In a structure definition, before the open brace; +@item +In a global variable declaration, after the keyword @code{static} or +@code{extern}; and +@item +In a structure field definition, before the name of the field. +@end itemize + +Here are some examples of marking simple data structures and globals. + +@smallexample +struct @var{tag} GTY(()) +@{ + @var{fields}@dots{} +@}; + +typedef struct @var{tag} GTY(()) +@{ + @var{fields}@dots{} +@} *@var{typename}; + +static GTY(()) struct @var{tag} *@var{list}; /* @r{points to GC memory} */ +static GTY(()) int @var{counter}; /* @r{save counter in a PCH} */ +@end smallexample + +The parser understands simple typedefs such as +@code{typedef struct @var{tag} *@var{name};} and +@code{typedef int @var{name};}. +These don't need to be marked. + +@menu +* GTY Options:: What goes inside a @code{GTY(())}. +* GGC Roots:: Making global variables GGC roots. +* Files:: How the generated files work. +@end menu + +@node GTY Options +@section The Inside of a @code{GTY(())} + +Sometimes the C code is not enough to fully describe the type +structure. Extra information can be provided with @code{GTY} options +and additional markers. Some options take a parameter, which may be +either a string or a type name, depending on the parameter. If an +option takes no parameter, it is acceptable either to omit the +parameter entirely, or to provide an empty string as a parameter. For +example, @code{@w{GTY ((skip))}} and @code{@w{GTY ((skip ("")))}} are +equivalent. + +When the parameter is a string, often it is a fragment of C code. Four +special escapes may be used in these strings, to refer to pieces of +the data structure being marked: + +@cindex % in GTY option +@table @code +@item %h +The current structure. +@item %1 +The structure that immediately contains the current structure. +@item %0 +The outermost structure that contains the current structure. +@item %a +A partial expression of the form @code{[i1][i2]...} that indexes +the array item currently being marked. +@end table + +For instance, suppose that you have a structure of the form +@smallexample +struct A @{ + ... +@}; +struct B @{ + struct A foo[12]; +@}; +@end smallexample +@noindent +and @code{b} is a variable of type @code{struct B}. When marking +@samp{b.foo[11]}, @code{%h} would expand to @samp{b.foo[11]}, +@code{%0} and @code{%1} would both expand to @samp{b}, and @code{%a} +would expand to @samp{[11]}. + +As in ordinary C, adjacent strings will be concatenated; this is +helpful when you have a complicated expression. +@smallexample +@group +GTY ((chain_next ("TREE_CODE (&%h.generic) == INTEGER_TYPE" + " ? TYPE_NEXT_VARIANT (&%h.generic)" + " : TREE_CHAIN (&%h.generic)"))) +@end group +@end smallexample + +The available options are: + +@table @code +@findex length +@item length ("@var{expression}") + +There are two places the type machinery will need to be explicitly told +the length of an array. The first case is when a structure ends in a +variable-length array, like this: +@smallexample +struct rtvec_def GTY(()) @{ + int num_elem; /* @r{number of elements} */ + rtx GTY ((length ("%h.num_elem"))) elem[1]; +@}; +@end smallexample + +In this case, the @code{length} option is used to override the specified +array length (which should usually be @code{1}). The parameter of the +option is a fragment of C code that calculates the length. + +The second case is when a structure or a global variable contains a +pointer to an array, like this: +@smallexample +tree * + GTY ((length ("%h.regno_pointer_align_length"))) regno_decl; +@end smallexample +In this case, @code{regno_decl} has been allocated by writing something like +@smallexample + x->regno_decl = + ggc_alloc (x->regno_pointer_align_length * sizeof (tree)); +@end smallexample +and the @code{length} provides the length of the field. + +This second use of @code{length} also works on global variables, like: +@verbatim + static GTY((length ("reg_base_value_size"))) + rtx *reg_base_value; +@end verbatim + +@findex skip +@item skip + +If @code{skip} is applied to a field, the type machinery will ignore it. +This is somewhat dangerous; the only safe use is in a union when one +field really isn't ever used. + +@findex desc +@findex tag +@findex default +@item desc ("@var{expression}") +@itemx tag ("@var{constant}") +@itemx default + +The type machinery needs to be told which field of a @code{union} is +currently active. This is done by giving each field a constant +@code{tag} value, and then specifying a discriminator using @code{desc}. +The value of the expression given by @code{desc} is compared against +each @code{tag} value, each of which should be different. If no +@code{tag} is matched, the field marked with @code{default} is used if +there is one, otherwise no field in the union will be marked. + +In the @code{desc} option, the ``current structure'' is the union that +it discriminates. Use @code{%1} to mean the structure containing it. +There are no escapes available to the @code{tag} option, since it is a +constant. + +For example, +@smallexample +struct tree_binding GTY(()) +@{ + struct tree_common common; + union tree_binding_u @{ + tree GTY ((tag ("0"))) scope; + struct cp_binding_level * GTY ((tag ("1"))) level; + @} GTY ((desc ("BINDING_HAS_LEVEL_P ((tree)&%0)"))) xscope; + tree value; +@}; +@end smallexample + +In this example, the value of BINDING_HAS_LEVEL_P when applied to a +@code{struct tree_binding *} is presumed to be 0 or 1. If 1, the type +mechanism will treat the field @code{level} as being present and if 0, +will treat the field @code{scope} as being present. + +@findex param_is +@findex use_param +@item param_is (@var{type}) +@itemx use_param + +Sometimes it's convenient to define some data structure to work on +generic pointers (that is, @code{PTR}) and then use it with a specific +type. @code{param_is} specifies the real type pointed to, and +@code{use_param} says where in the generic data structure that type +should be put. + +For instance, to have a @code{htab_t} that points to trees, one would +write the definition of @code{htab_t} like this: +@smallexample +typedef struct GTY(()) @{ + @dots{} + void ** GTY ((use_param, @dots{})) entries; + @dots{} +@} htab_t; +@end smallexample +and then declare variables like this: +@smallexample + static htab_t GTY ((param_is (union tree_node))) ict; +@end smallexample + +@findex param@var{n}_is +@findex use_param@var{n} +@item param@var{n}_is (@var{type}) +@itemx use_param@var{n} + +In more complicated cases, the data structure might need to work on +several different types, which might not necessarily all be pointers. +For this, @code{param1_is} through @code{param9_is} may be used to +specify the real type of a field identified by @code{use_param1} through +@code{use_param9}. + +@findex use_params +@item use_params + +When a structure contains another structure that is parameterized, +there's no need to do anything special, the inner structure inherits the +parameters of the outer one. When a structure contains a pointer to a +parameterized structure, the type machinery won't automatically detect +this (it could, it just doesn't yet), so it's necessary to tell it that +the pointed-to structure should use the same parameters as the outer +structure. This is done by marking the pointer with the +@code{use_params} option. + +@findex deletable +@item deletable + +@code{deletable}, when applied to a global variable, indicates that when +garbage collection runs, there's no need to mark anything pointed to +by this variable, it can just be set to @code{NULL} instead. This is used +to keep a list of free structures around for re-use. + +@findex if_marked +@item if_marked ("@var{expression}") + +Suppose you want some kinds of object to be unique, and so you put them +in a hash table. If garbage collection marks the hash table, these +objects will never be freed, even if the last other reference to them +goes away. GGC has special handling to deal with this: if you use the +@code{if_marked} option on a global hash table, GGC will call the +routine whose name is the parameter to the option on each hash table +entry. If the routine returns nonzero, the hash table entry will +be marked as usual. If the routine returns zero, the hash table entry +will be deleted. + +The routine @code{ggc_marked_p} can be used to determine if an element +has been marked already; in fact, the usual case is to use +@code{if_marked ("ggc_marked_p")}. + +@findex maybe_undef +@item maybe_undef + +When applied to a field, @code{maybe_undef} indicates that it's OK if +the structure that this fields points to is never defined, so long as +this field is always @code{NULL}. This is used to avoid requiring +backends to define certain optional structures. It doesn't work with +language frontends. + +@findex nested_ptr +@item nested_ptr (@var{type}, "@var{to expression}", "@var{from expression}") + +The type machinery expects all pointers to point to the start of an +object. Sometimes for abstraction purposes it's convenient to have +a pointer which points inside an object. So long as it's possible to +convert the original object to and from the pointer, such pointers +can still be used. @var{type} is the type of the original object, +the @var{to expression} returns the pointer given the original object, +and the @var{from expression} returns the original object given +the pointer. The pointer will be available using the @code{%h} +escape. + +@findex chain_next +@findex chain_prev +@item chain_next ("@var{expression}") +@itemx chain_prev ("@var{expression}") + +It's helpful for the type machinery to know if objects are often +chained together in long lists; this lets it generate code that uses +less stack space by iterating along the list instead of recursing down +it. @code{chain_next} is an expression for the next item in the list, +@code{chain_prev} is an expression for the previous item. For singly +linked lists, use only @code{chain_next}; for doubly linked lists, use +both. The machinery requires that taking the next item of the +previous item gives the original item. + +@findex reorder +@item reorder ("@var{function name}") + +Some data structures depend on the relative ordering of pointers. If +the precompiled header machinery needs to change that ordering, it +will call the function referenced by the @code{reorder} option, before +changing the pointers in the object that's pointed to by the field the +option applies to. The function must take four arguments, with the +signature @samp{@w{void *, void *, gt_pointer_operator, void *}}. +The first parameter is a pointer to the structure that contains the +object being updated, or the object itself if there is no containing +structure. The second parameter is a cookie that should be ignored. +The third parameter is a routine that, given a pointer, will update it +to its correct new value. The fourth parameter is a cookie that must +be passed to the second parameter. + +PCH cannot handle data structures that depend on the absolute values +of pointers. @code{reorder} functions can be expensive. When +possible, it is better to depend on properties of the data, like an ID +number or the hash of a string instead. + +@findex special +@item special ("@var{name}") + +The @code{special} option is used to mark types that have to be dealt +with by special case machinery. The parameter is the name of the +special case. See @file{gengtype.c} for further details. Avoid +adding new special cases unless there is no other alternative. +@end table + +@node GGC Roots +@section Marking Roots for the Garbage Collector +@cindex roots, marking +@cindex marking roots + +In addition to keeping track of types, the type machinery also locates +the global variables (@dfn{roots}) that the garbage collector starts +at. Roots must be declared using one of the following syntaxes: + +@itemize @bullet +@item +@code{extern GTY(([@var{options}])) @var{type} @var{name};} +@item +@code{static GTY(([@var{options}])) @var{type} @var{name};} +@end itemize +@noindent +The syntax +@itemize @bullet +@item +@code{GTY(([@var{options}])) @var{type} @var{name};} +@end itemize +@noindent +is @emph{not} accepted. There should be an @code{extern} declaration +of such a variable in a header somewhere---mark that, not the +definition. Or, if the variable is only used in one file, make it +@code{static}. + +@node Files +@section Source Files Containing Type Information +@cindex generated files +@cindex files, generated + +Whenever you add @code{GTY} markers to a source file that previously +had none, or create a new source file containing @code{GTY} markers, +there are three things you need to do: + +@enumerate +@item +You need to add the file to the list of source files the type +machinery scans. There are four cases: + +@enumerate a +@item +For a back-end file, this is usually done +automatically; if not, you should add it to @code{target_gtfiles} in +the appropriate port's entries in @file{config.gcc}. + +@item +For files shared by all front ends, add the filename to the +@code{GTFILES} variable in @file{Makefile.in}. + +@item +For files that are part of one front end, add the filename to the +@code{gtfiles} variable defined in the appropriate +@file{config-lang.in}. For C, the file is @file{c-config-lang.in}. + +@item +For files that are part of some but not all front ends, add the +filename to the @code{gtfiles} variable of @emph{all} the front ends +that use it. +@end enumerate + +@item +If the file was a header file, you'll need to check that it's included +in the right place to be visible to the generated files. For a back-end +header file, this should be done automatically. For a front-end header +file, it needs to be included by the same file that includes +@file{gtype-@var{lang}.h}. For other header files, it needs to be +included in @file{gtype-desc.c}, which is a generated file, so add it to +@code{ifiles} in @code{open_base_file} in @file{gengtype.c}. + +For source files that aren't header files, the machinery will generate a +header file that should be included in the source file you just changed. +The file will be called @file{gt-@var{path}.h} where @var{path} is the +pathname relative to the @file{gcc} directory with slashes replaced by +@verb{|-|}, so for example the header file to be included in +@file{cp/parser.c} is called @file{gt-cp-parser.c}. The +generated header file should be included after everything else in the +source file. Don't forget to mention this file as a dependency in the +@file{Makefile}! + +@end enumerate + +For language frontends, there is another file that needs to be included +somewhere. It will be called @file{gtype-@var{lang}.h}, where +@var{lang} is the name of the subdirectory the language is contained in. diff --git a/gcc-4.2.1-5666.3/gcc/doc/headerdirs.texi b/gcc-4.2.1-5666.3/gcc/doc/headerdirs.texi new file mode 100644 index 000000000..bc7f07f36 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/headerdirs.texi @@ -0,0 +1,32 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Header Dirs +@chapter Standard Header File Directories + +@code{GCC_INCLUDE_DIR} means the same thing for native and cross. It is +where GCC stores its private include files, and also where GCC +stores the fixed include files. A cross compiled GCC runs +@code{fixincludes} on the header files in @file{$(tooldir)/include}. +(If the cross compilation header files need to be fixed, they must be +installed before GCC is built. If the cross compilation header files +are already suitable for GCC, nothing special need be done). + +@code{GPLUSPLUS_INCLUDE_DIR} means the same thing for native and cross. It +is where @command{g++} looks first for header files. The C++ library +installs only target independent header files in that directory. + +@code{LOCAL_INCLUDE_DIR} is used only by native compilers. GCC +doesn't install anything there. It is normally +@file{/usr/local/include}. This is where local additions to a packaged +system should place header files. + +@code{CROSS_INCLUDE_DIR} is used only by cross compilers. GCC +doesn't install anything there. + +@code{TOOL_INCLUDE_DIR} is used for both native and cross compilers. It +is the place for other packages to install header files that GCC will +use. For a cross-compiler, this is the equivalent of +@file{/usr/include}. When you build a cross-compiler, +@code{fixincludes} processes any header files in this directory. diff --git a/gcc-4.2.1-5666.3/gcc/doc/hostconfig.texi b/gcc-4.2.1-5666.3/gcc/doc/hostconfig.texi new file mode 100644 index 000000000..1c97ac278 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/hostconfig.texi @@ -0,0 +1,220 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, +@c 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gccint.texi. + +@node Host Config +@chapter Host Configuration +@cindex host configuration + +Most details about the machine and system on which the compiler is +actually running are detected by the @command{configure} script. Some +things are impossible for @command{configure} to detect; these are +described in two ways, either by macros defined in a file named +@file{xm-@var{machine}.h} or by hook functions in the file specified +by the @var{out_host_hook_obj} variable in @file{config.gcc}. (The +intention is that very few hosts will need a header file but nearly +every fully supported host will need to override some hooks.) + +If you need to define only a few macros, and they have simple +definitions, consider using the @code{xm_defines} variable in your +@file{config.gcc} entry instead of creating a host configuration +header. @xref{System Config}. + +@menu +* Host Common:: Things every host probably needs implemented. +* Filesystem:: Your host can't have the letter `a' in filenames? +* Host Misc:: Rare configuration options for hosts. +@end menu + +@node Host Common +@section Host Common +@cindex host hooks +@cindex host functions + +Some things are just not portable, even between similar operating systems, +and are too difficult for autoconf to detect. They get implemented using +hook functions in the file specified by the @var{host_hook_obj} +variable in @file{config.gcc}. + +@deftypefn {Host Hook} void HOST_HOOKS_EXTRA_SIGNALS (void) +This host hook is used to set up handling for extra signals. The most +common thing to do in this hook is to detect stack overflow. +@end deftypefn + +@deftypefn {Host Hook} void * HOST_HOOKS_GT_PCH_GET_ADDRESS (size_t @var{size}, int @var{fd}) +This host hook returns the address of some space that is likely to be +free in some subsequent invocation of the compiler. We intend to load +the PCH data at this address such that the data need not be relocated. +The area should be able to hold @var{size} bytes. If the host uses +@code{mmap}, @var{fd} is an open file descriptor that can be used for +probing. +@end deftypefn + +@deftypefn {Host Hook} int HOST_HOOKS_GT_PCH_USE_ADDRESS (void * @var{address}, size_t @var{size}, int @var{fd}, size_t @var{offset}) +This host hook is called when a PCH file is about to be loaded. +We want to load @var{size} bytes from @var{fd} at @var{offset} +into memory at @var{address}. The given address will be the result of +a previous invocation of @code{HOST_HOOKS_GT_PCH_GET_ADDRESS}. +Return @minus{}1 if we couldn't allocate @var{size} bytes at @var{address}. +Return 0 if the memory is allocated but the data is not loaded. Return 1 +if the hook has performed everything. + +If the implementation uses reserved address space, free any reserved +space beyond @var{size}, regardless of the return value. If no PCH will +be loaded, this hook may be called with @var{size} zero, in which case +all reserved address space should be freed. + +Do not try to handle values of @var{address} that could not have been +returned by this executable; just return @minus{}1. Such values usually +indicate an out-of-date PCH file (built by some other GCC executable), +and such a PCH file won't work. +@end deftypefn + +@deftypefn {Host Hook} size_t HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY (void); +This host hook returns the alignment required for allocating virtual +memory. Usually this is the same as getpagesize, but on some hosts the +alignment for reserving memory differs from the pagesize for committing +memory. +@end deftypefn + +@node Filesystem +@section Host Filesystem +@cindex configuration file +@cindex @file{xm-@var{machine}.h} + +GCC needs to know a number of things about the semantics of the host +machine's filesystem. Filesystems with Unix and MS-DOS semantics are +automatically detected. For other systems, you can define the +following macros in @file{xm-@var{machine}.h}. + +@ftable @code +@item HAVE_DOS_BASED_FILE_SYSTEM +This macro is automatically defined by @file{system.h} if the host +file system obeys the semantics defined by MS-DOS instead of Unix. +DOS file systems are case insensitive, file specifications may begin +with a drive letter, and both forward slash and backslash (@samp{/} +and @samp{\}) are directory separators. + +@item DIR_SEPARATOR +@itemx DIR_SEPARATOR_2 +If defined, these macros expand to character constants specifying +separators for directory names within a file specification. +@file{system.h} will automatically give them appropriate values on +Unix and MS-DOS file systems. If your file system is neither of +these, define one or both appropriately in @file{xm-@var{machine}.h}. + +However, operating systems like VMS, where constructing a pathname is +more complicated than just stringing together directory names +separated by a special character, should not define either of these +macros. + +@item PATH_SEPARATOR +If defined, this macro should expand to a character constant +specifying the separator for elements of search paths. The default +value is a colon (@samp{:}). DOS-based systems usually, but not +always, use semicolon (@samp{;}). + +@item VMS +Define this macro if the host system is VMS@. + +@item HOST_OBJECT_SUFFIX +Define this macro to be a C string representing the suffix for object +files on your host machine. If you do not define this macro, GCC will +use @samp{.o} as the suffix for object files. + +@item HOST_EXECUTABLE_SUFFIX +Define this macro to be a C string representing the suffix for +executable files on your host machine. If you do not define this macro, +GCC will use the null string as the suffix for executable files. + +@item HOST_BIT_BUCKET +A pathname defined by the host operating system, which can be opened as +a file and written to, but all the information written is discarded. +This is commonly known as a @dfn{bit bucket} or @dfn{null device}. If +you do not define this macro, GCC will use @samp{/dev/null} as the bit +bucket. If the host does not support a bit bucket, define this macro to +an invalid filename. + +@item UPDATE_PATH_HOST_CANONICALIZE (@var{path}) +If defined, a C statement (sans semicolon) that performs host-dependent +canonicalization when a path used in a compilation driver or +preprocessor is canonicalized. @var{path} is a malloc-ed path to be +canonicalized. If the C statement does canonicalize @var{path} into a +different buffer, the old path should be freed and the new buffer should +have been allocated with malloc. + +@item DUMPFILE_FORMAT +Define this macro to be a C string representing the format to use for +constructing the index part of debugging dump file names. The resultant +string must fit in fifteen bytes. The full filename will be the +concatenation of: the prefix of the assembler file name, the string +resulting from applying this format to an index number, and a string +unique to each dump file kind, e.g.@: @samp{rtl}. + +If you do not define this macro, GCC will use @samp{.%02d.}. You should +define this macro if using the default will create an invalid file name. + +@item DELETE_IF_ORDINARY +Define this macro to be a C statement (sans semicolon) that performs +host-dependent removal of ordinary temp files in the compilation driver. + +If you do not define this macro, GCC will use the default version. You +should define this macro if the default version does not reliably remove +the temp file as, for example, on VMS which allows multiple versions +of a file. + +@item HOST_LACKS_INODE_NUMBERS +Define this macro if the host filesystem does not report meaningful inode +numbers in struct stat. +@end ftable + +@node Host Misc +@section Host Misc +@cindex configuration file +@cindex @file{xm-@var{machine}.h} + +@ftable @code +@item FATAL_EXIT_CODE +A C expression for the status code to be returned when the compiler +exits after serious errors. The default is the system-provided macro +@samp{EXIT_FAILURE}, or @samp{1} if the system doesn't define that +macro. Define this macro only if these defaults are incorrect. + +@item SUCCESS_EXIT_CODE +A C expression for the status code to be returned when the compiler +exits without serious errors. (Warnings are not serious errors.) The +default is the system-provided macro @samp{EXIT_SUCCESS}, or @samp{0} if +the system doesn't define that macro. Define this macro only if these +defaults are incorrect. + +@item USE_C_ALLOCA +Define this macro if GCC should use the C implementation of @code{alloca} +provided by @file{libiberty.a}. This only affects how some parts of the +compiler itself allocate memory. It does not change code generation. + +When GCC is built with a compiler other than itself, the C @code{alloca} +is always used. This is because most other implementations have serious +bugs. You should define this macro only on a system where no +stack-based @code{alloca} can possibly work. For instance, if a system +has a small limit on the size of the stack, GCC's builtin @code{alloca} +will not work reliably. + +@item COLLECT2_HOST_INITIALIZATION +If defined, a C statement (sans semicolon) that performs host-dependent +initialization when @code{collect2} is being initialized. + +@item GCC_DRIVER_HOST_INITIALIZATION +If defined, a C statement (sans semicolon) that performs host-dependent +initialization when a compilation driver is being initialized. + +@item HOST_LONG_LONG_FORMAT +If defined, the string used to indicate an argument of type @code{long +long} to functions like @code{printf}. The default value is +@code{"ll"}. +@end ftable + +In addition, if @command{configure} generates an incorrect definition of +any of the macros in @file{auto-host.h}, you can override that +definition in a host configuration header. If you need to do this, +first see if it is possible to fix @command{configure}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/implement-c.texi b/gcc-4.2.1-5666.3/gcc/doc/implement-c.texi new file mode 100644 index 000000000..dc996104a --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/implement-c.texi @@ -0,0 +1,675 @@ +@c Copyright (C) 2001,2002,2003,2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node C Implementation +@chapter C Implementation-defined behavior +@cindex implementation-defined behavior, C language + +A conforming implementation of ISO C is required to document its +choice of behavior in each of the areas that are designated +``implementation defined''. The following lists all such areas, +along with the section numbers from the ISO/IEC 9899:1990 and ISO/IEC +9899:1999 standards. Some areas are only implementation-defined in +one version of the standard. + +Some choices depend on the externally determined ABI for the platform +(including standard character encodings) which GCC follows; these are +listed as ``determined by ABI'' below. @xref{Compatibility, , Binary +Compatibility}, and @uref{http://gcc.gnu.org/readings.html}. Some +choices are documented in the preprocessor manual. +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. Some choices are made by the +library and operating system (or other environment when compiling for +a freestanding environment); refer to their documentation for details. + +@menu +* Translation implementation:: +* Environment implementation:: +* Identifiers implementation:: +* Characters implementation:: +* Integers implementation:: +* Floating point implementation:: +* Arrays and pointers implementation:: +* Hints implementation:: +* Structures unions enumerations and bit-fields implementation:: +* Qualifiers implementation:: +* Declarators implementation:: +* Statements implementation:: +* Preprocessing directives implementation:: +* Library functions implementation:: +* Architecture implementation:: +* Locale-specific behavior implementation:: +@end menu + +@node Translation implementation +@section Translation + +@itemize @bullet +@item +@cite{How a diagnostic is identified (C90 3.7, C99 3.10, C90 and C99 5.1.1.3).} + +Diagnostics consist of all the output sent to stderr by GCC@. + +@item +@cite{Whether each nonempty sequence of white-space characters other than +new-line is retained or replaced by one space character in translation +phase 3 (C90 and C99 5.1.1.2).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@end itemize + +@node Environment implementation +@section Environment + +The behavior of most of these points are dependent on the implementation +of the C library, and are not defined by GCC itself. + +@itemize @bullet +@item +@cite{The mapping between physical source file multibyte characters +and the source character set in translation phase 1 (C90 and C99 5.1.1.2).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@end itemize + +@node Identifiers implementation +@section Identifiers + +@itemize @bullet +@item +@cite{Which additional multibyte characters may appear in identifiers +and their correspondence to universal character names (C99 6.4.2).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@item +@cite{The number of significant initial characters in an identifier +(C90 6.1.2, C90 and C99 5.2.4.1, C99 6.4.2).} + +For internal names, all characters are significant. For external names, +the number of significant characters are defined by the linker; for +almost all targets, all characters are significant. + +@item +@cite{Whether case distinctions are significant in an identifier with +external linkage (C90 6.1.2).} + +This is a property of the linker. C99 requires that case distinctions +are always significant in identifiers with external linkage and +systems without this property are not supported by GCC@. + +@end itemize + +@node Characters implementation +@section Characters + +@itemize @bullet +@item +@cite{The number of bits in a byte (C90 3.4, C99 3.6).} + +Determined by ABI@. + +@item +@cite{The values of the members of the execution character set (C90 +and C99 5.2.1).} + +Determined by ABI@. + +@item +@cite{The unique value of the member of the execution character set produced +for each of the standard alphabetic escape sequences (C90 and C99 5.2.2).} + +Determined by ABI@. + +@item +@cite{The value of a @code{char} object into which has been stored any +character other than a member of the basic execution character set +(C90 6.1.2.5, C99 6.2.5).} + +Determined by ABI@. + +@item +@cite{Which of @code{signed char} or @code{unsigned char} has the same +range, representation, and behavior as ``plain'' @code{char} (C90 +6.1.2.5, C90 6.2.1.1, C99 6.2.5, C99 6.3.1.1).} + +@opindex fsigned-char +@opindex funsigned-char +Determined by ABI@. The options @option{-funsigned-char} and +@option{-fsigned-char} change the default. @xref{C Dialect Options, , +Options Controlling C Dialect}. + +@item +@cite{The mapping of members of the source character set (in character +constants and string literals) to members of the execution character +set (C90 6.1.3.4, C99 6.4.4.4, C90 and C99 5.1.1.2).} + +Determined by ABI@. + +@item +@cite{The value of an integer character constant containing more than one +character or containing a character or escape sequence that does not map +to a single-byte execution character (C90 6.1.3.4, C99 6.4.4.4).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@item +@cite{The value of a wide character constant containing more than one +multibyte character, or containing a multibyte character or escape +sequence not represented in the extended execution character set (C90 +6.1.3.4, C99 6.4.4.4).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@item +@cite{The current locale used to convert a wide character constant consisting +of a single multibyte character that maps to a member of the extended +execution character set into a corresponding wide character code (C90 +6.1.3.4, C99 6.4.4.4).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@item +@cite{The current locale used to convert a wide string literal into +corresponding wide character codes (C90 6.1.4, C99 6.4.5).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. + +@item +@cite{The value of a string literal containing a multibyte character or escape +sequence not represented in the execution character set (C90 6.1.4, C99 6.4.5).} + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}. +@end itemize + +@node Integers implementation +@section Integers + +@itemize @bullet +@item +@cite{Any extended integer types that exist in the implementation (C99 6.2.5).} + +GCC does not support any extended integer types. +@c The __mode__ attribute might create types of precisions not +@c otherwise supported, but the syntax isn't right for use everywhere +@c the standard type names might be used. Predefined typedefs should +@c be used if any extended integer types are to be defined. The +@c __int128_t and __uint128_t typedefs are not extended integer types +@c as they are generally longer than the ABI-specified intmax_t. + +@item +@cite{Whether signed integer types are represented using sign and magnitude, +two's complement, or one's complement, and whether the extraordinary value +is a trap representation or an ordinary value (C99 6.2.6.2).} + +GCC supports only two's complement integer types, and all bit patterns +are ordinary values. + +@item +@cite{The rank of any extended integer type relative to another extended +integer type with the same precision (C99 6.3.1.1).} + +GCC does not support any extended integer types. +@c If it did, there would only be one of each precision and signedness. + +@item +@cite{The result of, or the signal raised by, converting an integer to a +signed integer type when the value cannot be represented in an object of +that type (C90 6.2.1.2, C99 6.3.1.3).} + +For conversion to a type of width @math{N}, the value is reduced +modulo @math{2^N} to be within range of the type; no signal is raised. + +@item +@cite{The results of some bitwise operations on signed integers (C90 +6.3, C99 6.5).} + +Bitwise operators act on the representation of the value including +both the sign and value bits, where the sign bit is considered +immediately above the highest-value value bit. Signed @samp{>>} acts +on negative numbers by sign extension. + +GCC does not use the latitude given in C99 only to treat certain +aspects of signed @samp{<<} as undefined, but this is subject to +change. + +@item +@cite{The sign of the remainder on integer division (C90 6.3.5).} + +GCC always follows the C99 requirement that the result of division is +truncated towards zero. + +@end itemize + +@node Floating point implementation +@section Floating point + +@itemize @bullet +@item +@cite{The accuracy of the floating-point operations and of the library +functions in @code{<math.h>} and @code{<complex.h>} that return floating-point +results (C90 and C99 5.2.4.2.2).} + +The accuracy is unknown. + +@item +@cite{The rounding behaviors characterized by non-standard values +of @code{FLT_ROUNDS} @gol +(C90 and C99 5.2.4.2.2).} + +GCC does not use such values. + +@item +@cite{The evaluation methods characterized by non-standard negative +values of @code{FLT_EVAL_METHOD} (C99 5.2.4.2.2).} + +GCC does not use such values. + +@item +@cite{The direction of rounding when an integer is converted to a +floating-point number that cannot exactly represent the original +value (C90 6.2.1.3, C99 6.3.1.4).} + +C99 Annex F is followed. + +@item +@cite{The direction of rounding when a floating-point number is +converted to a narrower floating-point number (C90 6.2.1.4, C99 +6.3.1.5).} + +C99 Annex F is followed. + +@item +@cite{How the nearest representable value or the larger or smaller +representable value immediately adjacent to the nearest representable +value is chosen for certain floating constants (C90 6.1.3.1, C99 +6.4.4.2).} + +C99 Annex F is followed. + +@item +@cite{Whether and how floating expressions are contracted when not +disallowed by the @code{FP_CONTRACT} pragma (C99 6.5).} + +Expressions are currently only contracted if +@option{-funsafe-math-optimizations} or @option{-ffast-math} are used. +This is subject to change. + +@item +@cite{The default state for the @code{FENV_ACCESS} pragma (C99 7.6.1).} + +This pragma is not implemented, but the default is to ``off'' unless +@option{-frounding-math} is used in which case it is ``on''. + +@item +@cite{Additional floating-point exceptions, rounding modes, environments, +and classifications, and their macro names (C99 7.6, C99 7.12).} + +This is dependent on the implementation of the C library, and is not +defined by GCC itself. + +@item +@cite{The default state for the @code{FP_CONTRACT} pragma (C99 7.12.2).} + +This pragma is not implemented. Expressions are currently only +contracted if @option{-funsafe-math-optimizations} or +@option{-ffast-math} are used. This is subject to change. + +@item +@cite{Whether the ``inexact'' floating-point exception can be raised +when the rounded result actually does equal the mathematical result +in an IEC 60559 conformant implementation (C99 F.9).} + +This is dependent on the implementation of the C library, and is not +defined by GCC itself. + +@item +@cite{Whether the ``underflow'' (and ``inexact'') floating-point +exception can be raised when a result is tiny but not inexact in an +IEC 60559 conformant implementation (C99 F.9).} + +This is dependent on the implementation of the C library, and is not +defined by GCC itself. + +@end itemize + +@node Arrays and pointers implementation +@section Arrays and pointers + +@itemize @bullet +@item +@cite{The result of converting a pointer to an integer or +vice versa (C90 6.3.4, C99 6.3.2.3).} + +A cast from pointer to integer discards most-significant bits if the +pointer representation is larger than the integer type, +sign-extends@footnote{Future versions of GCC may zero-extend, or use +a target-defined @code{ptr_extend} pattern. Do not rely on sign extension.} +if the pointer representation is smaller than the integer type, otherwise +the bits are unchanged. +@c ??? We've always claimed that pointers were unsigned entities. +@c Shouldn't we therefore be doing zero-extension? If so, the bug +@c is in convert_to_integer, where we call type_for_size and request +@c a signed integral type. On the other hand, it might be most useful +@c for the target if we extend according to POINTERS_EXTEND_UNSIGNED. + +A cast from integer to pointer discards most-significant bits if the +pointer representation is smaller than the integer type, extends according +to the signedness of the integer type if the pointer representation +is larger than the integer type, otherwise the bits are unchanged. + +When casting from pointer to integer and back again, the resulting +pointer must reference the same object as the original pointer, otherwise +the behavior is undefined. That is, one may not use integer arithmetic to +avoid the undefined behavior of pointer arithmetic as proscribed in +C99 6.5.6/8. + +@item +@cite{The size of the result of subtracting two pointers to elements +of the same array (C90 6.3.6, C99 6.5.6).} + +The value is as specified in the standard and the type is determined +by the ABI@. + +@end itemize + +@node Hints implementation +@section Hints + +@itemize @bullet +@item +@cite{The extent to which suggestions made by using the @code{register} +storage-class specifier are effective (C90 6.5.1, C99 6.7.1).} + +The @code{register} specifier affects code generation only in these ways: + +@itemize @bullet +@item +When used as part of the register variable extension, see +@ref{Explicit Reg Vars}. + +@item +When @option{-O0} is in use, the compiler allocates distinct stack +memory for all variables that do not have the @code{register} +storage-class specifier; if @code{register} is specified, the variable +may have a shorter lifespan than the code would indicate and may never +be placed in memory. + +@item +On some rare x86 targets, @code{setjmp} doesn't save the registers in +all circumstances. In those cases, GCC doesn't allocate any variables +in registers unless they are marked @code{register}. + +@end itemize + +@item +@cite{The extent to which suggestions made by using the inline function +specifier are effective (C99 6.7.4).} + +GCC will not inline any functions if the @option{-fno-inline} option is +used or if @option{-O0} is used. Otherwise, GCC may still be unable to +inline a function for many reasons; the @option{-Winline} option may be +used to determine if a function has not been inlined and why not. + +@end itemize + +@node Structures unions enumerations and bit-fields implementation +@section Structures, unions, enumerations, and bit-fields + +@itemize @bullet +@item +@cite{A member of a union object is accessed using a member of a +different type (C90 6.3.2.3).} + +The relevant bytes of the representation of the object are treated as +an object of the type used for the access. This may be a trap +representation. + +@item +@cite{Whether a ``plain'' @code{int} bit-field is treated as a +@code{signed int} bit-field or as an @code{unsigned int} bit-field +(C90 6.5.2, C90 6.5.2.1, C99 6.7.2, C99 6.7.2.1).} + +@opindex funsigned-bitfields +By default it is treated as @code{signed int} but this may be changed +by the @option{-funsigned-bitfields} option. + +@item +@cite{Allowable bit-field types other than @code{_Bool}, @code{signed int}, +and @code{unsigned int} (C99 6.7.2.1).} + +No other types are permitted in strictly conforming mode. +@c Would it be better to restrict the pedwarn for other types to C90 +@c mode and document the other types for C99 mode? + +@item +@cite{Whether a bit-field can straddle a storage-unit boundary (C90 +6.5.2.1, C99 6.7.2.1).} + +Determined by ABI@. + +@item +@cite{The order of allocation of bit-fields within a unit (C90 +6.5.2.1, C99 6.7.2.1).} + +Determined by ABI@. + +@item +@cite{The alignment of non-bit-field members of structures (C90 +6.5.2.1, C99 6.7.2.1).} + +Determined by ABI@. + +@item +@cite{The integer type compatible with each enumerated type (C90 +6.5.2.2, C99 6.7.2.2).} + +@opindex fshort-enums +Normally, the type is @code{unsigned int} if there are no negative +values in the enumeration, otherwise @code{int}. If +@option{-fshort-enums} is specified, then if there are negative values +it is the first of @code{signed char}, @code{short} and @code{int} +that can represent all the values, otherwise it is the first of +@code{unsigned char}, @code{unsigned short} and @code{unsigned int} +that can represent all the values. +@c On a few unusual targets with 64-bit int, this doesn't agree with +@c the code and one of the types accessed via mode attributes (which +@c are not currently considered extended integer types) may be used. +@c If these types are made extended integer types, it would still be +@c the case that -fshort-enums stops the implementation from +@c conforming to C90 on those targets. + +On some targets, @option{-fshort-enums} is the default; this is +determined by the ABI@. + +@end itemize + +@node Qualifiers implementation +@section Qualifiers + +@itemize @bullet +@item +@cite{What constitutes an access to an object that has volatile-qualified +type (C90 6.5.3, C99 6.7.3).} + +Such an object is normally accessed by pointers and used for accessing +hardware. In most expressions, it is intuitively obvious what is a read +and what is a write. For example + +@smallexample +volatile int *dst = @var{somevalue}; +volatile int *src = @var{someothervalue}; +*dst = *src; +@end smallexample + +@noindent +will cause a read of the volatile object pointed to by @var{src} and store the +value into the volatile object pointed to by @var{dst}. There is no +guarantee that these reads and writes are atomic, especially for objects +larger than @code{int}. + +However, if the volatile storage is not being modified, and the value of +the volatile storage is not used, then the situation is less obvious. +For example + +@smallexample +volatile int *src = @var{somevalue}; +*src; +@end smallexample + +According to the C standard, such an expression is an rvalue whose type +is the unqualified version of its original type, i.e. @code{int}. Whether +GCC interprets this as a read of the volatile object being pointed to or +only as a request to evaluate the expression for its side-effects depends +on this type. + +If it is a scalar type, or on most targets an aggregate type whose only +member object is of a scalar type, or a union type whose member objects +are of scalar types, the expression is interpreted by GCC as a read of +the volatile object; in the other cases, the expression is only evaluated +for its side-effects. + +@end itemize + +@node Declarators implementation +@section Declarators + +@itemize @bullet +@item +@cite{The maximum number of declarators that may modify an arithmetic, +structure or union type (C90 6.5.4).} + +GCC is only limited by available memory. + +@end itemize + +@node Statements implementation +@section Statements + +@itemize @bullet +@item +@cite{The maximum number of @code{case} values in a @code{switch} +statement (C90 6.6.4.2).} + +GCC is only limited by available memory. + +@end itemize + +@node Preprocessing directives implementation +@section Preprocessing directives + +@xref{Implementation-defined behavior, , Implementation-defined +behavior, cpp, The C Preprocessor}, for details of these aspects of +implementation-defined behavior. + +@itemize @bullet +@item +@cite{How sequences in both forms of header names are mapped to headers +or external source file names (C90 6.1.7, C99 6.4.7).} + +@item +@cite{Whether the value of a character constant in a constant expression +that controls conditional inclusion matches the value of the same character +constant in the execution character set (C90 6.8.1, C99 6.10.1).} + +@item +@cite{Whether the value of a single-character character constant in a +constant expression that controls conditional inclusion may have a +negative value (C90 6.8.1, C99 6.10.1).} + +@item +@cite{The places that are searched for an included @samp{<>} delimited +header, and how the places are specified or the header is +identified (C90 6.8.2, C99 6.10.2).} + +@item +@cite{How the named source file is searched for in an included @samp{""} +delimited header (C90 6.8.2, C99 6.10.2).} + +@item +@cite{The method by which preprocessing tokens (possibly resulting from +macro expansion) in a @code{#include} directive are combined into a header +name (C90 6.8.2, C99 6.10.2).} + +@item +@cite{The nesting limit for @code{#include} processing (C90 6.8.2, C99 +6.10.2).} + +@item +@cite{Whether the @samp{#} operator inserts a @samp{\} character before +the @samp{\} character that begins a universal character name in a +character constant or string literal (C99 6.10.3.2).} + +@item +@cite{The behavior on each recognized non-@code{STDC #pragma} +directive (C90 6.8.6, C99 6.10.6).} + +@xref{Pragmas, , Pragmas, cpp, The C Preprocessor}, for details of +pragmas accepted by GCC on all targets. @xref{Pragmas, , Pragmas +Accepted by GCC}, for details of target-specific pragmas. + +@item +@cite{The definitions for @code{__DATE__} and @code{__TIME__} when +respectively, the date and time of translation are not available (C90 +6.8.8, C99 6.10.8).} + +@end itemize + +@node Library functions implementation +@section Library functions + +The behavior of most of these points are dependent on the implementation +of the C library, and are not defined by GCC itself. + +@itemize @bullet +@item +@cite{The null pointer constant to which the macro @code{NULL} expands +(C90 7.1.6, C99 7.17).} + +In @code{<stddef.h>}, @code{NULL} expands to @code{((void *)0)}. GCC +does not provide the other headers which define @code{NULL} and some +library implementations may use other definitions in those headers. + +@end itemize + +@node Architecture implementation +@section Architecture + +@itemize @bullet +@item +@cite{The values or expressions assigned to the macros specified in the +headers @code{<float.h>}, @code{<limits.h>}, and @code{<stdint.h>} +(C90 and C99 5.2.4.2, C99 7.18.2, C99 7.18.3).} + +Determined by ABI@. + +@item +@cite{The number, order, and encoding of bytes in any object +(when not explicitly specified in this International Standard) (C99 6.2.6.1).} + +Determined by ABI@. + +@item +@cite{The value of the result of the @code{sizeof} operator (C90 +6.3.3.4, C99 6.5.3.4).} + +Determined by ABI@. + +@end itemize + +@node Locale-specific behavior implementation +@section Locale-specific behavior + +The behavior of these points are dependent on the implementation +of the C library, and are not defined by GCC itself. diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/fdl.texi b/gcc-4.2.1-5666.3/gcc/doc/include/fdl.texi new file mode 100644 index 000000000..74651448e --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/fdl.texi @@ -0,0 +1,483 @@ +@ignore +@c Set file name and title for man page. +@setfilename gfdl +@settitle GNU Free Documentation License +@c man begin SEEALSO +gpl(7), fsf-funding(7). +@c man end +@c man begin COPYRIGHT +Copyright @copyright{} 2000,2001,2002 Free Software Foundation, Inc. +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +@c man end +@end ignore +@c Special handling for inclusion in the install manual. +@ifset gfdlhtml +@ifnothtml +@comment node-name, next, previous, up +@node GNU Free Documentation License, Concept Index, Old, Top +@end ifnothtml +@html +<h1 align="center">Installing GCC: GNU Free Documentation License</h1> +@end html +@ifnothtml +@unnumbered GNU Free Documentation License +@end ifnothtml +@end ifset +@c man begin DESCRIPTION +@ifclear gfdlhtml +@node GNU Free Documentation License +@unnumbered GNU Free Documentation License +@end ifclear + +@cindex FDL, GNU Free Documentation License +@center Version 1.2, November 2002 + +@display +Copyright @copyright{} 2000,2001,2002 Free Software Foundation, Inc. +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +@end display + +@enumerate 0 +@item +PREAMBLE + +The purpose of this License is to make a manual, textbook, or other +functional and useful document @dfn{free} in the sense of freedom: to +assure everyone the effective freedom to copy and redistribute it, +with or without modifying it, either commercially or noncommercially. +Secondarily, this License preserves for the author and publisher a way +to get credit for their work, while not being considered responsible +for modifications made by others. + +This License is a kind of ``copyleft'', which means that derivative +works of the document must themselves be free in the same sense. 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You may use the same title as a previous version +if the original publisher of that version gives permission. + +@item +List on the Title Page, as authors, one or more persons or entities +responsible for authorship of the modifications in the Modified +Version, together with at least five of the principal authors of the +Document (all of its principal authors, if it has fewer than five), +unless they release you from this requirement. + +@item +State on the Title page the name of the publisher of the +Modified Version, as the publisher. + +@item +Preserve all the copyright notices of the Document. + +@item +Add an appropriate copyright notice for your modifications +adjacent to the other copyright notices. + +@item +Include, immediately after the copyright notices, a license notice +giving the public permission to use the Modified Version under the +terms of this License, in the form shown in the Addendum below. + +@item +Preserve in that license notice the full lists of Invariant Sections +and required Cover Texts given in the Document's license notice. + +@item +Include an unaltered copy of this License. + +@item +Preserve the section Entitled ``History'', Preserve its Title, and add +to it an item stating at least the title, year, new authors, and +publisher of the Modified Version as given on the Title Page. If +there is no section Entitled ``History'' in the Document, create one +stating the title, year, authors, and publisher of the Document as +given on its Title Page, then add an item describing the Modified +Version as stated in the previous sentence. + +@item +Preserve the network location, if any, given in the Document for +public access to a Transparent copy of the Document, and likewise +the network locations given in the Document for previous versions +it was based on. These may be placed in the ``History'' section. +You may omit a network location for a work that was published at +least four years before the Document itself, or if the original +publisher of the version it refers to gives permission. + +@item +For any section Entitled ``Acknowledgements'' or ``Dedications'', Preserve +the Title of the section, and preserve in the section all the +substance and tone of each of the contributor acknowledgements and/or +dedications given therein. + +@item +Preserve all the Invariant Sections of the Document, +unaltered in their text and in their titles. Section numbers +or the equivalent are not considered part of the section titles. + +@item +Delete any section Entitled ``Endorsements''. Such a section +may not be included in the Modified Version. + +@item +Do not retitle any existing section to be Entitled ``Endorsements'' or +to conflict in title with any Invariant Section. + +@item +Preserve any Warranty Disclaimers. +@end enumerate + +If the Modified Version includes new front-matter sections or +appendices that qualify as Secondary Sections and contain no material +copied from the Document, you may at your option designate some or all +of these sections as invariant. To do this, add their titles to the +list of Invariant Sections in the Modified Version's license notice. +These titles must be distinct from any other section titles. + +You may add a section Entitled ``Endorsements'', provided it contains +nothing but endorsements of your Modified Version by various +parties---for example, statements of peer review or that the text has +been approved by an organization as the authoritative definition of a +standard. + +You may add a passage of up to five words as a Front-Cover Text, and a +passage of up to 25 words as a Back-Cover Text, to the end of the list +of Cover Texts in the Modified Version. Only one passage of +Front-Cover Text and one of Back-Cover Text may be added by (or +through arrangements made by) any one entity. If the Document already +includes a cover text for the same cover, previously added by you or +by arrangement made by the same entity you are acting on behalf of, +you may not add another; but you may replace the old one, on explicit +permission from the previous publisher that added the old one. + +The author(s) and publisher(s) of the Document do not by this License +give permission to use their names for publicity for or to assert or +imply endorsement of any Modified Version. + +@item +COMBINING DOCUMENTS + +You may combine the Document with other documents released under this +License, under the terms defined in section 4 above for modified +versions, provided that you include in the combination all of the +Invariant Sections of all of the original documents, unmodified, and +list them all as Invariant Sections of your combined work in its +license notice, and that you preserve all their Warranty Disclaimers. + +The combined work need only contain one copy of this License, and +multiple identical Invariant Sections may be replaced with a single +copy. If there are multiple Invariant Sections with the same name but +different contents, make the title of each such section unique by +adding at the end of it, in parentheses, the name of the original +author or publisher of that section if known, or else a unique number. +Make the same adjustment to the section titles in the list of +Invariant Sections in the license notice of the combined work. + +In the combination, you must combine any sections Entitled ``History'' +in the various original documents, forming one section Entitled +``History''; likewise combine any sections Entitled ``Acknowledgements'', +and any sections Entitled ``Dedications''. You must delete all +sections Entitled ``Endorsements.'' + +@item +COLLECTIONS OF DOCUMENTS + +You may make a collection consisting of the Document and other documents +released under this License, and replace the individual copies of this +License in the various documents with a single copy that is included in +the collection, provided that you follow the rules of this License for +verbatim copying of each of the documents in all other respects. + +You may extract a single document from such a collection, and distribute +it individually under this License, provided you insert a copy of this +License into the extracted document, and follow this License in all +other respects regarding verbatim copying of that document. + +@item +AGGREGATION WITH INDEPENDENT WORKS + +A compilation of the Document or its derivatives with other separate +and independent documents or works, in or on a volume of a storage or +distribution medium, is called an ``aggregate'' if the copyright +resulting from the compilation is not used to limit the legal rights +of the compilation's users beyond what the individual works permit. +When the Document is included in an aggregate, this License does not +apply to the other works in the aggregate which are not themselves +derivative works of the Document. + +If the Cover Text requirement of section 3 is applicable to these +copies of the Document, then if the Document is less than one half of +the entire aggregate, the Document's Cover Texts may be placed on +covers that bracket the Document within the aggregate, or the +electronic equivalent of covers if the Document is in electronic form. +Otherwise they must appear on printed covers that bracket the whole +aggregate. + +@item +TRANSLATION + +Translation is considered a kind of modification, so you may +distribute translations of the Document under the terms of section 4. +Replacing Invariant Sections with translations requires special +permission from their copyright holders, but you may include +translations of some or all Invariant Sections in addition to the +original versions of these Invariant Sections. You may include a +translation of this License, and all the license notices in the +Document, and any Warranty Disclaimers, provided that you also include +the original English version of this License and the original versions +of those notices and disclaimers. In case of a disagreement between +the translation and the original version of this License or a notice +or disclaimer, the original version will prevail. + +If a section in the Document is Entitled ``Acknowledgements'', +``Dedications'', or ``History'', the requirement (section 4) to Preserve +its Title (section 1) will typically require changing the actual +title. + +@item +TERMINATION + +You may not copy, modify, sublicense, or distribute the Document except +as expressly provided for under this License. Any other attempt to +copy, modify, sublicense or distribute the Document is void, and will +automatically terminate your rights under this License. However, +parties who have received copies, or rights, from you under this +License will not have their licenses terminated so long as such +parties remain in full compliance. + +@item +FUTURE REVISIONS OF THIS LICENSE + +The Free Software Foundation may publish new, revised versions +of the GNU Free Documentation License from time to time. Such new +versions will be similar in spirit to the present version, but may +differ in detail to address new problems or concerns. See +@uref{http://www.gnu.org/copyleft/}. + +Each version of the License is given a distinguishing version number. +If the Document specifies that a particular numbered version of this +License ``or any later version'' applies to it, you have the option of +following the terms and conditions either of that specified version or +of any later version that has been published (not as a draft) by the +Free Software Foundation. If the Document does not specify a version +number of this License, you may choose any version ever published (not +as a draft) by the Free Software Foundation. +@end enumerate + +@page +@unnumberedsec ADDENDUM: How to use this License for your documents + +To use this License in a document you have written, include a copy of +the License in the document and put the following copyright and +license notices just after the title page: + +@smallexample +@group + Copyright (C) @var{year} @var{your name}. + Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.2 + or any later version published by the Free Software Foundation; + with no Invariant Sections, no Front-Cover Texts, and no Back-Cover + Texts. A copy of the license is included in the section entitled ``GNU + Free Documentation License''. +@end group +@end smallexample + +If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, +replace the ``with...Texts.'' line with this: + +@smallexample +@group + with the Invariant Sections being @var{list their titles}, with + the Front-Cover Texts being @var{list}, and with the Back-Cover Texts + being @var{list}. +@end group +@end smallexample + +If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. + +If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of +free software license, such as the GNU General Public License, +to permit their use in free software. + +@c Local Variables: +@c ispell-local-pdict: "ispell-dict" +@c End: + +@c man end diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/funding.texi b/gcc-4.2.1-5666.3/gcc/doc/include/funding.texi new file mode 100644 index 000000000..d1583fabc --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/funding.texi @@ -0,0 +1,60 @@ +@ignore +@c Set file name and title for man page. +@setfilename fsf-funding +@settitle Funding Free Software +@c man begin SEEALSO +gpl(7), gfdl(7). +@c man end +@end ignore +@node Funding +@c man begin DESCRIPTION +@unnumbered Funding Free Software + +If you want to have more free software a few years from now, it makes +sense for you to help encourage people to contribute funds for its +development. The most effective approach known is to encourage +commercial redistributors to donate. + +Users of free software systems can boost the pace of development by +encouraging for-a-fee distributors to donate part of their selling price +to free software developers---the Free Software Foundation, and others. + +The way to convince distributors to do this is to demand it and expect +it from them. So when you compare distributors, judge them partly by +how much they give to free software development. Show distributors +they must compete to be the one who gives the most. + +To make this approach work, you must insist on numbers that you can +compare, such as, ``We will donate ten dollars to the Frobnitz project +for each disk sold.'' Don't be satisfied with a vague promise, such as +``A portion of the profits are donated,'' since it doesn't give a basis +for comparison. + +Even a precise fraction ``of the profits from this disk'' is not very +meaningful, since creative accounting and unrelated business decisions +can greatly alter what fraction of the sales price counts as profit. +If the price you pay is $50, ten percent of the profit is probably +less than a dollar; it might be a few cents, or nothing at all. + +Some redistributors do development work themselves. This is useful too; +but to keep everyone honest, you need to inquire how much they do, and +what kind. Some kinds of development make much more long-term +difference than others. For example, maintaining a separate version of +a program contributes very little; maintaining the standard version of a +program for the whole community contributes much. Easy new ports +contribute little, since someone else would surely do them; difficult +ports such as adding a new CPU to the GNU Compiler Collection contribute more; +major new features or packages contribute the most. + +By establishing the idea that supporting further development is ``the +proper thing to do'' when distributing free software for a fee, we can +assure a steady flow of resources into making more free software. +@c man end + +@display +@c man begin COPYRIGHT +Copyright @copyright{} 1994 Free Software Foundation, Inc. +Verbatim copying and redistribution of this section is permitted +without royalty; alteration is not permitted. +@c man end +@end display diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/gcc-common.texi b/gcc-4.2.1-5666.3/gcc/doc/include/gcc-common.texi new file mode 100644 index 000000000..bd44b3c2f --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/gcc-common.texi @@ -0,0 +1,69 @@ +@c Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c Version number and development mode. +@c version-GCC is @set to the base GCC version number. +@c DEVELOPMENT is @set for an in-development version, @clear for a +@c release version (corresponding to ``experimental''/anything else +@c in gcc/DEV-PHASE). + +@include gcc-vers.texi + +@c Common macros to support generating man pages: + +@macro gcctabopt{body} +@code{\body\} +@end macro +@macro gccoptlist{body} +@smallexample +\body\ +@end smallexample +@end macro +@c Makeinfo handles the above macro OK, TeX needs manual line breaks; +@c they get lost at some point in handling the macro. But if @macro is +@c used here rather than @alias, it produces double line breaks. +@iftex +@alias gol = * +@end iftex +@ifnottex +@macro gol +@end macro +@end ifnottex + +@c For FSF printing, define FSFPRINT. Also update the ISBN and last +@c printing date for the manual being printed. +@c @set FSFPRINT +@ifset FSFPRINT +@smallbook +@finalout +@c Cause even numbered pages to be printed on the left hand side of +@c the page and odd numbered pages to be printed on the right hand +@c side of the page. Using this, you can print on both sides of a +@c sheet of paper and have the text on the same part of the sheet. + +@c The text on right hand pages is pushed towards the right hand +@c margin and the text on left hand pages is pushed toward the left +@c hand margin. +@c (To provide the reverse effect, set bindingoffset to -0.75in.) +@tex +\global\bindingoffset=0.75in +\global\normaloffset =0.75in +@end tex +@end ifset + +@c Macro to generate a "For the N.N.N version" subtitle on the title +@c page of TeX documentation. This macro should be used in the +@c titlepage environment after the title and any other subtitles have +@c been placed, and before any authors are placed. +@macro versionsubtitle +@ifclear DEVELOPMENT +@subtitle For @sc{gcc} version @value{version-GCC} +@end ifclear +@ifset DEVELOPMENT +@subtitle For @sc{gcc} version @value{version-GCC} (pre-release) +@end ifset +@c Even if there are no authors, the second titlepage line should be +@c forced to the bottom of the page. +@vskip 0pt plus 1filll +@end macro diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/gpl.texi b/gcc-4.2.1-5666.3/gcc/doc/include/gpl.texi new file mode 100644 index 000000000..bcb553587 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/gpl.texi @@ -0,0 +1,410 @@ +@ignore +@c Set file name and title for man page. +@setfilename gpl +@settitle GNU General Public License +@c man begin SEEALSO +gfdl(7), fsf-funding(7). +@c man end +@c man begin COPYRIGHT +Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +@c man end +@end ignore +@node Copying +@c man begin DESCRIPTION +@unnumbered GNU GENERAL PUBLIC LICENSE +@center Version 2, June 1991 + +@c This file is intended to be included in another file. + +@display +Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +@end display + +@unnumberedsec Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software---to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Library General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + +@iftex +@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION +@end iftex +@ifnottex +@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION +@end ifnottex + +@enumerate 0 +@item +This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The ``Program'', below, +refers to any such program or work, and a ``work based on the Program'' +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term ``modification''.) Each licensee is addressed as ``you''. + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + +@item +You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + +@item +You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + +@enumerate a +@item +You must cause the modified files to carry prominent notices +stating that you changed the files and the date of any change. + +@item +You must cause any work that you distribute or publish, that in +whole or in part contains or is derived from the Program or any +part thereof, to be licensed as a whole at no charge to all third +parties under the terms of this License. + +@item +If the modified program normally reads commands interactively +when run, you must cause it, when started running for such +interactive use in the most ordinary way, to print or display an +announcement including an appropriate copyright notice and a +notice that there is no warranty (or else, saying that you provide +a warranty) and that users may redistribute the program under +these conditions, and telling the user how to view a copy of this +License. (Exception: if the Program itself is interactive but +does not normally print such an announcement, your work based on +the Program is not required to print an announcement.) +@end enumerate + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + +@item +You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + +@enumerate a +@item +Accompany it with the complete corresponding machine-readable +source code, which must be distributed under the terms of Sections +1 and 2 above on a medium customarily used for software interchange; or, + +@item +Accompany it with a written offer, valid for at least three +years, to give any third party, for a charge no more than your +cost of physically performing source distribution, a complete +machine-readable copy of the corresponding source code, to be +distributed under the terms of Sections 1 and 2 above on a medium +customarily used for software interchange; or, + +@item +Accompany it with the information you received as to the offer +to distribute corresponding source code. (This alternative is +allowed only for noncommercial distribution and only if you +received the program in object code or executable form with such +an offer, in accord with Subsection b above.) +@end enumerate + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + +@item +You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + +@item +You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + +@item +Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + +@item +If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + +@item +If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + +@item +The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and ``any +later version'', you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + +@item +If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + +@iftex +@heading NO WARRANTY +@end iftex +@ifnottex +@center NO WARRANTY +@end ifnottex + +@item +BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + +@item +IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. +@end enumerate + +@iftex +@heading END OF TERMS AND CONDITIONS +@end iftex +@ifnottex +@center END OF TERMS AND CONDITIONS +@end ifnottex + +@page +@unnumberedsec Appendix: How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the ``copyright'' line and a pointer to where the full notice is found. + +@smallexample +@var{one line to give the program's name and a brief idea of what it does.} +Copyright (C) @var{year} @var{name of author} + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA +@end smallexample + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + +@smallexample +Gnomovision version 69, Copyright (C) @var{year} @var{name of author} +Gnomovision comes with ABSOLUTELY NO WARRANTY; for details +type `show w'. +This is free software, and you are welcome to redistribute it +under certain conditions; type `show c' for details. +@end smallexample + +The hypothetical commands @samp{show w} and @samp{show c} should show +the appropriate parts of the General Public License. Of course, the +commands you use may be called something other than @samp{show w} and +@samp{show c}; they could even be mouse-clicks or menu items---whatever +suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a ``copyright disclaimer'' for the program, if +necessary. Here is a sample; alter the names: + +@example +Yoyodyne, Inc., hereby disclaims all copyright interest in the program +`Gnomovision' (which makes passes at compilers) written by James Hacker. + +@var{signature of Ty Coon}, 1 April 1989 +Ty Coon, President of Vice +@end example + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. +@c man end diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/sourcecode.texi b/gcc-4.2.1-5666.3/gcc/doc/include/sourcecode.texi new file mode 100644 index 000000000..2a7fb2f0d --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/sourcecode.texi @@ -0,0 +1,51 @@ +@c APPLE LOCAL file GPL compliance +@node Source Code +@unnumbered Source Code + +The source code for released versions of Apple's GCC is available at +@samp{http://www.opensource.apple.com/darwinsource/}, in +@samp{.tar.gz} format. + +For unreleased versions (including 'seeds', beta versions and +engineering roots), source can be obtained by asking the Apple contact +from which you obtained the unreleased version. + +For many versions of Apple's GCC, source code is available by using +anonymous Subversion. You may obtain Subversion ('SVN') from +@samp{http://subversion.tigris.org/project_packages.html}. + +Development of this version is done at +@samp{svn://gcc.gnu.org/svn/gcc/branches/apple-local-200502-branch}. + +For example, you can fetch the latest version by entering: + +@smallexample +$ svn co svn://gcc.gnu.org/svn/gcc/branches/apple-local-200502-branch +@end smallexample + +Each version will be tagged based on its build number, which +you can find by executing @samp{gcc --version}; for instance, if this prints + +@smallexample +gcc (GCC) 3.3 20030304 (Apple Computer, Inc. build 8402) +@end smallexample + +then the build number is 8402. Some older compilers may require you +use @samp{gcc -v} to obtain the build number. Once you have the build +number, its tag will be at +@samp{svn://gcc.gnu.org/svn/gcc/tags/apple}, like +@samp{svn://gcc.gnu.org/svn/gcc/tags/apple/gcc-8402}. You can list +all the tags by writing + +@smallexample +$ svn ls svn://gcc.gnu.org/svn/gcc/tags/apple +@end smallexample + +Then check out a particular version by writing + +@smallexample +$ svn co svn://gcc.gnu.org/svn/gcc/tags/apple/gcc-8402 +@end smallexample + +The above command won't succeed as written, because 8402 is not yet a +real compiler build number. diff --git a/gcc-4.2.1-5666.3/gcc/doc/include/texinfo.tex b/gcc-4.2.1-5666.3/gcc/doc/include/texinfo.tex new file mode 100644 index 000000000..96d45edb1 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/include/texinfo.tex @@ -0,0 +1,7235 @@ +% texinfo.tex -- TeX macros to handle Texinfo files. +% +% Load plain if necessary, i.e., if running under initex. +\expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi +% +\def\texinfoversion{2005-06-10.07} +% +% Copyright (C) 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995, +% 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software +% Foundation, Inc. +% +% This texinfo.tex file is free software; you can redistribute it and/or +% modify it under the terms of the GNU General Public License as +% published by the Free Software Foundation; either version 2, or (at +% your option) any later version. +% +% This texinfo.tex file is distributed in the hope that it will be +% useful, but WITHOUT ANY WARRANTY; without even the implied warranty +% of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +% General Public License for more details. +% +% You should have received a copy of the GNU General Public License +% along with this texinfo.tex file; see the file COPYING. If not, write +% to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +% Boston, MA 02110-1301, USA. +% +% As a special exception, when this file is read by TeX when processing +% a Texinfo source document, you may use the result without +% restriction. (This has been our intent since Texinfo was invented.) +% +% Please try the latest version of texinfo.tex before submitting bug +% reports; you can get the latest version from: +% http://www.gnu.org/software/texinfo/ (the Texinfo home page), or +% ftp://tug.org/tex/texinfo.tex +% (and all CTAN mirrors, see http://www.ctan.org). +% The texinfo.tex in any given distribution could well be out +% of date, so if that's what you're using, please check. +% +% Send bug reports to bug-texinfo@gnu.org. Please include including a +% complete document in each bug report with which we can reproduce the +% problem. Patches are, of course, greatly appreciated. +% +% To process a Texinfo manual with TeX, it's most reliable to use the +% texi2dvi shell script that comes with the distribution. For a simple +% manual foo.texi, however, you can get away with this: +% tex foo.texi +% texindex foo.?? +% tex foo.texi +% tex foo.texi +% dvips foo.dvi -o # or whatever; this makes foo.ps. +% The extra TeX runs get the cross-reference information correct. +% Sometimes one run after texindex suffices, and sometimes you need more +% than two; texi2dvi does it as many times as necessary. +% +% It is possible to adapt texinfo.tex for other languages, to some +% extent. You can get the existing language-specific files from the +% full Texinfo distribution. +% +% The GNU Texinfo home page is http://www.gnu.org/software/texinfo. + + +\message{Loading texinfo [version \texinfoversion]:} + +% If in a .fmt file, print the version number +% and turn on active characters that we couldn't do earlier because +% they might have appeared in the input file name. +\everyjob{\message{[Texinfo version \texinfoversion]}% + \catcode`+=\active \catcode`\_=\active} + +\message{Basics,} +\chardef\other=12 + +% We never want plain's \outer definition of \+ in Texinfo. +% For @tex, we can use \tabalign. +\let\+ = \relax + +% Save some plain tex macros whose names we will redefine. +\let\ptexb=\b +\let\ptexbullet=\bullet +\let\ptexc=\c +\let\ptexcomma=\, +\let\ptexdot=\. +\let\ptexdots=\dots +\let\ptexend=\end +\let\ptexequiv=\equiv +\let\ptexexclam=\! +\let\ptexfootnote=\footnote +\let\ptexgtr=> +\let\ptexhat=^ +\let\ptexi=\i +\let\ptexindent=\indent +\let\ptexinsert=\insert +\let\ptexlbrace=\{ +\let\ptexless=< +\let\ptexnewwrite\newwrite +\let\ptexnoindent=\noindent +\let\ptexplus=+ +\let\ptexrbrace=\} +\let\ptexslash=\/ +\let\ptexstar=\* +\let\ptext=\t + +% If this character appears in an error message or help string, it +% starts a new line in the output. +\newlinechar = `^^J + +% Use TeX 3.0's \inputlineno to get the line number, for better error +% messages, but if we're using an old version of TeX, don't do anything. +% +\ifx\inputlineno\thisisundefined + \let\linenumber = \empty % Pre-3.0. +\else + \def\linenumber{l.\the\inputlineno:\space} +\fi + +% Set up fixed words for English if not already set. +\ifx\putwordAppendix\undefined \gdef\putwordAppendix{Appendix}\fi +\ifx\putwordChapter\undefined \gdef\putwordChapter{Chapter}\fi +\ifx\putwordfile\undefined \gdef\putwordfile{file}\fi +\ifx\putwordin\undefined \gdef\putwordin{in}\fi +\ifx\putwordIndexIsEmpty\undefined \gdef\putwordIndexIsEmpty{(Index is empty)}\fi +\ifx\putwordIndexNonexistent\undefined \gdef\putwordIndexNonexistent{(Index is nonexistent)}\fi +\ifx\putwordInfo\undefined \gdef\putwordInfo{Info}\fi +\ifx\putwordInstanceVariableof\undefined \gdef\putwordInstanceVariableof{Instance Variable of}\fi +\ifx\putwordMethodon\undefined \gdef\putwordMethodon{Method on}\fi +\ifx\putwordNoTitle\undefined \gdef\putwordNoTitle{No Title}\fi +\ifx\putwordof\undefined \gdef\putwordof{of}\fi +\ifx\putwordon\undefined \gdef\putwordon{on}\fi +\ifx\putwordpage\undefined \gdef\putwordpage{page}\fi +\ifx\putwordsection\undefined \gdef\putwordsection{section}\fi +\ifx\putwordSection\undefined \gdef\putwordSection{Section}\fi +\ifx\putwordsee\undefined \gdef\putwordsee{see}\fi +\ifx\putwordSee\undefined \gdef\putwordSee{See}\fi +\ifx\putwordShortTOC\undefined \gdef\putwordShortTOC{Short Contents}\fi +\ifx\putwordTOC\undefined \gdef\putwordTOC{Table of Contents}\fi +% +\ifx\putwordMJan\undefined \gdef\putwordMJan{January}\fi +\ifx\putwordMFeb\undefined \gdef\putwordMFeb{February}\fi +\ifx\putwordMMar\undefined \gdef\putwordMMar{March}\fi +\ifx\putwordMApr\undefined \gdef\putwordMApr{April}\fi +\ifx\putwordMMay\undefined \gdef\putwordMMay{May}\fi +\ifx\putwordMJun\undefined \gdef\putwordMJun{June}\fi +\ifx\putwordMJul\undefined \gdef\putwordMJul{July}\fi +\ifx\putwordMAug\undefined \gdef\putwordMAug{August}\fi +\ifx\putwordMSep\undefined \gdef\putwordMSep{September}\fi +\ifx\putwordMOct\undefined \gdef\putwordMOct{October}\fi +\ifx\putwordMNov\undefined \gdef\putwordMNov{November}\fi +\ifx\putwordMDec\undefined \gdef\putwordMDec{December}\fi +% +\ifx\putwordDefmac\undefined \gdef\putwordDefmac{Macro}\fi +\ifx\putwordDefspec\undefined \gdef\putwordDefspec{Special Form}\fi +\ifx\putwordDefvar\undefined \gdef\putwordDefvar{Variable}\fi +\ifx\putwordDefopt\undefined \gdef\putwordDefopt{User Option}\fi +\ifx\putwordDeffunc\undefined \gdef\putwordDeffunc{Function}\fi + +% In some macros, we cannot use the `\? notation---the left quote is +% in some cases the escape char. +\chardef\backChar = `\\ +\chardef\colonChar = `\: +\chardef\commaChar = `\, +\chardef\dotChar = `\. +\chardef\exclamChar= `\! +\chardef\plusChar = `\+ +\chardef\questChar = `\? +\chardef\semiChar = `\; +\chardef\underChar = `\_ + +\chardef\spaceChar = `\ % +\chardef\spacecat = 10 +\def\spaceisspace{\catcode\spaceChar=\spacecat} + +{% for help with debugging. + % example usage: \expandafter\show\activebackslash + \catcode`\! = 0 \catcode`\\ = \active + !global!def!activebackslash{\} +} + +% Ignore a token. +% +\def\gobble#1{} + +% The following is used inside several \edef's. +\def\makecsname#1{\expandafter\noexpand\csname#1\endcsname} + +% Hyphenation fixes. +\hyphenation{ + Flor-i-da Ghost-script Ghost-view Mac-OS Post-Script + ap-pen-dix bit-map bit-maps + data-base data-bases eshell fall-ing half-way long-est man-u-script + man-u-scripts mini-buf-fer mini-buf-fers over-view par-a-digm + par-a-digms rath-er rec-tan-gu-lar ro-bot-ics se-vere-ly set-up spa-ces + spell-ing spell-ings + stand-alone strong-est time-stamp time-stamps which-ever white-space + wide-spread wrap-around +} + +% Margin to add to right of even pages, to left of odd pages. +\newdimen\bindingoffset +\newdimen\normaloffset +\newdimen\pagewidth \newdimen\pageheight + +% For a final copy, take out the rectangles +% that mark overfull boxes (in case you have decided +% that the text looks ok even though it passes the margin). +% +\def\finalout{\overfullrule=0pt} + +% @| inserts a changebar to the left of the current line. It should +% surround any changed text. This approach does *not* work if the +% change spans more than two lines of output. To handle that, we would +% have adopt a much more difficult approach (putting marks into the main +% vertical list for the beginning and end of each change). +% +\def\|{% + % \vadjust can only be used in horizontal mode. + \leavevmode + % + % Append this vertical mode material after the current line in the output. + \vadjust{% + % We want to insert a rule with the height and depth of the current + % leading; that is exactly what \strutbox is supposed to record. + \vskip-\baselineskip + % + % \vadjust-items are inserted at the left edge of the type. So + % the \llap here moves out into the left-hand margin. + \llap{% + % + % For a thicker or thinner bar, change the `1pt'. + \vrule height\baselineskip width1pt + % + % This is the space between the bar and the text. + \hskip 12pt + }% + }% +} + +% Sometimes it is convenient to have everything in the transcript file +% and nothing on the terminal. We don't just call \tracingall here, +% since that produces some useless output on the terminal. We also make +% some effort to order the tracing commands to reduce output in the log +% file; cf. trace.sty in LaTeX. +% +\def\gloggingall{\begingroup \globaldefs = 1 \loggingall \endgroup}% +\def\loggingall{% + \tracingstats2 + \tracingpages1 + \tracinglostchars2 % 2 gives us more in etex + \tracingparagraphs1 + \tracingoutput1 + \tracingmacros2 + \tracingrestores1 + \showboxbreadth\maxdimen \showboxdepth\maxdimen + \ifx\eTeXversion\undefined\else % etex gives us more logging + \tracingscantokens1 + \tracingifs1 + \tracinggroups1 + \tracingnesting2 + \tracingassigns1 + \fi + \tracingcommands3 % 3 gives us more in etex + \errorcontextlines16 +}% + +% add check for \lastpenalty to plain's definitions. If the last thing +% we did was a \nobreak, we don't want to insert more space. +% +\def\smallbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\smallskipamount + \removelastskip\penalty-50\smallskip\fi\fi} +\def\medbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\medskipamount + \removelastskip\penalty-100\medskip\fi\fi} +\def\bigbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\bigskipamount + \removelastskip\penalty-200\bigskip\fi\fi} + +% For @cropmarks command. +% Do @cropmarks to get crop marks. +% +\newif\ifcropmarks +\let\cropmarks = \cropmarkstrue +% +% Dimensions to add cropmarks at corners. +% Added by P. A. MacKay, 12 Nov. 1986 +% +\newdimen\outerhsize \newdimen\outervsize % set by the paper size routines +\newdimen\cornerlong \cornerlong=1pc +\newdimen\cornerthick \cornerthick=.3pt +\newdimen\topandbottommargin \topandbottommargin=.75in + +% Main output routine. +\chardef\PAGE = 255 +\output = {\onepageout{\pagecontents\PAGE}} + +\newbox\headlinebox +\newbox\footlinebox + +% \onepageout takes a vbox as an argument. Note that \pagecontents +% does insertions, but you have to call it yourself. +\def\onepageout#1{% + \ifcropmarks \hoffset=0pt \else \hoffset=\normaloffset \fi + % + \ifodd\pageno \advance\hoffset by \bindingoffset + \else \advance\hoffset by -\bindingoffset\fi + % + % Do this outside of the \shipout so @code etc. will be expanded in + % the headline as they should be, not taken literally (outputting ''code). + \setbox\headlinebox = \vbox{\let\hsize=\pagewidth \makeheadline}% + \setbox\footlinebox = \vbox{\let\hsize=\pagewidth \makefootline}% + % + {% + % Have to do this stuff outside the \shipout because we want it to + % take effect in \write's, yet the group defined by the \vbox ends + % before the \shipout runs. + % + \escapechar = `\\ % use backslash in output files. + \indexdummies % don't expand commands in the output. + \normalturnoffactive % \ in index entries must not stay \, e.g., if + % the page break happens to be in the middle of an example. + \shipout\vbox{% + % Do this early so pdf references go to the beginning of the page. + \ifpdfmakepagedest \pdfdest name{\the\pageno} xyz\fi + % + \ifcropmarks \vbox to \outervsize\bgroup + \hsize = \outerhsize + \vskip-\topandbottommargin + \vtop to0pt{% + \line{\ewtop\hfil\ewtop}% + \nointerlineskip + \line{% + \vbox{\moveleft\cornerthick\nstop}% + \hfill + \vbox{\moveright\cornerthick\nstop}% + }% + \vss}% + \vskip\topandbottommargin + \line\bgroup + \hfil % center the page within the outer (page) hsize. + \ifodd\pageno\hskip\bindingoffset\fi + \vbox\bgroup + \fi + % + \unvbox\headlinebox + \pagebody{#1}% + \ifdim\ht\footlinebox > 0pt + % Only leave this space if the footline is nonempty. + % (We lessened \vsize for it in \oddfootingxxx.) + % The \baselineskip=24pt in plain's \makefootline has no effect. + \vskip 2\baselineskip + \unvbox\footlinebox + \fi + % + \ifcropmarks + \egroup % end of \vbox\bgroup + \hfil\egroup % end of (centering) \line\bgroup + \vskip\topandbottommargin plus1fill minus1fill + \boxmaxdepth = \cornerthick + \vbox to0pt{\vss + \line{% + \vbox{\moveleft\cornerthick\nsbot}% + \hfill + \vbox{\moveright\cornerthick\nsbot}% + }% + \nointerlineskip + \line{\ewbot\hfil\ewbot}% + }% + \egroup % \vbox from first cropmarks clause + \fi + }% end of \shipout\vbox + }% end of group with \normalturnoffactive + \advancepageno + \ifnum\outputpenalty>-20000 \else\dosupereject\fi +} + +\newinsert\margin \dimen\margin=\maxdimen + +\def\pagebody#1{\vbox to\pageheight{\boxmaxdepth=\maxdepth #1}} +{\catcode`\@ =11 +\gdef\pagecontents#1{\ifvoid\topins\else\unvbox\topins\fi +% marginal hacks, juha@viisa.uucp (Juha Takala) +\ifvoid\margin\else % marginal info is present + \rlap{\kern\hsize\vbox to\z@{\kern1pt\box\margin \vss}}\fi +\dimen@=\dp#1 \unvbox#1 +\ifvoid\footins\else\vskip\skip\footins\footnoterule \unvbox\footins\fi +\ifr@ggedbottom \kern-\dimen@ \vfil \fi} +} + +% Here are the rules for the cropmarks. Note that they are +% offset so that the space between them is truly \outerhsize or \outervsize +% (P. A. MacKay, 12 November, 1986) +% +\def\ewtop{\vrule height\cornerthick depth0pt width\cornerlong} +\def\nstop{\vbox + {\hrule height\cornerthick depth\cornerlong width\cornerthick}} +\def\ewbot{\vrule height0pt depth\cornerthick width\cornerlong} +\def\nsbot{\vbox + {\hrule height\cornerlong depth\cornerthick width\cornerthick}} + +% Parse an argument, then pass it to #1. The argument is the rest of +% the input line (except we remove a trailing comment). #1 should be a +% macro which expects an ordinary undelimited TeX argument. +% +\def\parsearg{\parseargusing{}} +\def\parseargusing#1#2{% + \def\next{#2}% + \begingroup + \obeylines + \spaceisspace + #1% + \parseargline\empty% Insert the \empty token, see \finishparsearg below. +} + +{\obeylines % + \gdef\parseargline#1^^M{% + \endgroup % End of the group started in \parsearg. + \argremovecomment #1\comment\ArgTerm% + }% +} + +% First remove any @comment, then any @c comment. +\def\argremovecomment#1\comment#2\ArgTerm{\argremovec #1\c\ArgTerm} +\def\argremovec#1\c#2\ArgTerm{\argcheckspaces#1\^^M\ArgTerm} + +% Each occurence of `\^^M' or `<space>\^^M' is replaced by a single space. +% +% \argremovec might leave us with trailing space, e.g., +% @end itemize @c foo +% This space token undergoes the same procedure and is eventually removed +% by \finishparsearg. +% +\def\argcheckspaces#1\^^M{\argcheckspacesX#1\^^M \^^M} +\def\argcheckspacesX#1 \^^M{\argcheckspacesY#1\^^M} +\def\argcheckspacesY#1\^^M#2\^^M#3\ArgTerm{% + \def\temp{#3}% + \ifx\temp\empty + % We cannot use \next here, as it holds the macro to run; + % thus we reuse \temp. + \let\temp\finishparsearg + \else + \let\temp\argcheckspaces + \fi + % Put the space token in: + \temp#1 #3\ArgTerm +} + +% If a _delimited_ argument is enclosed in braces, they get stripped; so +% to get _exactly_ the rest of the line, we had to prevent such situation. +% We prepended an \empty token at the very beginning and we expand it now, +% just before passing the control to \next. +% (Similarily, we have to think about #3 of \argcheckspacesY above: it is +% either the null string, or it ends with \^^M---thus there is no danger +% that a pair of braces would be stripped. +% +% But first, we have to remove the trailing space token. +% +\def\finishparsearg#1 \ArgTerm{\expandafter\next\expandafter{#1}} + +% \parseargdef\foo{...} +% is roughly equivalent to +% \def\foo{\parsearg\Xfoo} +% \def\Xfoo#1{...} +% +% Actually, I use \csname\string\foo\endcsname, ie. \\foo, as it is my +% favourite TeX trick. --kasal, 16nov03 + +\def\parseargdef#1{% + \expandafter \doparseargdef \csname\string#1\endcsname #1% +} +\def\doparseargdef#1#2{% + \def#2{\parsearg#1}% + \def#1##1% +} + +% Several utility definitions with active space: +{ + \obeyspaces + \gdef\obeyedspace{ } + + % Make each space character in the input produce a normal interword + % space in the output. Don't allow a line break at this space, as this + % is used only in environments like @example, where each line of input + % should produce a line of output anyway. + % + \gdef\sepspaces{\obeyspaces\let =\tie} + + % If an index command is used in an @example environment, any spaces + % therein should become regular spaces in the raw index file, not the + % expansion of \tie (\leavevmode \penalty \@M \ ). + \gdef\unsepspaces{\let =\space} +} + + +\def\flushcr{\ifx\par\lisppar \def\next##1{}\else \let\next=\relax \fi \next} + +% Define the framework for environments in texinfo.tex. It's used like this: +% +% \envdef\foo{...} +% \def\Efoo{...} +% +% It's the responsibility of \envdef to insert \begingroup before the +% actual body; @end closes the group after calling \Efoo. \envdef also +% defines \thisenv, so the current environment is known; @end checks +% whether the environment name matches. The \checkenv macro can also be +% used to check whether the current environment is the one expected. +% +% Non-false conditionals (@iftex, @ifset) don't fit into this, so they +% are not treated as enviroments; they don't open a group. (The +% implementation of @end takes care not to call \endgroup in this +% special case.) + + +% At runtime, environments start with this: +\def\startenvironment#1{\begingroup\def\thisenv{#1}} +% initialize +\let\thisenv\empty + +% ... but they get defined via ``\envdef\foo{...}'': +\long\def\envdef#1#2{\def#1{\startenvironment#1#2}} +\def\envparseargdef#1#2{\parseargdef#1{\startenvironment#1#2}} + +% Check whether we're in the right environment: +\def\checkenv#1{% + \def\temp{#1}% + \ifx\thisenv\temp + \else + \badenverr + \fi +} + +% Evironment mismatch, #1 expected: +\def\badenverr{% + \errhelp = \EMsimple + \errmessage{This command can appear only \inenvironment\temp, + not \inenvironment\thisenv}% +} +\def\inenvironment#1{% + \ifx#1\empty + out of any environment% + \else + in environment \expandafter\string#1% + \fi +} + +% @end foo executes the definition of \Efoo. +% But first, it executes a specialized version of \checkenv +% +\parseargdef\end{% + \if 1\csname iscond.#1\endcsname + \else + % The general wording of \badenverr may not be ideal, but... --kasal, 06nov03 + \expandafter\checkenv\csname#1\endcsname + \csname E#1\endcsname + \endgroup + \fi +} + +\newhelp\EMsimple{Press RETURN to continue.} + + +%% Simple single-character @ commands + +% @@ prints an @ +% Kludge this until the fonts are right (grr). +\def\@{{\tt\char64}} + +% This is turned off because it was never documented +% and you can use @w{...} around a quote to suppress ligatures. +%% Define @` and @' to be the same as ` and ' +%% but suppressing ligatures. +%\def\`{{`}} +%\def\'{{'}} + +% Used to generate quoted braces. +\def\mylbrace {{\tt\char123}} +\def\myrbrace {{\tt\char125}} +\let\{=\mylbrace +\let\}=\myrbrace +\begingroup + % Definitions to produce \{ and \} commands for indices, + % and @{ and @} for the aux/toc files. + \catcode`\{ = \other \catcode`\} = \other + \catcode`\[ = 1 \catcode`\] = 2 + \catcode`\! = 0 \catcode`\\ = \other + !gdef!lbracecmd[\{]% + !gdef!rbracecmd[\}]% + !gdef!lbraceatcmd[@{]% + !gdef!rbraceatcmd[@}]% +!endgroup + +% @comma{} to avoid , parsing problems. +\let\comma = , + +% Accents: @, @dotaccent @ringaccent @ubaraccent @udotaccent +% Others are defined by plain TeX: @` @' @" @^ @~ @= @u @v @H. +\let\, = \c +\let\dotaccent = \. +\def\ringaccent#1{{\accent23 #1}} +\let\tieaccent = \t +\let\ubaraccent = \b +\let\udotaccent = \d + +% Other special characters: @questiondown @exclamdown @ordf @ordm +% Plain TeX defines: @AA @AE @O @OE @L (plus lowercase versions) @ss. +\def\questiondown{?`} +\def\exclamdown{!`} +\def\ordf{\leavevmode\raise1ex\hbox{\selectfonts\lllsize \underbar{a}}} +\def\ordm{\leavevmode\raise1ex\hbox{\selectfonts\lllsize \underbar{o}}} + +% Dotless i and dotless j, used for accents. +\def\imacro{i} +\def\jmacro{j} +\def\dotless#1{% + \def\temp{#1}% + \ifx\temp\imacro \ptexi + \else\ifx\temp\jmacro \j + \else \errmessage{@dotless can be used only with i or j}% + \fi\fi +} + +% The \TeX{} logo, as in plain, but resetting the spacing so that a +% period following counts as ending a sentence. (Idea found in latex.) +% +\edef\TeX{\TeX \spacefactor=1000 } + +% @LaTeX{} logo. Not quite the same results as the definition in +% latex.ltx, since we use a different font for the raised A; it's most +% convenient for us to use an explicitly smaller font, rather than using +% the \scriptstyle font (since we don't reset \scriptstyle and +% \scriptscriptstyle). +% +\def\LaTeX{% + L\kern-.36em + {\setbox0=\hbox{T}% + \vbox to \ht0{\hbox{\selectfonts\lllsize A}\vss}}% + \kern-.15em + \TeX +} + +% Be sure we're in horizontal mode when doing a tie, since we make space +% equivalent to this in @example-like environments. Otherwise, a space +% at the beginning of a line will start with \penalty -- and +% since \penalty is valid in vertical mode, we'd end up putting the +% penalty on the vertical list instead of in the new paragraph. +{\catcode`@ = 11 + % Avoid using \@M directly, because that causes trouble + % if the definition is written into an index file. + \global\let\tiepenalty = \@M + \gdef\tie{\leavevmode\penalty\tiepenalty\ } +} + +% @: forces normal size whitespace following. +\def\:{\spacefactor=1000 } + +% @* forces a line break. +\def\*{\hfil\break\hbox{}\ignorespaces} + +% @/ allows a line break. +\let\/=\allowbreak + +% @. is an end-of-sentence period. +\def\.{.\spacefactor=\endofsentencespacefactor\space} + +% @! is an end-of-sentence bang. +\def\!{!\spacefactor=\endofsentencespacefactor\space} + +% @? is an end-of-sentence query. +\def\?{?\spacefactor=\endofsentencespacefactor\space} + +% @frenchspacing on|off says whether to put extra space after punctuation. +% +\def\onword{on} +\def\offword{off} +% +\parseargdef\frenchspacing{% + \def\temp{#1}% + \ifx\temp\onword \plainfrenchspacing + \else\ifx\temp\offword \plainnonfrenchspacing + \else + \errhelp = \EMsimple + \errmessage{Unknown @frenchspacing option `\temp', must be on/off}% + \fi\fi +} + +% @w prevents a word break. Without the \leavevmode, @w at the +% beginning of a paragraph, when TeX is still in vertical mode, would +% produce a whole line of output instead of starting the paragraph. +\def\w#1{\leavevmode\hbox{#1}} + +% @group ... @end group forces ... to be all on one page, by enclosing +% it in a TeX vbox. We use \vtop instead of \vbox to construct the box +% to keep its height that of a normal line. According to the rules for +% \topskip (p.114 of the TeXbook), the glue inserted is +% max (\topskip - \ht (first item), 0). If that height is large, +% therefore, no glue is inserted, and the space between the headline and +% the text is small, which looks bad. +% +% Another complication is that the group might be very large. This can +% cause the glue on the previous page to be unduly stretched, because it +% does not have much material. In this case, it's better to add an +% explicit \vfill so that the extra space is at the bottom. The +% threshold for doing this is if the group is more than \vfilllimit +% percent of a page (\vfilllimit can be changed inside of @tex). +% +\newbox\groupbox +\def\vfilllimit{0.7} +% +\envdef\group{% + \ifnum\catcode`\^^M=\active \else + \errhelp = \groupinvalidhelp + \errmessage{@group invalid in context where filling is enabled}% + \fi + \startsavinginserts + % + \setbox\groupbox = \vtop\bgroup + % Do @comment since we are called inside an environment such as + % @example, where each end-of-line in the input causes an + % end-of-line in the output. We don't want the end-of-line after + % the `@group' to put extra space in the output. Since @group + % should appear on a line by itself (according to the Texinfo + % manual), we don't worry about eating any user text. + \comment +} +% +% The \vtop produces a box with normal height and large depth; thus, TeX puts +% \baselineskip glue before it, and (when the next line of text is done) +% \lineskip glue after it. Thus, space below is not quite equal to space +% above. But it's pretty close. +\def\Egroup{% + % To get correct interline space between the last line of the group + % and the first line afterwards, we have to propagate \prevdepth. + \endgraf % Not \par, as it may have been set to \lisppar. + \global\dimen1 = \prevdepth + \egroup % End the \vtop. + % \dimen0 is the vertical size of the group's box. + \dimen0 = \ht\groupbox \advance\dimen0 by \dp\groupbox + % \dimen2 is how much space is left on the page (more or less). + \dimen2 = \pageheight \advance\dimen2 by -\pagetotal + % if the group doesn't fit on the current page, and it's a big big + % group, force a page break. + \ifdim \dimen0 > \dimen2 + \ifdim \pagetotal < \vfilllimit\pageheight + \page + \fi + \fi + \box\groupbox + \prevdepth = \dimen1 + \checkinserts +} +% +% TeX puts in an \escapechar (i.e., `@') at the beginning of the help +% message, so this ends up printing `@group can only ...'. +% +\newhelp\groupinvalidhelp{% +group can only be used in environments such as @example,^^J% +where each line of input produces a line of output.} + +% @need space-in-mils +% forces a page break if there is not space-in-mils remaining. + +\newdimen\mil \mil=0.001in + +% Old definition--didn't work. +%\parseargdef\need{\par % +%% This method tries to make TeX break the page naturally +%% if the depth of the box does not fit. +%{\baselineskip=0pt% +%\vtop to #1\mil{\vfil}\kern -#1\mil\nobreak +%\prevdepth=-1000pt +%}} + +\parseargdef\need{% + % Ensure vertical mode, so we don't make a big box in the middle of a + % paragraph. + \par + % + % If the @need value is less than one line space, it's useless. + \dimen0 = #1\mil + \dimen2 = \ht\strutbox + \advance\dimen2 by \dp\strutbox + \ifdim\dimen0 > \dimen2 + % + % Do a \strut just to make the height of this box be normal, so the + % normal leading is inserted relative to the preceding line. + % And a page break here is fine. + \vtop to #1\mil{\strut\vfil}% + % + % TeX does not even consider page breaks if a penalty added to the + % main vertical list is 10000 or more. But in order to see if the + % empty box we just added fits on the page, we must make it consider + % page breaks. On the other hand, we don't want to actually break the + % page after the empty box. So we use a penalty of 9999. + % + % There is an extremely small chance that TeX will actually break the + % page at this \penalty, if there are no other feasible breakpoints in + % sight. (If the user is using lots of big @group commands, which + % almost-but-not-quite fill up a page, TeX will have a hard time doing + % good page breaking, for example.) However, I could not construct an + % example where a page broke at this \penalty; if it happens in a real + % document, then we can reconsider our strategy. + \penalty9999 + % + % Back up by the size of the box, whether we did a page break or not. + \kern -#1\mil + % + % Do not allow a page break right after this kern. + \nobreak + \fi +} + +% @br forces paragraph break (and is undocumented). + +\let\br = \par + +% @page forces the start of a new page. +% +\def\page{\par\vfill\supereject} + +% @exdent text.... +% outputs text on separate line in roman font, starting at standard page margin + +% This records the amount of indent in the innermost environment. +% That's how much \exdent should take out. +\newskip\exdentamount + +% This defn is used inside fill environments such as @defun. +\parseargdef\exdent{\hfil\break\hbox{\kern -\exdentamount{\rm#1}}\hfil\break} + +% This defn is used inside nofill environments such as @example. +\parseargdef\nofillexdent{{\advance \leftskip by -\exdentamount + \leftline{\hskip\leftskip{\rm#1}}}} + +% @inmargin{WHICH}{TEXT} puts TEXT in the WHICH margin next to the current +% paragraph. For more general purposes, use the \margin insertion +% class. WHICH is `l' or `r'. +% +\newskip\inmarginspacing \inmarginspacing=1cm +\def\strutdepth{\dp\strutbox} +% +\def\doinmargin#1#2{\strut\vadjust{% + \nobreak + \kern-\strutdepth + \vtop to \strutdepth{% + \baselineskip=\strutdepth + \vss + % if you have multiple lines of stuff to put here, you'll need to + % make the vbox yourself of the appropriate size. + \ifx#1l% + \llap{\ignorespaces #2\hskip\inmarginspacing}% + \else + \rlap{\hskip\hsize \hskip\inmarginspacing \ignorespaces #2}% + \fi + \null + }% +}} +\def\inleftmargin{\doinmargin l} +\def\inrightmargin{\doinmargin r} +% +% @inmargin{TEXT [, RIGHT-TEXT]} +% (if RIGHT-TEXT is given, use TEXT for left page, RIGHT-TEXT for right; +% else use TEXT for both). +% +\def\inmargin#1{\parseinmargin #1,,\finish} +\def\parseinmargin#1,#2,#3\finish{% not perfect, but better than nothing. + \setbox0 = \hbox{\ignorespaces #2}% + \ifdim\wd0 > 0pt + \def\lefttext{#1}% have both texts + \def\righttext{#2}% + \else + \def\lefttext{#1}% have only one text + \def\righttext{#1}% + \fi + % + \ifodd\pageno + \def\temp{\inrightmargin\righttext}% odd page -> outside is right margin + \else + \def\temp{\inleftmargin\lefttext}% + \fi + \temp +} + +% @include file insert text of that file as input. +% +\def\include{\parseargusing\filenamecatcodes\includezzz} +\def\includezzz#1{% + \pushthisfilestack + \def\thisfile{#1}% + {% + \makevalueexpandable + \def\temp{\input #1 }% + \expandafter + }\temp + \popthisfilestack +} +\def\filenamecatcodes{% + \catcode`\\=\other + \catcode`~=\other + \catcode`^=\other + \catcode`_=\other + \catcode`|=\other + \catcode`<=\other + \catcode`>=\other + \catcode`+=\other + \catcode`-=\other +} + +\def\pushthisfilestack{% + \expandafter\pushthisfilestackX\popthisfilestack\StackTerm +} +\def\pushthisfilestackX{% + \expandafter\pushthisfilestackY\thisfile\StackTerm +} +\def\pushthisfilestackY #1\StackTerm #2\StackTerm {% + \gdef\popthisfilestack{\gdef\thisfile{#1}\gdef\popthisfilestack{#2}}% +} + +\def\popthisfilestack{\errthisfilestackempty} +\def\errthisfilestackempty{\errmessage{Internal error: + the stack of filenames is empty.}} + +\def\thisfile{} + +% @center line +% outputs that line, centered. +% +\parseargdef\center{% + \ifhmode + \let\next\centerH + \else + \let\next\centerV + \fi + \next{\hfil \ignorespaces#1\unskip \hfil}% +} +\def\centerH#1{% + {% + \hfil\break + \advance\hsize by -\leftskip + \advance\hsize by -\rightskip + \line{#1}% + \break + }% +} +\def\centerV#1{\line{\kern\leftskip #1\kern\rightskip}} + +% @sp n outputs n lines of vertical space + +\parseargdef\sp{\vskip #1\baselineskip} + +% @comment ...line which is ignored... +% @c is the same as @comment +% @ignore ... @end ignore is another way to write a comment + +\def\comment{\begingroup \catcode`\^^M=\other% +\catcode`\@=\other \catcode`\{=\other \catcode`\}=\other% +\commentxxx} +{\catcode`\^^M=\other \gdef\commentxxx#1^^M{\endgroup}} + +\let\c=\comment + +% @paragraphindent NCHARS +% We'll use ems for NCHARS, close enough. +% NCHARS can also be the word `asis' or `none'. +% We cannot feasibly implement @paragraphindent asis, though. +% +\def\asisword{asis} % no translation, these are keywords +\def\noneword{none} +% +\parseargdef\paragraphindent{% + \def\temp{#1}% + \ifx\temp\asisword + \else + \ifx\temp\noneword + \defaultparindent = 0pt + \else + \defaultparindent = #1em + \fi + \fi + \parindent = \defaultparindent +} + +% @exampleindent NCHARS +% We'll use ems for NCHARS like @paragraphindent. +% It seems @exampleindent asis isn't necessary, but +% I preserve it to make it similar to @paragraphindent. +\parseargdef\exampleindent{% + \def\temp{#1}% + \ifx\temp\asisword + \else + \ifx\temp\noneword + \lispnarrowing = 0pt + \else + \lispnarrowing = #1em + \fi + \fi +} + +% @firstparagraphindent WORD +% If WORD is `none', then suppress indentation of the first paragraph +% after a section heading. If WORD is `insert', then do indent at such +% paragraphs. +% +% The paragraph indentation is suppressed or not by calling +% \suppressfirstparagraphindent, which the sectioning commands do. +% We switch the definition of this back and forth according to WORD. +% By default, we suppress indentation. +% +\def\suppressfirstparagraphindent{\dosuppressfirstparagraphindent} +\def\insertword{insert} +% +\parseargdef\firstparagraphindent{% + \def\temp{#1}% + \ifx\temp\noneword + \let\suppressfirstparagraphindent = \dosuppressfirstparagraphindent + \else\ifx\temp\insertword + \let\suppressfirstparagraphindent = \relax + \else + \errhelp = \EMsimple + \errmessage{Unknown @firstparagraphindent option `\temp'}% + \fi\fi +} + +% Here is how we actually suppress indentation. Redefine \everypar to +% \kern backwards by \parindent, and then reset itself to empty. +% +% We also make \indent itself not actually do anything until the next +% paragraph. +% +\gdef\dosuppressfirstparagraphindent{% + \gdef\indent{% + \restorefirstparagraphindent + \indent + }% + \gdef\noindent{% + \restorefirstparagraphindent + \noindent + }% + \global\everypar = {% + \kern -\parindent + \restorefirstparagraphindent + }% +} + +\gdef\restorefirstparagraphindent{% + \global \let \indent = \ptexindent + \global \let \noindent = \ptexnoindent + \global \everypar = {}% +} + + +% @asis just yields its argument. Used with @table, for example. +% +\def\asis#1{#1} + +% @math outputs its argument in math mode. +% +% One complication: _ usually means subscripts, but it could also mean +% an actual _ character, as in @math{@var{some_variable} + 1}. So make +% _ active, and distinguish by seeing if the current family is \slfam, +% which is what @var uses. +{ + \catcode\underChar = \active + \gdef\mathunderscore{% + \catcode\underChar=\active + \def_{\ifnum\fam=\slfam \_\else\sb\fi}% + } +} +% Another complication: we want \\ (and @\) to output a \ character. +% FYI, plain.tex uses \\ as a temporary control sequence (why?), but +% this is not advertised and we don't care. Texinfo does not +% otherwise define @\. +% +% The \mathchar is class=0=ordinary, family=7=ttfam, position=5C=\. +\def\mathbackslash{\ifnum\fam=\ttfam \mathchar"075C \else\backslash \fi} +% +\def\math{% + \tex + \mathunderscore + \let\\ = \mathbackslash + \mathactive + $\finishmath +} +\def\finishmath#1{#1$\endgroup} % Close the group opened by \tex. + +% Some active characters (such as <) are spaced differently in math. +% We have to reset their definitions in case the @math was an argument +% to a command which sets the catcodes (such as @item or @section). +% +{ + \catcode`^ = \active + \catcode`< = \active + \catcode`> = \active + \catcode`+ = \active + \gdef\mathactive{% + \let^ = \ptexhat + \let< = \ptexless + \let> = \ptexgtr + \let+ = \ptexplus + } +} + +% @bullet and @minus need the same treatment as @math, just above. +\def\bullet{$\ptexbullet$} +\def\minus{$-$} + +% @dots{} outputs an ellipsis using the current font. +% We do .5em per period so that it has the same spacing in a typewriter +% font as three actual period characters. +% +\def\dots{% + \leavevmode + \hbox to 1.5em{% + \hskip 0pt plus 0.25fil + .\hfil.\hfil.% + \hskip 0pt plus 0.5fil + }% +} + +% @enddots{} is an end-of-sentence ellipsis. +% +\def\enddots{% + \dots + \spacefactor=\endofsentencespacefactor +} + +% @comma{} is so commas can be inserted into text without messing up +% Texinfo's parsing. +% +\let\comma = , + +% @refill is a no-op. +\let\refill=\relax + +% If working on a large document in chapters, it is convenient to +% be able to disable indexing, cross-referencing, and contents, for test runs. +% This is done with @novalidate (before @setfilename). +% +\newif\iflinks \linkstrue % by default we want the aux files. +\let\novalidate = \linksfalse + +% @setfilename is done at the beginning of every texinfo file. +% So open here the files we need to have open while reading the input. +% This makes it possible to make a .fmt file for texinfo. +\def\setfilename{% + \fixbackslash % Turn off hack to swallow `\input texinfo'. + \iflinks + \tryauxfile + % Open the new aux file. TeX will close it automatically at exit. + \immediate\openout\auxfile=\jobname.aux + \fi % \openindices needs to do some work in any case. + \openindices + \let\setfilename=\comment % Ignore extra @setfilename cmds. + % + % If texinfo.cnf is present on the system, read it. + % Useful for site-wide @afourpaper, etc. + \openin 1 texinfo.cnf + \ifeof 1 \else \input texinfo.cnf \fi + \closein 1 + % + \comment % Ignore the actual filename. +} + +% Called from \setfilename. +% +\def\openindices{% + \newindex{cp}% + \newcodeindex{fn}% + \newcodeindex{vr}% + \newcodeindex{tp}% + \newcodeindex{ky}% + \newcodeindex{pg}% +} + +% @bye. +\outer\def\bye{\pagealignmacro\tracingstats=1\ptexend} + + +\message{pdf,} +% adobe `portable' document format +\newcount\tempnum +\newcount\lnkcount +\newtoks\filename +\newcount\filenamelength +\newcount\pgn +\newtoks\toksA +\newtoks\toksB +\newtoks\toksC +\newtoks\toksD +\newbox\boxA +\newcount\countA +\newif\ifpdf +\newif\ifpdfmakepagedest + +% when pdftex is run in dvi mode, \pdfoutput is defined (so \pdfoutput=1 +% can be set). So we test for \relax and 0 as well as \undefined, +% borrowed from ifpdf.sty. +\ifx\pdfoutput\undefined +\else + \ifx\pdfoutput\relax + \else + \ifcase\pdfoutput + \else + \pdftrue + \fi + \fi +\fi + +% PDF uses PostScript string constants for the names of xref targets, to +% for display in the outlines, and in other places. Thus, we have to +% double any backslashes. Otherwise, a name like "\node" will be +% interpreted as a newline (\n), followed by o, d, e. Not good. +% http://www.ntg.nl/pipermail/ntg-pdftex/2004-July/000654.html +% (and related messages, the final outcome is that it is up to the TeX +% user to double the backslashes and otherwise make the string valid, so +% that's we do). + +% double active backslashes. +% +{\catcode`\@=0 \catcode`\\=\active + @gdef@activebackslash{@catcode`@\=@active @otherbackslash} + @gdef@activebackslashdouble{% + @catcode@backChar=@active + @let\=@doublebackslash} +} + +% To handle parens, we must adopt a different approach, since parens are +% not active characters. hyperref.dtx (which has the same problem as +% us) handles it with this amazing macro to replace tokens. I've +% tinkered with it a little for texinfo, but it's definitely from there. +% +% #1 is the tokens to replace. +% #2 is the replacement. +% #3 is the control sequence with the string. +% +\def\HyPsdSubst#1#2#3{% + \def\HyPsdReplace##1#1##2\END{% + ##1% + \ifx\\##2\\% + \else + #2% + \HyReturnAfterFi{% + \HyPsdReplace##2\END + }% + \fi + }% + \xdef#3{\expandafter\HyPsdReplace#3#1\END}% +} +\long\def\HyReturnAfterFi#1\fi{\fi#1} + +% #1 is a control sequence in which to do the replacements. +\def\backslashparens#1{% + \xdef#1{#1}% redefine it as its expansion; the definition is simply + % \lastnode when called from \setref -> \pdfmkdest. + \HyPsdSubst{(}{\backslashlparen}{#1}% + \HyPsdSubst{)}{\backslashrparen}{#1}% +} + +{\catcode\exclamChar = 0 \catcode\backChar = \other + !gdef!backslashlparen{\(}% + !gdef!backslashrparen{\)}% +} + +\ifpdf + \input pdfcolor + \pdfcatalog{/PageMode /UseOutlines}% + \def\dopdfimage#1#2#3{% + \def\imagewidth{#2}% + \def\imageheight{#3}% + % without \immediate, pdftex seg faults when the same image is + % included twice. (Version 3.14159-pre-1.0-unofficial-20010704.) + \ifnum\pdftexversion < 14 + \immediate\pdfimage + \else + \immediate\pdfximage + \fi + \ifx\empty\imagewidth\else width \imagewidth \fi + \ifx\empty\imageheight\else height \imageheight \fi + \ifnum\pdftexversion<13 + #1.pdf% + \else + {#1.pdf}% + \fi + \ifnum\pdftexversion < 14 \else + \pdfrefximage \pdflastximage + \fi} + \def\pdfmkdest#1{{% + % We have to set dummies so commands such as @code, and characters + % such as \, aren't expanded when present in a section title. + \atdummies + \turnoffactive + \activebackslashdouble + \def\pdfdestname{#1}% + \backslashparens\pdfdestname + \pdfdest name{\pdfdestname} xyz% + }}% + % + % used to mark target names; must be expandable. + \def\pdfmkpgn#1{#1}% + % + \let\linkcolor = \Blue % was Cyan, but that seems light? + \def\endlink{\Black\pdfendlink} + % Adding outlines to PDF; macros for calculating structure of outlines + % come from Petr Olsak + \def\expnumber#1{\expandafter\ifx\csname#1\endcsname\relax 0% + \else \csname#1\endcsname \fi} + \def\advancenumber#1{\tempnum=\expnumber{#1}\relax + \advance\tempnum by 1 + \expandafter\xdef\csname#1\endcsname{\the\tempnum}} + % + % #1 is the section text, which is what will be displayed in the + % outline by the pdf viewer. #2 is the pdf expression for the number + % of subentries (or empty, for subsubsections). #3 is the node text, + % which might be empty if this toc entry had no corresponding node. + % #4 is the page number + % + \def\dopdfoutline#1#2#3#4{% + % Generate a link to the node text if that exists; else, use the + % page number. We could generate a destination for the section + % text in the case where a section has no node, but it doesn't + % seem worth the trouble, since most documents are normally structured. + \def\pdfoutlinedest{#3}% + \ifx\pdfoutlinedest\empty + \def\pdfoutlinedest{#4}% + \else + % Doubled backslashes in the name. + {\activebackslashdouble \xdef\pdfoutlinedest{#3}% + \backslashparens\pdfoutlinedest}% + \fi + % + % Also double the backslashes in the display string. + {\activebackslashdouble \xdef\pdfoutlinetext{#1}% + \backslashparens\pdfoutlinetext}% + % + \pdfoutline goto name{\pdfmkpgn{\pdfoutlinedest}}#2{\pdfoutlinetext}% + } + % + \def\pdfmakeoutlines{% + \begingroup + % Thanh's hack / proper braces in bookmarks + \edef\mylbrace{\iftrue \string{\else}\fi}\let\{=\mylbrace + \edef\myrbrace{\iffalse{\else\string}\fi}\let\}=\myrbrace + % + % Read toc silently, to get counts of subentries for \pdfoutline. + \def\numchapentry##1##2##3##4{% + \def\thischapnum{##2}% + \def\thissecnum{0}% + \def\thissubsecnum{0}% + }% + \def\numsecentry##1##2##3##4{% + \advancenumber{chap\thischapnum}% + \def\thissecnum{##2}% + \def\thissubsecnum{0}% + }% + \def\numsubsecentry##1##2##3##4{% + \advancenumber{sec\thissecnum}% + \def\thissubsecnum{##2}% + }% + \def\numsubsubsecentry##1##2##3##4{% + \advancenumber{subsec\thissubsecnum}% + }% + \def\thischapnum{0}% + \def\thissecnum{0}% + \def\thissubsecnum{0}% + % + % use \def rather than \let here because we redefine \chapentry et + % al. a second time, below. + \def\appentry{\numchapentry}% + \def\appsecentry{\numsecentry}% + \def\appsubsecentry{\numsubsecentry}% + \def\appsubsubsecentry{\numsubsubsecentry}% + \def\unnchapentry{\numchapentry}% + \def\unnsecentry{\numsecentry}% + \def\unnsubsecentry{\numsubsecentry}% + \def\unnsubsubsecentry{\numsubsubsecentry}% + \readdatafile{toc}% + % + % Read toc second time, this time actually producing the outlines. + % The `-' means take the \expnumber as the absolute number of + % subentries, which we calculated on our first read of the .toc above. + % + % We use the node names as the destinations. + \def\numchapentry##1##2##3##4{% + \dopdfoutline{##1}{count-\expnumber{chap##2}}{##3}{##4}}% + \def\numsecentry##1##2##3##4{% + \dopdfoutline{##1}{count-\expnumber{sec##2}}{##3}{##4}}% + \def\numsubsecentry##1##2##3##4{% + \dopdfoutline{##1}{count-\expnumber{subsec##2}}{##3}{##4}}% + \def\numsubsubsecentry##1##2##3##4{% count is always zero + \dopdfoutline{##1}{}{##3}{##4}}% + % + % PDF outlines are displayed using system fonts, instead of + % document fonts. Therefore we cannot use special characters, + % since the encoding is unknown. For example, the eogonek from + % Latin 2 (0xea) gets translated to a | character. Info from + % Staszek Wawrykiewicz, 19 Jan 2004 04:09:24 +0100. + % + % xx to do this right, we have to translate 8-bit characters to + % their "best" equivalent, based on the @documentencoding. Right + % now, I guess we'll just let the pdf reader have its way. + \indexnofonts + \setupdatafile + \activebackslash + \input \jobname.toc + \endgroup + } + % + \def\skipspaces#1{\def\PP{#1}\def\D{|}% + \ifx\PP\D\let\nextsp\relax + \else\let\nextsp\skipspaces + \ifx\p\space\else\addtokens{\filename}{\PP}% + \advance\filenamelength by 1 + \fi + \fi + \nextsp} + \def\getfilename#1{\filenamelength=0\expandafter\skipspaces#1|\relax} + \ifnum\pdftexversion < 14 + \let \startlink \pdfannotlink + \else + \let \startlink \pdfstartlink + \fi + \def\pdfurl#1{% + \begingroup + \normalturnoffactive\def\@{@}% + \makevalueexpandable + \leavevmode\Red + \startlink attr{/Border [0 0 0]}% + user{/Subtype /Link /A << /S /URI /URI (#1) >>}% + \endgroup} + \def\pdfgettoks#1.{\setbox\boxA=\hbox{\toksA={#1.}\toksB={}\maketoks}} + \def\addtokens#1#2{\edef\addtoks{\noexpand#1={\the#1#2}}\addtoks} + \def\adn#1{\addtokens{\toksC}{#1}\global\countA=1\let\next=\maketoks} + \def\poptoks#1#2|ENDTOKS|{\let\first=#1\toksD={#1}\toksA={#2}} + \def\maketoks{% + \expandafter\poptoks\the\toksA|ENDTOKS|\relax + \ifx\first0\adn0 + \else\ifx\first1\adn1 \else\ifx\first2\adn2 \else\ifx\first3\adn3 + \else\ifx\first4\adn4 \else\ifx\first5\adn5 \else\ifx\first6\adn6 + \else\ifx\first7\adn7 \else\ifx\first8\adn8 \else\ifx\first9\adn9 + \else + \ifnum0=\countA\else\makelink\fi + \ifx\first.\let\next=\done\else + \let\next=\maketoks + \addtokens{\toksB}{\the\toksD} + \ifx\first,\addtokens{\toksB}{\space}\fi + \fi + \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi + \next} + \def\makelink{\addtokens{\toksB}% + {\noexpand\pdflink{\the\toksC}}\toksC={}\global\countA=0} + \def\pdflink#1{% + \startlink attr{/Border [0 0 0]} goto name{\pdfmkpgn{#1}} + \linkcolor #1\endlink} + \def\done{\edef\st{\global\noexpand\toksA={\the\toksB}}\st} +\else + \let\pdfmkdest = \gobble + \let\pdfurl = \gobble + \let\endlink = \relax + \let\linkcolor = \relax + \let\pdfmakeoutlines = \relax +\fi % \ifx\pdfoutput + + +\message{fonts,} + +% Change the current font style to #1, remembering it in \curfontstyle. +% For now, we do not accumulate font styles: @b{@i{foo}} prints foo in +% italics, not bold italics. +% +\def\setfontstyle#1{% + \def\curfontstyle{#1}% not as a control sequence, because we are \edef'd. + \csname ten#1\endcsname % change the current font +} + +% Select #1 fonts with the current style. +% +\def\selectfonts#1{\csname #1fonts\endcsname \csname\curfontstyle\endcsname} + +\def\rm{\fam=0 \setfontstyle{rm}} +\def\it{\fam=\itfam \setfontstyle{it}} +\def\sl{\fam=\slfam \setfontstyle{sl}} +\def\bf{\fam=\bffam \setfontstyle{bf}}\def\bfstylename{bf} +\def\tt{\fam=\ttfam \setfontstyle{tt}} + +% Texinfo sort of supports the sans serif font style, which plain TeX does not. +% So we set up a \sf. +\newfam\sffam +\def\sf{\fam=\sffam \setfontstyle{sf}} +\let\li = \sf % Sometimes we call it \li, not \sf. + +% We don't need math for this font style. +\def\ttsl{\setfontstyle{ttsl}} + +% Default leading. +\newdimen\textleading \textleading = 13.2pt + +% Set the baselineskip to #1, and the lineskip and strut size +% correspondingly. There is no deep meaning behind these magic numbers +% used as factors; they just match (closely enough) what Knuth defined. +% +\def\lineskipfactor{.08333} +\def\strutheightpercent{.70833} +\def\strutdepthpercent {.29167} +% +\def\setleading#1{% + \normalbaselineskip = #1\relax + \normallineskip = \lineskipfactor\normalbaselineskip + \normalbaselines + \setbox\strutbox =\hbox{% + \vrule width0pt height\strutheightpercent\baselineskip + depth \strutdepthpercent \baselineskip + }% +} + +% Set the font macro #1 to the font named #2, adding on the +% specified font prefix (normally `cm'). +% #3 is the font's design size, #4 is a scale factor +\def\setfont#1#2#3#4{\font#1=\fontprefix#2#3 scaled #4} + +% Use cm as the default font prefix. +% To specify the font prefix, you must define \fontprefix +% before you read in texinfo.tex. +\ifx\fontprefix\undefined +\def\fontprefix{cm} +\fi +% Support font families that don't use the same naming scheme as CM. +\def\rmshape{r} +\def\rmbshape{bx} %where the normal face is bold +\def\bfshape{b} +\def\bxshape{bx} +\def\ttshape{tt} +\def\ttbshape{tt} +\def\ttslshape{sltt} +\def\itshape{ti} +\def\itbshape{bxti} +\def\slshape{sl} +\def\slbshape{bxsl} +\def\sfshape{ss} +\def\sfbshape{ss} +\def\scshape{csc} +\def\scbshape{csc} + +% Text fonts (11.2pt, magstep1). +\def\textnominalsize{11pt} +\edef\mainmagstep{\magstephalf} +\setfont\textrm\rmshape{10}{\mainmagstep} +\setfont\texttt\ttshape{10}{\mainmagstep} +\setfont\textbf\bfshape{10}{\mainmagstep} +\setfont\textit\itshape{10}{\mainmagstep} +\setfont\textsl\slshape{10}{\mainmagstep} +\setfont\textsf\sfshape{10}{\mainmagstep} +\setfont\textsc\scshape{10}{\mainmagstep} +\setfont\textttsl\ttslshape{10}{\mainmagstep} +\font\texti=cmmi10 scaled \mainmagstep +\font\textsy=cmsy10 scaled \mainmagstep + +% A few fonts for @defun names and args. +\setfont\defbf\bfshape{10}{\magstep1} +\setfont\deftt\ttshape{10}{\magstep1} +\setfont\defttsl\ttslshape{10}{\magstep1} +\def\df{\let\tentt=\deftt \let\tenbf = \defbf \let\tenttsl=\defttsl \bf} + +% Fonts for indices, footnotes, small examples (9pt). +\def\smallnominalsize{9pt} +\setfont\smallrm\rmshape{9}{1000} +\setfont\smalltt\ttshape{9}{1000} +\setfont\smallbf\bfshape{10}{900} +\setfont\smallit\itshape{9}{1000} +\setfont\smallsl\slshape{9}{1000} +\setfont\smallsf\sfshape{9}{1000} +\setfont\smallsc\scshape{10}{900} +\setfont\smallttsl\ttslshape{10}{900} +\font\smalli=cmmi9 +\font\smallsy=cmsy9 + +% Fonts for small examples (8pt). +\def\smallernominalsize{8pt} +\setfont\smallerrm\rmshape{8}{1000} +\setfont\smallertt\ttshape{8}{1000} +\setfont\smallerbf\bfshape{10}{800} +\setfont\smallerit\itshape{8}{1000} +\setfont\smallersl\slshape{8}{1000} +\setfont\smallersf\sfshape{8}{1000} +\setfont\smallersc\scshape{10}{800} +\setfont\smallerttsl\ttslshape{10}{800} +\font\smalleri=cmmi8 +\font\smallersy=cmsy8 + +% Fonts for title page (20.4pt): +\def\titlenominalsize{20pt} +\setfont\titlerm\rmbshape{12}{\magstep3} +\setfont\titleit\itbshape{10}{\magstep4} +\setfont\titlesl\slbshape{10}{\magstep4} +\setfont\titlett\ttbshape{12}{\magstep3} +\setfont\titlettsl\ttslshape{10}{\magstep4} +\setfont\titlesf\sfbshape{17}{\magstep1} +\let\titlebf=\titlerm +\setfont\titlesc\scbshape{10}{\magstep4} +\font\titlei=cmmi12 scaled \magstep3 +\font\titlesy=cmsy10 scaled \magstep4 +\def\authorrm{\secrm} +\def\authortt{\sectt} + +% Chapter (and unnumbered) fonts (17.28pt). +\def\chapnominalsize{17pt} +\setfont\chaprm\rmbshape{12}{\magstep2} +\setfont\chapit\itbshape{10}{\magstep3} +\setfont\chapsl\slbshape{10}{\magstep3} +\setfont\chaptt\ttbshape{12}{\magstep2} +\setfont\chapttsl\ttslshape{10}{\magstep3} +\setfont\chapsf\sfbshape{17}{1000} +\let\chapbf=\chaprm +\setfont\chapsc\scbshape{10}{\magstep3} +\font\chapi=cmmi12 scaled \magstep2 +\font\chapsy=cmsy10 scaled \magstep3 + +% Section fonts (14.4pt). +\def\secnominalsize{14pt} +\setfont\secrm\rmbshape{12}{\magstep1} +\setfont\secit\itbshape{10}{\magstep2} +\setfont\secsl\slbshape{10}{\magstep2} +\setfont\sectt\ttbshape{12}{\magstep1} +\setfont\secttsl\ttslshape{10}{\magstep2} +\setfont\secsf\sfbshape{12}{\magstep1} +\let\secbf\secrm +\setfont\secsc\scbshape{10}{\magstep2} +\font\seci=cmmi12 scaled \magstep1 +\font\secsy=cmsy10 scaled \magstep2 + +% Subsection fonts (13.15pt). +\def\ssecnominalsize{13pt} +\setfont\ssecrm\rmbshape{12}{\magstephalf} +\setfont\ssecit\itbshape{10}{1315} +\setfont\ssecsl\slbshape{10}{1315} +\setfont\ssectt\ttbshape{12}{\magstephalf} +\setfont\ssecttsl\ttslshape{10}{1315} +\setfont\ssecsf\sfbshape{12}{\magstephalf} +\let\ssecbf\ssecrm +\setfont\ssecsc\scbshape{10}{1315} +\font\sseci=cmmi12 scaled \magstephalf +\font\ssecsy=cmsy10 scaled 1315 + +% Reduced fonts for @acro in text (10pt). +\def\reducednominalsize{10pt} +\setfont\reducedrm\rmshape{10}{1000} +\setfont\reducedtt\ttshape{10}{1000} +\setfont\reducedbf\bfshape{10}{1000} +\setfont\reducedit\itshape{10}{1000} +\setfont\reducedsl\slshape{10}{1000} +\setfont\reducedsf\sfshape{10}{1000} +\setfont\reducedsc\scshape{10}{1000} +\setfont\reducedttsl\ttslshape{10}{1000} +\font\reducedi=cmmi10 +\font\reducedsy=cmsy10 + +% In order for the font changes to affect most math symbols and letters, +% we have to define the \textfont of the standard families. Since +% texinfo doesn't allow for producing subscripts and superscripts except +% in the main text, we don't bother to reset \scriptfont and +% \scriptscriptfont (which would also require loading a lot more fonts). +% +\def\resetmathfonts{% + \textfont0=\tenrm \textfont1=\teni \textfont2=\tensy + \textfont\itfam=\tenit \textfont\slfam=\tensl \textfont\bffam=\tenbf + \textfont\ttfam=\tentt \textfont\sffam=\tensf +} + +% The font-changing commands redefine the meanings of \tenSTYLE, instead +% of just \STYLE. We do this because \STYLE needs to also set the +% current \fam for math mode. Our \STYLE (e.g., \rm) commands hardwire +% \tenSTYLE to set the current font. +% +% Each font-changing command also sets the names \lsize (one size lower) +% and \lllsize (three sizes lower). These relative commands are used in +% the LaTeX logo and acronyms. +% +% This all needs generalizing, badly. +% +\def\textfonts{% + \let\tenrm=\textrm \let\tenit=\textit \let\tensl=\textsl + \let\tenbf=\textbf \let\tentt=\texttt \let\smallcaps=\textsc + \let\tensf=\textsf \let\teni=\texti \let\tensy=\textsy + \let\tenttsl=\textttsl + \def\curfontsize{text}% + \def\lsize{reduced}\def\lllsize{smaller}% + \resetmathfonts \setleading{\textleading}} +\def\titlefonts{% + \let\tenrm=\titlerm \let\tenit=\titleit \let\tensl=\titlesl + \let\tenbf=\titlebf \let\tentt=\titlett \let\smallcaps=\titlesc + \let\tensf=\titlesf \let\teni=\titlei \let\tensy=\titlesy + \let\tenttsl=\titlettsl + \def\curfontsize{title}% + \def\lsize{chap}\def\lllsize{subsec}% + \resetmathfonts \setleading{25pt}} +\def\titlefont#1{{\titlefonts\rm #1}} +\def\chapfonts{% + \let\tenrm=\chaprm \let\tenit=\chapit \let\tensl=\chapsl + \let\tenbf=\chapbf \let\tentt=\chaptt \let\smallcaps=\chapsc + \let\tensf=\chapsf \let\teni=\chapi \let\tensy=\chapsy + \let\tenttsl=\chapttsl + \def\curfontsize{chap}% + \def\lsize{sec}\def\lllsize{text}% + \resetmathfonts \setleading{19pt}} +\def\secfonts{% + \let\tenrm=\secrm \let\tenit=\secit \let\tensl=\secsl + \let\tenbf=\secbf \let\tentt=\sectt \let\smallcaps=\secsc + \let\tensf=\secsf \let\teni=\seci \let\tensy=\secsy + \let\tenttsl=\secttsl + \def\curfontsize{sec}% + \def\lsize{subsec}\def\lllsize{reduced}% + \resetmathfonts \setleading{16pt}} +\def\subsecfonts{% + \let\tenrm=\ssecrm \let\tenit=\ssecit \let\tensl=\ssecsl + \let\tenbf=\ssecbf \let\tentt=\ssectt \let\smallcaps=\ssecsc + \let\tensf=\ssecsf \let\teni=\sseci \let\tensy=\ssecsy + \let\tenttsl=\ssecttsl + \def\curfontsize{ssec}% + \def\lsize{text}\def\lllsize{small}% + \resetmathfonts \setleading{15pt}} +\let\subsubsecfonts = \subsecfonts +\def\reducedfonts{% + \let\tenrm=\reducedrm \let\tenit=\reducedit \let\tensl=\reducedsl + \let\tenbf=\reducedbf \let\tentt=\reducedtt \let\reducedcaps=\reducedsc + \let\tensf=\reducedsf \let\teni=\reducedi \let\tensy=\reducedsy + \let\tenttsl=\reducedttsl + \def\curfontsize{reduced}% + \def\lsize{small}\def\lllsize{smaller}% + \resetmathfonts \setleading{10.5pt}} +\def\smallfonts{% + \let\tenrm=\smallrm \let\tenit=\smallit \let\tensl=\smallsl + \let\tenbf=\smallbf \let\tentt=\smalltt \let\smallcaps=\smallsc + \let\tensf=\smallsf \let\teni=\smalli \let\tensy=\smallsy + \let\tenttsl=\smallttsl + \def\curfontsize{small}% + \def\lsize{smaller}\def\lllsize{smaller}% + \resetmathfonts \setleading{10.5pt}} +\def\smallerfonts{% + \let\tenrm=\smallerrm \let\tenit=\smallerit \let\tensl=\smallersl + \let\tenbf=\smallerbf \let\tentt=\smallertt \let\smallcaps=\smallersc + \let\tensf=\smallersf \let\teni=\smalleri \let\tensy=\smallersy + \let\tenttsl=\smallerttsl + \def\curfontsize{smaller}% + \def\lsize{smaller}\def\lllsize{smaller}% + \resetmathfonts \setleading{9.5pt}} + +% Set the fonts to use with the @small... environments. +\let\smallexamplefonts = \smallfonts + +% About \smallexamplefonts. If we use \smallfonts (9pt), @smallexample +% can fit this many characters: +% 8.5x11=86 smallbook=72 a4=90 a5=69 +% If we use \scriptfonts (8pt), then we can fit this many characters: +% 8.5x11=90+ smallbook=80 a4=90+ a5=77 +% For me, subjectively, the few extra characters that fit aren't worth +% the additional smallness of 8pt. So I'm making the default 9pt. +% +% By the way, for comparison, here's what fits with @example (10pt): +% 8.5x11=71 smallbook=60 a4=75 a5=58 +% +% I wish the USA used A4 paper. +% --karl, 24jan03. + + +% Set up the default fonts, so we can use them for creating boxes. +% +\textfonts \rm + +% Define these so they can be easily changed for other fonts. +\def\angleleft{$\langle$} +\def\angleright{$\rangle$} + +% Count depth in font-changes, for error checks +\newcount\fontdepth \fontdepth=0 + +% Fonts for short table of contents. +\setfont\shortcontrm\rmshape{12}{1000} +\setfont\shortcontbf\bfshape{10}{\magstep1} % no cmb12 +\setfont\shortcontsl\slshape{12}{1000} +\setfont\shortconttt\ttshape{12}{1000} + +%% Add scribe-like font environments, plus @l for inline lisp (usually sans +%% serif) and @ii for TeX italic + +% \smartitalic{ARG} outputs arg in italics, followed by an italic correction +% unless the following character is such as not to need one. +\def\smartitalicx{\ifx\next,\else\ifx\next-\else\ifx\next.\else + \ptexslash\fi\fi\fi} +\def\smartslanted#1{{\ifusingtt\ttsl\sl #1}\futurelet\next\smartitalicx} +\def\smartitalic#1{{\ifusingtt\ttsl\it #1}\futurelet\next\smartitalicx} + +% like \smartslanted except unconditionally uses \ttsl. +% @var is set to this for defun arguments. +\def\ttslanted#1{{\ttsl #1}\futurelet\next\smartitalicx} + +% like \smartslanted except unconditionally use \sl. We never want +% ttsl for book titles, do we? +\def\cite#1{{\sl #1}\futurelet\next\smartitalicx} + +\let\i=\smartitalic +\let\slanted=\smartslanted +\let\var=\smartslanted +\let\dfn=\smartslanted +\let\emph=\smartitalic + +% @b, explicit bold. +\def\b#1{{\bf #1}} +\let\strong=\b + +% @sansserif, explicit sans. +\def\sansserif#1{{\sf #1}} + +% We can't just use \exhyphenpenalty, because that only has effect at +% the end of a paragraph. Restore normal hyphenation at the end of the +% group within which \nohyphenation is presumably called. +% +\def\nohyphenation{\hyphenchar\font = -1 \aftergroup\restorehyphenation} +\def\restorehyphenation{\hyphenchar\font = `- } + +% Set sfcode to normal for the chars that usually have another value. +% Can't use plain's \frenchspacing because it uses the `\x notation, and +% sometimes \x has an active definition that messes things up. +% +\catcode`@=11 + \def\plainfrenchspacing{% + \sfcode\dotChar =\@m \sfcode\questChar=\@m \sfcode\exclamChar=\@m + \sfcode\colonChar=\@m \sfcode\semiChar =\@m \sfcode\commaChar =\@m + \def\endofsentencespacefactor{1000}% for @. and friends + } + \def\plainnonfrenchspacing{% + \sfcode`\.3000\sfcode`\?3000\sfcode`\!3000 + \sfcode`\:2000\sfcode`\;1500\sfcode`\,1250 + \def\endofsentencespacefactor{3000}% for @. and friends + } +\catcode`@=\other +\def\endofsentencespacefactor{3000}% default + +\def\t#1{% + {\tt \rawbackslash \plainfrenchspacing #1}% + \null +} +\def\samp#1{`\tclose{#1}'\null} +\setfont\keyrm\rmshape{8}{1000} +\font\keysy=cmsy9 +\def\key#1{{\keyrm\textfont2=\keysy \leavevmode\hbox{% + \raise0.4pt\hbox{\angleleft}\kern-.08em\vtop{% + \vbox{\hrule\kern-0.4pt + \hbox{\raise0.4pt\hbox{\vphantom{\angleleft}}#1}}% + \kern-0.4pt\hrule}% + \kern-.06em\raise0.4pt\hbox{\angleright}}}} +% The old definition, with no lozenge: +%\def\key #1{{\ttsl \nohyphenation \uppercase{#1}}\null} +\def\ctrl #1{{\tt \rawbackslash \hat}#1} + +% @file, @option are the same as @samp. +\let\file=\samp +\let\option=\samp + +% @code is a modification of @t, +% which makes spaces the same size as normal in the surrounding text. +\def\tclose#1{% + {% + % Change normal interword space to be same as for the current font. + \spaceskip = \fontdimen2\font + % + % Switch to typewriter. + \tt + % + % But `\ ' produces the large typewriter interword space. + \def\ {{\spaceskip = 0pt{} }}% + % + % Turn off hyphenation. + \nohyphenation + % + \rawbackslash + \plainfrenchspacing + #1% + }% + \null +} + +% We *must* turn on hyphenation at `-' and `_' in @code. +% Otherwise, it is too hard to avoid overfull hboxes +% in the Emacs manual, the Library manual, etc. + +% Unfortunately, TeX uses one parameter (\hyphenchar) to control +% both hyphenation at - and hyphenation within words. +% We must therefore turn them both off (\tclose does that) +% and arrange explicitly to hyphenate at a dash. +% -- rms. +{ + \catcode`\-=\active + \catcode`\_=\active + % + \global\def\code{\begingroup + \catcode`\-=\active \catcode`\_=\active + \ifallowcodebreaks + \let-\codedash + \let_\codeunder + \else + \let-\realdash + \let_\realunder + \fi + \codex + } +} + +\def\realdash{-} +\def\codedash{-\discretionary{}{}{}} +\def\codeunder{% + % this is all so @math{@code{var_name}+1} can work. In math mode, _ + % is "active" (mathcode"8000) and \normalunderscore (or \char95, etc.) + % will therefore expand the active definition of _, which is us + % (inside @code that is), therefore an endless loop. + \ifusingtt{\ifmmode + \mathchar"075F % class 0=ordinary, family 7=ttfam, pos 0x5F=_. + \else\normalunderscore \fi + \discretionary{}{}{}}% + {\_}% +} +\def\codex #1{\tclose{#1}\endgroup} + +% An additional complication: the above will allow breaks after, e.g., +% each of the four underscores in __typeof__. This is undesirable in +% some manuals, especially if they don't have long identifiers in +% general. @allowcodebreaks provides a way to control this. +% +\newif\ifallowcodebreaks \allowcodebreakstrue + +\def\keywordtrue{true} +\def\keywordfalse{false} + +\parseargdef\allowcodebreaks{% + \def\txiarg{#1}% + \ifx\txiarg\keywordtrue + \allowcodebreakstrue + \else\ifx\txiarg\keywordfalse + \allowcodebreaksfalse + \else + \errhelp = \EMsimple + \errmessage{Unknown @allowcodebreaks option `\txiarg'}% + \fi\fi +} + +% @kbd is like @code, except that if the argument is just one @key command, +% then @kbd has no effect. + +% @kbdinputstyle -- arg is `distinct' (@kbd uses slanted tty font always), +% `example' (@kbd uses ttsl only inside of @example and friends), +% or `code' (@kbd uses normal tty font always). +\parseargdef\kbdinputstyle{% + \def\txiarg{#1}% + \ifx\txiarg\worddistinct + \gdef\kbdexamplefont{\ttsl}\gdef\kbdfont{\ttsl}% + \else\ifx\txiarg\wordexample + \gdef\kbdexamplefont{\ttsl}\gdef\kbdfont{\tt}% + \else\ifx\txiarg\wordcode + \gdef\kbdexamplefont{\tt}\gdef\kbdfont{\tt}% + \else + \errhelp = \EMsimple + \errmessage{Unknown @kbdinputstyle option `\txiarg'}% + \fi\fi\fi +} +\def\worddistinct{distinct} +\def\wordexample{example} +\def\wordcode{code} + +% Default is `distinct.' +\kbdinputstyle distinct + +\def\xkey{\key} +\def\kbdfoo#1#2#3\par{\def\one{#1}\def\three{#3}\def\threex{??}% +\ifx\one\xkey\ifx\threex\three \key{#2}% +\else{\tclose{\kbdfont\look}}\fi +\else{\tclose{\kbdfont\look}}\fi} + +% For @indicateurl, @env, @command quotes seem unnecessary, so use \code. +\let\indicateurl=\code +\let\env=\code +\let\command=\code + +% @uref (abbreviation for `urlref') takes an optional (comma-separated) +% second argument specifying the text to display and an optional third +% arg as text to display instead of (rather than in addition to) the url +% itself. First (mandatory) arg is the url. Perhaps eventually put in +% a hypertex \special here. +% +\def\uref#1{\douref #1,,,\finish} +\def\douref#1,#2,#3,#4\finish{\begingroup + \unsepspaces + \pdfurl{#1}% + \setbox0 = \hbox{\ignorespaces #3}% + \ifdim\wd0 > 0pt + \unhbox0 % third arg given, show only that + \else + \setbox0 = \hbox{\ignorespaces #2}% + \ifdim\wd0 > 0pt + \ifpdf + \unhbox0 % PDF: 2nd arg given, show only it + \else + \unhbox0\ (\code{#1})% DVI: 2nd arg given, show both it and url + \fi + \else + \code{#1}% only url given, so show it + \fi + \fi + \endlink +\endgroup} + +% @url synonym for @uref, since that's how everyone uses it. +% +\let\url=\uref + +% rms does not like angle brackets --karl, 17may97. +% So now @email is just like @uref, unless we are pdf. +% +%\def\email#1{\angleleft{\tt #1}\angleright} +\ifpdf + \def\email#1{\doemail#1,,\finish} + \def\doemail#1,#2,#3\finish{\begingroup + \unsepspaces + \pdfurl{mailto:#1}% + \setbox0 = \hbox{\ignorespaces #2}% + \ifdim\wd0>0pt\unhbox0\else\code{#1}\fi + \endlink + \endgroup} +\else + \let\email=\uref +\fi + +% Check if we are currently using a typewriter font. Since all the +% Computer Modern typewriter fonts have zero interword stretch (and +% shrink), and it is reasonable to expect all typewriter fonts to have +% this property, we can check that font parameter. +% +\def\ifmonospace{\ifdim\fontdimen3\font=0pt } + +% Typeset a dimension, e.g., `in' or `pt'. The only reason for the +% argument is to make the input look right: @dmn{pt} instead of @dmn{}pt. +% +\def\dmn#1{\thinspace #1} + +\def\kbd#1{\def\look{#1}\expandafter\kbdfoo\look??\par} + +% @l was never documented to mean ``switch to the Lisp font'', +% and it is not used as such in any manual I can find. We need it for +% Polish suppressed-l. --karl, 22sep96. +%\def\l#1{{\li #1}\null} + +% Explicit font changes: @r, @sc, undocumented @ii. +\def\r#1{{\rm #1}} % roman font +\def\sc#1{{\smallcaps#1}} % smallcaps font +\def\ii#1{{\it #1}} % italic font + +% @acronym for "FBI", "NATO", and the like. +% We print this one point size smaller, since it's intended for +% all-uppercase. +% +\def\acronym#1{\doacronym #1,,\finish} +\def\doacronym#1,#2,#3\finish{% + {\selectfonts\lsize #1}% + \def\temp{#2}% + \ifx\temp\empty \else + \space ({\unsepspaces \ignorespaces \temp \unskip})% + \fi +} + +% @abbr for "Comput. J." and the like. +% No font change, but don't do end-of-sentence spacing. +% +\def\abbr#1{\doabbr #1,,\finish} +\def\doabbr#1,#2,#3\finish{% + {\plainfrenchspacing #1}% + \def\temp{#2}% + \ifx\temp\empty \else + \space ({\unsepspaces \ignorespaces \temp \unskip})% + \fi +} + +% @pounds{} is a sterling sign, which Knuth put in the CM italic font. +% +\def\pounds{{\it\$}} + +% @euro{} comes from a separate font, depending on the current style. +% We use the free feym* fonts from the eurosym package by Henrik +% Theiling, which support regular, slanted, bold and bold slanted (and +% "outlined" (blackboard board, sort of) versions, which we don't need). +% It is available from http://www.ctan.org/tex-archive/fonts/eurosym. +% +% Although only regular is the truly official Euro symbol, we ignore +% that. The Euro is designed to be slightly taller than the regular +% font height. +% +% feymr - regular +% feymo - slanted +% feybr - bold +% feybo - bold slanted +% +% There is no good (free) typewriter version, to my knowledge. +% A feymr10 euro is ~7.3pt wide, while a normal cmtt10 char is ~5.25pt wide. +% Hmm. +% +% Also doesn't work in math. Do we need to do math with euro symbols? +% Hope not. +% +% +\def\euro{{\eurofont e}} +\def\eurofont{% + % We set the font at each command, rather than predefining it in + % \textfonts and the other font-switching commands, so that + % installations which never need the symbol don't have to have the + % font installed. + % + % There is only one designed size (nominal 10pt), so we always scale + % that to the current nominal size. + % + % By the way, simply using "at 1em" works for cmr10 and the like, but + % does not work for cmbx10 and other extended/shrunken fonts. + % + \def\eurosize{\csname\curfontsize nominalsize\endcsname}% + % + \ifx\curfontstyle\bfstylename + % bold: + \font\thiseurofont = \ifusingit{feybo10}{feybr10} at \eurosize + \else + % regular: + \font\thiseurofont = \ifusingit{feymo10}{feymr10} at \eurosize + \fi + \thiseurofont +} + +% @registeredsymbol - R in a circle. The font for the R should really +% be smaller yet, but lllsize is the best we can do for now. +% Adapted from the plain.tex definition of \copyright. +% +\def\registeredsymbol{% + $^{{\ooalign{\hfil\raise.07ex\hbox{\selectfonts\lllsize R}% + \hfil\crcr\Orb}}% + }$% +} + +% Laurent Siebenmann reports \Orb undefined with: +% Textures 1.7.7 (preloaded format=plain 93.10.14) (68K) 16 APR 2004 02:38 +% so we'll define it if necessary. +% +\ifx\Orb\undefined +\def\Orb{\mathhexbox20D} +\fi + + +\message{page headings,} + +\newskip\titlepagetopglue \titlepagetopglue = 1.5in +\newskip\titlepagebottomglue \titlepagebottomglue = 2pc + +% First the title page. Must do @settitle before @titlepage. +\newif\ifseenauthor +\newif\iffinishedtitlepage + +% Do an implicit @contents or @shortcontents after @end titlepage if the +% user says @setcontentsaftertitlepage or @setshortcontentsaftertitlepage. +% +\newif\ifsetcontentsaftertitlepage + \let\setcontentsaftertitlepage = \setcontentsaftertitlepagetrue +\newif\ifsetshortcontentsaftertitlepage + \let\setshortcontentsaftertitlepage = \setshortcontentsaftertitlepagetrue + +\parseargdef\shorttitlepage{\begingroup\hbox{}\vskip 1.5in \chaprm \centerline{#1}% + \endgroup\page\hbox{}\page} + +\envdef\titlepage{% + % Open one extra group, as we want to close it in the middle of \Etitlepage. + \begingroup + \parindent=0pt \textfonts + % Leave some space at the very top of the page. + \vglue\titlepagetopglue + % No rule at page bottom unless we print one at the top with @title. + \finishedtitlepagetrue + % + % Most title ``pages'' are actually two pages long, with space + % at the top of the second. We don't want the ragged left on the second. + \let\oldpage = \page + \def\page{% + \iffinishedtitlepage\else + \finishtitlepage + \fi + \let\page = \oldpage + \page + \null + }% +} + +\def\Etitlepage{% + \iffinishedtitlepage\else + \finishtitlepage + \fi + % It is important to do the page break before ending the group, + % because the headline and footline are only empty inside the group. + % If we use the new definition of \page, we always get a blank page + % after the title page, which we certainly don't want. + \oldpage + \endgroup + % + % Need this before the \...aftertitlepage checks so that if they are + % in effect the toc pages will come out with page numbers. + \HEADINGSon + % + % If they want short, they certainly want long too. + \ifsetshortcontentsaftertitlepage + \shortcontents + \contents + \global\let\shortcontents = \relax + \global\let\contents = \relax + \fi + % + \ifsetcontentsaftertitlepage + \contents + \global\let\contents = \relax + \global\let\shortcontents = \relax + \fi +} + +\def\finishtitlepage{% + \vskip4pt \hrule height 2pt width \hsize + \vskip\titlepagebottomglue + \finishedtitlepagetrue +} + +%%% Macros to be used within @titlepage: + +\let\subtitlerm=\tenrm +\def\subtitlefont{\subtitlerm \normalbaselineskip = 13pt \normalbaselines} + +\def\authorfont{\authorrm \normalbaselineskip = 16pt \normalbaselines + \let\tt=\authortt} + +\parseargdef\title{% + \checkenv\titlepage + \leftline{\titlefonts\rm #1} + % print a rule at the page bottom also. + \finishedtitlepagefalse + \vskip4pt \hrule height 4pt width \hsize \vskip4pt +} + +\parseargdef\subtitle{% + \checkenv\titlepage + {\subtitlefont \rightline{#1}}% +} + +% @author should come last, but may come many times. +% It can also be used inside @quotation. +% +\parseargdef\author{% + \def\temp{\quotation}% + \ifx\thisenv\temp + \def\quotationauthor{#1}% printed in \Equotation. + \else + \checkenv\titlepage + \ifseenauthor\else \vskip 0pt plus 1filll \seenauthortrue \fi + {\authorfont \leftline{#1}}% + \fi +} + + +%%% Set up page headings and footings. + +\let\thispage=\folio + +\newtoks\evenheadline % headline on even pages +\newtoks\oddheadline % headline on odd pages +\newtoks\evenfootline % footline on even pages +\newtoks\oddfootline % footline on odd pages + +% Now make TeX use those variables +\headline={{\textfonts\rm \ifodd\pageno \the\oddheadline + \else \the\evenheadline \fi}} +\footline={{\textfonts\rm \ifodd\pageno \the\oddfootline + \else \the\evenfootline \fi}\HEADINGShook} +\let\HEADINGShook=\relax + +% Commands to set those variables. +% For example, this is what @headings on does +% @evenheading @thistitle|@thispage|@thischapter +% @oddheading @thischapter|@thispage|@thistitle +% @evenfooting @thisfile|| +% @oddfooting ||@thisfile + + +\def\evenheading{\parsearg\evenheadingxxx} +\def\evenheadingxxx #1{\evenheadingyyy #1\|\|\|\|\finish} +\def\evenheadingyyy #1\|#2\|#3\|#4\finish{% +\global\evenheadline={\rlap{\centerline{#2}}\line{#1\hfil#3}}} + +\def\oddheading{\parsearg\oddheadingxxx} +\def\oddheadingxxx #1{\oddheadingyyy #1\|\|\|\|\finish} +\def\oddheadingyyy #1\|#2\|#3\|#4\finish{% +\global\oddheadline={\rlap{\centerline{#2}}\line{#1\hfil#3}}} + +\parseargdef\everyheading{\oddheadingxxx{#1}\evenheadingxxx{#1}}% + +\def\evenfooting{\parsearg\evenfootingxxx} +\def\evenfootingxxx #1{\evenfootingyyy #1\|\|\|\|\finish} +\def\evenfootingyyy #1\|#2\|#3\|#4\finish{% +\global\evenfootline={\rlap{\centerline{#2}}\line{#1\hfil#3}}} + +\def\oddfooting{\parsearg\oddfootingxxx} +\def\oddfootingxxx #1{\oddfootingyyy #1\|\|\|\|\finish} +\def\oddfootingyyy #1\|#2\|#3\|#4\finish{% + \global\oddfootline = {\rlap{\centerline{#2}}\line{#1\hfil#3}}% + % + % Leave some space for the footline. Hopefully ok to assume + % @evenfooting will not be used by itself. + \global\advance\pageheight by -\baselineskip + \global\advance\vsize by -\baselineskip +} + +\parseargdef\everyfooting{\oddfootingxxx{#1}\evenfootingxxx{#1}} + + +% @headings double turns headings on for double-sided printing. +% @headings single turns headings on for single-sided printing. +% @headings off turns them off. +% @headings on same as @headings double, retained for compatibility. +% @headings after turns on double-sided headings after this page. +% @headings doubleafter turns on double-sided headings after this page. +% @headings singleafter turns on single-sided headings after this page. +% By default, they are off at the start of a document, +% and turned `on' after @end titlepage. + +\def\headings #1 {\csname HEADINGS#1\endcsname} + +\def\HEADINGSoff{% +\global\evenheadline={\hfil} \global\evenfootline={\hfil} +\global\oddheadline={\hfil} \global\oddfootline={\hfil}} +\HEADINGSoff +% When we turn headings on, set the page number to 1. +% For double-sided printing, put current file name in lower left corner, +% chapter name on inside top of right hand pages, document +% title on inside top of left hand pages, and page numbers on outside top +% edge of all pages. +\def\HEADINGSdouble{% +\global\pageno=1 +\global\evenfootline={\hfil} +\global\oddfootline={\hfil} +\global\evenheadline={\line{\folio\hfil\thistitle}} +\global\oddheadline={\line{\thischapter\hfil\folio}} +\global\let\contentsalignmacro = \chapoddpage +} +\let\contentsalignmacro = \chappager + +% For single-sided printing, chapter title goes across top left of page, +% page number on top right. +\def\HEADINGSsingle{% +\global\pageno=1 +\global\evenfootline={\hfil} +\global\oddfootline={\hfil} +\global\evenheadline={\line{\thischapter\hfil\folio}} +\global\oddheadline={\line{\thischapter\hfil\folio}} +\global\let\contentsalignmacro = \chappager +} +\def\HEADINGSon{\HEADINGSdouble} + +\def\HEADINGSafter{\let\HEADINGShook=\HEADINGSdoublex} +\let\HEADINGSdoubleafter=\HEADINGSafter +\def\HEADINGSdoublex{% +\global\evenfootline={\hfil} +\global\oddfootline={\hfil} +\global\evenheadline={\line{\folio\hfil\thistitle}} +\global\oddheadline={\line{\thischapter\hfil\folio}} +\global\let\contentsalignmacro = \chapoddpage +} + +\def\HEADINGSsingleafter{\let\HEADINGShook=\HEADINGSsinglex} +\def\HEADINGSsinglex{% +\global\evenfootline={\hfil} +\global\oddfootline={\hfil} +\global\evenheadline={\line{\thischapter\hfil\folio}} +\global\oddheadline={\line{\thischapter\hfil\folio}} +\global\let\contentsalignmacro = \chappager +} + +% Subroutines used in generating headings +% This produces Day Month Year style of output. +% Only define if not already defined, in case a txi-??.tex file has set +% up a different format (e.g., txi-cs.tex does this). +\ifx\today\undefined +\def\today{% + \number\day\space + \ifcase\month + \or\putwordMJan\or\putwordMFeb\or\putwordMMar\or\putwordMApr + \or\putwordMMay\or\putwordMJun\or\putwordMJul\or\putwordMAug + \or\putwordMSep\or\putwordMOct\or\putwordMNov\or\putwordMDec + \fi + \space\number\year} +\fi + +% @settitle line... specifies the title of the document, for headings. +% It generates no output of its own. +\def\thistitle{\putwordNoTitle} +\def\settitle{\parsearg{\gdef\thistitle}} + + +\message{tables,} +% Tables -- @table, @ftable, @vtable, @item(x). + +% default indentation of table text +\newdimen\tableindent \tableindent=.8in +% default indentation of @itemize and @enumerate text +\newdimen\itemindent \itemindent=.3in +% margin between end of table item and start of table text. +\newdimen\itemmargin \itemmargin=.1in + +% used internally for \itemindent minus \itemmargin +\newdimen\itemmax + +% Note @table, @ftable, and @vtable define @item, @itemx, etc., with +% these defs. +% They also define \itemindex +% to index the item name in whatever manner is desired (perhaps none). + +\newif\ifitemxneedsnegativevskip + +\def\itemxpar{\par\ifitemxneedsnegativevskip\nobreak\vskip-\parskip\nobreak\fi} + +\def\internalBitem{\smallbreak \parsearg\itemzzz} +\def\internalBitemx{\itemxpar \parsearg\itemzzz} + +\def\itemzzz #1{\begingroup % + \advance\hsize by -\rightskip + \advance\hsize by -\tableindent + \setbox0=\hbox{\itemindicate{#1}}% + \itemindex{#1}% + \nobreak % This prevents a break before @itemx. + % + % If the item text does not fit in the space we have, put it on a line + % by itself, and do not allow a page break either before or after that + % line. We do not start a paragraph here because then if the next + % command is, e.g., @kindex, the whatsit would get put into the + % horizontal list on a line by itself, resulting in extra blank space. + \ifdim \wd0>\itemmax + % + % Make this a paragraph so we get the \parskip glue and wrapping, + % but leave it ragged-right. + \begingroup + \advance\leftskip by-\tableindent + \advance\hsize by\tableindent + \advance\rightskip by0pt plus1fil + \leavevmode\unhbox0\par + \endgroup + % + % We're going to be starting a paragraph, but we don't want the + % \parskip glue -- logically it's part of the @item we just started. + \nobreak \vskip-\parskip + % + % Stop a page break at the \parskip glue coming up. However, if + % what follows is an environment such as @example, there will be no + % \parskip glue; then the negative vskip we just inserted would + % cause the example and the item to crash together. So we use this + % bizarre value of 10001 as a signal to \aboveenvbreak to insert + % \parskip glue after all. Section titles are handled this way also. + % + \penalty 10001 + \endgroup + \itemxneedsnegativevskipfalse + \else + % The item text fits into the space. Start a paragraph, so that the + % following text (if any) will end up on the same line. + \noindent + % Do this with kerns and \unhbox so that if there is a footnote in + % the item text, it can migrate to the main vertical list and + % eventually be printed. + \nobreak\kern-\tableindent + \dimen0 = \itemmax \advance\dimen0 by \itemmargin \advance\dimen0 by -\wd0 + \unhbox0 + \nobreak\kern\dimen0 + \endgroup + \itemxneedsnegativevskiptrue + \fi +} + +\def\item{\errmessage{@item while not in a list environment}} +\def\itemx{\errmessage{@itemx while not in a list environment}} + +% @table, @ftable, @vtable. +\envdef\table{% + \let\itemindex\gobble + \tablecheck{table}% +} +\envdef\ftable{% + \def\itemindex ##1{\doind {fn}{\code{##1}}}% + \tablecheck{ftable}% +} +\envdef\vtable{% + \def\itemindex ##1{\doind {vr}{\code{##1}}}% + \tablecheck{vtable}% +} +\def\tablecheck#1{% + \ifnum \the\catcode`\^^M=\active + \endgroup + \errmessage{This command won't work in this context; perhaps the problem is + that we are \inenvironment\thisenv}% + \def\next{\doignore{#1}}% + \else + \let\next\tablex + \fi + \next +} +\def\tablex#1{% + \def\itemindicate{#1}% + \parsearg\tabley +} +\def\tabley#1{% + {% + \makevalueexpandable + \edef\temp{\noexpand\tablez #1\space\space\space}% + \expandafter + }\temp \endtablez +} +\def\tablez #1 #2 #3 #4\endtablez{% + \aboveenvbreak + \ifnum 0#1>0 \advance \leftskip by #1\mil \fi + \ifnum 0#2>0 \tableindent=#2\mil \fi + \ifnum 0#3>0 \advance \rightskip by #3\mil \fi + \itemmax=\tableindent + \advance \itemmax by -\itemmargin + \advance \leftskip by \tableindent + \exdentamount=\tableindent + \parindent = 0pt + \parskip = \smallskipamount + \ifdim \parskip=0pt \parskip=2pt \fi + \let\item = \internalBitem + \let\itemx = \internalBitemx +} +\def\Etable{\endgraf\afterenvbreak} +\let\Eftable\Etable +\let\Evtable\Etable +\let\Eitemize\Etable +\let\Eenumerate\Etable + +% This is the counter used by @enumerate, which is really @itemize + +\newcount \itemno + +\envdef\itemize{\parsearg\doitemize} + +\def\doitemize#1{% + \aboveenvbreak + \itemmax=\itemindent + \advance\itemmax by -\itemmargin + \advance\leftskip by \itemindent + \exdentamount=\itemindent + \parindent=0pt + \parskip=\smallskipamount + \ifdim\parskip=0pt \parskip=2pt \fi + \def\itemcontents{#1}% + % @itemize with no arg is equivalent to @itemize @bullet. + \ifx\itemcontents\empty\def\itemcontents{\bullet}\fi + \let\item=\itemizeitem +} + +% Definition of @item while inside @itemize and @enumerate. +% +\def\itemizeitem{% + \advance\itemno by 1 % for enumerations + {\let\par=\endgraf \smallbreak}% reasonable place to break + {% + % If the document has an @itemize directly after a section title, a + % \nobreak will be last on the list, and \sectionheading will have + % done a \vskip-\parskip. In that case, we don't want to zero + % parskip, or the item text will crash with the heading. On the + % other hand, when there is normal text preceding the item (as there + % usually is), we do want to zero parskip, or there would be too much + % space. In that case, we won't have a \nobreak before. At least + % that's the theory. + \ifnum\lastpenalty<10000 \parskip=0in \fi + \noindent + \hbox to 0pt{\hss \itemcontents \kern\itemmargin}% + \vadjust{\penalty 1200}}% not good to break after first line of item. + \flushcr +} + +% \splitoff TOKENS\endmark defines \first to be the first token in +% TOKENS, and \rest to be the remainder. +% +\def\splitoff#1#2\endmark{\def\first{#1}\def\rest{#2}}% + +% Allow an optional argument of an uppercase letter, lowercase letter, +% or number, to specify the first label in the enumerated list. No +% argument is the same as `1'. +% +\envparseargdef\enumerate{\enumeratey #1 \endenumeratey} +\def\enumeratey #1 #2\endenumeratey{% + % If we were given no argument, pretend we were given `1'. + \def\thearg{#1}% + \ifx\thearg\empty \def\thearg{1}\fi + % + % Detect if the argument is a single token. If so, it might be a + % letter. Otherwise, the only valid thing it can be is a number. + % (We will always have one token, because of the test we just made. + % This is a good thing, since \splitoff doesn't work given nothing at + % all -- the first parameter is undelimited.) + \expandafter\splitoff\thearg\endmark + \ifx\rest\empty + % Only one token in the argument. It could still be anything. + % A ``lowercase letter'' is one whose \lccode is nonzero. + % An ``uppercase letter'' is one whose \lccode is both nonzero, and + % not equal to itself. + % Otherwise, we assume it's a number. + % + % We need the \relax at the end of the \ifnum lines to stop TeX from + % continuing to look for a <number>. + % + \ifnum\lccode\expandafter`\thearg=0\relax + \numericenumerate % a number (we hope) + \else + % It's a letter. + \ifnum\lccode\expandafter`\thearg=\expandafter`\thearg\relax + \lowercaseenumerate % lowercase letter + \else + \uppercaseenumerate % uppercase letter + \fi + \fi + \else + % Multiple tokens in the argument. We hope it's a number. + \numericenumerate + \fi +} + +% An @enumerate whose labels are integers. The starting integer is +% given in \thearg. +% +\def\numericenumerate{% + \itemno = \thearg + \startenumeration{\the\itemno}% +} + +% The starting (lowercase) letter is in \thearg. +\def\lowercaseenumerate{% + \itemno = \expandafter`\thearg + \startenumeration{% + % Be sure we're not beyond the end of the alphabet. + \ifnum\itemno=0 + \errmessage{No more lowercase letters in @enumerate; get a bigger + alphabet}% + \fi + \char\lccode\itemno + }% +} + +% The starting (uppercase) letter is in \thearg. +\def\uppercaseenumerate{% + \itemno = \expandafter`\thearg + \startenumeration{% + % Be sure we're not beyond the end of the alphabet. + \ifnum\itemno=0 + \errmessage{No more uppercase letters in @enumerate; get a bigger + alphabet} + \fi + \char\uccode\itemno + }% +} + +% Call \doitemize, adding a period to the first argument and supplying the +% common last two arguments. Also subtract one from the initial value in +% \itemno, since @item increments \itemno. +% +\def\startenumeration#1{% + \advance\itemno by -1 + \doitemize{#1.}\flushcr +} + +% @alphaenumerate and @capsenumerate are abbreviations for giving an arg +% to @enumerate. +% +\def\alphaenumerate{\enumerate{a}} +\def\capsenumerate{\enumerate{A}} +\def\Ealphaenumerate{\Eenumerate} +\def\Ecapsenumerate{\Eenumerate} + + +% @multitable macros +% Amy Hendrickson, 8/18/94, 3/6/96 +% +% @multitable ... @end multitable will make as many columns as desired. +% Contents of each column will wrap at width given in preamble. Width +% can be specified either with sample text given in a template line, +% or in percent of \hsize, the current width of text on page. + +% Table can continue over pages but will only break between lines. + +% To make preamble: +% +% Either define widths of columns in terms of percent of \hsize: +% @multitable @columnfractions .25 .3 .45 +% @item ... +% +% Numbers following @columnfractions are the percent of the total +% current hsize to be used for each column. You may use as many +% columns as desired. + + +% Or use a template: +% @multitable {Column 1 template} {Column 2 template} {Column 3 template} +% @item ... +% using the widest term desired in each column. + +% Each new table line starts with @item, each subsequent new column +% starts with @tab. Empty columns may be produced by supplying @tab's +% with nothing between them for as many times as empty columns are needed, +% ie, @tab@tab@tab will produce two empty columns. + +% @item, @tab do not need to be on their own lines, but it will not hurt +% if they are. + +% Sample multitable: + +% @multitable {Column 1 template} {Column 2 template} {Column 3 template} +% @item first col stuff @tab second col stuff @tab third col +% @item +% first col stuff +% @tab +% second col stuff +% @tab +% third col +% @item first col stuff @tab second col stuff +% @tab Many paragraphs of text may be used in any column. +% +% They will wrap at the width determined by the template. +% @item@tab@tab This will be in third column. +% @end multitable + +% Default dimensions may be reset by user. +% @multitableparskip is vertical space between paragraphs in table. +% @multitableparindent is paragraph indent in table. +% @multitablecolmargin is horizontal space to be left between columns. +% @multitablelinespace is space to leave between table items, baseline +% to baseline. +% 0pt means it depends on current normal line spacing. +% +\newskip\multitableparskip +\newskip\multitableparindent +\newdimen\multitablecolspace +\newskip\multitablelinespace +\multitableparskip=0pt +\multitableparindent=6pt +\multitablecolspace=12pt +\multitablelinespace=0pt + +% Macros used to set up halign preamble: +% +\let\endsetuptable\relax +\def\xendsetuptable{\endsetuptable} +\let\columnfractions\relax +\def\xcolumnfractions{\columnfractions} +\newif\ifsetpercent + +% #1 is the @columnfraction, usually a decimal number like .5, but might +% be just 1. We just use it, whatever it is. +% +\def\pickupwholefraction#1 {% + \global\advance\colcount by 1 + \expandafter\xdef\csname col\the\colcount\endcsname{#1\hsize}% + \setuptable +} + +\newcount\colcount +\def\setuptable#1{% + \def\firstarg{#1}% + \ifx\firstarg\xendsetuptable + \let\go = \relax + \else + \ifx\firstarg\xcolumnfractions + \global\setpercenttrue + \else + \ifsetpercent + \let\go\pickupwholefraction + \else + \global\advance\colcount by 1 + \setbox0=\hbox{#1\unskip\space}% Add a normal word space as a + % separator; typically that is always in the input, anyway. + \expandafter\xdef\csname col\the\colcount\endcsname{\the\wd0}% + \fi + \fi + \ifx\go\pickupwholefraction + % Put the argument back for the \pickupwholefraction call, so + % we'll always have a period there to be parsed. + \def\go{\pickupwholefraction#1}% + \else + \let\go = \setuptable + \fi% + \fi + \go +} + +% multitable-only commands. +% +% @headitem starts a heading row, which we typeset in bold. +% Assignments have to be global since we are inside the implicit group +% of an alignment entry. Note that \everycr resets \everytab. +\def\headitem{\checkenv\multitable \crcr \global\everytab={\bf}\the\everytab}% +% +% A \tab used to include \hskip1sp. But then the space in a template +% line is not enough. That is bad. So let's go back to just `&' until +% we encounter the problem it was intended to solve again. +% --karl, nathan@acm.org, 20apr99. +\def\tab{\checkenv\multitable &\the\everytab}% + +% @multitable ... @end multitable definitions: +% +\newtoks\everytab % insert after every tab. +% +\envdef\multitable{% + \vskip\parskip + \startsavinginserts + % + % @item within a multitable starts a normal row. + % We use \def instead of \let so that if one of the multitable entries + % contains an @itemize, we don't choke on the \item (seen as \crcr aka + % \endtemplate) expanding \doitemize. + \def\item{\crcr}% + % + \tolerance=9500 + \hbadness=9500 + \setmultitablespacing + \parskip=\multitableparskip + \parindent=\multitableparindent + \overfullrule=0pt + \global\colcount=0 + % + \everycr = {% + \noalign{% + \global\everytab={}% + \global\colcount=0 % Reset the column counter. + % Check for saved footnotes, etc. + \checkinserts + % Keeps underfull box messages off when table breaks over pages. + %\filbreak + % Maybe so, but it also creates really weird page breaks when the + % table breaks over pages. Wouldn't \vfil be better? Wait until the + % problem manifests itself, so it can be fixed for real --karl. + }% + }% + % + \parsearg\domultitable +} +\def\domultitable#1{% + % To parse everything between @multitable and @item: + \setuptable#1 \endsetuptable + % + % This preamble sets up a generic column definition, which will + % be used as many times as user calls for columns. + % \vtop will set a single line and will also let text wrap and + % continue for many paragraphs if desired. + \halign\bgroup &% + \global\advance\colcount by 1 + \multistrut + \vtop{% + % Use the current \colcount to find the correct column width: + \hsize=\expandafter\csname col\the\colcount\endcsname + % + % In order to keep entries from bumping into each other + % we will add a \leftskip of \multitablecolspace to all columns after + % the first one. + % + % If a template has been used, we will add \multitablecolspace + % to the width of each template entry. + % + % If the user has set preamble in terms of percent of \hsize we will + % use that dimension as the width of the column, and the \leftskip + % will keep entries from bumping into each other. Table will start at + % left margin and final column will justify at right margin. + % + % Make sure we don't inherit \rightskip from the outer environment. + \rightskip=0pt + \ifnum\colcount=1 + % The first column will be indented with the surrounding text. + \advance\hsize by\leftskip + \else + \ifsetpercent \else + % If user has not set preamble in terms of percent of \hsize + % we will advance \hsize by \multitablecolspace. + \advance\hsize by \multitablecolspace + \fi + % In either case we will make \leftskip=\multitablecolspace: + \leftskip=\multitablecolspace + \fi + % Ignoring space at the beginning and end avoids an occasional spurious + % blank line, when TeX decides to break the line at the space before the + % box from the multistrut, so the strut ends up on a line by itself. + % For example: + % @multitable @columnfractions .11 .89 + % @item @code{#} + % @tab Legal holiday which is valid in major parts of the whole country. + % Is automatically provided with highlighting sequences respectively + % marking characters. + \noindent\ignorespaces##\unskip\multistrut + }\cr +} +\def\Emultitable{% + \crcr + \egroup % end the \halign + \global\setpercentfalse +} + +\def\setmultitablespacing{% + \def\multistrut{\strut}% just use the standard line spacing + % + % Compute \multitablelinespace (if not defined by user) for use in + % \multitableparskip calculation. We used define \multistrut based on + % this, but (ironically) that caused the spacing to be off. + % See bug-texinfo report from Werner Lemberg, 31 Oct 2004 12:52:20 +0100. +\ifdim\multitablelinespace=0pt +\setbox0=\vbox{X}\global\multitablelinespace=\the\baselineskip +\global\advance\multitablelinespace by-\ht0 +\fi +%% Test to see if parskip is larger than space between lines of +%% table. If not, do nothing. +%% If so, set to same dimension as multitablelinespace. +\ifdim\multitableparskip>\multitablelinespace +\global\multitableparskip=\multitablelinespace +\global\advance\multitableparskip-7pt %% to keep parskip somewhat smaller + %% than skip between lines in the table. +\fi% +\ifdim\multitableparskip=0pt +\global\multitableparskip=\multitablelinespace +\global\advance\multitableparskip-7pt %% to keep parskip somewhat smaller + %% than skip between lines in the table. +\fi} + + +\message{conditionals,} + +% @iftex, @ifnotdocbook, @ifnothtml, @ifnotinfo, @ifnotplaintext, +% @ifnotxml always succeed. They currently do nothing; we don't +% attempt to check whether the conditionals are properly nested. But we +% have to remember that they are conditionals, so that @end doesn't +% attempt to close an environment group. +% +\def\makecond#1{% + \expandafter\let\csname #1\endcsname = \relax + \expandafter\let\csname iscond.#1\endcsname = 1 +} +\makecond{iftex} +\makecond{ifnotdocbook} +\makecond{ifnothtml} +\makecond{ifnotinfo} +\makecond{ifnotplaintext} +\makecond{ifnotxml} + +% Ignore @ignore, @ifhtml, @ifinfo, and the like. +% +\def\direntry{\doignore{direntry}} +\def\documentdescription{\doignore{documentdescription}} +\def\docbook{\doignore{docbook}} +\def\html{\doignore{html}} +\def\ifdocbook{\doignore{ifdocbook}} +\def\ifhtml{\doignore{ifhtml}} +\def\ifinfo{\doignore{ifinfo}} +\def\ifnottex{\doignore{ifnottex}} +\def\ifplaintext{\doignore{ifplaintext}} +\def\ifxml{\doignore{ifxml}} +\def\ignore{\doignore{ignore}} +\def\menu{\doignore{menu}} +\def\xml{\doignore{xml}} + +% Ignore text until a line `@end #1', keeping track of nested conditionals. +% +% A count to remember the depth of nesting. +\newcount\doignorecount + +\def\doignore#1{\begingroup + % Scan in ``verbatim'' mode: + \catcode`\@ = \other + \catcode`\{ = \other + \catcode`\} = \other + % + % Make sure that spaces turn into tokens that match what \doignoretext wants. + \spaceisspace + % + % Count number of #1's that we've seen. + \doignorecount = 0 + % + % Swallow text until we reach the matching `@end #1'. + \dodoignore{#1}% +} + +{ \catcode`_=11 % We want to use \_STOP_ which cannot appear in texinfo source. + \obeylines % + % + \gdef\dodoignore#1{% + % #1 contains the command name as a string, e.g., `ifinfo'. + % + % Define a command to find the next `@end #1', which must be on a line + % by itself. + \long\def\doignoretext##1^^M@end #1{\doignoretextyyy##1^^M@#1\_STOP_}% + % And this command to find another #1 command, at the beginning of a + % line. (Otherwise, we would consider a line `@c @ifset', for + % example, to count as an @ifset for nesting.) + \long\def\doignoretextyyy##1^^M@#1##2\_STOP_{\doignoreyyy{##2}\_STOP_}% + % + % And now expand that command. + \obeylines % + \doignoretext ^^M% + }% +} + +\def\doignoreyyy#1{% + \def\temp{#1}% + \ifx\temp\empty % Nothing found. + \let\next\doignoretextzzz + \else % Found a nested condition, ... + \advance\doignorecount by 1 + \let\next\doignoretextyyy % ..., look for another. + % If we're here, #1 ends with ^^M\ifinfo (for example). + \fi + \next #1% the token \_STOP_ is present just after this macro. +} + +% We have to swallow the remaining "\_STOP_". +% +\def\doignoretextzzz#1{% + \ifnum\doignorecount = 0 % We have just found the outermost @end. + \let\next\enddoignore + \else % Still inside a nested condition. + \advance\doignorecount by -1 + \let\next\doignoretext % Look for the next @end. + \fi + \next +} + +% Finish off ignored text. +\def\enddoignore{\endgroup\ignorespaces} + + +% @set VAR sets the variable VAR to an empty value. +% @set VAR REST-OF-LINE sets VAR to the value REST-OF-LINE. +% +% Since we want to separate VAR from REST-OF-LINE (which might be +% empty), we can't just use \parsearg; we have to insert a space of our +% own to delimit the rest of the line, and then take it out again if we +% didn't need it. +% We rely on the fact that \parsearg sets \catcode`\ =10. +% +\parseargdef\set{\setyyy#1 \endsetyyy} +\def\setyyy#1 #2\endsetyyy{% + {% + \makevalueexpandable + \def\temp{#2}% + \edef\next{\gdef\makecsname{SET#1}}% + \ifx\temp\empty + \next{}% + \else + \setzzz#2\endsetzzz + \fi + }% +} +% Remove the trailing space \setxxx inserted. +\def\setzzz#1 \endsetzzz{\next{#1}} + +% @clear VAR clears (i.e., unsets) the variable VAR. +% +\parseargdef\clear{% + {% + \makevalueexpandable + \global\expandafter\let\csname SET#1\endcsname=\relax + }% +} + +% @value{foo} gets the text saved in variable foo. +\def\value{\begingroup\makevalueexpandable\valuexxx} +\def\valuexxx#1{\expandablevalue{#1}\endgroup} +{ + \catcode`\- = \active \catcode`\_ = \active + % + \gdef\makevalueexpandable{% + \let\value = \expandablevalue + % We don't want these characters active, ... + \catcode`\-=\other \catcode`\_=\other + % ..., but we might end up with active ones in the argument if + % we're called from @code, as @code{@value{foo-bar_}}, though. + % So \let them to their normal equivalents. + \let-\realdash \let_\normalunderscore + } +} + +% We have this subroutine so that we can handle at least some @value's +% properly in indexes (we call \makevalueexpandable in \indexdummies). +% The command has to be fully expandable (if the variable is set), since +% the result winds up in the index file. This means that if the +% variable's value contains other Texinfo commands, it's almost certain +% it will fail (although perhaps we could fix that with sufficient work +% to do a one-level expansion on the result, instead of complete). +% +\def\expandablevalue#1{% + \expandafter\ifx\csname SET#1\endcsname\relax + {[No value for ``#1'']}% + \message{Variable `#1', used in @value, is not set.}% + \else + \csname SET#1\endcsname + \fi +} + +% @ifset VAR ... @end ifset reads the `...' iff VAR has been defined +% with @set. +% +% To get special treatment of `@end ifset,' call \makeond and the redefine. +% +\makecond{ifset} +\def\ifset{\parsearg{\doifset{\let\next=\ifsetfail}}} +\def\doifset#1#2{% + {% + \makevalueexpandable + \let\next=\empty + \expandafter\ifx\csname SET#2\endcsname\relax + #1% If not set, redefine \next. + \fi + \expandafter + }\next +} +\def\ifsetfail{\doignore{ifset}} + +% @ifclear VAR ... @end ifclear reads the `...' iff VAR has never been +% defined with @set, or has been undefined with @clear. +% +% The `\else' inside the `\doifset' parameter is a trick to reuse the +% above code: if the variable is not set, do nothing, if it is set, +% then redefine \next to \ifclearfail. +% +\makecond{ifclear} +\def\ifclear{\parsearg{\doifset{\else \let\next=\ifclearfail}}} +\def\ifclearfail{\doignore{ifclear}} + +% @dircategory CATEGORY -- specify a category of the dir file +% which this file should belong to. Ignore this in TeX. +\let\dircategory=\comment + +% @defininfoenclose. +\let\definfoenclose=\comment + + +\message{indexing,} +% Index generation facilities + +% Define \newwrite to be identical to plain tex's \newwrite +% except not \outer, so it can be used within macros and \if's. +\edef\newwrite{\makecsname{ptexnewwrite}} + +% \newindex {foo} defines an index named foo. +% It automatically defines \fooindex such that +% \fooindex ...rest of line... puts an entry in the index foo. +% It also defines \fooindfile to be the number of the output channel for +% the file that accumulates this index. The file's extension is foo. +% The name of an index should be no more than 2 characters long +% for the sake of vms. +% +\def\newindex#1{% + \iflinks + \expandafter\newwrite \csname#1indfile\endcsname + \openout \csname#1indfile\endcsname \jobname.#1 % Open the file + \fi + \expandafter\xdef\csname#1index\endcsname{% % Define @#1index + \noexpand\doindex{#1}} +} + +% @defindex foo == \newindex{foo} +% +\def\defindex{\parsearg\newindex} + +% Define @defcodeindex, like @defindex except put all entries in @code. +% +\def\defcodeindex{\parsearg\newcodeindex} +% +\def\newcodeindex#1{% + \iflinks + \expandafter\newwrite \csname#1indfile\endcsname + \openout \csname#1indfile\endcsname \jobname.#1 + \fi + \expandafter\xdef\csname#1index\endcsname{% + \noexpand\docodeindex{#1}}% +} + + +% @synindex foo bar makes index foo feed into index bar. +% Do this instead of @defindex foo if you don't want it as a separate index. +% +% @syncodeindex foo bar similar, but put all entries made for index foo +% inside @code. +% +\def\synindex#1 #2 {\dosynindex\doindex{#1}{#2}} +\def\syncodeindex#1 #2 {\dosynindex\docodeindex{#1}{#2}} + +% #1 is \doindex or \docodeindex, #2 the index getting redefined (foo), +% #3 the target index (bar). +\def\dosynindex#1#2#3{% + % Only do \closeout if we haven't already done it, else we'll end up + % closing the target index. + \expandafter \ifx\csname donesynindex#2\endcsname \undefined + % The \closeout helps reduce unnecessary open files; the limit on the + % Acorn RISC OS is a mere 16 files. + \expandafter\closeout\csname#2indfile\endcsname + \expandafter\let\csname\donesynindex#2\endcsname = 1 + \fi + % redefine \fooindfile: + \expandafter\let\expandafter\temp\expandafter=\csname#3indfile\endcsname + \expandafter\let\csname#2indfile\endcsname=\temp + % redefine \fooindex: + \expandafter\xdef\csname#2index\endcsname{\noexpand#1{#3}}% +} + +% Define \doindex, the driver for all \fooindex macros. +% Argument #1 is generated by the calling \fooindex macro, +% and it is "foo", the name of the index. + +% \doindex just uses \parsearg; it calls \doind for the actual work. +% This is because \doind is more useful to call from other macros. + +% There is also \dosubind {index}{topic}{subtopic} +% which makes an entry in a two-level index such as the operation index. + +\def\doindex#1{\edef\indexname{#1}\parsearg\singleindexer} +\def\singleindexer #1{\doind{\indexname}{#1}} + +% like the previous two, but they put @code around the argument. +\def\docodeindex#1{\edef\indexname{#1}\parsearg\singlecodeindexer} +\def\singlecodeindexer #1{\doind{\indexname}{\code{#1}}} + +% Take care of Texinfo commands that can appear in an index entry. +% Since there are some commands we want to expand, and others we don't, +% we have to laboriously prevent expansion for those that we don't. +% +\def\indexdummies{% + \def\@{@}% change to @@ when we switch to @ as escape char in index files. + \def\ {\realbackslash\space }% + % Need these in case \tex is in effect and \{ is a \delimiter again. + % But can't use \lbracecmd and \rbracecmd because texindex assumes + % braces and backslashes are used only as delimiters. + \let\{ = \mylbrace + \let\} = \myrbrace + % + % \definedummyword defines \#1 as \realbackslash #1\space, thus + % effectively preventing its expansion. This is used only for control + % words, not control letters, because the \space would be incorrect + % for control characters, but is needed to separate the control word + % from whatever follows. + % + % For control letters, we have \definedummyletter, which omits the + % space. + % + % These can be used both for control words that take an argument and + % those that do not. If it is followed by {arg} in the input, then + % that will dutifully get written to the index (or wherever). + % + \def\definedummyword##1{% + \expandafter\def\csname ##1\endcsname{\realbackslash ##1\space}% + }% + \def\definedummyletter##1{% + \expandafter\def\csname ##1\endcsname{\realbackslash ##1}% + }% + \let\definedummyaccent\definedummyletter + % + % Do the redefinitions. + \commondummies +} + +% For the aux and toc files, @ is the escape character. So we want to +% redefine everything using @ as the escape character (instead of +% \realbackslash, still used for index files). When everything uses @, +% this will be simpler. +% +\def\atdummies{% + \def\@{@@}% + \def\ {@ }% + \let\{ = \lbraceatcmd + \let\} = \rbraceatcmd + % + % (See comments in \indexdummies.) + \def\definedummyword##1{% + \expandafter\def\csname ##1\endcsname{@##1\space}% + }% + \def\definedummyletter##1{% + \expandafter\def\csname ##1\endcsname{@##1}% + }% + \let\definedummyaccent\definedummyletter + % + % Do the redefinitions. + \commondummies +} + +% Called from \indexdummies and \atdummies. \definedummyword and +% \definedummyletter must be defined first. +% +\def\commondummies{% + % + \normalturnoffactive + % + \commondummiesnofonts + % + \definedummyletter{_}% + % + % Non-English letters. + \definedummyword{AA}% + \definedummyword{AE}% + \definedummyword{L}% + \definedummyword{OE}% + \definedummyword{O}% + \definedummyword{aa}% + \definedummyword{ae}% + \definedummyword{l}% + \definedummyword{oe}% + \definedummyword{o}% + \definedummyword{ss}% + \definedummyword{exclamdown}% + \definedummyword{questiondown}% + \definedummyword{ordf}% + \definedummyword{ordm}% + % + % Although these internal commands shouldn't show up, sometimes they do. + \definedummyword{bf}% + \definedummyword{gtr}% + \definedummyword{hat}% + \definedummyword{less}% + \definedummyword{sf}% + \definedummyword{sl}% + \definedummyword{tclose}% + \definedummyword{tt}% + % + \definedummyword{LaTeX}% + \definedummyword{TeX}% + % + % Assorted special characters. + \definedummyword{bullet}% + \definedummyword{comma}% + \definedummyword{copyright}% + \definedummyword{registeredsymbol}% + \definedummyword{dots}% + \definedummyword{enddots}% + \definedummyword{equiv}% + \definedummyword{error}% + \definedummyword{euro}% + \definedummyword{expansion}% + \definedummyword{minus}% + \definedummyword{pounds}% + \definedummyword{point}% + \definedummyword{print}% + \definedummyword{result}% + % + % Handle some cases of @value -- where it does not contain any + % (non-fully-expandable) commands. + \makevalueexpandable + % + % Normal spaces, not active ones. + \unsepspaces + % + % No macro expansion. + \turnoffmacros +} + +% \commondummiesnofonts: common to \commondummies and \indexnofonts. +% +% Better have this without active chars. +{ + \catcode`\~=\other + \gdef\commondummiesnofonts{% + % Control letters and accents. + \definedummyletter{!}% + \definedummyaccent{"}% + \definedummyaccent{'}% + \definedummyletter{*}% + \definedummyaccent{,}% + \definedummyletter{.}% + \definedummyletter{/}% + \definedummyletter{:}% + \definedummyaccent{=}% + \definedummyletter{?}% + \definedummyaccent{^}% + \definedummyaccent{`}% + \definedummyaccent{~}% + \definedummyword{u}% + \definedummyword{v}% + \definedummyword{H}% + \definedummyword{dotaccent}% + \definedummyword{ringaccent}% + \definedummyword{tieaccent}% + \definedummyword{ubaraccent}% + \definedummyword{udotaccent}% + \definedummyword{dotless}% + % + % Texinfo font commands. + \definedummyword{b}% + \definedummyword{i}% + \definedummyword{r}% + \definedummyword{sc}% + \definedummyword{t}% + % + % Commands that take arguments. + \definedummyword{acronym}% + \definedummyword{cite}% + \definedummyword{code}% + \definedummyword{command}% + \definedummyword{dfn}% + \definedummyword{emph}% + \definedummyword{env}% + \definedummyword{file}% + \definedummyword{kbd}% + \definedummyword{key}% + \definedummyword{math}% + \definedummyword{option}% + \definedummyword{samp}% + \definedummyword{strong}% + \definedummyword{tie}% + \definedummyword{uref}% + \definedummyword{url}% + \definedummyword{var}% + \definedummyword{verb}% + \definedummyword{w}% + } +} + +% \indexnofonts is used when outputting the strings to sort the index +% by, and when constructing control sequence names. It eliminates all +% control sequences and just writes whatever the best ASCII sort string +% would be for a given command (usually its argument). +% +\def\indexnofonts{% + % Accent commands should become @asis. + \def\definedummyaccent##1{% + \expandafter\let\csname ##1\endcsname\asis + }% + % We can just ignore other control letters. + \def\definedummyletter##1{% + \expandafter\def\csname ##1\endcsname{}% + }% + % Hopefully, all control words can become @asis. + \let\definedummyword\definedummyaccent + % + \commondummiesnofonts + % + % Don't no-op \tt, since it isn't a user-level command + % and is used in the definitions of the active chars like <, >, |, etc. + % Likewise with the other plain tex font commands. + %\let\tt=\asis + % + \def\ { }% + \def\@{@}% + % how to handle braces? + \def\_{\normalunderscore}% + % + % Non-English letters. + \def\AA{AA}% + \def\AE{AE}% + \def\L{L}% + \def\OE{OE}% + \def\O{O}% + \def\aa{aa}% + \def\ae{ae}% + \def\l{l}% + \def\oe{oe}% + \def\o{o}% + \def\ss{ss}% + \def\exclamdown{!}% + \def\questiondown{?}% + \def\ordf{a}% + \def\ordm{o}% + % + \def\LaTeX{LaTeX}% + \def\TeX{TeX}% + % + % Assorted special characters. + % (The following {} will end up in the sort string, but that's ok.) + \def\bullet{bullet}% + \def\comma{,}% + \def\copyright{copyright}% + \def\registeredsymbol{R}% + \def\dots{...}% + \def\enddots{...}% + \def\equiv{==}% + \def\error{error}% + \def\euro{euro}% + \def\expansion{==>}% + \def\minus{-}% + \def\pounds{pounds}% + \def\point{.}% + \def\print{-|}% + \def\result{=>}% + % + % Don't write macro names. + \emptyusermacros +} + +\let\indexbackslash=0 %overridden during \printindex. +\let\SETmarginindex=\relax % put index entries in margin (undocumented)? + +% Most index entries go through here, but \dosubind is the general case. +% #1 is the index name, #2 is the entry text. +\def\doind#1#2{\dosubind{#1}{#2}{}} + +% Workhorse for all \fooindexes. +% #1 is name of index, #2 is stuff to put there, #3 is subentry -- +% empty if called from \doind, as we usually are (the main exception +% is with most defuns, which call us directly). +% +\def\dosubind#1#2#3{% + \iflinks + {% + % Store the main index entry text (including the third arg). + \toks0 = {#2}% + % If third arg is present, precede it with a space. + \def\thirdarg{#3}% + \ifx\thirdarg\empty \else + \toks0 = \expandafter{\the\toks0 \space #3}% + \fi + % + \edef\writeto{\csname#1indfile\endcsname}% + % + \ifvmode + \dosubindsanitize + \else + \dosubindwrite + \fi + }% + \fi +} + +% Write the entry in \toks0 to the index file: +% +\def\dosubindwrite{% + % Put the index entry in the margin if desired. + \ifx\SETmarginindex\relax\else + \insert\margin{\hbox{\vrule height8pt depth3pt width0pt \the\toks0}}% + \fi + % + % Remember, we are within a group. + \indexdummies % Must do this here, since \bf, etc expand at this stage + \escapechar=`\\ + \def\backslashcurfont{\indexbackslash}% \indexbackslash isn't defined now + % so it will be output as is; and it will print as backslash. + % + % Process the index entry with all font commands turned off, to + % get the string to sort by. + {\indexnofonts + \edef\temp{\the\toks0}% need full expansion + \xdef\indexsorttmp{\temp}% + }% + % + % Set up the complete index entry, with both the sort key and + % the original text, including any font commands. We write + % three arguments to \entry to the .?? file (four in the + % subentry case), texindex reduces to two when writing the .??s + % sorted result. + \edef\temp{% + \write\writeto{% + \string\entry{\indexsorttmp}{\noexpand\folio}{\the\toks0}}% + }% + \temp +} + +% Take care of unwanted page breaks: +% +% If a skip is the last thing on the list now, preserve it +% by backing up by \lastskip, doing the \write, then inserting +% the skip again. Otherwise, the whatsit generated by the +% \write will make \lastskip zero. The result is that sequences +% like this: +% @end defun +% @tindex whatever +% @defun ... +% will have extra space inserted, because the \medbreak in the +% start of the @defun won't see the skip inserted by the @end of +% the previous defun. +% +% But don't do any of this if we're not in vertical mode. We +% don't want to do a \vskip and prematurely end a paragraph. +% +% Avoid page breaks due to these extra skips, too. +% +% But wait, there is a catch there: +% We'll have to check whether \lastskip is zero skip. \ifdim is not +% sufficient for this purpose, as it ignores stretch and shrink parts +% of the skip. The only way seems to be to check the textual +% representation of the skip. +% +% The following is almost like \def\zeroskipmacro{0.0pt} except that +% the ``p'' and ``t'' characters have catcode \other, not 11 (letter). +% +\edef\zeroskipmacro{\expandafter\the\csname z@skip\endcsname} +% +% ..., ready, GO: +% +\def\dosubindsanitize{% + % \lastskip and \lastpenalty cannot both be nonzero simultaneously. + \skip0 = \lastskip + \edef\lastskipmacro{\the\lastskip}% + \count255 = \lastpenalty + % + % If \lastskip is nonzero, that means the last item was a + % skip. And since a skip is discardable, that means this + % -\skip0 glue we're inserting is preceded by a + % non-discardable item, therefore it is not a potential + % breakpoint, therefore no \nobreak needed. + \ifx\lastskipmacro\zeroskipmacro + \else + \vskip-\skip0 + \fi + % + \dosubindwrite + % + \ifx\lastskipmacro\zeroskipmacro + % If \lastskip was zero, perhaps the last item was a penalty, and + % perhaps it was >=10000, e.g., a \nobreak. In that case, we want + % to re-insert the same penalty (values >10000 are used for various + % signals); since we just inserted a non-discardable item, any + % following glue (such as a \parskip) would be a breakpoint. For example: + % + % @deffn deffn-whatever + % @vindex index-whatever + % Description. + % would allow a break between the index-whatever whatsit + % and the "Description." paragraph. + \ifnum\count255>9999 \penalty\count255 \fi + \else + % On the other hand, if we had a nonzero \lastskip, + % this make-up glue would be preceded by a non-discardable item + % (the whatsit from the \write), so we must insert a \nobreak. + \nobreak\vskip\skip0 + \fi +} + +% The index entry written in the file actually looks like +% \entry {sortstring}{page}{topic} +% or +% \entry {sortstring}{page}{topic}{subtopic} +% The texindex program reads in these files and writes files +% containing these kinds of lines: +% \initial {c} +% before the first topic whose initial is c +% \entry {topic}{pagelist} +% for a topic that is used without subtopics +% \primary {topic} +% for the beginning of a topic that is used with subtopics +% \secondary {subtopic}{pagelist} +% for each subtopic. + +% Define the user-accessible indexing commands +% @findex, @vindex, @kindex, @cindex. + +\def\findex {\fnindex} +\def\kindex {\kyindex} +\def\cindex {\cpindex} +\def\vindex {\vrindex} +\def\tindex {\tpindex} +\def\pindex {\pgindex} + +\def\cindexsub {\begingroup\obeylines\cindexsub} +{\obeylines % +\gdef\cindexsub "#1" #2^^M{\endgroup % +\dosubind{cp}{#2}{#1}}} + +% Define the macros used in formatting output of the sorted index material. + +% @printindex causes a particular index (the ??s file) to get printed. +% It does not print any chapter heading (usually an @unnumbered). +% +\parseargdef\printindex{\begingroup + \dobreak \chapheadingskip{10000}% + % + \smallfonts \rm + \tolerance = 9500 + \everypar = {}% don't want the \kern\-parindent from indentation suppression. + % + % See if the index file exists and is nonempty. + % Change catcode of @ here so that if the index file contains + % \initial {@} + % as its first line, TeX doesn't complain about mismatched braces + % (because it thinks @} is a control sequence). + \catcode`\@ = 11 + \openin 1 \jobname.#1s + \ifeof 1 + % \enddoublecolumns gets confused if there is no text in the index, + % and it loses the chapter title and the aux file entries for the + % index. The easiest way to prevent this problem is to make sure + % there is some text. + \putwordIndexNonexistent + \else + % + % If the index file exists but is empty, then \openin leaves \ifeof + % false. We have to make TeX try to read something from the file, so + % it can discover if there is anything in it. + \read 1 to \temp + \ifeof 1 + \putwordIndexIsEmpty + \else + % Index files are almost Texinfo source, but we use \ as the escape + % character. It would be better to use @, but that's too big a change + % to make right now. + \def\indexbackslash{\backslashcurfont}% + \catcode`\\ = 0 + \escapechar = `\\ + \begindoublecolumns + \input \jobname.#1s + \enddoublecolumns + \fi + \fi + \closein 1 +\endgroup} + +% These macros are used by the sorted index file itself. +% Change them to control the appearance of the index. + +\def\initial#1{{% + % Some minor font changes for the special characters. + \let\tentt=\sectt \let\tt=\sectt \let\sf=\sectt + % + % Remove any glue we may have, we'll be inserting our own. + \removelastskip + % + % We like breaks before the index initials, so insert a bonus. + \nobreak + \vskip 0pt plus 3\baselineskip + \penalty 0 + \vskip 0pt plus -3\baselineskip + % + % Typeset the initial. Making this add up to a whole number of + % baselineskips increases the chance of the dots lining up from column + % to column. It still won't often be perfect, because of the stretch + % we need before each entry, but it's better. + % + % No shrink because it confuses \balancecolumns. + \vskip 1.67\baselineskip plus .5\baselineskip + \leftline{\secbf #1}% + % Do our best not to break after the initial. + \nobreak + \vskip .33\baselineskip plus .1\baselineskip +}} + +% \entry typesets a paragraph consisting of the text (#1), dot leaders, and +% then page number (#2) flushed to the right margin. It is used for index +% and table of contents entries. The paragraph is indented by \leftskip. +% +% A straightforward implementation would start like this: +% \def\entry#1#2{... +% But this frozes the catcodes in the argument, and can cause problems to +% @code, which sets - active. This problem was fixed by a kludge--- +% ``-'' was active throughout whole index, but this isn't really right. +% +% The right solution is to prevent \entry from swallowing the whole text. +% --kasal, 21nov03 +\def\entry{% + \begingroup + % + % Start a new paragraph if necessary, so our assignments below can't + % affect previous text. + \par + % + % Do not fill out the last line with white space. + \parfillskip = 0in + % + % No extra space above this paragraph. + \parskip = 0in + % + % Do not prefer a separate line ending with a hyphen to fewer lines. + \finalhyphendemerits = 0 + % + % \hangindent is only relevant when the entry text and page number + % don't both fit on one line. In that case, bob suggests starting the + % dots pretty far over on the line. Unfortunately, a large + % indentation looks wrong when the entry text itself is broken across + % lines. So we use a small indentation and put up with long leaders. + % + % \hangafter is reset to 1 (which is the value we want) at the start + % of each paragraph, so we need not do anything with that. + \hangindent = 2em + % + % When the entry text needs to be broken, just fill out the first line + % with blank space. + \rightskip = 0pt plus1fil + % + % A bit of stretch before each entry for the benefit of balancing + % columns. + \vskip 0pt plus1pt + % + % Swallow the left brace of the text (first parameter): + \afterassignment\doentry + \let\temp = +} +\def\doentry{% + \bgroup % Instead of the swallowed brace. + \noindent + \aftergroup\finishentry + % And now comes the text of the entry. +} +\def\finishentry#1{% + % #1 is the page number. + % + % The following is kludged to not output a line of dots in the index if + % there are no page numbers. The next person who breaks this will be + % cursed by a Unix daemon. + \def\tempa{{\rm }}% + \def\tempb{#1}% + \edef\tempc{\tempa}% + \edef\tempd{\tempb}% + \ifx\tempc\tempd + \ % + \else + % + % If we must, put the page number on a line of its own, and fill out + % this line with blank space. (The \hfil is overwhelmed with the + % fill leaders glue in \indexdotfill if the page number does fit.) + \hfil\penalty50 + \null\nobreak\indexdotfill % Have leaders before the page number. + % + % The `\ ' here is removed by the implicit \unskip that TeX does as + % part of (the primitive) \par. Without it, a spurious underfull + % \hbox ensues. + \ifpdf + \pdfgettoks#1.% + \ \the\toksA + \else + \ #1% + \fi + \fi + \par + \endgroup +} + +% Like \dotfill except takes at least 1 em. +\def\indexdotfill{\cleaders + \hbox{$\mathsurround=0pt \mkern1.5mu ${\it .}$ \mkern1.5mu$}\hskip 1em plus 1fill} + +\def\primary #1{\line{#1\hfil}} + +\newskip\secondaryindent \secondaryindent=0.5cm +\def\secondary#1#2{{% + \parfillskip=0in + \parskip=0in + \hangindent=1in + \hangafter=1 + \noindent\hskip\secondaryindent\hbox{#1}\indexdotfill + \ifpdf + \pdfgettoks#2.\ \the\toksA % The page number ends the paragraph. + \else + #2 + \fi + \par +}} + +% Define two-column mode, which we use to typeset indexes. +% Adapted from the TeXbook, page 416, which is to say, +% the manmac.tex format used to print the TeXbook itself. +\catcode`\@=11 + +\newbox\partialpage +\newdimen\doublecolumnhsize + +\def\begindoublecolumns{\begingroup % ended by \enddoublecolumns + % Grab any single-column material above us. + \output = {% + % + % Here is a possibility not foreseen in manmac: if we accumulate a + % whole lot of material, we might end up calling this \output + % routine twice in a row (see the doublecol-lose test, which is + % essentially a couple of indexes with @setchapternewpage off). In + % that case we just ship out what is in \partialpage with the normal + % output routine. Generally, \partialpage will be empty when this + % runs and this will be a no-op. See the indexspread.tex test case. + \ifvoid\partialpage \else + \onepageout{\pagecontents\partialpage}% + \fi + % + \global\setbox\partialpage = \vbox{% + % Unvbox the main output page. + \unvbox\PAGE + \kern-\topskip \kern\baselineskip + }% + }% + \eject % run that output routine to set \partialpage + % + % Use the double-column output routine for subsequent pages. + \output = {\doublecolumnout}% + % + % Change the page size parameters. We could do this once outside this + % routine, in each of @smallbook, @afourpaper, and the default 8.5x11 + % format, but then we repeat the same computation. Repeating a couple + % of assignments once per index is clearly meaningless for the + % execution time, so we may as well do it in one place. + % + % First we halve the line length, less a little for the gutter between + % the columns. We compute the gutter based on the line length, so it + % changes automatically with the paper format. The magic constant + % below is chosen so that the gutter has the same value (well, +-<1pt) + % as it did when we hard-coded it. + % + % We put the result in a separate register, \doublecolumhsize, so we + % can restore it in \pagesofar, after \hsize itself has (potentially) + % been clobbered. + % + \doublecolumnhsize = \hsize + \advance\doublecolumnhsize by -.04154\hsize + \divide\doublecolumnhsize by 2 + \hsize = \doublecolumnhsize + % + % Double the \vsize as well. (We don't need a separate register here, + % since nobody clobbers \vsize.) + \vsize = 2\vsize +} + +% The double-column output routine for all double-column pages except +% the last. +% +\def\doublecolumnout{% + \splittopskip=\topskip \splitmaxdepth=\maxdepth + % Get the available space for the double columns -- the normal + % (undoubled) page height minus any material left over from the + % previous page. + \dimen@ = \vsize + \divide\dimen@ by 2 + \advance\dimen@ by -\ht\partialpage + % + % box0 will be the left-hand column, box2 the right. + \setbox0=\vsplit255 to\dimen@ \setbox2=\vsplit255 to\dimen@ + \onepageout\pagesofar + \unvbox255 + \penalty\outputpenalty +} +% +% Re-output the contents of the output page -- any previous material, +% followed by the two boxes we just split, in box0 and box2. +\def\pagesofar{% + \unvbox\partialpage + % + \hsize = \doublecolumnhsize + \wd0=\hsize \wd2=\hsize + \hbox to\pagewidth{\box0\hfil\box2}% +} +% +% All done with double columns. +\def\enddoublecolumns{% + \output = {% + % Split the last of the double-column material. Leave it on the + % current page, no automatic page break. + \balancecolumns + % + % If we end up splitting too much material for the current page, + % though, there will be another page break right after this \output + % invocation ends. Having called \balancecolumns once, we do not + % want to call it again. Therefore, reset \output to its normal + % definition right away. (We hope \balancecolumns will never be + % called on to balance too much material, but if it is, this makes + % the output somewhat more palatable.) + \global\output = {\onepageout{\pagecontents\PAGE}}% + }% + \eject + \endgroup % started in \begindoublecolumns + % + % \pagegoal was set to the doubled \vsize above, since we restarted + % the current page. We're now back to normal single-column + % typesetting, so reset \pagegoal to the normal \vsize (after the + % \endgroup where \vsize got restored). + \pagegoal = \vsize +} +% +% Called at the end of the double column material. +\def\balancecolumns{% + \setbox0 = \vbox{\unvbox255}% like \box255 but more efficient, see p.120. + \dimen@ = \ht0 + \advance\dimen@ by \topskip + \advance\dimen@ by-\baselineskip + \divide\dimen@ by 2 % target to split to + %debug\message{final 2-column material height=\the\ht0, target=\the\dimen@.}% + \splittopskip = \topskip + % Loop until we get a decent breakpoint. + {% + \vbadness = 10000 + \loop + \global\setbox3 = \copy0 + \global\setbox1 = \vsplit3 to \dimen@ + \ifdim\ht3>\dimen@ + \global\advance\dimen@ by 1pt + \repeat + }% + %debug\message{split to \the\dimen@, column heights: \the\ht1, \the\ht3.}% + \setbox0=\vbox to\dimen@{\unvbox1}% + \setbox2=\vbox to\dimen@{\unvbox3}% + % + \pagesofar +} +\catcode`\@ = \other + + +\message{sectioning,} +% Chapters, sections, etc. + +% \unnumberedno is an oxymoron, of course. But we count the unnumbered +% sections so that we can refer to them unambiguously in the pdf +% outlines by their "section number". We avoid collisions with chapter +% numbers by starting them at 10000. (If a document ever has 10000 +% chapters, we're in trouble anyway, I'm sure.) +\newcount\unnumberedno \unnumberedno = 10000 +\newcount\chapno +\newcount\secno \secno=0 +\newcount\subsecno \subsecno=0 +\newcount\subsubsecno \subsubsecno=0 + +% This counter is funny since it counts through charcodes of letters A, B, ... +\newcount\appendixno \appendixno = `\@ +% +% \def\appendixletter{\char\the\appendixno} +% We do the following ugly conditional instead of the above simple +% construct for the sake of pdftex, which needs the actual +% letter in the expansion, not just typeset. +% +\def\appendixletter{% + \ifnum\appendixno=`A A% + \else\ifnum\appendixno=`B B% + \else\ifnum\appendixno=`C C% + \else\ifnum\appendixno=`D D% + \else\ifnum\appendixno=`E E% + \else\ifnum\appendixno=`F F% + \else\ifnum\appendixno=`G G% + \else\ifnum\appendixno=`H H% + \else\ifnum\appendixno=`I I% + \else\ifnum\appendixno=`J J% + \else\ifnum\appendixno=`K K% + \else\ifnum\appendixno=`L L% + \else\ifnum\appendixno=`M M% + \else\ifnum\appendixno=`N N% + \else\ifnum\appendixno=`O O% + \else\ifnum\appendixno=`P P% + \else\ifnum\appendixno=`Q Q% + \else\ifnum\appendixno=`R R% + \else\ifnum\appendixno=`S S% + \else\ifnum\appendixno=`T T% + \else\ifnum\appendixno=`U U% + \else\ifnum\appendixno=`V V% + \else\ifnum\appendixno=`W W% + \else\ifnum\appendixno=`X X% + \else\ifnum\appendixno=`Y Y% + \else\ifnum\appendixno=`Z Z% + % The \the is necessary, despite appearances, because \appendixletter is + % expanded while writing the .toc file. \char\appendixno is not + % expandable, thus it is written literally, thus all appendixes come out + % with the same letter (or @) in the toc without it. + \else\char\the\appendixno + \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi + \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi} + +% Each @chapter defines this as the name of the chapter. +% page headings and footings can use it. @section does likewise. +% However, they are not reliable, because we don't use marks. +\def\thischapter{} +\def\thissection{} + +\newcount\absseclevel % used to calculate proper heading level +\newcount\secbase\secbase=0 % @raisesections/@lowersections modify this count + +% @raisesections: treat @section as chapter, @subsection as section, etc. +\def\raisesections{\global\advance\secbase by -1} +\let\up=\raisesections % original BFox name + +% @lowersections: treat @chapter as section, @section as subsection, etc. +\def\lowersections{\global\advance\secbase by 1} +\let\down=\lowersections % original BFox name + +% we only have subsub. +\chardef\maxseclevel = 3 +% +% A numbered section within an unnumbered changes to unnumbered too. +% To achive this, remember the "biggest" unnum. sec. we are currently in: +\chardef\unmlevel = \maxseclevel +% +% Trace whether the current chapter is an appendix or not: +% \chapheadtype is "N" or "A", unnumbered chapters are ignored. +\def\chapheadtype{N} + +% Choose a heading macro +% #1 is heading type +% #2 is heading level +% #3 is text for heading +\def\genhead#1#2#3{% + % Compute the abs. sec. level: + \absseclevel=#2 + \advance\absseclevel by \secbase + % Make sure \absseclevel doesn't fall outside the range: + \ifnum \absseclevel < 0 + \absseclevel = 0 + \else + \ifnum \absseclevel > 3 + \absseclevel = 3 + \fi + \fi + % The heading type: + \def\headtype{#1}% + \if \headtype U% + \ifnum \absseclevel < \unmlevel + \chardef\unmlevel = \absseclevel + \fi + \else + % Check for appendix sections: + \ifnum \absseclevel = 0 + \edef\chapheadtype{\headtype}% + \else + \if \headtype A\if \chapheadtype N% + \errmessage{@appendix... within a non-appendix chapter}% + \fi\fi + \fi + % Check for numbered within unnumbered: + \ifnum \absseclevel > \unmlevel + \def\headtype{U}% + \else + \chardef\unmlevel = 3 + \fi + \fi + % Now print the heading: + \if \headtype U% + \ifcase\absseclevel + \unnumberedzzz{#3}% + \or \unnumberedseczzz{#3}% + \or \unnumberedsubseczzz{#3}% + \or \unnumberedsubsubseczzz{#3}% + \fi + \else + \if \headtype A% + \ifcase\absseclevel + \appendixzzz{#3}% + \or \appendixsectionzzz{#3}% + \or \appendixsubseczzz{#3}% + \or \appendixsubsubseczzz{#3}% + \fi + \else + \ifcase\absseclevel + \chapterzzz{#3}% + \or \seczzz{#3}% + \or \numberedsubseczzz{#3}% + \or \numberedsubsubseczzz{#3}% + \fi + \fi + \fi + \suppressfirstparagraphindent +} + +% an interface: +\def\numhead{\genhead N} +\def\apphead{\genhead A} +\def\unnmhead{\genhead U} + +% @chapter, @appendix, @unnumbered. Increment top-level counter, reset +% all lower-level sectioning counters to zero. +% +% Also set \chaplevelprefix, which we prepend to @float sequence numbers +% (e.g., figures), q.v. By default (before any chapter), that is empty. +\let\chaplevelprefix = \empty +% +\outer\parseargdef\chapter{\numhead0{#1}} % normally numhead0 calls chapterzzz +\def\chapterzzz#1{% + % section resetting is \global in case the chapter is in a group, such + % as an @include file. + \global\secno=0 \global\subsecno=0 \global\subsubsecno=0 + \global\advance\chapno by 1 + % + % Used for \float. + \gdef\chaplevelprefix{\the\chapno.}% + \resetallfloatnos + % + \message{\putwordChapter\space \the\chapno}% + % + % Write the actual heading. + \chapmacro{#1}{Ynumbered}{\the\chapno}% + % + % So @section and the like are numbered underneath this chapter. + \global\let\section = \numberedsec + \global\let\subsection = \numberedsubsec + \global\let\subsubsection = \numberedsubsubsec +} + +\outer\parseargdef\appendix{\apphead0{#1}} % normally apphead0 calls appendixzzz +\def\appendixzzz#1{% + \global\secno=0 \global\subsecno=0 \global\subsubsecno=0 + \global\advance\appendixno by 1 + \gdef\chaplevelprefix{\appendixletter.}% + \resetallfloatnos + % + \def\appendixnum{\putwordAppendix\space \appendixletter}% + \message{\appendixnum}% + % + \chapmacro{#1}{Yappendix}{\appendixletter}% + % + \global\let\section = \appendixsec + \global\let\subsection = \appendixsubsec + \global\let\subsubsection = \appendixsubsubsec +} + +\outer\parseargdef\unnumbered{\unnmhead0{#1}} % normally unnmhead0 calls unnumberedzzz +\def\unnumberedzzz#1{% + \global\secno=0 \global\subsecno=0 \global\subsubsecno=0 + \global\advance\unnumberedno by 1 + % + % Since an unnumbered has no number, no prefix for figures. + \global\let\chaplevelprefix = \empty + \resetallfloatnos + % + % This used to be simply \message{#1}, but TeX fully expands the + % argument to \message. Therefore, if #1 contained @-commands, TeX + % expanded them. For example, in `@unnumbered The @cite{Book}', TeX + % expanded @cite (which turns out to cause errors because \cite is meant + % to be executed, not expanded). + % + % Anyway, we don't want the fully-expanded definition of @cite to appear + % as a result of the \message, we just want `@cite' itself. We use + % \the<toks register> to achieve this: TeX expands \the<toks> only once, + % simply yielding the contents of <toks register>. (We also do this for + % the toc entries.) + \toks0 = {#1}% + \message{(\the\toks0)}% + % + \chapmacro{#1}{Ynothing}{\the\unnumberedno}% + % + \global\let\section = \unnumberedsec + \global\let\subsection = \unnumberedsubsec + \global\let\subsubsection = \unnumberedsubsubsec +} + +% @centerchap is like @unnumbered, but the heading is centered. +\outer\parseargdef\centerchap{% + % Well, we could do the following in a group, but that would break + % an assumption that \chapmacro is called at the outermost level. + % Thus we are safer this way: --kasal, 24feb04 + \let\centerparametersmaybe = \centerparameters + \unnmhead0{#1}% + \let\centerparametersmaybe = \relax +} + +% @top is like @unnumbered. +\let\top\unnumbered + +% Sections. +\outer\parseargdef\numberedsec{\numhead1{#1}} % normally calls seczzz +\def\seczzz#1{% + \global\subsecno=0 \global\subsubsecno=0 \global\advance\secno by 1 + \sectionheading{#1}{sec}{Ynumbered}{\the\chapno.\the\secno}% +} + +\outer\parseargdef\appendixsection{\apphead1{#1}} % normally calls appendixsectionzzz +\def\appendixsectionzzz#1{% + \global\subsecno=0 \global\subsubsecno=0 \global\advance\secno by 1 + \sectionheading{#1}{sec}{Yappendix}{\appendixletter.\the\secno}% +} +\let\appendixsec\appendixsection + +\outer\parseargdef\unnumberedsec{\unnmhead1{#1}} % normally calls unnumberedseczzz +\def\unnumberedseczzz#1{% + \global\subsecno=0 \global\subsubsecno=0 \global\advance\secno by 1 + \sectionheading{#1}{sec}{Ynothing}{\the\unnumberedno.\the\secno}% +} + +% Subsections. +\outer\parseargdef\numberedsubsec{\numhead2{#1}} % normally calls numberedsubseczzz +\def\numberedsubseczzz#1{% + \global\subsubsecno=0 \global\advance\subsecno by 1 + \sectionheading{#1}{subsec}{Ynumbered}{\the\chapno.\the\secno.\the\subsecno}% +} + +\outer\parseargdef\appendixsubsec{\apphead2{#1}} % normally calls appendixsubseczzz +\def\appendixsubseczzz#1{% + \global\subsubsecno=0 \global\advance\subsecno by 1 + \sectionheading{#1}{subsec}{Yappendix}% + {\appendixletter.\the\secno.\the\subsecno}% +} + +\outer\parseargdef\unnumberedsubsec{\unnmhead2{#1}} %normally calls unnumberedsubseczzz +\def\unnumberedsubseczzz#1{% + \global\subsubsecno=0 \global\advance\subsecno by 1 + \sectionheading{#1}{subsec}{Ynothing}% + {\the\unnumberedno.\the\secno.\the\subsecno}% +} + +% Subsubsections. +\outer\parseargdef\numberedsubsubsec{\numhead3{#1}} % normally numberedsubsubseczzz +\def\numberedsubsubseczzz#1{% + \global\advance\subsubsecno by 1 + \sectionheading{#1}{subsubsec}{Ynumbered}% + {\the\chapno.\the\secno.\the\subsecno.\the\subsubsecno}% +} + +\outer\parseargdef\appendixsubsubsec{\apphead3{#1}} % normally appendixsubsubseczzz +\def\appendixsubsubseczzz#1{% + \global\advance\subsubsecno by 1 + \sectionheading{#1}{subsubsec}{Yappendix}% + {\appendixletter.\the\secno.\the\subsecno.\the\subsubsecno}% +} + +\outer\parseargdef\unnumberedsubsubsec{\unnmhead3{#1}} %normally unnumberedsubsubseczzz +\def\unnumberedsubsubseczzz#1{% + \global\advance\subsubsecno by 1 + \sectionheading{#1}{subsubsec}{Ynothing}% + {\the\unnumberedno.\the\secno.\the\subsecno.\the\subsubsecno}% +} + +% These macros control what the section commands do, according +% to what kind of chapter we are in (ordinary, appendix, or unnumbered). +% Define them by default for a numbered chapter. +\let\section = \numberedsec +\let\subsection = \numberedsubsec +\let\subsubsection = \numberedsubsubsec + +% Define @majorheading, @heading and @subheading + +% NOTE on use of \vbox for chapter headings, section headings, and such: +% 1) We use \vbox rather than the earlier \line to permit +% overlong headings to fold. +% 2) \hyphenpenalty is set to 10000 because hyphenation in a +% heading is obnoxious; this forbids it. +% 3) Likewise, headings look best if no \parindent is used, and +% if justification is not attempted. Hence \raggedright. + + +\def\majorheading{% + {\advance\chapheadingskip by 10pt \chapbreak }% + \parsearg\chapheadingzzz +} + +\def\chapheading{\chapbreak \parsearg\chapheadingzzz} +\def\chapheadingzzz#1{% + {\chapfonts \vbox{\hyphenpenalty=10000\tolerance=5000 + \parindent=0pt\raggedright + \rm #1\hfill}}% + \bigskip \par\penalty 200\relax + \suppressfirstparagraphindent +} + +% @heading, @subheading, @subsubheading. +\parseargdef\heading{\sectionheading{#1}{sec}{Yomitfromtoc}{} + \suppressfirstparagraphindent} +\parseargdef\subheading{\sectionheading{#1}{subsec}{Yomitfromtoc}{} + \suppressfirstparagraphindent} +\parseargdef\subsubheading{\sectionheading{#1}{subsubsec}{Yomitfromtoc}{} + \suppressfirstparagraphindent} + +% These macros generate a chapter, section, etc. heading only +% (including whitespace, linebreaking, etc. around it), +% given all the information in convenient, parsed form. + +%%% Args are the skip and penalty (usually negative) +\def\dobreak#1#2{\par\ifdim\lastskip<#1\removelastskip\penalty#2\vskip#1\fi} + +%%% Define plain chapter starts, and page on/off switching for it +% Parameter controlling skip before chapter headings (if needed) + +\newskip\chapheadingskip + +\def\chapbreak{\dobreak \chapheadingskip {-4000}} +\def\chappager{\par\vfill\supereject} +\def\chapoddpage{\chappager \ifodd\pageno \else \hbox to 0pt{} \chappager\fi} + +\def\setchapternewpage #1 {\csname CHAPPAG#1\endcsname} + +\def\CHAPPAGoff{% +\global\let\contentsalignmacro = \chappager +\global\let\pchapsepmacro=\chapbreak +\global\let\pagealignmacro=\chappager} + +\def\CHAPPAGon{% +\global\let\contentsalignmacro = \chappager +\global\let\pchapsepmacro=\chappager +\global\let\pagealignmacro=\chappager +\global\def\HEADINGSon{\HEADINGSsingle}} + +\def\CHAPPAGodd{% +\global\let\contentsalignmacro = \chapoddpage +\global\let\pchapsepmacro=\chapoddpage +\global\let\pagealignmacro=\chapoddpage +\global\def\HEADINGSon{\HEADINGSdouble}} + +\CHAPPAGon + +% Chapter opening. +% +% #1 is the text, #2 is the section type (Ynumbered, Ynothing, +% Yappendix, Yomitfromtoc), #3 the chapter number. +% +% To test against our argument. +\def\Ynothingkeyword{Ynothing} +\def\Yomitfromtockeyword{Yomitfromtoc} +\def\Yappendixkeyword{Yappendix} +% +\def\chapmacro#1#2#3{% + \pchapsepmacro + {% + \chapfonts \rm + % + % Have to define \thissection before calling \donoderef, because the + % xref code eventually uses it. On the other hand, it has to be called + % after \pchapsepmacro, or the headline will change too soon. + \gdef\thissection{#1}% + \gdef\thischaptername{#1}% + % + % Only insert the separating space if we have a chapter/appendix + % number, and don't print the unnumbered ``number''. + \def\temptype{#2}% + \ifx\temptype\Ynothingkeyword + \setbox0 = \hbox{}% + \def\toctype{unnchap}% + \gdef\thischapter{#1}% + \else\ifx\temptype\Yomitfromtockeyword + \setbox0 = \hbox{}% contents like unnumbered, but no toc entry + \def\toctype{omit}% + \gdef\thischapter{}% + \else\ifx\temptype\Yappendixkeyword + \setbox0 = \hbox{\putwordAppendix{} #3\enspace}% + \def\toctype{app}% + % We don't substitute the actual chapter name into \thischapter + % because we don't want its macros evaluated now. And we don't + % use \thissection because that changes with each section. + % + \xdef\thischapter{\putwordAppendix{} \appendixletter: + \noexpand\thischaptername}% + \else + \setbox0 = \hbox{#3\enspace}% + \def\toctype{numchap}% + \xdef\thischapter{\putwordChapter{} \the\chapno: + \noexpand\thischaptername}% + \fi\fi\fi + % + % Write the toc entry for this chapter. Must come before the + % \donoderef, because we include the current node name in the toc + % entry, and \donoderef resets it to empty. + \writetocentry{\toctype}{#1}{#3}% + % + % For pdftex, we have to write out the node definition (aka, make + % the pdfdest) after any page break, but before the actual text has + % been typeset. If the destination for the pdf outline is after the + % text, then jumping from the outline may wind up with the text not + % being visible, for instance under high magnification. + \donoderef{#2}% + % + % Typeset the actual heading. + \vbox{\hyphenpenalty=10000 \tolerance=5000 \parindent=0pt \raggedright + \hangindent=\wd0 \centerparametersmaybe + \unhbox0 #1\par}% + }% + \nobreak\bigskip % no page break after a chapter title + \nobreak +} + +% @centerchap -- centered and unnumbered. +\let\centerparametersmaybe = \relax +\def\centerparameters{% + \advance\rightskip by 3\rightskip + \leftskip = \rightskip + \parfillskip = 0pt +} + + +% I don't think this chapter style is supported any more, so I'm not +% updating it with the new noderef stuff. We'll see. --karl, 11aug03. +% +\def\setchapterstyle #1 {\csname CHAPF#1\endcsname} +% +\def\unnchfopen #1{% +\chapoddpage {\chapfonts \vbox{\hyphenpenalty=10000\tolerance=5000 + \parindent=0pt\raggedright + \rm #1\hfill}}\bigskip \par\nobreak +} +\def\chfopen #1#2{\chapoddpage {\chapfonts +\vbox to 3in{\vfil \hbox to\hsize{\hfil #2} \hbox to\hsize{\hfil #1} \vfil}}% +\par\penalty 5000 % +} +\def\centerchfopen #1{% +\chapoddpage {\chapfonts \vbox{\hyphenpenalty=10000\tolerance=5000 + \parindent=0pt + \hfill {\rm #1}\hfill}}\bigskip \par\nobreak +} +\def\CHAPFopen{% + \global\let\chapmacro=\chfopen + \global\let\centerchapmacro=\centerchfopen} + + +% Section titles. These macros combine the section number parts and +% call the generic \sectionheading to do the printing. +% +\newskip\secheadingskip +\def\secheadingbreak{\dobreak \secheadingskip{-1000}} + +% Subsection titles. +\newskip\subsecheadingskip +\def\subsecheadingbreak{\dobreak \subsecheadingskip{-500}} + +% Subsubsection titles. +\def\subsubsecheadingskip{\subsecheadingskip} +\def\subsubsecheadingbreak{\subsecheadingbreak} + + +% Print any size, any type, section title. +% +% #1 is the text, #2 is the section level (sec/subsec/subsubsec), #3 is +% the section type for xrefs (Ynumbered, Ynothing, Yappendix), #4 is the +% section number. +% +\def\sectionheading#1#2#3#4{% + {% + % Switch to the right set of fonts. + \csname #2fonts\endcsname \rm + % + % Insert space above the heading. + \csname #2headingbreak\endcsname + % + % Only insert the space after the number if we have a section number. + \def\sectionlevel{#2}% + \def\temptype{#3}% + % + \ifx\temptype\Ynothingkeyword + \setbox0 = \hbox{}% + \def\toctype{unn}% + \gdef\thissection{#1}% + \else\ifx\temptype\Yomitfromtockeyword + % for @headings -- no section number, don't include in toc, + % and don't redefine \thissection. + \setbox0 = \hbox{}% + \def\toctype{omit}% + \let\sectionlevel=\empty + \else\ifx\temptype\Yappendixkeyword + \setbox0 = \hbox{#4\enspace}% + \def\toctype{app}% + \gdef\thissection{#1}% + \else + \setbox0 = \hbox{#4\enspace}% + \def\toctype{num}% + \gdef\thissection{#1}% + \fi\fi\fi + % + % Write the toc entry (before \donoderef). See comments in \chfplain. + \writetocentry{\toctype\sectionlevel}{#1}{#4}% + % + % Write the node reference (= pdf destination for pdftex). + % Again, see comments in \chfplain. + \donoderef{#3}% + % + % Output the actual section heading. + \vbox{\hyphenpenalty=10000 \tolerance=5000 \parindent=0pt \raggedright + \hangindent=\wd0 % zero if no section number + \unhbox0 #1}% + }% + % Add extra space after the heading -- half of whatever came above it. + % Don't allow stretch, though. + \kern .5 \csname #2headingskip\endcsname + % + % Do not let the kern be a potential breakpoint, as it would be if it + % was followed by glue. + \nobreak + % + % We'll almost certainly start a paragraph next, so don't let that + % glue accumulate. (Not a breakpoint because it's preceded by a + % discardable item.) + \vskip-\parskip + % + % This is purely so the last item on the list is a known \penalty > + % 10000. This is so \startdefun can avoid allowing breakpoints after + % section headings. Otherwise, it would insert a valid breakpoint between: + % + % @section sec-whatever + % @deffn def-whatever + \penalty 10001 +} + + +\message{toc,} +% Table of contents. +\newwrite\tocfile + +% Write an entry to the toc file, opening it if necessary. +% Called from @chapter, etc. +% +% Example usage: \writetocentry{sec}{Section Name}{\the\chapno.\the\secno} +% We append the current node name (if any) and page number as additional +% arguments for the \{chap,sec,...}entry macros which will eventually +% read this. The node name is used in the pdf outlines as the +% destination to jump to. +% +% We open the .toc file for writing here instead of at @setfilename (or +% any other fixed time) so that @contents can be anywhere in the document. +% But if #1 is `omit', then we don't do anything. This is used for the +% table of contents chapter openings themselves. +% +\newif\iftocfileopened +\def\omitkeyword{omit}% +% +\def\writetocentry#1#2#3{% + \edef\writetoctype{#1}% + \ifx\writetoctype\omitkeyword \else + \iftocfileopened\else + \immediate\openout\tocfile = \jobname.toc + \global\tocfileopenedtrue + \fi + % + \iflinks + {\atdummies \turnoffactive + \edef\temp{% + \write\tocfile{@#1entry{#2}{#3}{\lastnode}{\noexpand\folio}}}% + \temp + } + \fi + \fi + % + % Tell \shipout to create a pdf destination on each page, if we're + % writing pdf. These are used in the table of contents. We can't + % just write one on every page because the title pages are numbered + % 1 and 2 (the page numbers aren't printed), and so are the first + % two pages of the document. Thus, we'd have two destinations named + % `1', and two named `2'. + \ifpdf \global\pdfmakepagedesttrue \fi +} + + +% These characters do not print properly in the Computer Modern roman +% fonts, so we must take special care. This is more or less redundant +% with the Texinfo input format setup at the end of this file. +% +\def\activecatcodes{% + \catcode`\"=\active + \catcode`\$=\active + \catcode`\<=\active + \catcode`\>=\active + \catcode`\\=\active + \catcode`\^=\active + \catcode`\_=\active + \catcode`\|=\active + \catcode`\~=\active +} + + +% Read the toc file, which is essentially Texinfo input. +\def\readtocfile{% + \setupdatafile + \activecatcodes + \input \jobname.toc +} + +\newskip\contentsrightmargin \contentsrightmargin=1in +\newcount\savepageno +\newcount\lastnegativepageno \lastnegativepageno = -1 + +% Prepare to read what we've written to \tocfile. +% +\def\startcontents#1{% + % If @setchapternewpage on, and @headings double, the contents should + % start on an odd page, unlike chapters. Thus, we maintain + % \contentsalignmacro in parallel with \pagealignmacro. + % From: Torbjorn Granlund <tege@matematik.su.se> + \contentsalignmacro + \immediate\closeout\tocfile + % + % Don't need to put `Contents' or `Short Contents' in the headline. + % It is abundantly clear what they are. + \def\thischapter{}% + \chapmacro{#1}{Yomitfromtoc}{}% + % + \savepageno = \pageno + \begingroup % Set up to handle contents files properly. + \raggedbottom % Worry more about breakpoints than the bottom. + \advance\hsize by -\contentsrightmargin % Don't use the full line length. + % + % Roman numerals for page numbers. + \ifnum \pageno>0 \global\pageno = \lastnegativepageno \fi +} + + +% Normal (long) toc. +\def\contents{% + \startcontents{\putwordTOC}% + \openin 1 \jobname.toc + \ifeof 1 \else + \readtocfile + \fi + \vfill \eject + \contentsalignmacro % in case @setchapternewpage odd is in effect + \ifeof 1 \else + \pdfmakeoutlines + \fi + \closein 1 + \endgroup + \lastnegativepageno = \pageno + \global\pageno = \savepageno +} + +% And just the chapters. +\def\summarycontents{% + \startcontents{\putwordShortTOC}% + % + \let\numchapentry = \shortchapentry + \let\appentry = \shortchapentry + \let\unnchapentry = \shortunnchapentry + % We want a true roman here for the page numbers. + \secfonts + \let\rm=\shortcontrm \let\bf=\shortcontbf + \let\sl=\shortcontsl \let\tt=\shortconttt + \rm + \hyphenpenalty = 10000 + \advance\baselineskip by 1pt % Open it up a little. + \def\numsecentry##1##2##3##4{} + \let\appsecentry = \numsecentry + \let\unnsecentry = \numsecentry + \let\numsubsecentry = \numsecentry + \let\appsubsecentry = \numsecentry + \let\unnsubsecentry = \numsecentry + \let\numsubsubsecentry = \numsecentry + \let\appsubsubsecentry = \numsecentry + \let\unnsubsubsecentry = \numsecentry + \openin 1 \jobname.toc + \ifeof 1 \else + \readtocfile + \fi + \closein 1 + \vfill \eject + \contentsalignmacro % in case @setchapternewpage odd is in effect + \endgroup + \lastnegativepageno = \pageno + \global\pageno = \savepageno +} +\let\shortcontents = \summarycontents + +% Typeset the label for a chapter or appendix for the short contents. +% The arg is, e.g., `A' for an appendix, or `3' for a chapter. +% +\def\shortchaplabel#1{% + % This space should be enough, since a single number is .5em, and the + % widest letter (M) is 1em, at least in the Computer Modern fonts. + % But use \hss just in case. + % (This space doesn't include the extra space that gets added after + % the label; that gets put in by \shortchapentry above.) + % + % We'd like to right-justify chapter numbers, but that looks strange + % with appendix letters. And right-justifying numbers and + % left-justifying letters looks strange when there is less than 10 + % chapters. Have to read the whole toc once to know how many chapters + % there are before deciding ... + \hbox to 1em{#1\hss}% +} + +% These macros generate individual entries in the table of contents. +% The first argument is the chapter or section name. +% The last argument is the page number. +% The arguments in between are the chapter number, section number, ... + +% Chapters, in the main contents. +\def\numchapentry#1#2#3#4{\dochapentry{#2\labelspace#1}{#4}} +% +% Chapters, in the short toc. +% See comments in \dochapentry re vbox and related settings. +\def\shortchapentry#1#2#3#4{% + \tocentry{\shortchaplabel{#2}\labelspace #1}{\doshortpageno\bgroup#4\egroup}% +} + +% Appendices, in the main contents. +% Need the word Appendix, and a fixed-size box. +% +\def\appendixbox#1{% + % We use M since it's probably the widest letter. + \setbox0 = \hbox{\putwordAppendix{} M}% + \hbox to \wd0{\putwordAppendix{} #1\hss}} +% +\def\appentry#1#2#3#4{\dochapentry{\appendixbox{#2}\labelspace#1}{#4}} + +% Unnumbered chapters. +\def\unnchapentry#1#2#3#4{\dochapentry{#1}{#4}} +\def\shortunnchapentry#1#2#3#4{\tocentry{#1}{\doshortpageno\bgroup#4\egroup}} + +% Sections. +\def\numsecentry#1#2#3#4{\dosecentry{#2\labelspace#1}{#4}} +\let\appsecentry=\numsecentry +\def\unnsecentry#1#2#3#4{\dosecentry{#1}{#4}} + +% Subsections. +\def\numsubsecentry#1#2#3#4{\dosubsecentry{#2\labelspace#1}{#4}} +\let\appsubsecentry=\numsubsecentry +\def\unnsubsecentry#1#2#3#4{\dosubsecentry{#1}{#4}} + +% And subsubsections. +\def\numsubsubsecentry#1#2#3#4{\dosubsubsecentry{#2\labelspace#1}{#4}} +\let\appsubsubsecentry=\numsubsubsecentry +\def\unnsubsubsecentry#1#2#3#4{\dosubsubsecentry{#1}{#4}} + +% This parameter controls the indentation of the various levels. +% Same as \defaultparindent. +\newdimen\tocindent \tocindent = 15pt + +% Now for the actual typesetting. In all these, #1 is the text and #2 is the +% page number. +% +% If the toc has to be broken over pages, we want it to be at chapters +% if at all possible; hence the \penalty. +\def\dochapentry#1#2{% + \penalty-300 \vskip1\baselineskip plus.33\baselineskip minus.25\baselineskip + \begingroup + \chapentryfonts + \tocentry{#1}{\dopageno\bgroup#2\egroup}% + \endgroup + \nobreak\vskip .25\baselineskip plus.1\baselineskip +} + +\def\dosecentry#1#2{\begingroup + \secentryfonts \leftskip=\tocindent + \tocentry{#1}{\dopageno\bgroup#2\egroup}% +\endgroup} + +\def\dosubsecentry#1#2{\begingroup + \subsecentryfonts \leftskip=2\tocindent + \tocentry{#1}{\dopageno\bgroup#2\egroup}% +\endgroup} + +\def\dosubsubsecentry#1#2{\begingroup + \subsubsecentryfonts \leftskip=3\tocindent + \tocentry{#1}{\dopageno\bgroup#2\egroup}% +\endgroup} + +% We use the same \entry macro as for the index entries. +\let\tocentry = \entry + +% Space between chapter (or whatever) number and the title. +\def\labelspace{\hskip1em \relax} + +\def\dopageno#1{{\rm #1}} +\def\doshortpageno#1{{\rm #1}} + +\def\chapentryfonts{\secfonts \rm} +\def\secentryfonts{\textfonts} +\def\subsecentryfonts{\textfonts} +\def\subsubsecentryfonts{\textfonts} + + +\message{environments,} +% @foo ... @end foo. + +% @point{}, @result{}, @expansion{}, @print{}, @equiv{}. +% +% Since these characters are used in examples, it should be an even number of +% \tt widths. Each \tt character is 1en, so two makes it 1em. +% +\def\point{$\star$} +\def\result{\leavevmode\raise.15ex\hbox to 1em{\hfil$\Rightarrow$\hfil}} +\def\expansion{\leavevmode\raise.1ex\hbox to 1em{\hfil$\mapsto$\hfil}} +\def\print{\leavevmode\lower.1ex\hbox to 1em{\hfil$\dashv$\hfil}} +\def\equiv{\leavevmode\lower.1ex\hbox to 1em{\hfil$\ptexequiv$\hfil}} + +% The @error{} command. +% Adapted from the TeXbook's \boxit. +% +\newbox\errorbox +% +{\tentt \global\dimen0 = 3em}% Width of the box. +\dimen2 = .55pt % Thickness of rules +% The text. (`r' is open on the right, `e' somewhat less so on the left.) +\setbox0 = \hbox{\kern-.75pt \tensf error\kern-1.5pt} +% +\setbox\errorbox=\hbox to \dimen0{\hfil + \hsize = \dimen0 \advance\hsize by -5.8pt % Space to left+right. + \advance\hsize by -2\dimen2 % Rules. + \vbox{% + \hrule height\dimen2 + \hbox{\vrule width\dimen2 \kern3pt % Space to left of text. + \vtop{\kern2.4pt \box0 \kern2.4pt}% Space above/below. + \kern3pt\vrule width\dimen2}% Space to right. + \hrule height\dimen2} + \hfil} +% +\def\error{\leavevmode\lower.7ex\copy\errorbox} + +% @tex ... @end tex escapes into raw Tex temporarily. +% One exception: @ is still an escape character, so that @end tex works. +% But \@ or @@ will get a plain tex @ character. + +\envdef\tex{% + \catcode `\\=0 \catcode `\{=1 \catcode `\}=2 + \catcode `\$=3 \catcode `\&=4 \catcode `\#=6 + \catcode `\^=7 \catcode `\_=8 \catcode `\~=\active \let~=\tie + \catcode `\%=14 + \catcode `\+=\other + \catcode `\"=\other + \catcode `\|=\other + \catcode `\<=\other + \catcode `\>=\other + \escapechar=`\\ + % + \let\b=\ptexb + \let\bullet=\ptexbullet + \let\c=\ptexc + \let\,=\ptexcomma + \let\.=\ptexdot + \let\dots=\ptexdots + \let\equiv=\ptexequiv + \let\!=\ptexexclam + \let\i=\ptexi + \let\indent=\ptexindent + \let\noindent=\ptexnoindent + \let\{=\ptexlbrace + \let\+=\tabalign + \let\}=\ptexrbrace + \let\/=\ptexslash + \let\*=\ptexstar + \let\t=\ptext + \let\frenchspacing=\plainfrenchspacing + % + \def\endldots{\mathinner{\ldots\ldots\ldots\ldots}}% + \def\enddots{\relax\ifmmode\endldots\else$\mathsurround=0pt \endldots\,$\fi}% + \def\@{@}% +} +% There is no need to define \Etex. + +% Define @lisp ... @end lisp. +% @lisp environment forms a group so it can rebind things, +% including the definition of @end lisp (which normally is erroneous). + +% Amount to narrow the margins by for @lisp. +\newskip\lispnarrowing \lispnarrowing=0.4in + +% This is the definition that ^^M gets inside @lisp, @example, and other +% such environments. \null is better than a space, since it doesn't +% have any width. +\def\lisppar{\null\endgraf} + +% This space is always present above and below environments. +\newskip\envskipamount \envskipamount = 0pt + +% Make spacing and below environment symmetrical. We use \parskip here +% to help in doing that, since in @example-like environments \parskip +% is reset to zero; thus the \afterenvbreak inserts no space -- but the +% start of the next paragraph will insert \parskip. +% +\def\aboveenvbreak{{% + % =10000 instead of <10000 because of a special case in \itemzzz and + % \sectionheading, q.v. + \ifnum \lastpenalty=10000 \else + \advance\envskipamount by \parskip + \endgraf + \ifdim\lastskip<\envskipamount + \removelastskip + % it's not a good place to break if the last penalty was \nobreak + % or better ... + \ifnum\lastpenalty<10000 \penalty-50 \fi + \vskip\envskipamount + \fi + \fi +}} + +\let\afterenvbreak = \aboveenvbreak + +% \nonarrowing is a flag. If "set", @lisp etc don't narrow margins. +\let\nonarrowing=\relax + +% @cartouche ... @end cartouche: draw rectangle w/rounded corners around +% environment contents. +\font\circle=lcircle10 +\newdimen\circthick +\newdimen\cartouter\newdimen\cartinner +\newskip\normbskip\newskip\normpskip\newskip\normlskip +\circthick=\fontdimen8\circle +% +\def\ctl{{\circle\char'013\hskip -6pt}}% 6pt from pl file: 1/2charwidth +\def\ctr{{\hskip 6pt\circle\char'010}} +\def\cbl{{\circle\char'012\hskip -6pt}} +\def\cbr{{\hskip 6pt\circle\char'011}} +\def\carttop{\hbox to \cartouter{\hskip\lskip + \ctl\leaders\hrule height\circthick\hfil\ctr + \hskip\rskip}} +\def\cartbot{\hbox to \cartouter{\hskip\lskip + \cbl\leaders\hrule height\circthick\hfil\cbr + \hskip\rskip}} +% +\newskip\lskip\newskip\rskip + +\envdef\cartouche{% + \ifhmode\par\fi % can't be in the midst of a paragraph. + \startsavinginserts + \lskip=\leftskip \rskip=\rightskip + \leftskip=0pt\rightskip=0pt % we want these *outside*. + \cartinner=\hsize \advance\cartinner by-\lskip + \advance\cartinner by-\rskip + \cartouter=\hsize + \advance\cartouter by 18.4pt % allow for 3pt kerns on either + % side, and for 6pt waste from + % each corner char, and rule thickness + \normbskip=\baselineskip \normpskip=\parskip \normlskip=\lineskip + % Flag to tell @lisp, etc., not to narrow margin. + \let\nonarrowing=\comment + \vbox\bgroup + \baselineskip=0pt\parskip=0pt\lineskip=0pt + \carttop + \hbox\bgroup + \hskip\lskip + \vrule\kern3pt + \vbox\bgroup + \kern3pt + \hsize=\cartinner + \baselineskip=\normbskip + \lineskip=\normlskip + \parskip=\normpskip + \vskip -\parskip + \comment % For explanation, see the end of \def\group. +} +\def\Ecartouche{% + \ifhmode\par\fi + \kern3pt + \egroup + \kern3pt\vrule + \hskip\rskip + \egroup + \cartbot + \egroup + \checkinserts +} + + +% This macro is called at the beginning of all the @example variants, +% inside a group. +\def\nonfillstart{% + \aboveenvbreak + \hfuzz = 12pt % Don't be fussy + \sepspaces % Make spaces be word-separators rather than space tokens. + \let\par = \lisppar % don't ignore blank lines + \obeylines % each line of input is a line of output + \parskip = 0pt + \parindent = 0pt + \emergencystretch = 0pt % don't try to avoid overfull boxes + % @cartouche defines \nonarrowing to inhibit narrowing + % at next level down. + \ifx\nonarrowing\relax + \advance \leftskip by \lispnarrowing + \exdentamount=\lispnarrowing + \fi + \let\exdent=\nofillexdent +} + +% If you want all examples etc. small: @set dispenvsize small. +% If you want even small examples the full size: @set dispenvsize nosmall. +% This affects the following displayed environments: +% @example, @display, @format, @lisp +% +\def\smallword{small} +\def\nosmallword{nosmall} +\let\SETdispenvsize\relax +\def\setnormaldispenv{% + \ifx\SETdispenvsize\smallword + \smallexamplefonts \rm + \fi +} +\def\setsmalldispenv{% + \ifx\SETdispenvsize\nosmallword + \else + \smallexamplefonts \rm + \fi +} + +% We often define two environments, @foo and @smallfoo. +% Let's do it by one command: +\def\makedispenv #1#2{ + \expandafter\envdef\csname#1\endcsname {\setnormaldispenv #2} + \expandafter\envdef\csname small#1\endcsname {\setsmalldispenv #2} + \expandafter\let\csname E#1\endcsname \afterenvbreak + \expandafter\let\csname Esmall#1\endcsname \afterenvbreak +} + +% Define two synonyms: +\def\maketwodispenvs #1#2#3{ + \makedispenv{#1}{#3} + \makedispenv{#2}{#3} +} + +% @lisp: indented, narrowed, typewriter font; @example: same as @lisp. +% +% @smallexample and @smalllisp: use smaller fonts. +% Originally contributed by Pavel@xerox. +% +\maketwodispenvs {lisp}{example}{% + \nonfillstart + \tt + \let\kbdfont = \kbdexamplefont % Allow @kbd to do something special. + \gobble % eat return +} + +% @display/@smalldisplay: same as @lisp except keep current font. +% +\makedispenv {display}{% + \nonfillstart + \gobble +} + +% @format/@smallformat: same as @display except don't narrow margins. +% +\makedispenv{format}{% + \let\nonarrowing = t% + \nonfillstart + \gobble +} + +% @flushleft: same as @format, but doesn't obey \SETdispenvsize. +\envdef\flushleft{% + \let\nonarrowing = t% + \nonfillstart + \gobble +} +\let\Eflushleft = \afterenvbreak + +% @flushright. +% +\envdef\flushright{% + \let\nonarrowing = t% + \nonfillstart + \advance\leftskip by 0pt plus 1fill + \gobble +} +\let\Eflushright = \afterenvbreak + + +% @quotation does normal linebreaking (hence we can't use \nonfillstart) +% and narrows the margins. We keep \parskip nonzero in general, since +% we're doing normal filling. So, when using \aboveenvbreak and +% \afterenvbreak, temporarily make \parskip 0. +% +\envdef\quotation{% + {\parskip=0pt \aboveenvbreak}% because \aboveenvbreak inserts \parskip + \parindent=0pt + % + % @cartouche defines \nonarrowing to inhibit narrowing at next level down. + \ifx\nonarrowing\relax + \advance\leftskip by \lispnarrowing + \advance\rightskip by \lispnarrowing + \exdentamount = \lispnarrowing + \let\nonarrowing = \relax + \fi + \parsearg\quotationlabel +} + +% We have retained a nonzero parskip for the environment, since we're +% doing normal filling. +% +\def\Equotation{% + \par + \ifx\quotationauthor\undefined\else + % indent a bit. + \leftline{\kern 2\leftskip \sl ---\quotationauthor}% + \fi + {\parskip=0pt \afterenvbreak}% +} + +% If we're given an argument, typeset it in bold with a colon after. +\def\quotationlabel#1{% + \def\temp{#1}% + \ifx\temp\empty \else + {\bf #1: }% + \fi +} + + +% LaTeX-like @verbatim...@end verbatim and @verb{<char>...<char>} +% If we want to allow any <char> as delimiter, +% we need the curly braces so that makeinfo sees the @verb command, eg: +% `@verbx...x' would look like the '@verbx' command. --janneke@gnu.org +% +% [Knuth]: Donald Ervin Knuth, 1996. The TeXbook. +% +% [Knuth] p.344; only we need to do the other characters Texinfo sets +% active too. Otherwise, they get lost as the first character on a +% verbatim line. +\def\dospecials{% + \do\ \do\\\do\{\do\}\do\$\do\&% + \do\#\do\^\do\^^K\do\_\do\^^A\do\%\do\~% + \do\<\do\>\do\|\do\@\do+\do\"% +} +% +% [Knuth] p. 380 +\def\uncatcodespecials{% + \def\do##1{\catcode`##1=\other}\dospecials} +% +% [Knuth] pp. 380,381,391 +% Disable Spanish ligatures ?` and !` of \tt font +\begingroup + \catcode`\`=\active\gdef`{\relax\lq} +\endgroup +% +% Setup for the @verb command. +% +% Eight spaces for a tab +\begingroup + \catcode`\^^I=\active + \gdef\tabeightspaces{\catcode`\^^I=\active\def^^I{\ \ \ \ \ \ \ \ }} +\endgroup +% +\def\setupverb{% + \tt % easiest (and conventionally used) font for verbatim + \def\par{\leavevmode\endgraf}% + \catcode`\`=\active + \tabeightspaces + % Respect line breaks, + % print special symbols as themselves, and + % make each space count + % must do in this order: + \obeylines \uncatcodespecials \sepspaces +} + +% Setup for the @verbatim environment +% +% Real tab expansion +\newdimen\tabw \setbox0=\hbox{\tt\space} \tabw=8\wd0 % tab amount +% +\def\starttabbox{\setbox0=\hbox\bgroup} +\begingroup + \catcode`\^^I=\active + \gdef\tabexpand{% + \catcode`\^^I=\active + \def^^I{\leavevmode\egroup + \dimen0=\wd0 % the width so far, or since the previous tab + \divide\dimen0 by\tabw + \multiply\dimen0 by\tabw % compute previous multiple of \tabw + \advance\dimen0 by\tabw % advance to next multiple of \tabw + \wd0=\dimen0 \box0 \starttabbox + }% + } +\endgroup +\def\setupverbatim{% + \nonfillstart + \advance\leftskip by -\defbodyindent + % Easiest (and conventionally used) font for verbatim + \tt + \def\par{\leavevmode\egroup\box0\endgraf}% + \catcode`\`=\active + \tabexpand + % Respect line breaks, + % print special symbols as themselves, and + % make each space count + % must do in this order: + \obeylines \uncatcodespecials \sepspaces + \everypar{\starttabbox}% +} + +% Do the @verb magic: verbatim text is quoted by unique +% delimiter characters. Before first delimiter expect a +% right brace, after last delimiter expect closing brace: +% +% \def\doverb'{'<char>#1<char>'}'{#1} +% +% [Knuth] p. 382; only eat outer {} +\begingroup + \catcode`[=1\catcode`]=2\catcode`\{=\other\catcode`\}=\other + \gdef\doverb{#1[\def\next##1#1}[##1\endgroup]\next] +\endgroup +% +\def\verb{\begingroup\setupverb\doverb} +% +% +% Do the @verbatim magic: define the macro \doverbatim so that +% the (first) argument ends when '@end verbatim' is reached, ie: +% +% \def\doverbatim#1@end verbatim{#1} +% +% For Texinfo it's a lot easier than for LaTeX, +% because texinfo's \verbatim doesn't stop at '\end{verbatim}': +% we need not redefine '\', '{' and '}'. +% +% Inspired by LaTeX's verbatim command set [latex.ltx] +% +\begingroup + \catcode`\ =\active + \obeylines % + % ignore everything up to the first ^^M, that's the newline at the end + % of the @verbatim input line itself. Otherwise we get an extra blank + % line in the output. + \xdef\doverbatim#1^^M#2@end verbatim{#2\noexpand\end\gobble verbatim}% + % We really want {...\end verbatim} in the body of the macro, but + % without the active space; thus we have to use \xdef and \gobble. +\endgroup +% +\envdef\verbatim{% + \setupverbatim\doverbatim +} +\let\Everbatim = \afterenvbreak + + +% @verbatiminclude FILE - insert text of file in verbatim environment. +% +\def\verbatiminclude{\parseargusing\filenamecatcodes\doverbatiminclude} +% +\def\doverbatiminclude#1{% + {% + \makevalueexpandable + \setupverbatim + \input #1 + \afterenvbreak + }% +} + +% @copying ... @end copying. +% Save the text away for @insertcopying later. +% +% We save the uninterpreted tokens, rather than creating a box. +% Saving the text in a box would be much easier, but then all the +% typesetting commands (@smallbook, font changes, etc.) have to be done +% beforehand -- and a) we want @copying to be done first in the source +% file; b) letting users define the frontmatter in as flexible order as +% possible is very desirable. +% +\def\copying{\checkenv{}\begingroup\scanargctxt\docopying} +\def\docopying#1@end copying{\endgroup\def\copyingtext{#1}} +% +\def\insertcopying{% + \begingroup + \parindent = 0pt % paragraph indentation looks wrong on title page + \scanexp\copyingtext + \endgroup +} + +\message{defuns,} +% @defun etc. + +\newskip\defbodyindent \defbodyindent=.4in +\newskip\defargsindent \defargsindent=50pt +\newskip\deflastargmargin \deflastargmargin=18pt + +% Start the processing of @deffn: +\def\startdefun{% + \ifnum\lastpenalty<10000 + \medbreak + \else + % If there are two @def commands in a row, we'll have a \nobreak, + % which is there to keep the function description together with its + % header. But if there's nothing but headers, we need to allow a + % break somewhere. Check specifically for penalty 10002, inserted + % by \defargscommonending, instead of 10000, since the sectioning + % commands also insert a nobreak penalty, and we don't want to allow + % a break between a section heading and a defun. + % + \ifnum\lastpenalty=10002 \penalty2000 \fi + % + % Similarly, after a section heading, do not allow a break. + % But do insert the glue. + \medskip % preceded by discardable penalty, so not a breakpoint + \fi + % + \parindent=0in + \advance\leftskip by \defbodyindent + \exdentamount=\defbodyindent +} + +\def\dodefunx#1{% + % First, check whether we are in the right environment: + \checkenv#1% + % + % As above, allow line break if we have multiple x headers in a row. + % It's not a great place, though. + \ifnum\lastpenalty=10002 \penalty3000 \fi + % + % And now, it's time to reuse the body of the original defun: + \expandafter\gobbledefun#1% +} +\def\gobbledefun#1\startdefun{} + +% \printdefunline \deffnheader{text} +% +\def\printdefunline#1#2{% + \begingroup + % call \deffnheader: + #1#2 \endheader + % common ending: + \interlinepenalty = 10000 + \advance\rightskip by 0pt plus 1fil + \endgraf + \nobreak\vskip -\parskip + \penalty 10002 % signal to \startdefun and \dodefunx + % Some of the @defun-type tags do not enable magic parentheses, + % rendering the following check redundant. But we don't optimize. + \checkparencounts + \endgroup +} + +\def\Edefun{\endgraf\medbreak} + +% \makedefun{deffn} creates \deffn, \deffnx and \Edeffn; +% the only thing remainnig is to define \deffnheader. +% +\def\makedefun#1{% + \expandafter\let\csname E#1\endcsname = \Edefun + \edef\temp{\noexpand\domakedefun + \makecsname{#1}\makecsname{#1x}\makecsname{#1header}}% + \temp +} + +% \domakedefun \deffn \deffnx \deffnheader +% +% Define \deffn and \deffnx, without parameters. +% \deffnheader has to be defined explicitly. +% +\def\domakedefun#1#2#3{% + \envdef#1{% + \startdefun + \parseargusing\activeparens{\printdefunline#3}% + }% + \def#2{\dodefunx#1}% + \def#3% +} + +%%% Untyped functions: + +% @deffn category name args +\makedefun{deffn}{\deffngeneral{}} + +% @deffn category class name args +\makedefun{defop}#1 {\defopon{#1\ \putwordon}} + +% \defopon {category on}class name args +\def\defopon#1#2 {\deffngeneral{\putwordon\ \code{#2}}{#1\ \code{#2}} } + +% \deffngeneral {subind}category name args +% +\def\deffngeneral#1#2 #3 #4\endheader{% + % Remember that \dosubind{fn}{foo}{} is equivalent to \doind{fn}{foo}. + \dosubind{fn}{\code{#3}}{#1}% + \defname{#2}{}{#3}\magicamp\defunargs{#4\unskip}% +} + +%%% Typed functions: + +% @deftypefn category type name args +\makedefun{deftypefn}{\deftypefngeneral{}} + +% @deftypeop category class type name args +\makedefun{deftypeop}#1 {\deftypeopon{#1\ \putwordon}} + +% \deftypeopon {category on}class type name args +\def\deftypeopon#1#2 {\deftypefngeneral{\putwordon\ \code{#2}}{#1\ \code{#2}} } + +% \deftypefngeneral {subind}category type name args +% +\def\deftypefngeneral#1#2 #3 #4 #5\endheader{% + \dosubind{fn}{\code{#4}}{#1}% + \defname{#2}{#3}{#4}\defunargs{#5\unskip}% +} + +%%% Typed variables: + +% @deftypevr category type var args +\makedefun{deftypevr}{\deftypecvgeneral{}} + +% @deftypecv category class type var args +\makedefun{deftypecv}#1 {\deftypecvof{#1\ \putwordof}} + +% \deftypecvof {category of}class type var args +\def\deftypecvof#1#2 {\deftypecvgeneral{\putwordof\ \code{#2}}{#1\ \code{#2}} } + +% \deftypecvgeneral {subind}category type var args +% +\def\deftypecvgeneral#1#2 #3 #4 #5\endheader{% + \dosubind{vr}{\code{#4}}{#1}% + \defname{#2}{#3}{#4}\defunargs{#5\unskip}% +} + +%%% Untyped variables: + +% @defvr category var args +\makedefun{defvr}#1 {\deftypevrheader{#1} {} } + +% @defcv category class var args +\makedefun{defcv}#1 {\defcvof{#1\ \putwordof}} + +% \defcvof {category of}class var args +\def\defcvof#1#2 {\deftypecvof{#1}#2 {} } + +%%% Type: +% @deftp category name args +\makedefun{deftp}#1 #2 #3\endheader{% + \doind{tp}{\code{#2}}% + \defname{#1}{}{#2}\defunargs{#3\unskip}% +} + +% Remaining @defun-like shortcuts: +\makedefun{defun}{\deffnheader{\putwordDeffunc} } +\makedefun{defmac}{\deffnheader{\putwordDefmac} } +\makedefun{defspec}{\deffnheader{\putwordDefspec} } +\makedefun{deftypefun}{\deftypefnheader{\putwordDeffunc} } +\makedefun{defvar}{\defvrheader{\putwordDefvar} } +\makedefun{defopt}{\defvrheader{\putwordDefopt} } +\makedefun{deftypevar}{\deftypevrheader{\putwordDefvar} } +\makedefun{defmethod}{\defopon\putwordMethodon} +\makedefun{deftypemethod}{\deftypeopon\putwordMethodon} +\makedefun{defivar}{\defcvof\putwordInstanceVariableof} +\makedefun{deftypeivar}{\deftypecvof\putwordInstanceVariableof} + +% \defname, which formats the name of the @def (not the args). +% #1 is the category, such as "Function". +% #2 is the return type, if any. +% #3 is the function name. +% +% We are followed by (but not passed) the arguments, if any. +% +\def\defname#1#2#3{% + % Get the values of \leftskip and \rightskip as they were outside the @def... + \advance\leftskip by -\defbodyindent + % + % How we'll format the type name. Putting it in brackets helps + % distinguish it from the body text that may end up on the next line + % just below it. + \def\temp{#1}% + \setbox0=\hbox{\kern\deflastargmargin \ifx\temp\empty\else [\rm\temp]\fi} + % + % Figure out line sizes for the paragraph shape. + % The first line needs space for \box0; but if \rightskip is nonzero, + % we need only space for the part of \box0 which exceeds it: + \dimen0=\hsize \advance\dimen0 by -\wd0 \advance\dimen0 by \rightskip + % The continuations: + \dimen2=\hsize \advance\dimen2 by -\defargsindent + % (plain.tex says that \dimen1 should be used only as global.) + \parshape 2 0in \dimen0 \defargsindent \dimen2 + % + % Put the type name to the right margin. + \noindent + \hbox to 0pt{% + \hfil\box0 \kern-\hsize + % \hsize has to be shortened this way: + \kern\leftskip + % Intentionally do not respect \rightskip, since we need the space. + }% + % + % Allow all lines to be underfull without complaint: + \tolerance=10000 \hbadness=10000 + \exdentamount=\defbodyindent + {% + % defun fonts. We use typewriter by default (used to be bold) because: + % . we're printing identifiers, they should be in tt in principle. + % . in languages with many accents, such as Czech or French, it's + % common to leave accents off identifiers. The result looks ok in + % tt, but exceedingly strange in rm. + % . we don't want -- and --- to be treated as ligatures. + % . this still does not fix the ?` and !` ligatures, but so far no + % one has made identifiers using them :). + \df \tt + \def\temp{#2}% return value type + \ifx\temp\empty\else \tclose{\temp} \fi + #3% output function name + }% + {\rm\enskip}% hskip 0.5 em of \tenrm + % + \boldbrax + % arguments will be output next, if any. +} + +% Print arguments in slanted roman (not ttsl), inconsistently with using +% tt for the name. This is because literal text is sometimes needed in +% the argument list (groff manual), and ttsl and tt are not very +% distinguishable. Prevent hyphenation at `-' chars. +% +\def\defunargs#1{% + % use sl by default (not ttsl), + % tt for the names. + \df \sl \hyphenchar\font=0 + % + % On the other hand, if an argument has two dashes (for instance), we + % want a way to get ttsl. Let's try @var for that. + \let\var=\ttslanted + #1% + \sl\hyphenchar\font=45 +} + +% We want ()&[] to print specially on the defun line. +% +\def\activeparens{% + \catcode`\(=\active \catcode`\)=\active + \catcode`\[=\active \catcode`\]=\active + \catcode`\&=\active +} + +% Make control sequences which act like normal parenthesis chars. +\let\lparen = ( \let\rparen = ) + +% Be sure that we always have a definition for `(', etc. For example, +% if the fn name has parens in it, \boldbrax will not be in effect yet, +% so TeX would otherwise complain about undefined control sequence. +{ + \activeparens + \global\let(=\lparen \global\let)=\rparen + \global\let[=\lbrack \global\let]=\rbrack + \global\let& = \& + + \gdef\boldbrax{\let(=\opnr\let)=\clnr\let[=\lbrb\let]=\rbrb} + \gdef\magicamp{\let&=\amprm} +} + +\newcount\parencount + +% If we encounter &foo, then turn on ()-hacking afterwards +\newif\ifampseen +\def\amprm#1 {\ampseentrue{\bf\ }} + +\def\parenfont{% + \ifampseen + % At the first level, print parens in roman, + % otherwise use the default font. + \ifnum \parencount=1 \rm \fi + \else + % The \sf parens (in \boldbrax) actually are a little bolder than + % the contained text. This is especially needed for [ and ] . + \sf + \fi +} +\def\infirstlevel#1{% + \ifampseen + \ifnum\parencount=1 + #1% + \fi + \fi +} +\def\bfafterword#1 {#1 \bf} + +\def\opnr{% + \global\advance\parencount by 1 + {\parenfont(}% + \infirstlevel \bfafterword +} +\def\clnr{% + {\parenfont)}% + \infirstlevel \sl + \global\advance\parencount by -1 +} + +\newcount\brackcount +\def\lbrb{% + \global\advance\brackcount by 1 + {\bf[}% +} +\def\rbrb{% + {\bf]}% + \global\advance\brackcount by -1 +} + +\def\checkparencounts{% + \ifnum\parencount=0 \else \badparencount \fi + \ifnum\brackcount=0 \else \badbrackcount \fi +} +\def\badparencount{% + \errmessage{Unbalanced parentheses in @def}% + \global\parencount=0 +} +\def\badbrackcount{% + \errmessage{Unbalanced square braces in @def}% + \global\brackcount=0 +} + + +\message{macros,} +% @macro. + +% To do this right we need a feature of e-TeX, \scantokens, +% which we arrange to emulate with a temporary file in ordinary TeX. +\ifx\eTeXversion\undefined + \newwrite\macscribble + \def\scantokens#1{% + \toks0={#1}% + \immediate\openout\macscribble=\jobname.tmp + \immediate\write\macscribble{\the\toks0}% + \immediate\closeout\macscribble + \input \jobname.tmp + } +\fi + +\def\scanmacro#1{% + \begingroup + \newlinechar`\^^M + \let\xeatspaces\eatspaces + % Undo catcode changes of \startcontents and \doprintindex + % When called from @insertcopying or (short)caption, we need active + % backslash to get it printed correctly. Previously, we had + % \catcode`\\=\other instead. We'll see whether a problem appears + % with macro expansion. --kasal, 19aug04 + \catcode`\@=0 \catcode`\\=\active \escapechar=`\@ + % ... and \example + \spaceisspace + % + % Append \endinput to make sure that TeX does not see the ending newline. + % + % I've verified that it is necessary both for e-TeX and for ordinary TeX + % --kasal, 29nov03 + \scantokens{#1\endinput}% + \endgroup +} + +\def\scanexp#1{% + \edef\temp{\noexpand\scanmacro{#1}}% + \temp +} + +\newcount\paramno % Count of parameters +\newtoks\macname % Macro name +\newif\ifrecursive % Is it recursive? +\def\macrolist{} % List of all defined macros in the form + % \do\macro1\do\macro2... + +% Utility routines. +% This does \let #1 = #2, with \csnames; that is, +% \let \csname#1\endcsname = \csname#2\endcsname +% (except of course we have to play expansion games). +% +\def\cslet#1#2{% + \expandafter\let + \csname#1\expandafter\endcsname + \csname#2\endcsname +} + +% Trim leading and trailing spaces off a string. +% Concepts from aro-bend problem 15 (see CTAN). +{\catcode`\@=11 +\gdef\eatspaces #1{\expandafter\trim@\expandafter{#1 }} +\gdef\trim@ #1{\trim@@ @#1 @ #1 @ @@} +\gdef\trim@@ #1@ #2@ #3@@{\trim@@@\empty #2 @} +\def\unbrace#1{#1} +\unbrace{\gdef\trim@@@ #1 } #2@{#1} +} + +% Trim a single trailing ^^M off a string. +{\catcode`\^^M=\other \catcode`\Q=3% +\gdef\eatcr #1{\eatcra #1Q^^MQ}% +\gdef\eatcra#1^^MQ{\eatcrb#1Q}% +\gdef\eatcrb#1Q#2Q{#1}% +} + +% Macro bodies are absorbed as an argument in a context where +% all characters are catcode 10, 11 or 12, except \ which is active +% (as in normal texinfo). It is necessary to change the definition of \. + +% It's necessary to have hard CRs when the macro is executed. This is +% done by making ^^M (\endlinechar) catcode 12 when reading the macro +% body, and then making it the \newlinechar in \scanmacro. + +\def\scanctxt{% + \catcode`\"=\other + \catcode`\+=\other + \catcode`\<=\other + \catcode`\>=\other + \catcode`\@=\other + \catcode`\^=\other + \catcode`\_=\other + \catcode`\|=\other + \catcode`\~=\other +} + +\def\scanargctxt{% + \scanctxt + \catcode`\\=\other + \catcode`\^^M=\other +} + +\def\macrobodyctxt{% + \scanctxt + \catcode`\{=\other + \catcode`\}=\other + \catcode`\^^M=\other + \usembodybackslash +} + +\def\macroargctxt{% + \scanctxt + \catcode`\\=\other +} + +% \mbodybackslash is the definition of \ in @macro bodies. +% It maps \foo\ => \csname macarg.foo\endcsname => #N +% where N is the macro parameter number. +% We define \csname macarg.\endcsname to be \realbackslash, so +% \\ in macro replacement text gets you a backslash. + +{\catcode`@=0 @catcode`@\=@active + @gdef@usembodybackslash{@let\=@mbodybackslash} + @gdef@mbodybackslash#1\{@csname macarg.#1@endcsname} +} +\expandafter\def\csname macarg.\endcsname{\realbackslash} + +\def\macro{\recursivefalse\parsearg\macroxxx} +\def\rmacro{\recursivetrue\parsearg\macroxxx} + +\def\macroxxx#1{% + \getargs{#1}% now \macname is the macname and \argl the arglist + \ifx\argl\empty % no arguments + \paramno=0% + \else + \expandafter\parsemargdef \argl;% + \fi + \if1\csname ismacro.\the\macname\endcsname + \message{Warning: redefining \the\macname}% + \else + \expandafter\ifx\csname \the\macname\endcsname \relax + \else \errmessage{Macro name \the\macname\space already defined}\fi + \global\cslet{macsave.\the\macname}{\the\macname}% + \global\expandafter\let\csname ismacro.\the\macname\endcsname=1% + % Add the macroname to \macrolist + \toks0 = \expandafter{\macrolist\do}% + \xdef\macrolist{\the\toks0 + \expandafter\noexpand\csname\the\macname\endcsname}% + \fi + \begingroup \macrobodyctxt + \ifrecursive \expandafter\parsermacbody + \else \expandafter\parsemacbody + \fi} + +\parseargdef\unmacro{% + \if1\csname ismacro.#1\endcsname + \global\cslet{#1}{macsave.#1}% + \global\expandafter\let \csname ismacro.#1\endcsname=0% + % Remove the macro name from \macrolist: + \begingroup + \expandafter\let\csname#1\endcsname \relax + \let\do\unmacrodo + \xdef\macrolist{\macrolist}% + \endgroup + \else + \errmessage{Macro #1 not defined}% + \fi +} + +% Called by \do from \dounmacro on each macro. The idea is to omit any +% macro definitions that have been changed to \relax. +% +\def\unmacrodo#1{% + \ifx#1\relax + % remove this + \else + \noexpand\do \noexpand #1% + \fi +} + +% This makes use of the obscure feature that if the last token of a +% <parameter list> is #, then the preceding argument is delimited by +% an opening brace, and that opening brace is not consumed. +\def\getargs#1{\getargsxxx#1{}} +\def\getargsxxx#1#{\getmacname #1 \relax\getmacargs} +\def\getmacname #1 #2\relax{\macname={#1}} +\def\getmacargs#1{\def\argl{#1}} + +% Parse the optional {params} list. Set up \paramno and \paramlist +% so \defmacro knows what to do. Define \macarg.blah for each blah +% in the params list, to be ##N where N is the position in that list. +% That gets used by \mbodybackslash (above). + +% We need to get `macro parameter char #' into several definitions. +% The technique used is stolen from LaTeX: let \hash be something +% unexpandable, insert that wherever you need a #, and then redefine +% it to # just before using the token list produced. +% +% The same technique is used to protect \eatspaces till just before +% the macro is used. + +\def\parsemargdef#1;{\paramno=0\def\paramlist{}% + \let\hash\relax\let\xeatspaces\relax\parsemargdefxxx#1,;,} +\def\parsemargdefxxx#1,{% + \if#1;\let\next=\relax + \else \let\next=\parsemargdefxxx + \advance\paramno by 1% + \expandafter\edef\csname macarg.\eatspaces{#1}\endcsname + {\xeatspaces{\hash\the\paramno}}% + \edef\paramlist{\paramlist\hash\the\paramno,}% + \fi\next} + +% These two commands read recursive and nonrecursive macro bodies. +% (They're different since rec and nonrec macros end differently.) + +\long\def\parsemacbody#1@end macro% +{\xdef\temp{\eatcr{#1}}\endgroup\defmacro}% +\long\def\parsermacbody#1@end rmacro% +{\xdef\temp{\eatcr{#1}}\endgroup\defmacro}% + +% This defines the macro itself. There are six cases: recursive and +% nonrecursive macros of zero, one, and many arguments. +% Much magic with \expandafter here. +% \xdef is used so that macro definitions will survive the file +% they're defined in; @include reads the file inside a group. +\def\defmacro{% + \let\hash=##% convert placeholders to macro parameter chars + \ifrecursive + \ifcase\paramno + % 0 + \expandafter\xdef\csname\the\macname\endcsname{% + \noexpand\scanmacro{\temp}}% + \or % 1 + \expandafter\xdef\csname\the\macname\endcsname{% + \bgroup\noexpand\macroargctxt + \noexpand\braceorline + \expandafter\noexpand\csname\the\macname xxx\endcsname}% + \expandafter\xdef\csname\the\macname xxx\endcsname##1{% + \egroup\noexpand\scanmacro{\temp}}% + \else % many + \expandafter\xdef\csname\the\macname\endcsname{% + \bgroup\noexpand\macroargctxt + \noexpand\csname\the\macname xx\endcsname}% + \expandafter\xdef\csname\the\macname xx\endcsname##1{% + \expandafter\noexpand\csname\the\macname xxx\endcsname ##1,}% + \expandafter\expandafter + \expandafter\xdef + \expandafter\expandafter + \csname\the\macname xxx\endcsname + \paramlist{\egroup\noexpand\scanmacro{\temp}}% + \fi + \else + \ifcase\paramno + % 0 + \expandafter\xdef\csname\the\macname\endcsname{% + \noexpand\norecurse{\the\macname}% + \noexpand\scanmacro{\temp}\egroup}% + \or % 1 + \expandafter\xdef\csname\the\macname\endcsname{% + \bgroup\noexpand\macroargctxt + \noexpand\braceorline + \expandafter\noexpand\csname\the\macname xxx\endcsname}% + \expandafter\xdef\csname\the\macname xxx\endcsname##1{% + \egroup + \noexpand\norecurse{\the\macname}% + \noexpand\scanmacro{\temp}\egroup}% + \else % many + \expandafter\xdef\csname\the\macname\endcsname{% + \bgroup\noexpand\macroargctxt + \expandafter\noexpand\csname\the\macname xx\endcsname}% + \expandafter\xdef\csname\the\macname xx\endcsname##1{% + \expandafter\noexpand\csname\the\macname xxx\endcsname ##1,}% + \expandafter\expandafter + \expandafter\xdef + \expandafter\expandafter + \csname\the\macname xxx\endcsname + \paramlist{% + \egroup + \noexpand\norecurse{\the\macname}% + \noexpand\scanmacro{\temp}\egroup}% + \fi + \fi} + +\def\norecurse#1{\bgroup\cslet{#1}{macsave.#1}} + +% \braceorline decides whether the next nonwhitespace character is a +% {. If so it reads up to the closing }, if not, it reads the whole +% line. Whatever was read is then fed to the next control sequence +% as an argument (by \parsebrace or \parsearg) +\def\braceorline#1{\let\next=#1\futurelet\nchar\braceorlinexxx} +\def\braceorlinexxx{% + \ifx\nchar\bgroup\else + \expandafter\parsearg + \fi \next} + +% We want to disable all macros during \shipout so that they are not +% expanded by \write. +\def\turnoffmacros{\begingroup \def\do##1{\let\noexpand##1=\relax}% + \edef\next{\macrolist}\expandafter\endgroup\next} + +% For \indexnofonts, we need to get rid of all macros, leaving only the +% arguments (if present). Of course this is not nearly correct, but it +% is the best we can do for now. makeinfo does not expand macros in the +% argument to @deffn, which ends up writing an index entry, and texindex +% isn't prepared for an index sort entry that starts with \. +% +% Since macro invocations are followed by braces, we can just redefine them +% to take a single TeX argument. The case of a macro invocation that +% goes to end-of-line is not handled. +% +\def\emptyusermacros{\begingroup + \def\do##1{\let\noexpand##1=\noexpand\asis}% + \edef\next{\macrolist}\expandafter\endgroup\next} + + +% @alias. +% We need some trickery to remove the optional spaces around the equal +% sign. Just make them active and then expand them all to nothing. +\def\alias{\parseargusing\obeyspaces\aliasxxx} +\def\aliasxxx #1{\aliasyyy#1\relax} +\def\aliasyyy #1=#2\relax{% + {% + \expandafter\let\obeyedspace=\empty + \xdef\next{\global\let\makecsname{#1}=\makecsname{#2}}% + }% + \next +} + + +\message{cross references,} + +\newwrite\auxfile + +\newif\ifhavexrefs % True if xref values are known. +\newif\ifwarnedxrefs % True if we warned once that they aren't known. + +% @inforef is relatively simple. +\def\inforef #1{\inforefzzz #1,,,,**} +\def\inforefzzz #1,#2,#3,#4**{\putwordSee{} \putwordInfo{} \putwordfile{} \file{\ignorespaces #3{}}, + node \samp{\ignorespaces#1{}}} + +% @node's only job in TeX is to define \lastnode, which is used in +% cross-references. The @node line might or might not have commas, and +% might or might not have spaces before the first comma, like: +% @node foo , bar , ... +% We don't want such trailing spaces in the node name. +% +\parseargdef\node{\checkenv{}\donode #1 ,\finishnodeparse} +% +% also remove a trailing comma, in case of something like this: +% @node Help-Cross, , , Cross-refs +\def\donode#1 ,#2\finishnodeparse{\dodonode #1,\finishnodeparse} +\def\dodonode#1,#2\finishnodeparse{\gdef\lastnode{#1}} + +\let\nwnode=\node +\let\lastnode=\empty + +% Write a cross-reference definition for the current node. #1 is the +% type (Ynumbered, Yappendix, Ynothing). +% +\def\donoderef#1{% + \ifx\lastnode\empty\else + \setref{\lastnode}{#1}% + \global\let\lastnode=\empty + \fi +} + +% @anchor{NAME} -- define xref target at arbitrary point. +% +\newcount\savesfregister +% +\def\savesf{\relax \ifhmode \savesfregister=\spacefactor \fi} +\def\restoresf{\relax \ifhmode \spacefactor=\savesfregister \fi} +\def\anchor#1{\savesf \setref{#1}{Ynothing}\restoresf \ignorespaces} + +% \setref{NAME}{SNT} defines a cross-reference point NAME (a node or an +% anchor), which consists of three parts: +% 1) NAME-title - the current sectioning name taken from \thissection, +% or the anchor name. +% 2) NAME-snt - section number and type, passed as the SNT arg, or +% empty for anchors. +% 3) NAME-pg - the page number. +% +% This is called from \donoderef, \anchor, and \dofloat. In the case of +% floats, there is an additional part, which is not written here: +% 4) NAME-lof - the text as it should appear in a @listoffloats. +% +\def\setref#1#2{% + \pdfmkdest{#1}% + \iflinks + {% + \atdummies % preserve commands, but don't expand them + \turnoffactive + \edef\writexrdef##1##2{% + \write\auxfile{@xrdef{#1-% #1 of \setref, expanded by the \edef + ##1}{##2}}% these are parameters of \writexrdef + }% + \toks0 = \expandafter{\thissection}% + \immediate \writexrdef{title}{\the\toks0 }% + \immediate \writexrdef{snt}{\csname #2\endcsname}% \Ynumbered etc. + \writexrdef{pg}{\folio}% will be written later, during \shipout + }% + \fi +} + +% @xref, @pxref, and @ref generate cross-references. For \xrefX, #1 is +% the node name, #2 the name of the Info cross-reference, #3 the printed +% node name, #4 the name of the Info file, #5 the name of the printed +% manual. All but the node name can be omitted. +% +\def\pxref#1{\putwordsee{} \xrefX[#1,,,,,,,]} +\def\xref#1{\putwordSee{} \xrefX[#1,,,,,,,]} +\def\ref#1{\xrefX[#1,,,,,,,]} +\def\xrefX[#1,#2,#3,#4,#5,#6]{\begingroup + \unsepspaces + \def\printedmanual{\ignorespaces #5}% + \def\printedrefname{\ignorespaces #3}% + \setbox1=\hbox{\printedmanual\unskip}% + \setbox0=\hbox{\printedrefname\unskip}% + \ifdim \wd0 = 0pt + % No printed node name was explicitly given. + \expandafter\ifx\csname SETxref-automatic-section-title\endcsname\relax + % Use the node name inside the square brackets. + \def\printedrefname{\ignorespaces #1}% + \else + % Use the actual chapter/section title appear inside + % the square brackets. Use the real section title if we have it. + \ifdim \wd1 > 0pt + % It is in another manual, so we don't have it. + \def\printedrefname{\ignorespaces #1}% + \else + \ifhavexrefs + % We know the real title if we have the xref values. + \def\printedrefname{\refx{#1-title}{}}% + \else + % Otherwise just copy the Info node name. + \def\printedrefname{\ignorespaces #1}% + \fi% + \fi + \fi + \fi + % + % Make link in pdf output. + \ifpdf + \leavevmode + \getfilename{#4}% + {\turnoffactive + % See comments at \activebackslashdouble. + {\activebackslashdouble \xdef\pdfxrefdest{#1}% + \backslashparens\pdfxrefdest}% + % + \ifnum\filenamelength>0 + \startlink attr{/Border [0 0 0]}% + goto file{\the\filename.pdf} name{\pdfxrefdest}% + \else + \startlink attr{/Border [0 0 0]}% + goto name{\pdfmkpgn{\pdfxrefdest}}% + \fi + }% + \linkcolor + \fi + % + % Float references are printed completely differently: "Figure 1.2" + % instead of "[somenode], p.3". We distinguish them by the + % LABEL-title being set to a magic string. + {% + % Have to otherify everything special to allow the \csname to + % include an _ in the xref name, etc. + \indexnofonts + \turnoffactive + \expandafter\global\expandafter\let\expandafter\Xthisreftitle + \csname XR#1-title\endcsname + }% + \iffloat\Xthisreftitle + % If the user specified the print name (third arg) to the ref, + % print it instead of our usual "Figure 1.2". + \ifdim\wd0 = 0pt + \refx{#1-snt}% + \else + \printedrefname + \fi + % + % if the user also gave the printed manual name (fifth arg), append + % "in MANUALNAME". + \ifdim \wd1 > 0pt + \space \putwordin{} \cite{\printedmanual}% + \fi + \else + % node/anchor (non-float) references. + % + % If we use \unhbox0 and \unhbox1 to print the node names, TeX does not + % insert empty discretionaries after hyphens, which means that it will + % not find a line break at a hyphen in a node names. Since some manuals + % are best written with fairly long node names, containing hyphens, this + % is a loss. Therefore, we give the text of the node name again, so it + % is as if TeX is seeing it for the first time. + \ifdim \wd1 > 0pt + \putwordsection{} ``\printedrefname'' \putwordin{} \cite{\printedmanual}% + \else + % _ (for example) has to be the character _ for the purposes of the + % control sequence corresponding to the node, but it has to expand + % into the usual \leavevmode...\vrule stuff for purposes of + % printing. So we \turnoffactive for the \refx-snt, back on for the + % printing, back off for the \refx-pg. + {\turnoffactive + % Only output a following space if the -snt ref is nonempty; for + % @unnumbered and @anchor, it won't be. + \setbox2 = \hbox{\ignorespaces \refx{#1-snt}{}}% + \ifdim \wd2 > 0pt \refx{#1-snt}\space\fi + }% + % output the `[mynode]' via a macro so it can be overridden. + \xrefprintnodename\printedrefname + % + % But we always want a comma and a space: + ,\space + % + % output the `page 3'. + \turnoffactive \putwordpage\tie\refx{#1-pg}{}% + \fi + \fi + \endlink +\endgroup} + +% This macro is called from \xrefX for the `[nodename]' part of xref +% output. It's a separate macro only so it can be changed more easily, +% since square brackets don't work well in some documents. Particularly +% one that Bob is working on :). +% +\def\xrefprintnodename#1{[#1]} + +% Things referred to by \setref. +% +\def\Ynothing{} +\def\Yomitfromtoc{} +\def\Ynumbered{% + \ifnum\secno=0 + \putwordChapter@tie \the\chapno + \else \ifnum\subsecno=0 + \putwordSection@tie \the\chapno.\the\secno + \else \ifnum\subsubsecno=0 + \putwordSection@tie \the\chapno.\the\secno.\the\subsecno + \else + \putwordSection@tie \the\chapno.\the\secno.\the\subsecno.\the\subsubsecno + \fi\fi\fi +} +\def\Yappendix{% + \ifnum\secno=0 + \putwordAppendix@tie @char\the\appendixno{}% + \else \ifnum\subsecno=0 + \putwordSection@tie @char\the\appendixno.\the\secno + \else \ifnum\subsubsecno=0 + \putwordSection@tie @char\the\appendixno.\the\secno.\the\subsecno + \else + \putwordSection@tie + @char\the\appendixno.\the\secno.\the\subsecno.\the\subsubsecno + \fi\fi\fi +} + +% Define \refx{NAME}{SUFFIX} to reference a cross-reference string named NAME. +% If its value is nonempty, SUFFIX is output afterward. +% +\def\refx#1#2{% + {% + \indexnofonts + \otherbackslash + \expandafter\global\expandafter\let\expandafter\thisrefX + \csname XR#1\endcsname + }% + \ifx\thisrefX\relax + % If not defined, say something at least. + \angleleft un\-de\-fined\angleright + \iflinks + \ifhavexrefs + \message{\linenumber Undefined cross reference `#1'.}% + \else + \ifwarnedxrefs\else + \global\warnedxrefstrue + \message{Cross reference values unknown; you must run TeX again.}% + \fi + \fi + \fi + \else + % It's defined, so just use it. + \thisrefX + \fi + #2% Output the suffix in any case. +} + +% This is the macro invoked by entries in the aux file. Usually it's +% just a \def (we prepend XR to the control sequence name to avoid +% collisions). But if this is a float type, we have more work to do. +% +\def\xrdef#1#2{% + \expandafter\gdef\csname XR#1\endcsname{#2}% remember this xref value. + % + % Was that xref control sequence that we just defined for a float? + \expandafter\iffloat\csname XR#1\endcsname + % it was a float, and we have the (safe) float type in \iffloattype. + \expandafter\let\expandafter\floatlist + \csname floatlist\iffloattype\endcsname + % + % Is this the first time we've seen this float type? + \expandafter\ifx\floatlist\relax + \toks0 = {\do}% yes, so just \do + \else + % had it before, so preserve previous elements in list. + \toks0 = \expandafter{\floatlist\do}% + \fi + % + % Remember this xref in the control sequence \floatlistFLOATTYPE, + % for later use in \listoffloats. + \expandafter\xdef\csname floatlist\iffloattype\endcsname{\the\toks0{#1}}% + \fi +} + +% Read the last existing aux file, if any. No error if none exists. +% +\def\tryauxfile{% + \openin 1 \jobname.aux + \ifeof 1 \else + \readdatafile{aux}% + \global\havexrefstrue + \fi + \closein 1 +} + +\def\setupdatafile{% + \catcode`\^^@=\other + \catcode`\^^A=\other + \catcode`\^^B=\other + \catcode`\^^C=\other + \catcode`\^^D=\other + \catcode`\^^E=\other + \catcode`\^^F=\other + \catcode`\^^G=\other + \catcode`\^^H=\other + \catcode`\^^K=\other + \catcode`\^^L=\other + \catcode`\^^N=\other + \catcode`\^^P=\other + \catcode`\^^Q=\other + \catcode`\^^R=\other + \catcode`\^^S=\other + \catcode`\^^T=\other + \catcode`\^^U=\other + \catcode`\^^V=\other + \catcode`\^^W=\other + \catcode`\^^X=\other + \catcode`\^^Z=\other + \catcode`\^^[=\other + \catcode`\^^\=\other + \catcode`\^^]=\other + \catcode`\^^^=\other + \catcode`\^^_=\other + % It was suggested to set the catcode of ^ to 7, which would allow ^^e4 etc. + % in xref tags, i.e., node names. But since ^^e4 notation isn't + % supported in the main text, it doesn't seem desirable. Furthermore, + % that is not enough: for node names that actually contain a ^ + % character, we would end up writing a line like this: 'xrdef {'hat + % b-title}{'hat b} and \xrdef does a \csname...\endcsname on the first + % argument, and \hat is not an expandable control sequence. It could + % all be worked out, but why? Either we support ^^ or we don't. + % + % The other change necessary for this was to define \auxhat: + % \def\auxhat{\def^{'hat }}% extra space so ok if followed by letter + % and then to call \auxhat in \setq. + % + \catcode`\^=\other + % + % Special characters. Should be turned off anyway, but... + \catcode`\~=\other + \catcode`\[=\other + \catcode`\]=\other + \catcode`\"=\other + \catcode`\_=\other + \catcode`\|=\other + \catcode`\<=\other + \catcode`\>=\other + \catcode`\$=\other + \catcode`\#=\other + \catcode`\&=\other + \catcode`\%=\other + \catcode`+=\other % avoid \+ for paranoia even though we've turned it off + % + % This is to support \ in node names and titles, since the \ + % characters end up in a \csname. It's easier than + % leaving it active and making its active definition an actual \ + % character. What I don't understand is why it works in the *value* + % of the xrdef. Seems like it should be a catcode12 \, and that + % should not typeset properly. But it works, so I'm moving on for + % now. --karl, 15jan04. + \catcode`\\=\other + % + % Make the characters 128-255 be printing characters. + {% + \count1=128 + \def\loop{% + \catcode\count1=\other + \advance\count1 by 1 + \ifnum \count1<256 \loop \fi + }% + }% + % + % @ is our escape character in .aux files, and we need braces. + \catcode`\{=1 + \catcode`\}=2 + \catcode`\@=0 +} + +\def\readdatafile#1{% +\begingroup + \setupdatafile + \input\jobname.#1 +\endgroup} + +\message{insertions,} +% including footnotes. + +\newcount \footnoteno + +% The trailing space in the following definition for supereject is +% vital for proper filling; pages come out unaligned when you do a +% pagealignmacro call if that space before the closing brace is +% removed. (Generally, numeric constants should always be followed by a +% space to prevent strange expansion errors.) +\def\supereject{\par\penalty -20000\footnoteno =0 } + +% @footnotestyle is meaningful for info output only. +\let\footnotestyle=\comment + +{\catcode `\@=11 +% +% Auto-number footnotes. Otherwise like plain. +\gdef\footnote{% + \let\indent=\ptexindent + \let\noindent=\ptexnoindent + \global\advance\footnoteno by \@ne + \edef\thisfootno{$^{\the\footnoteno}$}% + % + % In case the footnote comes at the end of a sentence, preserve the + % extra spacing after we do the footnote number. + \let\@sf\empty + \ifhmode\edef\@sf{\spacefactor\the\spacefactor}\ptexslash\fi + % + % Remove inadvertent blank space before typesetting the footnote number. + \unskip + \thisfootno\@sf + \dofootnote +}% + +% Don't bother with the trickery in plain.tex to not require the +% footnote text as a parameter. Our footnotes don't need to be so general. +% +% Oh yes, they do; otherwise, @ifset (and anything else that uses +% \parseargline) fails inside footnotes because the tokens are fixed when +% the footnote is read. --karl, 16nov96. +% +\gdef\dofootnote{% + \insert\footins\bgroup + % We want to typeset this text as a normal paragraph, even if the + % footnote reference occurs in (for example) a display environment. + % So reset some parameters. + \hsize=\pagewidth + \interlinepenalty\interfootnotelinepenalty + \splittopskip\ht\strutbox % top baseline for broken footnotes + \splitmaxdepth\dp\strutbox + \floatingpenalty\@MM + \leftskip\z@skip + \rightskip\z@skip + \spaceskip\z@skip + \xspaceskip\z@skip + \parindent\defaultparindent + % + \smallfonts \rm + % + % Because we use hanging indentation in footnotes, a @noindent appears + % to exdent this text, so make it be a no-op. makeinfo does not use + % hanging indentation so @noindent can still be needed within footnote + % text after an @example or the like (not that this is good style). + \let\noindent = \relax + % + % Hang the footnote text off the number. Use \everypar in case the + % footnote extends for more than one paragraph. + \everypar = {\hang}% + \textindent{\thisfootno}% + % + % Don't crash into the line above the footnote text. Since this + % expands into a box, it must come within the paragraph, lest it + % provide a place where TeX can split the footnote. + \footstrut + \futurelet\next\fo@t +} +}%end \catcode `\@=11 + +% In case a @footnote appears in a vbox, save the footnote text and create +% the real \insert just after the vbox finished. Otherwise, the insertion +% would be lost. +% Similarily, if a @footnote appears inside an alignment, save the footnote +% text to a box and make the \insert when a row of the table is finished. +% And the same can be done for other insert classes. --kasal, 16nov03. + +% Replace the \insert primitive by a cheating macro. +% Deeper inside, just make sure that the saved insertions are not spilled +% out prematurely. +% +\def\startsavinginserts{% + \ifx \insert\ptexinsert + \let\insert\saveinsert + \else + \let\checkinserts\relax + \fi +} + +% This \insert replacement works for both \insert\footins{foo} and +% \insert\footins\bgroup foo\egroup, but it doesn't work for \insert27{foo}. +% +\def\saveinsert#1{% + \edef\next{\noexpand\savetobox \makeSAVEname#1}% + \afterassignment\next + % swallow the left brace + \let\temp = +} +\def\makeSAVEname#1{\makecsname{SAVE\expandafter\gobble\string#1}} +\def\savetobox#1{\global\setbox#1 = \vbox\bgroup \unvbox#1} + +\def\checksaveins#1{\ifvoid#1\else \placesaveins#1\fi} + +\def\placesaveins#1{% + \ptexinsert \csname\expandafter\gobblesave\string#1\endcsname + {\box#1}% +} + +% eat @SAVE -- beware, all of them have catcode \other: +{ + \def\dospecials{\do S\do A\do V\do E} \uncatcodespecials % ;-) + \gdef\gobblesave @SAVE{} +} + +% initialization: +\def\newsaveins #1{% + \edef\next{\noexpand\newsaveinsX \makeSAVEname#1}% + \next +} +\def\newsaveinsX #1{% + \csname newbox\endcsname #1% + \expandafter\def\expandafter\checkinserts\expandafter{\checkinserts + \checksaveins #1}% +} + +% initialize: +\let\checkinserts\empty +\newsaveins\footins +\newsaveins\margin + + +% @image. We use the macros from epsf.tex to support this. +% If epsf.tex is not installed and @image is used, we complain. +% +% Check for and read epsf.tex up front. If we read it only at @image +% time, we might be inside a group, and then its definitions would get +% undone and the next image would fail. +\openin 1 = epsf.tex +\ifeof 1 \else + % Do not bother showing banner with epsf.tex v2.7k (available in + % doc/epsf.tex and on ctan). + \def\epsfannounce{\toks0 = }% + \input epsf.tex +\fi +\closein 1 +% +% We will only complain once about lack of epsf.tex. +\newif\ifwarnednoepsf +\newhelp\noepsfhelp{epsf.tex must be installed for images to + work. It is also included in the Texinfo distribution, or you can get + it from ftp://tug.org/tex/epsf.tex.} +% +\def\image#1{% + \ifx\epsfbox\undefined + \ifwarnednoepsf \else + \errhelp = \noepsfhelp + \errmessage{epsf.tex not found, images will be ignored}% + \global\warnednoepsftrue + \fi + \else + \imagexxx #1,,,,,\finish + \fi +} +% +% Arguments to @image: +% #1 is (mandatory) image filename; we tack on .eps extension. +% #2 is (optional) width, #3 is (optional) height. +% #4 is (ignored optional) html alt text. +% #5 is (ignored optional) extension. +% #6 is just the usual extra ignored arg for parsing this stuff. +\newif\ifimagevmode +\def\imagexxx#1,#2,#3,#4,#5,#6\finish{\begingroup + \catcode`\^^M = 5 % in case we're inside an example + \normalturnoffactive % allow _ et al. in names + % If the image is by itself, center it. + \ifvmode + \imagevmodetrue + \nobreak\bigskip + % Usually we'll have text after the image which will insert + % \parskip glue, so insert it here too to equalize the space + % above and below. + \nobreak\vskip\parskip + \nobreak + \line\bgroup\hss + \fi + % + % Output the image. + \ifpdf + \dopdfimage{#1}{#2}{#3}% + \else + % \epsfbox itself resets \epsf?size at each figure. + \setbox0 = \hbox{\ignorespaces #2}\ifdim\wd0 > 0pt \epsfxsize=#2\relax \fi + \setbox0 = \hbox{\ignorespaces #3}\ifdim\wd0 > 0pt \epsfysize=#3\relax \fi + \epsfbox{#1.eps}% + \fi + % + \ifimagevmode \hss \egroup \bigbreak \fi % space after the image +\endgroup} + + +% @float FLOATTYPE,LABEL,LOC ... @end float for displayed figures, tables, +% etc. We don't actually implement floating yet, we always include the +% float "here". But it seemed the best name for the future. +% +\envparseargdef\float{\eatcommaspace\eatcommaspace\dofloat#1, , ,\finish} + +% There may be a space before second and/or third parameter; delete it. +\def\eatcommaspace#1, {#1,} + +% #1 is the optional FLOATTYPE, the text label for this float, typically +% "Figure", "Table", "Example", etc. Can't contain commas. If omitted, +% this float will not be numbered and cannot be referred to. +% +% #2 is the optional xref label. Also must be present for the float to +% be referable. +% +% #3 is the optional positioning argument; for now, it is ignored. It +% will somehow specify the positions allowed to float to (here, top, bottom). +% +% We keep a separate counter for each FLOATTYPE, which we reset at each +% chapter-level command. +\let\resetallfloatnos=\empty +% +\def\dofloat#1,#2,#3,#4\finish{% + \let\thiscaption=\empty + \let\thisshortcaption=\empty + % + % don't lose footnotes inside @float. + % + % BEWARE: when the floats start float, we have to issue warning whenever an + % insert appears inside a float which could possibly float. --kasal, 26may04 + % + \startsavinginserts + % + % We can't be used inside a paragraph. + \par + % + \vtop\bgroup + \def\floattype{#1}% + \def\floatlabel{#2}% + \def\floatloc{#3}% we do nothing with this yet. + % + \ifx\floattype\empty + \let\safefloattype=\empty + \else + {% + % the floattype might have accents or other special characters, + % but we need to use it in a control sequence name. + \indexnofonts + \turnoffactive + \xdef\safefloattype{\floattype}% + }% + \fi + % + % If label is given but no type, we handle that as the empty type. + \ifx\floatlabel\empty \else + % We want each FLOATTYPE to be numbered separately (Figure 1, + % Table 1, Figure 2, ...). (And if no label, no number.) + % + \expandafter\getfloatno\csname\safefloattype floatno\endcsname + \global\advance\floatno by 1 + % + {% + % This magic value for \thissection is output by \setref as the + % XREFLABEL-title value. \xrefX uses it to distinguish float + % labels (which have a completely different output format) from + % node and anchor labels. And \xrdef uses it to construct the + % lists of floats. + % + \edef\thissection{\floatmagic=\safefloattype}% + \setref{\floatlabel}{Yfloat}% + }% + \fi + % + % start with \parskip glue, I guess. + \vskip\parskip + % + % Don't suppress indentation if a float happens to start a section. + \restorefirstparagraphindent +} + +% we have these possibilities: +% @float Foo,lbl & @caption{Cap}: Foo 1.1: Cap +% @float Foo,lbl & no caption: Foo 1.1 +% @float Foo & @caption{Cap}: Foo: Cap +% @float Foo & no caption: Foo +% @float ,lbl & Caption{Cap}: 1.1: Cap +% @float ,lbl & no caption: 1.1 +% @float & @caption{Cap}: Cap +% @float & no caption: +% +\def\Efloat{% + \let\floatident = \empty + % + % In all cases, if we have a float type, it comes first. + \ifx\floattype\empty \else \def\floatident{\floattype}\fi + % + % If we have an xref label, the number comes next. + \ifx\floatlabel\empty \else + \ifx\floattype\empty \else % if also had float type, need tie first. + \appendtomacro\floatident{\tie}% + \fi + % the number. + \appendtomacro\floatident{\chaplevelprefix\the\floatno}% + \fi + % + % Start the printed caption with what we've constructed in + % \floatident, but keep it separate; we need \floatident again. + \let\captionline = \floatident + % + \ifx\thiscaption\empty \else + \ifx\floatident\empty \else + \appendtomacro\captionline{: }% had ident, so need a colon between + \fi + % + % caption text. + \appendtomacro\captionline{\scanexp\thiscaption}% + \fi + % + % If we have anything to print, print it, with space before. + % Eventually this needs to become an \insert. + \ifx\captionline\empty \else + \vskip.5\parskip + \captionline + % + % Space below caption. + \vskip\parskip + \fi + % + % If have an xref label, write the list of floats info. Do this + % after the caption, to avoid chance of it being a breakpoint. + \ifx\floatlabel\empty \else + % Write the text that goes in the lof to the aux file as + % \floatlabel-lof. Besides \floatident, we include the short + % caption if specified, else the full caption if specified, else nothing. + {% + \atdummies \turnoffactive + % since we read the caption text in the macro world, where ^^M + % is turned into a normal character, we have to scan it back, so + % we don't write the literal three characters "^^M" into the aux file. + \scanexp{% + \xdef\noexpand\gtemp{% + \ifx\thisshortcaption\empty + \thiscaption + \else + \thisshortcaption + \fi + }% + }% + \immediate\write\auxfile{@xrdef{\floatlabel-lof}{\floatident + \ifx\gtemp\empty \else : \gtemp \fi}}% + }% + \fi + \egroup % end of \vtop + % + % place the captured inserts + % + % BEWARE: when the floats start float, we have to issue warning whenever an + % insert appears inside a float which could possibly float. --kasal, 26may04 + % + \checkinserts +} + +% Append the tokens #2 to the definition of macro #1, not expanding either. +% +\def\appendtomacro#1#2{% + \expandafter\def\expandafter#1\expandafter{#1#2}% +} + +% @caption, @shortcaption +% +\def\caption{\docaption\thiscaption} +\def\shortcaption{\docaption\thisshortcaption} +\def\docaption{\checkenv\float \bgroup\scanargctxt\defcaption} +\def\defcaption#1#2{\egroup \def#1{#2}} + +% The parameter is the control sequence identifying the counter we are +% going to use. Create it if it doesn't exist and assign it to \floatno. +\def\getfloatno#1{% + \ifx#1\relax + % Haven't seen this figure type before. + \csname newcount\endcsname #1% + % + % Remember to reset this floatno at the next chap. + \expandafter\gdef\expandafter\resetallfloatnos + \expandafter{\resetallfloatnos #1=0 }% + \fi + \let\floatno#1% +} + +% \setref calls this to get the XREFLABEL-snt value. We want an @xref +% to the FLOATLABEL to expand to "Figure 3.1". We call \setref when we +% first read the @float command. +% +\def\Yfloat{\floattype@tie \chaplevelprefix\the\floatno}% + +% Magic string used for the XREFLABEL-title value, so \xrefX can +% distinguish floats from other xref types. +\def\floatmagic{!!float!!} + +% #1 is the control sequence we are passed; we expand into a conditional +% which is true if #1 represents a float ref. That is, the magic +% \thissection value which we \setref above. +% +\def\iffloat#1{\expandafter\doiffloat#1==\finish} +% +% #1 is (maybe) the \floatmagic string. If so, #2 will be the +% (safe) float type for this float. We set \iffloattype to #2. +% +\def\doiffloat#1=#2=#3\finish{% + \def\temp{#1}% + \def\iffloattype{#2}% + \ifx\temp\floatmagic +} + +% @listoffloats FLOATTYPE - print a list of floats like a table of contents. +% +\parseargdef\listoffloats{% + \def\floattype{#1}% floattype + {% + % the floattype might have accents or other special characters, + % but we need to use it in a control sequence name. + \indexnofonts + \turnoffactive + \xdef\safefloattype{\floattype}% + }% + % + % \xrdef saves the floats as a \do-list in \floatlistSAFEFLOATTYPE. + \expandafter\ifx\csname floatlist\safefloattype\endcsname \relax + \ifhavexrefs + % if the user said @listoffloats foo but never @float foo. + \message{\linenumber No `\safefloattype' floats to list.}% + \fi + \else + \begingroup + \leftskip=\tocindent % indent these entries like a toc + \let\do=\listoffloatsdo + \csname floatlist\safefloattype\endcsname + \endgroup + \fi +} + +% This is called on each entry in a list of floats. We're passed the +% xref label, in the form LABEL-title, which is how we save it in the +% aux file. We strip off the -title and look up \XRLABEL-lof, which +% has the text we're supposed to typeset here. +% +% Figures without xref labels will not be included in the list (since +% they won't appear in the aux file). +% +\def\listoffloatsdo#1{\listoffloatsdoentry#1\finish} +\def\listoffloatsdoentry#1-title\finish{{% + % Can't fully expand XR#1-lof because it can contain anything. Just + % pass the control sequence. On the other hand, XR#1-pg is just the + % page number, and we want to fully expand that so we can get a link + % in pdf output. + \toksA = \expandafter{\csname XR#1-lof\endcsname}% + % + % use the same \entry macro we use to generate the TOC and index. + \edef\writeentry{\noexpand\entry{\the\toksA}{\csname XR#1-pg\endcsname}}% + \writeentry +}} + +\message{localization,} +% and i18n. + +% @documentlanguage is usually given very early, just after +% @setfilename. If done too late, it may not override everything +% properly. Single argument is the language abbreviation. +% It would be nice if we could set up a hyphenation file here. +% +\parseargdef\documentlanguage{% + \tex % read txi-??.tex file in plain TeX. + % Read the file if it exists. + \openin 1 txi-#1.tex + \ifeof 1 + \errhelp = \nolanghelp + \errmessage{Cannot read language file txi-#1.tex}% + \else + \input txi-#1.tex + \fi + \closein 1 + \endgroup +} +\newhelp\nolanghelp{The given language definition file cannot be found or +is empty. Maybe you need to install it? In the current directory +should work if nowhere else does.} + + +% @documentencoding should change something in TeX eventually, most +% likely, but for now just recognize it. +\let\documentencoding = \comment + + +% Page size parameters. +% +\newdimen\defaultparindent \defaultparindent = 15pt + +\chapheadingskip = 15pt plus 4pt minus 2pt +\secheadingskip = 12pt plus 3pt minus 2pt +\subsecheadingskip = 9pt plus 2pt minus 2pt + +% Prevent underfull vbox error messages. +\vbadness = 10000 + +% Don't be so finicky about underfull hboxes, either. +\hbadness = 2000 + +% Following George Bush, just get rid of widows and orphans. +\widowpenalty=10000 +\clubpenalty=10000 + +% Use TeX 3.0's \emergencystretch to help line breaking, but if we're +% using an old version of TeX, don't do anything. We want the amount of +% stretch added to depend on the line length, hence the dependence on +% \hsize. We call this whenever the paper size is set. +% +\def\setemergencystretch{% + \ifx\emergencystretch\thisisundefined + % Allow us to assign to \emergencystretch anyway. + \def\emergencystretch{\dimen0}% + \else + \emergencystretch = .15\hsize + \fi +} + +% Parameters in order: 1) textheight; 2) textwidth; +% 3) voffset; 4) hoffset; 5) binding offset; 6) topskip; +% 7) physical page height; 8) physical page width. +% +% We also call \setleading{\textleading}, so the caller should define +% \textleading. The caller should also set \parskip. +% +\def\internalpagesizes#1#2#3#4#5#6#7#8{% + \voffset = #3\relax + \topskip = #6\relax + \splittopskip = \topskip + % + \vsize = #1\relax + \advance\vsize by \topskip + \outervsize = \vsize + \advance\outervsize by 2\topandbottommargin + \pageheight = \vsize + % + \hsize = #2\relax + \outerhsize = \hsize + \advance\outerhsize by 0.5in + \pagewidth = \hsize + % + \normaloffset = #4\relax + \bindingoffset = #5\relax + % + \ifpdf + \pdfpageheight #7\relax + \pdfpagewidth #8\relax + \fi + % + \setleading{\textleading} + % + \parindent = \defaultparindent + \setemergencystretch +} + +% @letterpaper (the default). +\def\letterpaper{{\globaldefs = 1 + \parskip = 3pt plus 2pt minus 1pt + \textleading = 13.2pt + % + % If page is nothing but text, make it come out even. + \internalpagesizes{46\baselineskip}{6in}% + {\voffset}{.25in}% + {\bindingoffset}{36pt}% + {11in}{8.5in}% +}} + +% Use @smallbook to reset parameters for 7x9.25 trim size. +\def\smallbook{{\globaldefs = 1 + \parskip = 2pt plus 1pt + \textleading = 12pt + % + \internalpagesizes{7.5in}{5in}% + {\voffset}{.25in}% + {\bindingoffset}{16pt}% + {9.25in}{7in}% + % + \lispnarrowing = 0.3in + \tolerance = 700 + \hfuzz = 1pt + \contentsrightmargin = 0pt + \defbodyindent = .5cm +}} + +% Use @smallerbook to reset parameters for 6x9 trim size. +% (Just testing, parameters still in flux.) +\def\smallerbook{{\globaldefs = 1 + \parskip = 1.5pt plus 1pt + \textleading = 12pt + % + \internalpagesizes{7.4in}{4.8in}% + {-.2in}{-.4in}% + {0pt}{14pt}% + {9in}{6in}% + % + \lispnarrowing = 0.25in + \tolerance = 700 + \hfuzz = 1pt + \contentsrightmargin = 0pt + \defbodyindent = .4cm +}} + +% Use @afourpaper to print on European A4 paper. +\def\afourpaper{{\globaldefs = 1 + \parskip = 3pt plus 2pt minus 1pt + \textleading = 13.2pt + % + % Double-side printing via postscript on Laserjet 4050 + % prints double-sided nicely when \bindingoffset=10mm and \hoffset=-6mm. + % To change the settings for a different printer or situation, adjust + % \normaloffset until the front-side and back-side texts align. Then + % do the same for \bindingoffset. You can set these for testing in + % your texinfo source file like this: + % @tex + % \global\normaloffset = -6mm + % \global\bindingoffset = 10mm + % @end tex + \internalpagesizes{51\baselineskip}{160mm} + {\voffset}{\hoffset}% + {\bindingoffset}{44pt}% + {297mm}{210mm}% + % + \tolerance = 700 + \hfuzz = 1pt + \contentsrightmargin = 0pt + \defbodyindent = 5mm +}} + +% Use @afivepaper to print on European A5 paper. +% From romildo@urano.iceb.ufop.br, 2 July 2000. +% He also recommends making @example and @lisp be small. +\def\afivepaper{{\globaldefs = 1 + \parskip = 2pt plus 1pt minus 0.1pt + \textleading = 12.5pt + % + \internalpagesizes{160mm}{120mm}% + {\voffset}{\hoffset}% + {\bindingoffset}{8pt}% + {210mm}{148mm}% + % + \lispnarrowing = 0.2in + \tolerance = 800 + \hfuzz = 1.2pt + \contentsrightmargin = 0pt + \defbodyindent = 2mm + \tableindent = 12mm +}} + +% A specific text layout, 24x15cm overall, intended for A4 paper. +\def\afourlatex{{\globaldefs = 1 + \afourpaper + \internalpagesizes{237mm}{150mm}% + {\voffset}{4.6mm}% + {\bindingoffset}{7mm}% + {297mm}{210mm}% + % + % Must explicitly reset to 0 because we call \afourpaper. + \globaldefs = 0 +}} + +% Use @afourwide to print on A4 paper in landscape format. +\def\afourwide{{\globaldefs = 1 + \afourpaper + \internalpagesizes{241mm}{165mm}% + {\voffset}{-2.95mm}% + {\bindingoffset}{7mm}% + {297mm}{210mm}% + \globaldefs = 0 +}} + +% @pagesizes TEXTHEIGHT[,TEXTWIDTH] +% Perhaps we should allow setting the margins, \topskip, \parskip, +% and/or leading, also. Or perhaps we should compute them somehow. +% +\parseargdef\pagesizes{\pagesizesyyy #1,,\finish} +\def\pagesizesyyy#1,#2,#3\finish{{% + \setbox0 = \hbox{\ignorespaces #2}\ifdim\wd0 > 0pt \hsize=#2\relax \fi + \globaldefs = 1 + % + \parskip = 3pt plus 2pt minus 1pt + \setleading{\textleading}% + % + \dimen0 = #1 + \advance\dimen0 by \voffset + % + \dimen2 = \hsize + \advance\dimen2 by \normaloffset + % + \internalpagesizes{#1}{\hsize}% + {\voffset}{\normaloffset}% + {\bindingoffset}{44pt}% + {\dimen0}{\dimen2}% +}} + +% Set default to letter. +% +\letterpaper + + +\message{and turning on texinfo input format.} + +% Define macros to output various characters with catcode for normal text. +\catcode`\"=\other +\catcode`\~=\other +\catcode`\^=\other +\catcode`\_=\other +\catcode`\|=\other +\catcode`\<=\other +\catcode`\>=\other +\catcode`\+=\other +\catcode`\$=\other +\def\normaldoublequote{"} +\def\normaltilde{~} +\def\normalcaret{^} +\def\normalunderscore{_} +\def\normalverticalbar{|} +\def\normalless{<} +\def\normalgreater{>} +\def\normalplus{+} +\def\normaldollar{$}%$ font-lock fix + +% This macro is used to make a character print one way in \tt +% (where it can probably be output as-is), and another way in other fonts, +% where something hairier probably needs to be done. +% +% #1 is what to print if we are indeed using \tt; #2 is what to print +% otherwise. Since all the Computer Modern typewriter fonts have zero +% interword stretch (and shrink), and it is reasonable to expect all +% typewriter fonts to have this, we can check that font parameter. +% +\def\ifusingtt#1#2{\ifdim \fontdimen3\font=0pt #1\else #2\fi} + +% Same as above, but check for italic font. Actually this also catches +% non-italic slanted fonts since it is impossible to distinguish them from +% italic fonts. But since this is only used by $ and it uses \sl anyway +% this is not a problem. +\def\ifusingit#1#2{\ifdim \fontdimen1\font>0pt #1\else #2\fi} + +% Turn off all special characters except @ +% (and those which the user can use as if they were ordinary). +% Most of these we simply print from the \tt font, but for some, we can +% use math or other variants that look better in normal text. + +\catcode`\"=\active +\def\activedoublequote{{\tt\char34}} +\let"=\activedoublequote +\catcode`\~=\active +\def~{{\tt\char126}} +\chardef\hat=`\^ +\catcode`\^=\active +\def^{{\tt \hat}} + +\catcode`\_=\active +\def_{\ifusingtt\normalunderscore\_} +\let\realunder=_ +% Subroutine for the previous macro. +\def\_{\leavevmode \kern.07em \vbox{\hrule width.3em height.1ex}\kern .07em } + +\catcode`\|=\active +\def|{{\tt\char124}} +\chardef \less=`\< +\catcode`\<=\active +\def<{{\tt \less}} +\chardef \gtr=`\> +\catcode`\>=\active +\def>{{\tt \gtr}} +\catcode`\+=\active +\def+{{\tt \char 43}} +\catcode`\$=\active +\def${\ifusingit{{\sl\$}}\normaldollar}%$ font-lock fix + +% If a .fmt file is being used, characters that might appear in a file +% name cannot be active until we have parsed the command line. +% So turn them off again, and have \everyjob (or @setfilename) turn them on. +% \otherifyactive is called near the end of this file. +\def\otherifyactive{\catcode`+=\other \catcode`\_=\other} + +\catcode`\@=0 + +% \backslashcurfont outputs one backslash character in current font, +% as in \char`\\. +\global\chardef\backslashcurfont=`\\ +\global\let\rawbackslashxx=\backslashcurfont % let existing .??s files work + +% \rawbackslash defines an active \ to do \backslashcurfont. +% \otherbackslash defines an active \ to be a literal `\' character with +% catcode other. +{\catcode`\\=\active + @gdef@rawbackslash{@let\=@backslashcurfont} + @gdef@otherbackslash{@let\=@realbackslash} +} + +% \realbackslash is an actual character `\' with catcode other, and +% \doublebackslash is two of them (for the pdf outlines). +{\catcode`\\=\other @gdef@realbackslash{\} @gdef@doublebackslash{\\}} + +% \normalbackslash outputs one backslash in fixed width font. +\def\normalbackslash{{\tt\backslashcurfont}} + +\catcode`\\=\active + +% Used sometimes to turn off (effectively) the active characters +% even after parsing them. +@def@turnoffactive{% + @let"=@normaldoublequote + @let\=@realbackslash + @let~=@normaltilde + @let^=@normalcaret + @let_=@normalunderscore + @let|=@normalverticalbar + @let<=@normalless + @let>=@normalgreater + @let+=@normalplus + @let$=@normaldollar %$ font-lock fix + @unsepspaces +} + +% Same as @turnoffactive except outputs \ as {\tt\char`\\} instead of +% the literal character `\'. (Thus, \ is not expandable when this is in +% effect.) +% +@def@normalturnoffactive{@turnoffactive @let\=@normalbackslash} + +% Make _ and + \other characters, temporarily. +% This is canceled by @fixbackslash. +@otherifyactive + +% If a .fmt file is being used, we don't want the `\input texinfo' to show up. +% That is what \eatinput is for; after that, the `\' should revert to printing +% a backslash. +% +@gdef@eatinput input texinfo{@fixbackslash} +@global@let\ = @eatinput + +% On the other hand, perhaps the file did not have a `\input texinfo'. Then +% the first `\{ in the file would cause an error. This macro tries to fix +% that, assuming it is called before the first `\' could plausibly occur. +% Also turn back on active characters that might appear in the input +% file name, in case not using a pre-dumped format. +% +@gdef@fixbackslash{% + @ifx\@eatinput @let\ = @normalbackslash @fi + @catcode`+=@active + @catcode`@_=@active +} + +% Say @foo, not \foo, in error messages. +@escapechar = `@@ + +% These look ok in all fonts, so just make them not special. +@catcode`@& = @other +@catcode`@# = @other +@catcode`@% = @other + + +@c Local variables: +@c eval: (add-hook 'write-file-hooks 'time-stamp) +@c page-delimiter: "^\\\\message" +@c time-stamp-start: "def\\\\texinfoversion{" +@c time-stamp-format: "%:y-%02m-%02d.%02H" +@c time-stamp-end: "}" +@c End: + +@c vim:sw=2: + +@ignore + arch-tag: e1b36e32-c96e-4135-a41a-0b2efa2ea115 +@end ignore diff --git a/gcc-4.2.1-5666.3/gcc/doc/install-old.texi b/gcc-4.2.1-5666.3/gcc/doc/install-old.texi new file mode 100644 index 000000000..0a4afbe45 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/install-old.texi @@ -0,0 +1,194 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file install.texi. + +@ifnothtml +@comment node-name, next, previous, up +@node Old, GNU Free Documentation License, Specific, Top +@end ifnothtml +@html +<h1 align="center">Old installation documentation</h1> +@end html +@ifnothtml +@chapter Old installation documentation +@end ifnothtml + +Note most of this information is out of date and superseded by the +previous chapters of this manual. It is provided for historical +reference only, because of a lack of volunteers to merge it into the +main manual. + +@ifnothtml +@menu +* Configurations:: Configurations Supported by GCC. +@end menu +@end ifnothtml + +Here is the procedure for installing GCC on a GNU or Unix system. + +@enumerate +@item +If you have chosen a configuration for GCC which requires other GNU +tools (such as GAS or the GNU linker) instead of the standard system +tools, install the required tools in the build directory under the names +@file{as}, @file{ld} or whatever is appropriate. + +Alternatively, you can do subsequent compilation using a value of the +@code{PATH} environment variable such that the necessary GNU tools come +before the standard system tools. + +@item +Specify the host, build and target machine configurations. You do this +when you run the @file{configure} script. + +The @dfn{build} machine is the system which you are using, the +@dfn{host} machine is the system where you want to run the resulting +compiler (normally the build machine), and the @dfn{target} machine is +the system for which you want the compiler to generate code. + +If you are building a compiler to produce code for the machine it runs +on (a native compiler), you normally do not need to specify any operands +to @file{configure}; it will try to guess the type of machine you are on +and use that as the build, host and target machines. So you don't need +to specify a configuration when building a native compiler unless +@file{configure} cannot figure out what your configuration is or guesses +wrong. + +In those cases, specify the build machine's @dfn{configuration name} +with the @option{--host} option; the host and target will default to be +the same as the host machine. + +Here is an example: + +@smallexample +./configure --host=sparc-sun-sunos4.1 +@end smallexample + +A configuration name may be canonical or it may be more or less +abbreviated. + +A canonical configuration name has three parts, separated by dashes. +It looks like this: @samp{@var{cpu}-@var{company}-@var{system}}. +(The three parts may themselves contain dashes; @file{configure} +can figure out which dashes serve which purpose.) For example, +@samp{m68k-sun-sunos4.1} specifies a Sun 3. + +You can also replace parts of the configuration by nicknames or aliases. +For example, @samp{sun3} stands for @samp{m68k-sun}, so +@samp{sun3-sunos4.1} is another way to specify a Sun 3. + +You can specify a version number after any of the system types, and some +of the CPU types. In most cases, the version is irrelevant, and will be +ignored. So you might as well specify the version if you know it. + +See @ref{Configurations}, for a list of supported configuration names and +notes on many of the configurations. You should check the notes in that +section before proceeding any further with the installation of GCC@. + +@end enumerate + +@ifnothtml +@node Configurations, , , Old +@section Configurations Supported by GCC +@end ifnothtml +@html +<h2>@anchor{Configurations}Configurations Supported by GCC</h2> +@end html +@cindex configurations supported by GCC + +Here are the possible CPU types: + +@quotation +@c gmicro, fx80, spur and tahoe omitted since they don't work. +1750a, a29k, alpha, arm, avr, c@var{n}, clipper, dsp16xx, elxsi, fr30, h8300, +hppa1.0, hppa1.1, i370, i386, i486, i586, i686, i786, i860, i960, ip2k, m32r, +m68000, m68k, m6811, m6812, m88k, mcore, mips, mipsel, mips64, mips64el, +mn10200, mn10300, ns32k, pdp11, powerpc, powerpcle, romp, rs6000, sh, sparc, +sparclite, sparc64, v850, vax, we32k. +@end quotation + +Here are the recognized company names. As you can see, customary +abbreviations are used rather than the longer official names. + +@c What should be done about merlin, tek*, dolphin? +@quotation +acorn, alliant, altos, apollo, apple, att, bull, +cbm, convergent, convex, crds, dec, dg, dolphin, +elxsi, encore, harris, hitachi, hp, ibm, intergraph, isi, +mips, motorola, ncr, next, ns, omron, plexus, +sequent, sgi, sony, sun, tti, unicom, wrs. +@end quotation + +The company name is meaningful only to disambiguate when the rest of +the information supplied is insufficient. You can omit it, writing +just @samp{@var{cpu}-@var{system}}, if it is not needed. For example, +@samp{vax-ultrix4.2} is equivalent to @samp{vax-dec-ultrix4.2}. + +Here is a list of system types: + +@quotation +386bsd, aix, acis, amigaos, aos, aout, aux, bosx, bsd, clix, coff, ctix, cxux, +dgux, dynix, ebmon, ecoff, elf, esix, freebsd, hms, genix, gnu, linux, +linux-gnu, hiux, hpux, iris, irix, isc, luna, lynxos, mach, minix, msdos, mvs, +netbsd, newsos, nindy, ns, osf, osfrose, ptx, riscix, riscos, rtu, sco, sim, +solaris, sunos, sym, sysv, udi, ultrix, unicos, uniplus, unos, vms, vsta, +vxworks, winnt, xenix. +@end quotation + +@noindent +You can omit the system type; then @file{configure} guesses the +operating system from the CPU and company. + +You can add a version number to the system type; this may or may not +make a difference. For example, you can write @samp{bsd4.3} or +@samp{bsd4.4} to distinguish versions of BSD@. In practice, the version +number is most needed for @samp{sysv3} and @samp{sysv4}, which are often +treated differently. + +@samp{linux-gnu} is the canonical name for the GNU/Linux target; however +GCC will also accept @samp{linux}. The version of the kernel in use is +not relevant on these systems. A suffix such as @samp{libc1} or @samp{aout} +distinguishes major versions of the C library; all of the suffixed versions +are obsolete. + +If you specify an impossible combination such as @samp{i860-dg-vms}, +then you may get an error message from @file{configure}, or it may +ignore part of the information and do the best it can with the rest. +@file{configure} always prints the canonical name for the alternative +that it used. GCC does not support all possible alternatives. + +Often a particular model of machine has a name. Many machine names are +recognized as aliases for CPU/company combinations. Thus, the machine +name @samp{sun3}, mentioned above, is an alias for @samp{m68k-sun}. +Sometimes we accept a company name as a machine name, when the name is +popularly used for a particular machine. Here is a table of the known +machine names: + +@quotation +3300, 3b1, 3b@var{n}, 7300, altos3068, altos, +apollo68, att-7300, balance, +convex-c@var{n}, crds, decstation-3100, +decstation, delta, encore, +fx2800, gmicro, hp7@var{nn}, hp8@var{nn}, +hp9k2@var{nn}, hp9k3@var{nn}, hp9k7@var{nn}, +hp9k8@var{nn}, iris4d, iris, isi68, +m3230, magnum, merlin, miniframe, +mmax, news-3600, news800, news, next, +pbd, pc532, pmax, powerpc, powerpcle, ps2, risc-news, +rtpc, sun2, sun386i, sun386, sun3, +sun4, symmetry, tower-32, tower. +@end quotation + +@noindent +Remember that a machine name specifies both the cpu type and the company +name. +If you want to install your own homemade configuration files, you can +use @samp{local} as the company name to access them. If you use +configuration @samp{@var{cpu}-local}, the configuration name +without the cpu prefix +is used to form the configuration file names. + +Thus, if you specify @samp{m68k-local}, configuration uses +files @file{m68k.md}, @file{local.h}, @file{m68k.c}, +@file{xm-local.h}, @file{t-local}, and @file{x-local}, all in the +directory @file{config/m68k}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/install.texi b/gcc-4.2.1-5666.3/gcc/doc/install.texi new file mode 100644 index 000000000..7b22d7fc9 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/install.texi @@ -0,0 +1,4224 @@ +\input texinfo.tex @c -*-texinfo-*- +@c @ifnothtml +@c %**start of header +@setfilename gccinstall.info +@settitle Installing GCC +@setchapternewpage odd +@c %**end of header +@c @end ifnothtml + +@include gcc-common.texi + +@c Specify title for specific html page +@ifset indexhtml +@settitle Installing GCC +@end ifset +@ifset specifichtml +@settitle Host/Target specific installation notes for GCC +@end ifset +@ifset prerequisiteshtml +@settitle Prerequisites for GCC +@end ifset +@ifset downloadhtml +@settitle Downloading GCC +@end ifset +@ifset configurehtml +@settitle Installing GCC: Configuration +@end ifset +@ifset buildhtml +@settitle Installing GCC: Building +@end ifset +@ifset testhtml +@settitle Installing GCC: Testing +@end ifset +@ifset finalinstallhtml +@settitle Installing GCC: Final installation +@end ifset +@ifset binarieshtml +@settitle Installing GCC: Binaries +@end ifset +@ifset oldhtml +@settitle Installing GCC: Old documentation +@end ifset +@ifset gfdlhtml +@settitle Installing GCC: GNU Free Documentation License +@end ifset + +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. +@c *** Converted to texinfo by Dean Wakerley, dean@wakerley.com + +@c IMPORTANT: whenever you modify this file, run `install.texi2html' to +@c test the generation of HTML documents for the gcc.gnu.org web pages. +@c +@c Do not use @footnote{} in this file as it breaks install.texi2html! + +@c Include everything if we're not making html +@ifnothtml +@set indexhtml +@set specifichtml +@set prerequisiteshtml +@set downloadhtml +@set configurehtml +@set buildhtml +@set testhtml +@set finalinstallhtml +@set binarieshtml +@set oldhtml +@set gfdlhtml +@end ifnothtml + +@c Part 2 Summary Description and Copyright +@copying +Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. +@sp 1 +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no +Invariant Sections, the Front-Cover texts being (a) (see below), and +with the Back-Cover Texts being (b) (see below). A copy of the +license is included in the section entitled ``@uref{./gfdl.html,,GNU +Free Documentation License}''. + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@end copying +@ifinfo +@insertcopying +@end ifinfo +@dircategory Software development +@direntry +* gccinstall: (gccinstall). Installing the GNU Compiler Collection. +@end direntry + +@c Part 3 Titlepage and Copyright +@titlepage +@title Installing GCC +@versionsubtitle + +@c The following two commands start the copyright page. +@page +@vskip 0pt plus 1filll +@insertcopying +@end titlepage + +@c Part 4 Top node, Master Menu, and/or Table of Contents +@ifinfo +@node Top, , , (dir) +@comment node-name, next, Previous, up + +@menu +* Installing GCC:: This document describes the generic installation + procedure for GCC as well as detailing some target + specific installation instructions. + +* Specific:: Host/target specific installation notes for GCC. +* Binaries:: Where to get pre-compiled binaries. + +* Old:: Old installation documentation. + +* GNU Free Documentation License:: How you can copy and share this manual. +* Concept Index:: This index has two entries. +@end menu +@end ifinfo + +@iftex +@contents +@end iftex + +@c Part 5 The Body of the Document +@c ***Installing GCC********************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Installing GCC, Binaries, , Top +@end ifnothtml +@ifset indexhtml +@ifnothtml +@chapter Installing GCC +@end ifnothtml + +The latest version of this document is always available at +@uref{http://gcc.gnu.org/install/,,http://gcc.gnu.org/install/}. + +This document describes the generic installation procedure for GCC as well +as detailing some target specific installation instructions. + +GCC includes several components that previously were separate distributions +with their own installation instructions. This document supersedes all +package specific installation instructions. + +@emph{Before} starting the build/install procedure please check the +@ifnothtml +@ref{Specific, host/target specific installation notes}. +@end ifnothtml +@ifhtml +@uref{specific.html,,host/target specific installation notes}. +@end ifhtml +We recommend you browse the entire generic installation instructions before +you proceed. + +Lists of successful builds for released versions of GCC are +available at @uref{http://gcc.gnu.org/buildstat.html}. +These lists are updated as new information becomes available. + +The installation procedure itself is broken into five steps. + +@ifinfo +@menu +* Prerequisites:: +* Downloading the source:: +* Configuration:: +* Building:: +* Testing:: (optional) +* Final install:: +@end menu +@end ifinfo +@ifhtml +@enumerate +@item +@uref{prerequisites.html,,Prerequisites} +@item +@uref{download.html,,Downloading the source} +@item +@uref{configure.html,,Configuration} +@item +@uref{build.html,,Building} +@item +@uref{test.html,,Testing} (optional) +@item +@uref{finalinstall.html,,Final install} +@end enumerate +@end ifhtml + +Please note that GCC does not support @samp{make uninstall} and probably +won't do so in the near future as this would open a can of worms. Instead, +we suggest that you install GCC into a directory of its own and simply +remove that directory when you do not need that specific version of GCC +any longer, and, if shared libraries are installed there as well, no +more binaries exist that use them. + +@ifhtml +There are also some @uref{old.html,,old installation instructions}, +which are mostly obsolete but still contain some information which has +not yet been merged into the main part of this manual. +@end ifhtml + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} + +@insertcopying +@end ifhtml +@end ifset + +@c ***Prerequisites************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Prerequisites, Downloading the source, , Installing GCC +@end ifnothtml +@ifset prerequisiteshtml +@ifnothtml +@chapter Prerequisites +@end ifnothtml +@cindex Prerequisites + +GCC requires that various tools and packages be available for use in the +build procedure. Modifying GCC sources requires additional tools +described below. + +@heading Tools/packages necessary for building GCC +@table @asis +@item ISO C90 compiler +Necessary to bootstrap GCC, although versions of GCC prior +to 3.4 also allow bootstrapping with a traditional (K&R) C compiler. + +To build all languages in a cross-compiler or other configuration where +3-stage bootstrap is not performed, you need to start with an existing +GCC binary (version 2.95 or later) because source code for language +frontends other than C might use GCC extensions. + +@item GNAT + +In order to build the Ada compiler (GNAT) you must already have GNAT +installed because portions of the Ada frontend are written in Ada (with +GNAT extensions.) Refer to the Ada installation instructions for more +specific information. + +@item A ``working'' POSIX compatible shell, or GNU bash + +Necessary when running @command{configure} because some +@command{/bin/sh} shells have bugs and may crash when configuring the +target libraries. In other cases, @command{/bin/sh} or @command{ksh} +have disastrous corner-case performance problems. This +can cause target @command{configure} runs to literally take days to +complete in some cases. + +So on some platforms @command{/bin/ksh} is sufficient, on others it +isn't. See the host/target specific instructions for your platform, or +use @command{bash} to be sure. Then set @env{CONFIG_SHELL} in your +environment to your ``good'' shell prior to running +@command{configure}/@command{make}. + +@command{zsh} is not a fully compliant POSIX shell and will not +work when configuring GCC@. + +@item GNU binutils + +Necessary in some circumstances, optional in others. See the +host/target specific instructions for your platform for the exact +requirements. + +@item gzip version 1.2.4 (or later) or +@itemx bzip2 version 1.0.2 (or later) + +Necessary to uncompress GCC @command{tar} files when source code is +obtained via FTP mirror sites. + +@item GNU make version 3.79.1 (or later) + +You must have GNU make installed to build GCC@. + +@item GNU tar version 1.14 (or later) + +Necessary (only on some platforms) to untar the source code. Many +systems' @command{tar} programs will also work, only try GNU +@command{tar} if you have problems. + +@item GNU Multiple Precision Library (GMP) version 4.1 (or later) + +Necessary to build the Fortran frontend. If you do not have it +installed in your library search path, you will have to configure with +the @option{--with-gmp} configure option. See also +@option{--with-gmp-lib} and @option{--with-gmp-include}. + +@item MPFR Library version 2.2.1 (or later) + +Necessary to build the Fortran frontend. It can be downloaded from +@uref{http://www.mpfr.org/}. The version of MPFR that is bundled with +GMP 4.1.x contains numerous bugs. Although GNU Fortran will appear +to function with the buggy versions of MPFR, there are a few GNU Fortran +bugs that will not be fixed when using this version. It is strongly +recommended to upgrade to the recommended version of MPFR. + +The @option{--with-mpfr} configure option should be used if your MPFR +Library is not installed in your default library search path. See +also @option{--with-mpfr-lib} and @option{--with-mpfr-include}. + +@item @command{jar}, or InfoZIP (@command{zip} and @command{unzip}) + +Necessary to build libgcj, the GCJ runtime. + +@end table + + +@heading Tools/packages necessary for modifying GCC +@table @asis +@item autoconf versions 2.13 and 2.59 +@itemx GNU m4 version 1.4 (or later) + +Necessary when modifying @file{configure.ac}, @file{aclocal.m4}, etc.@: +to regenerate @file{configure} and @file{config.in} files. Most +directories require autoconf 2.59 (exactly), but the toplevel +still requires autoconf 2.13 (exactly). + +@item automake version 1.9.6 + +Necessary when modifying a @file{Makefile.am} file to regenerate its +associated @file{Makefile.in}. + +Much of GCC does not use automake, so directly edit the @file{Makefile.in} +file. Specifically this applies to the @file{gcc}, @file{intl}, +@file{libcpp}, @file{libiberty}, @file{libobjc} directories as well +as any of their subdirectories. + +For directories that use automake, GCC requires the latest release in +the 1.9.x series, which is currently 1.9.6. When regenerating a directory +to a newer version, please update all the directories using an older 1.9.x +to the latest released version. + +@item gettext version 0.14.5 (or later) + +Needed to regenerate @file{gcc.pot}. + +@item gperf version 2.7.2 (or later) + +Necessary when modifying @command{gperf} input files, e.g.@: +@file{gcc/cp/cfns.gperf} to regenerate its associated header file, e.g.@: +@file{gcc/cp/cfns.h}. + +@item DejaGnu 1.4.4 +@itemx Expect +@itemx Tcl + +Necessary to run the GCC testsuite; see the section on testing for details. + +@item autogen version 5.5.4 (or later) and +@itemx guile version 1.4.1 (or later) + +Necessary to regenerate @file{fixinc/fixincl.x} from +@file{fixinc/inclhack.def} and @file{fixinc/*.tpl}. + +Necessary to run @samp{make check} for @file{fixinc}. + +Necessary to regenerate the top level @file{Makefile.in} file from +@file{Makefile.tpl} and @file{Makefile.def}. + +@item GNU Bison version 1.28 (or later) +Berkeley @command{yacc} (@command{byacc}) is also reported to work other +than for GCJ. + +Necessary when modifying @file{*.y} files. + +Necessary to build GCC during development because the generated output +files are not included in the SVN repository. They are included in +releases. + +@item Flex version 2.5.4 (or later) + +Necessary when modifying @file{*.l} files. + +Necessary to build GCC during development because the generated output +files are not included in the SVN repository. They are included in +releases. + +@item Texinfo version 4.4 (or later) + +Necessary for running @command{makeinfo} when modifying @file{*.texi} +files to test your changes. + +Necessary for running @command{make dvi} or @command{make pdf} to +create printable documentation in DVI or PDF format. Texinfo version +4.8 or later is required for @command{make pdf}. + +Necessary to build GCC documentation during development because the +generated output files are not included in the SVN repository. They are +included in releases. + +@item @TeX{} (any working version) + +Necessary for running @command{texi2dvi} and @command{texi2pdf}, which +are used when running @command{make dvi} or @command{make pdf} to create +DVI or PDF files, respectively. + +@item SVN (any version) +@itemx SSH (any version) + +Necessary to access the SVN repository. Public releases and weekly +snapshots of the development sources are also available via FTP@. + +@item Perl version 5.6.1 (or later) + +Necessary when regenerating @file{Makefile} dependencies in libiberty. +Necessary when regenerating @file{libiberty/functions.texi}. +Necessary when generating manpages from Texinfo manuals. +Necessary when targetting Darwin, building libstdc++, +and not using @option{--disable-symvers}. +Used by various scripts to generate some files included in SVN (mainly +Unicode-related and rarely changing) from source tables. + +@item GNU diffutils version 2.7 (or later) + +Useful when submitting patches for the GCC source code. + +@item patch version 2.5.4 (or later) + +Necessary when applying patches, created with @command{diff}, to one's +own sources. + +@end table + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Downloading the source************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Downloading the source, Configuration, Prerequisites, Installing GCC +@end ifnothtml +@ifset downloadhtml +@ifnothtml +@chapter Downloading GCC +@end ifnothtml +@cindex Downloading GCC +@cindex Downloading the Source + +GCC is distributed via @uref{http://gcc.gnu.org/svn.html,,SVN} and FTP +tarballs compressed with @command{gzip} or +@command{bzip2}. It is possible to download a full distribution or specific +components. + +Please refer to the @uref{http://gcc.gnu.org/releases.html,,releases web page} +for information on how to obtain GCC@. + +The full distribution includes the C, C++, Objective-C, Fortran, Java, +and Ada (in the case of GCC 3.1 and later) compilers. The full +distribution also includes runtime libraries for C++, Objective-C, +Fortran, and Java. In GCC 3.0 and later versions, the GNU compiler +testsuites are also included in the full distribution. + +If you choose to download specific components, you must download the core +GCC distribution plus any language specific distributions you wish to +use. The core distribution includes the C language front end as well as the +shared components. Each language has a tarball which includes the language +front end as well as the language runtime (when appropriate). + +Unpack the core distribution as well as any language specific +distributions in the same directory. + +If you also intend to build binutils (either to upgrade an existing +installation or for use in place of the corresponding tools of your +OS), unpack the binutils distribution either in the same directory or +a separate one. In the latter case, add symbolic links to any +components of the binutils you intend to build alongside the compiler +(@file{bfd}, @file{binutils}, @file{gas}, @file{gprof}, @file{ld}, +@file{opcodes}, @dots{}) to the directory containing the GCC sources. + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Configuration*********************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Configuration, Building, Downloading the source, Installing GCC +@end ifnothtml +@ifset configurehtml +@ifnothtml +@chapter Installing GCC: Configuration +@end ifnothtml +@cindex Configuration +@cindex Installing GCC: Configuration + +Like most GNU software, GCC must be configured before it can be built. +This document describes the recommended configuration procedure +for both native and cross targets. + +We use @var{srcdir} to refer to the toplevel source directory for +GCC; we use @var{objdir} to refer to the toplevel build/object directory. + +If you obtained the sources via SVN, @var{srcdir} must refer to the top +@file{gcc} directory, the one where the @file{MAINTAINERS} can be found, +and not its @file{gcc} subdirectory, otherwise the build will fail. + +If either @var{srcdir} or @var{objdir} is located on an automounted NFS +file system, the shell's built-in @command{pwd} command will return +temporary pathnames. Using these can lead to various sorts of build +problems. To avoid this issue, set the @env{PWDCMD} environment +variable to an automounter-aware @command{pwd} command, e.g., +@command{pawd} or @samp{amq -w}, during the configuration and build +phases. + +First, we @strong{highly} recommend that GCC be built into a +separate directory than the sources which does @strong{not} reside +within the source tree. This is how we generally build GCC; building +where @var{srcdir} == @var{objdir} should still work, but doesn't +get extensive testing; building where @var{objdir} is a subdirectory +of @var{srcdir} is unsupported. + +If you have previously built GCC in the same directory for a +different target machine, do @samp{make distclean} to delete all files +that might be invalid. One of the files this deletes is @file{Makefile}; +if @samp{make distclean} complains that @file{Makefile} does not exist +or issues a message like ``don't know how to make distclean'' it probably +means that the directory is already suitably clean. However, with the +recommended method of building in a separate @var{objdir}, you should +simply use a different @var{objdir} for each target. + +Second, when configuring a native system, either @command{cc} or +@command{gcc} must be in your path or you must set @env{CC} in +your environment before running configure. Otherwise the configuration +scripts may fail. + +@ignore +Note that the bootstrap compiler and the resulting GCC must be link +compatible, else the bootstrap will fail with linker errors about +incompatible object file formats. Several multilibed targets are +affected by this requirement, see +@ifnothtml +@ref{Specific, host/target specific installation notes}. +@end ifnothtml +@ifhtml +@uref{specific.html,,host/target specific installation notes}. +@end ifhtml +@end ignore + +To configure GCC: + +@smallexample + % mkdir @var{objdir} + % cd @var{objdir} + % @var{srcdir}/configure [@var{options}] [@var{target}] +@end smallexample + + +@heading Target specification +@itemize @bullet +@item +GCC has code to correctly determine the correct value for @var{target} +for nearly all native systems. Therefore, we highly recommend you not +provide a configure target when configuring a native compiler. + +@item +@var{target} must be specified as @option{--target=@var{target}} +when configuring a cross compiler; examples of valid targets would be +m68k-coff, sh-elf, etc. + +@item +Specifying just @var{target} instead of @option{--target=@var{target}} +implies that the host defaults to @var{target}. +@end itemize + + +@heading Options specification + +Use @var{options} to override several configure time options for +GCC@. A list of supported @var{options} follows; @samp{configure +--help} may list other options, but those not listed below may not +work and should not normally be used. + +Note that each @option{--enable} option has a corresponding +@option{--disable} option and that each @option{--with} option has a +corresponding @option{--without} option. + +@table @code +@item --prefix=@var{dirname} +Specify the toplevel installation +directory. This is the recommended way to install the tools into a directory +other than the default. The toplevel installation directory defaults to +@file{/usr/local}. + +We @strong{highly} recommend against @var{dirname} being the same or a +subdirectory of @var{objdir} or vice versa. If specifying a directory +beneath a user's home directory tree, some shells will not expand +@var{dirname} correctly if it contains the @samp{~} metacharacter; use +@env{$HOME} instead. + +The following standard @command{autoconf} options are supported. Normally you +should not need to use these options. +@table @code +@item --exec-prefix=@var{dirname} +Specify the toplevel installation directory for architecture-dependent +files. The default is @file{@var{prefix}}. + +@item --bindir=@var{dirname} +Specify the installation directory for the executables called by users +(such as @command{gcc} and @command{g++}). The default is +@file{@var{exec-prefix}/bin}. + +@item --libdir=@var{dirname} +Specify the installation directory for object code libraries and +internal data files of GCC@. The default is @file{@var{exec-prefix}/lib}. + +@item --libexecdir=@var{dirname} +Specify the installation directory for internal executables of GCC@. + The default is @file{@var{exec-prefix}/libexec}. + +@item --with-slibdir=@var{dirname} +Specify the installation directory for the shared libgcc library. The +default is @file{@var{libdir}}. + +@item --infodir=@var{dirname} +Specify the installation directory for documentation in info format. +The default is @file{@var{prefix}/info}. + +@item --datadir=@var{dirname} +Specify the installation directory for some architecture-independent +data files referenced by GCC@. The default is @file{@var{prefix}/share}. + +@item --mandir=@var{dirname} +Specify the installation directory for manual pages. The default is +@file{@var{prefix}/man}. (Note that the manual pages are only extracts from +the full GCC manuals, which are provided in Texinfo format. The manpages +are derived by an automatic conversion process from parts of the full +manual.) + +@item --with-gxx-include-dir=@var{dirname} +Specify +the installation directory for G++ header files. The default is +@file{@var{prefix}/include/c++/@var{version}}. + +@end table + +@item --program-prefix=@var{prefix} +GCC supports some transformations of the names of its programs when +installing them. This option prepends @var{prefix} to the names of +programs to install in @var{bindir} (see above). For example, specifying +@option{--program-prefix=foo-} would result in @samp{gcc} +being installed as @file{/usr/local/bin/foo-gcc}. + +@item --program-suffix=@var{suffix} +Appends @var{suffix} to the names of programs to install in @var{bindir} +(see above). For example, specifying @option{--program-suffix=-3.1} +would result in @samp{gcc} being installed as +@file{/usr/local/bin/gcc-3.1}. + +@item --program-transform-name=@var{pattern} +Applies the @samp{sed} script @var{pattern} to be applied to the names +of programs to install in @var{bindir} (see above). @var{pattern} has to +consist of one or more basic @samp{sed} editing commands, separated by +semicolons. For example, if you want the @samp{gcc} program name to be +transformed to the installed program @file{/usr/local/bin/myowngcc} and +the @samp{g++} program name to be transformed to +@file{/usr/local/bin/gspecial++} without changing other program names, +you could use the pattern +@option{--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'} +to achieve this effect. + +All three options can be combined and used together, resulting in more +complex conversion patterns. As a basic rule, @var{prefix} (and +@var{suffix}) are prepended (appended) before further transformations +can happen with a special transformation script @var{pattern}. + +As currently implemented, this option only takes effect for native +builds; cross compiler binaries' names are not transformed even when a +transformation is explicitly asked for by one of these options. + +For native builds, some of the installed programs are also installed +with the target alias in front of their name, as in +@samp{i686-pc-linux-gnu-gcc}. All of the above transformations happen +before the target alias is prepended to the name---so, specifying +@option{--program-prefix=foo-} and @option{program-suffix=-3.1}, the +resulting binary would be installed as +@file{/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1}. + +As a last shortcoming, none of the installed Ada programs are +transformed yet, which will be fixed in some time. + +@item --with-local-prefix=@var{dirname} +Specify the +installation directory for local include files. The default is +@file{/usr/local}. Specify this option if you want the compiler to +search directory @file{@var{dirname}/include} for locally installed +header files @emph{instead} of @file{/usr/local/include}. + +You should specify @option{--with-local-prefix} @strong{only} if your +site has a different convention (not @file{/usr/local}) for where to put +site-specific files. + +The default value for @option{--with-local-prefix} is @file{/usr/local} +regardless of the value of @option{--prefix}. Specifying +@option{--prefix} has no effect on which directory GCC searches for +local header files. This may seem counterintuitive, but actually it is +logical. + +The purpose of @option{--prefix} is to specify where to @emph{install +GCC}. The local header files in @file{/usr/local/include}---if you put +any in that directory---are not part of GCC@. They are part of other +programs---perhaps many others. (GCC installs its own header files in +another directory which is based on the @option{--prefix} value.) + +Both the local-prefix include directory and the GCC-prefix include +directory are part of GCC's ``system include'' directories. Although these +two directories are not fixed, they need to be searched in the proper +order for the correct processing of the include_next directive. The +local-prefix include directory is searched before the GCC-prefix +include directory. Another characteristic of system include directories +is that pedantic warnings are turned off for headers in these directories. + +Some autoconf macros add @option{-I @var{directory}} options to the +compiler command line, to ensure that directories containing installed +packages' headers are searched. When @var{directory} is one of GCC's +system include directories, GCC will ignore the option so that system +directories continue to be processed in the correct order. This +may result in a search order different from what was specified but the +directory will still be searched. + +GCC automatically searches for ordinary libraries using +@env{GCC_EXEC_PREFIX}. Thus, when the same installation prefix is +used for both GCC and packages, GCC will automatically search for +both headers and libraries. This provides a configuration that is +easy to use. GCC behaves in a manner similar to that when it is +installed as a system compiler in @file{/usr}. + +Sites that need to install multiple versions of GCC may not want to +use the above simple configuration. It is possible to use the +@option{--program-prefix}, @option{--program-suffix} and +@option{--program-transform-name} options to install multiple versions +into a single directory, but it may be simpler to use different prefixes +and the @option{--with-local-prefix} option to specify the location of the +site-specific files for each version. It will then be necessary for +users to specify explicitly the location of local site libraries +(e.g., with @env{LIBRARY_PATH}). + +The same value can be used for both @option{--with-local-prefix} and +@option{--prefix} provided it is not @file{/usr}. This can be used +to avoid the default search of @file{/usr/local/include}. + +@strong{Do not} specify @file{/usr} as the @option{--with-local-prefix}! +The directory you use for @option{--with-local-prefix} @strong{must not} +contain any of the system's standard header files. If it did contain +them, certain programs would be miscompiled (including GNU Emacs, on +certain targets), because this would override and nullify the header +file corrections made by the @command{fixincludes} script. + +Indications are that people who use this option use it based on mistaken +ideas of what it is for. People use it as if it specified where to +install part of GCC@. Perhaps they make this assumption because +installing GCC creates the directory. + +@item --enable-shared[=@var{package}[,@dots{}]] +Build shared versions of libraries, if shared libraries are supported on +the target platform. Unlike GCC 2.95.x and earlier, shared libraries +are enabled by default on all platforms that support shared libraries. + +If a list of packages is given as an argument, build shared libraries +only for the listed packages. For other packages, only static libraries +will be built. Package names currently recognized in the GCC tree are +@samp{libgcc} (also known as @samp{gcc}), @samp{libstdc++} (not +@samp{libstdc++-v3}), @samp{libffi}, @samp{zlib}, @samp{boehm-gc}, +@samp{ada}, @samp{libada}, @samp{libjava} and @samp{libobjc}. +Note @samp{libiberty} does not support shared libraries at all. + +Use @option{--disable-shared} to build only static libraries. Note that +@option{--disable-shared} does not accept a list of package names as +argument, only @option{--enable-shared} does. + +@item @anchor{with-gnu-as}--with-gnu-as +Specify that the compiler should assume that the +assembler it finds is the GNU assembler. However, this does not modify +the rules to find an assembler and will result in confusion if the +assembler found is not actually the GNU assembler. (Confusion may also +result if the compiler finds the GNU assembler but has not been +configured with @option{--with-gnu-as}.) If you have more than one +assembler installed on your system, you may want to use this option in +connection with @option{--with-as=@var{pathname}} or +@option{--with-build-time-tools=@var{pathname}}. + +The following systems are the only ones where it makes a difference +whether you use the GNU assembler. On any other system, +@option{--with-gnu-as} has no effect. + +@itemize @bullet +@item @samp{hppa1.0-@var{any}-@var{any}} +@item @samp{hppa1.1-@var{any}-@var{any}} +@item @samp{i386-@var{any}-sysv} +@item @samp{m68k-bull-sysv} +@item @samp{m68k-hp-hpux} +@item @samp{m68000-hp-hpux} +@item @samp{m68000-att-sysv} +@item @samp{sparc-sun-solaris2.@var{any}} +@item @samp{sparc64-@var{any}-solaris2.@var{any}} +@end itemize + +On the systems listed above (except for the HP-PA, the SPARC, for ISC on +the 386, if you use the GNU assembler, you should also use the GNU linker +(and specify @option{--with-gnu-ld}). + +@item @anchor{with-as}--with-as=@var{pathname} +Specify that the compiler should use the assembler pointed to by +@var{pathname}, rather than the one found by the standard rules to find +an assembler, which are: +@itemize @bullet +@item +Unless GCC is being built with a cross compiler, check the +@file{@var{libexec}/gcc/@var{target}/@var{version}} directory. +@var{libexec} defaults to @file{@var{exec-prefix}/libexec}; +@var{exec-prefix} defaults to @var{prefix}, which +defaults to @file{/usr/local} unless overridden by the +@option{--prefix=@var{pathname}} switch described above. @var{target} +is the target system triple, such as @samp{sparc-sun-solaris2.7}, and +@var{version} denotes the GCC version, such as 3.0. + +@item +If the target system is the same that you are building on, check +operating system specific directories (e.g.@: @file{/usr/ccs/bin} on +Sun Solaris 2). + +@item +Check in the @env{PATH} for a tool whose name is prefixed by the +target system triple. + +@item +Check in the @env{PATH} for a tool whose name is not prefixed by the +target system triple, if the host and target system triple are +the same (in other words, we use a host tool if it can be used for +the target as well). +@end itemize + +You may want to use @option{--with-as} if no assembler +is installed in the directories listed above, or if you have multiple +assemblers installed and want to choose one that is not found by the +above rules. + +@item @anchor{with-gnu-ld}--with-gnu-ld +Same as @uref{#with-gnu-as,,@option{--with-gnu-as}} +but for the linker. + +@item --with-ld=@var{pathname} +Same as @uref{#with-as,,@option{--with-as}} +but for the linker. + +@item --with-stabs +Specify that stabs debugging +information should be used instead of whatever format the host normally +uses. Normally GCC uses the same debug format as the host system. + +On MIPS based systems and on Alphas, you must specify whether you want +GCC to create the normal ECOFF debugging format, or to use BSD-style +stabs passed through the ECOFF symbol table. The normal ECOFF debug +format cannot fully handle languages other than C@. BSD stabs format can +handle other languages, but it only works with the GNU debugger GDB@. + +Normally, GCC uses the ECOFF debugging format by default; if you +prefer BSD stabs, specify @option{--with-stabs} when you configure GCC@. + +No matter which default you choose when you configure GCC, the user +can use the @option{-gcoff} and @option{-gstabs+} options to specify explicitly +the debug format for a particular compilation. + +@option{--with-stabs} is meaningful on the ISC system on the 386, also, if +@option{--with-gas} is used. It selects use of stabs debugging +information embedded in COFF output. This kind of debugging information +supports C++ well; ordinary COFF debugging information does not. + +@option{--with-stabs} is also meaningful on 386 systems running SVR4. It +selects use of stabs debugging information embedded in ELF output. The +C++ compiler currently (2.6.0) does not support the DWARF debugging +information normally used on 386 SVR4 platforms; stabs provide a +workable alternative. This requires gas and gdb, as the normal SVR4 +tools can not generate or interpret stabs. + +@item --disable-multilib +Specify that multiple target +libraries to support different target variants, calling +conventions, etc.@: should not be built. The default is to build a +predefined set of them. + +Some targets provide finer-grained control over which multilibs are built +(e.g., @option{--disable-softfloat}): +@table @code +@item arc-*-elf* +biendian. + +@item arm-*-* +fpu, 26bit, underscore, interwork, biendian, nofmult. + +@item m68*-*-* +softfloat, m68881, m68000, m68020. + +@item mips*-*-* +single-float, biendian, softfloat. + +@item powerpc*-*-*, rs6000*-*-* +aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, +sysv, aix. + +@end table + +@item --enable-threads +Specify that the target +supports threads. This affects the Objective-C compiler and runtime +library, and exception handling for other languages like C++ and Java. +On some systems, this is the default. + +In general, the best (and, in many cases, the only known) threading +model available will be configured for use. Beware that on some +systems, GCC has not been taught what threading models are generally +available for the system. In this case, @option{--enable-threads} is an +alias for @option{--enable-threads=single}. + +@item --disable-threads +Specify that threading support should be disabled for the system. +This is an alias for @option{--enable-threads=single}. + +@item --enable-threads=@var{lib} +Specify that +@var{lib} is the thread support library. This affects the Objective-C +compiler and runtime library, and exception handling for other languages +like C++ and Java. The possibilities for @var{lib} are: + +@table @code +@item aix +AIX thread support. +@item dce +DCE thread support. +@item gnat +Ada tasking support. For non-Ada programs, this setting is equivalent +to @samp{single}. When used in conjunction with the Ada run time, it +causes GCC to use the same thread primitives as Ada uses. This option +is necessary when using both Ada and the back end exception handling, +which is the default for most Ada targets. +@item mach +Generic MACH thread support, known to work on NeXTSTEP@. (Please note +that the file needed to support this configuration, @file{gthr-mach.h}, is +missing and thus this setting will cause a known bootstrap failure.) +@item no +This is an alias for @samp{single}. +@item posix +Generic POSIX/Unix98 thread support. +@item posix95 +Generic POSIX/Unix95 thread support. +@item rtems +RTEMS thread support. +@item single +Disable thread support, should work for all platforms. +@item solaris +Sun Solaris 2 thread support. +@item vxworks +VxWorks thread support. +@item win32 +Microsoft Win32 API thread support. +@item nks +Novell Kernel Services thread support. +@end table + +@item --enable-tls +Specify that the target supports TLS (Thread Local Storage). Usually +configure can correctly determine if TLS is supported. In cases where +it guesses incorrectly, TLS can be explicitly enabled or disabled with +@option{--enable-tls} or @option{--disable-tls}. This can happen if +the assembler supports TLS but the C library does not, or if the +assumptions made by the configure test are incorrect. + +@item --disable-tls +Specify that the target does not support TLS. +This is an alias for @option{--enable-tls=no}. + +@item --with-cpu=@var{cpu} +Specify which cpu variant the compiler should generate code for by default. +@var{cpu} will be used as the default value of the @option{-mcpu=} switch. +This option is only supported on some targets, including ARM, i386, PowerPC, +and SPARC@. + +@item --with-schedule=@var{cpu} +@itemx --with-arch=@var{cpu} +@itemx --with-tune=@var{cpu} +@itemx --with-abi=@var{abi} +@itemx --with-fpu=@var{type} +@itemx --with-float=@var{type} +These configure options provide default values for the @option{-mschedule=}, +@option{-march=}, @option{-mtune=}, @option{-mabi=}, and @option{-mfpu=} +options and for @option{-mhard-float} or @option{-msoft-float}. As with +@option{--with-cpu}, which switches will be accepted and acceptable values +of the arguments depend on the target. + +@item --with-mode=@var{mode} +Specify if the compiler should default to @option{-marm} or @option{-mthumb}. +This option is only supported on ARM targets. + +@item --with-divide=@var{type} +Specify how the compiler should generate code for checking for +division by zero. This option is only supported on the MIPS target. +The possibilities for @var{type} are: +@table @code +@item traps +Division by zero checks use conditional traps (this is the default on +systems that support conditional traps). +@item breaks +Division by zero checks use the break instruction. +@end table + +@item --enable-__cxa_atexit +Define if you want to use __cxa_atexit, rather than atexit, to +register C++ destructors for local statics and global objects. +This is essential for fully standards-compliant handling of +destructors, but requires __cxa_atexit in libc. This option is currently +only available on systems with GNU libc. When enabled, this will cause +@option{-fuse-cxa-exit} to be passed by default. + +@item --enable-target-optspace +Specify that target +libraries should be optimized for code space instead of code speed. +This is the default for the m32r platform. + +@item --disable-cpp +Specify that a user visible @command{cpp} program should not be installed. + +@item --with-cpp-install-dir=@var{dirname} +Specify that the user visible @command{cpp} program should be installed +in @file{@var{prefix}/@var{dirname}/cpp}, in addition to @var{bindir}. + +@item --enable-initfini-array +Force the use of sections @code{.init_array} and @code{.fini_array} +(instead of @code{.init} and @code{.fini}) for constructors and +destructors. Option @option{--disable-initfini-array} has the +opposite effect. If neither option is specified, the configure script +will try to guess whether the @code{.init_array} and +@code{.fini_array} sections are supported and, if they are, use them. + +@item --enable-maintainer-mode +The build rules that +regenerate the GCC master message catalog @file{gcc.pot} are normally +disabled. This is because it can only be rebuilt if the complete source +tree is present. If you have changed the sources and want to rebuild the +catalog, configuring with @option{--enable-maintainer-mode} will enable +this. Note that you need a recent version of the @code{gettext} tools +to do so. + +@item --disable-bootstrap +For a native build, the default configuration is to perform +a 3-stage bootstrap of the compiler when @samp{make} is invoked, +testing that GCC can compile itself correctly. If you want to disable +this process, you can configure with @option{--disable-bootstrap}. + +@item --enable-bootstrap +In special cases, you may want to perform a 3-stage build +even if the target and host triplets are different. +This could happen when the host can run code compiled for +the target (e.g.@: host is i686-linux, target is i486-linux). +Starting from GCC 4.2, to do this you have to configure explicitly +with @option{--enable-bootstrap}. + +@item --enable-generated-files-in-srcdir +Neither the .c and .h files that are generated from Bison and flex nor the +info manuals and man pages that are built from the .texi files are present +in the SVN development tree. When building GCC from that development tree, +or from one of our snapshots, those generated files are placed in your +build directory, which allows for the source to be in a readonly +directory. + +If you configure with @option{--enable-generated-files-in-srcdir} then those +generated files will go into the source directory. This is mainly intended +for generating release or prerelease tarballs of the GCC sources, since it +is not a requirement that the users of source releases to have flex, Bison, +or makeinfo. + +@item --enable-version-specific-runtime-libs +Specify +that runtime libraries should be installed in the compiler specific +subdirectory (@file{@var{libdir}/gcc}) rather than the usual places. In +addition, @samp{libstdc++}'s include files will be installed into +@file{@var{libdir}} unless you overruled it by using +@option{--with-gxx-include-dir=@var{dirname}}. Using this option is +particularly useful if you intend to use several versions of GCC in +parallel. This is currently supported by @samp{libgfortran}, +@samp{libjava}, @samp{libmudflap}, @samp{libstdc++}, and @samp{libobjc}. + +@item --with-java-home=@var{dirname} +This @samp{libjava} option overrides the default value of the +@samp{java.home} system property. It is also used to set +@samp{sun.boot.class.path} to @file{@var{dirname}/lib/rt.jar}. By +default @samp{java.home} is set to @file{@var{prefix}} and +@samp{sun.boot.class.path} to +@file{@var{datadir}/java/libgcj-@var{version}.jar}. + +@item --enable-languages=@var{lang1},@var{lang2},@dots{} +Specify that only a particular subset of compilers and +their runtime libraries should be built. For a list of valid values for +@var{langN} you can issue the following command in the +@file{gcc} directory of your GCC source tree:@* +@smallexample +grep language= */config-lang.in +@end smallexample +Currently, you can use any of the following: +@code{all}, @code{ada}, @code{c}, @code{c++}, @code{fortran}, @code{java}, +@code{objc}, @code{obj-c++}, @code{treelang}. +Building the Ada compiler has special requirements, see below. +If you do not pass this flag, or specify the option @code{all}, then all +default languages available in the @file{gcc} sub-tree will be configured. +Ada, Objective-C++, and treelang are not default languages; the rest are. +Re-defining @code{LANGUAGES} when calling @samp{make} @strong{does not} +work anymore, as those language sub-directories might not have been +configured! + +@item --disable-libada +Specify that the run-time libraries and tools used by GNAT should not +be built. This can be useful for debugging, or for compatibility with +previous Ada build procedures, when it was required to explicitly +do a @samp{make -C gcc gnatlib_and_tools}. + +@item --disable-libssp +Specify that the run-time libraries for stack smashing protection +should not be built. + +@item --disable-libgomp +Specify that the run-time libraries used by GOMP should not be built. + +@item --with-dwarf2 +Specify that the compiler should +use DWARF 2 debugging information as the default. + +@item --enable-targets=all +@itemx --enable-targets=@var{target_list} +Some GCC targets, e.g.@: powerpc64-linux, build bi-arch compilers. +These are compilers that are able to generate either 64-bit or 32-bit +code. Typically, the corresponding 32-bit target, e.g.@: +powerpc-linux for powerpc64-linux, only generates 32-bit code. This +option enables the 32-bit target to be a bi-arch compiler, which is +useful when you want a bi-arch compiler that defaults to 32-bit, and +you are building a bi-arch or multi-arch binutils in a combined tree. +Currently, this option only affects powerpc-linux. + +@item --enable-secureplt +This option enables @option{-msecure-plt} by default for powerpc-linux. +@ifnothtml +@xref{RS/6000 and PowerPC Options,, RS/6000 and PowerPC Options, gcc, +Using the GNU Compiler Collection (GCC)}, +@end ifnothtml +@ifhtml +See ``RS/6000 and PowerPC Options'' in the main manual +@end ifhtml + +@item --enable-win32-registry +@itemx --enable-win32-registry=@var{key} +@itemx --disable-win32-registry +The @option{--enable-win32-registry} option enables Microsoft Windows-hosted GCC +to look up installations paths in the registry using the following key: + +@smallexample +@code{HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\@var{key}} +@end smallexample + +@var{key} defaults to GCC version number, and can be overridden by the +@option{--enable-win32-registry=@var{key}} option. Vendors and distributors +who use custom installers are encouraged to provide a different key, +perhaps one comprised of vendor name and GCC version number, to +avoid conflict with existing installations. This feature is enabled +by default, and can be disabled by @option{--disable-win32-registry} +option. This option has no effect on the other hosts. + +@item --nfp +Specify that the machine does not have a floating point unit. This +option only applies to @samp{m68k-sun-sunos@var{n}}. On any other +system, @option{--nfp} has no effect. + +@item --enable-werror +@itemx --disable-werror +@itemx --enable-werror=yes +@itemx --enable-werror=no +When you specify this option, it controls whether certain files in the +compiler are built with @option{-Werror} in bootstrap stage2 and later. +If you don't specify it, @option{-Werror} is turned on for the main +development trunk. However it defaults to off for release branches and +final releases. The specific files which get @option{-Werror} are +controlled by the Makefiles. + +@item --enable-checking +@itemx --enable-checking=@var{list} +When you specify this option, the compiler is built to perform internal +consistency checks of the requested complexity. This does not change the +generated code, but adds error checking within the compiler. This will +slow down the compiler and may only work properly if you are building +the compiler with GCC@. This is @samp{yes} by default when building +from SVN or snapshots, but @samp{release} for releases. More control +over the checks may be had by specifying @var{list}. The categories of +checks available are @samp{yes} (most common checks +@samp{assert,misc,tree,gc,rtlflag,runtime}), @samp{no} (no checks at +all), @samp{all} (all but @samp{valgrind}), @samp{release} (cheapest +checks @samp{assert,runtime}) or @samp{none} (same as @samp{no}). +Individual checks can be enabled with these flags @samp{assert}, +@samp{fold}, @samp{gc}, @samp{gcac} @samp{misc}, @samp{rtl}, +@samp{rtlflag}, @samp{runtime}, @samp{tree}, and @samp{valgrind}. + +The @samp{valgrind} check requires the external @command{valgrind} +simulator, available from @uref{http://valgrind.org/}. The +@samp{rtl}, @samp{gcac} and @samp{valgrind} checks are very expensive. +To disable all checking, @samp{--disable-checking} or +@samp{--enable-checking=none} must be explicitly requested. Disabling +assertions will make the compiler and runtime slightly faster but +increase the risk of undetected internal errors causing wrong code to be +generated. + +@item --enable-coverage +@itemx --enable-coverage=@var{level} +With this option, the compiler is built to collect self coverage +information, every time it is run. This is for internal development +purposes, and only works when the compiler is being built with gcc. The +@var{level} argument controls whether the compiler is built optimized or +not, values are @samp{opt} and @samp{noopt}. For coverage analysis you +want to disable optimization, for performance analysis you want to +enable optimization. When coverage is enabled, the default level is +without optimization. + +@item --enable-gather-detailed-mem-stats +When this option is specified more detailed information on memory +allocation is gathered. This information is printed when using +@option{-fmem-report}. + +@item --with-gc +@itemx --with-gc=@var{choice} +With this option you can specify the garbage collector implementation +used during the compilation process. @var{choice} can be one of +@samp{page} and @samp{zone}, where @samp{page} is the default. + +@item --enable-nls +@itemx --disable-nls +The @option{--enable-nls} option enables Native Language Support (NLS), +which lets GCC output diagnostics in languages other than American +English. Native Language Support is enabled by default if not doing a +canadian cross build. The @option{--disable-nls} option disables NLS@. + +@item --with-included-gettext +If NLS is enabled, the @option{--with-included-gettext} option causes the build +procedure to prefer its copy of GNU @command{gettext}. + +@item --with-catgets +If NLS is enabled, and if the host lacks @code{gettext} but has the +inferior @code{catgets} interface, the GCC build procedure normally +ignores @code{catgets} and instead uses GCC's copy of the GNU +@code{gettext} library. The @option{--with-catgets} option causes the +build procedure to use the host's @code{catgets} in this situation. + +@item --with-libiconv-prefix=@var{dir} +Search for libiconv header files in @file{@var{dir}/include} and +libiconv library files in @file{@var{dir}/lib}. + +@item --enable-obsolete +Enable configuration for an obsoleted system. If you attempt to +configure GCC for a system (build, host, or target) which has been +obsoleted, and you do not specify this flag, configure will halt with an +error message. + +All support for systems which have been obsoleted in one release of GCC +is removed entirely in the next major release, unless someone steps +forward to maintain the port. + +@item --enable-decimal-float +@itemx --disable-decimal-float +Enable (or disable) support for the C decimal floating point +extension. This is enabled by default only on PowerPC GNU/Linux +systems. Other systems may also support it, but require the user to +specifically enable it. + +@item --with-long-double-128 +Specify if @code{long double} type should be 128-bit by default on selected +GNU/Linux architectures. If using @code{--without-long-double-128}, +@code{long double} will be by default 64-bit, the same as @code{double} type. +When neither of these configure options are used, the default will be +128-bit @code{long double} when built against GNU C Library 2.4 and later, +64-bit @code{long double} otherwise. + +@end table + +@subheading Cross-Compiler-Specific Options +The following options only apply to building cross compilers. +@table @code +@item --with-sysroot +@itemx --with-sysroot=@var{dir} +Tells GCC to consider @var{dir} as the root of a tree that contains a +(subset of) the root filesystem of the target operating system. +Target system headers, libraries and run-time object files will be +searched in there. The specified directory is not copied into the +install tree, unlike the options @option{--with-headers} and +@option{--with-libs} that this option obsoletes. The default value, +in case @option{--with-sysroot} is not given an argument, is +@option{$@{gcc_tooldir@}/sys-root}. If the specified directory is a +subdirectory of @option{$@{exec_prefix@}}, then it will be found relative to +the GCC binaries if the installation tree is moved. + +@item --with-build-sysroot +@itemx --with-build-sysroot=@var{dir} +Tells GCC to consider @var{dir} as the system root (see +@option{--with-sysroot}) while building target libraries, instead of +the directory specified with @option{--with-sysroot}. This option is +only useful when you are already using @option{--with-sysroot}. You +can use @option{--with-build-sysroot} when you are configuring with +@option{--prefix} set to a directory that is different from the one in +which you are installing GCC and your target libraries. + +This option affects the system root for the compiler used to build +target libraries (which runs on the build system); it does not affect +the compiler which is used to build GCC itself. + +@item --with-headers +@itemx --with-headers=@var{dir} +Deprecated in favor of @option{--with-sysroot}. +Specifies that target headers are available when building a cross compiler. +The @var{dir} argument specifies a directory which has the target include +files. These include files will be copied into the @file{gcc} install +directory. @emph{This option with the @var{dir} argument is required} when +building a cross compiler, if @file{@var{prefix}/@var{target}/sys-include} +doesn't pre-exist. If @file{@var{prefix}/@var{target}/sys-include} does +pre-exist, the @var{dir} argument may be omitted. @command{fixincludes} +will be run on these files to make them compatible with GCC@. + +@item --without-headers +Tells GCC not use any target headers from a libc when building a cross +compiler. When crossing to GNU/Linux, you need the headers so GCC +can build the exception handling for libgcc. + +@item --with-libs +@itemx --with-libs=``@var{dir1} @var{dir2} @dots{} @var{dirN}'' +Deprecated in favor of @option{--with-sysroot}. +Specifies a list of directories which contain the target runtime +libraries. These libraries will be copied into the @file{gcc} install +directory. If the directory list is omitted, this option has no +effect. + +@item --with-newlib +Specifies that @samp{newlib} is +being used as the target C library. This causes @code{__eprintf} to be +omitted from @file{libgcc.a} on the assumption that it will be provided by +@samp{newlib}. + +@item --with-build-time-tools=@var{dir} +Specifies where to find the set of target tools (assembler, linker, etc.) +that will be used while building GCC itself. This option can be useful +if the directory layouts are different between the system you are building +GCC on, and the system where you will deploy it. + +For example, on a @option{ia64-hp-hpux} system, you may have the GNU +assembler and linker in @file{/usr/bin}, and the native tools in a +different path, and build a toolchain that expects to find the +native tools in @file{/usr/bin}. + +When you use this option, you should ensure that @var{dir} includes +@command{ar}, @command{as}, @command{ld}, @command{nm}, +@command{ranlib} and @command{strip} if necessary, and possibly +@command{objdump}. Otherwise, GCC may use an inconsistent set of +tools. +@end table + +@subheading Fortran-Specific Options + +The following options apply to the build of the Fortran front end. + +@table @code + +@item --with-gmp=@var{pathname} +@itemx --with-gmp-include=@var{pathname} +@itemx --with-gmp-lib=@var{pathname} +@itemx --with-mpfr=@var{pathname} +@itemx --with-mpfr-include=@var{pathname} +@itemx --with-mpfr-lib=@var{pathname} +If you do not have GMP (the GNU Multiple Precision library) and the +MPFR Libraries installed in a standard location and you want to build +the Fortran front-end, you can explicitly specify the directory where +they are installed (@samp{--with-gmp=@var{gmpinstalldir}}, +@samp{--with-mpfr=@var{mpfrinstalldir}}). The +@option{--with-gmp=@var{gmpinstalldir}} option is shorthand for +@option{--with-gmp-lib=@var{gmpinstalldir}/lib} and +@option{--with-gmp-include=@var{gmpinstalldir}/include}. Likewise the +@option{--with-mpfr=@var{mpfrinstalldir}} option is shorthand for +@option{--with-mpfr-lib=@var{mpfrinstalldir}/lib} and +@option{--with-mpfr-include=@var{mpfrinstalldir}/include}. If these +shorthand assumptions are not correct, you can use the explicit +include and lib options directly. + +@end table + +@subheading Java-Specific Options + +The following option applies to the build of the Java front end. + +@table @code +@item --disable-libgcj +Specify that the run-time libraries +used by GCJ should not be built. This is useful in case you intend +to use GCJ with some other run-time, or you're going to install it +separately, or it just happens not to build on your particular +machine. In general, if the Java front end is enabled, the GCJ +libraries will be enabled too, unless they're known to not work on +the target platform. If GCJ is enabled but @samp{libgcj} isn't built, you +may need to port it; in this case, before modifying the top-level +@file{configure.in} so that @samp{libgcj} is enabled by default on this platform, +you may use @option{--enable-libgcj} to override the default. + +@end table + +The following options apply to building @samp{libgcj}. + +@subsubheading General Options + +@table @code +@item --disable-getenv-properties +Don't set system properties from @env{GCJ_PROPERTIES}. + +@item --enable-hash-synchronization +Use a global hash table for monitor locks. Ordinarily, +@samp{libgcj}'s @samp{configure} script automatically makes +the correct choice for this option for your platform. Only use +this if you know you need the library to be configured differently. + +@item --enable-interpreter +Enable the Java interpreter. The interpreter is automatically +enabled by default on all platforms that support it. This option +is really only useful if you want to disable the interpreter +(using @option{--disable-interpreter}). + +@item --disable-java-net +Disable java.net. This disables the native part of java.net only, +using non-functional stubs for native method implementations. + +@item --disable-jvmpi +Disable JVMPI support. + +@item --with-ecos +Enable runtime eCos target support. + +@item --without-libffi +Don't use @samp{libffi}. This will disable the interpreter and JNI +support as well, as these require @samp{libffi} to work. + +@item --enable-libgcj-debug +Enable runtime debugging code. + +@item --enable-libgcj-multifile +If specified, causes all @file{.java} source files to be +compiled into @file{.class} files in one invocation of +@samp{gcj}. This can speed up build time, but is more +resource-intensive. If this option is unspecified or +disabled, @samp{gcj} is invoked once for each @file{.java} +file to compile into a @file{.class} file. + +@item --with-libiconv-prefix=DIR +Search for libiconv in @file{DIR/include} and @file{DIR/lib}. + +@item --enable-sjlj-exceptions +Force use of the @code{setjmp}/@code{longjmp}-based scheme for exceptions. +@samp{configure} ordinarily picks the correct value based on the platform. +Only use this option if you are sure you need a different setting. + +@item --with-system-zlib +Use installed @samp{zlib} rather than that included with GCC@. + +@item --with-win32-nlsapi=ansi, unicows or unicode +Indicates how MinGW @samp{libgcj} translates between UNICODE +characters and the Win32 API@. +@table @code +@item ansi +Use the single-byte @code{char} and the Win32 A functions natively, +translating to and from UNICODE when using these functions. If +unspecified, this is the default. + +@item unicows +Use the @code{WCHAR} and Win32 W functions natively. Adds +@code{-lunicows} to @file{libgcj.spec} to link with @samp{libunicows}. +@file{unicows.dll} needs to be deployed on Microsoft Windows 9X machines +running built executables. @file{libunicows.a}, an open-source +import library around Microsoft's @code{unicows.dll}, is obtained from +@uref{http://libunicows.sourceforge.net/}, which also gives details +on getting @file{unicows.dll} from Microsoft. + +@item unicode +Use the @code{WCHAR} and Win32 W functions natively. Does @emph{not} +add @code{-lunicows} to @file{libgcj.spec}. The built executables will +only run on Microsoft Windows NT and above. +@end table +@end table + +@subsubheading AWT-Specific Options + +@table @code +@item --with-x +Use the X Window System. + +@item --enable-java-awt=PEER(S) +Specifies the AWT peer library or libraries to build alongside +@samp{libgcj}. If this option is unspecified or disabled, AWT +will be non-functional. Current valid values are @option{gtk} and +@option{xlib}. Multiple libraries should be separated by a +comma (i.e.@: @option{--enable-java-awt=gtk,xlib}). + +@item --enable-gtk-cairo +Build the cairo Graphics2D implementation on GTK@. + +@item --enable-java-gc=TYPE +Choose garbage collector. Defaults to @option{boehm} if unspecified. + +@item --disable-gtktest +Do not try to compile and run a test GTK+ program. + +@item --disable-glibtest +Do not try to compile and run a test GLIB program. + +@item --with-libart-prefix=PFX +Prefix where libart is installed (optional). + +@item --with-libart-exec-prefix=PFX +Exec prefix where libart is installed (optional). + +@item --disable-libarttest +Do not try to compile and run a test libart program. + +@end table + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Building**************************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Building, Testing, Configuration, Installing GCC +@end ifnothtml +@ifset buildhtml +@ifnothtml +@chapter Building +@end ifnothtml +@cindex Installing GCC: Building + +Now that GCC is configured, you are ready to build the compiler and +runtime libraries. + +Some commands executed when making the compiler may fail (return a +nonzero status) and be ignored by @command{make}. These failures, which +are often due to files that were not found, are expected, and can safely +be ignored. + +It is normal to have compiler warnings when compiling certain files. +Unless you are a GCC developer, you can generally ignore these warnings +unless they cause compilation to fail. Developers should attempt to fix +any warnings encountered, however they can temporarily continue past +warnings-as-errors by specifying the configure flag +@option{--disable-werror}. + +On certain old systems, defining certain environment variables such as +@env{CC} can interfere with the functioning of @command{make}. + +If you encounter seemingly strange errors when trying to build the +compiler in a directory other than the source directory, it could be +because you have previously configured the compiler in the source +directory. Make sure you have done all the necessary preparations. + +If you build GCC on a BSD system using a directory stored in an old System +V file system, problems may occur in running @command{fixincludes} if the +System V file system doesn't support symbolic links. These problems +result in a failure to fix the declaration of @code{size_t} in +@file{sys/types.h}. If you find that @code{size_t} is a signed type and +that type mismatches occur, this could be the cause. + +The solution is not to use such a directory for building GCC@. + +When building from SVN or snapshots, or if you modify parser sources, +you need the Bison parser generator installed. If you do not modify +parser sources, releases contain the Bison-generated files and you do +not need Bison installed to build them. + +When building from SVN or snapshots, or if you modify Texinfo +documentation, you need version 4.4 or later of Texinfo installed if you +want Info documentation to be regenerated. Releases contain Info +documentation pre-built for the unmodified documentation in the release. + +@section Building a native compiler + +For a native build, the default configuration is to perform +a 3-stage bootstrap of the compiler when @samp{make} is invoked. +This will build the entire GCC system and ensure that it compiles +itself correctly. It can be disabled with the @option{--disable-bootstrap} +parameter to @samp{configure}, but bootstrapping is suggested because +the compiler will be tested more completely and could also have +better performance. + +The bootstrapping process will complete the following steps: + +@itemize @bullet +@item +Build tools necessary to build the compiler. + +@item +Perform a 3-stage bootstrap of the compiler. This includes building +three times the target tools for use by the compiler such as binutils +(bfd, binutils, gas, gprof, ld, and opcodes) if they have been +individually linked or moved into the top level GCC source tree before +configuring. + +@item +Perform a comparison test of the stage2 and stage3 compilers. + +@item +Build runtime libraries using the stage3 compiler from the previous step. + +@end itemize + +If you are short on disk space you might consider @samp{make +bootstrap-lean} instead. The sequence of compilation is the +same described above, but object files from the stage1 and +stage2 of the 3-stage bootstrap of the compiler are deleted as +soon as they are no longer needed. + +If you want to save additional space during the bootstrap and in +the final installation as well, you can build the compiler binaries +without debugging information as in the following example. This will save +roughly 40% of disk space both for the bootstrap and the final installation. +(Libraries will still contain debugging information.) + +@smallexample + make CFLAGS='-O' LIBCFLAGS='-g -O2' \ + LIBCXXFLAGS='-g -O2 -fno-implicit-templates' bootstrap +@end smallexample + +If you wish to use non-default GCC flags when compiling the stage2 and +stage3 compilers, set @code{BOOT_CFLAGS} on the command line when doing +@samp{make}. Non-default optimization flags are less well +tested here than the default of @samp{-g -O2}, but should still work. +In a few cases, you may find that you need to specify special flags such +as @option{-msoft-float} here to complete the bootstrap; or, if the +native compiler miscompiles the stage1 compiler, you may need to work +around this, by choosing @code{BOOT_CFLAGS} to avoid the parts of the +stage1 compiler that were miscompiled, or by using @samp{make +bootstrap4} to increase the number of stages of bootstrap. + +Note that using non-standard @code{CFLAGS} can cause bootstrap to fail +if these trigger a warning with the new compiler. For example using +@samp{-O2 -g -mcpu=i686} on @code{i686-pc-linux-gnu} will cause bootstrap +failure as @option{-mcpu=} is deprecated in 3.4.0 and above. + + +If you used the flag @option{--enable-languages=@dots{}} to restrict +the compilers to be built, only those you've actually enabled will be +built. This will of course only build those runtime libraries, for +which the particular compiler has been built. Please note, +that re-defining @env{LANGUAGES} when calling @samp{make} +@strong{does not} work anymore! + +If the comparison of stage2 and stage3 fails, this normally indicates +that the stage2 compiler has compiled GCC incorrectly, and is therefore +a potentially serious bug which you should investigate and report. (On +a few systems, meaningful comparison of object files is impossible; they +always appear ``different''. If you encounter this problem, you will +need to disable comparison in the @file{Makefile}.) + +If you do not want to bootstrap your compiler, you can configure with +@option{--disable-bootstrap}. In particular cases, you may want to +bootstrap your compiler even if the target system is not the same as +the one you are building on: for example, you could build a +@code{powerpc-unknown-linux-gnu} toolchain on a +@code{powerpc64-unknown-linux-gnu} host. In this case, pass +@option{--enable-bootstrap} to the configure script. + + +@section Building a cross compiler + +When building a cross compiler, it is not generally possible to do a +3-stage bootstrap of the compiler. This makes for an interesting problem +as parts of GCC can only be built with GCC@. + +To build a cross compiler, we first recommend building and installing a +native compiler. You can then use the native GCC compiler to build the +cross compiler. The installed native compiler needs to be GCC version +2.95 or later. + +Assuming you have already installed a native copy of GCC and configured +your cross compiler, issue the command @command{make}, which performs the +following steps: + +@itemize @bullet +@item +Build host tools necessary to build the compiler. + +@item +Build target tools for use by the compiler such as binutils (bfd, +binutils, gas, gprof, ld, and opcodes) +if they have been individually linked or moved into the top level GCC source +tree before configuring. + +@item +Build the compiler (single stage only). + +@item +Build runtime libraries using the compiler from the previous step. +@end itemize + +Note that if an error occurs in any step the make process will exit. + +If you are not building GNU binutils in the same source tree as GCC, +you will need a cross-assembler and cross-linker installed before +configuring GCC@. Put them in the directory +@file{@var{prefix}/@var{target}/bin}. Here is a table of the tools +you should put in this directory: + +@table @file +@item as +This should be the cross-assembler. + +@item ld +This should be the cross-linker. + +@item ar +This should be the cross-archiver: a program which can manipulate +archive files (linker libraries) in the target machine's format. + +@item ranlib +This should be a program to construct a symbol table in an archive file. +@end table + +The installation of GCC will find these programs in that directory, +and copy or link them to the proper place to for the cross-compiler to +find them when run later. + +The easiest way to provide these files is to build the Binutils package. +Configure it with the same @option{--host} and @option{--target} +options that you use for configuring GCC, then build and install +them. They install their executables automatically into the proper +directory. Alas, they do not support all the targets that GCC +supports. + +If you are not building a C library in the same source tree as GCC, +you should also provide the target libraries and headers before +configuring GCC, specifying the directories with +@option{--with-sysroot} or @option{--with-headers} and +@option{--with-libs}. Many targets also require ``start files'' such +as @file{crt0.o} and +@file{crtn.o} which are linked into each executable. There may be several +alternatives for @file{crt0.o}, for use with profiling or other +compilation options. Check your target's definition of +@code{STARTFILE_SPEC} to find out what start files it uses. + +@section Building in parallel + +GNU Make 3.79 and above, which is necessary to build GCC, support +building in parallel. To activate this, you can use @samp{make -j 2} +instead of @samp{make}. You can also specify a bigger number, and +in most cases using a value greater than the number of processors in +your machine will result in fewer and shorter I/O latency hits, thus +improving overall throughput; this is especially true for slow drives +and network filesystems. + +@section Building the Ada compiler + +In order to build GNAT, the Ada compiler, you need a working GNAT +compiler (GNAT version 3.14 or later, or GCC version 3.1 or later). +This includes GNAT tools such as @command{gnatmake} and +@command{gnatlink}, since the Ada front end is written in Ada and +uses some GNAT-specific extensions. + +In order to build a cross compiler, it is suggested to install +the new compiler as native first, and then use it to build the cross +compiler. + +@command{configure} does not test whether the GNAT installation works +and has a sufficiently recent version; if too old a GNAT version is +installed, the build will fail unless @option{--enable-languages} is +used to disable building the Ada front end. + +@section Building with profile feedback + +It is possible to use profile feedback to optimize the compiler itself. This +should result in a faster compiler binary. Experiments done on x86 using gcc +3.3 showed approximately 7 percent speedup on compiling C programs. To +bootstrap the compiler with profile feedback, use @code{make profiledbootstrap}. + +When @samp{make profiledbootstrap} is run, it will first build a @code{stage1} +compiler. This compiler is used to build a @code{stageprofile} compiler +instrumented to collect execution counts of instruction and branch +probabilities. Then runtime libraries are compiled with profile collected. +Finally a @code{stagefeedback} compiler is built using the information collected. + +Unlike standard bootstrap, several additional restrictions apply. The +compiler used to build @code{stage1} needs to support a 64-bit integral type. +It is recommended to only use GCC for this. Also parallel make is currently +not supported since collisions in profile collecting may occur. + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Testing***************************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Testing, Final install, Building, Installing GCC +@end ifnothtml +@ifset testhtml +@ifnothtml +@chapter Installing GCC: Testing +@end ifnothtml +@cindex Testing +@cindex Installing GCC: Testing +@cindex Testsuite + +Before you install GCC, we encourage you to run the testsuites and to +compare your results with results from a similar configuration that have +been submitted to the +@uref{http://gcc.gnu.org/ml/gcc-testresults/,,gcc-testresults mailing list}. +Some of these archived results are linked from the build status lists +at @uref{http://gcc.gnu.org/buildstat.html}, although not everyone who +reports a successful build runs the testsuites and submits the results. +This step is optional and may require you to download additional software, +but it can give you confidence in your new GCC installation or point out +problems before you install and start using your new GCC@. + +First, you must have @uref{download.html,,downloaded the testsuites}. +These are part of the full distribution, but if you downloaded the +``core'' compiler plus any front ends, you must download the testsuites +separately. + +Second, you must have the testing tools installed. This includes +@uref{http://www.gnu.org/software/dejagnu/,,DejaGnu}, Tcl, and Expect; +the DejaGnu site has links to these. + +If the directories where @command{runtest} and @command{expect} were +installed are not in the @env{PATH}, you may need to set the following +environment variables appropriately, as in the following example (which +assumes that DejaGnu has been installed under @file{/usr/local}): + +@smallexample + TCL_LIBRARY = /usr/local/share/tcl8.0 + DEJAGNULIBS = /usr/local/share/dejagnu +@end smallexample + +(On systems such as Cygwin, these paths are required to be actual +paths, not mounts or links; presumably this is due to some lack of +portability in the DejaGnu code.) + + +Finally, you can run the testsuite (which may take a long time): +@smallexample + cd @var{objdir}; make -k check +@end smallexample + +This will test various components of GCC, such as compiler +front ends and runtime libraries. While running the testsuite, DejaGnu +might emit some harmless messages resembling +@samp{WARNING: Couldn't find the global config file.} or +@samp{WARNING: Couldn't find tool init file} that can be ignored. + +@section How can you run the testsuite on selected tests? + +In order to run sets of tests selectively, there are targets +@samp{make check-gcc} and @samp{make check-g++} +in the @file{gcc} subdirectory of the object directory. You can also +just run @samp{make check} in a subdirectory of the object directory. + + +A more selective way to just run all @command{gcc} execute tests in the +testsuite is to use + +@smallexample + make check-gcc RUNTESTFLAGS="execute.exp @var{other-options}" +@end smallexample + +Likewise, in order to run only the @command{g++} ``old-deja'' tests in +the testsuite with filenames matching @samp{9805*}, you would use + +@smallexample + make check-g++ RUNTESTFLAGS="old-deja.exp=9805* @var{other-options}" +@end smallexample + +The @file{*.exp} files are located in the testsuite directories of the GCC +source, the most important ones being @file{compile.exp}, +@file{execute.exp}, @file{dg.exp} and @file{old-deja.exp}. +To get a list of the possible @file{*.exp} files, pipe the +output of @samp{make check} into a file and look at the +@samp{Running @dots{} .exp} lines. + +@section Passing options and running multiple testsuites + +You can pass multiple options to the testsuite using the +@samp{--target_board} option of DejaGNU, either passed as part of +@samp{RUNTESTFLAGS}, or directly to @command{runtest} if you prefer to +work outside the makefiles. For example, + +@smallexample + make check-g++ RUNTESTFLAGS="--target_board=unix/-O3/-fno-strength-reduce" +@end smallexample + +will run the standard @command{g++} testsuites (``unix'' is the target name +for a standard native testsuite situation), passing +@samp{-O3 -fno-strength-reduce} to the compiler on every test, i.e., +slashes separate options. + +You can run the testsuites multiple times using combinations of options +with a syntax similar to the brace expansion of popular shells: + +@smallexample + @dots{}"--target_board=arm-sim/@{-mhard-float,-msoft-float@}@{-O1,-O2,-O3,@}" +@end smallexample + +(Note the empty option caused by the trailing comma in the final group.) +The following will run each testsuite eight times using the @samp{arm-sim} +target, as if you had specified all possible combinations yourself: + +@smallexample + --target_board=arm-sim/-mhard-float/-O1 + --target_board=arm-sim/-mhard-float/-O2 + --target_board=arm-sim/-mhard-float/-O3 + --target_board=arm-sim/-mhard-float + --target_board=arm-sim/-msoft-float/-O1 + --target_board=arm-sim/-msoft-float/-O2 + --target_board=arm-sim/-msoft-float/-O3 + --target_board=arm-sim/-msoft-float +@end smallexample + +They can be combined as many times as you wish, in arbitrary ways. This +list: + +@smallexample + @dots{}"--target_board=unix/-Wextra@{-O3,-fno-strength-reduce@}@{-fomit-frame-pointer,@}" +@end smallexample + +will generate four combinations, all involving @samp{-Wextra}. + +The disadvantage to this method is that the testsuites are run in serial, +which is a waste on multiprocessor systems. For users with GNU Make and +a shell which performs brace expansion, you can run the testsuites in +parallel by having the shell perform the combinations and @command{make} +do the parallel runs. Instead of using @samp{--target_board}, use a +special makefile target: + +@smallexample + make -j@var{N} check-@var{testsuite}//@var{test-target}/@var{option1}/@var{option2}/@dots{} +@end smallexample + +For example, + +@smallexample + make -j3 check-gcc//sh-hms-sim/@{-m1,-m2,-m3,-m3e,-m4@}/@{,-nofpu@} +@end smallexample + +will run three concurrent ``make-gcc'' testsuites, eventually testing all +ten combinations as described above. Note that this is currently only +supported in the @file{gcc} subdirectory. (To see how this works, try +typing @command{echo} before the example given here.) + + +@section Additional testing for Java Class Libraries + +The Java runtime tests can be executed via @samp{make check} +in the @file{@var{target}/libjava/testsuite} directory in +the build tree. + +The @uref{http://sourceware.org/mauve/,,Mauve Project} provides +a suite of tests for the Java Class Libraries. This suite can be run +as part of libgcj testing by placing the Mauve tree within the libjava +testsuite at @file{libjava/testsuite/libjava.mauve/mauve}, or by +specifying the location of that tree when invoking @samp{make}, as in +@samp{make MAUVEDIR=~/mauve check}. + +@uref{http://sourceware.org/mauve/jacks.html,,Jacks} +is a free testsuite that tests Java compiler front ends. This suite +can be run as part of libgcj testing by placing the Jacks tree within +the libjava testsuite at @file{libjava/testsuite/libjava.jacks/jacks}. + +@section How to interpret test results + +The result of running the testsuite are various @file{*.sum} and @file{*.log} +files in the testsuite subdirectories. The @file{*.log} files contain a +detailed log of the compiler invocations and the corresponding +results, the @file{*.sum} files summarize the results. These summaries +contain status codes for all tests: + +@itemize @bullet +@item +PASS: the test passed as expected +@item +XPASS: the test unexpectedly passed +@item +FAIL: the test unexpectedly failed +@item +XFAIL: the test failed as expected +@item +UNSUPPORTED: the test is not supported on this platform +@item +ERROR: the testsuite detected an error +@item +WARNING: the testsuite detected a possible problem +@end itemize + +It is normal for some tests to report unexpected failures. At the +current time the testing harness does not allow fine grained control +over whether or not a test is expected to fail. This problem should +be fixed in future releases. + + +@section Submitting test results + +If you want to report the results to the GCC project, use the +@file{contrib/test_summary} shell script. Start it in the @var{objdir} with + +@smallexample + @var{srcdir}/contrib/test_summary -p your_commentary.txt \ + -m gcc-testresults@@gcc.gnu.org |sh +@end smallexample + +This script uses the @command{Mail} program to send the results, so +make sure it is in your @env{PATH}. The file @file{your_commentary.txt} is +prepended to the testsuite summary and should contain any special +remarks you have on your results or your build environment. Please +do not edit the testsuite result block or the subject line, as these +messages may be automatically processed. + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Final install*********************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Final install, , Testing, Installing GCC +@end ifnothtml +@ifset finalinstallhtml +@ifnothtml +@chapter Installing GCC: Final installation +@end ifnothtml + +Now that GCC has been built (and optionally tested), you can install it with +@smallexample +cd @var{objdir}; make install +@end smallexample + +We strongly recommend to install into a target directory where there is +no previous version of GCC present. + +That step completes the installation of GCC; user level binaries can +be found in @file{@var{prefix}/bin} where @var{prefix} is the value +you specified with the @option{--prefix} to configure (or +@file{/usr/local} by default). (If you specified @option{--bindir}, +that directory will be used instead; otherwise, if you specified +@option{--exec-prefix}, @file{@var{exec-prefix}/bin} will be used.) +Headers for the C++ and Java libraries are installed in +@file{@var{prefix}/include}; libraries in @file{@var{libdir}} +(normally @file{@var{prefix}/lib}); internal parts of the compiler in +@file{@var{libdir}/gcc} and @file{@var{libexecdir}/gcc}; documentation +in info format in @file{@var{infodir}} (normally +@file{@var{prefix}/info}). + +When installing cross-compilers, GCC's executables +are not only installed into @file{@var{bindir}}, that +is, @file{@var{exec-prefix}/bin}, but additionally into +@file{@var{exec-prefix}/@var{target-alias}/bin}, if that directory +exists. Typically, such @dfn{tooldirs} hold target-specific +binutils, including assembler and linker. + +Installation into a temporary staging area or into a @command{chroot} +jail can be achieved with the command + +@smallexample +make DESTDIR=@var{path-to-rootdir} install +@end smallexample + +@noindent where @var{path-to-rootdir} is the absolute path of +a directory relative to which all installation paths will be +interpreted. Note that the directory specified by @code{DESTDIR} +need not exist yet; it will be created if necessary. + +There is a subtle point with tooldirs and @code{DESTDIR}: +If you relocate a cross-compiler installation with +e.g.@: @samp{DESTDIR=@var{rootdir}}, then the directory +@file{@var{rootdir}/@var{exec-prefix}/@var{target-alias}/bin} will +be filled with duplicated GCC executables only if it already exists, +it will not be created otherwise. This is regarded as a feature, +not as a bug, because it gives slightly more control to the packagers +using the @code{DESTDIR} feature. + +If you are bootstrapping a released version of GCC then please +quickly review the build status page for your release, available from +@uref{http://gcc.gnu.org/buildstat.html}. +If your system is not listed for the version of GCC that you built, +send a note to +@email{gcc@@gcc.gnu.org} indicating +that you successfully built and installed GCC@. +Include the following information: + +@itemize @bullet +@item +Output from running @file{@var{srcdir}/config.guess}. Do not send +that file itself, just the one-line output from running it. + +@item +The output of @samp{gcc -v} for your newly installed @command{gcc}. +This tells us which version of GCC you built and the options you passed to +configure. + +@item +Whether you enabled all languages or a subset of them. If you used a +full distribution then this information is part of the configure +options in the output of @samp{gcc -v}, but if you downloaded the +``core'' compiler plus additional front ends then it isn't apparent +which ones you built unless you tell us about it. + +@item +If the build was for GNU/Linux, also include: +@itemize @bullet +@item +The distribution name and version (e.g., Red Hat 7.1 or Debian 2.2.3); +this information should be available from @file{/etc/issue}. + +@item +The version of the Linux kernel, available from @samp{uname --version} +or @samp{uname -a}. + +@item +The version of glibc you used; for RPM-based systems like Red Hat, +Mandrake, and SuSE type @samp{rpm -q glibc} to get the glibc version, +and on systems like Debian and Progeny use @samp{dpkg -l libc6}. +@end itemize +For other systems, you can include similar information if you think it is +relevant. + +@item +Any other information that you think would be useful to people building +GCC on the same configuration. The new entry in the build status list +will include a link to the archived copy of your message. +@end itemize + +We'd also like to know if the +@ifnothtml +@ref{Specific, host/target specific installation notes} +@end ifnothtml +@ifhtml +@uref{specific.html,,host/target specific installation notes} +@end ifhtml +didn't include your host/target information or if that information is +incomplete or out of date. Send a note to +@email{gcc@@gcc.gnu.org} detailing how the information should be changed. + +If you find a bug, please report it following the +@uref{../bugs.html,,bug reporting guidelines}. + +If you want to print the GCC manuals, do @samp{cd @var{objdir}; make +dvi}. You will need to have @command{texi2dvi} (version at least 4.4) +and @TeX{} installed. This creates a number of @file{.dvi} files in +subdirectories of @file{@var{objdir}}; these may be converted for +printing with programs such as @command{dvips}. Alternately, by using +@samp{make pdf} in place of @samp{make dvi}, you can create documentation +in the form of @file{.pdf} files; this requires @command{texi2pdf}, which +is included with Texinfo version 4.8 and later. You can also +@uref{http://www.gnu.org/order/order.html,,buy printed manuals from the +Free Software Foundation}, though such manuals may not be for the most +recent version of GCC@. + +If you would like to generate online HTML documentation, do @samp{cd +@var{objdir}; make html} and HTML will be generated for the gcc manuals in +@file{@var{objdir}/gcc/HTML}. + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Binaries**************************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Binaries, Specific, Installing GCC, Top +@end ifnothtml +@ifset binarieshtml +@ifnothtml +@chapter Installing GCC: Binaries +@end ifnothtml +@cindex Binaries +@cindex Installing GCC: Binaries + +We are often asked about pre-compiled versions of GCC@. While we cannot +provide these for all platforms, below you'll find links to binaries for +various platforms where creating them by yourself is not easy due to various +reasons. + +Please note that we did not create these binaries, nor do we +support them. If you have any problems installing them, please +contact their makers. + +@itemize +@item +AIX: +@itemize +@item +@uref{http://www.bullfreeware.com,,Bull's Freeware and Shareware Archive for AIX}; + +@item +@uref{http://aixpdslib.seas.ucla.edu,,UCLA Software Library for AIX}. +@end itemize + +@item +DOS---@uref{http://www.delorie.com/djgpp/,,DJGPP}. + +@item +Renesas H8/300[HS]---@uref{http://h8300-hms.sourceforge.net/,,GNU +Development Tools for the Renesas H8/300[HS] Series}. + +@item +HP-UX: +@itemize +@item +@uref{http://hpux.cs.utah.edu/,,HP-UX Porting Center}; + +@item +@uref{ftp://sunsite.informatik.rwth-aachen.de/pub/packages/gcc_hpux/,,Binaries for HP-UX 11.00 at Aachen University of Technology}. +@end itemize + +@item +Motorola 68HC11/68HC12---@uref{http://www.gnu-m68hc11.org,,GNU +Development Tools for the Motorola 68HC11/68HC12}. + +@item +@uref{http://www.sco.com/skunkware/devtools/index.html#gcc,,SCO +OpenServer/Unixware}. + +@item +Solaris 2 (SPARC, Intel)---@uref{http://www.sunfreeware.com/,,Sunfreeware}. + +@item +SGI---@uref{http://freeware.sgi.com/,,SGI Freeware}. + +@item +Microsoft Windows: +@itemize +@item +The @uref{http://sourceware.org/cygwin/,,Cygwin} project; +@item +The @uref{http://www.mingw.org/,,MinGW} project. +@end itemize + +@item +@uref{ftp://ftp.thewrittenword.com/packages/by-name/,,The +Written Word} offers binaries for +AIX 4.3.2. +IRIX 6.5, +Digital UNIX 4.0D and 5.1, +GNU/Linux (i386), +HP-UX 10.20, 11.00, and 11.11, and +Solaris/SPARC 2.5.1, 2.6, 7, 8, and 9. + +@item +@uref{http://www.openpkg.org/,,OpenPKG} offers binaries for quite a +number of platforms. + +@item +The @uref{http://gcc.gnu.org/wiki/GFortranBinaries,,GFortran Wiki} has +links to GNU Fortran binaries for several platforms. +@end itemize + +In addition to those specific offerings, you can get a binary +distribution CD-ROM from the +@uref{http://www.gnu.org/order/order.html,,Free Software Foundation}. +It contains binaries for a number of platforms, and +includes not only GCC, but other stuff as well. The current CD does +not contain the latest version of GCC, but it should allow +bootstrapping the compiler. An updated version of that disk is in the +works. + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Specific**************************************************************** +@ifnothtml +@comment node-name, next, previous, up +@node Specific, Old, Binaries, Top +@end ifnothtml +@ifset specifichtml +@ifnothtml +@chapter Host/target specific installation notes for GCC +@end ifnothtml +@cindex Specific +@cindex Specific installation notes +@cindex Target specific installation +@cindex Host specific installation +@cindex Target specific installation notes + +Please read this document carefully @emph{before} installing the +GNU Compiler Collection on your machine. + +Note that this list of install notes is @emph{not} a list of supported +hosts or targets. Not all supported hosts and targets are listed +here, only the ones that require host-specific or target-specific +information are. + +@ifhtml +@itemize +@item +@uref{#alpha-x-x,,alpha*-*-*} +@item +@uref{#alpha-dec-osf,,alpha*-dec-osf*} +@item +@uref{#alphaev5-cray-unicosmk,,alphaev5-cray-unicosmk*} +@item +@uref{#arc-x-elf,,arc-*-elf} +@item +@uref{#arm-x-elf,,arm-*-elf} +@uref{#arm-x-coff,,arm-*-coff} +@uref{#arm-x-aout,,arm-*-aout} +@item +@uref{#xscale-x-x,,xscale-*-*} +@item +@uref{#avr,,avr} +@item +@uref{#bfin,,Blackfin} +@item +@uref{#c4x,,c4x} +@item +@uref{#dos,,DOS} +@item +@uref{#x-x-freebsd,,*-*-freebsd*} +@item +@uref{#h8300-hms,,h8300-hms} +@item +@uref{#hppa-hp-hpux,,hppa*-hp-hpux*} +@item +@uref{#hppa-hp-hpux10,,hppa*-hp-hpux10} +@item +@uref{#hppa-hp-hpux11,,hppa*-hp-hpux11} +@item +@uref{#x-x-linux-gnu,,*-*-linux-gnu} +@item +@uref{#ix86-x-linuxaout,,i?86-*-linux*aout} +@item +@uref{#ix86-x-linux,,i?86-*-linux*} +@item +@uref{#ix86-x-sco32v5,,i?86-*-sco3.2v5*} +@item +@uref{#ix86-x-solaris210,,i?86-*-solaris2.10} +@item +@uref{#ix86-x-udk,,i?86-*-udk} +@item +@uref{#ia64-x-linux,,ia64-*-linux} +@item +@uref{#ia64-x-hpux,,ia64-*-hpux*} +@item +@uref{#x-ibm-aix,,*-ibm-aix*} +@item +@uref{#iq2000-x-elf,,iq2000-*-elf} +@item +@uref{#m32c-x-elf,,m32c-*-elf} +@item +@uref{#m32r-x-elf,,m32r-*-elf} +@item +@uref{#m6811-elf,,m6811-elf} +@item +@uref{#m6812-elf,,m6812-elf} +@item +@uref{#m68k-hp-hpux,,m68k-hp-hpux} +@item +@uref{#mips-x-x,,mips-*-*} +@item +@uref{#mips-sgi-irix5,,mips-sgi-irix5} +@item +@uref{#mips-sgi-irix6,,mips-sgi-irix6} +@item +@uref{#powerpc-x-x,,powerpc*-*-*, powerpc-*-sysv4} +@item +@uref{#powerpc-x-darwin,,powerpc-*-darwin*} +@item +@uref{#powerpc-x-elf,,powerpc-*-elf, powerpc-*-sysv4} +@item +@uref{#powerpc-x-linux-gnu,,powerpc*-*-linux-gnu*} +@item +@uref{#powerpc-x-netbsd,,powerpc-*-netbsd*} +@item +@uref{#powerpc-x-eabisim,,powerpc-*-eabisim} +@item +@uref{#powerpc-x-eabi,,powerpc-*-eabi} +@item +@uref{#powerpcle-x-elf,,powerpcle-*-elf, powerpcle-*-sysv4} +@item +@uref{#powerpcle-x-eabisim,,powerpcle-*-eabisim} +@item +@uref{#powerpcle-x-eabi,,powerpcle-*-eabi} +@item +@uref{#s390-x-linux,,s390-*-linux*} +@item +@uref{#s390x-x-linux,,s390x-*-linux*} +@item +@uref{#s390x-ibm-tpf,,s390x-ibm-tpf*} +@item +@uref{#x-x-solaris2,,*-*-solaris2*} +@item +@uref{#sparc-sun-solaris2,,sparc-sun-solaris2*} +@item +@uref{#sparc-sun-solaris27,,sparc-sun-solaris2.7} +@item +@uref{#sparc-x-linux,,sparc-*-linux*} +@item +@uref{#sparc64-x-solaris2,,sparc64-*-solaris2*} +@item +@uref{#sparcv9-x-solaris2,,sparcv9-*-solaris2*} +@item +@uref{#x-x-sysv,,*-*-sysv*} +@item +@uref{#vax-dec-ultrix,,vax-dec-ultrix} +@item +@uref{#x-x-vxworks,,*-*-vxworks*} +@item +@uref{#x86-64-x-x,,x86_64-*-*, amd64-*-*} +@item +@uref{#xtensa-x-elf,,xtensa-*-elf} +@item +@uref{#xtensa-x-linux,,xtensa-*-linux*} +@item +@uref{#windows,,Microsoft Windows} +@item +@uref{#os2,,OS/2} +@item +@uref{#older,,Older systems} +@end itemize + +@itemize +@item +@uref{#elf,,all ELF targets} (SVR4, Solaris 2, etc.) +@end itemize +@end ifhtml + + +@html +<!-- -------- host/target specific issues start here ---------------- --> +<hr /> +@end html +@heading @anchor{alpha-x-x}alpha*-*-* + +This section contains general configuration information for all +alpha-based platforms using ELF (in particular, ignore this section for +DEC OSF/1, Digital UNIX and Tru64 UNIX)@. In addition to reading this +section, please read all other sections that match your target. + +We require binutils 2.11.2 or newer. +Previous binutils releases had a number of problems with DWARF 2 +debugging information, not the least of which is incorrect linking of +shared libraries. + +@html +<hr /> +@end html +@heading @anchor{alpha-dec-osf}alpha*-dec-osf* +Systems using processors that implement the DEC Alpha architecture and +are running the DEC/Compaq Unix (DEC OSF/1, Digital UNIX, or Compaq +Tru64 UNIX) operating system, for example the DEC Alpha AXP systems. + +As of GCC 3.2, versions before @code{alpha*-dec-osf4} are no longer +supported. (These are the versions which identify themselves as DEC +OSF/1.) + +In Digital Unix V4.0, virtual memory exhausted bootstrap failures +may be fixed by configuring with @option{--with-gc=simple}, +reconfiguring Kernel Virtual Memory and Swap parameters +per the @command{/usr/sbin/sys_check} Tuning Suggestions, +or applying the patch in +@uref{http://gcc.gnu.org/ml/gcc/2002-08/msg00822.html}. + +In Tru64 UNIX V5.1, Compaq introduced a new assembler that does not +currently (2001-06-13) work with @command{mips-tfile}. As a workaround, +we need to use the old assembler, invoked via the barely documented +@option{-oldas} option. To bootstrap GCC, you either need to use the +Compaq C Compiler: + +@smallexample + % CC=cc @var{srcdir}/configure [@var{options}] [@var{target}] +@end smallexample + +or you can use a copy of GCC 2.95.3 or higher built on Tru64 UNIX V4.0: + +@smallexample + % CC=gcc -Wa,-oldas @var{srcdir}/configure [@var{options}] [@var{target}] +@end smallexample + +As of GNU binutils 2.11.2, neither GNU @command{as} nor GNU @command{ld} +are supported on Tru64 UNIX, so you must not configure GCC with +@option{--with-gnu-as} or @option{--with-gnu-ld}. + +GCC writes a @samp{.verstamp} directive to the assembler output file +unless it is built as a cross-compiler. It gets the version to use from +the system header file @file{/usr/include/stamp.h}. If you install a +new version of DEC Unix, you should rebuild GCC to pick up the new version +stamp. + +Note that since the Alpha is a 64-bit architecture, cross-compilers from +32-bit machines will not generate code as efficient as that generated +when the compiler is running on a 64-bit machine because many +optimizations that depend on being able to represent a word on the +target in an integral value on the host cannot be performed. Building +cross-compilers on the Alpha for 32-bit machines has only been tested in +a few cases and may not work properly. + +@samp{make compare} may fail on old versions of DEC Unix unless you add +@option{-save-temps} to @code{CFLAGS}. On these systems, the name of the +assembler input file is stored in the object file, and that makes +comparison fail if it differs between the @code{stage1} and +@code{stage2} compilations. The option @option{-save-temps} forces a +fixed name to be used for the assembler input file, instead of a +randomly chosen name in @file{/tmp}. Do not add @option{-save-temps} +unless the comparisons fail without that option. If you add +@option{-save-temps}, you will have to manually delete the @samp{.i} and +@samp{.s} files after each series of compilations. + +GCC now supports both the native (ECOFF) debugging format used by DBX +and GDB and an encapsulated STABS format for use only with GDB@. See the +discussion of the @option{--with-stabs} option of @file{configure} above +for more information on these formats and how to select them. + +There is a bug in DEC's assembler that produces incorrect line numbers +for ECOFF format when the @samp{.align} directive is used. To work +around this problem, GCC will not emit such alignment directives +while writing ECOFF format debugging information even if optimization is +being performed. Unfortunately, this has the very undesirable +side-effect that code addresses when @option{-O} is specified are +different depending on whether or not @option{-g} is also specified. + +To avoid this behavior, specify @option{-gstabs+} and use GDB instead of +DBX@. DEC is now aware of this problem with the assembler and hopes to +provide a fix shortly. + +@html +<hr /> +@end html +@heading @anchor{alphaev5-cray-unicosmk}alphaev5-cray-unicosmk* +Cray T3E systems running Unicos/Mk. + +This port is incomplete and has many known bugs. We hope to improve the +support for this target soon. Currently, only the C front end is supported, +and it is not possible to build parallel applications. Cray modules are not +supported; in particular, Craylibs are assumed to be in +@file{/opt/ctl/craylibs/craylibs}. + +On this platform, you need to tell GCC where to find the assembler and +the linker. The simplest way to do so is by providing @option{--with-as} +and @option{--with-ld} to @file{configure}, e.g.@: + +@smallexample + configure --with-as=/opt/ctl/bin/cam --with-ld=/opt/ctl/bin/cld \ + --enable-languages=c +@end smallexample + +The comparison test at the end of the bootstrapping process fails on Unicos/Mk +because the assembler inserts timestamps into object files. You should +be able to work around this by doing @samp{make all} after getting this +failure. + +@html +<hr /> +@end html +@heading @anchor{arc-x-elf}arc-*-elf +Argonaut ARC processor. +This configuration is intended for embedded systems. + +@html +<hr /> +@end html +@heading @anchor{arm-x-elf}arm-*-elf +@heading @anchor{xscale-x-x}xscale-*-* +ARM-family processors. Subtargets that use the ELF object format +require GNU binutils 2.13 or newer. Such subtargets include: +@code{arm-*-freebsd}, @code{arm-*-netbsdelf}, @code{arm-*-*linux}, +@code{arm-*-rtems} and @code{arm-*-kaos}. + +@html +<hr /> +@end html +@heading @anchor{arm-x-coff}arm-*-coff +ARM-family processors. Note that there are two different varieties +of PE format subtarget supported: @code{arm-wince-pe} and +@code{arm-pe} as well as a standard COFF target @code{arm-*-coff}. + +@html +<hr /> +@end html +@heading @anchor{arm-x-aout}arm-*-aout +ARM-family processors. These targets support the AOUT file format: +@code{arm-*-aout}, @code{arm-*-netbsd}. + +@html +<hr /> +@end html +@heading @anchor{avr}avr + +ATMEL AVR-family micro controllers. These are used in embedded +applications. There are no standard Unix configurations. +@ifnothtml +@xref{AVR Options,, AVR Options, gcc, Using the GNU Compiler +Collection (GCC)}, +@end ifnothtml +@ifhtml +See ``AVR Options'' in the main manual +@end ifhtml +for the list of supported MCU types. + +Use @samp{configure --target=avr --enable-languages="c"} to configure GCC@. + +Further installation notes and other useful information about AVR tools +can also be obtained from: + +@itemize @bullet +@item +@uref{http://www.nongnu.org/avr/,,http://www.nongnu.org/avr/} +@item +@uref{http://home.overta.ru/users/denisc/,,http://home.overta.ru/users/denisc/} +@item +@uref{http://www.amelek.gda.pl/avr/,,http://www.amelek.gda.pl/avr/} +@end itemize + +We @emph{strongly} recommend using binutils 2.13 or newer. + +The following error: +@smallexample + Error: register required +@end smallexample + +indicates that you should upgrade to a newer version of the binutils. + +@html +<hr /> +@end html +@heading @anchor{bfin}Blackfin + +The Blackfin processor, an Analog Devices DSP. +@ifnothtml +@xref{Blackfin Options,, Blackfin Options, gcc, Using the GNU Compiler +Collection (GCC)}, +@end ifnothtml +@ifhtml +See ``Blackfin Options'' in the main manual +@end ifhtml + +More information, and a version of binutils with support for this processor, +is available at @uref{http://blackfin.uclinux.org} + +@html +<hr /> +@end html +@heading @anchor{c4x}c4x + +Texas Instruments TMS320C3x and TMS320C4x Floating Point Digital Signal +Processors. These are used in embedded applications. There are no +standard Unix configurations. +@ifnothtml +@xref{TMS320C3x/C4x Options,, TMS320C3x/C4x Options, gcc, Using the +GNU Compiler Collection (GCC)}, +@end ifnothtml +@ifhtml +See ``TMS320C3x/C4x Options'' in the main manual +@end ifhtml +for the list of supported MCU types. + +GCC can be configured as a cross compiler for both the C3x and C4x +architectures on the same system. Use @samp{configure --target=c4x +--enable-languages="c,c++"} to configure. + + +Further installation notes and other useful information about C4x tools +can also be obtained from: + +@itemize @bullet +@item +@uref{http://www.elec.canterbury.ac.nz/c4x/,,http://www.elec.canterbury.ac.nz/c4x/} +@end itemize + +@html +<hr /> +@end html +@heading @anchor{cris}CRIS + +CRIS is the CPU architecture in Axis Communications ETRAX system-on-a-chip +series. These are used in embedded applications. + +@ifnothtml +@xref{CRIS Options,, CRIS Options, gcc, Using the GNU Compiler +Collection (GCC)}, +@end ifnothtml +@ifhtml +See ``CRIS Options'' in the main manual +@end ifhtml +for a list of CRIS-specific options. + +There are a few different CRIS targets: +@table @code +@item cris-axis-aout +Old target. Includes a multilib for the @samp{elinux} a.out-based +target. No multilibs for newer architecture variants. +@item cris-axis-elf +Mainly for monolithic embedded systems. Includes a multilib for the +@samp{v10} core used in @samp{ETRAX 100 LX}. +@item cris-axis-linux-gnu +A GNU/Linux port for the CRIS architecture, currently targeting +@samp{ETRAX 100 LX} by default. +@end table + +For @code{cris-axis-aout} and @code{cris-axis-elf} you need binutils 2.11 +or newer. For @code{cris-axis-linux-gnu} you need binutils 2.12 or newer. + +Pre-packaged tools can be obtained from +@uref{ftp://ftp.axis.com/pub/axis/tools/cris/compiler-kit/}. More +information about this platform is available at +@uref{http://developer.axis.com/}. + +@html +<hr /> +@end html +@heading @anchor{crx}CRX + +The CRX CompactRISC architecture is a low-power 32-bit architecture with +fast context switching and architectural extensibility features. + +@ifnothtml +@xref{CRX Options,, CRX Options, gcc, Using and Porting the GNU Compiler +Collection (GCC)}, +@end ifnothtml + +@ifhtml +See ``CRX Options'' in the main manual for a list of CRX-specific options. +@end ifhtml + +Use @samp{configure --target=crx-elf --enable-languages=c,c++} to configure +GCC@ for building a CRX cross-compiler. The option @samp{--target=crx-elf} +is also used to build the @samp{newlib} C library for CRX. + +It is also possible to build libstdc++-v3 for the CRX architecture. This +needs to be done in a separate step with the following configure settings: +@samp{gcc/libstdc++-v3/configure --host=crx-elf --with-newlib +--enable-sjlj-exceptions --enable-cxx-flags='-fexceptions -frtti'} + +@html +<hr /> +@end html +@heading @anchor{dos}DOS + +Please have a look at the @uref{binaries.html,,binaries page}. + +You cannot install GCC by itself on MSDOS; it will not compile under +any MSDOS compiler except itself. You need to get the complete +compilation package DJGPP, which includes binaries as well as sources, +and includes all the necessary compilation tools and libraries. + +@html +<hr /> +@end html +@heading @anchor{x-x-freebsd}*-*-freebsd* + +The version of binutils installed in @file{/usr/bin} probably works with +this release of GCC@. However, on FreeBSD 4, bootstrapping against the +latest FSF binutils is known to improve overall testsuite results; and, +on FreeBSD/alpha, using binutils 2.14 or later is required to build libjava. + +Support for FreeBSD 1 was discontinued in GCC 3.2. + +Support for FreeBSD 2 will be discontinued after GCC 3.4. The +following was true for GCC 3.1 but the current status is unknown. +For FreeBSD 2 or any mutant a.out versions of FreeBSD 3: All +configuration support and files as shipped with GCC 2.95 are still in +place. FreeBSD 2.2.7 has been known to bootstrap completely; however, +it is unknown which version of binutils was used (it is assumed that it +was the system copy in @file{/usr/bin}) and C++ EH failures were noted. + +For FreeBSD using the ELF file format: DWARF 2 debugging is now the +default for all CPU architectures. It had been the default on +FreeBSD/alpha since its inception. You may use @option{-gstabs} instead +of @option{-g}, if you really want the old debugging format. There are +no known issues with mixing object files and libraries with different +debugging formats. Otherwise, this release of GCC should now match more +of the configuration used in the stock FreeBSD configuration of GCC@. In +particular, @option{--enable-threads} is now configured by default. +However, as a general user, do not attempt to replace the system +compiler with this release. Known to bootstrap and check with good +results on FreeBSD 4.9-STABLE and 5-CURRENT@. In the past, known to +bootstrap and check with good results on FreeBSD 3.0, 3.4, 4.0, 4.2, +4.3, 4.4, 4.5, 4.8-STABLE@. + +In principle, @option{--enable-threads} is now compatible with +@option{--enable-libgcj} on FreeBSD@. However, it has only been built +and tested on @samp{i386-*-freebsd[45]} and @samp{alpha-*-freebsd[45]}. +The static +library may be incorrectly built (symbols are missing at link time). +There is a rare timing-based startup hang (probably involves an +assumption about the thread library). Multi-threaded boehm-gc (required for +libjava) exposes severe threaded signal-handling bugs on FreeBSD before +4.5-RELEASE@. Other CPU architectures +supported by FreeBSD will require additional configuration tuning in, at +the very least, both boehm-gc and libffi. + +Shared @file{libgcc_s.so} is now built and installed by default. + +@html +<hr /> +@end html +@heading @anchor{h8300-hms}h8300-hms +Renesas H8/300 series of processors. + +Please have a look at the @uref{binaries.html,,binaries page}. + +The calling convention and structure layout has changed in release 2.6. +All code must be recompiled. The calling convention now passes the +first three arguments in function calls in registers. Structures are no +longer a multiple of 2 bytes. + +@html +<hr /> +@end html +@heading @anchor{hppa-hp-hpux}hppa*-hp-hpux* +Support for HP-UX version 9 and older was discontinued in GCC 3.4. + +We require using gas/binutils on all hppa platforms; +you may encounter a variety of problems if you try to use the HP assembler. + +Specifically, @option{-g} does not work on HP-UX (since that system +uses a peculiar debugging format which GCC does not know about), unless +you use GAS and GDB@. It may be helpful to configure GCC with the +@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}} and +@option{--with-as=@dots{}} options to ensure that GCC can find GAS@. + +If you wish to use the pa-risc 2.0 architecture support with a 32-bit +runtime, you must use gas/binutils 2.11 or newer. + +There are two default scheduling models for instructions. These are +PROCESSOR_7100LC and PROCESSOR_8000. They are selected from the pa-risc +architecture specified for the target machine when configuring. +PROCESSOR_8000 is the default. PROCESSOR_7100LC is selected when +the target is a @samp{hppa1*} machine. + +The PROCESSOR_8000 model is not well suited to older processors. Thus, +it is important to completely specify the machine architecture when +configuring if you want a model other than PROCESSOR_8000. The macro +TARGET_SCHED_DEFAULT can be defined in BOOT_CFLAGS if a different +default scheduling model is desired. + +As of GCC 4.0, GCC uses the UNIX 95 namespace for HP-UX 10.10 +through 11.00, and the UNIX 98 namespace for HP-UX 11.11 and later. +This namespace change might cause problems when bootstrapping with +an earlier version of GCC or the HP compiler as essentially the same +namespace is required for an entire build. This problem can be avoided +in a number of ways. With HP cc, @env{UNIX_STD} can be set to @samp{95} +or @samp{98}. Another way is to add an appropriate set of predefines +to @env{CC}. The description for the @option{munix=} option contains +a list of the predefines used with each standard. + +As of GCC 4.1, @env{DWARF2} exception handling is available on HP-UX. +It is now the default. This exposed a bug in the handling of data +relocations in the GAS assembler. The handling of 64-bit data relocations +was seriously broken, affecting debugging and exception support on all +@samp{hppa64-*-*} targets. Under some circumstances, 32-bit data relocations +could also be handled incorrectly. This problem is fixed in GAS version +2.16.91 20051125. + +GCC versions prior to 4.1 incorrectly passed and returned complex +values. They are now passed in the same manner as aggregates. + +More specific information to @samp{hppa*-hp-hpux*} targets follows. + +@html +<hr /> +@end html +@heading @anchor{hppa-hp-hpux10}hppa*-hp-hpux10 + +For hpux10.20, we @emph{highly} recommend you pick up the latest sed patch +@code{PHCO_19798} from HP@. HP has two sites which provide patches free of +charge: + +@itemize @bullet +@item +@html +<a href="http://us.itrc.hp.com/service/home/home.do">US, Canada, Asia-Pacific, and +Latin-America</a> +@end html +@ifnothtml +@uref{http://us.itrc.hp.com/service/home/home.do,,} US, Canada, Asia-Pacific, +and Latin-America. +@end ifnothtml +@item +@uref{http://europe.itrc.hp.com/service/home/home.do,,} Europe. +@end itemize + +The HP assembler on these systems has some problems. Most notably the +assembler inserts timestamps into each object file it creates, causing +the 3-stage comparison test to fail during a bootstrap. +You should be able to continue by saying @samp{make all-host all-target} +after getting the failure from @samp{make}. + +GCC 4.0 requires CVS binutils as of April 28, 2004 or later. Earlier +versions require binutils 2.8 or later. + +The C++ ABI has changed incompatibly in GCC 4.0. COMDAT subspaces are +used for one-only code and data. This resolves many of the previous +problems in using C++ on this target. However, the ABI is not compatible +with the one implemented under HP-UX 11 using secondary definitions. + +@html +<hr /> +@end html +@heading @anchor{hppa-hp-hpux11}hppa*-hp-hpux11 + +GCC 3.0 and up support HP-UX 11. GCC 2.95.x is not supported and cannot +be used to compile GCC 3.0 and up. + +Refer to @uref{binaries.html,,binaries} for information about obtaining +precompiled GCC binaries for HP-UX@. Precompiled binaries must be obtained +to build the Ada language as it can't be bootstrapped using C@. Ada is +only available for the 32-bit PA-RISC runtime. The libffi and libjava +haven't been ported to HP-UX and don't build. + +Starting with GCC 3.4 an ISO C compiler is required to bootstrap. The +bundled compiler supports only traditional C; you will need either HP's +unbundled compiler, or a binary distribution of GCC@. + +It is possible to build GCC 3.3 starting with the bundled HP compiler, +but the process requires several steps. GCC 3.3 can then be used to +build later versions. The fastjar program contains ISO C code and +can't be built with the HP bundled compiler. This problem can be +avoided by not building the Java language. For example, use the +@option{--enable-languages="c,c++,f77,objc"} option in your configure +command. + +There are several possible approaches to building the distribution. +Binutils can be built first using the HP tools. Then, the GCC +distribution can be built. The second approach is to build GCC +first using the HP tools, then build binutils, then rebuild GCC@. +There have been problems with various binary distributions, so it +is best not to start from a binary distribution. + +On 64-bit capable systems, there are two distinct targets. Different +installation prefixes must be used if both are to be installed on +the same system. The @samp{hppa[1-2]*-hp-hpux11*} target generates code +for the 32-bit PA-RISC runtime architecture and uses the HP linker. +The @samp{hppa64-hp-hpux11*} target generates 64-bit code for the +PA-RISC 2.0 architecture. The HP and GNU linkers are both supported +for this target. + +The script config.guess now selects the target type based on the compiler +detected during configuration. You must define @env{PATH} or @env{CC} so +that configure finds an appropriate compiler for the initial bootstrap. +When @env{CC} is used, the definition should contain the options that are +needed whenever @env{CC} is used. + +Specifically, options that determine the runtime architecture must be +in @env{CC} to correctly select the target for the build. It is also +convenient to place many other compiler options in @env{CC}. For example, +@env{CC="cc -Ac +DA2.0W -Wp,-H16376 -D_CLASSIC_TYPES -D_HPUX_SOURCE"} +can be used to bootstrap the GCC 3.3 branch with the HP compiler in +64-bit K&R/bundled mode. The @option{+DA2.0W} option will result in +the automatic selection of the @samp{hppa64-hp-hpux11*} target. The +macro definition table of cpp needs to be increased for a successful +build with the HP compiler. _CLASSIC_TYPES and _HPUX_SOURCE need to +be defined when building with the bundled compiler, or when using the +@option{-Ac} option. These defines aren't necessary with @option{-Ae}. + +It is best to explicitly configure the @samp{hppa64-hp-hpux11*} target +with the @option{--with-ld=@dots{}} option. This overrides the standard +search for ld. The two linkers supported on this target require different +commands. The default linker is determined during configuration. As a +result, it's not possible to switch linkers in the middle of a GCC build. +This has been been reported to sometimes occur in unified builds of +binutils and GCC@. + +GCC 3.0 through 3.2 require binutils 2.11 or above. GCC 3.3 through +GCC 4.0 require binutils 2.14 or later. + +Although the HP assembler can be used for an initial build, it shouldn't +be used with any languages other than C and perhaps Fortran due to its +many limitations. For example, it does not support weak symbols or alias +definitions. As a result, explicit template instantiations are required +when using C++. This makes it difficult if not impossible to build many +C++ applications. You can't generate debugging information when using +the HP assembler. Finally, bootstrapping fails in the final +comparison of object modules due to the time stamps that it inserts into +the modules. The bootstrap can be continued from this point with +@samp{make all-host all-target}. + +A recent linker patch must be installed for the correct operation of +GCC 3.3 and later. @code{PHSS_26559} and @code{PHSS_24304} are the +oldest linker patches that are known to work. They are for HP-UX +11.00 and 11.11, respectively. @code{PHSS_24303}, the companion to +@code{PHSS_24304}, might be usable but it hasn't been tested. These +patches have been superseded. Consult the HP patch database to obtain +the currently recommended linker patch for your system. + +The patches are necessary for the support of weak symbols on the +32-bit port, and for the running of initializers and finalizers. Weak +symbols are implemented using SOM secondary definition symbols. Prior +to HP-UX 11, there are bugs in the linker support for secondary symbols. +The patches correct a problem of linker core dumps creating shared +libraries containing secondary symbols, as well as various other +linking issues involving secondary symbols. + +GCC 3.3 uses the ELF DT_INIT_ARRAY and DT_FINI_ARRAY capabilities to +run initializers and finalizers on the 64-bit port. The 32-bit port +uses the linker @option{+init} and @option{+fini} options for the same +purpose. The patches correct various problems with the +init/+fini +options, including program core dumps. Binutils 2.14 corrects a +problem on the 64-bit port resulting from HP's non-standard use of +the .init and .fini sections for array initializers and finalizers. + +There are a number of issues to consider in selecting which linker to +use with the 64-bit port. The GNU 64-bit linker can only create dynamic +binaries. The @option{-static} option causes linking with archive +libraries but doesn't produce a truly static binary. Dynamic binaries +still require final binding by the dynamic loader to resolve a set of +dynamic-loader-defined symbols. The default behavior of the HP linker +is the same as the GNU linker. However, it can generate true 64-bit +static binaries using the @option{+compat} option. + +The HP 64-bit linker doesn't support linkonce semantics. As a +result, C++ programs have many more sections than they should. + +The GNU 64-bit linker has some issues with shared library support +and exceptions. As a result, we only support libgcc in archive +format. For similar reasons, dwarf2 unwind and exception support +are disabled. The GNU linker also has problems creating binaries +with @option{-static}. It doesn't provide stubs for internal +calls to global functions in shared libraries, so these calls +can't be overloaded. + +Thread support is not implemented in GCC 3.0 through 3.2, so the +@option{--enable-threads} configure option does not work. In 3.3 +and later, POSIX threads are supported. The optional DCE thread +library is not supported. + +This port still is undergoing significant development. + +@html +<hr /> +@end html +@heading @anchor{x-x-linux-gnu}*-*-linux-gnu + +Versions of libstdc++-v3 starting with 3.2.1 require bugfixes present +in glibc 2.2.5 and later. More information is available in the +libstdc++-v3 documentation. + +@html +<hr /> +@end html +@heading @anchor{ix86-x-linuxaout}i?86-*-linux*aout +Use this configuration to generate @file{a.out} binaries on Linux-based +GNU systems. This configuration is being superseded. + +@html +<hr /> +@end html +@heading @anchor{ix86-x-linux}i?86-*-linux* + +As of GCC 3.3, binutils 2.13.1 or later is required for this platform. +See @uref{http://gcc.gnu.org/PR10877,,bug 10877} for more information. + +If you receive Signal 11 errors when building on GNU/Linux, then it is +possible you have a hardware problem. Further information on this can be +found on @uref{http://www.bitwizard.nl/sig11/,,www.bitwizard.nl}. + +@html +<hr /> +@end html +@heading @anchor{ix86-x-sco32v5}i?86-*-sco3.2v5* +Use this for the SCO OpenServer Release 5 family of operating systems. + +Unlike earlier versions of GCC, the ability to generate COFF with this +target is no longer provided. + +Earlier versions of GCC emitted DWARF 1 when generating ELF to allow +the system debugger to be used. That support was too burdensome to +maintain. GCC now emits only DWARF 2 for this target. This means you +may use either the UDK debugger or GDB to debug programs built by this +version of GCC@. + +GCC is now only supported on releases 5.0.4 and later, and requires that +you install Support Level Supplement OSS646B or later, and Support Level +Supplement OSS631C or later. If you are using release 5.0.7 of +OpenServer, you must have at least the first maintenance pack installed +(this includes the relevant portions of OSS646). OSS646, also known as +the ``Execution Environment Update'', provides updated link editors and +assemblers, as well as updated standard C and math libraries. The C +startup modules are also updated to support the System V gABI draft, and +GCC relies on that behavior. OSS631 provides a collection of commonly +used open source libraries, some of which GCC depends on (such as GNU +gettext and zlib). SCO OpenServer Release 5.0.7 has all of this built +in by default, but OSS631C and later also apply to that release. Please +visit +@uref{ftp://ftp.sco.com/pub/openserver5,,ftp://ftp.sco.com/pub/openserver5} +for the latest versions of these (and other potentially useful) +supplements. + +Although there is support for using the native assembler, it is +recommended that you configure GCC to use the GNU assembler. You do +this by using the flags +@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}}. You should +use a modern version of GNU binutils. Version 2.13.2.1 was used for all +testing. In general, only the @option{--with-gnu-as} option is tested. +A modern bintuils (as well as a plethora of other development related +GNU utilities) can be found in Support Level Supplement OSS658A, the +``GNU Development Tools'' package. See the SCO web and ftp sites for details. +That package also contains the currently ``officially supported'' version of +GCC, version 2.95.3. It is useful for bootstrapping this version. + +@html +<hr /> +@end html +@heading @anchor{ix86-x-solaris210}i?86-*-solaris2.10 +Use this for Solaris 10 or later on x86 and x86-64 systems. This +configuration is supported by GCC 4.0 and later versions only. + +It is recommended that you configure GCC to use the GNU assembler in +@file{/usr/sfw/bin/gas} but the Sun linker, using the options +@option{--with-gnu-as --with-as=/usr/sfw/bin/gas --without-gnu-ld +--with-ld=/usr/ccs/bin/ld}. + +@html +<hr /> +@end html +@heading @anchor{ix86-x-udk}i?86-*-udk + +This target emulates the SCO Universal Development Kit and requires that +package be installed. (If it is installed, you will have a +@file{/udk/usr/ccs/bin/cc} file present.) It's very much like the +@samp{i?86-*-unixware7*} target +but is meant to be used when hosting on a system where UDK isn't the +default compiler such as OpenServer 5 or Unixware 2. This target will +generate binaries that will run on OpenServer, Unixware 2, or Unixware 7, +with the same warnings and caveats as the SCO UDK@. + +This target is a little tricky to build because we have to distinguish +it from the native tools (so it gets headers, startups, and libraries +from the right place) while making the tools not think we're actually +building a cross compiler. The easiest way to do this is with a configure +command like this: + +@smallexample + CC=/udk/usr/ccs/bin/cc @var{/your/path/to}/gcc/configure \ + --host=i686-pc-udk --target=i686-pc-udk --program-prefix=udk- +@end smallexample + +@emph{You should substitute @samp{i686} in the above command with the appropriate +processor for your host.} + +After the usual @samp{make} and +@samp{make install}, you can then access the UDK-targeted GCC +tools by adding @command{udk-} before the commonly known name. For +example, to invoke the C compiler, you would use @command{udk-gcc}. +They will coexist peacefully with any native-target GCC tools you may +have installed. + + +@html +<hr /> +@end html +@heading @anchor{ia64-x-linux}ia64-*-linux +IA-64 processor (also known as IPF, or Itanium Processor Family) +running GNU/Linux. + +If you are using the installed system libunwind library with +@option{--with-system-libunwind}, then you must use libunwind 0.98 or +later. + +None of the following versions of GCC has an ABI that is compatible +with any of the other versions in this list, with the exception that +Red Hat 2.96 and Trillian 000171 are compatible with each other: +3.1, 3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717. +This primarily affects C++ programs and programs that create shared libraries. +GCC 3.1 or later is recommended for compiling linux, the kernel. +As of version 3.1 GCC is believed to be fully ABI compliant, and hence no +more major ABI changes are expected. + +@html +<hr /> +@end html +@heading @anchor{ia64-x-hpux}ia64-*-hpux* +Building GCC on this target requires the GNU Assembler. The bundled HP +assembler will not work. To prevent GCC from using the wrong assembler, +the option @option{--with-gnu-as} may be necessary. + +The GCC libunwind library has not been ported to HPUX@. This means that for +GCC versions 3.2.3 and earlier, @option{--enable-libunwind-exceptions} +is required to build GCC@. For GCC 3.3 and later, this is the default. +For gcc 3.4.3 and later, @option{--enable-libunwind-exceptions} is +removed and the system libunwind library will always be used. + +@html +<hr /> +<!-- rs6000-ibm-aix*, powerpc-ibm-aix* --> +@end html +@heading @anchor{x-ibm-aix}*-ibm-aix* +Support for AIX version 3 and older was discontinued in GCC 3.4. + +``out of memory'' bootstrap failures may indicate a problem with +process resource limits (ulimit). Hard limits are configured in the +@file{/etc/security/limits} system configuration file. + +To speed up the configuration phases of bootstrapping and installing GCC, +one may use GNU Bash instead of AIX @command{/bin/sh}, e.g., + +@smallexample + % CONFIG_SHELL=/opt/freeware/bin/bash + % export CONFIG_SHELL +@end smallexample + +and then proceed as described in @uref{build.html,,the build +instructions}, where we strongly recommend specifying an absolute path +to invoke @var{srcdir}/configure. + +Because GCC on AIX is built as a 32-bit executable by default, +(although it can generate 64-bit programs) the GMP and MPFR libraries +required by gfortran must be 32-bit libraries. Building GMP and MPFR +as static archive libraries works better than shared libraries. + +Errors involving @code{alloca} when building GCC generally are due +to an incorrect definition of @code{CC} in the Makefile or mixing files +compiled with the native C compiler and GCC@. During the stage1 phase of +the build, the native AIX compiler @strong{must} be invoked as @command{cc} +(not @command{xlc}). Once @command{configure} has been informed of +@command{xlc}, one needs to use @samp{make distclean} to remove the +configure cache files and ensure that @env{CC} environment variable +does not provide a definition that will confuse @command{configure}. +If this error occurs during stage2 or later, then the problem most likely +is the version of Make (see above). + +The native @command{as} and @command{ld} are recommended for bootstrapping +on AIX 4 and required for bootstrapping on AIX 5L@. The GNU Assembler +reports that it supports WEAK symbols on AIX 4, which causes GCC to try to +utilize weak symbol functionality although it is not supported. The GNU +Assembler and Linker do not support AIX 5L sufficiently to bootstrap GCC@. +The native AIX tools do interoperate with GCC@. + +Building @file{libstdc++.a} requires a fix for an AIX Assembler bug +APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1). It also requires a +fix for another AIX Assembler bug and a co-dependent AIX Archiver fix +referenced as APAR IY53606 (AIX 5.2) or a APAR IY54774 (AIX 5.1) + +@samp{libstdc++} in GCC 3.4 increments the major version number of the +shared object and GCC installation places the @file{libstdc++.a} +shared library in a common location which will overwrite the and GCC +3.3 version of the shared library. Applications either need to be +re-linked against the new shared library or the GCC 3.1 and GCC 3.3 +versions of the @samp{libstdc++} shared object needs to be available +to the AIX runtime loader. The GCC 3.1 @samp{libstdc++.so.4}, if +present, and GCC 3.3 @samp{libstdc++.so.5} shared objects can be +installed for runtime dynamic loading using the following steps to set +the @samp{F_LOADONLY} flag in the shared object for @emph{each} +multilib @file{libstdc++.a} installed: + +Extract the shared objects from the currently installed +@file{libstdc++.a} archive: +@smallexample + % ar -x libstdc++.a libstdc++.so.4 libstdc++.so.5 +@end smallexample + +Enable the @samp{F_LOADONLY} flag so that the shared object will be +available for runtime dynamic loading, but not linking: +@smallexample + % strip -e libstdc++.so.4 libstdc++.so.5 +@end smallexample + +Archive the runtime-only shared object in the GCC 3.4 +@file{libstdc++.a} archive: +@smallexample + % ar -q libstdc++.a libstdc++.so.4 libstdc++.so.5 +@end smallexample + +Linking executables and shared libraries may produce warnings of +duplicate symbols. The assembly files generated by GCC for AIX always +have included multiple symbol definitions for certain global variable +and function declarations in the original program. The warnings should +not prevent the linker from producing a correct library or runnable +executable. + +AIX 4.3 utilizes a ``large format'' archive to support both 32-bit and +64-bit object modules. The routines provided in AIX 4.3.0 and AIX 4.3.1 +to parse archive libraries did not handle the new format correctly. +These routines are used by GCC and result in error messages during +linking such as ``not a COFF file''. The version of the routines shipped +with AIX 4.3.1 should work for a 32-bit environment. The @option{-g} +option of the archive command may be used to create archives of 32-bit +objects using the original ``small format''. A correct version of the +routines is shipped with AIX 4.3.2 and above. + +Some versions of the AIX binder (linker) can fail with a relocation +overflow severe error when the @option{-bbigtoc} option is used to link +GCC-produced object files into an executable that overflows the TOC@. A fix +for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is +available from IBM Customer Support and from its +@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com} +website as PTF U455193. + +The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core +with a segmentation fault when invoked by any version of GCC@. A fix for +APAR IX87327 is available from IBM Customer Support and from its +@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com} +website as PTF U461879. This fix is incorporated in AIX 4.3.3 and above. + +The initial assembler shipped with AIX 4.3.0 generates incorrect object +files. A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS +TO ASSEMBLE/BIND) is available from IBM Customer Support and from its +@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com} +website as PTF U453956. This fix is incorporated in AIX 4.3.1 and above. + +AIX provides National Language Support (NLS)@. Compilers and assemblers +use NLS to support locale-specific representations of various data +formats including floating-point numbers (e.g., @samp{.} vs @samp{,} for +separating decimal fractions). There have been problems reported where +GCC does not produce the same floating-point formats that the assembler +expects. If one encounters this problem, set the @env{LANG} +environment variable to @samp{C} or @samp{En_US}. + +By default, GCC for AIX 4.1 and above produces code that can be used on +both Power or PowerPC processors. + +A default can be specified with the @option{-mcpu=@var{cpu_type}} +switch and using the configure option @option{--with-cpu-@var{cpu_type}}. + +@html +<hr /> +@end html +@heading @anchor{iq2000-x-elf}iq2000-*-elf +Vitesse IQ2000 processors. These are used in embedded +applications. There are no standard Unix configurations. + +@html +<hr /> +@end html +@heading @anchor{m32c-x-elf}m32c-*-elf +Renesas M32C processor. +This configuration is intended for embedded systems. + +@html +<hr /> +@end html +@heading @anchor{m32r-x-elf}m32r-*-elf +Renesas M32R processor. +This configuration is intended for embedded systems. + +@html +<hr /> +@end html +@heading @anchor{m6811-elf}m6811-elf +Motorola 68HC11 family micro controllers. These are used in embedded +applications. There are no standard Unix configurations. + +@html +<hr /> +@end html +@heading @anchor{m6812-elf}m6812-elf +Motorola 68HC12 family micro controllers. These are used in embedded +applications. There are no standard Unix configurations. + +@html +<hr /> +@end html +@heading @anchor{m68k-hp-hpux}m68k-hp-hpux +HP 9000 series 300 or 400 running HP-UX@. HP-UX version 8.0 has a bug in +the assembler that prevents compilation of GCC@. This +bug manifests itself during the first stage of compilation, while +building @file{libgcc2.a}: + +@smallexample +_floatdisf +cc1: warning: `-g' option not supported on this version of GCC +cc1: warning: `-g1' option not supported on this version of GCC +./xgcc: Internal compiler error: program as got fatal signal 11 +@end smallexample + +A patched version of the assembler is available as the file +@uref{ftp://altdorf.ai.mit.edu/archive/cph/hpux-8.0-assembler}. If you +have HP software support, the patch can also be obtained directly from +HP, as described in the following note: + +@quotation +This is the patched assembler, to patch SR#1653-010439, where the +assembler aborts on floating point constants. + +The bug is not really in the assembler, but in the shared library +version of the function ``cvtnum(3c)''. The bug on ``cvtnum(3c)'' is +SR#4701-078451. Anyway, the attached assembler uses the archive +library version of ``cvtnum(3c)'' and thus does not exhibit the bug. +@end quotation + +This patch is also known as PHCO_4484. + +In addition gdb does not understand that native HP-UX format, so +you must use gas if you wish to use gdb. + +On HP-UX version 8.05, but not on 8.07 or more recent versions, the +@command{fixproto} shell script triggers a bug in the system shell. If you +encounter this problem, upgrade your operating system or use BASH (the +GNU shell) to run @command{fixproto}. This bug will cause the fixproto +program to report an error of the form: + +@smallexample +./fixproto: sh internal 1K buffer overflow +@end smallexample + +To fix this, you can also change the first line of the fixproto script +to look like: + +@smallexample +#!/bin/ksh +@end smallexample + +@html +<hr /> +@end html +@heading @anchor{mips-x-x}mips-*-* +If on a MIPS system you get an error message saying ``does not have gp +sections for all it's [sic] sectons [sic]'', don't worry about it. This +happens whenever you use GAS with the MIPS linker, but there is not +really anything wrong, and it is okay to use the output file. You can +stop such warnings by installing the GNU linker. + +It would be nice to extend GAS to produce the gp tables, but they are +optional, and there should not be a warning about their absence. + +The libstdc++ atomic locking routines for MIPS targets requires MIPS II +and later. A patch went in just after the GCC 3.3 release to +make @samp{mips*-*-*} use the generic implementation instead. You can also +configure for @samp{mipsel-elf} as a workaround. The +@samp{mips*-*-linux*} target continues to use the MIPS II routines. More +work on this is expected in future releases. + +MIPS systems check for division by zero (unless +@option{-mno-check-zero-division} is passed to the compiler) by +generating either a conditional trap or a break instruction. Using +trap results in smaller code, but is only supported on MIPS II and +later. Also, some versions of the Linux kernel have a bug that +prevents trap from generating the proper signal (@code{SIGFPE}). To enable +the use of break, use the @option{--with-divide=breaks} +@command{configure} option when configuring GCC@. The default is to +use traps on systems that support them. + +Cross-compilers for the MIPS as target using the MIPS assembler +currently do not work, because the auxiliary programs +@file{mips-tdump.c} and @file{mips-tfile.c} can't be compiled on +anything but a MIPS. It does work to cross compile for a MIPS +if you use the GNU assembler and linker. + +The assembler from GNU binutils 2.17 and earlier has a bug in the way +it sorts relocations for REL targets (o32, o64, EABI). This can cause +bad code to be generated for simple C++ programs. Also the linker +from GNU binutils versions prior to 2.17 has a bug which causes the +runtime linker stubs in very large programs, like @file{libgcj.so}, to +be incorrectly generated. Binutils CVS snapshots and releases made +after Nov. 9, 2006 are thought to be free from both of these problems. + +@html +<hr /> +@end html +@heading @anchor{mips-sgi-irix5}mips-sgi-irix5 + +In order to compile GCC on an SGI running IRIX 5, the @samp{compiler_dev.hdr} +subsystem must be installed from the IDO CD-ROM supplied by SGI@. +It is also available for download from +@uref{ftp://ftp.sgi.com/sgi/IRIX5.3/iris-development-option-5.3.tardist}. + +If you use the MIPS C compiler to bootstrap, it may be necessary +to increase its table size for switch statements with the +@option{-Wf,-XNg1500} option. If you use the @option{-O2} +optimization option, you also need to use @option{-Olimit 3000}. + +To enable debugging under IRIX 5, you must use GNU binutils 2.15 or +later, and use the @option{--with-gnu-ld} @command{configure} option +when configuring GCC@. You need to use GNU @command{ar} and @command{nm}, +also distributed with GNU binutils. + +Some users have reported that @command{/bin/sh} will hang during bootstrap. +This problem can be avoided by running the commands: + +@smallexample + % CONFIG_SHELL=/bin/ksh + % export CONFIG_SHELL +@end smallexample + +before starting the build. + +@html +<hr /> +@end html +@heading @anchor{mips-sgi-irix6}mips-sgi-irix6 + +If you are using SGI's MIPSpro @command{cc} as your bootstrap compiler, you must +ensure that the N32 ABI is in use. To test this, compile a simple C +file with @command{cc} and then run @command{file} on the +resulting object file. The output should look like: + +@smallexample +test.o: ELF N32 MSB @dots{} +@end smallexample + +If you see: + +@smallexample +test.o: ELF 32-bit MSB @dots{} +@end smallexample + +or + +@smallexample +test.o: ELF 64-bit MSB @dots{} +@end smallexample + +then your version of @command{cc} uses the O32 or N64 ABI by default. You +should set the environment variable @env{CC} to @samp{cc -n32} +before configuring GCC@. + +If you want the resulting @command{gcc} to run on old 32-bit systems +with the MIPS R4400 CPU, you need to ensure that only code for the @samp{mips3} +instruction set architecture (ISA) is generated. While GCC 3.x does +this correctly, both GCC 2.95 and SGI's MIPSpro @command{cc} may change +the ISA depending on the machine where GCC is built. Using one of them +as the bootstrap compiler may result in @samp{mips4} code, which won't run at +all on @samp{mips3}-only systems. For the test program above, you should see: + +@smallexample +test.o: ELF N32 MSB mips-3 @dots{} +@end smallexample + +If you get: + +@smallexample +test.o: ELF N32 MSB mips-4 @dots{} +@end smallexample + +instead, you should set the environment variable @env{CC} to @samp{cc +-n32 -mips3} or @samp{gcc -mips3} respectively before configuring GCC@. + +MIPSpro C 7.4 may cause bootstrap failures, due to a bug when inlining +@code{memcmp}. Either add @code{-U__INLINE_INTRINSICS} to the @env{CC} +environment variable as a workaround or upgrade to MIPSpro C 7.4.1m. + +GCC on IRIX 6 is usually built to support the N32, O32 and N64 ABIs. If +you build GCC on a system that doesn't have the N64 libraries installed +or cannot run 64-bit binaries, +you need to configure with @option{--disable-multilib} so GCC doesn't +try to use them. This will disable building the O32 libraries, too. +Look for @file{/usr/lib64/libc.so.1} to see if you +have the 64-bit libraries installed. + +To enable debugging for the O32 ABI, you must use GNU @command{as} from +GNU binutils 2.15 or later. You may also use GNU @command{ld}, but +this is not required and currently causes some problems with Ada. + +The @option{--enable-threads} option doesn't currently work, a patch is +in preparation for a future release. The @option{--enable-libgcj} +option is disabled by default: IRIX 6 uses a very low default limit +(20480) for the command line length. Although @command{libtool} contains a +workaround for this problem, at least the N64 @samp{libgcj} is known not +to build despite this, running into an internal error of the native +@command{ld}. A sure fix is to increase this limit (@samp{ncargs}) to +its maximum of 262144 bytes. If you have root access, you can use the +@command{systune} command to do this. + +@code{wchar_t} support in @samp{libstdc++} is not available for old +IRIX 6.5.x releases, @math{x < 19}. The problem cannot be autodetected +and in order to build GCC for such targets you need to configure with +@option{--disable-wchar_t}. + +See @uref{http://freeware.sgi.com/} for more +information about using GCC on IRIX platforms. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-x}powerpc-*-* + +You can specify a default version for the @option{-mcpu=@var{cpu_type}} +switch by using the configure option @option{--with-cpu-@var{cpu_type}}. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-darwin}powerpc-*-darwin* +PowerPC running Darwin (Mac OS X kernel). + +Pre-installed versions of Mac OS X may not include any developer tools, +meaning that you will not be able to build GCC from source. Tool +binaries are available at +@uref{http://developer.apple.com/darwin/projects/compiler/} (free +registration required). + +This version of GCC requires at least cctools-590.7. + +The version of GCC shipped by Apple typically includes a number of +extensions not available in a standard GCC release. These extensions +are generally for backwards compatibility and best avoided. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-elf}powerpc-*-elf, powerpc-*-sysv4 +PowerPC system in big endian mode, running System V.4. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-linux-gnu}powerpc*-*-linux-gnu* + +You will need +@uref{ftp://ftp.kernel.org/pub/linux/devel/binutils,,binutils 2.15} +or newer for a working GCC@. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-netbsd}powerpc-*-netbsd* +PowerPC system in big endian mode running NetBSD@. To build the +documentation you will need Texinfo version 4.4 (NetBSD 1.5.1 included +Texinfo version 3.12). + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-eabisim}powerpc-*-eabisim +Embedded PowerPC system in big endian mode for use in running under the +PSIM simulator. + +@html +<hr /> +@end html +@heading @anchor{powerpc-x-eabi}powerpc-*-eabi +Embedded PowerPC system in big endian mode. + +@html +<hr /> +@end html +@heading @anchor{powerpcle-x-elf}powerpcle-*-elf, powerpcle-*-sysv4 +PowerPC system in little endian mode, running System V.4. + +@html +<hr /> +@end html +@heading @anchor{powerpcle-x-eabisim}powerpcle-*-eabisim +Embedded PowerPC system in little endian mode for use in running under +the PSIM simulator. + +@html +<hr /> +@end html +@heading @anchor{powerpcle-x-eabi}powerpcle-*-eabi +Embedded PowerPC system in little endian mode. + +@html +<hr /> +@end html +@heading @anchor{s390-x-linux}s390-*-linux* +S/390 system running GNU/Linux for S/390@. + +@html +<hr /> +@end html +@heading @anchor{s390x-x-linux}s390x-*-linux* +zSeries system (64-bit) running GNU/Linux for zSeries@. + +@html +<hr /> +@end html +@heading @anchor{s390x-ibm-tpf}s390x-ibm-tpf* +zSeries system (64-bit) running TPF@. This platform is +supported as cross-compilation target only. + +@html +<hr /> +@end html +@c Please use Solaris 2 to refer to all release of Solaris, starting +@c with 2.0 until 2.6, 7, 8, etc. Solaris 1 was a marketing name for +@c SunOS 4 releases which we don't use to avoid confusion. Solaris +@c alone is too unspecific and must be avoided. +@heading @anchor{x-x-solaris2}*-*-solaris2* + +Sun does not ship a C compiler with Solaris 2. To bootstrap and install +GCC you first have to install a pre-built compiler, see the +@uref{binaries.html,,binaries page} for details. + +The Solaris 2 @command{/bin/sh} will often fail to configure +@file{libstdc++-v3}, @file{boehm-gc} or @file{libjava}. We therefore +recommend using the following initial sequence of commands + +@smallexample + % CONFIG_SHELL=/bin/ksh + % export CONFIG_SHELL +@end smallexample + +and proceed as described in @uref{configure.html,,the configure instructions}. +In addition we strongly recommend specifying an absolute path to invoke +@var{srcdir}/configure. + +Solaris 2 comes with a number of optional OS packages. Some of these +are needed to use GCC fully, namely @code{SUNWarc}, +@code{SUNWbtool}, @code{SUNWesu}, @code{SUNWhea}, @code{SUNWlibm}, +@code{SUNWsprot}, and @code{SUNWtoo}. If you did not install all +optional packages when installing Solaris 2, you will need to verify that +the packages that GCC needs are installed. + +To check whether an optional package is installed, use +the @command{pkginfo} command. To add an optional package, use the +@command{pkgadd} command. For further details, see the Solaris 2 +documentation. + +Trying to use the linker and other tools in +@file{/usr/ucb} to install GCC has been observed to cause trouble. +For example, the linker may hang indefinitely. The fix is to remove +@file{/usr/ucb} from your @env{PATH}. + +The build process works more smoothly with the legacy Sun tools so, if you +have @file{/usr/xpg4/bin} in your @env{PATH}, we recommend that you place +@file{/usr/bin} before @file{/usr/xpg4/bin} for the duration of the build. + +All releases of GNU binutils prior to 2.11.2 have known bugs on this +platform. We recommend the use of GNU binutils 2.11.2 or later, or the +vendor tools (Sun @command{as}, Sun @command{ld}). Note that your mileage +may vary if you use a combination of the GNU tools and the Sun tools: while +the combination GNU @command{as} + Sun @command{ld} should reasonably work, +the reverse combination Sun @command{as} + GNU @command{ld} is known to +cause memory corruption at runtime in some cases for C++ programs. + +The stock GNU binutils 2.15 release is broken on this platform because of a +single bug. It has been fixed on the 2.15 branch in the CVS repository. +You can obtain a working version by checking out the binutils-2_15-branch +from the CVS repository or applying the patch +@uref{http://sourceware.org/ml/binutils-cvs/2004-09/msg00036.html} to the +release. + +We recommend using GNU binutils 2.16 or later in conjunction with GCC 4.x, +or the vendor tools (Sun @command{as}, Sun @command{ld}). However, for +Solaris 10 and above, an additional patch is required in order for the GNU +linker to be able to cope with a new flavor of shared libraries. You +can obtain a working version by checking out the binutils-2_16-branch from +the CVS repository or applying the patch +@uref{http://sourceware.org/ml/binutils-cvs/2005-07/msg00122.html} to the +release. + +Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or +newer: @command{g++} will complain that types are missing. These headers assume +that omitting the type means @code{int}; this assumption worked for C89 but +is wrong for C++, and is now wrong for C99 also. + +@command{g++} accepts such (invalid) constructs with the option +@option{-fpermissive}; it +will assume that any missing type is @code{int} (as defined by C89). + +There are patches for Solaris 2.6 (105633-56 or newer for SPARC, +106248-42 or newer for Intel), Solaris 7 (108376-21 or newer for SPARC, +108377-20 for Intel), and Solaris 8 (108652-24 or newer for SPARC, +108653-22 for Intel) that fix this bug. + +Sun bug 4927647 sometimes causes random spurious testsuite failures +related to missing diagnostic output. This bug doesn't affect GCC +itself, rather it is a kernel bug triggered by the @command{expect} +program which is used only by the GCC testsuite driver. When the bug +causes the @command{expect} program to miss anticipated output, extra +testsuite failures appear. + +There are patches for Solaris 8 (117350-12 or newer for SPARC, +117351-12 or newer for Intel) and Solaris 9 (117171-11 or newer for +SPARC, 117172-11 or newer for Intel) that address this problem. + +@html +<hr /> +@end html +@heading @anchor{sparc-sun-solaris2}sparc-sun-solaris2* + +When GCC is configured to use binutils 2.11.2 or later the binaries +produced are smaller than the ones produced using Sun's native tools; +this difference is quite significant for binaries containing debugging +information. + +Sun @command{as} 4.x is broken in that it cannot cope with long symbol names. +A typical error message might look similar to the following: + +@smallexample +/usr/ccs/bin/as: "/var/tmp/ccMsw135.s", line 11041: error: + can't compute value of an expression involving an external symbol. +@end smallexample + +This is Sun bug 4237974. This is fixed with patch 108908-02 for Solaris +2.6 and has been fixed in later (5.x) versions of the assembler, +starting with Solaris 7. + +Starting with Solaris 7, the operating system is capable of executing +64-bit SPARC V9 binaries. GCC 3.1 and later properly supports +this; the @option{-m64} option enables 64-bit code generation. +However, if all you want is code tuned for the UltraSPARC CPU, you +should try the @option{-mtune=ultrasparc} option instead, which produces +code that, unlike full 64-bit code, can still run on non-UltraSPARC +machines. + +When configuring on a Solaris 7 or later system that is running a kernel +that supports only 32-bit binaries, one must configure with +@option{--disable-multilib}, since we will not be able to build the +64-bit target libraries. + +GCC 3.3 and GCC 3.4 trigger code generation bugs in earlier versions of +the GNU compiler (especially GCC 3.0.x versions), which lead to the +miscompilation of the stage1 compiler and the subsequent failure of the +bootstrap process. A workaround is to use GCC 3.2.3 as an intermediary +stage, i.e.@: to bootstrap that compiler with the base compiler and then +use it to bootstrap the final compiler. + +GCC 3.4 triggers a code generation bug in versions 5.4 (Sun ONE Studio 7) +and 5.5 (Sun ONE Studio 8) of the Sun compiler, which causes a bootstrap +failure in form of a miscompilation of the stage1 compiler by the Sun +compiler. This is Sun bug 4974440. This is fixed with patch 112760-07. + +GCC 3.4 changed the default debugging format from STABS to DWARF-2 for +32-bit code on Solaris 7 and later. If you use the Sun assembler, this +change apparently runs afoul of Sun bug 4910101 (which is referenced as +a x86-only problem by Sun, probably because they do not use DWARF-2). +A symptom of the problem is that you cannot compile C++ programs like +@command{groff} 1.19.1 without getting messages similar to the following: + +@smallexample +ld: warning: relocation error: R_SPARC_UA32: @dots{} + external symbolic relocation against non-allocatable section + .debug_info cannot be processed at runtime: relocation ignored. +@end smallexample + +To work around this problem, compile with @option{-gstabs+} instead of +plain @option{-g}. + +When configuring the GNU Multiple Precision Library (GMP) or the MPFR +library on a Solaris 7 or later system, the canonical target triplet +must be specified as the @command{build} parameter on the configure +line. This triplet can be obtained by invoking ./config.guess in +the toplevel source directory of GCC (and not that of GMP or MPFR). +For example on a Solaris 7 system: + +@smallexample + % ./configure --build=sparc-sun-solaris2.7 --prefix=xxx +@end smallexample + +@html +<hr /> +@end html +@heading @anchor{sparc-sun-solaris27}sparc-sun-solaris2.7 + +Sun patch 107058-01 (1999-01-13) for Solaris 7/SPARC triggers a bug in +the dynamic linker. This problem (Sun bug 4210064) affects GCC 2.8 +and later, including all EGCS releases. Sun formerly recommended +107058-01 for all Solaris 7 users, but around 1999-09-01 it started to +recommend it only for people who use Sun's compilers. + +Here are some workarounds to this problem: +@itemize @bullet +@item +Do not install Sun patch 107058-01 until after Sun releases a +complete patch for bug 4210064. This is the simplest course to take, +unless you must also use Sun's C compiler. Unfortunately 107058-01 +is preinstalled on some new Solaris 7-based hosts, so you may have to +back it out. + +@item +Copy the original, unpatched Solaris 7 +@command{/usr/ccs/bin/as} into +@command{/usr/local/libexec/gcc/sparc-sun-solaris2.7/3.4/as}, +adjusting the latter name to fit your local conventions and software +version numbers. + +@item +Install Sun patch 106950-03 (1999-05-25) or later. Nobody with +both 107058-01 and 106950-03 installed has reported the bug with GCC +and Sun's dynamic linker. This last course of action is riskiest, +for two reasons. First, you must install 106950 on all hosts that +run code generated by GCC; it doesn't suffice to install it only on +the hosts that run GCC itself. Second, Sun says that 106950-03 is +only a partial fix for bug 4210064, but Sun doesn't know whether the +partial fix is adequate for GCC@. Revision -08 or later should fix +the bug. The current (as of 2004-05-23) revision is -24, and is included in +the Solaris 7 Recommended Patch Cluster. +@end itemize + +GCC 3.3 triggers a bug in version 5.0 Alpha 03/27/98 of the Sun assembler, +which causes a bootstrap failure when linking the 64-bit shared version of +libgcc. A typical error message is: + +@smallexample +ld: fatal: relocation error: R_SPARC_32: file libgcc/sparcv9/_muldi3.o: + symbol <unknown>: offset 0xffffffff7ec133e7 is non-aligned. +@end smallexample + +This bug has been fixed in the final 5.0 version of the assembler. + +A similar problem was reported for version Sun WorkShop 6 99/08/18 of the +Sun assembler, which causes a bootstrap failure with GCC 4.0.0: + +@smallexample +ld: fatal: relocation error: R_SPARC_DISP32: + file .libs/libstdc++.lax/libsupc++convenience.a/vterminate.o: + symbol <unknown>: offset 0xfccd33ad is non-aligned +@end smallexample + +This bug has been fixed in more recent revisions of the assembler. + +@html +<hr /> +@end html +@heading @anchor{sparc-x-linux}sparc-*-linux* + +GCC versions 3.0 and higher require binutils 2.11.2 and glibc 2.2.4 +or newer on this platform. All earlier binutils and glibc +releases mishandled unaligned relocations on @code{sparc-*-*} targets. + + +@html +<hr /> +@end html +@heading @anchor{sparc64-x-solaris2}sparc64-*-solaris2* + +When configuring the GNU Multiple Precision Library (GMP) or the +MPFR library, the canonical target triplet must be specified as +the @command{build} parameter on the configure line. For example +on a Solaris 7 system: + +@smallexample + % ./configure --build=sparc64-sun-solaris2.7 --prefix=xxx +@end smallexample + +The following compiler flags must be specified in the configure +step in order to bootstrap this target with the Sun compiler: + +@smallexample + % CC="cc -xarch=v9 -xildoff" @var{srcdir}/configure [@var{options}] [@var{target}] +@end smallexample + +@option{-xarch=v9} specifies the SPARC-V9 architecture to the Sun toolchain +and @option{-xildoff} turns off the incremental linker. + +@html +<hr /> +@end html +@heading @anchor{sparcv9-x-solaris2}sparcv9-*-solaris2* + +This is a synonym for sparc64-*-solaris2*. + +@html +<hr /> +@end html +@heading @anchor{x-x-sysv}*-*-sysv* +On System V release 3, you may get this error message +while linking: + +@smallexample +ld fatal: failed to write symbol name @var{something} + in strings table for file @var{whatever} +@end smallexample + +This probably indicates that the disk is full or your ulimit won't allow +the file to be as large as it needs to be. + +This problem can also result because the kernel parameter @code{MAXUMEM} +is too small. If so, you must regenerate the kernel and make the value +much larger. The default value is reported to be 1024; a value of 32768 +is said to work. Smaller values may also work. + +On System V, if you get an error like this, + +@smallexample +/usr/local/lib/bison.simple: In function `yyparse': +/usr/local/lib/bison.simple:625: virtual memory exhausted +@end smallexample + +@noindent +that too indicates a problem with disk space, ulimit, or @code{MAXUMEM}. + +On a System V release 4 system, make sure @file{/usr/bin} precedes +@file{/usr/ucb} in @code{PATH}. The @command{cc} command in +@file{/usr/ucb} uses libraries which have bugs. + +@html +<hr /> +@end html +@heading @anchor{vax-dec-ultrix}vax-dec-ultrix +Don't try compiling with VAX C (@command{vcc}). It produces incorrect code +in some cases (for example, when @code{alloca} is used). + +@html +<hr /> +@end html +@heading @anchor{x-x-vxworks}*-*-vxworks* +Support for VxWorks is in flux. At present GCC supports @emph{only} the +very recent VxWorks 5.5 (aka Tornado 2.2) release, and only on PowerPC@. +We welcome patches for other architectures supported by VxWorks 5.5. +Support for VxWorks AE would also be welcome; we believe this is merely +a matter of writing an appropriate ``configlette'' (see below). We are +not interested in supporting older, a.out or COFF-based, versions of +VxWorks in GCC 3. + +VxWorks comes with an older version of GCC installed in +@file{@var{$WIND_BASE}/host}; we recommend you do not overwrite it. +Choose an installation @var{prefix} entirely outside @var{$WIND_BASE}. +Before running @command{configure}, create the directories @file{@var{prefix}} +and @file{@var{prefix}/bin}. Link or copy the appropriate assembler, +linker, etc.@: into @file{@var{prefix}/bin}, and set your @var{PATH} to +include that directory while running both @command{configure} and +@command{make}. + +You must give @command{configure} the +@option{--with-headers=@var{$WIND_BASE}/target/h} switch so that it can +find the VxWorks system headers. Since VxWorks is a cross compilation +target only, you must also specify @option{--target=@var{target}}. +@command{configure} will attempt to create the directory +@file{@var{prefix}/@var{target}/sys-include} and copy files into it; +make sure the user running @command{configure} has sufficient privilege +to do so. + +GCC's exception handling runtime requires a special ``configlette'' +module, @file{contrib/gthr_supp_vxw_5x.c}. Follow the instructions in +that file to add the module to your kernel build. (Future versions of +VxWorks will incorporate this module.) + +@html +<hr /> +@end html +@heading @anchor{x86-64-x-x}x86_64-*-*, amd64-*-* + +GCC supports the x86-64 architecture implemented by the AMD64 processor +(amd64-*-* is an alias for x86_64-*-*) on GNU/Linux, FreeBSD and NetBSD@. +On GNU/Linux the default is a bi-arch compiler which is able to generate +both 64-bit x86-64 and 32-bit x86 code (via the @option{-m32} switch). + +@html +<hr /> +@end html +@heading @anchor{xtensa-x-elf}xtensa-*-elf + +This target is intended for embedded Xtensa systems using the +@samp{newlib} C library. It uses ELF but does not support shared +objects. Designed-defined instructions specified via the +Tensilica Instruction Extension (TIE) language are only supported +through inline assembly. + +The Xtensa configuration information must be specified prior to +building GCC@. The @file{include/xtensa-config.h} header +file contains the configuration information. If you created your +own Xtensa configuration with the Xtensa Processor Generator, the +downloaded files include a customized copy of this header file, +which you can use to replace the default header file. + +@html +<hr /> +@end html +@heading @anchor{xtensa-x-linux}xtensa-*-linux* + +This target is for Xtensa systems running GNU/Linux. It supports ELF +shared objects and the GNU C library (glibc). It also generates +position-independent code (PIC) regardless of whether the +@option{-fpic} or @option{-fPIC} options are used. In other +respects, this target is the same as the +@uref{#xtensa-*-elf,,@samp{xtensa-*-elf}} target. + +@html +<hr /> +@end html +@heading @anchor{windows}Microsoft Windows (32-bit) + +Ports of GCC are included with the +@uref{http://www.cygwin.com/,,Cygwin environment}. + +GCC will build under Cygwin without modification; it does not build +with Microsoft's C++ compiler and there are no plans to make it do so. + +@html +<hr /> +@end html +@heading @anchor{os2}OS/2 + +GCC does not currently support OS/2. However, Andrew Zabolotny has been +working on a generic OS/2 port with pgcc. The current code can be found +at @uref{http://www.goof.com/pcg/os2/,,http://www.goof.com/pcg/os2/}. + +@html +<hr /> +@end html +@heading @anchor{older}Older systems + +GCC contains support files for many older (1980s and early +1990s) Unix variants. For the most part, support for these systems +has not been deliberately removed, but it has not been maintained for +several years and may suffer from bitrot. + +Starting with GCC 3.1, each release has a list of ``obsoleted'' systems. +Support for these systems is still present in that release, but +@command{configure} will fail unless the @option{--enable-obsolete} +option is given. Unless a maintainer steps forward, support for these +systems will be removed from the next release of GCC@. + +Support for old systems as hosts for GCC can cause problems if the +workarounds for compiler, library and operating system bugs affect the +cleanliness or maintainability of the rest of GCC@. In some cases, to +bring GCC up on such a system, if still possible with current GCC, may +require first installing an old version of GCC which did work on that +system, and using it to compile a more recent GCC, to avoid bugs in the +vendor compiler. Old releases of GCC 1 and GCC 2 are available in the +@file{old-releases} directory on the @uref{../mirrors.html,,GCC mirror +sites}. Header bugs may generally be avoided using +@command{fixincludes}, but bugs or deficiencies in libraries and the +operating system may still cause problems. + +Support for older systems as targets for cross-compilation is less +problematic than support for them as hosts for GCC; if an enthusiast +wishes to make such a target work again (including resurrecting any of +the targets that never worked with GCC 2, starting from the last +version before they were removed), patches +@uref{../contribute.html,,following the usual requirements} would be +likely to be accepted, since they should not affect the support for more +modern targets. + +For some systems, old versions of GNU binutils may also be useful, +and are available from @file{pub/binutils/old-releases} on +@uref{http://sourceware.org/mirrors.html,,sourceware.org mirror sites}. + +Some of the information on specific systems above relates to +such older systems, but much of the information +about GCC on such systems (which may no longer be applicable to +current GCC) is to be found in the GCC texinfo manual. + +@html +<hr /> +@end html +@heading @anchor{elf}all ELF targets (SVR4, Solaris 2, etc.) + +C++ support is significantly better on ELF targets if you use the +@uref{./configure.html#with-gnu-ld,,GNU linker}; duplicate copies of +inlines, vtables and template instantiations will be discarded +automatically. + + +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***Old documentation****************************************************** +@ifset oldhtml +@include install-old.texi +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c ***GFDL******************************************************************** +@ifset gfdlhtml +@include fdl.texi +@html +<hr /> +<p> +@end html +@ifhtml +@uref{./index.html,,Return to the GCC Installation page} +@end ifhtml +@end ifset + +@c *************************************************************************** +@c Part 6 The End of the Document +@ifinfo +@comment node-name, next, previous, up +@node Concept Index, , GNU Free Documentation License, Top +@end ifinfo + +@ifinfo +@unnumbered Concept Index + +@printindex cp + +@contents +@end ifinfo +@bye diff --git a/gcc-4.2.1-5666.3/gcc/doc/install.texi2html b/gcc-4.2.1-5666.3/gcc/doc/install.texi2html new file mode 100755 index 000000000..44da873b7 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/install.texi2html @@ -0,0 +1,33 @@ +#!/bin/sh +# +# Convert the GCC install documentation from texinfo format to HTML. +# +# $SOURCEDIR and $DESTDIR, resp., refer to the directory containing +# the texinfo source and the directory to put the HTML version in. +# +# (C) 2001, 2003, 2006 Free Software Foundation +# Originally by Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>, June 2001. +# +# This script is Free Software, and it can be copied, distributed and +# modified as defined in the GNU General Public License. A copy of +# its license can be downloaded from http://www.gnu.org/copyleft/gpl.html + +set -e + +SOURCEDIR=${SOURCEDIR-.} +DESTDIR=${DESTDIR-HTML} + +MAKEINFO=${MAKEINFO-makeinfo} + +if [ ! -d $DESTDIR ]; then + mkdir -p $DESTDIR +fi + +for x in index.html specific.html prerequisites.html download.html configure.html \ + build.html test.html finalinstall.html binaries.html old.html \ + gfdl.html +do + define=`echo $x | sed -e 's/\.//g'` + echo "define = $define" + $MAKEINFO -I $SOURCEDIR -I $SOURCEDIR/include $SOURCEDIR/install.texi --html --no-split -D$define -o$DESTDIR/$x +done diff --git a/gcc-4.2.1-5666.3/gcc/doc/interface.texi b/gcc-4.2.1-5666.3/gcc/doc/interface.texi new file mode 100644 index 000000000..f6fdc329e --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/interface.texi @@ -0,0 +1,71 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Interface +@chapter Interfacing to GCC Output +@cindex interfacing to GCC output +@cindex run-time conventions +@cindex function call conventions +@cindex conventions, run-time + +GCC is normally configured to use the same function calling convention +normally in use on the target system. This is done with the +machine-description macros described (@pxref{Target Macros}). + +@cindex unions, returning +@cindex structures, returning +@cindex returning structures and unions +However, returning of structure and union values is done differently on +some target machines. As a result, functions compiled with PCC +returning such types cannot be called from code compiled with GCC, +and vice versa. This does not cause trouble often because few Unix +library routines return structures or unions. + +GCC code returns structures and unions that are 1, 2, 4 or 8 bytes +long in the same registers used for @code{int} or @code{double} return +values. (GCC typically allocates variables of such types in +registers also.) Structures and unions of other sizes are returned by +storing them into an address passed by the caller (usually in a +register). The target hook @code{TARGET_STRUCT_VALUE_RTX} +tells GCC where to pass this address. + +By contrast, PCC on most target machines returns structures and unions +of any size by copying the data into an area of static storage, and then +returning the address of that storage as if it were a pointer value. +The caller must copy the data from that memory area to the place where +the value is wanted. This is slower than the method used by GCC, and +fails to be reentrant. + +On some target machines, such as RISC machines and the 80386, the +standard system convention is to pass to the subroutine the address of +where to return the value. On these machines, GCC has been +configured to be compatible with the standard compiler, when this method +is used. It may not be compatible for structures of 1, 2, 4 or 8 bytes. + +@cindex argument passing +@cindex passing arguments +GCC uses the system's standard convention for passing arguments. On +some machines, the first few arguments are passed in registers; in +others, all are passed on the stack. It would be possible to use +registers for argument passing on any machine, and this would probably +result in a significant speedup. But the result would be complete +incompatibility with code that follows the standard convention. So this +change is practical only if you are switching to GCC as the sole C +compiler for the system. We may implement register argument passing on +certain machines once we have a complete GNU system so that we can +compile the libraries with GCC@. + +On some machines (particularly the SPARC), certain types of arguments +are passed ``by invisible reference''. This means that the value is +stored in memory, and the address of the memory location is passed to +the subroutine. + +@cindex @code{longjmp} and automatic variables +If you use @code{longjmp}, beware of automatic variables. ISO C says that +automatic variables that are not declared @code{volatile} have undefined +values after a @code{longjmp}. And this is all GCC promises to do, +because it is very difficult to restore register variables correctly, and +one of GCC's features is that it can put variables in registers without +your asking it to. diff --git a/gcc-4.2.1-5666.3/gcc/doc/invoke.texi b/gcc-4.2.1-5666.3/gcc/doc/invoke.texi new file mode 100644 index 000000000..f8f81b46d --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/invoke.texi @@ -0,0 +1,15136 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, +@c 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@ignore +@c man begin INCLUDE +@include gcc-vers.texi +@c man end + +@c man begin COPYRIGHT +Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with the +Invariant Sections being ``GNU General Public License'' and ``Funding +Free Software'', the Front-Cover texts being (a) (see below), and with +the Back-Cover Texts being (b) (see below). A copy of the license is +included in the gfdl(7) man page. + +(a) The FSF's Front-Cover Text is: + + A GNU Manual + +(b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. +@c man end +@c Set file name and title for the man page. +@setfilename gcc +@settitle GNU project C and C++ compiler +@c man begin SYNOPSIS +gcc [@option{-c}|@option{-S}|@option{-E}] [@option{-std=}@var{standard}] + [@option{-g}] [@option{-pg}] [@option{-O}@var{level}] + [@option{-W}@var{warn}@dots{}] [@option{-pedantic}] + [@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}] + [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}] + [@option{-f}@var{option}@dots{}] [@option{-m}@var{machine-option}@dots{}] + [@option{-o} @var{outfile}] [@@@var{file}] @var{infile}@dots{} + +Only the most useful options are listed here; see below for the +remainder. @samp{g++} accepts mostly the same options as @samp{gcc}. + +@c APPLE LOCAL begin manual +In Apple's version of GCC, both @samp{cc} and @samp{gcc} are actually +symbolic links to a compiler named like gcc-@var{version}. +Similarly, @samp{c++} and @samp{g++} are links to a compiler named like +g++-@var{version}. + +Note that Apple's GCC includes a number of extensions to standard GCC +(flagged below with ``APPLE ONLY''), and that not all generic GCC +options are available or supported on Darwin / Mac OS X. In particular, +Apple does not currently support the compilation of Fortran, Ada, or +Java, although there are third parties who have made these work. +@c APPLE LOCAL end manual + +@c man end +@c man begin SEEALSO +gpl(7), gfdl(7), fsf-funding(7), +cpp(1), gcov(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1) +and the Info entries for @file{gcc}, @file{cpp}, @file{as}, +@file{ld}, @file{binutils} and @file{gdb}. +@c man end +@c man begin BUGS +@c APPLE LOCAL begin Apple bug-report +To report bugs to Apple, see +@w{@uref{http://developer.apple.com/bugreporter}}. +@c APPLE LOCAL end Apple bug-report +@c man end +@c man begin AUTHOR +See the Info entry for @command{gcc}, or +@w{@uref{http://gcc.gnu.org/onlinedocs/gcc/Contributors.html}}, +for contributors to GCC@. +@c man end +@end ignore + +@node Invoking GCC +@chapter GCC Command Options +@cindex GCC command options +@cindex command options +@cindex options, GCC command + +@c man begin DESCRIPTION +When you invoke GCC, it normally does preprocessing, compilation, +assembly and linking. The ``overall options'' allow you to stop this +process at an intermediate stage. For example, the @option{-c} option +says not to run the linker. Then the output consists of object files +output by the assembler. + +Other options are passed on to one stage of processing. Some options +control the preprocessor and others the compiler itself. Yet other +options control the assembler and linker; most of these are not +documented here, since you rarely need to use any of them. + +@cindex C compilation options +Most of the command line options that you can use with GCC are useful +for C programs; when an option is only useful with another language +(usually C++), the explanation says so explicitly. If the description +for a particular option does not mention a source language, you can use +that option with all supported languages. + +@cindex C++ compilation options +@xref{Invoking G++,,Compiling C++ Programs}, for a summary of special +options for compiling C++ programs. + +@cindex grouping options +@cindex options, grouping +The @command{gcc} program accepts options and file names as operands. Many +options have multi-letter names; therefore multiple single-letter options +may @emph{not} be grouped: @option{-dr} is very different from @w{@samp{-d +-r}}. + +@cindex order of options +@cindex options, order +You can mix options and other arguments. For the most part, the order +you use doesn't matter. Order does matter when you use several options +of the same kind; for example, if you specify @option{-L} more than once, +the directories are searched in the order specified. + +Many options have long names starting with @samp{-f} or with +@samp{-W}---for example, +@option{-fmove-loop-invariants}, @option{-Wformat} and so on. Most of +these have both positive and negative forms; the negative form of +@option{-ffoo} would be @option{-fno-foo}. This manual documents +only one of these two forms, whichever one is not the default. + +@c man end + +@xref{Option Index}, for an index to GCC's options. + +@menu +* Option Summary:: Brief list of all options, without explanations. +* Overall Options:: Controlling the kind of output: + an executable, object files, assembler files, + or preprocessed source. +* Invoking G++:: Compiling C++ programs. +* C Dialect Options:: Controlling the variant of C language compiled. +* C++ Dialect Options:: Variations on C++. +* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C + and Objective-C++. +* Language Independent Options:: Controlling how diagnostics should be + formatted. +* Warning Options:: How picky should the compiler be? +* Debugging Options:: Symbol tables, measurements, and debugging dumps. +* Optimize Options:: How much optimization? +* Preprocessor Options:: Controlling header files and macro definitions. + Also, getting dependency information for Make. +* Assembler Options:: Passing options to the assembler. +* Link Options:: Specifying libraries and so on. +* Directory Options:: Where to find header files and libraries. + Where to find the compiler executable files. +* Spec Files:: How to pass switches to sub-processes. +* Target Options:: Running a cross-compiler, or an old version of GCC. +* Submodel Options:: Specifying minor hardware or convention variations, + such as 68010 vs 68020. +* Code Gen Options:: Specifying conventions for function calls, data layout + and register usage. +* Environment Variables:: Env vars that affect GCC. +* Precompiled Headers:: Compiling a header once, and using it many times. +* Running Protoize:: Automatically adding or removing function prototypes. +@end menu + +@c man begin OPTIONS + +@node Option Summary +@section Option Summary + +Here is a summary of all the options, grouped by type. Explanations are +in the following sections. + +@table @emph +@item Overall Options +@xref{Overall Options,,Options Controlling the Kind of Output}. +@gccoptlist{-c -S -E -o @var{file} -combine -pipe -pass-exit-codes @gol +@c APPLE LOCAL -ObjC 2001-08-03 --sts ** +-ObjC (APPLE ONLY) -ObjC++ (APPLE ONLY) @gol +@c APPLE LOCAL begin fat builds +-arch @var{arch} (APPLE ONLY) @gol +-Xarch_@var{arch} @var{option} (APPLE ONLY) @gol +@c APPLE LOCAL end fat builds +@c APPLE LOCAL ss2 +-fsave-repository=@var{file} @gol +-x @var{language} -v -### --help --target-help --version @@@var{file}} + +@item C Language Options +@xref{C Dialect Options,,Options Controlling C Dialect}. +@gccoptlist{-ansi -std=@var{standard} -fgnu89-inline @gol +-aux-info @var{filename} @gol +@c APPLE LOCAL AltiVec +-faltivec (APPLE ONLY) @gol +@c APPLE LOCAL CW asm blocks +-fasm-blocks (APPLE ONLY) @gol +@c APPLE LOCAL blocks 7205047 5811887 +-fno-asm -fno-blocks -fno-builtin -fno-builtin-@var{function} @gol +-fhosted -ffreestanding -fopenmp -fms-extensions @gol +-trigraphs -no-integrated-cpp -traditional -traditional-cpp @gol +@c APPLE LOCAL 5612787 sse4 +-fallow-single-precision -fcond-mismatch -flax-vector-conversions @gol +@c APPLE LOCAL constant cfstrings --mrs +-fconstant-cfstrings (APPLE ONLY) @gol +@c APPLE LOCAL non lvalue assign +-fnon-lvalue-assign (APPLE ONLY) @gol +@c APPLE LOCAL nested functions 4357979 */ +-fno-nested-functions @gol +@c APPLE LOCAL pch distcc --mrs +-fpch-preprocess (APPLE ONLY) @gol +-fsigned-bitfields -fsigned-char @gol +@c APPLE LOCAL -Wno-#warnings +-Wno-#warnings (APPLE ONLY) @gol +@c APPLE LOCAL -Wextra-tokens 2001-08-02 --sts ** +-Wextra-tokens (APPLE ONLY) @gol +@c APPLE LOCAL -Wnewline-eof 2001-08-23 --sts ** +-Wnewline-eof (APPLE ONLY) @gol +@c APPLE LOCAL -Wno-altivec-long-deprecated --ilr ** +-Wno-altivec-long-deprecated (APPLE ONLY) +@c APPLE LOCAL begin 5695218 +-fglobal-alloc-prefer-bytes (APPLE ONLY) +-fno-global-alloc-prefer-bytes (APPLE ONLY) +@c APPLE LOCAL end 5695218 +@c APPLE LOCAL fwritable strings +-funsigned-bitfields -funsigned-char -fwritable-strings} + +@item C++ Language Options +@xref{C++ Dialect Options,,Options Controlling C++ Dialect}. +@gccoptlist{-fabi-version=@var{n} -fno-access-control -fcheck-new @gol +-fconserve-space -ffriend-injection @gol +-fno-elide-constructors @gol +-fno-enforce-eh-specs @gol +-ffor-scope -fno-for-scope -fno-gnu-keywords @gol +-fno-implicit-templates @gol +-fno-implicit-inline-templates @gol +-fno-implement-inlines -fms-extensions @gol +-fno-nonansi-builtins -fno-operator-names @gol +-fno-optional-diags -fpermissive @gol +-frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol +-fno-threadsafe-statics -fuse-cxa-atexit -fno-weak -nostdinc++ @gol +-fno-default-inline -fvisibility-inlines-hidden @gol +@c APPLE LOCAL mainline 2007-06-28 ms tinfo compat 4230099 +-fvisibility-ms-compat +-Wabi -Wctor-dtor-privacy @gol +-Wnon-virtual-dtor -Wreorder @gol +-Weffc++ -Wno-deprecated -Wstrict-null-sentinel @gol +-Wno-non-template-friend -Wold-style-cast @gol +-Woverloaded-virtual -Wno-pmf-conversions @gol +-Wsign-promo} + +@item Objective-C and Objective-C++ Language Options +@xref{Objective-C and Objective-C++ Dialect Options,,Options Controlling +Objective-C and Objective-C++ Dialects}. +@gccoptlist{-fconstant-string-class=@var{class-name} @gol +-fgnu-runtime -fnext-runtime @gol +-fno-nil-receivers @gol +-fobjc-call-cxx-cdtors @gol +-fobjc-direct-dispatch @gol +@c APPLE LOCAL radar 4512786 +-fobjc-sjlj-exceptions @gol +-fobjc-gc @gol +-freplace-objc-classes @gol +-fzero-link @gol +-gen-decls @gol +-Wassign-intercept @gol +-Wno-protocol -Wselector @gol +@c APPLE LOCAL radar 5172645 +-Wno-property-assign-default @gol +-Wstrict-selector-match @gol +-Wundeclared-selector} + +@item Language Independent Options +@xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}. +@gccoptlist{-fmessage-length=@var{n} @gol +-fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]} @gol +-fdiagnostics-show-option} + +@item Warning Options +@xref{Warning Options,,Options to Request or Suppress Warnings}. +@gccoptlist{-fsyntax-only -pedantic -pedantic-errors @gol +-w -Wextra -Wall -Waddress -Waggregate-return -Wno-attributes @gol +-Wc++-compat -Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment @gol +-Wconversion -Wno-deprecated-declarations @gol +-Wdisabled-optimization -Wno-div-by-zero -Wno-endif-labels @gol +-Werror -Werror=* -Werror-implicit-function-declaration @gol +@c APPLE LOCAL default to Wformat-security 5764921 +-Wfatal-errors -Wfloat-equal -Wno-format -Wformat=2 @gol +-Wno-format-extra-args -Wformat-nonliteral @gol +@c APPLE LOCAL default to Wformat-security 5764921 +-Wno-format-security -Wformat-y2k @gol +@c APPLE LOCAL Wglobal-constructors 6324584 +-Wglobal-constructors @gol +-Wimplicit -Wimplicit-function-declaration -Wimplicit-int @gol +-Wimport -Wno-import -Winit-self -Winline @gol +-Wno-int-to-pointer-cast @gol +-Wno-invalid-offsetof -Winvalid-pch @gol +-Wlarger-than-@var{len} -Wunsafe-loop-optimizations -Wlong-long @gol +-Wmain -Wmissing-braces -Wmissing-field-initializers @gol +-Wmissing-format-attribute -Wmissing-include-dirs @gol +-Wmissing-noreturn @gol +@c APPLE LOCAL warn missing prototype 6261539 +-Wmissing-prototypes @gol +@c APPLE LOCAL -Wmost +-Wmost (APPLE ONLY) @gol +-Wno-multichar -Wnonnull -Wno-overflow @gol +-Woverlength-strings -Wpacked -Wpadded @gol +-Wparentheses -Wpointer-arith -Wno-pointer-to-int-cast @gol +-Wredundant-decls @gol +-Wreturn-type -Wsequence-point -Wshadow @gol +-Wsign-compare -Wstack-protector @gol +-Wstrict-aliasing -Wstrict-aliasing=2 @gol +-Wstrict-overflow -Wstrict-overflow=@var{n} @gol +-Wswitch -Wswitch-default -Wswitch-enum @gol +-Wsystem-headers -Wtrigraphs -Wundef -Wuninitialized @gol +-Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol +-Wunused -Wunused-function -Wunused-label -Wunused-parameter @gol +-Wunused-value -Wunused-variable -Wvariadic-macros @gol +-Wvolatile-register-var -Wwrite-strings} + +@c APPLE LOCAL begin -Wdiscard-qual 4086969 +@item C-only Warning Options +@gccoptlist{-Wbad-function-cast -Wmissing-declarations @gol +@c APPLE LOCAL warn missing prototype 6261539 +-Wnested-externs -Wold-style-definition @gol +-Wstrict-prototypes -Wtraditional @gol +-Wdeclaration-after-statement -Wno-discard-qual -Wno-pointer-sign} +@c APPLE LOCAL end -Wdiscard-qual 4086969 + +@item Debugging Options +@xref{Debugging Options,,Options for Debugging Your Program or GCC}. +@gccoptlist{-d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol +-fdump-noaddr -fdump-unnumbered -fdump-translation-unit@r{[}-@var{n}@r{]} @gol +-fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol +-fdump-ipa-all -fdump-ipa-cgraph @gol +-fdump-tree-all @gol +-fdump-tree-original@r{[}-@var{n}@r{]} @gol +-fdump-tree-optimized@r{[}-@var{n}@r{]} @gol +-fdump-tree-inlined@r{[}-@var{n}@r{]} @gol +-fdump-tree-cfg -fdump-tree-vcg -fdump-tree-alias @gol +-fdump-tree-ch @gol +-fdump-tree-ssa@r{[}-@var{n}@r{]} -fdump-tree-pre@r{[}-@var{n}@r{]} @gol +-fdump-tree-ccp@r{[}-@var{n}@r{]} -fdump-tree-dce@r{[}-@var{n}@r{]} @gol +-fdump-tree-gimple@r{[}-raw@r{]} -fdump-tree-mudflap@r{[}-@var{n}@r{]} @gol +-fdump-tree-dom@r{[}-@var{n}@r{]} @gol +-fdump-tree-dse@r{[}-@var{n}@r{]} @gol +-fdump-tree-phiopt@r{[}-@var{n}@r{]} @gol +-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol +-fdump-tree-copyrename@r{[}-@var{n}@r{]} @gol +-fdump-tree-nrv -fdump-tree-vect @gol +-fdump-tree-sink @gol +-fdump-tree-sra@r{[}-@var{n}@r{]} @gol +-fdump-tree-salias @gol +-fdump-tree-fre@r{[}-@var{n}@r{]} @gol +-fdump-tree-vrp@r{[}-@var{n}@r{]} @gol +-ftree-vectorizer-verbose=@var{n} @gol +-fdump-tree-storeccp@r{[}-@var{n}@r{]} @gol +@c APPLE LOCAL 4167759 +-flimit-debug-info @gol +-feliminate-dwarf2-dups -feliminate-unused-debug-types @gol +-feliminate-unused-debug-symbols -femit-class-debug-always @gol +@c APPLE LOCAL opt diary +-fmem-report -fopt-diary -fprofile-arcs @gol +-frandom-seed=@var{string} -fsched-verbose=@var{n} @gol +-ftest-coverage -ftime-report -fvar-tracking @gol +-g -g@var{level} -gcoff -gdwarf-2 @gol +-ggdb -gstabs -gstabs+ -gvms -gxcoff -gxcoff+ @gol +-p -pg -print-file-name=@var{library} -print-libgcc-file-name @gol +-print-multi-directory -print-multi-lib @gol +-print-prog-name=@var{program} -print-search-dirs -Q @gol +-save-temps -time} + +@item Optimization Options +@xref{Optimize Options,,Options that Control Optimization}. +@gccoptlist{-falign-functions=@var{n} -falign-jumps=@var{n} @gol +-falign-labels=@var{n} -falign-loops=@var{n} @gol +@c APPLE LOCAL -falign-loops-max-skip +-falign-loops-max-skip=@var{n} -falign-jumps-max-skip=@var{n} @gol +-fbounds-check -fmudflap -fmudflapth -fmudflapir @gol +-fbranch-probabilities -fprofile-values -fvpt -fbranch-target-load-optimize @gol +-fbranch-target-load-optimize2 -fbtr-bb-exclusive @gol +@c APPLE LOCAL add fcreate-profile +-fcaller-saves -fcprop-registers -fcreate-profile -fcse-follow-jumps @gol +-fcse-skip-blocks -fcx-limited-range -fdata-sections @gol +-fdelayed-branch -fdelete-null-pointer-checks -fearly-inlining @gol +-fexpensive-optimizations -ffast-math -ffloat-store @gol +-fforce-addr -ffunction-sections @gol +-fgcse -fgcse-lm -fgcse-sm -fgcse-las -fgcse-after-reload @gol +-fcrossjumping -fif-conversion -fif-conversion2 @gol +-finline-functions -finline-functions-called-once @gol +-finline-limit=@var{n} -fkeep-inline-functions @gol +@c APPLE LOCAL begin ARM conditionally disable local RA +-fkeep-static-consts @gol +-flocal-alloc (APPLE ONLY) @gol +-fmerge-constants -fmerge-all-constants @gol +@c APPLE LOCAL end ARM conditionally disable local RA +-fmodulo-sched -fno-branch-count-reg @gol +-fno-default-inline -fno-defer-pop -fmove-loop-invariants @gol +-fno-function-cse -fno-guess-branch-probability @gol +-fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol +-funsafe-math-optimizations -funsafe-loop-optimizations -ffinite-math-only @gol +-fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol +@c APPLE LOCAL 4356747 stack realign +-mstackrealign @gol +-fomit-frame-pointer -foptimize-register-move @gol +-foptimize-sibling-calls -fprefetch-loop-arrays @gol +-fprofile-generate -fprofile-use @gol +-fregmove -frename-registers @gol +-freorder-blocks -freorder-blocks-and-partition -freorder-functions @gol +-frerun-cse-after-loop @gol +-frounding-math -frtl-abstract-sequences @gol +-fschedule-insns -fschedule-insns2 @gol +-fno-sched-interblock -fno-sched-spec -fsched-spec-load @gol +-fsched-spec-load-dangerous @gol +-fsched-stalled-insns=@var{n} -fsched-stalled-insns-dep=@var{n} @gol +-fsched2-use-superblocks @gol +-fsched2-use-traces -fsee -freschedule-modulo-scheduled-loops @gol +-fsection-anchors -fsignaling-nans -fsingle-precision-constant @gol +-fstack-protector -fstack-protector-all @gol +-fstrict-aliasing -fstrict-overflow -ftracer -fthread-jumps @gol +-funroll-all-loops -funroll-loops -fpeel-loops @gol +-fsplit-ivs-in-unroller -funswitch-loops @gol +-fvariable-expansion-in-unroller @gol +-ftree-pre -ftree-ccp -ftree-dce -ftree-loop-optimize @gol +-ftree-loop-linear -ftree-loop-im -ftree-loop-ivcanon -fivopts @gol +-ftree-dominator-opts -ftree-dse -ftree-copyrename -ftree-sink @gol +-ftree-ch -ftree-sra -ftree-ter -ftree-lrs -ftree-fre -ftree-vectorize @gol +@c APPLE LOCAL add fuse-profile +-ftree-vect-loop-version -ftree-salias -fuse-profile -fipa-pta -fweb @gol +-ftree-copy-prop -ftree-store-ccp -ftree-store-copy-prop -fwhole-program @gol +--param @var{name}=@var{value} +@c APPLE LOCAL -fast, -Oz +-O -O0 -O1 -O2 -O3 -Os -Oz (APPLE ONLY) -fast (APPLE ONLY)} + +@item Preprocessor Options +@xref{Preprocessor Options,,Options Controlling the Preprocessor}. +@gccoptlist{-A@var{question}=@var{answer} @gol +-A-@var{question}@r{[}=@var{answer}@r{]} @gol +-C -dD -dI -dM -dN @gol +-D@var{macro}@r{[}=@var{defn}@r{]} -E -H @gol +-idirafter @var{dir} @gol +-include @var{file} -imacros @var{file} @gol +-iprefix @var{file} -iwithprefix @var{dir} @gol +-iwithprefixbefore @var{dir} -isystem @var{dir} @gol +-imultilib @var{dir} -isysroot @var{dir} @gol +@c APPLE LOCAL ARM iwithsysroot 4917039 +-iwithsysroot (APPLE ONLY) @var{dir} @gol +-M -MM -MF -MG -MP -MQ -MT -nostdinc @gol +-P -fworking-directory -remap @gol +-trigraphs -undef -U@var{macro} -Wp,@var{option} @gol +-Xpreprocessor @var{option}} + +@item Assembler Option +@xref{Assembler Options,,Passing Options to the Assembler}. +@gccoptlist{-Wa,@var{option} -Xassembler @var{option}} + +@item Linker Options +@xref{Link Options,,Options for Linking}. +@gccoptlist{@var{object-file-name} -l@var{library} @gol +-nostartfiles -nodefaultlibs -nostdlib -pie -rdynamic @gol +-s -static -static-libgcc -shared -shared-libgcc -symbolic @gol +-Wl,@var{option} -Xlinker @var{option} @gol +-u @var{symbol}} + +@item Directory Options +@xref{Directory Options,,Options for Directory Search}. +@gccoptlist{-B@var{prefix} -I@var{dir} -iquote@var{dir} -L@var{dir} +-specs=@var{file} -I- --sysroot=@var{dir}} + +@item Target Options +@c I wrote this xref this way to avoid overfull hbox. -- rms +@xref{Target Options}. +@gccoptlist{-V @var{version} -b @var{machine}} + +@item Machine Dependent Options +@xref{Submodel Options,,Hardware Models and Configurations}. +@c This list is ordered alphanumerically by subsection name. +@c Try and put the significant identifier (CPU or system) first, +@c so users have a clue at guessing where the ones they want will be. + +@c APPLE LOCAL prune man page +@ignore +@emph{ARC Options} +@gccoptlist{-EB -EL @gol +-mmangle-cpu -mcpu=@var{cpu} -mtext=@var{text-section} @gol +-mdata=@var{data-section} -mrodata=@var{readonly-data-section}} +@c APPLE LOCAL ARM prune man page +@end ignore + +@emph{ARM Options} +@gccoptlist{-mapcs-frame -mno-apcs-frame @gol +-mabi=@var{name} @gol +-mapcs-stack-check -mno-apcs-stack-check @gol +-mapcs-float -mno-apcs-float @gol +-mapcs-reentrant -mno-apcs-reentrant @gol +-msched-prolog -mno-sched-prolog @gol +-mlittle-endian -mbig-endian -mwords-little-endian @gol +-mfloat-abi=@var{name} -msoft-float -mhard-float -mfpe @gol +-mthumb-interwork -mno-thumb-interwork @gol +-mcpu=@var{name} -march=@var{name} -mfpu=@var{name} @gol +-mstructure-size-boundary=@var{n} @gol +-mabort-on-noreturn @gol +-mlong-calls -mno-long-calls @gol +-msingle-pic-base -mno-single-pic-base @gol +-mpic-register=@var{reg} @gol +-mnop-fun-dllimport @gol +-mcirrus-fix-invalid-insns -mno-cirrus-fix-invalid-insns @gol +-mpoke-function-name @gol +-mthumb -marm @gol +-mtpcs-frame -mtpcs-leaf-frame @gol +-mcaller-super-interworking -mcallee-super-interworking @gol +@c APPLE LOCAL begin 5946347 ms_struct support +-mtp=@var{name} @gol +-mms-bitfields -mno-ms-bitfields} +@c APPLE LOCAL end 5946347 ms_struct support + +@c APPLE LOCAL ARM prune man page +@ignore +@emph{AVR Options} +@gccoptlist{-mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts @gol +-mcall-prologues -mno-tablejump -mtiny-stack -mint8} + +@emph{Blackfin Options} +@gccoptlist{-momit-leaf-frame-pointer -mno-omit-leaf-frame-pointer @gol +-mspecld-anomaly -mno-specld-anomaly -mcsync-anomaly -mno-csync-anomaly @gol +-mlow-64k -mno-low64k -mid-shared-library @gol +-mno-id-shared-library -mshared-library-id=@var{n} @gol +-mlong-calls -mno-long-calls} + +@emph{CRIS Options} +@gccoptlist{-mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol +-mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol +-metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol +-mstack-align -mdata-align -mconst-align @gol +-m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol +-melf -maout -melinux -mlinux -sim -sim2 @gol +-mmul-bug-workaround -mno-mul-bug-workaround} +@c APPLE LOCAL prune man page +@end ignore + +@emph{CRX Options} +@gccoptlist{-mmac -mpush-args} + +@emph{Darwin Options} +@gccoptlist{-all_load -allowable_client -arch -arch_errors_fatal @gol +-arch_only -bind_at_load -bundle -bundle_loader @gol +-client_name -compatibility_version -current_version @gol +-dead_strip @gol +-dependency-file -dylib_file -dylinker_install_name @gol +-dynamic -dynamiclib -exported_symbols_list @gol +-filelist -flat_namespace -force_cpusubtype_ALL @gol +@c APPLE LOCAL 7519550 force local +-force_flat_namespace -force_load -headerpad_max_install_names @gol +@c APPLE LOCAL iframework for 4.3 4094959 +-iframework @gol +-image_base -init -install_name -keep_private_externs @gol +-multi_module -multiply_defined -multiply_defined_unused @gol +-noall_load -no_dead_strip_inits_and_terms @gol +-nofixprebinding -nomultidefs -noprebind -noseglinkedit @gol +-pagezero_size -prebind -prebind_all_twolevel_modules @gol +-private_bundle -read_only_relocs -sectalign @gol +-sectobjectsymbols -whyload -seg1addr @gol +-sectcreate -sectobjectsymbols -sectorder @gol +-segaddr -segs_read_only_addr -segs_read_write_addr @gol +-seg_addr_table -seg_addr_table_filename -seglinkedit @gol +-segprot -segs_read_only_addr -segs_read_write_addr @gol +-single_module -static -sub_library -sub_umbrella @gol +-twolevel_namespace -umbrella -undefined @gol +-unexported_symbols_list -weak_reference_mismatches @gol +-whatsloaded -F -gused -gfull -mmacosx-version-min=@var{version} @gol +@c APPLE LOCAL ARM 5905142 +-miphoneos-version-min=@var{version} @gol +@c APPLE LOCAL pascal strings +-mpascal-strings (APPLE ONLY) @gol +@c APPLE LOCAL begin fat builds +-mkernel -mone-byte-bool @gol +-Xarch_@var{arch}} +@c APPLE LOCAL end fat builds + +@c APPLE LOCAL prune man page +@ignore +@emph{DEC Alpha Options} +@gccoptlist{-mno-fp-regs -msoft-float -malpha-as -mgas @gol +-mieee -mieee-with-inexact -mieee-conformant @gol +-mfp-trap-mode=@var{mode} -mfp-rounding-mode=@var{mode} @gol +-mtrap-precision=@var{mode} -mbuild-constants @gol +-mcpu=@var{cpu-type} -mtune=@var{cpu-type} @gol +-mbwx -mmax -mfix -mcix @gol +-mfloat-vax -mfloat-ieee @gol +-mexplicit-relocs -msmall-data -mlarge-data @gol +-msmall-text -mlarge-text @gol +-mmemory-latency=@var{time}} + +@emph{DEC Alpha/VMS Options} +@gccoptlist{-mvms-return-codes} + +@emph{FRV Options} +@gccoptlist{-mgpr-32 -mgpr-64 -mfpr-32 -mfpr-64 @gol +-mhard-float -msoft-float @gol +-malloc-cc -mfixed-cc -mdword -mno-dword @gol +-mdouble -mno-double @gol +-mmedia -mno-media -mmuladd -mno-muladd @gol +-mfdpic -minline-plt -mgprel-ro -multilib-library-pic @gol +-mlinked-fp -mlong-calls -malign-labels @gol +-mlibrary-pic -macc-4 -macc-8 @gol +-mpack -mno-pack -mno-eflags -mcond-move -mno-cond-move @gol +-moptimize-membar -mno-optimize-membar @gol +-mscc -mno-scc -mcond-exec -mno-cond-exec @gol +-mvliw-branch -mno-vliw-branch @gol +-mmulti-cond-exec -mno-multi-cond-exec -mnested-cond-exec @gol +-mno-nested-cond-exec -mtomcat-stats @gol +-mTLS -mtls @gol +-mcpu=@var{cpu}} + +@emph{GNU/Linux Options} +@gccoptlist{-muclibc} + +@emph{H8/300 Options} +@gccoptlist{-mrelax -mh -ms -mn -mint32 -malign-300} + +@emph{HPPA Options} +@gccoptlist{-march=@var{architecture-type} @gol +-mbig-switch -mdisable-fpregs -mdisable-indexing @gol +-mfast-indirect-calls -mgas -mgnu-ld -mhp-ld @gol +-mfixed-range=@var{register-range} @gol +-mjump-in-delay -mlinker-opt -mlong-calls @gol +-mlong-load-store -mno-big-switch -mno-disable-fpregs @gol +-mno-disable-indexing -mno-fast-indirect-calls -mno-gas @gol +-mno-jump-in-delay -mno-long-load-store @gol +-mno-portable-runtime -mno-soft-float @gol +-mno-space-regs -msoft-float -mpa-risc-1-0 @gol +-mpa-risc-1-1 -mpa-risc-2-0 -mportable-runtime @gol +-mschedule=@var{cpu-type} -mspace-regs -msio -mwsio @gol +-munix=@var{unix-std} -nolibdld -static -threads} +@c APPLE LOCAL prune man page +@end ignore + +@emph{i386 and x86-64 Options} +@gccoptlist{-mtune=@var{cpu-type} -march=@var{cpu-type} @gol +-mfpmath=@var{unit} @gol +-masm=@var{dialect} -mno-fancy-math-387 @gol +-mno-fp-ret-in-387 -msoft-float -msvr3-shlib @gol +-mno-wide-multiply -mrtd -malign-double @gol +-mpreferred-stack-boundary=@var{num} @gol +@c APPLE LOCAL begin 5612787 sse4 +-mmmx -msse -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -msse4a @gol +@c APPLE LOCAL end 5612787 sse4 +-mthreads -mno-align-stringops -minline-all-stringops @gol +-mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol +-m96bit-long-double -mregparm=@var{num} -msseregparm @gol +-mstackrealign @gol +-momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol +-mcmodel=@var{code-model} @gol +@c APPLE LOCAL begin 5946347 ms_struct support +-m32 -m64 -mlarge-data-threshold=@var{num} @gol +-mms-bitfields -mno-ms-bitfields} +@c APPLE LOCAL end 5946347 ms_struct support + +@c APPLE LOCAL prune man page +@ignore +@emph{IA-64 Options} +@gccoptlist{-mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol +-mvolatile-asm-stop -mregister-names -mno-sdata @gol +-mconstant-gp -mauto-pic -minline-float-divide-min-latency @gol +-minline-float-divide-max-throughput @gol +-minline-int-divide-min-latency @gol +-minline-int-divide-max-throughput @gol +-minline-sqrt-min-latency -minline-sqrt-max-throughput @gol +-mno-dwarf2-asm -mearly-stop-bits @gol +-mfixed-range=@var{register-range} -mtls-size=@var{tls-size} @gol +-mtune=@var{cpu-type} -mt -pthread -milp32 -mlp64 @gol +-mno-sched-br-data-spec -msched-ar-data-spec -mno-sched-control-spec @gol +-msched-br-in-data-spec -msched-ar-in-data-spec -msched-in-control-spec @gol +-msched-ldc -mno-sched-control-ldc -mno-sched-spec-verbose @gol +-mno-sched-prefer-non-data-spec-insns @gol +-mno-sched-prefer-non-control-spec-insns @gol +-mno-sched-count-spec-in-critical-path} + +@emph{M32R/D Options} +@gccoptlist{-m32r2 -m32rx -m32r @gol +-mdebug @gol +-malign-loops -mno-align-loops @gol +-missue-rate=@var{number} @gol +-mbranch-cost=@var{number} @gol +-mmodel=@var{code-size-model-type} @gol +-msdata=@var{sdata-type} @gol +-mno-flush-func -mflush-func=@var{name} @gol +-mno-flush-trap -mflush-trap=@var{number} @gol +-G @var{num}} + +@emph{M32C Options} +@gccoptlist{-mcpu=@var{cpu} -msim -memregs=@var{number}} + +@emph{M680x0 Options} +@gccoptlist{-m68000 -m68020 -m68020-40 -m68020-60 -m68030 -m68040 @gol +-m68060 -mcpu32 -m5200 -mcfv4e -m68881 -mbitfield @gol +-mc68000 -mc68020 @gol +-mnobitfield -mrtd -mshort -msoft-float -mpcrel @gol +-malign-int -mstrict-align -msep-data -mno-sep-data @gol +-mshared-library-id=n -mid-shared-library -mno-id-shared-library} + +@emph{M68hc1x Options} +@gccoptlist{-m6811 -m6812 -m68hc11 -m68hc12 -m68hcs12 @gol +-mauto-incdec -minmax -mlong-calls -mshort @gol +-msoft-reg-count=@var{count}} + +@emph{MCore Options} +@gccoptlist{-mhardlit -mno-hardlit -mdiv -mno-div -mrelax-immediates @gol +-mno-relax-immediates -mwide-bitfields -mno-wide-bitfields @gol +-m4byte-functions -mno-4byte-functions -mcallgraph-data @gol +-mno-callgraph-data -mslow-bytes -mno-slow-bytes -mno-lsim @gol +-mlittle-endian -mbig-endian -m210 -m340 -mstack-increment} + +@emph{MIPS Options} +@gccoptlist{-EL -EB -march=@var{arch} -mtune=@var{arch} @gol +-mips1 -mips2 -mips3 -mips4 -mips32 -mips32r2 -mips64 @gol +-mips16 -mno-mips16 -mabi=@var{abi} -mabicalls -mno-abicalls @gol +-mshared -mno-shared -mxgot -mno-xgot -mgp32 -mgp64 @gol +-mfp32 -mfp64 -mhard-float -msoft-float @gol +-msingle-float -mdouble-float -mdsp -mpaired-single -mips3d @gol +-mlong64 -mlong32 -msym32 -mno-sym32 @gol +-G@var{num} -membedded-data -mno-embedded-data @gol +-muninit-const-in-rodata -mno-uninit-const-in-rodata @gol +-msplit-addresses -mno-split-addresses @gol +-mexplicit-relocs -mno-explicit-relocs @gol +-mcheck-zero-division -mno-check-zero-division @gol +-mdivide-traps -mdivide-breaks @gol +-mmemcpy -mno-memcpy -mlong-calls -mno-long-calls @gol +-mmad -mno-mad -mfused-madd -mno-fused-madd -nocpp @gol +-mfix-r4000 -mno-fix-r4000 -mfix-r4400 -mno-fix-r4400 @gol +-mfix-vr4120 -mno-fix-vr4120 -mfix-vr4130 @gol +-mfix-sb1 -mno-fix-sb1 @gol +-mflush-func=@var{func} -mno-flush-func @gol +-mbranch-likely -mno-branch-likely @gol +-mfp-exceptions -mno-fp-exceptions @gol +-mvr4130-align -mno-vr4130-align} + +@emph{MMIX Options} +@gccoptlist{-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol +-mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol +-melf -mbranch-predict -mno-branch-predict -mbase-addresses @gol +-mno-base-addresses -msingle-exit -mno-single-exit} + +@emph{MN10300 Options} +@gccoptlist{-mmult-bug -mno-mult-bug @gol +-mam33 -mno-am33 @gol +-mam33-2 -mno-am33-2 @gol +-mreturn-pointer-on-d0 @gol +-mno-crt0 -mrelax} + +@emph{MT Options} +@gccoptlist{-mno-crt0 -mbacc -msim @gol +-march=@var{cpu-type} } + +@emph{PDP-11 Options} +@gccoptlist{-mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 @gol +-mbcopy -mbcopy-builtin -mint32 -mno-int16 @gol +-mint16 -mno-int32 -mfloat32 -mno-float64 @gol +-mfloat64 -mno-float32 -mabshi -mno-abshi @gol +-mbranch-expensive -mbranch-cheap @gol +-msplit -mno-split -munix-asm -mdec-asm} +@c APPLE LOCAL prune man page +@end ignore + +@emph{PowerPC Options} +See RS/6000 and PowerPC Options. + +@emph{RS/6000 and PowerPC Options} +@gccoptlist{-mcpu=@var{cpu-type} @gol +-mtune=@var{cpu-type} @gol +-mpower -mno-power -mpower2 -mno-power2 @gol +-mpowerpc -mpowerpc64 -mno-powerpc @gol +-maltivec -mno-altivec @gol +@c APPLE LOCAL AltiVec +-mpim-altivec -mno-pim-altivec @gol +-mpowerpc-gpopt -mno-powerpc-gpopt @gol +-mpowerpc-gfxopt -mno-powerpc-gfxopt @gol +-mmfcrf -mno-mfcrf -mpopcntb -mno-popcntb -mfprnd -mno-fprnd @gol +-mnew-mnemonics -mold-mnemonics @gol +-mfull-toc -mminimal-toc -mno-fp-in-toc -mno-sum-in-toc @gol +-m64 -m32 -mxl-compat -mno-xl-compat -mpe @gol +-malign-power -malign-natural @gol +-msoft-float -mhard-float -mmultiple -mno-multiple @gol +-mstring -mno-string -mupdate -mno-update @gol +-mfused-madd -mno-fused-madd -mbit-align -mno-bit-align @gol +-mstrict-align -mno-strict-align -mrelocatable @gol +-mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol +-mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol +-mdynamic-no-pic -maltivec -mswdiv @gol +-mprioritize-restricted-insns=@var{priority} @gol +-msched-costly-dep=@var{dependence_type} @gol +-minsert-sched-nops=@var{scheme} @gol +-mcall-sysv -mcall-netbsd @gol +-maix-struct-return -msvr4-struct-return @gol +-mabi=@var{abi-type} -msecure-plt -mbss-plt @gol +-misel -mno-isel @gol +-misel=yes -misel=no @gol +-mspe -mno-spe @gol +-mspe=yes -mspe=no @gol +-mvrsave -mno-vrsave @gol +-mmulhw -mno-mulhw @gol +-mdlmzb -mno-dlmzb @gol +-mfloat-gprs=yes -mfloat-gprs=no -mfloat-gprs=single -mfloat-gprs=double @gol +-mprototype -mno-prototype @gol +-msim -mmvme -mads -myellowknife -memb -msdata @gol +@c APPLE LOCAL begin 5946347 ms_struct support +-msdata=@var{opt} -mvxworks -mwindiss -G @var{num} -pthread @gol +-mms-bitfields -mno-ms-bitfields} +@c APPLE LOCAL end 5946347 ms_struct support + +@c APPLE LOCAL prune man page +@ignore +@emph{S/390 and zSeries Options} +@gccoptlist{-mtune=@var{cpu-type} -march=@var{cpu-type} @gol +-mhard-float -msoft-float -mlong-double-64 -mlong-double-128 @gol +-mbackchain -mno-backchain -mpacked-stack -mno-packed-stack @gol +-msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol +-m64 -m31 -mdebug -mno-debug -mesa -mzarch @gol +-mtpf-trace -mno-tpf-trace -mfused-madd -mno-fused-madd @gol +-mwarn-framesize -mwarn-dynamicstack -mstack-size -mstack-guard} + +@emph{Score Options} +@gccoptlist{-meb -mel @gol +-mnhwloop @gol +-muls @gol +-mmac @gol +-mscore5 -mscore5u -mscore7 -mscore7d} + +@emph{SH Options} +@gccoptlist{-m1 -m2 -m2e -m3 -m3e @gol +-m4-nofpu -m4-single-only -m4-single -m4 @gol +-m4a-nofpu -m4a-single-only -m4a-single -m4a -m4al @gol +-m5-64media -m5-64media-nofpu @gol +-m5-32media -m5-32media-nofpu @gol +-m5-compact -m5-compact-nofpu @gol +-mb -ml -mdalign -mrelax @gol +-mbigtable -mfmovd -mhitachi -mrenesas -mno-renesas -mnomacsave @gol +-mieee -misize -mpadstruct -mspace @gol +-mprefergot -musermode -multcost=@var{number} -mdiv=@var{strategy} @gol +-mdivsi3_libfunc=@var{name} @gol +-madjust-unroll -mindexed-addressing -mgettrcost=@var{number} -mpt-fixed @gol + -minvalid-symbols} + +@emph{SPARC Options} +@gccoptlist{-mcpu=@var{cpu-type} @gol +-mtune=@var{cpu-type} @gol +-mcmodel=@var{code-model} @gol +-m32 -m64 -mapp-regs -mno-app-regs @gol +-mfaster-structs -mno-faster-structs @gol +-mfpu -mno-fpu -mhard-float -msoft-float @gol +-mhard-quad-float -msoft-quad-float @gol +-mimpure-text -mno-impure-text -mlittle-endian @gol +-mstack-bias -mno-stack-bias @gol +-munaligned-doubles -mno-unaligned-doubles @gol +-mv8plus -mno-v8plus -mvis -mno-vis +-threads -pthreads -pthread} + +@emph{System V Options} +@gccoptlist{-Qy -Qn -YP,@var{paths} -Ym,@var{dir}} + +@emph{TMS320C3x/C4x Options} +@gccoptlist{-mcpu=@var{cpu} -mbig -msmall -mregparm -mmemparm @gol +-mfast-fix -mmpyi -mbk -mti -mdp-isr-reload @gol +-mrpts=@var{count} -mrptb -mdb -mloop-unsigned @gol +-mparallel-insns -mparallel-mpy -mpreserve-float} + +@emph{V850 Options} +@gccoptlist{-mlong-calls -mno-long-calls -mep -mno-ep @gol +-mprolog-function -mno-prolog-function -mspace @gol +-mtda=@var{n} -msda=@var{n} -mzda=@var{n} @gol +-mapp-regs -mno-app-regs @gol +-mdisable-callt -mno-disable-callt @gol +-mv850e1 @gol +-mv850e @gol +-mv850 -mbig-switch} + +@emph{VAX Options} +@gccoptlist{-mg -mgnu -munix} + +@emph{x86-64 Options} +See i386 and x86-64 Options. + +@emph{Xstormy16 Options} +@gccoptlist{-msim} + +@emph{Xtensa Options} +@gccoptlist{-mconst16 -mno-const16 @gol +-mfused-madd -mno-fused-madd @gol +-mtext-section-literals -mno-text-section-literals @gol +-mtarget-align -mno-target-align @gol +-mlongcalls -mno-longcalls} + +@emph{zSeries Options} +See S/390 and zSeries Options. +@c APPLE LOCAL prune man page +@end ignore + +@item Code Generation Options +@xref{Code Gen Options,,Options for Code Generation Conventions}. +@gccoptlist{-fcall-saved-@var{reg} -fcall-used-@var{reg} @gol +-ffixed-@var{reg} -fexceptions @gol +-fnon-call-exceptions -funwind-tables @gol +-fasynchronous-unwind-tables @gol +-finhibit-size-directive -finstrument-functions @gol +-fno-common -fno-ident @gol +-fpcc-struct-return -fpic -fPIC -fpie -fPIE @gol +-fno-jump-tables @gol +-freg-struct-return -fshort-enums @gol +-fshort-double -fshort-wchar @gol +-fverbose-asm -fpack-struct[=@var{n}] -fstack-check @gol +-fstack-limit-register=@var{reg} -fstack-limit-symbol=@var{sym} @gol +-fargument-alias -fargument-noalias @gol +-fargument-noalias-global -fargument-noalias-anything +-fleading-underscore -ftls-model=@var{model} @gol +@c APPLE LOCAL begin prune man page 5547358 +@c -ftrapv +-fwrapv -fbounds-check @gol +@c APPLE LOCAL end prune man page +-fvisibility} +@end table + +@menu +* Overall Options:: Controlling the kind of output: + an executable, object files, assembler files, + or preprocessed source. +* C Dialect Options:: Controlling the variant of C language compiled. +* C++ Dialect Options:: Variations on C++. +* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C + and Objective-C++. +* Language Independent Options:: Controlling how diagnostics should be + formatted. +* Warning Options:: How picky should the compiler be? +* Debugging Options:: Symbol tables, measurements, and debugging dumps. +* Optimize Options:: How much optimization? +* Preprocessor Options:: Controlling header files and macro definitions. + Also, getting dependency information for Make. +* Assembler Options:: Passing options to the assembler. +* Link Options:: Specifying libraries and so on. +* Directory Options:: Where to find header files and libraries. + Where to find the compiler executable files. +* Spec Files:: How to pass switches to sub-processes. +* Target Options:: Running a cross-compiler, or an old version of GCC. +@end menu + +@node Overall Options +@section Options Controlling the Kind of Output + +Compilation can involve up to four stages: preprocessing, compilation +proper, assembly and linking, always in that order. GCC is capable of +preprocessing and compiling several files either into several +assembler input files, or into one assembler input file; then each +assembler input file produces an object file, and linking combines all +the object files (those newly compiled, and those specified as input) +into an executable file. + +@cindex file name suffix +For any given input file, the file name suffix determines what kind of +compilation is done: + +@table @gcctabopt +@item @var{file}.c +C source code which must be preprocessed. + +@item @var{file}.i +C source code which should not be preprocessed. + +@item @var{file}.ii +C++ source code which should not be preprocessed. + +@item @var{file}.m +Objective-C source code. Note that you must link with the @file{libobjc} +library to make an Objective-C program work. + +@item @var{file}.mi +Objective-C source code which should not be preprocessed. + +@item @var{file}.mm +@itemx @var{file}.M +Objective-C++ source code. Note that you must link with the @file{libobjc} +library to make an Objective-C++ program work. Note that @samp{.M} refers +to a literal capital M@. + +@item @var{file}.mii +Objective-C++ source code which should not be preprocessed. + +@item @var{file}.h +C, C++, Objective-C or Objective-C++ header file to be turned into a +precompiled header. + +@item @var{file}.cc +@itemx @var{file}.cp +@itemx @var{file}.cxx +@itemx @var{file}.cpp +@itemx @var{file}.CPP +@itemx @var{file}.c++ +@itemx @var{file}.C +C++ source code which must be preprocessed. Note that in @samp{.cxx}, +the last two letters must both be literally @samp{x}. Likewise, +@samp{.C} refers to a literal capital C@. + +@c APPLE LOCAL begin Objective-C++ +@c Delete duplicate @var{file}.mm, @var{file}.M, @var{file}.mii. +@c APPLE LOCAL end Objective-C++ + +@item @var{file}.hh +@itemx @var{file}.H +C++ header file to be turned into a precompiled header. + +@item @var{file}.f +@itemx @var{file}.for +@itemx @var{file}.FOR +Fixed form Fortran source code which should not be preprocessed. + +@item @var{file}.F +@itemx @var{file}.fpp +@itemx @var{file}.FPP +Fixed form Fortran source code which must be preprocessed (with the traditional +preprocessor). + +@item @var{file}.f90 +@itemx @var{file}.f95 +Free form Fortran source code which should not be preprocessed. + +@item @var{file}.F90 +@itemx @var{file}.F95 +Free form Fortran source code which must be preprocessed (with the +traditional preprocessor). + +@c FIXME: Descriptions of Java file types. +@c @var{file}.java +@c @var{file}.class +@c @var{file}.zip +@c @var{file}.jar + +@item @var{file}.ads +Ada source code file which contains a library unit declaration (a +declaration of a package, subprogram, or generic, or a generic +instantiation), or a library unit renaming declaration (a package, +generic, or subprogram renaming declaration). Such files are also +called @dfn{specs}. + +@itemx @var{file}.adb +Ada source code file containing a library unit body (a subprogram or +package body). Such files are also called @dfn{bodies}. + +@c GCC also knows about some suffixes for languages not yet included: +@c Pascal: +@c @var{file}.p +@c @var{file}.pas +@c Ratfor: +@c @var{file}.r + +@item @var{file}.s +@c APPLE LOCAL begin preprocess .s files +Assembler code. Apple's version of GCC runs the preprocessor +on these files as well as those ending in @samp{.S}. +@c APPLE LOCAL end preprocess .s files + +@item @var{file}.S +Assembler code which must be preprocessed. + +@item @var{other} +An object file to be fed straight into linking. +Any file name with no recognized suffix is treated this way. +@end table + +@opindex x +You can specify the input language explicitly with the @option{-x} option: + +@table @gcctabopt +@item -x @var{language} +Specify explicitly the @var{language} for the following input files +(rather than letting the compiler choose a default based on the file +name suffix). This option applies to all following input files until +the next @option{-x} option. Possible values for @var{language} are: +@smallexample +c c-header c-cpp-output +c++ c++-header c++-cpp-output +objective-c objective-c-header objective-c-cpp-output +objective-c++ objective-c++-header objective-c++-cpp-output +assembler assembler-with-cpp +ada +f95 f95-cpp-input +java +treelang +@end smallexample + +@item -x none +Turn off any specification of a language, so that subsequent files are +handled according to their file name suffixes (as they are if @option{-x} +has not been used at all). + +@c APPLE LOCAL begin -ObjC 2001-08-03 --sts ** +@item -ObjC +@itemx -ObjC++ +@opindex ObjC +@opindex ObjC++ +These are similar in effect to @option{-x objective-c} and @option{-x +objective-c++}, but affect only the choice of compiler for files already +identified as source files. (APPLE ONLY) +@c APPLE LOCAL end -ObjC 2001-08-03 --sts ** + +@c APPLE LOCAL begin fat builds +@item -arch @var{arch} +@opindex arch +Compile for the specified target architecture @var{arch}. The +allowable values are @samp{i386}, @samp{x86_64}, @samp{ppc} and +@samp{ppc64}. Multiple options work, and direct the compiler to +produce ``universal'' binaries including object code for each +architecture specified with @option{-arch}. This option only works if +assembler and libraries are available for each architecture specified. +(APPLE ONLY) + +@item -Xarch_@var{arch} @var{option} +@opindex Xarch +Apply @var{option} to the command line for architecture @var{arch}. +This is useful for specifying an option that should only apply to +one architecture when building a ``universal'' binary. (APPLE ONLY) +@c APPLE LOCAL end fat builds + +@c APPLE LOCAL begin ss2 +@item -fsave-repository=@var{file} +@opindex fsave-repository +Save debug info in separate object file. +This is available only while building PCH in -gfull mode. +@c APPLE LOCAL end ss2 + +@item -pass-exit-codes +@opindex pass-exit-codes +Normally the @command{gcc} program will exit with the code of 1 if any +phase of the compiler returns a non-success return code. If you specify +@option{-pass-exit-codes}, the @command{gcc} program will instead return with +numerically highest error produced by any phase that returned an error +indication. The C, C++, and Fortran frontends return 4, if an internal +compiler error is encountered. +@end table + +If you only want some of the stages of compilation, you can use +@option{-x} (or filename suffixes) to tell @command{gcc} where to start, and +one of the options @option{-c}, @option{-S}, or @option{-E} to say where +@command{gcc} is to stop. Note that some combinations (for example, +@samp{-x cpp-output -E}) instruct @command{gcc} to do nothing at all. + +@table @gcctabopt +@item -c +@opindex c +Compile or assemble the source files, but do not link. The linking +stage simply is not done. The ultimate output is in the form of an +object file for each source file. + +By default, the object file name for a source file is made by replacing +the suffix @samp{.c}, @samp{.i}, @samp{.s}, etc., with @samp{.o}. + +Unrecognized input files, not requiring compilation or assembly, are +ignored. + +@item -S +@opindex S +Stop after the stage of compilation proper; do not assemble. The output +is in the form of an assembler code file for each non-assembler input +file specified. + +By default, the assembler file name for a source file is made by +replacing the suffix @samp{.c}, @samp{.i}, etc., with @samp{.s}. + +Input files that don't require compilation are ignored. + +@item -E +@opindex E +Stop after the preprocessing stage; do not run the compiler proper. The +output is in the form of preprocessed source code, which is sent to the +standard output. + +Input files which don't require preprocessing are ignored. + +@cindex output file option +@item -o @var{file} +@opindex o +Place output in file @var{file}. This applies regardless to whatever +sort of output is being produced, whether it be an executable file, +an object file, an assembler file or preprocessed C code. + +If @option{-o} is not specified, the default is to put an executable +file in @file{a.out}, the object file for +@file{@var{source}.@var{suffix}} in @file{@var{source}.o}, its +assembler file in @file{@var{source}.s}, a precompiled header file in +@file{@var{source}.@var{suffix}.gch}, and all preprocessed C source on +standard output. + +@item -v +@opindex v +Print (on standard error output) the commands executed to run the stages +of compilation. Also print the version number of the compiler driver +program and of the preprocessor and the compiler proper. + +@item -### +@opindex ### +Like @option{-v} except the commands are not executed and all command +arguments are quoted. This is useful for shell scripts to capture the +driver-generated command lines. + +@item -pipe +@opindex pipe +Use pipes rather than temporary files for communication between the +various stages of compilation. This fails to work on some systems where +the assembler is unable to read from a pipe; but the GNU assembler has +no trouble. + +@item -combine +@opindex combine +If you are compiling multiple source files, this option tells the driver +to pass all the source files to the compiler at once (for those +languages for which the compiler can handle this). This will allow +intermodule analysis (IMA) to be performed by the compiler. Currently the only +language for which this is supported is C@. If you pass source files for +multiple languages to the driver, using this option, the driver will invoke +the compiler(s) that support IMA once each, passing each compiler all the +source files appropriate for it. For those languages that do not support +IMA this option will be ignored, and the compiler will be invoked once for +each source file in that language. If you use this option in conjunction +with @option{-save-temps}, the compiler will generate multiple +pre-processed files +(one for each source file), but only one (combined) @file{.o} or +@file{.s} file. + +@item --help +@opindex help +Print (on the standard output) a description of the command line options +understood by @command{gcc}. If the @option{-v} option is also specified +then @option{--help} will also be passed on to the various processes +invoked by @command{gcc}, so that they can display the command line options +they accept. If the @option{-Wextra} option is also specified then command +line options which have no documentation associated with them will also +be displayed. + +@item --target-help +@opindex target-help +Print (on the standard output) a description of target specific command +line options for each tool. + +@item --version +@opindex version +Display the version number and copyrights of the invoked GCC@. + +@include @value{srcdir}/../libiberty/at-file.texi +@end table + +@node Invoking G++ +@section Compiling C++ Programs + +@cindex suffixes for C++ source +@cindex C++ source file suffixes +C++ source files conventionally use one of the suffixes @samp{.C}, +@samp{.cc}, @samp{.cpp}, @samp{.CPP}, @samp{.c++}, @samp{.cp}, or +@samp{.cxx}; C++ header files often use @samp{.hh} or @samp{.H}; and +preprocessed C++ files use the suffix @samp{.ii}. GCC recognizes +files with these names and compiles them as C++ programs even if you +call the compiler the same way as for compiling C programs (usually +with the name @command{gcc}). + +@findex g++ +@findex c++ +However, the use of @command{gcc} does not add the C++ library. +@command{g++} is a program that calls GCC and treats @samp{.c}, +@samp{.h} and @samp{.i} files as C++ source files instead of C source +files unless @option{-x} is used, and automatically specifies linking +against the C++ library. This program is also useful when +precompiling a C header file with a @samp{.h} extension for use in C++ +compilations. On many systems, @command{g++} is also installed with +the name @command{c++}. + +@cindex invoking @command{g++} +When you compile C++ programs, you may specify many of the same +command-line options that you use for compiling programs in any +language; or command-line options meaningful for C and related +languages; or options that are meaningful only for C++ programs. +@xref{C Dialect Options,,Options Controlling C Dialect}, for +explanations of options for languages related to C@. +@xref{C++ Dialect Options,,Options Controlling C++ Dialect}, for +explanations of options that are meaningful only for C++ programs. + +@node C Dialect Options +@section Options Controlling C Dialect +@cindex dialect options +@cindex language dialect options +@cindex options, dialect + +The following options control the dialect of C (or languages derived +from C, such as C++, Objective-C and Objective-C++) that the compiler +accepts: + +@table @gcctabopt +@cindex ANSI support +@cindex ISO support +@item -ansi +@opindex ansi +In C mode, support all ISO C90 programs. In C++ mode, +remove GNU extensions that conflict with ISO C++. + +This turns off certain features of GCC that are incompatible with ISO +C90 (when compiling C code), or of standard C++ (when compiling C++ code), +such as the @code{asm} and @code{typeof} keywords, and +predefined macros such as @code{unix} and @code{vax} that identify the +type of system you are using. It also enables the undesirable and +rarely used ISO trigraph feature. For the C compiler, +it disables recognition of C++ style @samp{//} comments as well as +the @code{inline} keyword. + +The alternate keywords @code{__asm__}, @code{__extension__}, +@code{__inline__} and @code{__typeof__} continue to work despite +@option{-ansi}. You would not want to use them in an ISO C program, of +course, but it is useful to put them in header files that might be included +in compilations done with @option{-ansi}. Alternate predefined macros +such as @code{__unix__} and @code{__vax__} are also available, with or +without @option{-ansi}. + +The @option{-ansi} option does not cause non-ISO programs to be +rejected gratuitously. For that, @option{-pedantic} is required in +addition to @option{-ansi}. @xref{Warning Options}. + +The macro @code{__STRICT_ANSI__} is predefined when the @option{-ansi} +option is used. Some header files may notice this macro and refrain +from declaring certain functions or defining certain macros that the +ISO standard doesn't call for; this is to avoid interfering with any +programs that might use these names for other things. + +Functions which would normally be built in but do not have semantics +defined by ISO C (such as @code{alloca} and @code{ffs}) are not built-in +functions with @option{-ansi} is used. @xref{Other Builtins,,Other +built-in functions provided by GCC}, for details of the functions +affected. + +@item -std= +@opindex std +Determine the language standard. This option is currently only +supported when compiling C or C++. A value for this option must be +provided; possible values are + +@table @samp +@item c89 +@itemx iso9899:1990 +ISO C90 (same as @option{-ansi}). + +@item iso9899:199409 +ISO C90 as modified in amendment 1. + +@item c99 +@itemx c9x +@itemx iso9899:1999 +@itemx iso9899:199x +ISO C99. Note that this standard is not yet fully supported; see +@w{@uref{http://gcc.gnu.org/gcc-4.2/c99status.html}} for more information. The +names @samp{c9x} and @samp{iso9899:199x} are deprecated. + +@item gnu89 +Default, ISO C90 plus GNU extensions (including some C99 features). + +@item gnu99 +@itemx gnu9x +ISO C99 plus GNU extensions. When ISO C99 is fully implemented in GCC, +this will become the default. The name @samp{gnu9x} is deprecated. + +@item c++98 +The 1998 ISO C++ standard plus amendments. + +@item gnu++98 +The same as @option{-std=c++98} plus GNU extensions. This is the +default for C++ code. +@end table + +Even when this option is not specified, you can still use some of the +features of newer standards in so far as they do not conflict with +previous C standards. For example, you may use @code{__restrict__} even +when @option{-std=c99} is not specified. + +The @option{-std} options specifying some version of ISO C have the same +effects as @option{-ansi}, except that features that were not in ISO C90 +but are in the specified version (for example, @samp{//} comments and +the @code{inline} keyword in ISO C99) are not disabled. + +@xref{Standards,,Language Standards Supported by GCC}, for details of +these standard versions. + +@item -fgnu89-inline +@opindex fgnu89-inline +The option @option{-fgnu89-inline} tells GCC to use the traditional +GNU semantics for @code{inline} functions when in C99 mode. +@xref{Inline,,An Inline Function is As Fast As a Macro}. Using this +option is roughly equivalent to adding the @code{gnu_inline} function +attribute to all inline functions (@pxref{Function Attributes}). + +This option is accepted by GCC versions 4.1.3 and up. In GCC versions +/* APPLE LOCAL extern inline */ +prior to 4.3 (4.2 for Apple's gcc), C99 inline semantics are not supported, and thus this +option is effectively assumed to be present regardless of whether or not +it is specified; the only effect of specifying it explicitly is to +disable warnings about using inline functions in C99 mode. Likewise, +the option @option{-fno-gnu89-inline} is not supported in versions of +/* APPLE LOCAL extern inline */ +GCC before 4.3 (4.2 for Apple's gcc). It is supported only in C99 or gnu99 mode, not in +C89 or gnu89 mode. + +The preprocesor macros @code{__GNUC_GNU_INLINE__} and +@code{__GNUC_STDC_INLINE__} may be used to check which semantics are +in effect for @code{inline} functions. @xref{Common Predefined +Macros,,,cpp,The C Preprocessor}. + +@item -aux-info @var{filename} +@opindex aux-info +Output to the given filename prototyped declarations for all functions +declared and/or defined in a translation unit, including those in header +files. This option is silently ignored in any language other than C@. + +Besides declarations, the file indicates, in comments, the origin of +each declaration (source file and line), whether the declaration was +implicit, prototyped or unprototyped (@samp{I}, @samp{N} for new or +@samp{O} for old, respectively, in the first character after the line +number and the colon), and whether it came from a declaration or a +definition (@samp{C} or @samp{F}, respectively, in the following +character). In the case of function definitions, a K&R-style list of +arguments followed by their declarations is also provided, inside +comments, after the declaration. + +@c APPLE LOCAL begin AltiVec +@item -faltivec +This flag is provided for compatibility with Metrowerks CodeWarrior and MrC +compilers as well as previous Apple versions of GCC. It causes the +@option{-mpim-altivec} option to be turned on. +@c APPLE LOCAL end AltiVec + +@c APPLE LOCAL begin CW asm blocks +@item -fasm-blocks +Enable the use of blocks and entire functions of assembly code within +a C or C++ file. The syntax follows that used in CodeWarrior. This +option is not supported for ARM targets. (APPLE ONLY) +@c APPLE LOCAL end CW asm blocks + +@item -fno-asm +@opindex fno-asm +Do not recognize @code{asm}, @code{inline} or @code{typeof} as a +keyword, so that code can use these words as identifiers. You can use +the keywords @code{__asm__}, @code{__inline__} and @code{__typeof__} +instead. @option{-ansi} implies @option{-fno-asm}. + +In C++, this switch only affects the @code{typeof} keyword, since +@code{asm} and @code{inline} are standard keywords. You may want to +use the @option{-fno-gnu-keywords} flag instead, which has the same +effect. In C99 mode (@option{-std=c99} or @option{-std=gnu99}), this +switch only affects the @code{asm} and @code{typeof} keywords, since +@code{inline} is a standard keyword in ISO C99. + +@c APPLE LOCAL begin blocks 7205047 5811887 +@item -fno-blocks +@opindex fno-blocks +Disable the use of blocks. In @option{-std=c99} mode, blocks are +turned off by default. @option{-fblocks} can be used to re-enable the +feature, if off. Runtime support for blocks first appeared in Mac OS +X 10.6. When targeting 10.6 (see @option{-mmacosx-version-min}) and +later, the extension is on by default. +@c APPLE LOCAL end blocks 7205047 5811887 + +@item -fno-builtin +@itemx -fno-builtin-@var{function} +@opindex fno-builtin +@cindex built-in functions +Don't recognize built-in functions that do not begin with +@samp{__builtin_} as prefix. @xref{Other Builtins,,Other built-in +functions provided by GCC}, for details of the functions affected, +including those which are not built-in functions when @option{-ansi} or +@option{-std} options for strict ISO C conformance are used because they +do not have an ISO standard meaning. + +GCC normally generates special code to handle certain built-in functions +more efficiently; for instance, calls to @code{alloca} may become single +instructions that adjust the stack directly, and calls to @code{memcpy} +may become inline copy loops. The resulting code is often both smaller +and faster, but since the function calls no longer appear as such, you +cannot set a breakpoint on those calls, nor can you change the behavior +of the functions by linking with a different library. In addition, +when a function is recognized as a built-in function, GCC may use +information about that function to warn about problems with calls to +that function, or to generate more efficient code, even if the +resulting code still contains calls to that function. For example, +warnings are given with @option{-Wformat} for bad calls to +@code{printf}, when @code{printf} is built in, and @code{strlen} is +known not to modify global memory. + +With the @option{-fno-builtin-@var{function}} option +only the built-in function @var{function} is +disabled. @var{function} must not begin with @samp{__builtin_}. If a +function is named this is not built-in in this version of GCC, this +option is ignored. There is no corresponding +@option{-fbuiltin-@var{function}} option; if you wish to enable +built-in functions selectively when using @option{-fno-builtin} or +@option{-ffreestanding}, you may define macros such as: + +@smallexample +#define abs(n) __builtin_abs ((n)) +#define strcpy(d, s) __builtin_strcpy ((d), (s)) +@end smallexample + +@item -fhosted +@opindex fhosted +@cindex hosted environment + +Assert that compilation takes place in a hosted environment. This implies +@option{-fbuiltin}. A hosted environment is one in which the +entire standard library is available, and in which @code{main} has a return +type of @code{int}. Examples are nearly everything except a kernel. +This is equivalent to @option{-fno-freestanding}. + +@item -ffreestanding +@opindex ffreestanding +@cindex hosted environment + +Assert that compilation takes place in a freestanding environment. This +implies @option{-fno-builtin}. A freestanding environment +is one in which the standard library may not exist, and program startup may +not necessarily be at @code{main}. The most obvious example is an OS kernel. +This is equivalent to @option{-fno-hosted}. + +@xref{Standards,,Language Standards Supported by GCC}, for details of +freestanding and hosted environments. + +@item -fopenmp +@opindex fopenmp +@cindex openmp parallel +Enable handling of OpenMP directives @code{#pragma omp} in C/C++ and +@code{!$omp} in Fortran. When @option{-fopenmp} is specified, the +compiler generates parallel code according to the OpenMP Application +Program Interface v2.5 @w{@uref{http://www.openmp.org/}}. + +@item -fms-extensions +@opindex fms-extensions +Accept some non-standard constructs used in Microsoft header files. + +Some cases of unnamed fields in structures and unions are only +accepted with this option. @xref{Unnamed Fields,,Unnamed struct/union +fields within structs/unions}, for details. + +@item -trigraphs +@opindex trigraphs +Support ISO C trigraphs. The @option{-ansi} option (and @option{-std} +options for strict ISO C conformance) implies @option{-trigraphs}. + +@item -no-integrated-cpp +@opindex no-integrated-cpp +Performs a compilation in two passes: preprocessing and compiling. This +option allows a user supplied "cc1", "cc1plus", or "cc1obj" via the +@option{-B} option. The user supplied compilation step can then add in +an additional preprocessing step after normal preprocessing but before +compiling. The default is to use the integrated cpp (internal cpp) + +The semantics of this option will change if "cc1", "cc1plus", and +"cc1obj" are merged. + +@cindex traditional C language +@cindex C language, traditional +@item -traditional +@itemx -traditional-cpp +@opindex traditional-cpp +@opindex traditional +Formerly, these options caused GCC to attempt to emulate a pre-standard +C compiler. They are now only supported with the @option{-E} switch. +The preprocessor continues to support a pre-standard mode. See the GNU +CPP manual for details. + +@item -fcond-mismatch +@opindex fcond-mismatch +Allow conditional expressions with mismatched types in the second and +third arguments. The value of such an expression is void. This option +is not supported for C++. + +@c APPLE LOCAL begin nested functions 4357979 +@item -fno-nested-functions +@opindex fno-nested-functions +Disable nested functions. This option is not supported for C++ or +Objective-C++. On Darwin, nested functions are disabled by default. +@c APPLE LOCAL end nested functions 4357979 + +@c APPLE LOCAL begin pch distcc --mrs +@item -fpch-preprocess +@opindex fpch-preprocess +Enable PCH processing even when @option{-E} or @option{-save-temps} is used. +@c APPLE LOCAL end pch distcc --mrs + +@c APPLE LOCAL begin non lvalue assign +@item -fnon-lvalue-assign +@opindex fnon-lvalue-assign +C and C++ forbid the use of casts and conditional expressions as lvalues, e.g.: + +@smallexample +float *p, q, r; +((int *)p)++; +(cond ? q : r) = 3.0; +@end smallexample + +@noindent +As a transitional measure, the Apple version of GCC 4.0 allows casts and +conditional expressions to be used as lvalues in certain situations. This +is accomplished via the @option{-fnon-lvalue-assign} switch, which is on +by default. Whenever an lvalue cast or an lvalue conditional expression is +encountered, the compiler will issue a deprecation warning and then rewrite +the expression as follows: + +@smallexample +(type)expr ---becomes---> *(type *)&expr +cond ? expr1 : expr2 ---becomes---> *(cond ? &expr1 : &expr2) +@end smallexample + +To disallow lvalue casts and lvalue conditional expressions altogether, +specify @option{-fno-non-lvalue-assign}; lvalue casts and lvalue conditional +expressions will be disallowed in future versions of Apple's GCC. +@c APPLE LOCAL end non lvalue assign + +@c APPLE LOCAL begin 5612787 sse4 +@item -flax-vector-conversions +@opindex flax-vector-conversions +Allow implicit conversions between vectors with differing numbers of +elements and/or incompatible element types. This option should not be +used for new code. +@c APPLE LOCAL end 5612787 sse4 + +@item -funsigned-char +@opindex funsigned-char +Let the type @code{char} be unsigned, like @code{unsigned char}. + +Each kind of machine has a default for what @code{char} should +be. It is either like @code{unsigned char} by default or like +@code{signed char} by default. + +Ideally, a portable program should always use @code{signed char} or +@code{unsigned char} when it depends on the signedness of an object. +But many programs have been written to use plain @code{char} and +expect it to be signed, or expect it to be unsigned, depending on the +machines they were written for. This option, and its inverse, let you +make such a program work with the opposite default. + +The type @code{char} is always a distinct type from each of +@code{signed char} or @code{unsigned char}, even though its behavior +is always just like one of those two. + +@item -fsigned-char +@opindex fsigned-char +Let the type @code{char} be signed, like @code{signed char}. + +Note that this is equivalent to @option{-fno-unsigned-char}, which is +the negative form of @option{-funsigned-char}. Likewise, the option +@option{-fno-signed-char} is equivalent to @option{-funsigned-char}. + +@item -fsigned-bitfields +@itemx -funsigned-bitfields +@itemx -fno-signed-bitfields +@itemx -fno-unsigned-bitfields +@opindex fsigned-bitfields +@opindex funsigned-bitfields +@opindex fno-signed-bitfields +@opindex fno-unsigned-bitfields +These options control whether a bit-field is signed or unsigned, when the +declaration does not use either @code{signed} or @code{unsigned}. By +default, such a bit-field is signed, because this is consistent: the +basic integer types such as @code{int} are signed types. + +@c APPLE LOCAL begin constant cfstrings +@item -fconstant-cfstrings +@opindex fconstant-cfstrings +Enable the automatic creation of a CoreFoundation-type constant string +whenever a special builtin @code{__builtin__CFStringMakeConstantString} +is called on a literal string. (APPLE ONLY) +@c APPLE LOCAL end constant cfstrings + +@c APPLE LOCAL begin radar 3506309 +@item -Wnonportable-cfstrings +@opindex Wnonportable-cfstrings +Warn if constant CFString objects contain non-portable characters +(default behavior) +@c APPLE LOCAL end radar 3506309 + +@c APPLE LOCAL begin 5695218 +@item -fglobal-alloc-prefer-bytes +@item -fno-global-alloc-prefer-bytes +@opindex fglobal-alloc-prefer-bytes +For the x86_32 architecture, prefer byte or short values to word +values during global register allocation. Some of the registers on +this target can't be used with values smaller than a 32-bit word; +allocating these values earlier increases the chance they will get a +byte-capable (or short-capable) register. Ignored for other targets. +Defaults on with global register allocation (@code{-Os}, @code{-O2}, +or @code{-O3}). (APPLE ONLY) +@c APPLE LOCAL end 5695218 +@c APPLE LOCAL begin fwritable strings. +@item -fwritable-strings +@opindex fwritable-strings +Store string constants in the writable data segment and don't uniquize +them. This is for compatibility with old programs which assume they can +write into string constants. + +Writing into string constants is a very bad idea; ``constants'' should +be constant. + +This option is deprecated. +@c APPLE LOCAL end fwritable strings. +@end table + +@node C++ Dialect Options +@section Options Controlling C++ Dialect + +@cindex compiler options, C++ +@cindex C++ options, command line +@cindex options, C++ +This section describes the command-line options that are only meaningful +for C++ programs; but you can also use most of the GNU compiler options +regardless of what language your program is in. For example, you +might compile a file @code{firstClass.C} like this: + +@smallexample +g++ -g -frepo -O -c firstClass.C +@end smallexample + +@noindent +In this example, only @option{-frepo} is an option meant +only for C++ programs; you can use the other options with any +language supported by GCC@. + +Here is a list of options that are @emph{only} for compiling C++ programs: + +@table @gcctabopt + +@item -fabi-version=@var{n} +@opindex fabi-version +Use version @var{n} of the C++ ABI@. Version 2 is the version of the +C++ ABI that first appeared in G++ 3.4. Version 1 is the version of +the C++ ABI that first appeared in G++ 3.2. Version 0 will always be +the version that conforms most closely to the C++ ABI specification. +Therefore, the ABI obtained using version 0 will change as ABI bugs +are fixed. + +The default is version 2. + +@item -fno-access-control +@opindex fno-access-control +Turn off all access checking. This switch is mainly useful for working +around bugs in the access control code. + +@item -fcheck-new +@opindex fcheck-new +Check that the pointer returned by @code{operator new} is non-null +before attempting to modify the storage allocated. This check is +normally unnecessary because the C++ standard specifies that +@code{operator new} will only return @code{0} if it is declared +@samp{throw()}, in which case the compiler will always check the +return value even without this option. In all other cases, when +@code{operator new} has a non-empty exception specification, memory +exhaustion is signalled by throwing @code{std::bad_alloc}. See also +@samp{new (nothrow)}. + +@item -fconserve-space +@opindex fconserve-space +Put uninitialized or runtime-initialized global variables into the +common segment, as C does. This saves space in the executable at the +cost of not diagnosing duplicate definitions. If you compile with this +flag and your program mysteriously crashes after @code{main()} has +completed, you may have an object that is being destroyed twice because +two definitions were merged. + +This option is no longer useful on most targets, now that support has +been added for putting variables into BSS without making them common. + +@item -ffriend-injection +@opindex ffriend-injection +Inject friend functions into the enclosing namespace, so that they are +visible outside the scope of the class in which they are declared. +Friend functions were documented to work this way in the old Annotated +C++ Reference Manual, and versions of G++ before 4.1 always worked +that way. However, in ISO C++ a friend function which is not declared +in an enclosing scope can only be found using argument dependent +lookup. This option causes friends to be injected as they were in +earlier releases. + +This option is for compatibility, and may be removed in a future +release of G++. + +@item -fno-elide-constructors +@opindex fno-elide-constructors +The C++ standard allows an implementation to omit creating a temporary +which is only used to initialize another object of the same type. +Specifying this option disables that optimization, and forces G++ to +call the copy constructor in all cases. + +@item -fno-enforce-eh-specs +@opindex fno-enforce-eh-specs +Don't generate code to check for violation of exception specifications +at runtime. This option violates the C++ standard, but may be useful +for reducing code size in production builds, much like defining +@samp{NDEBUG}. This does not give user code permission to throw +exceptions in violation of the exception specifications; the compiler +will still optimize based on the specifications, so throwing an +unexpected exception will result in undefined behavior. + +@item -ffor-scope +@itemx -fno-for-scope +@opindex ffor-scope +@opindex fno-for-scope +If @option{-ffor-scope} is specified, the scope of variables declared in +a @i{for-init-statement} is limited to the @samp{for} loop itself, +as specified by the C++ standard. +If @option{-fno-for-scope} is specified, the scope of variables declared in +a @i{for-init-statement} extends to the end of the enclosing scope, +as was the case in old versions of G++, and other (traditional) +implementations of C++. + +The default if neither flag is given to follow the standard, +but to allow and give a warning for old-style code that would +otherwise be invalid, or have different behavior. + +@item -fno-gnu-keywords +@opindex fno-gnu-keywords +Do not recognize @code{typeof} as a keyword, so that code can use this +word as an identifier. You can use the keyword @code{__typeof__} instead. +@option{-ansi} implies @option{-fno-gnu-keywords}. + +@item -fno-implicit-templates +@opindex fno-implicit-templates +Never emit code for non-inline templates which are instantiated +implicitly (i.e.@: by use); only emit code for explicit instantiations. +@xref{Template Instantiation}, for more information. + +@item -fno-implicit-inline-templates +@opindex fno-implicit-inline-templates +Don't emit code for implicit instantiations of inline templates, either. +The default is to handle inlines differently so that compiles with and +without optimization will need the same set of explicit instantiations. + +@item -fno-implement-inlines +@opindex fno-implement-inlines +To save space, do not emit out-of-line copies of inline functions +controlled by @samp{#pragma implementation}. This will cause linker +errors if these functions are not inlined everywhere they are called. + +@item -fms-extensions +@opindex fms-extensions +Disable pedantic warnings about constructs used in MFC, such as implicit +int and getting a pointer to member function via non-standard syntax. + +@item -fno-nonansi-builtins +@opindex fno-nonansi-builtins +Disable built-in declarations of functions that are not mandated by +ANSI/ISO C@. These include @code{ffs}, @code{alloca}, @code{_exit}, +@code{index}, @code{bzero}, @code{conjf}, and other related functions. + +@item -fno-operator-names +@opindex fno-operator-names +Do not treat the operator name keywords @code{and}, @code{bitand}, +@code{bitor}, @code{compl}, @code{not}, @code{or} and @code{xor} as +synonyms as keywords. + +@item -fno-optional-diags +@opindex fno-optional-diags +Disable diagnostics that the standard says a compiler does not need to +issue. Currently, the only such diagnostic issued by G++ is the one for +a name having multiple meanings within a class. + +@item -fpermissive +@opindex fpermissive +Downgrade some diagnostics about nonconformant code from errors to +warnings. Thus, using @option{-fpermissive} will allow some +nonconforming code to compile. + +@item -frepo +@opindex frepo +Enable automatic template instantiation at link time. This option also +implies @option{-fno-implicit-templates}. @xref{Template +Instantiation}, for more information. + +@item -fno-rtti +@opindex fno-rtti +Disable generation of information about every class with virtual +functions for use by the C++ runtime type identification features +(@samp{dynamic_cast} and @samp{typeid}). If you don't use those parts +of the language, you can save some space by using this flag. Note that +exception handling uses the same information, but it will generate it as +needed. The @samp{dynamic_cast} operator can still be used for casts that +do not require runtime type information, i.e. casts to @code{void *} or to +unambiguous base classes. + +@item -fstats +@opindex fstats +Emit statistics about front-end processing at the end of the compilation. +This information is generally only useful to the G++ development team. + +@item -ftemplate-depth-@var{n} +@opindex ftemplate-depth +Set the maximum instantiation depth for template classes to @var{n}. +A limit on the template instantiation depth is needed to detect +endless recursions during template class instantiation. ANSI/ISO C++ +conforming programs must not rely on a maximum depth greater than 17. + +@item -fno-threadsafe-statics +@opindex fno-threadsafe-statics +Do not emit the extra code to use the routines specified in the C++ +ABI for thread-safe initialization of local statics. You can use this +option to reduce code size slightly in code that doesn't need to be +thread-safe. + +@item -fuse-cxa-atexit +@opindex fuse-cxa-atexit +Register destructors for objects with static storage duration with the +@code{__cxa_atexit} function rather than the @code{atexit} function. +This option is required for fully standards-compliant handling of static +destructors, but will only work if your C library supports +@code{__cxa_atexit}. + +@item -fno-use-cxa-get-exception-ptr +@opindex fno-use-cxa-get-exception-ptr +Don't use the @code{__cxa_get_exception_ptr} runtime routine. This +will cause @code{std::uncaught_exception} to be incorrect, but is necessary +if the runtime routine is not available. + +@item -fvisibility-inlines-hidden +@opindex fvisibility-inlines-hidden +This switch declares that the user does not attempt to compare +pointers to inline methods where the addresses of the two functions +were taken in different shared objects. + +The effect of this is that GCC may, effectively, mark inline methods with +@code{__attribute__ ((visibility ("hidden")))} so that they do not +appear in the export table of a DSO and do not require a PLT indirection +when used within the DSO@. Enabling this option can have a dramatic effect +on load and link times of a DSO as it massively reduces the size of the +dynamic export table when the library makes heavy use of templates. + +The behaviour of this switch is not quite the same as marking the +methods as hidden directly, because it does not affect static variables +local to the function or cause the compiler to deduce that +the function is defined in only one shared object. + +You may mark a method as having a visibility explicitly to negate the +effect of the switch for that method. For example, if you do want to +compare pointers to a particular inline method, you might mark it as +having default visibility. Marking the enclosing class with explicit +visibility will have no effect. + +Explicitly instantiated inline methods are unaffected by this option +as their linkage might otherwise cross a shared library boundary. +@xref{Template Instantiation}. + +@c APPLE LOCAL begin mainline 2007-06-28 ms tinfo compat 4230099 +@item -fvisibility-ms-compat +@opindex fvisibility-ms-compat +This flag attempts to use visibility settings to make GCC's C++ +linkage model compatible with that of Microsoft Visual Studio. + +The flag makes these changes to GCC's linkage model: + +1. It sets the default visibility to 'hidden', like +@option{-fvisibility=hidden}. +2. Types, but not their members, are not hidden by default. +3. The One Definition Rule is relaxed for types without explicit +visibility specifications which are defined in more than one different +shared object: those declarations are permitted if they would have +been permitted when this option was not used. + +This option is discouraged, rather, it is preferable for types to be +explicitly exported as desired on a per-class basis. Unfortunately +because Visual Studio can't compare two different hidden types as +unequal for the purposes of type_info and exception handling, users +are able to write code that relies upon this behavior. + +Among the consequences of these changes are that static data members +of the same type with the same name but defined in different shared +objects will be different, so changing one will not change the other; +and that pointers to function members defined in different shared +objects will not compare equal. When this flag is given, it is a +violation of the ODR to define types with the same name differently. +@c APPLE LOCAL end mainline 2007-06-28 ms tinfo compat 4230099 + +@item -fno-weak +@opindex fno-weak +Do not use weak symbol support, even if it is provided by the linker. +By default, G++ will use weak symbols if they are available. This +option exists only for testing, and should not be used by end-users; +it will result in inferior code and has no benefits. This option may +be removed in a future release of G++. + +@item -nostdinc++ +@opindex nostdinc++ +Do not search for header files in the standard directories specific to +C++, but do still search the other standard directories. (This option +is used when building the C++ library.) +@end table + +In addition, these optimization, warning, and code generation options +have meanings only for C++ programs: + +@table @gcctabopt +@item -fno-default-inline +@opindex fno-default-inline +Do not assume @samp{inline} for functions defined inside a class scope. +@xref{Optimize Options,,Options That Control Optimization}. Note that these +functions will have linkage like inline functions; they just won't be +inlined by default. + +@item -Wabi @r{(C++ only)} +@opindex Wabi +Warn when G++ generates code that is probably not compatible with the +vendor-neutral C++ ABI@. Although an effort has been made to warn about +all such cases, there are probably some cases that are not warned about, +even though G++ is generating incompatible code. There may also be +cases where warnings are emitted even though the code that is generated +will be compatible. + +You should rewrite your code to avoid these warnings if you are +concerned about the fact that code generated by G++ may not be binary +compatible with code generated by other compilers. + +The known incompatibilities at this point include: + +@itemize @bullet + +@item +Incorrect handling of tail-padding for bit-fields. G++ may attempt to +pack data into the same byte as a base class. For example: + +@smallexample +struct A @{ virtual void f(); int f1 : 1; @}; +struct B : public A @{ int f2 : 1; @}; +@end smallexample + +@noindent +In this case, G++ will place @code{B::f2} into the same byte +as@code{A::f1}; other compilers will not. You can avoid this problem +by explicitly padding @code{A} so that its size is a multiple of the +byte size on your platform; that will cause G++ and other compilers to +layout @code{B} identically. + +@item +Incorrect handling of tail-padding for virtual bases. G++ does not use +tail padding when laying out virtual bases. For example: + +@smallexample +struct A @{ virtual void f(); char c1; @}; +struct B @{ B(); char c2; @}; +struct C : public A, public virtual B @{@}; +@end smallexample + +@noindent +In this case, G++ will not place @code{B} into the tail-padding for +@code{A}; other compilers will. You can avoid this problem by +explicitly padding @code{A} so that its size is a multiple of its +alignment (ignoring virtual base classes); that will cause G++ and other +compilers to layout @code{C} identically. + +@item +Incorrect handling of bit-fields with declared widths greater than that +of their underlying types, when the bit-fields appear in a union. For +example: + +@smallexample +union U @{ int i : 4096; @}; +@end smallexample + +@noindent +Assuming that an @code{int} does not have 4096 bits, G++ will make the +union too small by the number of bits in an @code{int}. + +@item +Empty classes can be placed at incorrect offsets. For example: + +@smallexample +struct A @{@}; + +struct B @{ + A a; + virtual void f (); +@}; + +struct C : public B, public A @{@}; +@end smallexample + +@noindent +G++ will place the @code{A} base class of @code{C} at a nonzero offset; +it should be placed at offset zero. G++ mistakenly believes that the +@code{A} data member of @code{B} is already at offset zero. + +@item +Names of template functions whose types involve @code{typename} or +template template parameters can be mangled incorrectly. + +@smallexample +template <typename Q> +void f(typename Q::X) @{@} + +template <template <typename> class Q> +void f(typename Q<int>::X) @{@} +@end smallexample + +@noindent +Instantiations of these templates may be mangled incorrectly. + +@end itemize + +@item -Wctor-dtor-privacy @r{(C++ only)} +@opindex Wctor-dtor-privacy +Warn when a class seems unusable because all the constructors or +destructors in that class are private, and it has neither friends nor +public static member functions. + +@item -Wnon-virtual-dtor @r{(C++ only)} +@opindex Wnon-virtual-dtor +Warn when a class appears to be polymorphic, thereby requiring a virtual +destructor, yet it declares a non-virtual one. This warning is also +enabled if -Weffc++ is specified. + +@item -Wreorder @r{(C++ only)} +@opindex Wreorder +@cindex reordering, warning +@cindex warning for reordering of member initializers +Warn when the order of member initializers given in the code does not +match the order in which they must be executed. For instance: + +@smallexample +struct A @{ + int i; + int j; + A(): j (0), i (1) @{ @} +@}; +@end smallexample + +The compiler will rearrange the member initializers for @samp{i} +and @samp{j} to match the declaration order of the members, emitting +a warning to that effect. This warning is enabled by @option{-Wall}. +@end table + +The following @option{-W@dots{}} options are not affected by @option{-Wall}. + +@table @gcctabopt +@item -Weffc++ @r{(C++ only)} +@opindex Weffc++ +Warn about violations of the following style guidelines from Scott Meyers' +@cite{Effective C++} book: + +@itemize @bullet +@item +Item 11: Define a copy constructor and an assignment operator for classes +with dynamically allocated memory. + +@item +Item 12: Prefer initialization to assignment in constructors. + +@item +Item 14: Make destructors virtual in base classes. + +@item +Item 15: Have @code{operator=} return a reference to @code{*this}. + +@item +Item 23: Don't try to return a reference when you must return an object. + +@end itemize + +Also warn about violations of the following style guidelines from +Scott Meyers' @cite{More Effective C++} book: + +@itemize @bullet +@item +Item 6: Distinguish between prefix and postfix forms of increment and +decrement operators. + +@item +Item 7: Never overload @code{&&}, @code{||}, or @code{,}. + +@end itemize + +When selecting this option, be aware that the standard library +headers do not obey all of these guidelines; use @samp{grep -v} +to filter out those warnings. + +@item -Wno-deprecated @r{(C++ only)} +@opindex Wno-deprecated +Do not warn about usage of deprecated features. @xref{Deprecated Features}. + +@item -Wstrict-null-sentinel @r{(C++ only)} +@opindex Wstrict-null-sentinel +Warn also about the use of an uncasted @code{NULL} as sentinel. When +compiling only with GCC this is a valid sentinel, as @code{NULL} is defined +to @code{__null}. Although it is a null pointer constant not a null pointer, +it is guaranteed to of the same size as a pointer. But this use is +not portable across different compilers. + +@item -Wno-non-template-friend @r{(C++ only)} +@opindex Wno-non-template-friend +Disable warnings when non-templatized friend functions are declared +within a template. Since the advent of explicit template specification +support in G++, if the name of the friend is an unqualified-id (i.e., +@samp{friend foo(int)}), the C++ language specification demands that the +friend declare or define an ordinary, nontemplate function. (Section +14.5.3). Before G++ implemented explicit specification, unqualified-ids +could be interpreted as a particular specialization of a templatized +function. Because this non-conforming behavior is no longer the default +behavior for G++, @option{-Wnon-template-friend} allows the compiler to +check existing code for potential trouble spots and is on by default. +This new compiler behavior can be turned off with +@option{-Wno-non-template-friend} which keeps the conformant compiler code +but disables the helpful warning. + +@item -Wold-style-cast @r{(C++ only)} +@opindex Wold-style-cast +Warn if an old-style (C-style) cast to a non-void type is used within +a C++ program. The new-style casts (@samp{dynamic_cast}, +@samp{static_cast}, @samp{reinterpret_cast}, and @samp{const_cast}) are +less vulnerable to unintended effects and much easier to search for. + +@item -Woverloaded-virtual @r{(C++ only)} +@opindex Woverloaded-virtual +@cindex overloaded virtual fn, warning +@cindex warning for overloaded virtual fn +Warn when a function declaration hides virtual functions from a +base class. For example, in: + +@smallexample +struct A @{ + virtual void f(); +@}; + +struct B: public A @{ + void f(int); +@}; +@end smallexample + +the @code{A} class version of @code{f} is hidden in @code{B}, and code +like: + +@smallexample +B* b; +b->f(); +@end smallexample + +will fail to compile. + +@item -Wno-pmf-conversions @r{(C++ only)} +@opindex Wno-pmf-conversions +Disable the diagnostic for converting a bound pointer to member function +to a plain pointer. + +@item -Wsign-promo @r{(C++ only)} +@opindex Wsign-promo +Warn when overload resolution chooses a promotion from unsigned or +enumerated type to a signed type, over a conversion to an unsigned type of +the same size. Previous versions of G++ would try to preserve +unsignedness, but the standard mandates the current behavior. + +@smallexample +struct A @{ + operator int (); + A& operator = (int); +@}; + +main () +@{ + A a,b; + a = b; +@} +@end smallexample + +In this example, G++ will synthesize a default @samp{A& operator = +(const A&);}, while cfront will use the user-defined @samp{operator =}. +@end table + +@node Objective-C and Objective-C++ Dialect Options +@section Options Controlling Objective-C and Objective-C++ Dialects + +@cindex compiler options, Objective-C and Objective-C++ +@cindex Objective-C and Objective-C++ options, command line +@cindex options, Objective-C and Objective-C++ +(NOTE: This manual does not describe the Objective-C and Objective-C++ +languages themselves. See @xref{Standards,,Language Standards +Supported by GCC}, for references.) + +This section describes the command-line options that are only meaningful +for Objective-C and Objective-C++ programs, but you can also use most of +the language-independent GNU compiler options. +For example, you might compile a file @code{some_class.m} like this: + +@smallexample +gcc -g -fgnu-runtime -O -c some_class.m +@end smallexample + +@noindent +In this example, @option{-fgnu-runtime} is an option meant only for +Objective-C and Objective-C++ programs; you can use the other options with +any language supported by GCC@. + +Note that since Objective-C is an extension of the C language, Objective-C +compilations may also use options specific to the C front-end (e.g., +@option{-Wtraditional}). Similarly, Objective-C++ compilations may use +C++-specific options (e.g., @option{-Wabi}). + +Here is a list of options that are @emph{only} for compiling Objective-C +and Objective-C++ programs: + +@table @gcctabopt +@item -fconstant-string-class=@var{class-name} +@opindex fconstant-string-class +Use @var{class-name} as the name of the class to instantiate for each +literal string specified with the syntax @code{@@"@dots{}"}. The default +class name is @code{NXConstantString} if the GNU runtime is being used, and +@code{NSConstantString} if the NeXT runtime is being used (see below). The +@option{-fconstant-cfstrings} option, if also present, will override the +@option{-fconstant-string-class} setting and cause @code{@@"@dots{}"} literals +to be laid out as constant CoreFoundation strings. + +@item -fgnu-runtime +@opindex fgnu-runtime +Generate object code compatible with the standard GNU Objective-C +runtime. This is the default for most types of systems. + +@item -fnext-runtime +@opindex fnext-runtime +Generate output compatible with the NeXT runtime. This is the default +for NeXT-based systems, including Darwin and Mac OS X@. The macro +@code{__NEXT_RUNTIME__} is predefined if (and only if) this option is +used. + +@item -fno-nil-receivers +@opindex fno-nil-receivers +Assume that all Objective-C message dispatches (e.g., +@code{[receiver message:arg]}) in this translation unit ensure that the receiver +is not @code{nil}. This allows for more efficient entry points in the runtime +to be used. Currently, this option is only available in conjunction with +the NeXT runtime on Mac OS X 10.3 and later. + +@item -fobjc-call-cxx-cdtors +@opindex fobjc-call-cxx-cdtors +For each Objective-C class, check if any of its instance variables is a +C++ object with a non-trivial default constructor. If so, synthesize a +special @code{- (id) .cxx_construct} instance method that will run +non-trivial default constructors on any such instance variables, in order, +and then return @code{self}. Similarly, check if any instance variable +is a C++ object with a non-trivial destructor, and if so, synthesize a +special @code{- (void) .cxx_destruct} method that will run +all such default destructors, in reverse order. + +The @code{- (id) .cxx_construct} and/or @code{- (void) .cxx_destruct} methods +thusly generated will only operate on instance variables declared in the +current Objective-C class, and not those inherited from superclasses. It +is the responsibility of the Objective-C runtime to invoke all such methods +in an object's inheritance hierarchy. The @code{- (id) .cxx_construct} methods +will be invoked by the runtime immediately after a new object +instance is allocated; the @code{- (void) .cxx_destruct} methods will +be invoked immediately before the runtime deallocates an object instance. + +As of this writing, only the NeXT runtime on Mac OS X 10.4 and later has +support for invoking the @code{- (id) .cxx_construct} and +@code{- (void) .cxx_destruct} methods. + +@item -fobjc-direct-dispatch +@opindex fobjc-direct-dispatch +Allow fast jumps to the message dispatcher. On Darwin this is +accomplished via the comm page. + +@c APPLE LOCAL begin radar 4512786 +@item -fobjc-sjlj-exceptions +@opindex fobjc-sjlj-exceptions +Enable syntactic support for structured exception handling in Objective-C, +similar to what is offered by C++ and Java. This option is +unavailable in conjunction with the NeXT runtime on Mac OS X 10.2 and +earlier. +This option is on by default with the NeXT runtime. +@c APPLE LOCAL end radar 4512786 + +@smallexample + @@try @{ + @dots{} + @@throw expr; + @dots{} + @} + @@catch (AnObjCClass *exc) @{ + @dots{} + @@throw expr; + @dots{} + @@throw; + @dots{} + @} + @@catch (AnotherClass *exc) @{ + @dots{} + @} + @@catch (id allOthers) @{ + @dots{} + @} + @@finally @{ + @dots{} + @@throw expr; + @dots{} + @} +@end smallexample + +The @code{@@throw} statement may appear anywhere in an Objective-C or +Objective-C++ program; when used inside of a @code{@@catch} block, the +@code{@@throw} may appear without an argument (as shown above), in which case +the object caught by the @code{@@catch} will be rethrown. + +Note that only (pointers to) Objective-C objects may be thrown and +caught using this scheme. When an object is thrown, it will be caught +by the nearest @code{@@catch} clause capable of handling objects of that type, +analogously to how @code{catch} blocks work in C++ and Java. A +@code{@@catch(id @dots{})} clause (as shown above) may also be provided to catch +any and all Objective-C exceptions not caught by previous @code{@@catch} +clauses (if any). + +The @code{@@finally} clause, if present, will be executed upon exit from the +immediately preceding @code{@@try @dots{} @@catch} section. This will happen +regardless of whether any exceptions are thrown, caught or rethrown +inside the @code{@@try @dots{} @@catch} section, analogously to the behavior +of the @code{finally} clause in Java. + +There are several caveats to using the new exception mechanism: + +@itemize @bullet +@item +Although currently designed to be binary compatible with @code{NS_HANDLER}-style +idioms provided by the @code{NSException} class, the new +exceptions can only be used on Mac OS X 10.3 (Panther) and later +systems, due to additional functionality needed in the (NeXT) Objective-C +runtime. + +@item +As mentioned above, the new exceptions do not support handling +types other than Objective-C objects. Furthermore, when used from +Objective-C++, the Objective-C exception model does not interoperate with C++ +exceptions at this time. This means you cannot @code{@@throw} an exception +from Objective-C and @code{catch} it in C++, or vice versa +(i.e., @code{throw @dots{} @@catch}). +@end itemize + +@c APPLE LOCAL radar 4512786 +The @option{-fobjc-sjlj-exceptions} switch also enables the use of synchronization +blocks for thread-safe execution: + +@smallexample + @@synchronized (ObjCClass *guard) @{ + @dots{} + @} +@end smallexample + +Upon entering the @code{@@synchronized} block, a thread of execution shall +first check whether a lock has been placed on the corresponding @code{guard} +object by another thread. If it has, the current thread shall wait until +the other thread relinquishes its lock. Once @code{guard} becomes available, +the current thread will place its own lock on it, execute the code contained in +the @code{@@synchronized} block, and finally relinquish the lock (thereby +making @code{guard} available to other threads). + +Unlike Java, Objective-C does not allow for entire methods to be marked +@code{@@synchronized}. Note that throwing exceptions out of +@code{@@synchronized} blocks is allowed, and will cause the guarding object +to be unlocked properly. + +@item -fobjc-gc +@opindex fobjc-gc +Enable garbage collection (GC) in Objective-C and Objective-C++ programs. +@c APPLE LOCAL begin radar 5780114 - ObjC GC +The resulting binary requires additional runtime support which is present on +Mac OS X Version 10.5 (Leopard) and later. All Objective-C objects are presumed +to be garbage collected. To aid in this effort, compiler implements assignments +of Objective-C object pointers via runtime support functions. These functions work +correctly in non-GC environments as well, in case this code is used as part of a +library. Assignments of objects into instance variables of other objects are +intercepted, so are assignments to global object variables. In general, assignments +through pointers to objects are intercepted. Additionally, assignments of objects +as fields within structures are intercepted. + +In addition, other pointer variables may be marked with the __strong storage class +modifier to indicate to the compiler that these assignments need to use the assignment +runtime functions as well, allowing the memory referenced by these pointers to be +allocated from the collector. A __weak storage class modifier for pointers is also +introduced to indicate a zero-ing weak reference. This is permitted only for instance +variables of an object or globals. The compiler arranges for all reads as well as +writes to these variables to occur via runtime support functions. Under garbage +collection these variables are not consulted when determining what is not garbage +and they are set to nil (zero) if the memory they reference is deemed garbage and is +collected. + +@smallexample + __strong void *p; // assignments to 'p' will have runtime support calls + int *q; // assignments to 'q' ordinarly will not + @dots{} + (__strong int *)q = 0; // this assignment will call a runtime support function +@end smallexample + +Conversely, the @code{__weak} type qualifier may be used to call weak runtime +functions. + +@smallexample + __weak id q; // assignments to 'q' will have the '__weak' semantics + id p; // assignments to 'p' will have the "__strong' semantics + @dots{} + (__weak id)p = 0; // Fall back to '__weak' semantics in this assignment. +@end smallexample + +@item -fobjc-gc-only +@opindex fobjc-gc-only +Use this option to indicate that the Objective-C program supports garbage +collection (GC) only - that is, it does not contain retain/release logic. +This flag implies @option{-fobjc-gc} as well. With this flag, framework +is marked as not honoring retain/release. + +@c APPLE LOCAL end radar 5780114 - ObjC GC +@item -freplace-objc-classes +@opindex freplace-objc-classes +Emit a special marker instructing @command{ld(1)} not to statically link in +the resulting object file, and allow @command{dyld(1)} to load it in at +run time instead. This is used in conjunction with the Fix-and-Continue +debugging mode, where the object file in question may be recompiled and +dynamically reloaded in the course of program execution, without the need +to restart the program itself. Currently, Fix-and-Continue functionality +is only available in conjunction with the NeXT runtime on Mac OS X 10.3 +and later. + +@item -fzero-link +@opindex fzero-link +When compiling for the NeXT runtime, the compiler ordinarily replaces calls +to @code{objc_getClass("@dots{}")} (when the name of the class is known at +compile time) with static class references that get initialized at load time, +which improves run-time performance. Specifying the @option{-fzero-link} flag +suppresses this behavior and causes calls to @code{objc_getClass("@dots{}")} +to be retained. This is useful in Zero-Link debugging mode, since it allows +for individual class implementations to be modified during program execution. + +@item -gen-decls +@opindex gen-decls +Dump interface declarations for all classes seen in the source file to a +file named @file{@var{sourcename}.decl}. + +@item -Wassign-intercept +@opindex Wassign-intercept +Warn whenever an Objective-C assignment is being intercepted by the +garbage collector. + +@item -Wno-protocol +@opindex Wno-protocol +If a class is declared to implement a protocol, a warning is issued for +every method in the protocol that is not implemented by the class. The +default behavior is to issue a warning for every method not explicitly +implemented in the class, even if a method implementation is inherited +from the superclass. If you use the @option{-Wno-protocol} option, then +methods inherited from the superclass are considered to be implemented, +and no warning is issued for them. + +@item -Wselector +@opindex Wselector +Warn if multiple methods of different types for the same selector are +found during compilation. The check is performed on the list of methods +in the final stage of compilation. Additionally, a check is performed +for each selector appearing in a @code{@@selector(@dots{})} +expression, and a corresponding method for that selector has been found +during compilation. Because these checks scan the method table only at +the end of compilation, these warnings are not produced if the final +stage of compilation is not reached, for example because an error is +found during compilation, or because the @option{-fsyntax-only} option is +being used. + +@c APPLE LOCAL begin radar 5172645 +@item -Wproperty-assign-default +@opindex Wproperty-assign-default +Warn if no ``assign'', ``retain'', or ``copy'' attribute is specified on +a property of pointer to object type. Property is then assumed to be +``assign'' by default. +@c APPLE LOCAL end radar 5172645 + +@c APPLE LOCAL begin radar 5376125 +@item -Wdirect-ivar-access +@opindex Wdirect-ivar-access +Warn if ivar of pointer to object type is directly accessed in non-gc +mode, instead of using property syntax access. +@c APPLE LOCAL end radar 5376125 + +@item -Wstrict-selector-match +@opindex Wstrict-selector-match +Warn if multiple methods with differing argument and/or return types are +found for a given selector when attempting to send a message using this +selector to a receiver of type @code{id} or @code{Class}. When this flag +is off (which is the default behavior), the compiler will omit such warnings +if any differences found are confined to types which share the same size +and alignment. + +@item -Wundeclared-selector +@opindex Wundeclared-selector +Warn if a @code{@@selector(@dots{})} expression referring to an +undeclared selector is found. A selector is considered undeclared if no +method with that name has been declared before the +@code{@@selector(@dots{})} expression, either explicitly in an +@code{@@interface} or @code{@@protocol} declaration, or implicitly in +an @code{@@implementation} section. This option always performs its +checks as soon as a @code{@@selector(@dots{})} expression is found, +while @option{-Wselector} only performs its checks in the final stage of +compilation. This also enforces the coding style convention +that methods and selectors must be declared before being used. + +@item -print-objc-runtime-info +@opindex print-objc-runtime-info +Generate C header describing the largest structure that is passed by +value, if any. + +@end table + +@node Language Independent Options +@section Options to Control Diagnostic Messages Formatting +@cindex options to control diagnostics formatting +@cindex diagnostic messages +@cindex message formatting + +Traditionally, diagnostic messages have been formatted irrespective of +the output device's aspect (e.g.@: its width, @dots{}). The options described +below can be used to control the diagnostic messages formatting +algorithm, e.g.@: how many characters per line, how often source location +information should be reported. Right now, only the C++ front end can +honor these options. However it is expected, in the near future, that +the remaining front ends would be able to digest them correctly. + +@table @gcctabopt +@item -fmessage-length=@var{n} +@opindex fmessage-length +Try to format error messages so that they fit on lines of about @var{n} +characters. The default is 72 characters for @command{g++} and 0 for the rest of +the front ends supported by GCC@. If @var{n} is zero, then no +line-wrapping will be done; each error message will appear on a single +line. + +@opindex fdiagnostics-show-location +@item -fdiagnostics-show-location=once +Only meaningful in line-wrapping mode. Instructs the diagnostic messages +reporter to emit @emph{once} source location information; that is, in +case the message is too long to fit on a single physical line and has to +be wrapped, the source location won't be emitted (as prefix) again, +over and over, in subsequent continuation lines. This is the default +behavior. + +@item -fdiagnostics-show-location=every-line +Only meaningful in line-wrapping mode. Instructs the diagnostic +messages reporter to emit the same source location information (as +prefix) for physical lines that result from the process of breaking +a message which is too long to fit on a single line. + +@item -fdiagnostics-show-option +@opindex fdiagnostics-show-option +This option instructs the diagnostic machinery to add text to each +diagnostic emitted, which indicates which command line option directly +controls that diagnostic, when such an option is known to the +diagnostic machinery. + +@end table + +@node Warning Options +@section Options to Request or Suppress Warnings +@cindex options to control warnings +@cindex warning messages +@cindex messages, warning +@cindex suppressing warnings + +Warnings are diagnostic messages that report constructions which +are not inherently erroneous but which are risky or suggest there +may have been an error. + +You can request many specific warnings with options beginning @samp{-W}, +for example @option{-Wimplicit} to request warnings on implicit +declarations. Each of these specific warning options also has a +negative form beginning @samp{-Wno-} to turn off warnings; +for example, @option{-Wno-implicit}. This manual lists only one of the +two forms, whichever is not the default. + +The following options control the amount and kinds of warnings produced +by GCC; for further, language-specific options also refer to +@ref{C++ Dialect Options} and @ref{Objective-C and Objective-C++ Dialect +Options}. + +@table @gcctabopt +@cindex syntax checking +@item -fsyntax-only +@opindex fsyntax-only +Check the code for syntax errors, but don't do anything beyond that. + +@item -pedantic +@opindex pedantic +Issue all the warnings demanded by strict ISO C and ISO C++; +reject all programs that use forbidden extensions, and some other +programs that do not follow ISO C and ISO C++. For ISO C, follows the +version of the ISO C standard specified by any @option{-std} option used. + +Valid ISO C and ISO C++ programs should compile properly with or without +this option (though a rare few will require @option{-ansi} or a +@option{-std} option specifying the required version of ISO C)@. However, +without this option, certain GNU extensions and traditional C and C++ +features are supported as well. With this option, they are rejected. + +@option{-pedantic} does not cause warning messages for use of the +alternate keywords whose names begin and end with @samp{__}. Pedantic +warnings are also disabled in the expression that follows +@code{__extension__}. However, only system header files should use +these escape routes; application programs should avoid them. +@xref{Alternate Keywords}. + +Some users try to use @option{-pedantic} to check programs for strict ISO +C conformance. They soon find that it does not do quite what they want: +it finds some non-ISO practices, but not all---only those for which +ISO C @emph{requires} a diagnostic, and some others for which +diagnostics have been added. + +A feature to report any failure to conform to ISO C might be useful in +some instances, but would require considerable additional work and would +be quite different from @option{-pedantic}. We don't have plans to +support such a feature in the near future. + +Where the standard specified with @option{-std} represents a GNU +extended dialect of C, such as @samp{gnu89} or @samp{gnu99}, there is a +corresponding @dfn{base standard}, the version of ISO C on which the GNU +extended dialect is based. Warnings from @option{-pedantic} are given +where they are required by the base standard. (It would not make sense +for such warnings to be given only for features not in the specified GNU +C dialect, since by definition the GNU dialects of C include all +features the compiler supports with the given option, and there would be +nothing to warn about.) + +@item -pedantic-errors +@opindex pedantic-errors +Like @option{-pedantic}, except that errors are produced rather than +warnings. + +@item -w +@opindex w +Inhibit all warning messages. + +@item -Wno-import +@opindex Wno-import +Inhibit warning messages about the use of @samp{#import}. + +@c APPLE LOCAL begin -Wno-#warnings +@item -Wno-#warnings +@opindex Wno-#warnings +Inhibit warning messages issued by @samp{#warning}. +@c APPLE LOCAL end -Wno-#warnings + +@c APPLE LOCAL begin -Wextra-tokens 2001-08-02 --sts ** +@item -Wextra-tokens +@opindex Wextra-tokens +Warn about extra tokens at the end of prepreprocessor directives. (APPLE ONLY) +@c APPLE LOCAL end -Wextra-tokens 2001-08-02 --sts ** + +@c APPLE LOCAL begin -Wnewline-eof 2001-08-23 --sts ** +@item -Wnewline-eof +@opindex Wnewline-eof +Warn about files missing a newline at the end of the file. (APPLE ONLY) +@c APPLE LOCAL end -Wnewline-eof 2001-08-23 --sts ** + +@c APPLE LOCAL begin -Wno-altivec-long-deprecated --ilr ** +@item -Wno-altivec-long-deprecated +@opindex Wno-altivec-long-deprecated +Do not warn about the use of the deprecated 'long' keyword in +AltiVec data types. (APPLE ONLY) +@c APPLE LOCAL end -Wno-altivec-long-deprecated --ilr ** + +@item -Wchar-subscripts +@opindex Wchar-subscripts +Warn if an array subscript has type @code{char}. This is a common cause +of error, as programmers often forget that this type is signed on some +machines. +This warning is enabled by @option{-Wall}. + +@item -Wcomment +@opindex Wcomment +Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*} +comment, or whenever a Backslash-Newline appears in a @samp{//} comment. +This warning is enabled by @option{-Wall}. + +@item -Wfatal-errors +@opindex Wfatal-errors +This option causes the compiler to abort compilation on the first error +occurred rather than trying to keep going and printing further error +messages. + +@c APPLE LOCAL begin default to Wformat-security 5764921 +@item -Wno-format +@opindex Wno-format +@c APPLE LOCAL end default to Wformat-security 5764921 +@opindex ffreestanding +@opindex fno-builtin +Check calls to @code{printf} and @code{scanf}, etc., to make sure that +the arguments supplied have types appropriate to the format string +specified, and that the conversions specified in the format string make +sense. This includes standard functions, and others specified by format +attributes (@pxref{Function Attributes}), in the @code{printf}, +@code{scanf}, @code{strftime} and @code{strfmon} (an X/Open extension, +not in the C standard) families (or other target-specific families). +Which functions are checked without format attributes having been +specified depends on the standard version selected, and such checks of +functions without the attribute specified are disabled by +@option{-ffreestanding} or @option{-fno-builtin}. + +The formats are checked against the format features supported by GNU +libc version 2.2. These include all ISO C90 and C99 features, as well +as features from the Single Unix Specification and some BSD and GNU +extensions. Other library implementations may not support all these +features; GCC does not support warning about features that go beyond a +particular library's limitations. However, if @option{-pedantic} is used +with @option{-Wformat}, warnings will be given about format features not +in the selected standard version (but not for @code{strfmon} formats, +since those are not in any version of the C standard). @xref{C Dialect +Options,,Options Controlling C Dialect}. + +Since @option{-Wformat} also checks for null format arguments for +several functions, @option{-Wformat} also implies @option{-Wnonnull}. + +@option{-Wformat} is included in @option{-Wall}. For more control over some +aspects of format checking, the options @option{-Wformat-y2k}, +@option{-Wno-format-extra-args}, @option{-Wno-format-zero-length}, +@option{-Wformat-nonliteral}, @option{-Wformat-security}, and +@option{-Wformat=2} are available, but are not included in @option{-Wall}. + +@item -Wformat-y2k +@opindex Wformat-y2k +If @option{-Wformat} is specified, also warn about @code{strftime} +formats which may yield only a two-digit year. + +@item -Wno-format-extra-args +@opindex Wno-format-extra-args +If @option{-Wformat} is specified, do not warn about excess arguments to a +@code{printf} or @code{scanf} format function. The C standard specifies +that such arguments are ignored. + +Where the unused arguments lie between used arguments that are +specified with @samp{$} operand number specifications, normally +warnings are still given, since the implementation could not know what +type to pass to @code{va_arg} to skip the unused arguments. However, +in the case of @code{scanf} formats, this option will suppress the +warning if the unused arguments are all pointers, since the Single +Unix Specification says that such unused arguments are allowed. + +@item -Wno-format-zero-length +@opindex Wno-format-zero-length +If @option{-Wformat} is specified, do not warn about zero-length formats. +The C standard specifies that zero-length formats are allowed. + +@item -Wformat-nonliteral +@opindex Wformat-nonliteral +If @option{-Wformat} is specified, also warn if the format string is not a +string literal and so cannot be checked, unless the format function +takes its format arguments as a @code{va_list}. + +@c APPLE LOCAL begin default to Wformat-security 5764921 +@item -Wno-format-security +@opindex Wno-format-security +@c APPLE LOCAL end default to Wformat-security 5764921 +If @option{-Wformat} is specified, also warn about uses of format +functions that represent possible security problems. At present, this +warns about calls to @code{printf} and @code{scanf} functions where the +format string is not a string literal and there are no format arguments, +as in @code{printf (foo);}. This may be a security hole if the format +string came from untrusted input and contains @samp{%n}. (This is +currently a subset of what @option{-Wformat-nonliteral} warns about, but +in future warnings may be added to @option{-Wformat-security} that are not +included in @option{-Wformat-nonliteral}.) + +@item -Wformat=2 +@opindex Wformat=2 +Enable @option{-Wformat} plus format checks not included in +@option{-Wformat}. Currently equivalent to @samp{-Wformat +-Wformat-nonliteral -Wformat-security -Wformat-y2k}. + +@item -Wnonnull +@opindex Wnonnull +Warn about passing a null pointer for arguments marked as +requiring a non-null value by the @code{nonnull} function attribute. + +@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It +can be disabled with the @option{-Wno-nonnull} option. + +@c APPLE LOCAL begin Wglobal-constructors 6324584 +@item -Wglobal-constructors +@opindex Wglobal-constructors +Warn about namespace scope data that requires construction or +destruction, or functions that use the constructor attribute or the +destructor attribute. Additionally warn if the Objective-C GNU +runtime is used to initialize various metadata. +@c APPLE LOCAL end Wglobal-constructors 6324584 + +@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)} +@opindex Winit-self +Warn about uninitialized variables which are initialized with themselves. +Note this option can only be used with the @option{-Wuninitialized} option, +which in turn only works with @option{-O1} and above. + +For example, GCC will warn about @code{i} being uninitialized in the +following snippet only when @option{-Winit-self} has been specified: +@smallexample +@group +int f() +@{ + int i = i; + return i; +@} +@end group +@end smallexample + +@item -Wimplicit-int +@opindex Wimplicit-int +Warn when a declaration does not specify a type. +This warning is enabled by @option{-Wall}. + +@item -Wimplicit-function-declaration +@itemx -Werror-implicit-function-declaration +@opindex Wimplicit-function-declaration +@opindex Werror-implicit-function-declaration +Give a warning (or error) whenever a function is used before being +declared. The form @option{-Wno-error-implicit-function-declaration} +is not supported. +This warning is enabled by @option{-Wall} (as a warning, not an error). + +@item -Wimplicit +@opindex Wimplicit +Same as @option{-Wimplicit-int} and @option{-Wimplicit-function-declaration}. +This warning is enabled by @option{-Wall}. + +@item -Wmain +@opindex Wmain +Warn if the type of @samp{main} is suspicious. @samp{main} should be a +function with external linkage, returning int, taking either zero +arguments, two, or three arguments of appropriate types. +This warning is enabled by @option{-Wall}. + +@item -Wmissing-braces +@opindex Wmissing-braces +Warn if an aggregate or union initializer is not fully bracketed. In +the following example, the initializer for @samp{a} is not fully +bracketed, but that for @samp{b} is fully bracketed. + +@smallexample +int a[2][2] = @{ 0, 1, 2, 3 @}; +int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @}; +@end smallexample + +This warning is enabled by @option{-Wall}. + +@item -Wmissing-include-dirs @r{(C, C++, Objective-C and Objective-C++ only)} +@opindex Wmissing-include-dirs +Warn if a user-supplied include directory does not exist. + +@item -Wparentheses +@opindex Wparentheses +Warn if parentheses are omitted in certain contexts, such +as when there is an assignment in a context where a truth value +is expected, or when operators are nested whose precedence people +often get confused about. Only the warning for an assignment used as +a truth value is supported when compiling C++; the other warnings are +only supported when compiling C@. + +Also warn if a comparison like @samp{x<=y<=z} appears; this is +equivalent to @samp{(x<=y ? 1 : 0) <= z}, which is a different +interpretation from that of ordinary mathematical notation. + +Also warn about constructions where there may be confusion to which +@code{if} statement an @code{else} branch belongs. Here is an example of +such a case: + +@smallexample +@group +@{ + if (a) + if (b) + foo (); + else + bar (); +@} +@end group +@end smallexample + +In C, every @code{else} branch belongs to the innermost possible @code{if} +statement, which in this example is @code{if (b)}. This is often not +what the programmer expected, as illustrated in the above example by +indentation the programmer chose. When there is the potential for this +confusion, GCC will issue a warning when this flag is specified. +To eliminate the warning, add explicit braces around the innermost +@code{if} statement so there is no way the @code{else} could belong to +the enclosing @code{if}. The resulting code would look like this: + +@smallexample +@group +@{ + if (a) + @{ + if (b) + foo (); + else + bar (); + @} +@} +@end group +@end smallexample + +This warning is enabled by @option{-Wall}. + +@item -Wsequence-point +@opindex Wsequence-point +Warn about code that may have undefined semantics because of violations +of sequence point rules in the C and C++ standards. + +The C and C++ standards defines the order in which expressions in a C/C++ +program are evaluated in terms of @dfn{sequence points}, which represent +a partial ordering between the execution of parts of the program: those +executed before the sequence point, and those executed after it. These +occur after the evaluation of a full expression (one which is not part +of a larger expression), after the evaluation of the first operand of a +@code{&&}, @code{||}, @code{? :} or @code{,} (comma) operator, before a +function is called (but after the evaluation of its arguments and the +expression denoting the called function), and in certain other places. +Other than as expressed by the sequence point rules, the order of +evaluation of subexpressions of an expression is not specified. All +these rules describe only a partial order rather than a total order, +since, for example, if two functions are called within one expression +with no sequence point between them, the order in which the functions +are called is not specified. However, the standards committee have +ruled that function calls do not overlap. + +It is not specified when between sequence points modifications to the +values of objects take effect. Programs whose behavior depends on this +have undefined behavior; the C and C++ standards specify that ``Between +the previous and next sequence point an object shall have its stored +value modified at most once by the evaluation of an expression. +Furthermore, the prior value shall be read only to determine the value +to be stored.''. If a program breaks these rules, the results on any +particular implementation are entirely unpredictable. + +Examples of code with undefined behavior are @code{a = a++;}, @code{a[n] += b[n++]} and @code{a[i++] = i;}. Some more complicated cases are not +diagnosed by this option, and it may give an occasional false positive +result, but in general it has been found fairly effective at detecting +this sort of problem in programs. + +The standard is worded confusingly, therefore there is some debate +over the precise meaning of the sequence point rules in subtle cases. +Links to discussions of the problem, including proposed formal +definitions, may be found on the GCC readings page, at +@w{@uref{http://gcc.gnu.org/readings.html}}. + +This warning is enabled by @option{-Wall} for C and C++. + +@item -Wreturn-type +@opindex Wreturn-type +Warn whenever a function is defined with a return-type that defaults to +@code{int}. Also warn about any @code{return} statement with no +return-value in a function whose return-type is not @code{void}. + +For C, also warn if the return type of a function has a type qualifier +such as @code{const}. Such a type qualifier has no effect, since the +value returned by a function is not an lvalue. ISO C prohibits +qualified @code{void} return types on function definitions, so such +return types always receive a warning even without this option. + +For C++, a function without return type always produces a diagnostic +message, even when @option{-Wno-return-type} is specified. The only +exceptions are @samp{main} and functions defined in system headers. + +This warning is enabled by @option{-Wall}. + +@item -Wswitch +@opindex Wswitch +Warn whenever a @code{switch} statement has an index of enumerated type +and lacks a @code{case} for one or more of the named codes of that +enumeration. (The presence of a @code{default} label prevents this +warning.) @code{case} labels outside the enumeration range also +provoke warnings when this option is used. +This warning is enabled by @option{-Wall}. + +@item -Wswitch-default +@opindex Wswitch-switch +Warn whenever a @code{switch} statement does not have a @code{default} +case. + +@item -Wswitch-enum +@opindex Wswitch-enum +Warn whenever a @code{switch} statement has an index of enumerated type +and lacks a @code{case} for one or more of the named codes of that +enumeration. @code{case} labels outside the enumeration range also +provoke warnings when this option is used. + +@item -Wtrigraphs +@opindex Wtrigraphs +Warn if any trigraphs are encountered that might change the meaning of +the program (trigraphs within comments are not warned about). +This warning is enabled by @option{-Wall}. + +@item -Wunused-function +@opindex Wunused-function +Warn whenever a static function is declared but not defined or a +non-inline static function is unused. +This warning is enabled by @option{-Wall}. + +@item -Wunused-label +@opindex Wunused-label +Warn whenever a label is declared but not used. +This warning is enabled by @option{-Wall}. + +To suppress this warning use the @samp{unused} attribute +(@pxref{Variable Attributes}). + +@item -Wunused-parameter +@opindex Wunused-parameter +Warn whenever a function parameter is unused aside from its declaration. + +To suppress this warning use the @samp{unused} attribute +(@pxref{Variable Attributes}). + +@item -Wunused-variable +@opindex Wunused-variable +Warn whenever a local variable or non-constant static variable is unused +aside from its declaration. +This warning is enabled by @option{-Wall}. + +To suppress this warning use the @samp{unused} attribute +(@pxref{Variable Attributes}). + +@item -Wunused-value +@opindex Wunused-value +Warn whenever a statement computes a result that is explicitly not used. +This warning is enabled by @option{-Wall}. + +To suppress this warning cast the expression to @samp{void}. + +@item -Wunused +@opindex Wunused +All the above @option{-Wunused} options combined. + +In order to get a warning about an unused function parameter, you must +either specify @samp{-Wextra -Wunused} (note that @samp{-Wall} implies +@samp{-Wunused}), or separately specify @option{-Wunused-parameter}. + +@item -Wuninitialized +@opindex Wuninitialized +Warn if an automatic variable is used without first being initialized or +if a variable may be clobbered by a @code{setjmp} call. + +These warnings are possible only in optimizing compilation, +because they require data flow information that is computed only +when optimizing. If you do not specify @option{-O}, you will not get +these warnings. Instead, GCC will issue a warning about @option{-Wuninitialized} +requiring @option{-O}. + +If you want to warn about code which uses the uninitialized value of the +variable in its own initializer, use the @option{-Winit-self} option. + +These warnings occur for individual uninitialized or clobbered +elements of structure, union or array variables as well as for +variables which are uninitialized or clobbered as a whole. They do +not occur for variables or elements declared @code{volatile}. Because +these warnings depend on optimization, the exact variables or elements +for which there are warnings will depend on the precise optimization +options and version of GCC used. + +Note that there may be no warning about a variable that is used only +to compute a value that itself is never used, because such +computations may be deleted by data flow analysis before the warnings +are printed. + +These warnings are made optional because GCC is not smart +enough to see all the reasons why the code might be correct +despite appearing to have an error. Here is one example of how +this can happen: + +@smallexample +@group +@{ + int x; + switch (y) + @{ + case 1: x = 1; + break; + case 2: x = 4; + break; + case 3: x = 5; + @} + foo (x); +@} +@end group +@end smallexample + +@noindent +If the value of @code{y} is always 1, 2 or 3, then @code{x} is +always initialized, but GCC doesn't know this. Here is +another common case: + +@smallexample +@{ + int save_y; + if (change_y) save_y = y, y = new_y; + @dots{} + if (change_y) y = save_y; +@} +@end smallexample + +@noindent +This has no bug because @code{save_y} is used only if it is set. + +@cindex @code{longjmp} warnings +This option also warns when a non-volatile automatic variable might be +changed by a call to @code{longjmp}. These warnings as well are possible +only in optimizing compilation. + +The compiler sees only the calls to @code{setjmp}. It cannot know +where @code{longjmp} will be called; in fact, a signal handler could +call it at any point in the code. As a result, you may get a warning +even when there is in fact no problem because @code{longjmp} cannot +in fact be called at the place which would cause a problem. + +Some spurious warnings can be avoided if you declare all the functions +you use that never return as @code{noreturn}. @xref{Function +Attributes}. + +This warning is enabled by @option{-Wall}. + +@item -Wunknown-pragmas +@opindex Wunknown-pragmas +@cindex warning for unknown pragmas +@cindex unknown pragmas, warning +@cindex pragmas, warning of unknown +Warn when a #pragma directive is encountered which is not understood by +GCC@. If this command line option is used, warnings will even be issued +for unknown pragmas in system header files. This is not the case if +the warnings were only enabled by the @option{-Wall} command line option. + +@item -Wno-pragmas +@opindex Wno-pragmas +@opindex Wpragmas +Do not warn about misuses of pragmas, such as incorrect parameters, +invalid syntax, or conflicts between pragmas. See also +@samp{-Wunknown-pragmas}. + +@item -Wstrict-aliasing +@opindex Wstrict-aliasing +This option is only active when @option{-fstrict-aliasing} is active. +It warns about code which might break the strict aliasing rules that the +compiler is using for optimization. The warning does not catch all +cases, but does attempt to catch the more common pitfalls. It is +included in @option{-Wall}. + +@item -Wstrict-aliasing=2 +@opindex Wstrict-aliasing=2 +This option is only active when @option{-fstrict-aliasing} is active. +It warns about code which might break the strict aliasing rules that the +compiler is using for optimization. This warning catches more cases than +@option{-Wstrict-aliasing}, but it will also give a warning for some ambiguous +cases that are safe. + +@item -Wstrict-overflow +@item -Wstrict-overflow=@var{n} +@opindex Wstrict-overflow +This option is only active when @option{-fstrict-overflow} is active. +It warns about cases where the compiler optimizes based on the +assumption that signed overflow does not occur. Note that it does not +warn about all cases where the code might overflow: it only warns +about cases where the compiler implements some optimization. Thus +this warning depends on the optimization level. + +An optimization which assumes that signed overflow does not occur is +perfectly safe if the values of the variables involved are such that +overflow never does, in fact, occur. Therefore this warning can +easily give a false positive: a warning about code which is not +actually a problem. To help focus on important issues, several +warning levels are defined. No warnings are issued for the use of +undefined signed overflow when estimating how many iterations a loop +will require, in particular when determining whether a loop will be +executed at all. + +@c APPLE LOCAL mainline man page 6365204 +@table @gcctabopt +@item -Wstrict-overflow=1 +Warn about cases which are both questionable and easy to avoid. For +example: @code{x + 1 > x}; with @option{-fstrict-overflow}, the +compiler will simplify this to @code{1}. This level of +@option{-Wstrict-overflow} is enabled by @option{-Wall}; higher levels +are not, and must be explicitly requested. + +@item -Wstrict-overflow=2 +Also warn about other cases where a comparison is simplified to a +constant. For example: @code{abs (x) >= 0}. This can only be +simplified when @option{-fstrict-overflow} is in effect, because +@code{abs (INT_MIN)} overflows to @code{INT_MIN}, which is less than +zero. @option{-Wstrict-overflow} (with no level) is the same as +@option{-Wstrict-overflow=2}. + +@item -Wstrict-overflow=3 +Also warn about other cases where a comparison is simplified. For +example: @code{x + 1 > 1} will be simplified to @code{x > 0}. + +@item -Wstrict-overflow=4 +Also warn about other simplifications not covered by the above cases. +For example: @code{(x * 10) / 5} will be simplified to @code{x * 2}. + +@item -Wstrict-overflow=5 +Also warn about cases where the compiler reduces the magnitude of a +constant involved in a comparison. For example: @code{x + 2 > y} will +be simplified to @code{x + 1 >= y}. This is reported only at the +highest warning level because this simplification applies to many +comparisons, so this warning level will give a very large number of +false positives. +@end table + +@item -Wall +@opindex Wall +All of the above @samp{-W} options combined. This enables all the +warnings about constructions that some users consider questionable, and +that are easy to avoid (or modify to prevent the warning), even in +conjunction with macros. This also enables some language-specific +warnings described in @ref{C++ Dialect Options} and +@ref{Objective-C and Objective-C++ Dialect Options}. +@c APPLE LOCAL begin -Wmost +@item -Wmost +@opindex Wmost +This is equivalent to -Wall -Wno-parentheses. (APPLE ONLY) +@end table +@c APPLE LOCAL end -Wmost + +The following @option{-W@dots{}} options are not implied by @option{-Wall}. +Some of them warn about constructions that users generally do not +consider questionable, but which occasionally you might wish to check +for; others warn about constructions that are necessary or hard to avoid +in some cases, and there is no simple way to modify the code to suppress +the warning. + +@table @gcctabopt +@item -Wextra +@opindex W +@opindex Wextra +(This option used to be called @option{-W}. The older name is still +supported, but the newer name is more descriptive.) Print extra warning +messages for these events: + +@itemize @bullet +@item +A function can return either with or without a value. (Falling +off the end of the function body is considered returning without +a value.) For example, this function would evoke such a +warning: + +@smallexample +@group +foo (a) +@{ + if (a > 0) + return a; +@} +@end group +@end smallexample + +@item +An expression-statement or the left-hand side of a comma expression +contains no side effects. +To suppress the warning, cast the unused expression to void. +For example, an expression such as @samp{x[i,j]} will cause a warning, +but @samp{x[(void)i,j]} will not. + +@item +An unsigned value is compared against zero with @samp{<} or @samp{>=}. + +@item +Storage-class specifiers like @code{static} are not the first things in +a declaration. According to the C Standard, this usage is obsolescent. + +@item +If @option{-Wall} or @option{-Wunused} is also specified, warn about unused +arguments. + +@item +A comparison between signed and unsigned values could produce an +incorrect result when the signed value is converted to unsigned. +(But don't warn if @option{-Wno-sign-compare} is also specified.) + +@item +An aggregate has an initializer which does not initialize all members. +This warning can be independently controlled by +@option{-Wmissing-field-initializers}. + +@item +An initialized field without side effects is overridden when using +designated initializers (@pxref{Designated Inits, , Designated +Initializers}). This warning can be independently controlled by +@option{-Woverride-init}. + +@item +A function parameter is declared without a type specifier in K&R-style +functions: + +@smallexample +void foo(bar) @{ @} +@end smallexample + +@item +An empty body occurs in an @samp{if} or @samp{else} statement. + +@c APPLE LOCAL begin mainline +@c APPLE LOCAL begin pod error 6089368 +@item +(C++ only) An empty body occurs in a @samp{while} or @samp{for} statement with no +@c APPLE LOCAL end pod error 6089368 +whitespacing before the semicolon. This warning can be independently +controlled by @option{-Wempty-body}. +@c APPLE LOCAL end mainline + +@item +A pointer is compared against integer zero with @samp{<}, @samp{<=}, +@samp{>}, or @samp{>=}. + +@item +A variable might be changed by @samp{longjmp} or @samp{vfork}. + +@c APPLE LOCAL begin pod error 6089368 +@item +(C++ only) An enumerator and a non-enumerator both appear in a conditional expression. + +@item +(C++ only) A non-static reference or non-static @samp{const} member appears in a +class without constructors. + +@item +(C++ only) Ambiguous virtual bases. + +@item +(C++ only) Subscripting an array which has been declared @samp{register}. + +@item +(C++ only) Taking the address of a variable which has been declared @samp{register}. + +@item +(C++ only) A base class is not initialized in a derived class' copy constructor. +@c APPLE LOCAL end pod error 6089368 +@end itemize + +@item -Wno-div-by-zero +@opindex Wno-div-by-zero +@opindex Wdiv-by-zero +Do not warn about compile-time integer division by zero. Floating point +division by zero is not warned about, as it can be a legitimate way of +obtaining infinities and NaNs. + +@item -Wsystem-headers +@opindex Wsystem-headers +@cindex warnings from system headers +@cindex system headers, warnings from +Print warning messages for constructs found in system header files. +Warnings from system headers are normally suppressed, on the assumption +that they usually do not indicate real problems and would only make the +compiler output harder to read. Using this command line option tells +GCC to emit warnings from system headers as if they occurred in user +code. However, note that using @option{-Wall} in conjunction with this +option will @emph{not} warn about unknown pragmas in system +headers---for that, @option{-Wunknown-pragmas} must also be used. + +@item -Wfloat-equal +@opindex Wfloat-equal +Warn if floating point values are used in equality comparisons. + +The idea behind this is that sometimes it is convenient (for the +programmer) to consider floating-point values as approximations to +infinitely precise real numbers. If you are doing this, then you need +to compute (by analyzing the code, or in some other way) the maximum or +likely maximum error that the computation introduces, and allow for it +when performing comparisons (and when producing output, but that's a +different problem). In particular, instead of testing for equality, you +would check to see whether the two values have ranges that overlap; and +this is done with the relational operators, so equality comparisons are +probably mistaken. + +@c APPLE LOCAL begin -Wfour-char-constants +@item -Wfour-char-constants +@opindex Wfour-char-constants +Warn about four char constants, e.g. OSType 'APPL'. This warning is +disabled by default. +@c APPLE LOCAL end + +@item -Wtraditional @r{(C only)} +@opindex Wtraditional +Warn about certain constructs that behave differently in traditional and +ISO C@. Also warn about ISO C constructs that have no traditional C +equivalent, and/or problematic constructs which should be avoided. + +@itemize @bullet +@item +Macro parameters that appear within string literals in the macro body. +In traditional C macro replacement takes place within string literals, +but does not in ISO C@. + +@item +In traditional C, some preprocessor directives did not exist. +Traditional preprocessors would only consider a line to be a directive +if the @samp{#} appeared in column 1 on the line. Therefore +@option{-Wtraditional} warns about directives that traditional C +understands but would ignore because the @samp{#} does not appear as the +first character on the line. It also suggests you hide directives like +@samp{#pragma} not understood by traditional C by indenting them. Some +traditional implementations would not recognize @samp{#elif}, so it +suggests avoiding it altogether. + +@item +A function-like macro that appears without arguments. + +@item +The unary plus operator. + +@item +The @samp{U} integer constant suffix, or the @samp{F} or @samp{L} floating point +constant suffixes. (Traditional C does support the @samp{L} suffix on integer +constants.) Note, these suffixes appear in macros defined in the system +headers of most modern systems, e.g.@: the @samp{_MIN}/@samp{_MAX} macros in @code{<limits.h>}. +Use of these macros in user code might normally lead to spurious +warnings, however GCC's integrated preprocessor has enough context to +avoid warning in these cases. + +@item +A function declared external in one block and then used after the end of +the block. + +@item +A @code{switch} statement has an operand of type @code{long}. + +@item +A non-@code{static} function declaration follows a @code{static} one. +This construct is not accepted by some traditional C compilers. + +@item +The ISO type of an integer constant has a different width or +signedness from its traditional type. This warning is only issued if +the base of the constant is ten. I.e.@: hexadecimal or octal values, which +typically represent bit patterns, are not warned about. + +@item +Usage of ISO string concatenation is detected. + +@item +Initialization of automatic aggregates. + +@item +Identifier conflicts with labels. Traditional C lacks a separate +namespace for labels. + +@item +Initialization of unions. If the initializer is zero, the warning is +omitted. This is done under the assumption that the zero initializer in +user code appears conditioned on e.g.@: @code{__STDC__} to avoid missing +initializer warnings and relies on default initialization to zero in the +traditional C case. + +@item +Conversions by prototypes between fixed/floating point values and vice +versa. The absence of these prototypes when compiling with traditional +C would cause serious problems. This is a subset of the possible +conversion warnings, for the full set use @option{-Wconversion}. + +@item +Use of ISO C style function definitions. This warning intentionally is +@emph{not} issued for prototype declarations or variadic functions +because these ISO C features will appear in your code when using +libiberty's traditional C compatibility macros, @code{PARAMS} and +@code{VPARAMS}. This warning is also bypassed for nested functions +because that feature is already a GCC extension and thus not relevant to +traditional C compatibility. +@end itemize + +@item -Wdeclaration-after-statement @r{(C only)} +@opindex Wdeclaration-after-statement +Warn when a declaration is found after a statement in a block. This +construct, known from C++, was introduced with ISO C99 and is by default +allowed in GCC@. It is not supported by ISO C90 and was not supported by +GCC versions before GCC 3.0. @xref{Mixed Declarations}. + +@c APPLE LOCAL begin -Wdiscard-qual 4086969 +@item -Wno-discard-qual +@opindex Wno-discard-qual +This flag allows user to suppress warning that is issued when qualification +is discarded in situations like, initialization, assignment and argument +passing. +@c APPLE LOCAL end -Wdiscard-qual 4086969 + +@item -Wundef +@opindex Wundef +Warn if an undefined identifier is evaluated in an @samp{#if} directive. + +@item -Wno-endif-labels +@opindex Wno-endif-labels +@opindex Wendif-labels +Do not warn whenever an @samp{#else} or an @samp{#endif} are followed by text. + +@item -Wshadow +@opindex Wshadow +Warn whenever a local variable shadows another local variable, parameter or +global variable or whenever a built-in function is shadowed. + +@item -Wlarger-than-@var{len} +@opindex Wlarger-than +Warn whenever an object of larger than @var{len} bytes is defined. + +@item -Wunsafe-loop-optimizations +@opindex Wunsafe-loop-optimizations +Warn if the loop cannot be optimized because the compiler could not +assume anything on the bounds of the loop indices. With +@option{-funsafe-loop-optimizations} warn if the compiler made +such assumptions. + +@item -Wpointer-arith +@opindex Wpointer-arith +Warn about anything that depends on the ``size of'' a function type or +of @code{void}. GNU C assigns these types a size of 1, for +convenience in calculations with @code{void *} pointers and pointers +to functions. + +@item -Wbad-function-cast @r{(C only)} +@opindex Wbad-function-cast +Warn whenever a function call is cast to a non-matching type. +For example, warn if @code{int malloc()} is cast to @code{anything *}. + +@item -Wc++-compat +Warn about ISO C constructs that are outside of the common subset of +ISO C and ISO C++, e.g.@: request for implicit conversion from +@code{void *} to a pointer to non-@code{void} type. + +@item -Wcast-qual +@opindex Wcast-qual +Warn whenever a pointer is cast so as to remove a type qualifier from +the target type. For example, warn if a @code{const char *} is cast +to an ordinary @code{char *}. + +@item -Wcast-align +@opindex Wcast-align +Warn whenever a pointer is cast such that the required alignment of the +target is increased. For example, warn if a @code{char *} is cast to +an @code{int *} on machines where integers can only be accessed at +two- or four-byte boundaries. + +@item -Wwrite-strings +@opindex Wwrite-strings +When compiling C, give string constants the type @code{const +char[@var{length}]} so that +copying the address of one into a non-@code{const} @code{char *} +pointer will get a warning; when compiling C++, warn about the +deprecated conversion from string literals to @code{char *}. This +warning, by default, is enabled for C++ programs. +These warnings will help you find at +compile time code that can try to write into a string constant, but +only if you have been very careful about using @code{const} in +declarations and prototypes. Otherwise, it will just be a nuisance; +this is why we did not make @option{-Wall} request these warnings. + +@item -Wconversion +@opindex Wconversion +Warn if a prototype causes a type conversion that is different from what +would happen to the same argument in the absence of a prototype. This +includes conversions of fixed point to floating and vice versa, and +conversions changing the width or signedness of a fixed point argument +except when the same as the default promotion. + +Also, warn if a negative integer constant expression is implicitly +converted to an unsigned type. For example, warn about the assignment +@code{x = -1} if @code{x} is unsigned. But do not warn about explicit +casts like @code{(unsigned) -1}. + +@c APPLE LOCAL begin mainline +@item -Wshorten-64-to-32 +@opindex Wshorten-64-to-32 +Warn if a value is implicitly converted from a 64 bit type to a 32 bit type. +@c APPLE LOCAL end mainline + +@c APPLE LOCAL begin mainline +@item -Wempty-body +@opindex Wempty-body +Warn if an empty body occurs in an @samp{if} or @samp{else} +statement. Additionally, in C++, warn when an empty body occurs +in a @samp{while} or @samp{for} statement with no whitespacing before +the semicolon. This warning is also enabled by @option{-Wextra}. +@c APPLE LOCAL end mainline + +@item -Wsign-compare +@opindex Wsign-compare +@cindex warning for comparison of signed and unsigned values +@cindex comparison of signed and unsigned values, warning +@cindex signed and unsigned values, comparison warning +Warn when a comparison between signed and unsigned values could produce +an incorrect result when the signed value is converted to unsigned. +This warning is also enabled by @option{-Wextra}; to get the other warnings +of @option{-Wextra} without this warning, use @samp{-Wextra -Wno-sign-compare}. + +@item -Waddress +@opindex Waddress +@opindex Wno-address +Warn about suspicious uses of memory addresses. These include using +the address of a function in a conditional expression, such as +@code{void func(void); if (func)}, and comparisons against the memory +address of a string literal, such as @code{if (x == "abc")}. Such +uses typically indicate a programmer error: the address of a function +always evaluates to true, so their use in a conditional usually +indicate that the programmer forgot the parentheses in a function +call; and comparisons against string literals result in unspecified +behavior and are not portable in C, so they usually indicate that the +programmer intended to use @code{strcmp}. This warning is enabled by +@option{-Wall}. + +@item -Waggregate-return +@opindex Waggregate-return +Warn if any functions that return structures or unions are defined or +called. (In languages where you can return an array, this also elicits +a warning.) + +@item -Wno-attributes +@opindex Wno-attributes +@opindex Wattributes +Do not warn if an unexpected @code{__attribute__} is used, such as +unrecognized attributes, function attributes applied to variables, +etc. This will not stop errors for incorrect use of supported +attributes. + +@item -Wstrict-prototypes @r{(C only)} +@opindex Wstrict-prototypes +Warn if a function is declared or defined without specifying the +argument types. (An old-style function definition is permitted without +a warning if preceded by a declaration which specifies the argument +types.) + +@item -Wold-style-definition @r{(C only)} +@opindex Wold-style-definition +Warn if an old-style function definition is used. A warning is given +even if there is a previous prototype. + +@c APPLE LOCAL warn missing prototype 6261539 +@item -Wmissing-prototypes +@opindex Wmissing-prototypes +Warn if a global function is defined without a previous prototype +declaration. This warning is issued even if the definition itself +provides a prototype. The aim is to detect global functions that fail +to be declared in header files. + +@item -Wmissing-declarations @r{(C only)} +@opindex Wmissing-declarations +Warn if a global function is defined without a previous declaration. +Do so even if the definition itself provides a prototype. +Use this option to detect global functions that are not declared in +header files. + +@item -Wmissing-field-initializers +@opindex Wmissing-field-initializers +@opindex W +@opindex Wextra +Warn if a structure's initializer has some fields missing. For +example, the following code would cause such a warning, because +@code{x.h} is implicitly zero: + +@smallexample +struct s @{ int f, g, h; @}; +struct s x = @{ 3, 4 @}; +@end smallexample + +This option does not warn about designated initializers, so the following +modification would not trigger a warning: + +@smallexample +struct s @{ int f, g, h; @}; +struct s x = @{ .f = 3, .g = 4 @}; +@end smallexample + +This warning is included in @option{-Wextra}. To get other @option{-Wextra} +warnings without this one, use @samp{-Wextra -Wno-missing-field-initializers}. + +@item -Wmissing-noreturn +@opindex Wmissing-noreturn +Warn about functions which might be candidates for attribute @code{noreturn}. +Note these are only possible candidates, not absolute ones. Care should +be taken to manually verify functions actually do not ever return before +adding the @code{noreturn} attribute, otherwise subtle code generation +bugs could be introduced. You will not get a warning for @code{main} in +hosted C environments. + +@item -Wmissing-format-attribute +@opindex Wmissing-format-attribute +@opindex Wformat +Warn about function pointers which might be candidates for @code{format} +attributes. Note these are only possible candidates, not absolute ones. +GCC will guess that function pointers with @code{format} attributes that +are used in assignment, initialization, parameter passing or return +statements should have a corresponding @code{format} attribute in the +resulting type. I.e.@: the left-hand side of the assignment or +initialization, the type of the parameter variable, or the return type +of the containing function respectively should also have a @code{format} +attribute to avoid the warning. + +GCC will also warn about function definitions which might be +candidates for @code{format} attributes. Again, these are only +possible candidates. GCC will guess that @code{format} attributes +might be appropriate for any function that calls a function like +@code{vprintf} or @code{vscanf}, but this might not always be the +case, and some functions for which @code{format} attributes are +appropriate may not be detected. + +@item -Wno-multichar +@opindex Wno-multichar +@opindex Wmultichar +@c APPLE LOCAL begin -Wfour-char-constants +Do not warn if a multicharacter constant (@samp{'FOO'}) is used. +Usually they indicate a typo in the user's code, as they have +implementation-defined values, and should not be used in portable code. +This flag does not control warning for a constant with four characters, +use -Wfour-char-constants instead. +@c APPLE LOCAL end -Wfour-char-constants + +@item -Wnormalized=<none|id|nfc|nfkc> +@opindex Wnormalized +@cindex NFC +@cindex NFKC +@cindex character set, input normalization +In ISO C and ISO C++, two identifiers are different if they are +different sequences of characters. However, sometimes when characters +outside the basic ASCII character set are used, you can have two +different character sequences that look the same. To avoid confusion, +the ISO 10646 standard sets out some @dfn{normalization rules} which +when applied ensure that two sequences that look the same are turned into +the same sequence. GCC can warn you if you are using identifiers which +have not been normalized; this option controls that warning. + +There are four levels of warning that GCC supports. The default is +@option{-Wnormalized=nfc}, which warns about any identifier which is +not in the ISO 10646 ``C'' normalized form, @dfn{NFC}. NFC is the +recommended form for most uses. + +Unfortunately, there are some characters which ISO C and ISO C++ allow +in identifiers that when turned into NFC aren't allowable as +identifiers. That is, there's no way to use these symbols in portable +ISO C or C++ and have all your identifiers in NFC. +@option{-Wnormalized=id} suppresses the warning for these characters. +It is hoped that future versions of the standards involved will correct +this, which is why this option is not the default. + +You can switch the warning off for all characters by writing +@option{-Wnormalized=none}. You would only want to do this if you +were using some other normalization scheme (like ``D''), because +otherwise you can easily create bugs that are literally impossible to see. + +Some characters in ISO 10646 have distinct meanings but look identical +in some fonts or display methodologies, especially once formatting has +been applied. For instance @code{\u207F}, ``SUPERSCRIPT LATIN SMALL +LETTER N'', will display just like a regular @code{n} which has been +placed in a superscript. ISO 10646 defines the @dfn{NFKC} +normalization scheme to convert all these into a standard form as +well, and GCC will warn if your code is not in NFKC if you use +@option{-Wnormalized=nfkc}. This warning is comparable to warning +about every identifier that contains the letter O because it might be +confused with the digit 0, and so is not the default, but may be +useful as a local coding convention if the programming environment is +unable to be fixed to display these characters distinctly. + +@item -Wno-deprecated-declarations +@opindex Wno-deprecated-declarations +Do not warn about uses of functions (@pxref{Function Attributes}), +variables (@pxref{Variable Attributes}), and types (@pxref{Type +Attributes}) marked as deprecated by using the @code{deprecated} +attribute. + +@item -Wno-overflow +@opindex Wno-overflow +Do not warn about compile-time overflow in constant expressions. + +@item -Woverride-init +@opindex Woverride-init +@opindex W +@opindex Wextra +Warn if an initialized field without side effects is overridden when +using designated initializers (@pxref{Designated Inits, , Designated +Initializers}). + +This warning is included in @option{-Wextra}. To get other +@option{-Wextra} warnings without this one, use @samp{-Wextra +-Wno-override-init}. + +@item -Wpacked +@opindex Wpacked +Warn if a structure is given the packed attribute, but the packed +attribute has no effect on the layout or size of the structure. +Such structures may be mis-aligned for little benefit. For +instance, in this code, the variable @code{f.x} in @code{struct bar} +will be misaligned even though @code{struct bar} does not itself +have the packed attribute: + +@smallexample +@group +struct foo @{ + int x; + char a, b, c, d; +@} __attribute__((packed)); +struct bar @{ + char z; + struct foo f; +@}; +@end group +@end smallexample + +@item -Wpadded +@opindex Wpadded +Warn if padding is included in a structure, either to align an element +of the structure or to align the whole structure. Sometimes when this +happens it is possible to rearrange the fields of the structure to +reduce the padding and so make the structure smaller. + +@item -Wredundant-decls +@opindex Wredundant-decls +Warn if anything is declared more than once in the same scope, even in +cases where multiple declaration is valid and changes nothing. + +@item -Wnested-externs @r{(C only)} +@opindex Wnested-externs +Warn if an @code{extern} declaration is encountered within a function. + +@item -Wunreachable-code +@opindex Wunreachable-code +Warn if the compiler detects that code will never be executed. + +This option is intended to warn when the compiler detects that at +least a whole line of source code will never be executed, because +some condition is never satisfied or because it is after a +procedure that never returns. + +It is possible for this option to produce a warning even though there +are circumstances under which part of the affected line can be executed, +so care should be taken when removing apparently-unreachable code. + +For instance, when a function is inlined, a warning may mean that the +line is unreachable in only one inlined copy of the function. + +This option is not made part of @option{-Wall} because in a debugging +version of a program there is often substantial code which checks +correct functioning of the program and is, hopefully, unreachable +because the program does work. Another common use of unreachable +code is to provide behavior which is selectable at compile-time. + +@item -Winline +@opindex Winline +Warn if a function can not be inlined and it was declared as inline. +Even with this option, the compiler will not warn about failures to +inline functions declared in system headers. + +The compiler uses a variety of heuristics to determine whether or not +to inline a function. For example, the compiler takes into account +the size of the function being inlined and the amount of inlining +that has already been done in the current function. Therefore, +seemingly insignificant changes in the source program can cause the +warnings produced by @option{-Winline} to appear or disappear. + +@item -Wno-invalid-offsetof @r{(C++ only)} +@opindex Wno-invalid-offsetof +Suppress warnings from applying the @samp{offsetof} macro to a non-POD +type. According to the 1998 ISO C++ standard, applying @samp{offsetof} +to a non-POD type is undefined. In existing C++ implementations, +however, @samp{offsetof} typically gives meaningful results even when +applied to certain kinds of non-POD types. (Such as a simple +@samp{struct} that fails to be a POD type only by virtue of having a +constructor.) This flag is for users who are aware that they are +writing nonportable code and who have deliberately chosen to ignore the +warning about it. + +The restrictions on @samp{offsetof} may be relaxed in a future version +of the C++ standard. + +@item -Wno-int-to-pointer-cast @r{(C only)} +@opindex Wno-int-to-pointer-cast +Suppress warnings from casts to pointer type of an integer of a +different size. + +@item -Wno-pointer-to-int-cast @r{(C only)} +@opindex Wno-pointer-to-int-cast +Suppress warnings from casts from a pointer to an integer type of a +different size. + +@item -Winvalid-pch +@opindex Winvalid-pch +Warn if a precompiled header (@pxref{Precompiled Headers}) is found in +the search path but can't be used. + +@item -Wlong-long +@opindex Wlong-long +@opindex Wno-long-long +Warn if @samp{long long} type is used. This is default. To inhibit +the warning messages, use @option{-Wno-long-long}. Flags +@option{-Wlong-long} and @option{-Wno-long-long} are taken into account +only when @option{-pedantic} flag is used. + +@item -Wvariadic-macros +@opindex Wvariadic-macros +@opindex Wno-variadic-macros +Warn if variadic macros are used in pedantic ISO C90 mode, or the GNU +alternate syntax when in pedantic ISO C99 mode. This is default. +To inhibit the warning messages, use @option{-Wno-variadic-macros}. + +@item -Wvolatile-register-var +@opindex Wvolatile-register-var +@opindex Wno-volatile-register-var +Warn if a register variable is declared volatile. The volatile +modifier does not inhibit all optimizations that may eliminate reads +and/or writes to register variables. + +@item -Wdisabled-optimization +@opindex Wdisabled-optimization +Warn if a requested optimization pass is disabled. This warning does +not generally indicate that there is anything wrong with your code; it +merely indicates that GCC's optimizers were unable to handle the code +effectively. Often, the problem is that your code is too big or too +complex; GCC will refuse to optimize programs when the optimization +itself is likely to take inordinate amounts of time. + +@item -Wpointer-sign +@opindex Wpointer-sign +@opindex Wno-pointer-sign +Warn for pointer argument passing or assignment with different signedness. +This option is only supported for C and Objective-C@. It is implied by +@option{-Wall} and by @option{-pedantic}, which can be disabled with +@option{-Wno-pointer-sign}. + +@item -Werror +@opindex Werror +Make all warnings into errors. + +@item -Werror= +@opindex Werror= +Make the specified warning into an errors. The specifier for a +warning is appended, for example @option{-Werror=switch} turns the +warnings controlled by @option{-Wswitch} into errors. This switch +takes a negative form, to be used to negate @option{-Werror} for +specific warnings, for example @option{-Wno-error=switch} makes +@option{-Wswitch} warnings not be errors, even when @option{-Werror} +is in effect. You can use the @option{-fdiagnostics-show-option} +option to have each controllable warning amended with the option which +controls it, to determine what to use with this option. + +Note that specifying @option{-Werror=}@var{foo} automatically implies +@option{-W}@var{foo}. However, @option{-Wno-error=}@var{foo} does not +imply anything. + +@item -Wstack-protector +@opindex Wstack-protector +This option is only active when @option{-fstack-protector} is active. It +warns about functions that will not be protected against stack smashing. + +@item -Woverlength-strings +@opindex Woverlength-strings +Warn about string constants which are longer than the ``minimum +maximum'' length specified in the C standard. Modern compilers +generally allow string constants which are much longer than the +standard's minimum limit, but very portable programs should avoid +using longer strings. + +The limit applies @emph{after} string constant concatenation, and does +not count the trailing NUL@. In C89, the limit was 509 characters; in +C99, it was raised to 4095. C++98 does not specify a normative +minimum maximum, so we do not diagnose overlength strings in C++@. + +This option is implied by @option{-pedantic}, and can be disabled with +@option{-Wno-overlength-strings}. +@end table + +@node Debugging Options +@section Options for Debugging Your Program or GCC +@cindex options, debugging +@cindex debugging information options + +GCC has various special options that are used for debugging +either your program or GCC: + +@table @gcctabopt +@item -g +@opindex g +Produce debugging information in the operating system's native format +(stabs, COFF, XCOFF, or DWARF 2)@. GDB can work with this debugging +information. + +On most systems that use stabs format, @option{-g} enables use of extra +debugging information that only GDB can use; this extra information +makes debugging work better in GDB but will probably make other debuggers +crash or +refuse to read the program. If you want to control for certain whether +@c APPLE LOCAL begin prune man page +to generate the extra information, use @option{-gstabs+} or @option{-gstabs} +(see below). +@c APPLE LOCAL end prune man page + +GCC allows you to use @option{-g} with +@option{-O}. The shortcuts taken by optimized code may occasionally +produce surprising results: some variables you declared may not exist +at all; flow of control may briefly move where you did not expect it; +some statements may not be executed because they compute constant +results or their values were already at hand; some statements may +execute in different places because they were moved out of loops. + +Nevertheless it proves possible to debug optimized output. This makes +it reasonable to use the optimizer for programs that might have bugs. + +The following options are useful when GCC is generated with the +capability for more than one debugging format. + +@item -ggdb +@opindex ggdb +Produce debugging information for use by GDB@. This means to use the +most expressive format available (DWARF 2, stabs, or the native format +if neither of those are supported), including GDB extensions if at all +possible. + +@item -gstabs +@opindex gstabs +Produce debugging information in stabs format (if that is supported), +without GDB extensions. This is the format used by DBX on most BSD +systems. On MIPS, Alpha and System V Release 4 systems this option +produces stabs debugging output which is not understood by DBX or SDB@. +On System V Release 4 systems this option requires the GNU assembler. + +@c APPLE LOCAL begin 4167759 +@item -flimit-debug-info +@opindex -flimit-debug-info +Limit debug information produced to reduce size of debug binary. +@c APPLE LOCAL end 4167759 + +@item -feliminate-unused-debug-symbols +@opindex feliminate-unused-debug-symbols +Produce debugging information in stabs format (if that is supported), +for only symbols that are actually used. + +@item -femit-class-debug-always +Instead of emitting debugging information for a C++ class in only one +object file, emit it in all object files using the class. This option +should be used only with debuggers that are unable to handle the way GCC +normally emits debugging information for classes because using this +option will increase the size of debugging information by as much as a +factor of two. + +@item -gstabs+ +@opindex gstabs+ +Produce debugging information in stabs format (if that is supported), +using GNU extensions understood only by the GNU debugger (GDB)@. The +use of these extensions is likely to make other debuggers crash or +refuse to read the program. + +@c APPLE LOCAL prune man page +@ignore +@item -gcoff +@opindex gcoff +Produce debugging information in COFF format (if that is supported). +This is the format used by SDB on most System V systems prior to +System V Release 4. + +@item -gxcoff +@opindex gxcoff +Produce debugging information in XCOFF format (if that is supported). +This is the format used by the DBX debugger on IBM RS/6000 systems. + +@item -gxcoff+ +@opindex gxcoff+ +Produce debugging information in XCOFF format (if that is supported), +using GNU extensions understood only by the GNU debugger (GDB)@. The +use of these extensions is likely to make other debuggers crash or +refuse to read the program, and may cause assemblers other than the GNU +assembler (GAS) to fail with an error. +@c APPLE LOCAL prune man page +@end ignore + +@item -gdwarf-2 +@opindex gdwarf-2 +Produce debugging information in DWARF version 2 format (if that is +supported). This is the format used by DBX on IRIX 6. With this +option, GCC uses features of DWARF version 3 when they are useful; +version 3 is upward compatible with version 2, but may still cause +problems for older debuggers. + +@c APPLE LOCAL begin prune man page +(Other debug formats, such as @option{-gcoff}, are not supported in +Darwin or Mac OS X.) +@ignore +@item -gvms +@opindex gvms +Produce debugging information in VMS debug format (if that is +supported). This is the format used by DEBUG on VMS systems. +@end ignore +@c APPLE LOCAL end prune man page + +@item -g@var{level} +@itemx -ggdb@var{level} +@itemx -gstabs@var{level} +@c APPLE LOCAL prune man page +@ignore +@itemx -gcoff@var{level} +@itemx -gxcoff@var{level} +@itemx -gvms@var{level} +@c APPLE LOCAL prune man page +@end ignore +Request debugging information and also use @var{level} to specify how +much information. The default level is 2. + +@c APPLE LOCAL begin mainline 4.3 2006-12-20 4869554 +Level 0 produces no debug information at all. Thus, @option{-g0} negates +@option{-g}. +@c APPLE LOCAL end mainline 4.3 2006-12-20 4869554 + +Level 1 produces minimal information, enough for making backtraces in +parts of the program that you don't plan to debug. This includes +descriptions of functions and external variables, but no information +about local variables and no line numbers. + +Level 3 includes extra information, such as all the macro definitions +present in the program. Some debuggers support macro expansion when +you use @option{-g3}. + +@option{-gdwarf-2} does not accept a concatenated debug level, because +GCC used to support an option @option{-gdwarf} that meant to generate +debug information in version 1 of the DWARF format (which is very +different from version 2), and it would have been too confusing. That +debug format is long obsolete, but the option cannot be changed now. +Instead use an additional @option{-g@var{level}} option to change the +debug level for DWARF2. + +@item -feliminate-dwarf2-dups +@opindex feliminate-dwarf2-dups +Compress DWARF2 debugging information by eliminating duplicated +information about each symbol. This option only makes sense when +generating DWARF2 debugging information with @option{-gdwarf-2}. + +@cindex @command{prof} +@item -p +@opindex p +Generate extra code to write profile information suitable for the +analysis program @command{prof}. You must use this option when compiling +the source files you want data about, and you must also use it when +linking. + +@cindex @command{gprof} +@item -pg +@opindex pg +Generate extra code to write profile information suitable for the +analysis program @command{gprof}. You must use this option when compiling +the source files you want data about, and you must also use it when +linking. + +@item -Q +@opindex Q +Makes the compiler print out each function name as it is compiled, and +print some statistics about each pass when it finishes. + +@item -ftime-report +@opindex ftime-report +Makes the compiler print some statistics about the time consumed by each +pass when it finishes. + +@item -fmem-report +@opindex fmem-report +Makes the compiler print some statistics about permanent memory +allocation when it finishes. + +@c APPLE LOCAL begin opt diary +@item -fopt-diary +@opindex fopt-diary +Enable optimization diary entries using DWARF encoding. This option +does nothing unless @option{gdwarf-2} is specified. +@c APPLE LOCAL end opt diary +@item -fprofile-arcs +@opindex fprofile-arcs +Add code so that program flow @dfn{arcs} are instrumented. During +execution the program records how many times each branch and call is +executed and how many times it is taken or returns. When the compiled +program exits it saves this data to a file called +@file{@var{auxname}.gcda} for each source file. The data may be used for +profile-directed optimizations (@option{-fbranch-probabilities}), or for +test coverage analysis (@option{-ftest-coverage}). Each object file's +@var{auxname} is generated from the name of the output file, if +explicitly specified and it is not the final executable, otherwise it is +the basename of the source file. In both cases any suffix is removed +(e.g.@: @file{foo.gcda} for input file @file{dir/foo.c}, or +@file{dir/foo.gcda} for output file specified as @option{-o dir/foo.o}). +@xref{Cross-profiling}. + +@cindex @command{gcov} +@item --coverage +@opindex coverage + +This option is used to compile and link code instrumented for coverage +analysis. The option is a synonym for @option{-fprofile-arcs} +@option{-ftest-coverage} (when compiling) and @option{-lgcov} (when +linking). See the documentation for those options for more details. + +@itemize + +@item +Compile the source files with @option{-fprofile-arcs} plus optimization +and code generation options. For test coverage analysis, use the +additional @option{-ftest-coverage} option. You do not need to profile +every source file in a program. + +@item +Link your object files with @option{-lgcov} or @option{-fprofile-arcs} +(the latter implies the former). + +@item +Run the program on a representative workload to generate the arc profile +information. This may be repeated any number of times. You can run +concurrent instances of your program, and provided that the file system +supports locking, the data files will be correctly updated. Also +@code{fork} calls are detected and correctly handled (double counting +will not happen). + +@item +For profile-directed optimizations, compile the source files again with +the same optimization and code generation options plus +@option{-fbranch-probabilities} (@pxref{Optimize Options,,Options that +Control Optimization}). + +@item +For test coverage analysis, use @command{gcov} to produce human readable +information from the @file{.gcno} and @file{.gcda} files. Refer to the +@command{gcov} documentation for further information. + +@end itemize + +With @option{-fprofile-arcs}, for each function of your program GCC +creates a program flow graph, then finds a spanning tree for the graph. +Only arcs that are not on the spanning tree have to be instrumented: the +compiler adds code to count the number of times that these arcs are +executed. When an arc is the only exit or only entrance to a block, the +instrumentation code can be added to the block; otherwise, a new basic +block must be created to hold the instrumentation code. + +@need 2000 +@item -ftest-coverage +@opindex ftest-coverage +Produce a notes file that the @command{gcov} code-coverage utility +(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}) can use to +show program coverage. Each source file's note file is called +@file{@var{auxname}.gcno}. Refer to the @option{-fprofile-arcs} option +above for a description of @var{auxname} and instructions on how to +generate test coverage data. Coverage data will match the source files +more closely, if you do not optimize. + +@c APPLE LOCAL begin mainline +@item -d@var{letters} +@item -fdump-rtl-@var{pass} +@opindex d +Says to make debugging dumps during compilation at times specified by +@var{letters}. This is used for debugging the RTL-based passes of the +compiler. The file names for most of the dumps are made by appending a +pass number and a word to the @var{dumpname}. @var{dumpname} is generated +from the name of the output file, if explicitly specified and it is not +an executable, otherwise it is the basename of the source file. These +switches may have different effects when @option{-E} is used for +preprocessing. +@c APPLE LOCAL end mainline + +Most debug dumps can be enabled either passing a letter to the @option{-d} +option, or with a long @option{-fdump-rtl} switch; here are the possible +letters for use in @var{letters} and @var{pass}, and their meanings: + +@table @gcctabopt +@item -dA +@opindex dA +Annotate the assembler output with miscellaneous debugging information. + +@item -dB +@itemx -fdump-rtl-bbro +@opindex dB +@opindex fdump-rtl-bbro +Dump after block reordering, to @file{@var{file}.148r.bbro}. + +@item -dc +@itemx -fdump-rtl-combine +@opindex dc +@opindex fdump-rtl-combine +Dump after instruction combination, to the file @file{@var{file}.129r.combine}. + +@item -dC +@itemx -fdump-rtl-ce1 +@itemx -fdump-rtl-ce2 +@opindex dC +@opindex fdump-rtl-ce1 +@opindex fdump-rtl-ce2 +@option{-dC} and @option{-fdump-rtl-ce1} enable dumping after the +first if conversion, to the file @file{@var{file}.117r.ce1}. @option{-dC} +and @option{-fdump-rtl-ce2} enable dumping after the second if +conversion, to the file @file{@var{file}.130r.ce2}. + +@item -dd +@itemx -fdump-rtl-btl +@itemx -fdump-rtl-dbr +@opindex dd +@opindex fdump-rtl-btl +@opindex fdump-rtl-dbr +@option{-dd} and @option{-fdump-rtl-btl} enable dumping after branch +target load optimization, to @file{@var{file}.31.btl}. @option{-dd} +and @option{-fdump-rtl-dbr} enable dumping after delayed branch +scheduling, to @file{@var{file}.36.dbr}. + +@item -dD +@opindex dD +Dump all macro definitions, at the end of preprocessing, in addition to +normal output. + +@item -dE +@itemx -fdump-rtl-ce3 +@opindex dE +@opindex fdump-rtl-ce3 +Dump after the third if conversion, to @file{@var{file}.146r.ce3}. + +@item -df +@itemx -fdump-rtl-cfg +@itemx -fdump-rtl-life +@opindex df +@opindex fdump-rtl-cfg +@opindex fdump-rtl-life +@option{-df} and @option{-fdump-rtl-cfg} enable dumping after control +and data flow analysis, to @file{@var{file}.116r.cfg}. @option{-df} +and @option{-fdump-rtl-cfg} enable dumping dump after life analysis, +to @file{@var{file}.128r.life1} and @file{@var{file}.135r.life2}. + +@item -dg +@itemx -fdump-rtl-greg +@opindex dg +@opindex fdump-rtl-greg +Dump after global register allocation, to @file{@var{file}.139r.greg}. + +@item -dG +@itemx -fdump-rtl-gcse +@itemx -fdump-rtl-bypass +@opindex dG +@opindex fdump-rtl-gcse +@opindex fdump-rtl-bypass +@option{-dG} and @option{-fdump-rtl-gcse} enable dumping after GCSE, to +@file{@var{file}.114r.gcse}. @option{-dG} and @option{-fdump-rtl-bypass} +enable dumping after jump bypassing and control flow optimizations, to +@file{@var{file}.115r.bypass}. + +@item -dh +@itemx -fdump-rtl-eh +@opindex dh +@opindex fdump-rtl-eh +Dump after finalization of EH handling code, to @file{@var{file}.02.eh}. + +@item -di +@itemx -fdump-rtl-sibling +@opindex di +@opindex fdump-rtl-sibling +Dump after sibling call optimizations, to @file{@var{file}.106r.sibling}. + +@item -dj +@itemx -fdump-rtl-jump +@opindex dj +@opindex fdump-rtl-jump +Dump after the first jump optimization, to @file{@var{file}.112r.jump}. + +@item -dk +@itemx -fdump-rtl-stack +@opindex dk +@opindex fdump-rtl-stack +Dump after conversion from registers to stack, to @file{@var{file}.152r.stack}. + +@item -dl +@itemx -fdump-rtl-lreg +@opindex dl +@opindex fdump-rtl-lreg +Dump after local register allocation, to @file{@var{file}.138r.lreg}. + +@item -dL +@itemx -fdump-rtl-loop2 +@opindex dL +@opindex fdump-rtl-loop2 +@option{-dL} and @option{-fdump-rtl-loop2} enable dumping after the +loop optimization pass, to @file{@var{file}.119r.loop2}, +@file{@var{file}.120r.loop2_init}, +@file{@var{file}.121r.loop2_invariant}, and +@file{@var{file}.125r.loop2_done}. + +@item -dm +@itemx -fdump-rtl-sms +@opindex dm +@opindex fdump-rtl-sms +Dump after modulo scheduling, to @file{@var{file}.136r.sms}. + +@item -dM +@itemx -fdump-rtl-mach +@opindex dM +@opindex fdump-rtl-mach +@c APPLE LOCAL begin mainline +Dump after performing the machine dependent reorganization pass, to +@file{@var{file}.155r.mach} if that pass exists. +@c APPLE LOCAL end mainline + +@item -dn +@itemx -fdump-rtl-rnreg +@opindex dn +@opindex fdump-rtl-rnreg +Dump after register renumbering, to @file{@var{file}.147r.rnreg}. + +@item -dN +@itemx -fdump-rtl-regmove +@opindex dN +@opindex fdump-rtl-regmove +Dump after the register move pass, to @file{@var{file}.132r.regmove}. + +@item -do +@itemx -fdump-rtl-postreload +@opindex do +@opindex fdump-rtl-postreload +Dump after post-reload optimizations, to @file{@var{file}.24.postreload}. + +@item -dr +@itemx -fdump-rtl-expand +@opindex dr +@opindex fdump-rtl-expand +Dump after RTL generation, to @file{@var{file}.104r.expand}. + +@item -dR +@itemx -fdump-rtl-sched2 +@opindex dR +@opindex fdump-rtl-sched2 +Dump after the second scheduling pass, to @file{@var{file}.150r.sched2}. + +@item -ds +@itemx -fdump-rtl-cse +@opindex ds +@opindex fdump-rtl-cse +Dump after CSE (including the jump optimization that sometimes follows +CSE), to @file{@var{file}.113r.cse}. + +@item -dS +@itemx -fdump-rtl-sched +@opindex dS +@opindex fdump-rtl-sched +Dump after the first scheduling pass, to @file{@var{file}.21.sched}. + +@item -dt +@itemx -fdump-rtl-cse2 +@opindex dt +@opindex fdump-rtl-cse2 +Dump after the second CSE pass (including the jump optimization that +sometimes follows CSE), to @file{@var{file}.127r.cse2}. + +@item -dT +@itemx -fdump-rtl-tracer +@opindex dT +@opindex fdump-rtl-tracer +Dump after running tracer, to @file{@var{file}.118r.tracer}. + +@item -dV +@itemx -fdump-rtl-vpt +@itemx -fdump-rtl-vartrack +@opindex dV +@opindex fdump-rtl-vpt +@opindex fdump-rtl-vartrack +@option{-dV} and @option{-fdump-rtl-vpt} enable dumping after the value +profile transformations, to @file{@var{file}.10.vpt}. @option{-dV} +and @option{-fdump-rtl-vartrack} enable dumping after variable tracking, +to @file{@var{file}.154r.vartrack}. + +@item -dw +@itemx -fdump-rtl-flow2 +@opindex dw +@opindex fdump-rtl-flow2 +Dump after the second flow pass, to @file{@var{file}.142r.flow2}. + +@item -dz +@itemx -fdump-rtl-peephole2 +@opindex dz +@opindex fdump-rtl-peephole2 +Dump after the peephole pass, to @file{@var{file}.145r.peephole2}. + +@item -dZ +@itemx -fdump-rtl-web +@opindex dZ +@opindex fdump-rtl-web +Dump after live range splitting, to @file{@var{file}.126r.web}. + +@item -da +@itemx -fdump-rtl-all +@opindex da +@opindex fdump-rtl-all +Produce all the dumps listed above. + +@item -dH +@opindex dH +Produce a core dump whenever an error occurs. + +@item -dm +@opindex dm +Print statistics on memory usage, at the end of the run, to +standard error. + +@item -dp +@opindex dp +Annotate the assembler output with a comment indicating which +pattern and alternative was used. The length of each instruction is +also printed. + +@item -dP +@opindex dP +Dump the RTL in the assembler output as a comment before each instruction. +Also turns on @option{-dp} annotation. + +@item -dv +@opindex dv +For each of the other indicated dump files (either with @option{-d} or +@option{-fdump-rtl-@var{pass}}), dump a representation of the control flow +graph suitable for viewing with VCG to @file{@var{file}.@var{pass}.vcg}. + +@item -dx +@opindex dx +Just generate RTL for a function instead of compiling it. Usually used +with @samp{r} (@option{-fdump-rtl-expand}). + +@item -dy +@opindex dy +Dump debugging information during parsing, to standard error. +@end table + +@item -fdump-noaddr +@opindex fdump-noaddr +When doing debugging dumps (see @option{-d} option above), suppress +address output. This makes it more feasible to use diff on debugging +dumps for compiler invocations with different compiler binaries and/or +different text / bss / data / heap / stack / dso start locations. + +@item -fdump-unnumbered +@opindex fdump-unnumbered +When doing debugging dumps (see @option{-d} option above), suppress instruction +numbers, line number note and address output. This makes it more feasible to +use diff on debugging dumps for compiler invocations with different +options, in particular with and without @option{-g}. + +@item -fdump-translation-unit @r{(C++ only)} +@itemx -fdump-translation-unit-@var{options} @r{(C++ only)} +@opindex fdump-translation-unit +Dump a representation of the tree structure for the entire translation +unit to a file. The file name is made by appending @file{.tu} to the +source file name. If the @samp{-@var{options}} form is used, @var{options} +controls the details of the dump as described for the +@option{-fdump-tree} options. + +@item -fdump-class-hierarchy @r{(C++ only)} +@itemx -fdump-class-hierarchy-@var{options} @r{(C++ only)} +@opindex fdump-class-hierarchy +Dump a representation of each class's hierarchy and virtual function +table layout to a file. The file name is made by appending @file{.class} +to the source file name. If the @samp{-@var{options}} form is used, +@var{options} controls the details of the dump as described for the +@option{-fdump-tree} options. + +@item -fdump-ipa-@var{switch} +@opindex fdump-ipa +Control the dumping at various stages of inter-procedural analysis +language tree to a file. The file name is generated by appending a switch +specific suffix to the source file name. The following dumps are possible: + +@table @samp +@item all +Enables all inter-procedural analysis dumps; currently the only produced +dump is the @samp{cgraph} dump. + +@item cgraph +Dumps information about call-graph optimization, unused function removal, +and inlining decisions. +@end table + +@item -fdump-tree-@var{switch} +@itemx -fdump-tree-@var{switch}-@var{options} +@opindex fdump-tree +Control the dumping at various stages of processing the intermediate +language tree to a file. The file name is generated by appending a switch +specific suffix to the source file name. If the @samp{-@var{options}} +form is used, @var{options} is a list of @samp{-} separated options that +control the details of the dump. Not all options are applicable to all +dumps, those which are not meaningful will be ignored. The following +options are available + +@table @samp +@item address +Print the address of each node. Usually this is not meaningful as it +changes according to the environment and source file. Its primary use +is for tying up a dump file with a debug environment. +@item slim +Inhibit dumping of members of a scope or body of a function merely +because that scope has been reached. Only dump such items when they +are directly reachable by some other path. When dumping pretty-printed +trees, this option inhibits dumping the bodies of control structures. +@item raw +Print a raw representation of the tree. By default, trees are +pretty-printed into a C-like representation. +@item details +Enable more detailed dumps (not honored by every dump option). +@item stats +Enable dumping various statistics about the pass (not honored by every dump +option). +@item blocks +Enable showing basic block boundaries (disabled in raw dumps). +@item vops +Enable showing virtual operands for every statement. +@item lineno +Enable showing line numbers for statements. +@item uid +Enable showing the unique ID (@code{DECL_UID}) for each variable. +@item all +Turn on all options, except @option{raw}, @option{slim} and @option{lineno}. +@end table + +The following tree dumps are possible: +@table @samp + +@item original +Dump before any tree based optimization, to @file{@var{file}.original}. + +@item optimized +Dump after all tree based optimization, to @file{@var{file}.optimized}. + +@item inlined +Dump after function inlining, to @file{@var{file}.inlined}. + +@item gimple +@opindex fdump-tree-gimple +Dump each function before and after the gimplification pass to a file. The +file name is made by appending @file{.gimple} to the source file name. + +@item cfg +@opindex fdump-tree-cfg +Dump the control flow graph of each function to a file. The file name is +made by appending @file{.cfg} to the source file name. + +@item vcg +@opindex fdump-tree-vcg +Dump the control flow graph of each function to a file in VCG format. The +file name is made by appending @file{.vcg} to the source file name. Note +that if the file contains more than one function, the generated file cannot +be used directly by VCG@. You will need to cut and paste each function's +graph into its own separate file first. + +@item ch +@opindex fdump-tree-ch +Dump each function after copying loop headers. The file name is made by +appending @file{.ch} to the source file name. + +@item ssa +@opindex fdump-tree-ssa +Dump SSA related information to a file. The file name is made by appending +@file{.ssa} to the source file name. + +@item salias +@opindex fdump-tree-salias +Dump structure aliasing variable information to a file. This file name +is made by appending @file{.salias} to the source file name. + +@item alias +@opindex fdump-tree-alias +Dump aliasing information for each function. The file name is made by +appending @file{.alias} to the source file name. + +@item ccp +@opindex fdump-tree-ccp +Dump each function after CCP@. The file name is made by appending +@file{.ccp} to the source file name. + +@item storeccp +@opindex fdump-tree-storeccp +Dump each function after STORE-CCP. The file name is made by appending +@file{.storeccp} to the source file name. + +@item pre +@opindex fdump-tree-pre +Dump trees after partial redundancy elimination. The file name is made +by appending @file{.pre} to the source file name. + +@item fre +@opindex fdump-tree-fre +Dump trees after full redundancy elimination. The file name is made +by appending @file{.fre} to the source file name. + +@item copyprop +@opindex fdump-tree-copyprop +Dump trees after copy propagation. The file name is made +by appending @file{.copyprop} to the source file name. + +@item store_copyprop +@opindex fdump-tree-store_copyprop +Dump trees after store copy-propagation. The file name is made +by appending @file{.store_copyprop} to the source file name. + +@item dce +@opindex fdump-tree-dce +Dump each function after dead code elimination. The file name is made by +appending @file{.dce} to the source file name. + +@item mudflap +@opindex fdump-tree-mudflap +Dump each function after adding mudflap instrumentation. The file name is +made by appending @file{.mudflap} to the source file name. + +@item sra +@opindex fdump-tree-sra +Dump each function after performing scalar replacement of aggregates. The +file name is made by appending @file{.sra} to the source file name. + +@item sink +@opindex fdump-tree-sink +Dump each function after performing code sinking. The file name is made +by appending @file{.sink} to the source file name. + +@item dom +@opindex fdump-tree-dom +Dump each function after applying dominator tree optimizations. The file +name is made by appending @file{.dom} to the source file name. + +@item dse +@opindex fdump-tree-dse +Dump each function after applying dead store elimination. The file +name is made by appending @file{.dse} to the source file name. + +@item phiopt +@opindex fdump-tree-phiopt +Dump each function after optimizing PHI nodes into straightline code. The file +name is made by appending @file{.phiopt} to the source file name. + +@item forwprop +@opindex fdump-tree-forwprop +Dump each function after forward propagating single use variables. The file +name is made by appending @file{.forwprop} to the source file name. + +@item copyrename +@opindex fdump-tree-copyrename +Dump each function after applying the copy rename optimization. The file +name is made by appending @file{.copyrename} to the source file name. + +@item nrv +@opindex fdump-tree-nrv +Dump each function after applying the named return value optimization on +generic trees. The file name is made by appending @file{.nrv} to the source +file name. + +@item vect +@opindex fdump-tree-vect +Dump each function after applying vectorization of loops. The file name is +made by appending @file{.vect} to the source file name. + +@item vrp +@opindex fdump-tree-vrp +Dump each function after Value Range Propagation (VRP). The file name +is made by appending @file{.vrp} to the source file name. + +@item all +@opindex fdump-tree-all +Enable all the available tree dumps with the flags provided in this option. +@end table + +@item -ftree-vectorizer-verbose=@var{n} +@opindex ftree-vectorizer-verbose +This option controls the amount of debugging output the vectorizer prints. +This information is written to standard error, unless +@option{-fdump-tree-all} or @option{-fdump-tree-vect} is specified, +in which case it is output to the usual dump listing file, @file{.vect}. +For @var{n}=0 no diagnostic information is reported. +If @var{n}=1 the vectorizer reports each loop that got vectorized, +and the total number of loops that got vectorized. +If @var{n}=2 the vectorizer also reports non-vectorized loops that passed +the first analysis phase (vect_analyze_loop_form) - i.e. countable, +inner-most, single-bb, single-entry/exit loops. This is the same verbosity +level that @option{-fdump-tree-vect-stats} uses. +Higher verbosity levels mean either more information dumped for each +reported loop, or same amount of information reported for more loops: +If @var{n}=3, alignment related information is added to the reports. +If @var{n}=4, data-references related information (e.g. memory dependences, +memory access-patterns) is added to the reports. +If @var{n}=5, the vectorizer reports also non-vectorized inner-most loops +that did not pass the first analysis phase (i.e. may not be countable, or +may have complicated control-flow). +If @var{n}=6, the vectorizer reports also non-vectorized nested loops. +For @var{n}=7, all the information the vectorizer generates during its +analysis and transformation is reported. This is the same verbosity level +that @option{-fdump-tree-vect-details} uses. + +@item -frandom-seed=@var{string} +@opindex frandom-string +This option provides a seed that GCC uses when it would otherwise use +random numbers. It is used to generate certain symbol names +that have to be different in every compiled file. It is also used to +place unique stamps in coverage data files and the object files that +produce them. You can use the @option{-frandom-seed} option to produce +reproducibly identical object files. + +The @var{string} should be different for every file you compile. + +@item -fsched-verbose=@var{n} +@opindex fsched-verbose +On targets that use instruction scheduling, this option controls the +amount of debugging output the scheduler prints. This information is +written to standard error, unless @option{-dS} or @option{-dR} is +specified, in which case it is output to the usual dump +listing file, @file{.sched} or @file{.sched2} respectively. However +for @var{n} greater than nine, the output is always printed to standard +error. + +For @var{n} greater than zero, @option{-fsched-verbose} outputs the +same information as @option{-dRS}. For @var{n} greater than one, it +also output basic block probabilities, detailed ready list information +and unit/insn info. For @var{n} greater than two, it includes RTL +at abort point, control-flow and regions info. And for @var{n} over +four, @option{-fsched-verbose} also includes dependence info. + +@item -save-temps +@opindex save-temps +Store the usual ``temporary'' intermediate files permanently; place them +in the current directory and name them based on the source file. Thus, +compiling @file{foo.c} with @samp{-c -save-temps} would produce files +@file{foo.i} and @file{foo.s}, as well as @file{foo.o}. This creates a +preprocessed @file{foo.i} output file even though the compiler now +normally uses an integrated preprocessor. + +When used in combination with the @option{-x} command line option, +@option{-save-temps} is sensible enough to avoid over writing an +input source file with the same extension as an intermediate file. +The corresponding intermediate file may be obtained by renaming the +source file before using @option{-save-temps}. + +@item -time +@opindex time +Report the CPU time taken by each subprocess in the compilation +sequence. For C source files, this is the compiler proper and assembler +(plus the linker if linking is done). The output looks like this: + +@smallexample +# cc1 0.12 0.01 +# as 0.00 0.01 +@end smallexample + +The first number on each line is the ``user time'', that is time spent +executing the program itself. The second number is ``system time'', +time spent executing operating system routines on behalf of the program. +Both numbers are in seconds. + +@item -fvar-tracking +@opindex fvar-tracking +Run variable tracking pass. It computes where variables are stored at each +position in code. Better debugging information is then generated +(if the debugging information format supports this information). + +It is enabled by default when compiling with optimization (@option{-Os}, +@c APPLE LOCAL -Oz +@option{-O}, @option{-O2}, @option{-Oz} (APPLE ONLY), ...), debugging information (@option{-g}) and +the debug info format supports it. + +@item -print-file-name=@var{library} +@opindex print-file-name +Print the full absolute name of the library file @var{library} that +would be used when linking---and don't do anything else. With this +option, GCC does not compile or link anything; it just prints the +file name. + +@item -print-multi-directory +@opindex print-multi-directory +Print the directory name corresponding to the multilib selected by any +other switches present in the command line. This directory is supposed +to exist in @env{GCC_EXEC_PREFIX}. + +@item -print-multi-lib +@opindex print-multi-lib +Print the mapping from multilib directory names to compiler switches +that enable them. The directory name is separated from the switches by +@samp{;}, and each switch starts with an @samp{@@} instead of the +@samp{-}, without spaces between multiple switches. This is supposed to +ease shell-processing. + +@item -print-prog-name=@var{program} +@opindex print-prog-name +Like @option{-print-file-name}, but searches for a program such as @samp{cpp}. + +@item -print-libgcc-file-name +@opindex print-libgcc-file-name +Same as @option{-print-file-name=libgcc.a}. + +This is useful when you use @option{-nostdlib} or @option{-nodefaultlibs} +but you do want to link with @file{libgcc.a}. You can do + +@smallexample +gcc -nostdlib @var{files}@dots{} `gcc -print-libgcc-file-name` +@end smallexample + +@item -print-search-dirs +@opindex print-search-dirs +Print the name of the configured installation directory and a list of +program and library directories @command{gcc} will search---and don't do anything else. + +This is useful when @command{gcc} prints the error message +@samp{installation problem, cannot exec cpp0: No such file or directory}. +To resolve this you either need to put @file{cpp0} and the other compiler +components where @command{gcc} expects to find them, or you can set the environment +variable @env{GCC_EXEC_PREFIX} to the directory where you installed them. +Don't forget the trailing @samp{/}. +@xref{Environment Variables}. + +@item -dumpmachine +@opindex dumpmachine +Print the compiler's target machine (for example, +@samp{i686-pc-linux-gnu})---and don't do anything else. + +@item -dumpversion +@opindex dumpversion +Print the compiler version (for example, @samp{3.0})---and don't do +anything else. + +@item -dumpspecs +@opindex dumpspecs +Print the compiler's built-in specs---and don't do anything else. (This +is used when GCC itself is being built.) @xref{Spec Files}. + +@item -feliminate-unused-debug-types +@opindex feliminate-unused-debug-types +Normally, when producing DWARF2 output, GCC will emit debugging +information for all types declared in a compilation +unit, regardless of whether or not they are actually used +in that compilation unit. Sometimes this is useful, such as +if, in the debugger, you want to cast a value to a type that is +not actually used in your program (but is declared). More often, +however, this results in a significant amount of wasted space. +With this option, GCC will avoid producing debug symbol output +for types that are nowhere used in the source file being compiled. +@end table + +@node Optimize Options +@section Options That Control Optimization +@cindex optimize options +@cindex options, optimization + +These options control various sorts of optimizations. + +Without any optimization option, the compiler's goal is to reduce the +cost of compilation and to make debugging produce the expected +results. Statements are independent: if you stop the program with a +breakpoint between statements, you can then assign a new value to any +variable or change the program counter to any other statement in the +function and get exactly the results you would expect from the source +code. + +Turning on optimization flags makes the compiler attempt to improve +the performance and/or code size at the expense of compilation time +and possibly the ability to debug the program. + +The compiler performs optimization based on the knowledge it has of +the program. Optimization levels @option{-O} and above, in +particular, enable @emph{unit-at-a-time} mode, which allows the +compiler to consider information gained from later functions in +the file when compiling a function. Compiling multiple files at +once to a single output file in @emph{unit-at-a-time} mode allows +the compiler to use information gained from all of the files when +compiling each of them. + +Not all optimizations are controlled directly by a flag. Only +optimizations that have a flag are listed. + +@table @gcctabopt +@item -O +@itemx -O1 +@opindex O +@opindex O1 +Optimize. Optimizing compilation takes somewhat more time, and a lot +more memory for a large function. + +With @option{-O}, the compiler tries to reduce code size and execution +time, without performing any optimizations that take a great deal of +compilation time. + +@option{-O} turns on the following optimization flags: +@gccoptlist{-fdefer-pop @gol +-fdelayed-branch @gol +-fguess-branch-probability @gol +-fcprop-registers @gol +-fif-conversion @gol +-fif-conversion2 @gol +-ftree-ccp @gol +-ftree-dce @gol +-ftree-dominator-opts @gol +-ftree-dse @gol +-ftree-ter @gol +-ftree-lrs @gol +-ftree-sra @gol +-ftree-copyrename @gol +-ftree-fre @gol +-ftree-ch @gol +-funit-at-a-time @gol +-fmerge-constants} + +@option{-O} also turns on @option{-fomit-frame-pointer} on machines +where doing so does not interfere with debugging. + +@item -O2 +@opindex O2 +Optimize even more. GCC performs nearly all supported optimizations +that do not involve a space-speed tradeoff. The compiler does not +perform loop unrolling or function inlining when you specify @option{-O2}. +As compared to @option{-O}, this option increases both compilation time +and the performance of the generated code. + +@option{-O2} turns on all optimization flags specified by @option{-O}. It +also turns on the following optimization flags: +@gccoptlist{-fthread-jumps @gol +-fcrossjumping @gol +-foptimize-sibling-calls @gol +-fcse-follow-jumps -fcse-skip-blocks @gol +-fgcse -fgcse-lm @gol +-fexpensive-optimizations @gol +-frerun-cse-after-loop @gol +-fcaller-saves @gol +-fpeephole2 @gol +-fschedule-insns -fschedule-insns2 @gol +-fsched-interblock -fsched-spec @gol +-fregmove @gol +-fstrict-aliasing -fstrict-overflow @gol +-fdelete-null-pointer-checks @gol +-freorder-blocks -freorder-functions @gol +-falign-functions -falign-jumps @gol +-falign-loops -falign-labels @gol +-ftree-vrp @gol +-ftree-pre} + +Please note the warning under @option{-fgcse} about +invoking @option{-O2} on programs that use computed gotos. + +@option{-O2} doesn't turn on @option{-ftree-vrp} for the Ada compiler. +This option must be explicitly specified on the command line to be +enabled for the Ada compiler. + +@c APPLE LOCAL begin optimization +In Apple's version of GCC, @option{-fstrict-aliasing}, +@option{-freorder-blocks}, and @option{-fsched-interblock} +are disabled by default when optimizing. +@c APPLE LOCAL end optimization + +@item -O3 +@opindex O3 +Optimize yet more. @option{-O3} turns on all optimizations specified by +@option{-O2} and also turns on the @option{-finline-functions}, +@option{-funswitch-loops} and @option{-fgcse-after-reload} options. + +@item -O0 +@opindex O0 +Do not optimize. This is the default. + +@c APPLE LOCAL begin -fast or -fastf or -fastcp +@item -fast +@opindex fast +Optimize for maximum performance. @option{-fast} changes the overall optimization +strategy of GCC in order to produce the fastest possible running code for PPC7450 +and G5 architectures. By default, @option{-fast} optimizes for G5. Programs +optimized for G5 will not run on PPC7450. To optimize for PPC7450, add +@option{-mcpu=7450} on command line. + +@option{-fast} currently enables the following optimization flags (for G5 and PPC7450). +These flags may change in the future. You cannot override any of these options if you use +@option{-fast} except by setting @option{-mcpu=7450} (or @option{-fPIC}, see below). + +@gccoptlist{-O3 +-falign-loops-max-skip=15 +-falign-jumps-max-skip=15 +-falign-loops=16 +-falign-jumps=16 +-falign-functions=16 +-malign-natural (except when -fastf is specified) +-ffast-math +-fstrict-aliasing +-funroll-loops +-ftree-loop-linear +-ftree-loop-memset +-mcpu=G5 +-mpowerpc-gpopt +-mtune=G5 (unless -mtune=G4 is specified). +-fsched-interblock +-fgcse-sm +-mpowerpc64} + +To build shared libraries with @option{-fast}, specify @option{-fPIC} +on the command line as @option{-fast} turns on @option{-mdynamic-no-pic} +otherwise. + +Important notes: @option{-ffast-math} results in code that is not necessarily +IEEE-compliant. @option{-fstrict-aliasing} is highly likely to break +non-standard-compliant programs. @option{-malign-natural} only works properly if +the entire program is compiled with it, and none of the standard headers/libraries +contain any code that changes alignment when this option is used. + +On Intel target, @option{-fast} currently enables the following optimization flags: + +@gccoptlist{-O3 +-fomit-frame-pointer +-fstrict-aliasing +-momit-leaf-frame-pointer +-fno-tree-pre +-falign-loops} + +All choices of flags enabled by @option{-fast} are subject to change without notice. + +@c APPLE LOCAL end -fast or -fastf or -fastcp + +@c APPLE LOCAL begin 4231761 -Oz +@item -Os +@opindex Os +Optimize for size, but not at the expense of speed. +@option{-Os} enables all @option{-O2} optimizations that +do not typically increase code size. However, instructions +are chosen for best performance, regardless of size. +To optimize solely for size on Darwin, use @option{-Oz} (APPLE ONLY). + +The following options are set for @option{-O2}, but are disabled under @option{-Os}: +@gccoptlist{-falign-functions -falign-jumps -falign-loops @gol +-falign-labels -freorder-blocks -freorder-blocks-and-partition @gol +-fprefetch-loop-arrays -ftree-vect-loop-version} + +@c APPLE LOCAL begin 4200438 +When optimizing with @option{-Os} or @option{-Oz} (APPLE ONLY) on +Darwin, any function up to 30 ``estimated insns'' in size will be +considered for inlining. When compiling C and Objective-C sourcefiles with +@option{-Os} or @option{-Oz} on Darwin, functions explictly marked +with the @code{inline} keyword up to 450 ``estimated insns'' in size +will be considered for inlining. +@c APPLE LOCAL end 4200438 +@c APPLE LOCAL begin Disable string insns with -Os on Darwin (radar 3509006) +When compiling for Apple POWERPC targets, @option{-Os} and +@option{-Oz} (APPLE ONLY) disable use of the string instructions even though they +would usually be smaller, because the kernel can't emulate them +correctly in some rare cases. This behavior is not portable to any +other gcc environment, and will not affect most programs at all. If +you really want the string instructions, use -mstring. +@c APPLE LOCAL end Disable string insns with -Os on Darwin (radar 3509006) + +@item -Oz +@opindex Oz +(APPLE ONLY) Optimize for size, regardless of performance. +@option{-Oz} enables the same optimization flags that @option{-Os} +uses, but @option{-Oz} also enables other optimizations intended solely +to reduce code size. In particular, instructions that encode into +fewer bytes are preferred over longer instructions that execute in +fewer cycles. @option{-Oz} on Darwin is very similar to @option{-Os} +in FSF distributions of GCC. @option{-Oz} employs the same inlining +limits and avoids string instructions just like @option{-Os}. +@c APPLE LOCAL end 4231761 -Oz + +If you use multiple @option{-O} options, with or without level numbers, +the last such option is the one that is effective. +@end table + +Options of the form @option{-f@var{flag}} specify machine-independent +flags. Most flags have both positive and negative forms; the negative +form of @option{-ffoo} would be @option{-fno-foo}. In the table +below, only one of the forms is listed---the one you typically will +use. You can figure out the other form by either removing @samp{no-} +or adding it. + +The following options control specific optimizations. They are either +activated by @option{-O} options or are related to ones that are. You +can use the following flags in the rare cases when ``fine-tuning'' of +optimizations to be performed is desired. + +@table @gcctabopt +@item -fno-default-inline +@opindex fno-default-inline +Do not make member functions inline by default merely because they are +defined inside the class scope (C++ only). Otherwise, when you specify +@w{@option{-O}}, member functions defined inside class scope are compiled +inline by default; i.e., you don't need to add @samp{inline} in front of +the member function name. + +@item -fno-defer-pop +@opindex fno-defer-pop +Always pop the arguments to each function call as soon as that function +returns. For machines which must pop arguments after a function call, +the compiler normally lets arguments accumulate on the stack for several +function calls and pops them all at once. + +@c APPLE LOCAL begin 4231761 -Oz +Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, +@option{-Oz} (APPLE ONLY). +@c APPLE LOCAL end 4231761 -Oz + +@item -fforce-mem +@opindex fforce-mem +Force memory operands to be copied into registers before doing +arithmetic on them. This produces better code by making all memory +references potential common subexpressions. When they are not common +subexpressions, instruction combination should eliminate the separate +register-load. This option is now a nop and will be removed in 4.3. + +@item -fforce-addr +@opindex fforce-addr +Force memory address constants to be copied into registers before +doing arithmetic on them. + +@item -fomit-frame-pointer +@opindex fomit-frame-pointer +Don't keep the frame pointer in a register for functions that +don't need one. This avoids the instructions to save, set up and +restore frame pointers; it also makes an extra register available +in many functions. @strong{It also makes debugging impossible on +some machines.} + +On some machines, such as the VAX, this flag has no effect, because +the standard calling sequence automatically handles the frame pointer +and nothing is saved by pretending it doesn't exist. The +machine-description macro @code{FRAME_POINTER_REQUIRED} controls +whether a target machine supports this flag. @xref{Registers,,Register +Usage, gccint, GNU Compiler Collection (GCC) Internals}. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -foptimize-sibling-calls +@opindex foptimize-sibling-calls +Optimize sibling and tail recursive calls. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fno-inline +@opindex fno-inline +Don't pay attention to the @code{inline} keyword. Normally this option +is used to keep the compiler from expanding any functions inline. +Note that if you are not optimizing, no functions can be expanded inline. + +@item -finline-functions +@opindex finline-functions +Integrate all simple functions into their callers. The compiler +heuristically decides which functions are simple enough to be worth +integrating in this way. + +If all calls to a given function are integrated, and the function is +declared @code{static}, then the function is normally not output as +assembler code in its own right. + +Enabled at level @option{-O3}. + +@item -finline-functions-called-once +@opindex finline-functions-called-once +Consider all @code{static} functions called once for inlining into their +caller even if they are not marked @code{inline}. If a call to a given +function is integrated, then the function is not output as assembler code +in its own right. + +Enabled if @option{-funit-at-a-time} is enabled. + +@item -fearly-inlining +@opindex fearly-inlining +Inline functions marked by @code{always_inline} and functions whose body seems +smaller than the function call overhead early before doing +@option{-fprofile-generate} instrumentation and real inlining pass. Doing so +makes profiling significantly cheaper and usually inlining faster on programs +having large chains of nested wrapper functions. + +Enabled by default. + +@item -finline-limit=@var{n} +@opindex finline-limit +By default, GCC limits the size of functions that can be inlined. This flag +allows the control of this limit for functions that are explicitly marked as +inline (i.e., marked with the inline keyword or defined within the class +definition in c++). @var{n} is the size of functions that can be inlined in +number of pseudo instructions (not counting parameter handling). The default +value of @var{n} is 600. +Increasing this value can result in more inlined code at +the cost of compilation time and memory consumption. Decreasing usually makes +the compilation faster and less code will be inlined (which presumably +means slower programs). This option is particularly useful for programs that +use inlining heavily such as those based on recursive templates with C++. + +Inlining is actually controlled by a number of parameters, which may be +specified individually by using @option{--param @var{name}=@var{value}}. +The @option{-finline-limit=@var{n}} option sets some of these parameters +as follows: + +@table @gcctabopt +@item max-inline-insns-single + is set to @var{n}/2. +@item max-inline-insns-auto + is set to @var{n}/2. +@item min-inline-insns + is set to 130 or @var{n}/4, whichever is smaller. +@item max-inline-insns-rtl + is set to @var{n}. +@end table + +See below for a documentation of the individual +parameters controlling inlining. + +@emph{Note:} pseudo instruction represents, in this particular context, an +abstract measurement of function's size. In no way does it represent a count +of assembly instructions and as such its exact meaning might change from one +release to an another. + +@item -fkeep-inline-functions +@opindex fkeep-inline-functions +In C, emit @code{static} functions that are declared @code{inline} +into the object file, even if the function has been inlined into all +of its callers. This switch does not affect functions using the +@code{extern inline} extension in GNU C@. In C++, emit any and all +inline functions into the object file. + +@item -fkeep-static-consts +@opindex fkeep-static-consts +Emit variables declared @code{static const} when optimization isn't turned +on, even if the variables aren't referenced. + +GCC enables this option by default. If you want to force the compiler to +check if the variable was referenced, regardless of whether or not +optimization is turned on, use the @option{-fno-keep-static-consts} option. + +@c APPLE LOCAL begin ARM conditionally disable local RA +@item -flocal-alloc +(APPLE ONLY) Enable the local (intra-basic-block) register allocator. + +GCC enables this option by default. If you want to force the compiler to +supress register allocation within a basic block, use the +@option{-fno-local-alloc} option. This option cannot be disabled with +@option{-O0}, for correctness reasons. +@c APPLE LOCAL end ARM conditionally disable local RA + +@item -fmerge-constants +Attempt to merge identical constants (string constants and floating point +constants) across compilation units. + +This option is the default for optimized compilation if the assembler and +linker support it. Use @option{-fno-merge-constants} to inhibit this +behavior. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fmerge-all-constants +Attempt to merge identical constants and identical variables. + +This option implies @option{-fmerge-constants}. In addition to +@option{-fmerge-constants} this considers e.g.@: even constant initialized +arrays or initialized constant variables with integral or floating point +types. Languages like C or C++ require each non-automatic variable to +have distinct location, so using this option will result in non-conforming +behavior. + +@item -fmodulo-sched +@opindex fmodulo-sched +Perform swing modulo scheduling immediately before the first scheduling +pass. This pass looks at innermost loops and reorders their +instructions by overlapping different iterations. + +@item -fno-branch-count-reg +@opindex fno-branch-count-reg +Do not use ``decrement and branch'' instructions on a count register, +but instead generate a sequence of instructions that decrement a +register, compare it against zero, then branch based upon the result. +This option is only meaningful on architectures that support such +instructions, which include x86, PowerPC, IA-64 and S/390. + +The default is @option{-fbranch-count-reg}. + +@item -fno-function-cse +@opindex fno-function-cse +Do not put function addresses in registers; make each instruction that +calls a constant function contain the function's address explicitly. + +This option results in less efficient code, but some strange hacks +that alter the assembler output may be confused by the optimizations +performed when this option is not used. + +The default is @option{-ffunction-cse} + +@item -fno-zero-initialized-in-bss +@opindex fno-zero-initialized-in-bss +If the target supports a BSS section, GCC by default puts variables that +are initialized to zero into BSS@. This can save space in the resulting +code. + +This option turns off this behavior because some programs explicitly +rely on variables going to the data section. E.g., so that the +resulting executable can find the beginning of that section and/or make +assumptions based on that. + +The default is @option{-fzero-initialized-in-bss}. + +@item -fbounds-check +@opindex fbounds-check +For front-ends that support it, generate additional code to check that +indices used to access arrays are within the declared range. This is +currently only supported by the Java and Fortran front-ends, where +this option defaults to true and false respectively. + +@item -fmudflap -fmudflapth -fmudflapir +@opindex fmudflap +@opindex fmudflapth +@opindex fmudflapir +@cindex bounds checking +@cindex mudflap +For front-ends that support it (C and C++), instrument all risky +pointer/array dereferencing operations, some standard library +string/heap functions, and some other associated constructs with +range/validity tests. Modules so instrumented should be immune to +buffer overflows, invalid heap use, and some other classes of C/C++ +programming errors. The instrumentation relies on a separate runtime +library (@file{libmudflap}), which will be linked into a program if +@option{-fmudflap} is given at link time. Run-time behavior of the +instrumented program is controlled by the @env{MUDFLAP_OPTIONS} +environment variable. See @code{env MUDFLAP_OPTIONS=-help a.out} +for its options. + +Use @option{-fmudflapth} instead of @option{-fmudflap} to compile and to +link if your program is multi-threaded. Use @option{-fmudflapir}, in +addition to @option{-fmudflap} or @option{-fmudflapth}, if +instrumentation should ignore pointer reads. This produces less +instrumentation (and therefore faster execution) and still provides +some protection against outright memory corrupting writes, but allows +erroneously read data to propagate within a program. + +@item -fthread-jumps +@opindex fthread-jumps +Perform optimizations where we check to see if a jump branches to a +location where another comparison subsumed by the first is found. If +so, the first branch is redirected to either the destination of the +second branch or a point immediately following it, depending on whether +the condition is known to be true or false. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fcse-follow-jumps +@opindex fcse-follow-jumps +In common subexpression elimination, scan through jump instructions +when the target of the jump is not reached by any other path. For +example, when CSE encounters an @code{if} statement with an +@code{else} clause, CSE will follow the jump when the condition +tested is false. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fcse-skip-blocks +@opindex fcse-skip-blocks +This is similar to @option{-fcse-follow-jumps}, but causes CSE to +follow jumps which conditionally skip over blocks. When CSE +encounters a simple @code{if} statement with no else clause, +@option{-fcse-skip-blocks} causes CSE to follow the jump around the +body of the @code{if}. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -frerun-cse-after-loop +@opindex frerun-cse-after-loop +Re-run common subexpression elimination after loop optimizations has been +performed. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fgcse +@opindex fgcse +Perform a global common subexpression elimination pass. +This pass also performs global constant and copy propagation. + +@emph{Note:} When compiling a program using computed gotos, a GCC +extension, you may get better runtime performance if you disable +the global common subexpression elimination pass by adding +@option{-fno-gcse} to the command line. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fgcse-lm +@opindex fgcse-lm +When @option{-fgcse-lm} is enabled, global common subexpression elimination will +attempt to move loads which are only killed by stores into themselves. This +allows a loop containing a load/store sequence to be changed to a load outside +the loop, and a copy/store within the loop. + +Enabled by default when gcse is enabled. + +@item -fgcse-sm +@opindex fgcse-sm +When @option{-fgcse-sm} is enabled, a store motion pass is run after +global common subexpression elimination. This pass will attempt to move +stores out of loops. When used in conjunction with @option{-fgcse-lm}, +loops containing a load/store sequence can be changed to a load before +the loop and a store after the loop. + +Not enabled at any optimization level. + +@item -fgcse-las +@opindex fgcse-las +When @option{-fgcse-las} is enabled, the global common subexpression +elimination pass eliminates redundant loads that come after stores to the +same memory location (both partial and full redundancies). + +Not enabled at any optimization level. + +@item -fgcse-after-reload +@opindex fgcse-after-reload +When @option{-fgcse-after-reload} is enabled, a redundant load elimination +pass is performed after reload. The purpose of this pass is to cleanup +redundant spilling. + +@item -funsafe-loop-optimizations +@opindex funsafe-loop-optimizations +If given, the loop optimizer will assume that loop indices do not +overflow, and that the loops with nontrivial exit condition are not +infinite. This enables a wider range of loop optimizations even if +the loop optimizer itself cannot prove that these assumptions are valid. +Using @option{-Wunsafe-loop-optimizations}, the compiler will warn you +if it finds this kind of loop. + +@item -fcrossjumping +@opindex crossjumping +Perform cross-jumping transformation. This transformation unifies equivalent code and save code size. The +resulting code may or may not perform better than without cross-jumping. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fif-conversion +@opindex if-conversion +Attempt to transform conditional jumps into branch-less equivalents. This +include use of conditional moves, min, max, set flags and abs instructions, and +some tricks doable by standard arithmetics. The use of conditional execution +on chips where it is available is controlled by @code{if-conversion2}. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fif-conversion2 +@opindex if-conversion2 +Use conditional execution (where available) to transform conditional jumps into +branch-less equivalents. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fdelete-null-pointer-checks +@opindex fdelete-null-pointer-checks +Use global dataflow analysis to identify and eliminate useless checks +for null pointers. The compiler assumes that dereferencing a null +pointer would have halted the program. If a pointer is checked after +it has already been dereferenced, it cannot be null. + +In some environments, this assumption is not true, and programs can +safely dereference null pointers. Use +@option{-fno-delete-null-pointer-checks} to disable this optimization +for programs which depend on that behavior. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fexpensive-optimizations +@opindex fexpensive-optimizations +Perform a number of minor optimizations that are relatively expensive. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -foptimize-register-move +@itemx -fregmove +@opindex foptimize-register-move +@opindex fregmove +Attempt to reassign register numbers in move instructions and as +operands of other simple instructions in order to maximize the amount of +register tying. This is especially helpful on machines with two-operand +instructions. + +Note @option{-fregmove} and @option{-foptimize-register-move} are the same +optimization. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fdelayed-branch +@opindex fdelayed-branch +If supported for the target machine, attempt to reorder instructions +to exploit instruction slots available after delayed branch +instructions. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fschedule-insns +@opindex fschedule-insns +If supported for the target machine, attempt to reorder instructions to +eliminate execution stalls due to required data being unavailable. This +helps machines that have slow floating point or memory load instructions +by allowing other instructions to be issued until the result of the load +or floating point instruction is required. + +@c APPLE LOCAL begin 4231761 5591571 +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} for PPC targets; +ignored for x86 targets (APPLE ONLY). +@c APPLE LOCAL end 4231761 5591571 + +@item -fschedule-insns2 +@opindex fschedule-insns2 +Similar to @option{-fschedule-insns}, but requests an additional pass of +instruction scheduling after register allocation has been done. This is +especially useful on machines with a relatively small number of +registers and where memory load instructions take more than one cycle. + +@c APPLE LOCAL begin 4231761 5591571 +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} for PPC targets; +ignored for x86 targets (APPLE ONLY). +@c APPLE LOCAL end 4231761 5591571 + +@item -fno-sched-interblock +@opindex fno-sched-interblock +Don't schedule instructions across basic blocks. This is normally +enabled by default when scheduling before register allocation, i.e.@: +with @option{-fschedule-insns} or at @option{-O2} or higher. + +@item -fno-sched-spec +@opindex fno-sched-spec +Don't allow speculative motion of non-load instructions. This is normally +enabled by default when scheduling before register allocation, i.e.@: +with @option{-fschedule-insns} or at @option{-O2} or higher. + +@item -fsched-spec-load +@opindex fsched-spec-load +Allow speculative motion of some load instructions. This only makes +sense when scheduling before register allocation, i.e.@: with +@option{-fschedule-insns} or at @option{-O2} or higher. + +@item -fsched-spec-load-dangerous +@opindex fsched-spec-load-dangerous +Allow speculative motion of more load instructions. This only makes +sense when scheduling before register allocation, i.e.@: with +@option{-fschedule-insns} or at @option{-O2} or higher. + +@item -fsched-stalled-insns=@var{n} +@opindex fsched-stalled-insns +Define how many insns (if any) can be moved prematurely from the queue +of stalled insns into the ready list, during the second scheduling pass. + +@item -fsched-stalled-insns-dep=@var{n} +@opindex fsched-stalled-insns-dep +Define how many insn groups (cycles) will be examined for a dependency +on a stalled insn that is candidate for premature removal from the queue +of stalled insns. Has an effect only during the second scheduling pass, +and only if @option{-fsched-stalled-insns} is used and its value is not zero. + +@item -fsched2-use-superblocks +@opindex fsched2-use-superblocks +When scheduling after register allocation, do use superblock scheduling +algorithm. Superblock scheduling allows motion across basic block boundaries +resulting on faster schedules. This option is experimental, as not all machine +descriptions used by GCC model the CPU closely enough to avoid unreliable +results from the algorithm. + +This only makes sense when scheduling after register allocation, i.e.@: with +@option{-fschedule-insns2} or at @option{-O2} or higher. + +@item -fsched2-use-traces +@opindex fsched2-use-traces +Use @option{-fsched2-use-superblocks} algorithm when scheduling after register +allocation and additionally perform code duplication in order to increase the +size of superblocks using tracer pass. See @option{-ftracer} for details on +trace formation. + +This mode should produce faster but significantly longer programs. Also +without @option{-fbranch-probabilities} the traces constructed may not +match the reality and hurt the performance. This only makes +sense when scheduling after register allocation, i.e.@: with +@option{-fschedule-insns2} or at @option{-O2} or higher. + +@item -fsee +@opindex fsee +Eliminates redundant extension instructions and move the non redundant +ones to optimal placement using LCM. + +@item -freschedule-modulo-scheduled-loops +@opindex fscheduling-in-modulo-scheduled-loops +The modulo scheduling comes before the traditional scheduling, if a loop was modulo scheduled +we may want to prevent the later scheduling passes from changing its schedule, we use this +option to control that. + +@item -fcaller-saves +@opindex fcaller-saves +Enable values to be allocated in registers that will be clobbered by +function calls, by emitting extra instructions to save and restore the +registers around such calls. Such allocation is done only when it +seems to result in better code than would otherwise be produced. + +This option is always enabled by default on certain machines, usually +those which have no call-preserved registers to use instead. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -ftree-pre +Perform Partial Redundancy Elimination (PRE) on trees. This flag is +enabled by default at @option{-O2} and @option{-O3}. + +@item -ftree-fre +Perform Full Redundancy Elimination (FRE) on trees. The difference +between FRE and PRE is that FRE only considers expressions +that are computed on all paths leading to the redundant computation. +This analysis faster than PRE, though it exposes fewer redundancies. +This flag is enabled by default at @option{-O} and higher. + +@item -ftree-copy-prop +Perform copy propagation on trees. This pass eliminates unnecessary +copy operations. This flag is enabled by default at @option{-O} and +higher. + +@item -ftree-store-copy-prop +Perform copy propagation of memory loads and stores. This pass +eliminates unnecessary copy operations in memory references +(structures, global variables, arrays, etc). This flag is enabled by +default at @option{-O2} and higher. + +@item -ftree-salias +Perform structural alias analysis on trees. This flag +is enabled by default at @option{-O} and higher. + +@item -fipa-pta +Perform interprocedural pointer analysis. + +@item -ftree-sink +Perform forward store motion on trees. This flag is +enabled by default at @option{-O} and higher. + +@item -ftree-ccp +Perform sparse conditional constant propagation (CCP) on trees. This +pass only operates on local scalar variables and is enabled by default +at @option{-O} and higher. + +@item -ftree-store-ccp +Perform sparse conditional constant propagation (CCP) on trees. This +pass operates on both local scalar variables and memory stores and +loads (global variables, structures, arrays, etc). This flag is +enabled by default at @option{-O2} and higher. + +@item -ftree-dce +Perform dead code elimination (DCE) on trees. This flag is enabled by +default at @option{-O} and higher. + +@item -ftree-dominator-opts +Perform a variety of simple scalar cleanups (constant/copy +propagation, redundancy elimination, range propagation and expression +simplification) based on a dominator tree traversal. This also +performs jump threading (to reduce jumps to jumps). This flag is +enabled by default at @option{-O} and higher. + +@item -ftree-ch +Perform loop header copying on trees. This is beneficial since it increases +effectiveness of code motion optimizations. It also saves one jump. This flag +is enabled by default at @option{-O} and higher. It is not enabled +@c APPLE LOCAL 4231761 -Oz +for @option{-Os} or @option{-Oz} (APPLE ONLY), since it usually increases code size. + +@item -ftree-loop-optimize +Perform loop optimizations on trees. This flag is enabled by default +at @option{-O} and higher. + +@item -ftree-loop-linear +Perform linear loop transformations on tree. This flag can improve cache +performance and allow further loop optimizations to take place. +@c APPLE LOCAL begin buggy opt 4420531 3950497 3984937 4013797 +This flag is known to have bugs that cause incorrect code to be generated in +some rare cases. Note this flag is included in -fast. +@c APPLE LOCAL end buggy opt 4420531 3950497 3984937 4013797 + +@item -ftree-loop-im +Perform loop invariant motion on trees. This pass moves only invariants that +would be hard to handle at RTL level (function calls, operations that expand to +nontrivial sequences of insns). With @option{-funswitch-loops} it also moves +operands of conditions that are invariant out of the loop, so that we can use +just trivial invariantness analysis in loop unswitching. The pass also includes +store motion. + +@item -ftree-loop-ivcanon +Create a canonical counter for number of iterations in the loop for that +determining number of iterations requires complicated analysis. Later +optimizations then may determine the number easily. Useful especially +in connection with unrolling. + +@item -fivopts +Perform induction variable optimizations (strength reduction, induction +variable merging and induction variable elimination) on trees. + +@item -ftree-sra +Perform scalar replacement of aggregates. This pass replaces structure +references with scalars to prevent committing structures to memory too +early. This flag is enabled by default at @option{-O} and higher. + +@item -ftree-copyrename +Perform copy renaming on trees. This pass attempts to rename compiler +temporaries to other variables at copy locations, usually resulting in +variable names which more closely resemble the original variables. This flag +is enabled by default at @option{-O} and higher. + +@item -ftree-ter +Perform temporary expression replacement during the SSA->normal phase. Single +use/single def temporaries are replaced at their use location with their +defining expression. This results in non-GIMPLE code, but gives the expanders +much more complex trees to work on resulting in better RTL generation. This is +enabled by default at @option{-O} and higher. + +@item -ftree-lrs +Perform live range splitting during the SSA->normal phase. Distinct live +ranges of a variable are split into unique variables, allowing for better +optimization later. This is enabled by default at @option{-O} and higher. + +@item -ftree-vectorize +Perform loop vectorization on trees. + +@c APPLE LOCAL begin optimization +In Apple's version of GCC, @option{-fstrict-aliasing} is enabled by default +when loop vectorization is enabled. See @option{-fstrict-aliasing} document +for more information. +@c APPLE LOCAL end optimization + +@item -ftree-vect-loop-version +@opindex ftree-vect-loop-version +Perform loop versioning when doing loop vectorization on trees. When a loop +appears to be vectorizable except that data alignment or data dependence cannot +be determined at compile time then vectorized and non-vectorized versions of +the loop are generated along with runtime checks for alignment or dependence +to control which version is executed. This option is enabled by default +except at level @option{-Os} where it is disabled. + +@item -ftree-vrp +Perform Value Range Propagation on trees. This is similar to the +constant propagation pass, but instead of values, ranges of values are +propagated. This allows the optimizers to remove unnecessary range +checks like array bound checks and null pointer checks. This is +enabled by default at @option{-O2} and higher. Null pointer check +elimination is only done if @option{-fdelete-null-pointer-checks} is +enabled. + +@item -ftracer +@opindex ftracer +Perform tail duplication to enlarge superblock size. This transformation +simplifies the control flow of the function allowing other optimizations to do +better job. + +@item -funroll-loops +@opindex funroll-loops +Unroll loops whose number of iterations can be determined at compile +time or upon entry to the loop. @option{-funroll-loops} implies +@option{-frerun-cse-after-loop}. This option makes code larger, +and may or may not make it run faster. + +@item -funroll-all-loops +@opindex funroll-all-loops +Unroll all loops, even if their number of iterations is uncertain when +the loop is entered. This usually makes programs run more slowly. +@option{-funroll-all-loops} implies the same options as +@option{-funroll-loops}, + +@item -fsplit-ivs-in-unroller +@opindex fsplit-ivs-in-unroller +Enables expressing of values of induction variables in later iterations +of the unrolled loop using the value in the first iteration. This breaks +long dependency chains, thus improving efficiency of the scheduling passes. + +Combination of @option{-fweb} and CSE is often sufficient to obtain the +same effect. However in cases the loop body is more complicated than +a single basic block, this is not reliable. It also does not work at all +on some of the architectures due to restrictions in the CSE pass. + +This optimization is enabled by default. + +@item -fvariable-expansion-in-unroller +@opindex fvariable-expansion-in-unroller +With this option, the compiler will create multiple copies of some +local variables when unrolling a loop which can result in superior code. + +@item -fprefetch-loop-arrays +@opindex fprefetch-loop-arrays +If supported by the target machine, generate instructions to prefetch +memory to improve the performance of loops that access large arrays. + +This option may generate better or worse code; results are highly +dependent on the structure of loops within the source code. + +@c APPLE LOCAL 4231761 -Oz +Disabled at levels @option{-Os} and @option{-Oz} (APPLE ONLY). + +@item -fno-peephole +@itemx -fno-peephole2 +@opindex fno-peephole +@opindex fno-peephole2 +Disable any machine-specific peephole optimizations. The difference +between @option{-fno-peephole} and @option{-fno-peephole2} is in how they +are implemented in the compiler; some targets use one, some use the +other, a few use both. + +@option{-fpeephole} is enabled by default. +@c APPLE LOCAL 4231761 -Oz +@option{-fpeephole2} enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fno-guess-branch-probability +@opindex fno-guess-branch-probability +Do not guess branch probabilities using heuristics. + +GCC will use heuristics to guess branch probabilities if they are +not provided by profiling feedback (@option{-fprofile-arcs}). These +heuristics are based on the control flow graph. If some branch probabilities +are specified by @samp{__builtin_expect}, then the heuristics will be +used to guess branch probabilities for the rest of the control flow graph, +taking the @samp{__builtin_expect} info into account. The interactions +between the heuristics and @samp{__builtin_expect} can be complex, and in +some cases, it may be useful to disable the heuristics so that the effects +of @samp{__builtin_expect} are easier to understand. + +The default is @option{-fguess-branch-probability} at levels +@c APPLE LOCAL 4231761 -Oz +@option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -freorder-blocks +@opindex freorder-blocks +Reorder basic blocks in the compiled function in order to reduce number of +taken branches and improve code locality. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -freorder-blocks-and-partition +@opindex freorder-blocks-and-partition +In addition to reordering basic blocks in the compiled function, in order +to reduce number of taken branches, partitions hot and cold basic blocks +into separate sections of the assembly and .o files, to improve +paging and cache locality performance. + +This optimization is automatically turned off in the presence of +exception handling, for linkonce sections, for functions with a user-defined +section attribute and on any architecture that does not support named +sections. + +@item -freorder-functions +@opindex freorder-functions +Reorder functions in the object file in order to +improve code locality. This is implemented by using special +subsections @code{.text.hot} for most frequently executed functions and +@code{.text.unlikely} for unlikely executed functions. Reordering is done by +the linker so object file format must support named sections and linker must +place them in a reasonable way. + +Also profile feedback must be available in to make this option effective. See +@option{-fprofile-arcs} for details. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fstrict-aliasing +@opindex fstrict-aliasing +Allows the compiler to assume the strictest aliasing rules applicable to +the language being compiled. For C (and C++), this activates +optimizations based on the type of expressions. In particular, an +object of one type is assumed never to reside at the same address as an +object of a different type, unless the types are almost the same. For +example, an @code{unsigned int} can alias an @code{int}, but not a +@code{void*} or a @code{double}. A character type may alias any other +type. + +Pay special attention to code like this: +@smallexample +union a_union @{ + int i; + double d; +@}; + +int f() @{ + a_union t; + t.d = 3.0; + return t.i; +@} +@end smallexample +The practice of reading from a different union member than the one most +recently written to (called ``type-punning'') is common. Even with +@option{-fstrict-aliasing}, type-punning is allowed, provided the memory +is accessed through the union type. So, the code above will work as +expected. However, this code might not: +@smallexample +int f() @{ + a_union t; + int* ip; + t.d = 3.0; + ip = &t.i; + return *ip; +@} +@end smallexample + +Every language that wishes to perform language-specific alias analysis +should define a function that computes, given an @code{tree} +node, an alias set for the node. Nodes in different alias sets are not +allowed to alias. For an example, see the C front-end function +@code{c_get_alias_set}. + +@c APPLE LOCAL 4231761 -Oz +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}, @option{-Oz} (APPLE ONLY). + +@item -fstrict-overflow +@opindex fstrict-overflow +Allow the compiler to assume strict signed overflow rules, depending +on the language being compiled. For C (and C++) this means that +overflow when doing arithmetic with signed numbers is undefined, which +means that the compiler may assume that it will not happen. This +permits various optimizations. For example, the compiler will assume +that an expression like @code{i + 10 > i} will always be true for +signed @code{i}. This assumption is only valid if signed overflow is +undefined, as the expression is false if @code{i + 10} overflows when +using twos complement arithmetic. When this option is in effect any +attempt to determine whether an operation on signed numbers will +overflow must be written carefully to not actually involve overflow. + +See also the @option{-fwrapv} option. Using @option{-fwrapv} means +that signed overflow is fully defined: it wraps. When +@option{-fwrapv} is used, there is no difference between +@option{-fstrict-overflow} and @option{-fno-strict-overflow}. With +@option{-fwrapv} certain types of overflow are permitted. For +example, if the compiler gets an overflow when doing arithmetic on +constants, the overflowed value can still be used with +@option{-fwrapv}, but not otherwise. + +The @option{-fstrict-overflow} option is enabled at levels +@option{-O2}, @option{-O3}, @option{-Os}. + +@item -falign-functions +@itemx -falign-functions=@var{n} +@opindex falign-functions +Align the start of functions to the next power-of-two greater than +@var{n}, skipping up to @var{n} bytes. For instance, +@option{-falign-functions=32} aligns functions to the next 32-byte +boundary, but @option{-falign-functions=24} would align to the next +32-byte boundary only if this can be done by skipping 23 bytes or less. + +@option{-fno-align-functions} and @option{-falign-functions=1} are +equivalent and mean that functions will not be aligned. + +Some assemblers only support this flag when @var{n} is a power of two; +in that case, it is rounded up. + +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -falign-labels +@itemx -falign-labels=@var{n} +@opindex falign-labels +Align all branch targets to a power-of-two boundary, skipping up to +@var{n} bytes like @option{-falign-functions}. This option can easily +make code slower, because it must insert dummy operations for when the +branch target is reached in the usual flow of the code. + +@option{-fno-align-labels} and @option{-falign-labels=1} are +equivalent and mean that labels will not be aligned. + +If @option{-falign-loops} or @option{-falign-jumps} are applicable and +are greater than this value, then their values are used instead. + +If @var{n} is not specified or is zero, use a machine-dependent default +which is very likely to be @samp{1}, meaning no alignment. + +Enabled at levels @option{-O2}, @option{-O3}. + +@c APPLE LOCAL begin -falign-loops-max-skip +@item -falign-loops-max-skip +@item -falign-loops-max-skip=@var{n} +@opindex falign-loops-max-skip +Align loops to a power-of-two boundary, but do not skip more than +@var{n} bytes to do so. +@c APPLE LOCAL end -falign-loops-max-skip + +@item -falign-loops +@itemx -falign-loops=@var{n} +@opindex falign-loops +Align loops to a power-of-two boundary, skipping up to @var{n} bytes +like @option{-falign-functions}. The hope is that the loop will be +executed many times, which will make up for any execution of the dummy +operations. + +@option{-fno-align-loops} and @option{-falign-loops=1} are +equivalent and mean that loops will not be aligned. + +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -falign-jumps +@itemx -falign-jumps=@var{n} +@opindex falign-jumps +Align branch targets to a power-of-two boundary, for branch targets +where the targets can only be reached by jumping, skipping up to @var{n} +bytes like @option{-falign-functions}. In this case, no dummy operations +need be executed. + +@c APPLE LOCAL begin -falign-jumps-max-skip +@item -falign-jumps-max-skip +@itemx -falign-jumps-max-skip=@var{n} +@opindex falign-jump-max-skips +Align branch targets to a power-of-two boundary, but do not skip more than +@var{n} bytes to do so. +@c APPLE LOCAL end -falign-jumps-max-skip + +@option{-fno-align-jumps} and @option{-falign-jumps=1} are +equivalent and mean that loops will not be aligned. + +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -funit-at-a-time +@opindex funit-at-a-time +Parse the whole compilation unit before starting to produce code. +This allows some extra optimizations to take place but consumes +more memory (in general). There are some compatibility issues +with @emph{unit-at-a-time} mode: +@itemize @bullet +@item +enabling @emph{unit-at-a-time} mode may change the order +in which functions, variables, and top-level @code{asm} statements +are emitted, and will likely break code relying on some particular +ordering. The majority of such top-level @code{asm} statements, +though, can be replaced by @code{section} attributes. The +@option{fno-toplevel-reorder} option may be used to keep the ordering +used in the input file, at the cost of some optimizations. + +@item +@emph{unit-at-a-time} mode removes unreferenced static variables +and functions. This may result in undefined references +when an @code{asm} statement refers directly to variables or functions +that are otherwise unused. In that case either the variable/function +shall be listed as an operand of the @code{asm} statement operand or, +in the case of top-level @code{asm} statements the attribute @code{used} +shall be used on the declaration. + +@item +Static functions now can use non-standard passing conventions that +may break @code{asm} statements calling functions directly. Again, +attribute @code{used} will prevent this behavior. +@end itemize + +As a temporary workaround, @option{-fno-unit-at-a-time} can be used, +but this scheme may not be supported by future releases of GCC@. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@item -fno-toplevel-reorder +Do not reorder top-level functions, variables, and @code{asm} +statements. Output them in the same order that they appear in the +input file. When this option is used, unreferenced static variables +will not be removed. This option is intended to support existing code +which relies on a particular ordering. For new code, it is better to +use attributes. + +@item -fweb +@opindex fweb +Constructs webs as commonly used for register allocation purposes and assign +each web individual pseudo register. This allows the register allocation pass +to operate on pseudos directly, but also strengthens several other optimization +passes, such as CSE, loop optimizer and trivial dead code remover. It can, +however, make debugging impossible, since variables will no longer stay in a +``home register''. + +Enabled by default with @option{-funroll-loops}. + +@item -fwhole-program +@opindex fwhole-program +Assume that the current compilation unit represents whole program being +compiled. All public functions and variables with the exception of @code{main} +and those merged by attribute @code{externally_visible} become static functions +and in a affect gets more aggressively optimized by interprocedural optimizers. +While this option is equivalent to proper use of @code{static} keyword for +programs consisting of single file, in combination with option +@option{--combine} this flag can be used to compile most of smaller scale C +programs since the functions and variables become local for the whole combined +compilation unit, not for the single source file itself. + + +@item -fno-cprop-registers +@opindex fno-cprop-registers +After register allocation and post-register allocation instruction splitting, +we perform a copy-propagation pass to try to reduce scheduling dependencies +and occasionally eliminate the copy. + +@c APPLE LOCAL begin 4231761 -Oz +Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}, +@option{-Oz} (APPLE ONLY). +@c APPLE LOCAL end 4231761 -Oz + +@item -fprofile-generate +@opindex fprofile-generate + +Enable options usually used for instrumenting application to produce +profile useful for later recompilation with profile feedback based +optimization. You must use @option{-fprofile-generate} both when +compiling and when linking your program. + +The following options are enabled: @code{-fprofile-arcs}, @code{-fprofile-values}, @code{-fvpt}. + +@item -fprofile-use +@opindex fprofile-use +Enable profile feedback directed optimizations, and optimizations +generally profitable only with profile feedback available. + +The following options are enabled: @code{-fbranch-probabilities}, @code{-fvpt}, +@code{-funroll-loops}, @code{-fpeel-loops}, @code{-ftracer} + +@end table + +The following options control compiler behavior regarding floating +point arithmetic. These options trade off between speed and +correctness. All must be specifically enabled. + +@table @gcctabopt +@item -ffloat-store +@opindex ffloat-store +Do not store floating point variables in registers, and inhibit other +options that might change whether a floating point value is taken from a +register or memory. + +@cindex floating point precision +This option prevents undesirable excess precision on machines such as +the 68000 where the floating registers (of the 68881) keep more +precision than a @code{double} is supposed to have. Similarly for the +x86 architecture. For most programs, the excess precision does only +good, but a few programs rely on the precise definition of IEEE floating +point. Use @option{-ffloat-store} for such programs, after modifying +them to store all pertinent intermediate computations into variables. + +@item -ffast-math +@opindex ffast-math +Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, @* +@option{-fno-trapping-math}, @option{-ffinite-math-only}, +@option{-fno-rounding-math}, @option{-fno-signaling-nans} +and @option{fcx-limited-range}. + +This option causes the preprocessor macro @code{__FAST_MATH__} to be defined. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +@item -fno-math-errno +@opindex fno-math-errno +Do not set ERRNO after calling math functions that are executed +with a single instruction, e.g., sqrt. A program that relies on +IEEE exceptions for math error handling may want to use this flag +for speed while maintaining IEEE arithmetic compatibility. + +@c APPLE LOCAL begin disable math-errno +@ignore +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-fmath-errno}. +@end ignore +(APPLE ONLY) The Darwin math libraries never set errno, so there is +no point in having the compiler generate code that assumes they +might. Therefore, the default is @option{-fno-math-errno} on Darwin. +@c APPLE LOCAL end disable math-errno + +On Darwin systems, the math library never sets @code{errno}. There is therefore +no reason for the compiler to consider the possibility that it might, +and @option{-fno-math-errno} is the default. + +@item -funsafe-math-optimizations +@opindex funsafe-math-optimizations +Allow optimizations for floating-point arithmetic that (a) assume +that arguments and results are valid and (b) may violate IEEE or +ANSI standards. When used at link-time, it may include libraries +or startup files that change the default FPU control word or other +similar optimizations. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-fno-unsafe-math-optimizations}. + +@item -ffinite-math-only +@opindex ffinite-math-only +Allow optimizations for floating-point arithmetic that assume +that arguments and results are not NaNs or +-Infs. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications. + +The default is @option{-fno-finite-math-only}. + +@item -fno-trapping-math +@opindex fno-trapping-math +Compile code assuming that floating-point operations cannot generate +user-visible traps. These traps include division by zero, overflow, +underflow, inexact result and invalid operation. This option implies +@option{-fno-signaling-nans}. Setting this option may allow faster +code if one relies on ``non-stop'' IEEE arithmetic, for example. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-ftrapping-math}. + +@item -frounding-math +@opindex frounding-math +Disable transformations and optimizations that assume default floating +point rounding behavior. This is round-to-zero for all floating point +to integer conversions, and round-to-nearest for all other arithmetic +truncations. This option should be specified for programs that change +the FP rounding mode dynamically, or that may be executed with a +non-default rounding mode. This option disables constant folding of +floating point expressions at compile-time (which may be affected by +rounding mode) and arithmetic transformations that are unsafe in the +presence of sign-dependent rounding modes. + +The default is @option{-fno-rounding-math}. + +This option is experimental and does not currently guarantee to +disable all GCC optimizations that are affected by rounding mode. +Future versions of GCC may provide finer control of this setting +using C99's @code{FENV_ACCESS} pragma. This command line option +will be used to specify the default state for @code{FENV_ACCESS}. + +@item -frtl-abstract-sequences +@opindex frtl-abstract-sequences +It is a size optimization method. This option is to find identical +sequences of code, which can be turned into pseudo-procedures and +then replace all occurrences with calls to the newly created +subroutine. It is kind of an opposite of @option{-finline-functions}. +This optimization runs at RTL level. + +@item -fsignaling-nans +@opindex fsignaling-nans +Compile code assuming that IEEE signaling NaNs may generate user-visible +traps during floating-point operations. Setting this option disables +optimizations that may change the number of exceptions visible with +signaling NaNs. This option implies @option{-ftrapping-math}. + +This option causes the preprocessor macro @code{__SUPPORT_SNAN__} to +be defined. + +The default is @option{-fno-signaling-nans}. + +This option is experimental and does not currently guarantee to +disable all GCC optimizations that affect signaling NaN behavior. + +@item -fsingle-precision-constant +@opindex fsingle-precision-constant +Treat floating point constant as single precision constant instead of +implicitly converting it to double precision constant. + +@item -fcx-limited-range +@itemx -fno-cx-limited-range +@opindex fcx-limited-range +@opindex fno-cx-limited-range +When enabled, this option states that a range reduction step is not +needed when performing complex division. The default is +@option{-fno-cx-limited-range}, but is enabled by @option{-ffast-math}. + +This option controls the default setting of the ISO C99 +@code{CX_LIMITED_RANGE} pragma. Nevertheless, the option applies to +all languages. + +@end table + +The following options control optimizations that may improve +performance, but are not enabled by any @option{-O} options. This +section includes experimental options that may produce broken code. + +@table @gcctabopt +@item -fbranch-probabilities +@opindex fbranch-probabilities +After running a program compiled with @option{-fprofile-arcs} +(@pxref{Debugging Options,, Options for Debugging Your Program or +@command{gcc}}), you can compile it a second time using +@option{-fbranch-probabilities}, to improve optimizations based on +the number of times each branch was taken. When the program +compiled with @option{-fprofile-arcs} exits it saves arc execution +counts to a file called @file{@var{sourcename}.gcda} for each source +file The information in this data file is very dependent on the +structure of the generated code, so you must use the same source code +and the same optimization options for both compilations. + +With @option{-fbranch-probabilities}, GCC puts a +@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}. +These can be used to improve optimization. Currently, they are only +used in one place: in @file{reorg.c}, instead of guessing which path a +branch is mostly to take, the @samp{REG_BR_PROB} values are used to +exactly determine which path is taken more often. + +@item -fprofile-values +@opindex fprofile-values +If combined with @option{-fprofile-arcs}, it adds code so that some +data about values of expressions in the program is gathered. + +With @option{-fbranch-probabilities}, it reads back the data gathered +from profiling values of expressions and adds @samp{REG_VALUE_PROFILE} +notes to instructions for their later usage in optimizations. + +Enabled with @option{-fprofile-generate} and @option{-fprofile-use}. + +@item -fvpt +@opindex fvpt +If combined with @option{-fprofile-arcs}, it instructs the compiler to add +a code to gather information about values of expressions. + +With @option{-fbranch-probabilities}, it reads back the data gathered +and actually performs the optimizations based on them. +Currently the optimizations include specialization of division operation +using the knowledge about the value of the denominator. + +@item -frename-registers +@opindex frename-registers +Attempt to avoid false dependencies in scheduled code by making use +of registers left over after register allocation. This optimization +will most benefit processors with lots of registers. Depending on the +debug information format adopted by the target, however, it can +make debugging impossible, since variables will no longer stay in +a ``home register''. + +Enabled by default with @option{-funroll-loops}. + +@item -ftracer +@opindex ftracer +Perform tail duplication to enlarge superblock size. This transformation +simplifies the control flow of the function allowing other optimizations to do +better job. + +Enabled with @option{-fprofile-use}. + +@item -funroll-loops +@opindex funroll-loops +Unroll loops whose number of iterations can be determined at compile time or +upon entry to the loop. @option{-funroll-loops} implies +@option{-frerun-cse-after-loop}, @option{-fweb} and @option{-frename-registers}. +It also turns on complete loop peeling (i.e.@: complete removal of loops with +small constant number of iterations). This option makes code larger, and may +or may not make it run faster. + +Enabled with @option{-fprofile-use}. + +@item -funroll-all-loops +@opindex funroll-all-loops +Unroll all loops, even if their number of iterations is uncertain when +the loop is entered. This usually makes programs run more slowly. +@option{-funroll-all-loops} implies the same options as +@option{-funroll-loops}. + +@item -fpeel-loops +@opindex fpeel-loops +Peels the loops for that there is enough information that they do not +roll much (from profile feedback). It also turns on complete loop peeling +(i.e.@: complete removal of loops with small constant number of iterations). + +Enabled with @option{-fprofile-use}. + +@item -fmove-loop-invariants +@opindex fmove-loop-invariants +Enables the loop invariant motion pass in the RTL loop optimizer. Enabled +at level @option{-O1} + +@item -funswitch-loops +@opindex funswitch-loops +Move branches with loop invariant conditions out of the loop, with duplicates +of the loop on both branches (modified according to result of the condition). + +@item -ffunction-sections +@itemx -fdata-sections +@opindex ffunction-sections +@opindex fdata-sections +Place each function or data item into its own section in the output +file if the target supports arbitrary sections. The name of the +function or the name of the data item determines the section's name +in the output file. + +Use these options on systems where the linker can perform optimizations +to improve locality of reference in the instruction space. Most systems +using the ELF object format and SPARC processors running Solaris 2 have +linkers with such optimizations. AIX may have these optimizations in +the future. + +Only use these options when there are significant benefits from doing +so. When you specify these options, the assembler and linker will +create larger object and executable files and will also be slower. +You will not be able to use @code{gprof} on all systems if you +specify this option and you may have problems with debugging if +you specify both this option and @option{-g}. + +@item -fbranch-target-load-optimize +@opindex fbranch-target-load-optimize +Perform branch target register load optimization before prologue / epilogue +threading. +The use of target registers can typically be exposed only during reload, +thus hoisting loads out of loops and doing inter-block scheduling needs +a separate optimization pass. + +@item -fbranch-target-load-optimize2 +@opindex fbranch-target-load-optimize2 +Perform branch target register load optimization after prologue / epilogue +threading. + +@item -fbtr-bb-exclusive +@opindex fbtr-bb-exclusive +When performing branch target register load optimization, don't reuse +branch target registers in within any basic block. + +@item -fstack-protector +Emit extra code to check for buffer overflows, such as stack smashing +attacks. This is done by adding a guard variable to functions with +vulnerable objects. This includes functions that call alloca, and +functions with buffers larger than 8 bytes. The guards are initialized +when a function is entered and then checked when the function exits. +If a guard check fails, an error message is printed and the program exits. + +@item -fstack-protector-all +Like @option{-fstack-protector} except that all functions are protected. + +@item -fsection-anchors +@opindex fsection-anchors +Try to reduce the number of symbolic address calculations by using +shared ``anchor'' symbols to address nearby objects. This transformation +can help to reduce the number of GOT entries and GOT accesses on some +targets. + +For example, the implementation of the following function @code{foo}: + +@smallexample +static int a, b, c; +int foo (void) @{ return a + b + c; @} +@end smallexample + +would usually calculate the addresses of all three variables, but if you +compile it with @option{-fsection-anchors}, it will access the variables +from a common anchor point instead. The effect is similar to the +following pseudocode (which isn't valid C): + +@smallexample +int foo (void) +@{ + register int *xr = &x; + return xr[&a - &x] + xr[&b - &x] + xr[&c - &x]; +@} +@end smallexample + +Not all targets support this option. + +@item --param @var{name}=@var{value} +@opindex param +In some places, GCC uses various constants to control the amount of +optimization that is done. For example, GCC will not inline functions +that contain more that a certain number of instructions. You can +control some of these constants on the command-line using the +@option{--param} option. + +The names of specific parameters, and the meaning of the values, are +tied to the internals of the compiler, and are subject to change +without notice in future releases. + +In each case, the @var{value} is an integer. The allowable choices for +@var{name} are given in the following table: + +@table @gcctabopt +@item salias-max-implicit-fields +The maximum number of fields in a variable without direct +structure accesses for which structure aliasing will consider trying +to track each field. The default is 5 + +@item salias-max-array-elements +The maximum number of elements an array can have and its elements +still be tracked individually by structure aliasing. The default is 4 + +@item sra-max-structure-size +The maximum structure size, in bytes, at which the scalar replacement +of aggregates (SRA) optimization will perform block copies. The +default value, 0, implies that GCC will select the most appropriate +size itself. + +@item sra-field-structure-ratio +The threshold ratio (as a percentage) between instantiated fields and +the complete structure size. We say that if the ratio of the number +of bytes in instantiated fields to the number of bytes in the complete +structure exceeds this parameter, then block copies are not used. The +default is 75. + +@item max-crossjump-edges +The maximum number of incoming edges to consider for crossjumping. +The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in +the number of edges incoming to each block. Increasing values mean +more aggressive optimization, making the compile time increase with +probably small improvement in executable size. + +@item min-crossjump-insns +The minimum number of instructions which must be matched at the end +of two blocks before crossjumping will be performed on them. This +value is ignored in the case where all instructions in the block being +crossjumped from are matched. The default value is 5. + +@item max-grow-copy-bb-insns +The maximum code size expansion factor when copying basic blocks +instead of jumping. The expansion is relative to a jump instruction. +The default value is 8. + +@item max-goto-duplication-insns +The maximum number of instructions to duplicate to a block that jumps +to a computed goto. To avoid @math{O(N^2)} behavior in a number of +passes, GCC factors computed gotos early in the compilation process, +and unfactors them as late as possible. Only computed jumps at the +end of a basic blocks with no more than max-goto-duplication-insns are +unfactored. The default value is 8. + +@item max-delay-slot-insn-search +The maximum number of instructions to consider when looking for an +instruction to fill a delay slot. If more than this arbitrary number of +instructions is searched, the time savings from filling the delay slot +will be minimal so stop searching. Increasing values mean more +aggressive optimization, making the compile time increase with probably +small improvement in executable run time. + +@item max-delay-slot-live-search +When trying to fill delay slots, the maximum number of instructions to +consider when searching for a block with valid live register +information. Increasing this arbitrarily chosen value means more +aggressive optimization, increasing the compile time. This parameter +should be removed when the delay slot code is rewritten to maintain the +control-flow graph. + +@item max-gcse-memory +The approximate maximum amount of memory that will be allocated in +order to perform the global common subexpression elimination +optimization. If more memory than specified is required, the +optimization will not be done. + +@item max-gcse-passes +The maximum number of passes of GCSE to run. The default is 1. + +@item max-pending-list-length +The maximum number of pending dependencies scheduling will allow +before flushing the current state and starting over. Large functions +with few branches or calls can create excessively large lists which +needlessly consume memory and resources. + +@item max-inline-insns-single +Several parameters control the tree inliner used in gcc. +This number sets the maximum number of instructions (counted in GCC's +internal representation) in a single function that the tree inliner +will consider for inlining. This only affects functions declared +inline and methods implemented in a class declaration (C++). +The default value is 450. + +@item max-inline-insns-auto +When you use @option{-finline-functions} (included in @option{-O3}), +a lot of functions that would otherwise not be considered for inlining +by the compiler will be investigated. To those functions, a different +(more restrictive) limit compared to functions declared inline can +be applied. +The default value is 90. + +@item large-function-insns +The limit specifying really large functions. For functions larger than this +limit after inlining inlining is constrained by +@option{--param large-function-growth}. This parameter is useful primarily +to avoid extreme compilation time caused by non-linear algorithms used by the +backend. +This parameter is ignored when @option{-funit-at-a-time} is not used. +The default value is 2700. + +@item large-function-growth +Specifies maximal growth of large function caused by inlining in percents. +This parameter is ignored when @option{-funit-at-a-time} is not used. +The default value is 100 which limits large function growth to 2.0 times +the original size. + +@item large-unit-insns +The limit specifying large translation unit. Growth caused by inlining of +units larger than this limit is limited by @option{--param inline-unit-growth}. +For small units this might be too tight (consider unit consisting of function A +that is inline and B that just calls A three time. If B is small relative to +A, the growth of unit is 300\% and yet such inlining is very sane. For very +large units consisting of small inlininable functions however the overall unit +growth limit is needed to avoid exponential explosion of code size. Thus for +smaller units, the size is increased to @option{--param large-unit-insns} +before applying @option{--param inline-unit-growth}. The default is 10000 + +@item inline-unit-growth +Specifies maximal overall growth of the compilation unit caused by inlining. +This parameter is ignored when @option{-funit-at-a-time} is not used. +The default value is 50 which limits unit growth to 1.5 times the original +size. + +@item max-inline-insns-recursive +@itemx max-inline-insns-recursive-auto +Specifies maximum number of instructions out-of-line copy of self recursive inline +function can grow into by performing recursive inlining. + +For functions declared inline @option{--param max-inline-insns-recursive} is +taken into account. For function not declared inline, recursive inlining +happens only when @option{-finline-functions} (included in @option{-O3}) is +enabled and @option{--param max-inline-insns-recursive-auto} is used. The +default value is 450. + +@item max-inline-recursive-depth +@itemx max-inline-recursive-depth-auto +Specifies maximum recursion depth used by the recursive inlining. + +For functions declared inline @option{--param max-inline-recursive-depth} is +taken into account. For function not declared inline, recursive inlining +happens only when @option{-finline-functions} (included in @option{-O3}) is +enabled and @option{--param max-inline-recursive-depth-auto} is used. The +default value is 450. + +@item min-inline-recursive-probability +Recursive inlining is profitable only for function having deep recursion +in average and can hurt for function having little recursion depth by +increasing the prologue size or complexity of function body to other +optimizers. + +When profile feedback is available (see @option{-fprofile-generate}) the actual +recursion depth can be guessed from probability that function will recurse via +given call expression. This parameter limits inlining only to call expression +whose probability exceeds given threshold (in percents). The default value is +10. + +@item inline-call-cost +Specify cost of call instruction relative to simple arithmetics operations +(having cost of 1). Increasing this cost disqualifies inlining of non-leaf +functions and at the same time increases size of leaf function that is believed to +reduce function size by being inlined. In effect it increases amount of +inlining for code having large abstraction penalty (many functions that just +pass the arguments to other functions) and decrease inlining for code with low +abstraction penalty. The default value is 16. + +@item max-unrolled-insns +The maximum number of instructions that a loop should have if that loop +is unrolled, and if the loop is unrolled, it determines how many times +the loop code is unrolled. + +@item max-average-unrolled-insns +The maximum number of instructions biased by probabilities of their execution +that a loop should have if that loop is unrolled, and if the loop is unrolled, +it determines how many times the loop code is unrolled. + +@item max-unroll-times +The maximum number of unrollings of a single loop. + +@item max-peeled-insns +The maximum number of instructions that a loop should have if that loop +is peeled, and if the loop is peeled, it determines how many times +the loop code is peeled. + +@item max-peel-times +The maximum number of peelings of a single loop. + +@item max-completely-peeled-insns +The maximum number of insns of a completely peeled loop. + +@item max-completely-peel-times +The maximum number of iterations of a loop to be suitable for complete peeling. + +@item max-unswitch-insns +The maximum number of insns of an unswitched loop. + +@item max-unswitch-level +The maximum number of branches unswitched in a single loop. + +@item lim-expensive +The minimum cost of an expensive expression in the loop invariant motion. + +@item iv-consider-all-candidates-bound +Bound on number of candidates for induction variables below that +all candidates are considered for each use in induction variable +optimizations. Only the most relevant candidates are considered +if there are more candidates, to avoid quadratic time complexity. + +@item iv-max-considered-uses +The induction variable optimizations give up on loops that contain more +induction variable uses. + +@item iv-always-prune-cand-set-bound +If number of candidates in the set is smaller than this value, +we always try to remove unnecessary ivs from the set during its +optimization when a new iv is added to the set. + +@item scev-max-expr-size +Bound on size of expressions used in the scalar evolutions analyzer. +Large expressions slow the analyzer. + +@item vect-max-version-checks +The maximum number of runtime checks that can be performed when doing +loop versioning in the vectorizer. See option ftree-vect-loop-version +for more information. + +@item max-iterations-to-track + +The maximum number of iterations of a loop the brute force algorithm +for analysis of # of iterations of the loop tries to evaluate. + +@item hot-bb-count-fraction +Select fraction of the maximal count of repetitions of basic block in program +given basic block needs to have to be considered hot. + +@item hot-bb-frequency-fraction +Select fraction of the maximal frequency of executions of basic block in +function given basic block needs to have to be considered hot + +@item max-predicted-iterations +The maximum number of loop iterations we predict statically. This is useful +in cases where function contain single loop with known bound and other loop +with unknown. We predict the known number of iterations correctly, while +the unknown number of iterations average to roughly 10. This means that the +loop without bounds would appear artificially cold relative to the other one. + +@item tracer-dynamic-coverage +@itemx tracer-dynamic-coverage-feedback + +This value is used to limit superblock formation once the given percentage of +executed instructions is covered. This limits unnecessary code size +expansion. + +The @option{tracer-dynamic-coverage-feedback} is used only when profile +feedback is available. The real profiles (as opposed to statically estimated +ones) are much less balanced allowing the threshold to be larger value. + +@item tracer-max-code-growth +Stop tail duplication once code growth has reached given percentage. This is +rather hokey argument, as most of the duplicates will be eliminated later in +cross jumping, so it may be set to much higher values than is the desired code +growth. + +@item tracer-min-branch-ratio + +Stop reverse growth when the reverse probability of best edge is less than this +threshold (in percent). + +@item tracer-min-branch-ratio +@itemx tracer-min-branch-ratio-feedback + +Stop forward growth if the best edge do have probability lower than this +threshold. + +Similarly to @option{tracer-dynamic-coverage} two values are present, one for +compilation for profile feedback and one for compilation without. The value +for compilation with profile feedback needs to be more conservative (higher) in +order to make tracer effective. + +@item max-cse-path-length + +Maximum number of basic blocks on path that cse considers. The default is 10. + +@item max-cse-insns +The maximum instructions CSE process before flushing. The default is 1000. + +@item global-var-threshold + +Counts the number of function calls (@var{n}) and the number of +call-clobbered variables (@var{v}). If @var{n}x@var{v} is larger than this limit, a +single artificial variable will be created to represent all the +call-clobbered variables at function call sites. This artificial +variable will then be made to alias every call-clobbered variable. +(done as @code{int * size_t} on the host machine; beware overflow). + +@item max-aliased-vops + +Maximum number of virtual operands allowed to represent aliases +before triggering the alias grouping heuristic. Alias grouping +reduces compile times and memory consumption needed for aliasing at +the expense of precision loss in alias information. + +@item ggc-min-expand + +GCC uses a garbage collector to manage its own memory allocation. This +parameter specifies the minimum percentage by which the garbage +collector's heap should be allowed to expand between collections. +Tuning this may improve compilation speed; it has no effect on code +generation. + +The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when +RAM >= 1GB@. If @code{getrlimit} is available, the notion of "RAM" is +the smallest of actual RAM and @code{RLIMIT_DATA} or @code{RLIMIT_AS}. If +GCC is not able to calculate RAM on a particular platform, the lower +bound of 30% is used. Setting this parameter and +@option{ggc-min-heapsize} to zero causes a full collection to occur at +every opportunity. This is extremely slow, but can be useful for +debugging. + +@item ggc-min-heapsize + +Minimum size of the garbage collector's heap before it begins bothering +to collect garbage. The first collection occurs after the heap expands +by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}. Again, +tuning this may improve compilation speed, and has no effect on code +generation. + +The default is the smaller of RAM/8, RLIMIT_RSS, or a limit which +tries to ensure that RLIMIT_DATA or RLIMIT_AS are not exceeded, but +with a lower bound of 4096 (four megabytes) and an upper bound of +131072 (128 megabytes). If GCC is not able to calculate RAM on a +particular platform, the lower bound is used. Setting this parameter +very large effectively disables garbage collection. Setting this +parameter and @option{ggc-min-expand} to zero causes a full collection +to occur at every opportunity. + +@item max-reload-search-insns +The maximum number of instruction reload should look backward for equivalent +register. Increasing values mean more aggressive optimization, making the +compile time increase with probably slightly better performance. The default +value is 100. + +@item max-cselib-memory-locations +The maximum number of memory locations cselib should take into account. +Increasing values mean more aggressive optimization, making the compile time +increase with probably slightly better performance. The default value is 500. + +@item max-flow-memory-locations +Similar as @option{max-cselib-memory-locations} but for dataflow liveness. +The default value is 100. + +@item reorder-blocks-duplicate +@itemx reorder-blocks-duplicate-feedback + +Used by basic block reordering pass to decide whether to use unconditional +branch or duplicate the code on its destination. Code is duplicated when its +estimated size is smaller than this value multiplied by the estimated size of +unconditional jump in the hot spots of the program. + +The @option{reorder-block-duplicate-feedback} is used only when profile +feedback is available and may be set to higher values than +@option{reorder-block-duplicate} since information about the hot spots is more +accurate. + +@item max-sched-ready-insns +The maximum number of instructions ready to be issued the scheduler should +consider at any given time during the first scheduling pass. Increasing +values mean more thorough searches, making the compilation time increase +with probably little benefit. The default value is 100. + +@item max-sched-region-blocks +The maximum number of blocks in a region to be considered for +interblock scheduling. The default value is 10. + +@item max-sched-region-insns +The maximum number of insns in a region to be considered for +interblock scheduling. The default value is 100. + +@item min-spec-prob +The minimum probability (in percents) of reaching a source block +for interblock speculative scheduling. The default value is 40. + +@item max-sched-extend-regions-iters +The maximum number of iterations through CFG to extend regions. +0 - disable region extension, +N - do at most N iterations. +The default value is 0. + +@item max-sched-insn-conflict-delay +The maximum conflict delay for an insn to be considered for speculative motion. +The default value is 3. + +@item sched-spec-prob-cutoff +The minimal probability of speculation success (in percents), so that +speculative insn will be scheduled. +The default value is 40. + +@item max-last-value-rtl + +The maximum size measured as number of RTLs that can be recorded in an expression +in combiner for a pseudo register as last known value of that register. The default +is 10000. + +@item integer-share-limit +Small integer constants can use a shared data structure, reducing the +compiler's memory usage and increasing its speed. This sets the maximum +value of a shared integer constant's. The default value is 256. + +@item min-virtual-mappings +Specifies the minimum number of virtual mappings in the incremental +SSA updater that should be registered to trigger the virtual mappings +heuristic defined by virtual-mappings-ratio. The default value is +100. + +@item virtual-mappings-ratio +If the number of virtual mappings is virtual-mappings-ratio bigger +than the number of virtual symbols to be updated, then the incremental +SSA updater switches to a full update for those symbols. The default +ratio is 3. + +@item ssp-buffer-size +The minimum size of buffers (i.e. arrays) that will receive stack smashing +protection when @option{-fstack-protection} is used. + +@item max-jump-thread-duplication-stmts +Maximum number of statements allowed in a block that needs to be +duplicated when threading jumps. + +@item max-fields-for-field-sensitive +Maximum number of fields in a structure we will treat in +a field sensitive manner during pointer analysis. + +@end table +@end table + +@node Preprocessor Options +@section Options Controlling the Preprocessor +@cindex preprocessor options +@cindex options, preprocessor + +These options control the C preprocessor, which is run on each C source +file before actual compilation. + +If you use the @option{-E} option, nothing is done except preprocessing. +Some of these options make sense only together with @option{-E} because +they cause the preprocessor output to be unsuitable for actual +compilation. + +@table @gcctabopt +@c APPLE LOCAL pod error 6089368 +@item -Wp,@var{option} +@opindex Wp +You can use @option{-Wp,@var{option}} to bypass the compiler driver +and pass @var{option} directly through to the preprocessor. If +@var{option} contains commas, it is split into multiple options at the +commas. However, many options are modified, translated or interpreted +by the compiler driver before being passed to the preprocessor, and +@option{-Wp} forcibly bypasses this phase. The preprocessor's direct +interface is undocumented and subject to change, so whenever possible +you should avoid using @option{-Wp} and let the driver handle the +options instead. + +@item -Xpreprocessor @var{option} +@opindex preprocessor +Pass @var{option} as an option to the preprocessor. You can use this to +supply system-specific preprocessor options which GCC does not know how to +recognize. + +If you want to pass an option that takes an argument, you must use +@option{-Xpreprocessor} twice, once for the option and once for the argument. +@end table + +@include cppopts.texi + +@node Assembler Options +@section Passing Options to the Assembler + +@c prevent bad page break with this line +You can pass options to the assembler. + +@table @gcctabopt +@item -Wa,@var{option} +@opindex Wa +Pass @var{option} as an option to the assembler. If @var{option} +contains commas, it is split into multiple options at the commas. + +@item -Xassembler @var{option} +@opindex Xassembler +Pass @var{option} as an option to the assembler. You can use this to +supply system-specific assembler options which GCC does not know how to +recognize. + +If you want to pass an option that takes an argument, you must use +@option{-Xassembler} twice, once for the option and once for the argument. + +@end table + +@node Link Options +@section Options for Linking +@cindex link options +@cindex options, linking + +These options come into play when the compiler links object files into +an executable output file. They are meaningless if the compiler is +not doing a link step. + +@c APPLE LOCAL begin linker flags +In addition to the options listed below, Apple's GCC also accepts and +passes nearly all of the options defined by the linker @samp{ld} and by +the library tool @samp{libtool}. Common options include +@samp{-framework}, @samp{-dynamic}, @samp{-bundle}, +@samp{-flat_namespace}, and so forth. See the ld and libtool man pages +for further details. +@c APPLE LOCAL end linker flags + +@table @gcctabopt +@cindex file names +@item @var{object-file-name} +A file name that does not end in a special recognized suffix is +considered to name an object file or library. (Object files are +distinguished from libraries by the linker according to the file +contents.) If linking is done, these object files are used as input +to the linker. + +@item -c +@itemx -S +@itemx -E +@opindex c +@opindex S +@opindex E +If any of these options is used, then the linker is not run, and +object file names should not be used as arguments. @xref{Overall +Options}. + +@cindex Libraries +@item -l@var{library} +@itemx -l @var{library} +@opindex l +Search the library named @var{library} when linking. (The second +alternative with the library as a separate argument is only for +POSIX compliance and is not recommended.) + +It makes a difference where in the command you write this option; the +linker searches and processes libraries and object files in the order they +are specified. Thus, @samp{foo.o -lz bar.o} searches library @samp{z} +after file @file{foo.o} but before @file{bar.o}. If @file{bar.o} refers +to functions in @samp{z}, those functions may not be loaded. + +The linker searches a standard list of directories for the library, +which is actually a file named @file{lib@var{library}.a}. The linker +then uses this file as if it had been specified precisely by name. + +The directories searched include several standard system directories +plus any that you specify with @option{-L}. + +Normally the files found this way are library files---archive files +whose members are object files. The linker handles an archive file by +scanning through it for members which define symbols that have so far +been referenced but not defined. But if the file that is found is an +ordinary object file, it is linked in the usual fashion. The only +difference between using an @option{-l} option and specifying a file name +is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a} +and searches several directories. + +@item -lobjc +@opindex lobjc +You need this special case of the @option{-l} option in order to +link an Objective-C or Objective-C++ program. + +@item -nostartfiles +@opindex nostartfiles +Do not use the standard system startup files when linking. +The standard system libraries are used normally, unless @option{-nostdlib} +or @option{-nodefaultlibs} is used. + +@item -nodefaultlibs +@opindex nodefaultlibs +Do not use the standard system libraries when linking. +Only the libraries you specify will be passed to the linker. +The standard startup files are used normally, unless @option{-nostartfiles} +is used. The compiler may generate calls to @code{memcmp}, +@code{memset}, @code{memcpy} and @code{memmove}. +These entries are usually resolved by entries in +libc. These entry points should be supplied through some other +mechanism when this option is specified. + +@item -nostdlib +@opindex nostdlib +Do not use the standard system startup files or libraries when linking. +No startup files and only the libraries you specify will be passed to +the linker. The compiler may generate calls to @code{memcmp}, @code{memset}, +@code{memcpy} and @code{memmove}. +These entries are usually resolved by entries in +libc. These entry points should be supplied through some other +mechanism when this option is specified. + +@cindex @option{-lgcc}, use with @option{-nostdlib} +@cindex @option{-nostdlib} and unresolved references +@cindex unresolved references and @option{-nostdlib} +@cindex @option{-lgcc}, use with @option{-nodefaultlibs} +@cindex @option{-nodefaultlibs} and unresolved references +@cindex unresolved references and @option{-nodefaultlibs} +One of the standard libraries bypassed by @option{-nostdlib} and +@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines +that GCC uses to overcome shortcomings of particular machines, or special +needs for some languages. +(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler +Collection (GCC) Internals}, +for more discussion of @file{libgcc.a}.) +In most cases, you need @file{libgcc.a} even when you want to avoid +other standard libraries. In other words, when you specify @option{-nostdlib} +or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well. +This ensures that you have no unresolved references to internal GCC +library subroutines. (For example, @samp{__main}, used to ensure C++ +constructors will be called; @pxref{Collect2,,@code{collect2}, gccint, +GNU Compiler Collection (GCC) Internals}.) + +@item -pie +@opindex pie +Produce a position independent executable on targets which support it. +For predictable results, you must also specify the same set of options +that were used to generate code (@option{-fpie}, @option{-fPIE}, +or model suboptions) when you specify this option. + +@item -rdynamic +@opindex rdynamic +Pass the flag @option{-export-dynamic} to the ELF linker, on targets +that support it. This instructs the linker to add all symbols, not +only used ones, to the dynamic symbol table. This option is needed +for some uses of @code{dlopen} or to allow obtaining backtraces +from within a program. + +@item -s +@opindex s +Remove all symbol table and relocation information from the executable. + +@item -static +@opindex static +On systems that support dynamic linking, this prevents linking with the shared +libraries. On other systems, this option has no effect. + +@c APPLE LOCAL begin manual +This option will not work on Mac OS X unless all libraries (including +@file{libgcc.a}) have also been compiled with @option{-static}. Since +neither a static version of libSystem.dylib nor crt0.o are provided, this +option is not useful to most people. +@c APPLE LOCAL end manual + +@item -shared +@opindex shared +Produce a shared object which can then be linked with other objects to +form an executable. Not all systems support this option. For predictable +results, you must also specify the same set of options that were used to +generate code (@option{-fpic}, @option{-fPIC}, or model suboptions) +when you specify this option.@footnote{On some systems, @samp{gcc -shared} +needs to build supplementary stub code for constructors to work. On +multi-libbed systems, @samp{gcc -shared} must select the correct support +libraries to link against. Failing to supply the correct flags may lead +to subtle defects. Supplying them in cases where they are not necessary +is innocuous.} + +@c APPLE LOCAL begin manual +This option is not supported on Mac OS X. +@c APPLE LOCAL end manual + +@item -shared-libgcc +@itemx -static-libgcc +@opindex shared-libgcc +@opindex static-libgcc +On systems that provide @file{libgcc} as a shared library, these options +force the use of either the shared or static version respectively. +If no shared version of @file{libgcc} was built when the compiler was +configured, these options have no effect. + +There are several situations in which an application should use the +shared @file{libgcc} instead of the static version. The most common +of these is when the application wishes to throw and catch exceptions +across different shared libraries. In that case, each of the libraries +as well as the application itself should use the shared @file{libgcc}. + +Therefore, the G++ and GCJ drivers automatically add +@option{-shared-libgcc} whenever you build a shared library or a main +executable, because C++ and Java programs typically use exceptions, so +this is the right thing to do. + +If, instead, you use the GCC driver to create shared libraries, you may +find that they will not always be linked with the shared @file{libgcc}. +If GCC finds, at its configuration time, that you have a non-GNU linker +or a GNU linker that does not support option @option{--eh-frame-hdr}, +it will link the shared version of @file{libgcc} into shared libraries +by default. Otherwise, it will take advantage of the linker and optimize +away the linking with the shared version of @file{libgcc}, linking with +the static version of libgcc by default. This allows exceptions to +propagate through such shared libraries, without incurring relocation +costs at library load time. + +However, if a library or main executable is supposed to throw or catch +exceptions, you must link it using the G++ or GCJ driver, as appropriate +for the languages used in the program, or using the option +@option{-shared-libgcc}, such that it is linked with the shared +@file{libgcc}. + +@item -symbolic +@opindex symbolic +Bind references to global symbols when building a shared object. Warn +about any unresolved references (unless overridden by the link editor +option @samp{-Xlinker -z -Xlinker defs}). Only a few systems support +this option. + +@item -Xlinker @var{option} +@opindex Xlinker +Pass @var{option} as an option to the linker. You can use this to +supply system-specific linker options which GCC does not know how to +recognize. + +If you want to pass an option that takes an argument, you must use +@option{-Xlinker} twice, once for the option and once for the argument. +For example, to pass @option{-assert definitions}, you must write +@samp{-Xlinker -assert -Xlinker definitions}. It does not work to write +@option{-Xlinker "-assert definitions"}, because this passes the entire +string as a single argument, which is not what the linker expects. + +@item -Wl,@var{option} +@opindex Wl +Pass @var{option} as an option to the linker. If @var{option} contains +commas, it is split into multiple options at the commas. + +@item -u @var{symbol} +@opindex u +Pretend the symbol @var{symbol} is undefined, to force linking of +library modules to define it. You can use @option{-u} multiple times with +different symbols to force loading of additional library modules. +@end table + +@node Directory Options +@section Options for Directory Search +@cindex directory options +@cindex options, directory search +@cindex search path + +These options specify directories to search for header files, for +libraries and for parts of the compiler: + +@table @gcctabopt +@item -I@var{dir} +@opindex I +Add the directory @var{dir} to the head of the list of directories to be +searched for header files. This can be used to override a system header +file, substituting your own version, since these directories are +searched before the system header file directories. However, you should +not use this option to add directories that contain vendor-supplied +system header files (use @option{-isystem} for that). If you use more than +one @option{-I} option, the directories are scanned in left-to-right +order; the standard system directories come after. + +If a standard system include directory, or a directory specified with +@option{-isystem}, is also specified with @option{-I}, the @option{-I} +option will be ignored. The directory will still be searched but as a +system directory at its normal position in the system include chain. +This is to ensure that GCC's procedure to fix buggy system headers and +the ordering for the include_next directive are not inadvertently changed. +If you really need to change the search order for system directories, +use the @option{-nostdinc} and/or @option{-isystem} options. + +@c APPLE LOCAL begin ARM iwithsysroot 4917039 +The option @option{-iwithsysroot} (APPLE ONLY), if specified with an +absolute path, will prepend the system root directory (if applicable) to +the path and add it to the beginning of the system search paths. If +specified with a relative path, @option{-iwithsysroot} will behave +identically to @option{-isystem}. +@c APPLE LOCAL end ARM iwithsysroot 4917039 + +@item -iquote@var{dir} +@opindex iquote +Add the directory @var{dir} to the head of the list of directories to +be searched for header files only for the case of @samp{#include +"@var{file}"}; they are not searched for @samp{#include <@var{file}>}, +otherwise just like @option{-I}. + +@item -L@var{dir} +@opindex L +Add directory @var{dir} to the list of directories to be searched +for @option{-l}. + +@item -B@var{prefix} +@opindex B +This option specifies where to find the executables, libraries, +include files, and data files of the compiler itself. + +The compiler driver program runs one or more of the subprograms +@file{cpp}, @file{cc1}, @file{as} and @file{ld}. It tries +@var{prefix} as a prefix for each program it tries to run, both with and +without @samp{@var{machine}/@var{version}/} (@pxref{Target Options}). + +For each subprogram to be run, the compiler driver first tries the +@option{-B} prefix, if any. If that name is not found, or if @option{-B} +was not specified, the driver tries two standard prefixes, which are +@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc/}. If neither of +those results in a file name that is found, the unmodified program +name is searched for using the directories specified in your +@env{PATH} environment variable. + +The compiler will check to see if the path provided by the @option{-B} +refers to a directory, and if necessary it will add a directory +separator character at the end of the path. + +@option{-B} prefixes that effectively specify directory names also apply +to libraries in the linker, because the compiler translates these +options into @option{-L} options for the linker. They also apply to +includes files in the preprocessor, because the compiler translates these +options into @option{-isystem} options for the preprocessor. In this case, +the compiler appends @samp{include} to the prefix. + +The run-time support file @file{libgcc.a} can also be searched for using +the @option{-B} prefix, if needed. If it is not found there, the two +standard prefixes above are tried, and that is all. The file is left +out of the link if it is not found by those means. + +Another way to specify a prefix much like the @option{-B} prefix is to use +the environment variable @env{GCC_EXEC_PREFIX}. @xref{Environment +Variables}. + +As a special kludge, if the path provided by @option{-B} is +@file{[dir/]stage@var{N}/}, where @var{N} is a number in the range 0 to +9, then it will be replaced by @file{[dir/]include}. This is to help +with boot-strapping the compiler. + +@item -specs=@var{file} +@opindex specs +Process @var{file} after the compiler reads in the standard @file{specs} +file, in order to override the defaults that the @file{gcc} driver +program uses when determining what switches to pass to @file{cc1}, +@file{cc1plus}, @file{as}, @file{ld}, etc. More than one +@option{-specs=@var{file}} can be specified on the command line, and they +are processed in order, from left to right. + +@item --sysroot=@var{dir} +@opindex sysroot +Use @var{dir} as the logical root directory for headers and libraries. +For example, if the compiler would normally search for headers in +@file{/usr/include} and libraries in @file{/usr/lib}, it will instead +search @file{@var{dir}/usr/include} and @file{@var{dir}/usr/lib}. + +With Apple's version of GCC, this option is effectively replaced by +@option{-isysroot}, which you should use instead of @option{--sysroot}. +For other (non-Apple) versions of GCC, +if you use both this option and the @option{-isysroot} option, then +the @option{--sysroot} option will apply to libraries, but the +@option{-isysroot} option will apply to header files. + +The GNU linker (beginning with version 2.16) has the necessary support +for this option. If your linker does not support this option, the +header file aspect of @option{--sysroot} will still work, but the +library aspect will not. + +@item -I- +@opindex I- +This option has been deprecated. Please use @option{-iquote} instead for +@option{-I} directories before the @option{-I-} and remove the @option{-I-}. +Any directories you specify with @option{-I} options before the @option{-I-} +option are searched only for the case of @samp{#include "@var{file}"}; +they are not searched for @samp{#include <@var{file}>}. + +If additional directories are specified with @option{-I} options after +the @option{-I-}, these directories are searched for all @samp{#include} +directives. (Ordinarily @emph{all} @option{-I} directories are used +this way.) + +In addition, the @option{-I-} option inhibits the use of the current +directory (where the current input file came from) as the first search +directory for @samp{#include "@var{file}"}. There is no way to +override this effect of @option{-I-}. With @option{-I.} you can specify +searching the directory which was current when the compiler was +invoked. That is not exactly the same as what the preprocessor does +by default, but it is often satisfactory. + +@option{-I-} does not inhibit the use of the standard system directories +for header files. Thus, @option{-I-} and @option{-nostdinc} are +independent. +@end table + +@c man end + +@node Spec Files +@section Specifying subprocesses and the switches to pass to them +@cindex Spec Files + +@command{gcc} is a driver program. It performs its job by invoking a +sequence of other programs to do the work of compiling, assembling and +linking. GCC interprets its command-line parameters and uses these to +deduce which programs it should invoke, and which command-line options +it ought to place on their command lines. This behavior is controlled +by @dfn{spec strings}. In most cases there is one spec string for each +program that GCC can invoke, but a few programs have multiple spec +strings to control their behavior. The spec strings built into GCC can +be overridden by using the @option{-specs=} command-line switch to specify +a spec file. + +@dfn{Spec files} are plaintext files that are used to construct spec +strings. They consist of a sequence of directives separated by blank +lines. The type of directive is determined by the first non-whitespace +character on the line and it can be one of the following: + +@table @code +@item %@var{command} +Issues a @var{command} to the spec file processor. The commands that can +appear here are: + +@table @code +@item %include <@var{file}> +@cindex %include +Search for @var{file} and insert its text at the current point in the +specs file. + +@item %include_noerr <@var{file}> +@cindex %include_noerr +Just like @samp{%include}, but do not generate an error message if the include +file cannot be found. + +@item %rename @var{old_name} @var{new_name} +@cindex %rename +Rename the spec string @var{old_name} to @var{new_name}. + +@end table + +@item *[@var{spec_name}]: +This tells the compiler to create, override or delete the named spec +string. All lines after this directive up to the next directive or +blank line are considered to be the text for the spec string. If this +results in an empty string then the spec will be deleted. (Or, if the +spec did not exist, then nothing will happened.) Otherwise, if the spec +does not currently exist a new spec will be created. If the spec does +exist then its contents will be overridden by the text of this +directive, unless the first character of that text is the @samp{+} +character, in which case the text will be appended to the spec. + +@item [@var{suffix}]: +Creates a new @samp{[@var{suffix}] spec} pair. All lines after this directive +and up to the next directive or blank line are considered to make up the +spec string for the indicated suffix. When the compiler encounters an +input file with the named suffix, it will processes the spec string in +order to work out how to compile that file. For example: + +@smallexample +.ZZ: +z-compile -input %i +@end smallexample + +This says that any input file whose name ends in @samp{.ZZ} should be +passed to the program @samp{z-compile}, which should be invoked with the +command-line switch @option{-input} and with the result of performing the +@samp{%i} substitution. (See below.) + +As an alternative to providing a spec string, the text that follows a +suffix directive can be one of the following: + +@table @code +@item @@@var{language} +This says that the suffix is an alias for a known @var{language}. This is +similar to using the @option{-x} command-line switch to GCC to specify a +language explicitly. For example: + +@smallexample +.ZZ: +@@c++ +@end smallexample + +Says that .ZZ files are, in fact, C++ source files. + +@item #@var{name} +This causes an error messages saying: + +@smallexample +@var{name} compiler not installed on this system. +@end smallexample +@end table + +GCC already has an extensive list of suffixes built into it. +This directive will add an entry to the end of the list of suffixes, but +since the list is searched from the end backwards, it is effectively +possible to override earlier entries using this technique. + +@end table + +GCC has the following spec strings built into it. Spec files can +override these strings or create their own. Note that individual +targets can also add their own spec strings to this list. + +@smallexample +asm Options to pass to the assembler +asm_final Options to pass to the assembler post-processor +cpp Options to pass to the C preprocessor +cc1 Options to pass to the C compiler +cc1plus Options to pass to the C++ compiler +endfile Object files to include at the end of the link +link Options to pass to the linker +lib Libraries to include on the command line to the linker +libgcc Decides which GCC support library to pass to the linker +linker Sets the name of the linker +predefines Defines to be passed to the C preprocessor +signed_char Defines to pass to CPP to say whether @code{char} is signed + by default +startfile Object files to include at the start of the link +@end smallexample + +Here is a small example of a spec file: + +@smallexample +%rename lib old_lib + +*lib: +--start-group -lgcc -lc -leval1 --end-group %(old_lib) +@end smallexample + +This example renames the spec called @samp{lib} to @samp{old_lib} and +then overrides the previous definition of @samp{lib} with a new one. +The new definition adds in some extra command-line options before +including the text of the old definition. + +@dfn{Spec strings} are a list of command-line options to be passed to their +corresponding program. In addition, the spec strings can contain +@samp{%}-prefixed sequences to substitute variable text or to +conditionally insert text into the command line. Using these constructs +it is possible to generate quite complex command lines. + +Here is a table of all defined @samp{%}-sequences for spec +strings. Note that spaces are not generated automatically around the +results of expanding these sequences. Therefore you can concatenate them +together or combine them with constant text in a single argument. + +@table @code +@item %% +Substitute one @samp{%} into the program name or argument. + +@item %i +Substitute the name of the input file being processed. + +@item %b +Substitute the basename of the input file being processed. +This is the substring up to (and not including) the last period +and not including the directory. + +@item %B +This is the same as @samp{%b}, but include the file suffix (text after +the last period). + +@item %d +Marks the argument containing or following the @samp{%d} as a +temporary file name, so that that file will be deleted if GCC exits +successfully. Unlike @samp{%g}, this contributes no text to the +argument. + +@item %g@var{suffix} +Substitute a file name that has suffix @var{suffix} and is chosen +once per compilation, and mark the argument in the same way as +@samp{%d}. To reduce exposure to denial-of-service attacks, the file +name is now chosen in a way that is hard to predict even when previously +chosen file names are known. For example, @samp{%g.s @dots{} %g.o @dots{} %g.s} +might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}. @var{suffix} matches +the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is +treated exactly as if @samp{%O} had been preprocessed. Previously, @samp{%g} +was simply substituted with a file name chosen once per compilation, +without regard to any appended suffix (which was therefore treated +just like ordinary text), making such attacks more likely to succeed. + +@item %u@var{suffix} +Like @samp{%g}, but generates a new temporary file name even if +@samp{%u@var{suffix}} was already seen. + +@item %U@var{suffix} +Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a +new one if there is no such last file name. In the absence of any +@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share +the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s} +would involve the generation of two distinct file names, one +for each @samp{%g.s} and another for each @samp{%U.s}. Previously, @samp{%U} was +simply substituted with a file name chosen for the previous @samp{%u}, +without regard to any appended suffix. + +@item %j@var{suffix} +Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is +writable, and if save-temps is off; otherwise, substitute the name +of a temporary file, just like @samp{%u}. This temporary file is not +meant for communication between processes, but rather as a junk +disposal mechanism. + +@item %|@var{suffix} +@itemx %m@var{suffix} +Like @samp{%g}, except if @option{-pipe} is in effect. In that case +@samp{%|} substitutes a single dash and @samp{%m} substitutes nothing at +all. These are the two most common ways to instruct a program that it +should read from standard input or write to standard output. If you +need something more elaborate you can use an @samp{%@{pipe:@code{X}@}} +construct: see for example @file{f/lang-specs.h}. + +@item %.@var{SUFFIX} +Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args +when it is subsequently output with @samp{%*}. @var{SUFFIX} is +terminated by the next space or %. + +@item %w +Marks the argument containing or following the @samp{%w} as the +designated output file of this compilation. This puts the argument +into the sequence of arguments that @samp{%o} will substitute later. + +@item %o +Substitutes the names of all the output files, with spaces +automatically placed around them. You should write spaces +around the @samp{%o} as well or the results are undefined. +@samp{%o} is for use in the specs for running the linker. +Input files whose names have no recognized suffix are not compiled +at all, but they are included among the output files, so they will +be linked. + +@item %O +Substitutes the suffix for object files. Note that this is +handled specially when it immediately follows @samp{%g, %u, or %U}, +because of the need for those to form complete file names. The +handling is such that @samp{%O} is treated exactly as if it had already +been substituted, except that @samp{%g, %u, and %U} do not currently +support additional @var{suffix} characters following @samp{%O} as they would +following, for example, @samp{.o}. + +@item %p +Substitutes the standard macro predefinitions for the +current target machine. Use this when running @code{cpp}. + +@item %P +Like @samp{%p}, but puts @samp{__} before and after the name of each +predefined macro, except for macros that start with @samp{__} or with +@samp{_@var{L}}, where @var{L} is an uppercase letter. This is for ISO +C@. + +@item %I +Substitute any of @option{-iprefix} (made from @env{GCC_EXEC_PREFIX}), +@option{-isysroot} (made from @env{TARGET_SYSTEM_ROOT}), +@option{-isystem} (made from @env{COMPILER_PATH} and @option{-B} options) +and @option{-imultilib} as necessary. + +@item %s +Current argument is the name of a library or startup file of some sort. +Search for that file in a standard list of directories and substitute +the full name found. + +@item %e@var{str} +Print @var{str} as an error message. @var{str} is terminated by a newline. +Use this when inconsistent options are detected. + +@item %(@var{name}) +Substitute the contents of spec string @var{name} at this point. + +@item %[@var{name}] +Like @samp{%(@dots{})} but put @samp{__} around @option{-D} arguments. + +@item %x@{@var{option}@} +Accumulate an option for @samp{%X}. + +@item %X +Output the accumulated linker options specified by @option{-Wl} or a @samp{%x} +spec string. + +@item %Y +Output the accumulated assembler options specified by @option{-Wa}. + +@item %Z +Output the accumulated preprocessor options specified by @option{-Wp}. + +@item %a +Process the @code{asm} spec. This is used to compute the +switches to be passed to the assembler. + +@item %A +Process the @code{asm_final} spec. This is a spec string for +passing switches to an assembler post-processor, if such a program is +needed. + +@item %l +Process the @code{link} spec. This is the spec for computing the +command line passed to the linker. Typically it will make use of the +@samp{%L %G %S %D and %E} sequences. + +@item %D +Dump out a @option{-L} option for each directory that GCC believes might +contain startup files. If the target supports multilibs then the +current multilib directory will be prepended to each of these paths. + +@item %L +Process the @code{lib} spec. This is a spec string for deciding which +libraries should be included on the command line to the linker. + +@item %G +Process the @code{libgcc} spec. This is a spec string for deciding +which GCC support library should be included on the command line to the linker. + +@item %S +Process the @code{startfile} spec. This is a spec for deciding which +object files should be the first ones passed to the linker. Typically +this might be a file named @file{crt0.o}. + +@item %E +Process the @code{endfile} spec. This is a spec string that specifies +the last object files that will be passed to the linker. + +@item %C +Process the @code{cpp} spec. This is used to construct the arguments +to be passed to the C preprocessor. + +@item %1 +Process the @code{cc1} spec. This is used to construct the options to be +passed to the actual C compiler (@samp{cc1}). + +@item %2 +Process the @code{cc1plus} spec. This is used to construct the options to be +passed to the actual C++ compiler (@samp{cc1plus}). + +@item %* +Substitute the variable part of a matched option. See below. +Note that each comma in the substituted string is replaced by +a single space. + +@item %<@code{S} +Remove all occurrences of @code{-S} from the command line. Note---this +command is position dependent. @samp{%} commands in the spec string +before this one will see @code{-S}, @samp{%} commands in the spec string +after this one will not. + +@item %:@var{function}(@var{args}) +Call the named function @var{function}, passing it @var{args}. +@var{args} is first processed as a nested spec string, then split +into an argument vector in the usual fashion. The function returns +a string which is processed as if it had appeared literally as part +of the current spec. + +The following built-in spec functions are provided: + +@table @code +@item @code{if-exists} +The @code{if-exists} spec function takes one argument, an absolute +pathname to a file. If the file exists, @code{if-exists} returns the +pathname. Here is a small example of its usage: + +@smallexample +*startfile: +crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s +@end smallexample + +@item @code{if-exists-else} +The @code{if-exists-else} spec function is similar to the @code{if-exists} +spec function, except that it takes two arguments. The first argument is +an absolute pathname to a file. If the file exists, @code{if-exists-else} +returns the pathname. If it does not exist, it returns the second argument. +This way, @code{if-exists-else} can be used to select one file or another, +based on the existence of the first. Here is a small example of its usage: + +@smallexample +*startfile: +crt0%O%s %:if-exists(crti%O%s) \ +%:if-exists-else(crtbeginT%O%s crtbegin%O%s) +@end smallexample + +@item @code{replace-outfile} +The @code{replace-outfile} spec function takes two arguments. It looks for the +first argument in the outfiles array and replaces it with the second argument. Here +is a small example of its usage: + +@smallexample +%@{fgnu-runtime:%:replace-outfile(-lobjc -lobjc-gnu)@} +@end smallexample + +@end table + +@item %@{@code{S}@} +Substitutes the @code{-S} switch, if that switch was given to GCC@. +If that switch was not specified, this substitutes nothing. Note that +the leading dash is omitted when specifying this option, and it is +automatically inserted if the substitution is performed. Thus the spec +string @samp{%@{foo@}} would match the command-line option @option{-foo} +and would output the command line option @option{-foo}. + +@item %W@{@code{S}@} +Like %@{@code{S}@} but mark last argument supplied within as a file to be +deleted on failure. + +@item %@{@code{S}*@} +Substitutes all the switches specified to GCC whose names start +with @code{-S}, but which also take an argument. This is used for +switches like @option{-o}, @option{-D}, @option{-I}, etc. +GCC considers @option{-o foo} as being +one switch whose names starts with @samp{o}. %@{o*@} would substitute this +text, including the space. Thus two arguments would be generated. + +@item %@{@code{S}*&@code{T}*@} +Like %@{@code{S}*@}, but preserve order of @code{S} and @code{T} options +(the order of @code{S} and @code{T} in the spec is not significant). +There can be any number of ampersand-separated variables; for each the +wild card is optional. Useful for CPP as @samp{%@{D*&U*&A*@}}. + +@item %@{@code{S}:@code{X}@} +Substitutes @code{X}, if the @samp{-S} switch was given to GCC@. + +@item %@{!@code{S}:@code{X}@} +Substitutes @code{X}, if the @samp{-S} switch was @emph{not} given to GCC@. + +@item %@{@code{S}*:@code{X}@} +Substitutes @code{X} if one or more switches whose names start with +@code{-S} are specified to GCC@. Normally @code{X} is substituted only +once, no matter how many such switches appeared. However, if @code{%*} +appears somewhere in @code{X}, then @code{X} will be substituted once +for each matching switch, with the @code{%*} replaced by the part of +that switch that matched the @code{*}. + +@item %@{.@code{S}:@code{X}@} +Substitutes @code{X}, if processing a file with suffix @code{S}. + +@item %@{!.@code{S}:@code{X}@} +Substitutes @code{X}, if @emph{not} processing a file with suffix @code{S}. + +@c APPLE LOCAL begin mainline 2007-03-13 5040758 +@item %@{,@code{S}:@code{X}@} +Substitutes @code{X}, if processing a file for language @code{S}. + +@item %@{!,@code{S}:@code{X}@} +Substitutes @code{X}, if not processing a file for language @code{S}. + +@item %@{@code{S}|@code{P}:@code{X}@} +Substitutes @code{X} if either @code{-S} or @code{-P} was given to +GCC@. This may be combined with @samp{!}, @samp{.}, @samp{,}, and +@code{*} sequences as well, although they have a stronger binding than +the @samp{|}. If @code{%*} appears in @code{X}, all of the +alternatives must be starred, and only the first matching alternative +is substituted. + +@c APPLE LOCAL end mainline 2007-03-13 5040758 +For example, a spec string like this: + +@smallexample +%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@} +@end smallexample + +will output the following command-line options from the following input +command-line options: + +@smallexample +fred.c -foo -baz +jim.d -bar -boggle +-d fred.c -foo -baz -boggle +-d jim.d -bar -baz -boggle +@end smallexample + +@item %@{S:X; T:Y; :D@} + +@c APPLE LOCAL begin mainline 2007-03-13 5040758 +If @code{S} was given to GCC, substitutes @code{X}; else if @code{T} was +given to GCC, substitutes @code{Y}; else substitutes @code{D}. There can +be as many clauses as you need. This may be combined with @code{.}, +@code{,}, @code{!}, @code{|}, and @code{*} as needed. +@c APPLE LOCAL end mainline 2007-03-13 5040758 + + +@end table + +The conditional text @code{X} in a %@{@code{S}:@code{X}@} or similar +construct may contain other nested @samp{%} constructs or spaces, or +even newlines. They are processed as usual, as described above. +Trailing white space in @code{X} is ignored. White space may also +appear anywhere on the left side of the colon in these constructs, +except between @code{.} or @code{*} and the corresponding word. + +The @option{-O}, @option{-f}, @option{-m}, and @option{-W} switches are +handled specifically in these constructs. If another value of +@option{-O} or the negated form of a @option{-f}, @option{-m}, or +@option{-W} switch is found later in the command line, the earlier +switch value is ignored, except with @{@code{S}*@} where @code{S} is +just one letter, which passes all matching options. + +The character @samp{|} at the beginning of the predicate text is used to +indicate that a command should be piped to the following command, but +only if @option{-pipe} is specified. + +It is built into GCC which switches take arguments and which do not. +(You might think it would be useful to generalize this to allow each +compiler's spec to say which switches take arguments. But this cannot +be done in a consistent fashion. GCC cannot even decide which input +files have been specified without knowing which switches take arguments, +and it must know which input files to compile in order to tell which +compilers to run). + +GCC also knows implicitly that arguments starting in @option{-l} are to be +treated as compiler output files, and passed to the linker in their +proper position among the other output files. + +@c man begin OPTIONS + +@node Target Options +@section Specifying Target Machine and Compiler Version +@cindex target options +@cindex cross compiling +@cindex specifying machine version +@cindex specifying compiler version and target machine +@cindex compiler version, specifying +@cindex target machine, specifying + +The usual way to run GCC is to run the executable called @file{gcc}, or +@file{<machine>-gcc} when cross-compiling, or +@file{<machine>-gcc-<version>} to run a version other than the one that +was installed last. Sometimes this is inconvenient, so GCC provides +options that will switch to another cross-compiler or version. + +@table @gcctabopt +@item -b @var{machine} +@opindex b +The argument @var{machine} specifies the target machine for compilation. + +The value to use for @var{machine} is the same as was specified as the +machine type when configuring GCC as a cross-compiler. For +example, if a cross-compiler was configured with @samp{configure +arm-elf}, meaning to compile for an arm processor with elf binaries, +then you would specify @option{-b arm-elf} to run that cross compiler. +Because there are other options beginning with @option{-b}, the +configuration must contain a hyphen. + +@item -V @var{version} +@opindex V +The argument @var{version} specifies which version of GCC to run. +This is useful when multiple versions are installed. For example, +@var{version} might be @samp{4.0}, meaning to run GCC version 4.0. +@end table + +The @option{-V} and @option{-b} options work by running the +@file{<machine>-gcc-<version>} executable, so there's no real reason to +use them if you can just run that directly. + +@node Submodel Options +@section Hardware Models and Configurations +@cindex submodel options +@cindex specifying hardware config +@cindex hardware models and configurations, specifying +@cindex machine dependent options + +Earlier we discussed the standard option @option{-b} which chooses among +different installed compilers for completely different target +machines, such as VAX vs.@: 68000 vs.@: 80386. + +In addition, each of these target machine types can have its own +special options, starting with @samp{-m}, to choose among various +hardware models or configurations---for example, 68010 vs 68020, +floating coprocessor or none. A single installed version of the +compiler can compile for any model or configuration, according to the +options specified. + +Some configurations of the compiler also support additional special +options, usually for compatibility with other compilers on the same +platform. + +@c This list is ordered alphanumerically by subsection name. +@c It should be the same order and spelling as these options are listed +@c in Machine Dependent Options + +@menu +@c APPLE LOCAL prune man page +@ignore +* ARC Options:: +@c APPLE LOCAL ARM prune man page +@end ignore +* ARM Options:: +@c APPLE LOCAL ARM prune man page +@ignore +* AVR Options:: +* Blackfin Options:: +* CRIS Options:: +* CRX Options:: +@c APPLE LOCAL prune man page +@end ignore +* Darwin Options:: +@c APPLE LOCAL prune man page +@ignore +* DEC Alpha Options:: +* DEC Alpha/VMS Options:: +* FRV Options:: +* GNU/Linux Options:: +* H8/300 Options:: +* HPPA Options:: +@c APPLE LOCAL prune man page +@end ignore +* i386 and x86-64 Options:: +@c APPLE LOCAL prune man page +@ignore +* IA-64 Options:: +* M32C Options:: +* M32R/D Options:: +* M680x0 Options:: +* M68hc1x Options:: +* MCore Options:: +* MIPS Options:: +* MMIX Options:: +* MN10300 Options:: +* MT Options:: +* PDP-11 Options:: +@c APPLE LOCAL prune man page +@end ignore +* PowerPC Options:: +* RS/6000 and PowerPC Options:: +@c APPLE LOCAL prune man page +@ignore +* S/390 and zSeries Options:: +* Score Options:: +* SH Options:: +* SPARC Options:: +* System V Options:: +* TMS320C3x/C4x Options:: +* V850 Options:: +* VAX Options:: +* x86-64 Options:: +* Xstormy16 Options:: +* Xtensa Options:: +* zSeries Options:: +@c APPLE LOCAL prune man page +@end ignore +@end menu + +@c APPLE LOCAL prune man page +@ignore +@node ARC Options +@subsection ARC Options +@cindex ARC Options + +These options are defined for ARC implementations: + +@table @gcctabopt +@item -EL +@opindex EL +Compile code for little endian mode. This is the default. + +@item -EB +@opindex EB +Compile code for big endian mode. + +@item -mmangle-cpu +@opindex mmangle-cpu +Prepend the name of the cpu to all public symbol names. +In multiple-processor systems, there are many ARC variants with different +instruction and register set characteristics. This flag prevents code +compiled for one cpu to be linked with code compiled for another. +No facility exists for handling variants that are ``almost identical''. +This is an all or nothing option. + +@item -mcpu=@var{cpu} +@opindex mcpu +Compile code for ARC variant @var{cpu}. +Which variants are supported depend on the configuration. +All variants support @option{-mcpu=base}, this is the default. + +@item -mtext=@var{text-section} +@itemx -mdata=@var{data-section} +@itemx -mrodata=@var{readonly-data-section} +@opindex mtext +@opindex mdata +@opindex mrodata +Put functions, data, and readonly data in @var{text-section}, +@var{data-section}, and @var{readonly-data-section} respectively +by default. This can be overridden with the @code{section} attribute. +@xref{Variable Attributes}. + +@end table +@c APPLE LOCAL ARM prune man page +@end ignore + +@node ARM Options +@subsection ARM Options +@cindex ARM options + +These @samp{-m} options are defined for Advanced RISC Machines (ARM) +architectures: + +@table @gcctabopt +@item -mabi=@var{name} +@opindex mabi +Generate code for the specified ABI@. Permissible values are: @samp{apcs-gnu}, +@samp{atpcs}, @samp{aapcs}, @samp{aapcs-linux} and @samp{iwmmxt}. + +@item -mapcs-frame +@opindex mapcs-frame +Generate a stack frame that is compliant with the ARM Procedure Call +Standard for all functions, even if this is not strictly necessary for +correct execution of the code. Specifying @option{-fomit-frame-pointer} +with this option will cause the stack frames not to be generated for +leaf functions. The default is @option{-mno-apcs-frame}. + +@item -mapcs +@opindex mapcs +This is a synonym for @option{-mapcs-frame}. + +@c APPLE LOCAL We already have ignore running -- do not do this one --bowdidge +@c @ignore +@c not currently implemented +@item -mapcs-stack-check +@opindex mapcs-stack-check +Generate code to check the amount of stack space available upon entry to +every function (that actually uses some stack space). If there is +insufficient space available then either the function +@samp{__rt_stkovf_split_small} or @samp{__rt_stkovf_split_big} will be +called, depending upon the amount of stack space required. The run time +system is required to provide these functions. The default is +@option{-mno-apcs-stack-check}, since this produces smaller code. + +@c not currently implemented +@item -mapcs-float +@opindex mapcs-float +Pass floating point arguments using the float point registers. This is +one of the variants of the APCS@. This option is recommended if the +target hardware has a floating point unit or if a lot of floating point +arithmetic is going to be performed by the code. The default is +@option{-mno-apcs-float}, since integer only code is slightly increased in +size if @option{-mapcs-float} is used. + +@c not currently implemented +@item -mapcs-reentrant +@opindex mapcs-reentrant +Generate reentrant, position independent code. The default is +@option{-mno-apcs-reentrant}. +@c APPLE LOCAL We already have ignore running -- do not do this one --bowdidge +@c @end ignore + +@item -mthumb-interwork +@opindex mthumb-interwork +Generate code which supports calling between the ARM and Thumb +instruction sets. Without this option the two instruction sets cannot +be reliably used inside one program. The default is +@option{-mno-thumb-interwork}, since slightly larger code is generated +when @option{-mthumb-interwork} is specified. + +@item -mno-sched-prolog +@opindex mno-sched-prolog +Prevent the reordering of instructions in the function prolog, or the +merging of those instruction with the instructions in the function's +body. This means that all functions will start with a recognizable set +of instructions (or in fact one of a choice from a small set of +different function prologues), and this information can be used to +locate the start if functions inside an executable piece of code. The +default is @option{-msched-prolog}. + +@item -mhard-float +@opindex mhard-float +Generate output containing floating point instructions. This is the +default. + +@item -msoft-float +@opindex msoft-float +Generate output containing library calls for floating point. +@strong{Warning:} the requisite libraries are not available for all ARM +targets. Normally the facilities of the machine's usual C compiler are +used, but this cannot be done directly in cross-compilation. You must make +your own arrangements to provide suitable library functions for +cross-compilation. + +@option{-msoft-float} changes the calling convention in the output file; +therefore, it is only useful if you compile @emph{all} of a program with +this option. In particular, you need to compile @file{libgcc.a}, the +library that comes with GCC, with @option{-msoft-float} in order for +this to work. + +@item -mfloat-abi=@var{name} +@opindex mfloat-abi +Specifies which ABI to use for floating point values. Permissible values +are: @samp{soft}, @samp{softfp} and @samp{hard}. + +@samp{soft} and @samp{hard} are equivalent to @option{-msoft-float} +and @option{-mhard-float} respectively. @samp{softfp} allows the generation +of floating point instructions, but still uses the soft-float calling +conventions. + +@item -mlittle-endian +@opindex mlittle-endian +Generate code for a processor running in little-endian mode. This is +the default for all standard configurations. + +@item -mbig-endian +@opindex mbig-endian +Generate code for a processor running in big-endian mode; the default is +to compile code for a little-endian processor. + +@item -mwords-little-endian +@opindex mwords-little-endian +This option only applies when generating code for big-endian processors. +Generate code for a little-endian word order but a big-endian byte +order. That is, a byte order of the form @samp{32107654}. Note: this +option should only be used if you require compatibility with code for +big-endian ARM processors generated by versions of the compiler prior to +2.8. + +@item -mcpu=@var{name} +@opindex mcpu +This specifies the name of the target ARM processor. GCC uses this name +to determine what kind of instructions it can emit when generating +assembly code. Permissible names are: @samp{arm2}, @samp{arm250}, +@samp{arm3}, @samp{arm6}, @samp{arm60}, @samp{arm600}, @samp{arm610}, +@samp{arm620}, @samp{arm7}, @samp{arm7m}, @samp{arm7d}, @samp{arm7dm}, +@samp{arm7di}, @samp{arm7dmi}, @samp{arm70}, @samp{arm700}, +@samp{arm700i}, @samp{arm710}, @samp{arm710c}, @samp{arm7100}, +@samp{arm7500}, @samp{arm7500fe}, @samp{arm7tdmi}, @samp{arm7tdmi-s}, +@samp{arm8}, @samp{strongarm}, @samp{strongarm110}, @samp{strongarm1100}, +@samp{arm8}, @samp{arm810}, @samp{arm9}, @samp{arm9e}, @samp{arm920}, +@samp{arm920t}, @samp{arm922t}, @samp{arm946e-s}, @samp{arm966e-s}, +@samp{arm968e-s}, @samp{arm926ej-s}, @samp{arm940t}, @samp{arm9tdmi}, +@samp{arm10tdmi}, @samp{arm1020t}, @samp{arm1026ej-s}, +@samp{arm10e}, @samp{arm1020e}, @samp{arm1022e}, +@samp{arm1136j-s}, @samp{arm1136jf-s}, @samp{mpcore}, @samp{mpcorenovfp}, +@samp{arm1176jz-s}, @samp{arm1176jzf-s}, @samp{xscale}, @samp{iwmmxt}, +@samp{ep9312}. + +@itemx -mtune=@var{name} +@opindex mtune +This option is very similar to the @option{-mcpu=} option, except that +instead of specifying the actual target processor type, and hence +restricting which instructions can be used, it specifies that GCC should +tune the performance of the code as if the target were of the type +specified in this option, but still choosing the instructions that it +will generate based on the cpu specified by a @option{-mcpu=} option. +For some ARM implementations better performance can be obtained by using +this option. + +@item -march=@var{name} +@opindex march +This specifies the name of the target ARM architecture. GCC uses this +name to determine what kind of instructions it can emit when generating +assembly code. This option can be used in conjunction with or instead +of the @option{-mcpu=} option. Permissible names are: @samp{armv2}, +@samp{armv2a}, @samp{armv3}, @samp{armv3m}, @samp{armv4}, @samp{armv4t}, +@samp{armv5}, @samp{armv5t}, @samp{armv5te}, @samp{armv6}, @samp{armv6j}, +@samp{iwmmxt}, @samp{ep9312}. + +@item -mfpu=@var{name} +@itemx -mfpe=@var{number} +@itemx -mfp=@var{number} +@opindex mfpu +@opindex mfpe +@opindex mfp +This specifies what floating point hardware (or hardware emulation) is +available on the target. Permissible names are: @samp{fpa}, @samp{fpe2}, +@samp{fpe3}, @samp{maverick}, @samp{vfp}. @option{-mfp} and @option{-mfpe} +are synonyms for @option{-mfpu}=@samp{fpe}@var{number}, for compatibility +with older versions of GCC@. + +If @option{-msoft-float} is specified this specifies the format of +floating point values. + +@item -mstructure-size-boundary=@var{n} +@opindex mstructure-size-boundary +The size of all structures and unions will be rounded up to a multiple +of the number of bits set by this option. Permissible values are 8, 32 +and 64. The default value varies for different toolchains. For the COFF +targeted toolchain the default value is 8. A value of 64 is only allowed +if the underlying ABI supports it. + +Specifying the larger number can produce faster, more efficient code, but +can also increase the size of the program. Different values are potentially +incompatible. Code compiled with one value cannot necessarily expect to +work with code or libraries compiled with another value, if they exchange +information using structures or unions. + +@item -mabort-on-noreturn +@opindex mabort-on-noreturn +Generate a call to the function @code{abort} at the end of a +@code{noreturn} function. It will be executed if the function tries to +return. + +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Tells the compiler to perform function calls by first loading the +address of the function into a register and then performing a subroutine +call on this register. This switch is needed if the target function +will lie outside of the 64 megabyte addressing range of the offset based +version of subroutine call instruction. + +Even if this switch is enabled, not all function calls will be turned +into long calls. The heuristic is that static functions, functions +which have the @samp{short-call} attribute, functions that are inside +the scope of a @samp{#pragma no_long_calls} directive and functions whose +definitions have already been compiled within the current compilation +unit, will not be turned into long calls. The exception to this rule is +that weak function definitions, functions with the @samp{long-call} +attribute or the @samp{section} attribute, and functions that are within +the scope of a @samp{#pragma long_calls} directive, will always be +turned into long calls. + +This feature is not enabled by default. Specifying +@option{-mno-long-calls} will restore the default behavior, as will +placing the function calls within the scope of a @samp{#pragma +long_calls_off} directive. Note these switches have no effect on how +the compiler generates code to handle function calls via function +pointers. + +@item -mnop-fun-dllimport +@opindex mnop-fun-dllimport +Disable support for the @code{dllimport} attribute. + +@item -msingle-pic-base +@opindex msingle-pic-base +Treat the register used for PIC addressing as read-only, rather than +loading it in the prologue for each function. The run-time system is +responsible for initializing this register with an appropriate value +before execution begins. + +@item -mpic-register=@var{reg} +@opindex mpic-register +Specify the register to be used for PIC addressing. The default is R10 +unless stack-checking is enabled, when R9 is used. + +@item -mcirrus-fix-invalid-insns +@opindex mcirrus-fix-invalid-insns +@opindex mno-cirrus-fix-invalid-insns +Insert NOPs into the instruction stream to in order to work around +problems with invalid Maverick instruction combinations. This option +is only valid if the @option{-mcpu=ep9312} option has been used to +enable generation of instructions for the Cirrus Maverick floating +point co-processor. This option is not enabled by default, since the +problem is only present in older Maverick implementations. The default +can be re-enabled by use of the @option{-mno-cirrus-fix-invalid-insns} +switch. + +@item -mpoke-function-name +@opindex mpoke-function-name +Write the name of each function into the text section, directly +preceding the function prologue. The generated code is similar to this: + +@smallexample + t0 + .ascii "arm_poke_function_name", 0 + .align + t1 + .word 0xff000000 + (t1 - t0) + arm_poke_function_name + mov ip, sp + stmfd sp!, @{fp, ip, lr, pc@} + sub fp, ip, #4 +@end smallexample + +When performing a stack backtrace, code can inspect the value of +@code{pc} stored at @code{fp + 0}. If the trace function then looks at +location @code{pc - 12} and the top 8 bits are set, then we know that +there is a function name embedded immediately preceding this location +and has length @code{((pc[-3]) & 0xff000000)}. + +@c APPLE LOCAL begin v7 thumb is default +@item -mthumb +@opindex mthumb +Generate code for the 16-bit Thumb instruction set. For ARMv7, the default +is to use the THUMB2 instruction set. For all other architectures, the default +is to use the 32-bit ARM instruction set. The ARM instruction set may be +explicitly selected via @option{-mno-thumb} or @option{-marm}. +@c APPLE LOCAL end v7 thumb is default + +@item -mtpcs-frame +@opindex mtpcs-frame +Generate a stack frame that is compliant with the Thumb Procedure Call +Standard for all non-leaf functions. (A leaf function is one that does +not call any other functions.) The default is @option{-mno-tpcs-frame}. + +@item -mtpcs-leaf-frame +@opindex mtpcs-leaf-frame +Generate a stack frame that is compliant with the Thumb Procedure Call +Standard for all leaf functions. (A leaf function is one that does +not call any other functions.) The default is @option{-mno-apcs-leaf-frame}. + +@item -mcallee-super-interworking +@opindex mcallee-super-interworking +Gives all externally visible functions in the file being compiled an ARM +instruction set header which switches to Thumb mode before executing the +rest of the function. This allows these functions to be called from +non-interworking code. + +@item -mcaller-super-interworking +@opindex mcaller-super-interworking +Allows calls via function pointers (including virtual functions) to +execute correctly regardless of whether the target code has been +compiled for interworking or not. There is a small overhead in the cost +of executing a function pointer if this option is enabled. + +@item -mtp=@var{name} +@opindex mtp +Specify the access model for the thread local storage pointer. The valid +models are @option{soft}, which generates calls to @code{__aeabi_read_tp}, +@option{cp15}, which fetches the thread pointer from @code{cp15} directly +(supported in the arm6k architecture), and @option{auto}, which uses the +best available method for the selected processor. The default setting is +@option{auto}. + +@c APPLE LOCAL begin 5946347 ms_struct support +@item -mms-bitfields +@opindex mms-bitfields +Set the default structure layout to be compatible with the Microsoft +compiler standard. This is equivalent to adding an @code{ms_struct} +attribute to each structure and union tag definition. The default is +@option{mno-ms-bitfields}. +@c APPLE LOCAL end 5946347 ms_struct support + +@end table + +@c APPLE LOCAL ARM prune man page +@ignore +@node AVR Options +@subsection AVR Options +@cindex AVR Options + +These options are defined for AVR implementations: + +@table @gcctabopt +@item -mmcu=@var{mcu} +@opindex mmcu +Specify ATMEL AVR instruction set or MCU type. + +Instruction set avr1 is for the minimal AVR core, not supported by the C +compiler, only for assembler programs (MCU types: at90s1200, attiny10, +attiny11, attiny12, attiny15, attiny28). + +Instruction set avr2 (default) is for the classic AVR core with up to +8K program memory space (MCU types: at90s2313, at90s2323, attiny22, +at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515, +at90c8534, at90s8535). + +Instruction set avr3 is for the classic AVR core with up to 128K program +memory space (MCU types: atmega103, atmega603, at43usb320, at76c711). + +Instruction set avr4 is for the enhanced AVR core with up to 8K program +memory space (MCU types: atmega8, atmega83, atmega85). + +Instruction set avr5 is for the enhanced AVR core with up to 128K program +memory space (MCU types: atmega16, atmega161, atmega163, atmega32, atmega323, +atmega64, atmega128, at43usb355, at94k). + +@item -msize +@opindex msize +Output instruction sizes to the asm file. + +@item -minit-stack=@var{N} +@opindex minit-stack +Specify the initial stack address, which may be a symbol or numeric value, +@samp{__stack} is the default. + +@item -mno-interrupts +@opindex mno-interrupts +Generated code is not compatible with hardware interrupts. +Code size will be smaller. + +@item -mcall-prologues +@opindex mcall-prologues +Functions prologues/epilogues expanded as call to appropriate +subroutines. Code size will be smaller. + +@item -mno-tablejump +@opindex mno-tablejump +Do not generate tablejump insns which sometimes increase code size. + +@item -mtiny-stack +@opindex mtiny-stack +Change only the low 8 bits of the stack pointer. + +@item -mint8 +@opindex mint8 +Assume int to be 8 bit integer. This affects the sizes of all types: A +char will be 1 byte, an int will be 1 byte, an long will be 2 bytes +and long long will be 4 bytes. Please note that this option does not +comply to the C standards, but it will provide you with smaller code +size. +@end table + +@node Blackfin Options +@subsection Blackfin Options +@cindex Blackfin Options + +@table @gcctabopt +@item -momit-leaf-frame-pointer +@opindex momit-leaf-frame-pointer +Don't keep the frame pointer in a register for leaf functions. This +avoids the instructions to save, set up and restore frame pointers and +makes an extra register available in leaf functions. The option +@option{-fomit-frame-pointer} removes the frame pointer for all functions +which might make debugging harder. + +@item -mspecld-anomaly +@opindex mspecld-anomaly +When enabled, the compiler will ensure that the generated code does not +contain speculative loads after jump instructions. This option is enabled +by default. + +@item -mno-specld-anomaly +@opindex mno-specld-anomaly +Don't generate extra code to prevent speculative loads from occurring. + +@item -mcsync-anomaly +@opindex mcsync-anomaly +When enabled, the compiler will ensure that the generated code does not +contain CSYNC or SSYNC instructions too soon after conditional branches. +This option is enabled by default. + +@item -mno-csync-anomaly +@opindex mno-csync-anomaly +Don't generate extra code to prevent CSYNC or SSYNC instructions from +occurring too soon after a conditional branch. + +@item -mlow-64k +@opindex mlow-64k +When enabled, the compiler is free to take advantage of the knowledge that +the entire program fits into the low 64k of memory. + +@item -mno-low-64k +@opindex mno-low-64k +Assume that the program is arbitrarily large. This is the default. + +@item -mid-shared-library +@opindex mid-shared-library +Generate code that supports shared libraries via the library ID method. +This allows for execute in place and shared libraries in an environment +without virtual memory management. This option implies @option{-fPIC}. + +@item -mno-id-shared-library +@opindex mno-id-shared-library +Generate code that doesn't assume ID based shared libraries are being used. +This is the default. + +@item -mshared-library-id=n +@opindex mshared-library-id +Specified the identification number of the ID based shared library being +compiled. Specifying a value of 0 will generate more compact code, specifying +other values will force the allocation of that number to the current +library but is no more space or time efficient than omitting this option. + +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Tells the compiler to perform function calls by first loading the +address of the function into a register and then performing a subroutine +call on this register. This switch is needed if the target function +will lie outside of the 24 bit addressing range of the offset based +version of subroutine call instruction. + +This feature is not enabled by default. Specifying +@option{-mno-long-calls} will restore the default behavior. Note these +switches have no effect on how the compiler generates code to handle +function calls via function pointers. +@end table + +@node CRIS Options +@subsection CRIS Options +@cindex CRIS Options + +These options are defined specifically for the CRIS ports. + +@table @gcctabopt +@item -march=@var{architecture-type} +@itemx -mcpu=@var{architecture-type} +@opindex march +@opindex mcpu +Generate code for the specified architecture. The choices for +@var{architecture-type} are @samp{v3}, @samp{v8} and @samp{v10} for +respectively ETRAX@w{ }4, ETRAX@w{ }100, and ETRAX@w{ }100@w{ }LX@. +Default is @samp{v0} except for cris-axis-linux-gnu, where the default is +@samp{v10}. + +@item -mtune=@var{architecture-type} +@opindex mtune +Tune to @var{architecture-type} everything applicable about the generated +code, except for the ABI and the set of available instructions. The +choices for @var{architecture-type} are the same as for +@option{-march=@var{architecture-type}}. + +@item -mmax-stack-frame=@var{n} +@opindex mmax-stack-frame +Warn when the stack frame of a function exceeds @var{n} bytes. + +@item -melinux-stacksize=@var{n} +@opindex melinux-stacksize +Only available with the @samp{cris-axis-aout} target. Arranges for +indications in the program to the kernel loader that the stack of the +program should be set to @var{n} bytes. + +@item -metrax4 +@itemx -metrax100 +@opindex metrax4 +@opindex metrax100 +The options @option{-metrax4} and @option{-metrax100} are synonyms for +@option{-march=v3} and @option{-march=v8} respectively. + +@item -mmul-bug-workaround +@itemx -mno-mul-bug-workaround +@opindex mmul-bug-workaround +@opindex mno-mul-bug-workaround +Work around a bug in the @code{muls} and @code{mulu} instructions for CPU +models where it applies. This option is active by default. + +@item -mpdebug +@opindex mpdebug +Enable CRIS-specific verbose debug-related information in the assembly +code. This option also has the effect to turn off the @samp{#NO_APP} +formatted-code indicator to the assembler at the beginning of the +assembly file. + +@item -mcc-init +@opindex mcc-init +Do not use condition-code results from previous instruction; always emit +compare and test instructions before use of condition codes. + +@item -mno-side-effects +@opindex mno-side-effects +Do not emit instructions with side-effects in addressing modes other than +post-increment. + +@item -mstack-align +@itemx -mno-stack-align +@itemx -mdata-align +@itemx -mno-data-align +@itemx -mconst-align +@itemx -mno-const-align +@opindex mstack-align +@opindex mno-stack-align +@opindex mdata-align +@opindex mno-data-align +@opindex mconst-align +@opindex mno-const-align +These options (no-options) arranges (eliminate arrangements) for the +stack-frame, individual data and constants to be aligned for the maximum +single data access size for the chosen CPU model. The default is to +arrange for 32-bit alignment. ABI details such as structure layout are +not affected by these options. + +@item -m32-bit +@itemx -m16-bit +@itemx -m8-bit +@opindex m32-bit +@opindex m16-bit +@opindex m8-bit +Similar to the stack- data- and const-align options above, these options +arrange for stack-frame, writable data and constants to all be 32-bit, +16-bit or 8-bit aligned. The default is 32-bit alignment. + +@item -mno-prologue-epilogue +@itemx -mprologue-epilogue +@opindex mno-prologue-epilogue +@opindex mprologue-epilogue +With @option{-mno-prologue-epilogue}, the normal function prologue and +epilogue that sets up the stack-frame are omitted and no return +instructions or return sequences are generated in the code. Use this +option only together with visual inspection of the compiled code: no +warnings or errors are generated when call-saved registers must be saved, +or storage for local variable needs to be allocated. + +@item -mno-gotplt +@itemx -mgotplt +@opindex mno-gotplt +@opindex mgotplt +With @option{-fpic} and @option{-fPIC}, don't generate (do generate) +instruction sequences that load addresses for functions from the PLT part +of the GOT rather than (traditional on other architectures) calls to the +PLT@. The default is @option{-mgotplt}. + +@item -maout +@opindex maout +Legacy no-op option only recognized with the cris-axis-aout target. + +@item -melf +@opindex melf +Legacy no-op option only recognized with the cris-axis-elf and +cris-axis-linux-gnu targets. + +@item -melinux +@opindex melinux +Only recognized with the cris-axis-aout target, where it selects a +GNU/linux-like multilib, include files and instruction set for +@option{-march=v8}. + +@item -mlinux +@opindex mlinux +Legacy no-op option only recognized with the cris-axis-linux-gnu target. + +@item -sim +@opindex sim +This option, recognized for the cris-axis-aout and cris-axis-elf arranges +to link with input-output functions from a simulator library. Code, +initialized data and zero-initialized data are allocated consecutively. + +@item -sim2 +@opindex sim2 +Like @option{-sim}, but pass linker options to locate initialized data at +0x40000000 and zero-initialized data at 0x80000000. +@end table + +@node CRX Options +@subsection CRX Options +@cindex CRX Options + +These options are defined specifically for the CRX ports. + +@table @gcctabopt + +@item -mmac +@opindex mmac +Enable the use of multiply-accumulate instructions. Disabled by default. + +@item -mpush-args +@opindex mpush-args +Push instructions will be used to pass outgoing arguments when functions +are called. Enabled by default. +@end table +@c APPLE LOCAL prune man page +@end ignore + +@node Darwin Options +@subsection Darwin Options +@cindex Darwin options + +These options are defined for all architectures running the Darwin operating +system. + +@c APPLE LOCAL universal +FSF GCC on Darwin does not create ``universal'' object files; it will create +an object file for the single architecture that it was built to +@c APPLE LOCAL universal +target. Apple's GCC on Darwin does create ``universal'' files if multiple +@option{-arch} options are used; it does so by running the compiler or +linker multiple times and joining the results together with +@file{lipo}. + +The subtype of the file created (like @samp{ppc7400} or @samp{ppc970} or +@samp{i686}) is determined by the flags that specify the ISA +that GCC is targetting, like @option{-mcpu} or @option{-march}. The +@option{-force_cpusubtype_ALL} option can be used to override this. + +The Darwin tools vary in their behavior when presented with an ISA +mismatch. The assembler, @file{as}, will only permit instructions to +be used that are valid for the subtype of the file it is generating, +so you cannot put 64-bit instructions in an @samp{ppc750} object file. +The linker for shared libraries, @file{/usr/bin/libtool}, will fail +and print an error if asked to create a shared library with a less +restrictive subtype than its input files (for instance, trying to put +a @samp{ppc970} object file in a @samp{ppc7400} library). The linker +for executables, @file{ld}, will quietly give the executable the most +restrictive subtype of any of its input files. + +@table @gcctabopt +@item -F@var{dir} +@opindex F +Add the framework directory @var{dir} to the head of the list of +directories to be searched for header files. These directories are +interleaved with those specified by @option{-I} options and are +scanned in a left-to-right order. + +A framework directory is a directory with frameworks in it. A +framework is a directory with a @samp{"Headers"} and/or +@samp{"PrivateHeaders"} directory contained directly in it that ends +in @samp{".framework"}. The name of a framework is the name of this +directory excluding the @samp{".framework"}. Headers associated with +the framework are found in one of those two directories, with +@samp{"Headers"} being searched first. A subframework is a framework +directory that is in a framework's @samp{"Frameworks"} directory. +Includes of subframework headers can only appear in a header of a +framework that contains the subframework, or in a sibling subframework +header. Two subframeworks are siblings if they occur in the same +framework. A subframework should not have the same name as a +framework, a warning will be issued if this is violated. Currently a +subframework cannot have subframeworks, in the future, the mechanism +may be extended to support this. The standard frameworks can be found +in @samp{"/System/Library/Frameworks"} and +@samp{"/Library/Frameworks"}. An example include looks like +@code{#include <Framework/header.h>}, where @samp{Framework} denotes +the name of the framework and header.h is found in the +@samp{"PrivateHeaders"} or @samp{"Headers"} directory. + +@c APPLE LOCAL begin iframework for 4.3 4094959 +@item -iframework@var{dir} +@opindex iframework +Like @option{-F} except the directory is a treated as a system +directory. The main effect is to not warn about constructs contained +within header files found via @var{dir}. +@c APPLE LOCAL end iframework for 4.3 4094959 + +@item -gused +@opindex gused +Emit debugging information for symbols that are used. For STABS +debugging format, this enables @option{-feliminate-unused-debug-symbols}. +This is by default ON@. + +@item -gfull +@opindex gfull +Emit debugging information for all symbols and types. + +@item -mmacosx-version-min=@var{version} +The earliest version of MacOS X that this executable will run on +is @var{version}. Typical values of @var{version} include @code{10.1}, +@code{10.2}, and @code{10.3.9}. + +@c APPLE LOCAL begin ARM 5905142 +This value can also be set with the @env{MACOSX_DEPLOYMENT_TARGET} +environment variable. If both the command-line option is specified +and the environment variable is set, the command-line option will +take precedence. +@c APPLE LOCAL end ARM 5905142 + +@c APPLE LOCAL begin mainline 2007-06-14 5235474 +If the compiler was built to use the system's headers by default, +then the default for this option is the system version on which the +compiler is running, otherwise the default is to make choices which +are compatible with as many systems and code bases as possible. +@c APPLE LOCAL end mainline 2007-06-14 5235474 + +@c APPLE LOCAL begin ARM 5905142 +This value is not set by default for ARM targets. + +@item -miphoneos-version-min=@var{version} +The earliest version of iPhone OS that this executable will run on +is @var{version}. + +This value can also be set with the @env{IPHONEOS_DEPLOYMENT_TARGET} +environment variable. If both the command-line option is specified +and the environment variable is set, the command-line option will +take precedence. + +On ARM targets, if not specified by the command-line option or +environment variable, this value defaults to 2.0. +@c APPLE LOCAL end ARM 5905142 + +@item -mkernel +@opindex mkernel +Enable kernel development mode. The @option{-mkernel} option sets +@c APPLE LOCAL 5731065 +@option{-static}, @option{-fno-common}, @option{-fno-builtin}, @option{-fno-cxa-atexit}, +@c APPLE LOCAL 5628030 +@option{-fno-exceptions}, @option{-fno-non-call-exceptions}, @option{-fno-asynchronous-unwind-tables}, +@option{-fapple-kext}, @option{-fno-weak} and @option{-fno-rtti} where +applicable. This mode also sets @option{-mno-altivec}, +@c APPLE LOCAL begin 5731065 6268204 +@option{-msoft-float} and @option{-mlong-branch} for PowerPC targets, +@option{-mno-red-zone} on x86_64, and @option{-mlong-branch} for ARM +targets. Of these, only -msoft-float can be changed which is useful in +a kext that wishes to use the hardware floating point unit. +@c APPLE LOCAL end 5731065 6268204 +@c APPLE LOCAL begin kext weak_import 5935650 +@option{-dynamic} can be used to override the effects of -static on +the assembler to enable the use of weak_import. +@c APPLE LOCAL end kext weak_import 5935650 + +@item -mone-byte-bool +@opindex mone-byte-bool +Override the defaults for @samp{bool} so that @samp{sizeof(bool)==1}. +By default @samp{sizeof(bool)} is @samp{4} when compiling for +Darwin/PowerPC and @samp{1} when compiling for Darwin/x86, so this +option has no effect on x86. + +@strong{Warning:} The @option{-mone-byte-bool} switch causes GCC +to generate code that is not binary compatible with code generated +without that switch. Using this switch may require recompiling all +other modules in a program, including system libraries. Use this +switch to conform to a non-default data model. + +@item -mfix-and-continue +@itemx -ffix-and-continue +@itemx -findirect-data +@opindex mfix-and-continue +@opindex ffix-and-continue +@opindex findirect-data +Generate code suitable for fast turn around development. Needed to +enable gdb to dynamically load @code{.o} files into already running +programs. @option{-findirect-data} and @option{-ffix-and-continue} +are provided for backwards compatibility. + +@c APPLE LOCAL KEXT +@item -fapple-kext +@c APPLE LOCAL KEXT indirect-virtual-calls --sts +@itemx -findirect-virtual-calls +@c APPLE LOCAL KEXT terminated-vtables +@itemx -fterminated-vtables +@c APPLE LOCAL KEXT +@opindex fapple-kext +@c APPLE LOCAL KEXT indirect-virtual-calls --sts +@opindex findirect-virtual-calls +@c APPLE LOCAL KEXT terminated-vtables +@opindex fterminated-vtables +@c APPLE LOCAL begin KEXT +Alter vtables, destructors, and other implementation details to more +closely resemble the GCC 2.95 ABI for PowerPC and 32-bit i386. This +is to make kernel extensions loadable by Darwin kernels, and is +required to build any Darwin kernel extension. In addition, virtual +calls are not made directly, instead, code is generated to always go +through the virtual table, as virtual tables can be patched by the +kernel module loader. Vtables are altered by adding a zero word at +the end of every vtable. @option{-findirect-virtual-calls} and +@option{-fterminated-vtables} are accepted for backwards compatibility +but will be removed in the future. Additionally implies +most of @option{-mkernel} except for @option{-msoft-float} and +@option{-mlong-branch} for PowerPC targets. (APPLE ONLY) +@c APPLE LOCAL end KEXT + +@c APPLE LOCAL begin pascal strings +@item -mpascal-strings +Allow Pascal-style string literals to be constructed. This option +implies @option{-Wpointer-sign} so that conversions between +Pascal-style strings and C-style strings are warned about. (APPLE +ONLY) + +@xref{Pascal Strings,,Constructing String Literals with a Pascal-style +Length Byte}, for more information on the syntax and semantics of Pascal +string literals. +@c APPLE LOCAL end pascal strings + +@item -all_load +@opindex all_load +Loads all members of static archive libraries. +See man ld(1) for more information. + +@item -arch_errors_fatal +@opindex arch_errors_fatal +Cause the errors having to do with files that have the wrong architecture +to be fatal. + +@item -bind_at_load +@opindex bind_at_load +Causes the output file to be marked such that the dynamic linker will +bind all undefined references when the file is loaded or launched. + +@item -bundle +@opindex bundle +Produce a Mach-o bundle format file. +See man ld(1) for more information. + +@item -bundle_loader @var{executable} +@opindex bundle_loader +This option specifies the @var{executable} that will be loading the build +output file being linked. See man ld(1) for more information. + +@item -dynamiclib +@opindex dynamiclib +When passed this option, GCC will produce a dynamic library instead of +an executable when linking, using the Darwin @file{libtool} command. + +@item -force_cpusubtype_ALL +@opindex force_cpusubtype_ALL +This causes GCC's output file to have the @var{ALL} subtype, instead of +one controlled by the @option{-mcpu} or @option{-march} option. + +@c APPLE LOCAL begin 7519550 force local +@item -force_load @var{library_name} +@opindex force_load +Loads all members of named static archive library. +See man ld(1) for more information. +@c APPLE LOCAL end 7519550 force local + +@item -allowable_client @var{client_name} +@itemx -client_name +@itemx -compatibility_version +@itemx -current_version +@itemx -dead_strip +@itemx -dependency-file +@itemx -dylib_file +@itemx -dylinker_install_name +@itemx -dynamic +@itemx -exported_symbols_list +@itemx -filelist +@itemx -flat_namespace +@itemx -force_flat_namespace +@itemx -headerpad_max_install_names +@itemx -image_base +@itemx -init +@itemx -install_name +@itemx -keep_private_externs +@itemx -multi_module +@itemx -multiply_defined +@itemx -multiply_defined_unused +@itemx -noall_load +@itemx -no_dead_strip_inits_and_terms +@itemx -nofixprebinding +@itemx -nomultidefs +@itemx -noprebind +@itemx -noseglinkedit +@itemx -pagezero_size +@itemx -prebind +@itemx -prebind_all_twolevel_modules +@itemx -private_bundle +@itemx -read_only_relocs +@itemx -sectalign +@itemx -sectobjectsymbols +@itemx -whyload +@itemx -seg1addr +@itemx -sectcreate +@itemx -sectobjectsymbols +@itemx -sectorder +@itemx -segaddr +@itemx -segs_read_only_addr +@itemx -segs_read_write_addr +@itemx -seg_addr_table +@itemx -seg_addr_table_filename +@itemx -seglinkedit +@itemx -segprot +@itemx -segs_read_only_addr +@itemx -segs_read_write_addr +@itemx -single_module +@itemx -static +@itemx -sub_library +@itemx -sub_umbrella +@itemx -twolevel_namespace +@itemx -umbrella +@itemx -undefined +@itemx -unexported_symbols_list +@itemx -weak_reference_mismatches +@itemx -whatsloaded + +@opindex allowable_client +@opindex client_name +@opindex compatibility_version +@opindex current_version +@opindex dead_strip +@opindex dependency-file +@opindex dylib_file +@opindex dylinker_install_name +@opindex dynamic +@opindex exported_symbols_list +@opindex filelist +@opindex flat_namespace +@opindex force_flat_namespace +@opindex headerpad_max_install_names +@opindex image_base +@opindex init +@opindex install_name +@opindex keep_private_externs +@opindex multi_module +@opindex multiply_defined +@opindex multiply_defined_unused +@opindex noall_load +@opindex no_dead_strip_inits_and_terms +@opindex nofixprebinding +@opindex nomultidefs +@opindex noprebind +@opindex noseglinkedit +@opindex pagezero_size +@opindex prebind +@opindex prebind_all_twolevel_modules +@opindex private_bundle +@opindex read_only_relocs +@opindex sectalign +@opindex sectobjectsymbols +@opindex whyload +@opindex seg1addr +@opindex sectcreate +@opindex sectobjectsymbols +@opindex sectorder +@opindex segaddr +@opindex segs_read_only_addr +@opindex segs_read_write_addr +@opindex seg_addr_table +@opindex seg_addr_table_filename +@opindex seglinkedit +@opindex segprot +@opindex segs_read_only_addr +@opindex segs_read_write_addr +@opindex single_module +@opindex static +@opindex sub_library +@opindex sub_umbrella +@opindex twolevel_namespace +@opindex umbrella +@opindex undefined +@opindex unexported_symbols_list +@opindex weak_reference_mismatches +@opindex whatsloaded + +These options are passed to the Darwin linker. The Darwin linker man page +describes them in detail. +@end table + +@c APPLE LOCAL prune man page +@ignore +@node DEC Alpha Options +@subsection DEC Alpha Options + +These @samp{-m} options are defined for the DEC Alpha implementations: + +@table @gcctabopt +@item -mno-soft-float +@itemx -msoft-float +@opindex mno-soft-float +@opindex msoft-float +Use (do not use) the hardware floating-point instructions for +floating-point operations. When @option{-msoft-float} is specified, +functions in @file{libgcc.a} will be used to perform floating-point +operations. Unless they are replaced by routines that emulate the +floating-point operations, or compiled in such a way as to call such +emulations routines, these routines will issue floating-point +operations. If you are compiling for an Alpha without floating-point +operations, you must ensure that the library is built so as not to call +them. + +Note that Alpha implementations without floating-point operations are +required to have floating-point registers. + +@item -mfp-reg +@itemx -mno-fp-regs +@opindex mfp-reg +@opindex mno-fp-regs +Generate code that uses (does not use) the floating-point register set. +@option{-mno-fp-regs} implies @option{-msoft-float}. If the floating-point +register set is not used, floating point operands are passed in integer +registers as if they were integers and floating-point results are passed +in @code{$0} instead of @code{$f0}. This is a non-standard calling sequence, +so any function with a floating-point argument or return value called by code +compiled with @option{-mno-fp-regs} must also be compiled with that +option. + +A typical use of this option is building a kernel that does not use, +and hence need not save and restore, any floating-point registers. + +@item -mieee +@opindex mieee +The Alpha architecture implements floating-point hardware optimized for +maximum performance. It is mostly compliant with the IEEE floating +point standard. However, for full compliance, software assistance is +required. This option generates code fully IEEE compliant code +@emph{except} that the @var{inexact-flag} is not maintained (see below). +If this option is turned on, the preprocessor macro @code{_IEEE_FP} is +defined during compilation. The resulting code is less efficient but is +able to correctly support denormalized numbers and exceptional IEEE +values such as not-a-number and plus/minus infinity. Other Alpha +compilers call this option @option{-ieee_with_no_inexact}. + +@item -mieee-with-inexact +@opindex mieee-with-inexact +This is like @option{-mieee} except the generated code also maintains +the IEEE @var{inexact-flag}. Turning on this option causes the +generated code to implement fully-compliant IEEE math. In addition to +@code{_IEEE_FP}, @code{_IEEE_FP_EXACT} is defined as a preprocessor +macro. On some Alpha implementations the resulting code may execute +significantly slower than the code generated by default. Since there is +very little code that depends on the @var{inexact-flag}, you should +normally not specify this option. Other Alpha compilers call this +option @option{-ieee_with_inexact}. + +@item -mfp-trap-mode=@var{trap-mode} +@opindex mfp-trap-mode +This option controls what floating-point related traps are enabled. +Other Alpha compilers call this option @option{-fptm @var{trap-mode}}. +The trap mode can be set to one of four values: + +@table @samp +@item n +This is the default (normal) setting. The only traps that are enabled +are the ones that cannot be disabled in software (e.g., division by zero +trap). + +@item u +In addition to the traps enabled by @samp{n}, underflow traps are enabled +as well. + +@item su +Like @samp{u}, but the instructions are marked to be safe for software +completion (see Alpha architecture manual for details). + +@item sui +Like @samp{su}, but inexact traps are enabled as well. +@end table + +@item -mfp-rounding-mode=@var{rounding-mode} +@opindex mfp-rounding-mode +Selects the IEEE rounding mode. Other Alpha compilers call this option +@option{-fprm @var{rounding-mode}}. The @var{rounding-mode} can be one +of: + +@table @samp +@item n +Normal IEEE rounding mode. Floating point numbers are rounded towards +the nearest machine number or towards the even machine number in case +of a tie. + +@item m +Round towards minus infinity. + +@item c +Chopped rounding mode. Floating point numbers are rounded towards zero. + +@item d +Dynamic rounding mode. A field in the floating point control register +(@var{fpcr}, see Alpha architecture reference manual) controls the +rounding mode in effect. The C library initializes this register for +rounding towards plus infinity. Thus, unless your program modifies the +@var{fpcr}, @samp{d} corresponds to round towards plus infinity. +@end table + +@item -mtrap-precision=@var{trap-precision} +@opindex mtrap-precision +In the Alpha architecture, floating point traps are imprecise. This +means without software assistance it is impossible to recover from a +floating trap and program execution normally needs to be terminated. +GCC can generate code that can assist operating system trap handlers +in determining the exact location that caused a floating point trap. +Depending on the requirements of an application, different levels of +precisions can be selected: + +@table @samp +@item p +Program precision. This option is the default and means a trap handler +can only identify which program caused a floating point exception. + +@item f +Function precision. The trap handler can determine the function that +caused a floating point exception. + +@item i +Instruction precision. The trap handler can determine the exact +instruction that caused a floating point exception. +@end table + +Other Alpha compilers provide the equivalent options called +@option{-scope_safe} and @option{-resumption_safe}. + +@item -mieee-conformant +@opindex mieee-conformant +This option marks the generated code as IEEE conformant. You must not +use this option unless you also specify @option{-mtrap-precision=i} and either +@option{-mfp-trap-mode=su} or @option{-mfp-trap-mode=sui}. Its only effect +is to emit the line @samp{.eflag 48} in the function prologue of the +generated assembly file. Under DEC Unix, this has the effect that +IEEE-conformant math library routines will be linked in. + +@item -mbuild-constants +@opindex mbuild-constants +Normally GCC examines a 32- or 64-bit integer constant to +see if it can construct it from smaller constants in two or three +instructions. If it cannot, it will output the constant as a literal and +generate code to load it from the data segment at runtime. + +Use this option to require GCC to construct @emph{all} integer constants +using code, even if it takes more instructions (the maximum is six). + +You would typically use this option to build a shared library dynamic +loader. Itself a shared library, it must relocate itself in memory +before it can find the variables and constants in its own data segment. + +@item -malpha-as +@itemx -mgas +@opindex malpha-as +@opindex mgas +Select whether to generate code to be assembled by the vendor-supplied +assembler (@option{-malpha-as}) or by the GNU assembler @option{-mgas}. + +@item -mbwx +@itemx -mno-bwx +@itemx -mcix +@itemx -mno-cix +@itemx -mfix +@itemx -mno-fix +@itemx -mmax +@itemx -mno-max +@opindex mbwx +@opindex mno-bwx +@opindex mcix +@opindex mno-cix +@opindex mfix +@opindex mno-fix +@opindex mmax +@opindex mno-max +Indicate whether GCC should generate code to use the optional BWX, +CIX, FIX and MAX instruction sets. The default is to use the instruction +sets supported by the CPU type specified via @option{-mcpu=} option or that +of the CPU on which GCC was built if none was specified. + +@item -mfloat-vax +@itemx -mfloat-ieee +@opindex mfloat-vax +@opindex mfloat-ieee +Generate code that uses (does not use) VAX F and G floating point +arithmetic instead of IEEE single and double precision. + +@item -mexplicit-relocs +@itemx -mno-explicit-relocs +@opindex mexplicit-relocs +@opindex mno-explicit-relocs +Older Alpha assemblers provided no way to generate symbol relocations +except via assembler macros. Use of these macros does not allow +optimal instruction scheduling. GNU binutils as of version 2.12 +supports a new syntax that allows the compiler to explicitly mark +which relocations should apply to which instructions. This option +is mostly useful for debugging, as GCC detects the capabilities of +the assembler when it is built and sets the default accordingly. + +@item -msmall-data +@itemx -mlarge-data +@opindex msmall-data +@opindex mlarge-data +When @option{-mexplicit-relocs} is in effect, static data is +accessed via @dfn{gp-relative} relocations. When @option{-msmall-data} +is used, objects 8 bytes long or smaller are placed in a @dfn{small data area} +(the @code{.sdata} and @code{.sbss} sections) and are accessed via +16-bit relocations off of the @code{$gp} register. This limits the +size of the small data area to 64KB, but allows the variables to be +directly accessed via a single instruction. + +The default is @option{-mlarge-data}. With this option the data area +is limited to just below 2GB@. Programs that require more than 2GB of +data must use @code{malloc} or @code{mmap} to allocate the data in the +heap instead of in the program's data segment. + +When generating code for shared libraries, @option{-fpic} implies +@option{-msmall-data} and @option{-fPIC} implies @option{-mlarge-data}. + +@item -msmall-text +@itemx -mlarge-text +@opindex msmall-text +@opindex mlarge-text +When @option{-msmall-text} is used, the compiler assumes that the +code of the entire program (or shared library) fits in 4MB, and is +thus reachable with a branch instruction. When @option{-msmall-data} +is used, the compiler can assume that all local symbols share the +same @code{$gp} value, and thus reduce the number of instructions +required for a function call from 4 to 1. + +The default is @option{-mlarge-text}. + +@item -mcpu=@var{cpu_type} +@opindex mcpu +Set the instruction set and instruction scheduling parameters for +machine type @var{cpu_type}. You can specify either the @samp{EV} +style name or the corresponding chip number. GCC supports scheduling +parameters for the EV4, EV5 and EV6 family of processors and will +choose the default values for the instruction set from the processor +you specify. If you do not specify a processor type, GCC will default +to the processor on which the compiler was built. + +Supported values for @var{cpu_type} are + +@table @samp +@item ev4 +@itemx ev45 +@itemx 21064 +Schedules as an EV4 and has no instruction set extensions. + +@item ev5 +@itemx 21164 +Schedules as an EV5 and has no instruction set extensions. + +@item ev56 +@itemx 21164a +Schedules as an EV5 and supports the BWX extension. + +@item pca56 +@itemx 21164pc +@itemx 21164PC +Schedules as an EV5 and supports the BWX and MAX extensions. + +@item ev6 +@itemx 21264 +Schedules as an EV6 and supports the BWX, FIX, and MAX extensions. + +@item ev67 +@itemx 21264a +Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions. +@end table + +@item -mtune=@var{cpu_type} +@opindex mtune +Set only the instruction scheduling parameters for machine type +@var{cpu_type}. The instruction set is not changed. + +@item -mmemory-latency=@var{time} +@opindex mmemory-latency +Sets the latency the scheduler should assume for typical memory +references as seen by the application. This number is highly +dependent on the memory access patterns used by the application +and the size of the external cache on the machine. + +Valid options for @var{time} are + +@table @samp +@item @var{number} +A decimal number representing clock cycles. + +@item L1 +@itemx L2 +@itemx L3 +@itemx main +The compiler contains estimates of the number of clock cycles for +``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3 caches +(also called Dcache, Scache, and Bcache), as well as to main memory. +Note that L3 is only valid for EV5. + +@end table +@end table + +@node DEC Alpha/VMS Options +@subsection DEC Alpha/VMS Options + +These @samp{-m} options are defined for the DEC Alpha/VMS implementations: + +@table @gcctabopt +@item -mvms-return-codes +@opindex mvms-return-codes +Return VMS condition codes from main. The default is to return POSIX +style condition (e.g.@ error) codes. +@end table + +@node FRV Options +@subsection FRV Options +@cindex FRV Options + +@table @gcctabopt +@item -mgpr-32 +@opindex mgpr-32 + +Only use the first 32 general purpose registers. + +@item -mgpr-64 +@opindex mgpr-64 + +Use all 64 general purpose registers. + +@item -mfpr-32 +@opindex mfpr-32 + +Use only the first 32 floating point registers. + +@item -mfpr-64 +@opindex mfpr-64 + +Use all 64 floating point registers + +@item -mhard-float +@opindex mhard-float + +Use hardware instructions for floating point operations. + +@item -msoft-float +@opindex msoft-float + +Use library routines for floating point operations. + +@item -malloc-cc +@opindex malloc-cc + +Dynamically allocate condition code registers. + +@item -mfixed-cc +@opindex mfixed-cc + +Do not try to dynamically allocate condition code registers, only +use @code{icc0} and @code{fcc0}. + +@item -mdword +@opindex mdword + +Change ABI to use double word insns. + +@item -mno-dword +@opindex mno-dword + +Do not use double word instructions. + +@item -mdouble +@opindex mdouble + +Use floating point double instructions. + +@item -mno-double +@opindex mno-double + +Do not use floating point double instructions. + +@item -mmedia +@opindex mmedia + +Use media instructions. + +@item -mno-media +@opindex mno-media + +Do not use media instructions. + +@item -mmuladd +@opindex mmuladd + +Use multiply and add/subtract instructions. + +@item -mno-muladd +@opindex mno-muladd + +Do not use multiply and add/subtract instructions. + +@item -mfdpic +@opindex mfdpic + +Select the FDPIC ABI, that uses function descriptors to represent +pointers to functions. Without any PIC/PIE-related options, it +implies @option{-fPIE}. With @option{-fpic} or @option{-fpie}, it +assumes GOT entries and small data are within a 12-bit range from the +GOT base address; with @option{-fPIC} or @option{-fPIE}, GOT offsets +are computed with 32 bits. + +@item -minline-plt +@opindex minline-plt + +Enable inlining of PLT entries in function calls to functions that are +not known to bind locally. It has no effect without @option{-mfdpic}. +It's enabled by default if optimizing for speed and compiling for +shared libraries (i.e., @option{-fPIC} or @option{-fpic}), or when an +optimization option such as @option{-O3} or above is present in the +command line. + +@item -mTLS +@opindex TLS + +Assume a large TLS segment when generating thread-local code. + +@item -mtls +@opindex tls + +Do not assume a large TLS segment when generating thread-local code. + +@item -mgprel-ro +@opindex mgprel-ro + +Enable the use of @code{GPREL} relocations in the FDPIC ABI for data +that is known to be in read-only sections. It's enabled by default, +except for @option{-fpic} or @option{-fpie}: even though it may help +make the global offset table smaller, it trades 1 instruction for 4. +With @option{-fPIC} or @option{-fPIE}, it trades 3 instructions for 4, +one of which may be shared by multiple symbols, and it avoids the need +for a GOT entry for the referenced symbol, so it's more likely to be a +win. If it is not, @option{-mno-gprel-ro} can be used to disable it. + +@item -multilib-library-pic +@opindex multilib-library-pic + +Link with the (library, not FD) pic libraries. It's implied by +@option{-mlibrary-pic}, as well as by @option{-fPIC} and +@option{-fpic} without @option{-mfdpic}. You should never have to use +it explicitly. + +@item -mlinked-fp +@opindex mlinked-fp + +Follow the EABI requirement of always creating a frame pointer whenever +a stack frame is allocated. This option is enabled by default and can +be disabled with @option{-mno-linked-fp}. + +@item -mlong-calls +@opindex mlong-calls + +Use indirect addressing to call functions outside the current +compilation unit. This allows the functions to be placed anywhere +within the 32-bit address space. + +@item -malign-labels +@opindex malign-labels + +Try to align labels to an 8-byte boundary by inserting nops into the +previous packet. This option only has an effect when VLIW packing +is enabled. It doesn't create new packets; it merely adds nops to +existing ones. + +@item -mlibrary-pic +@opindex mlibrary-pic + +Generate position-independent EABI code. + +@item -macc-4 +@opindex macc-4 + +Use only the first four media accumulator registers. + +@item -macc-8 +@opindex macc-8 + +Use all eight media accumulator registers. + +@item -mpack +@opindex mpack + +Pack VLIW instructions. + +@item -mno-pack +@opindex mno-pack + +Do not pack VLIW instructions. + +@item -mno-eflags +@opindex mno-eflags + +Do not mark ABI switches in e_flags. + +@item -mcond-move +@opindex mcond-move + +Enable the use of conditional-move instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-cond-move +@opindex mno-cond-move + +Disable the use of conditional-move instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mscc +@opindex mscc + +Enable the use of conditional set instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-scc +@opindex mno-scc + +Disable the use of conditional set instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mcond-exec +@opindex mcond-exec + +Enable the use of conditional execution (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-cond-exec +@opindex mno-cond-exec + +Disable the use of conditional execution. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mvliw-branch +@opindex mvliw-branch + +Run a pass to pack branches into VLIW instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-vliw-branch +@opindex mno-vliw-branch + +Do not run a pass to pack branches into VLIW instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mmulti-cond-exec +@opindex mmulti-cond-exec + +Enable optimization of @code{&&} and @code{||} in conditional execution +(default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-multi-cond-exec +@opindex mno-multi-cond-exec + +Disable optimization of @code{&&} and @code{||} in conditional execution. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mnested-cond-exec +@opindex mnested-cond-exec + +Enable nested conditional execution optimizations (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-nested-cond-exec +@opindex mno-nested-cond-exec + +Disable nested conditional execution optimizations. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -moptimize-membar +@opindex moptimize-membar + +This switch removes redundant @code{membar} instructions from the +compiler generated code. It is enabled by default. + +@item -mno-optimize-membar +@opindex mno-optimize-membar + +This switch disables the automatic removal of redundant @code{membar} +instructions from the generated code. + +@item -mtomcat-stats +@opindex mtomcat-stats + +Cause gas to print out tomcat statistics. + +@item -mcpu=@var{cpu} +@opindex mcpu + +Select the processor type for which to generate code. Possible values are +@samp{frv}, @samp{fr550}, @samp{tomcat}, @samp{fr500}, @samp{fr450}, +@samp{fr405}, @samp{fr400}, @samp{fr300} and @samp{simple}. + +@end table + +@node GNU/Linux Options +@subsection GNU/Linux Options + +These @samp{-m} options are defined for GNU/Linux targets: + +@table @gcctabopt +@item -mglibc +@opindex mglibc +Use the GNU C library instead of uClibc. This is the default except +on @samp{*-*-linux-*uclibc*} targets. + +@item -muclibc +@opindex muclibc +Use uClibc instead of the GNU C library. This is the default on +@samp{*-*-linux-*uclibc*} targets. +@end table + +@node H8/300 Options +@subsection H8/300 Options + +These @samp{-m} options are defined for the H8/300 implementations: + +@table @gcctabopt +@item -mrelax +@opindex mrelax +Shorten some address references at link time, when possible; uses the +linker option @option{-relax}. @xref{H8/300,, @code{ld} and the H8/300, +ld, Using ld}, for a fuller description. + +@item -mh +@opindex mh +Generate code for the H8/300H@. + +@item -ms +@opindex ms +Generate code for the H8S@. + +@item -mn +@opindex mn +Generate code for the H8S and H8/300H in the normal mode. This switch +must be used either with @option{-mh} or @option{-ms}. + +@item -ms2600 +@opindex ms2600 +Generate code for the H8S/2600. This switch must be used with @option{-ms}. + +@item -mint32 +@opindex mint32 +Make @code{int} data 32 bits by default. + +@item -malign-300 +@opindex malign-300 +On the H8/300H and H8S, use the same alignment rules as for the H8/300. +The default for the H8/300H and H8S is to align longs and floats on 4 +byte boundaries. +@option{-malign-300} causes them to be aligned on 2 byte boundaries. +This option has no effect on the H8/300. +@end table + +@node HPPA Options +@subsection HPPA Options +@cindex HPPA Options + +These @samp{-m} options are defined for the HPPA family of computers: + +@table @gcctabopt +@item -march=@var{architecture-type} +@opindex march +Generate code for the specified architecture. The choices for +@var{architecture-type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA +1.1, and @samp{2.0} for PA 2.0 processors. Refer to +@file{/usr/lib/sched.models} on an HP-UX system to determine the proper +architecture option for your machine. Code compiled for lower numbered +architectures will run on higher numbered architectures, but not the +other way around. + +@item -mpa-risc-1-0 +@itemx -mpa-risc-1-1 +@itemx -mpa-risc-2-0 +@opindex mpa-risc-1-0 +@opindex mpa-risc-1-1 +@opindex mpa-risc-2-0 +Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively. + +@item -mbig-switch +@opindex mbig-switch +Generate code suitable for big switch tables. Use this option only if +the assembler/linker complain about out of range branches within a switch +table. + +@item -mjump-in-delay +@opindex mjump-in-delay +Fill delay slots of function calls with unconditional jump instructions +by modifying the return pointer for the function call to be the target +of the conditional jump. + +@item -mdisable-fpregs +@opindex mdisable-fpregs +Prevent floating point registers from being used in any manner. This is +necessary for compiling kernels which perform lazy context switching of +floating point registers. If you use this option and attempt to perform +floating point operations, the compiler will abort. + +@item -mdisable-indexing +@opindex mdisable-indexing +Prevent the compiler from using indexing address modes. This avoids some +rather obscure problems when compiling MIG generated code under MACH@. + +@item -mno-space-regs +@opindex mno-space-regs +Generate code that assumes the target has no space registers. This allows +GCC to generate faster indirect calls and use unscaled index address modes. + +Such code is suitable for level 0 PA systems and kernels. + +@item -mfast-indirect-calls +@opindex mfast-indirect-calls +Generate code that assumes calls never cross space boundaries. This +allows GCC to emit code which performs faster indirect calls. + +This option will not work in the presence of shared libraries or nested +functions. + +@item -mfixed-range=@var{register-range} +@opindex mfixed-range +Generate code treating the given register range as fixed registers. +A fixed register is one that the register allocator can not use. This is +useful when compiling kernel code. A register range is specified as +two registers separated by a dash. Multiple register ranges can be +specified separated by a comma. + +@item -mlong-load-store +@opindex mlong-load-store +Generate 3-instruction load and store sequences as sometimes required by +the HP-UX 10 linker. This is equivalent to the @samp{+k} option to +the HP compilers. + +@item -mportable-runtime +@opindex mportable-runtime +Use the portable calling conventions proposed by HP for ELF systems. + +@item -mgas +@opindex mgas +Enable the use of assembler directives only GAS understands. + +@item -mschedule=@var{cpu-type} +@opindex mschedule +Schedule code according to the constraints for the machine type +@var{cpu-type}. The choices for @var{cpu-type} are @samp{700} +@samp{7100}, @samp{7100LC}, @samp{7200}, @samp{7300} and @samp{8000}. Refer +to @file{/usr/lib/sched.models} on an HP-UX system to determine the +proper scheduling option for your machine. The default scheduling is +@samp{8000}. + +@item -mlinker-opt +@opindex mlinker-opt +Enable the optimization pass in the HP-UX linker. Note this makes symbolic +debugging impossible. It also triggers a bug in the HP-UX 8 and HP-UX 9 +linkers in which they give bogus error messages when linking some programs. + +@item -msoft-float +@opindex msoft-float +Generate output containing library calls for floating point. +@strong{Warning:} the requisite libraries are not available for all HPPA +targets. Normally the facilities of the machine's usual C compiler are +used, but this cannot be done directly in cross-compilation. You must make +your own arrangements to provide suitable library functions for +cross-compilation. The embedded target @samp{hppa1.1-*-pro} +does provide software floating point support. + +@option{-msoft-float} changes the calling convention in the output file; +therefore, it is only useful if you compile @emph{all} of a program with +this option. In particular, you need to compile @file{libgcc.a}, the +library that comes with GCC, with @option{-msoft-float} in order for +this to work. + +@item -msio +@opindex msio +Generate the predefine, @code{_SIO}, for server IO@. The default is +@option{-mwsio}. This generates the predefines, @code{__hp9000s700}, +@code{__hp9000s700__} and @code{_WSIO}, for workstation IO@. These +options are available under HP-UX and HI-UX@. + +@item -mgnu-ld +@opindex gnu-ld +Use GNU ld specific options. This passes @option{-shared} to ld when +building a shared library. It is the default when GCC is configured, +explicitly or implicitly, with the GNU linker. This option does not +have any affect on which ld is called, it only changes what parameters +are passed to that ld. The ld that is called is determined by the +@option{--with-ld} configure option, GCC's program search path, and +finally by the user's @env{PATH}. The linker used by GCC can be printed +using @samp{which `gcc -print-prog-name=ld`}. This option is only available +on the 64 bit HP-UX GCC, i.e. configured with @samp{hppa*64*-*-hpux*}. + +@item -mhp-ld +@opindex hp-ld +Use HP ld specific options. This passes @option{-b} to ld when building +a shared library and passes @option{+Accept TypeMismatch} to ld on all +links. It is the default when GCC is configured, explicitly or +implicitly, with the HP linker. This option does not have any affect on +which ld is called, it only changes what parameters are passed to that +ld. The ld that is called is determined by the @option{--with-ld} +configure option, GCC's program search path, and finally by the user's +@env{PATH}. The linker used by GCC can be printed using @samp{which +`gcc -print-prog-name=ld`}. This option is only available on the 64 bit +HP-UX GCC, i.e. configured with @samp{hppa*64*-*-hpux*}. + +@item -mlong-calls +@opindex mno-long-calls +Generate code that uses long call sequences. This ensures that a call +is always able to reach linker generated stubs. The default is to generate +long calls only when the distance from the call site to the beginning +of the function or translation unit, as the case may be, exceeds a +predefined limit set by the branch type being used. The limits for +normal calls are 7,600,000 and 240,000 bytes, respectively for the +PA 2.0 and PA 1.X architectures. Sibcalls are always limited at +240,000 bytes. + +Distances are measured from the beginning of functions when using the +@option{-ffunction-sections} option, or when using the @option{-mgas} +and @option{-mno-portable-runtime} options together under HP-UX with +the SOM linker. + +It is normally not desirable to use this option as it will degrade +performance. However, it may be useful in large applications, +particularly when partial linking is used to build the application. + +The types of long calls used depends on the capabilities of the +assembler and linker, and the type of code being generated. The +impact on systems that support long absolute calls, and long pic +symbol-difference or pc-relative calls should be relatively small. +However, an indirect call is used on 32-bit ELF systems in pic code +and it is quite long. + +@item -munix=@var{unix-std} +@opindex march +Generate compiler predefines and select a startfile for the specified +UNIX standard. The choices for @var{unix-std} are @samp{93}, @samp{95} +and @samp{98}. @samp{93} is supported on all HP-UX versions. @samp{95} +is available on HP-UX 10.10 and later. @samp{98} is available on HP-UX +11.11 and later. The default values are @samp{93} for HP-UX 10.00, +@samp{95} for HP-UX 10.10 though to 11.00, and @samp{98} for HP-UX 11.11 +and later. + +@option{-munix=93} provides the same predefines as GCC 3.3 and 3.4. +@option{-munix=95} provides additional predefines for @code{XOPEN_UNIX} +and @code{_XOPEN_SOURCE_EXTENDED}, and the startfile @file{unix95.o}. +@option{-munix=98} provides additional predefines for @code{_XOPEN_UNIX}, +@code{_XOPEN_SOURCE_EXTENDED}, @code{_INCLUDE__STDC_A1_SOURCE} and +@code{_INCLUDE_XOPEN_SOURCE_500}, and the startfile @file{unix98.o}. + +It is @emph{important} to note that this option changes the interfaces +for various library routines. It also affects the operational behavior +of the C library. Thus, @emph{extreme} care is needed in using this +option. + +Library code that is intended to operate with more than one UNIX +standard must test, set and restore the variable @var{__xpg4_extended_mask} +as appropriate. Most GNU software doesn't provide this capability. + +@item -nolibdld +@opindex nolibdld +Suppress the generation of link options to search libdld.sl when the +@option{-static} option is specified on HP-UX 10 and later. + +@item -static +@opindex static +The HP-UX implementation of setlocale in libc has a dependency on +libdld.sl. There isn't an archive version of libdld.sl. Thus, +when the @option{-static} option is specified, special link options +are needed to resolve this dependency. + +On HP-UX 10 and later, the GCC driver adds the necessary options to +link with libdld.sl when the @option{-static} option is specified. +This causes the resulting binary to be dynamic. On the 64-bit port, +the linkers generate dynamic binaries by default in any case. The +@option{-nolibdld} option can be used to prevent the GCC driver from +adding these link options. + +@item -threads +@opindex threads +Add support for multithreading with the @dfn{dce thread} library +under HP-UX@. This option sets flags for both the preprocessor and +linker. +@end table +@c APPLE LOCAL prune man page +@end ignore + +@node i386 and x86-64 Options +@subsection Intel 386 and AMD x86-64 Options +@cindex i386 Options +@cindex x86-64 Options +@cindex Intel 386 Options +@cindex AMD x86-64 Options + +These @samp{-m} options are defined for the i386 and x86-64 family of +computers: + +@table @gcctabopt +@item -mtune=@var{cpu-type} +@opindex mtune +Tune to @var{cpu-type} everything applicable about the generated code, except +for the ABI and the set of available instructions. The choices for +@var{cpu-type} are: +@table @emph +@item generic +Produce code optimized for the most common IA32/AMD64/EM64T processors. +If you know the CPU on which your code will run, then you should use +the corresponding @option{-mtune} option instead of +@option{-mtune=generic}. But, if you do not know exactly what CPU users +of your application will have, then you should use this option. + +As new processors are deployed in the marketplace, the behavior of this +option will change. Therefore, if you upgrade to a newer version of +GCC, the code generated option will change to reflect the processors +that were most common when that version of GCC was released. + +There is no @option{-march=generic} option because @option{-march} +indicates the instruction set the compiler can use, and there is no +generic instruction set applicable to all processors. In contrast, +@option{-mtune} indicates the processor (or, in this case, collection of +processors) for which the code is optimized. +@item native +This selects the CPU to tune for at compilation time by determining +the processor type of the compiling machine. Using @option{-mtune=native} +will produce code optimized for the local machine under the constraints +of the selected instruction set. Using @option{-march=native} will +enable all instruction subsets supported by the local machine (hence +the result might not run on different machines). +@item i386 +Original Intel's i386 CPU@. +@item i486 +Intel's i486 CPU@. (No scheduling is implemented for this chip.) +@item i586, pentium +Intel Pentium CPU with no MMX support. +@item pentium-mmx +Intel PentiumMMX CPU based on Pentium core with MMX instruction set support. +@item pentiumpro +Intel PentiumPro CPU@. +@item i686 +Same as @code{generic}, but when used as @code{march} option, PentiumPro +instruction set will be used, so the code will run on all i686 family chips. +@item pentium2 +Intel Pentium2 CPU based on PentiumPro core with MMX instruction set support. +@item pentium3, pentium3m +Intel Pentium3 CPU based on PentiumPro core with MMX and SSE instruction set +support. +@item pentium-m +Low power version of Intel Pentium3 CPU with MMX, SSE and SSE2 instruction set +support. Used by Centrino notebooks. +@item pentium4, pentium4m +Intel Pentium4 CPU with MMX, SSE and SSE2 instruction set support. +@item prescott +Improved version of Intel Pentium4 CPU with MMX, SSE, SSE2 and SSE3 instruction +set support. +@item nocona +Improved version of Intel Pentium4 CPU with 64-bit extensions, MMX, SSE, +SSE2 and SSE3 instruction set support. +@c APPLE LOCAL begin mainline +@item core2 +Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 +instruction set support. +@c APPLE LOCAL end mainline +@item k6 +AMD K6 CPU with MMX instruction set support. +@item k6-2, k6-3 +Improved versions of AMD K6 CPU with MMX and 3dNOW! instruction set support. +@item athlon, athlon-tbird +AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW! and SSE prefetch instructions +support. +@item athlon-4, athlon-xp, athlon-mp +Improved AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW! and full SSE +instruction set support. +@item k8, opteron, athlon64, athlon-fx +AMD K8 core based CPUs with x86-64 instruction set support. (This supersets +MMX, SSE, SSE2, 3dNOW!, enhanced 3dNOW! and 64-bit instruction set extensions.) +@item winchip-c6 +IDT Winchip C6 CPU, dealt in same way as i486 with additional MMX instruction +set support. +@item winchip2 +IDT Winchip2 CPU, dealt in same way as i486 with additional MMX and 3dNOW! +instruction set support. +@item c3 +Via C3 CPU with MMX and 3dNOW! instruction set support. (No scheduling is +implemented for this chip.) +@item c3-2 +Via C3-2 CPU with MMX and SSE instruction set support. (No scheduling is +implemented for this chip.) +@end table + +While picking a specific @var{cpu-type} will schedule things appropriately +for that particular chip, the compiler will not generate any code that +does not run on the i386 without the @option{-march=@var{cpu-type}} option +being used. + +@item -march=@var{cpu-type} +@opindex march +Generate instructions for the machine type @var{cpu-type}. The choices +for @var{cpu-type} are the same as for @option{-mtune}. Moreover, +specifying @option{-march=@var{cpu-type}} implies @option{-mtune=@var{cpu-type}}. + +@item -mcpu=@var{cpu-type} +@opindex mcpu +A deprecated synonym for @option{-mtune}. + +@item -m386 +@itemx -m486 +@itemx -mpentium +@itemx -mpentiumpro +@opindex m386 +@opindex m486 +@opindex mpentium +@opindex mpentiumpro +These options are synonyms for @option{-mtune=i386}, @option{-mtune=i486}, +@option{-mtune=pentium}, and @option{-mtune=pentiumpro} respectively. +These synonyms are deprecated. + +@item -mfpmath=@var{unit} +@opindex march +Generate floating point arithmetics for selected unit @var{unit}. The choices +for @var{unit} are: + +@table @samp +@item 387 +Use the standard 387 floating point coprocessor present majority of chips and +emulated otherwise. Code compiled with this option will run almost everywhere. +The temporary results are computed in 80bit precision instead of precision +specified by the type resulting in slightly different results compared to most +of other chips. See @option{-ffloat-store} for more detailed description. + +This is the default choice for i386 compiler. + +@item sse +Use scalar floating point instructions present in the SSE instruction set. +This instruction set is supported by Pentium3 and newer chips, in the AMD line +by Athlon-4, Athlon-xp and Athlon-mp chips. The earlier version of SSE +instruction set supports only single precision arithmetics, thus the double and +extended precision arithmetics is still done using 387. Later version, present +only in Pentium4 and the future AMD x86-64 chips supports double precision +arithmetics too. + +For the i386 compiler, you need to use @option{-march=@var{cpu-type}}, @option{-msse} +or @option{-msse2} switches to enable SSE extensions and make this option +effective. For the x86-64 compiler, these extensions are enabled by default. + +The resulting code should be considerably faster in the majority of cases and avoid +the numerical instability problems of 387 code, but may break some existing +code that expects temporaries to be 80bit. + +This is the default choice for the x86-64 compiler. + +@item sse,387 +Attempt to utilize both instruction sets at once. This effectively double the +amount of available registers and on chips with separate execution units for +387 and SSE the execution resources too. Use this option with care, as it is +still experimental, because the GCC register allocator does not model separate +functional units well resulting in instable performance. +@end table + +@item -masm=@var{dialect} +@opindex masm=@var{dialect} +Output asm instructions using selected @var{dialect}. Supported +choices are @samp{intel} or @samp{att} (the default one). Darwin does +not support @samp{intel}. + +@item -mieee-fp +@itemx -mno-ieee-fp +@opindex mieee-fp +@opindex mno-ieee-fp +Control whether or not the compiler uses IEEE floating point +comparisons. These handle correctly the case where the result of a +comparison is unordered. + +@item -msoft-float +@opindex msoft-float +Generate output containing library calls for floating point. +@strong{Warning:} the requisite libraries are not part of GCC@. +Normally the facilities of the machine's usual C compiler are used, but +this can't be done directly in cross-compilation. You must make your +own arrangements to provide suitable library functions for +cross-compilation. + +On machines where a function returns floating point results in the 80387 +register stack, some floating point opcodes may be emitted even if +@option{-msoft-float} is used. + +@item -mno-fp-ret-in-387 +@opindex mno-fp-ret-in-387 +Do not use the FPU registers for return values of functions. + +The usual calling convention has functions return values of types +@code{float} and @code{double} in an FPU register, even if there +is no FPU@. The idea is that the operating system should emulate +an FPU@. + +The option @option{-mno-fp-ret-in-387} causes such values to be returned +in ordinary CPU registers instead. + +@item -mno-fancy-math-387 +@opindex mno-fancy-math-387 +Some 387 emulators do not support the @code{sin}, @code{cos} and +@code{sqrt} instructions for the 387. Specify this option to avoid +generating those instructions. This option is the default on FreeBSD, +OpenBSD and NetBSD@. This option is overridden when @option{-march} +indicates that the target cpu will always have an FPU and so the +instruction will not need emulation. As of revision 2.6.1, these +instructions are not generated unless you also use the +@option{-funsafe-math-optimizations} switch. + +@item -malign-double +@itemx -mno-align-double +@opindex malign-double +@opindex mno-align-double +Control whether GCC aligns @code{double}, @code{long double}, and +@code{long long} variables on a two word boundary or a one word +boundary. Aligning @code{double} variables on a two word boundary will +produce code that runs somewhat faster on a @samp{Pentium} at the +expense of more memory. + +On x86-64, @option{-malign-double} is enabled by default. + +@strong{Warning:} if you use the @option{-malign-double} switch, +structures containing the above types will be aligned differently than +the published application binary interface specifications for the 386 +and will not be binary compatible with structures in code compiled +without that switch. + +@item -m96bit-long-double +@itemx -m128bit-long-double +@opindex m96bit-long-double +@opindex m128bit-long-double +These switches control the size of @code{long double} type. The i386 +application binary interface specifies the size to be 96 bits, +so @option{-m96bit-long-double} is the default in 32 bit mode. + +Modern architectures (Pentium and newer) would prefer @code{long double} +to be aligned to an 8 or 16 byte boundary. In arrays or structures +conforming to the ABI, this would not be possible. So specifying a +@option{-m128bit-long-double} will align @code{long double} +to a 16 byte boundary by padding the @code{long double} with an additional +32 bit zero. + +In the x86-64 compiler, @option{-m128bit-long-double} is the default choice as +its ABI specifies that @code{long double} is to be aligned on 16 byte boundary. + +Notice that neither of these options enable any extra precision over the x87 +standard of 80 bits for a @code{long double}. + +@strong{Warning:} if you override the default value for your target ABI, the +structures and arrays containing @code{long double} variables will change +their size as well as function calling convention for function taking +@code{long double} will be modified. Hence they will not be binary +compatible with arrays or structures in code compiled without that switch. + +@item -mmlarge-data-threshold=@var{number} +@opindex mlarge-data-threshold=@var{number} +When @option{-mcmodel=medium} is specified, the data greater than +@var{threshold} are placed in large data section. This value must be the +same across all object linked into the binary and defaults to 65535. + +@item -msvr3-shlib +@itemx -mno-svr3-shlib +@opindex msvr3-shlib +@opindex mno-svr3-shlib +Control whether GCC places uninitialized local variables into the +@code{bss} or @code{data} segments. @option{-msvr3-shlib} places them +into @code{bss}. These options are meaningful only on System V Release 3. + +@item -mrtd +@opindex mrtd +Use a different function-calling convention, in which functions that +take a fixed number of arguments return with the @code{ret} @var{num} +instruction, which pops their arguments while returning. This saves one +instruction in the caller since there is no need to pop the arguments +there. + +You can specify that an individual function is called with this calling +sequence with the function attribute @samp{stdcall}. You can also +override the @option{-mrtd} option by using the function attribute +@samp{cdecl}. @xref{Function Attributes}. + +@strong{Warning:} this calling convention is incompatible with the one +normally used on Unix, so you cannot use it if you need to call +libraries compiled with the Unix compiler. + +Also, you must provide function prototypes for all functions that +take variable numbers of arguments (including @code{printf}); +otherwise incorrect code will be generated for calls to those +functions. + +In addition, seriously incorrect code will result if you call a +function with too many arguments. (Normally, extra arguments are +harmlessly ignored.) + +@item -mregparm=@var{num} +@opindex mregparm +Control how many registers are used to pass integer arguments. By +default, no registers are used to pass arguments, and at most 3 +registers can be used. You can control this behavior for a specific +function by using the function attribute @samp{regparm}. +@xref{Function Attributes}. + +@strong{Warning:} if you use this switch, and +@var{num} is nonzero, then you must build all modules with the same +value, including any libraries. This includes the system libraries and +startup modules. + +@item -msseregparm +@opindex msseregparm +Use SSE register passing conventions for float and double arguments +and return values. You can control this behavior for a specific +function by using the function attribute @samp{sseregparm}. +@xref{Function Attributes}. + +@strong{Warning:} if you use this switch then you must build all +modules with the same value, including any libraries. This includes +the system libraries and startup modules. + +@item -mstackrealign +@opindex mstackrealign +Realign the stack at entry. On the Intel x86, the +@option{-mstackrealign} option will generate an alternate prologue and +epilogue that realigns the runtime stack. This supports mixing legacy +codes that keep a 4-byte aligned stack with modern codes that keep a +16-byte stack for SSE compatibility. The alternate prologue and +epilogue are slower and bigger than the regular ones, and the +alternate prologue requires an extra scratch register; this lowers the +number of registers available if used in conjunction with the +@code{regparm} attribute. The @option{-mstackrealign} option is +incompatible with the nested function prologue; this is considered a +hard error. See also the attribute @code{force_align_arg_pointer}, +applicable to individual functions. + +@item -mpreferred-stack-boundary=@var{num} +@opindex mpreferred-stack-boundary +Attempt to keep the stack boundary aligned to a 2 raised to @var{num} +byte boundary. If @option{-mpreferred-stack-boundary} is not specified, +the default is 4 (16 bytes or 128 bits). + +On Pentium and PentiumPro, @code{double} and @code{long double} values +should be aligned to an 8 byte boundary (see @option{-malign-double}) or +suffer significant run time performance penalties. On Pentium III, the +Streaming SIMD Extension (SSE) data type @code{__m128} may not work +properly if it is not 16 byte aligned. + +To ensure proper alignment of this values on the stack, the stack boundary +must be as aligned as that required by any value stored on the stack. +Further, every function must be generated such that it keeps the stack +aligned. Thus calling a function compiled with a higher preferred +stack boundary from a function compiled with a lower preferred stack +boundary will most likely misalign the stack. It is recommended that +libraries that use callbacks always use the default setting. + +This extra alignment does consume extra stack space, and generally +increases code size. Code that is sensitive to stack space usage, such +as embedded systems and operating system kernels, may want to reduce the +preferred alignment to @option{-mpreferred-stack-boundary=2}. + +@item -mmmx +@itemx -mno-mmx +@item -msse +@itemx -mno-sse +@item -msse2 +@itemx -mno-sse2 +@item -msse3 +@itemx -mno-sse3 +@c APPLE LOCAL begin mainline +@item -mssse3 +@itemx -mno-ssse3 +@c APPLE LOCAL end mainline +@c APPLE LOCAL begin 5612787 sse4 +@item -msse4.1 +@itemx -mno-sse4.1 +@item -msse4.2 +@itemx -mno-sse4.2 +@item -msse4 +@itemx -mno-sse4 +@item -msse4a +@item -mno-sse4a +@c APPLE LOCAL end 5612787 sse4 +@item -m3dnow +@itemx -mno-3dnow +@opindex mmmx +@opindex mno-mmx +@opindex msse +@opindex mno-sse +@opindex m3dnow +@opindex mno-3dnow +These switches enable or disable the use of instructions in the MMX, +@c APPLE LOCAL begin 5612787 sse4 +SSE, SSE2, SSE3, SSSE3, 3Dnow, SSE4.1, SSE4.2, and SSE4A extended +instruction sets. These extensions are +@c APPLE LOCAL end 5612787 sse4 +also available as built-in functions: see @ref{X86 Built-in Functions}, +for details of the functions enabled and disabled by these switches. + +To have SSE/SSE2 instructions generated automatically from floating-point +code (as opposed to 387 instructions), see @option{-mfpmath=sse}. + +These options will enable GCC to use these extended instructions in +generated code, even without @option{-mfpmath=sse}. Applications which +perform runtime CPU detection must compile separate files for each +supported architecture, using the appropriate flags. In particular, +the file containing the CPU detection code should be compiled without +these options. + +@item -mpush-args +@itemx -mno-push-args +@opindex mpush-args +@opindex mno-push-args +Use PUSH operations to store outgoing parameters. This method is shorter +and usually equally fast as method using SUB/MOV operations and is enabled +by default. In some cases disabling it may improve performance because of +improved scheduling and reduced dependencies. + +@item -maccumulate-outgoing-args +@opindex maccumulate-outgoing-args +If enabled, the maximum amount of space required for outgoing arguments will be +computed in the function prologue. This is faster on most modern CPUs +because of reduced dependencies, improved scheduling and reduced stack usage +when preferred stack boundary is not equal to 2. The drawback is a notable +increase in code size. This switch implies @option{-mno-push-args}. + +@item -mthreads +@opindex mthreads +Support thread-safe exception handling on @samp{Mingw32}. Code that relies +on thread-safe exception handling must compile and link all code with the +@option{-mthreads} option. When compiling, @option{-mthreads} defines +@option{-D_MT}; when linking, it links in a special thread helper library +@option{-lmingwthrd} which cleans up per thread exception handling data. + +@item -mno-align-stringops +@opindex mno-align-stringops +Do not align destination of inlined string operations. This switch reduces +code size and improves performance in case the destination is already aligned, +but GCC doesn't know about it. + +@item -minline-all-stringops +@opindex minline-all-stringops +By default GCC inlines string operations only when destination is known to be +aligned at least to 4 byte boundary. This enables more inlining, increase code +size, but may improve performance of code that depends on fast memcpy, strlen +and memset for short lengths. + +@item -momit-leaf-frame-pointer +@opindex momit-leaf-frame-pointer +Don't keep the frame pointer in a register for leaf functions. This +avoids the instructions to save, set up and restore frame pointers and +makes an extra register available in leaf functions. The option +@option{-fomit-frame-pointer} removes the frame pointer for all functions +which might make debugging harder. + +@item -mtls-direct-seg-refs +@itemx -mno-tls-direct-seg-refs +@opindex mtls-direct-seg-refs +Controls whether TLS variables may be accessed with offsets from the +TLS segment register (@code{%gs} for 32-bit, @code{%fs} for 64-bit), +or whether the thread base pointer must be added. Whether or not this +is legal depends on the operating system, and whether it maps the +segment to cover the entire TLS area. + +For systems that use GNU libc, the default is on. +@end table + +These @samp{-m} switches are supported in addition to the above +on AMD x86-64 processors in 64-bit environments. + +@table @gcctabopt +@item -m32 +@itemx -m64 +@opindex m32 +@opindex m64 +Generate code for a 32-bit or 64-bit environment. +The 32-bit environment sets int, long and pointer to 32 bits and +generates code that runs on any i386 system. +The 64-bit environment sets int to 32 bits and long and pointer +to 64 bits and generates code for AMD's x86-64 architecture. For +darwin only the -m64 option turns off the @option{-fno-pic} and +@option{-mdynamic-no-pic} options. + +@item -mno-red-zone +@opindex no-red-zone +Do not use a so called red zone for x86-64 code. The red zone is mandated +by the x86-64 ABI, it is a 128-byte area beyond the location of the +stack pointer that will not be modified by signal or interrupt handlers +and therefore can be used for temporary data without adjusting the stack +pointer. The flag @option{-mno-red-zone} disables this red zone. + +@item -mcmodel=small +@opindex mcmodel=small +Generate code for the small code model: the program and its symbols must +be linked in the lower 2 GB of the address space. Pointers are 64 bits. +Programs can be statically or dynamically linked. This is the default +code model. + +@item -mcmodel=kernel +@opindex mcmodel=kernel +Generate code for the kernel code model. The kernel runs in the +negative 2 GB of the address space. +This model has to be used for Linux kernel code. + +@item -mcmodel=medium +@opindex mcmodel=medium +Generate code for the medium model: The program is linked in the lower 2 +GB of the address space but symbols can be located anywhere in the +address space. Programs can be statically or dynamically linked, but +building of shared libraries are not supported with the medium model. + +@item -mcmodel=large +@opindex mcmodel=large +Generate code for the large model: This model makes no assumptions +about addresses and sizes of sections. Currently GCC does not implement +this model. + +@c APPLE LOCAL begin 5946347 ms_struct support +@item -mms-bitfields +@opindex mms-bitfields +Set the default structure layout to be compatible with the Microsoft +compiler standard. This is equivalent to adding an @code{ms_struct} +attribute to each structure and union tag definition. The default is +@option{mno-ms-bitfields}. +@c APPLE LOCAL end 5946347 ms_struct support + +@end table + +@c APPLE LOCAL prune man page +@ignore +@node IA-64 Options +@subsection IA-64 Options +@cindex IA-64 Options + +These are the @samp{-m} options defined for the Intel IA-64 architecture. + +@table @gcctabopt +@item -mbig-endian +@opindex mbig-endian +Generate code for a big endian target. This is the default for HP-UX@. + +@item -mlittle-endian +@opindex mlittle-endian +Generate code for a little endian target. This is the default for AIX5 +and GNU/Linux. + +@item -mgnu-as +@itemx -mno-gnu-as +@opindex mgnu-as +@opindex mno-gnu-as +Generate (or don't) code for the GNU assembler. This is the default. +@c Also, this is the default if the configure option @option{--with-gnu-as} +@c is used. + +@item -mgnu-ld +@itemx -mno-gnu-ld +@opindex mgnu-ld +@opindex mno-gnu-ld +Generate (or don't) code for the GNU linker. This is the default. +@c Also, this is the default if the configure option @option{--with-gnu-ld} +@c is used. + +@item -mno-pic +@opindex mno-pic +Generate code that does not use a global pointer register. The result +is not position independent code, and violates the IA-64 ABI@. + +@item -mvolatile-asm-stop +@itemx -mno-volatile-asm-stop +@opindex mvolatile-asm-stop +@opindex mno-volatile-asm-stop +Generate (or don't) a stop bit immediately before and after volatile asm +statements. + +@item -mregister-names +@itemx -mno-register-names +@opindex mregister-names +@opindex mno-register-names +Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for +the stacked registers. This may make assembler output more readable. + +@item -mno-sdata +@itemx -msdata +@opindex mno-sdata +@opindex msdata +Disable (or enable) optimizations that use the small data section. This may +be useful for working around optimizer bugs. + +@item -mconstant-gp +@opindex mconstant-gp +Generate code that uses a single constant global pointer value. This is +useful when compiling kernel code. + +@item -mauto-pic +@opindex mauto-pic +Generate code that is self-relocatable. This implies @option{-mconstant-gp}. +This is useful when compiling firmware code. + +@item -minline-float-divide-min-latency +@opindex minline-float-divide-min-latency +Generate code for inline divides of floating point values +using the minimum latency algorithm. + +@item -minline-float-divide-max-throughput +@opindex minline-float-divide-max-throughput +Generate code for inline divides of floating point values +using the maximum throughput algorithm. + +@item -minline-int-divide-min-latency +@opindex minline-int-divide-min-latency +Generate code for inline divides of integer values +using the minimum latency algorithm. + +@item -minline-int-divide-max-throughput +@opindex minline-int-divide-max-throughput +Generate code for inline divides of integer values +using the maximum throughput algorithm. + +@item -minline-sqrt-min-latency +@opindex minline-sqrt-min-latency +Generate code for inline square roots +using the minimum latency algorithm. + +@item -minline-sqrt-max-throughput +@opindex minline-sqrt-max-throughput +Generate code for inline square roots +using the maximum throughput algorithm. + +@item -mno-dwarf2-asm +@itemx -mdwarf2-asm +@opindex mno-dwarf2-asm +@opindex mdwarf2-asm +Don't (or do) generate assembler code for the DWARF2 line number debugging +info. This may be useful when not using the GNU assembler. + +@item -mearly-stop-bits +@itemx -mno-early-stop-bits +@opindex mearly-stop-bits +@opindex mno-early-stop-bits +Allow stop bits to be placed earlier than immediately preceding the +instruction that triggered the stop bit. This can improve instruction +scheduling, but does not always do so. + +@item -mfixed-range=@var{register-range} +@opindex mfixed-range +Generate code treating the given register range as fixed registers. +A fixed register is one that the register allocator can not use. This is +useful when compiling kernel code. A register range is specified as +two registers separated by a dash. Multiple register ranges can be +specified separated by a comma. + +@item -mtls-size=@var{tls-size} +@opindex mtls-size +Specify bit size of immediate TLS offsets. Valid values are 14, 22, and +64. + +@item -mtune=@var{cpu-type} +@opindex mtune +Tune the instruction scheduling for a particular CPU, Valid values are +itanium, itanium1, merced, itanium2, and mckinley. + +@item -mt +@itemx -pthread +@opindex mt +@opindex pthread +Add support for multithreading using the POSIX threads library. This +option sets flags for both the preprocessor and linker. It does +not affect the thread safety of object code produced by the compiler or +that of libraries supplied with it. These are HP-UX specific flags. + +@item -milp32 +@itemx -mlp64 +@opindex milp32 +@opindex mlp64 +Generate code for a 32-bit or 64-bit environment. +The 32-bit environment sets int, long and pointer to 32 bits. +The 64-bit environment sets int to 32 bits and long and pointer +to 64 bits. These are HP-UX specific flags. + +@item -mno-sched-br-data-spec +@itemx -msched-br-data-spec +@opindex mno-sched-br-data-spec +@opindex msched-br-data-spec +(Dis/En)able data speculative scheduling before reload. +This will result in generation of the ld.a instructions and +the corresponding check instructions (ld.c / chk.a). +The default is 'disable'. + +@item -msched-ar-data-spec +@itemx -mno-sched-ar-data-spec +@opindex msched-ar-data-spec +@opindex mno-sched-ar-data-spec +(En/Dis)able data speculative scheduling after reload. +This will result in generation of the ld.a instructions and +the corresponding check instructions (ld.c / chk.a). +The default is 'enable'. + +@item -mno-sched-control-spec +@itemx -msched-control-spec +@opindex mno-sched-control-spec +@opindex msched-control-spec +(Dis/En)able control speculative scheduling. This feature is +available only during region scheduling (i.e. before reload). +This will result in generation of the ld.s instructions and +the corresponding check instructions chk.s . +The default is 'disable'. + +@item -msched-br-in-data-spec +@itemx -mno-sched-br-in-data-spec +@opindex msched-br-in-data-spec +@opindex mno-sched-br-in-data-spec +(En/Dis)able speculative scheduling of the instructions that +are dependent on the data speculative loads before reload. +This is effective only with @option{-msched-br-data-spec} enabled. +The default is 'enable'. + +@item -msched-ar-in-data-spec +@itemx -mno-sched-ar-in-data-spec +@opindex msched-ar-in-data-spec +@opindex mno-sched-ar-in-data-spec +(En/Dis)able speculative scheduling of the instructions that +are dependent on the data speculative loads after reload. +This is effective only with @option{-msched-ar-data-spec} enabled. +The default is 'enable'. + +@item -msched-in-control-spec +@itemx -mno-sched-in-control-spec +@opindex msched-in-control-spec +@opindex mno-sched-in-control-spec +(En/Dis)able speculative scheduling of the instructions that +are dependent on the control speculative loads. +This is effective only with @option{-msched-control-spec} enabled. +The default is 'enable'. + +@item -msched-ldc +@itemx -mno-sched-ldc +@opindex msched-ldc +@opindex mno-sched-ldc +(En/Dis)able use of simple data speculation checks ld.c . +If disabled, only chk.a instructions will be emitted to check +data speculative loads. +The default is 'enable'. + +@item -mno-sched-control-ldc +@itemx -msched-control-ldc +@opindex mno-sched-control-ldc +@opindex msched-control-ldc +(Dis/En)able use of ld.c instructions to check control speculative loads. +If enabled, in case of control speculative load with no speculatively +scheduled dependent instructions this load will be emitted as ld.sa and +ld.c will be used to check it. +The default is 'disable'. + +@item -mno-sched-spec-verbose +@itemx -msched-spec-verbose +@opindex mno-sched-spec-verbose +@opindex msched-spec-verbose +(Dis/En)able printing of the information about speculative motions. + +@item -mno-sched-prefer-non-data-spec-insns +@itemx -msched-prefer-non-data-spec-insns +@opindex mno-sched-prefer-non-data-spec-insns +@opindex msched-prefer-non-data-spec-insns +If enabled, data speculative instructions will be chosen for schedule +only if there are no other choices at the moment. This will make +the use of the data speculation much more conservative. +The default is 'disable'. + +@item -mno-sched-prefer-non-control-spec-insns +@itemx -msched-prefer-non-control-spec-insns +@opindex mno-sched-prefer-non-control-spec-insns +@opindex msched-prefer-non-control-spec-insns +If enabled, control speculative instructions will be chosen for schedule +only if there are no other choices at the moment. This will make +the use of the control speculation much more conservative. +The default is 'disable'. + +@item -mno-sched-count-spec-in-critical-path +@itemx -msched-count-spec-in-critical-path +@opindex mno-sched-count-spec-in-critical-path +@opindex msched-count-spec-in-critical-path +If enabled, speculative dependencies will be considered during +computation of the instructions priorities. This will make the use of the +speculation a bit more conservative. +The default is 'disable'. + +@end table + +@node M32C Options +@subsection M32C Options +@cindex M32C options + +@table @gcctabopt +@item -mcpu=@var{name} +@opindex mcpu= +Select the CPU for which code is generated. @var{name} may be one of +@samp{r8c} for the R8C/Tiny series, @samp{m16c} for the M16C (up to +/60) series, @samp{m32cm} for the M16C/80 series, or @samp{m32c} for +the M32C/80 series. + +@item -msim +@opindex msim +Specifies that the program will be run on the simulator. This causes +an alternate runtime library to be linked in which supports, for +example, file I/O. You must not use this option when generating +programs that will run on real hardware; you must provide your own +runtime library for whatever I/O functions are needed. + +@item -memregs=@var{number} +@opindex memregs= +Specifies the number of memory-based pseudo-registers GCC will use +during code generation. These pseudo-registers will be used like real +registers, so there is a tradeoff between GCC's ability to fit the +code into available registers, and the performance penalty of using +memory instead of registers. Note that all modules in a program must +be compiled with the same value for this option. Because of that, you +must not use this option with the default runtime libraries gcc +builds. + +@end table + +@node M32R/D Options +@subsection M32R/D Options +@cindex M32R/D options + +These @option{-m} options are defined for Renesas M32R/D architectures: + +@table @gcctabopt +@item -m32r2 +@opindex m32r2 +Generate code for the M32R/2@. + +@item -m32rx +@opindex m32rx +Generate code for the M32R/X@. + +@item -m32r +@opindex m32r +Generate code for the M32R@. This is the default. + +@item -mmodel=small +@opindex mmodel=small +Assume all objects live in the lower 16MB of memory (so that their addresses +can be loaded with the @code{ld24} instruction), and assume all subroutines +are reachable with the @code{bl} instruction. +This is the default. + +The addressability of a particular object can be set with the +@code{model} attribute. + +@item -mmodel=medium +@opindex mmodel=medium +Assume objects may be anywhere in the 32-bit address space (the compiler +will generate @code{seth/add3} instructions to load their addresses), and +assume all subroutines are reachable with the @code{bl} instruction. + +@item -mmodel=large +@opindex mmodel=large +Assume objects may be anywhere in the 32-bit address space (the compiler +will generate @code{seth/add3} instructions to load their addresses), and +assume subroutines may not be reachable with the @code{bl} instruction +(the compiler will generate the much slower @code{seth/add3/jl} +instruction sequence). + +@item -msdata=none +@opindex msdata=none +Disable use of the small data area. Variables will be put into +one of @samp{.data}, @samp{bss}, or @samp{.rodata} (unless the +@code{section} attribute has been specified). +This is the default. + +The small data area consists of sections @samp{.sdata} and @samp{.sbss}. +Objects may be explicitly put in the small data area with the +@code{section} attribute using one of these sections. + +@item -msdata=sdata +@opindex msdata=sdata +Put small global and static data in the small data area, but do not +generate special code to reference them. + +@item -msdata=use +@opindex msdata=use +Put small global and static data in the small data area, and generate +special instructions to reference them. + +@item -G @var{num} +@opindex G +@cindex smaller data references +Put global and static objects less than or equal to @var{num} bytes +into the small data or bss sections instead of the normal data or bss +sections. The default value of @var{num} is 8. +The @option{-msdata} option must be set to one of @samp{sdata} or @samp{use} +for this option to have any effect. + +All modules should be compiled with the same @option{-G @var{num}} value. +Compiling with different values of @var{num} may or may not work; if it +doesn't the linker will give an error message---incorrect code will not be +generated. + +@item -mdebug +@opindex mdebug +Makes the M32R specific code in the compiler display some statistics +that might help in debugging programs. + +@item -malign-loops +@opindex malign-loops +Align all loops to a 32-byte boundary. + +@item -mno-align-loops +@opindex mno-align-loops +Do not enforce a 32-byte alignment for loops. This is the default. + +@item -missue-rate=@var{number} +@opindex missue-rate=@var{number} +Issue @var{number} instructions per cycle. @var{number} can only be 1 +or 2. + +@item -mbranch-cost=@var{number} +@opindex mbranch-cost=@var{number} +@var{number} can only be 1 or 2. If it is 1 then branches will be +preferred over conditional code, if it is 2, then the opposite will +apply. + +@item -mflush-trap=@var{number} +@opindex mflush-trap=@var{number} +Specifies the trap number to use to flush the cache. The default is +12. Valid numbers are between 0 and 15 inclusive. + +@item -mno-flush-trap +@opindex mno-flush-trap +Specifies that the cache cannot be flushed by using a trap. + +@item -mflush-func=@var{name} +@opindex mflush-func=@var{name} +Specifies the name of the operating system function to call to flush +the cache. The default is @emph{_flush_cache}, but a function call +will only be used if a trap is not available. + +@item -mno-flush-func +@opindex mno-flush-func +Indicates that there is no OS function for flushing the cache. + +@end table + +@node M680x0 Options +@subsection M680x0 Options +@cindex M680x0 options + +These are the @samp{-m} options defined for the 68000 series. The default +values for these options depends on which style of 68000 was selected when +the compiler was configured; the defaults for the most common choices are +given below. + +@table @gcctabopt +@item -m68000 +@itemx -mc68000 +@opindex m68000 +@opindex mc68000 +Generate output for a 68000. This is the default +when the compiler is configured for 68000-based systems. + +Use this option for microcontrollers with a 68000 or EC000 core, +including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356. + +@item -m68020 +@itemx -mc68020 +@opindex m68020 +@opindex mc68020 +Generate output for a 68020. This is the default +when the compiler is configured for 68020-based systems. + +@item -m68881 +@opindex m68881 +Generate output containing 68881 instructions for floating point. +This is the default for most 68020 systems unless @option{--nfp} was +specified when the compiler was configured. + +@item -m68030 +@opindex m68030 +Generate output for a 68030. This is the default when the compiler is +configured for 68030-based systems. + +@item -m68040 +@opindex m68040 +Generate output for a 68040. This is the default when the compiler is +configured for 68040-based systems. + +This option inhibits the use of 68881/68882 instructions that have to be +emulated by software on the 68040. Use this option if your 68040 does not +have code to emulate those instructions. + +@item -m68060 +@opindex m68060 +Generate output for a 68060. This is the default when the compiler is +configured for 68060-based systems. + +This option inhibits the use of 68020 and 68881/68882 instructions that +have to be emulated by software on the 68060. Use this option if your 68060 +does not have code to emulate those instructions. + +@item -mcpu32 +@opindex mcpu32 +Generate output for a CPU32. This is the default +when the compiler is configured for CPU32-based systems. + +Use this option for microcontrollers with a +CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334, +68336, 68340, 68341, 68349 and 68360. + +@item -m5200 +@opindex m5200 +Generate output for a 520X ``coldfire'' family cpu. This is the default +when the compiler is configured for 520X-based systems. + +Use this option for microcontroller with a 5200 core, including +the MCF5202, MCF5203, MCF5204 and MCF5202. + +@item -mcfv4e +@opindex mcfv4e +Generate output for a ColdFire V4e family cpu (e.g.@: 547x/548x). +This includes use of hardware floating point instructions. + +@item -m68020-40 +@opindex m68020-40 +Generate output for a 68040, without using any of the new instructions. +This results in code which can run relatively efficiently on either a +68020/68881 or a 68030 or a 68040. The generated code does use the +68881 instructions that are emulated on the 68040. + +@item -m68020-60 +@opindex m68020-60 +Generate output for a 68060, without using any of the new instructions. +This results in code which can run relatively efficiently on either a +68020/68881 or a 68030 or a 68040. The generated code does use the +68881 instructions that are emulated on the 68060. + +@item -msoft-float +@opindex msoft-float +Generate output containing library calls for floating point. +@strong{Warning:} the requisite libraries are not available for all m68k +targets. Normally the facilities of the machine's usual C compiler are +used, but this can't be done directly in cross-compilation. You must +make your own arrangements to provide suitable library functions for +cross-compilation. The embedded targets @samp{m68k-*-aout} and +@samp{m68k-*-coff} do provide software floating point support. + +@item -mshort +@opindex mshort +Consider type @code{int} to be 16 bits wide, like @code{short int}. +Additionally, parameters passed on the stack are also aligned to a +16-bit boundary even on targets whose API mandates promotion to 32-bit. + +@item -mnobitfield +@opindex mnobitfield +Do not use the bit-field instructions. The @option{-m68000}, @option{-mcpu32} +and @option{-m5200} options imply @w{@option{-mnobitfield}}. + +@item -mbitfield +@opindex mbitfield +Do use the bit-field instructions. The @option{-m68020} option implies +@option{-mbitfield}. This is the default if you use a configuration +designed for a 68020. + +@item -mrtd +@opindex mrtd +Use a different function-calling convention, in which functions +that take a fixed number of arguments return with the @code{rtd} +instruction, which pops their arguments while returning. This +saves one instruction in the caller since there is no need to pop +the arguments there. + +This calling convention is incompatible with the one normally +used on Unix, so you cannot use it if you need to call libraries +compiled with the Unix compiler. + +Also, you must provide function prototypes for all functions that +take variable numbers of arguments (including @code{printf}); +otherwise incorrect code will be generated for calls to those +functions. + +In addition, seriously incorrect code will result if you call a +function with too many arguments. (Normally, extra arguments are +harmlessly ignored.) + +The @code{rtd} instruction is supported by the 68010, 68020, 68030, +68040, 68060 and CPU32 processors, but not by the 68000 or 5200. + +@item -malign-int +@itemx -mno-align-int +@opindex malign-int +@opindex mno-align-int +Control whether GCC aligns @code{int}, @code{long}, @code{long long}, +@code{float}, @code{double}, and @code{long double} variables on a 32-bit +boundary (@option{-malign-int}) or a 16-bit boundary (@option{-mno-align-int}). +Aligning variables on 32-bit boundaries produces code that runs somewhat +faster on processors with 32-bit busses at the expense of more memory. + +@strong{Warning:} if you use the @option{-malign-int} switch, GCC will +align structures containing the above types differently than +most published application binary interface specifications for the m68k. + +@item -mpcrel +@opindex mpcrel +Use the pc-relative addressing mode of the 68000 directly, instead of +using a global offset table. At present, this option implies @option{-fpic}, +allowing at most a 16-bit offset for pc-relative addressing. @option{-fPIC} is +not presently supported with @option{-mpcrel}, though this could be supported for +68020 and higher processors. + +@item -mno-strict-align +@itemx -mstrict-align +@opindex mno-strict-align +@opindex mstrict-align +Do not (do) assume that unaligned memory references will be handled by +the system. + +@item -msep-data +Generate code that allows the data segment to be located in a different +area of memory from the text segment. This allows for execute in place in +an environment without virtual memory management. This option implies +@option{-fPIC}. + +@item -mno-sep-data +Generate code that assumes that the data segment follows the text segment. +This is the default. + +@item -mid-shared-library +Generate code that supports shared libraries via the library ID method. +This allows for execute in place and shared libraries in an environment +without virtual memory management. This option implies @option{-fPIC}. + +@item -mno-id-shared-library +Generate code that doesn't assume ID based shared libraries are being used. +This is the default. + +@item -mshared-library-id=n +Specified the identification number of the ID based shared library being +compiled. Specifying a value of 0 will generate more compact code, specifying +other values will force the allocation of that number to the current +library but is no more space or time efficient than omitting this option. + +@end table + +@node M68hc1x Options +@subsection M68hc1x Options +@cindex M68hc1x options + +These are the @samp{-m} options defined for the 68hc11 and 68hc12 +microcontrollers. The default values for these options depends on +which style of microcontroller was selected when the compiler was configured; +the defaults for the most common choices are given below. + +@table @gcctabopt +@item -m6811 +@itemx -m68hc11 +@opindex m6811 +@opindex m68hc11 +Generate output for a 68HC11. This is the default +when the compiler is configured for 68HC11-based systems. + +@item -m6812 +@itemx -m68hc12 +@opindex m6812 +@opindex m68hc12 +Generate output for a 68HC12. This is the default +when the compiler is configured for 68HC12-based systems. + +@item -m68S12 +@itemx -m68hcs12 +@opindex m68S12 +@opindex m68hcs12 +Generate output for a 68HCS12. + +@item -mauto-incdec +@opindex mauto-incdec +Enable the use of 68HC12 pre and post auto-increment and auto-decrement +addressing modes. + +@item -minmax +@itemx -nominmax +@opindex minmax +@opindex mnominmax +Enable the use of 68HC12 min and max instructions. + +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Treat all calls as being far away (near). If calls are assumed to be +far away, the compiler will use the @code{call} instruction to +call a function and the @code{rtc} instruction for returning. + +@item -mshort +@opindex mshort +Consider type @code{int} to be 16 bits wide, like @code{short int}. + +@item -msoft-reg-count=@var{count} +@opindex msoft-reg-count +Specify the number of pseudo-soft registers which are used for the +code generation. The maximum number is 32. Using more pseudo-soft +register may or may not result in better code depending on the program. +The default is 4 for 68HC11 and 2 for 68HC12. + +@end table + +@node MCore Options +@subsection MCore Options +@cindex MCore options + +These are the @samp{-m} options defined for the Motorola M*Core +processors. + +@table @gcctabopt + +@item -mhardlit +@itemx -mno-hardlit +@opindex mhardlit +@opindex mno-hardlit +Inline constants into the code stream if it can be done in two +instructions or less. + +@item -mdiv +@itemx -mno-div +@opindex mdiv +@opindex mno-div +Use the divide instruction. (Enabled by default). + +@item -mrelax-immediate +@itemx -mno-relax-immediate +@opindex mrelax-immediate +@opindex mno-relax-immediate +Allow arbitrary sized immediates in bit operations. + +@item -mwide-bitfields +@itemx -mno-wide-bitfields +@opindex mwide-bitfields +@opindex mno-wide-bitfields +Always treat bit-fields as int-sized. + +@item -m4byte-functions +@itemx -mno-4byte-functions +@opindex m4byte-functions +@opindex mno-4byte-functions +Force all functions to be aligned to a four byte boundary. + +@item -mcallgraph-data +@itemx -mno-callgraph-data +@opindex mcallgraph-data +@opindex mno-callgraph-data +Emit callgraph information. + +@item -mslow-bytes +@itemx -mno-slow-bytes +@opindex mslow-bytes +@opindex mno-slow-bytes +Prefer word access when reading byte quantities. + +@item -mlittle-endian +@itemx -mbig-endian +@opindex mlittle-endian +@opindex mbig-endian +Generate code for a little endian target. + +@item -m210 +@itemx -m340 +@opindex m210 +@opindex m340 +Generate code for the 210 processor. +@end table + +@node MIPS Options +@subsection MIPS Options +@cindex MIPS options + +@table @gcctabopt + +@item -EB +@opindex EB +Generate big-endian code. + +@item -EL +@opindex EL +Generate little-endian code. This is the default for @samp{mips*el-*-*} +configurations. + +@item -march=@var{arch} +@opindex march +Generate code that will run on @var{arch}, which can be the name of a +generic MIPS ISA, or the name of a particular processor. +The ISA names are: +@samp{mips1}, @samp{mips2}, @samp{mips3}, @samp{mips4}, +@samp{mips32}, @samp{mips32r2}, and @samp{mips64}. +The processor names are: +@samp{4kc}, @samp{4km}, @samp{4kp}, +@samp{5kc}, @samp{5kf}, +@samp{20kc}, +@samp{24k}, @samp{24kc}, @samp{24kf}, @samp{24kx}, +@samp{m4k}, +@samp{orion}, +@samp{r2000}, @samp{r3000}, @samp{r3900}, @samp{r4000}, @samp{r4400}, +@samp{r4600}, @samp{r4650}, @samp{r6000}, @samp{r8000}, +@samp{rm7000}, @samp{rm9000}, +@samp{sb1}, +@samp{sr71000}, +@samp{vr4100}, @samp{vr4111}, @samp{vr4120}, @samp{vr4130}, @samp{vr4300}, +@samp{vr5000}, @samp{vr5400} and @samp{vr5500}. +The special value @samp{from-abi} selects the +most compatible architecture for the selected ABI (that is, +@samp{mips1} for 32-bit ABIs and @samp{mips3} for 64-bit ABIs)@. + +In processor names, a final @samp{000} can be abbreviated as @samp{k} +(for example, @samp{-march=r2k}). Prefixes are optional, and +@samp{vr} may be written @samp{r}. + +GCC defines two macros based on the value of this option. The first +is @samp{_MIPS_ARCH}, which gives the name of target architecture, as +a string. The second has the form @samp{_MIPS_ARCH_@var{foo}}, +where @var{foo} is the capitalized value of @samp{_MIPS_ARCH}@. +For example, @samp{-march=r2000} will set @samp{_MIPS_ARCH} +to @samp{"r2000"} and define the macro @samp{_MIPS_ARCH_R2000}. + +Note that the @samp{_MIPS_ARCH} macro uses the processor names given +above. In other words, it will have the full prefix and will not +abbreviate @samp{000} as @samp{k}. In the case of @samp{from-abi}, +the macro names the resolved architecture (either @samp{"mips1"} or +@samp{"mips3"}). It names the default architecture when no +@option{-march} option is given. + +@item -mtune=@var{arch} +@opindex mtune +Optimize for @var{arch}. Among other things, this option controls +the way instructions are scheduled, and the perceived cost of arithmetic +operations. The list of @var{arch} values is the same as for +@option{-march}. + +When this option is not used, GCC will optimize for the processor +specified by @option{-march}. By using @option{-march} and +@option{-mtune} together, it is possible to generate code that will +run on a family of processors, but optimize the code for one +particular member of that family. + +@samp{-mtune} defines the macros @samp{_MIPS_TUNE} and +@samp{_MIPS_TUNE_@var{foo}}, which work in the same way as the +@samp{-march} ones described above. + +@item -mips1 +@opindex mips1 +Equivalent to @samp{-march=mips1}. + +@item -mips2 +@opindex mips2 +Equivalent to @samp{-march=mips2}. + +@item -mips3 +@opindex mips3 +Equivalent to @samp{-march=mips3}. + +@item -mips4 +@opindex mips4 +Equivalent to @samp{-march=mips4}. + +@item -mips32 +@opindex mips32 +Equivalent to @samp{-march=mips32}. + +@item -mips32r2 +@opindex mips32r2 +Equivalent to @samp{-march=mips32r2}. + +@item -mips64 +@opindex mips64 +Equivalent to @samp{-march=mips64}. + +@item -mips16 +@itemx -mno-mips16 +@opindex mips16 +@opindex mno-mips16 +Generate (do not generate) MIPS16 code. If GCC is targetting a +MIPS32 or MIPS64 architecture, it will make use of the MIPS16e ASE@. + +@item -mabi=32 +@itemx -mabi=o64 +@itemx -mabi=n32 +@itemx -mabi=64 +@itemx -mabi=eabi +@opindex mabi=32 +@opindex mabi=o64 +@opindex mabi=n32 +@opindex mabi=64 +@opindex mabi=eabi +Generate code for the given ABI@. + +Note that the EABI has a 32-bit and a 64-bit variant. GCC normally +generates 64-bit code when you select a 64-bit architecture, but you +can use @option{-mgp32} to get 32-bit code instead. + +For information about the O64 ABI, see +@w{@uref{http://gcc.gnu.org/projects/mipso64-abi.html}}. + +@item -mabicalls +@itemx -mno-abicalls +@opindex mabicalls +@opindex mno-abicalls +Generate (do not generate) code that is suitable for SVR4-style +dynamic objects. @option{-mabicalls} is the default for SVR4-based +systems. + +@item -mshared +@itemx -mno-shared +Generate (do not generate) code that is fully position-independent, +and that can therefore be linked into shared libraries. This option +only affects @option{-mabicalls}. + +All @option{-mabicalls} code has traditionally been position-independent, +regardless of options like @option{-fPIC} and @option{-fpic}. However, +as an extension, the GNU toolchain allows executables to use absolute +accesses for locally-binding symbols. It can also use shorter GP +initialization sequences and generate direct calls to locally-defined +functions. This mode is selected by @option{-mno-shared}. + +@option{-mno-shared} depends on binutils 2.16 or higher and generates +objects that can only be linked by the GNU linker. However, the option +does not affect the ABI of the final executable; it only affects the ABI +of relocatable objects. Using @option{-mno-shared} will generally make +executables both smaller and quicker. + +@option{-mshared} is the default. + +@item -mxgot +@itemx -mno-xgot +@opindex mxgot +@opindex mno-xgot +Lift (do not lift) the usual restrictions on the size of the global +offset table. + +GCC normally uses a single instruction to load values from the GOT@. +While this is relatively efficient, it will only work if the GOT +is smaller than about 64k. Anything larger will cause the linker +to report an error such as: + +@cindex relocation truncated to fit (MIPS) +@smallexample +relocation truncated to fit: R_MIPS_GOT16 foobar +@end smallexample + +If this happens, you should recompile your code with @option{-mxgot}. +It should then work with very large GOTs, although it will also be +less efficient, since it will take three instructions to fetch the +value of a global symbol. + +Note that some linkers can create multiple GOTs. If you have such a +linker, you should only need to use @option{-mxgot} when a single object +file accesses more than 64k's worth of GOT entries. Very few do. + +These options have no effect unless GCC is generating position +independent code. + +@item -mgp32 +@opindex mgp32 +Assume that general-purpose registers are 32 bits wide. + +@item -mgp64 +@opindex mgp64 +Assume that general-purpose registers are 64 bits wide. + +@item -mfp32 +@opindex mfp32 +Assume that floating-point registers are 32 bits wide. + +@item -mfp64 +@opindex mfp64 +Assume that floating-point registers are 64 bits wide. + +@item -mhard-float +@opindex mhard-float +Use floating-point coprocessor instructions. + +@item -msoft-float +@opindex msoft-float +Do not use floating-point coprocessor instructions. Implement +floating-point calculations using library calls instead. + +@item -msingle-float +@opindex msingle-float +Assume that the floating-point coprocessor only supports single-precision +operations. + +@itemx -mdouble-float +@opindex mdouble-float +Assume that the floating-point coprocessor supports double-precision +operations. This is the default. + +@itemx -mdsp +@itemx -mno-dsp +@opindex mdsp +@opindex mno-dsp +Use (do not use) the MIPS DSP ASE. @xref{MIPS DSP Built-in Functions}. + +@itemx -mpaired-single +@itemx -mno-paired-single +@opindex mpaired-single +@opindex mno-paired-single +Use (do not use) paired-single floating-point instructions. +@xref{MIPS Paired-Single Support}. This option can only be used +when generating 64-bit code and requires hardware floating-point +support to be enabled. + +@itemx -mips3d +@itemx -mno-mips3d +@opindex mips3d +@opindex mno-mips3d +Use (do not use) the MIPS-3D ASE@. @xref{MIPS-3D Built-in Functions}. +The option @option{-mips3d} implies @option{-mpaired-single}. + +@item -mlong64 +@opindex mlong64 +Force @code{long} types to be 64 bits wide. See @option{-mlong32} for +an explanation of the default and the way that the pointer size is +determined. + +@item -mlong32 +@opindex mlong32 +Force @code{long}, @code{int}, and pointer types to be 32 bits wide. + +The default size of @code{int}s, @code{long}s and pointers depends on +the ABI@. All the supported ABIs use 32-bit @code{int}s. The n64 ABI +uses 64-bit @code{long}s, as does the 64-bit EABI; the others use +32-bit @code{long}s. Pointers are the same size as @code{long}s, +or the same size as integer registers, whichever is smaller. + +@item -msym32 +@itemx -mno-sym32 +@opindex msym32 +@opindex mno-sym32 +Assume (do not assume) that all symbols have 32-bit values, regardless +of the selected ABI@. This option is useful in combination with +@option{-mabi=64} and @option{-mno-abicalls} because it allows GCC +to generate shorter and faster references to symbolic addresses. + +@item -G @var{num} +@opindex G +@cindex smaller data references (MIPS) +@cindex gp-relative references (MIPS) +Put global and static items less than or equal to @var{num} bytes into +the small data or bss section instead of the normal data or bss section. +This allows the data to be accessed using a single instruction. + +All modules should be compiled with the same @option{-G @var{num}} +value. + +@item -membedded-data +@itemx -mno-embedded-data +@opindex membedded-data +@opindex mno-embedded-data +Allocate variables to the read-only data section first if possible, then +next in the small data section if possible, otherwise in data. This gives +slightly slower code than the default, but reduces the amount of RAM required +when executing, and thus may be preferred for some embedded systems. + +@item -muninit-const-in-rodata +@itemx -mno-uninit-const-in-rodata +@opindex muninit-const-in-rodata +@opindex mno-uninit-const-in-rodata +Put uninitialized @code{const} variables in the read-only data section. +This option is only meaningful in conjunction with @option{-membedded-data}. + +@item -msplit-addresses +@itemx -mno-split-addresses +@opindex msplit-addresses +@opindex mno-split-addresses +Enable (disable) use of the @code{%hi()} and @code{%lo()} assembler +relocation operators. This option has been superseded by +@option{-mexplicit-relocs} but is retained for backwards compatibility. + +@item -mexplicit-relocs +@itemx -mno-explicit-relocs +@opindex mexplicit-relocs +@opindex mno-explicit-relocs +Use (do not use) assembler relocation operators when dealing with symbolic +addresses. The alternative, selected by @option{-mno-explicit-relocs}, +is to use assembler macros instead. + +@option{-mexplicit-relocs} is the default if GCC was configured +to use an assembler that supports relocation operators. + +@item -mcheck-zero-division +@itemx -mno-check-zero-division +@opindex mcheck-zero-division +@opindex mno-check-zero-division +Trap (do not trap) on integer division by zero. The default is +@option{-mcheck-zero-division}. + +@item -mdivide-traps +@itemx -mdivide-breaks +@opindex mdivide-traps +@opindex mdivide-breaks +MIPS systems check for division by zero by generating either a +conditional trap or a break instruction. Using traps results in +smaller code, but is only supported on MIPS II and later. Also, some +versions of the Linux kernel have a bug that prevents trap from +generating the proper signal (@code{SIGFPE}). Use @option{-mdivide-traps} to +allow conditional traps on architectures that support them and +@option{-mdivide-breaks} to force the use of breaks. + +The default is usually @option{-mdivide-traps}, but this can be +overridden at configure time using @option{--with-divide=breaks}. +Divide-by-zero checks can be completely disabled using +@option{-mno-check-zero-division}. + +@item -mmemcpy +@itemx -mno-memcpy +@opindex mmemcpy +@opindex mno-memcpy +Force (do not force) the use of @code{memcpy()} for non-trivial block +moves. The default is @option{-mno-memcpy}, which allows GCC to inline +most constant-sized copies. + +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Disable (do not disable) use of the @code{jal} instruction. Calling +functions using @code{jal} is more efficient but requires the caller +and callee to be in the same 256 megabyte segment. + +This option has no effect on abicalls code. The default is +@option{-mno-long-calls}. + +@item -mmad +@itemx -mno-mad +@opindex mmad +@opindex mno-mad +Enable (disable) use of the @code{mad}, @code{madu} and @code{mul} +instructions, as provided by the R4650 ISA@. + +@item -mfused-madd +@itemx -mno-fused-madd +@opindex mfused-madd +@opindex mno-fused-madd +Enable (disable) use of the floating point multiply-accumulate +instructions, when they are available. The default is +@option{-mfused-madd}. + +When multiply-accumulate instructions are used, the intermediate +product is calculated to infinite precision and is not subject to +the FCSR Flush to Zero bit. This may be undesirable in some +circumstances. + +@item -nocpp +@opindex nocpp +Tell the MIPS assembler to not run its preprocessor over user +assembler files (with a @samp{.s} suffix) when assembling them. + +@item -mfix-r4000 +@itemx -mno-fix-r4000 +@opindex mfix-r4000 +@opindex mno-fix-r4000 +Work around certain R4000 CPU errata: +@itemize @minus +@item +A double-word or a variable shift may give an incorrect result if executed +immediately after starting an integer division. +@item +A double-word or a variable shift may give an incorrect result if executed +while an integer multiplication is in progress. +@item +An integer division may give an incorrect result if started in a delay slot +of a taken branch or a jump. +@end itemize + +@item -mfix-r4400 +@itemx -mno-fix-r4400 +@opindex mfix-r4400 +@opindex mno-fix-r4400 +Work around certain R4400 CPU errata: +@itemize @minus +@item +A double-word or a variable shift may give an incorrect result if executed +immediately after starting an integer division. +@end itemize + +@item -mfix-vr4120 +@itemx -mno-fix-vr4120 +@opindex mfix-vr4120 +Work around certain VR4120 errata: +@itemize @minus +@item +@code{dmultu} does not always produce the correct result. +@item +@code{div} and @code{ddiv} do not always produce the correct result if one +of the operands is negative. +@end itemize +The workarounds for the division errata rely on special functions in +@file{libgcc.a}. At present, these functions are only provided by +the @code{mips64vr*-elf} configurations. + +Other VR4120 errata require a nop to be inserted between certain pairs of +instructions. These errata are handled by the assembler, not by GCC itself. + +@item -mfix-vr4130 +@opindex mfix-vr4130 +Work around the VR4130 @code{mflo}/@code{mfhi} errata. The +workarounds are implemented by the assembler rather than by GCC, +although GCC will avoid using @code{mflo} and @code{mfhi} if the +VR4130 @code{macc}, @code{macchi}, @code{dmacc} and @code{dmacchi} +instructions are available instead. + +@item -mfix-sb1 +@itemx -mno-fix-sb1 +@opindex mfix-sb1 +Work around certain SB-1 CPU core errata. +(This flag currently works around the SB-1 revision 2 +``F1'' and ``F2'' floating point errata.) + +@item -mflush-func=@var{func} +@itemx -mno-flush-func +@opindex mflush-func +Specifies the function to call to flush the I and D caches, or to not +call any such function. If called, the function must take the same +arguments as the common @code{_flush_func()}, that is, the address of the +memory range for which the cache is being flushed, the size of the +memory range, and the number 3 (to flush both caches). The default +depends on the target GCC was configured for, but commonly is either +@samp{_flush_func} or @samp{__cpu_flush}. + +@item -mbranch-likely +@itemx -mno-branch-likely +@opindex mbranch-likely +@opindex mno-branch-likely +Enable or disable use of Branch Likely instructions, regardless of the +default for the selected architecture. By default, Branch Likely +instructions may be generated if they are supported by the selected +architecture. An exception is for the MIPS32 and MIPS64 architectures +and processors which implement those architectures; for those, Branch +Likely instructions will not be generated by default because the MIPS32 +and MIPS64 architectures specifically deprecate their use. + +@item -mfp-exceptions +@itemx -mno-fp-exceptions +@opindex mfp-exceptions +Specifies whether FP exceptions are enabled. This affects how we schedule +FP instructions for some processors. The default is that FP exceptions are +enabled. + +For instance, on the SB-1, if FP exceptions are disabled, and we are emitting +64-bit code, then we can use both FP pipes. Otherwise, we can only use one +FP pipe. + +@item -mvr4130-align +@itemx -mno-vr4130-align +@opindex mvr4130-align +The VR4130 pipeline is two-way superscalar, but can only issue two +instructions together if the first one is 8-byte aligned. When this +option is enabled, GCC will align pairs of instructions that it +thinks should execute in parallel. + +This option only has an effect when optimizing for the VR4130. +It normally makes code faster, but at the expense of making it bigger. +It is enabled by default at optimization level @option{-O3}. +@end table + +@node MMIX Options +@subsection MMIX Options +@cindex MMIX Options + +These options are defined for the MMIX: + +@table @gcctabopt +@item -mlibfuncs +@itemx -mno-libfuncs +@opindex mlibfuncs +@opindex mno-libfuncs +Specify that intrinsic library functions are being compiled, passing all +values in registers, no matter the size. + +@item -mepsilon +@itemx -mno-epsilon +@opindex mepsilon +@opindex mno-epsilon +Generate floating-point comparison instructions that compare with respect +to the @code{rE} epsilon register. + +@item -mabi=mmixware +@itemx -mabi=gnu +@opindex mabi-mmixware +@opindex mabi=gnu +Generate code that passes function parameters and return values that (in +the called function) are seen as registers @code{$0} and up, as opposed to +the GNU ABI which uses global registers @code{$231} and up. + +@item -mzero-extend +@itemx -mno-zero-extend +@opindex mzero-extend +@opindex mno-zero-extend +When reading data from memory in sizes shorter than 64 bits, use (do not +use) zero-extending load instructions by default, rather than +sign-extending ones. + +@item -mknuthdiv +@itemx -mno-knuthdiv +@opindex mknuthdiv +@opindex mno-knuthdiv +Make the result of a division yielding a remainder have the same sign as +the divisor. With the default, @option{-mno-knuthdiv}, the sign of the +remainder follows the sign of the dividend. Both methods are +arithmetically valid, the latter being almost exclusively used. + +@item -mtoplevel-symbols +@itemx -mno-toplevel-symbols +@opindex mtoplevel-symbols +@opindex mno-toplevel-symbols +Prepend (do not prepend) a @samp{:} to all global symbols, so the assembly +code can be used with the @code{PREFIX} assembly directive. + +@item -melf +@opindex melf +Generate an executable in the ELF format, rather than the default +@samp{mmo} format used by the @command{mmix} simulator. + +@item -mbranch-predict +@itemx -mno-branch-predict +@opindex mbranch-predict +@opindex mno-branch-predict +Use (do not use) the probable-branch instructions, when static branch +prediction indicates a probable branch. + +@item -mbase-addresses +@itemx -mno-base-addresses +@opindex mbase-addresses +@opindex mno-base-addresses +Generate (do not generate) code that uses @emph{base addresses}. Using a +base address automatically generates a request (handled by the assembler +and the linker) for a constant to be set up in a global register. The +register is used for one or more base address requests within the range 0 +to 255 from the value held in the register. The generally leads to short +and fast code, but the number of different data items that can be +addressed is limited. This means that a program that uses lots of static +data may require @option{-mno-base-addresses}. + +@item -msingle-exit +@itemx -mno-single-exit +@opindex msingle-exit +@opindex mno-single-exit +Force (do not force) generated code to have a single exit point in each +function. +@end table + +@node MN10300 Options +@subsection MN10300 Options +@cindex MN10300 options + +These @option{-m} options are defined for Matsushita MN10300 architectures: + +@table @gcctabopt +@item -mmult-bug +@opindex mmult-bug +Generate code to avoid bugs in the multiply instructions for the MN10300 +processors. This is the default. + +@item -mno-mult-bug +@opindex mno-mult-bug +Do not generate code to avoid bugs in the multiply instructions for the +MN10300 processors. + +@item -mam33 +@opindex mam33 +Generate code which uses features specific to the AM33 processor. + +@item -mno-am33 +@opindex mno-am33 +Do not generate code which uses features specific to the AM33 processor. This +is the default. + +@item -mreturn-pointer-on-d0 +@opindex mreturn-pointer-on-d0 +When generating a function which returns a pointer, return the pointer +in both @code{a0} and @code{d0}. Otherwise, the pointer is returned +only in a0, and attempts to call such functions without a prototype +would result in errors. Note that this option is on by default; use +@option{-mno-return-pointer-on-d0} to disable it. + +@item -mno-crt0 +@opindex mno-crt0 +Do not link in the C run-time initialization object file. + +@item -mrelax +@opindex mrelax +Indicate to the linker that it should perform a relaxation optimization pass +to shorten branches, calls and absolute memory addresses. This option only +has an effect when used on the command line for the final link step. + +This option makes symbolic debugging impossible. +@end table + +@node MT Options +@subsection MT Options +@cindex MT options + +These @option{-m} options are defined for Morpho MT architectures: + +@table @gcctabopt + +@item -march=@var{cpu-type} +@opindex march +Generate code that will run on @var{cpu-type}, which is the name of a system +representing a certain processor type. Possible values for +@var{cpu-type} are @samp{ms1-64-001}, @samp{ms1-16-002}, +@samp{ms1-16-003} and @samp{ms2}. + +When this option is not used, the default is @option{-march=ms1-16-002}. + +@item -mbacc +@opindex mbacc +Use byte loads and stores when generating code. + +@item -mno-bacc +@opindex mno-bacc +Do not use byte loads and stores when generating code. + +@item -msim +@opindex msim +Use simulator runtime + +@item -mno-crt0 +@opindex mno-crt0 +Do not link in the C run-time initialization object file +@file{crti.o}. Other run-time initialization and termination files +such as @file{startup.o} and @file{exit.o} are still included on the +linker command line. + +@end table + +@node PDP-11 Options +@subsection PDP-11 Options +@cindex PDP-11 Options + +These options are defined for the PDP-11: + +@table @gcctabopt +@item -mfpu +@opindex mfpu +Use hardware FPP floating point. This is the default. (FIS floating +point on the PDP-11/40 is not supported.) + +@item -msoft-float +@opindex msoft-float +Do not use hardware floating point. + +@item -mac0 +@opindex mac0 +Return floating-point results in ac0 (fr0 in Unix assembler syntax). + +@item -mno-ac0 +@opindex mno-ac0 +Return floating-point results in memory. This is the default. + +@item -m40 +@opindex m40 +Generate code for a PDP-11/40. + +@item -m45 +@opindex m45 +Generate code for a PDP-11/45. This is the default. + +@item -m10 +@opindex m10 +Generate code for a PDP-11/10. + +@item -mbcopy-builtin +@opindex bcopy-builtin +Use inline @code{movmemhi} patterns for copying memory. This is the +default. + +@item -mbcopy +@opindex mbcopy +Do not use inline @code{movmemhi} patterns for copying memory. + +@item -mint16 +@itemx -mno-int32 +@opindex mint16 +@opindex mno-int32 +Use 16-bit @code{int}. This is the default. + +@item -mint32 +@itemx -mno-int16 +@opindex mint32 +@opindex mno-int16 +Use 32-bit @code{int}. + +@item -mfloat64 +@itemx -mno-float32 +@opindex mfloat64 +@opindex mno-float32 +Use 64-bit @code{float}. This is the default. + +@item -mfloat32 +@itemx -mno-float64 +@opindex mfloat32 +@opindex mno-float64 +Use 32-bit @code{float}. + +@item -mabshi +@opindex mabshi +Use @code{abshi2} pattern. This is the default. + +@item -mno-abshi +@opindex mno-abshi +Do not use @code{abshi2} pattern. + +@item -mbranch-expensive +@opindex mbranch-expensive +Pretend that branches are expensive. This is for experimenting with +code generation only. + +@item -mbranch-cheap +@opindex mbranch-cheap +Do not pretend that branches are expensive. This is the default. + +@item -msplit +@opindex msplit +Generate code for a system with split I&D@. + +@item -mno-split +@opindex mno-split +Generate code for a system without split I&D@. This is the default. + +@item -munix-asm +@opindex munix-asm +Use Unix assembler syntax. This is the default when configured for +@samp{pdp11-*-bsd}. + +@item -mdec-asm +@opindex mdec-asm +Use DEC assembler syntax. This is the default when configured for any +PDP-11 target other than @samp{pdp11-*-bsd}. +@end table +@c APPLE LOCAL prune man page +@end ignore + +@node PowerPC Options +@subsection PowerPC Options +@cindex PowerPC options + +These are listed under @xref{RS/6000 and PowerPC Options}. + +@node RS/6000 and PowerPC Options +@subsection IBM RS/6000 and PowerPC Options +@cindex RS/6000 and PowerPC Options +@cindex IBM RS/6000 and PowerPC Options + +These @samp{-m} options are defined for the IBM RS/6000 and PowerPC: +@table @gcctabopt +@item -mpower +@itemx -mno-power +@itemx -mpower2 +@itemx -mno-power2 +@itemx -mpowerpc +@itemx -mno-powerpc +@itemx -mpowerpc-gpopt +@itemx -mno-powerpc-gpopt +@itemx -mpowerpc-gfxopt +@itemx -mno-powerpc-gfxopt +@itemx -mpowerpc64 +@itemx -mno-powerpc64 +@itemx -mmfcrf +@itemx -mno-mfcrf +@itemx -mpopcntb +@itemx -mno-popcntb +@itemx -mfprnd +@itemx -mno-fprnd +@opindex mpower +@opindex mno-power +@opindex mpower2 +@opindex mno-power2 +@opindex mpowerpc +@opindex mno-powerpc +@opindex mpowerpc-gpopt +@opindex mno-powerpc-gpopt +@opindex mpowerpc-gfxopt +@opindex mno-powerpc-gfxopt +@opindex mpowerpc64 +@opindex mno-powerpc64 +@opindex mmfcrf +@opindex mno-mfcrf +@opindex mpopcntb +@opindex mno-popcntb +@opindex mfprnd +@opindex mno-fprnd +GCC supports two related instruction set architectures for the +RS/6000 and PowerPC@. The @dfn{POWER} instruction set are those +instructions supported by the @samp{rios} chip set used in the original +RS/6000 systems and the @dfn{PowerPC} instruction set is the +architecture of the Freescale MPC5xx, MPC6xx, MPC8xx microprocessors, and +the IBM 4xx, 6xx, and follow-on microprocessors. + +Neither architecture is a subset of the other. However there is a +large common subset of instructions supported by both. An MQ +register is included in processors supporting the POWER architecture. + +You use these options to specify which instructions are available on the +processor you are using. The default value of these options is +determined when configuring GCC@. Specifying the +@option{-mcpu=@var{cpu_type}} overrides the specification of these +options. We recommend you use the @option{-mcpu=@var{cpu_type}} option +rather than the options listed above. + +The @option{-mpower} option allows GCC to generate instructions that +are found only in the POWER architecture and to use the MQ register. +Specifying @option{-mpower2} implies @option{-power} and also allows GCC +to generate instructions that are present in the POWER2 architecture but +not the original POWER architecture. + +The @option{-mpowerpc} option allows GCC to generate instructions that +are found only in the 32-bit subset of the PowerPC architecture. +Specifying @option{-mpowerpc-gpopt} implies @option{-mpowerpc} and also allows +GCC to use the optional PowerPC architecture instructions in the +General Purpose group, including floating-point square root. Specifying +@option{-mpowerpc-gfxopt} implies @option{-mpowerpc} and also allows GCC to +use the optional PowerPC architecture instructions in the Graphics +group, including floating-point select. + +The @option{-mmfcrf} option allows GCC to generate the move from +condition register field instruction implemented on the POWER4 +processor and other processors that support the PowerPC V2.01 +architecture. +The @option{-mpopcntb} option allows GCC to generate the popcount and +double precision FP reciprocal estimate instruction implemented on the +POWER5 processor and other processors that support the PowerPC V2.02 +architecture. +The @option{-mfprnd} option allows GCC to generate the FP round to +integer instructions implemented on the POWER5+ processor and other +processors that support the PowerPC V2.03 architecture. + +The @option{-mpowerpc64} option allows GCC to generate the additional +64-bit instructions that are found in the full PowerPC64 architecture +and to treat GPRs as 64-bit, doubleword quantities. GCC defaults to +@option{-mno-powerpc64}. + +If you specify both @option{-mno-power} and @option{-mno-powerpc}, GCC +will use only the instructions in the common subset of both +architectures plus some special AIX common-mode calls, and will not use +the MQ register. Specifying both @option{-mpower} and @option{-mpowerpc} +permits GCC to use any instruction from either architecture and to +allow use of the MQ register; specify this for the Motorola MPC601. + +@item -mnew-mnemonics +@itemx -mold-mnemonics +@opindex mnew-mnemonics +@opindex mold-mnemonics +Select which mnemonics to use in the generated assembler code. With +@option{-mnew-mnemonics}, GCC uses the assembler mnemonics defined for +the PowerPC architecture. With @option{-mold-mnemonics} it uses the +assembler mnemonics defined for the POWER architecture. Instructions +defined in only one architecture have only one mnemonic; GCC uses that +mnemonic irrespective of which of these options is specified. + +GCC defaults to the mnemonics appropriate for the architecture in +use. Specifying @option{-mcpu=@var{cpu_type}} sometimes overrides the +value of these option. Unless you are building a cross-compiler, you +should normally not specify either @option{-mnew-mnemonics} or +@option{-mold-mnemonics}, but should instead accept the default. + +@item -mcpu=@var{cpu_type} +@opindex mcpu +Set architecture type, register usage, choice of mnemonics, and +instruction scheduling parameters for machine type @var{cpu_type}. +Supported values for @var{cpu_type} are @samp{401}, @samp{403}, +@samp{405}, @samp{405fp}, @samp{440}, @samp{440fp}, @samp{505}, +@samp{601}, @samp{602}, @samp{603}, @samp{603e}, @samp{604}, +@samp{604e}, @samp{620}, @samp{630}, @samp{740}, @samp{7400}, +@samp{7450}, @samp{750}, @samp{801}, @samp{821}, @samp{823}, +@samp{860}, @samp{970}, @samp{8540}, @samp{ec603e}, @samp{G3}, +@samp{G4}, @samp{G5}, @samp{power}, @samp{power2}, @samp{power3}, +@samp{power4}, @samp{power5}, @samp{power5+}, @samp{power6}, +@samp{common}, @samp{powerpc}, @samp{powerpc64}, +@samp{rios}, @samp{rios1}, @samp{rios2}, @samp{rsc}, and @samp{rs64}. + +@option{-mcpu=common} selects a completely generic processor. Code +generated under this option will run on any POWER or PowerPC processor. +GCC will use only the instructions in the common subset of both +architectures, and will not use the MQ register. GCC assumes a generic +processor model for scheduling purposes. + +@option{-mcpu=power}, @option{-mcpu=power2}, @option{-mcpu=powerpc}, and +@option{-mcpu=powerpc64} specify generic POWER, POWER2, pure 32-bit +PowerPC (i.e., not MPC601), and 64-bit PowerPC architecture machine +types, with an appropriate, generic processor model assumed for +scheduling purposes. + +The other options specify a specific processor. Code generated under +those options will run best on that processor, and may not run at all on +others. + +The @option{-mcpu} options automatically enable or disable the +following options: @option{-maltivec}, @option{-mfprnd}, +@option{-mhard-float}, @option{-mmfcrf}, @option{-mmultiple}, +@option{-mnew-mnemonics}, @option{-mpopcntb}, @option{-mpower}, +@option{-mpower2}, @option{-mpowerpc64}, @option{-mpowerpc-gpopt}, +@option{-mpowerpc-gfxopt}, @option{-mstring}, @option{-mmulhw}, @option{-mdlmzb}. +The particular options +set for any particular CPU will vary between compiler versions, +depending on what setting seems to produce optimal code for that CPU; +it doesn't necessarily reflect the actual hardware's capabilities. If +you wish to set an individual option to a particular value, you may +specify it after the @option{-mcpu} option, like @samp{-mcpu=970 +-mno-altivec}. + +On AIX, the @option{-maltivec} and @option{-mpowerpc64} options are +not enabled or disabled by the @option{-mcpu} option at present because +AIX does not have full support for these options. You may still +enable or disable them individually if you're sure it'll work in your +environment. + +@item -mtune=@var{cpu_type} +@opindex mtune +Set the instruction scheduling parameters for machine type +@var{cpu_type}, but do not set the architecture type, register usage, or +choice of mnemonics, as @option{-mcpu=@var{cpu_type}} would. The same +values for @var{cpu_type} are used for @option{-mtune} as for +@option{-mcpu}. If both are specified, the code generated will use the +architecture, registers, and mnemonics set by @option{-mcpu}, but the +scheduling parameters set by @option{-mtune}. + +@item -mswdiv +@itemx -mno-swdiv +@opindex mswdiv +@opindex mno-swdiv +Generate code to compute division as reciprocal estimate and iterative +refinement, creating opportunities for increased throughput. This +feature requires: optional PowerPC Graphics instruction set for single +precision and FRE instruction for double precision, assuming divides +cannot generate user-visible traps, and the domain values not include +Infinities, denormals or zero denominator. + +@item -maltivec +@itemx -mno-altivec +@opindex maltivec +@opindex mno-altivec +Generate code that uses (does not use) AltiVec instructions, and also +enable the use of built-in functions that allow more direct access to +the AltiVec instruction set. You may also need to set +@option{-mabi=altivec} to adjust the current ABI with AltiVec ABI +enhancements. + +@c APPLE LOCAL begin AltiVec +@item -mpim-altivec +@itemx -mno-pim-altivec +@opindex mpim-altivec +@opindex mno-pim-altivec +Enable (or disable) built-in compiler support for the syntactic extensions as +well as operations and predicates defined in the Motorola AltiVec +Technology Programming Interface Manual (PIM). This includes the +recognition of @code{vector} and @code{pixel} as (context-dependent) +keywords, the definition of built-in functions such as @code{vec_add}, +and the use of parenthesized comma expression as AltiVec literals. +Note that unlike the option @option{-maltivec}, the extension does not require +the inclusion of any special header files; if @code{<altivec.h>} is included, +a warning will be issued and the contents of the header will be +ignored. The preprocessor shall provide an @code{__APPLE_ALTIVEC__} +manifest constant when @option{-mpim-altivec} is specified. (APPLE ONLY) + +In addition, the @option{-mpim-altivec} option disables the inlining of +functions containing AltiVec instructions into functions that do not make +use of the vector unit. Certain other optimizations, such as inline +vectorization of @code{memset} and @code{memcpy} calls, are also disabled. +These adjustments make it possible to compile programs whose use of AltiVec +instructions is preceded by a run-time check for the presence of AltiVec +functionality, and that can therefore be made to run on G3 processors. +Note that all of these optimizations may be re-enabled by supplying +the @option{-maltivec} option, or an @option{-mcpu} option specifying +a processor that supports AltiVec instructions. +@c APPLE LOCAL end AltiVec + +@item -mvrsave +@item -mno-vrsave +@opindex mvrsave +@opindex mno-vrsave +Generate VRSAVE instructions when generating AltiVec code. + +@item -msecure-plt +@opindex msecure-plt +Generate code that allows ld and ld.so to build executables and shared +libraries with non-exec .plt and .got sections. This is a PowerPC +32-bit SYSV ABI option. + +@item -mbss-plt +@opindex mbss-plt +Generate code that uses a BSS .plt section that ld.so fills in, and +requires .plt and .got sections that are both writable and executable. +This is a PowerPC 32-bit SYSV ABI option. + +@item -misel +@itemx -mno-isel +@opindex misel +@opindex mno-isel +This switch enables or disables the generation of ISEL instructions. + +@item -misel=@var{yes/no} +This switch has been deprecated. Use @option{-misel} and +@option{-mno-isel} instead. + +@item -mspe +@itemx -mno-spe +@opindex mspe +@opindex mno-spe +This switch enables or disables the generation of SPE simd +instructions. + +@item -mspe=@var{yes/no} +This option has been deprecated. Use @option{-mspe} and +@option{-mno-spe} instead. + +@item -mfloat-gprs=@var{yes/single/double/no} +@itemx -mfloat-gprs +@opindex mfloat-gprs +This switch enables or disables the generation of floating point +operations on the general purpose registers for architectures that +support it. + +The argument @var{yes} or @var{single} enables the use of +single-precision floating point operations. + +The argument @var{double} enables the use of single and +double-precision floating point operations. + +The argument @var{no} disables floating point operations on the +general purpose registers. + +This option is currently only available on the MPC854x. + +@item -m32 +@itemx -m64 +@opindex m32 +@opindex m64 +Generate code for 32-bit or 64-bit environments of Darwin and SVR4 +targets (including GNU/Linux). The 32-bit environment sets int, long +and pointer to 32 bits and generates code that runs on any PowerPC +variant. The 64-bit environment sets int to 32 bits and long and +pointer to 64 bits, and generates code for PowerPC64, as for +@option{-mpowerpc64}. + +@item -mfull-toc +@itemx -mno-fp-in-toc +@itemx -mno-sum-in-toc +@itemx -mminimal-toc +@opindex mfull-toc +@opindex mno-fp-in-toc +@opindex mno-sum-in-toc +@opindex mminimal-toc +Modify generation of the TOC (Table Of Contents), which is created for +every executable file. The @option{-mfull-toc} option is selected by +default. In that case, GCC will allocate at least one TOC entry for +each unique non-automatic variable reference in your program. GCC +will also place floating-point constants in the TOC@. However, only +16,384 entries are available in the TOC@. + +If you receive a linker error message that saying you have overflowed +the available TOC space, you can reduce the amount of TOC space used +with the @option{-mno-fp-in-toc} and @option{-mno-sum-in-toc} options. +@option{-mno-fp-in-toc} prevents GCC from putting floating-point +constants in the TOC and @option{-mno-sum-in-toc} forces GCC to +generate code to calculate the sum of an address and a constant at +run-time instead of putting that sum into the TOC@. You may specify one +or both of these options. Each causes GCC to produce very slightly +slower and larger code at the expense of conserving TOC space. + +If you still run out of space in the TOC even when you specify both of +these options, specify @option{-mminimal-toc} instead. This option causes +GCC to make only one TOC entry for every file. When you specify this +option, GCC will produce code that is slower and larger but which +uses extremely little TOC space. You may wish to use this option +only on files that contain less frequently executed code. + +@item -maix64 +@itemx -maix32 +@opindex maix64 +@opindex maix32 +Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit +@code{long} type, and the infrastructure needed to support them. +Specifying @option{-maix64} implies @option{-mpowerpc64} and +@option{-mpowerpc}, while @option{-maix32} disables the 64-bit ABI and +implies @option{-mno-powerpc64}. GCC defaults to @option{-maix32}. + +@item -mxl-compat +@itemx -mno-xl-compat +@opindex mxl-compat +@opindex mno-xl-compat +Produce code that conforms more closely to IBM XL compiler semantics +when using AIX-compatible ABI. Pass floating-point arguments to +prototyped functions beyond the register save area (RSA) on the stack +in addition to argument FPRs. Do not assume that most significant +double in 128-bit long double value is properly rounded when comparing +values and converting to double. Use XL symbol names for long double +support routines. + +The AIX calling convention was extended but not initially documented to +handle an obscure K&R C case of calling a function that takes the +address of its arguments with fewer arguments than declared. IBM XL +compilers access floating point arguments which do not fit in the +RSA from the stack when a subroutine is compiled without +optimization. Because always storing floating-point arguments on the +stack is inefficient and rarely needed, this option is not enabled by +default and only is necessary when calling subroutines compiled by IBM +XL compilers without optimization. + +@item -mpe +@opindex mpe +Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE)@. Link an +application written to use message passing with special startup code to +enable the application to run. The system must have PE installed in the +standard location (@file{/usr/lpp/ppe.poe/}), or the @file{specs} file +must be overridden with the @option{-specs=} option to specify the +appropriate directory location. The Parallel Environment does not +support threads, so the @option{-mpe} option and the @option{-pthread} +option are incompatible. + +@item -malign-natural +@itemx -malign-power +@opindex malign-natural +@opindex malign-power +On AIX, 32-bit Darwin, and 64-bit PowerPC GNU/Linux, the option +@option{-malign-natural} overrides the ABI-defined alignment of larger +types, such as floating-point doubles, on their natural size-based boundary. +The option @option{-malign-power} instructs GCC to follow the ABI-specified +alignment rules. GCC defaults to the standard alignment defined in the ABI@. + +On 64-bit Darwin, natural alignment is the default, and @option{-malign-power} +is not supported. + +@item -msoft-float +@itemx -mhard-float +@opindex msoft-float +@opindex mhard-float +Generate code that does not use (uses) the floating-point register set. +Software floating point emulation is provided if you use the +@option{-msoft-float} option, and pass the option to GCC when linking. + +@c APPLE LOCAL begin describe actual behavior 3888787 +(APPLE ONLY) While the -msoft-float option is supported, the libraries that +do the floating point emulation are not shipped on Apple PowerPCs, with the +effect that the emulation does not work. However, the option +may be useful for a different reason. Normally the compiler can use floating +point registers in contexts where you might not expect it, for example, to +copy data from one memory location to another. The -msoft-float option will +prevent it from doing this. +@c APPLE LOCAL end describe actual behavior 3888787 + +@item -mmultiple +@itemx -mno-multiple +@opindex mmultiple +@opindex mno-multiple +Generate code that uses (does not use) the load multiple word +instructions and the store multiple word instructions. These +instructions are generated by default on POWER systems, and not +generated on PowerPC systems. Do not use @option{-mmultiple} on little +endian PowerPC systems, since those instructions do not work when the +processor is in little endian mode. The exceptions are PPC740 and +PPC750 which permit the instructions usage in little endian mode. + +@item -mstring +@itemx -mno-string +@opindex mstring +@opindex mno-string +Generate code that uses (does not use) the load string instructions +and the store string word instructions to save multiple registers and +do small block moves. These instructions are generated by default on +POWER systems, and not generated on PowerPC systems. Do not use +@option{-mstring} on little endian PowerPC systems, since those +instructions do not work when the processor is in little endian mode. +The exceptions are PPC740 and PPC750 which permit the instructions +usage in little endian mode. + +@item -mupdate +@itemx -mno-update +@opindex mupdate +@opindex mno-update +Generate code that uses (does not use) the load or store instructions +that update the base register to the address of the calculated memory +location. These instructions are generated by default. If you use +@option{-mno-update}, there is a small window between the time that the +stack pointer is updated and the address of the previous frame is +stored, which means code that walks the stack frame across interrupts or +signals may get corrupted data. + +@item -mfused-madd +@itemx -mno-fused-madd +@opindex mfused-madd +@opindex mno-fused-madd +Generate code that uses (does not use) the floating point multiply and +accumulate instructions. These instructions are generated by default if +hardware floating is used. + +@item -mmulhw +@itemx -mno-mulhw +@opindex mmulhw +@opindex mno-mulhw +Generate code that uses (does not use) the half-word multiply and +multiply-accumulate instructions on the IBM 405 and 440 processors. +These instructions are generated by default when targetting those +processors. + +@item -mdlmzb +@itemx -mno-dlmzb +@opindex mdlmzb +@opindex mno-dlmzb +Generate code that uses (does not use) the string-search @samp{dlmzb} +instruction on the IBM 405 and 440 processors. This instruction is +generated by default when targetting those processors. + +@item -mno-bit-align +@itemx -mbit-align +@opindex mno-bit-align +@opindex mbit-align +On System V.4 and embedded PowerPC systems do not (do) force structures +and unions that contain bit-fields to be aligned to the base type of the +bit-field. + +For example, by default a structure containing nothing but 8 +@code{unsigned} bit-fields of length 1 would be aligned to a 4 byte +boundary and have a size of 4 bytes. By using @option{-mno-bit-align}, +the structure would be aligned to a 1 byte boundary and be one byte in +size. + +@item -mno-strict-align +@itemx -mstrict-align +@opindex mno-strict-align +@opindex mstrict-align +On System V.4 and embedded PowerPC systems do not (do) assume that +unaligned memory references will be handled by the system. + +@item -mrelocatable +@itemx -mno-relocatable +@opindex mrelocatable +@opindex mno-relocatable +On embedded PowerPC systems generate code that allows (does not allow) +the program to be relocated to a different address at runtime. If you +use @option{-mrelocatable} on any module, all objects linked together must +be compiled with @option{-mrelocatable} or @option{-mrelocatable-lib}. + +@item -mrelocatable-lib +@itemx -mno-relocatable-lib +@opindex mrelocatable-lib +@opindex mno-relocatable-lib +On embedded PowerPC systems generate code that allows (does not allow) +the program to be relocated to a different address at runtime. Modules +compiled with @option{-mrelocatable-lib} can be linked with either modules +compiled without @option{-mrelocatable} and @option{-mrelocatable-lib} or +with modules compiled with the @option{-mrelocatable} options. + +@item -mno-toc +@itemx -mtoc +@opindex mno-toc +@opindex mtoc +On System V.4 and embedded PowerPC systems do not (do) assume that +register 2 contains a pointer to a global area pointing to the addresses +used in the program. + +@item -mlittle +@itemx -mlittle-endian +@opindex mlittle +@opindex mlittle-endian +On System V.4 and embedded PowerPC systems compile code for the +processor in little endian mode. The @option{-mlittle-endian} option is +the same as @option{-mlittle}. + +@item -mbig +@itemx -mbig-endian +@opindex mbig +@opindex mbig-endian +On System V.4 and embedded PowerPC systems compile code for the +processor in big endian mode. The @option{-mbig-endian} option is +the same as @option{-mbig}. + +@item -mdynamic-no-pic +@opindex mdynamic-no-pic +On Darwin and Mac OS X systems, compile code so that it is not +relocatable, but that its external references are relocatable. The +resulting code is suitable for applications, but not shared +libraries. + +@item -mprioritize-restricted-insns=@var{priority} +@opindex mprioritize-restricted-insns +This option controls the priority that is assigned to +dispatch-slot restricted instructions during the second scheduling +pass. The argument @var{priority} takes the value @var{0/1/2} to assign +@var{no/highest/second-highest} priority to dispatch slot restricted +instructions. + +@item -msched-costly-dep=@var{dependence_type} +@opindex msched-costly-dep +This option controls which dependences are considered costly +by the target during instruction scheduling. The argument +@var{dependence_type} takes one of the following values: +@var{no}: no dependence is costly, +@var{all}: all dependences are costly, +@var{true_store_to_load}: a true dependence from store to load is costly, +@var{store_to_load}: any dependence from store to load is costly, +@var{number}: any dependence which latency >= @var{number} is costly. + +@item -minsert-sched-nops=@var{scheme} +@opindex minsert-sched-nops +This option controls which nop insertion scheme will be used during +the second scheduling pass. The argument @var{scheme} takes one of the +following values: +@var{no}: Don't insert nops. +@var{pad}: Pad with nops any dispatch group which has vacant issue slots, +according to the scheduler's grouping. +@var{regroup_exact}: Insert nops to force costly dependent insns into +separate groups. Insert exactly as many nops as needed to force an insn +to a new group, according to the estimated processor grouping. +@var{number}: Insert nops to force costly dependent insns into +separate groups. Insert @var{number} nops to force an insn to a new group. + +@item -mcall-sysv +@opindex mcall-sysv +On System V.4 and embedded PowerPC systems compile code using calling +conventions that adheres to the March 1995 draft of the System V +Application Binary Interface, PowerPC processor supplement. This is the +default unless you configured GCC using @samp{powerpc-*-eabiaix}. + +@item -mcall-sysv-eabi +@opindex mcall-sysv-eabi +Specify both @option{-mcall-sysv} and @option{-meabi} options. + +@item -mcall-sysv-noeabi +@opindex mcall-sysv-noeabi +Specify both @option{-mcall-sysv} and @option{-mno-eabi} options. + +@item -mcall-solaris +@opindex mcall-solaris +On System V.4 and embedded PowerPC systems compile code for the Solaris +operating system. + +@item -mcall-linux +@opindex mcall-linux +On System V.4 and embedded PowerPC systems compile code for the +Linux-based GNU system. + +@item -mcall-gnu +@opindex mcall-gnu +On System V.4 and embedded PowerPC systems compile code for the +Hurd-based GNU system. + +@item -mcall-netbsd +@opindex mcall-netbsd +On System V.4 and embedded PowerPC systems compile code for the +NetBSD operating system. + +@item -maix-struct-return +@opindex maix-struct-return +Return all structures in memory (as specified by the AIX ABI)@. + +@item -msvr4-struct-return +@opindex msvr4-struct-return +Return structures smaller than 8 bytes in registers (as specified by the +SVR4 ABI)@. + +@item -mabi=@var{abi-type} +@opindex mabi +Extend the current ABI with a particular extension, or remove such extension. +Valid values are @var{altivec}, @var{no-altivec}, @var{spe}, +@var{no-spe}, @var{ibmlongdouble}, @var{ieeelongdouble}@. + +@item -mabi=spe +@opindex mabi=spe +Extend the current ABI with SPE ABI extensions. This does not change +the default ABI, instead it adds the SPE ABI extensions to the current +ABI@. + +@item -mabi=no-spe +@opindex mabi=no-spe +Disable Booke SPE ABI extensions for the current ABI@. + +@item -mabi=ibmlongdouble +@opindex mabi=ibmlongdouble +Change the current ABI to use IBM extended precision long double. +This is a PowerPC 32-bit SYSV ABI option. + +@item -mabi=ieeelongdouble +@opindex mabi=ieeelongdouble +Change the current ABI to use IEEE extended precision long double. +This is a PowerPC 32-bit Linux ABI option. + +@item -mprototype +@itemx -mno-prototype +@opindex mprototype +@opindex mno-prototype +On System V.4 and embedded PowerPC systems assume that all calls to +variable argument functions are properly prototyped. Otherwise, the +compiler must insert an instruction before every non prototyped call to +set or clear bit 6 of the condition code register (@var{CR}) to +indicate whether floating point values were passed in the floating point +registers in case the function takes a variable arguments. With +@option{-mprototype}, only calls to prototyped variable argument functions +will set or clear the bit. + +@item -msim +@opindex msim +On embedded PowerPC systems, assume that the startup module is called +@file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and +@file{libc.a}. This is the default for @samp{powerpc-*-eabisim}. +configurations. + +@item -mmvme +@opindex mmvme +On embedded PowerPC systems, assume that the startup module is called +@file{crt0.o} and the standard C libraries are @file{libmvme.a} and +@file{libc.a}. + +@item -mads +@opindex mads +On embedded PowerPC systems, assume that the startup module is called +@file{crt0.o} and the standard C libraries are @file{libads.a} and +@file{libc.a}. + +@item -myellowknife +@opindex myellowknife +On embedded PowerPC systems, assume that the startup module is called +@file{crt0.o} and the standard C libraries are @file{libyk.a} and +@file{libc.a}. + +@item -mvxworks +@opindex mvxworks +On System V.4 and embedded PowerPC systems, specify that you are +compiling for a VxWorks system. + +@item -mwindiss +@opindex mwindiss +Specify that you are compiling for the WindISS simulation environment. + +@item -memb +@opindex memb +On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags +header to indicate that @samp{eabi} extended relocations are used. + +@item -meabi +@itemx -mno-eabi +@opindex meabi +@opindex mno-eabi +On System V.4 and embedded PowerPC systems do (do not) adhere to the +Embedded Applications Binary Interface (eabi) which is a set of +modifications to the System V.4 specifications. Selecting @option{-meabi} +means that the stack is aligned to an 8 byte boundary, a function +@code{__eabi} is called to from @code{main} to set up the eabi +environment, and the @option{-msdata} option can use both @code{r2} and +@code{r13} to point to two separate small data areas. Selecting +@option{-mno-eabi} means that the stack is aligned to a 16 byte boundary, +do not call an initialization function from @code{main}, and the +@option{-msdata} option will only use @code{r13} to point to a single +small data area. The @option{-meabi} option is on by default if you +configured GCC using one of the @samp{powerpc*-*-eabi*} options. + +@item -msdata=eabi +@opindex msdata=eabi +On System V.4 and embedded PowerPC systems, put small initialized +@code{const} global and static data in the @samp{.sdata2} section, which +is pointed to by register @code{r2}. Put small initialized +non-@code{const} global and static data in the @samp{.sdata} section, +which is pointed to by register @code{r13}. Put small uninitialized +global and static data in the @samp{.sbss} section, which is adjacent to +the @samp{.sdata} section. The @option{-msdata=eabi} option is +incompatible with the @option{-mrelocatable} option. The +@option{-msdata=eabi} option also sets the @option{-memb} option. + +@item -msdata=sysv +@opindex msdata=sysv +On System V.4 and embedded PowerPC systems, put small global and static +data in the @samp{.sdata} section, which is pointed to by register +@code{r13}. Put small uninitialized global and static data in the +@samp{.sbss} section, which is adjacent to the @samp{.sdata} section. +The @option{-msdata=sysv} option is incompatible with the +@option{-mrelocatable} option. + +@item -msdata=default +@itemx -msdata +@opindex msdata=default +@opindex msdata +On System V.4 and embedded PowerPC systems, if @option{-meabi} is used, +compile code the same as @option{-msdata=eabi}, otherwise compile code the +same as @option{-msdata=sysv}. + +@item -msdata-data +@opindex msdata-data +On System V.4 and embedded PowerPC systems, put small global +data in the @samp{.sdata} section. Put small uninitialized global +data in the @samp{.sbss} section. Do not use register @code{r13} +to address small data however. This is the default behavior unless +other @option{-msdata} options are used. + +@item -msdata=none +@itemx -mno-sdata +@opindex msdata=none +@opindex mno-sdata +On embedded PowerPC systems, put all initialized global and static data +in the @samp{.data} section, and all uninitialized data in the +@samp{.bss} section. + +@item -G @var{num} +@opindex G +@cindex smaller data references (PowerPC) +@cindex .sdata/.sdata2 references (PowerPC) +On embedded PowerPC systems, put global and static items less than or +equal to @var{num} bytes into the small data or bss sections instead of +the normal data or bss section. By default, @var{num} is 8. The +@option{-G @var{num}} switch is also passed to the linker. +All modules should be compiled with the same @option{-G @var{num}} value. + +@item -mregnames +@itemx -mno-regnames +@opindex mregnames +@opindex mno-regnames +On System V.4 and embedded PowerPC systems do (do not) emit register +names in the assembly language output using symbolic forms. + +@item -mlongcall +@itemx -mno-longcall +@opindex mlongcall +@opindex mno-longcall +@c APPLE LOCAL begin 4222119 +@itemx -mlong-branch +@itemx -mno-long-branch +@opindex mlong-branch +@opindex mno-long-branch +@c APPLE LOCAL end 4222119 +By default assume that all calls are far away so that a longer more +expensive calling sequence is required. This is required for calls +further than 32 megabytes (33,554,432 bytes) from the current location. +A short call will be generated if the compiler knows +the call cannot be that far away. This setting can be overridden by +the @code{shortcall} function attribute, or by @code{#pragma +longcall(0)}. + +Some linkers are capable of detecting out-of-range calls and generating +glue code on the fly. On these systems, long calls are unnecessary and +generate slower code. As of this writing, the AIX linker can do this, +as can the GNU linker for PowerPC/64. It is planned to add this feature +to the GNU linker for 32-bit PowerPC systems as well. + +On Darwin/PPC systems, @code{#pragma longcall} will generate ``jbsr +callee, L42'', plus a ``branch island'' (glue code). The two target +addresses represent the callee and the ``branch island''. The +Darwin/PPC linker will prefer the first address and generate a ``bl +callee'' if the PPC ``bl'' instruction will reach the callee directly; +otherwise, the linker will generate ``bl L42'' to call the ``branch +island''. The ``branch island'' is appended to the body of the +calling function; it computes the full 32-bit address of the callee +and jumps to it. + +@c APPLE LOCAL begin 4222119 +On Mach-O (Darwin) systems, @option{-mlongcall} directs the compiler +emit to the glue for every direct call, and the Darwin linker decides +whether to use or discard it. @option{-mlong-branch} is a synonym for +@option{-mlongcall}. +@c APPLE LOCAL end 4222119 + +In the future, we may cause GCC to ignore all longcall specifications +when the linker is known to generate glue. + +@item -pthread +@opindex pthread +Adds support for multithreading with the @dfn{pthreads} library. +This option sets flags for both the preprocessor and linker. + +@c APPLE LOCAL begin 5946347 ms_struct support +@item -mms-bitfields +@opindex mms-bitfields +Set the default structure layout to be compatible with the Microsoft +compiler standard. This is equivalent to adding an @code{ms_struct} +attribute to each structure and union tag definition. The default is +@option{mno-ms-bitfields}. +@c APPLE LOCAL end 5946347 ms_struct support + +@end table + +@c APPLE LOCAL prune man page +@ignore +@node S/390 and zSeries Options +@subsection S/390 and zSeries Options +@cindex S/390 and zSeries Options + +These are the @samp{-m} options defined for the S/390 and zSeries architecture. + +@table @gcctabopt +@item -mhard-float +@itemx -msoft-float +@opindex mhard-float +@opindex msoft-float +Use (do not use) the hardware floating-point instructions and registers +for floating-point operations. When @option{-msoft-float} is specified, +functions in @file{libgcc.a} will be used to perform floating-point +operations. When @option{-mhard-float} is specified, the compiler +generates IEEE floating-point instructions. This is the default. + +@item -mlong-double-64 +@itemx -mlong-double-128 +@opindex mlong-double-64 +@opindex mlong-double-128 +These switches control the size of @code{long double} type. A size +of 64bit makes the @code{long double} type equivalent to the @code{double} +type. This is the default. + +@item -mbackchain +@itemx -mno-backchain +@opindex mbackchain +@opindex mno-backchain +Store (do not store) the address of the caller's frame as backchain pointer +into the callee's stack frame. +A backchain may be needed to allow debugging using tools that do not understand +DWARF-2 call frame information. +When @option{-mno-packed-stack} is in effect, the backchain pointer is stored +at the bottom of the stack frame; when @option{-mpacked-stack} is in effect, +the backchain is placed into the topmost word of the 96/160 byte register +save area. + +In general, code compiled with @option{-mbackchain} is call-compatible with +code compiled with @option{-mmo-backchain}; however, use of the backchain +for debugging purposes usually requires that the whole binary is built with +@option{-mbackchain}. Note that the combination of @option{-mbackchain}, +@option{-mpacked-stack} and @option{-mhard-float} is not supported. In order +to build a linux kernel use @option{-msoft-float}. + +The default is to not maintain the backchain. + +@item -mpacked-stack +@item -mno-packed-stack +@opindex mpacked-stack +@opindex mno-packed-stack +Use (do not use) the packed stack layout. When @option{-mno-packed-stack} is +specified, the compiler uses the all fields of the 96/160 byte register save +area only for their default purpose; unused fields still take up stack space. +When @option{-mpacked-stack} is specified, register save slots are densely +packed at the top of the register save area; unused space is reused for other +purposes, allowing for more efficient use of the available stack space. +However, when @option{-mbackchain} is also in effect, the topmost word of +the save area is always used to store the backchain, and the return address +register is always saved two words below the backchain. + +As long as the stack frame backchain is not used, code generated with +@option{-mpacked-stack} is call-compatible with code generated with +@option{-mno-packed-stack}. Note that some non-FSF releases of GCC 2.95 for +S/390 or zSeries generated code that uses the stack frame backchain at run +time, not just for debugging purposes. Such code is not call-compatible +with code compiled with @option{-mpacked-stack}. Also, note that the +combination of @option{-mbackchain}, +@option{-mpacked-stack} and @option{-mhard-float} is not supported. In order +to build a linux kernel use @option{-msoft-float}. + +The default is to not use the packed stack layout. + +@item -msmall-exec +@itemx -mno-small-exec +@opindex msmall-exec +@opindex mno-small-exec +Generate (or do not generate) code using the @code{bras} instruction +to do subroutine calls. +This only works reliably if the total executable size does not +exceed 64k. The default is to use the @code{basr} instruction instead, +which does not have this limitation. + +@item -m64 +@itemx -m31 +@opindex m64 +@opindex m31 +When @option{-m31} is specified, generate code compliant to the +GNU/Linux for S/390 ABI@. When @option{-m64} is specified, generate +code compliant to the GNU/Linux for zSeries ABI@. This allows GCC in +particular to generate 64-bit instructions. For the @samp{s390} +targets, the default is @option{-m31}, while the @samp{s390x} +targets default to @option{-m64}. + +@item -mzarch +@itemx -mesa +@opindex mzarch +@opindex mesa +When @option{-mzarch} is specified, generate code using the +instructions available on z/Architecture. +When @option{-mesa} is specified, generate code using the +instructions available on ESA/390. Note that @option{-mesa} is +not possible with @option{-m64}. +When generating code compliant to the GNU/Linux for S/390 ABI, +the default is @option{-mesa}. When generating code compliant +to the GNU/Linux for zSeries ABI, the default is @option{-mzarch}. + +@item -mmvcle +@itemx -mno-mvcle +@opindex mmvcle +@opindex mno-mvcle +Generate (or do not generate) code using the @code{mvcle} instruction +to perform block moves. When @option{-mno-mvcle} is specified, +use a @code{mvc} loop instead. This is the default unless optimizing for +size. + +@item -mdebug +@itemx -mno-debug +@opindex mdebug +@opindex mno-debug +Print (or do not print) additional debug information when compiling. +The default is to not print debug information. + +@item -march=@var{cpu-type} +@opindex march +Generate code that will run on @var{cpu-type}, which is the name of a system +representing a certain processor type. Possible values for +@var{cpu-type} are @samp{g5}, @samp{g6}, @samp{z900}, and @samp{z990}. +When generating code using the instructions available on z/Architecture, +the default is @option{-march=z900}. Otherwise, the default is +@option{-march=g5}. + +@item -mtune=@var{cpu-type} +@opindex mtune +Tune to @var{cpu-type} everything applicable about the generated code, +except for the ABI and the set of available instructions. +The list of @var{cpu-type} values is the same as for @option{-march}. +The default is the value used for @option{-march}. + +@item -mtpf-trace +@itemx -mno-tpf-trace +@opindex mtpf-trace +@opindex mno-tpf-trace +Generate code that adds (does not add) in TPF OS specific branches to trace +routines in the operating system. This option is off by default, even +when compiling for the TPF OS@. + +@item -mfused-madd +@itemx -mno-fused-madd +@opindex mfused-madd +@opindex mno-fused-madd +Generate code that uses (does not use) the floating point multiply and +accumulate instructions. These instructions are generated by default if +hardware floating point is used. + +@item -mwarn-framesize=@var{framesize} +@opindex mwarn-framesize +Emit a warning if the current function exceeds the given frame size. Because +this is a compile time check it doesn't need to be a real problem when the program +runs. It is intended to identify functions which most probably cause +a stack overflow. It is useful to be used in an environment with limited stack +size e.g.@: the linux kernel. + +@item -mwarn-dynamicstack +@opindex mwarn-dynamicstack +Emit a warning if the function calls alloca or uses dynamically +sized arrays. This is generally a bad idea with a limited stack size. + +@item -mstack-guard=@var{stack-guard} +@item -mstack-size=@var{stack-size} +@opindex mstack-guard +@opindex mstack-size +These arguments always have to be used in conjunction. If they are present the s390 +back end emits additional instructions in the function prologue which trigger a trap +if the stack size is @var{stack-guard} bytes above the @var{stack-size} +(remember that the stack on s390 grows downward). These options are intended to +be used to help debugging stack overflow problems. The additionally emitted code +causes only little overhead and hence can also be used in production like systems +without greater performance degradation. The given values have to be exact +powers of 2 and @var{stack-size} has to be greater than @var{stack-guard} without +exceeding 64k. +In order to be efficient the extra code makes the assumption that the stack starts +at an address aligned to the value given by @var{stack-size}. +@end table + +@node Score Options +@subsection Score Options +@cindex Score Options + +These options are defined for Score implementations: + +@table @gcctabopt +@item -meb +@opindex meb +Compile code for big endian mode. This is the default. + +@item -mel +@opindex mel +Compile code for little endian mode. + +@item -mnhwloop +@opindex mnhwloop +Disable generate bcnz instruction. + +@item -muls +@opindex muls +Enable generate unaligned load and store instruction. + +@item -mmac +@opindex mmac +Enable the use of multiply-accumulate instructions. Disabled by default. + +@item -mscore5 +@opindex mscore5 +Specify the SCORE5 as the target architecture. + +@item -mscore5u +@opindex mscore5u +Specify the SCORE5U of the target architecture. + +@item -mscore7 +@opindex mscore7 +Specify the SCORE7 as the target architecture. This is the default. + +@item -mscore7d +@opindex mscore7d +Specify the SCORE7D as the target architecture. +@end table + +@node SH Options +@subsection SH Options + +These @samp{-m} options are defined for the SH implementations: + +@table @gcctabopt +@item -m1 +@opindex m1 +Generate code for the SH1. + +@item -m2 +@opindex m2 +Generate code for the SH2. + +@item -m2e +Generate code for the SH2e. + +@item -m3 +@opindex m3 +Generate code for the SH3. + +@item -m3e +@opindex m3e +Generate code for the SH3e. + +@item -m4-nofpu +@opindex m4-nofpu +Generate code for the SH4 without a floating-point unit. + +@item -m4-single-only +@opindex m4-single-only +Generate code for the SH4 with a floating-point unit that only +supports single-precision arithmetic. + +@item -m4-single +@opindex m4-single +Generate code for the SH4 assuming the floating-point unit is in +single-precision mode by default. + +@item -m4 +@opindex m4 +Generate code for the SH4. + +@item -m4a-nofpu +@opindex m4a-nofpu +Generate code for the SH4al-dsp, or for a SH4a in such a way that the +floating-point unit is not used. + +@item -m4a-single-only +@opindex m4a-single-only +Generate code for the SH4a, in such a way that no double-precision +floating point operations are used. + +@item -m4a-single +@opindex m4a-single +Generate code for the SH4a assuming the floating-point unit is in +single-precision mode by default. + +@item -m4a +@opindex m4a +Generate code for the SH4a. + +@item -m4al +@opindex m4al +Same as @option{-m4a-nofpu}, except that it implicitly passes +@option{-dsp} to the assembler. GCC doesn't generate any DSP +instructions at the moment. + +@item -mb +@opindex mb +Compile code for the processor in big endian mode. + +@item -ml +@opindex ml +Compile code for the processor in little endian mode. + +@item -mdalign +@opindex mdalign +Align doubles at 64-bit boundaries. Note that this changes the calling +conventions, and thus some functions from the standard C library will +not work unless you recompile it first with @option{-mdalign}. + +@item -mrelax +@opindex mrelax +Shorten some address references at link time, when possible; uses the +linker option @option{-relax}. + +@item -mbigtable +@opindex mbigtable +Use 32-bit offsets in @code{switch} tables. The default is to use +16-bit offsets. + +@item -mfmovd +@opindex mfmovd +Enable the use of the instruction @code{fmovd}. + +@item -mhitachi +@opindex mhitachi +Comply with the calling conventions defined by Renesas. + +@item -mrenesas +@opindex mhitachi +Comply with the calling conventions defined by Renesas. + +@item -mno-renesas +@opindex mhitachi +Comply with the calling conventions defined for GCC before the Renesas +conventions were available. This option is the default for all +targets of the SH toolchain except for @samp{sh-symbianelf}. + +@item -mnomacsave +@opindex mnomacsave +Mark the @code{MAC} register as call-clobbered, even if +@option{-mhitachi} is given. + +@item -mieee +@opindex mieee +Increase IEEE-compliance of floating-point code. +At the moment, this is equivalent to @option{-fno-finite-math-only}. +When generating 16 bit SH opcodes, getting IEEE-conforming results for +comparisons of NANs / infinities incurs extra overhead in every +floating point comparison, therefore the default is set to +@option{-ffinite-math-only}. + +@item -misize +@opindex misize +Dump instruction size and location in the assembly code. + +@item -mpadstruct +@opindex mpadstruct +This option is deprecated. It pads structures to multiple of 4 bytes, +which is incompatible with the SH ABI@. + +@item -mspace +@opindex mspace +@c APPLE LOCAL 4231761 -Oz +Optimize for space instead of speed. Implied by @option{-Os} and @option{-Oz} (APPLE ONLY). + +@item -mprefergot +@opindex mprefergot +When generating position-independent code, emit function calls using +the Global Offset Table instead of the Procedure Linkage Table. + +@item -musermode +@opindex musermode +Generate a library function call to invalidate instruction cache +entries, after fixing up a trampoline. This library function call +doesn't assume it can write to the whole memory address space. This +is the default when the target is @code{sh-*-linux*}. + +@item -multcost=@var{number} +@opindex multcost=@var{number} +Set the cost to assume for a multiply insn. + +@item -mdiv=@var{strategy} +@opindex mdiv=@var{strategy} +Set the division strategy to use for SHmedia code. @var{strategy} must be +one of: call, call2, fp, inv, inv:minlat, inv20u, inv20l, inv:call, +inv:call2, inv:fp . +"fp" performs the operation in floating point. This has a very high latency, +but needs only a few instructions, so it might be a good choice if +your code has enough easily exploitable ILP to allow the compiler to +schedule the floating point instructions together with other instructions. +Division by zero causes a floating point exception. +"inv" uses integer operations to calculate the inverse of the divisor, +and then multiplies the dividend with the inverse. This strategy allows +cse and hoisting of the inverse calculation. Division by zero calculates +an unspecified result, but does not trap. +"inv:minlat" is a variant of "inv" where if no cse / hoisting opportunities +have been found, or if the entire operation has been hoisted to the same +place, the last stages of the inverse calculation are intertwined with the +final multiply to reduce the overall latency, at the expense of using a few +more instructions, and thus offering fewer scheduling opportunities with +other code. +"call" calls a library function that usually implements the inv:minlat +strategy. +This gives high code density for m5-*media-nofpu compilations. +"call2" uses a different entry point of the same library function, where it +assumes that a pointer to a lookup table has already been set up, which +exposes the pointer load to cse / code hoisting optimizations. +"inv:call", "inv:call2" and "inv:fp" all use the "inv" algorithm for initial +code generation, but if the code stays unoptimized, revert to the "call", +"call2", or "fp" strategies, respectively. Note that the +potentially-trapping side effect of division by zero is carried by a +separate instruction, so it is possible that all the integer instructions +are hoisted out, but the marker for the side effect stays where it is. +A recombination to fp operations or a call is not possible in that case. +"inv20u" and "inv20l" are variants of the "inv:minlat" strategy. In the case +that the inverse calculation was nor separated from the multiply, they speed +up division where the dividend fits into 20 bits (plus sign where applicable), +by inserting a test to skip a number of operations in this case; this test +slows down the case of larger dividends. inv20u assumes the case of a such +a small dividend to be unlikely, and inv20l assumes it to be likely. + +@item -mdivsi3_libfunc=@var{name} +@opindex mdivsi3_libfunc=@var{name} +Set the name of the library function used for 32 bit signed division to +@var{name}. This only affect the name used in the call and inv:call +division strategies, and the compiler will still expect the same +sets of input/output/clobbered registers as if this option was not present. + +@item -madjust-unroll +@opindex madjust-unroll +Throttle unrolling to avoid thrashing target registers. +This option only has an effect if the gcc code base supports the +TARGET_ADJUST_UNROLL_MAX target hook. + +@item -mindexed-addressing +@opindex mindexed-addressing +Enable the use of the indexed addressing mode for SHmedia32/SHcompact. +This is only safe if the hardware and/or OS implement 32 bit wrap-around +semantics for the indexed addressing mode. The architecture allows the +implementation of processors with 64 bit MMU, which the OS could use to +get 32 bit addressing, but since no current hardware implementation supports +this or any other way to make the indexed addressing mode safe to use in +the 32 bit ABI, the default is -mno-indexed-addressing. + +@item -mgettrcost=@var{number} +@opindex mgettrcost=@var{number} +Set the cost assumed for the gettr instruction to @var{number}. +The default is 2 if @option{-mpt-fixed} is in effect, 100 otherwise. + +@item -mpt-fixed +@opindex mpt-fixed +Assume pt* instructions won't trap. This will generally generate better +scheduled code, but is unsafe on current hardware. The current architecture +definition says that ptabs and ptrel trap when the target anded with 3 is 3. +This has the unintentional effect of making it unsafe to schedule ptabs / +ptrel before a branch, or hoist it out of a loop. For example, +__do_global_ctors, a part of libgcc that runs constructors at program +startup, calls functions in a list which is delimited by -1. With the +-mpt-fixed option, the ptabs will be done before testing against -1. +That means that all the constructors will be run a bit quicker, but when +the loop comes to the end of the list, the program crashes because ptabs +loads -1 into a target register. Since this option is unsafe for any +hardware implementing the current architecture specification, the default +is -mno-pt-fixed. Unless the user specifies a specific cost with +@option{-mgettrcost}, -mno-pt-fixed also implies @option{-mgettrcost=100}; +this deters register allocation using target registers for storing +ordinary integers. + +@item -minvalid-symbols +@opindex minvalid-symbols +Assume symbols might be invalid. Ordinary function symbols generated by +the compiler will always be valid to load with movi/shori/ptabs or +movi/shori/ptrel, but with assembler and/or linker tricks it is possible +to generate symbols that will cause ptabs / ptrel to trap. +This option is only meaningful when @option{-mno-pt-fixed} is in effect. +It will then prevent cross-basic-block cse, hoisting and most scheduling +of symbol loads. The default is @option{-mno-invalid-symbols}. +@end table + +@node SPARC Options +@subsection SPARC Options +@cindex SPARC options + +These @samp{-m} options are supported on the SPARC: + +@table @gcctabopt +@item -mno-app-regs +@itemx -mapp-regs +@opindex mno-app-regs +@opindex mapp-regs +Specify @option{-mapp-regs} to generate output using the global registers +2 through 4, which the SPARC SVR4 ABI reserves for applications. This +is the default. + +To be fully SVR4 ABI compliant at the cost of some performance loss, +specify @option{-mno-app-regs}. You should compile libraries and system +software with this option. + +@item -mfpu +@itemx -mhard-float +@opindex mfpu +@opindex mhard-float +Generate output containing floating point instructions. This is the +default. + +@item -mno-fpu +@itemx -msoft-float +@opindex mno-fpu +@opindex msoft-float +Generate output containing library calls for floating point. +@strong{Warning:} the requisite libraries are not available for all SPARC +targets. Normally the facilities of the machine's usual C compiler are +used, but this cannot be done directly in cross-compilation. You must make +your own arrangements to provide suitable library functions for +cross-compilation. The embedded targets @samp{sparc-*-aout} and +@samp{sparclite-*-*} do provide software floating point support. + +@option{-msoft-float} changes the calling convention in the output file; +therefore, it is only useful if you compile @emph{all} of a program with +this option. In particular, you need to compile @file{libgcc.a}, the +library that comes with GCC, with @option{-msoft-float} in order for +this to work. + +@item -mhard-quad-float +@opindex mhard-quad-float +Generate output containing quad-word (long double) floating point +instructions. + +@item -msoft-quad-float +@opindex msoft-quad-float +Generate output containing library calls for quad-word (long double) +floating point instructions. The functions called are those specified +in the SPARC ABI@. This is the default. + +As of this writing, there are no SPARC implementations that have hardware +support for the quad-word floating point instructions. They all invoke +a trap handler for one of these instructions, and then the trap handler +emulates the effect of the instruction. Because of the trap handler overhead, +this is much slower than calling the ABI library routines. Thus the +@option{-msoft-quad-float} option is the default. + +@item -mno-unaligned-doubles +@itemx -munaligned-doubles +@opindex mno-unaligned-doubles +@opindex munaligned-doubles +Assume that doubles have 8 byte alignment. This is the default. + +With @option{-munaligned-doubles}, GCC assumes that doubles have 8 byte +alignment only if they are contained in another type, or if they have an +absolute address. Otherwise, it assumes they have 4 byte alignment. +Specifying this option avoids some rare compatibility problems with code +generated by other compilers. It is not the default because it results +in a performance loss, especially for floating point code. + +@item -mno-faster-structs +@itemx -mfaster-structs +@opindex mno-faster-structs +@opindex mfaster-structs +With @option{-mfaster-structs}, the compiler assumes that structures +should have 8 byte alignment. This enables the use of pairs of +@code{ldd} and @code{std} instructions for copies in structure +assignment, in place of twice as many @code{ld} and @code{st} pairs. +However, the use of this changed alignment directly violates the SPARC +ABI@. Thus, it's intended only for use on targets where the developer +acknowledges that their resulting code will not be directly in line with +the rules of the ABI@. + +@item -mimpure-text +@opindex mimpure-text +@option{-mimpure-text}, used in addition to @option{-shared}, tells +the compiler to not pass @option{-z text} to the linker when linking a +shared object. Using this option, you can link position-dependent +code into a shared object. + +@option{-mimpure-text} suppresses the ``relocations remain against +allocatable but non-writable sections'' linker error message. +However, the necessary relocations will trigger copy-on-write, and the +shared object is not actually shared across processes. Instead of +using @option{-mimpure-text}, you should compile all source code with +@option{-fpic} or @option{-fPIC}. + +This option is only available on SunOS and Solaris. + +@item -mcpu=@var{cpu_type} +@opindex mcpu +Set the instruction set, register set, and instruction scheduling parameters +for machine type @var{cpu_type}. Supported values for @var{cpu_type} are +@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite}, +@samp{f930}, @samp{f934}, @samp{hypersparc}, @samp{sparclite86x}, +@samp{sparclet}, @samp{tsc701}, @samp{v9}, @samp{ultrasparc}, +@samp{ultrasparc3}, and @samp{niagara}. + +Default instruction scheduling parameters are used for values that select +an architecture and not an implementation. These are @samp{v7}, @samp{v8}, +@samp{sparclite}, @samp{sparclet}, @samp{v9}. + +Here is a list of each supported architecture and their supported +implementations. + +@smallexample + v7: cypress + v8: supersparc, hypersparc + sparclite: f930, f934, sparclite86x + sparclet: tsc701 + v9: ultrasparc, ultrasparc3, niagara +@end smallexample + +By default (unless configured otherwise), GCC generates code for the V7 +variant of the SPARC architecture. With @option{-mcpu=cypress}, the compiler +additionally optimizes it for the Cypress CY7C602 chip, as used in the +SPARCStation/SPARCServer 3xx series. This is also appropriate for the older +SPARCStation 1, 2, IPX etc. + +With @option{-mcpu=v8}, GCC generates code for the V8 variant of the SPARC +architecture. The only difference from V7 code is that the compiler emits +the integer multiply and integer divide instructions which exist in SPARC-V8 +but not in SPARC-V7. With @option{-mcpu=supersparc}, the compiler additionally +optimizes it for the SuperSPARC chip, as used in the SPARCStation 10, 1000 and +2000 series. + +With @option{-mcpu=sparclite}, GCC generates code for the SPARClite variant of +the SPARC architecture. This adds the integer multiply, integer divide step +and scan (@code{ffs}) instructions which exist in SPARClite but not in SPARC-V7. +With @option{-mcpu=f930}, the compiler additionally optimizes it for the +Fujitsu MB86930 chip, which is the original SPARClite, with no FPU@. With +@option{-mcpu=f934}, the compiler additionally optimizes it for the Fujitsu +MB86934 chip, which is the more recent SPARClite with FPU@. + +With @option{-mcpu=sparclet}, GCC generates code for the SPARClet variant of +the SPARC architecture. This adds the integer multiply, multiply/accumulate, +integer divide step and scan (@code{ffs}) instructions which exist in SPARClet +but not in SPARC-V7. With @option{-mcpu=tsc701}, the compiler additionally +optimizes it for the TEMIC SPARClet chip. + +With @option{-mcpu=v9}, GCC generates code for the V9 variant of the SPARC +architecture. This adds 64-bit integer and floating-point move instructions, +3 additional floating-point condition code registers and conditional move +instructions. With @option{-mcpu=ultrasparc}, the compiler additionally +optimizes it for the Sun UltraSPARC I/II/IIi chips. With +@option{-mcpu=ultrasparc3}, the compiler additionally optimizes it for the +Sun UltraSPARC III/III+/IIIi/IIIi+/IV/IV+ chips. With +@option{-mcpu=niagara}, the compiler additionally optimizes it for +Sun UltraSPARC T1 chips. + +@item -mtune=@var{cpu_type} +@opindex mtune +Set the instruction scheduling parameters for machine type +@var{cpu_type}, but do not set the instruction set or register set that the +option @option{-mcpu=@var{cpu_type}} would. + +The same values for @option{-mcpu=@var{cpu_type}} can be used for +@option{-mtune=@var{cpu_type}}, but the only useful values are those +that select a particular cpu implementation. Those are @samp{cypress}, +@samp{supersparc}, @samp{hypersparc}, @samp{f930}, @samp{f934}, +@samp{sparclite86x}, @samp{tsc701}, @samp{ultrasparc}, +@samp{ultrasparc3}, and @samp{niagara}. + +@item -mv8plus +@itemx -mno-v8plus +@opindex mv8plus +@opindex mno-v8plus +With @option{-mv8plus}, GCC generates code for the SPARC-V8+ ABI@. The +difference from the V8 ABI is that the global and out registers are +considered 64-bit wide. This is enabled by default on Solaris in 32-bit +mode for all SPARC-V9 processors. + +@item -mvis +@itemx -mno-vis +@opindex mvis +@opindex mno-vis +With @option{-mvis}, GCC generates code that takes advantage of the UltraSPARC +Visual Instruction Set extensions. The default is @option{-mno-vis}. +@end table + +These @samp{-m} options are supported in addition to the above +on SPARC-V9 processors in 64-bit environments: + +@table @gcctabopt +@item -mlittle-endian +@opindex mlittle-endian +Generate code for a processor running in little-endian mode. It is only +available for a few configurations and most notably not on Solaris and Linux. + +@item -m32 +@itemx -m64 +@opindex m32 +@opindex m64 +Generate code for a 32-bit or 64-bit environment. +The 32-bit environment sets int, long and pointer to 32 bits. +The 64-bit environment sets int to 32 bits and long and pointer +to 64 bits. + +@item -mcmodel=medlow +@opindex mcmodel=medlow +Generate code for the Medium/Low code model: 64-bit addresses, programs +must be linked in the low 32 bits of memory. Programs can be statically +or dynamically linked. + +@item -mcmodel=medmid +@opindex mcmodel=medmid +Generate code for the Medium/Middle code model: 64-bit addresses, programs +must be linked in the low 44 bits of memory, the text and data segments must +be less than 2GB in size and the data segment must be located within 2GB of +the text segment. + +@item -mcmodel=medany +@opindex mcmodel=medany +Generate code for the Medium/Anywhere code model: 64-bit addresses, programs +may be linked anywhere in memory, the text and data segments must be less +than 2GB in size and the data segment must be located within 2GB of the +text segment. + +@item -mcmodel=embmedany +@opindex mcmodel=embmedany +Generate code for the Medium/Anywhere code model for embedded systems: +64-bit addresses, the text and data segments must be less than 2GB in +size, both starting anywhere in memory (determined at link time). The +global register %g4 points to the base of the data segment. Programs +are statically linked and PIC is not supported. + +@item -mstack-bias +@itemx -mno-stack-bias +@opindex mstack-bias +@opindex mno-stack-bias +With @option{-mstack-bias}, GCC assumes that the stack pointer, and +frame pointer if present, are offset by @minus{}2047 which must be added back +when making stack frame references. This is the default in 64-bit mode. +Otherwise, assume no such offset is present. +@end table + +These switches are supported in addition to the above on Solaris: + +@table @gcctabopt +@item -threads +@opindex threads +Add support for multithreading using the Solaris threads library. This +option sets flags for both the preprocessor and linker. This option does +not affect the thread safety of object code produced by the compiler or +that of libraries supplied with it. + +@item -pthreads +@opindex pthreads +Add support for multithreading using the POSIX threads library. This +option sets flags for both the preprocessor and linker. This option does +not affect the thread safety of object code produced by the compiler or +that of libraries supplied with it. + +@item -pthread +@opindex pthread +This is a synonym for @option{-pthreads}. +@end table + +@node System V Options +@subsection Options for System V + +These additional options are available on System V Release 4 for +compatibility with other compilers on those systems: + +@table @gcctabopt +@item -G +@opindex G +Create a shared object. +It is recommended that @option{-symbolic} or @option{-shared} be used instead. + +@item -Qy +@opindex Qy +Identify the versions of each tool used by the compiler, in a +@code{.ident} assembler directive in the output. + +@item -Qn +@opindex Qn +Refrain from adding @code{.ident} directives to the output file (this is +the default). + +@item -YP,@var{dirs} +@opindex YP +Search the directories @var{dirs}, and no others, for libraries +specified with @option{-l}. + +@item -Ym,@var{dir} +@opindex Ym +Look in the directory @var{dir} to find the M4 preprocessor. +The assembler uses this option. +@c This is supposed to go with a -Yd for predefined M4 macro files, but +@c the generic assembler that comes with Solaris takes just -Ym. +@end table + +@node TMS320C3x/C4x Options +@subsection TMS320C3x/C4x Options +@cindex TMS320C3x/C4x Options + +These @samp{-m} options are defined for TMS320C3x/C4x implementations: + +@table @gcctabopt + +@item -mcpu=@var{cpu_type} +@opindex mcpu +Set the instruction set, register set, and instruction scheduling +parameters for machine type @var{cpu_type}. Supported values for +@var{cpu_type} are @samp{c30}, @samp{c31}, @samp{c32}, @samp{c40}, and +@samp{c44}. The default is @samp{c40} to generate code for the +TMS320C40. + +@item -mbig-memory +@itemx -mbig +@itemx -msmall-memory +@itemx -msmall +@opindex mbig-memory +@opindex mbig +@opindex msmall-memory +@opindex msmall +Generates code for the big or small memory model. The small memory +model assumed that all data fits into one 64K word page. At run-time +the data page (DP) register must be set to point to the 64K page +containing the .bss and .data program sections. The big memory model is +the default and requires reloading of the DP register for every direct +memory access. + +@item -mbk +@itemx -mno-bk +@opindex mbk +@opindex mno-bk +Allow (disallow) allocation of general integer operands into the block +count register BK@. + +@item -mdb +@itemx -mno-db +@opindex mdb +@opindex mno-db +Enable (disable) generation of code using decrement and branch, +DBcond(D), instructions. This is enabled by default for the C4x. To be +on the safe side, this is disabled for the C3x, since the maximum +iteration count on the C3x is @math{2^{23} + 1} (but who iterates loops more than +@math{2^{23}} times on the C3x?). Note that GCC will try to reverse a loop so +that it can utilize the decrement and branch instruction, but will give +up if there is more than one memory reference in the loop. Thus a loop +where the loop counter is decremented can generate slightly more +efficient code, in cases where the RPTB instruction cannot be utilized. + +@item -mdp-isr-reload +@itemx -mparanoid +@opindex mdp-isr-reload +@opindex mparanoid +Force the DP register to be saved on entry to an interrupt service +routine (ISR), reloaded to point to the data section, and restored on +exit from the ISR@. This should not be required unless someone has +violated the small memory model by modifying the DP register, say within +an object library. + +@item -mmpyi +@itemx -mno-mpyi +@opindex mmpyi +@opindex mno-mpyi +For the C3x use the 24-bit MPYI instruction for integer multiplies +instead of a library call to guarantee 32-bit results. Note that if one +of the operands is a constant, then the multiplication will be performed +using shifts and adds. If the @option{-mmpyi} option is not specified for the C3x, +then squaring operations are performed inline instead of a library call. + +@item -mfast-fix +@itemx -mno-fast-fix +@opindex mfast-fix +@opindex mno-fast-fix +The C3x/C4x FIX instruction to convert a floating point value to an +integer value chooses the nearest integer less than or equal to the +floating point value rather than to the nearest integer. Thus if the +floating point number is negative, the result will be incorrectly +truncated an additional code is necessary to detect and correct this +case. This option can be used to disable generation of the additional +code required to correct the result. + +@item -mrptb +@itemx -mno-rptb +@opindex mrptb +@opindex mno-rptb +Enable (disable) generation of repeat block sequences using the RPTB +instruction for zero overhead looping. The RPTB construct is only used +for innermost loops that do not call functions or jump across the loop +boundaries. There is no advantage having nested RPTB loops due to the +overhead required to save and restore the RC, RS, and RE registers. +This is enabled by default with @option{-O2}. + +@item -mrpts=@var{count} +@itemx -mno-rpts +@opindex mrpts +@opindex mno-rpts +Enable (disable) the use of the single instruction repeat instruction +RPTS@. If a repeat block contains a single instruction, and the loop +count can be guaranteed to be less than the value @var{count}, GCC will +emit a RPTS instruction instead of a RPTB@. If no value is specified, +then a RPTS will be emitted even if the loop count cannot be determined +at compile time. Note that the repeated instruction following RPTS does +not have to be reloaded from memory each iteration, thus freeing up the +CPU buses for operands. However, since interrupts are blocked by this +instruction, it is disabled by default. + +@item -mloop-unsigned +@itemx -mno-loop-unsigned +@opindex mloop-unsigned +@opindex mno-loop-unsigned +The maximum iteration count when using RPTS and RPTB (and DB on the C40) +is @math{2^{31} + 1} since these instructions test if the iteration count is +negative to terminate the loop. If the iteration count is unsigned +there is a possibility than the @math{2^{31} + 1} maximum iteration count may be +exceeded. This switch allows an unsigned iteration count. + +@item -mti +@opindex mti +Try to emit an assembler syntax that the TI assembler (asm30) is happy +with. This also enforces compatibility with the API employed by the TI +C3x C compiler. For example, long doubles are passed as structures +rather than in floating point registers. + +@item -mregparm +@itemx -mmemparm +@opindex mregparm +@opindex mmemparm +Generate code that uses registers (stack) for passing arguments to functions. +By default, arguments are passed in registers where possible rather +than by pushing arguments on to the stack. + +@item -mparallel-insns +@itemx -mno-parallel-insns +@opindex mparallel-insns +@opindex mno-parallel-insns +Allow the generation of parallel instructions. This is enabled by +default with @option{-O2}. + +@item -mparallel-mpy +@itemx -mno-parallel-mpy +@opindex mparallel-mpy +@opindex mno-parallel-mpy +Allow the generation of MPY||ADD and MPY||SUB parallel instructions, +provided @option{-mparallel-insns} is also specified. These instructions have +tight register constraints which can pessimize the code generation +of large functions. + +@end table + +@node V850 Options +@subsection V850 Options +@cindex V850 Options + +These @samp{-m} options are defined for V850 implementations: + +@table @gcctabopt +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Treat all calls as being far away (near). If calls are assumed to be +far away, the compiler will always load the functions address up into a +register, and call indirect through the pointer. + +@item -mno-ep +@itemx -mep +@opindex mno-ep +@opindex mep +Do not optimize (do optimize) basic blocks that use the same index +pointer 4 or more times to copy pointer into the @code{ep} register, and +use the shorter @code{sld} and @code{sst} instructions. The @option{-mep} +option is on by default if you optimize. + +@item -mno-prolog-function +@itemx -mprolog-function +@opindex mno-prolog-function +@opindex mprolog-function +Do not use (do use) external functions to save and restore registers +at the prologue and epilogue of a function. The external functions +are slower, but use less code space if more than one function saves +the same number of registers. The @option{-mprolog-function} option +is on by default if you optimize. + +@item -mspace +@opindex mspace +Try to make the code as small as possible. At present, this just turns +on the @option{-mep} and @option{-mprolog-function} options. + +@item -mtda=@var{n} +@opindex mtda +Put static or global variables whose size is @var{n} bytes or less into +the tiny data area that register @code{ep} points to. The tiny data +area can hold up to 256 bytes in total (128 bytes for byte references). + +@item -msda=@var{n} +@opindex msda +Put static or global variables whose size is @var{n} bytes or less into +the small data area that register @code{gp} points to. The small data +area can hold up to 64 kilobytes. + +@item -mzda=@var{n} +@opindex mzda +Put static or global variables whose size is @var{n} bytes or less into +the first 32 kilobytes of memory. + +@item -mv850 +@opindex mv850 +Specify that the target processor is the V850. + +@item -mbig-switch +@opindex mbig-switch +Generate code suitable for big switch tables. Use this option only if +the assembler/linker complain about out of range branches within a switch +table. + +@item -mapp-regs +@opindex mapp-regs +This option will cause r2 and r5 to be used in the code generated by +the compiler. This setting is the default. + +@item -mno-app-regs +@opindex mno-app-regs +This option will cause r2 and r5 to be treated as fixed registers. + +@item -mv850e1 +@opindex mv850e1 +Specify that the target processor is the V850E1. The preprocessor +constants @samp{__v850e1__} and @samp{__v850e__} will be defined if +this option is used. + +@item -mv850e +@opindex mv850e +Specify that the target processor is the V850E@. The preprocessor +constant @samp{__v850e__} will be defined if this option is used. + +If neither @option{-mv850} nor @option{-mv850e} nor @option{-mv850e1} +are defined then a default target processor will be chosen and the +relevant @samp{__v850*__} preprocessor constant will be defined. + +The preprocessor constants @samp{__v850} and @samp{__v851__} are always +defined, regardless of which processor variant is the target. + +@item -mdisable-callt +@opindex mdisable-callt +This option will suppress generation of the CALLT instruction for the +v850e and v850e1 flavors of the v850 architecture. The default is +@option{-mno-disable-callt} which allows the CALLT instruction to be used. + +@end table + +@node VAX Options +@subsection VAX Options +@cindex VAX options + +These @samp{-m} options are defined for the VAX: + +@table @gcctabopt +@item -munix +@opindex munix +Do not output certain jump instructions (@code{aobleq} and so on) +that the Unix assembler for the VAX cannot handle across long +ranges. + +@item -mgnu +@opindex mgnu +Do output those jump instructions, on the assumption that you +will assemble with the GNU assembler. + +@item -mg +@opindex mg +Output code for g-format floating point numbers instead of d-format. +@end table + +@node x86-64 Options +@subsection x86-64 Options +@cindex x86-64 options + +These are listed under @xref{i386 and x86-64 Options}. + +@node Xstormy16 Options +@subsection Xstormy16 Options +@cindex Xstormy16 Options + +These options are defined for Xstormy16: + +@table @gcctabopt +@item -msim +@opindex msim +Choose startup files and linker script suitable for the simulator. +@end table + +@node Xtensa Options +@subsection Xtensa Options +@cindex Xtensa Options + +These options are supported for Xtensa targets: + +@table @gcctabopt +@item -mconst16 +@itemx -mno-const16 +@opindex mconst16 +@opindex mno-const16 +Enable or disable use of @code{CONST16} instructions for loading +constant values. The @code{CONST16} instruction is currently not a +standard option from Tensilica. When enabled, @code{CONST16} +instructions are always used in place of the standard @code{L32R} +instructions. The use of @code{CONST16} is enabled by default only if +the @code{L32R} instruction is not available. + +@item -mfused-madd +@itemx -mno-fused-madd +@opindex mfused-madd +@opindex mno-fused-madd +Enable or disable use of fused multiply/add and multiply/subtract +instructions in the floating-point option. This has no effect if the +floating-point option is not also enabled. Disabling fused multiply/add +and multiply/subtract instructions forces the compiler to use separate +instructions for the multiply and add/subtract operations. This may be +desirable in some cases where strict IEEE 754-compliant results are +required: the fused multiply add/subtract instructions do not round the +intermediate result, thereby producing results with @emph{more} bits of +precision than specified by the IEEE standard. Disabling fused multiply +add/subtract instructions also ensures that the program output is not +sensitive to the compiler's ability to combine multiply and add/subtract +operations. + +@item -mtext-section-literals +@itemx -mno-text-section-literals +@opindex mtext-section-literals +@opindex mno-text-section-literals +Control the treatment of literal pools. The default is +@option{-mno-text-section-literals}, which places literals in a separate +section in the output file. This allows the literal pool to be placed +in a data RAM/ROM, and it also allows the linker to combine literal +pools from separate object files to remove redundant literals and +improve code size. With @option{-mtext-section-literals}, the literals +are interspersed in the text section in order to keep them as close as +possible to their references. This may be necessary for large assembly +files. + +@item -mtarget-align +@itemx -mno-target-align +@opindex mtarget-align +@opindex mno-target-align +When this option is enabled, GCC instructs the assembler to +automatically align instructions to reduce branch penalties at the +expense of some code density. The assembler attempts to widen density +instructions to align branch targets and the instructions following call +instructions. If there are not enough preceding safe density +instructions to align a target, no widening will be performed. The +default is @option{-mtarget-align}. These options do not affect the +treatment of auto-aligned instructions like @code{LOOP}, which the +assembler will always align, either by widening density instructions or +by inserting no-op instructions. + +@item -mlongcalls +@itemx -mno-longcalls +@opindex mlongcalls +@opindex mno-longcalls +When this option is enabled, GCC instructs the assembler to translate +direct calls to indirect calls unless it can determine that the target +of a direct call is in the range allowed by the call instruction. This +translation typically occurs for calls to functions in other source +files. Specifically, the assembler translates a direct @code{CALL} +instruction into an @code{L32R} followed by a @code{CALLX} instruction. +The default is @option{-mno-longcalls}. This option should be used in +programs where the call target can potentially be out of range. This +option is implemented in the assembler, not the compiler, so the +assembly code generated by GCC will still show direct call +instructions---look at the disassembled object code to see the actual +instructions. Note that the assembler will use an indirect call for +every cross-file call, not just those that really will be out of range. +@end table + +@node zSeries Options +@subsection zSeries Options +@cindex zSeries options + +These are listed under @xref{S/390 and zSeries Options}. +@c APPLE LOCAL prune man page +@end ignore + +@node Code Gen Options +@section Options for Code Generation Conventions +@cindex code generation conventions +@cindex options, code generation +@cindex run-time options + +These machine-independent options control the interface conventions +used in code generation. + +Most of them have both positive and negative forms; the negative form +of @option{-ffoo} would be @option{-fno-foo}. In the table below, only +one of the forms is listed---the one which is not the default. You +can figure out the other form by either removing @samp{no-} or adding +it. + +@table @gcctabopt +@item -fbounds-check +@opindex fbounds-check +For front-ends that support it, generate additional code to check that +indices used to access arrays are within the declared range. This is +currently only supported by the Java and Fortran front-ends, where +this option defaults to true and false respectively. + +@c APPLE LOCAL prune man page 5547358 +@ignore +@item -ftrapv +@opindex ftrapv +This option generates traps for signed overflow on addition, subtraction, +multiplication operations. +@c APPLE LOCAL prune man page 5547358 +@end ignore + +@item -fwrapv +@opindex fwrapv +This option instructs the compiler to assume that signed arithmetic +overflow of addition, subtraction and multiplication wraps around +using twos-complement representation. This flag enables some optimizations +and disables others. This option is enabled by default for the Java +front-end, as required by the Java language specification. + +@item -fexceptions +@opindex fexceptions +Enable exception handling. Generates extra code needed to propagate +exceptions. For some targets, this implies GCC will generate frame +unwind information for all functions, which can produce significant data +size overhead, although it does not affect execution. If you do not +specify this option, GCC will enable it by default for languages like +C++ which normally require exception handling, and disable it for +languages like C that do not normally require it. However, you may need +to enable this option when compiling C code that needs to interoperate +properly with exception handlers written in C++. You may also wish to +disable this option if you are compiling older C++ programs that don't +use exception handling. + +@item -fnon-call-exceptions +@opindex fnon-call-exceptions +Generate code that allows trapping instructions to throw exceptions. +Note that this requires platform-specific runtime support that does +not exist everywhere. Moreover, it only allows @emph{trapping} +instructions to throw exceptions, i.e.@: memory references or floating +point instructions. It does not allow exceptions to be thrown from +arbitrary signal handlers such as @code{SIGALRM}. + +@item -funwind-tables +@opindex funwind-tables +Similar to @option{-fexceptions}, except that it will just generate any needed +static data, but will not affect the generated code in any other way. +You will normally not enable this option; instead, a language processor +that needs this handling would enable it on your behalf. + +@item -fasynchronous-unwind-tables +@opindex fasynchronous-unwind-tables +Generate unwind table in dwarf2 format, if supported by target machine. The +table is exact at each instruction boundary, so it can be used for stack +unwinding from asynchronous events (such as debugger or garbage collector). + +@item -fpcc-struct-return +@opindex fpcc-struct-return +Return ``short'' @code{struct} and @code{union} values in memory like +longer ones, rather than in registers. This convention is less +efficient, but it has the advantage of allowing intercallability between +GCC-compiled files and files compiled with other compilers, particularly +the Portable C Compiler (pcc). + +The precise convention for returning structures in memory depends +on the target configuration macros. + +Short structures and unions are those whose size and alignment match +that of some integer type. + +@strong{Warning:} code compiled with the @option{-fpcc-struct-return} +switch is not binary compatible with code compiled with the +@option{-freg-struct-return} switch. +Use it to conform to a non-default application binary interface. + +@item -freg-struct-return +@opindex freg-struct-return +Return @code{struct} and @code{union} values in registers when possible. +This is more efficient for small structures than +@option{-fpcc-struct-return}. + +If you specify neither @option{-fpcc-struct-return} nor +@option{-freg-struct-return}, GCC defaults to whichever convention is +standard for the target. If there is no standard convention, GCC +defaults to @option{-fpcc-struct-return}, except on targets where GCC is +the principal compiler. In those cases, we can choose the standard, and +we chose the more efficient register return alternative. + +@strong{Warning:} code compiled with the @option{-freg-struct-return} +switch is not binary compatible with code compiled with the +@option{-fpcc-struct-return} switch. +Use it to conform to a non-default application binary interface. + +@item -fshort-enums +@opindex fshort-enums +Allocate to an @code{enum} type only as many bytes as it needs for the +declared range of possible values. Specifically, the @code{enum} type +will be equivalent to the smallest integer type which has enough room. + +@strong{Warning:} the @option{-fshort-enums} switch causes GCC to generate +code that is not binary compatible with code generated without that switch. +Use it to conform to a non-default application binary interface. + +@item -fshort-double +@opindex fshort-double +Use the same size for @code{double} as for @code{float}. + +@strong{Warning:} the @option{-fshort-double} switch causes GCC to generate +code that is not binary compatible with code generated without that switch. +Use it to conform to a non-default application binary interface. + +@item -fshort-wchar +@opindex fshort-wchar +Override the underlying type for @samp{wchar_t} to be @samp{short +unsigned int} instead of the default for the target. This option is +useful for building programs to run under WINE@. + +@strong{Warning:} the @option{-fshort-wchar} switch causes GCC to generate +code that is not binary compatible with code generated without that switch. +Use it to conform to a non-default application binary interface. + +@item -fno-common +@opindex fno-common +In C, allocate even uninitialized global variables in the data section of the +object file, rather than generating them as common blocks. This has the +effect that if the same variable is declared (without @code{extern}) in +two different compilations, you will get an error when you link them. +The only reason this might be useful is if you wish to verify that the +program will work on other systems which always work this way. + +@item -fno-ident +@opindex fno-ident +Ignore the @samp{#ident} directive. + +@item -finhibit-size-directive +@opindex finhibit-size-directive +Don't output a @code{.size} assembler directive, or anything else that +would cause trouble if the function is split in the middle, and the +two halves are placed at locations far apart in memory. This option is +used when compiling @file{crtstuff.c}; you should not need to use it +for anything else. + +@item -fverbose-asm +@opindex fverbose-asm +Put extra commentary information in the generated assembly code to +make it more readable. This option is generally only of use to those +who actually need to read the generated assembly code (perhaps while +debugging the compiler itself). + +@option{-fno-verbose-asm}, the default, causes the +extra information to be omitted and is useful when comparing two assembler +files. + +@item -fpic +@opindex fpic +@cindex global offset table +@cindex PIC +Generate position-independent code (PIC) suitable for use in a shared +library, if supported for the target machine. Such code accesses all +constant addresses through a global offset table (GOT)@. The dynamic +loader resolves the GOT entries when the program starts (the dynamic +loader is not part of GCC; it is part of the operating system). If +the GOT size for the linked executable exceeds a machine-specific +maximum size, you get an error message from the linker indicating that +@option{-fpic} does not work; in that case, recompile with @option{-fPIC} +instead. (These maximums are 8k on the SPARC and 32k +on the m68k and RS/6000. The 386 has no such limit.) + +Position-independent code requires special support, and therefore works +only on certain machines. For the 386, GCC supports PIC for System V +but not for the Sun 386i. Code generated for the IBM RS/6000 is always +position-independent. + +When this flag is set, the macros @code{__pic__} and @code{__PIC__} +are defined to 1. + +@item -fPIC +@opindex fPIC +If supported for the target machine, emit position-independent code, +suitable for dynamic linking and avoiding any limit on the size of the +global offset table. This option makes a difference on the m68k, +PowerPC and SPARC@. + +Position-independent code requires special support, and therefore works +only on certain machines. + +When this flag is set, the macros @code{__pic__} and @code{__PIC__} +are defined to 2. + +@c APPLE LOCAL begin manual +@option{-fPIC} is the default on Darwin and Mac OS X. +@c APPLE LOCAL end manual + +@item -fpie +@itemx -fPIE +@opindex fpie +@opindex fPIE +These options are similar to @option{-fpic} and @option{-fPIC}, but +generated position independent code can be only linked into executables. +Usually these options are used when @option{-pie} GCC option will be +used during linking. + +@item -fno-jump-tables +@opindex fno-jump-tables +Do not use jump tables for switch statements even where it would be +more efficient than other code generation strategies. This option is +of use in conjunction with @option{-fpic} or @option{-fPIC} for +building code which forms part of a dynamic linker and cannot +reference the address of a jump table. On some targets, jump tables +do not require a GOT and this option is not needed. + +@item -ffixed-@var{reg} +@opindex ffixed +Treat the register named @var{reg} as a fixed register; generated code +should never refer to it (except perhaps as a stack pointer, frame +pointer or in some other fixed role). + +@var{reg} must be the name of a register. The register names accepted +are machine-specific and are defined in the @code{REGISTER_NAMES} +macro in the machine description macro file. + +This flag does not have a negative form, because it specifies a +three-way choice. + +@item -fcall-used-@var{reg} +@opindex fcall-used +Treat the register named @var{reg} as an allocable register that is +clobbered by function calls. It may be allocated for temporaries or +variables that do not live across a call. Functions compiled this way +will not save and restore the register @var{reg}. + +It is an error to used this flag with the frame pointer or stack pointer. +Use of this flag for other registers that have fixed pervasive roles in +the machine's execution model will produce disastrous results. + +This flag does not have a negative form, because it specifies a +three-way choice. + +@item -fcall-saved-@var{reg} +@opindex fcall-saved +Treat the register named @var{reg} as an allocable register saved by +functions. It may be allocated even for temporaries or variables that +live across a call. Functions compiled this way will save and restore +the register @var{reg} if they use it. + +It is an error to used this flag with the frame pointer or stack pointer. +Use of this flag for other registers that have fixed pervasive roles in +the machine's execution model will produce disastrous results. + +A different sort of disaster will result from the use of this flag for +a register in which function values may be returned. + +This flag does not have a negative form, because it specifies a +three-way choice. + +@item -fpack-struct[=@var{n}] +@opindex fpack-struct +Without a value specified, pack all structure members together without +holes. When a value is specified (which must be a small power of two), pack +structure members according to this value, representing the maximum +alignment (that is, objects with default alignment requirements larger than +this will be output potentially unaligned at the next fitting location. + +@strong{Warning:} the @option{-fpack-struct} switch causes GCC to generate +code that is not binary compatible with code generated without that switch. +Additionally, it makes the code suboptimal. +Use it to conform to a non-default application binary interface. + +@item -finstrument-functions +@opindex finstrument-functions +Generate instrumentation calls for entry and exit to functions. Just +after function entry and just before function exit, the following +profiling functions will be called with the address of the current +function and its call site. (On some platforms, +@code{__builtin_return_address} does not work beyond the current +function, so the call site information may not be available to the +profiling functions otherwise.) + +@smallexample +void __cyg_profile_func_enter (void *this_fn, + void *call_site); +void __cyg_profile_func_exit (void *this_fn, + void *call_site); +@end smallexample + +The first argument is the address of the start of the current function, +which may be looked up exactly in the symbol table. + +This instrumentation is also done for functions expanded inline in other +functions. The profiling calls will indicate where, conceptually, the +inline function is entered and exited. This means that addressable +versions of such functions must be available. If all your uses of a +function are expanded inline, this may mean an additional expansion of +code size. If you use @samp{extern inline} in your C code, an +addressable version of such functions must be provided. (This is +normally the case anyways, but if you get lucky and the optimizer always +expands the functions inline, you might have gotten away without +providing static copies.) + +A function may be given the attribute @code{no_instrument_function}, in +which case this instrumentation will not be done. This can be used, for +example, for the profiling functions listed above, high-priority +interrupt routines, and any functions from which the profiling functions +cannot safely be called (perhaps signal handlers, if the profiling +routines generate output or allocate memory). + +@item -fstack-check +@opindex fstack-check +Generate code to verify that you do not go beyond the boundary of the +stack. You should specify this flag if you are running in an +environment with multiple threads, but only rarely need to specify it in +a single-threaded environment since stack overflow is automatically +detected on nearly all systems if there is only one stack. + +Note that this switch does not actually cause checking to be done; the +operating system must do that. The switch causes generation of code +to ensure that the operating system sees the stack being extended. + +@item -fstack-limit-register=@var{reg} +@itemx -fstack-limit-symbol=@var{sym} +@itemx -fno-stack-limit +@opindex fstack-limit-register +@opindex fstack-limit-symbol +@opindex fno-stack-limit +Generate code to ensure that the stack does not grow beyond a certain value, +either the value of a register or the address of a symbol. If the stack +would grow beyond the value, a signal is raised. For most targets, +the signal is raised before the stack overruns the boundary, so +it is possible to catch the signal without taking special precautions. + +For instance, if the stack starts at absolute address @samp{0x80000000} +and grows downwards, you can use the flags +@option{-fstack-limit-symbol=__stack_limit} and +@option{-Wl,--defsym,__stack_limit=0x7ffe0000} to enforce a stack limit +of 128KB@. Note that this may only work with the GNU linker. + +@cindex aliasing of parameters +@cindex parameters, aliased +@item -fargument-alias +@itemx -fargument-noalias +@itemx -fargument-noalias-global +@itemx -fargument-noalias-anything +@opindex fargument-alias +@opindex fargument-noalias +@opindex fargument-noalias-global +@opindex fargument-noalias-anything +Specify the possible relationships among parameters and between +parameters and global data. + +@option{-fargument-alias} specifies that arguments (parameters) may +alias each other and may alias global storage.@* +@option{-fargument-noalias} specifies that arguments do not alias +each other, but may alias global storage.@* +@option{-fargument-noalias-global} specifies that arguments do not +alias each other and do not alias global storage. +@option{-fargument-noalias-anything} specifies that arguments do not +alias any other storage. + +Each language will automatically use whatever option is required by +the language standard. You should not need to use these options yourself. + +@item -fleading-underscore +@opindex fleading-underscore +This option and its counterpart, @option{-fno-leading-underscore}, forcibly +change the way C symbols are represented in the object file. One use +is to help link with legacy assembly code. + +@strong{Warning:} the @option{-fleading-underscore} switch causes GCC to +generate code that is not binary compatible with code generated without that +switch. Use it to conform to a non-default application binary interface. +Not all targets provide complete support for this switch. + +@item -ftls-model=@var{model} +Alter the thread-local storage model to be used (@pxref{Thread-Local}). +The @var{model} argument should be one of @code{global-dynamic}, +@code{local-dynamic}, @code{initial-exec} or @code{local-exec}. + +The default without @option{-fpic} is @code{initial-exec}; with +@option{-fpic} the default is @code{global-dynamic}. + +@item -fvisibility=@var{default|internal|hidden|protected} +@opindex fvisibility +Set the default ELF image symbol visibility to the specified option---all +symbols will be marked with this unless overridden within the code. +Using this feature can very substantially improve linking and +load times of shared object libraries, produce more optimized +code, provide near-perfect API export and prevent symbol clashes. +It is @strong{strongly} recommended that you use this in any shared objects +you distribute. + +Despite the nomenclature, @code{default} always means public ie; +available to be linked against from outside the shared object. +@code{protected} and @code{internal} are pretty useless in real-world +usage so the only other commonly used option will be @code{hidden}. +The default if @option{-fvisibility} isn't specified is +@code{default}, i.e., make every +symbol public---this causes the same behavior as previous versions of +GCC@. + +A good explanation of the benefits offered by ensuring ELF +symbols have the correct visibility is given by ``How To Write +Shared Libraries'' by Ulrich Drepper (which can be found at +@w{@uref{http://people.redhat.com/~drepper/}})---however a superior +solution made possible by this option to marking things hidden when +the default is public is to make the default hidden and mark things +public. This is the norm with DLL's on Windows and with @option{-fvisibility=hidden} +and @code{__attribute__ ((visibility("default")))} instead of +@code{__declspec(dllexport)} you get almost identical semantics with +identical syntax. This is a great boon to those working with +cross-platform projects. + +For those adding visibility support to existing code, you may find +@samp{#pragma GCC visibility} of use. This works by you enclosing +the declarations you wish to set visibility for with (for example) +@samp{#pragma GCC visibility push(hidden)} and +@samp{#pragma GCC visibility pop}. +Bear in mind that symbol visibility should be viewed @strong{as +part of the API interface contract} and thus all new code should +always specify visibility when it is not the default ie; declarations +only for use within the local DSO should @strong{always} be marked explicitly +as hidden as so to avoid PLT indirection overheads---making this +abundantly clear also aids readability and self-documentation of the code. +Note that due to ISO C++ specification requirements, operator new and +operator delete must always be of default visibility. + +Be aware that headers from outside your project, in particular system +headers and headers from any other library you use, may not be +expecting to be compiled with visibility other than the default. You +may need to explicitly say @samp{#pragma GCC visibility push(default)} +before including any such headers. + +@samp{extern} declarations are not affected by @samp{-fvisibility}, so +a lot of code can be recompiled with @samp{-fvisibility=hidden} with +no modifications. However, this means that calls to @samp{extern} +functions with no explicit visibility will use the PLT, so it is more +effective to use @samp{__attribute ((visibility))} and/or +@samp{#pragma GCC visibility} to tell the compiler which @samp{extern} +declarations should be treated as hidden. + +Note that @samp{-fvisibility} does affect C++ vague linkage +entities. This means that, for instance, an exception class that will +be thrown between DSOs must be explicitly marked with default +visibility so that the @samp{type_info} nodes will be unified between +the DSOs. + +An overview of these techniques, their benefits and how to use them +is at @w{@uref{http://gcc.gnu.org/wiki/Visibility}}. + +@end table + +@c man end + +@node Environment Variables +@section Environment Variables Affecting GCC +@cindex environment variables + +@c man begin ENVIRONMENT +This section describes several environment variables that affect how GCC +operates. Some of them work by specifying directories or prefixes to use +when searching for various kinds of files. Some are used to specify other +aspects of the compilation environment. + +Note that you can also specify places to search using options such as +@option{-B}, @option{-I} and @option{-L} (@pxref{Directory Options}). These +take precedence over places specified using environment variables, which +in turn take precedence over those specified by the configuration of GCC@. +@xref{Driver,, Controlling the Compilation Driver @file{gcc}, gccint, +GNU Compiler Collection (GCC) Internals}. + +@table @env +@item LANG +@itemx LC_CTYPE +@c @itemx LC_COLLATE +@itemx LC_MESSAGES +@c @itemx LC_MONETARY +@c @itemx LC_NUMERIC +@c @itemx LC_TIME +@itemx LC_ALL +@findex LANG +@findex LC_CTYPE +@c @findex LC_COLLATE +@findex LC_MESSAGES +@c @findex LC_MONETARY +@c @findex LC_NUMERIC +@c @findex LC_TIME +@findex LC_ALL +@cindex locale +These environment variables control the way that GCC uses +localization information that allow GCC to work with different +national conventions. GCC inspects the locale categories +@env{LC_CTYPE} and @env{LC_MESSAGES} if it has been configured to do +so. These locale categories can be set to any value supported by your +installation. A typical value is @samp{en_GB.UTF-8} for English in the United +Kingdom encoded in UTF-8. + +The @env{LC_CTYPE} environment variable specifies character +classification. GCC uses it to determine the character boundaries in +a string; this is needed for some multibyte encodings that contain quote +and escape characters that would otherwise be interpreted as a string +end or escape. + +The @env{LC_MESSAGES} environment variable specifies the language to +use in diagnostic messages. + +If the @env{LC_ALL} environment variable is set, it overrides the value +of @env{LC_CTYPE} and @env{LC_MESSAGES}; otherwise, @env{LC_CTYPE} +and @env{LC_MESSAGES} default to the value of the @env{LANG} +environment variable. If none of these variables are set, GCC +defaults to traditional C English behavior. + +@item TMPDIR +@findex TMPDIR +If @env{TMPDIR} is set, it specifies the directory to use for temporary +files. GCC uses temporary files to hold the output of one stage of +compilation which is to be used as input to the next stage: for example, +the output of the preprocessor, which is the input to the compiler +proper. + +@item GCC_EXEC_PREFIX +@findex GCC_EXEC_PREFIX +If @env{GCC_EXEC_PREFIX} is set, it specifies a prefix to use in the +names of the subprograms executed by the compiler. No slash is added +when this prefix is combined with the name of a subprogram, but you can +specify a prefix that ends with a slash if you wish. + +If @env{GCC_EXEC_PREFIX} is not set, GCC will attempt to figure out +an appropriate prefix to use based on the pathname it was invoked with. + +If GCC cannot find the subprogram using the specified prefix, it +tries looking in the usual places for the subprogram. + +The default value of @env{GCC_EXEC_PREFIX} is +@file{@var{prefix}/lib/gcc/} where @var{prefix} is the value +of @code{prefix} when you ran the @file{configure} script. + +Other prefixes specified with @option{-B} take precedence over this prefix. + +This prefix is also used for finding files such as @file{crt0.o} that are +used for linking. + +In addition, the prefix is used in an unusual way in finding the +directories to search for header files. For each of the standard +directories whose name normally begins with @samp{/usr/local/lib/gcc} +(more precisely, with the value of @env{GCC_INCLUDE_DIR}), GCC tries +replacing that beginning with the specified prefix to produce an +alternate directory name. Thus, with @option{-Bfoo/}, GCC will search +@file{foo/bar} where it would normally search @file{/usr/local/lib/bar}. +These alternate directories are searched first; the standard directories +come next. + +@item COMPILER_PATH +@findex COMPILER_PATH +The value of @env{COMPILER_PATH} is a colon-separated list of +directories, much like @env{PATH}. GCC tries the directories thus +specified when searching for subprograms, if it can't find the +subprograms using @env{GCC_EXEC_PREFIX}. + +@item LIBRARY_PATH +@findex LIBRARY_PATH +The value of @env{LIBRARY_PATH} is a colon-separated list of +directories, much like @env{PATH}. When configured as a native compiler, +GCC tries the directories thus specified when searching for special +linker files, if it can't find them using @env{GCC_EXEC_PREFIX}. Linking +using GCC also uses these directories when searching for ordinary +libraries for the @option{-l} option (but directories specified with +@option{-L} come first). + +@item LANG +@findex LANG +@cindex locale definition +This variable is used to pass locale information to the compiler. One way in +which this information is used is to determine the character set to be used +when character literals, string literals and comments are parsed in C and C++. +When the compiler is configured to allow multibyte characters, +the following values for @env{LANG} are recognized: + +@table @samp +@item C-JIS +Recognize JIS characters. +@item C-SJIS +Recognize SJIS characters. +@item C-EUCJP +Recognize EUCJP characters. +@end table + +If @env{LANG} is not defined, or if it has some other value, then the +compiler will use mblen and mbtowc as defined by the default locale to +recognize and translate multibyte characters. + +@c APPLE LOCAL begin ARM 5905142 +@item MACOSX_DEPLOYMENT_TARGET +@itemx IPHONEOS_DEPLOYMENT_TARGET +These variables are used to set the target OS version, as described +for command-line options @option{-mmacosx-version-min} and +@option{-miphoneos-version-min}. Only one OS version can be specified +per architecture, with @env{MACOSX_DEPLOYMENT_TARGET} taking precedence +on non-ARM targets and @env{IPHONEOS_DEPLOYMENT_TARGET} taking +precedence on ARM targets. + +If either command-line option @option{-mmacosx-version-min} or +@option{-miphoneos-version-min} is specified, both of these +environment variables are ignored. +@c APPLE LOCAL end ARM 5905142 +@end table + +@noindent +Some additional environments variables affect the behavior of the +preprocessor. + +@include cppenv.texi + +@c man end + +@node Precompiled Headers +@section Using Precompiled Headers +@cindex precompiled headers +@cindex speed of compilation + +Often large projects have many header files that are included in every +source file. The time the compiler takes to process these header files +over and over again can account for nearly all of the time required to +build the project. To make builds faster, GCC allows users to +`precompile' a header file; then, if builds can use the precompiled +header file they will be much faster. + +To create a precompiled header file, simply compile it as you would any +other file, if necessary using the @option{-x} option to make the driver +treat it as a C or C++ header file. You will probably want to use a +tool like @command{make} to keep the precompiled header up-to-date when +the headers it contains change. + +A precompiled header file will be searched for when @code{#include} is +seen in the compilation. As it searches for the included file +(@pxref{Search Path,,Search Path,cpp,The C Preprocessor}) the +compiler looks for a precompiled header in each directory just before it +looks for the include file in that directory. The name searched for is +the name specified in the @code{#include} with @samp{.gch} appended. If +the precompiled header file can't be used, it is ignored. + +For instance, if you have @code{#include "all.h"}, and you have +@file{all.h.gch} in the same directory as @file{all.h}, then the +precompiled header file will be used if possible, and the original +header will be used otherwise. + +Alternatively, you might decide to put the precompiled header file in a +directory and use @option{-I} to ensure that directory is searched +before (or instead of) the directory containing the original header. +Then, if you want to check that the precompiled header file is always +used, you can put a file of the same name as the original header in this +directory containing an @code{#error} command. + +This also works with @option{-include}. So yet another way to use +precompiled headers, good for projects not designed with precompiled +header files in mind, is to simply take most of the header files used by +a project, include them from another header file, precompile that header +file, and @option{-include} the precompiled header. If the header files +have guards against multiple inclusion, they will be skipped because +they've already been included (in the precompiled header). + +If you need to precompile the same header file for different +languages, targets, or compiler options, you can instead make a +@emph{directory} named like @file{all.h.gch}, and put each precompiled +header in the directory, perhaps using @option{-o}. It doesn't matter +what you call the files in the directory, every precompiled header in +the directory will be considered. The first precompiled header +encountered in the directory that is valid for this compilation will +be used; they're searched in no particular order. + +There are many other possibilities, limited only by your imagination, +good sense, and the constraints of your build system. + +A precompiled header file can be used only when these conditions apply: + +@itemize +@item +Only one precompiled header can be used in a particular compilation. + +@item +A precompiled header can't be used once the first C token is seen. You +can have preprocessor directives before a precompiled header; you can +even include a precompiled header from inside another header, so long as +there are no C tokens before the @code{#include}. + +@item +The precompiled header file must be produced for the same language as +the current compilation. You can't use a C precompiled header for a C++ +compilation. + +@item +The precompiled header file must have been produced by the same compiler +binary as the current compilation is using. + +@item +Any macros defined before the precompiled header is included must +either be defined in the same way as when the precompiled header was +generated, or must not affect the precompiled header, which usually +means that they don't appear in the precompiled header at all. + +The @option{-D} option is one way to define a macro before a +precompiled header is included; using a @code{#define} can also do it. +There are also some options that define macros implicitly, like +@option{-O} and @option{-Wdeprecated}; the same rule applies to macros +defined this way. + +@item If debugging information is output when using the precompiled +header, using @option{-g} or similar, the same kind of debugging information +must have been output when building the precompiled header. However, +a precompiled header built using @option{-g} can be used in a compilation +when no debugging information is being output. + +@item The same @option{-m} options must generally be used when building +and using the precompiled header. @xref{Submodel Options}, +for any cases where this rule is relaxed. + +@item Each of the following options must be the same when building and using +the precompiled header: + +@gccoptlist{-fexceptions -funit-at-a-time} + +@item +Some other command-line options starting with @option{-f}, +@option{-p}, or @option{-O} must be defined in the same way as when +the precompiled header was generated. At present, it's not clear +which options are safe to change and which are not; the safest choice +is to use exactly the same options when generating and using the +precompiled header. The following are known to be safe: + +@gccoptlist{-fmessage-length= -fpreprocessed +-fsched-interblock -fsched-spec -fsched-spec-load -fsched-spec-load-dangerous +-fsched-verbose=<number> -fschedule-insns -fvisibility= +-pedantic-errors} + +@end itemize + +For all of these except the last, the compiler will automatically +ignore the precompiled header if the conditions aren't met. If you +find an option combination that doesn't work and doesn't cause the +precompiled header to be ignored, please consider filing a bug report, +see @ref{Bugs}. + +If you do use differing options when generating and using the +precompiled header, the actual behavior will be a mixture of the +behavior for the options. For instance, if you use @option{-g} to +generate the precompiled header but not when using it, you may or may +not get debugging information for routines in the precompiled header. + +@node Running Protoize +@section Running Protoize + +The program @code{protoize} is an optional part of GCC@. You can use +it to add prototypes to a program, thus converting the program to ISO +C in one respect. The companion program @code{unprotoize} does the +reverse: it removes argument types from any prototypes that are found. + +When you run these programs, you must specify a set of source files as +command line arguments. The conversion programs start out by compiling +these files to see what functions they define. The information gathered +about a file @var{foo} is saved in a file named @file{@var{foo}.X}. + +After scanning comes actual conversion. The specified files are all +eligible to be converted; any files they include (whether sources or +just headers) are eligible as well. + +But not all the eligible files are converted. By default, +@code{protoize} and @code{unprotoize} convert only source and header +files in the current directory. You can specify additional directories +whose files should be converted with the @option{-d @var{directory}} +option. You can also specify particular files to exclude with the +@option{-x @var{file}} option. A file is converted if it is eligible, its +directory name matches one of the specified directory names, and its +name within the directory has not been excluded. + +Basic conversion with @code{protoize} consists of rewriting most +function definitions and function declarations to specify the types of +the arguments. The only ones not rewritten are those for varargs +functions. + +@code{protoize} optionally inserts prototype declarations at the +beginning of the source file, to make them available for any calls that +precede the function's definition. Or it can insert prototype +declarations with block scope in the blocks where undeclared functions +are called. + +Basic conversion with @code{unprotoize} consists of rewriting most +function declarations to remove any argument types, and rewriting +function definitions to the old-style pre-ISO form. + +Both conversion programs print a warning for any function declaration or +definition that they can't convert. You can suppress these warnings +with @option{-q}. + +The output from @code{protoize} or @code{unprotoize} replaces the +original source file. The original file is renamed to a name ending +with @samp{.save} (for DOS, the saved filename ends in @samp{.sav} +without the original @samp{.c} suffix). If the @samp{.save} (@samp{.sav} +for DOS) file already exists, then the source file is simply discarded. + +@code{protoize} and @code{unprotoize} both depend on GCC itself to +scan the program and collect information about the functions it uses. +So neither of these programs will work until GCC is installed. + +Here is a table of the options you can use with @code{protoize} and +@code{unprotoize}. Each option works with both programs unless +otherwise stated. + +@table @code +@item -B @var{directory} +Look for the file @file{SYSCALLS.c.X} in @var{directory}, instead of the +usual directory (normally @file{/usr/local/lib}). This file contains +prototype information about standard system functions. This option +applies only to @code{protoize}. + +@item -c @var{compilation-options} +Use @var{compilation-options} as the options when running @command{gcc} to +produce the @samp{.X} files. The special option @option{-aux-info} is +always passed in addition, to tell @command{gcc} to write a @samp{.X} file. + +Note that the compilation options must be given as a single argument to +@code{protoize} or @code{unprotoize}. If you want to specify several +@command{gcc} options, you must quote the entire set of compilation options +to make them a single word in the shell. + +There are certain @command{gcc} arguments that you cannot use, because they +would produce the wrong kind of output. These include @option{-g}, +@option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in +the @var{compilation-options}, they are ignored. + +@item -C +Rename files to end in @samp{.C} (@samp{.cc} for DOS-based file +systems) instead of @samp{.c}. This is convenient if you are converting +a C program to C++. This option applies only to @code{protoize}. + +@item -g +Add explicit global declarations. This means inserting explicit +declarations at the beginning of each source file for each function +that is called in the file and was not declared. These declarations +precede the first function definition that contains a call to an +undeclared function. This option applies only to @code{protoize}. + +@item -i @var{string} +Indent old-style parameter declarations with the string @var{string}. +This option applies only to @code{protoize}. + +@code{unprotoize} converts prototyped function definitions to old-style +function definitions, where the arguments are declared between the +argument list and the initial @samp{@{}. By default, @code{unprotoize} +uses five spaces as the indentation. If you want to indent with just +one space instead, use @option{-i " "}. + +@item -k +Keep the @samp{.X} files. Normally, they are deleted after conversion +is finished. + +@item -l +Add explicit local declarations. @code{protoize} with @option{-l} inserts +a prototype declaration for each function in each block which calls the +function without any declaration. This option applies only to +@code{protoize}. + +@item -n +Make no real changes. This mode just prints information about the conversions +that would have been done without @option{-n}. + +@item -N +Make no @samp{.save} files. The original files are simply deleted. +Use this option with caution. + +@item -p @var{program} +Use the program @var{program} as the compiler. Normally, the name +@file{gcc} is used. + +@item -q +Work quietly. Most warnings are suppressed. + +@item -v +Print the version number, just like @option{-v} for @command{gcc}. +@end table + +If you need special compiler options to compile one of your program's +source files, then you should generate that file's @samp{.X} file +specially, by running @command{gcc} on that source file with the +appropriate options and the option @option{-aux-info}. Then run +@code{protoize} on the entire set of files. @code{protoize} will use +the existing @samp{.X} file because it is newer than the source file. +For example: + +@smallexample +gcc -Dfoo=bar file1.c -aux-info file1.X +protoize *.c +@end smallexample + +@noindent +You need to include the special files along with the rest in the +@code{protoize} command, even though their @samp{.X} files already +exist, because otherwise they won't get converted. + +@xref{Protoize Caveats}, for more information on how to use +@code{protoize} successfully. diff --git a/gcc-4.2.1-5666.3/gcc/doc/languages.texi b/gcc-4.2.1-5666.3/gcc/doc/languages.texi new file mode 100644 index 000000000..514cb08ec --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/languages.texi @@ -0,0 +1,36 @@ +@c Copyright (C) 2002 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Languages +@chapter Language Front Ends in GCC + +The interface to front ends for languages in GCC, and in particular +the @code{tree} structure (@pxref{Trees}), was initially designed for +C, and many aspects of it are still somewhat biased towards C and +C-like languages. It is, however, reasonably well suited to other +procedural languages, and front ends for many such languages have been +written for GCC@. + +Writing a compiler as a front end for GCC, rather than compiling +directly to assembler or generating C code which is then compiled by +GCC, has several advantages: + +@itemize @bullet +@item GCC front ends benefit from the support for many different +target machines already present in GCC@. +@item GCC front ends benefit from all the optimizations in GCC@. Some +of these, such as alias analysis, may work better when GCC is +compiling directly from source code then when it is compiling from +generated C code. +@item Better debugging information is generated when compiling +directly from source code than when going via intermediate generated C +code. +@end itemize + +Because of the advantages of writing a compiler as a GCC front end, +GCC front ends have also been created for languages very different +from those for which GCC was designed, such as the declarative +logic/functional language Mercury. For these reasons, it may also be +useful to implement compilers created for specialized purposes (for +example, as part of a research project) as GCC front ends. diff --git a/gcc-4.2.1-5666.3/gcc/doc/libgcc.texi b/gcc-4.2.1-5666.3/gcc/doc/libgcc.texi new file mode 100644 index 000000000..b7b1cdef0 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/libgcc.texi @@ -0,0 +1,736 @@ +@c Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. +@c Contributed by Aldy Hernandez <aldy@quesejoda.com> + +@node Libgcc +@chapter The GCC low-level runtime library + +GCC provides a low-level runtime library, @file{libgcc.a} or +@file{libgcc_s.so.1} on some platforms. GCC generates calls to +routines in this library automatically, whenever it needs to perform +some operation that is too complicated to emit inline code for. + +Most of the routines in @code{libgcc} handle arithmetic operations +that the target processor cannot perform directly. This includes +integer multiply and divide on some machines, and all floating-point +operations on other machines. @code{libgcc} also includes routines +for exception handling, and a handful of miscellaneous operations. + +Some of these routines can be defined in mostly machine-independent C@. +Others must be hand-written in assembly language for each processor +that needs them. + +GCC will also generate calls to C library routines, such as +@code{memcpy} and @code{memset}, in some cases. The set of routines +that GCC may possibly use is documented in @ref{Other +Builtins,,,gcc, Using the GNU Compiler Collection (GCC)}. + +These routines take arguments and return values of a specific machine +mode, not a specific C type. @xref{Machine Modes}, for an explanation +of this concept. For illustrative purposes, in this chapter the +floating point type @code{float} is assumed to correspond to @code{SFmode}; +@code{double} to @code{DFmode}; and @code{@w{long double}} to both +@code{TFmode} and @code{XFmode}. Similarly, the integer types @code{int} +and @code{@w{unsigned int}} correspond to @code{SImode}; @code{long} and +@code{@w{unsigned long}} to @code{DImode}; and @code{@w{long long}} and +@code{@w{unsigned long long}} to @code{TImode}. + +@menu +* Integer library routines:: +* Soft float library routines:: +* Decimal float library routines:: +* Exception handling routines:: +* Miscellaneous routines:: +@end menu + +@node Integer library routines +@section Routines for integer arithmetic + +The integer arithmetic routines are used on platforms that don't provide +hardware support for arithmetic operations on some modes. + +@subsection Arithmetic functions + +@deftypefn {Runtime Function} int __ashlsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __ashldi3 (long @var{a}, int @var{b}) +@deftypefnx {Runtime Function} {long long} __ashlti3 (long long @var{a}, int @var{b}) +These functions return the result of shifting @var{a} left by @var{b} bits. +@end deftypefn + +@deftypefn {Runtime Function} int __ashrsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __ashrdi3 (long @var{a}, int @var{b}) +@deftypefnx {Runtime Function} {long long} __ashrti3 (long long @var{a}, int @var{b}) +These functions return the result of arithmetically shifting @var{a} right +by @var{b} bits. +@end deftypefn + +@deftypefn {Runtime Function} int __divsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __divdi3 (long @var{a}, long @var{b}) +@deftypefnx {Runtime Function} {long long} __divti3 (long long @var{a}, long long @var{b}) +These functions return the quotient of the signed division of @var{a} and +@var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __lshrsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __lshrdi3 (long @var{a}, int @var{b}) +@deftypefnx {Runtime Function} {long long} __lshrti3 (long long @var{a}, int @var{b}) +These functions return the result of logically shifting @var{a} right by +@var{b} bits. +@end deftypefn + +@deftypefn {Runtime Function} int __modsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __moddi3 (long @var{a}, long @var{b}) +@deftypefnx {Runtime Function} {long long} __modti3 (long long @var{a}, long long @var{b}) +These functions return the remainder of the signed division of @var{a} +and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __mulsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __muldi3 (long @var{a}, long @var{b}) +@deftypefnx {Runtime Function} {long long} __multi3 (long long @var{a}, long long @var{b}) +These functions return the product of @var{a} and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} long __negdi2 (long @var{a}) +@deftypefnx {Runtime Function} {long long} __negti2 (long long @var{a}) +These functions return the negation of @var{a}. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned int} __udivsi3 (unsigned int @var{a}, unsigned int @var{b}) +@deftypefnx {Runtime Function} {unsigned long} __udivdi3 (unsigned long @var{a}, unsigned long @var{b}) +@deftypefnx {Runtime Function} {unsigned long long} __udivti3 (unsigned long long @var{a}, unsigned long long @var{b}) +These functions return the quotient of the unsigned division of @var{a} +and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned long} __udivmoddi3 (unsigned long @var{a}, unsigned long @var{b}, unsigned long *@var{c}) +@deftypefnx {Runtime Function} {unsigned long long} __udivti3 (unsigned long long @var{a}, unsigned long long @var{b}, unsigned long long *@var{c}) +These functions calculate both the quotient and remainder of the unsigned +division of @var{a} and @var{b}. The return value is the quotient, and +the remainder is placed in variable pointed to by @var{c}. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned int} __umodsi3 (unsigned int @var{a}, unsigned int @var{b}) +@deftypefnx {Runtime Function} {unsigned long} __umoddi3 (unsigned long @var{a}, unsigned long @var{b}) +@deftypefnx {Runtime Function} {unsigned long long} __umodti3 (unsigned long long @var{a}, unsigned long long @var{b}) +These functions return the remainder of the unsigned division of @var{a} +and @var{b}. +@end deftypefn + +@subsection Comparison functions + +The following functions implement integral comparisons. These functions +implement a low-level compare, upon which the higher level comparison +operators (such as less than and greater than or equal to) can be +constructed. The returned values lie in the range zero to two, to allow +the high-level operators to be implemented by testing the returned +result using either signed or unsigned comparison. + +@deftypefn {Runtime Function} int __cmpdi2 (long @var{a}, long @var{b}) +@deftypefnx {Runtime Function} int __cmpti2 (long long @var{a}, long long @var{b}) +These functions perform a signed comparison of @var{a} and @var{b}. If +@var{a} is less than @var{b}, they return 0; if @var{a} is greater than +@var{b}, they return 2; and if @var{a} and @var{b} are equal they return 1. +@end deftypefn + +@deftypefn {Runtime Function} int __ucmpdi2 (unsigned long @var{a}, unsigned long @var{b}) +@deftypefnx {Runtime Function} int __ucmpti2 (unsigned long long @var{a}, unsigned long long @var{b}) +These functions perform an unsigned comparison of @var{a} and @var{b}. +If @var{a} is less than @var{b}, they return 0; if @var{a} is greater than +@var{b}, they return 2; and if @var{a} and @var{b} are equal they return 1. +@end deftypefn + +@subsection Trapping arithmetic functions + +The following functions implement trapping arithmetic. These functions +call the libc function @code{abort} upon signed arithmetic overflow. + +@deftypefn {Runtime Function} int __absvsi2 (int @var{a}) +@deftypefnx {Runtime Function} long __absvdi2 (long @var{a}) +These functions return the absolute value of @var{a}. +@end deftypefn + +@deftypefn {Runtime Function} int __addvsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __addvdi3 (long @var{a}, long @var{b}) +These functions return the sum of @var{a} and @var{b}; that is +@code{@var{a} + @var{b}}. +@end deftypefn + +@deftypefn {Runtime Function} int __mulvsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __mulvdi3 (long @var{a}, long @var{b}) +The functions return the product of @var{a} and @var{b}; that is +@code{@var{a} * @var{b}}. +@end deftypefn + +@deftypefn {Runtime Function} int __negvsi2 (int @var{a}) +@deftypefnx {Runtime Function} long __negvdi2 (long @var{a}) +These functions return the negation of @var{a}; that is @code{-@var{a}}. +@end deftypefn + +@deftypefn {Runtime Function} int __subvsi3 (int @var{a}, int @var{b}) +@deftypefnx {Runtime Function} long __subvdi3 (long @var{a}, long @var{b}) +These functions return the difference between @var{b} and @var{a}; +that is @code{@var{a} - @var{b}}. +@end deftypefn + +@subsection Bit operations + +@deftypefn {Runtime Function} int __clzsi2 (int @var{a}) +@deftypefnx {Runtime Function} int __clzdi2 (long @var{a}) +@deftypefnx {Runtime Function} int __clzti2 (long long @var{a}) +These functions return the number of leading 0-bits in @var{a}, starting +at the most significant bit position. If @var{a} is zero, the result is +undefined. +@end deftypefn + +@deftypefn {Runtime Function} int __ctzsi2 (int @var{a}) +@deftypefnx {Runtime Function} int __ctzdi2 (long @var{a}) +@deftypefnx {Runtime Function} int __ctzti2 (long long @var{a}) +These functions return the number of trailing 0-bits in @var{a}, starting +at the least significant bit position. If @var{a} is zero, the result is +undefined. +@end deftypefn + +@deftypefn {Runtime Function} int __ffsdi2 (long @var{a}) +@deftypefnx {Runtime Function} int __ffsti2 (long long @var{a}) +These functions return the index of the least significant 1-bit in @var{a}, +or the value zero if @var{a} is zero. The least significant bit is index +one. +@end deftypefn + +@deftypefn {Runtime Function} int __paritysi2 (int @var{a}) +@deftypefnx {Runtime Function} int __paritydi2 (long @var{a}) +@deftypefnx {Runtime Function} int __parityti2 (long long @var{a}) +These functions return the value zero if the number of bits set in +@var{a} is even, and the value one otherwise. +@end deftypefn + +@deftypefn {Runtime Function} int __popcountsi2 (int @var{a}) +@deftypefnx {Runtime Function} int __popcountdi2 (long @var{a}) +@deftypefnx {Runtime Function} int __popcountti2 (long long @var{a}) +These functions return the number of bits set in @var{a}. +@end deftypefn +@c APPLE LOCAL begin mainline bswap +@deftypefn {Runtime Function} int32_t __bswapsi2 (int32_t @var{a}) +@deftypefnx {Runtime Function} int64_t __bswapdi2 (int64_t @var{a}) +These functions return the @var{a} byteswapped. +@end deftypefn +@c APPLE LOCAL end mainline bswap + +@node Soft float library routines +@section Routines for floating point emulation +@cindex soft float library +@cindex arithmetic library +@cindex math library +@opindex msoft-float + +The software floating point library is used on machines which do not +have hardware support for floating point. It is also used whenever +@option{-msoft-float} is used to disable generation of floating point +instructions. (Not all targets support this switch.) + +For compatibility with other compilers, the floating point emulation +routines can be renamed with the @code{DECLARE_LIBRARY_RENAMES} macro +(@pxref{Library Calls}). In this section, the default names are used. + +Presently the library does not support @code{XFmode}, which is used +for @code{long double} on some architectures. + +@subsection Arithmetic functions + +@deftypefn {Runtime Function} float __addsf3 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} double __adddf3 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} {long double} __addtf3 (long double @var{a}, long double @var{b}) +@deftypefnx {Runtime Function} {long double} __addxf3 (long double @var{a}, long double @var{b}) +These functions return the sum of @var{a} and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} float __subsf3 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} double __subdf3 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} {long double} __subtf3 (long double @var{a}, long double @var{b}) +@deftypefnx {Runtime Function} {long double} __subxf3 (long double @var{a}, long double @var{b}) +These functions return the difference between @var{b} and @var{a}; +that is, @w{@math{@var{a} - @var{b}}}. +@end deftypefn + +@deftypefn {Runtime Function} float __mulsf3 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} double __muldf3 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} {long double} __multf3 (long double @var{a}, long double @var{b}) +@deftypefnx {Runtime Function} {long double} __mulxf3 (long double @var{a}, long double @var{b}) +These functions return the product of @var{a} and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} float __divsf3 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} double __divdf3 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} {long double} __divtf3 (long double @var{a}, long double @var{b}) +@deftypefnx {Runtime Function} {long double} __divxf3 (long double @var{a}, long double @var{b}) +These functions return the quotient of @var{a} and @var{b}; that is, +@w{@math{@var{a} / @var{b}}}. +@end deftypefn + +@deftypefn {Runtime Function} float __negsf2 (float @var{a}) +@deftypefnx {Runtime Function} double __negdf2 (double @var{a}) +@deftypefnx {Runtime Function} {long double} __negtf2 (long double @var{a}) +@deftypefnx {Runtime Function} {long double} __negxf2 (long double @var{a}) +These functions return the negation of @var{a}. They simply flip the +sign bit, so they can produce negative zero and negative NaN@. +@end deftypefn + +@subsection Conversion functions + +@deftypefn {Runtime Function} double __extendsfdf2 (float @var{a}) +@deftypefnx {Runtime Function} {long double} __extendsftf2 (float @var{a}) +@deftypefnx {Runtime Function} {long double} __extendsfxf2 (float @var{a}) +@deftypefnx {Runtime Function} {long double} __extenddftf2 (double @var{a}) +@deftypefnx {Runtime Function} {long double} __extenddfxf2 (double @var{a}) +These functions extend @var{a} to the wider mode of their return +type. +@end deftypefn + +@deftypefn {Runtime Function} double __truncxfdf2 (long double @var{a}) +@deftypefnx {Runtime Function} double __trunctfdf2 (long double @var{a}) +@deftypefnx {Runtime Function} float __truncxfsf2 (long double @var{a}) +@deftypefnx {Runtime Function} float __trunctfsf2 (long double @var{a}) +@deftypefnx {Runtime Function} float __truncdfsf2 (double @var{a}) +These functions truncate @var{a} to the narrower mode of their return +type, rounding toward zero. +@end deftypefn + +@deftypefn {Runtime Function} int __fixsfsi (float @var{a}) +@deftypefnx {Runtime Function} int __fixdfsi (double @var{a}) +@deftypefnx {Runtime Function} int __fixtfsi (long double @var{a}) +@deftypefnx {Runtime Function} int __fixxfsi (long double @var{a}) +These functions convert @var{a} to a signed integer, rounding toward zero. +@end deftypefn + +@deftypefn {Runtime Function} long __fixsfdi (float @var{a}) +@deftypefnx {Runtime Function} long __fixdfdi (double @var{a}) +@deftypefnx {Runtime Function} long __fixtfdi (long double @var{a}) +@deftypefnx {Runtime Function} long __fixxfdi (long double @var{a}) +These functions convert @var{a} to a signed long, rounding toward zero. +@end deftypefn + +@deftypefn {Runtime Function} {long long} __fixsfti (float @var{a}) +@deftypefnx {Runtime Function} {long long} __fixdfti (double @var{a}) +@deftypefnx {Runtime Function} {long long} __fixtfti (long double @var{a}) +@deftypefnx {Runtime Function} {long long} __fixxfti (long double @var{a}) +These functions convert @var{a} to a signed long long, rounding toward zero. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned int} __fixunssfsi (float @var{a}) +@deftypefnx {Runtime Function} {unsigned int} __fixunsdfsi (double @var{a}) +@deftypefnx {Runtime Function} {unsigned int} __fixunstfsi (long double @var{a}) +@deftypefnx {Runtime Function} {unsigned int} __fixunsxfsi (long double @var{a}) +These functions convert @var{a} to an unsigned integer, rounding +toward zero. Negative values all become zero. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned long} __fixunssfdi (float @var{a}) +@deftypefnx {Runtime Function} {unsigned long} __fixunsdfdi (double @var{a}) +@deftypefnx {Runtime Function} {unsigned long} __fixunstfdi (long double @var{a}) +@deftypefnx {Runtime Function} {unsigned long} __fixunsxfdi (long double @var{a}) +These functions convert @var{a} to an unsigned long, rounding +toward zero. Negative values all become zero. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned long long} __fixunssfti (float @var{a}) +@deftypefnx {Runtime Function} {unsigned long long} __fixunsdfti (double @var{a}) +@deftypefnx {Runtime Function} {unsigned long long} __fixunstfti (long double @var{a}) +@deftypefnx {Runtime Function} {unsigned long long} __fixunsxfti (long double @var{a}) +These functions convert @var{a} to an unsigned long long, rounding +toward zero. Negative values all become zero. +@end deftypefn + +@deftypefn {Runtime Function} float __floatsisf (int @var{i}) +@deftypefnx {Runtime Function} double __floatsidf (int @var{i}) +@deftypefnx {Runtime Function} {long double} __floatsitf (int @var{i}) +@deftypefnx {Runtime Function} {long double} __floatsixf (int @var{i}) +These functions convert @var{i}, a signed integer, to floating point. +@end deftypefn + +@deftypefn {Runtime Function} float __floatdisf (long @var{i}) +@deftypefnx {Runtime Function} double __floatdidf (long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatditf (long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatdixf (long @var{i}) +These functions convert @var{i}, a signed long, to floating point. +@end deftypefn + +@deftypefn {Runtime Function} float __floattisf (long long @var{i}) +@deftypefnx {Runtime Function} double __floattidf (long long @var{i}) +@deftypefnx {Runtime Function} {long double} __floattitf (long long @var{i}) +@deftypefnx {Runtime Function} {long double} __floattixf (long long @var{i}) +These functions convert @var{i}, a signed long long, to floating point. +@end deftypefn + +@deftypefn {Runtime Function} float __floatunsisf (unsigned int @var{i}) +@deftypefnx {Runtime Function} double __floatunsidf (unsigned int @var{i}) +@deftypefnx {Runtime Function} {long double} __floatunsitf (unsigned int @var{i}) +@deftypefnx {Runtime Function} {long double} __floatunsixf (unsigned int @var{i}) +These functions convert @var{i}, an unsigned integer, to floating point. +@end deftypefn + +@deftypefn {Runtime Function} float __floatundisf (unsigned long @var{i}) +@deftypefnx {Runtime Function} double __floatundidf (unsigned long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatunditf (unsigned long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatundixf (unsigned long @var{i}) +These functions convert @var{i}, an unsigned long, to floating point. +@end deftypefn + +@deftypefn {Runtime Function} float __floatuntisf (unsigned long long @var{i}) +@deftypefnx {Runtime Function} double __floatuntidf (unsigned long long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatuntitf (unsigned long long @var{i}) +@deftypefnx {Runtime Function} {long double} __floatuntixf (unsigned long long @var{i}) +These functions convert @var{i}, an unsigned long long, to floating point. +@end deftypefn + +@subsection Comparison functions + +There are two sets of basic comparison functions. + +@deftypefn {Runtime Function} int __cmpsf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __cmpdf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __cmptf2 (long double @var{a}, long double @var{b}) +These functions calculate @math{a <=> b}. That is, if @var{a} is less +than @var{b}, they return @minus{}1; if @var{a} is greater than @var{b}, they +return 1; and if @var{a} and @var{b} are equal they return 0. If +either argument is NaN they return 1, but you should not rely on this; +if NaN is a possibility, use one of the higher-level comparison +functions. +@end deftypefn + +@deftypefn {Runtime Function} int __unordsf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __unorddf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __unordtf2 (long double @var{a}, long double @var{b}) +These functions return a nonzero value if either argument is NaN, otherwise 0. +@end deftypefn + +There is also a complete group of higher level functions which +correspond directly to comparison operators. They implement the ISO C +semantics for floating-point comparisons, taking NaN into account. +Pay careful attention to the return values defined for each set. +Under the hood, all of these routines are implemented as + +@smallexample + if (__unord@var{X}f2 (a, b)) + return @var{E}; + return __cmp@var{X}f2 (a, b); +@end smallexample + +@noindent +where @var{E} is a constant chosen to give the proper behavior for +NaN@. Thus, the meaning of the return value is different for each set. +Do not rely on this implementation; only the semantics documented +below are guaranteed. + +@deftypefn {Runtime Function} int __eqsf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __eqdf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __eqtf2 (long double @var{a}, long double @var{b}) +These functions return zero if neither argument is NaN, and @var{a} and +@var{b} are equal. +@end deftypefn + +@deftypefn {Runtime Function} int __nesf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __nedf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __netf2 (long double @var{a}, long double @var{b}) +These functions return a nonzero value if either argument is NaN, or +if @var{a} and @var{b} are unequal. +@end deftypefn + +@deftypefn {Runtime Function} int __gesf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __gedf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __getf2 (long double @var{a}, long double @var{b}) +These functions return a value greater than or equal to zero if +neither argument is NaN, and @var{a} is greater than or equal to +@var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __ltsf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __ltdf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __lttf2 (long double @var{a}, long double @var{b}) +These functions return a value less than zero if neither argument is +NaN, and @var{a} is strictly less than @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __lesf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __ledf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __letf2 (long double @var{a}, long double @var{b}) +These functions return a value less than or equal to zero if neither +argument is NaN, and @var{a} is less than or equal to @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __gtsf2 (float @var{a}, float @var{b}) +@deftypefnx {Runtime Function} int __gtdf2 (double @var{a}, double @var{b}) +@deftypefnx {Runtime Function} int __gttf2 (long double @var{a}, long double @var{b}) +These functions return a value greater than zero if neither argument +is NaN, and @var{a} is strictly greater than @var{b}. +@end deftypefn + +@subsection Other floating-point functions + +@deftypefn {Runtime Function} float __powisf2 (float @var{a}, int @var{b}) +@deftypefnx {Runtime Function} double __powidf2 (double @var{a}, int @var{b}) +@deftypefnx {Runtime Function} {long double} __powitf2 (long double @var{a}, int @var{b}) +@deftypefnx {Runtime Function} {long double} __powixf2 (long double @var{a}, int @var{b}) +These functions convert raise @var{a} to the power @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} {complex float} __mulsc3 (float @var{a}, float @var{b}, float @var{c}, float @var{d}) +@deftypefnx {Runtime Function} {complex double} __muldc3 (double @var{a}, double @var{b}, double @var{c}, double @var{d}) +@deftypefnx {Runtime Function} {complex long double} __multc3 (long double @var{a}, long double @var{b}, long double @var{c}, long double @var{d}) +@deftypefnx {Runtime Function} {complex long double} __mulxc3 (long double @var{a}, long double @var{b}, long double @var{c}, long double @var{d}) +These functions return the product of @math{@var{a} + i@var{b}} and +@math{@var{c} + i@var{d}}, following the rules of C99 Annex G@. +@end deftypefn + +@deftypefn {Runtime Function} {complex float} __divsc3 (float @var{a}, float @var{b}, float @var{c}, float @var{d}) +@deftypefnx {Runtime Function} {complex double} __divdc3 (double @var{a}, double @var{b}, double @var{c}, double @var{d}) +@deftypefnx {Runtime Function} {complex long double} __divtc3 (long double @var{a}, long double @var{b}, long double @var{c}, long double @var{d}) +@deftypefnx {Runtime Function} {complex long double} __divxc3 (long double @var{a}, long double @var{b}, long double @var{c}, long double @var{d}) +These functions return the quotient of @math{@var{a} + i@var{b}} and +@math{@var{c} + i@var{d}} (i.e., @math{(@var{a} + i@var{b}) / (@var{c} ++ i@var{d})}), following the rules of C99 Annex G@. +@end deftypefn + +@node Decimal float library routines +@section Routines for decimal floating point emulation +@cindex decimal float library +@cindex IEEE-754R + +The software decimal floating point library implements IEEE 754R +decimal floating point arithmetic and is only activated on selected +targets. + +@subsection Arithmetic functions + +@deftypefn {Runtime Function} _Decimal32 __addsd3 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} _Decimal64 __adddd3 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} _Decimal128 __addtd3 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return the sum of @var{a} and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __subsd3 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} _Decimal64 __subdd3 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} _Decimal128 __subtd3 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return the difference between @var{b} and @var{a}; +that is, @w{@math{@var{a} - @var{b}}}. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __mulsd3 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} _Decimal64 __muldd3 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} _Decimal128 __multd3 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return the product of @var{a} and @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __divsd3 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} _Decimal64 __divdd3 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} _Decimal128 __divtd3 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return the quotient of @var{a} and @var{b}; that is, +@w{@math{@var{a} / @var{b}}}. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __negsd2 (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} _Decimal64 __negdd2 (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __negtd2 (_Decimal128 @var{a}) +These functions return the negation of @var{a}. They simply flip the +sign bit, so they can produce negative zero and negative NaN@. +@end deftypefn + +@subsection Conversion functions + +@c DFP/DFP conversions +@deftypefn {Runtime Function} _Decimal64 __extendsddd2 (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __extendsdtd2 (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __extendddtd2 (_Decimal64 @var{a}) +@c DFP/binary FP conversions +@deftypefnx {Runtime Function} _Decimal32 __extendsfsd (float @var{a}) +@deftypefnx {Runtime Function} double __extendsddf (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} {long double} __extendsdxf (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} _Decimal64 __extendsfdd (float @var{a}) +@deftypefnx {Runtime Function} _Decimal64 __extenddfdd (double @var{a}) +@deftypefnx {Runtime Function} {long double} __extendddxf (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __extendsftd (float @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __extenddftd (double @var{a}) +@deftypefnx {Runtime Function} _Decimal128 __extendxftd ({long double} @var{a}) +These functions extend @var{a} to the wider mode of their return type. +@end deftypefn + +@c DFP/DFP conversions +@deftypefn {Runtime Function} _Decimal32 __truncddsd2 (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} _Decimal32 __trunctdsd2 (_Decimal128 @var{a}) +@deftypefnx {Runtime Function} _Decimal64 __trunctddd2 (_Decimal128 @var{a}) +@c DFP/binary FP conversions +@deftypefnx {Runtime Function} float __truncsdsf (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} _Decimal32 __truncdfsd (double @var{a}) +@deftypefnx {Runtime Function} _Decimal32 __truncxfsd ({long double} @var{a}) +@deftypefnx {Runtime Function} float __truncddsf (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} double __truncdddf (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} _Decimal64 __truncxfdd ({long double} @var{a}) +@deftypefnx {Runtime Function} float __trunctdsf (_Decimal128 @var{a}) +@deftypefnx {Runtime Function} double __trunctddf (_Decimal128 @var{a}) +@deftypefnx {Runtime Function} {long double} __trunctdxf (_Decimal128 @var{a}) +These functions truncate @var{a} to the narrower mode of their return +type. +@end deftypefn + +@deftypefn {Runtime Function} int __fixsdsi (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} int __fixddsi (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} int __fixtdsi (_Decimal128 @var{a}) +These functions convert @var{a} to a signed integer. +@end deftypefn + +@deftypefn {Runtime Function} long __fixsddi (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} long __fixdddi (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} long __fixtddi (_Decimal128 @var{a}) +These functions convert @var{a} to a signed long. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned int} __fixunssdsi (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} {unsigned int} __fixunsddsi (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} {unsigned int} __fixunstdsi (_Decimal128 @var{a}) +These functions convert @var{a} to an unsigned integer. Negative values all become zero. +@end deftypefn + +@deftypefn {Runtime Function} {unsigned long} __fixunssddi (_Decimal32 @var{a}) +@deftypefnx {Runtime Function} {unsigned long} __fixunsdddi (_Decimal64 @var{a}) +@deftypefnx {Runtime Function} {unsigned long} __fixunstddi (_Decimal128 @var{a}) +These functions convert @var{a} to an unsigned long. Negative values +all become zero. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __floatsisd (int @var{i}) +@deftypefnx {Runtime Function} _Decimal64 __floatsidd (int @var{i}) +@deftypefnx {Runtime Function} _Decimal128 __floatsitd (int @var{i}) +These functions convert @var{i}, a signed integer, to decimal floating point. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __floatdisd (long @var{i}) +@deftypefnx {Runtime Function} _Decimal64 __floatdidd (long @var{i}) +@deftypefnx {Runtime Function} _Decimal128 __floatditd (long @var{i}) +These functions convert @var{i}, a signed long, to decimal floating point. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __floatunssisd (unsigned int @var{i}) +@deftypefnx {Runtime Function} _Decimal64 __floatunssidd (unsigned int @var{i}) +@deftypefnx {Runtime Function} _Decimal128 __floatunssitd (unsigned int @var{i}) +These functions convert @var{i}, an unsigned integer, to decimal floating point. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __floatunsdisd (unsigned long @var{i}) +@deftypefnx {Runtime Function} _Decimal64 __floatunsdidd (unsigned long @var{i}) +@deftypefnx {Runtime Function} _Decimal128 __floatunsditd (unsigned long @var{i}) +These functions convert @var{i}, an unsigned long, to decimal floating point. +@end deftypefn + +@subsection Comparison functions + +@deftypefn {Runtime Function} int __unordsd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __unorddd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __unordtd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a nonzero value if either argument is NaN, otherwise 0. +@end deftypefn + +There is also a complete group of higher level functions which +correspond directly to comparison operators. They implement the ISO C +semantics for floating-point comparisons, taking NaN into account. +Pay careful attention to the return values defined for each set. +Under the hood, all of these routines are implemented as + +@smallexample + if (__unord@var{X}d2 (a, b)) + return @var{E}; + return __cmp@var{X}d2 (a, b); +@end smallexample + +@noindent +where @var{E} is a constant chosen to give the proper behavior for +NaN@. Thus, the meaning of the return value is different for each set. +Do not rely on this implementation; only the semantics documented +below are guaranteed. + +@deftypefn {Runtime Function} int __eqsd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __eqdd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __eqtd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return zero if neither argument is NaN, and @var{a} and +@var{b} are equal. +@end deftypefn + +@deftypefn {Runtime Function} int __nesd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __nedd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __netd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a nonzero value if either argument is NaN, or +if @var{a} and @var{b} are unequal. +@end deftypefn + +@deftypefn {Runtime Function} int __gesd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __gedd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __getd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a value greater than or equal to zero if +neither argument is NaN, and @var{a} is greater than or equal to +@var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __ltsd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __ltdd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __lttd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a value less than zero if neither argument is +NaN, and @var{a} is strictly less than @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __lesd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __ledd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __letd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a value less than or equal to zero if neither +argument is NaN, and @var{a} is less than or equal to @var{b}. +@end deftypefn + +@deftypefn {Runtime Function} int __gtsd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) +@deftypefnx {Runtime Function} int __gtdd2 (_Decimal64 @var{a}, _Decimal64 @var{b}) +@deftypefnx {Runtime Function} int __gttd2 (_Decimal128 @var{a}, _Decimal128 @var{b}) +These functions return a value greater than zero if neither argument +is NaN, and @var{a} is strictly greater than @var{b}. +@end deftypefn + +@node Exception handling routines +@section Language-independent routines for exception handling + +document me! + +@smallexample + _Unwind_DeleteException + _Unwind_Find_FDE + _Unwind_ForcedUnwind + _Unwind_GetGR + _Unwind_GetIP + _Unwind_GetLanguageSpecificData + _Unwind_GetRegionStart + _Unwind_GetTextRelBase + _Unwind_GetDataRelBase + _Unwind_RaiseException + _Unwind_Resume + _Unwind_SetGR + _Unwind_SetIP + _Unwind_FindEnclosingFunction + _Unwind_SjLj_Register + _Unwind_SjLj_Unregister + _Unwind_SjLj_RaiseException + _Unwind_SjLj_ForcedUnwind + _Unwind_SjLj_Resume + __deregister_frame + __deregister_frame_info + __deregister_frame_info_bases + __register_frame + __register_frame_info + __register_frame_info_bases + __register_frame_info_table + __register_frame_info_table_bases + __register_frame_table +@end smallexample + +@node Miscellaneous routines +@section Miscellaneous runtime library routines + +@subsection Cache control functions +@deftypefn {Runtime Function} void __clear_cache (char *@var{beg}, char *@var{end}) +This function clears the instruction cache between @var{beg} and @var{end}. +@end deftypefn diff --git a/gcc-4.2.1-5666.3/gcc/doc/loop.texi b/gcc-4.2.1-5666.3/gcc/doc/loop.texi new file mode 100644 index 000000000..5e2db5841 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/loop.texi @@ -0,0 +1,604 @@ +@c Copyright (c) 2006 Free Software Foundation, Inc. +@c Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Loop Representation +@c --------------------------------------------------------------------- + +@node Loop Analysis and Representation +@chapter Analysis and Representation of Loops + +GCC provides extensive infrastructure for work with natural loops, i.e., +strongly connected components of CFG with only one entry block. This +chapter describes representation of loops in GCC, both on GIMPLE and in +RTL, as well as the interfaces to loop-related analyses (induction +variable analysis and number of iterations analysis). + +@menu +* Loop representation:: Representation and analysis of loops. +* Loop querying:: Getting information about loops. +* Loop manipulation:: Loop manipulation functions. +* LCSSA:: Loop-closed SSA form. +* Scalar evolutions:: Induction variables on GIMPLE. +* loop-iv:: Induction variables on RTL. +* Number of iterations:: Number of iterations analysis. +* Dependency analysis:: Data dependency analysis. +* Lambda:: Linear loop transformations framework. +@end menu + +@node Loop representation +@section Loop representation +@cindex Loop representation +@cindex Loop analysis + +This chapter describes the representation of loops in GCC, and functions +that can be used to build, modify and analyze this representation. Most +of the interfaces and data structures are declared in @file{cfgloop.h}. +At the moment, loop structures are analyzed and this information is +updated only by the optimization passes that deal with loops, but some +efforts are being made to make it available throughout most of the +optimization passes. + +In general, a natural loop has one entry block (header) and possibly +several back edges (latches) leading to the header from the inside of +the loop. Loops with several latches may appear if several loops share +a single header, or if there is a branching in the middle of the loop. +The representation of loops in GCC however allows only loops with a +single latch. During loop analysis, headers of such loops are split and +forwarder blocks are created in order to disambiguate their structures. +A heuristic based on profile information is used to determine whether +the latches correspond to sub-loops or to control flow in a single loop. +This means that the analysis sometimes changes the CFG, and if you run +it in the middle of an optimization pass, you must be able to deal with +the new blocks. + +Body of the loop is the set of blocks that are dominated by its header, +and reachable from its latch against the direction of edges in CFG. The +loops are organized in a containment hierarchy (tree) such that all the +loops immediately contained inside loop L are the children of L in the +tree. This tree is represented by the @code{struct loops} structure. +The root of this tree is a fake loop that contains all blocks in the +function. Each of the loops is represented in a @code{struct loop} +structure. Each loop is assigned an index (@code{num} field of the +@code{struct loop} structure), and the pointer to the loop is stored in +the corresponding field of the @code{parray} field of the loops +structure. Index of a sub-loop is always greater than the index of its +super-loop. The indices do not have to be continuous, there may be +empty (@code{NULL}) entries in the @code{parray} created by deleting +loops. The index of a loop never changes. The first unused index is +stored in the @code{num} field of the loops structure. + +Each basic block contains the reference to the innermost loop it belongs +to (@code{loop_father}). For this reason, it is only possible to have +one @code{struct loops} structure initialized at the same time for each +CFG. It is recommended to use the global variable @code{current_loops} +to contain the @code{struct loops} structure, especially if the loop +structures are updated throughout several passes. Many of the loop +manipulation functions assume that dominance information is up-to-date. + +The loops are analyzed through @code{loop_optimizer_init} function. The +argument of this function is a set of flags represented in an integer +bitmask. These flags specify what other properties of the loop +structures should be calculated/enforced and preserved later: + +@itemize +@item @code{LOOPS_HAVE_PREHEADERS}: Forwarder blocks are created in such +a way that each loop has only one entry edge, and additionally, the +source block of this entry edge has only one successor. This creates a +natural place where the code can be moved out of the loop, and ensures +that the entry edge of the loop leads from its immediate super-loop. +@item @code{LOOPS_HAVE_SIMPLE_LATCHES}: Forwarder blocks are created to +force the latch block of each loop to have only one successor. This +ensures that the latch of the loop does not belong to any of its +sub-loops, and makes manipulation with the loops significantly easier. +Most of the loop manipulation functions assume that the loops are in +this shape. Note that with this flag, the ``normal'' loop without any +control flow inside and with one exit consists of two basic blocks. +@item @code{LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS}: Basic blocks and +edges in the strongly connected components that are not natural loops +(have more than one entry block) are marked with +@code{BB_IRREDUCIBLE_LOOP} and @code{EDGE_IRREDUCIBLE_LOOP} flags. The +flag is not set for blocks and edges that belong to natural loops that +are in such an irreducible region (but it is set for the entry and exit +edges of such a loop, if they lead to/from this region). +@item @code{LOOPS_HAVE_MARKED_SINGLE_EXITS}: If a loop has exactly one +exit edge, this edge is stored in @code{single_exit} field of the loop +structure. @code{NULL} is stored there otherwise. +@end itemize + +These properties may also be computed/enforced later, using functions +@code{create_preheaders}, @code{force_single_succ_latches}, +@code{mark_irreducible_loops} and @code{mark_single_exit_loops}. + +The memory occupied by the loops structures should be freed with +@code{loop_optimizer_finalize} function. + +The CFG manipulation functions in general do not update loop structures. +Specialized versions that additionally do so are provided for the most +common tasks. On GIMPLE, @code{cleanup_tree_cfg_loop} function can be +used to cleanup CFG while updating the loops structures if +@code{current_loops} is set. + +@node Loop querying +@section Loop querying +@cindex Loop querying + +The functions to query the information about loops are declared in +@file{cfgloop.h}. Some of the information can be taken directly from +the structures. @code{loop_father} field of each basic block contains +the innermost loop to that the block belongs. The most useful fields of +loop structure (that are kept up-to-date at all times) are: + +@itemize +@item @code{header}, @code{latch}: Header and latch basic blocks of the +loop. +@item @code{num_nodes}: Number of basic blocks in the loop (including +the basic blocks of the sub-loops). +@item @code{depth}: The depth of the loop in the loops tree, i.e., the +number of super-loops of the loop. +@item @code{outer}, @code{inner}, @code{next}: The super-loop, the first +sub-loop, and the sibling of the loop in the loops tree. +@item @code{single_exit}: The exit edge of the loop, if the loop has +exactly one exit and the loops were analyzed with +LOOPS_HAVE_MARKED_SINGLE_EXITS. +@end itemize + +There are other fields in the loop structures, many of them used only by +some of the passes, or not updated during CFG changes; in general, they +should not be accessed directly. + +The most important functions to query loop structures are: + +@itemize +@item @code{flow_loops_dump}: Dumps the information about loops to a +file. +@item @code{verify_loop_structure}: Checks consistency of the loop +structures. +@item @code{loop_latch_edge}: Returns the latch edge of a loop. +@item @code{loop_preheader_edge}: If loops have preheaders, returns +the preheader edge of a loop. +@item @code{flow_loop_nested_p}: Tests whether loop is a sub-loop of +another loop. +@item @code{flow_bb_inside_loop_p}: Tests whether a basic block belongs +to a loop (including its sub-loops). +@item @code{find_common_loop}: Finds the common super-loop of two loops. +@item @code{superloop_at_depth}: Returns the super-loop of a loop with +the given depth. +@item @code{tree_num_loop_insns}, @code{num_loop_insns}: Estimates the +number of insns in the loop, on GIMPLE and on RTL. +@item @code{loop_exit_edge_p}: Tests whether edge is an exit from a +loop. +@item @code{mark_loop_exit_edges}: Marks all exit edges of all loops +with @code{EDGE_LOOP_EXIT} flag. +@item @code{get_loop_body}, @code{get_loop_body_in_dom_order}, +@code{get_loop_body_in_bfs_order}: Enumerates the basic blocks in the +loop in depth-first search order in reversed CFG, ordered by dominance +relation, and breath-first search order, respectively. +@item @code{get_loop_exit_edges}: Enumerates the exit edges of a loop. +@item @code{just_once_each_iteration_p}: Returns true if the basic block +is executed exactly once during each iteration of a loop (that is, it +does not belong to a sub-loop, and it dominates the latch of the loop). +@end itemize + +@node Loop manipulation +@section Loop manipulation +@cindex Loop manipulation + +The loops tree can be manipulated using the following functions: + +@itemize +@item @code{flow_loop_tree_node_add}: Adds a node to the tree. +@item @code{flow_loop_tree_node_remove}: Removes a node from the tree. +@item @code{add_bb_to_loop}: Adds a basic block to a loop. +@item @code{remove_bb_from_loops}: Removes a basic block from loops. +@end itemize + +The specialized versions of several low-level CFG functions that also +update loop structures are provided: + +@itemize +@item @code{loop_split_edge_with}: Splits an edge, and places a +specified RTL code on it. On GIMPLE, the function can still be used, +but the code must be NULL. +@item @code{bsi_insert_on_edge_immediate_loop}: Inserts code on edge, +splitting it if necessary. Only works on GIMPLE. +@item @code{remove_path}: Removes an edge and all blocks it dominates. +@item @code{loop_commit_inserts}: Commits insertions scheduled on edges, +and sets loops for the new blocks. This function can only be used on +GIMPLE. +@item @code{split_loop_exit_edge}: Splits exit edge of the loop, +ensuring that PHI node arguments remain in the loop (this ensures that +loop-closed SSA form is preserved). Only useful on GIMPLE. +@end itemize + +Finally, there are some higher-level loop transformations implemented. +While some of them are written so that they should work on non-innermost +loops, they are mostly untested in that case, and at the moment, they +are only reliable for the innermost loops: + +@itemize +@item @code{create_iv}: Creates a new induction variable. Only works on +GIMPLE. @code{standard_iv_increment_position} can be used to find a +suitable place for the iv increment. +@item @code{duplicate_loop_to_header_edge}, +@code{tree_duplicate_loop_to_header_edge}: These functions (on RTL and +on GIMPLE) duplicate the body of the loop prescribed number of times on +one of the edges entering loop header, thus performing either loop +unrolling or loop peeling. @code{can_duplicate_loop_p} +(@code{can_unroll_loop_p} on GIMPLE) must be true for the duplicated +loop. +@item @code{loop_version}, @code{tree_ssa_loop_version}: These function +create a copy of a loop, and a branch before them that selects one of +them depending on the prescribed condition. This is useful for +optimizations that need to verify some assumptions in runtime (one of +the copies of the loop is usually left unchanged, while the other one is +transformed in some way). +@item @code{tree_unroll_loop}: Unrolls the loop, including peeling the +extra iterations to make the number of iterations divisible by unroll +factor, updating the exit condition, and removing the exits that now +cannot be taken. Works only on GIMPLE. +@end itemize + +@node LCSSA +@section Loop-closed SSA form +@cindex LCSSA +@cindex Loop-closed SSA form + +Throughout the loop optimizations on tree level, one extra condition is +enforced on the SSA form: No SSA name is used outside of the loop in +that it is defined. The SSA form satisfying this condition is called +``loop-closed SSA form'' -- LCSSA. To enforce LCSSA, PHI nodes must be +created at the exits of the loops for the SSA names that are used +outside of them. Only the real operands (not virtual SSA names) are +held in LCSSA, in order to save memory. + +There are various benefits of LCSSA: + +@itemize +@item Many optimizations (value range analysis, final value +replacement) are interested in the values that are defined in the loop +and used outside of it, i.e., exactly those for that we create new PHI +nodes. +@item In induction variable analysis, it is not necessary to specify the +loop in that the analysis should be performed -- the scalar evolution +analysis always returns the results with respect to the loop in that the +SSA name is defined. +@item It makes updating of SSA form during loop transformations simpler. +Without LCSSA, operations like loop unrolling may force creation of PHI +nodes arbitrarily far from the loop, while in LCSSA, the SSA form can be +updated locally. However, since we only keep real operands in LCSSA, we +cannot use this advantage (we could have local updating of real +operands, but it is not much more efficient than to use generic SSA form +updating for it as well; the amount of changes to SSA is the same). +@end itemize + +However, it also means LCSSA must be updated. This is usually +straightforward, unless you create a new value in loop and use it +outside, or unless you manipulate loop exit edges (functions are +provided to make these manipulations simple). +@code{rewrite_into_loop_closed_ssa} is used to rewrite SSA form to +LCSSA, and @code{verify_loop_closed_ssa} to check that the invariant of +LCSSA is preserved. + +@node Scalar evolutions +@section Scalar evolutions +@cindex Scalar evolutions +@cindex IV analysis on GIMPLE + +Scalar evolutions (SCEV) are used to represent results of induction +variable analysis on GIMPLE. They enable us to represent variables with +complicated behavior in a simple and consistent way (we only use it to +express values of polynomial induction variables, but it is possible to +extend it). The interfaces to SCEV analysis are declared in +@file{tree-scalar-evolution.h}. To use scalar evolutions analysis, +@code{scev_initialize} must be used. To stop using SCEV, +@code{scev_finalize} should be used. SCEV analysis caches results in +order to save time and memory. This cache however is made invalid by +most of the loop transformations, including removal of code. If such a +transformation is performed, @code{scev_reset} must be called to clean +the caches. + +Given an SSA name, its behavior in loops can be analyzed using the +@code{analyze_scalar_evolution} function. The returned SCEV however +does not have to be fully analyzed and it may contain references to +other SSA names defined in the loop. To resolve these (potentially +recursive) references, @code{instantiate_parameters} or +@code{resolve_mixers} functions must be used. +@code{instantiate_parameters} is useful when you use the results of SCEV +only for some analysis, and when you work with whole nest of loops at +once. It will try replacing all SSA names by their SCEV in all loops, +including the super-loops of the current loop, thus providing a complete +information about the behavior of the variable in the loop nest. +@code{resolve_mixers} is useful if you work with only one loop at a +time, and if you possibly need to create code based on the value of the +induction variable. It will only resolve the SSA names defined in the +current loop, leaving the SSA names defined outside unchanged, even if +their evolution in the outer loops is known. + +The SCEV is a normal tree expression, except for the fact that it may +contain several special tree nodes. One of them is +@code{SCEV_NOT_KNOWN}, used for SSA names whose value cannot be +expressed. The other one is @code{POLYNOMIAL_CHREC}. Polynomial chrec +has three arguments -- base, step and loop (both base and step may +contain further polynomial chrecs). Type of the expression and of base +and step must be the same. A variable has evolution +@code{POLYNOMIAL_CHREC(base, step, loop)} if it is (in the specified +loop) equivalent to @code{x_1} in the following example + +@smallexample +while (...) + @{ + x_1 = phi (base, x_2); + x_2 = x_1 + step; + @} +@end smallexample + +Note that this includes the language restrictions on the operations. +For example, if we compile C code and @code{x} has signed type, then the +overflow in addition would cause undefined behavior, and we may assume +that this does not happen. Hence, the value with this SCEV cannot +overflow (which restricts the number of iterations of such a loop). + +In many cases, one wants to restrict the attention just to affine +induction variables. In this case, the extra expressive power of SCEV +is not useful, and may complicate the optimizations. In this case, +@code{simple_iv} function may be used to analyze a value -- the result +is a loop-invariant base and step. + +@node loop-iv +@section IV analysis on RTL +@cindex IV analysis on RTL + +The induction variable on RTL is simple and only allows analysis of +affine induction variables, and only in one loop at once. The interface +is declared in @file{cfgloop.h}. Before analyzing induction variables +in a loop L, @code{iv_analysis_loop_init} function must be called on L. +After the analysis (possibly calling @code{iv_analysis_loop_init} for +several loops) is finished, @code{iv_analysis_done} should be called. +The following functions can be used to access the results of the +analysis: + +@itemize +@item @code{iv_analyze}: Analyzes a single register used in the given +insn. If no use of the register in this insn is found, the following +insns are scanned, so that this function can be called on the insn +returned by get_condition. +@item @code{iv_analyze_result}: Analyzes result of the assignment in the +given insn. +@item @code{iv_analyze_expr}: Analyzes a more complicated expression. +All its operands are analyzed by @code{iv_analyze}, and hence they must +be used in the specified insn or one of the following insns. +@end itemize + +The description of the induction variable is provided in @code{struct +rtx_iv}. In order to handle subregs, the representation is a bit +complicated; if the value of the @code{extend} field is not +@code{UNKNOWN}, the value of the induction variable in the i-th +iteration is + +@smallexample +delta + mult * extend_@{extend_mode@} (subreg_@{mode@} (base + i * step)), +@end smallexample + +with the following exception: if @code{first_special} is true, then the +value in the first iteration (when @code{i} is zero) is @code{delta + +mult * base}. However, if @code{extend} is equal to @code{UNKNOWN}, +then @code{first_special} must be false, @code{delta} 0, @code{mult} 1 +and the value in the i-th iteration is + +@smallexample +subreg_@{mode@} (base + i * step) +@end smallexample + +The function @code{get_iv_value} can be used to perform these +calculations. + +@node Number of iterations +@section Number of iterations analysis +@cindex Number of iterations analysis + +Both on GIMPLE and on RTL, there are functions available to determine +the number of iterations of a loop, with a similar interface. In many +cases, it is not possible to determine number of iterations +unconditionally -- the determined number is correct only if some +assumptions are satisfied. The analysis tries to verify these +conditions using the information contained in the program; if it fails, +the conditions are returned together with the result. The following +information and conditions are provided by the analysis: + +@itemize +@item @code{assumptions}: If this condition is false, the rest of +the information is invalid. +@item @code{noloop_assumptions} on RTL, @code{may_be_zero} on GIMPLE: If +this condition is true, the loop exits in the first iteration. +@item @code{infinite}: If this condition is true, the loop is infinite. +This condition is only available on RTL. On GIMPLE, conditions for +finiteness of the loop are included in @code{assumptions}. +@item @code{niter_expr} on RTL, @code{niter} on GIMPLE: The expression +that gives number of iterations. The number of iterations is defined as +the number of executions of the loop latch. +@end itemize + +Both on GIMPLE and on RTL, it necessary for the induction variable +analysis framework to be initialized (SCEV on GIMPLE, loop-iv on RTL). +On GIMPLE, the results are stored to @code{struct tree_niter_desc} +structure. Number of iterations before the loop is exited through a +given exit can be determined using @code{number_of_iterations_exit} +function. On RTL, the results are returned in @code{struct niter_desc} +structure. The corresponding function is named +@code{check_simple_exit}. There are also functions that pass through +all the exits of a loop and try to find one with easy to determine +number of iterations -- @code{find_loop_niter} on GIMPLE and +@code{find_simple_exit} on RTL. Finally, there are functions that +provide the same information, but additionally cache it, so that +repeated calls to number of iterations are not so costly -- +@code{number_of_iterations_in_loop} on GIMPLE and +@code{get_simple_loop_desc} on RTL. + +Note that some of these functions may behave slightly differently than +others -- some of them return only the expression for the number of +iterations, and fail if there are some assumptions. The function +@code{number_of_iterations_in_loop} works only for single-exit loops, +and it returns the value for number of iterations higher by one with +respect to all other functions (i.e., it returns number of executions of +the exit statement, not of the loop latch). + +@node Dependency analysis +@section Data Dependency Analysis +@cindex Data Dependency Analysis + +The code for the data dependence analysis can be found in +@file{tree-data-ref.c} and its interface and data structures are +described in @file{tree-data-ref.h}. The function that computes the +data dependences for all the array and pointer references for a given +loop is @code{compute_data_dependences_for_loop}. This function is +currently used by the linear loop transform and the vectorization +passes. Before calling this function, one has to allocate two vectors: +a first vector will contain the set of data references that are +contained in the analyzed loop body, and the second vector will contain +the dependence relations between the data references. Thus if the +vector of data references is of size @code{n}, the vector containing the +dependence relations will contain @code{n*n} elements. However if the +analyzed loop contains side effects, such as calls that potentially can +interfere with the data references in the current analyzed loop, the +analysis stops while scanning the loop body for data references, and +inserts a single @code{chrec_dont_know} in the dependence relation +array. + +The data references are discovered in a particular order during the +scanning of the loop body: the loop body is analyzed in execution order, +and the data references of each statement are pushed at the end of the +data reference array. Two data references syntactically occur in the +program in the same order as in the array of data references. This +syntactic order is important in some classical data dependence tests, +and mapping this order to the elements of this array avoids costly +queries to the loop body representation. + +Three types of data references are currently handled: ARRAY_REF, +INDIRECT_REF and COMPONENT_REF. The data structure for the data reference +is @code{data_reference}, where @code{data_reference_p} is a name of a +pointer to the data reference structure. The structure contains the +following elements: + +@itemize +@item @code{base_object_info}: Provides information about the base object +of the data reference and its access functions. These access functions +represent the evolution of the data reference in the loop relative to +its base, in keeping with the classical meaning of the data reference +access function for the support of arrays. For example, for a reference +@code{a.b[i][j]}, the base object is @code{a.b} and the access functions, +one for each array subscript, are: +@code{@{i_init, + i_step@}_1, @{j_init, +, j_step@}_2}. + +@item @code{first_location_in_loop}: Provides information about the first +location accessed by the data reference in the loop and about the access +function used to represent evolution relative to this location. This data +is used to support pointers, and is not used for arrays (for which we +have base objects). Pointer accesses are represented as a one-dimensional +access that starts from the first location accessed in the loop. For +example: + +@smallexample + for1 i + for2 j + *((int *)p + i + j) = a[i][j]; +@end smallexample + +The access function of the pointer access is @code{@{0, + 4B@}_for2} +relative to @code{p + i}. The access functions of the array are +@code{@{i_init, + i_step@}_for1} and @code{@{j_init, +, j_step@}_for2} +relative to @code{a}. + +Usually, the object the pointer refers to is either unknown, or we can't +prove that the access is confined to the boundaries of a certain object. + +Two data references can be compared only if at least one of these two +representations has all its fields filled for both data references. + +The current strategy for data dependence tests is as follows: +If both @code{a} and @code{b} are represented as arrays, compare +@code{a.base_object} and @code{b.base_object}; +if they are equal, apply dependence tests (use access functions based on +base_objects). +Else if both @code{a} and @code{b} are represented as pointers, compare +@code{a.first_location} and @code{b.first_location}; +if they are equal, apply dependence tests (use access functions based on +first location). +However, if @code{a} and @code{b} are represented differently, only try +to prove that the bases are definitely different. + +@item Aliasing information. +@item Alignment information. +@end itemize + +The structure describing the relation between two data references is +@code{data_dependence_relation} and the shorter name for a pointer to +such a structure is @code{ddr_p}. This structure contains: + +@itemize +@item a pointer to each data reference, +@item a tree node @code{are_dependent} that is set to @code{chrec_known} +if the analysis has proved that there is no dependence between these two +data references, @code{chrec_dont_know} if the analysis was not able to +determine any useful result and potentially there could exist a +dependence between these data references, and @code{are_dependent} is +set to @code{NULL_TREE} if there exist a dependence relation between the +data references, and the description of this dependence relation is +given in the @code{subscripts}, @code{dir_vects}, and @code{dist_vects} +arrays, +@item a boolean that determines whether the dependence relation can be +represented by a classical distance vector, +@item an array @code{subscripts} that contains a description of each +subscript of the data references. Given two array accesses a +subscript is the tuple composed of the access functions for a given +dimension. For example, given @code{A[f1][f2][f3]} and +@code{B[g1][g2][g3]}, there are three subscripts: @code{(f1, g1), (f2, +g2), (f3, g3)}. +@item two arrays @code{dir_vects} and @code{dist_vects} that contain +classical representations of the data dependences under the form of +direction and distance dependence vectors, +@item an array of loops @code{loop_nest} that contains the loops to +which the distance and direction vectors refer to. +@end itemize + +Several functions for pretty printing the information extracted by the +data dependence analysis are available: @code{dump_ddrs} prints with a +maximum verbosity the details of a data dependence relations array, +@code{dump_dist_dir_vectors} prints only the classical distance and +direction vectors for a data dependence relations array, and +@code{dump_data_references} prints the details of the data references +contained in a data reference array. + +@node Lambda +@section Linear loop transformations framework +@cindex Linear loop transformations framework + +Lambda is a framework that allows transformations of loops using +non-singular matrix based transformations of the iteration space and +loop bounds. This allows compositions of skewing, scaling, interchange, +and reversal transformations. These transformations are often used to +improve cache behavior or remove inner loop dependencies to allow +parallelization and vectorization to take place. + +To perform these transformations, Lambda requires that the loopnest be +converted into a internal form that can be matrix transformed easily. +To do this conversion, the function +@code{gcc_loopnest_to_lambda_loopnest} is provided. If the loop cannot +be transformed using lambda, this function will return NULL. + +Once a @code{lambda_loopnest} is obtained from the conversion function, +it can be transformed by using @code{lambda_loopnest_transform}, which +takes a transformation matrix to apply. Note that it is up to the +caller to verify that the transformation matrix is legal to apply to the +loop (dependence respecting, etc). Lambda simply applies whatever +matrix it is told to provide. It can be extended to make legal matrices +out of any non-singular matrix, but this is not currently implemented. +Legality of a matrix for a given loopnest can be verified using +@code{lambda_transform_legal_p}. + +Given a transformed loopnest, conversion back into gcc IR is done by +@code{lambda_loopnest_to_gcc_loopnest}. This function will modify the +loops so that they match the transformed loopnest. + diff --git a/gcc-4.2.1-5666.3/gcc/doc/makefile.texi b/gcc-4.2.1-5666.3/gcc/doc/makefile.texi new file mode 100644 index 000000000..f4513b79d --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/makefile.texi @@ -0,0 +1,192 @@ +@c Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Makefile +@subsection Makefile Targets +@cindex makefile targets +@cindex targets, makefile + +These targets are available from the @samp{gcc} directory: + +@table @code +@item all +This is the default target. Depending on what your build/host/target +configuration is, it coordinates all the things that need to be built. + +@item doc +Produce info-formatted documentation and man pages. Essentially it +calls @samp{make man} and @samp{make info}. + +@item dvi +Produce DVI-formatted documentation. + +@item pdf +Produce PDF-formatted documentation. + +@item html +Produce HTML-formatted documentation. + +@item man +Generate man pages. + +@item info +Generate info-formatted pages. + +@item mostlyclean +Delete the files made while building the compiler. + +@item clean +That, and all the other files built by @samp{make all}. + +@item distclean +That, and all the files created by @command{configure}. + +@item maintainer-clean +Distclean plus any file that can be generated from other files. Note +that additional tools may be required beyond what is normally needed to +build gcc. + +@item srcextra +Generates files in the source directory that do not exist in CVS but +should go into a release tarball. One example is @file{gcc/java/parse.c} +which is generated from the CVS source file @file{gcc/java/parse.y}. + +@item srcinfo +@itemx srcman +Copies the info-formatted and manpage documentation into the source +directory usually for the purpose of generating a release tarball. + +@item install +Installs gcc. + +@item uninstall +Deletes installed files. + +@item check +Run the testsuite. This creates a @file{testsuite} subdirectory that +has various @file{.sum} and @file{.log} files containing the results of +the testing. You can run subsets with, for example, @samp{make check-gcc}. +You can specify specific tests by setting RUNTESTFLAGS to be the name +of the @file{.exp} file, optionally followed by (for some tests) an equals +and a file wildcard, like: + +@smallexample +make check-gcc RUNTESTFLAGS="execute.exp=19980413-*" +@end smallexample + +Note that running the testsuite may require additional tools be +installed, such as TCL or dejagnu. +@end table + +The toplevel tree from which you start GCC compilation is not +the GCC directory, but rather a complex Makefile that coordinates +the various steps of the build, including bootstrapping the compiler +and using the new compiler to build target libraries. + +When GCC is configured for a native configuration, the default action +for @command{make} is to do a full three-stage bootstrap. This means +that GCC is built three times---once with the native compiler, once with +the native-built compiler it just built, and once with the compiler it +built the second time. In theory, the last two should produce the same +results, which @samp{make compare} can check. Each stage is configured +separately and compiled into a separate directory, to minimize problems +due to ABI incompatibilities between the native compiler and GCC. + +If you do a change, rebuilding will also start from the first stage +and ``bubble'' up the change through the three stages. Each stage +is taken from its build directory (if it had been built previously), +rebuilt, and copied to its subdirectory. This will allow you to, for +example, continue a bootstrap after fixing a bug which causes the +stage2 build to crash. It does not provide as good coverage of the +compiler as bootstrapping from scratch, but it ensures that the new +code is syntactically correct (e.g. that you did not use GCC extensions +by mistake), and avoids spurious bootstrap comparison +failures@footnote{Except if the compiler was buggy and miscompiled + some of the files that were not modified. In this case, it's best + to use @command{make restrap}.}. + +Other targets available from the top level include: + +@table @code +@item bootstrap-lean +Like @code{bootstrap}, except that the various stages are removed once +they're no longer needed. This saves disk space. + +@item bootstrap2 +@itemx bootstrap2-lean +Performs only the first two stages of bootstrap. Unlike a three-stage +bootstrap, this does not perform a comparison to test that the compiler +is running properly. Note that the disk space required by a ``lean'' +bootstrap is approximately independent of the number of stages. + +@item stage@var{N}-bubble (@var{N} = 1@dots{}4) +Rebuild all the stages up to @var{N}, with the appropriate flags, +``bubbling'' the changes as described above. + +@item all-stage@var{N} (@var{N} = 1@dots{}4) +Assuming that stage @var{N} has already been built, rebuild it with the +appropriate flags. This is rarely needed. + +@item cleanstrap +Remove everything (@samp{make clean}) and rebuilds (@samp{make bootstrap}). + +@item compare +Compares the results of stages 2 and 3. This ensures that the compiler +is running properly, since it should produce the same object files +regardless of how it itself was compiled. + +@item profiledbootstrap +Builds a compiler with profiling feedback information. For more +information, see +@ref{Building,,Building with profile feedback,gccinstall,Installing GCC}. + +@item restrap +Restart a bootstrap, so that everything that was not built with +the system compiler is rebuilt. + +@item stage@var{N}-start (@var{N} = 1@dots{}4) +For each package that is bootstrapped, rename directories so that, +for example, @file{gcc} points to the stage@var{N} GCC, compiled +with the stage@var{N-1} GCC@footnote{Customarily, the system compiler + is also termed the @file{stage0} GCC.}. + +You will invoke this target if you need to test or debug the +stage@var{N} GCC. If you only need to execute GCC (but you need +not run @samp{make} either to rebuild it or to run test suites), +you should be able to work directly in the @file{stage@var{N}-gcc} +directory. This makes it easier to debug multiple stages in +parallel. + +@item stage +For each package that is bootstrapped, relocate its build directory +to indicate its stage. For example, if the @file{gcc} directory +points to the stage2 GCC, after invoking this target it will be +renamed to @file{stage2-gcc}. + +@end table + +If you wish to use non-default GCC flags when compiling the stage2 and +stage3 compilers, set @code{BOOT_CFLAGS} on the command line when doing +@samp{make}. + +Usually, the first stage only builds the languages that the compiler +is written in: typically, C and maybe Ada. If you are debugging a +miscompilation of a different stage2 front-end (for example, of the +Fortran front-end), you may want to have front-ends for other languages +in the first stage as well. To do so, set @code{STAGE1_LANGUAGES} +on the command line when doing @samp{make}. + +For example, in the aforementioned scenario of debugging a Fortran +front-end miscompilation caused by the stage1 compiler, you may need a +command like + +@example +make stage2-bubble STAGE1_LANGUAGES=c,fortran +@end example + +Alternatively, you can use per-language targets to build and test +languages that are not enabled by default in stage1. For example, +@command{make f951} will build a Fortran compiler even in the stage1 +build directory. + diff --git a/gcc-4.2.1-5666.3/gcc/doc/md.texi b/gcc-4.2.1-5666.3/gcc/doc/md.texi new file mode 100644 index 000000000..92e9d31d0 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/md.texi @@ -0,0 +1,7554 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001, +@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@ifset INTERNALS +@node Machine Desc +@chapter Machine Descriptions +@cindex machine descriptions + +A machine description has two parts: a file of instruction patterns +(@file{.md} file) and a C header file of macro definitions. + +The @file{.md} file for a target machine contains a pattern for each +instruction that the target machine supports (or at least each instruction +that is worth telling the compiler about). It may also contain comments. +A semicolon causes the rest of the line to be a comment, unless the semicolon +is inside a quoted string. + +See the next chapter for information on the C header file. + +@menu +* Overview:: How the machine description is used. +* Patterns:: How to write instruction patterns. +* Example:: An explained example of a @code{define_insn} pattern. +* RTL Template:: The RTL template defines what insns match a pattern. +* Output Template:: The output template says how to make assembler code + from such an insn. +* Output Statement:: For more generality, write C code to output + the assembler code. +* Predicates:: Controlling what kinds of operands can be used + for an insn. +* Constraints:: Fine-tuning operand selection. +* Standard Names:: Names mark patterns to use for code generation. +* Pattern Ordering:: When the order of patterns makes a difference. +* Dependent Patterns:: Having one pattern may make you need another. +* Jump Patterns:: Special considerations for patterns for jump insns. +* Looping Patterns:: How to define patterns for special looping insns. +* Insn Canonicalizations::Canonicalization of Instructions +* Expander Definitions::Generating a sequence of several RTL insns + for a standard operation. +* Insn Splitting:: Splitting Instructions into Multiple Instructions. +* Including Patterns:: Including Patterns in Machine Descriptions. +* Peephole Definitions::Defining machine-specific peephole optimizations. +* Insn Attributes:: Specifying the value of attributes for generated insns. +* Conditional Execution::Generating @code{define_insn} patterns for + predication. +* Constant Definitions::Defining symbolic constants that can be used in the + md file. +* Macros:: Using macros to generate patterns from a template. +@end menu + +@node Overview +@section Overview of How the Machine Description is Used + +There are three main conversions that happen in the compiler: + +@enumerate + +@item +The front end reads the source code and builds a parse tree. + +@item +The parse tree is used to generate an RTL insn list based on named +instruction patterns. + +@item +The insn list is matched against the RTL templates to produce assembler +code. + +@end enumerate + +For the generate pass, only the names of the insns matter, from either a +named @code{define_insn} or a @code{define_expand}. The compiler will +choose the pattern with the right name and apply the operands according +to the documentation later in this chapter, without regard for the RTL +template or operand constraints. Note that the names the compiler looks +for are hard-coded in the compiler---it will ignore unnamed patterns and +patterns with names it doesn't know about, but if you don't provide a +named pattern it needs, it will abort. + +If a @code{define_insn} is used, the template given is inserted into the +insn list. If a @code{define_expand} is used, one of three things +happens, based on the condition logic. The condition logic may manually +create new insns for the insn list, say via @code{emit_insn()}, and +invoke @code{DONE}. For certain named patterns, it may invoke @code{FAIL} to tell the +compiler to use an alternate way of performing that task. If it invokes +neither @code{DONE} nor @code{FAIL}, the template given in the pattern +is inserted, as if the @code{define_expand} were a @code{define_insn}. + +Once the insn list is generated, various optimization passes convert, +replace, and rearrange the insns in the insn list. This is where the +@code{define_split} and @code{define_peephole} patterns get used, for +example. + +Finally, the insn list's RTL is matched up with the RTL templates in the +@code{define_insn} patterns, and those patterns are used to emit the +final assembly code. For this purpose, each named @code{define_insn} +acts like it's unnamed, since the names are ignored. + +@node Patterns +@section Everything about Instruction Patterns +@cindex patterns +@cindex instruction patterns + +@findex define_insn +Each instruction pattern contains an incomplete RTL expression, with pieces +to be filled in later, operand constraints that restrict how the pieces can +be filled in, and an output pattern or C code to generate the assembler +output, all wrapped up in a @code{define_insn} expression. + +A @code{define_insn} is an RTL expression containing four or five operands: + +@enumerate +@item +An optional name. The presence of a name indicate that this instruction +pattern can perform a certain standard job for the RTL-generation +pass of the compiler. This pass knows certain names and will use +the instruction patterns with those names, if the names are defined +in the machine description. + +The absence of a name is indicated by writing an empty string +where the name should go. Nameless instruction patterns are never +used for generating RTL code, but they may permit several simpler insns +to be combined later on. + +Names that are not thus known and used in RTL-generation have no +effect; they are equivalent to no name at all. + +For the purpose of debugging the compiler, you may also specify a +name beginning with the @samp{*} character. Such a name is used only +for identifying the instruction in RTL dumps; it is entirely equivalent +to having a nameless pattern for all other purposes. + +@item +The @dfn{RTL template} (@pxref{RTL Template}) is a vector of incomplete +RTL expressions which show what the instruction should look like. It is +incomplete because it may contain @code{match_operand}, +@code{match_operator}, and @code{match_dup} expressions that stand for +operands of the instruction. + +If the vector has only one element, that element is the template for the +instruction pattern. If the vector has multiple elements, then the +instruction pattern is a @code{parallel} expression containing the +elements described. + +@item +@cindex pattern conditions +@cindex conditions, in patterns +A condition. This is a string which contains a C expression that is +the final test to decide whether an insn body matches this pattern. + +@cindex named patterns and conditions +For a named pattern, the condition (if present) may not depend on +the data in the insn being matched, but only the target-machine-type +flags. The compiler needs to test these conditions during +initialization in order to learn exactly which named instructions are +available in a particular run. + +@findex operands +For nameless patterns, the condition is applied only when matching an +individual insn, and only after the insn has matched the pattern's +recognition template. The insn's operands may be found in the vector +@code{operands}. For an insn where the condition has once matched, it +can't be used to control register allocation, for example by excluding +certain hard registers or hard register combinations. + +@item +The @dfn{output template}: a string that says how to output matching +insns as assembler code. @samp{%} in this string specifies where +to substitute the value of an operand. @xref{Output Template}. + +When simple substitution isn't general enough, you can specify a piece +of C code to compute the output. @xref{Output Statement}. + +@item +Optionally, a vector containing the values of attributes for insns matching +this pattern. @xref{Insn Attributes}. +@end enumerate + +@node Example +@section Example of @code{define_insn} +@cindex @code{define_insn} example + +Here is an actual example of an instruction pattern, for the 68000/68020. + +@smallexample +(define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" + "* +@{ + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return \"tstl %0\"; + return \"cmpl #0,%0\"; +@}") +@end smallexample + +@noindent +This can also be written using braced strings: + +@smallexample +(define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" +@{ + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return "tstl %0"; + return "cmpl #0,%0"; +@}) +@end smallexample + +This is an instruction that sets the condition codes based on the value of +a general operand. It has no condition, so any insn whose RTL description +has the form shown may be handled according to this pattern. The name +@samp{tstsi} means ``test a @code{SImode} value'' and tells the RTL generation +pass that, when it is necessary to test such a value, an insn to do so +can be constructed using this pattern. + +The output control string is a piece of C code which chooses which +output template to return based on the kind of operand and the specific +type of CPU for which code is being generated. + +@samp{"rm"} is an operand constraint. Its meaning is explained below. + +@node RTL Template +@section RTL Template +@cindex RTL insn template +@cindex generating insns +@cindex insns, generating +@cindex recognizing insns +@cindex insns, recognizing + +The RTL template is used to define which insns match the particular pattern +and how to find their operands. For named patterns, the RTL template also +says how to construct an insn from specified operands. + +Construction involves substituting specified operands into a copy of the +template. Matching involves determining the values that serve as the +operands in the insn being matched. Both of these activities are +controlled by special expression types that direct matching and +substitution of the operands. + +@table @code +@findex match_operand +@item (match_operand:@var{m} @var{n} @var{predicate} @var{constraint}) +This expression is a placeholder for operand number @var{n} of +the insn. When constructing an insn, operand number @var{n} +will be substituted at this point. When matching an insn, whatever +appears at this position in the insn will be taken as operand +number @var{n}; but it must satisfy @var{predicate} or this instruction +pattern will not match at all. + +Operand numbers must be chosen consecutively counting from zero in +each instruction pattern. There may be only one @code{match_operand} +expression in the pattern for each operand number. Usually operands +are numbered in the order of appearance in @code{match_operand} +expressions. In the case of a @code{define_expand}, any operand numbers +used only in @code{match_dup} expressions have higher values than all +other operand numbers. + +@var{predicate} is a string that is the name of a function that +accepts two arguments, an expression and a machine mode. +@xref{Predicates}. During matching, the function will be called with +the putative operand as the expression and @var{m} as the mode +argument (if @var{m} is not specified, @code{VOIDmode} will be used, +which normally causes @var{predicate} to accept any mode). If it +returns zero, this instruction pattern fails to match. +@var{predicate} may be an empty string; then it means no test is to be +done on the operand, so anything which occurs in this position is +valid. + +Most of the time, @var{predicate} will reject modes other than @var{m}---but +not always. For example, the predicate @code{address_operand} uses +@var{m} as the mode of memory ref that the address should be valid for. +Many predicates accept @code{const_int} nodes even though their mode is +@code{VOIDmode}. + +@var{constraint} controls reloading and the choice of the best register +class to use for a value, as explained later (@pxref{Constraints}). +If the constraint would be an empty string, it can be omitted. + +People are often unclear on the difference between the constraint and the +predicate. The predicate helps decide whether a given insn matches the +pattern. The constraint plays no role in this decision; instead, it +controls various decisions in the case of an insn which does match. + +@findex match_scratch +@item (match_scratch:@var{m} @var{n} @var{constraint}) +This expression is also a placeholder for operand number @var{n} +and indicates that operand must be a @code{scratch} or @code{reg} +expression. + +When matching patterns, this is equivalent to + +@smallexample +(match_operand:@var{m} @var{n} "scratch_operand" @var{pred}) +@end smallexample + +but, when generating RTL, it produces a (@code{scratch}:@var{m}) +expression. + +If the last few expressions in a @code{parallel} are @code{clobber} +expressions whose operands are either a hard register or +@code{match_scratch}, the combiner can add or delete them when +necessary. @xref{Side Effects}. + +@findex match_dup +@item (match_dup @var{n}) +This expression is also a placeholder for operand number @var{n}. +It is used when the operand needs to appear more than once in the +insn. + +In construction, @code{match_dup} acts just like @code{match_operand}: +the operand is substituted into the insn being constructed. But in +matching, @code{match_dup} behaves differently. It assumes that operand +number @var{n} has already been determined by a @code{match_operand} +appearing earlier in the recognition template, and it matches only an +identical-looking expression. + +Note that @code{match_dup} should not be used to tell the compiler that +a particular register is being used for two operands (example: +@code{add} that adds one register to another; the second register is +both an input operand and the output operand). Use a matching +constraint (@pxref{Simple Constraints}) for those. @code{match_dup} is for the cases where one +operand is used in two places in the template, such as an instruction +that computes both a quotient and a remainder, where the opcode takes +two input operands but the RTL template has to refer to each of those +twice; once for the quotient pattern and once for the remainder pattern. + +@findex match_operator +@item (match_operator:@var{m} @var{n} @var{predicate} [@var{operands}@dots{}]) +This pattern is a kind of placeholder for a variable RTL expression +code. + +When constructing an insn, it stands for an RTL expression whose +expression code is taken from that of operand @var{n}, and whose +operands are constructed from the patterns @var{operands}. + +When matching an expression, it matches an expression if the function +@var{predicate} returns nonzero on that expression @emph{and} the +patterns @var{operands} match the operands of the expression. + +Suppose that the function @code{commutative_operator} is defined as +follows, to match any expression whose operator is one of the +commutative arithmetic operators of RTL and whose mode is @var{mode}: + +@smallexample +int +commutative_integer_operator (x, mode) + rtx x; + enum machine_mode mode; +@{ + enum rtx_code code = GET_CODE (x); + if (GET_MODE (x) != mode) + return 0; + return (GET_RTX_CLASS (code) == RTX_COMM_ARITH + || code == EQ || code == NE); +@} +@end smallexample + +Then the following pattern will match any RTL expression consisting +of a commutative operator applied to two general operands: + +@smallexample +(match_operator:SI 3 "commutative_operator" + [(match_operand:SI 1 "general_operand" "g") + (match_operand:SI 2 "general_operand" "g")]) +@end smallexample + +Here the vector @code{[@var{operands}@dots{}]} contains two patterns +because the expressions to be matched all contain two operands. + +When this pattern does match, the two operands of the commutative +operator are recorded as operands 1 and 2 of the insn. (This is done +by the two instances of @code{match_operand}.) Operand 3 of the insn +will be the entire commutative expression: use @code{GET_CODE +(operands[3])} to see which commutative operator was used. + +The machine mode @var{m} of @code{match_operator} works like that of +@code{match_operand}: it is passed as the second argument to the +predicate function, and that function is solely responsible for +deciding whether the expression to be matched ``has'' that mode. + +When constructing an insn, argument 3 of the gen-function will specify +the operation (i.e.@: the expression code) for the expression to be +made. It should be an RTL expression, whose expression code is copied +into a new expression whose operands are arguments 1 and 2 of the +gen-function. The subexpressions of argument 3 are not used; +only its expression code matters. + +When @code{match_operator} is used in a pattern for matching an insn, +it usually best if the operand number of the @code{match_operator} +is higher than that of the actual operands of the insn. This improves +register allocation because the register allocator often looks at +operands 1 and 2 of insns to see if it can do register tying. + +There is no way to specify constraints in @code{match_operator}. The +operand of the insn which corresponds to the @code{match_operator} +never has any constraints because it is never reloaded as a whole. +However, if parts of its @var{operands} are matched by +@code{match_operand} patterns, those parts may have constraints of +their own. + +@findex match_op_dup +@item (match_op_dup:@var{m} @var{n}[@var{operands}@dots{}]) +Like @code{match_dup}, except that it applies to operators instead of +operands. When constructing an insn, operand number @var{n} will be +substituted at this point. But in matching, @code{match_op_dup} behaves +differently. It assumes that operand number @var{n} has already been +determined by a @code{match_operator} appearing earlier in the +recognition template, and it matches only an identical-looking +expression. + +@findex match_parallel +@item (match_parallel @var{n} @var{predicate} [@var{subpat}@dots{}]) +This pattern is a placeholder for an insn that consists of a +@code{parallel} expression with a variable number of elements. This +expression should only appear at the top level of an insn pattern. + +When constructing an insn, operand number @var{n} will be substituted at +this point. When matching an insn, it matches if the body of the insn +is a @code{parallel} expression with at least as many elements as the +vector of @var{subpat} expressions in the @code{match_parallel}, if each +@var{subpat} matches the corresponding element of the @code{parallel}, +@emph{and} the function @var{predicate} returns nonzero on the +@code{parallel} that is the body of the insn. It is the responsibility +of the predicate to validate elements of the @code{parallel} beyond +those listed in the @code{match_parallel}. + +A typical use of @code{match_parallel} is to match load and store +multiple expressions, which can contain a variable number of elements +in a @code{parallel}. For example, + +@smallexample +(define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI 179)) + (clobber (reg:SI 179))])] + "" + "loadm 0,0,%1,%2") +@end smallexample + +This example comes from @file{a29k.md}. The function +@code{load_multiple_operation} is defined in @file{a29k.c} and checks +that subsequent elements in the @code{parallel} are the same as the +@code{set} in the pattern, except that they are referencing subsequent +registers and memory locations. + +An insn that matches this pattern might look like: + +@smallexample +(parallel + [(set (reg:SI 20) (mem:SI (reg:SI 100))) + (use (reg:SI 179)) + (clobber (reg:SI 179)) + (set (reg:SI 21) + (mem:SI (plus:SI (reg:SI 100) + (const_int 4)))) + (set (reg:SI 22) + (mem:SI (plus:SI (reg:SI 100) + (const_int 8))))]) +@end smallexample + +@findex match_par_dup +@item (match_par_dup @var{n} [@var{subpat}@dots{}]) +Like @code{match_op_dup}, but for @code{match_parallel} instead of +@code{match_operator}. + +@end table + +@node Output Template +@section Output Templates and Operand Substitution +@cindex output templates +@cindex operand substitution + +@cindex @samp{%} in template +@cindex percent sign +The @dfn{output template} is a string which specifies how to output the +assembler code for an instruction pattern. Most of the template is a +fixed string which is output literally. The character @samp{%} is used +to specify where to substitute an operand; it can also be used to +identify places where different variants of the assembler require +different syntax. + +In the simplest case, a @samp{%} followed by a digit @var{n} says to output +operand @var{n} at that point in the string. + +@samp{%} followed by a letter and a digit says to output an operand in an +alternate fashion. Four letters have standard, built-in meanings described +below. The machine description macro @code{PRINT_OPERAND} can define +additional letters with nonstandard meanings. + +@samp{%c@var{digit}} can be used to substitute an operand that is a +constant value without the syntax that normally indicates an immediate +operand. + +@samp{%n@var{digit}} is like @samp{%c@var{digit}} except that the value of +the constant is negated before printing. + +@samp{%a@var{digit}} can be used to substitute an operand as if it were a +memory reference, with the actual operand treated as the address. This may +be useful when outputting a ``load address'' instruction, because often the +assembler syntax for such an instruction requires you to write the operand +as if it were a memory reference. + +@samp{%l@var{digit}} is used to substitute a @code{label_ref} into a jump +instruction. + +@samp{%=} outputs a number which is unique to each instruction in the +entire compilation. This is useful for making local labels to be +referred to more than once in a single template that generates multiple +assembler instructions. + +@samp{%} followed by a punctuation character specifies a substitution that +does not use an operand. Only one case is standard: @samp{%%} outputs a +@samp{%} into the assembler code. Other nonstandard cases can be +defined in the @code{PRINT_OPERAND} macro. You must also define +which punctuation characters are valid with the +@code{PRINT_OPERAND_PUNCT_VALID_P} macro. + +@cindex \ +@cindex backslash +The template may generate multiple assembler instructions. Write the text +for the instructions, with @samp{\;} between them. + +@cindex matching operands +When the RTL contains two operands which are required by constraint to match +each other, the output template must refer only to the lower-numbered operand. +Matching operands are not always identical, and the rest of the compiler +arranges to put the proper RTL expression for printing into the lower-numbered +operand. + +One use of nonstandard letters or punctuation following @samp{%} is to +distinguish between different assembler languages for the same machine; for +example, Motorola syntax versus MIT syntax for the 68000. Motorola syntax +requires periods in most opcode names, while MIT syntax does not. For +example, the opcode @samp{movel} in MIT syntax is @samp{move.l} in Motorola +syntax. The same file of patterns is used for both kinds of output syntax, +but the character sequence @samp{%.} is used in each place where Motorola +syntax wants a period. The @code{PRINT_OPERAND} macro for Motorola syntax +defines the sequence to output a period; the macro for MIT syntax defines +it to do nothing. + +@cindex @code{#} in template +As a special case, a template consisting of the single character @code{#} +instructs the compiler to first split the insn, and then output the +resulting instructions separately. This helps eliminate redundancy in the +output templates. If you have a @code{define_insn} that needs to emit +multiple assembler instructions, and there is an matching @code{define_split} +already defined, then you can simply use @code{#} as the output template +instead of writing an output template that emits the multiple assembler +instructions. + +If the macro @code{ASSEMBLER_DIALECT} is defined, you can use construct +of the form @samp{@{option0|option1|option2@}} in the templates. These +describe multiple variants of assembler language syntax. +@xref{Instruction Output}. + +@node Output Statement +@section C Statements for Assembler Output +@cindex output statements +@cindex C statements for assembler output +@cindex generating assembler output + +Often a single fixed template string cannot produce correct and efficient +assembler code for all the cases that are recognized by a single +instruction pattern. For example, the opcodes may depend on the kinds of +operands; or some unfortunate combinations of operands may require extra +machine instructions. + +If the output control string starts with a @samp{@@}, then it is actually +a series of templates, each on a separate line. (Blank lines and +leading spaces and tabs are ignored.) The templates correspond to the +pattern's constraint alternatives (@pxref{Multi-Alternative}). For example, +if a target machine has a two-address add instruction @samp{addr} to add +into a register and another @samp{addm} to add a register to memory, you +might write this pattern: + +@smallexample +(define_insn "addsi3" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (plus:SI (match_operand:SI 1 "general_operand" "0,0") + (match_operand:SI 2 "general_operand" "g,r")))] + "" + "@@ + addr %2,%0 + addm %2,%0") +@end smallexample + +@cindex @code{*} in template +@cindex asterisk in template +If the output control string starts with a @samp{*}, then it is not an +output template but rather a piece of C program that should compute a +template. It should execute a @code{return} statement to return the +template-string you want. Most such templates use C string literals, which +require doublequote characters to delimit them. To include these +doublequote characters in the string, prefix each one with @samp{\}. + +If the output control string is written as a brace block instead of a +double-quoted string, it is automatically assumed to be C code. In that +case, it is not necessary to put in a leading asterisk, or to escape the +doublequotes surrounding C string literals. + +The operands may be found in the array @code{operands}, whose C data type +is @code{rtx []}. + +It is very common to select different ways of generating assembler code +based on whether an immediate operand is within a certain range. Be +careful when doing this, because the result of @code{INTVAL} is an +integer on the host machine. If the host machine has more bits in an +@code{int} than the target machine has in the mode in which the constant +will be used, then some of the bits you get from @code{INTVAL} will be +superfluous. For proper results, you must carefully disregard the +values of those bits. + +@findex output_asm_insn +It is possible to output an assembler instruction and then go on to output +or compute more of them, using the subroutine @code{output_asm_insn}. This +receives two arguments: a template-string and a vector of operands. The +vector may be @code{operands}, or it may be another array of @code{rtx} +that you declare locally and initialize yourself. + +@findex which_alternative +When an insn pattern has multiple alternatives in its constraints, often +the appearance of the assembler code is determined mostly by which alternative +was matched. When this is so, the C code can test the variable +@code{which_alternative}, which is the ordinal number of the alternative +that was actually satisfied (0 for the first, 1 for the second alternative, +etc.). + +For example, suppose there are two opcodes for storing zero, @samp{clrreg} +for registers and @samp{clrmem} for memory locations. Here is how +a pattern could use @code{which_alternative} to choose between them: + +@smallexample +(define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (const_int 0))] + "" + @{ + return (which_alternative == 0 + ? "clrreg %0" : "clrmem %0"); + @}) +@end smallexample + +The example above, where the assembler code to generate was +@emph{solely} determined by the alternative, could also have been specified +as follows, having the output control string start with a @samp{@@}: + +@smallexample +@group +(define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (const_int 0))] + "" + "@@ + clrreg %0 + clrmem %0") +@end group +@end smallexample + +@node Predicates +@section Predicates +@cindex predicates +@cindex operand predicates +@cindex operator predicates + +A predicate determines whether a @code{match_operand} or +@code{match_operator} expression matches, and therefore whether the +surrounding instruction pattern will be used for that combination of +operands. GCC has a number of machine-independent predicates, and you +can define machine-specific predicates as needed. By convention, +predicates used with @code{match_operand} have names that end in +@samp{_operand}, and those used with @code{match_operator} have names +that end in @samp{_operator}. + +All predicates are Boolean functions (in the mathematical sense) of +two arguments: the RTL expression that is being considered at that +position in the instruction pattern, and the machine mode that the +@code{match_operand} or @code{match_operator} specifies. In this +section, the first argument is called @var{op} and the second argument +@var{mode}. Predicates can be called from C as ordinary two-argument +functions; this can be useful in output templates or other +machine-specific code. + +Operand predicates can allow operands that are not actually acceptable +to the hardware, as long as the constraints give reload the ability to +fix them up (@pxref{Constraints}). However, GCC will usually generate +better code if the predicates specify the requirements of the machine +instructions as closely as possible. Reload cannot fix up operands +that must be constants (``immediate operands''); you must use a +predicate that allows only constants, or else enforce the requirement +in the extra condition. + +@cindex predicates and machine modes +@cindex normal predicates +@cindex special predicates +Most predicates handle their @var{mode} argument in a uniform manner. +If @var{mode} is @code{VOIDmode} (unspecified), then @var{op} can have +any mode. If @var{mode} is anything else, then @var{op} must have the +same mode, unless @var{op} is a @code{CONST_INT} or integer +@code{CONST_DOUBLE}. These RTL expressions always have +@code{VOIDmode}, so it would be counterproductive to check that their +mode matches. Instead, predicates that accept @code{CONST_INT} and/or +integer @code{CONST_DOUBLE} check that the value stored in the +constant will fit in the requested mode. + +Predicates with this behavior are called @dfn{normal}. +@command{genrecog} can optimize the instruction recognizer based on +knowledge of how normal predicates treat modes. It can also diagnose +certain kinds of common errors in the use of normal predicates; for +instance, it is almost always an error to use a normal predicate +without specifying a mode. + +Predicates that do something different with their @var{mode} argument +are called @dfn{special}. The generic predicates +@code{address_operand} and @code{pmode_register_operand} are special +predicates. @command{genrecog} does not do any optimizations or +diagnosis when special predicates are used. + +@menu +* Machine-Independent Predicates:: Predicates available to all back ends. +* Defining Predicates:: How to write machine-specific predicate + functions. +@end menu + +@node Machine-Independent Predicates +@subsection Machine-Independent Predicates +@cindex machine-independent predicates +@cindex generic predicates + +These are the generic predicates available to all back ends. They are +defined in @file{recog.c}. The first category of predicates allow +only constant, or @dfn{immediate}, operands. + +@defun immediate_operand +This predicate allows any sort of constant that fits in @var{mode}. +It is an appropriate choice for instructions that take operands that +must be constant. +@end defun + +@defun const_int_operand +This predicate allows any @code{CONST_INT} expression that fits in +@var{mode}. It is an appropriate choice for an immediate operand that +does not allow a symbol or label. +@end defun + +@defun const_double_operand +This predicate accepts any @code{CONST_DOUBLE} expression that has +exactly @var{mode}. If @var{mode} is @code{VOIDmode}, it will also +accept @code{CONST_INT}. It is intended for immediate floating point +constants. +@end defun + +@noindent +The second category of predicates allow only some kind of machine +register. + +@defun register_operand +This predicate allows any @code{REG} or @code{SUBREG} expression that +is valid for @var{mode}. It is often suitable for arithmetic +instruction operands on a RISC machine. +@end defun + +@defun pmode_register_operand +This is a slight variant on @code{register_operand} which works around +a limitation in the machine-description reader. + +@smallexample +(match_operand @var{n} "pmode_register_operand" @var{constraint}) +@end smallexample + +@noindent +means exactly what + +@smallexample +(match_operand:P @var{n} "register_operand" @var{constraint}) +@end smallexample + +@noindent +would mean, if the machine-description reader accepted @samp{:P} +mode suffixes. Unfortunately, it cannot, because @code{Pmode} is an +alias for some other mode, and might vary with machine-specific +options. @xref{Misc}. +@end defun + +@defun scratch_operand +This predicate allows hard registers and @code{SCRATCH} expressions, +but not pseudo-registers. It is used internally by @code{match_scratch}; +it should not be used directly. +@end defun + +@noindent +The third category of predicates allow only some kind of memory reference. + +@defun memory_operand +This predicate allows any valid reference to a quantity of mode +@var{mode} in memory, as determined by the weak form of +@code{GO_IF_LEGITIMATE_ADDRESS} (@pxref{Addressing Modes}). +@end defun + +@defun address_operand +This predicate is a little unusual; it allows any operand that is a +valid expression for the @emph{address} of a quantity of mode +@var{mode}, again determined by the weak form of +@code{GO_IF_LEGITIMATE_ADDRESS}. To first order, if +@samp{@w{(mem:@var{mode} (@var{exp}))}} is acceptable to +@code{memory_operand}, then @var{exp} is acceptable to +@code{address_operand}. Note that @var{exp} does not necessarily have +the mode @var{mode}. +@end defun + +@defun indirect_operand +This is a stricter form of @code{memory_operand} which allows only +memory references with a @code{general_operand} as the address +expression. New uses of this predicate are discouraged, because +@code{general_operand} is very permissive, so it's hard to tell what +an @code{indirect_operand} does or does not allow. If a target has +different requirements for memory operands for different instructions, +it is better to define target-specific predicates which enforce the +hardware's requirements explicitly. +@end defun + +@defun push_operand +This predicate allows a memory reference suitable for pushing a value +onto the stack. This will be a @code{MEM} which refers to +@code{stack_pointer_rtx}, with a side-effect in its address expression +(@pxref{Incdec}); which one is determined by the +@code{STACK_PUSH_CODE} macro (@pxref{Frame Layout}). +@end defun + +@defun pop_operand +This predicate allows a memory reference suitable for popping a value +off the stack. Again, this will be a @code{MEM} referring to +@code{stack_pointer_rtx}, with a side-effect in its address +expression. However, this time @code{STACK_POP_CODE} is expected. +@end defun + +@noindent +The fourth category of predicates allow some combination of the above +operands. + +@defun nonmemory_operand +This predicate allows any immediate or register operand valid for @var{mode}. +@end defun + +@defun nonimmediate_operand +This predicate allows any register or memory operand valid for @var{mode}. +@end defun + +@defun general_operand +This predicate allows any immediate, register, or memory operand +valid for @var{mode}. +@end defun + +@noindent +Finally, there is one generic operator predicate. + +@defun comparison_operator +This predicate matches any expression which performs an arithmetic +comparison in @var{mode}; that is, @code{COMPARISON_P} is true for the +expression code. +@end defun + +@node Defining Predicates +@subsection Defining Machine-Specific Predicates +@cindex defining predicates +@findex define_predicate +@findex define_special_predicate + +Many machines have requirements for their operands that cannot be +expressed precisely using the generic predicates. You can define +additional predicates using @code{define_predicate} and +@code{define_special_predicate} expressions. These expressions have +three operands: + +@itemize @bullet +@item +The name of the predicate, as it will be referred to in +@code{match_operand} or @code{match_operator} expressions. + +@item +An RTL expression which evaluates to true if the predicate allows the +operand @var{op}, false if it does not. This expression can only use +the following RTL codes: + +@table @code +@item MATCH_OPERAND +When written inside a predicate expression, a @code{MATCH_OPERAND} +expression evaluates to true if the predicate it names would allow +@var{op}. The operand number and constraint are ignored. Due to +limitations in @command{genrecog}, you can only refer to generic +predicates and predicates that have already been defined. + +@item MATCH_CODE +This expression evaluates to true if @var{op} or a specified +subexpression of @var{op} has one of a given list of RTX codes. + +The first operand of this expression is a string constant containing a +comma-separated list of RTX code names (in lower case). These are the +codes for which the @code{MATCH_CODE} will be true. + +The second operand is a string constant which indicates what +subexpression of @var{op} to examine. If it is absent or the empty +string, @var{op} itself is examined. Otherwise, the string constant +must be a sequence of digits and/or lowercase letters. Each character +indicates a subexpression to extract from the current expression; for +the first character this is @var{op}, for the second and subsequent +characters it is the result of the previous character. A digit +@var{n} extracts @samp{@w{XEXP (@var{e}, @var{n})}}; a letter @var{l} +extracts @samp{@w{XVECEXP (@var{e}, 0, @var{n})}} where @var{n} is the +alphabetic ordinal of @var{l} (0 for `a', 1 for 'b', and so on). The +@code{MATCH_CODE} then examines the RTX code of the subexpression +extracted by the complete string. It is not possible to extract +components of an @code{rtvec} that is not at position 0 within its RTX +object. + +@item MATCH_TEST +This expression has one operand, a string constant containing a C +expression. The predicate's arguments, @var{op} and @var{mode}, are +available with those names in the C expression. The @code{MATCH_TEST} +evaluates to true if the C expression evaluates to a nonzero value. +@code{MATCH_TEST} expressions must not have side effects. + +@item AND +@itemx IOR +@itemx NOT +@itemx IF_THEN_ELSE +The basic @samp{MATCH_} expressions can be combined using these +logical operators, which have the semantics of the C operators +@samp{&&}, @samp{||}, @samp{!}, and @samp{@w{? :}} respectively. As +in Common Lisp, you may give an @code{AND} or @code{IOR} expression an +arbitrary number of arguments; this has exactly the same effect as +writing a chain of two-argument @code{AND} or @code{IOR} expressions. +@end table + +@item +An optional block of C code, which should execute +@samp{@w{return true}} if the predicate is found to match and +@samp{@w{return false}} if it does not. It must not have any side +effects. The predicate arguments, @var{op} and @var{mode}, are +available with those names. + +If a code block is present in a predicate definition, then the RTL +expression must evaluate to true @emph{and} the code block must +execute @samp{@w{return true}} for the predicate to allow the operand. +The RTL expression is evaluated first; do not re-check anything in the +code block that was checked in the RTL expression. +@end itemize + +The program @command{genrecog} scans @code{define_predicate} and +@code{define_special_predicate} expressions to determine which RTX +codes are possibly allowed. You should always make this explicit in +the RTL predicate expression, using @code{MATCH_OPERAND} and +@code{MATCH_CODE}. + +Here is an example of a simple predicate definition, from the IA64 +machine description: + +@smallexample +@group +;; @r{True if @var{op} is a @code{SYMBOL_REF} which refers to the sdata section.} +(define_predicate "small_addr_symbolic_operand" + (and (match_code "symbol_ref") + (match_test "SYMBOL_REF_SMALL_ADDR_P (op)"))) +@end group +@end smallexample + +@noindent +And here is another, showing the use of the C block. + +@smallexample +@group +;; @r{True if @var{op} is a register operand that is (or could be) a GR reg.} +(define_predicate "gr_register_operand" + (match_operand 0 "register_operand") +@{ + unsigned int regno; + if (GET_CODE (op) == SUBREG) + op = SUBREG_REG (op); + + regno = REGNO (op); + return (regno >= FIRST_PSEUDO_REGISTER || GENERAL_REGNO_P (regno)); +@}) +@end group +@end smallexample + +Predicates written with @code{define_predicate} automatically include +a test that @var{mode} is @code{VOIDmode}, or @var{op} has the same +mode as @var{mode}, or @var{op} is a @code{CONST_INT} or +@code{CONST_DOUBLE}. They do @emph{not} check specifically for +integer @code{CONST_DOUBLE}, nor do they test that the value of either +kind of constant fits in the requested mode. This is because +target-specific predicates that take constants usually have to do more +stringent value checks anyway. If you need the exact same treatment +of @code{CONST_INT} or @code{CONST_DOUBLE} that the generic predicates +provide, use a @code{MATCH_OPERAND} subexpression to call +@code{const_int_operand}, @code{const_double_operand}, or +@code{immediate_operand}. + +Predicates written with @code{define_special_predicate} do not get any +automatic mode checks, and are treated as having special mode handling +by @command{genrecog}. + +The program @command{genpreds} is responsible for generating code to +test predicates. It also writes a header file containing function +declarations for all machine-specific predicates. It is not necessary +to declare these predicates in @file{@var{cpu}-protos.h}. +@end ifset + +@c Most of this node appears by itself (in a different place) even +@c when the INTERNALS flag is clear. Passages that require the internals +@c manual's context are conditionalized to appear only in the internals manual. +@ifset INTERNALS +@node Constraints +@section Operand Constraints +@cindex operand constraints +@cindex constraints + +Each @code{match_operand} in an instruction pattern can specify +constraints for the operands allowed. The constraints allow you to +fine-tune matching within the set of operands allowed by the +predicate. + +@end ifset +@ifclear INTERNALS +@node Constraints +@section Constraints for @code{asm} Operands +@cindex operand constraints, @code{asm} +@cindex constraints, @code{asm} +@cindex @code{asm} constraints + +Here are specific details on what constraint letters you can use with +@code{asm} operands. +@end ifclear +Constraints can say whether +an operand may be in a register, and which kinds of register; whether the +operand can be a memory reference, and which kinds of address; whether the +operand may be an immediate constant, and which possible values it may +have. Constraints can also require two operands to match. + +@ifset INTERNALS +@menu +* Simple Constraints:: Basic use of constraints. +* Multi-Alternative:: When an insn has two alternative constraint-patterns. +* Class Preferences:: Constraints guide which hard register to put things in. +* Modifiers:: More precise control over effects of constraints. +* Machine Constraints:: Existing constraints for some particular machines. +* Define Constraints:: How to define machine-specific constraints. +* C Constraint Interface:: How to test constraints from C code. +@end menu +@end ifset + +@ifclear INTERNALS +@menu +* Simple Constraints:: Basic use of constraints. +* Multi-Alternative:: When an insn has two alternative constraint-patterns. +* Modifiers:: More precise control over effects of constraints. +* Machine Constraints:: Special constraints for some particular machines. +@end menu +@end ifclear + +@node Simple Constraints +@subsection Simple Constraints +@cindex simple constraints + +The simplest kind of constraint is a string full of letters, each of +which describes one kind of operand that is permitted. Here are +the letters that are allowed: + +@table @asis +@item whitespace +Whitespace characters are ignored and can be inserted at any position +except the first. This enables each alternative for different operands to +be visually aligned in the machine description even if they have different +number of constraints and modifiers. + +@cindex @samp{m} in constraint +@cindex memory references in constraints +@item @samp{m} +A memory operand is allowed, with any kind of address that the machine +supports in general. + +@cindex offsettable address +@cindex @samp{o} in constraint +@item @samp{o} +A memory operand is allowed, but only if the address is +@dfn{offsettable}. This means that adding a small integer (actually, +the width in bytes of the operand, as determined by its machine mode) +may be added to the address and the result is also a valid memory +address. + +@cindex autoincrement/decrement addressing +For example, an address which is constant is offsettable; so is an +address that is the sum of a register and a constant (as long as a +slightly larger constant is also within the range of address-offsets +supported by the machine); but an autoincrement or autodecrement +address is not offsettable. More complicated indirect/indexed +addresses may or may not be offsettable depending on the other +addressing modes that the machine supports. + +Note that in an output operand which can be matched by another +operand, the constraint letter @samp{o} is valid only when accompanied +by both @samp{<} (if the target machine has predecrement addressing) +and @samp{>} (if the target machine has preincrement addressing). + +@cindex @samp{V} in constraint +@item @samp{V} +A memory operand that is not offsettable. In other words, anything that +would fit the @samp{m} constraint but not the @samp{o} constraint. + +@cindex @samp{<} in constraint +@item @samp{<} +A memory operand with autodecrement addressing (either predecrement or +postdecrement) is allowed. + +@cindex @samp{>} in constraint +@item @samp{>} +A memory operand with autoincrement addressing (either preincrement or +postincrement) is allowed. + +@cindex @samp{r} in constraint +@cindex registers in constraints +@item @samp{r} +A register operand is allowed provided that it is in a general +register. + +@cindex constants in constraints +@cindex @samp{i} in constraint +@item @samp{i} +An immediate integer operand (one with constant value) is allowed. +This includes symbolic constants whose values will be known only at +assembly time or later. + +@cindex @samp{n} in constraint +@item @samp{n} +An immediate integer operand with a known numeric value is allowed. +Many systems cannot support assembly-time constants for operands less +than a word wide. Constraints for these operands should use @samp{n} +rather than @samp{i}. + +@cindex @samp{I} in constraint +@item @samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P} +Other letters in the range @samp{I} through @samp{P} may be defined in +a machine-dependent fashion to permit immediate integer operands with +explicit integer values in specified ranges. For example, on the +68000, @samp{I} is defined to stand for the range of values 1 to 8. +This is the range permitted as a shift count in the shift +instructions. + +@cindex @samp{E} in constraint +@item @samp{E} +An immediate floating operand (expression code @code{const_double}) is +allowed, but only if the target floating point format is the same as +that of the host machine (on which the compiler is running). + +@cindex @samp{F} in constraint +@item @samp{F} +An immediate floating operand (expression code @code{const_double} or +@code{const_vector}) is allowed. + +@cindex @samp{G} in constraint +@cindex @samp{H} in constraint +@item @samp{G}, @samp{H} +@samp{G} and @samp{H} may be defined in a machine-dependent fashion to +permit immediate floating operands in particular ranges of values. + +@cindex @samp{s} in constraint +@item @samp{s} +An immediate integer operand whose value is not an explicit integer is +allowed. + +This might appear strange; if an insn allows a constant operand with a +value not known at compile time, it certainly must allow any known +value. So why use @samp{s} instead of @samp{i}? Sometimes it allows +better code to be generated. + +For example, on the 68000 in a fullword instruction it is possible to +use an immediate operand; but if the immediate value is between @minus{}128 +and 127, better code results from loading the value into a register and +using the register. This is because the load into the register can be +done with a @samp{moveq} instruction. We arrange for this to happen +by defining the letter @samp{K} to mean ``any integer outside the +range @minus{}128 to 127'', and then specifying @samp{Ks} in the operand +constraints. + +@cindex @samp{g} in constraint +@item @samp{g} +Any register, memory or immediate integer operand is allowed, except for +registers that are not general registers. + +@cindex @samp{X} in constraint +@item @samp{X} +@ifset INTERNALS +Any operand whatsoever is allowed, even if it does not satisfy +@code{general_operand}. This is normally used in the constraint of +a @code{match_scratch} when certain alternatives will not actually +require a scratch register. +@end ifset +@ifclear INTERNALS +Any operand whatsoever is allowed. +@end ifclear + +@cindex @samp{0} in constraint +@cindex digits in constraint +@item @samp{0}, @samp{1}, @samp{2}, @dots{} @samp{9} +An operand that matches the specified operand number is allowed. If a +digit is used together with letters within the same alternative, the +digit should come last. + +This number is allowed to be more than a single digit. If multiple +digits are encountered consecutively, they are interpreted as a single +decimal integer. There is scant chance for ambiguity, since to-date +it has never been desirable that @samp{10} be interpreted as matching +either operand 1 @emph{or} operand 0. Should this be desired, one +can use multiple alternatives instead. + +@cindex matching constraint +@cindex constraint, matching +This is called a @dfn{matching constraint} and what it really means is +that the assembler has only a single operand that fills two roles +@ifset INTERNALS +considered separate in the RTL insn. For example, an add insn has two +input operands and one output operand in the RTL, but on most CISC +@end ifset +@ifclear INTERNALS +which @code{asm} distinguishes. For example, an add instruction uses +two input operands and an output operand, but on most CISC +@end ifclear +machines an add instruction really has only two operands, one of them an +input-output operand: + +@smallexample +addl #35,r12 +@end smallexample + +Matching constraints are used in these circumstances. +More precisely, the two operands that match must include one input-only +operand and one output-only operand. Moreover, the digit must be a +smaller number than the number of the operand that uses it in the +constraint. + +@ifset INTERNALS +For operands to match in a particular case usually means that they +are identical-looking RTL expressions. But in a few special cases +specific kinds of dissimilarity are allowed. For example, @code{*x} +as an input operand will match @code{*x++} as an output operand. +For proper results in such cases, the output template should always +use the output-operand's number when printing the operand. +@end ifset + +@cindex load address instruction +@cindex push address instruction +@cindex address constraints +@cindex @samp{p} in constraint +@item @samp{p} +An operand that is a valid memory address is allowed. This is +for ``load address'' and ``push address'' instructions. + +@findex address_operand +@samp{p} in the constraint must be accompanied by @code{address_operand} +as the predicate in the @code{match_operand}. This predicate interprets +the mode specified in the @code{match_operand} as the mode of the memory +reference for which the address would be valid. + +@cindex other register constraints +@cindex extensible constraints +@item @var{other-letters} +Other letters can be defined in machine-dependent fashion to stand for +particular classes of registers or other arbitrary operand types. +@samp{d}, @samp{a} and @samp{f} are defined on the 68000/68020 to stand +for data, address and floating point registers. +@end table + +@ifset INTERNALS +In order to have valid assembler code, each operand must satisfy +its constraint. But a failure to do so does not prevent the pattern +from applying to an insn. Instead, it directs the compiler to modify +the code so that the constraint will be satisfied. Usually this is +done by copying an operand into a register. + +Contrast, therefore, the two instruction patterns that follow: + +@smallexample +(define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r") + (plus:SI (match_dup 0) + (match_operand:SI 1 "general_operand" "r")))] + "" + "@dots{}") +@end smallexample + +@noindent +which has two operands, one of which must appear in two places, and + +@smallexample +(define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r") + (plus:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "r")))] + "" + "@dots{}") +@end smallexample + +@noindent +which has three operands, two of which are required by a constraint to be +identical. If we are considering an insn of the form + +@smallexample +(insn @var{n} @var{prev} @var{next} + (set (reg:SI 3) + (plus:SI (reg:SI 6) (reg:SI 109))) + @dots{}) +@end smallexample + +@noindent +the first pattern would not apply at all, because this insn does not +contain two identical subexpressions in the right place. The pattern would +say, ``That does not look like an add instruction; try other patterns''. +The second pattern would say, ``Yes, that's an add instruction, but there +is something wrong with it''. It would direct the reload pass of the +compiler to generate additional insns to make the constraint true. The +results might look like this: + +@smallexample +(insn @var{n2} @var{prev} @var{n} + (set (reg:SI 3) (reg:SI 6)) + @dots{}) + +(insn @var{n} @var{n2} @var{next} + (set (reg:SI 3) + (plus:SI (reg:SI 3) (reg:SI 109))) + @dots{}) +@end smallexample + +It is up to you to make sure that each operand, in each pattern, has +constraints that can handle any RTL expression that could be present for +that operand. (When multiple alternatives are in use, each pattern must, +for each possible combination of operand expressions, have at least one +alternative which can handle that combination of operands.) The +constraints don't need to @emph{allow} any possible operand---when this is +the case, they do not constrain---but they must at least point the way to +reloading any possible operand so that it will fit. + +@itemize @bullet +@item +If the constraint accepts whatever operands the predicate permits, +there is no problem: reloading is never necessary for this operand. + +For example, an operand whose constraints permit everything except +registers is safe provided its predicate rejects registers. + +An operand whose predicate accepts only constant values is safe +provided its constraints include the letter @samp{i}. If any possible +constant value is accepted, then nothing less than @samp{i} will do; +if the predicate is more selective, then the constraints may also be +more selective. + +@item +Any operand expression can be reloaded by copying it into a register. +So if an operand's constraints allow some kind of register, it is +certain to be safe. It need not permit all classes of registers; the +compiler knows how to copy a register into another register of the +proper class in order to make an instruction valid. + +@cindex nonoffsettable memory reference +@cindex memory reference, nonoffsettable +@item +A nonoffsettable memory reference can be reloaded by copying the +address into a register. So if the constraint uses the letter +@samp{o}, all memory references are taken care of. + +@item +A constant operand can be reloaded by allocating space in memory to +hold it as preinitialized data. Then the memory reference can be used +in place of the constant. So if the constraint uses the letters +@samp{o} or @samp{m}, constant operands are not a problem. + +@item +If the constraint permits a constant and a pseudo register used in an insn +was not allocated to a hard register and is equivalent to a constant, +the register will be replaced with the constant. If the predicate does +not permit a constant and the insn is re-recognized for some reason, the +compiler will crash. Thus the predicate must always recognize any +objects allowed by the constraint. +@end itemize + +If the operand's predicate can recognize registers, but the constraint does +not permit them, it can make the compiler crash. When this operand happens +to be a register, the reload pass will be stymied, because it does not know +how to copy a register temporarily into memory. + +If the predicate accepts a unary operator, the constraint applies to the +operand. For example, the MIPS processor at ISA level 3 supports an +instruction which adds two registers in @code{SImode} to produce a +@code{DImode} result, but only if the registers are correctly sign +extended. This predicate for the input operands accepts a +@code{sign_extend} of an @code{SImode} register. Write the constraint +to indicate the type of register that is required for the operand of the +@code{sign_extend}. +@end ifset + +@node Multi-Alternative +@subsection Multiple Alternative Constraints +@cindex multiple alternative constraints + +Sometimes a single instruction has multiple alternative sets of possible +operands. For example, on the 68000, a logical-or instruction can combine +register or an immediate value into memory, or it can combine any kind of +operand into a register; but it cannot combine one memory location into +another. + +These constraints are represented as multiple alternatives. An alternative +can be described by a series of letters for each operand. The overall +constraint for an operand is made from the letters for this operand +from the first alternative, a comma, the letters for this operand from +the second alternative, a comma, and so on until the last alternative. +@ifset INTERNALS +Here is how it is done for fullword logical-or on the 68000: + +@smallexample +(define_insn "iorsi3" + [(set (match_operand:SI 0 "general_operand" "=m,d") + (ior:SI (match_operand:SI 1 "general_operand" "%0,0") + (match_operand:SI 2 "general_operand" "dKs,dmKs")))] + @dots{}) +@end smallexample + +The first alternative has @samp{m} (memory) for operand 0, @samp{0} for +operand 1 (meaning it must match operand 0), and @samp{dKs} for operand +2. The second alternative has @samp{d} (data register) for operand 0, +@samp{0} for operand 1, and @samp{dmKs} for operand 2. The @samp{=} and +@samp{%} in the constraints apply to all the alternatives; their +meaning is explained in the next section (@pxref{Class Preferences}). +@end ifset + +@c FIXME Is this ? and ! stuff of use in asm()? If not, hide unless INTERNAL +If all the operands fit any one alternative, the instruction is valid. +Otherwise, for each alternative, the compiler counts how many instructions +must be added to copy the operands so that that alternative applies. +The alternative requiring the least copying is chosen. If two alternatives +need the same amount of copying, the one that comes first is chosen. +These choices can be altered with the @samp{?} and @samp{!} characters: + +@table @code +@cindex @samp{?} in constraint +@cindex question mark +@item ? +Disparage slightly the alternative that the @samp{?} appears in, +as a choice when no alternative applies exactly. The compiler regards +this alternative as one unit more costly for each @samp{?} that appears +in it. + +@cindex @samp{!} in constraint +@cindex exclamation point +@item ! +Disparage severely the alternative that the @samp{!} appears in. +This alternative can still be used if it fits without reloading, +but if reloading is needed, some other alternative will be used. +@end table + +@ifset INTERNALS +When an insn pattern has multiple alternatives in its constraints, often +the appearance of the assembler code is determined mostly by which +alternative was matched. When this is so, the C code for writing the +assembler code can use the variable @code{which_alternative}, which is +the ordinal number of the alternative that was actually satisfied (0 for +the first, 1 for the second alternative, etc.). @xref{Output Statement}. +@end ifset + +@ifset INTERNALS +@node Class Preferences +@subsection Register Class Preferences +@cindex class preference constraints +@cindex register class preference constraints + +@cindex voting between constraint alternatives +The operand constraints have another function: they enable the compiler +to decide which kind of hardware register a pseudo register is best +allocated to. The compiler examines the constraints that apply to the +insns that use the pseudo register, looking for the machine-dependent +letters such as @samp{d} and @samp{a} that specify classes of registers. +The pseudo register is put in whichever class gets the most ``votes''. +The constraint letters @samp{g} and @samp{r} also vote: they vote in +favor of a general register. The machine description says which registers +are considered general. + +Of course, on some machines all registers are equivalent, and no register +classes are defined. Then none of this complexity is relevant. +@end ifset + +@node Modifiers +@subsection Constraint Modifier Characters +@cindex modifiers in constraints +@cindex constraint modifier characters + +@c prevent bad page break with this line +Here are constraint modifier characters. + +@table @samp +@cindex @samp{=} in constraint +@item = +Means that this operand is write-only for this instruction: the previous +value is discarded and replaced by output data. + +@cindex @samp{+} in constraint +@item + +Means that this operand is both read and written by the instruction. + +When the compiler fixes up the operands to satisfy the constraints, +it needs to know which operands are inputs to the instruction and +which are outputs from it. @samp{=} identifies an output; @samp{+} +identifies an operand that is both input and output; all other operands +are assumed to be input only. + +If you specify @samp{=} or @samp{+} in a constraint, you put it in the +first character of the constraint string. + +@cindex @samp{&} in constraint +@cindex earlyclobber operand +@item & +Means (in a particular alternative) that this operand is an +@dfn{earlyclobber} operand, which is modified before the instruction is +finished using the input operands. Therefore, this operand may not lie +in a register that is used as an input operand or as part of any memory +address. + +@samp{&} applies only to the alternative in which it is written. In +constraints with multiple alternatives, sometimes one alternative +requires @samp{&} while others do not. See, for example, the +@samp{movdf} insn of the 68000. + +An input operand can be tied to an earlyclobber operand if its only +use as an input occurs before the early result is written. Adding +alternatives of this form often allows GCC to produce better code +when only some of the inputs can be affected by the earlyclobber. +See, for example, the @samp{mulsi3} insn of the ARM@. + +@samp{&} does not obviate the need to write @samp{=}. + +@cindex @samp{%} in constraint +@item % +Declares the instruction to be commutative for this operand and the +following operand. This means that the compiler may interchange the +two operands if that is the cheapest way to make all operands fit the +constraints. +@ifset INTERNALS +This is often used in patterns for addition instructions +that really have only two operands: the result must go in one of the +arguments. Here for example, is how the 68000 halfword-add +instruction is defined: + +@smallexample +(define_insn "addhi3" + [(set (match_operand:HI 0 "general_operand" "=m,r") + (plus:HI (match_operand:HI 1 "general_operand" "%0,0") + (match_operand:HI 2 "general_operand" "di,g")))] + @dots{}) +@end smallexample +@end ifset +GCC can only handle one commutative pair in an asm; if you use more, +the compiler may fail. Note that you need not use the modifier if +the two alternatives are strictly identical; this would only waste +time in the reload pass. The modifier is not operational after +register allocation, so the result of @code{define_peephole2} +and @code{define_split}s performed after reload cannot rely on +@samp{%} to make the intended insn match. + +@cindex @samp{#} in constraint +@item # +Says that all following characters, up to the next comma, are to be +ignored as a constraint. They are significant only for choosing +register preferences. + +@cindex @samp{*} in constraint +@item * +Says that the following character should be ignored when choosing +register preferences. @samp{*} has no effect on the meaning of the +constraint as a constraint, and no effect on reloading. + +@ifset INTERNALS +Here is an example: the 68000 has an instruction to sign-extend a +halfword in a data register, and can also sign-extend a value by +copying it into an address register. While either kind of register is +acceptable, the constraints on an address-register destination are +less strict, so it is best if register allocation makes an address +register its goal. Therefore, @samp{*} is used so that the @samp{d} +constraint letter (for data register) is ignored when computing +register preferences. + +@smallexample +(define_insn "extendhisi2" + [(set (match_operand:SI 0 "general_operand" "=*d,a") + (sign_extend:SI + (match_operand:HI 1 "general_operand" "0,g")))] + @dots{}) +@end smallexample +@end ifset +@end table + +@node Machine Constraints +@subsection Constraints for Particular Machines +@cindex machine specific constraints +@cindex constraints, machine specific + +Whenever possible, you should use the general-purpose constraint letters +in @code{asm} arguments, since they will convey meaning more readily to +people reading your code. Failing that, use the constraint letters +that usually have very similar meanings across architectures. The most +commonly used constraints are @samp{m} and @samp{r} (for memory and +general-purpose registers respectively; @pxref{Simple Constraints}), and +@samp{I}, usually the letter indicating the most common +immediate-constant format. + +Each architecture defines additional constraints. These constraints +are used by the compiler itself for instruction generation, as well as +for @code{asm} statements; therefore, some of the constraints are not +particularly useful for @code{asm}. Here is a summary of some of the +machine-dependent constraints available on some particular machines; +it includes both constraints that are useful for @code{asm} and +constraints that aren't. The compiler source file mentioned in the +table heading for each architecture is the definitive reference for +the meanings of that architecture's constraints. + +@table @emph +@item ARM family---@file{config/arm/arm.h} +@table @code +@item f +Floating-point register + +@item w +VFP floating-point register + +@item F +One of the floating-point constants 0.0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 +or 10.0 + +@item G +Floating-point constant that would satisfy the constraint @samp{F} if it +were negated + +@item I +Integer that is valid as an immediate operand in a data processing +instruction. That is, an integer in the range 0 to 255 rotated by a +multiple of 2 + +@item J +Integer in the range @minus{}4095 to 4095 + +@item K +Integer that satisfies constraint @samp{I} when inverted (ones complement) + +@item L +Integer that satisfies constraint @samp{I} when negated (twos complement) + +@item M +Integer in the range 0 to 32 + +@item Q +A memory reference where the exact address is in a single register +(`@samp{m}' is preferable for @code{asm} statements) + +@item R +An item in the constant pool + +@item S +A symbol in the text segment of the current file + +@item Uv +A memory reference suitable for VFP load/store insns (reg+constant offset) + +@item Uy +A memory reference suitable for iWMMXt load/store instructions. + +@item Uq +A memory reference suitable for the ARMv4 ldrsb instruction. +@end table + +@item AVR family---@file{config/avr/constraints.md} +@table @code +@item l +Registers from r0 to r15 + +@item a +Registers from r16 to r23 + +@item d +Registers from r16 to r31 + +@item w +Registers from r24 to r31. These registers can be used in @samp{adiw} command + +@item e +Pointer register (r26--r31) + +@item b +Base pointer register (r28--r31) + +@item q +Stack pointer register (SPH:SPL) + +@item t +Temporary register r0 + +@item x +Register pair X (r27:r26) + +@item y +Register pair Y (r29:r28) + +@item z +Register pair Z (r31:r30) + +@item I +Constant greater than @minus{}1, less than 64 + +@item J +Constant greater than @minus{}64, less than 1 + +@item K +Constant integer 2 + +@item L +Constant integer 0 + +@item M +Constant that fits in 8 bits + +@item N +Constant integer @minus{}1 + +@item O +Constant integer 8, 16, or 24 + +@item P +Constant integer 1 + +@item G +A floating point constant 0.0 +@end table + +@item CRX Architecture---@file{config/crx/crx.h} +@table @code + +@item b +Registers from r0 to r14 (registers without stack pointer) + +@item l +Register r16 (64-bit accumulator lo register) + +@item h +Register r17 (64-bit accumulator hi register) + +@item k +Register pair r16-r17. (64-bit accumulator lo-hi pair) + +@item I +Constant that fits in 3 bits + +@item J +Constant that fits in 4 bits + +@item K +Constant that fits in 5 bits + +@item L +Constant that is one of -1, 4, -4, 7, 8, 12, 16, 20, 32, 48 + +@item G +Floating point constant that is legal for store immediate +@end table + +@item PowerPC and IBM RS6000---@file{config/rs6000/rs6000.h} +@table @code +@item b +Address base register + +@item f +Floating point register + +@item v +Vector register + +@item h +@samp{MQ}, @samp{CTR}, or @samp{LINK} register + +@item q +@samp{MQ} register + +@item c +@samp{CTR} register + +@item l +@samp{LINK} register + +@item x +@samp{CR} register (condition register) number 0 + +@item y +@samp{CR} register (condition register) + +@item z +@samp{FPMEM} stack memory for FPR-GPR transfers + +@item I +Signed 16-bit constant + +@item J +Unsigned 16-bit constant shifted left 16 bits (use @samp{L} instead for +@code{SImode} constants) + +@item K +Unsigned 16-bit constant + +@item L +Signed 16-bit constant shifted left 16 bits + +@item M +Constant larger than 31 + +@item N +Exact power of 2 + +@item O +Zero + +@item P +Constant whose negation is a signed 16-bit constant + +@item G +Floating point constant that can be loaded into a register with one +instruction per word + +@item Q +Memory operand that is an offset from a register (@samp{m} is preferable +for @code{asm} statements) + +@item R +AIX TOC entry + +@item S +Constant suitable as a 64-bit mask operand + +@item T +Constant suitable as a 32-bit mask operand + +@item U +System V Release 4 small data area reference +@end table + +@item MorphoTech family---@file{config/mt/mt.h} +@table @code +@item I +Constant for an arithmetic insn (16-bit signed integer). + +@item J +The constant 0. + +@item K +Constant for a logical insn (16-bit zero-extended integer). + +@item L +A constant that can be loaded with @code{lui} (i.e.@: the bottom 16 +bits are zero). + +@item M +A constant that takes two words to load (i.e.@: not matched by +@code{I}, @code{K}, or @code{L}). + +@item N +Negative 16-bit constants other than -65536. + +@item O +A 15-bit signed integer constant. + +@item P +A positive 16-bit constant. +@end table + +@item Intel 386---@file{config/i386/constraints.md} +@table @code +@item R +Legacy register---the eight integer registers available on all +i386 processors (@code{a}, @code{b}, @code{c}, @code{d}, +@code{si}, @code{di}, @code{bp}, @code{sp}). + +@item q +Any register accessible as @code{@var{r}l}. In 32-bit mode, @code{a}, +@code{b}, @code{c}, and @code{d}; in 64-bit mode, any integer register. + +@item Q +Any register accessible as @code{@var{r}h}: @code{a}, @code{b}, +@code{c}, and @code{d}. + +@ifset INTERNALS +@item l +Any register that can be used as the index in a base+index memory +access: that is, any general register except the stack pointer. +@end ifset + +@item a +The @code{a} register. + +@item b +The @code{b} register. + +@item c +The @code{c} register. + +@item d +The @code{d} register. + +@item S +The @code{si} register. + +@item D +The @code{di} register. + +@item A +The @code{a} and @code{d} registers, as a pair (for instructions that +return half the result in one and half in the other). + +@item f +Any 80387 floating-point (stack) register. + +@item t +Top of 80387 floating-point stack (@code{%st(0)}). + +@item u +Second from top of 80387 floating-point stack (@code{%st(1)}). + +@item y +Any MMX register. + +@item x +Any SSE register. + +@ifset INTERNALS +@item Y +Any SSE2 register. +@end ifset + +@item I +Integer constant in the range 0 @dots{} 31, for 32-bit shifts. + +@item J +Integer constant in the range 0 @dots{} 63, for 64-bit shifts. + +@item K +Signed 8-bit integer constant. + +@item L +@code{0xFF} or @code{0xFFFF}, for andsi as a zero-extending move. + +@item M +0, 1, 2, or 3 (shifts for the @code{lea} instruction). + +@item N +Unsigned 8-bit integer constant (for @code{in} and @code{out} +instructions). + +@ifset INTERNALS +@item O +Integer constant in the range 0 @dots{} 127, for 128-bit shifts. +@end ifset + +@item G +Standard 80387 floating point constant. + +@item C +Standard SSE floating point constant. + +@item e +32-bit signed integer constant, or a symbolic reference known +to fit that range (for immediate operands in sign-extending x86-64 +instructions). + +@item Z +32-bit unsigned integer constant, or a symbolic reference known +to fit that range (for immediate operands in zero-extending x86-64 +instructions). + +@end table + +@item Intel IA-64---@file{config/ia64/ia64.h} +@table @code +@item a +General register @code{r0} to @code{r3} for @code{addl} instruction + +@item b +Branch register + +@item c +Predicate register (@samp{c} as in ``conditional'') + +@item d +Application register residing in M-unit + +@item e +Application register residing in I-unit + +@item f +Floating-point register + +@item m +Memory operand. +Remember that @samp{m} allows postincrement and postdecrement which +require printing with @samp{%Pn} on IA-64. +Use @samp{S} to disallow postincrement and postdecrement. + +@item G +Floating-point constant 0.0 or 1.0 + +@item I +14-bit signed integer constant + +@item J +22-bit signed integer constant + +@item K +8-bit signed integer constant for logical instructions + +@item L +8-bit adjusted signed integer constant for compare pseudo-ops + +@item M +6-bit unsigned integer constant for shift counts + +@item N +9-bit signed integer constant for load and store postincrements + +@item O +The constant zero + +@item P +0 or @minus{}1 for @code{dep} instruction + +@item Q +Non-volatile memory for floating-point loads and stores + +@item R +Integer constant in the range 1 to 4 for @code{shladd} instruction + +@item S +Memory operand except postincrement and postdecrement +@end table + +@item FRV---@file{config/frv/frv.h} +@table @code +@item a +Register in the class @code{ACC_REGS} (@code{acc0} to @code{acc7}). + +@item b +Register in the class @code{EVEN_ACC_REGS} (@code{acc0} to @code{acc7}). + +@item c +Register in the class @code{CC_REGS} (@code{fcc0} to @code{fcc3} and +@code{icc0} to @code{icc3}). + +@item d +Register in the class @code{GPR_REGS} (@code{gr0} to @code{gr63}). + +@item e +Register in the class @code{EVEN_REGS} (@code{gr0} to @code{gr63}). +Odd registers are excluded not in the class but through the use of a machine +mode larger than 4 bytes. + +@item f +Register in the class @code{FPR_REGS} (@code{fr0} to @code{fr63}). + +@item h +Register in the class @code{FEVEN_REGS} (@code{fr0} to @code{fr63}). +Odd registers are excluded not in the class but through the use of a machine +mode larger than 4 bytes. + +@item l +Register in the class @code{LR_REG} (the @code{lr} register). + +@item q +Register in the class @code{QUAD_REGS} (@code{gr2} to @code{gr63}). +Register numbers not divisible by 4 are excluded not in the class but through +the use of a machine mode larger than 8 bytes. + +@item t +Register in the class @code{ICC_REGS} (@code{icc0} to @code{icc3}). + +@item u +Register in the class @code{FCC_REGS} (@code{fcc0} to @code{fcc3}). + +@item v +Register in the class @code{ICR_REGS} (@code{cc4} to @code{cc7}). + +@item w +Register in the class @code{FCR_REGS} (@code{cc0} to @code{cc3}). + +@item x +Register in the class @code{QUAD_FPR_REGS} (@code{fr0} to @code{fr63}). +Register numbers not divisible by 4 are excluded not in the class but through +the use of a machine mode larger than 8 bytes. + +@item z +Register in the class @code{SPR_REGS} (@code{lcr} and @code{lr}). + +@item A +Register in the class @code{QUAD_ACC_REGS} (@code{acc0} to @code{acc7}). + +@item B +Register in the class @code{ACCG_REGS} (@code{accg0} to @code{accg7}). + +@item C +Register in the class @code{CR_REGS} (@code{cc0} to @code{cc7}). + +@item G +Floating point constant zero + +@item I +6-bit signed integer constant + +@item J +10-bit signed integer constant + +@item L +16-bit signed integer constant + +@item M +16-bit unsigned integer constant + +@item N +12-bit signed integer constant that is negative---i.e.@: in the +range of @minus{}2048 to @minus{}1 + +@item O +Constant zero + +@item P +12-bit signed integer constant that is greater than zero---i.e.@: in the +range of 1 to 2047. + +@end table + +@item Blackfin family---@file{config/bfin/bfin.h} +@table @code +@item a +P register + +@item d +D register + +@item z +A call clobbered P register. + +@item D +Even-numbered D register + +@item W +Odd-numbered D register + +@item e +Accumulator register. + +@item A +Even-numbered accumulator register. + +@item B +Odd-numbered accumulator register. + +@item b +I register + +@item v +B register + +@item f +M register + +@item c +Registers used for circular buffering, i.e. I, B, or L registers. + +@item C +The CC register. + +@item t +LT0 or LT1. + +@item k +LC0 or LC1. + +@item u +LB0 or LB1. + +@item x +Any D, P, B, M, I or L register. + +@item y +Additional registers typically used only in prologues and epilogues: RETS, +RETN, RETI, RETX, RETE, ASTAT, SEQSTAT and USP. + +@item w +Any register except accumulators or CC. + +@item Ksh +Signed 16 bit integer (in the range -32768 to 32767) + +@item Kuh +Unsigned 16 bit integer (in the range 0 to 65535) + +@item Ks7 +Signed 7 bit integer (in the range -64 to 63) + +@item Ku7 +Unsigned 7 bit integer (in the range 0 to 127) + +@item Ku5 +Unsigned 5 bit integer (in the range 0 to 31) + +@item Ks4 +Signed 4 bit integer (in the range -8 to 7) + +@item Ks3 +Signed 3 bit integer (in the range -3 to 4) + +@item Ku3 +Unsigned 3 bit integer (in the range 0 to 7) + +@item P@var{n} +Constant @var{n}, where @var{n} is a single-digit constant in the range 0 to 4. + +@item M1 +Constant 255. + +@item M2 +Constant 65535. + +@item J +An integer constant with exactly a single bit set. + +@item L +An integer constant with all bits set except exactly one. + +@item H + +@item Q +Any SYMBOL_REF. +@end table + +@item M32C---@file{config/m32c/m32c.c} +@table @code +@item Rsp +@itemx Rfb +@itemx Rsb +@samp{$sp}, @samp{$fb}, @samp{$sb}. + +@item Rcr +Any control register, when they're 16 bits wide (nothing if control +registers are 24 bits wide) + +@item Rcl +Any control register, when they're 24 bits wide. + +@item R0w +@itemx R1w +@itemx R2w +@itemx R3w +$r0, $r1, $r2, $r3. + +@item R02 +$r0 or $r2, or $r2r0 for 32 bit values. + +@item R13 +$r1 or $r3, or $r3r1 for 32 bit values. + +@item Rdi +A register that can hold a 64 bit value. + +@item Rhl +$r0 or $r1 (registers with addressable high/low bytes) + +@item R23 +$r2 or $r3 + +@item Raa +Address registers + +@item Raw +Address registers when they're 16 bits wide. + +@item Ral +Address registers when they're 24 bits wide. + +@item Rqi +Registers that can hold QI values. + +@item Rad +Registers that can be used with displacements ($a0, $a1, $sb). + +@item Rsi +Registers that can hold 32 bit values. + +@item Rhi +Registers that can hold 16 bit values. + +@item Rhc +Registers chat can hold 16 bit values, including all control +registers. + +@item Rra +$r0 through R1, plus $a0 and $a1. + +@item Rfl +The flags register. + +@item Rmm +The memory-based pseudo-registers $mem0 through $mem15. + +@item Rpi +Registers that can hold pointers (16 bit registers for r8c, m16c; 24 +bit registers for m32cm, m32c). + +@item Rpa +Matches multiple registers in a PARALLEL to form a larger register. +Used to match function return values. + +@item Is3 +-8 @dots{} 7 + +@item IS1 +-128 @dots{} 127 + +@item IS2 +-32768 @dots{} 32767 + +@item IU2 +0 @dots{} 65535 + +@item In4 +-8 @dots{} -1 or 1 @dots{} 8 + +@item In5 +-16 @dots{} -1 or 1 @dots{} 16 + +@item In6 +-32 @dots{} -1 or 1 @dots{} 32 + +@item IM2 +-65536 @dots{} -1 + +@item Ilb +An 8 bit value with exactly one bit set. + +@item Ilw +A 16 bit value with exactly one bit set. + +@item Sd +The common src/dest memory addressing modes. + +@item Sa +Memory addressed using $a0 or $a1. + +@item Si +Memory addressed with immediate addresses. + +@item Ss +Memory addressed using the stack pointer ($sp). + +@item Sf +Memory addressed using the frame base register ($fb). + +@item Ss +Memory addressed using the small base register ($sb). + +@item S1 +$r1h +@end table + +@item MIPS---@file{config/mips/constraints.md} +@table @code +@item d +An address register. This is equivalent to @code{r} unless +generating MIPS16 code. + +@item f +A floating-point register (if available). + +@item h +The @code{hi} register. + +@item l +The @code{lo} register. + +@item x +The @code{hi} and @code{lo} registers. + +@item c +A register suitable for use in an indirect jump. This will always be +@code{$25} for @option{-mabicalls}. + +@item y +Equivalent to @code{r}; retained for backwards compatibility. + +@item z +A floating-point condition code register. + +@item I +A signed 16-bit constant (for arithmetic instructions). + +@item J +Integer zero. + +@item K +An unsigned 16-bit constant (for logic instructions). + +@item L +A signed 32-bit constant in which the lower 16 bits are zero. +Such constants can be loaded using @code{lui}. + +@item M +A constant that cannot be loaded using @code{lui}, @code{addiu} +or @code{ori}. + +@item N +A constant in the range -65535 to -1 (inclusive). + +@item O +A signed 15-bit constant. + +@item P +A constant in the range 1 to 65535 (inclusive). + +@item G +Floating-point zero. + +@item R +An address that can be used in a non-macro load or store. +@end table + +@item Motorola 680x0---@file{config/m68k/m68k.h} +@table @code +@item a +Address register + +@item d +Data register + +@item f +68881 floating-point register, if available + +@item I +Integer in the range 1 to 8 + +@item J +16-bit signed number + +@item K +Signed number whose magnitude is greater than 0x80 + +@item L +Integer in the range @minus{}8 to @minus{}1 + +@item M +Signed number whose magnitude is greater than 0x100 + +@item G +Floating point constant that is not a 68881 constant +@end table + +@item Motorola 68HC11 & 68HC12 families---@file{config/m68hc11/m68hc11.h} +@table @code +@item a +Register `a' + +@item b +Register `b' + +@item d +Register `d' + +@item q +An 8-bit register + +@item t +Temporary soft register _.tmp + +@item u +A soft register _.d1 to _.d31 + +@item w +Stack pointer register + +@item x +Register `x' + +@item y +Register `y' + +@item z +Pseudo register `z' (replaced by `x' or `y' at the end) + +@item A +An address register: x, y or z + +@item B +An address register: x or y + +@item D +Register pair (x:d) to form a 32-bit value + +@item L +Constants in the range @minus{}65536 to 65535 + +@item M +Constants whose 16-bit low part is zero + +@item N +Constant integer 1 or @minus{}1 + +@item O +Constant integer 16 + +@item P +Constants in the range @minus{}8 to 2 + +@end table + +@need 1000 +@item SPARC---@file{config/sparc/sparc.h} +@table @code +@item f +Floating-point register on the SPARC-V8 architecture and +lower floating-point register on the SPARC-V9 architecture. + +@item e +Floating-point register. It is equivalent to @samp{f} on the +SPARC-V8 architecture and contains both lower and upper +floating-point registers on the SPARC-V9 architecture. + +@item c +Floating-point condition code register. + +@item d +Lower floating-point register. It is only valid on the SPARC-V9 +architecture when the Visual Instruction Set is available. + +@item b +Floating-point register. It is only valid on the SPARC-V9 architecture +when the Visual Instruction Set is available. + +@item h +64-bit global or out register for the SPARC-V8+ architecture. + +@item I +Signed 13-bit constant + +@item J +Zero + +@item K +32-bit constant with the low 12 bits clear (a constant that can be +loaded with the @code{sethi} instruction) + +@item L +A constant in the range supported by @code{movcc} instructions + +@item M +A constant in the range supported by @code{movrcc} instructions + +@item N +Same as @samp{K}, except that it verifies that bits that are not in the +lower 32-bit range are all zero. Must be used instead of @samp{K} for +modes wider than @code{SImode} + +@item O +The constant 4096 + +@item G +Floating-point zero + +@item H +Signed 13-bit constant, sign-extended to 32 or 64 bits + +@item Q +Floating-point constant whose integral representation can +be moved into an integer register using a single sethi +instruction + +@item R +Floating-point constant whose integral representation can +be moved into an integer register using a single mov +instruction + +@item S +Floating-point constant whose integral representation can +be moved into an integer register using a high/lo_sum +instruction sequence + +@item T +Memory address aligned to an 8-byte boundary + +@item U +Even register + +@item W +Memory address for @samp{e} constraint registers + +@item Y +Vector zero + +@end table + +@item TMS320C3x/C4x---@file{config/c4x/c4x.h} +@table @code +@item a +Auxiliary (address) register (ar0-ar7) + +@item b +Stack pointer register (sp) + +@item c +Standard (32-bit) precision integer register + +@item f +Extended (40-bit) precision register (r0-r11) + +@item k +Block count register (bk) + +@item q +Extended (40-bit) precision low register (r0-r7) + +@item t +Extended (40-bit) precision register (r0-r1) + +@item u +Extended (40-bit) precision register (r2-r3) + +@item v +Repeat count register (rc) + +@item x +Index register (ir0-ir1) + +@item y +Status (condition code) register (st) + +@item z +Data page register (dp) + +@item G +Floating-point zero + +@item H +Immediate 16-bit floating-point constant + +@item I +Signed 16-bit constant + +@item J +Signed 8-bit constant + +@item K +Signed 5-bit constant + +@item L +Unsigned 16-bit constant + +@item M +Unsigned 8-bit constant + +@item N +Ones complement of unsigned 16-bit constant + +@item O +High 16-bit constant (32-bit constant with 16 LSBs zero) + +@item Q +Indirect memory reference with signed 8-bit or index register displacement + +@item R +Indirect memory reference with unsigned 5-bit displacement + +@item S +Indirect memory reference with 1 bit or index register displacement + +@item T +Direct memory reference + +@item U +Symbolic address + +@end table + +@item S/390 and zSeries---@file{config/s390/s390.h} +@table @code +@item a +Address register (general purpose register except r0) + +@item c +Condition code register + +@item d +Data register (arbitrary general purpose register) + +@item f +Floating-point register + +@item I +Unsigned 8-bit constant (0--255) + +@item J +Unsigned 12-bit constant (0--4095) + +@item K +Signed 16-bit constant (@minus{}32768--32767) + +@item L +Value appropriate as displacement. +@table @code + @item (0..4095) + for short displacement + @item (-524288..524287) + for long displacement +@end table + +@item M +Constant integer with a value of 0x7fffffff. + +@item N +Multiple letter constraint followed by 4 parameter letters. +@table @code + @item 0..9: + number of the part counting from most to least significant + @item H,Q: + mode of the part + @item D,S,H: + mode of the containing operand + @item 0,F: + value of the other parts (F---all bits set) +@end table +The constraint matches if the specified part of a constant +has a value different from it's other parts. + +@item Q +Memory reference without index register and with short displacement. + +@item R +Memory reference with index register and short displacement. + +@item S +Memory reference without index register but with long displacement. + +@item T +Memory reference with index register and long displacement. + +@item U +Pointer with short displacement. + +@item W +Pointer with long displacement. + +@item Y +Shift count operand. + +@end table + +@item Score family---@file{config/score/score.h} +@table @code +@item d +Registers from r0 to r32. + +@item e +Registers from r0 to r16. + +@item t +r8---r11 or r22---r27 registers. + +@item h +hi register. + +@item l +lo register. + +@item x +hi + lo register. + +@item q +cnt register. + +@item y +lcb register. + +@item z +scb register. + +@item a +cnt + lcb + scb register. + +@item c +cr0---cr15 register. + +@item b +cp1 registers. + +@item f +cp2 registers. + +@item i +cp3 registers. + +@item j +cp1 + cp2 + cp3 registers. + +@item I +High 16-bit constant (32-bit constant with 16 LSBs zero). + +@item J +Unsigned 5 bit integer (in the range 0 to 31). + +@item K +Unsigned 16 bit integer (in the range 0 to 65535). + +@item L +Signed 16 bit integer (in the range @minus{}32768 to 32767). + +@item M +Unsigned 14 bit integer (in the range 0 to 16383). + +@item N +Signed 14 bit integer (in the range @minus{}8192 to 8191). + +@item Z +Any SYMBOL_REF. +@end table + +@item Xstormy16---@file{config/stormy16/stormy16.h} +@table @code +@item a +Register r0. + +@item b +Register r1. + +@item c +Register r2. + +@item d +Register r8. + +@item e +Registers r0 through r7. + +@item t +Registers r0 and r1. + +@item y +The carry register. + +@item z +Registers r8 and r9. + +@item I +A constant between 0 and 3 inclusive. + +@item J +A constant that has exactly one bit set. + +@item K +A constant that has exactly one bit clear. + +@item L +A constant between 0 and 255 inclusive. + +@item M +A constant between @minus{}255 and 0 inclusive. + +@item N +A constant between @minus{}3 and 0 inclusive. + +@item O +A constant between 1 and 4 inclusive. + +@item P +A constant between @minus{}4 and @minus{}1 inclusive. + +@item Q +A memory reference that is a stack push. + +@item R +A memory reference that is a stack pop. + +@item S +A memory reference that refers to a constant address of known value. + +@item T +The register indicated by Rx (not implemented yet). + +@item U +A constant that is not between 2 and 15 inclusive. + +@item Z +The constant 0. + +@end table + +@item Xtensa---@file{config/xtensa/xtensa.h} +@table @code +@item a +General-purpose 32-bit register + +@item b +One-bit boolean register + +@item A +MAC16 40-bit accumulator register + +@item I +Signed 12-bit integer constant, for use in MOVI instructions + +@item J +Signed 8-bit integer constant, for use in ADDI instructions + +@item K +Integer constant valid for BccI instructions + +@item L +Unsigned constant valid for BccUI instructions + +@end table + +@end table + +@ifset INTERNALS +@node Define Constraints +@subsection Defining Machine-Specific Constraints +@cindex defining constraints +@cindex constraints, defining + +Machine-specific constraints fall into two categories: register and +non-register constraints. Within the latter category, constraints +which allow subsets of all possible memory or address operands should +be specially marked, to give @code{reload} more information. + +Machine-specific constraints can be given names of arbitrary length, +but they must be entirely composed of letters, digits, underscores +(@samp{_}), and angle brackets (@samp{< >}). Like C identifiers, they +must begin with a letter or underscore. + +In order to avoid ambiguity in operand constraint strings, no +constraint can have a name that begins with any other constraint's +name. For example, if @code{x} is defined as a constraint name, +@code{xy} may not be, and vice versa. As a consequence of this rule, +no constraint may begin with one of the generic constraint letters: +@samp{E F V X g i m n o p r s}. + +Register constraints correspond directly to register classes. +@xref{Register Classes}. There is thus not much flexibility in their +definitions. + +@deffn {MD Expression} define_register_constraint name regclass docstring +All three arguments are string constants. +@var{name} is the name of the constraint, as it will appear in +@code{match_operand} expressions. @var{regclass} can be either the +name of the corresponding register class (@pxref{Register Classes}), +or a C expression which evaluates to the appropriate register class. +If it is an expression, it must have no side effects, and it cannot +look at the operand. The usual use of expressions is to map some +register constraints to @code{NO_REGS} when the register class +is not available on a given subarchitecture. + +@var{docstring} is a sentence documenting the meaning of the +constraint. Docstrings are explained further below. +@end deffn + +Non-register constraints are more like predicates: the constraint +definition gives a Boolean expression which indicates whether the +constraint matches. + +@deffn {MD Expression} define_constraint name docstring exp +The @var{name} and @var{docstring} arguments are the same as for +@code{define_register_constraint}, but note that the docstring comes +immediately after the name for these expressions. @var{exp} is an RTL +expression, obeying the same rules as the RTL expressions in predicate +definitions. @xref{Defining Predicates}, for details. If it +evaluates true, the constraint matches; if it evaluates false, it +doesn't. Constraint expressions should indicate which RTL codes they +might match, just like predicate expressions. + +@code{match_test} C expressions have access to the +following variables: + +@table @var +@item op +The RTL object defining the operand. +@item mode +The machine mode of @var{op}. +@item ival +@samp{INTVAL (@var{op})}, if @var{op} is a @code{const_int}. +@item hval +@samp{CONST_DOUBLE_HIGH (@var{op})}, if @var{op} is an integer +@code{const_double}. +@item lval +@samp{CONST_DOUBLE_LOW (@var{op})}, if @var{op} is an integer +@code{const_double}. +@item rval +@samp{CONST_DOUBLE_REAL_VALUE (@var{op})}, if @var{op} is a floating-point +@code{const_double}. +@end table + +The @var{*val} variables should only be used once another piece of the +expression has verified that @var{op} is the appropriate kind of RTL +object. +@end deffn + +Most non-register constraints should be defined with +@code{define_constraint}. The remaining two definition expressions +are only appropriate for constraints that should be handled specially +by @code{reload} if they fail to match. + +@deffn {MD Expression} define_memory_constraint name docstring exp +Use this expression for constraints that match a subset of all memory +operands: that is, @code{reload} can make them match by converting the +operand to the form @samp{@w{(mem (reg @var{X}))}}, where @var{X} is a +base register (from the register class specified by +@code{BASE_REG_CLASS}, @pxref{Register Classes}). + +For example, on the S/390, some instructions do not accept arbitrary +memory references, but only those that do not make use of an index +register. The constraint letter @samp{Q} is defined to represent a +memory address of this type. If @samp{Q} is defined with +@code{define_memory_constraint}, a @samp{Q} constraint can handle any +memory operand, because @code{reload} knows it can simply copy the +memory address into a base register if required. This is analogous to +the way a @samp{o} constraint can handle any memory operand. + +The syntax and semantics are otherwise identical to +@code{define_constraint}. +@end deffn + +@deffn {MD Expression} define_address_constraint name docstring exp +Use this expression for constraints that match a subset of all address +operands: that is, @code{reload} can make the constraint match by +converting the operand to the form @samp{@w{(reg @var{X})}}, again +with @var{X} a base register. + +Constraints defined with @code{define_address_constraint} can only be +used with the @code{address_operand} predicate, or machine-specific +predicates that work the same way. They are treated analogously to +the generic @samp{p} constraint. + +The syntax and semantics are otherwise identical to +@code{define_constraint}. +@end deffn + +For historical reasons, names beginning with the letters @samp{G H} +are reserved for constraints that match only @code{const_double}s, and +names beginning with the letters @samp{I J K L M N O P} are reserved +for constraints that match only @code{const_int}s. This may change in +the future. For the time being, constraints with these names must be +written in a stylized form, so that @code{genpreds} can tell you did +it correctly: + +@smallexample +@group +(define_constraint "[@var{GHIJKLMNOP}]@dots{}" + "@var{doc}@dots{}" + (and (match_code "const_int") ; @r{@code{const_double} for G/H} + @var{condition}@dots{})) ; @r{usually a @code{match_test}} +@end group +@end smallexample +@c the semicolons line up in the formatted manual + +It is fine to use names beginning with other letters for constraints +that match @code{const_double}s or @code{const_int}s. + +Each docstring in a constraint definition should be one or more complete +sentences, marked up in Texinfo format. @emph{They are currently unused.} +In the future they will be copied into the GCC manual, in @ref{Machine +Constraints}, replacing the hand-maintained tables currently found in +that section. Also, in the future the compiler may use this to give +more helpful diagnostics when poor choice of @code{asm} constraints +causes a reload failure. + +If you put the pseudo-Texinfo directive @samp{@@internal} at the +beginning of a docstring, then (in the future) it will appear only in +the internals manual's version of the machine-specific constraint tables. +Use this for constraints that should not appear in @code{asm} statements. + +@node C Constraint Interface +@subsection Testing constraints from C +@cindex testing constraints +@cindex constraints, testing + +It is occasionally useful to test a constraint from C code rather than +implicitly via the constraint string in a @code{match_operand}. The +generated file @file{tm_p.h} declares a few interfaces for working +with machine-specific constraints. None of these interfaces work with +the generic constraints described in @ref{Simple Constraints}. This +may change in the future. + +@strong{Warning:} @file{tm_p.h} may declare other functions that +operate on constraints, besides the ones documented here. Do not use +those functions from machine-dependent code. They exist to implement +the old constraint interface that machine-independent components of +the compiler still expect. They will change or disappear in the +future. + +Some valid constraint names are not valid C identifiers, so there is a +mangling scheme for referring to them from C@. Constraint names that +do not contain angle brackets or underscores are left unchanged. +Underscores are doubled, each @samp{<} is replaced with @samp{_l}, and +each @samp{>} with @samp{_g}. Here are some examples: + +@c the @c's prevent double blank lines in the printed manual. +@example +@multitable {Original} {Mangled} +@item @strong{Original} @tab @strong{Mangled} @c +@item @code{x} @tab @code{x} @c +@item @code{P42x} @tab @code{P42x} @c +@item @code{P4_x} @tab @code{P4__x} @c +@item @code{P4>x} @tab @code{P4_gx} @c +@item @code{P4>>} @tab @code{P4_g_g} @c +@item @code{P4_g>} @tab @code{P4__g_g} @c +@end multitable +@end example + +Throughout this section, the variable @var{c} is either a constraint +in the abstract sense, or a constant from @code{enum constraint_num}; +the variable @var{m} is a mangled constraint name (usually as part of +a larger identifier). + +@deftp Enum constraint_num +For each machine-specific constraint, there is a corresponding +enumeration constant: @samp{CONSTRAINT_} plus the mangled name of the +constraint. Functions that take an @code{enum constraint_num} as an +argument expect one of these constants. + +Machine-independent constraints do not have associated constants. +This may change in the future. +@end deftp + +@deftypefun {inline bool} satisfies_constraint_@var{m} (rtx @var{exp}) +For each machine-specific, non-register constraint @var{m}, there is +one of these functions; it returns @code{true} if @var{exp} satisfies the +constraint. These functions are only visible if @file{rtl.h} was included +before @file{tm_p.h}. +@end deftypefun + +@deftypefun bool constraint_satisfied_p (rtx @var{exp}, enum constraint_num @var{c}) +Like the @code{satisfies_constraint_@var{m}} functions, but the +constraint to test is given as an argument, @var{c}. If @var{c} +specifies a register constraint, this function will always return +@code{false}. +@end deftypefun + +@deftypefun {enum reg_class} regclass_for_constraint (enum constraint_num @var{c}) +Returns the register class associated with @var{c}. If @var{c} is not +a register constraint, or those registers are not available for the +currently selected subtarget, returns @code{NO_REGS}. +@end deftypefun + +Here is an example use of @code{satisfies_constraint_@var{m}}. In +peephole optimizations (@pxref{Peephole Definitions}), operand +constraint strings are ignored, so if there are relevant constraints, +they must be tested in the C condition. In the example, the +optimization is applied if operand 2 does @emph{not} satisfy the +@samp{K} constraint. (This is a simplified version of a peephole +definition from the i386 machine description.) + +@smallexample +(define_peephole2 + [(match_scratch:SI 3 "r") + (set (match_operand:SI 0 "register_operand" "") + (mult:SI (match_operand:SI 1 "memory_operand" "") + (match_operand:SI 2 "immediate_operand" "")))] + + "!satisfies_constraint_K (operands[2])" + + [(set (match_dup 3) (match_dup 1)) + (set (match_dup 0) (mult:SI (match_dup 3) (match_dup 2)))] + + "") +@end smallexample + +@node Standard Names +@section Standard Pattern Names For Generation +@cindex standard pattern names +@cindex pattern names +@cindex names, pattern + +Here is a table of the instruction names that are meaningful in the RTL +generation pass of the compiler. Giving one of these names to an +instruction pattern tells the RTL generation pass that it can use the +pattern to accomplish a certain task. + +@table @asis +@cindex @code{mov@var{m}} instruction pattern +@item @samp{mov@var{m}} +Here @var{m} stands for a two-letter machine mode name, in lowercase. +This instruction pattern moves data with that machine mode from operand +1 to operand 0. For example, @samp{movsi} moves full-word data. + +If operand 0 is a @code{subreg} with mode @var{m} of a register whose +own mode is wider than @var{m}, the effect of this instruction is +to store the specified value in the part of the register that corresponds +to mode @var{m}. Bits outside of @var{m}, but which are within the +same target word as the @code{subreg} are undefined. Bits which are +outside the target word are left unchanged. + +This class of patterns is special in several ways. First of all, each +of these names up to and including full word size @emph{must} be defined, +because there is no other way to copy a datum from one place to another. +If there are patterns accepting operands in larger modes, +@samp{mov@var{m}} must be defined for integer modes of those sizes. + +Second, these patterns are not used solely in the RTL generation pass. +Even the reload pass can generate move insns to copy values from stack +slots into temporary registers. When it does so, one of the operands is +a hard register and the other is an operand that can need to be reloaded +into a register. + +@findex force_reg +Therefore, when given such a pair of operands, the pattern must generate +RTL which needs no reloading and needs no temporary registers---no +registers other than the operands. For example, if you support the +pattern with a @code{define_expand}, then in such a case the +@code{define_expand} mustn't call @code{force_reg} or any other such +function which might generate new pseudo registers. + +This requirement exists even for subword modes on a RISC machine where +fetching those modes from memory normally requires several insns and +some temporary registers. + +@findex change_address +During reload a memory reference with an invalid address may be passed +as an operand. Such an address will be replaced with a valid address +later in the reload pass. In this case, nothing may be done with the +address except to use it as it stands. If it is copied, it will not be +replaced with a valid address. No attempt should be made to make such +an address into a valid address and no routine (such as +@code{change_address}) that will do so may be called. Note that +@code{general_operand} will fail when applied to such an address. + +@findex reload_in_progress +The global variable @code{reload_in_progress} (which must be explicitly +declared if required) can be used to determine whether such special +handling is required. + +The variety of operands that have reloads depends on the rest of the +machine description, but typically on a RISC machine these can only be +pseudo registers that did not get hard registers, while on other +machines explicit memory references will get optional reloads. + +If a scratch register is required to move an object to or from memory, +it can be allocated using @code{gen_reg_rtx} prior to life analysis. + +If there are cases which need scratch registers during or after reload, +you must provide an appropriate secondary_reload target hook. + +@findex no_new_pseudos +The global variable @code{no_new_pseudos} can be used to determine if it +is unsafe to create new pseudo registers. If this variable is nonzero, then +it is unsafe to call @code{gen_reg_rtx} to allocate a new pseudo. + +The constraints on a @samp{mov@var{m}} must permit moving any hard +register to any other hard register provided that +@code{HARD_REGNO_MODE_OK} permits mode @var{m} in both registers and +@code{REGISTER_MOVE_COST} applied to their classes returns a value of 2. + +It is obligatory to support floating point @samp{mov@var{m}} +instructions into and out of any registers that can hold fixed point +values, because unions and structures (which have modes @code{SImode} or +@code{DImode}) can be in those registers and they may have floating +point members. + +There may also be a need to support fixed point @samp{mov@var{m}} +instructions in and out of floating point registers. Unfortunately, I +have forgotten why this was so, and I don't know whether it is still +true. If @code{HARD_REGNO_MODE_OK} rejects fixed point values in +floating point registers, then the constraints of the fixed point +@samp{mov@var{m}} instructions must be designed to avoid ever trying to +reload into a floating point register. + +@cindex @code{reload_in} instruction pattern +@cindex @code{reload_out} instruction pattern +@item @samp{reload_in@var{m}} +@itemx @samp{reload_out@var{m}} +These named patterns have been obsoleted by the target hook +@code{secondary_reload}. + +Like @samp{mov@var{m}}, but used when a scratch register is required to +move between operand 0 and operand 1. Operand 2 describes the scratch +register. See the discussion of the @code{SECONDARY_RELOAD_CLASS} +macro in @pxref{Register Classes}. + +There are special restrictions on the form of the @code{match_operand}s +used in these patterns. First, only the predicate for the reload +operand is examined, i.e., @code{reload_in} examines operand 1, but not +the predicates for operand 0 or 2. Second, there may be only one +alternative in the constraints. Third, only a single register class +letter may be used for the constraint; subsequent constraint letters +are ignored. As a special exception, an empty constraint string +matches the @code{ALL_REGS} register class. This may relieve ports +of the burden of defining an @code{ALL_REGS} constraint letter just +for these patterns. + +@cindex @code{movstrict@var{m}} instruction pattern +@item @samp{movstrict@var{m}} +Like @samp{mov@var{m}} except that if operand 0 is a @code{subreg} +with mode @var{m} of a register whose natural mode is wider, +the @samp{movstrict@var{m}} instruction is guaranteed not to alter +any of the register except the part which belongs to mode @var{m}. + +@cindex @code{movmisalign@var{m}} instruction pattern +@item @samp{movmisalign@var{m}} +This variant of a move pattern is designed to load or store a value +from a memory address that is not naturally aligned for its mode. +For a store, the memory will be in operand 0; for a load, the memory +will be in operand 1. The other operand is guaranteed not to be a +memory, so that it's easy to tell whether this is a load or store. + +This pattern is used by the autovectorizer, and when expanding a +@code{MISALIGNED_INDIRECT_REF} expression. + +@cindex @code{load_multiple} instruction pattern +@item @samp{load_multiple} +Load several consecutive memory locations into consecutive registers. +Operand 0 is the first of the consecutive registers, operand 1 +is the first memory location, and operand 2 is a constant: the +number of consecutive registers. + +Define this only if the target machine really has such an instruction; +do not define this if the most efficient way of loading consecutive +registers from memory is to do them one at a time. + +On some machines, there are restrictions as to which consecutive +registers can be stored into memory, such as particular starting or +ending register numbers or only a range of valid counts. For those +machines, use a @code{define_expand} (@pxref{Expander Definitions}) +and make the pattern fail if the restrictions are not met. + +Write the generated insn as a @code{parallel} with elements being a +@code{set} of one register from the appropriate memory location (you may +also need @code{use} or @code{clobber} elements). Use a +@code{match_parallel} (@pxref{RTL Template}) to recognize the insn. See +@file{rs6000.md} for examples of the use of this insn pattern. + +@cindex @samp{store_multiple} instruction pattern +@item @samp{store_multiple} +Similar to @samp{load_multiple}, but store several consecutive registers +into consecutive memory locations. Operand 0 is the first of the +consecutive memory locations, operand 1 is the first register, and +operand 2 is a constant: the number of consecutive registers. + +@cindex @code{vec_set@var{m}} instruction pattern +@item @samp{vec_set@var{m}} +Set given field in the vector value. Operand 0 is the vector to modify, +operand 1 is new value of field and operand 2 specify the field index. + +@cindex @code{vec_extract@var{m}} instruction pattern +@item @samp{vec_extract@var{m}} +Extract given field from the vector value. Operand 1 is the vector, operand 2 +specify field index and operand 0 place to store value into. + +@cindex @code{vec_init@var{m}} instruction pattern +@item @samp{vec_init@var{m}} +Initialize the vector to given values. Operand 0 is the vector to initialize +and operand 1 is parallel containing values for individual fields. + +@cindex @code{push@var{m}1} instruction pattern +@item @samp{push@var{m}1} +Output a push instruction. Operand 0 is value to push. Used only when +@code{PUSH_ROUNDING} is defined. For historical reason, this pattern may be +missing and in such case an @code{mov} expander is used instead, with a +@code{MEM} expression forming the push operation. The @code{mov} expander +method is deprecated. + +@cindex @code{add@var{m}3} instruction pattern +@item @samp{add@var{m}3} +Add operand 2 and operand 1, storing the result in operand 0. All operands +must have mode @var{m}. This can be used even on two-address machines, by +means of constraints requiring operands 1 and 0 to be the same location. + +@cindex @code{sub@var{m}3} instruction pattern +@cindex @code{mul@var{m}3} instruction pattern +@cindex @code{div@var{m}3} instruction pattern +@cindex @code{udiv@var{m}3} instruction pattern +@cindex @code{mod@var{m}3} instruction pattern +@cindex @code{umod@var{m}3} instruction pattern +@cindex @code{umin@var{m}3} instruction pattern +@cindex @code{umax@var{m}3} instruction pattern +@cindex @code{and@var{m}3} instruction pattern +@cindex @code{ior@var{m}3} instruction pattern +@cindex @code{xor@var{m}3} instruction pattern +@item @samp{sub@var{m}3}, @samp{mul@var{m}3} +@itemx @samp{div@var{m}3}, @samp{udiv@var{m}3} +@itemx @samp{mod@var{m}3}, @samp{umod@var{m}3} +@itemx @samp{umin@var{m}3}, @samp{umax@var{m}3} +@itemx @samp{and@var{m}3}, @samp{ior@var{m}3}, @samp{xor@var{m}3} +Similar, for other arithmetic operations. + +@cindex @code{min@var{m}3} instruction pattern +@cindex @code{max@var{m}3} instruction pattern +@item @samp{smin@var{m}3}, @samp{smax@var{m}3} +Signed minimum and maximum operations. When used with floating point, +if both operands are zeros, or if either operand is @code{NaN}, then +it is unspecified which of the two operands is returned as the result. + +@cindex @code{reduc_smin_@var{m}} instruction pattern +@cindex @code{reduc_smax_@var{m}} instruction pattern +@item @samp{reduc_smin_@var{m}}, @samp{reduc_smax_@var{m}} +Find the signed minimum/maximum of the elements of a vector. The vector is +operand 1, and the scalar result is stored in the least significant bits of +operand 0 (also a vector). The output and input vector should have the same +modes. + +@cindex @code{reduc_umin_@var{m}} instruction pattern +@cindex @code{reduc_umax_@var{m}} instruction pattern +@item @samp{reduc_umin_@var{m}}, @samp{reduc_umax_@var{m}} +Find the unsigned minimum/maximum of the elements of a vector. The vector is +operand 1, and the scalar result is stored in the least significant bits of +operand 0 (also a vector). The output and input vector should have the same +modes. + +@cindex @code{reduc_splus_@var{m}} instruction pattern +@item @samp{reduc_splus_@var{m}} +Compute the sum of the signed elements of a vector. The vector is operand 1, +and the scalar result is stored in the least significant bits of operand 0 +(also a vector). The output and input vector should have the same modes. + +@cindex @code{reduc_uplus_@var{m}} instruction pattern +@item @samp{reduc_uplus_@var{m}} +Compute the sum of the unsigned elements of a vector. The vector is operand 1, +and the scalar result is stored in the least significant bits of operand 0 +(also a vector). The output and input vector should have the same modes. + +@cindex @code{sdot_prod@var{m}} instruction pattern +@item @samp{sdot_prod@var{m}} +@cindex @code{udot_prod@var{m}} instruction pattern +@item @samp{udot_prod@var{m}} +Compute the sum of the products of two signed/unsigned elements. +Operand 1 and operand 2 are of the same mode. Their product, which is of a +wider mode, is computed and added to operand 3. Operand 3 is of a mode equal or +wider than the mode of the product. The result is placed in operand 0, which +is of the same mode as operand 3. + +@cindex @code{ssum_widen@var{m3}} instruction pattern +@item @samp{ssum_widen@var{m3}} +@cindex @code{usum_widen@var{m3}} instruction pattern +@item @samp{usum_widen@var{m3}} +Operands 0 and 2 are of the same mode, which is wider than the mode of +operand 1. Add operand 1 to operand 2 and place the widened result in +operand 0. (This is used express accumulation of elements into an accumulator +of a wider mode.) + +@cindex @code{vec_shl_@var{m}} instruction pattern +@cindex @code{vec_shr_@var{m}} instruction pattern +@item @samp{vec_shl_@var{m}}, @samp{vec_shr_@var{m}} +Whole vector left/right shift in bits. +Operand 1 is a vector to be shifted. +Operand 2 is an integer shift amount in bits. +Operand 0 is where the resulting shifted vector is stored. +The output and input vectors should have the same modes. + +@cindex @code{mulhisi3} instruction pattern +@item @samp{mulhisi3} +Multiply operands 1 and 2, which have mode @code{HImode}, and store +a @code{SImode} product in operand 0. + +@cindex @code{mulqihi3} instruction pattern +@cindex @code{mulsidi3} instruction pattern +@item @samp{mulqihi3}, @samp{mulsidi3} +Similar widening-multiplication instructions of other widths. + +@cindex @code{umulqihi3} instruction pattern +@cindex @code{umulhisi3} instruction pattern +@cindex @code{umulsidi3} instruction pattern +@item @samp{umulqihi3}, @samp{umulhisi3}, @samp{umulsidi3} +Similar widening-multiplication instructions that do unsigned +multiplication. + +@cindex @code{usmulqihi3} instruction pattern +@cindex @code{usmulhisi3} instruction pattern +@cindex @code{usmulsidi3} instruction pattern +@item @samp{usmulqihi3}, @samp{usmulhisi3}, @samp{usmulsidi3} +Similar widening-multiplication instructions that interpret the first +operand as unsigned and the second operand as signed, then do a signed +multiplication. + +@cindex @code{smul@var{m}3_highpart} instruction pattern +@item @samp{smul@var{m}3_highpart} +Perform a signed multiplication of operands 1 and 2, which have mode +@var{m}, and store the most significant half of the product in operand 0. +The least significant half of the product is discarded. + +@cindex @code{umul@var{m}3_highpart} instruction pattern +@item @samp{umul@var{m}3_highpart} +Similar, but the multiplication is unsigned. + +@cindex @code{divmod@var{m}4} instruction pattern +@item @samp{divmod@var{m}4} +Signed division that produces both a quotient and a remainder. +Operand 1 is divided by operand 2 to produce a quotient stored +in operand 0 and a remainder stored in operand 3. + +For machines with an instruction that produces both a quotient and a +remainder, provide a pattern for @samp{divmod@var{m}4} but do not +provide patterns for @samp{div@var{m}3} and @samp{mod@var{m}3}. This +allows optimization in the relatively common case when both the quotient +and remainder are computed. + +If an instruction that just produces a quotient or just a remainder +exists and is more efficient than the instruction that produces both, +write the output routine of @samp{divmod@var{m}4} to call +@code{find_reg_note} and look for a @code{REG_UNUSED} note on the +quotient or remainder and generate the appropriate instruction. + +@cindex @code{udivmod@var{m}4} instruction pattern +@item @samp{udivmod@var{m}4} +Similar, but does unsigned division. + +@anchor{shift patterns} +@cindex @code{ashl@var{m}3} instruction pattern +@item @samp{ashl@var{m}3} +Arithmetic-shift operand 1 left by a number of bits specified by operand +2, and store the result in operand 0. Here @var{m} is the mode of +operand 0 and operand 1; operand 2's mode is specified by the +instruction pattern, and the compiler will convert the operand to that +mode before generating the instruction. The meaning of out-of-range shift +counts can optionally be specified by @code{TARGET_SHIFT_TRUNCATION_MASK}. +@xref{TARGET_SHIFT_TRUNCATION_MASK}. + +@cindex @code{ashr@var{m}3} instruction pattern +@cindex @code{lshr@var{m}3} instruction pattern +@cindex @code{rotl@var{m}3} instruction pattern +@cindex @code{rotr@var{m}3} instruction pattern +@item @samp{ashr@var{m}3}, @samp{lshr@var{m}3}, @samp{rotl@var{m}3}, @samp{rotr@var{m}3} +Other shift and rotate instructions, analogous to the +@code{ashl@var{m}3} instructions. + +@cindex @code{neg@var{m}2} instruction pattern +@item @samp{neg@var{m}2} +Negate operand 1 and store the result in operand 0. + +@cindex @code{abs@var{m}2} instruction pattern +@item @samp{abs@var{m}2} +Store the absolute value of operand 1 into operand 0. + +@cindex @code{sqrt@var{m}2} instruction pattern +@item @samp{sqrt@var{m}2} +Store the square root of operand 1 into operand 0. + +The @code{sqrt} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{sqrtf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{cos@var{m}2} instruction pattern +@item @samp{cos@var{m}2} +Store the cosine of operand 1 into operand 0. + +The @code{cos} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{cosf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{sin@var{m}2} instruction pattern +@item @samp{sin@var{m}2} +Store the sine of operand 1 into operand 0. + +The @code{sin} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{sinf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{exp@var{m}2} instruction pattern +@item @samp{exp@var{m}2} +Store the exponential of operand 1 into operand 0. + +The @code{exp} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{expf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{log@var{m}2} instruction pattern +@item @samp{log@var{m}2} +Store the natural logarithm of operand 1 into operand 0. + +The @code{log} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{logf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{pow@var{m}3} instruction pattern +@item @samp{pow@var{m}3} +Store the value of operand 1 raised to the exponent operand 2 +into operand 0. + +The @code{pow} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{powf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{atan2@var{m}3} instruction pattern +@item @samp{atan2@var{m}3} +Store the arc tangent (inverse tangent) of operand 1 divided by +operand 2 into operand 0, using the signs of both arguments to +determine the quadrant of the result. + +The @code{atan2} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{atan2f} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{floor@var{m}2} instruction pattern +@item @samp{floor@var{m}2} +Store the largest integral value not greater than argument. + +The @code{floor} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{floorf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{btrunc@var{m}2} instruction pattern +@item @samp{btrunc@var{m}2} +Store the argument rounded to integer towards zero. + +The @code{trunc} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{truncf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{round@var{m}2} instruction pattern +@item @samp{round@var{m}2} +Store the argument rounded to integer away from zero. + +The @code{round} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{roundf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{ceil@var{m}2} instruction pattern +@item @samp{ceil@var{m}2} +Store the argument rounded to integer away from zero. + +The @code{ceil} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{ceilf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{nearbyint@var{m}2} instruction pattern +@item @samp{nearbyint@var{m}2} +Store the argument rounded according to the default rounding mode + +The @code{nearbyint} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{nearbyintf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{rint@var{m}2} instruction pattern +@item @samp{rint@var{m}2} +Store the argument rounded according to the default rounding mode and +raise the inexact exception when the result differs in value from +the argument + +The @code{rint} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{rintf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{copysign@var{m}3} instruction pattern +@item @samp{copysign@var{m}3} +Store a value with the magnitude of operand 1 and the sign of operand +2 into operand 0. + +The @code{copysign} built-in function of C always uses the mode which +corresponds to the C data type @code{double} and the @code{copysignf} +built-in function uses the mode which corresponds to the C data +type @code{float}. + +@cindex @code{ffs@var{m}2} instruction pattern +@item @samp{ffs@var{m}2} +Store into operand 0 one plus the index of the least significant 1-bit +of operand 1. If operand 1 is zero, store zero. @var{m} is the mode +of operand 0; operand 1's mode is specified by the instruction +pattern, and the compiler will convert the operand to that mode before +generating the instruction. + +The @code{ffs} built-in function of C always uses the mode which +corresponds to the C data type @code{int}. + +@cindex @code{clz@var{m}2} instruction pattern +@item @samp{clz@var{m}2} +Store into operand 0 the number of leading 0-bits in @var{x}, starting +at the most significant bit position. If @var{x} is 0, the result is +undefined. @var{m} is the mode of operand 0; operand 1's mode is +specified by the instruction pattern, and the compiler will convert the +operand to that mode before generating the instruction. + +@cindex @code{ctz@var{m}2} instruction pattern +@item @samp{ctz@var{m}2} +Store into operand 0 the number of trailing 0-bits in @var{x}, starting +at the least significant bit position. If @var{x} is 0, the result is +undefined. @var{m} is the mode of operand 0; operand 1's mode is +specified by the instruction pattern, and the compiler will convert the +operand to that mode before generating the instruction. + +@cindex @code{popcount@var{m}2} instruction pattern +@item @samp{popcount@var{m}2} +Store into operand 0 the number of 1-bits in @var{x}. @var{m} is the +mode of operand 0; operand 1's mode is specified by the instruction +pattern, and the compiler will convert the operand to that mode before +generating the instruction. + +@cindex @code{parity@var{m}2} instruction pattern +@item @samp{parity@var{m}2} +Store into operand 0 the parity of @var{x}, i.e.@: the number of 1-bits +in @var{x} modulo 2. @var{m} is the mode of operand 0; operand 1's mode +is specified by the instruction pattern, and the compiler will convert +the operand to that mode before generating the instruction. + +@cindex @code{one_cmpl@var{m}2} instruction pattern +@item @samp{one_cmpl@var{m}2} +Store the bitwise-complement of operand 1 into operand 0. + +@cindex @code{cmp@var{m}} instruction pattern +@item @samp{cmp@var{m}} +Compare operand 0 and operand 1, and set the condition codes. +The RTL pattern should look like this: + +@smallexample +(set (cc0) (compare (match_operand:@var{m} 0 @dots{}) + (match_operand:@var{m} 1 @dots{}))) +@end smallexample + +@cindex @code{tst@var{m}} instruction pattern +@item @samp{tst@var{m}} +Compare operand 0 against zero, and set the condition codes. +The RTL pattern should look like this: + +@smallexample +(set (cc0) (match_operand:@var{m} 0 @dots{})) +@end smallexample + +@samp{tst@var{m}} patterns should not be defined for machines that do +not use @code{(cc0)}. Doing so would confuse the optimizer since it +would no longer be clear which @code{set} operations were comparisons. +The @samp{cmp@var{m}} patterns should be used instead. + +@cindex @code{movmem@var{m}} instruction pattern +@item @samp{movmem@var{m}} +Block move instruction. The destination and source blocks of memory +are the first two operands, and both are @code{mem:BLK}s with an +address in mode @code{Pmode}. + +The number of bytes to move is the third operand, in mode @var{m}. +Usually, you specify @code{word_mode} for @var{m}. However, if you can +generate better code knowing the range of valid lengths is smaller than +those representable in a full word, you should provide a pattern with a +mode corresponding to the range of values you can handle efficiently +(e.g., @code{QImode} for values in the range 0--127; note we avoid numbers +that appear negative) and also a pattern with @code{word_mode}. + +The fourth operand is the known shared alignment of the source and +destination, in the form of a @code{const_int} rtx. Thus, if the +compiler knows that both source and destination are word-aligned, +it may provide the value 4 for this operand. + +Descriptions of multiple @code{movmem@var{m}} patterns can only be +beneficial if the patterns for smaller modes have fewer restrictions +on their first, second and fourth operands. Note that the mode @var{m} +in @code{movmem@var{m}} does not impose any restriction on the mode of +individually moved data units in the block. + +These patterns need not give special consideration to the possibility +that the source and destination strings might overlap. + +@cindex @code{movstr} instruction pattern +@item @samp{movstr} +String copy instruction, with @code{stpcpy} semantics. Operand 0 is +an output operand in mode @code{Pmode}. The addresses of the +destination and source strings are operands 1 and 2, and both are +@code{mem:BLK}s with addresses in mode @code{Pmode}. The execution of +the expansion of this pattern should store in operand 0 the address in +which the @code{NUL} terminator was stored in the destination string. + +@cindex @code{setmem@var{m}} instruction pattern +@item @samp{setmem@var{m}} +Block set instruction. The destination string is the first operand, +given as a @code{mem:BLK} whose address is in mode @code{Pmode}. The +number of bytes to set is the second operand, in mode @var{m}. The value to +initialize the memory with is the third operand. Targets that only support the +clearing of memory should reject any value that is not the constant 0. See +@samp{movmem@var{m}} for a discussion of the choice of mode. + +The fourth operand is the known alignment of the destination, in the form +of a @code{const_int} rtx. Thus, if the compiler knows that the +destination is word-aligned, it may provide the value 4 for this +operand. + +The use for multiple @code{setmem@var{m}} is as for @code{movmem@var{m}}. + +@cindex @code{cmpstrn@var{m}} instruction pattern +@item @samp{cmpstrn@var{m}} +String compare instruction, with five operands. Operand 0 is the output; +it has mode @var{m}. The remaining four operands are like the operands +of @samp{movmem@var{m}}. The two memory blocks specified are compared +byte by byte in lexicographic order starting at the beginning of each +string. The instruction is not allowed to prefetch more than one byte +at a time since either string may end in the first byte and reading past +that may access an invalid page or segment and cause a fault. The +effect of the instruction is to store a value in operand 0 whose sign +indicates the result of the comparison. + +@cindex @code{cmpstr@var{m}} instruction pattern +@item @samp{cmpstr@var{m}} +String compare instruction, without known maximum length. Operand 0 is the +output; it has mode @var{m}. The second and third operand are the blocks of +memory to be compared; both are @code{mem:BLK} with an address in mode +@code{Pmode}. + +The fourth operand is the known shared alignment of the source and +destination, in the form of a @code{const_int} rtx. Thus, if the +compiler knows that both source and destination are word-aligned, +it may provide the value 4 for this operand. + +The two memory blocks specified are compared byte by byte in lexicographic +order starting at the beginning of each string. The instruction is not allowed +to prefetch more than one byte at a time since either string may end in the +first byte and reading past that may access an invalid page or segment and +cause a fault. The effect of the instruction is to store a value in operand 0 +whose sign indicates the result of the comparison. + +@cindex @code{cmpmem@var{m}} instruction pattern +@item @samp{cmpmem@var{m}} +Block compare instruction, with five operands like the operands +of @samp{cmpstr@var{m}}. The two memory blocks specified are compared +byte by byte in lexicographic order starting at the beginning of each +block. Unlike @samp{cmpstr@var{m}} the instruction can prefetch +any bytes in the two memory blocks. The effect of the instruction is +to store a value in operand 0 whose sign indicates the result of the +comparison. + +@cindex @code{strlen@var{m}} instruction pattern +@item @samp{strlen@var{m}} +Compute the length of a string, with three operands. +Operand 0 is the result (of mode @var{m}), operand 1 is +a @code{mem} referring to the first character of the string, +operand 2 is the character to search for (normally zero), +and operand 3 is a constant describing the known alignment +of the beginning of the string. + +@cindex @code{float@var{mn}2} instruction pattern +@item @samp{float@var{m}@var{n}2} +Convert signed integer operand 1 (valid for fixed point mode @var{m}) to +floating point mode @var{n} and store in operand 0 (which has mode +@var{n}). + +@cindex @code{floatuns@var{mn}2} instruction pattern +@item @samp{floatuns@var{m}@var{n}2} +Convert unsigned integer operand 1 (valid for fixed point mode @var{m}) +to floating point mode @var{n} and store in operand 0 (which has mode +@var{n}). + +@cindex @code{fix@var{mn}2} instruction pattern +@item @samp{fix@var{m}@var{n}2} +Convert operand 1 (valid for floating point mode @var{m}) to fixed +point mode @var{n} as a signed number and store in operand 0 (which +has mode @var{n}). This instruction's result is defined only when +the value of operand 1 is an integer. + +If the machine description defines this pattern, it also needs to +define the @code{ftrunc} pattern. + +@cindex @code{fixuns@var{mn}2} instruction pattern +@item @samp{fixuns@var{m}@var{n}2} +Convert operand 1 (valid for floating point mode @var{m}) to fixed +point mode @var{n} as an unsigned number and store in operand 0 (which +has mode @var{n}). This instruction's result is defined only when the +value of operand 1 is an integer. + +@cindex @code{ftrunc@var{m}2} instruction pattern +@item @samp{ftrunc@var{m}2} +Convert operand 1 (valid for floating point mode @var{m}) to an +integer value, still represented in floating point mode @var{m}, and +store it in operand 0 (valid for floating point mode @var{m}). + +@cindex @code{fix_trunc@var{mn}2} instruction pattern +@item @samp{fix_trunc@var{m}@var{n}2} +Like @samp{fix@var{m}@var{n}2} but works for any floating point value +of mode @var{m} by converting the value to an integer. + +@cindex @code{fixuns_trunc@var{mn}2} instruction pattern +@item @samp{fixuns_trunc@var{m}@var{n}2} +Like @samp{fixuns@var{m}@var{n}2} but works for any floating point +value of mode @var{m} by converting the value to an integer. + +@cindex @code{trunc@var{mn}2} instruction pattern +@item @samp{trunc@var{m}@var{n}2} +Truncate operand 1 (valid for mode @var{m}) to mode @var{n} and +store in operand 0 (which has mode @var{n}). Both modes must be fixed +point or both floating point. + +@cindex @code{extend@var{mn}2} instruction pattern +@item @samp{extend@var{m}@var{n}2} +Sign-extend operand 1 (valid for mode @var{m}) to mode @var{n} and +store in operand 0 (which has mode @var{n}). Both modes must be fixed +point or both floating point. + +@cindex @code{zero_extend@var{mn}2} instruction pattern +@item @samp{zero_extend@var{m}@var{n}2} +Zero-extend operand 1 (valid for mode @var{m}) to mode @var{n} and +store in operand 0 (which has mode @var{n}). Both modes must be fixed +point. + +@cindex @code{extv} instruction pattern +@item @samp{extv} +Extract a bit-field from operand 1 (a register or memory operand), where +operand 2 specifies the width in bits and operand 3 the starting bit, +and store it in operand 0. Operand 0 must have mode @code{word_mode}. +Operand 1 may have mode @code{byte_mode} or @code{word_mode}; often +@code{word_mode} is allowed only for registers. Operands 2 and 3 must +be valid for @code{word_mode}. + +The RTL generation pass generates this instruction only with constants +for operands 2 and 3 and the constant is never zero for operand 2. + +The bit-field value is sign-extended to a full word integer +before it is stored in operand 0. + +@cindex @code{extzv} instruction pattern +@item @samp{extzv} +Like @samp{extv} except that the bit-field value is zero-extended. + +@cindex @code{insv} instruction pattern +@item @samp{insv} +Store operand 3 (which must be valid for @code{word_mode}) into a +bit-field in operand 0, where operand 1 specifies the width in bits and +operand 2 the starting bit. Operand 0 may have mode @code{byte_mode} or +@code{word_mode}; often @code{word_mode} is allowed only for registers. +Operands 1 and 2 must be valid for @code{word_mode}. + +The RTL generation pass generates this instruction only with constants +for operands 1 and 2 and the constant is never zero for operand 1. + +@cindex @code{mov@var{mode}cc} instruction pattern +@item @samp{mov@var{mode}cc} +Conditionally move operand 2 or operand 3 into operand 0 according to the +comparison in operand 1. If the comparison is true, operand 2 is moved +into operand 0, otherwise operand 3 is moved. + +The mode of the operands being compared need not be the same as the operands +being moved. Some machines, sparc64 for example, have instructions that +conditionally move an integer value based on the floating point condition +codes and vice versa. + +If the machine does not have conditional move instructions, do not +define these patterns. + +@cindex @code{add@var{mode}cc} instruction pattern +@item @samp{add@var{mode}cc} +Similar to @samp{mov@var{mode}cc} but for conditional addition. Conditionally +move operand 2 or (operands 2 + operand 3) into operand 0 according to the +comparison in operand 1. If the comparison is true, operand 2 is moved into +operand 0, otherwise (operand 2 + operand 3) is moved. + +@cindex @code{s@var{cond}} instruction pattern +@item @samp{s@var{cond}} +Store zero or nonzero in the operand according to the condition codes. +Value stored is nonzero iff the condition @var{cond} is true. +@var{cond} is the name of a comparison operation expression code, such +as @code{eq}, @code{lt} or @code{leu}. + +You specify the mode that the operand must have when you write the +@code{match_operand} expression. The compiler automatically sees +which mode you have used and supplies an operand of that mode. + +The value stored for a true condition must have 1 as its low bit, or +else must be negative. Otherwise the instruction is not suitable and +you should omit it from the machine description. You describe to the +compiler exactly which value is stored by defining the macro +@code{STORE_FLAG_VALUE} (@pxref{Misc}). If a description cannot be +found that can be used for all the @samp{s@var{cond}} patterns, you +should omit those operations from the machine description. + +These operations may fail, but should do so only in relatively +uncommon cases; if they would fail for common cases involving +integer comparisons, it is best to omit these patterns. + +If these operations are omitted, the compiler will usually generate code +that copies the constant one to the target and branches around an +assignment of zero to the target. If this code is more efficient than +the potential instructions used for the @samp{s@var{cond}} pattern +followed by those required to convert the result into a 1 or a zero in +@code{SImode}, you should omit the @samp{s@var{cond}} operations from +the machine description. + +@cindex @code{b@var{cond}} instruction pattern +@item @samp{b@var{cond}} +Conditional branch instruction. Operand 0 is a @code{label_ref} that +refers to the label to jump to. Jump if the condition codes meet +condition @var{cond}. + +Some machines do not follow the model assumed here where a comparison +instruction is followed by a conditional branch instruction. In that +case, the @samp{cmp@var{m}} (and @samp{tst@var{m}}) patterns should +simply store the operands away and generate all the required insns in a +@code{define_expand} (@pxref{Expander Definitions}) for the conditional +branch operations. All calls to expand @samp{b@var{cond}} patterns are +immediately preceded by calls to expand either a @samp{cmp@var{m}} +pattern or a @samp{tst@var{m}} pattern. + +Machines that use a pseudo register for the condition code value, or +where the mode used for the comparison depends on the condition being +tested, should also use the above mechanism. @xref{Jump Patterns}. + +The above discussion also applies to the @samp{mov@var{mode}cc} and +@samp{s@var{cond}} patterns. + +@cindex @code{cbranch@var{mode}4} instruction pattern +@item @samp{cbranch@var{mode}4} +Conditional branch instruction combined with a compare instruction. +Operand 0 is a comparison operator. Operand 1 and operand 2 are the +first and second operands of the comparison, respectively. Operand 3 +is a @code{label_ref} that refers to the label to jump to. + +@cindex @code{jump} instruction pattern +@item @samp{jump} +A jump inside a function; an unconditional branch. Operand 0 is the +@code{label_ref} of the label to jump to. This pattern name is mandatory +on all machines. + +@cindex @code{call} instruction pattern +@item @samp{call} +Subroutine call instruction returning no value. Operand 0 is the +function to call; operand 1 is the number of bytes of arguments pushed +as a @code{const_int}; operand 2 is the number of registers used as +operands. + +On most machines, operand 2 is not actually stored into the RTL +pattern. It is supplied for the sake of some RISC machines which need +to put this information into the assembler code; they can put it in +the RTL instead of operand 1. + +Operand 0 should be a @code{mem} RTX whose address is the address of the +function. Note, however, that this address can be a @code{symbol_ref} +expression even if it would not be a legitimate memory address on the +target machine. If it is also not a valid argument for a call +instruction, the pattern for this operation should be a +@code{define_expand} (@pxref{Expander Definitions}) that places the +address into a register and uses that register in the call instruction. + +@cindex @code{call_value} instruction pattern +@item @samp{call_value} +Subroutine call instruction returning a value. Operand 0 is the hard +register in which the value is returned. There are three more +operands, the same as the three operands of the @samp{call} +instruction (but with numbers increased by one). + +Subroutines that return @code{BLKmode} objects use the @samp{call} +insn. + +@cindex @code{call_pop} instruction pattern +@cindex @code{call_value_pop} instruction pattern +@item @samp{call_pop}, @samp{call_value_pop} +Similar to @samp{call} and @samp{call_value}, except used if defined and +if @code{RETURN_POPS_ARGS} is nonzero. They should emit a @code{parallel} +that contains both the function call and a @code{set} to indicate the +adjustment made to the frame pointer. + +For machines where @code{RETURN_POPS_ARGS} can be nonzero, the use of these +patterns increases the number of functions for which the frame pointer +can be eliminated, if desired. + +@cindex @code{untyped_call} instruction pattern +@item @samp{untyped_call} +Subroutine call instruction returning a value of any type. Operand 0 is +the function to call; operand 1 is a memory location where the result of +calling the function is to be stored; operand 2 is a @code{parallel} +expression where each element is a @code{set} expression that indicates +the saving of a function return value into the result block. + +This instruction pattern should be defined to support +@code{__builtin_apply} on machines where special instructions are needed +to call a subroutine with arbitrary arguments or to save the value +returned. This instruction pattern is required on machines that have +multiple registers that can hold a return value +(i.e.@: @code{FUNCTION_VALUE_REGNO_P} is true for more than one register). + +@cindex @code{return} instruction pattern +@item @samp{return} +Subroutine return instruction. This instruction pattern name should be +defined only if a single instruction can do all the work of returning +from a function. + +Like the @samp{mov@var{m}} patterns, this pattern is also used after the +RTL generation phase. In this case it is to support machines where +multiple instructions are usually needed to return from a function, but +some class of functions only requires one instruction to implement a +return. Normally, the applicable functions are those which do not need +to save any registers or allocate stack space. + +@findex reload_completed +@findex leaf_function_p +For such machines, the condition specified in this pattern should only +be true when @code{reload_completed} is nonzero and the function's +epilogue would only be a single instruction. For machines with register +windows, the routine @code{leaf_function_p} may be used to determine if +a register window push is required. + +Machines that have conditional return instructions should define patterns +such as + +@smallexample +(define_insn "" + [(set (pc) + (if_then_else (match_operator + 0 "comparison_operator" + [(cc0) (const_int 0)]) + (return) + (pc)))] + "@var{condition}" + "@dots{}") +@end smallexample + +where @var{condition} would normally be the same condition specified on the +named @samp{return} pattern. + +@cindex @code{untyped_return} instruction pattern +@item @samp{untyped_return} +Untyped subroutine return instruction. This instruction pattern should +be defined to support @code{__builtin_return} on machines where special +instructions are needed to return a value of any type. + +Operand 0 is a memory location where the result of calling a function +with @code{__builtin_apply} is stored; operand 1 is a @code{parallel} +expression where each element is a @code{set} expression that indicates +the restoring of a function return value from the result block. + +@cindex @code{nop} instruction pattern +@item @samp{nop} +No-op instruction. This instruction pattern name should always be defined +to output a no-op in assembler code. @code{(const_int 0)} will do as an +RTL pattern. + +@cindex @code{indirect_jump} instruction pattern +@item @samp{indirect_jump} +An instruction to jump to an address which is operand zero. +This pattern name is mandatory on all machines. + +@cindex @code{casesi} instruction pattern +@item @samp{casesi} +Instruction to jump through a dispatch table, including bounds checking. +This instruction takes five operands: + +@enumerate +@item +The index to dispatch on, which has mode @code{SImode}. + +@item +The lower bound for indices in the table, an integer constant. + +@item +The total range of indices in the table---the largest index +minus the smallest one (both inclusive). + +@item +A label that precedes the table itself. + +@item +A label to jump to if the index has a value outside the bounds. +@end enumerate + +The table is a @code{addr_vec} or @code{addr_diff_vec} inside of a +@code{jump_insn}. The number of elements in the table is one plus the +difference between the upper bound and the lower bound. + +@cindex @code{tablejump} instruction pattern +@item @samp{tablejump} +Instruction to jump to a variable address. This is a low-level +capability which can be used to implement a dispatch table when there +is no @samp{casesi} pattern. + +This pattern requires two operands: the address or offset, and a label +which should immediately precede the jump table. If the macro +@code{CASE_VECTOR_PC_RELATIVE} evaluates to a nonzero value then the first +operand is an offset which counts from the address of the table; otherwise, +it is an absolute address to jump to. In either case, the first operand has +mode @code{Pmode}. + +The @samp{tablejump} insn is always the last insn before the jump +table it uses. Its assembler code normally has no need to use the +second operand, but you should incorporate it in the RTL pattern so +that the jump optimizer will not delete the table as unreachable code. + + +@cindex @code{decrement_and_branch_until_zero} instruction pattern +@item @samp{decrement_and_branch_until_zero} +Conditional branch instruction that decrements a register and +jumps if the register is nonzero. Operand 0 is the register to +decrement and test; operand 1 is the label to jump to if the +register is nonzero. @xref{Looping Patterns}. + +This optional instruction pattern is only used by the combiner, +typically for loops reversed by the loop optimizer when strength +reduction is enabled. + +@cindex @code{doloop_end} instruction pattern +@item @samp{doloop_end} +Conditional branch instruction that decrements a register and jumps if +the register is nonzero. This instruction takes five operands: Operand +0 is the register to decrement and test; operand 1 is the number of loop +iterations as a @code{const_int} or @code{const0_rtx} if this cannot be +determined until run-time; operand 2 is the actual or estimated maximum +number of iterations as a @code{const_int}; operand 3 is the number of +enclosed loops as a @code{const_int} (an innermost loop has a value of +1); operand 4 is the label to jump to if the register is nonzero. +@xref{Looping Patterns}. + +This optional instruction pattern should be defined for machines with +low-overhead looping instructions as the loop optimizer will try to +modify suitable loops to utilize it. If nested low-overhead looping is +not supported, use a @code{define_expand} (@pxref{Expander Definitions}) +and make the pattern fail if operand 3 is not @code{const1_rtx}. +Similarly, if the actual or estimated maximum number of iterations is +too large for this instruction, make it fail. + +@cindex @code{doloop_begin} instruction pattern +@item @samp{doloop_begin} +Companion instruction to @code{doloop_end} required for machines that +need to perform some initialization, such as loading special registers +used by a low-overhead looping instruction. If initialization insns do +not always need to be emitted, use a @code{define_expand} +(@pxref{Expander Definitions}) and make it fail. + + +@cindex @code{canonicalize_funcptr_for_compare} instruction pattern +@item @samp{canonicalize_funcptr_for_compare} +Canonicalize the function pointer in operand 1 and store the result +into operand 0. + +Operand 0 is always a @code{reg} and has mode @code{Pmode}; operand 1 +may be a @code{reg}, @code{mem}, @code{symbol_ref}, @code{const_int}, etc +and also has mode @code{Pmode}. + +Canonicalization of a function pointer usually involves computing +the address of the function which would be called if the function +pointer were used in an indirect call. + +Only define this pattern if function pointers on the target machine +can have different values but still call the same function when +used in an indirect call. + +@cindex @code{save_stack_block} instruction pattern +@cindex @code{save_stack_function} instruction pattern +@cindex @code{save_stack_nonlocal} instruction pattern +@cindex @code{restore_stack_block} instruction pattern +@cindex @code{restore_stack_function} instruction pattern +@cindex @code{restore_stack_nonlocal} instruction pattern +@item @samp{save_stack_block} +@itemx @samp{save_stack_function} +@itemx @samp{save_stack_nonlocal} +@itemx @samp{restore_stack_block} +@itemx @samp{restore_stack_function} +@itemx @samp{restore_stack_nonlocal} +Most machines save and restore the stack pointer by copying it to or +from an object of mode @code{Pmode}. Do not define these patterns on +such machines. + +Some machines require special handling for stack pointer saves and +restores. On those machines, define the patterns corresponding to the +non-standard cases by using a @code{define_expand} (@pxref{Expander +Definitions}) that produces the required insns. The three types of +saves and restores are: + +@enumerate +@item +@samp{save_stack_block} saves the stack pointer at the start of a block +that allocates a variable-sized object, and @samp{restore_stack_block} +restores the stack pointer when the block is exited. + +@item +@samp{save_stack_function} and @samp{restore_stack_function} do a +similar job for the outermost block of a function and are used when the +function allocates variable-sized objects or calls @code{alloca}. Only +the epilogue uses the restored stack pointer, allowing a simpler save or +restore sequence on some machines. + +@item +@samp{save_stack_nonlocal} is used in functions that contain labels +branched to by nested functions. It saves the stack pointer in such a +way that the inner function can use @samp{restore_stack_nonlocal} to +restore the stack pointer. The compiler generates code to restore the +frame and argument pointer registers, but some machines require saving +and restoring additional data such as register window information or +stack backchains. Place insns in these patterns to save and restore any +such required data. +@end enumerate + +When saving the stack pointer, operand 0 is the save area and operand 1 +is the stack pointer. The mode used to allocate the save area defaults +to @code{Pmode} but you can override that choice by defining the +@code{STACK_SAVEAREA_MODE} macro (@pxref{Storage Layout}). You must +specify an integral mode, or @code{VOIDmode} if no save area is needed +for a particular type of save (either because no save is needed or +because a machine-specific save area can be used). Operand 0 is the +stack pointer and operand 1 is the save area for restore operations. If +@samp{save_stack_block} is defined, operand 0 must not be +@code{VOIDmode} since these saves can be arbitrarily nested. + +A save area is a @code{mem} that is at a constant offset from +@code{virtual_stack_vars_rtx} when the stack pointer is saved for use by +nonlocal gotos and a @code{reg} in the other two cases. + +@cindex @code{allocate_stack} instruction pattern +@item @samp{allocate_stack} +Subtract (or add if @code{STACK_GROWS_DOWNWARD} is undefined) operand 1 from +the stack pointer to create space for dynamically allocated data. + +Store the resultant pointer to this space into operand 0. If you +are allocating space from the main stack, do this by emitting a +move insn to copy @code{virtual_stack_dynamic_rtx} to operand 0. +If you are allocating the space elsewhere, generate code to copy the +location of the space to operand 0. In the latter case, you must +ensure this space gets freed when the corresponding space on the main +stack is free. + +Do not define this pattern if all that must be done is the subtraction. +Some machines require other operations such as stack probes or +maintaining the back chain. Define this pattern to emit those +operations in addition to updating the stack pointer. + +@cindex @code{check_stack} instruction pattern +@item @samp{check_stack} +If stack checking cannot be done on your system by probing the stack with +a load or store instruction (@pxref{Stack Checking}), define this pattern +to perform the needed check and signaling an error if the stack +has overflowed. The single operand is the location in the stack furthest +from the current stack pointer that you need to validate. Normally, +on machines where this pattern is needed, you would obtain the stack +limit from a global or thread-specific variable or register. + +@cindex @code{nonlocal_goto} instruction pattern +@item @samp{nonlocal_goto} +Emit code to generate a non-local goto, e.g., a jump from one function +to a label in an outer function. This pattern has four arguments, +each representing a value to be used in the jump. The first +argument is to be loaded into the frame pointer, the second is +the address to branch to (code to dispatch to the actual label), +the third is the address of a location where the stack is saved, +and the last is the address of the label, to be placed in the +location for the incoming static chain. + +On most machines you need not define this pattern, since GCC will +already generate the correct code, which is to load the frame pointer +and static chain, restore the stack (using the +@samp{restore_stack_nonlocal} pattern, if defined), and jump indirectly +to the dispatcher. You need only define this pattern if this code will +not work on your machine. + +@cindex @code{nonlocal_goto_receiver} instruction pattern +@item @samp{nonlocal_goto_receiver} +This pattern, if defined, contains code needed at the target of a +nonlocal goto after the code already generated by GCC@. You will not +normally need to define this pattern. A typical reason why you might +need this pattern is if some value, such as a pointer to a global table, +must be restored when the frame pointer is restored. Note that a nonlocal +goto only occurs within a unit-of-translation, so a global table pointer +that is shared by all functions of a given module need not be restored. +There are no arguments. + +@cindex @code{exception_receiver} instruction pattern +@item @samp{exception_receiver} +This pattern, if defined, contains code needed at the site of an +exception handler that isn't needed at the site of a nonlocal goto. You +will not normally need to define this pattern. A typical reason why you +might need this pattern is if some value, such as a pointer to a global +table, must be restored after control flow is branched to the handler of +an exception. There are no arguments. + +@cindex @code{builtin_setjmp_setup} instruction pattern +@item @samp{builtin_setjmp_setup} +This pattern, if defined, contains additional code needed to initialize +the @code{jmp_buf}. You will not normally need to define this pattern. +A typical reason why you might need this pattern is if some value, such +as a pointer to a global table, must be restored. Though it is +preferred that the pointer value be recalculated if possible (given the +address of a label for instance). The single argument is a pointer to +the @code{jmp_buf}. Note that the buffer is five words long and that +the first three are normally used by the generic mechanism. + +@cindex @code{builtin_setjmp_receiver} instruction pattern +@item @samp{builtin_setjmp_receiver} +This pattern, if defined, contains code needed at the site of an +built-in setjmp that isn't needed at the site of a nonlocal goto. You +will not normally need to define this pattern. A typical reason why you +might need this pattern is if some value, such as a pointer to a global +table, must be restored. It takes one argument, which is the label +to which builtin_longjmp transfered control; this pattern may be emitted +at a small offset from that label. + +@cindex @code{builtin_longjmp} instruction pattern +@item @samp{builtin_longjmp} +This pattern, if defined, performs the entire action of the longjmp. +You will not normally need to define this pattern unless you also define +@code{builtin_setjmp_setup}. The single argument is a pointer to the +@code{jmp_buf}. + +@cindex @code{eh_return} instruction pattern +@item @samp{eh_return} +This pattern, if defined, affects the way @code{__builtin_eh_return}, +and thence the call frame exception handling library routines, are +built. It is intended to handle non-trivial actions needed along +the abnormal return path. + +The address of the exception handler to which the function should return +is passed as operand to this pattern. It will normally need to copied by +the pattern to some special register or memory location. +If the pattern needs to determine the location of the target call +frame in order to do so, it may use @code{EH_RETURN_STACKADJ_RTX}, +if defined; it will have already been assigned. + +If this pattern is not defined, the default action will be to simply +copy the return address to @code{EH_RETURN_HANDLER_RTX}. Either +that macro or this pattern needs to be defined if call frame exception +handling is to be used. + +@cindex @code{prologue} instruction pattern +@anchor{prologue instruction pattern} +@item @samp{prologue} +This pattern, if defined, emits RTL for entry to a function. The function +entry is responsible for setting up the stack frame, initializing the frame +pointer register, saving callee saved registers, etc. + +Using a prologue pattern is generally preferred over defining +@code{TARGET_ASM_FUNCTION_PROLOGUE} to emit assembly code for the prologue. + +The @code{prologue} pattern is particularly useful for targets which perform +instruction scheduling. + +@cindex @code{epilogue} instruction pattern +@anchor{epilogue instruction pattern} +@item @samp{epilogue} +This pattern emits RTL for exit from a function. The function +exit is responsible for deallocating the stack frame, restoring callee saved +registers and emitting the return instruction. + +Using an epilogue pattern is generally preferred over defining +@code{TARGET_ASM_FUNCTION_EPILOGUE} to emit assembly code for the epilogue. + +The @code{epilogue} pattern is particularly useful for targets which perform +instruction scheduling or which have delay slots for their return instruction. + +@cindex @code{sibcall_epilogue} instruction pattern +@item @samp{sibcall_epilogue} +This pattern, if defined, emits RTL for exit from a function without the final +branch back to the calling function. This pattern will be emitted before any +sibling call (aka tail call) sites. + +The @code{sibcall_epilogue} pattern must not clobber any arguments used for +parameter passing or any stack slots for arguments passed to the current +function. + +@cindex @code{trap} instruction pattern +@item @samp{trap} +This pattern, if defined, signals an error, typically by causing some +kind of signal to be raised. Among other places, it is used by the Java +front end to signal `invalid array index' exceptions. + +@cindex @code{conditional_trap} instruction pattern +@item @samp{conditional_trap} +Conditional trap instruction. Operand 0 is a piece of RTL which +performs a comparison. Operand 1 is the trap code, an integer. + +A typical @code{conditional_trap} pattern looks like + +@smallexample +(define_insn "conditional_trap" + [(trap_if (match_operator 0 "trap_operator" + [(cc0) (const_int 0)]) + (match_operand 1 "const_int_operand" "i"))] + "" + "@dots{}") +@end smallexample + +@cindex @code{prefetch} instruction pattern +@item @samp{prefetch} + +This pattern, if defined, emits code for a non-faulting data prefetch +instruction. Operand 0 is the address of the memory to prefetch. Operand 1 +is a constant 1 if the prefetch is preparing for a write to the memory +address, or a constant 0 otherwise. Operand 2 is the expected degree of +temporal locality of the data and is a value between 0 and 3, inclusive; 0 +means that the data has no temporal locality, so it need not be left in the +cache after the access; 3 means that the data has a high degree of temporal +locality and should be left in all levels of cache possible; 1 and 2 mean, +respectively, a low or moderate degree of temporal locality. + +Targets that do not support write prefetches or locality hints can ignore +the values of operands 1 and 2. + +@cindex @code{memory_barrier} instruction pattern +@item @samp{memory_barrier} + +If the target memory model is not fully synchronous, then this pattern +should be defined to an instruction that orders both loads and stores +before the instruction with respect to loads and stores after the instruction. +This pattern has no operands. + +@cindex @code{sync_compare_and_swap@var{mode}} instruction pattern +@item @samp{sync_compare_and_swap@var{mode}} + +This pattern, if defined, emits code for an atomic compare-and-swap +operation. Operand 1 is the memory on which the atomic operation is +performed. Operand 2 is the ``old'' value to be compared against the +current contents of the memory location. Operand 3 is the ``new'' value +to store in the memory if the compare succeeds. Operand 0 is the result +of the operation; it should contain the contents of the memory +before the operation. If the compare succeeds, this should obviously be +a copy of operand 2. + +This pattern must show that both operand 0 and operand 1 are modified. + +This pattern must issue any memory barrier instructions such that all +memory operations before the atomic operation occur before the atomic +operation and all memory operations after the atomic operation occur +after the atomic operation. + +@cindex @code{sync_compare_and_swap_cc@var{mode}} instruction pattern +@item @samp{sync_compare_and_swap_cc@var{mode}} + +This pattern is just like @code{sync_compare_and_swap@var{mode}}, except +it should act as if compare part of the compare-and-swap were issued via +@code{cmp@var{m}}. This comparison will only be used with @code{EQ} and +@code{NE} branches and @code{setcc} operations. + +Some targets do expose the success or failure of the compare-and-swap +operation via the status flags. Ideally we wouldn't need a separate +named pattern in order to take advantage of this, but the combine pass +does not handle patterns with multiple sets, which is required by +definition for @code{sync_compare_and_swap@var{mode}}. + +@cindex @code{sync_add@var{mode}} instruction pattern +@cindex @code{sync_sub@var{mode}} instruction pattern +@cindex @code{sync_ior@var{mode}} instruction pattern +@cindex @code{sync_and@var{mode}} instruction pattern +@cindex @code{sync_xor@var{mode}} instruction pattern +@cindex @code{sync_nand@var{mode}} instruction pattern +@item @samp{sync_add@var{mode}}, @samp{sync_sub@var{mode}} +@itemx @samp{sync_ior@var{mode}}, @samp{sync_and@var{mode}} +@itemx @samp{sync_xor@var{mode}}, @samp{sync_nand@var{mode}} + +These patterns emit code for an atomic operation on memory. +Operand 0 is the memory on which the atomic operation is performed. +Operand 1 is the second operand to the binary operator. + +The ``nand'' operation is @code{~op0 & op1}. + +This pattern must issue any memory barrier instructions such that all +memory operations before the atomic operation occur before the atomic +operation and all memory operations after the atomic operation occur +after the atomic operation. + +If these patterns are not defined, the operation will be constructed +from a compare-and-swap operation, if defined. + +@cindex @code{sync_old_add@var{mode}} instruction pattern +@cindex @code{sync_old_sub@var{mode}} instruction pattern +@cindex @code{sync_old_ior@var{mode}} instruction pattern +@cindex @code{sync_old_and@var{mode}} instruction pattern +@cindex @code{sync_old_xor@var{mode}} instruction pattern +@cindex @code{sync_old_nand@var{mode}} instruction pattern +@item @samp{sync_old_add@var{mode}}, @samp{sync_old_sub@var{mode}} +@itemx @samp{sync_old_ior@var{mode}}, @samp{sync_old_and@var{mode}} +@itemx @samp{sync_old_xor@var{mode}}, @samp{sync_old_nand@var{mode}} + +These patterns are emit code for an atomic operation on memory, +and return the value that the memory contained before the operation. +Operand 0 is the result value, operand 1 is the memory on which the +atomic operation is performed, and operand 2 is the second operand +to the binary operator. + +This pattern must issue any memory barrier instructions such that all +memory operations before the atomic operation occur before the atomic +operation and all memory operations after the atomic operation occur +after the atomic operation. + +If these patterns are not defined, the operation will be constructed +from a compare-and-swap operation, if defined. + +@cindex @code{sync_new_add@var{mode}} instruction pattern +@cindex @code{sync_new_sub@var{mode}} instruction pattern +@cindex @code{sync_new_ior@var{mode}} instruction pattern +@cindex @code{sync_new_and@var{mode}} instruction pattern +@cindex @code{sync_new_xor@var{mode}} instruction pattern +@cindex @code{sync_new_nand@var{mode}} instruction pattern +@item @samp{sync_new_add@var{mode}}, @samp{sync_new_sub@var{mode}} +@itemx @samp{sync_new_ior@var{mode}}, @samp{sync_new_and@var{mode}} +@itemx @samp{sync_new_xor@var{mode}}, @samp{sync_new_nand@var{mode}} + +These patterns are like their @code{sync_old_@var{op}} counterparts, +except that they return the value that exists in the memory location +after the operation, rather than before the operation. + +@cindex @code{sync_lock_test_and_set@var{mode}} instruction pattern +@item @samp{sync_lock_test_and_set@var{mode}} + +This pattern takes two forms, based on the capabilities of the target. +In either case, operand 0 is the result of the operand, operand 1 is +the memory on which the atomic operation is performed, and operand 2 +is the value to set in the lock. + +In the ideal case, this operation is an atomic exchange operation, in +which the previous value in memory operand is copied into the result +operand, and the value operand is stored in the memory operand. + +For less capable targets, any value operand that is not the constant 1 +should be rejected with @code{FAIL}. In this case the target may use +an atomic test-and-set bit operation. The result operand should contain +1 if the bit was previously set and 0 if the bit was previously clear. +The true contents of the memory operand are implementation defined. + +This pattern must issue any memory barrier instructions such that the +pattern as a whole acts as an acquire barrier, that is all memory +operations after the pattern do not occur until the lock is acquired. + +If this pattern is not defined, the operation will be constructed from +a compare-and-swap operation, if defined. + +@cindex @code{sync_lock_release@var{mode}} instruction pattern +@item @samp{sync_lock_release@var{mode}} + +This pattern, if defined, releases a lock set by +@code{sync_lock_test_and_set@var{mode}}. Operand 0 is the memory +that contains the lock; operand 1 is the value to store in the lock. + +If the target doesn't implement full semantics for +@code{sync_lock_test_and_set@var{mode}}, any value operand which is not +the constant 0 should be rejected with @code{FAIL}, and the true contents +of the memory operand are implementation defined. + +This pattern must issue any memory barrier instructions such that the +pattern as a whole acts as a release barrier, that is the lock is +released only after all previous memory operations have completed. + +If this pattern is not defined, then a @code{memory_barrier} pattern +will be emitted, followed by a store of the value to the memory operand. + +@cindex @code{stack_protect_set} instruction pattern +@item @samp{stack_protect_set} + +This pattern, if defined, moves a @code{Pmode} value from the memory +in operand 1 to the memory in operand 0 without leaving the value in +a register afterward. This is to avoid leaking the value some place +that an attacker might use to rewrite the stack guard slot after +having clobbered it. + +If this pattern is not defined, then a plain move pattern is generated. + +@cindex @code{stack_protect_test} instruction pattern +@item @samp{stack_protect_test} + +This pattern, if defined, compares a @code{Pmode} value from the +memory in operand 1 with the memory in operand 0 without leaving the +value in a register afterward and branches to operand 2 if the values +weren't equal. + +If this pattern is not defined, then a plain compare pattern and +conditional branch pattern is used. + +@end table + +@end ifset +@c Each of the following nodes are wrapped in separate +@c "@ifset INTERNALS" to work around memory limits for the default +@c configuration in older tetex distributions. Known to not work: +@c tetex-1.0.7, known to work: tetex-2.0.2. +@ifset INTERNALS +@node Pattern Ordering +@section When the Order of Patterns Matters +@cindex Pattern Ordering +@cindex Ordering of Patterns + +Sometimes an insn can match more than one instruction pattern. Then the +pattern that appears first in the machine description is the one used. +Therefore, more specific patterns (patterns that will match fewer things) +and faster instructions (those that will produce better code when they +do match) should usually go first in the description. + +In some cases the effect of ordering the patterns can be used to hide +a pattern when it is not valid. For example, the 68000 has an +instruction for converting a fullword to floating point and another +for converting a byte to floating point. An instruction converting +an integer to floating point could match either one. We put the +pattern to convert the fullword first to make sure that one will +be used rather than the other. (Otherwise a large integer might +be generated as a single-byte immediate quantity, which would not work.) +Instead of using this pattern ordering it would be possible to make the +pattern for convert-a-byte smart enough to deal properly with any +constant value. + +@end ifset +@ifset INTERNALS +@node Dependent Patterns +@section Interdependence of Patterns +@cindex Dependent Patterns +@cindex Interdependence of Patterns + +Every machine description must have a named pattern for each of the +conditional branch names @samp{b@var{cond}}. The recognition template +must always have the form + +@smallexample +(set (pc) + (if_then_else (@var{cond} (cc0) (const_int 0)) + (label_ref (match_operand 0 "" "")) + (pc))) +@end smallexample + +@noindent +In addition, every machine description must have an anonymous pattern +for each of the possible reverse-conditional branches. Their templates +look like + +@smallexample +(set (pc) + (if_then_else (@var{cond} (cc0) (const_int 0)) + (pc) + (label_ref (match_operand 0 "" "")))) +@end smallexample + +@noindent +They are necessary because jump optimization can turn direct-conditional +branches into reverse-conditional branches. + +It is often convenient to use the @code{match_operator} construct to +reduce the number of patterns that must be specified for branches. For +example, + +@smallexample +(define_insn "" + [(set (pc) + (if_then_else (match_operator 0 "comparison_operator" + [(cc0) (const_int 0)]) + (pc) + (label_ref (match_operand 1 "" ""))))] + "@var{condition}" + "@dots{}") +@end smallexample + +In some cases machines support instructions identical except for the +machine mode of one or more operands. For example, there may be +``sign-extend halfword'' and ``sign-extend byte'' instructions whose +patterns are + +@smallexample +(set (match_operand:SI 0 @dots{}) + (extend:SI (match_operand:HI 1 @dots{}))) + +(set (match_operand:SI 0 @dots{}) + (extend:SI (match_operand:QI 1 @dots{}))) +@end smallexample + +@noindent +Constant integers do not specify a machine mode, so an instruction to +extend a constant value could match either pattern. The pattern it +actually will match is the one that appears first in the file. For correct +results, this must be the one for the widest possible mode (@code{HImode}, +here). If the pattern matches the @code{QImode} instruction, the results +will be incorrect if the constant value does not actually fit that mode. + +Such instructions to extend constants are rarely generated because they are +optimized away, but they do occasionally happen in nonoptimized +compilations. + +If a constraint in a pattern allows a constant, the reload pass may +replace a register with a constant permitted by the constraint in some +cases. Similarly for memory references. Because of this substitution, +you should not provide separate patterns for increment and decrement +instructions. Instead, they should be generated from the same pattern +that supports register-register add insns by examining the operands and +generating the appropriate machine instruction. + +@end ifset +@ifset INTERNALS +@node Jump Patterns +@section Defining Jump Instruction Patterns +@cindex jump instruction patterns +@cindex defining jump instruction patterns + +For most machines, GCC assumes that the machine has a condition code. +A comparison insn sets the condition code, recording the results of both +signed and unsigned comparison of the given operands. A separate branch +insn tests the condition code and branches or not according its value. +The branch insns come in distinct signed and unsigned flavors. Many +common machines, such as the VAX, the 68000 and the 32000, work this +way. + +Some machines have distinct signed and unsigned compare instructions, and +only one set of conditional branch instructions. The easiest way to handle +these machines is to treat them just like the others until the final stage +where assembly code is written. At this time, when outputting code for the +compare instruction, peek ahead at the following branch using +@code{next_cc0_user (insn)}. (The variable @code{insn} refers to the insn +being output, in the output-writing code in an instruction pattern.) If +the RTL says that is an unsigned branch, output an unsigned compare; +otherwise output a signed compare. When the branch itself is output, you +can treat signed and unsigned branches identically. + +The reason you can do this is that GCC always generates a pair of +consecutive RTL insns, possibly separated by @code{note} insns, one to +set the condition code and one to test it, and keeps the pair inviolate +until the end. + +To go with this technique, you must define the machine-description macro +@code{NOTICE_UPDATE_CC} to do @code{CC_STATUS_INIT}; in other words, no +compare instruction is superfluous. + +Some machines have compare-and-branch instructions and no condition code. +A similar technique works for them. When it is time to ``output'' a +compare instruction, record its operands in two static variables. When +outputting the branch-on-condition-code instruction that follows, actually +output a compare-and-branch instruction that uses the remembered operands. + +It also works to define patterns for compare-and-branch instructions. +In optimizing compilation, the pair of compare and branch instructions +will be combined according to these patterns. But this does not happen +if optimization is not requested. So you must use one of the solutions +above in addition to any special patterns you define. + +In many RISC machines, most instructions do not affect the condition +code and there may not even be a separate condition code register. On +these machines, the restriction that the definition and use of the +condition code be adjacent insns is not necessary and can prevent +important optimizations. For example, on the IBM RS/6000, there is a +delay for taken branches unless the condition code register is set three +instructions earlier than the conditional branch. The instruction +scheduler cannot perform this optimization if it is not permitted to +separate the definition and use of the condition code register. + +On these machines, do not use @code{(cc0)}, but instead use a register +to represent the condition code. If there is a specific condition code +register in the machine, use a hard register. If the condition code or +comparison result can be placed in any general register, or if there are +multiple condition registers, use a pseudo register. + +@findex prev_cc0_setter +@findex next_cc0_user +On some machines, the type of branch instruction generated may depend on +the way the condition code was produced; for example, on the 68k and +SPARC, setting the condition code directly from an add or subtract +instruction does not clear the overflow bit the way that a test +instruction does, so a different branch instruction must be used for +some conditional branches. For machines that use @code{(cc0)}, the set +and use of the condition code must be adjacent (separated only by +@code{note} insns) allowing flags in @code{cc_status} to be used. +(@xref{Condition Code}.) Also, the comparison and branch insns can be +located from each other by using the functions @code{prev_cc0_setter} +and @code{next_cc0_user}. + +However, this is not true on machines that do not use @code{(cc0)}. On +those machines, no assumptions can be made about the adjacency of the +compare and branch insns and the above methods cannot be used. Instead, +we use the machine mode of the condition code register to record +different formats of the condition code register. + +Registers used to store the condition code value should have a mode that +is in class @code{MODE_CC}. Normally, it will be @code{CCmode}. If +additional modes are required (as for the add example mentioned above in +the SPARC), define them in @file{@var{machine}-modes.def} +(@pxref{Condition Code}). Also define @code{SELECT_CC_MODE} to choose +a mode given an operand of a compare. + +If it is known during RTL generation that a different mode will be +required (for example, if the machine has separate compare instructions +for signed and unsigned quantities, like most IBM processors), they can +be specified at that time. + +If the cases that require different modes would be made by instruction +combination, the macro @code{SELECT_CC_MODE} determines which machine +mode should be used for the comparison result. The patterns should be +written using that mode. To support the case of the add on the SPARC +discussed above, we have the pattern + +@smallexample +(define_insn "" + [(set (reg:CC_NOOV 0) + (compare:CC_NOOV + (plus:SI (match_operand:SI 0 "register_operand" "%r") + (match_operand:SI 1 "arith_operand" "rI")) + (const_int 0)))] + "" + "@dots{}") +@end smallexample + +The @code{SELECT_CC_MODE} macro on the SPARC returns @code{CC_NOOVmode} +for comparisons whose argument is a @code{plus}. + +@end ifset +@ifset INTERNALS +@node Looping Patterns +@section Defining Looping Instruction Patterns +@cindex looping instruction patterns +@cindex defining looping instruction patterns + +Some machines have special jump instructions that can be utilized to +make loops more efficient. A common example is the 68000 @samp{dbra} +instruction which performs a decrement of a register and a branch if the +result was greater than zero. Other machines, in particular digital +signal processors (DSPs), have special block repeat instructions to +provide low-overhead loop support. For example, the TI TMS320C3x/C4x +DSPs have a block repeat instruction that loads special registers to +mark the top and end of a loop and to count the number of loop +iterations. This avoids the need for fetching and executing a +@samp{dbra}-like instruction and avoids pipeline stalls associated with +the jump. + +GCC has three special named patterns to support low overhead looping. +They are @samp{decrement_and_branch_until_zero}, @samp{doloop_begin}, +and @samp{doloop_end}. The first pattern, +@samp{decrement_and_branch_until_zero}, is not emitted during RTL +generation but may be emitted during the instruction combination phase. +This requires the assistance of the loop optimizer, using information +collected during strength reduction, to reverse a loop to count down to +zero. Some targets also require the loop optimizer to add a +@code{REG_NONNEG} note to indicate that the iteration count is always +positive. This is needed if the target performs a signed loop +termination test. For example, the 68000 uses a pattern similar to the +following for its @code{dbra} instruction: + +@smallexample +@group +(define_insn "decrement_and_branch_until_zero" + [(set (pc) + (if_then_else + (ge (plus:SI (match_operand:SI 0 "general_operand" "+d*am") + (const_int -1)) + (const_int 0)) + (label_ref (match_operand 1 "" "")) + (pc))) + (set (match_dup 0) + (plus:SI (match_dup 0) + (const_int -1)))] + "find_reg_note (insn, REG_NONNEG, 0)" + "@dots{}") +@end group +@end smallexample + +Note that since the insn is both a jump insn and has an output, it must +deal with its own reloads, hence the `m' constraints. Also note that +since this insn is generated by the instruction combination phase +combining two sequential insns together into an implicit parallel insn, +the iteration counter needs to be biased by the same amount as the +decrement operation, in this case @minus{}1. Note that the following similar +pattern will not be matched by the combiner. + +@smallexample +@group +(define_insn "decrement_and_branch_until_zero" + [(set (pc) + (if_then_else + (ge (match_operand:SI 0 "general_operand" "+d*am") + (const_int 1)) + (label_ref (match_operand 1 "" "")) + (pc))) + (set (match_dup 0) + (plus:SI (match_dup 0) + (const_int -1)))] + "find_reg_note (insn, REG_NONNEG, 0)" + "@dots{}") +@end group +@end smallexample + +The other two special looping patterns, @samp{doloop_begin} and +@samp{doloop_end}, are emitted by the loop optimizer for certain +well-behaved loops with a finite number of loop iterations using +information collected during strength reduction. + +The @samp{doloop_end} pattern describes the actual looping instruction +(or the implicit looping operation) and the @samp{doloop_begin} pattern +is an optional companion pattern that can be used for initialization +needed for some low-overhead looping instructions. + +Note that some machines require the actual looping instruction to be +emitted at the top of the loop (e.g., the TMS320C3x/C4x DSPs). Emitting +the true RTL for a looping instruction at the top of the loop can cause +problems with flow analysis. So instead, a dummy @code{doloop} insn is +emitted at the end of the loop. The machine dependent reorg pass checks +for the presence of this @code{doloop} insn and then searches back to +the top of the loop, where it inserts the true looping insn (provided +there are no instructions in the loop which would cause problems). Any +additional labels can be emitted at this point. In addition, if the +desired special iteration counter register was not allocated, this +machine dependent reorg pass could emit a traditional compare and jump +instruction pair. + +The essential difference between the +@samp{decrement_and_branch_until_zero} and the @samp{doloop_end} +patterns is that the loop optimizer allocates an additional pseudo +register for the latter as an iteration counter. This pseudo register +cannot be used within the loop (i.e., general induction variables cannot +be derived from it), however, in many cases the loop induction variable +may become redundant and removed by the flow pass. + + +@end ifset +@ifset INTERNALS +@node Insn Canonicalizations +@section Canonicalization of Instructions +@cindex canonicalization of instructions +@cindex insn canonicalization + +There are often cases where multiple RTL expressions could represent an +operation performed by a single machine instruction. This situation is +most commonly encountered with logical, branch, and multiply-accumulate +instructions. In such cases, the compiler attempts to convert these +multiple RTL expressions into a single canonical form to reduce the +number of insn patterns required. + +In addition to algebraic simplifications, following canonicalizations +are performed: + +@itemize @bullet +@item +For commutative and comparison operators, a constant is always made the +second operand. If a machine only supports a constant as the second +operand, only patterns that match a constant in the second operand need +be supplied. + +@item +For associative operators, a sequence of operators will always chain +to the left; for instance, only the left operand of an integer @code{plus} +can itself be a @code{plus}. @code{and}, @code{ior}, @code{xor}, +@code{plus}, @code{mult}, @code{smin}, @code{smax}, @code{umin}, and +@code{umax} are associative when applied to integers, and sometimes to +floating-point. + +@item +@cindex @code{neg}, canonicalization of +@cindex @code{not}, canonicalization of +@cindex @code{mult}, canonicalization of +@cindex @code{plus}, canonicalization of +@cindex @code{minus}, canonicalization of +For these operators, if only one operand is a @code{neg}, @code{not}, +@code{mult}, @code{plus}, or @code{minus} expression, it will be the +first operand. + +@item +In combinations of @code{neg}, @code{mult}, @code{plus}, and +@code{minus}, the @code{neg} operations (if any) will be moved inside +the operations as far as possible. For instance, +@code{(neg (mult A B))} is canonicalized as @code{(mult (neg A) B)}, but +@code{(plus (mult (neg A) B) C)} is canonicalized as +@code{(minus A (mult B C))}. + +@cindex @code{compare}, canonicalization of +@item +For the @code{compare} operator, a constant is always the second operand +on machines where @code{cc0} is used (@pxref{Jump Patterns}). On other +machines, there are rare cases where the compiler might want to construct +a @code{compare} with a constant as the first operand. However, these +cases are not common enough for it to be worthwhile to provide a pattern +matching a constant as the first operand unless the machine actually has +such an instruction. + +An operand of @code{neg}, @code{not}, @code{mult}, @code{plus}, or +@code{minus} is made the first operand under the same conditions as +above. + +@item +@code{(minus @var{x} (const_int @var{n}))} is converted to +@code{(plus @var{x} (const_int @var{-n}))}. + +@item +Within address computations (i.e., inside @code{mem}), a left shift is +converted into the appropriate multiplication by a power of two. + +@cindex @code{ior}, canonicalization of +@cindex @code{and}, canonicalization of +@cindex De Morgan's law +@item +De Morgan's Law is used to move bitwise negation inside a bitwise +logical-and or logical-or operation. If this results in only one +operand being a @code{not} expression, it will be the first one. + +A machine that has an instruction that performs a bitwise logical-and of one +operand with the bitwise negation of the other should specify the pattern +for that instruction as + +@smallexample +(define_insn "" + [(set (match_operand:@var{m} 0 @dots{}) + (and:@var{m} (not:@var{m} (match_operand:@var{m} 1 @dots{})) + (match_operand:@var{m} 2 @dots{})))] + "@dots{}" + "@dots{}") +@end smallexample + +@noindent +Similarly, a pattern for a ``NAND'' instruction should be written + +@smallexample +(define_insn "" + [(set (match_operand:@var{m} 0 @dots{}) + (ior:@var{m} (not:@var{m} (match_operand:@var{m} 1 @dots{})) + (not:@var{m} (match_operand:@var{m} 2 @dots{}))))] + "@dots{}" + "@dots{}") +@end smallexample + +In both cases, it is not necessary to include patterns for the many +logically equivalent RTL expressions. + +@cindex @code{xor}, canonicalization of +@item +The only possible RTL expressions involving both bitwise exclusive-or +and bitwise negation are @code{(xor:@var{m} @var{x} @var{y})} +and @code{(not:@var{m} (xor:@var{m} @var{x} @var{y}))}. + +@item +The sum of three items, one of which is a constant, will only appear in +the form + +@smallexample +(plus:@var{m} (plus:@var{m} @var{x} @var{y}) @var{constant}) +@end smallexample + +@item +On machines that do not use @code{cc0}, +@code{(compare @var{x} (const_int 0))} will be converted to +@var{x}. + +@cindex @code{zero_extract}, canonicalization of +@cindex @code{sign_extract}, canonicalization of +@item +Equality comparisons of a group of bits (usually a single bit) with zero +will be written using @code{zero_extract} rather than the equivalent +@code{and} or @code{sign_extract} operations. + +@end itemize + +Further canonicalization rules are defined in the function +@code{commutative_operand_precedence} in @file{gcc/rtlanal.c}. + +@end ifset +@ifset INTERNALS +@node Expander Definitions +@section Defining RTL Sequences for Code Generation +@cindex expander definitions +@cindex code generation RTL sequences +@cindex defining RTL sequences for code generation + +On some target machines, some standard pattern names for RTL generation +cannot be handled with single insn, but a sequence of RTL insns can +represent them. For these target machines, you can write a +@code{define_expand} to specify how to generate the sequence of RTL@. + +@findex define_expand +A @code{define_expand} is an RTL expression that looks almost like a +@code{define_insn}; but, unlike the latter, a @code{define_expand} is used +only for RTL generation and it can produce more than one RTL insn. + +A @code{define_expand} RTX has four operands: + +@itemize @bullet +@item +The name. Each @code{define_expand} must have a name, since the only +use for it is to refer to it by name. + +@item +The RTL template. This is a vector of RTL expressions representing +a sequence of separate instructions. Unlike @code{define_insn}, there +is no implicit surrounding @code{PARALLEL}. + +@item +The condition, a string containing a C expression. This expression is +used to express how the availability of this pattern depends on +subclasses of target machine, selected by command-line options when GCC +is run. This is just like the condition of a @code{define_insn} that +has a standard name. Therefore, the condition (if present) may not +depend on the data in the insn being matched, but only the +target-machine-type flags. The compiler needs to test these conditions +during initialization in order to learn exactly which named instructions +are available in a particular run. + +@item +The preparation statements, a string containing zero or more C +statements which are to be executed before RTL code is generated from +the RTL template. + +Usually these statements prepare temporary registers for use as +internal operands in the RTL template, but they can also generate RTL +insns directly by calling routines such as @code{emit_insn}, etc. +Any such insns precede the ones that come from the RTL template. +@end itemize + +Every RTL insn emitted by a @code{define_expand} must match some +@code{define_insn} in the machine description. Otherwise, the compiler +will crash when trying to generate code for the insn or trying to optimize +it. + +The RTL template, in addition to controlling generation of RTL insns, +also describes the operands that need to be specified when this pattern +is used. In particular, it gives a predicate for each operand. + +A true operand, which needs to be specified in order to generate RTL from +the pattern, should be described with a @code{match_operand} in its first +occurrence in the RTL template. This enters information on the operand's +predicate into the tables that record such things. GCC uses the +information to preload the operand into a register if that is required for +valid RTL code. If the operand is referred to more than once, subsequent +references should use @code{match_dup}. + +The RTL template may also refer to internal ``operands'' which are +temporary registers or labels used only within the sequence made by the +@code{define_expand}. Internal operands are substituted into the RTL +template with @code{match_dup}, never with @code{match_operand}. The +values of the internal operands are not passed in as arguments by the +compiler when it requests use of this pattern. Instead, they are computed +within the pattern, in the preparation statements. These statements +compute the values and store them into the appropriate elements of +@code{operands} so that @code{match_dup} can find them. + +There are two special macros defined for use in the preparation statements: +@code{DONE} and @code{FAIL}. Use them with a following semicolon, +as a statement. + +@table @code + +@findex DONE +@item DONE +Use the @code{DONE} macro to end RTL generation for the pattern. The +only RTL insns resulting from the pattern on this occasion will be +those already emitted by explicit calls to @code{emit_insn} within the +preparation statements; the RTL template will not be generated. + +@findex FAIL +@item FAIL +Make the pattern fail on this occasion. When a pattern fails, it means +that the pattern was not truly available. The calling routines in the +compiler will try other strategies for code generation using other patterns. + +Failure is currently supported only for binary (addition, multiplication, +shifting, etc.) and bit-field (@code{extv}, @code{extzv}, and @code{insv}) +operations. +@end table + +If the preparation falls through (invokes neither @code{DONE} nor +@code{FAIL}), then the @code{define_expand} acts like a +@code{define_insn} in that the RTL template is used to generate the +insn. + +The RTL template is not used for matching, only for generating the +initial insn list. If the preparation statement always invokes +@code{DONE} or @code{FAIL}, the RTL template may be reduced to a simple +list of operands, such as this example: + +@smallexample +@group +(define_expand "addsi3" + [(match_operand:SI 0 "register_operand" "") + (match_operand:SI 1 "register_operand" "") + (match_operand:SI 2 "register_operand" "")] +@end group +@group + "" + " +@{ + handle_add (operands[0], operands[1], operands[2]); + DONE; +@}") +@end group +@end smallexample + +Here is an example, the definition of left-shift for the SPUR chip: + +@smallexample +@group +(define_expand "ashlsi3" + [(set (match_operand:SI 0 "register_operand" "") + (ashift:SI +@end group +@group + (match_operand:SI 1 "register_operand" "") + (match_operand:SI 2 "nonmemory_operand" "")))] + "" + " +@end group +@end smallexample + +@smallexample +@group +@{ + if (GET_CODE (operands[2]) != CONST_INT + || (unsigned) INTVAL (operands[2]) > 3) + FAIL; +@}") +@end group +@end smallexample + +@noindent +This example uses @code{define_expand} so that it can generate an RTL insn +for shifting when the shift-count is in the supported range of 0 to 3 but +fail in other cases where machine insns aren't available. When it fails, +the compiler tries another strategy using different patterns (such as, a +library call). + +If the compiler were able to handle nontrivial condition-strings in +patterns with names, then it would be possible to use a +@code{define_insn} in that case. Here is another case (zero-extension +on the 68000) which makes more use of the power of @code{define_expand}: + +@smallexample +(define_expand "zero_extendhisi2" + [(set (match_operand:SI 0 "general_operand" "") + (const_int 0)) + (set (strict_low_part + (subreg:HI + (match_dup 0) + 0)) + (match_operand:HI 1 "general_operand" ""))] + "" + "operands[1] = make_safe_from (operands[1], operands[0]);") +@end smallexample + +@noindent +@findex make_safe_from +Here two RTL insns are generated, one to clear the entire output operand +and the other to copy the input operand into its low half. This sequence +is incorrect if the input operand refers to [the old value of] the output +operand, so the preparation statement makes sure this isn't so. The +function @code{make_safe_from} copies the @code{operands[1]} into a +temporary register if it refers to @code{operands[0]}. It does this +by emitting another RTL insn. + +Finally, a third example shows the use of an internal operand. +Zero-extension on the SPUR chip is done by @code{and}-ing the result +against a halfword mask. But this mask cannot be represented by a +@code{const_int} because the constant value is too large to be legitimate +on this machine. So it must be copied into a register with +@code{force_reg} and then the register used in the @code{and}. + +@smallexample +(define_expand "zero_extendhisi2" + [(set (match_operand:SI 0 "register_operand" "") + (and:SI (subreg:SI + (match_operand:HI 1 "register_operand" "") + 0) + (match_dup 2)))] + "" + "operands[2] + = force_reg (SImode, GEN_INT (65535)); ") +@end smallexample + +@emph{Note:} If the @code{define_expand} is used to serve a +standard binary or unary arithmetic operation or a bit-field operation, +then the last insn it generates must not be a @code{code_label}, +@code{barrier} or @code{note}. It must be an @code{insn}, +@code{jump_insn} or @code{call_insn}. If you don't need a real insn +at the end, emit an insn to copy the result of the operation into +itself. Such an insn will generate no code, but it can avoid problems +in the compiler. + +@end ifset +@ifset INTERNALS +@node Insn Splitting +@section Defining How to Split Instructions +@cindex insn splitting +@cindex instruction splitting +@cindex splitting instructions + +There are two cases where you should specify how to split a pattern +into multiple insns. On machines that have instructions requiring +delay slots (@pxref{Delay Slots}) or that have instructions whose +output is not available for multiple cycles (@pxref{Processor pipeline +description}), the compiler phases that optimize these cases need to +be able to move insns into one-instruction delay slots. However, some +insns may generate more than one machine instruction. These insns +cannot be placed into a delay slot. + +Often you can rewrite the single insn as a list of individual insns, +each corresponding to one machine instruction. The disadvantage of +doing so is that it will cause the compilation to be slower and require +more space. If the resulting insns are too complex, it may also +suppress some optimizations. The compiler splits the insn if there is a +reason to believe that it might improve instruction or delay slot +scheduling. + +The insn combiner phase also splits putative insns. If three insns are +merged into one insn with a complex expression that cannot be matched by +some @code{define_insn} pattern, the combiner phase attempts to split +the complex pattern into two insns that are recognized. Usually it can +break the complex pattern into two patterns by splitting out some +subexpression. However, in some other cases, such as performing an +addition of a large constant in two insns on a RISC machine, the way to +split the addition into two insns is machine-dependent. + +@findex define_split +The @code{define_split} definition tells the compiler how to split a +complex insn into several simpler insns. It looks like this: + +@smallexample +(define_split + [@var{insn-pattern}] + "@var{condition}" + [@var{new-insn-pattern-1} + @var{new-insn-pattern-2} + @dots{}] + "@var{preparation-statements}") +@end smallexample + +@var{insn-pattern} is a pattern that needs to be split and +@var{condition} is the final condition to be tested, as in a +@code{define_insn}. When an insn matching @var{insn-pattern} and +satisfying @var{condition} is found, it is replaced in the insn list +with the insns given by @var{new-insn-pattern-1}, +@var{new-insn-pattern-2}, etc. + +The @var{preparation-statements} are similar to those statements that +are specified for @code{define_expand} (@pxref{Expander Definitions}) +and are executed before the new RTL is generated to prepare for the +generated code or emit some insns whose pattern is not fixed. Unlike +those in @code{define_expand}, however, these statements must not +generate any new pseudo-registers. Once reload has completed, they also +must not allocate any space in the stack frame. + +Patterns are matched against @var{insn-pattern} in two different +circumstances. If an insn needs to be split for delay slot scheduling +or insn scheduling, the insn is already known to be valid, which means +that it must have been matched by some @code{define_insn} and, if +@code{reload_completed} is nonzero, is known to satisfy the constraints +of that @code{define_insn}. In that case, the new insn patterns must +also be insns that are matched by some @code{define_insn} and, if +@code{reload_completed} is nonzero, must also satisfy the constraints +of those definitions. + +As an example of this usage of @code{define_split}, consider the following +example from @file{a29k.md}, which splits a @code{sign_extend} from +@code{HImode} to @code{SImode} into a pair of shift insns: + +@smallexample +(define_split + [(set (match_operand:SI 0 "gen_reg_operand" "") + (sign_extend:SI (match_operand:HI 1 "gen_reg_operand" "")))] + "" + [(set (match_dup 0) + (ashift:SI (match_dup 1) + (const_int 16))) + (set (match_dup 0) + (ashiftrt:SI (match_dup 0) + (const_int 16)))] + " +@{ operands[1] = gen_lowpart (SImode, operands[1]); @}") +@end smallexample + +When the combiner phase tries to split an insn pattern, it is always the +case that the pattern is @emph{not} matched by any @code{define_insn}. +The combiner pass first tries to split a single @code{set} expression +and then the same @code{set} expression inside a @code{parallel}, but +followed by a @code{clobber} of a pseudo-reg to use as a scratch +register. In these cases, the combiner expects exactly two new insn +patterns to be generated. It will verify that these patterns match some +@code{define_insn} definitions, so you need not do this test in the +@code{define_split} (of course, there is no point in writing a +@code{define_split} that will never produce insns that match). + +Here is an example of this use of @code{define_split}, taken from +@file{rs6000.md}: + +@smallexample +(define_split + [(set (match_operand:SI 0 "gen_reg_operand" "") + (plus:SI (match_operand:SI 1 "gen_reg_operand" "") + (match_operand:SI 2 "non_add_cint_operand" "")))] + "" + [(set (match_dup 0) (plus:SI (match_dup 1) (match_dup 3))) + (set (match_dup 0) (plus:SI (match_dup 0) (match_dup 4)))] +" +@{ + int low = INTVAL (operands[2]) & 0xffff; + int high = (unsigned) INTVAL (operands[2]) >> 16; + + if (low & 0x8000) + high++, low |= 0xffff0000; + + operands[3] = GEN_INT (high << 16); + operands[4] = GEN_INT (low); +@}") +@end smallexample + +Here the predicate @code{non_add_cint_operand} matches any +@code{const_int} that is @emph{not} a valid operand of a single add +insn. The add with the smaller displacement is written so that it +can be substituted into the address of a subsequent operation. + +An example that uses a scratch register, from the same file, generates +an equality comparison of a register and a large constant: + +@smallexample +(define_split + [(set (match_operand:CC 0 "cc_reg_operand" "") + (compare:CC (match_operand:SI 1 "gen_reg_operand" "") + (match_operand:SI 2 "non_short_cint_operand" ""))) + (clobber (match_operand:SI 3 "gen_reg_operand" ""))] + "find_single_use (operands[0], insn, 0) + && (GET_CODE (*find_single_use (operands[0], insn, 0)) == EQ + || GET_CODE (*find_single_use (operands[0], insn, 0)) == NE)" + [(set (match_dup 3) (xor:SI (match_dup 1) (match_dup 4))) + (set (match_dup 0) (compare:CC (match_dup 3) (match_dup 5)))] + " +@{ + /* @r{Get the constant we are comparing against, C, and see what it + looks like sign-extended to 16 bits. Then see what constant + could be XOR'ed with C to get the sign-extended value.} */ + + int c = INTVAL (operands[2]); + int sextc = (c << 16) >> 16; + int xorv = c ^ sextc; + + operands[4] = GEN_INT (xorv); + operands[5] = GEN_INT (sextc); +@}") +@end smallexample + +To avoid confusion, don't write a single @code{define_split} that +accepts some insns that match some @code{define_insn} as well as some +insns that don't. Instead, write two separate @code{define_split} +definitions, one for the insns that are valid and one for the insns that +are not valid. + +The splitter is allowed to split jump instructions into sequence of +jumps or create new jumps in while splitting non-jump instructions. As +the central flowgraph and branch prediction information needs to be updated, +several restriction apply. + +Splitting of jump instruction into sequence that over by another jump +instruction is always valid, as compiler expect identical behavior of new +jump. When new sequence contains multiple jump instructions or new labels, +more assistance is needed. Splitter is required to create only unconditional +jumps, or simple conditional jump instructions. Additionally it must attach a +@code{REG_BR_PROB} note to each conditional jump. A global variable +@code{split_branch_probability} holds the probability of the original branch in case +it was an simple conditional jump, @minus{}1 otherwise. To simplify +recomputing of edge frequencies, the new sequence is required to have only +forward jumps to the newly created labels. + +@findex define_insn_and_split +For the common case where the pattern of a define_split exactly matches the +pattern of a define_insn, use @code{define_insn_and_split}. It looks like +this: + +@smallexample +(define_insn_and_split + [@var{insn-pattern}] + "@var{condition}" + "@var{output-template}" + "@var{split-condition}" + [@var{new-insn-pattern-1} + @var{new-insn-pattern-2} + @dots{}] + "@var{preparation-statements}" + [@var{insn-attributes}]) + +@end smallexample + +@var{insn-pattern}, @var{condition}, @var{output-template}, and +@var{insn-attributes} are used as in @code{define_insn}. The +@var{new-insn-pattern} vector and the @var{preparation-statements} are used as +in a @code{define_split}. The @var{split-condition} is also used as in +@code{define_split}, with the additional behavior that if the condition starts +with @samp{&&}, the condition used for the split will be the constructed as a +logical ``and'' of the split condition with the insn condition. For example, +from i386.md: + +@smallexample +(define_insn_and_split "zero_extendhisi2_and" + [(set (match_operand:SI 0 "register_operand" "=r") + (zero_extend:SI (match_operand:HI 1 "register_operand" "0"))) + (clobber (reg:CC 17))] + "TARGET_ZERO_EXTEND_WITH_AND && !optimize_size" + "#" + "&& reload_completed" + [(parallel [(set (match_dup 0) + (and:SI (match_dup 0) (const_int 65535))) + (clobber (reg:CC 17))])] + "" + [(set_attr "type" "alu1")]) + +@end smallexample + +In this case, the actual split condition will be +@samp{TARGET_ZERO_EXTEND_WITH_AND && !optimize_size && reload_completed}. + +The @code{define_insn_and_split} construction provides exactly the same +functionality as two separate @code{define_insn} and @code{define_split} +patterns. It exists for compactness, and as a maintenance tool to prevent +having to ensure the two patterns' templates match. + +@end ifset +@ifset INTERNALS +@node Including Patterns +@section Including Patterns in Machine Descriptions. +@cindex insn includes + +@findex include +The @code{include} pattern tells the compiler tools where to +look for patterns that are in files other than in the file +@file{.md}. This is used only at build time and there is no preprocessing allowed. + +It looks like: + +@smallexample + +(include + @var{pathname}) +@end smallexample + +For example: + +@smallexample + +(include "filestuff") + +@end smallexample + +Where @var{pathname} is a string that specifies the location of the file, +specifies the include file to be in @file{gcc/config/target/filestuff}. The +directory @file{gcc/config/target} is regarded as the default directory. + + +Machine descriptions may be split up into smaller more manageable subsections +and placed into subdirectories. + +By specifying: + +@smallexample + +(include "BOGUS/filestuff") + +@end smallexample + +the include file is specified to be in @file{gcc/config/@var{target}/BOGUS/filestuff}. + +Specifying an absolute path for the include file such as; +@smallexample + +(include "/u2/BOGUS/filestuff") + +@end smallexample +is permitted but is not encouraged. + +@subsection RTL Generation Tool Options for Directory Search +@cindex directory options .md +@cindex options, directory search +@cindex search options + +The @option{-I@var{dir}} option specifies directories to search for machine descriptions. +For example: + +@smallexample + +genrecog -I/p1/abc/proc1 -I/p2/abcd/pro2 target.md + +@end smallexample + + +Add the directory @var{dir} to the head of the list of directories to be +searched for header files. This can be used to override a system machine definition +file, substituting your own version, since these directories are +searched before the default machine description file directories. If you use more than +one @option{-I} option, the directories are scanned in left-to-right +order; the standard default directory come after. + + +@end ifset +@ifset INTERNALS +@node Peephole Definitions +@section Machine-Specific Peephole Optimizers +@cindex peephole optimizer definitions +@cindex defining peephole optimizers + +In addition to instruction patterns the @file{md} file may contain +definitions of machine-specific peephole optimizations. + +The combiner does not notice certain peephole optimizations when the data +flow in the program does not suggest that it should try them. For example, +sometimes two consecutive insns related in purpose can be combined even +though the second one does not appear to use a register computed in the +first one. A machine-specific peephole optimizer can detect such +opportunities. + +There are two forms of peephole definitions that may be used. The +original @code{define_peephole} is run at assembly output time to +match insns and substitute assembly text. Use of @code{define_peephole} +is deprecated. + +A newer @code{define_peephole2} matches insns and substitutes new +insns. The @code{peephole2} pass is run after register allocation +but before scheduling, which may result in much better code for +targets that do scheduling. + +@menu +* define_peephole:: RTL to Text Peephole Optimizers +* define_peephole2:: RTL to RTL Peephole Optimizers +@end menu + +@end ifset +@ifset INTERNALS +@node define_peephole +@subsection RTL to Text Peephole Optimizers +@findex define_peephole + +@need 1000 +A definition looks like this: + +@smallexample +(define_peephole + [@var{insn-pattern-1} + @var{insn-pattern-2} + @dots{}] + "@var{condition}" + "@var{template}" + "@var{optional-insn-attributes}") +@end smallexample + +@noindent +The last string operand may be omitted if you are not using any +machine-specific information in this machine description. If present, +it must obey the same rules as in a @code{define_insn}. + +In this skeleton, @var{insn-pattern-1} and so on are patterns to match +consecutive insns. The optimization applies to a sequence of insns when +@var{insn-pattern-1} matches the first one, @var{insn-pattern-2} matches +the next, and so on. + +Each of the insns matched by a peephole must also match a +@code{define_insn}. Peepholes are checked only at the last stage just +before code generation, and only optionally. Therefore, any insn which +would match a peephole but no @code{define_insn} will cause a crash in code +generation in an unoptimized compilation, or at various optimization +stages. + +The operands of the insns are matched with @code{match_operands}, +@code{match_operator}, and @code{match_dup}, as usual. What is not +usual is that the operand numbers apply to all the insn patterns in the +definition. So, you can check for identical operands in two insns by +using @code{match_operand} in one insn and @code{match_dup} in the +other. + +The operand constraints used in @code{match_operand} patterns do not have +any direct effect on the applicability of the peephole, but they will +be validated afterward, so make sure your constraints are general enough +to apply whenever the peephole matches. If the peephole matches +but the constraints are not satisfied, the compiler will crash. + +It is safe to omit constraints in all the operands of the peephole; or +you can write constraints which serve as a double-check on the criteria +previously tested. + +Once a sequence of insns matches the patterns, the @var{condition} is +checked. This is a C expression which makes the final decision whether to +perform the optimization (we do so if the expression is nonzero). If +@var{condition} is omitted (in other words, the string is empty) then the +optimization is applied to every sequence of insns that matches the +patterns. + +The defined peephole optimizations are applied after register allocation +is complete. Therefore, the peephole definition can check which +operands have ended up in which kinds of registers, just by looking at +the operands. + +@findex prev_active_insn +The way to refer to the operands in @var{condition} is to write +@code{operands[@var{i}]} for operand number @var{i} (as matched by +@code{(match_operand @var{i} @dots{})}). Use the variable @code{insn} +to refer to the last of the insns being matched; use +@code{prev_active_insn} to find the preceding insns. + +@findex dead_or_set_p +When optimizing computations with intermediate results, you can use +@var{condition} to match only when the intermediate results are not used +elsewhere. Use the C expression @code{dead_or_set_p (@var{insn}, +@var{op})}, where @var{insn} is the insn in which you expect the value +to be used for the last time (from the value of @code{insn}, together +with use of @code{prev_nonnote_insn}), and @var{op} is the intermediate +value (from @code{operands[@var{i}]}). + +Applying the optimization means replacing the sequence of insns with one +new insn. The @var{template} controls ultimate output of assembler code +for this combined insn. It works exactly like the template of a +@code{define_insn}. Operand numbers in this template are the same ones +used in matching the original sequence of insns. + +The result of a defined peephole optimizer does not need to match any of +the insn patterns in the machine description; it does not even have an +opportunity to match them. The peephole optimizer definition itself serves +as the insn pattern to control how the insn is output. + +Defined peephole optimizers are run as assembler code is being output, +so the insns they produce are never combined or rearranged in any way. + +Here is an example, taken from the 68000 machine description: + +@smallexample +(define_peephole + [(set (reg:SI 15) (plus:SI (reg:SI 15) (const_int 4))) + (set (match_operand:DF 0 "register_operand" "=f") + (match_operand:DF 1 "register_operand" "ad"))] + "FP_REG_P (operands[0]) && ! FP_REG_P (operands[1])" +@{ + rtx xoperands[2]; + xoperands[1] = gen_rtx_REG (SImode, REGNO (operands[1]) + 1); +#ifdef MOTOROLA + output_asm_insn ("move.l %1,(sp)", xoperands); + output_asm_insn ("move.l %1,-(sp)", operands); + return "fmove.d (sp)+,%0"; +#else + output_asm_insn ("movel %1,sp@@", xoperands); + output_asm_insn ("movel %1,sp@@-", operands); + return "fmoved sp@@+,%0"; +#endif +@}) +@end smallexample + +@need 1000 +The effect of this optimization is to change + +@smallexample +@group +jbsr _foobar +addql #4,sp +movel d1,sp@@- +movel d0,sp@@- +fmoved sp@@+,fp0 +@end group +@end smallexample + +@noindent +into + +@smallexample +@group +jbsr _foobar +movel d1,sp@@ +movel d0,sp@@- +fmoved sp@@+,fp0 +@end group +@end smallexample + +@ignore +@findex CC_REVERSED +If a peephole matches a sequence including one or more jump insns, you must +take account of the flags such as @code{CC_REVERSED} which specify that the +condition codes are represented in an unusual manner. The compiler +automatically alters any ordinary conditional jumps which occur in such +situations, but the compiler cannot alter jumps which have been replaced by +peephole optimizations. So it is up to you to alter the assembler code +that the peephole produces. Supply C code to write the assembler output, +and in this C code check the condition code status flags and change the +assembler code as appropriate. +@end ignore + +@var{insn-pattern-1} and so on look @emph{almost} like the second +operand of @code{define_insn}. There is one important difference: the +second operand of @code{define_insn} consists of one or more RTX's +enclosed in square brackets. Usually, there is only one: then the same +action can be written as an element of a @code{define_peephole}. But +when there are multiple actions in a @code{define_insn}, they are +implicitly enclosed in a @code{parallel}. Then you must explicitly +write the @code{parallel}, and the square brackets within it, in the +@code{define_peephole}. Thus, if an insn pattern looks like this, + +@smallexample +(define_insn "divmodsi4" + [(set (match_operand:SI 0 "general_operand" "=d") + (div:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "dmsK"))) + (set (match_operand:SI 3 "general_operand" "=d") + (mod:SI (match_dup 1) (match_dup 2)))] + "TARGET_68020" + "divsl%.l %2,%3:%0") +@end smallexample + +@noindent +then the way to mention this insn in a peephole is as follows: + +@smallexample +(define_peephole + [@dots{} + (parallel + [(set (match_operand:SI 0 "general_operand" "=d") + (div:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "dmsK"))) + (set (match_operand:SI 3 "general_operand" "=d") + (mod:SI (match_dup 1) (match_dup 2)))]) + @dots{}] + @dots{}) +@end smallexample + +@end ifset +@ifset INTERNALS +@node define_peephole2 +@subsection RTL to RTL Peephole Optimizers +@findex define_peephole2 + +The @code{define_peephole2} definition tells the compiler how to +substitute one sequence of instructions for another sequence, +what additional scratch registers may be needed and what their +lifetimes must be. + +@smallexample +(define_peephole2 + [@var{insn-pattern-1} + @var{insn-pattern-2} + @dots{}] + "@var{condition}" + [@var{new-insn-pattern-1} + @var{new-insn-pattern-2} + @dots{}] + "@var{preparation-statements}") +@end smallexample + +The definition is almost identical to @code{define_split} +(@pxref{Insn Splitting}) except that the pattern to match is not a +single instruction, but a sequence of instructions. + +It is possible to request additional scratch registers for use in the +output template. If appropriate registers are not free, the pattern +will simply not match. + +@findex match_scratch +@findex match_dup +Scratch registers are requested with a @code{match_scratch} pattern at +the top level of the input pattern. The allocated register (initially) will +be dead at the point requested within the original sequence. If the scratch +is used at more than a single point, a @code{match_dup} pattern at the +top level of the input pattern marks the last position in the input sequence +at which the register must be available. + +Here is an example from the IA-32 machine description: + +@smallexample +(define_peephole2 + [(match_scratch:SI 2 "r") + (parallel [(set (match_operand:SI 0 "register_operand" "") + (match_operator:SI 3 "arith_or_logical_operator" + [(match_dup 0) + (match_operand:SI 1 "memory_operand" "")])) + (clobber (reg:CC 17))])] + "! optimize_size && ! TARGET_READ_MODIFY" + [(set (match_dup 2) (match_dup 1)) + (parallel [(set (match_dup 0) + (match_op_dup 3 [(match_dup 0) (match_dup 2)])) + (clobber (reg:CC 17))])] + "") +@end smallexample + +@noindent +This pattern tries to split a load from its use in the hopes that we'll be +able to schedule around the memory load latency. It allocates a single +@code{SImode} register of class @code{GENERAL_REGS} (@code{"r"}) that needs +to be live only at the point just before the arithmetic. + +A real example requiring extended scratch lifetimes is harder to come by, +so here's a silly made-up example: + +@smallexample +(define_peephole2 + [(match_scratch:SI 4 "r") + (set (match_operand:SI 0 "" "") (match_operand:SI 1 "" "")) + (set (match_operand:SI 2 "" "") (match_dup 1)) + (match_dup 4) + (set (match_operand:SI 3 "" "") (match_dup 1))] + "/* @r{determine 1 does not overlap 0 and 2} */" + [(set (match_dup 4) (match_dup 1)) + (set (match_dup 0) (match_dup 4)) + (set (match_dup 2) (match_dup 4))] + (set (match_dup 3) (match_dup 4))] + "") +@end smallexample + +@noindent +If we had not added the @code{(match_dup 4)} in the middle of the input +sequence, it might have been the case that the register we chose at the +beginning of the sequence is killed by the first or second @code{set}. + +@end ifset +@ifset INTERNALS +@node Insn Attributes +@section Instruction Attributes +@cindex insn attributes +@cindex instruction attributes + +In addition to describing the instruction supported by the target machine, +the @file{md} file also defines a group of @dfn{attributes} and a set of +values for each. Every generated insn is assigned a value for each attribute. +One possible attribute would be the effect that the insn has on the machine's +condition code. This attribute can then be used by @code{NOTICE_UPDATE_CC} +to track the condition codes. + +@menu +* Defining Attributes:: Specifying attributes and their values. +* Expressions:: Valid expressions for attribute values. +* Tagging Insns:: Assigning attribute values to insns. +* Attr Example:: An example of assigning attributes. +* Insn Lengths:: Computing the length of insns. +* Constant Attributes:: Defining attributes that are constant. +* Delay Slots:: Defining delay slots required for a machine. +* Processor pipeline description:: Specifying information for insn scheduling. +@end menu + +@end ifset +@ifset INTERNALS +@node Defining Attributes +@subsection Defining Attributes and their Values +@cindex defining attributes and their values +@cindex attributes, defining + +@findex define_attr +The @code{define_attr} expression is used to define each attribute required +by the target machine. It looks like: + +@smallexample +(define_attr @var{name} @var{list-of-values} @var{default}) +@end smallexample + +@var{name} is a string specifying the name of the attribute being defined. + +@var{list-of-values} is either a string that specifies a comma-separated +list of values that can be assigned to the attribute, or a null string to +indicate that the attribute takes numeric values. + +@var{default} is an attribute expression that gives the value of this +attribute for insns that match patterns whose definition does not include +an explicit value for this attribute. @xref{Attr Example}, for more +information on the handling of defaults. @xref{Constant Attributes}, +for information on attributes that do not depend on any particular insn. + +@findex insn-attr.h +For each defined attribute, a number of definitions are written to the +@file{insn-attr.h} file. For cases where an explicit set of values is +specified for an attribute, the following are defined: + +@itemize @bullet +@item +A @samp{#define} is written for the symbol @samp{HAVE_ATTR_@var{name}}. + +@item +An enumerated class is defined for @samp{attr_@var{name}} with +elements of the form @samp{@var{upper-name}_@var{upper-value}} where +the attribute name and value are first converted to uppercase. + +@item +A function @samp{get_attr_@var{name}} is defined that is passed an insn and +returns the attribute value for that insn. +@end itemize + +For example, if the following is present in the @file{md} file: + +@smallexample +(define_attr "type" "branch,fp,load,store,arith" @dots{}) +@end smallexample + +@noindent +the following lines will be written to the file @file{insn-attr.h}. + +@smallexample +#define HAVE_ATTR_type +enum attr_type @{TYPE_BRANCH, TYPE_FP, TYPE_LOAD, + TYPE_STORE, TYPE_ARITH@}; +extern enum attr_type get_attr_type (); +@end smallexample + +If the attribute takes numeric values, no @code{enum} type will be +defined and the function to obtain the attribute's value will return +@code{int}. + +@end ifset +@ifset INTERNALS +@node Expressions +@subsection Attribute Expressions +@cindex attribute expressions + +RTL expressions used to define attributes use the codes described above +plus a few specific to attribute definitions, to be discussed below. +Attribute value expressions must have one of the following forms: + +@table @code +@cindex @code{const_int} and attributes +@item (const_int @var{i}) +The integer @var{i} specifies the value of a numeric attribute. @var{i} +must be non-negative. + +The value of a numeric attribute can be specified either with a +@code{const_int}, or as an integer represented as a string in +@code{const_string}, @code{eq_attr} (see below), @code{attr}, +@code{symbol_ref}, simple arithmetic expressions, and @code{set_attr} +overrides on specific instructions (@pxref{Tagging Insns}). + +@cindex @code{const_string} and attributes +@item (const_string @var{value}) +The string @var{value} specifies a constant attribute value. +If @var{value} is specified as @samp{"*"}, it means that the default value of +the attribute is to be used for the insn containing this expression. +@samp{"*"} obviously cannot be used in the @var{default} expression +of a @code{define_attr}. + +If the attribute whose value is being specified is numeric, @var{value} +must be a string containing a non-negative integer (normally +@code{const_int} would be used in this case). Otherwise, it must +contain one of the valid values for the attribute. + +@cindex @code{if_then_else} and attributes +@item (if_then_else @var{test} @var{true-value} @var{false-value}) +@var{test} specifies an attribute test, whose format is defined below. +The value of this expression is @var{true-value} if @var{test} is true, +otherwise it is @var{false-value}. + +@cindex @code{cond} and attributes +@item (cond [@var{test1} @var{value1} @dots{}] @var{default}) +The first operand of this expression is a vector containing an even +number of expressions and consisting of pairs of @var{test} and @var{value} +expressions. The value of the @code{cond} expression is that of the +@var{value} corresponding to the first true @var{test} expression. If +none of the @var{test} expressions are true, the value of the @code{cond} +expression is that of the @var{default} expression. +@end table + +@var{test} expressions can have one of the following forms: + +@table @code +@cindex @code{const_int} and attribute tests +@item (const_int @var{i}) +This test is true if @var{i} is nonzero and false otherwise. + +@cindex @code{not} and attributes +@cindex @code{ior} and attributes +@cindex @code{and} and attributes +@item (not @var{test}) +@itemx (ior @var{test1} @var{test2}) +@itemx (and @var{test1} @var{test2}) +These tests are true if the indicated logical function is true. + +@cindex @code{match_operand} and attributes +@item (match_operand:@var{m} @var{n} @var{pred} @var{constraints}) +This test is true if operand @var{n} of the insn whose attribute value +is being determined has mode @var{m} (this part of the test is ignored +if @var{m} is @code{VOIDmode}) and the function specified by the string +@var{pred} returns a nonzero value when passed operand @var{n} and mode +@var{m} (this part of the test is ignored if @var{pred} is the null +string). + +The @var{constraints} operand is ignored and should be the null string. + +@cindex @code{le} and attributes +@cindex @code{leu} and attributes +@cindex @code{lt} and attributes +@cindex @code{gt} and attributes +@cindex @code{gtu} and attributes +@cindex @code{ge} and attributes +@cindex @code{geu} and attributes +@cindex @code{ne} and attributes +@cindex @code{eq} and attributes +@cindex @code{plus} and attributes +@cindex @code{minus} and attributes +@cindex @code{mult} and attributes +@cindex @code{div} and attributes +@cindex @code{mod} and attributes +@cindex @code{abs} and attributes +@cindex @code{neg} and attributes +@cindex @code{ashift} and attributes +@cindex @code{lshiftrt} and attributes +@cindex @code{ashiftrt} and attributes +@item (le @var{arith1} @var{arith2}) +@itemx (leu @var{arith1} @var{arith2}) +@itemx (lt @var{arith1} @var{arith2}) +@itemx (ltu @var{arith1} @var{arith2}) +@itemx (gt @var{arith1} @var{arith2}) +@itemx (gtu @var{arith1} @var{arith2}) +@itemx (ge @var{arith1} @var{arith2}) +@itemx (geu @var{arith1} @var{arith2}) +@itemx (ne @var{arith1} @var{arith2}) +@itemx (eq @var{arith1} @var{arith2}) +These tests are true if the indicated comparison of the two arithmetic +expressions is true. Arithmetic expressions are formed with +@code{plus}, @code{minus}, @code{mult}, @code{div}, @code{mod}, +@code{abs}, @code{neg}, @code{and}, @code{ior}, @code{xor}, @code{not}, +@code{ashift}, @code{lshiftrt}, and @code{ashiftrt} expressions. + +@findex get_attr +@code{const_int} and @code{symbol_ref} are always valid terms (@pxref{Insn +Lengths},for additional forms). @code{symbol_ref} is a string +denoting a C expression that yields an @code{int} when evaluated by the +@samp{get_attr_@dots{}} routine. It should normally be a global +variable. + +@findex eq_attr +@item (eq_attr @var{name} @var{value}) +@var{name} is a string specifying the name of an attribute. + +@var{value} is a string that is either a valid value for attribute +@var{name}, a comma-separated list of values, or @samp{!} followed by a +value or list. If @var{value} does not begin with a @samp{!}, this +test is true if the value of the @var{name} attribute of the current +insn is in the list specified by @var{value}. If @var{value} begins +with a @samp{!}, this test is true if the attribute's value is +@emph{not} in the specified list. + +For example, + +@smallexample +(eq_attr "type" "load,store") +@end smallexample + +@noindent +is equivalent to + +@smallexample +(ior (eq_attr "type" "load") (eq_attr "type" "store")) +@end smallexample + +If @var{name} specifies an attribute of @samp{alternative}, it refers to the +value of the compiler variable @code{which_alternative} +(@pxref{Output Statement}) and the values must be small integers. For +example, + +@smallexample +(eq_attr "alternative" "2,3") +@end smallexample + +@noindent +is equivalent to + +@smallexample +(ior (eq (symbol_ref "which_alternative") (const_int 2)) + (eq (symbol_ref "which_alternative") (const_int 3))) +@end smallexample + +Note that, for most attributes, an @code{eq_attr} test is simplified in cases +where the value of the attribute being tested is known for all insns matching +a particular pattern. This is by far the most common case. + +@findex attr_flag +@item (attr_flag @var{name}) +The value of an @code{attr_flag} expression is true if the flag +specified by @var{name} is true for the @code{insn} currently being +scheduled. + +@var{name} is a string specifying one of a fixed set of flags to test. +Test the flags @code{forward} and @code{backward} to determine the +direction of a conditional branch. Test the flags @code{very_likely}, +@code{likely}, @code{very_unlikely}, and @code{unlikely} to determine +if a conditional branch is expected to be taken. + +If the @code{very_likely} flag is true, then the @code{likely} flag is also +true. Likewise for the @code{very_unlikely} and @code{unlikely} flags. + +This example describes a conditional branch delay slot which +can be nullified for forward branches that are taken (annul-true) or +for backward branches which are not taken (annul-false). + +@smallexample +(define_delay (eq_attr "type" "cbranch") + [(eq_attr "in_branch_delay" "true") + (and (eq_attr "in_branch_delay" "true") + (attr_flag "forward")) + (and (eq_attr "in_branch_delay" "true") + (attr_flag "backward"))]) +@end smallexample + +The @code{forward} and @code{backward} flags are false if the current +@code{insn} being scheduled is not a conditional branch. + +The @code{very_likely} and @code{likely} flags are true if the +@code{insn} being scheduled is not a conditional branch. +The @code{very_unlikely} and @code{unlikely} flags are false if the +@code{insn} being scheduled is not a conditional branch. + +@code{attr_flag} is only used during delay slot scheduling and has no +meaning to other passes of the compiler. + +@findex attr +@item (attr @var{name}) +The value of another attribute is returned. This is most useful +for numeric attributes, as @code{eq_attr} and @code{attr_flag} +produce more efficient code for non-numeric attributes. +@end table + +@end ifset +@ifset INTERNALS +@node Tagging Insns +@subsection Assigning Attribute Values to Insns +@cindex tagging insns +@cindex assigning attribute values to insns + +The value assigned to an attribute of an insn is primarily determined by +which pattern is matched by that insn (or which @code{define_peephole} +generated it). Every @code{define_insn} and @code{define_peephole} can +have an optional last argument to specify the values of attributes for +matching insns. The value of any attribute not specified in a particular +insn is set to the default value for that attribute, as specified in its +@code{define_attr}. Extensive use of default values for attributes +permits the specification of the values for only one or two attributes +in the definition of most insn patterns, as seen in the example in the +next section. + +The optional last argument of @code{define_insn} and +@code{define_peephole} is a vector of expressions, each of which defines +the value for a single attribute. The most general way of assigning an +attribute's value is to use a @code{set} expression whose first operand is an +@code{attr} expression giving the name of the attribute being set. The +second operand of the @code{set} is an attribute expression +(@pxref{Expressions}) giving the value of the attribute. + +When the attribute value depends on the @samp{alternative} attribute +(i.e., which is the applicable alternative in the constraint of the +insn), the @code{set_attr_alternative} expression can be used. It +allows the specification of a vector of attribute expressions, one for +each alternative. + +@findex set_attr +When the generality of arbitrary attribute expressions is not required, +the simpler @code{set_attr} expression can be used, which allows +specifying a string giving either a single attribute value or a list +of attribute values, one for each alternative. + +The form of each of the above specifications is shown below. In each case, +@var{name} is a string specifying the attribute to be set. + +@table @code +@item (set_attr @var{name} @var{value-string}) +@var{value-string} is either a string giving the desired attribute value, +or a string containing a comma-separated list giving the values for +succeeding alternatives. The number of elements must match the number +of alternatives in the constraint of the insn pattern. + +Note that it may be useful to specify @samp{*} for some alternative, in +which case the attribute will assume its default value for insns matching +that alternative. + +@findex set_attr_alternative +@item (set_attr_alternative @var{name} [@var{value1} @var{value2} @dots{}]) +Depending on the alternative of the insn, the value will be one of the +specified values. This is a shorthand for using a @code{cond} with +tests on the @samp{alternative} attribute. + +@findex attr +@item (set (attr @var{name}) @var{value}) +The first operand of this @code{set} must be the special RTL expression +@code{attr}, whose sole operand is a string giving the name of the +attribute being set. @var{value} is the value of the attribute. +@end table + +The following shows three different ways of representing the same +attribute value specification: + +@smallexample +(set_attr "type" "load,store,arith") + +(set_attr_alternative "type" + [(const_string "load") (const_string "store") + (const_string "arith")]) + +(set (attr "type") + (cond [(eq_attr "alternative" "1") (const_string "load") + (eq_attr "alternative" "2") (const_string "store")] + (const_string "arith"))) +@end smallexample + +@need 1000 +@findex define_asm_attributes +The @code{define_asm_attributes} expression provides a mechanism to +specify the attributes assigned to insns produced from an @code{asm} +statement. It has the form: + +@smallexample +(define_asm_attributes [@var{attr-sets}]) +@end smallexample + +@noindent +where @var{attr-sets} is specified the same as for both the +@code{define_insn} and the @code{define_peephole} expressions. + +These values will typically be the ``worst case'' attribute values. For +example, they might indicate that the condition code will be clobbered. + +A specification for a @code{length} attribute is handled specially. The +way to compute the length of an @code{asm} insn is to multiply the +length specified in the expression @code{define_asm_attributes} by the +number of machine instructions specified in the @code{asm} statement, +determined by counting the number of semicolons and newlines in the +string. Therefore, the value of the @code{length} attribute specified +in a @code{define_asm_attributes} should be the maximum possible length +of a single machine instruction. + +@end ifset +@ifset INTERNALS +@node Attr Example +@subsection Example of Attribute Specifications +@cindex attribute specifications example +@cindex attribute specifications + +The judicious use of defaulting is important in the efficient use of +insn attributes. Typically, insns are divided into @dfn{types} and an +attribute, customarily called @code{type}, is used to represent this +value. This attribute is normally used only to define the default value +for other attributes. An example will clarify this usage. + +Assume we have a RISC machine with a condition code and in which only +full-word operations are performed in registers. Let us assume that we +can divide all insns into loads, stores, (integer) arithmetic +operations, floating point operations, and branches. + +Here we will concern ourselves with determining the effect of an insn on +the condition code and will limit ourselves to the following possible +effects: The condition code can be set unpredictably (clobbered), not +be changed, be set to agree with the results of the operation, or only +changed if the item previously set into the condition code has been +modified. + +Here is part of a sample @file{md} file for such a machine: + +@smallexample +(define_attr "type" "load,store,arith,fp,branch" (const_string "arith")) + +(define_attr "cc" "clobber,unchanged,set,change0" + (cond [(eq_attr "type" "load") + (const_string "change0") + (eq_attr "type" "store,branch") + (const_string "unchanged") + (eq_attr "type" "arith") + (if_then_else (match_operand:SI 0 "" "") + (const_string "set") + (const_string "clobber"))] + (const_string "clobber"))) + +(define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,r,m") + (match_operand:SI 1 "general_operand" "r,m,r"))] + "" + "@@ + move %0,%1 + load %0,%1 + store %0,%1" + [(set_attr "type" "arith,load,store")]) +@end smallexample + +Note that we assume in the above example that arithmetic operations +performed on quantities smaller than a machine word clobber the condition +code since they will set the condition code to a value corresponding to the +full-word result. + +@end ifset +@ifset INTERNALS +@node Insn Lengths +@subsection Computing the Length of an Insn +@cindex insn lengths, computing +@cindex computing the length of an insn + +For many machines, multiple types of branch instructions are provided, each +for different length branch displacements. In most cases, the assembler +will choose the correct instruction to use. However, when the assembler +cannot do so, GCC can when a special attribute, the @code{length} +attribute, is defined. This attribute must be defined to have numeric +values by specifying a null string in its @code{define_attr}. + +In the case of the @code{length} attribute, two additional forms of +arithmetic terms are allowed in test expressions: + +@table @code +@cindex @code{match_dup} and attributes +@item (match_dup @var{n}) +This refers to the address of operand @var{n} of the current insn, which +must be a @code{label_ref}. + +@cindex @code{pc} and attributes +@item (pc) +This refers to the address of the @emph{current} insn. It might have +been more consistent with other usage to make this the address of the +@emph{next} insn but this would be confusing because the length of the +current insn is to be computed. +@end table + +@cindex @code{addr_vec}, length of +@cindex @code{addr_diff_vec}, length of +For normal insns, the length will be determined by value of the +@code{length} attribute. In the case of @code{addr_vec} and +@code{addr_diff_vec} insn patterns, the length is computed as +the number of vectors multiplied by the size of each vector. + +Lengths are measured in addressable storage units (bytes). + +The following macros can be used to refine the length computation: + +@table @code +@findex ADJUST_INSN_LENGTH +@item ADJUST_INSN_LENGTH (@var{insn}, @var{length}) +If defined, modifies the length assigned to instruction @var{insn} as a +function of the context in which it is used. @var{length} is an lvalue +that contains the initially computed length of the insn and should be +updated with the correct length of the insn. + +This macro will normally not be required. A case in which it is +required is the ROMP@. On this machine, the size of an @code{addr_vec} +insn must be increased by two to compensate for the fact that alignment +may be required. +@end table + +@findex get_attr_length +The routine that returns @code{get_attr_length} (the value of the +@code{length} attribute) can be used by the output routine to +determine the form of the branch instruction to be written, as the +example below illustrates. + +As an example of the specification of variable-length branches, consider +the IBM 360. If we adopt the convention that a register will be set to +the starting address of a function, we can jump to labels within 4k of +the start using a four-byte instruction. Otherwise, we need a six-byte +sequence to load the address from memory and then branch to it. + +On such a machine, a pattern for a branch instruction might be specified +as follows: + +@smallexample +(define_insn "jump" + [(set (pc) + (label_ref (match_operand 0 "" "")))] + "" +@{ + return (get_attr_length (insn) == 4 + ? "b %l0" : "l r15,=a(%l0); br r15"); +@} + [(set (attr "length") + (if_then_else (lt (match_dup 0) (const_int 4096)) + (const_int 4) + (const_int 6)))]) +@end smallexample + +@end ifset +@ifset INTERNALS +@node Constant Attributes +@subsection Constant Attributes +@cindex constant attributes + +A special form of @code{define_attr}, where the expression for the +default value is a @code{const} expression, indicates an attribute that +is constant for a given run of the compiler. Constant attributes may be +used to specify which variety of processor is used. For example, + +@smallexample +(define_attr "cpu" "m88100,m88110,m88000" + (const + (cond [(symbol_ref "TARGET_88100") (const_string "m88100") + (symbol_ref "TARGET_88110") (const_string "m88110")] + (const_string "m88000")))) + +(define_attr "memory" "fast,slow" + (const + (if_then_else (symbol_ref "TARGET_FAST_MEM") + (const_string "fast") + (const_string "slow")))) +@end smallexample + +The routine generated for constant attributes has no parameters as it +does not depend on any particular insn. RTL expressions used to define +the value of a constant attribute may use the @code{symbol_ref} form, +but may not use either the @code{match_operand} form or @code{eq_attr} +forms involving insn attributes. + +@end ifset +@ifset INTERNALS +@node Delay Slots +@subsection Delay Slot Scheduling +@cindex delay slots, defining + +The insn attribute mechanism can be used to specify the requirements for +delay slots, if any, on a target machine. An instruction is said to +require a @dfn{delay slot} if some instructions that are physically +after the instruction are executed as if they were located before it. +Classic examples are branch and call instructions, which often execute +the following instruction before the branch or call is performed. + +On some machines, conditional branch instructions can optionally +@dfn{annul} instructions in the delay slot. This means that the +instruction will not be executed for certain branch outcomes. Both +instructions that annul if the branch is true and instructions that +annul if the branch is false are supported. + +Delay slot scheduling differs from instruction scheduling in that +determining whether an instruction needs a delay slot is dependent only +on the type of instruction being generated, not on data flow between the +instructions. See the next section for a discussion of data-dependent +instruction scheduling. + +@findex define_delay +The requirement of an insn needing one or more delay slots is indicated +via the @code{define_delay} expression. It has the following form: + +@smallexample +(define_delay @var{test} + [@var{delay-1} @var{annul-true-1} @var{annul-false-1} + @var{delay-2} @var{annul-true-2} @var{annul-false-2} + @dots{}]) +@end smallexample + +@var{test} is an attribute test that indicates whether this +@code{define_delay} applies to a particular insn. If so, the number of +required delay slots is determined by the length of the vector specified +as the second argument. An insn placed in delay slot @var{n} must +satisfy attribute test @var{delay-n}. @var{annul-true-n} is an +attribute test that specifies which insns may be annulled if the branch +is true. Similarly, @var{annul-false-n} specifies which insns in the +delay slot may be annulled if the branch is false. If annulling is not +supported for that delay slot, @code{(nil)} should be coded. + +For example, in the common case where branch and call insns require +a single delay slot, which may contain any insn other than a branch or +call, the following would be placed in the @file{md} file: + +@smallexample +(define_delay (eq_attr "type" "branch,call") + [(eq_attr "type" "!branch,call") (nil) (nil)]) +@end smallexample + +Multiple @code{define_delay} expressions may be specified. In this +case, each such expression specifies different delay slot requirements +and there must be no insn for which tests in two @code{define_delay} +expressions are both true. + +For example, if we have a machine that requires one delay slot for branches +but two for calls, no delay slot can contain a branch or call insn, +and any valid insn in the delay slot for the branch can be annulled if the +branch is true, we might represent this as follows: + +@smallexample +(define_delay (eq_attr "type" "branch") + [(eq_attr "type" "!branch,call") + (eq_attr "type" "!branch,call") + (nil)]) + +(define_delay (eq_attr "type" "call") + [(eq_attr "type" "!branch,call") (nil) (nil) + (eq_attr "type" "!branch,call") (nil) (nil)]) +@end smallexample +@c the above is *still* too long. --mew 4feb93 + +@end ifset +@ifset INTERNALS +@node Processor pipeline description +@subsection Specifying processor pipeline description +@cindex processor pipeline description +@cindex processor functional units +@cindex instruction latency time +@cindex interlock delays +@cindex data dependence delays +@cindex reservation delays +@cindex pipeline hazard recognizer +@cindex automaton based pipeline description +@cindex regular expressions +@cindex deterministic finite state automaton +@cindex automaton based scheduler +@cindex RISC +@cindex VLIW + +To achieve better performance, most modern processors +(super-pipelined, superscalar @acronym{RISC}, and @acronym{VLIW} +processors) have many @dfn{functional units} on which several +instructions can be executed simultaneously. An instruction starts +execution if its issue conditions are satisfied. If not, the +instruction is stalled until its conditions are satisfied. Such +@dfn{interlock (pipeline) delay} causes interruption of the fetching +of successor instructions (or demands nop instructions, e.g.@: for some +MIPS processors). + +There are two major kinds of interlock delays in modern processors. +The first one is a data dependence delay determining @dfn{instruction +latency time}. The instruction execution is not started until all +source data have been evaluated by prior instructions (there are more +complex cases when the instruction execution starts even when the data +are not available but will be ready in given time after the +instruction execution start). Taking the data dependence delays into +account is simple. The data dependence (true, output, and +anti-dependence) delay between two instructions is given by a +constant. In most cases this approach is adequate. The second kind +of interlock delays is a reservation delay. The reservation delay +means that two instructions under execution will be in need of shared +processors resources, i.e.@: buses, internal registers, and/or +functional units, which are reserved for some time. Taking this kind +of delay into account is complex especially for modern @acronym{RISC} +processors. + +The task of exploiting more processor parallelism is solved by an +instruction scheduler. For a better solution to this problem, the +instruction scheduler has to have an adequate description of the +processor parallelism (or @dfn{pipeline description}). GCC +machine descriptions describe processor parallelism and functional +unit reservations for groups of instructions with the aid of +@dfn{regular expressions}. + +The GCC instruction scheduler uses a @dfn{pipeline hazard recognizer} to +figure out the possibility of the instruction issue by the processor +on a given simulated processor cycle. The pipeline hazard recognizer is +automatically generated from the processor pipeline description. The +pipeline hazard recognizer generated from the machine description +is based on a deterministic finite state automaton (@acronym{DFA}): +the instruction issue is possible if there is a transition from one +automaton state to another one. This algorithm is very fast, and +furthermore, its speed is not dependent on processor +complexity@footnote{However, the size of the automaton depends on + processor complexity. To limit this effect, machine descriptions + can split orthogonal parts of the machine description among several + automata: but then, since each of these must be stepped independently, + this does cause a small decrease in the algorithm's performance.}. + +@cindex automaton based pipeline description +The rest of this section describes the directives that constitute +an automaton-based processor pipeline description. The order of +these constructions within the machine description file is not +important. + +@findex define_automaton +@cindex pipeline hazard recognizer +The following optional construction describes names of automata +generated and used for the pipeline hazards recognition. Sometimes +the generated finite state automaton used by the pipeline hazard +recognizer is large. If we use more than one automaton and bind functional +units to the automata, the total size of the automata is usually +less than the size of the single automaton. If there is no one such +construction, only one finite state automaton is generated. + +@smallexample +(define_automaton @var{automata-names}) +@end smallexample + +@var{automata-names} is a string giving names of the automata. The +names are separated by commas. All the automata should have unique names. +The automaton name is used in the constructions @code{define_cpu_unit} and +@code{define_query_cpu_unit}. + +@findex define_cpu_unit +@cindex processor functional units +Each processor functional unit used in the description of instruction +reservations should be described by the following construction. + +@smallexample +(define_cpu_unit @var{unit-names} [@var{automaton-name}]) +@end smallexample + +@var{unit-names} is a string giving the names of the functional units +separated by commas. Don't use name @samp{nothing}, it is reserved +for other goals. + +@var{automaton-name} is a string giving the name of the automaton with +which the unit is bound. The automaton should be described in +construction @code{define_automaton}. You should give +@dfn{automaton-name}, if there is a defined automaton. + +The assignment of units to automata are constrained by the uses of the +units in insn reservations. The most important constraint is: if a +unit reservation is present on a particular cycle of an alternative +for an insn reservation, then some unit from the same automaton must +be present on the same cycle for the other alternatives of the insn +reservation. The rest of the constraints are mentioned in the +description of the subsequent constructions. + +@findex define_query_cpu_unit +@cindex querying function unit reservations +The following construction describes CPU functional units analogously +to @code{define_cpu_unit}. The reservation of such units can be +queried for an automaton state. The instruction scheduler never +queries reservation of functional units for given automaton state. So +as a rule, you don't need this construction. This construction could +be used for future code generation goals (e.g.@: to generate +@acronym{VLIW} insn templates). + +@smallexample +(define_query_cpu_unit @var{unit-names} [@var{automaton-name}]) +@end smallexample + +@var{unit-names} is a string giving names of the functional units +separated by commas. + +@var{automaton-name} is a string giving the name of the automaton with +which the unit is bound. + +@findex define_insn_reservation +@cindex instruction latency time +@cindex regular expressions +@cindex data bypass +The following construction is the major one to describe pipeline +characteristics of an instruction. + +@smallexample +(define_insn_reservation @var{insn-name} @var{default_latency} + @var{condition} @var{regexp}) +@end smallexample + +@var{default_latency} is a number giving latency time of the +instruction. There is an important difference between the old +description and the automaton based pipeline description. The latency +time is used for all dependencies when we use the old description. In +the automaton based pipeline description, the given latency time is only +used for true dependencies. The cost of anti-dependencies is always +zero and the cost of output dependencies is the difference between +latency times of the producing and consuming insns (if the difference +is negative, the cost is considered to be zero). You can always +change the default costs for any description by using the target hook +@code{TARGET_SCHED_ADJUST_COST} (@pxref{Scheduling}). + +@var{insn-name} is a string giving the internal name of the insn. The +internal names are used in constructions @code{define_bypass} and in +the automaton description file generated for debugging. The internal +name has nothing in common with the names in @code{define_insn}. It is a +good practice to use insn classes described in the processor manual. + +@var{condition} defines what RTL insns are described by this +construction. You should remember that you will be in trouble if +@var{condition} for two or more different +@code{define_insn_reservation} constructions is TRUE for an insn. In +this case what reservation will be used for the insn is not defined. +Such cases are not checked during generation of the pipeline hazards +recognizer because in general recognizing that two conditions may have +the same value is quite difficult (especially if the conditions +contain @code{symbol_ref}). It is also not checked during the +pipeline hazard recognizer work because it would slow down the +recognizer considerably. + +@var{regexp} is a string describing the reservation of the cpu's functional +units by the instruction. The reservations are described by a regular +expression according to the following syntax: + +@smallexample + regexp = regexp "," oneof + | oneof + + oneof = oneof "|" allof + | allof + + allof = allof "+" repeat + | repeat + + repeat = element "*" number + | element + + element = cpu_function_unit_name + | reservation_name + | result_name + | "nothing" + | "(" regexp ")" +@end smallexample + +@itemize @bullet +@item +@samp{,} is used for describing the start of the next cycle in +the reservation. + +@item +@samp{|} is used for describing a reservation described by the first +regular expression @strong{or} a reservation described by the second +regular expression @strong{or} etc. + +@item +@samp{+} is used for describing a reservation described by the first +regular expression @strong{and} a reservation described by the +second regular expression @strong{and} etc. + +@item +@samp{*} is used for convenience and simply means a sequence in which +the regular expression are repeated @var{number} times with cycle +advancing (see @samp{,}). + +@item +@samp{cpu_function_unit_name} denotes reservation of the named +functional unit. + +@item +@samp{reservation_name} --- see description of construction +@samp{define_reservation}. + +@item +@samp{nothing} denotes no unit reservations. +@end itemize + +@findex define_reservation +Sometimes unit reservations for different insns contain common parts. +In such case, you can simplify the pipeline description by describing +the common part by the following construction + +@smallexample +(define_reservation @var{reservation-name} @var{regexp}) +@end smallexample + +@var{reservation-name} is a string giving name of @var{regexp}. +Functional unit names and reservation names are in the same name +space. So the reservation names should be different from the +functional unit names and can not be the reserved name @samp{nothing}. + +@findex define_bypass +@cindex instruction latency time +@cindex data bypass +The following construction is used to describe exceptions in the +latency time for given instruction pair. This is so called bypasses. + +@smallexample +(define_bypass @var{number} @var{out_insn_names} @var{in_insn_names} + [@var{guard}]) +@end smallexample + +@var{number} defines when the result generated by the instructions +given in string @var{out_insn_names} will be ready for the +instructions given in string @var{in_insn_names}. The instructions in +the string are separated by commas. + +@var{guard} is an optional string giving the name of a C function which +defines an additional guard for the bypass. The function will get the +two insns as parameters. If the function returns zero the bypass will +be ignored for this case. The additional guard is necessary to +recognize complicated bypasses, e.g.@: when the consumer is only an address +of insn @samp{store} (not a stored value). + +@findex exclusion_set +@findex presence_set +@findex final_presence_set +@findex absence_set +@findex final_absence_set +@cindex VLIW +@cindex RISC +The following five constructions are usually used to describe +@acronym{VLIW} processors, or more precisely, to describe a placement +of small instructions into @acronym{VLIW} instruction slots. They +can be used for @acronym{RISC} processors, too. + +@smallexample +(exclusion_set @var{unit-names} @var{unit-names}) +(presence_set @var{unit-names} @var{patterns}) +(final_presence_set @var{unit-names} @var{patterns}) +(absence_set @var{unit-names} @var{patterns}) +(final_absence_set @var{unit-names} @var{patterns}) +@end smallexample + +@var{unit-names} is a string giving names of functional units +separated by commas. + +@var{patterns} is a string giving patterns of functional units +separated by comma. Currently pattern is one unit or units +separated by white-spaces. + +The first construction (@samp{exclusion_set}) means that each +functional unit in the first string can not be reserved simultaneously +with a unit whose name is in the second string and vice versa. For +example, the construction is useful for describing processors +(e.g.@: some SPARC processors) with a fully pipelined floating point +functional unit which can execute simultaneously only single floating +point insns or only double floating point insns. + +The second construction (@samp{presence_set}) means that each +functional unit in the first string can not be reserved unless at +least one of pattern of units whose names are in the second string is +reserved. This is an asymmetric relation. For example, it is useful +for description that @acronym{VLIW} @samp{slot1} is reserved after +@samp{slot0} reservation. We could describe it by the following +construction + +@smallexample +(presence_set "slot1" "slot0") +@end smallexample + +Or @samp{slot1} is reserved only after @samp{slot0} and unit @samp{b0} +reservation. In this case we could write + +@smallexample +(presence_set "slot1" "slot0 b0") +@end smallexample + +The third construction (@samp{final_presence_set}) is analogous to +@samp{presence_set}. The difference between them is when checking is +done. When an instruction is issued in given automaton state +reflecting all current and planned unit reservations, the automaton +state is changed. The first state is a source state, the second one +is a result state. Checking for @samp{presence_set} is done on the +source state reservation, checking for @samp{final_presence_set} is +done on the result reservation. This construction is useful to +describe a reservation which is actually two subsequent reservations. +For example, if we use + +@smallexample +(presence_set "slot1" "slot0") +@end smallexample + +the following insn will be never issued (because @samp{slot1} requires +@samp{slot0} which is absent in the source state). + +@smallexample +(define_reservation "insn_and_nop" "slot0 + slot1") +@end smallexample + +but it can be issued if we use analogous @samp{final_presence_set}. + +The forth construction (@samp{absence_set}) means that each functional +unit in the first string can be reserved only if each pattern of units +whose names are in the second string is not reserved. This is an +asymmetric relation (actually @samp{exclusion_set} is analogous to +this one but it is symmetric). For example it might be useful in a +@acronym{VLIW} description to say that @samp{slot0} cannot be reserved +after either @samp{slot1} or @samp{slot2} have been reserved. This +can be described as: + +@smallexample +(absence_set "slot0" "slot1, slot2") +@end smallexample + +Or @samp{slot2} can not be reserved if @samp{slot0} and unit @samp{b0} +are reserved or @samp{slot1} and unit @samp{b1} are reserved. In +this case we could write + +@smallexample +(absence_set "slot2" "slot0 b0, slot1 b1") +@end smallexample + +All functional units mentioned in a set should belong to the same +automaton. + +The last construction (@samp{final_absence_set}) is analogous to +@samp{absence_set} but checking is done on the result (state) +reservation. See comments for @samp{final_presence_set}. + +@findex automata_option +@cindex deterministic finite state automaton +@cindex nondeterministic finite state automaton +@cindex finite state automaton minimization +You can control the generator of the pipeline hazard recognizer with +the following construction. + +@smallexample +(automata_option @var{options}) +@end smallexample + +@var{options} is a string giving options which affect the generated +code. Currently there are the following options: + +@itemize @bullet +@item +@dfn{no-minimization} makes no minimization of the automaton. This is +only worth to do when we are debugging the description and need to +look more accurately at reservations of states. + +@item +@dfn{time} means printing additional time statistics about +generation of automata. + +@item +@dfn{v} means a generation of the file describing the result automata. +The file has suffix @samp{.dfa} and can be used for the description +verification and debugging. + +@item +@dfn{w} means a generation of warning instead of error for +non-critical errors. + +@item +@dfn{ndfa} makes nondeterministic finite state automata. This affects +the treatment of operator @samp{|} in the regular expressions. The +usual treatment of the operator is to try the first alternative and, +if the reservation is not possible, the second alternative. The +nondeterministic treatment means trying all alternatives, some of them +may be rejected by reservations in the subsequent insns. + +@item +@dfn{progress} means output of a progress bar showing how many states +were generated so far for automaton being processed. This is useful +during debugging a @acronym{DFA} description. If you see too many +generated states, you could interrupt the generator of the pipeline +hazard recognizer and try to figure out a reason for generation of the +huge automaton. +@end itemize + +As an example, consider a superscalar @acronym{RISC} machine which can +issue three insns (two integer insns and one floating point insn) on +the cycle but can finish only two insns. To describe this, we define +the following functional units. + +@smallexample +(define_cpu_unit "i0_pipeline, i1_pipeline, f_pipeline") +(define_cpu_unit "port0, port1") +@end smallexample + +All simple integer insns can be executed in any integer pipeline and +their result is ready in two cycles. The simple integer insns are +issued into the first pipeline unless it is reserved, otherwise they +are issued into the second pipeline. Integer division and +multiplication insns can be executed only in the second integer +pipeline and their results are ready correspondingly in 8 and 4 +cycles. The integer division is not pipelined, i.e.@: the subsequent +integer division insn can not be issued until the current division +insn finished. Floating point insns are fully pipelined and their +results are ready in 3 cycles. Where the result of a floating point +insn is used by an integer insn, an additional delay of one cycle is +incurred. To describe all of this we could specify + +@smallexample +(define_cpu_unit "div") + +(define_insn_reservation "simple" 2 (eq_attr "type" "int") + "(i0_pipeline | i1_pipeline), (port0 | port1)") + +(define_insn_reservation "mult" 4 (eq_attr "type" "mult") + "i1_pipeline, nothing*2, (port0 | port1)") + +(define_insn_reservation "div" 8 (eq_attr "type" "div") + "i1_pipeline, div*7, div + (port0 | port1)") + +(define_insn_reservation "float" 3 (eq_attr "type" "float") + "f_pipeline, nothing, (port0 | port1)) + +(define_bypass 4 "float" "simple,mult,div") +@end smallexample + +To simplify the description we could describe the following reservation + +@smallexample +(define_reservation "finish" "port0|port1") +@end smallexample + +and use it in all @code{define_insn_reservation} as in the following +construction + +@smallexample +(define_insn_reservation "simple" 2 (eq_attr "type" "int") + "(i0_pipeline | i1_pipeline), finish") +@end smallexample + + +@end ifset +@ifset INTERNALS +@node Conditional Execution +@section Conditional Execution +@cindex conditional execution +@cindex predication + +A number of architectures provide for some form of conditional +execution, or predication. The hallmark of this feature is the +ability to nullify most of the instructions in the instruction set. +When the instruction set is large and not entirely symmetric, it +can be quite tedious to describe these forms directly in the +@file{.md} file. An alternative is the @code{define_cond_exec} template. + +@findex define_cond_exec +@smallexample +(define_cond_exec + [@var{predicate-pattern}] + "@var{condition}" + "@var{output-template}") +@end smallexample + +@var{predicate-pattern} is the condition that must be true for the +insn to be executed at runtime and should match a relational operator. +One can use @code{match_operator} to match several relational operators +at once. Any @code{match_operand} operands must have no more than one +alternative. + +@var{condition} is a C expression that must be true for the generated +pattern to match. + +@findex current_insn_predicate +@var{output-template} is a string similar to the @code{define_insn} +output template (@pxref{Output Template}), except that the @samp{*} +and @samp{@@} special cases do not apply. This is only useful if the +assembly text for the predicate is a simple prefix to the main insn. +In order to handle the general case, there is a global variable +@code{current_insn_predicate} that will contain the entire predicate +if the current insn is predicated, and will otherwise be @code{NULL}. + +When @code{define_cond_exec} is used, an implicit reference to +the @code{predicable} instruction attribute is made. +@xref{Insn Attributes}. This attribute must be boolean (i.e.@: have +exactly two elements in its @var{list-of-values}). Further, it must +not be used with complex expressions. That is, the default and all +uses in the insns must be a simple constant, not dependent on the +alternative or anything else. + +For each @code{define_insn} for which the @code{predicable} +attribute is true, a new @code{define_insn} pattern will be +generated that matches a predicated version of the instruction. +For example, + +@smallexample +(define_insn "addsi" + [(set (match_operand:SI 0 "register_operand" "r") + (plus:SI (match_operand:SI 1 "register_operand" "r") + (match_operand:SI 2 "register_operand" "r")))] + "@var{test1}" + "add %2,%1,%0") + +(define_cond_exec + [(ne (match_operand:CC 0 "register_operand" "c") + (const_int 0))] + "@var{test2}" + "(%0)") +@end smallexample + +@noindent +generates a new pattern + +@smallexample +(define_insn "" + [(cond_exec + (ne (match_operand:CC 3 "register_operand" "c") (const_int 0)) + (set (match_operand:SI 0 "register_operand" "r") + (plus:SI (match_operand:SI 1 "register_operand" "r") + (match_operand:SI 2 "register_operand" "r"))))] + "(@var{test2}) && (@var{test1})" + "(%3) add %2,%1,%0") +@end smallexample + +@end ifset +@ifset INTERNALS +@node Constant Definitions +@section Constant Definitions +@cindex constant definitions +@findex define_constants + +Using literal constants inside instruction patterns reduces legibility and +can be a maintenance problem. + +To overcome this problem, you may use the @code{define_constants} +expression. It contains a vector of name-value pairs. From that +point on, wherever any of the names appears in the MD file, it is as +if the corresponding value had been written instead. You may use +@code{define_constants} multiple times; each appearance adds more +constants to the table. It is an error to redefine a constant with +a different value. + +To come back to the a29k load multiple example, instead of + +@smallexample +(define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI 179)) + (clobber (reg:SI 179))])] + "" + "loadm 0,0,%1,%2") +@end smallexample + +You could write: + +@smallexample +(define_constants [ + (R_BP 177) + (R_FC 178) + (R_CR 179) + (R_Q 180) +]) + +(define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI R_CR)) + (clobber (reg:SI R_CR))])] + "" + "loadm 0,0,%1,%2") +@end smallexample + +The constants that are defined with a define_constant are also output +in the insn-codes.h header file as #defines. +@end ifset +@ifset INTERNALS +@node Macros +@section Macros +@cindex macros in @file{.md} files + +Ports often need to define similar patterns for more than one machine +mode or for more than one rtx code. GCC provides some simple macro +facilities to make this process easier. + +@menu +* Mode Macros:: Generating variations of patterns for different modes. +* Code Macros:: Doing the same for codes. +@end menu + +@node Mode Macros +@subsection Mode Macros +@cindex mode macros in @file{.md} files + +Ports often need to define similar patterns for two or more different modes. +For example: + +@itemize @bullet +@item +If a processor has hardware support for both single and double +floating-point arithmetic, the @code{SFmode} patterns tend to be +very similar to the @code{DFmode} ones. + +@item +If a port uses @code{SImode} pointers in one configuration and +@code{DImode} pointers in another, it will usually have very similar +@code{SImode} and @code{DImode} patterns for manipulating pointers. +@end itemize + +Mode macros allow several patterns to be instantiated from one +@file{.md} file template. They can be used with any type of +rtx-based construct, such as a @code{define_insn}, +@code{define_split}, or @code{define_peephole2}. + +@menu +* Defining Mode Macros:: Defining a new mode macro. +* Substitutions:: Combining mode macros with substitutions +* Examples:: Examples +@end menu + +@node Defining Mode Macros +@subsubsection Defining Mode Macros +@findex define_mode_macro + +The syntax for defining a mode macro is: + +@smallexample +(define_mode_macro @var{name} [(@var{mode1} "@var{cond1}") ... (@var{moden} "@var{condn}")]) +@end smallexample + +This allows subsequent @file{.md} file constructs to use the mode suffix +@code{:@var{name}}. Every construct that does so will be expanded +@var{n} times, once with every use of @code{:@var{name}} replaced by +@code{:@var{mode1}}, once with every use replaced by @code{:@var{mode2}}, +and so on. In the expansion for a particular @var{modei}, every +C condition will also require that @var{condi} be true. + +For example: + +@smallexample +(define_mode_macro P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) +@end smallexample + +defines a new mode suffix @code{:P}. Every construct that uses +@code{:P} will be expanded twice, once with every @code{:P} replaced +by @code{:SI} and once with every @code{:P} replaced by @code{:DI}. +The @code{:SI} version will only apply if @code{Pmode == SImode} and +the @code{:DI} version will only apply if @code{Pmode == DImode}. + +As with other @file{.md} conditions, an empty string is treated +as ``always true''. @code{(@var{mode} "")} can also be abbreviated +to @code{@var{mode}}. For example: + +@smallexample +(define_mode_macro GPR [SI (DI "TARGET_64BIT")]) +@end smallexample + +means that the @code{:DI} expansion only applies if @code{TARGET_64BIT} +but that the @code{:SI} expansion has no such constraint. + +Macros are applied in the order they are defined. This can be +significant if two macros are used in a construct that requires +substitutions. @xref{Substitutions}. + +@node Substitutions +@subsubsection Substitution in Mode Macros +@findex define_mode_attr + +If an @file{.md} file construct uses mode macros, each version of the +construct will often need slightly different strings or modes. For +example: + +@itemize @bullet +@item +When a @code{define_expand} defines several @code{add@var{m}3} patterns +(@pxref{Standard Names}), each expander will need to use the +appropriate mode name for @var{m}. + +@item +When a @code{define_insn} defines several instruction patterns, +each instruction will often use a different assembler mnemonic. + +@item +When a @code{define_insn} requires operands with different modes, +using a macro for one of the operand modes usually requires a specific +mode for the other operand(s). +@end itemize + +GCC supports such variations through a system of ``mode attributes''. +There are two standard attributes: @code{mode}, which is the name of +the mode in lower case, and @code{MODE}, which is the same thing in +upper case. You can define other attributes using: + +@smallexample +(define_mode_attr @var{name} [(@var{mode1} "@var{value1}") ... (@var{moden} "@var{valuen}")]) +@end smallexample + +where @var{name} is the name of the attribute and @var{valuei} +is the value associated with @var{modei}. + +When GCC replaces some @var{:macro} with @var{:mode}, it will scan +each string and mode in the pattern for sequences of the form +@code{<@var{macro}:@var{attr}>}, where @var{attr} is the name of a +mode attribute. If the attribute is defined for @var{mode}, the whole +@code{<...>} sequence will be replaced by the appropriate attribute +value. + +For example, suppose an @file{.md} file has: + +@smallexample +(define_mode_macro P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) +(define_mode_attr load [(SI "lw") (DI "ld")]) +@end smallexample + +If one of the patterns that uses @code{:P} contains the string +@code{"<P:load>\t%0,%1"}, the @code{SI} version of that pattern +will use @code{"lw\t%0,%1"} and the @code{DI} version will use +@code{"ld\t%0,%1"}. + +Here is an example of using an attribute for a mode: + +@smallexample +(define_mode_macro LONG [SI DI]) +(define_mode_attr SHORT [(SI "HI") (DI "SI")]) +(define_insn ... + (sign_extend:LONG (match_operand:<LONG:SHORT> ...)) ...) +@end smallexample + +The @code{@var{macro}:} prefix may be omitted, in which case the +substitution will be attempted for every macro expansion. + +@node Examples +@subsubsection Mode Macro Examples + +Here is an example from the MIPS port. It defines the following +modes and attributes (among others): + +@smallexample +(define_mode_macro GPR [SI (DI "TARGET_64BIT")]) +(define_mode_attr d [(SI "") (DI "d")]) +@end smallexample + +and uses the following template to define both @code{subsi3} +and @code{subdi3}: + +@smallexample +(define_insn "sub<mode>3" + [(set (match_operand:GPR 0 "register_operand" "=d") + (minus:GPR (match_operand:GPR 1 "register_operand" "d") + (match_operand:GPR 2 "register_operand" "d")))] + "" + "<d>subu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "<MODE>")]) +@end smallexample + +This is exactly equivalent to: + +@smallexample +(define_insn "subsi3" + [(set (match_operand:SI 0 "register_operand" "=d") + (minus:SI (match_operand:SI 1 "register_operand" "d") + (match_operand:SI 2 "register_operand" "d")))] + "" + "subu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "SI")]) + +(define_insn "subdi3" + [(set (match_operand:DI 0 "register_operand" "=d") + (minus:DI (match_operand:DI 1 "register_operand" "d") + (match_operand:DI 2 "register_operand" "d")))] + "" + "dsubu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "DI")]) +@end smallexample + +@node Code Macros +@subsection Code Macros +@cindex code macros in @file{.md} files +@findex define_code_macro +@findex define_code_attr + +Code macros operate in a similar way to mode macros. @xref{Mode Macros}. + +The construct: + +@smallexample +(define_code_macro @var{name} [(@var{code1} "@var{cond1}") ... (@var{coden} "@var{condn}")]) +@end smallexample + +defines a pseudo rtx code @var{name} that can be instantiated as +@var{codei} if condition @var{condi} is true. Each @var{codei} +must have the same rtx format. @xref{RTL Classes}. + +As with mode macros, each pattern that uses @var{name} will be +expanded @var{n} times, once with all uses of @var{name} replaced by +@var{code1}, once with all uses replaced by @var{code2}, and so on. +@xref{Defining Mode Macros}. + +It is possible to define attributes for codes as well as for modes. +There are two standard code attributes: @code{code}, the name of the +code in lower case, and @code{CODE}, the name of the code in upper case. +Other attributes are defined using: + +@smallexample +(define_code_attr @var{name} [(@var{code1} "@var{value1}") ... (@var{coden} "@var{valuen}")]) +@end smallexample + +Here's an example of code macros in action, taken from the MIPS port: + +@smallexample +(define_code_macro any_cond [unordered ordered unlt unge uneq ltgt unle ungt + eq ne gt ge lt le gtu geu ltu leu]) + +(define_expand "b<code>" + [(set (pc) + (if_then_else (any_cond:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" +@{ + gen_conditional_branch (operands, <CODE>); + DONE; +@}) +@end smallexample + +This is equivalent to: + +@smallexample +(define_expand "bunordered" + [(set (pc) + (if_then_else (unordered:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" +@{ + gen_conditional_branch (operands, UNORDERED); + DONE; +@}) + +(define_expand "bordered" + [(set (pc) + (if_then_else (ordered:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" +@{ + gen_conditional_branch (operands, ORDERED); + DONE; +@}) + +... +@end smallexample + +@end ifset diff --git a/gcc-4.2.1-5666.3/gcc/doc/objc.texi b/gcc-4.2.1-5666.3/gcc/doc/objc.texi new file mode 100644 index 000000000..c15c1acf8 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/objc.texi @@ -0,0 +1,478 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Objective-C +@comment node-name, next, previous, up + +@chapter GNU Objective-C runtime features + +This document is meant to describe some of the GNU Objective-C runtime +features. It is not intended to teach you Objective-C, there are several +resources on the Internet that present the language. Questions and +comments about this document to Ovidiu Predescu +@email{ovidiu@@cup.hp.com}. + +@menu +* Executing code before main:: +* Type encoding:: +* Garbage Collection:: +* Constant string objects:: +* compatibility_alias:: +@end menu + +@node Executing code before main, Type encoding, Objective-C, Objective-C +@section @code{+load}: Executing code before main + +The GNU Objective-C runtime provides a way that allows you to execute +code before the execution of the program enters the @code{main} +function. The code is executed on a per-class and a per-category basis, +through a special class method @code{+load}. + +This facility is very useful if you want to initialize global variables +which can be accessed by the program directly, without sending a message +to the class first. The usual way to initialize global variables, in the +@code{+initialize} method, might not be useful because +@code{+initialize} is only called when the first message is sent to a +class object, which in some cases could be too late. + +Suppose for example you have a @code{FileStream} class that declares +@code{Stdin}, @code{Stdout} and @code{Stderr} as global variables, like +below: + +@smallexample + +FileStream *Stdin = nil; +FileStream *Stdout = nil; +FileStream *Stderr = nil; + +@@implementation FileStream + ++ (void)initialize +@{ + Stdin = [[FileStream new] initWithFd:0]; + Stdout = [[FileStream new] initWithFd:1]; + Stderr = [[FileStream new] initWithFd:2]; +@} + +/* @r{Other methods here} */ +@@end + +@end smallexample + +In this example, the initialization of @code{Stdin}, @code{Stdout} and +@code{Stderr} in @code{+initialize} occurs too late. The programmer can +send a message to one of these objects before the variables are actually +initialized, thus sending messages to the @code{nil} object. The +@code{+initialize} method which actually initializes the global +variables is not invoked until the first message is sent to the class +object. The solution would require these variables to be initialized +just before entering @code{main}. + +The correct solution of the above problem is to use the @code{+load} +method instead of @code{+initialize}: + +@smallexample + +@@implementation FileStream + ++ (void)load +@{ + Stdin = [[FileStream new] initWithFd:0]; + Stdout = [[FileStream new] initWithFd:1]; + Stderr = [[FileStream new] initWithFd:2]; +@} + +/* @r{Other methods here} */ +@@end + +@end smallexample + +The @code{+load} is a method that is not overridden by categories. If a +class and a category of it both implement @code{+load}, both methods are +invoked. This allows some additional initializations to be performed in +a category. + +This mechanism is not intended to be a replacement for @code{+initialize}. +You should be aware of its limitations when you decide to use it +instead of @code{+initialize}. + +@menu +* What you can and what you cannot do in +load:: +@end menu + + +@node What you can and what you cannot do in +load, , Executing code before main, Executing code before main +@subsection What you can and what you cannot do in @code{+load} + +The @code{+load} implementation in the GNU runtime guarantees you the following +things: + +@itemize @bullet + +@item +you can write whatever C code you like; + +@item +you can send messages to Objective-C constant strings (@code{@@"this is a +constant string"}); + +@item +you can allocate and send messages to objects whose class is implemented +in the same file; + +@item +the @code{+load} implementation of all super classes of a class are executed before the @code{+load} of that class is executed; + +@item +the @code{+load} implementation of a class is executed before the +@code{+load} implementation of any category. + +@end itemize + +In particular, the following things, even if they can work in a +particular case, are not guaranteed: + +@itemize @bullet + +@item +allocation of or sending messages to arbitrary objects; + +@item +allocation of or sending messages to objects whose classes have a +category implemented in the same file; + +@end itemize + +You should make no assumptions about receiving @code{+load} in sibling +classes when you write @code{+load} of a class. The order in which +sibling classes receive @code{+load} is not guaranteed. + +The order in which @code{+load} and @code{+initialize} are called could +be problematic if this matters. If you don't allocate objects inside +@code{+load}, it is guaranteed that @code{+load} is called before +@code{+initialize}. If you create an object inside @code{+load} the +@code{+initialize} method of object's class is invoked even if +@code{+load} was not invoked. Note if you explicitly call @code{+load} +on a class, @code{+initialize} will be called first. To avoid possible +problems try to implement only one of these methods. + +The @code{+load} method is also invoked when a bundle is dynamically +loaded into your running program. This happens automatically without any +intervening operation from you. When you write bundles and you need to +write @code{+load} you can safely create and send messages to objects whose +classes already exist in the running program. The same restrictions as +above apply to classes defined in bundle. + + + +@node Type encoding, Garbage Collection, Executing code before main, Objective-C +@section Type encoding + +The Objective-C compiler generates type encodings for all the +types. These type encodings are used at runtime to find out information +about selectors and methods and about objects and classes. + +The types are encoded in the following way: + +@c @sp 1 + +@multitable @columnfractions .25 .75 +@item @code{_Bool} +@tab @code{B} +@item @code{char} +@tab @code{c} +@item @code{unsigned char} +@tab @code{C} +@item @code{short} +@tab @code{s} +@item @code{unsigned short} +@tab @code{S} +@item @code{int} +@tab @code{i} +@item @code{unsigned int} +@tab @code{I} +@item @code{long} +@tab @code{l} +@item @code{unsigned long} +@tab @code{L} +@item @code{long long} +@tab @code{q} +@item @code{unsigned long long} +@tab @code{Q} +@item @code{float} +@tab @code{f} +@item @code{double} +@tab @code{d} +@item @code{void} +@tab @code{v} +@item @code{id} +@tab @code{@@} +@item @code{Class} +@tab @code{#} +@item @code{SEL} +@tab @code{:} +@item @code{char*} +@tab @code{*} +@item unknown type +@tab @code{?} +@item Complex types +@tab @code{j} followed by the inner type. For example @code{_Complex double} is encoded as "jd". +@item bit-fields +@tab @code{b} followed by the starting position of the bit-field, the type of the bit-field and the size of the bit-field (the bit-fields encoding was changed from the NeXT's compiler encoding, see below) +@end multitable + +@c @sp 1 + +The encoding of bit-fields has changed to allow bit-fields to be properly +handled by the runtime functions that compute sizes and alignments of +types that contain bit-fields. The previous encoding contained only the +size of the bit-field. Using only this information it is not possible to +reliably compute the size occupied by the bit-field. This is very +important in the presence of the Boehm's garbage collector because the +objects are allocated using the typed memory facility available in this +collector. The typed memory allocation requires information about where +the pointers are located inside the object. + +The position in the bit-field is the position, counting in bits, of the +bit closest to the beginning of the structure. + +The non-atomic types are encoded as follows: + +@c @sp 1 + +@multitable @columnfractions .2 .8 +@item pointers +@tab @samp{^} followed by the pointed type. +@item arrays +@tab @samp{[} followed by the number of elements in the array followed by the type of the elements followed by @samp{]} +@item structures +@tab @samp{@{} followed by the name of the structure (or @samp{?} if the structure is unnamed), the @samp{=} sign, the type of the members and by @samp{@}} +@item unions +@tab @samp{(} followed by the name of the structure (or @samp{?} if the union is unnamed), the @samp{=} sign, the type of the members followed by @samp{)} +@end multitable + +Here are some types and their encodings, as they are generated by the +compiler on an i386 machine: + +@sp 1 + +@multitable @columnfractions .25 .75 +@item Objective-C type +@tab Compiler encoding +@item +@smallexample +int a[10]; +@end smallexample +@tab @code{[10i]} +@item +@smallexample +struct @{ + int i; + float f[3]; + int a:3; + int b:2; + char c; +@} +@end smallexample +@tab @code{@{?=i[3f]b128i3b131i2c@}} +@end multitable + +@sp 1 + +In addition to the types the compiler also encodes the type +specifiers. The table below describes the encoding of the current +Objective-C type specifiers: + +@sp 1 + +@multitable @columnfractions .25 .75 +@item Specifier +@tab Encoding +@item @code{const} +@tab @code{r} +@item @code{in} +@tab @code{n} +@item @code{inout} +@tab @code{N} +@item @code{out} +@tab @code{o} +@item @code{bycopy} +@tab @code{O} +@item @code{oneway} +@tab @code{V} +@end multitable + +@sp 1 + +The type specifiers are encoded just before the type. Unlike types +however, the type specifiers are only encoded when they appear in method +argument types. + + +@node Garbage Collection, Constant string objects, Type encoding, Objective-C +@section Garbage Collection + +Support for a new memory management policy has been added by using a +powerful conservative garbage collector, known as the +Boehm-Demers-Weiser conservative garbage collector. It is available from +@w{@uref{http://www.hpl.hp.com/personal/Hans_Boehm/gc/}}. + +To enable the support for it you have to configure the compiler using an +additional argument, @w{@option{--enable-objc-gc}}. You need to have +garbage collector installed before building the compiler. This will +build an additional runtime library which has several enhancements to +support the garbage collector. The new library has a new name, +@file{libobjc_gc.a} to not conflict with the non-garbage-collected +library. + +When the garbage collector is used, the objects are allocated using the +so-called typed memory allocation mechanism available in the +Boehm-Demers-Weiser collector. This mode requires precise information on +where pointers are located inside objects. This information is computed +once per class, immediately after the class has been initialized. + +There is a new runtime function @code{class_ivar_set_gcinvisible()} +which can be used to declare a so-called @dfn{weak pointer} +reference. Such a pointer is basically hidden for the garbage collector; +this can be useful in certain situations, especially when you want to +keep track of the allocated objects, yet allow them to be +collected. This kind of pointers can only be members of objects, you +cannot declare a global pointer as a weak reference. Every type which is +a pointer type can be declared a weak pointer, including @code{id}, +@code{Class} and @code{SEL}. + +Here is an example of how to use this feature. Suppose you want to +implement a class whose instances hold a weak pointer reference; the +following class does this: + +@smallexample + +@@interface WeakPointer : Object +@{ + const void* weakPointer; +@} + +- initWithPointer:(const void*)p; +- (const void*)weakPointer; +@@end + + +@@implementation WeakPointer + ++ (void)initialize +@{ + class_ivar_set_gcinvisible (self, "weakPointer", YES); +@} + +- initWithPointer:(const void*)p +@{ + weakPointer = p; + return self; +@} + +- (const void*)weakPointer +@{ + return weakPointer; +@} + +@@end + +@end smallexample + +Weak pointers are supported through a new type character specifier +represented by the @samp{!} character. The +@code{class_ivar_set_gcinvisible()} function adds or removes this +specifier to the string type description of the instance variable named +as argument. + +@c ========================================================================= +@node Constant string objects +@section Constant string objects + +GNU Objective-C provides constant string objects that are generated +directly by the compiler. You declare a constant string object by +prefixing a C constant string with the character @samp{@@}: + +@smallexample + id myString = @@"this is a constant string object"; +@end smallexample + +The constant string objects are by default instances of the +@code{NXConstantString} class which is provided by the GNU Objective-C +runtime. To get the definition of this class you must include the +@file{objc/NXConstStr.h} header file. + +User defined libraries may want to implement their own constant string +class. To be able to support them, the GNU Objective-C compiler provides +a new command line options @option{-fconstant-string-class=@var{class-name}}. +The provided class should adhere to a strict structure, the same +as @code{NXConstantString}'s structure: + +@smallexample + +@@interface MyConstantStringClass +@{ + Class isa; + char *c_string; + unsigned int len; +@} +@@end + +@end smallexample + +@code{NXConstantString} inherits from @code{Object}; user class +libraries may choose to inherit the customized constant string class +from a different class than @code{Object}. There is no requirement in +the methods the constant string class has to implement, but the final +ivar layout of the class must be the compatible with the given +structure. + +When the compiler creates the statically allocated constant string +object, the @code{c_string} field will be filled by the compiler with +the string; the @code{length} field will be filled by the compiler with +the string length; the @code{isa} pointer will be filled with +@code{NULL} by the compiler, and it will later be fixed up automatically +at runtime by the GNU Objective-C runtime library to point to the class +which was set by the @option{-fconstant-string-class} option when the +object file is loaded (if you wonder how it works behind the scenes, the +name of the class to use, and the list of static objects to fixup, are +stored by the compiler in the object file in a place where the GNU +runtime library will find them at runtime). + +As a result, when a file is compiled with the +@option{-fconstant-string-class} option, all the constant string objects +will be instances of the class specified as argument to this option. It +is possible to have multiple compilation units referring to different +constant string classes, neither the compiler nor the linker impose any +restrictions in doing this. + +@c ========================================================================= +@node compatibility_alias +@section compatibility_alias + +This is a feature of the Objective-C compiler rather than of the +runtime, anyway since it is documented nowhere and its existence was +forgotten, we are documenting it here. + +The keyword @code{@@compatibility_alias} allows you to define a class name +as equivalent to another class name. For example: + +@smallexample +@@compatibility_alias WOApplication GSWApplication; +@end smallexample + +tells the compiler that each time it encounters @code{WOApplication} as +a class name, it should replace it with @code{GSWApplication} (that is, +@code{WOApplication} is just an alias for @code{GSWApplication}). + +There are some constraints on how this can be used--- + +@itemize @bullet + +@item @code{WOApplication} (the alias) must not be an existing class; + +@item @code{GSWApplication} (the real class) must be an existing class. + +@end itemize diff --git a/gcc-4.2.1-5666.3/gcc/doc/options.texi b/gcc-4.2.1-5666.3/gcc/doc/options.texi new file mode 100644 index 000000000..05fa05b53 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/options.texi @@ -0,0 +1,224 @@ +@c Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Options +@chapter Option specification files +@cindex option specification files +@cindex @samp{opts.sh} + +Most GCC command-line options are described by special option +definition files, the names of which conventionally end in +@code{.opt}. This chapter describes the format of these files. + +@menu +* Option file format:: The general layout of the files +* Option properties:: Supported option properties +@end menu + +@node Option file format +@section Option file format + +Option files are a simple list of records in which each field occupies +its own line and in which the records themselves are separated by +blank lines. Comments may appear on their own line anywhere within +the file and are preceded by semicolons. Whitespace is allowed before +the semicolon. + +The files can contain the following types of record: + +@itemize @bullet +@item +A language definition record. These records have two fields: the +string @samp{Language} and the name of the language. Once a language +has been declared in this way, it can be used as an option property. +@xref{Option properties}. + +@item +An option definition record. These records have the following fields: + +@enumerate +@item +the name of the option, with the leading ``-'' removed +@item +a space-separated list of option properties (@pxref{Option properties}) +@item +the help text to use for @option{--help} (omitted if the second field +contains the @code{Undocumented} property). +@end enumerate + +By default, all options beginning with ``f'', ``W'' or ``m'' are +implicitly assumed to take a ``no-'' form. This form should not be +listed separately. If an option beginning with one of these letters +does not have a ``no-'' form, you can use the @code{RejectNegative} +property to reject it. + +The help text is automatically line-wrapped before being displayed. +Normally the name of the option is printed on the left-hand side of +the output and the help text is printed on the right. However, if the +help text contains a tab character, the text to the left of the tab is +used instead of the option's name and the text to the right of the +tab forms the help text. This allows you to elaborate on what type +of argument the option takes. + +@item +A target mask record. These records have one field of the form +@samp{Mask(@var{x})}. The options-processing script will automatically +allocate a bit in @code{target_flags} (@pxref{Run-time Target}) for +each mask name @var{x} and set the macro @code{MASK_@var{x}} to the +appropriate bitmask. It will also declare a @code{TARGET_@var{x}} +macro that has the value 1 when bit @code{MASK_@var{x}} is set and +0 otherwise. + +They are primarily intended to declare target masks that are not +associated with user options, either because these masks represent +internal switches or because the options are not available on all +configurations and yet the masks always need to be defined. +@end itemize + +@node Option properties +@section Option properties + +The second field of an option record can specify the following properties: + +@table @code +@item Common +The option is available for all languages and targets. + +@item Target +The option is available for all languages but is target-specific. + +@item @var{language} +The option is available when compiling for the given language. + +It is possible to specify several different languages for the same +option. Each @var{language} must have been declared by an earlier +@code{Language} record. @xref{Option file format}. + +@item RejectNegative +The option does not have a ``no-'' form. All options beginning with +``f'', ``W'' or ``m'' are assumed to have a ``no-'' form unless this +property is used. + +@item Negative(@var{othername}) +The option will turn off another option @var{othername}, which is the +the option name with the leading ``-'' removed. This chain action will +propagate through the @code{Negative} property of the option to be +turned off. + +@item Joined +@itemx Separate +The option takes a mandatory argument. @code{Joined} indicates +that the option and argument can be included in the same @code{argv} +entry (as with @code{-mflush-func=@var{name}}, for example). +@code{Separate} indicates that the option and argument can be +separate @code{argv} entries (as with @code{-o}). An option is +allowed to have both of these properties. + +@item JoinedOrMissing +The option takes an optional argument. If the argument is given, +it will be part of the same @code{argv} entry as the option itself. + +This property cannot be used alongside @code{Joined} or @code{Separate}. + +@item UInteger +The option's argument is a non-negative integer. The option parser +will check and convert the argument before passing it to the relevant +option handler. + +@item Var(@var{var}) +The state of this option should be stored in variable @var{var}. +The way that the state is stored depends on the type of option: + +@itemize @bullet +@item +If the option uses the @code{Mask} or @code{InverseMask} properties, +@var{var} is the integer variable that contains the mask. + +@item +If the option is a normal on/off switch, @var{var} is an integer +variable that is nonzero when the option is enabled. The options +parser will set the variable to 1 when the positive form of the +option is used and 0 when the ``no-'' form is used. + +@item +If the option takes an argument and has the @code{UInteger} property, +@var{var} is an integer variable that stores the value of the argument. + +@item +Otherwise, if the option takes an argument, @var{var} is a pointer to +the argument string. The pointer will be null if the argument is optional +and wasn't given. +@end itemize + +The option-processing script will usually declare @var{var} in +@file{options.c} and leave it to be zero-initialized at start-up time. +You can modify this behavior using @code{VarExists} and @code{Init}. + +@item Var(@var{var}, @var{set}) +The option controls an integer variable @var{var} and is active when +@var{var} equals @var{set}. The option parser will set @var{var} to +@var{set} when the positive form of the option is used and @code{!@var{set}} +when the ``no-'' form is used. + +@var{var} is declared in the same way as for the single-argument form +described above. + +@item VarExists +The variable specified by the @code{Var} property already exists. +No definition should be added to @file{options.c} in response to +this option record. + +You should use this property only if the variable is declared outside +@file{options.c}. + +@item Init(@var{value}) +The variable specified by the @code{Var} property should be statically +initialized to @var{value}. + +@item Mask(@var{name}) +The option is associated with a bit in the @code{target_flags} +variable (@pxref{Run-time Target}) and is active when that bit is set. +You may also specify @code{Var} to select a variable other than +@code{target_flags}. + +The options-processing script will automatically allocate a unique bit +for the option. If the option is attached to @samp{target_flags}, +the script will set the macro @code{MASK_@var{name}} to the appropriate +bitmask. It will also declare a @code{TARGET_@var{name}} macro that has +the value 1 when the option is active and 0 otherwise. If you use @code{Var} +to attach the option to a different variable, the associated macros are +called @code{OPTION_MASK_@var{name}} and @code{OPTION_@var{name}} respectively. + +You can disable automatic bit allocation using @code{MaskExists}. + +@item InverseMask(@var{othername}) +@itemx InverseMask(@var{othername}, @var{thisname}) +The option is the inverse of another option that has the +@code{Mask(@var{othername})} property. If @var{thisname} is given, +the options-processing script will declare a @code{TARGET_@var{thisname}} +macro that is 1 when the option is active and 0 otherwise. + +@item MaskExists +The mask specified by the @code{Mask} property already exists. +No @code{MASK} or @code{TARGET} definitions should be added to +@file{options.h} in response to this option record. + +The main purpose of this property is to support synonymous options. +The first option should use @samp{Mask(@var{name})} and the others +should use @samp{Mask(@var{name}) MaskExists}. + +@item Report +The state of the option should be printed by @option{-fverbose-asm}. + +@item Undocumented +The option is deliberately missing documentation and should not +be included in the @option{--help} output. + +@item Condition(@var{cond}) +The option should only be accepted if preprocessor condition +@var{cond} is true. Note that any C declarations associated with the +option will be present even if @var{cond} is false; @var{cond} simply +controls whether the option is accepted and whether it is printed in +the @option{--help} output. +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/passes.texi b/gcc-4.2.1-5666.3/gcc/doc/passes.texi new file mode 100644 index 000000000..243c646be --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/passes.texi @@ -0,0 +1,901 @@ +@c markers: CROSSREF BUG TODO + +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, +@c 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Passes +@chapter Passes and Files of the Compiler +@cindex passes and files of the compiler +@cindex files and passes of the compiler +@cindex compiler passes and files + +This chapter is dedicated to giving an overview of the optimization and +code generation passes of the compiler. In the process, it describes +some of the language front end interface, though this description is no +where near complete. + +@menu +* Parsing pass:: The language front end turns text into bits. +* Gimplification pass:: The bits are turned into something we can optimize. +* Pass manager:: Sequencing the optimization passes. +* Tree-SSA passes:: Optimizations on a high-level representation. +* RTL passes:: Optimizations on a low-level representation. +@end menu + +@node Parsing pass +@section Parsing pass +@cindex GENERIC +@findex lang_hooks.parse_file +The language front end is invoked only once, via +@code{lang_hooks.parse_file}, to parse the entire input. The language +front end may use any intermediate language representation deemed +appropriate. The C front end uses GENERIC trees (CROSSREF), plus +a double handful of language specific tree codes defined in +@file{c-common.def}. The Fortran front end uses a completely different +private representation. + +@cindex GIMPLE +@cindex gimplification +@cindex gimplifier +@cindex language-independent intermediate representation +@cindex intermediate representation lowering +@cindex lowering, language-dependent intermediate representation +At some point the front end must translate the representation used in the +front end to a representation understood by the language-independent +portions of the compiler. Current practice takes one of two forms. +The C front end manually invokes the gimplifier (CROSSREF) on each function, +and uses the gimplifier callbacks to convert the language-specific tree +nodes directly to GIMPLE (CROSSREF) before passing the function off to +be compiled. +The Fortran front end converts from a private representation to GENERIC, +which is later lowered to GIMPLE when the function is compiled. Which +route to choose probably depends on how well GENERIC (plus extensions) +can be made to match up with the source language and necessary parsing +data structures. + +BUG: Gimplification must occur before nested function lowering, +and nested function lowering must be done by the front end before +passing the data off to cgraph. + +TODO: Cgraph should control nested function lowering. It would +only be invoked when it is certain that the outer-most function +is used. + +TODO: Cgraph needs a gimplify_function callback. It should be +invoked when (1) it is certain that the function is used, (2) +warning flags specified by the user require some amount of +compilation in order to honor, (3) the language indicates that +semantic analysis is not complete until gimplification occurs. +Hum@dots{} this sounds overly complicated. Perhaps we should just +have the front end gimplify always; in most cases it's only one +function call. + +The front end needs to pass all function definitions and top level +declarations off to the middle-end so that they can be compiled and +emitted to the object file. For a simple procedural language, it is +usually most convenient to do this as each top level declaration or +definition is seen. There is also a distinction to be made between +generating functional code and generating complete debug information. +The only thing that is absolutely required for functional code is that +function and data @emph{definitions} be passed to the middle-end. For +complete debug information, function, data and type declarations +should all be passed as well. + +@findex rest_of_decl_compilation +@findex rest_of_type_compilation +@findex cgraph_finalize_function +In any case, the front end needs each complete top-level function or +data declaration, and each data definition should be passed to +@code{rest_of_decl_compilation}. Each complete type definition should +be passed to @code{rest_of_type_compilation}. Each function definition +should be passed to @code{cgraph_finalize_function}. + +TODO: I know rest_of_compilation currently has all sorts of +rtl-generation semantics. I plan to move all code generation +bits (both tree and rtl) to compile_function. Should we hide +cgraph from the front ends and move back to rest_of_compilation +as the official interface? Possibly we should rename all three +interfaces such that the names match in some meaningful way and +that is more descriptive than "rest_of". + +The middle-end will, at its option, emit the function and data +definitions immediately or queue them for later processing. + +@node Gimplification pass +@section Gimplification pass + +@cindex gimplification +@cindex GIMPLE +@dfn{Gimplification} is a whimsical term for the process of converting +the intermediate representation of a function into the GIMPLE language +(CROSSREF). The term stuck, and so words like ``gimplification'', +``gimplify'', ``gimplifier'' and the like are sprinkled throughout this +section of code. + +@cindex GENERIC +While a front end may certainly choose to generate GIMPLE directly if +it chooses, this can be a moderately complex process unless the +intermediate language used by the front end is already fairly simple. +Usually it is easier to generate GENERIC trees plus extensions +and let the language-independent gimplifier do most of the work. + +@findex gimplify_function_tree +@findex gimplify_expr +@findex lang_hooks.gimplify_expr +The main entry point to this pass is @code{gimplify_function_tree} +located in @file{gimplify.c}. From here we process the entire +function gimplifying each statement in turn. The main workhorse +for this pass is @code{gimplify_expr}. Approximately everything +passes through here at least once, and it is from here that we +invoke the @code{lang_hooks.gimplify_expr} callback. + +The callback should examine the expression in question and return +@code{GS_UNHANDLED} if the expression is not a language specific +construct that requires attention. Otherwise it should alter the +expression in some way to such that forward progress is made toward +producing valid GIMPLE@. If the callback is certain that the +transformation is complete and the expression is valid GIMPLE, it +should return @code{GS_ALL_DONE}. Otherwise it should return +@code{GS_OK}, which will cause the expression to be processed again. +If the callback encounters an error during the transformation (because +the front end is relying on the gimplification process to finish +semantic checks), it should return @code{GS_ERROR}. + +@node Pass manager +@section Pass manager + +The pass manager is located in @file{passes.c}, @file{tree-optimize.c} +and @file{tree-pass.h}. +Its job is to run all of the individual passes in the correct order, +and take care of standard bookkeeping that applies to every pass. + +The theory of operation is that each pass defines a structure that +represents everything we need to know about that pass---when it +should be run, how it should be run, what intermediate language +form or on-the-side data structures it needs. We register the pass +to be run in some particular order, and the pass manager arranges +for everything to happen in the correct order. + +The actuality doesn't completely live up to the theory at present. +Command-line switches and @code{timevar_id_t} enumerations must still +be defined elsewhere. The pass manager validates constraints but does +not attempt to (re-)generate data structures or lower intermediate +language form based on the requirements of the next pass. Nevertheless, +what is present is useful, and a far sight better than nothing at all. + +TODO: describe the global variables set up by the pass manager, +and a brief description of how a new pass should use it. +I need to look at what info rtl passes use first... + +@node Tree-SSA passes +@section Tree-SSA passes + +The following briefly describes the tree optimization passes that are +run after gimplification and what source files they are located in. + +@itemize @bullet +@item Remove useless statements + +This pass is an extremely simple sweep across the gimple code in which +we identify obviously dead code and remove it. Here we do things like +simplify @code{if} statements with constant conditions, remove +exception handling constructs surrounding code that obviously cannot +throw, remove lexical bindings that contain no variables, and other +assorted simplistic cleanups. The idea is to get rid of the obvious +stuff quickly rather than wait until later when it's more work to get +rid of it. This pass is located in @file{tree-cfg.c} and described by +@code{pass_remove_useless_stmts}. + +@item Mudflap declaration registration + +If mudflap (@pxref{Optimize Options,,-fmudflap -fmudflapth +-fmudflapir,gcc,Using the GNU Compiler Collection (GCC)}) is +enabled, we generate code to register some variable declarations with +the mudflap runtime. Specifically, the runtime tracks the lifetimes of +those variable declarations that have their addresses taken, or whose +bounds are unknown at compile time (@code{extern}). This pass generates +new exception handling constructs (@code{try}/@code{finally}), and so +must run before those are lowered. In addition, the pass enqueues +declarations of static variables whose lifetimes extend to the entire +program. The pass is located in @file{tree-mudflap.c} and is described +by @code{pass_mudflap_1}. + +@item OpenMP lowering + +If OpenMP generation (@option{-fopenmp}) is enabled, this pass lowers +OpenMP constructs into GIMPLE. + +Lowering of OpenMP constructs involves creating replacement +expressions for local variables that have been mapped using data +sharing clauses, exposing the control flow of most synchronization +directives and adding region markers to facilitate the creation of the +control flow graph. The pass is located in @file{omp-low.c} and is +described by @code{pass_lower_omp}. + +@item OpenMP expansion + +If OpenMP generation (@option{-fopenmp}) is enabled, this pass expands +parallel regions into their own functions to be invoked by the thread +library. The pass is located in @file{omp-low.c} and is described by +@code{pass_expand_omp}. + +@item Lower control flow + +This pass flattens @code{if} statements (@code{COND_EXPR}) +and moves lexical bindings (@code{BIND_EXPR}) out of line. After +this pass, all @code{if} statements will have exactly two @code{goto} +statements in its @code{then} and @code{else} arms. Lexical binding +information for each statement will be found in @code{TREE_BLOCK} rather +than being inferred from its position under a @code{BIND_EXPR}. This +pass is found in @file{gimple-low.c} and is described by +@code{pass_lower_cf}. + +@item Lower exception handling control flow + +This pass decomposes high-level exception handling constructs +(@code{TRY_FINALLY_EXPR} and @code{TRY_CATCH_EXPR}) into a form +that explicitly represents the control flow involved. After this +pass, @code{lookup_stmt_eh_region} will return a non-negative +number for any statement that may have EH control flow semantics; +examine @code{tree_can_throw_internal} or @code{tree_can_throw_external} +for exact semantics. Exact control flow may be extracted from +@code{foreach_reachable_handler}. The EH region nesting tree is defined +in @file{except.h} and built in @file{except.c}. The lowering pass +itself is in @file{tree-eh.c} and is described by @code{pass_lower_eh}. + +@item Build the control flow graph + +This pass decomposes a function into basic blocks and creates all of +the edges that connect them. It is located in @file{tree-cfg.c} and +is described by @code{pass_build_cfg}. + +@item Find all referenced variables + +This pass walks the entire function and collects an array of all +variables referenced in the function, @code{referenced_vars}. The +index at which a variable is found in the array is used as a UID +for the variable within this function. This data is needed by the +SSA rewriting routines. The pass is located in @file{tree-dfa.c} +and is described by @code{pass_referenced_vars}. + +@item Enter static single assignment form + +This pass rewrites the function such that it is in SSA form. After +this pass, all @code{is_gimple_reg} variables will be referenced by +@code{SSA_NAME}, and all occurrences of other variables will be +annotated with @code{VDEFS} and @code{VUSES}; PHI nodes will have +been inserted as necessary for each basic block. This pass is +located in @file{tree-ssa.c} and is described by @code{pass_build_ssa}. + +@item Warn for uninitialized variables + +This pass scans the function for uses of @code{SSA_NAME}s that +are fed by default definition. For non-parameter variables, such +uses are uninitialized. The pass is run twice, before and after +optimization. In the first pass we only warn for uses that are +positively uninitialized; in the second pass we warn for uses that +are possibly uninitialized. The pass is located in @file{tree-ssa.c} +and is defined by @code{pass_early_warn_uninitialized} and +@code{pass_late_warn_uninitialized}. + +@item Dead code elimination + +This pass scans the function for statements without side effects whose +result is unused. It does not do memory life analysis, so any value +that is stored in memory is considered used. The pass is run multiple +times throughout the optimization process. It is located in +@file{tree-ssa-dce.c} and is described by @code{pass_dce}. + +@item Dominator optimizations + +This pass performs trivial dominator-based copy and constant propagation, +expression simplification, and jump threading. It is run multiple times +throughout the optimization process. It it located in @file{tree-ssa-dom.c} +and is described by @code{pass_dominator}. + +@item Redundant PHI elimination + +This pass removes PHI nodes for which all of the arguments are the same +value, excluding feedback. Such degenerate forms are typically created +by removing unreachable code. The pass is run multiple times throughout +the optimization process. It is located in @file{tree-ssa.c} and is +described by @code{pass_redundant_phi}.o + +@item Forward propagation of single-use variables + +This pass attempts to remove redundant computation by substituting +variables that are used once into the expression that uses them and +seeing if the result can be simplified. It is located in +@file{tree-ssa-forwprop.c} and is described by @code{pass_forwprop}. + +@item Copy Renaming + +This pass attempts to change the name of compiler temporaries involved in +copy operations such that SSA->normal can coalesce the copy away. When compiler +temporaries are copies of user variables, it also renames the compiler +temporary to the user variable resulting in better use of user symbols. It is +located in @file{tree-ssa-copyrename.c} and is described by +@code{pass_copyrename}. + +@item PHI node optimizations + +This pass recognizes forms of PHI inputs that can be represented as +conditional expressions and rewrites them into straight line code. +It is located in @file{tree-ssa-phiopt.c} and is described by +@code{pass_phiopt}. + +@item May-alias optimization + +This pass performs a flow sensitive SSA-based points-to analysis. +The resulting may-alias, must-alias, and escape analysis information +is used to promote variables from in-memory addressable objects to +non-aliased variables that can be renamed into SSA form. We also +update the @code{VDEF}/@code{VUSE} memory tags for non-renameable +aggregates so that we get fewer false kills. The pass is located +in @file{tree-ssa-alias.c} and is described by @code{pass_may_alias}. + +Interprocedural points-to information is located in +@file{tree-ssa-structalias.c} and described by @code{pass_ipa_pta}. + +@item Profiling + +This pass rewrites the function in order to collect runtime block +and value profiling data. Such data may be fed back into the compiler +on a subsequent run so as to allow optimization based on expected +execution frequencies. The pass is located in @file{predict.c} and +is described by @code{pass_profile}. + +@item Lower complex arithmetic + +This pass rewrites complex arithmetic operations into their component +scalar arithmetic operations. The pass is located in @file{tree-complex.c} +and is described by @code{pass_lower_complex}. + +@item Scalar replacement of aggregates + +This pass rewrites suitable non-aliased local aggregate variables into +a set of scalar variables. The resulting scalar variables are +rewritten into SSA form, which allows subsequent optimization passes +to do a significantly better job with them. The pass is located in +@file{tree-sra.c} and is described by @code{pass_sra}. + +@item Dead store elimination + +This pass eliminates stores to memory that are subsequently overwritten +by another store, without any intervening loads. The pass is located +in @file{tree-ssa-dse.c} and is described by @code{pass_dse}. + +@item Tail recursion elimination + +This pass transforms tail recursion into a loop. It is located in +@file{tree-tailcall.c} and is described by @code{pass_tail_recursion}. + +@item Forward store motion + +This pass sinks stores and assignments down the flowgraph closer to it's +use point. The pass is located in @file{tree-ssa-sink.c} and is +described by @code{pass_sink_code}. + +@item Partial redundancy elimination + +This pass eliminates partially redundant computations, as well as +performing load motion. The pass is located in @file{tree-ssa-pre.c} +and is described by @code{pass_pre}. + +Just before partial redundancy elimination, if +@option{-funsafe-math-optimizations} is on, GCC tries to convert +divisions to multiplications by the reciprocal. The pass is located +in @file{tree-ssa-math-opts.c} and is described by +@code{pass_cse_reciprocal}. + +@item Full redundancy elimination + +This is a simpler form of PRE that only eliminate redundancies that +occur an all paths. It is located in @file{tree-ssa-pre.c} and +described by @code{pass_fre}. + +@item Loop optimization + +The main driver of the pass is placed in @file{tree-ssa-loop.c} +and described by @code{pass_loop}. + +The optimizations performed by this pass are: + +Loop invariant motion. This pass moves only invariants that +would be hard to handle on rtl level (function calls, operations that expand to +nontrivial sequences of insns). With @option{-funswitch-loops} it also moves +operands of conditions that are invariant out of the loop, so that we can use +just trivial invariantness analysis in loop unswitching. The pass also includes +store motion. The pass is implemented in @file{tree-ssa-loop-im.c}. + +Canonical induction variable creation. This pass creates a simple counter +for number of iterations of the loop and replaces the exit condition of the +loop using it, in case when a complicated analysis is necessary to determine +the number of iterations. Later optimizations then may determine the number +easily. The pass is implemented in @file{tree-ssa-loop-ivcanon.c}. + +Induction variable optimizations. This pass performs standard induction +variable optimizations, including strength reduction, induction variable +merging and induction variable elimination. The pass is implemented in +@file{tree-ssa-loop-ivopts.c}. + +Loop unswitching. This pass moves the conditional jumps that are invariant +out of the loops. To achieve this, a duplicate of the loop is created for +each possible outcome of conditional jump(s). The pass is implemented in +@file{tree-ssa-loop-unswitch.c}. This pass should eventually replace the +rtl-level loop unswitching in @file{loop-unswitch.c}, but currently +the rtl-level pass is not completely redundant yet due to deficiencies +in tree level alias analysis. + +The optimizations also use various utility functions contained in +@file{tree-ssa-loop-manip.c}, @file{cfgloop.c}, @file{cfgloopanal.c} and +@file{cfgloopmanip.c}. + +Vectorization. This pass transforms loops to operate on vector types +instead of scalar types. Data parallelism across loop iterations is exploited +to group data elements from consecutive iterations into a vector and operate +on them in parallel. Depending on available target support the loop is +conceptually unrolled by a factor @code{VF} (vectorization factor), which is +the number of elements operated upon in parallel in each iteration, and the +@code{VF} copies of each scalar operation are fused to form a vector operation. +Additional loop transformations such as peeling and versioning may take place +to align the number of iterations, and to align the memory accesses in the loop. +The pass is implemented in @file{tree-vectorizer.c} (the main driver and general +utilities), @file{tree-vect-analyze.c} and @file{tree-vect-transform.c}. +Analysis of data references is in @file{tree-data-ref.c}. + +@item Tree level if-conversion for vectorizer + +This pass applies if-conversion to simple loops to help vectorizer. +We identify if convertible loops, if-convert statements and merge +basic blocks in one big block. The idea is to present loop in such +form so that vectorizer can have one to one mapping between statements +and available vector operations. This patch re-introduces COND_EXPR +at GIMPLE level. This pass is located in @file{tree-if-conv.c} and is +described by @code{pass_if_conversion}. + +@item Conditional constant propagation + +This pass relaxes a lattice of values in order to identify those +that must be constant even in the presence of conditional branches. +The pass is located in @file{tree-ssa-ccp.c} and is described +by @code{pass_ccp}. + +A related pass that works on memory loads and stores, and not just +register values, is located in @file{tree-ssa-ccp.c} and described by +@code{pass_store_ccp}. + +@item Conditional copy propagation + +This is similar to constant propagation but the lattice of values is +the ``copy-of'' relation. It eliminates redundant copies from the +code. The pass is located in @file{tree-ssa-copy.c} and described by +@code{pass_copy_prop}. + +A related pass that works on memory copies, and not just register +copies, is located in @file{tree-ssa-copy.c} and described by +@code{pass_store_copy_prop}. + +@item Value range propagation + +This transformation is similar to constant propagation but +instead of propagating single constant values, it propagates +known value ranges. The implementation is based on Patterson's +range propagation algorithm (Accurate Static Branch Prediction by +Value Range Propagation, J. R. C. Patterson, PLDI '95). In +contrast to Patterson's algorithm, this implementation does not +propagate branch probabilities nor it uses more than a single +range per SSA name. This means that the current implementation +cannot be used for branch prediction (though adapting it would +not be difficult). The pass is located in @file{tree-vrp.c} and is +described by @code{pass_vrp}. + +@item Folding built-in functions + +This pass simplifies built-in functions, as applicable, with constant +arguments or with inferrable string lengths. It is located in +@file{tree-ssa-ccp.c} and is described by @code{pass_fold_builtins}. + +@item Split critical edges + +This pass identifies critical edges and inserts empty basic blocks +such that the edge is no longer critical. The pass is located in +@file{tree-cfg.c} and is described by @code{pass_split_crit_edges}. + +@item Control dependence dead code elimination + +This pass is a stronger form of dead code elimination that can +eliminate unnecessary control flow statements. It is located +in @file{tree-ssa-dce.c} and is described by @code{pass_cd_dce}. + +@item Tail call elimination + +This pass identifies function calls that may be rewritten into +jumps. No code transformation is actually applied here, but the +data and control flow problem is solved. The code transformation +requires target support, and so is delayed until RTL@. In the +meantime @code{CALL_EXPR_TAILCALL} is set indicating the possibility. +The pass is located in @file{tree-tailcall.c} and is described by +@code{pass_tail_calls}. The RTL transformation is handled by +@code{fixup_tail_calls} in @file{calls.c}. + +@item Warn for function return without value + +For non-void functions, this pass locates return statements that do +not specify a value and issues a warning. Such a statement may have +been injected by falling off the end of the function. This pass is +run last so that we have as much time as possible to prove that the +statement is not reachable. It is located in @file{tree-cfg.c} and +is described by @code{pass_warn_function_return}. + +@item Mudflap statement annotation + +If mudflap is enabled, we rewrite some memory accesses with code to +validate that the memory access is correct. In particular, expressions +involving pointer dereferences (@code{INDIRECT_REF}, @code{ARRAY_REF}, +etc.) are replaced by code that checks the selected address range +against the mudflap runtime's database of valid regions. This check +includes an inline lookup into a direct-mapped cache, based on +shift/mask operations of the pointer value, with a fallback function +call into the runtime. The pass is located in @file{tree-mudflap.c} and +is described by @code{pass_mudflap_2}. + +@item Leave static single assignment form + +This pass rewrites the function such that it is in normal form. At +the same time, we eliminate as many single-use temporaries as possible, +so the intermediate language is no longer GIMPLE, but GENERIC@. The +pass is located in @file{tree-outof-ssa.c} and is described by +@code{pass_del_ssa}. + +@item Merge PHI nodes that feed into one another + +This is part of the CFG cleanup passes. It attempts to join PHI nodes +from a forwarder CFG block into another block with PHI nodes. The +pass is located in @file{tree-cfgcleanup.c} and is described by +@code{pass_merge_phi}. + +@item Return value optimization + +If a function always returns the same local variable, and that local +variable is an aggregate type, then the variable is replaced with the +return value for the function (i.e., the function's DECL_RESULT). This +is equivalent to the C++ named return value optimization applied to +GIMPLE. The pass is located in @file{tree-nrv.c} and is described by +@code{pass_nrv}. + +@item Return slot optimization + +If a function returns a memory object and is called as @code{var = +foo()}, this pass tries to change the call so that the address of +@code{var} is sent to the caller to avoid an extra memory copy. This +pass is located in @code{tree-nrv.c} and is described by +@code{pass_return_slot}. + +@item Optimize calls to @code{__builtin_object_size} + +This is a propagation pass similar to CCP that tries to remove calls +to @code{__builtin_object_size} when the size of the object can be +computed at compile-time. This pass is located in +@file{tree-object-size.c} and is described by +@code{pass_object_sizes}. + +@item Loop invariant motion + +This pass removes expensive loop-invariant computations out of loops. +The pass is located in @file{tree-ssa-loop.c} and described by +@code{pass_lim}. + +@item Loop nest optimizations + +This is a family of loop transformations that works on loop nests. It +includes loop interchange, scaling, skewing and reversal and they are +all geared to the optimization of data locality in array traversals +and the removal of dependencies that hamper optimizations such as loop +parallelization and vectorization. The pass is located in +@file{tree-loop-linear.c} and described by +@code{pass_linear_transform}. + +@item Removal of empty loops + +This pass removes loops with no code in them. The pass is located in +@file{tree-ssa-loop-ivcanon.c} and described by +@code{pass_empty_loop}. + +@item Unrolling of small loops + +This pass completely unrolls loops with few iterations. The pass +is located in @file{tree-ssa-loop-ivcanon.c} and described by +@code{pass_complete_unroll}. + +@item Array prefetching + +This pass issues prefetch instructions for array references inside +loops. The pass is located in @file{tree-ssa-loop-prefetch.c} and +described by @code{pass_loop_prefetch}. + +@item Reassociation + +This pass rewrites arithmetic expressions to enable optimizations that +operate on them, like redundancy elimination and vectorization. The +pass is located in @file{tree-ssa-reassoc.c} and described by +@code{pass_reassoc}. + +@item Optimization of @code{stdarg} functions + +This pass tries to avoid the saving of register arguments into the +stack on entry to @code{stdarg} functions. If the function doesn't +use any @code{va_start} macros, no registers need to be saved. If +@code{va_start} macros are used, the @code{va_list} variables don't +escape the function, it is only necessary to save registers that will +be used in @code{va_arg} macros. For instance, if @code{va_arg} is +only used with integral types in the function, floating point +registers don't need to be saved. This pass is located in +@code{tree-stdarg.c} and described by @code{pass_stdarg}. + +@end itemize + +@node RTL passes +@section RTL passes + +The following briefly describes the rtl generation and optimization +passes that are run after tree optimization. + +@itemize @bullet +@item RTL generation + +@c Avoiding overfull is tricky here. +The source files for RTL generation include +@file{stmt.c}, +@file{calls.c}, +@file{expr.c}, +@file{explow.c}, +@file{expmed.c}, +@file{function.c}, +@file{optabs.c} +and @file{emit-rtl.c}. +Also, the file +@file{insn-emit.c}, generated from the machine description by the +program @code{genemit}, is used in this pass. The header file +@file{expr.h} is used for communication within this pass. + +@findex genflags +@findex gencodes +The header files @file{insn-flags.h} and @file{insn-codes.h}, +generated from the machine description by the programs @code{genflags} +and @code{gencodes}, tell this pass which standard names are available +for use and which patterns correspond to them. + +@item Generate exception handling landing pads + +This pass generates the glue that handles communication between the +exception handling library routines and the exception handlers within +the function. Entry points in the function that are invoked by the +exception handling library are called @dfn{landing pads}. The code +for this pass is located within @file{except.c}. + +@item Cleanup control flow graph + +This pass removes unreachable code, simplifies jumps to next, jumps to +jump, jumps across jumps, etc. The pass is run multiple times. +For historical reasons, it is occasionally referred to as the ``jump +optimization pass''. The bulk of the code for this pass is in +@file{cfgcleanup.c}, and there are support routines in @file{cfgrtl.c} +and @file{jump.c}. + +@item Common subexpression elimination + +This pass removes redundant computation within basic blocks, and +optimizes addressing modes based on cost. The pass is run twice. +The source is located in @file{cse.c}. + +@item Global common subexpression elimination. + +This pass performs two +different types of GCSE depending on whether you are optimizing for +size or not (LCM based GCSE tends to increase code size for a gain in +speed, while Morel-Renvoise based GCSE does not). +When optimizing for size, GCSE is done using Morel-Renvoise Partial +Redundancy Elimination, with the exception that it does not try to move +invariants out of loops---that is left to the loop optimization pass. +If MR PRE GCSE is done, code hoisting (aka unification) is also done, as +well as load motion. +If you are optimizing for speed, LCM (lazy code motion) based GCSE is +done. LCM is based on the work of Knoop, Ruthing, and Steffen. LCM +based GCSE also does loop invariant code motion. We also perform load +and store motion when optimizing for speed. +Regardless of which type of GCSE is used, the GCSE pass also performs +global constant and copy propagation. +The source file for this pass is @file{gcse.c}, and the LCM routines +are in @file{lcm.c}. + +@item Loop optimization + +This pass performs several loop related optimizations. +The source files @file{cfgloopanal.c} and @file{cfgloopmanip.c} contain +generic loop analysis and manipulation code. Initialization and finalization +of loop structures is handled by @file{loop-init.c}. +A loop invariant motion pass is implemented in @file{loop-invariant.c}. +Basic block level optimizations---unrolling, peeling and unswitching loops--- +are implemented in @file{loop-unswitch.c} and @file{loop-unroll.c}. +Replacing of the exit condition of loops by special machine-dependent +instructions is handled by @file{loop-doloop.c}. + +@item Jump bypassing + +This pass is an aggressive form of GCSE that transforms the control +flow graph of a function by propagating constants into conditional +branch instructions. The source file for this pass is @file{gcse.c}. + +@item If conversion + +This pass attempts to replace conditional branches and surrounding +assignments with arithmetic, boolean value producing comparison +instructions, and conditional move instructions. In the very last +invocation after reload, it will generate predicated instructions +when supported by the target. The pass is located in @file{ifcvt.c}. + +@item Web construction + +This pass splits independent uses of each pseudo-register. This can +improve effect of the other transformation, such as CSE or register +allocation. Its source files are @file{web.c}. + +@item Life analysis + +This pass computes which pseudo-registers are live at each point in +the program, and makes the first instruction that uses a value point +at the instruction that computed the value. It then deletes +computations whose results are never used, and combines memory +references with add or subtract instructions to make autoincrement or +autodecrement addressing. The pass is located in @file{flow.c}. + +@item Instruction combination + +This pass attempts to combine groups of two or three instructions that +are related by data flow into single instructions. It combines the +RTL expressions for the instructions by substitution, simplifies the +result using algebra, and then attempts to match the result against +the machine description. The pass is located in @file{combine.c}. + +@item Register movement + +This pass looks for cases where matching constraints would force an +instruction to need a reload, and this reload would be a +register-to-register move. It then attempts to change the registers +used by the instruction to avoid the move instruction. +The pass is located in @file{regmove.c}. + +@item Optimize mode switching + +This pass looks for instructions that require the processor to be in a +specific ``mode'' and minimizes the number of mode changes required to +satisfy all users. What these modes are, and what they apply to are +completely target-specific. +The source is located in @file{mode-switching.c}. + +@cindex modulo scheduling +@cindex sms, swing, software pipelining +@item Modulo scheduling + +This pass looks at innermost loops and reorders their instructions +by overlapping different iterations. Modulo scheduling is performed +immediately before instruction scheduling. +The pass is located in (@file{modulo-sched.c}). + +@item Instruction scheduling + +This pass looks for instructions whose output will not be available by +the time that it is used in subsequent instructions. Memory loads and +floating point instructions often have this behavior on RISC machines. +It re-orders instructions within a basic block to try to separate the +definition and use of items that otherwise would cause pipeline +stalls. This pass is performed twice, before and after register +allocation. The pass is located in @file{haifa-sched.c}, +@file{sched-deps.c}, @file{sched-ebb.c}, @file{sched-rgn.c} and +@file{sched-vis.c}. + +@item Register allocation + +These passes make sure that all occurrences of pseudo registers are +eliminated, either by allocating them to a hard register, replacing +them by an equivalent expression (e.g.@: a constant) or by placing +them on the stack. This is done in several subpasses: + +@itemize @bullet +@item +Register class preferencing. The RTL code is scanned to find out +which register class is best for each pseudo register. The source +file is @file{regclass.c}. + +@item +Local register allocation. This pass allocates hard registers to +pseudo registers that are used only within one basic block. Because +the basic block is linear, it can use fast and powerful techniques to +do a decent job. The source is located in @file{local-alloc.c}. + +@item +Global register allocation. This pass allocates hard registers for +the remaining pseudo registers (those whose life spans are not +contained in one basic block). The pass is located in @file{global.c}. + +@cindex reloading +@item +Reloading. This pass renumbers pseudo registers with the hardware +registers numbers they were allocated. Pseudo registers that did not +get hard registers are replaced with stack slots. Then it finds +instructions that are invalid because a value has failed to end up in +a register, or has ended up in a register of the wrong kind. It fixes +up these instructions by reloading the problematical values +temporarily into registers. Additional instructions are generated to +do the copying. + +The reload pass also optionally eliminates the frame pointer and inserts +instructions to save and restore call-clobbered registers around calls. + +Source files are @file{reload.c} and @file{reload1.c}, plus the header +@file{reload.h} used for communication between them. +@end itemize + +@item Basic block reordering + +This pass implements profile guided code positioning. If profile +information is not available, various types of static analysis are +performed to make the predictions normally coming from the profile +feedback (IE execution frequency, branch probability, etc). It is +implemented in the file @file{bb-reorder.c}, and the various +prediction routines are in @file{predict.c}. + +@item Variable tracking + +This pass computes where the variables are stored at each +position in code and generates notes describing the variable locations +to RTL code. The location lists are then generated according to these +notes to debug information if the debugging information format supports +location lists. + +@item Delayed branch scheduling + +This optional pass attempts to find instructions that can go into the +delay slots of other instructions, usually jumps and calls. The +source file name is @file{reorg.c}. + +@item Branch shortening + +On many RISC machines, branch instructions have a limited range. +Thus, longer sequences of instructions must be used for long branches. +In this pass, the compiler figures out what how far each instruction +will be from each other instruction, and therefore whether the usual +instructions, or the longer sequences, must be used for each branch. + +@item Register-to-stack conversion + +Conversion from usage of some hard registers to usage of a register +stack may be done at this point. Currently, this is supported only +for the floating-point registers of the Intel 80387 coprocessor. The +source file name is @file{reg-stack.c}. + +@item Final + +This pass outputs the assembler code for the function. The source files +are @file{final.c} plus @file{insn-output.c}; the latter is generated +automatically from the machine description by the tool @file{genoutput}. +The header file @file{conditions.h} is used for communication between +these files. If mudflap is enabled, the queue of deferred declarations +and any addressed constants (e.g., string literals) is processed by +@code{mudflap_finish_file} into a synthetic constructor function +containing calls into the mudflap runtime. + +@item Debugging information output + +This is run after final because it must output the stack slot offsets +for pseudo registers that did not get hard registers. Source files +are @file{dbxout.c} for DBX symbol table format, @file{sdbout.c} for +SDB symbol table format, @file{dwarfout.c} for DWARF symbol table +format, files @file{dwarf2out.c} and @file{dwarf2asm.c} for DWARF2 +symbol table format, and @file{vmsdbgout.c} for VMS debug symbol table +format. + +@end itemize diff --git a/gcc-4.2.1-5666.3/gcc/doc/portability.texi b/gcc-4.2.1-5666.3/gcc/doc/portability.texi new file mode 100644 index 000000000..c5f8048fa --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/portability.texi @@ -0,0 +1,40 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Portability +@chapter GCC and Portability +@cindex portability +@cindex GCC and portability + +GCC itself aims to be portable to any machine where @code{int} is at least +a 32-bit type. It aims to target machines with a flat (non-segmented) byte +addressed data address space (the code address space can be separate). +Target ABIs may have 8, 16, 32 or 64-bit @code{int} type. @code{char} +can be wider than 8 bits. + +GCC gets most of the information about the target machine from a machine +description which gives an algebraic formula for each of the machine's +instructions. This is a very clean way to describe the target. But when +the compiler needs information that is difficult to express in this +fashion, ad-hoc parameters have been defined for machine descriptions. +The purpose of portability is to reduce the total work needed on the +compiler; it was not of interest for its own sake. + +@cindex endianness +@cindex autoincrement addressing, availability +@findex abort +GCC does not contain machine dependent code, but it does contain code +that depends on machine parameters such as endianness (whether the most +significant byte has the highest or lowest address of the bytes in a word) +and the availability of autoincrement addressing. In the RTL-generation +pass, it is often necessary to have multiple strategies for generating code +for a particular kind of syntax tree, strategies that are usable for different +combinations of parameters. Often, not all possible cases have been +addressed, but only the common ones or only the ones that have been +encountered. As a result, a new target may require additional +strategies. You will know +if this happens because the compiler will call @code{abort}. Fortunately, +the new strategies can be added in a machine-independent fashion, and will +affect only the target machines that need them. diff --git a/gcc-4.2.1-5666.3/gcc/doc/rtl.texi b/gcc-4.2.1-5666.3/gcc/doc/rtl.texi new file mode 100644 index 000000000..76e8f16fa --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/rtl.texi @@ -0,0 +1,3722 @@ +@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002, +@c 2003, 2004, 2005 +@c Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node RTL +@chapter RTL Representation +@cindex RTL representation +@cindex representation of RTL +@cindex Register Transfer Language (RTL) + +Most of the work of the compiler is done on an intermediate representation +called register transfer language. In this language, the instructions to be +output are described, pretty much one by one, in an algebraic form that +describes what the instruction does. + +RTL is inspired by Lisp lists. It has both an internal form, made up of +structures that point at other structures, and a textual form that is used +in the machine description and in printed debugging dumps. The textual +form uses nested parentheses to indicate the pointers in the internal form. + +@menu +* RTL Objects:: Expressions vs vectors vs strings vs integers. +* RTL Classes:: Categories of RTL expression objects, and their structure. +* Accessors:: Macros to access expression operands or vector elts. +* Special Accessors:: Macros to access specific annotations on RTL. +* Flags:: Other flags in an RTL expression. +* Machine Modes:: Describing the size and format of a datum. +* Constants:: Expressions with constant values. +* Regs and Memory:: Expressions representing register contents or memory. +* Arithmetic:: Expressions representing arithmetic on other expressions. +* Comparisons:: Expressions representing comparison of expressions. +* Bit-Fields:: Expressions representing bit-fields in memory or reg. +* Vector Operations:: Expressions involving vector datatypes. +* Conversions:: Extending, truncating, floating or fixing. +* RTL Declarations:: Declaring volatility, constancy, etc. +* Side Effects:: Expressions for storing in registers, etc. +* Incdec:: Embedded side-effects for autoincrement addressing. +* Assembler:: Representing @code{asm} with operands. +* Insns:: Expression types for entire insns. +* Calls:: RTL representation of function call insns. +* Sharing:: Some expressions are unique; others *must* be copied. +* Reading RTL:: Reading textual RTL from a file. +@end menu + +@node RTL Objects +@section RTL Object Types +@cindex RTL object types + +@cindex RTL integers +@cindex RTL strings +@cindex RTL vectors +@cindex RTL expression +@cindex RTX (See RTL) +RTL uses five kinds of objects: expressions, integers, wide integers, +strings and vectors. Expressions are the most important ones. An RTL +expression (``RTX'', for short) is a C structure, but it is usually +referred to with a pointer; a type that is given the typedef name +@code{rtx}. + +An integer is simply an @code{int}; their written form uses decimal +digits. A wide integer is an integral object whose type is +@code{HOST_WIDE_INT}; their written form uses decimal digits. + +A string is a sequence of characters. In core it is represented as a +@code{char *} in usual C fashion, and it is written in C syntax as well. +However, strings in RTL may never be null. If you write an empty string in +a machine description, it is represented in core as a null pointer rather +than as a pointer to a null character. In certain contexts, these null +pointers instead of strings are valid. Within RTL code, strings are most +commonly found inside @code{symbol_ref} expressions, but they appear in +other contexts in the RTL expressions that make up machine descriptions. + +In a machine description, strings are normally written with double +quotes, as you would in C@. However, strings in machine descriptions may +extend over many lines, which is invalid C, and adjacent string +constants are not concatenated as they are in C@. Any string constant +may be surrounded with a single set of parentheses. Sometimes this +makes the machine description easier to read. + +There is also a special syntax for strings, which can be useful when C +code is embedded in a machine description. Wherever a string can +appear, it is also valid to write a C-style brace block. The entire +brace block, including the outermost pair of braces, is considered to be +the string constant. Double quote characters inside the braces are not +special. Therefore, if you write string constants in the C code, you +need not escape each quote character with a backslash. + +A vector contains an arbitrary number of pointers to expressions. The +number of elements in the vector is explicitly present in the vector. +The written form of a vector consists of square brackets +(@samp{[@dots{}]}) surrounding the elements, in sequence and with +whitespace separating them. Vectors of length zero are not created; +null pointers are used instead. + +@cindex expression codes +@cindex codes, RTL expression +@findex GET_CODE +@findex PUT_CODE +Expressions are classified by @dfn{expression codes} (also called RTX +codes). The expression code is a name defined in @file{rtl.def}, which is +also (in uppercase) a C enumeration constant. The possible expression +codes and their meanings are machine-independent. The code of an RTX can +be extracted with the macro @code{GET_CODE (@var{x})} and altered with +@code{PUT_CODE (@var{x}, @var{newcode})}. + +The expression code determines how many operands the expression contains, +and what kinds of objects they are. In RTL, unlike Lisp, you cannot tell +by looking at an operand what kind of object it is. Instead, you must know +from its context---from the expression code of the containing expression. +For example, in an expression of code @code{subreg}, the first operand is +to be regarded as an expression and the second operand as an integer. In +an expression of code @code{plus}, there are two operands, both of which +are to be regarded as expressions. In a @code{symbol_ref} expression, +there is one operand, which is to be regarded as a string. + +Expressions are written as parentheses containing the name of the +expression type, its flags and machine mode if any, and then the operands +of the expression (separated by spaces). + +Expression code names in the @samp{md} file are written in lowercase, +but when they appear in C code they are written in uppercase. In this +manual, they are shown as follows: @code{const_int}. + +@cindex (nil) +@cindex nil +In a few contexts a null pointer is valid where an expression is normally +wanted. The written form of this is @code{(nil)}. + +@node RTL Classes +@section RTL Classes and Formats +@cindex RTL classes +@cindex classes of RTX codes +@cindex RTX codes, classes of +@findex GET_RTX_CLASS + +The various expression codes are divided into several @dfn{classes}, +which are represented by single characters. You can determine the class +of an RTX code with the macro @code{GET_RTX_CLASS (@var{code})}. +Currently, @file{rtl.def} defines these classes: + +@table @code +@item RTX_OBJ +An RTX code that represents an actual object, such as a register +(@code{REG}) or a memory location (@code{MEM}, @code{SYMBOL_REF}). +@code{LO_SUM}) is also included; instead, @code{SUBREG} and +@code{STRICT_LOW_PART} are not in this class, but in class @code{x}. + +@item RTX_CONST_OBJ +An RTX code that represents a constant object. @code{HIGH} is also +included in this class. + +@item RTX_COMPARE +An RTX code for a non-symmetric comparison, such as @code{GEU} or +@code{LT}. + +@item RTX_COMM_COMPARE +An RTX code for a symmetric (commutative) comparison, such as @code{EQ} +or @code{ORDERED}. + +@item RTX_UNARY +An RTX code for a unary arithmetic operation, such as @code{NEG}, +@code{NOT}, or @code{ABS}. This category also includes value extension +(sign or zero) and conversions between integer and floating point. + +@item RTX_COMM_ARITH +An RTX code for a commutative binary operation, such as @code{PLUS} or +@code{AND}. @code{NE} and @code{EQ} are comparisons, so they have class +@code{<}. + +@item RTX_BIN_ARITH +An RTX code for a non-commutative binary operation, such as @code{MINUS}, +@code{DIV}, or @code{ASHIFTRT}. + +@item RTX_BITFIELD_OPS +An RTX code for a bit-field operation. Currently only +@code{ZERO_EXTRACT} and @code{SIGN_EXTRACT}. These have three inputs +and are lvalues (so they can be used for insertion as well). +@xref{Bit-Fields}. + +@item RTX_TERNARY +An RTX code for other three input operations. Currently only +@code{IF_THEN_ELSE} and @code{VEC_MERGE}. + +@item RTX_INSN +An RTX code for an entire instruction: @code{INSN}, @code{JUMP_INSN}, and +@code{CALL_INSN}. @xref{Insns}. + +@item RTX_MATCH +An RTX code for something that matches in insns, such as +@code{MATCH_DUP}. These only occur in machine descriptions. + +@item RTX_AUTOINC +An RTX code for an auto-increment addressing mode, such as +@code{POST_INC}. + +@item RTX_EXTRA +All other RTX codes. This category includes the remaining codes used +only in machine descriptions (@code{DEFINE_*}, etc.). It also includes +all the codes describing side effects (@code{SET}, @code{USE}, +@code{CLOBBER}, etc.) and the non-insns that may appear on an insn +chain, such as @code{NOTE}, @code{BARRIER}, and @code{CODE_LABEL}. +@code{SUBREG} is also part of this class. +@end table + +@cindex RTL format +For each expression code, @file{rtl.def} specifies the number of +contained objects and their kinds using a sequence of characters +called the @dfn{format} of the expression code. For example, +the format of @code{subreg} is @samp{ei}. + +@cindex RTL format characters +These are the most commonly used format characters: + +@table @code +@item e +An expression (actually a pointer to an expression). + +@item i +An integer. + +@item w +A wide integer. + +@item s +A string. + +@item E +A vector of expressions. +@end table + +A few other format characters are used occasionally: + +@table @code +@item u +@samp{u} is equivalent to @samp{e} except that it is printed differently +in debugging dumps. It is used for pointers to insns. + +@item n +@samp{n} is equivalent to @samp{i} except that it is printed differently +in debugging dumps. It is used for the line number or code number of a +@code{note} insn. + +@item S +@samp{S} indicates a string which is optional. In the RTL objects in +core, @samp{S} is equivalent to @samp{s}, but when the object is read, +from an @samp{md} file, the string value of this operand may be omitted. +An omitted string is taken to be the null string. + +@item V +@samp{V} indicates a vector which is optional. In the RTL objects in +core, @samp{V} is equivalent to @samp{E}, but when the object is read +from an @samp{md} file, the vector value of this operand may be omitted. +An omitted vector is effectively the same as a vector of no elements. + +@item B +@samp{B} indicates a pointer to basic block structure. + +@item 0 +@samp{0} means a slot whose contents do not fit any normal category. +@samp{0} slots are not printed at all in dumps, and are often used in +special ways by small parts of the compiler. +@end table + +There are macros to get the number of operands and the format +of an expression code: + +@table @code +@findex GET_RTX_LENGTH +@item GET_RTX_LENGTH (@var{code}) +Number of operands of an RTX of code @var{code}. + +@findex GET_RTX_FORMAT +@item GET_RTX_FORMAT (@var{code}) +The format of an RTX of code @var{code}, as a C string. +@end table + +Some classes of RTX codes always have the same format. For example, it +is safe to assume that all comparison operations have format @code{ee}. + +@table @code +@item 1 +All codes of this class have format @code{e}. + +@item < +@itemx c +@itemx 2 +All codes of these classes have format @code{ee}. + +@item b +@itemx 3 +All codes of these classes have format @code{eee}. + +@item i +All codes of this class have formats that begin with @code{iuueiee}. +@xref{Insns}. Note that not all RTL objects linked onto an insn chain +are of class @code{i}. + +@item o +@itemx m +@itemx x +You can make no assumptions about the format of these codes. +@end table + +@node Accessors +@section Access to Operands +@cindex accessors +@cindex access to operands +@cindex operand access + +@findex XEXP +@findex XINT +@findex XWINT +@findex XSTR +Operands of expressions are accessed using the macros @code{XEXP}, +@code{XINT}, @code{XWINT} and @code{XSTR}. Each of these macros takes +two arguments: an expression-pointer (RTX) and an operand number +(counting from zero). Thus, + +@smallexample +XEXP (@var{x}, 2) +@end smallexample + +@noindent +accesses operand 2 of expression @var{x}, as an expression. + +@smallexample +XINT (@var{x}, 2) +@end smallexample + +@noindent +accesses the same operand as an integer. @code{XSTR}, used in the same +fashion, would access it as a string. + +Any operand can be accessed as an integer, as an expression or as a string. +You must choose the correct method of access for the kind of value actually +stored in the operand. You would do this based on the expression code of +the containing expression. That is also how you would know how many +operands there are. + +For example, if @var{x} is a @code{subreg} expression, you know that it has +two operands which can be correctly accessed as @code{XEXP (@var{x}, 0)} +and @code{XINT (@var{x}, 1)}. If you did @code{XINT (@var{x}, 0)}, you +would get the address of the expression operand but cast as an integer; +that might occasionally be useful, but it would be cleaner to write +@code{(int) XEXP (@var{x}, 0)}. @code{XEXP (@var{x}, 1)} would also +compile without error, and would return the second, integer operand cast as +an expression pointer, which would probably result in a crash when +accessed. Nothing stops you from writing @code{XEXP (@var{x}, 28)} either, +but this will access memory past the end of the expression with +unpredictable results. + +Access to operands which are vectors is more complicated. You can use the +macro @code{XVEC} to get the vector-pointer itself, or the macros +@code{XVECEXP} and @code{XVECLEN} to access the elements and length of a +vector. + +@table @code +@findex XVEC +@item XVEC (@var{exp}, @var{idx}) +Access the vector-pointer which is operand number @var{idx} in @var{exp}. + +@findex XVECLEN +@item XVECLEN (@var{exp}, @var{idx}) +Access the length (number of elements) in the vector which is +in operand number @var{idx} in @var{exp}. This value is an @code{int}. + +@findex XVECEXP +@item XVECEXP (@var{exp}, @var{idx}, @var{eltnum}) +Access element number @var{eltnum} in the vector which is +in operand number @var{idx} in @var{exp}. This value is an RTX@. + +It is up to you to make sure that @var{eltnum} is not negative +and is less than @code{XVECLEN (@var{exp}, @var{idx})}. +@end table + +All the macros defined in this section expand into lvalues and therefore +can be used to assign the operands, lengths and vector elements as well as +to access them. + +@node Special Accessors +@section Access to Special Operands +@cindex access to special operands + +Some RTL nodes have special annotations associated with them. + +@table @code +@item MEM +@table @code +@findex MEM_ALIAS_SET +@item MEM_ALIAS_SET (@var{x}) +If 0, @var{x} is not in any alias set, and may alias anything. Otherwise, +@var{x} can only alias @code{MEM}s in a conflicting alias set. This value +is set in a language-dependent manner in the front-end, and should not be +altered in the back-end. In some front-ends, these numbers may correspond +in some way to types, or other language-level entities, but they need not, +and the back-end makes no such assumptions. +These set numbers are tested with @code{alias_sets_conflict_p}. + +@findex MEM_EXPR +@item MEM_EXPR (@var{x}) +If this register is known to hold the value of some user-level +declaration, this is that tree node. It may also be a +@code{COMPONENT_REF}, in which case this is some field reference, +and @code{TREE_OPERAND (@var{x}, 0)} contains the declaration, +or another @code{COMPONENT_REF}, or null if there is no compile-time +object associated with the reference. + +@findex MEM_OFFSET +@item MEM_OFFSET (@var{x}) +The offset from the start of @code{MEM_EXPR} as a @code{CONST_INT} rtx. + +@findex MEM_SIZE +@item MEM_SIZE (@var{x}) +The size in bytes of the memory reference as a @code{CONST_INT} rtx. +This is mostly relevant for @code{BLKmode} references as otherwise +the size is implied by the mode. + +@findex MEM_ALIGN +@item MEM_ALIGN (@var{x}) +The known alignment in bits of the memory reference. +@end table + +@item REG +@table @code +@findex ORIGINAL_REGNO +@item ORIGINAL_REGNO (@var{x}) +This field holds the number the register ``originally'' had; for a +pseudo register turned into a hard reg this will hold the old pseudo +register number. + +@findex REG_EXPR +@item REG_EXPR (@var{x}) +If this register is known to hold the value of some user-level +declaration, this is that tree node. + +@findex REG_OFFSET +@item REG_OFFSET (@var{x}) +If this register is known to hold the value of some user-level +declaration, this is the offset into that logical storage. +@end table + +@item SYMBOL_REF +@table @code +@findex SYMBOL_REF_DECL +@item SYMBOL_REF_DECL (@var{x}) +If the @code{symbol_ref} @var{x} was created for a @code{VAR_DECL} or +a @code{FUNCTION_DECL}, that tree is recorded here. If this value is +null, then @var{x} was created by back end code generation routines, +and there is no associated front end symbol table entry. + +@code{SYMBOL_REF_DECL} may also point to a tree of class @code{'c'}, +that is, some sort of constant. In this case, the @code{symbol_ref} +is an entry in the per-file constant pool; again, there is no associated +front end symbol table entry. + +@findex SYMBOL_REF_CONSTANT +@item SYMBOL_REF_CONSTANT (@var{x}) +If @samp{CONSTANT_POOL_ADDRESS_P (@var{x})} is true, this is the constant +pool entry for @var{x}. It is null otherwise. + +@findex SYMBOL_REF_DATA +@item SYMBOL_REF_DATA (@var{x}) +A field of opaque type used to store @code{SYMBOL_REF_DECL} or +@code{SYMBOL_REF_CONSTANT}. + +@findex SYMBOL_REF_FLAGS +@item SYMBOL_REF_FLAGS (@var{x}) +In a @code{symbol_ref}, this is used to communicate various predicates +about the symbol. Some of these are common enough to be computed by +common code, some are specific to the target. The common bits are: + +@table @code +@findex SYMBOL_REF_FUNCTION_P +@findex SYMBOL_FLAG_FUNCTION +@item SYMBOL_FLAG_FUNCTION +Set if the symbol refers to a function. + +@findex SYMBOL_REF_LOCAL_P +@findex SYMBOL_FLAG_LOCAL +@item SYMBOL_FLAG_LOCAL +Set if the symbol is local to this ``module''. +See @code{TARGET_BINDS_LOCAL_P}. + +@findex SYMBOL_REF_EXTERNAL_P +@findex SYMBOL_FLAG_EXTERNAL +@item SYMBOL_FLAG_EXTERNAL +Set if this symbol is not defined in this translation unit. +Note that this is not the inverse of @code{SYMBOL_FLAG_LOCAL}. + +@findex SYMBOL_REF_SMALL_P +@findex SYMBOL_FLAG_SMALL +@item SYMBOL_FLAG_SMALL +Set if the symbol is located in the small data section. +See @code{TARGET_IN_SMALL_DATA_P}. + +@findex SYMBOL_FLAG_TLS_SHIFT +@findex SYMBOL_REF_TLS_MODEL +@item SYMBOL_REF_TLS_MODEL (@var{x}) +This is a multi-bit field accessor that returns the @code{tls_model} +to be used for a thread-local storage symbol. It returns zero for +non-thread-local symbols. + +@findex SYMBOL_REF_HAS_BLOCK_INFO_P +@findex SYMBOL_FLAG_HAS_BLOCK_INFO +@item SYMBOL_FLAG_HAS_BLOCK_INFO +Set if the symbol has @code{SYMBOL_REF_BLOCK} and +@code{SYMBOL_REF_BLOCK_OFFSET} fields. + +@findex SYMBOL_REF_ANCHOR_P +@findex SYMBOL_FLAG_ANCHOR +@cindex @option{-fsection-anchors} +@item SYMBOL_FLAG_ANCHOR +Set if the symbol is used as a section anchor. ``Section anchors'' +are symbols that have a known position within an @code{object_block} +and that can be used to access nearby members of that block. +They are used to implement @option{-fsection-anchors}. + +If this flag is set, then @code{SYMBOL_FLAG_HAS_BLOCK_INFO} will be too. +@end table + +Bits beginning with @code{SYMBOL_FLAG_MACH_DEP} are available for +the target's use. +@end table + +@findex SYMBOL_REF_BLOCK +@item SYMBOL_REF_BLOCK (@var{x}) +If @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})}, this is the +@samp{object_block} structure to which the symbol belongs, +or @code{NULL} if it has not been assigned a block. + +@findex SYMBOL_REF_BLOCK_OFFSET +@item SYMBOL_REF_BLOCK_OFFSET (@var{x}) +If @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})}, this is the offset of @var{x} +from the first object in @samp{SYMBOL_REF_BLOCK (@var{x})}. The value is +negative if @var{x} has not yet been assigned to a block, or it has not +been given an offset within that block. +@end table + +@node Flags +@section Flags in an RTL Expression +@cindex flags in RTL expression + +RTL expressions contain several flags (one-bit bit-fields) +that are used in certain types of expression. Most often they +are accessed with the following macros, which expand into lvalues. + +@table @code +@findex CONSTANT_POOL_ADDRESS_P +@cindex @code{symbol_ref} and @samp{/u} +@cindex @code{unchanging}, in @code{symbol_ref} +@item CONSTANT_POOL_ADDRESS_P (@var{x}) +Nonzero in a @code{symbol_ref} if it refers to part of the current +function's constant pool. For most targets these addresses are in a +@code{.rodata} section entirely separate from the function, but for +some targets the addresses are close to the beginning of the function. +In either case GCC assumes these addresses can be addressed directly, +perhaps with the help of base registers. +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex CONST_OR_PURE_CALL_P +@cindex @code{call_insn} and @samp{/u} +@cindex @code{unchanging}, in @code{call_insn} +@item CONST_OR_PURE_CALL_P (@var{x}) +In a @code{call_insn}, @code{note}, or an @code{expr_list} for notes, +indicates that the insn represents a call to a const or pure function. +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex INSN_ANNULLED_BRANCH_P +@cindex @code{jump_insn} and @samp{/u} +@cindex @code{call_insn} and @samp{/u} +@cindex @code{insn} and @samp{/u} +@cindex @code{unchanging}, in @code{jump_insn}, @code{call_insn} and @code{insn} +@item INSN_ANNULLED_BRANCH_P (@var{x}) +In a @code{jump_insn}, @code{call_insn}, or @code{insn} indicates +that the branch is an annulling one. See the discussion under +@code{sequence} below. Stored in the @code{unchanging} field and +printed as @samp{/u}. + +@findex INSN_DELETED_P +@cindex @code{insn} and @samp{/v} +@cindex @code{call_insn} and @samp{/v} +@cindex @code{jump_insn} and @samp{/v} +@cindex @code{code_label} and @samp{/v} +@cindex @code{barrier} and @samp{/v} +@cindex @code{note} and @samp{/v} +@cindex @code{volatil}, in @code{insn}, @code{call_insn}, @code{jump_insn}, @code{code_label}, @code{barrier}, and @code{note} +@item INSN_DELETED_P (@var{x}) +In an @code{insn}, @code{call_insn}, @code{jump_insn}, @code{code_label}, +@code{barrier}, or @code{note}, +nonzero if the insn has been deleted. Stored in the +@code{volatil} field and printed as @samp{/v}. + +@findex INSN_FROM_TARGET_P +@cindex @code{insn} and @samp{/s} +@cindex @code{jump_insn} and @samp{/s} +@cindex @code{call_insn} and @samp{/s} +@cindex @code{in_struct}, in @code{insn} and @code{jump_insn} and @code{call_insn} +@item INSN_FROM_TARGET_P (@var{x}) +In an @code{insn} or @code{jump_insn} or @code{call_insn} in a delay +slot of a branch, indicates that the insn +is from the target of the branch. If the branch insn has +@code{INSN_ANNULLED_BRANCH_P} set, this insn will only be executed if +the branch is taken. For annulled branches with +@code{INSN_FROM_TARGET_P} clear, the insn will be executed only if the +branch is not taken. When @code{INSN_ANNULLED_BRANCH_P} is not set, +this insn will always be executed. Stored in the @code{in_struct} +field and printed as @samp{/s}. + +@findex LABEL_PRESERVE_P +@cindex @code{code_label} and @samp{/i} +@cindex @code{note} and @samp{/i} +@cindex @code{in_struct}, in @code{code_label} and @code{note} +@item LABEL_PRESERVE_P (@var{x}) +In a @code{code_label} or @code{note}, indicates that the label is referenced by +code or data not visible to the RTL of a given function. +Labels referenced by a non-local goto will have this bit set. Stored +in the @code{in_struct} field and printed as @samp{/s}. + +@findex LABEL_REF_NONLOCAL_P +@cindex @code{label_ref} and @samp{/v} +@cindex @code{reg_label} and @samp{/v} +@cindex @code{volatil}, in @code{label_ref} and @code{reg_label} +@item LABEL_REF_NONLOCAL_P (@var{x}) +In @code{label_ref} and @code{reg_label} expressions, nonzero if this is +a reference to a non-local label. +Stored in the @code{volatil} field and printed as @samp{/v}. + +@findex MEM_IN_STRUCT_P +@cindex @code{mem} and @samp{/s} +@cindex @code{in_struct}, in @code{mem} +@item MEM_IN_STRUCT_P (@var{x}) +In @code{mem} expressions, nonzero for reference to an entire structure, +union or array, or to a component of one. Zero for references to a +scalar variable or through a pointer to a scalar. If both this flag and +@code{MEM_SCALAR_P} are clear, then we don't know whether this @code{mem} +is in a structure or not. Both flags should never be simultaneously set. +Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex MEM_KEEP_ALIAS_SET_P +@cindex @code{mem} and @samp{/j} +@cindex @code{jump}, in @code{mem} +@item MEM_KEEP_ALIAS_SET_P (@var{x}) +In @code{mem} expressions, 1 if we should keep the alias set for this +mem unchanged when we access a component. Set to 1, for example, when we +are already in a non-addressable component of an aggregate. +Stored in the @code{jump} field and printed as @samp{/j}. + +@findex MEM_SCALAR_P +@cindex @code{mem} and @samp{/f} +@cindex @code{frame_related}, in @code{mem} +@item MEM_SCALAR_P (@var{x}) +In @code{mem} expressions, nonzero for reference to a scalar known not +to be a member of a structure, union, or array. Zero for such +references and for indirections through pointers, even pointers pointing +to scalar types. If both this flag and @code{MEM_IN_STRUCT_P} are clear, +then we don't know whether this @code{mem} is in a structure or not. +Both flags should never be simultaneously set. +Stored in the @code{frame_related} field and printed as @samp{/f}. + +@findex MEM_VOLATILE_P +@cindex @code{mem} and @samp{/v} +@cindex @code{asm_input} and @samp{/v} +@cindex @code{asm_operands} and @samp{/v} +@cindex @code{volatil}, in @code{mem}, @code{asm_operands}, and @code{asm_input} +@item MEM_VOLATILE_P (@var{x}) +In @code{mem}, @code{asm_operands}, and @code{asm_input} expressions, +nonzero for volatile memory references. +Stored in the @code{volatil} field and printed as @samp{/v}. + +@findex MEM_NOTRAP_P +@cindex @code{mem} and @samp{/c} +@cindex @code{call}, in @code{mem} +@item MEM_NOTRAP_P (@var{x}) +In @code{mem}, nonzero for memory references that will not trap. +Stored in the @code{call} field and printed as @samp{/c}. + +@findex REG_FUNCTION_VALUE_P +@cindex @code{reg} and @samp{/i} +@cindex @code{integrated}, in @code{reg} +@item REG_FUNCTION_VALUE_P (@var{x}) +Nonzero in a @code{reg} if it is the place in which this function's +value is going to be returned. (This happens only in a hard +register.) Stored in the @code{integrated} field and printed as +@samp{/i}. + +@findex REG_POINTER +@cindex @code{reg} and @samp{/f} +@cindex @code{frame_related}, in @code{reg} +@item REG_POINTER (@var{x}) +Nonzero in a @code{reg} if the register holds a pointer. Stored in the +@code{frame_related} field and printed as @samp{/f}. + +@findex REG_USERVAR_P +@cindex @code{reg} and @samp{/v} +@cindex @code{volatil}, in @code{reg} +@item REG_USERVAR_P (@var{x}) +In a @code{reg}, nonzero if it corresponds to a variable present in +the user's source code. Zero for temporaries generated internally by +the compiler. Stored in the @code{volatil} field and printed as +@samp{/v}. + +The same hard register may be used also for collecting the values of +functions called by this one, but @code{REG_FUNCTION_VALUE_P} is zero +in this kind of use. + +@findex RTX_FRAME_RELATED_P +@cindex @code{insn} and @samp{/f} +@cindex @code{call_insn} and @samp{/f} +@cindex @code{jump_insn} and @samp{/f} +@cindex @code{barrier} and @samp{/f} +@cindex @code{set} and @samp{/f} +@cindex @code{frame_related}, in @code{insn}, @code{call_insn}, @code{jump_insn}, @code{barrier}, and @code{set} +@item RTX_FRAME_RELATED_P (@var{x}) +Nonzero in an @code{insn}, @code{call_insn}, @code{jump_insn}, +@code{barrier}, or @code{set} which is part of a function prologue +and sets the stack pointer, sets the frame pointer, or saves a register. +This flag should also be set on an instruction that sets up a temporary +register to use in place of the frame pointer. +Stored in the @code{frame_related} field and printed as @samp{/f}. + +In particular, on RISC targets where there are limits on the sizes of +immediate constants, it is sometimes impossible to reach the register +save area directly from the stack pointer. In that case, a temporary +register is used that is near enough to the register save area, and the +Canonical Frame Address, i.e., DWARF2's logical frame pointer, register +must (temporarily) be changed to be this temporary register. So, the +instruction that sets this temporary register must be marked as +@code{RTX_FRAME_RELATED_P}. + +If the marked instruction is overly complex (defined in terms of what +@code{dwarf2out_frame_debug_expr} can handle), you will also have to +create a @code{REG_FRAME_RELATED_EXPR} note and attach it to the +instruction. This note should contain a simple expression of the +computation performed by this instruction, i.e., one that +@code{dwarf2out_frame_debug_expr} can handle. + +This flag is required for exception handling support on targets with RTL +prologues. + +@cindex @code{insn} and @samp{/i} +@cindex @code{call_insn} and @samp{/i} +@cindex @code{jump_insn} and @samp{/i} +@cindex @code{barrier} and @samp{/i} +@cindex @code{code_label} and @samp{/i} +@cindex @code{insn_list} and @samp{/i} +@cindex @code{const} and @samp{/i} +@cindex @code{note} and @samp{/i} +@cindex @code{integrated}, in @code{insn}, @code{call_insn}, @code{jump_insn}, @code{barrier}, @code{code_label}, @code{insn_list}, @code{const}, and @code{note} +@code{code_label}, @code{insn_list}, @code{const}, or @code{note} if it +resulted from an in-line function call. +Stored in the @code{integrated} field and printed as @samp{/i}. + +@findex MEM_READONLY_P +@cindex @code{mem} and @samp{/u} +@cindex @code{unchanging}, in @code{mem} +@item MEM_READONLY_P (@var{x}) +Nonzero in a @code{mem}, if the memory is statically allocated and read-only. + +Read-only in this context means never modified during the lifetime of the +program, not necessarily in ROM or in write-disabled pages. A common +example of the later is a shared library's global offset table. This +table is initialized by the runtime loader, so the memory is technically +writable, but after control is transfered from the runtime loader to the +application, this memory will never be subsequently modified. + +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex SCHED_GROUP_P +@cindex @code{insn} and @samp{/s} +@cindex @code{call_insn} and @samp{/s} +@cindex @code{jump_insn} and @samp{/s} +@cindex @code{in_struct}, in @code{insn}, @code{jump_insn} and @code{call_insn} +@item SCHED_GROUP_P (@var{x}) +During instruction scheduling, in an @code{insn}, @code{call_insn} or +@code{jump_insn}, indicates that the +previous insn must be scheduled together with this insn. This is used to +ensure that certain groups of instructions will not be split up by the +instruction scheduling pass, for example, @code{use} insns before +a @code{call_insn} may not be separated from the @code{call_insn}. +Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex SET_IS_RETURN_P +@cindex @code{insn} and @samp{/j} +@cindex @code{jump}, in @code{insn} +@item SET_IS_RETURN_P (@var{x}) +For a @code{set}, nonzero if it is for a return. +Stored in the @code{jump} field and printed as @samp{/j}. + +@findex SIBLING_CALL_P +@cindex @code{call_insn} and @samp{/j} +@cindex @code{jump}, in @code{call_insn} +@item SIBLING_CALL_P (@var{x}) +For a @code{call_insn}, nonzero if the insn is a sibling call. +Stored in the @code{jump} field and printed as @samp{/j}. + +@findex STRING_POOL_ADDRESS_P +@cindex @code{symbol_ref} and @samp{/f} +@cindex @code{frame_related}, in @code{symbol_ref} +@item STRING_POOL_ADDRESS_P (@var{x}) +For a @code{symbol_ref} expression, nonzero if it addresses this function's +string constant pool. +Stored in the @code{frame_related} field and printed as @samp{/f}. + +@findex SUBREG_PROMOTED_UNSIGNED_P +@cindex @code{subreg} and @samp{/u} and @samp{/v} +@cindex @code{unchanging}, in @code{subreg} +@cindex @code{volatil}, in @code{subreg} +@item SUBREG_PROMOTED_UNSIGNED_P (@var{x}) +Returns a value greater then zero for a @code{subreg} that has +@code{SUBREG_PROMOTED_VAR_P} nonzero if the object being referenced is kept +zero-extended, zero if it is kept sign-extended, and less then zero if it is +extended some other way via the @code{ptr_extend} instruction. +Stored in the @code{unchanging} +field and @code{volatil} field, printed as @samp{/u} and @samp{/v}. +This macro may only be used to get the value it may not be used to change +the value. Use @code{SUBREG_PROMOTED_UNSIGNED_SET} to change the value. + +@findex SUBREG_PROMOTED_UNSIGNED_SET +@cindex @code{subreg} and @samp{/u} +@cindex @code{unchanging}, in @code{subreg} +@cindex @code{volatil}, in @code{subreg} +@item SUBREG_PROMOTED_UNSIGNED_SET (@var{x}) +Set the @code{unchanging} and @code{volatil} fields in a @code{subreg} +to reflect zero, sign, or other extension. If @code{volatil} is +zero, then @code{unchanging} as nonzero means zero extension and as +zero means sign extension. If @code{volatil} is nonzero then some +other type of extension was done via the @code{ptr_extend} instruction. + +@findex SUBREG_PROMOTED_VAR_P +@cindex @code{subreg} and @samp{/s} +@cindex @code{in_struct}, in @code{subreg} +@item SUBREG_PROMOTED_VAR_P (@var{x}) +Nonzero in a @code{subreg} if it was made when accessing an object that +was promoted to a wider mode in accord with the @code{PROMOTED_MODE} machine +description macro (@pxref{Storage Layout}). In this case, the mode of +the @code{subreg} is the declared mode of the object and the mode of +@code{SUBREG_REG} is the mode of the register that holds the object. +Promoted variables are always either sign- or zero-extended to the wider +mode on every assignment. Stored in the @code{in_struct} field and +printed as @samp{/s}. + +@findex SYMBOL_REF_USED +@cindex @code{used}, in @code{symbol_ref} +@item SYMBOL_REF_USED (@var{x}) +In a @code{symbol_ref}, indicates that @var{x} has been used. This is +normally only used to ensure that @var{x} is only declared external +once. Stored in the @code{used} field. + +@findex SYMBOL_REF_WEAK +@cindex @code{symbol_ref} and @samp{/i} +@cindex @code{integrated}, in @code{symbol_ref} +@item SYMBOL_REF_WEAK (@var{x}) +In a @code{symbol_ref}, indicates that @var{x} has been declared weak. +Stored in the @code{integrated} field and printed as @samp{/i}. + +@findex SYMBOL_REF_FLAG +@cindex @code{symbol_ref} and @samp{/v} +@cindex @code{volatil}, in @code{symbol_ref} +@item SYMBOL_REF_FLAG (@var{x}) +In a @code{symbol_ref}, this is used as a flag for machine-specific purposes. +Stored in the @code{volatil} field and printed as @samp{/v}. + +Most uses of @code{SYMBOL_REF_FLAG} are historic and may be subsumed +by @code{SYMBOL_REF_FLAGS}. Certainly use of @code{SYMBOL_REF_FLAGS} +is mandatory if the target requires more than one bit of storage. +@end table + +These are the fields to which the above macros refer: + +@table @code +@findex call +@cindex @samp{/c} in RTL dump +@item call +In a @code{mem}, 1 means that the memory reference will not trap. + +In an RTL dump, this flag is represented as @samp{/c}. + +@findex frame_related +@cindex @samp{/f} in RTL dump +@item frame_related +In an @code{insn} or @code{set} expression, 1 means that it is part of +a function prologue and sets the stack pointer, sets the frame pointer, +saves a register, or sets up a temporary register to use in place of the +frame pointer. + +In @code{reg} expressions, 1 means that the register holds a pointer. + +In @code{symbol_ref} expressions, 1 means that the reference addresses +this function's string constant pool. + +In @code{mem} expressions, 1 means that the reference is to a scalar. + +In an RTL dump, this flag is represented as @samp{/f}. + +@findex in_struct +@cindex @samp{/s} in RTL dump +@item in_struct +In @code{mem} expressions, it is 1 if the memory datum referred to is +all or part of a structure or array; 0 if it is (or might be) a scalar +variable. A reference through a C pointer has 0 because the pointer +might point to a scalar variable. This information allows the compiler +to determine something about possible cases of aliasing. + +In @code{reg} expressions, it is 1 if the register has its entire life +contained within the test expression of some loop. + +In @code{subreg} expressions, 1 means that the @code{subreg} is accessing +an object that has had its mode promoted from a wider mode. + +In @code{label_ref} expressions, 1 means that the referenced label is +outside the innermost loop containing the insn in which the @code{label_ref} +was found. + +In @code{code_label} expressions, it is 1 if the label may never be deleted. +This is used for labels which are the target of non-local gotos. Such a +label that would have been deleted is replaced with a @code{note} of type +@code{NOTE_INSN_DELETED_LABEL}. + +In an @code{insn} during dead-code elimination, 1 means that the insn is +dead code. + +In an @code{insn} or @code{jump_insn} during reorg for an insn in the +delay slot of a branch, +1 means that this insn is from the target of the branch. + +In an @code{insn} during instruction scheduling, 1 means that this insn +must be scheduled as part of a group together with the previous insn. + +In an RTL dump, this flag is represented as @samp{/s}. + +@findex integrated +@cindex @samp{/i} in RTL dump +@item integrated +In an @code{insn}, @code{insn_list}, or @code{const}, 1 means the RTL was +produced by procedure integration. + +In @code{reg} expressions, 1 means the register contains +the value to be returned by the current function. On +machines that pass parameters in registers, the same register number +may be used for parameters as well, but this flag is not set on such +uses. + +In @code{symbol_ref} expressions, 1 means the referenced symbol is weak. + +In an RTL dump, this flag is represented as @samp{/i}. + +@findex jump +@cindex @samp{/j} in RTL dump +@item jump +In a @code{mem} expression, 1 means we should keep the alias set for this +mem unchanged when we access a component. + +In a @code{set}, 1 means it is for a return. + +In a @code{call_insn}, 1 means it is a sibling call. + +In an RTL dump, this flag is represented as @samp{/j}. + +@findex unchanging +@cindex @samp{/u} in RTL dump +@item unchanging +In @code{reg} and @code{mem} expressions, 1 means +that the value of the expression never changes. + +In @code{subreg} expressions, it is 1 if the @code{subreg} references an +unsigned object whose mode has been promoted to a wider mode. + +In an @code{insn} or @code{jump_insn} in the delay slot of a branch +instruction, 1 means an annulling branch should be used. + +In a @code{symbol_ref} expression, 1 means that this symbol addresses +something in the per-function constant pool. + +In a @code{call_insn}, @code{note}, or an @code{expr_list} of notes, +1 means that this instruction is a call to a const or pure function. + +In an RTL dump, this flag is represented as @samp{/u}. + +@findex used +@item used +This flag is used directly (without an access macro) at the end of RTL +generation for a function, to count the number of times an expression +appears in insns. Expressions that appear more than once are copied, +according to the rules for shared structure (@pxref{Sharing}). + +For a @code{reg}, it is used directly (without an access macro) by the +leaf register renumbering code to ensure that each register is only +renumbered once. + +In a @code{symbol_ref}, it indicates that an external declaration for +the symbol has already been written. + +@findex volatil +@cindex @samp{/v} in RTL dump +@item volatil +@cindex volatile memory references +In a @code{mem}, @code{asm_operands}, or @code{asm_input} +expression, it is 1 if the memory +reference is volatile. Volatile memory references may not be deleted, +reordered or combined. + +In a @code{symbol_ref} expression, it is used for machine-specific +purposes. + +In a @code{reg} expression, it is 1 if the value is a user-level variable. +0 indicates an internal compiler temporary. + +In an @code{insn}, 1 means the insn has been deleted. + +In @code{label_ref} and @code{reg_label} expressions, 1 means a reference +to a non-local label. + +In an RTL dump, this flag is represented as @samp{/v}. +@end table + +@node Machine Modes +@section Machine Modes +@cindex machine modes + +@findex enum machine_mode +A machine mode describes a size of data object and the representation used +for it. In the C code, machine modes are represented by an enumeration +type, @code{enum machine_mode}, defined in @file{machmode.def}. Each RTL +expression has room for a machine mode and so do certain kinds of tree +expressions (declarations and types, to be precise). + +In debugging dumps and machine descriptions, the machine mode of an RTL +expression is written after the expression code with a colon to separate +them. The letters @samp{mode} which appear at the end of each machine mode +name are omitted. For example, @code{(reg:SI 38)} is a @code{reg} +expression with machine mode @code{SImode}. If the mode is +@code{VOIDmode}, it is not written at all. + +Here is a table of machine modes. The term ``byte'' below refers to an +object of @code{BITS_PER_UNIT} bits (@pxref{Storage Layout}). + +@table @code +@findex BImode +@item BImode +``Bit'' mode represents a single bit, for predicate registers. + +@findex QImode +@item QImode +``Quarter-Integer'' mode represents a single byte treated as an integer. + +@findex HImode +@item HImode +``Half-Integer'' mode represents a two-byte integer. + +@findex PSImode +@item PSImode +``Partial Single Integer'' mode represents an integer which occupies +four bytes but which doesn't really use all four. On some machines, +this is the right mode to use for pointers. + +@findex SImode +@item SImode +``Single Integer'' mode represents a four-byte integer. + +@findex PDImode +@item PDImode +``Partial Double Integer'' mode represents an integer which occupies +eight bytes but which doesn't really use all eight. On some machines, +this is the right mode to use for certain pointers. + +@findex DImode +@item DImode +``Double Integer'' mode represents an eight-byte integer. + +@findex TImode +@item TImode +``Tetra Integer'' (?) mode represents a sixteen-byte integer. + +@findex OImode +@item OImode +``Octa Integer'' (?) mode represents a thirty-two-byte integer. + +@findex QFmode +@item QFmode +``Quarter-Floating'' mode represents a quarter-precision (single byte) +floating point number. + +@findex HFmode +@item HFmode +``Half-Floating'' mode represents a half-precision (two byte) floating +point number. + +@findex TQFmode +@item TQFmode +``Three-Quarter-Floating'' (?) mode represents a three-quarter-precision +(three byte) floating point number. + +@findex SFmode +@item SFmode +``Single Floating'' mode represents a four byte floating point number. +In the common case, of a processor with IEEE arithmetic and 8-bit bytes, +this is a single-precision IEEE floating point number; it can also be +used for double-precision (on processors with 16-bit bytes) and +single-precision VAX and IBM types. + +@findex DFmode +@item DFmode +``Double Floating'' mode represents an eight byte floating point number. +In the common case, of a processor with IEEE arithmetic and 8-bit bytes, +this is a double-precision IEEE floating point number. + +@findex XFmode +@item XFmode +``Extended Floating'' mode represents an IEEE extended floating point +number. This mode only has 80 meaningful bits (ten bytes). Some +processors require such numbers to be padded to twelve bytes, others +to sixteen; this mode is used for either. + +@findex SDmode +@item SDmode +``Single Decimal Floating'' mode represents a four byte decimal +floating point number (as distinct from conventional binary floating +point). + +@findex DDmode +@item DDmode +``Double Decimal Floating'' mode represents an eight byte decimal +floating point number. + +@findex TDmode +@item TDmode +``Tetra Decimal Floating'' mode represents a sixteen byte decimal +floating point number all 128 of whose bits are meaningful. + +@findex TFmode +@item TFmode +``Tetra Floating'' mode represents a sixteen byte floating point number +all 128 of whose bits are meaningful. One common use is the +IEEE quad-precision format. + +@findex CCmode +@item CCmode +``Condition Code'' mode represents the value of a condition code, which +is a machine-specific set of bits used to represent the result of a +comparison operation. Other machine-specific modes may also be used for +the condition code. These modes are not used on machines that use +@code{cc0} (see @pxref{Condition Code}). + +@findex BLKmode +@item BLKmode +``Block'' mode represents values that are aggregates to which none of +the other modes apply. In RTL, only memory references can have this mode, +and only if they appear in string-move or vector instructions. On machines +which have no such instructions, @code{BLKmode} will not appear in RTL@. + +@findex VOIDmode +@item VOIDmode +Void mode means the absence of a mode or an unspecified mode. +For example, RTL expressions of code @code{const_int} have mode +@code{VOIDmode} because they can be taken to have whatever mode the context +requires. In debugging dumps of RTL, @code{VOIDmode} is expressed by +the absence of any mode. + +@findex QCmode +@findex HCmode +@findex SCmode +@findex DCmode +@findex XCmode +@findex TCmode +@item QCmode, HCmode, SCmode, DCmode, XCmode, TCmode +These modes stand for a complex number represented as a pair of floating +point values. The floating point values are in @code{QFmode}, +@code{HFmode}, @code{SFmode}, @code{DFmode}, @code{XFmode}, and +@code{TFmode}, respectively. + +@findex CQImode +@findex CHImode +@findex CSImode +@findex CDImode +@findex CTImode +@findex COImode +@item CQImode, CHImode, CSImode, CDImode, CTImode, COImode +These modes stand for a complex number represented as a pair of integer +values. The integer values are in @code{QImode}, @code{HImode}, +@code{SImode}, @code{DImode}, @code{TImode}, and @code{OImode}, +respectively. +@end table + +The machine description defines @code{Pmode} as a C macro which expands +into the machine mode used for addresses. Normally this is the mode +whose size is @code{BITS_PER_WORD}, @code{SImode} on 32-bit machines. + +The only modes which a machine description @i{must} support are +@code{QImode}, and the modes corresponding to @code{BITS_PER_WORD}, +@code{FLOAT_TYPE_SIZE} and @code{DOUBLE_TYPE_SIZE}. +The compiler will attempt to use @code{DImode} for 8-byte structures and +unions, but this can be prevented by overriding the definition of +@code{MAX_FIXED_MODE_SIZE}. Alternatively, you can have the compiler +use @code{TImode} for 16-byte structures and unions. Likewise, you can +arrange for the C type @code{short int} to avoid using @code{HImode}. + +@cindex mode classes +Very few explicit references to machine modes remain in the compiler and +these few references will soon be removed. Instead, the machine modes +are divided into mode classes. These are represented by the enumeration +type @code{enum mode_class} defined in @file{machmode.h}. The possible +mode classes are: + +@table @code +@findex MODE_INT +@item MODE_INT +Integer modes. By default these are @code{BImode}, @code{QImode}, +@code{HImode}, @code{SImode}, @code{DImode}, @code{TImode}, and +@code{OImode}. + +@findex MODE_PARTIAL_INT +@item MODE_PARTIAL_INT +The ``partial integer'' modes, @code{PQImode}, @code{PHImode}, +@code{PSImode} and @code{PDImode}. + +@findex MODE_FLOAT +@item MODE_FLOAT +Floating point modes. By default these are @code{QFmode}, +@code{HFmode}, @code{TQFmode}, @code{SFmode}, @code{DFmode}, +@code{XFmode} and @code{TFmode}. + +@findex MODE_DECIMAL_FLOAT +@item MODE_DECIMAL_FLOAT +Decimal floating point modes. By default these are @code{SDmode}, +@code{DDmode} and @code{TDmode}. + +@findex MODE_COMPLEX_INT +@item MODE_COMPLEX_INT +Complex integer modes. (These are not currently implemented). + +@findex MODE_COMPLEX_FLOAT +@item MODE_COMPLEX_FLOAT +Complex floating point modes. By default these are @code{QCmode}, +@code{HCmode}, @code{SCmode}, @code{DCmode}, @code{XCmode}, and +@code{TCmode}. + +@findex MODE_FUNCTION +@item MODE_FUNCTION +Algol or Pascal function variables including a static chain. +(These are not currently implemented). + +@findex MODE_CC +@item MODE_CC +Modes representing condition code values. These are @code{CCmode} plus +any @code{CC_MODE} modes listed in the @file{@var{machine}-modes.def}. +@xref{Jump Patterns}, +also see @ref{Condition Code}. + +@findex MODE_RANDOM +@item MODE_RANDOM +This is a catchall mode class for modes which don't fit into the above +classes. Currently @code{VOIDmode} and @code{BLKmode} are in +@code{MODE_RANDOM}. +@end table + +Here are some C macros that relate to machine modes: + +@table @code +@findex GET_MODE +@item GET_MODE (@var{x}) +Returns the machine mode of the RTX @var{x}. + +@findex PUT_MODE +@item PUT_MODE (@var{x}, @var{newmode}) +Alters the machine mode of the RTX @var{x} to be @var{newmode}. + +@findex NUM_MACHINE_MODES +@item NUM_MACHINE_MODES +Stands for the number of machine modes available on the target +machine. This is one greater than the largest numeric value of any +machine mode. + +@findex GET_MODE_NAME +@item GET_MODE_NAME (@var{m}) +Returns the name of mode @var{m} as a string. + +@findex GET_MODE_CLASS +@item GET_MODE_CLASS (@var{m}) +Returns the mode class of mode @var{m}. + +@findex GET_MODE_WIDER_MODE +@item GET_MODE_WIDER_MODE (@var{m}) +Returns the next wider natural mode. For example, the expression +@code{GET_MODE_WIDER_MODE (QImode)} returns @code{HImode}. + +@findex GET_MODE_SIZE +@item GET_MODE_SIZE (@var{m}) +Returns the size in bytes of a datum of mode @var{m}. + +@findex GET_MODE_BITSIZE +@item GET_MODE_BITSIZE (@var{m}) +Returns the size in bits of a datum of mode @var{m}. + +@findex GET_MODE_MASK +@item GET_MODE_MASK (@var{m}) +Returns a bitmask containing 1 for all bits in a word that fit within +mode @var{m}. This macro can only be used for modes whose bitsize is +less than or equal to @code{HOST_BITS_PER_INT}. + +@findex GET_MODE_ALIGNMENT +@item GET_MODE_ALIGNMENT (@var{m}) +Return the required alignment, in bits, for an object of mode @var{m}. + +@findex GET_MODE_UNIT_SIZE +@item GET_MODE_UNIT_SIZE (@var{m}) +Returns the size in bytes of the subunits of a datum of mode @var{m}. +This is the same as @code{GET_MODE_SIZE} except in the case of complex +modes. For them, the unit size is the size of the real or imaginary +part. + +@findex GET_MODE_NUNITS +@item GET_MODE_NUNITS (@var{m}) +Returns the number of units contained in a mode, i.e., +@code{GET_MODE_SIZE} divided by @code{GET_MODE_UNIT_SIZE}. + +@findex GET_CLASS_NARROWEST_MODE +@item GET_CLASS_NARROWEST_MODE (@var{c}) +Returns the narrowest mode in mode class @var{c}. +@end table + +@findex byte_mode +@findex word_mode +The global variables @code{byte_mode} and @code{word_mode} contain modes +whose classes are @code{MODE_INT} and whose bitsizes are either +@code{BITS_PER_UNIT} or @code{BITS_PER_WORD}, respectively. On 32-bit +machines, these are @code{QImode} and @code{SImode}, respectively. + +@node Constants +@section Constant Expression Types +@cindex RTL constants +@cindex RTL constant expression types + +The simplest RTL expressions are those that represent constant values. + +@table @code +@findex const_int +@item (const_int @var{i}) +This type of expression represents the integer value @var{i}. @var{i} +is customarily accessed with the macro @code{INTVAL} as in +@code{INTVAL (@var{exp})}, which is equivalent to @code{XWINT (@var{exp}, 0)}. + +Constants generated for modes with fewer bits than @code{HOST_WIDE_INT} +must be sign extended to full width (e.g., with @code{gen_int_mode}). + +@findex const0_rtx +@findex const1_rtx +@findex const2_rtx +@findex constm1_rtx +There is only one expression object for the integer value zero; it is +the value of the variable @code{const0_rtx}. Likewise, the only +expression for integer value one is found in @code{const1_rtx}, the only +expression for integer value two is found in @code{const2_rtx}, and the +only expression for integer value negative one is found in +@code{constm1_rtx}. Any attempt to create an expression of code +@code{const_int} and value zero, one, two or negative one will return +@code{const0_rtx}, @code{const1_rtx}, @code{const2_rtx} or +@code{constm1_rtx} as appropriate. + +@findex const_true_rtx +Similarly, there is only one object for the integer whose value is +@code{STORE_FLAG_VALUE}. It is found in @code{const_true_rtx}. If +@code{STORE_FLAG_VALUE} is one, @code{const_true_rtx} and +@code{const1_rtx} will point to the same object. If +@code{STORE_FLAG_VALUE} is @minus{}1, @code{const_true_rtx} and +@code{constm1_rtx} will point to the same object. + +@findex const_double +@item (const_double:@var{m} @var{addr} @var{i0} @var{i1} @dots{}) +Represents either a floating-point constant of mode @var{m} or an +integer constant too large to fit into @code{HOST_BITS_PER_WIDE_INT} +bits but small enough to fit within twice that number of bits (GCC +does not provide a mechanism to represent even larger constants). In +the latter case, @var{m} will be @code{VOIDmode}. + +@findex const_vector +@item (const_vector:@var{m} [@var{x0} @var{x1} @dots{}]) +Represents a vector constant. The square brackets stand for the vector +containing the constant elements. @var{x0}, @var{x1} and so on are +the @code{const_int} or @code{const_double} elements. + +The number of units in a @code{const_vector} is obtained with the macro +@code{CONST_VECTOR_NUNITS} as in @code{CONST_VECTOR_NUNITS (@var{v})}. + +Individual elements in a vector constant are accessed with the macro +@code{CONST_VECTOR_ELT} as in @code{CONST_VECTOR_ELT (@var{v}, @var{n})} +where @var{v} is the vector constant and @var{n} is the element +desired. + +@findex CONST_DOUBLE_MEM +@findex CONST_DOUBLE_CHAIN +@var{addr} is used to contain the @code{mem} expression that corresponds +to the location in memory that at which the constant can be found. If +it has not been allocated a memory location, but is on the chain of all +@code{const_double} expressions in this compilation (maintained using an +undisplayed field), @var{addr} contains @code{const0_rtx}. If it is not +on the chain, @var{addr} contains @code{cc0_rtx}. @var{addr} is +customarily accessed with the macro @code{CONST_DOUBLE_MEM} and the +chain field via @code{CONST_DOUBLE_CHAIN}. + +@findex CONST_DOUBLE_LOW +If @var{m} is @code{VOIDmode}, the bits of the value are stored in +@var{i0} and @var{i1}. @var{i0} is customarily accessed with the macro +@code{CONST_DOUBLE_LOW} and @var{i1} with @code{CONST_DOUBLE_HIGH}. + +If the constant is floating point (regardless of its precision), then +the number of integers used to store the value depends on the size of +@code{REAL_VALUE_TYPE} (@pxref{Floating Point}). The integers +represent a floating point number, but not precisely in the target +machine's or host machine's floating point format. To convert them to +the precise bit pattern used by the target machine, use the macro +@code{REAL_VALUE_TO_TARGET_DOUBLE} and friends (@pxref{Data Output}). + +@findex CONST0_RTX +@findex CONST1_RTX +@findex CONST2_RTX +The macro @code{CONST0_RTX (@var{mode})} refers to an expression with +value 0 in mode @var{mode}. If mode @var{mode} is of mode class +@code{MODE_INT}, it returns @code{const0_rtx}. If mode @var{mode} is of +mode class @code{MODE_FLOAT}, it returns a @code{CONST_DOUBLE} +expression in mode @var{mode}. Otherwise, it returns a +@code{CONST_VECTOR} expression in mode @var{mode}. Similarly, the macro +@code{CONST1_RTX (@var{mode})} refers to an expression with value 1 in +mode @var{mode} and similarly for @code{CONST2_RTX}. The +@code{CONST1_RTX} and @code{CONST2_RTX} macros are undefined +for vector modes. + +@findex const_string +@item (const_string @var{str}) +Represents a constant string with value @var{str}. Currently this is +used only for insn attributes (@pxref{Insn Attributes}) since constant +strings in C are placed in memory. + +@findex symbol_ref +@item (symbol_ref:@var{mode} @var{symbol}) +Represents the value of an assembler label for data. @var{symbol} is +a string that describes the name of the assembler label. If it starts +with a @samp{*}, the label is the rest of @var{symbol} not including +the @samp{*}. Otherwise, the label is @var{symbol}, usually prefixed +with @samp{_}. + +The @code{symbol_ref} contains a mode, which is usually @code{Pmode}. +Usually that is the only mode for which a symbol is directly valid. + +@findex label_ref +@item (label_ref:@var{mode} @var{label}) +Represents the value of an assembler label for code. It contains one +operand, an expression, which must be a @code{code_label} or a @code{note} +of type @code{NOTE_INSN_DELETED_LABEL} that appears in the instruction +sequence to identify the place where the label should go. + +The reason for using a distinct expression type for code label +references is so that jump optimization can distinguish them. + +The @code{label_ref} contains a mode, which is usually @code{Pmode}. +Usually that is the only mode for which a label is directly valid. + +@item (const:@var{m} @var{exp}) +Represents a constant that is the result of an assembly-time +arithmetic computation. The operand, @var{exp}, is an expression that +contains only constants (@code{const_int}, @code{symbol_ref} and +@code{label_ref} expressions) combined with @code{plus} and +@code{minus}. However, not all combinations are valid, since the +assembler cannot do arbitrary arithmetic on relocatable symbols. + +@var{m} should be @code{Pmode}. + +@findex high +@item (high:@var{m} @var{exp}) +Represents the high-order bits of @var{exp}, usually a +@code{symbol_ref}. The number of bits is machine-dependent and is +normally the number of bits specified in an instruction that initializes +the high order bits of a register. It is used with @code{lo_sum} to +represent the typical two-instruction sequence used in RISC machines to +reference a global memory location. + +@var{m} should be @code{Pmode}. +@end table + +@node Regs and Memory +@section Registers and Memory +@cindex RTL register expressions +@cindex RTL memory expressions + +Here are the RTL expression types for describing access to machine +registers and to main memory. + +@table @code +@findex reg +@cindex hard registers +@cindex pseudo registers +@item (reg:@var{m} @var{n}) +For small values of the integer @var{n} (those that are less than +@code{FIRST_PSEUDO_REGISTER}), this stands for a reference to machine +register number @var{n}: a @dfn{hard register}. For larger values of +@var{n}, it stands for a temporary value or @dfn{pseudo register}. +The compiler's strategy is to generate code assuming an unlimited +number of such pseudo registers, and later convert them into hard +registers or into memory references. + +@var{m} is the machine mode of the reference. It is necessary because +machines can generally refer to each register in more than one mode. +For example, a register may contain a full word but there may be +instructions to refer to it as a half word or as a single byte, as +well as instructions to refer to it as a floating point number of +various precisions. + +Even for a register that the machine can access in only one mode, +the mode must always be specified. + +The symbol @code{FIRST_PSEUDO_REGISTER} is defined by the machine +description, since the number of hard registers on the machine is an +invariant characteristic of the machine. Note, however, that not +all of the machine registers must be general registers. All the +machine registers that can be used for storage of data are given +hard register numbers, even those that can be used only in certain +instructions or can hold only certain types of data. + +A hard register may be accessed in various modes throughout one +function, but each pseudo register is given a natural mode +and is accessed only in that mode. When it is necessary to describe +an access to a pseudo register using a nonnatural mode, a @code{subreg} +expression is used. + +A @code{reg} expression with a machine mode that specifies more than +one word of data may actually stand for several consecutive registers. +If in addition the register number specifies a hardware register, then +it actually represents several consecutive hardware registers starting +with the specified one. + +Each pseudo register number used in a function's RTL code is +represented by a unique @code{reg} expression. + +@findex FIRST_VIRTUAL_REGISTER +@findex LAST_VIRTUAL_REGISTER +Some pseudo register numbers, those within the range of +@code{FIRST_VIRTUAL_REGISTER} to @code{LAST_VIRTUAL_REGISTER} only +appear during the RTL generation phase and are eliminated before the +optimization phases. These represent locations in the stack frame that +cannot be determined until RTL generation for the function has been +completed. The following virtual register numbers are defined: + +@table @code +@findex VIRTUAL_INCOMING_ARGS_REGNUM +@item VIRTUAL_INCOMING_ARGS_REGNUM +This points to the first word of the incoming arguments passed on the +stack. Normally these arguments are placed there by the caller, but the +callee may have pushed some arguments that were previously passed in +registers. + +@cindex @code{FIRST_PARM_OFFSET} and virtual registers +@cindex @code{ARG_POINTER_REGNUM} and virtual registers +When RTL generation is complete, this virtual register is replaced +by the sum of the register given by @code{ARG_POINTER_REGNUM} and the +value of @code{FIRST_PARM_OFFSET}. + +@findex VIRTUAL_STACK_VARS_REGNUM +@cindex @code{FRAME_GROWS_DOWNWARD} and virtual registers +@item VIRTUAL_STACK_VARS_REGNUM +If @code{FRAME_GROWS_DOWNWARD} is defined to a nonzero value, this points +to immediately above the first variable on the stack. Otherwise, it points +to the first variable on the stack. + +@cindex @code{STARTING_FRAME_OFFSET} and virtual registers +@cindex @code{FRAME_POINTER_REGNUM} and virtual registers +@code{VIRTUAL_STACK_VARS_REGNUM} is replaced with the sum of the +register given by @code{FRAME_POINTER_REGNUM} and the value +@code{STARTING_FRAME_OFFSET}. + +@findex VIRTUAL_STACK_DYNAMIC_REGNUM +@item VIRTUAL_STACK_DYNAMIC_REGNUM +This points to the location of dynamically allocated memory on the stack +immediately after the stack pointer has been adjusted by the amount of +memory desired. + +@cindex @code{STACK_DYNAMIC_OFFSET} and virtual registers +@cindex @code{STACK_POINTER_REGNUM} and virtual registers +This virtual register is replaced by the sum of the register given by +@code{STACK_POINTER_REGNUM} and the value @code{STACK_DYNAMIC_OFFSET}. + +@findex VIRTUAL_OUTGOING_ARGS_REGNUM +@item VIRTUAL_OUTGOING_ARGS_REGNUM +This points to the location in the stack at which outgoing arguments +should be written when the stack is pre-pushed (arguments pushed using +push insns should always use @code{STACK_POINTER_REGNUM}). + +@cindex @code{STACK_POINTER_OFFSET} and virtual registers +This virtual register is replaced by the sum of the register given by +@code{STACK_POINTER_REGNUM} and the value @code{STACK_POINTER_OFFSET}. +@end table + +@findex subreg +@item (subreg:@var{m} @var{reg} @var{bytenum}) +@code{subreg} expressions are used to refer to a register in a machine +mode other than its natural one, or to refer to one register of +a multi-part @code{reg} that actually refers to several registers. + +Each pseudo-register has a natural mode. If it is necessary to +operate on it in a different mode---for example, to perform a fullword +move instruction on a pseudo-register that contains a single +byte---the pseudo-register must be enclosed in a @code{subreg}. In +such a case, @var{bytenum} is zero. + +Usually @var{m} is at least as narrow as the mode of @var{reg}, in which +case it is restricting consideration to only the bits of @var{reg} that +are in @var{m}. + +Sometimes @var{m} is wider than the mode of @var{reg}. These +@code{subreg} expressions are often called @dfn{paradoxical}. They are +used in cases where we want to refer to an object in a wider mode but do +not care what value the additional bits have. The reload pass ensures +that paradoxical references are only made to hard registers. + +The other use of @code{subreg} is to extract the individual registers of +a multi-register value. Machine modes such as @code{DImode} and +@code{TImode} can indicate values longer than a word, values which +usually require two or more consecutive registers. To access one of the +registers, use a @code{subreg} with mode @code{SImode} and a +@var{bytenum} offset that says which register. + +Storing in a non-paradoxical @code{subreg} has undefined results for +bits belonging to the same word as the @code{subreg}. This laxity makes +it easier to generate efficient code for such instructions. To +represent an instruction that preserves all the bits outside of those in +the @code{subreg}, use @code{strict_low_part} around the @code{subreg}. + +@cindex @code{WORDS_BIG_ENDIAN}, effect on @code{subreg} +The compilation parameter @code{WORDS_BIG_ENDIAN}, if set to 1, says +that byte number zero is part of the most significant word; otherwise, +it is part of the least significant word. + +@cindex @code{BYTES_BIG_ENDIAN}, effect on @code{subreg} +The compilation parameter @code{BYTES_BIG_ENDIAN}, if set to 1, says +that byte number zero is the most significant byte within a word; +otherwise, it is the least significant byte within a word. + +@cindex @code{FLOAT_WORDS_BIG_ENDIAN}, (lack of) effect on @code{subreg} +On a few targets, @code{FLOAT_WORDS_BIG_ENDIAN} disagrees with +@code{WORDS_BIG_ENDIAN}. +However, most parts of the compiler treat floating point values as if +they had the same endianness as integer values. This works because +they handle them solely as a collection of integer values, with no +particular numerical value. Only real.c and the runtime libraries +care about @code{FLOAT_WORDS_BIG_ENDIAN}. + +@cindex combiner pass +@cindex reload pass +@cindex @code{subreg}, special reload handling +Between the combiner pass and the reload pass, it is possible to have a +paradoxical @code{subreg} which contains a @code{mem} instead of a +@code{reg} as its first operand. After the reload pass, it is also +possible to have a non-paradoxical @code{subreg} which contains a +@code{mem}; this usually occurs when the @code{mem} is a stack slot +which replaced a pseudo register. + +Note that it is not valid to access a @code{DFmode} value in @code{SFmode} +using a @code{subreg}. On some machines the most significant part of a +@code{DFmode} value does not have the same format as a single-precision +floating value. + +It is also not valid to access a single word of a multi-word value in a +hard register when less registers can hold the value than would be +expected from its size. For example, some 32-bit machines have +floating-point registers that can hold an entire @code{DFmode} value. +If register 10 were such a register @code{(subreg:SI (reg:DF 10) 4)} +would be invalid because there is no way to convert that reference to +a single machine register. The reload pass prevents @code{subreg} +expressions such as these from being formed. + +@findex SUBREG_REG +@findex SUBREG_BYTE +The first operand of a @code{subreg} expression is customarily accessed +with the @code{SUBREG_REG} macro and the second operand is customarily +accessed with the @code{SUBREG_BYTE} macro. + +@findex scratch +@cindex scratch operands +@item (scratch:@var{m}) +This represents a scratch register that will be required for the +execution of a single instruction and not used subsequently. It is +converted into a @code{reg} by either the local register allocator or +the reload pass. + +@code{scratch} is usually present inside a @code{clobber} operation +(@pxref{Side Effects}). + +@findex cc0 +@cindex condition code register +@item (cc0) +This refers to the machine's condition code register. It has no +operands and may not have a machine mode. There are two ways to use it: + +@itemize @bullet +@item +To stand for a complete set of condition code flags. This is best on +most machines, where each comparison sets the entire series of flags. + +With this technique, @code{(cc0)} may be validly used in only two +contexts: as the destination of an assignment (in test and compare +instructions) and in comparison operators comparing against zero +(@code{const_int} with value zero; that is to say, @code{const0_rtx}). + +@item +To stand for a single flag that is the result of a single condition. +This is useful on machines that have only a single flag bit, and in +which comparison instructions must specify the condition to test. + +With this technique, @code{(cc0)} may be validly used in only two +contexts: as the destination of an assignment (in test and compare +instructions) where the source is a comparison operator, and as the +first operand of @code{if_then_else} (in a conditional branch). +@end itemize + +@findex cc0_rtx +There is only one expression object of code @code{cc0}; it is the +value of the variable @code{cc0_rtx}. Any attempt to create an +expression of code @code{cc0} will return @code{cc0_rtx}. + +Instructions can set the condition code implicitly. On many machines, +nearly all instructions set the condition code based on the value that +they compute or store. It is not necessary to record these actions +explicitly in the RTL because the machine description includes a +prescription for recognizing the instructions that do so (by means of +the macro @code{NOTICE_UPDATE_CC}). @xref{Condition Code}. Only +instructions whose sole purpose is to set the condition code, and +instructions that use the condition code, need mention @code{(cc0)}. + +On some machines, the condition code register is given a register number +and a @code{reg} is used instead of @code{(cc0)}. This is usually the +preferable approach if only a small subset of instructions modify the +condition code. Other machines store condition codes in general +registers; in such cases a pseudo register should be used. + +Some machines, such as the SPARC and RS/6000, have two sets of +arithmetic instructions, one that sets and one that does not set the +condition code. This is best handled by normally generating the +instruction that does not set the condition code, and making a pattern +that both performs the arithmetic and sets the condition code register +(which would not be @code{(cc0)} in this case). For examples, search +for @samp{addcc} and @samp{andcc} in @file{sparc.md}. + +@findex pc +@item (pc) +@cindex program counter +This represents the machine's program counter. It has no operands and +may not have a machine mode. @code{(pc)} may be validly used only in +certain specific contexts in jump instructions. + +@findex pc_rtx +There is only one expression object of code @code{pc}; it is the value +of the variable @code{pc_rtx}. Any attempt to create an expression of +code @code{pc} will return @code{pc_rtx}. + +All instructions that do not jump alter the program counter implicitly +by incrementing it, but there is no need to mention this in the RTL@. + +@findex mem +@item (mem:@var{m} @var{addr} @var{alias}) +This RTX represents a reference to main memory at an address +represented by the expression @var{addr}. @var{m} specifies how large +a unit of memory is accessed. @var{alias} specifies an alias set for the +reference. In general two items are in different alias sets if they cannot +reference the same memory address. + +The construct @code{(mem:BLK (scratch))} is considered to alias all +other memories. Thus it may be used as a memory barrier in epilogue +stack deallocation patterns. + +@findex addressof +@item (addressof:@var{m} @var{reg}) +This RTX represents a request for the address of register @var{reg}. Its mode +is always @code{Pmode}. If there are any @code{addressof} +expressions left in the function after CSE, @var{reg} is forced into the +stack and the @code{addressof} expression is replaced with a @code{plus} +expression for the address of its stack slot. +@end table + +@node Arithmetic +@section RTL Expressions for Arithmetic +@cindex arithmetic, in RTL +@cindex math, in RTL +@cindex RTL expressions for arithmetic + +Unless otherwise specified, all the operands of arithmetic expressions +must be valid for mode @var{m}. An operand is valid for mode @var{m} +if it has mode @var{m}, or if it is a @code{const_int} or +@code{const_double} and @var{m} is a mode of class @code{MODE_INT}. + +For commutative binary operations, constants should be placed in the +second operand. + +@table @code +@findex plus +@findex ss_plus +@findex us_plus +@cindex RTL sum +@cindex RTL addition +@cindex RTL addition with signed saturation +@cindex RTL addition with unsigned saturation +@item (plus:@var{m} @var{x} @var{y}) +@itemx (ss_plus:@var{m} @var{x} @var{y}) +@itemx (us_plus:@var{m} @var{x} @var{y}) + +These three expressions all represent the sum of the values +represented by @var{x} and @var{y} carried out in machine mode +@var{m}. They differ in their behavior on overflow of integer modes. +@code{plus} wraps round modulo the width of @var{m}; @code{ss_plus} +saturates at the maximum signed value representable in @var{m}; +@code{us_plus} saturates at the maximum unsigned value. + +@c ??? What happens on overflow of floating point modes? + +@findex lo_sum +@item (lo_sum:@var{m} @var{x} @var{y}) + +This expression represents the sum of @var{x} and the low-order bits +of @var{y}. It is used with @code{high} (@pxref{Constants}) to +represent the typical two-instruction sequence used in RISC machines +to reference a global memory location. + +The number of low order bits is machine-dependent but is +normally the number of bits in a @code{Pmode} item minus the number of +bits set by @code{high}. + +@var{m} should be @code{Pmode}. + +@findex minus +@findex ss_minus +@findex us_minus +@cindex RTL difference +@cindex RTL subtraction +@cindex RTL subtraction with signed saturation +@cindex RTL subtraction with unsigned saturation +@item (minus:@var{m} @var{x} @var{y}) +@itemx (ss_minus:@var{m} @var{x} @var{y}) +@itemx (us_minus:@var{m} @var{x} @var{y}) + +These three expressions represent the result of subtracting @var{y} +from @var{x}, carried out in mode @var{M}. Behavior on overflow is +the same as for the three variants of @code{plus} (see above). + +@findex compare +@cindex RTL comparison +@item (compare:@var{m} @var{x} @var{y}) +Represents the result of subtracting @var{y} from @var{x} for purposes +of comparison. The result is computed without overflow, as if with +infinite precision. + +Of course, machines can't really subtract with infinite precision. +However, they can pretend to do so when only the sign of the result will +be used, which is the case when the result is stored in the condition +code. And that is the @emph{only} way this kind of expression may +validly be used: as a value to be stored in the condition codes, either +@code{(cc0)} or a register. @xref{Comparisons}. + +The mode @var{m} is not related to the modes of @var{x} and @var{y}, but +instead is the mode of the condition code value. If @code{(cc0)} is +used, it is @code{VOIDmode}. Otherwise it is some mode in class +@code{MODE_CC}, often @code{CCmode}. @xref{Condition Code}. If @var{m} +is @code{VOIDmode} or @code{CCmode}, the operation returns sufficient +information (in an unspecified format) so that any comparison operator +can be applied to the result of the @code{COMPARE} operation. For other +modes in class @code{MODE_CC}, the operation only returns a subset of +this information. + +Normally, @var{x} and @var{y} must have the same mode. Otherwise, +@code{compare} is valid only if the mode of @var{x} is in class +@code{MODE_INT} and @var{y} is a @code{const_int} or +@code{const_double} with mode @code{VOIDmode}. The mode of @var{x} +determines what mode the comparison is to be done in; thus it must not +be @code{VOIDmode}. + +If one of the operands is a constant, it should be placed in the +second operand and the comparison code adjusted as appropriate. + +A @code{compare} specifying two @code{VOIDmode} constants is not valid +since there is no way to know in what mode the comparison is to be +performed; the comparison must either be folded during the compilation +or the first operand must be loaded into a register while its mode is +still known. + +@findex neg +@findex ss_neg +@cindex negation +@cindex negation with signed saturation +@item (neg:@var{m} @var{x}) +@itemx (ss_neg:@var{m} @var{x}) +These two expressions represent the negation (subtraction from zero) of +the value represented by @var{x}, carried out in mode @var{m}. They +differ in the behavior on overflow of integer modes. In the case of +@code{neg}, the negation of the operand may be a number not representable +in mode @var{m}, in which case it is truncated to @var{m}. @code{ss_neg} +ensures that an out-of-bounds result saturates to the maximum or minimum +representable value. + +@findex mult +@cindex multiplication +@cindex product +@item (mult:@var{m} @var{x} @var{y}) +Represents the signed product of the values represented by @var{x} and +@var{y} carried out in machine mode @var{m}. + +Some machines support a multiplication that generates a product wider +than the operands. Write the pattern for this as + +@smallexample +(mult:@var{m} (sign_extend:@var{m} @var{x}) (sign_extend:@var{m} @var{y})) +@end smallexample + +where @var{m} is wider than the modes of @var{x} and @var{y}, which need +not be the same. + +For unsigned widening multiplication, use the same idiom, but with +@code{zero_extend} instead of @code{sign_extend}. + +@findex div +@cindex division +@cindex signed division +@cindex quotient +@item (div:@var{m} @var{x} @var{y}) +Represents the quotient in signed division of @var{x} by @var{y}, +carried out in machine mode @var{m}. If @var{m} is a floating point +mode, it represents the exact quotient; otherwise, the integerized +quotient. + +Some machines have division instructions in which the operands and +quotient widths are not all the same; you should represent +such instructions using @code{truncate} and @code{sign_extend} as in, + +@smallexample +(truncate:@var{m1} (div:@var{m2} @var{x} (sign_extend:@var{m2} @var{y}))) +@end smallexample + +@findex udiv +@cindex unsigned division +@cindex division +@item (udiv:@var{m} @var{x} @var{y}) +Like @code{div} but represents unsigned division. + +@findex mod +@findex umod +@cindex remainder +@cindex division +@item (mod:@var{m} @var{x} @var{y}) +@itemx (umod:@var{m} @var{x} @var{y}) +Like @code{div} and @code{udiv} but represent the remainder instead of +the quotient. + +@findex smin +@findex smax +@cindex signed minimum +@cindex signed maximum +@item (smin:@var{m} @var{x} @var{y}) +@itemx (smax:@var{m} @var{x} @var{y}) +Represents the smaller (for @code{smin}) or larger (for @code{smax}) of +@var{x} and @var{y}, interpreted as signed values in mode @var{m}. +When used with floating point, if both operands are zeros, or if either +operand is @code{NaN}, then it is unspecified which of the two operands +is returned as the result. + +@findex umin +@findex umax +@cindex unsigned minimum and maximum +@item (umin:@var{m} @var{x} @var{y}) +@itemx (umax:@var{m} @var{x} @var{y}) +Like @code{smin} and @code{smax}, but the values are interpreted as unsigned +integers. + +@findex not +@cindex complement, bitwise +@cindex bitwise complement +@item (not:@var{m} @var{x}) +Represents the bitwise complement of the value represented by @var{x}, +carried out in mode @var{m}, which must be a fixed-point machine mode. + +@findex and +@cindex logical-and, bitwise +@cindex bitwise logical-and +@item (and:@var{m} @var{x} @var{y}) +Represents the bitwise logical-and of the values represented by +@var{x} and @var{y}, carried out in machine mode @var{m}, which must be +a fixed-point machine mode. + +@findex ior +@cindex inclusive-or, bitwise +@cindex bitwise inclusive-or +@item (ior:@var{m} @var{x} @var{y}) +Represents the bitwise inclusive-or of the values represented by @var{x} +and @var{y}, carried out in machine mode @var{m}, which must be a +fixed-point mode. + +@findex xor +@cindex exclusive-or, bitwise +@cindex bitwise exclusive-or +@item (xor:@var{m} @var{x} @var{y}) +Represents the bitwise exclusive-or of the values represented by @var{x} +and @var{y}, carried out in machine mode @var{m}, which must be a +fixed-point mode. + +@findex ashift +@findex ss_ashift +@cindex left shift +@cindex shift +@cindex arithmetic shift +@cindex arithmetic shift with signed saturation +@item (ashift:@var{m} @var{x} @var{c}) +@itemx (ss_ashift:@var{m} @var{x} @var{c}) +These two expressions represent the result of arithmetically shifting @var{x} +left by @var{c} places. They differ in their behavior on overflow of integer +modes. An @code{ashift} operation is a plain shift with no special behavior +in case of a change in the sign bit; @code{ss_ashift} saturates to the minimum +or maximum representable value if any of the bits shifted out differs from the +final sign bit. + +@var{x} have mode @var{m}, a fixed-point machine mode. @var{c} +be a fixed-point mode or be a constant with mode @code{VOIDmode}; which +mode is determined by the mode called for in the machine description +entry for the left-shift instruction. For example, on the VAX, the mode +of @var{c} is @code{QImode} regardless of @var{m}. + +@findex lshiftrt +@cindex right shift +@findex ashiftrt +@item (lshiftrt:@var{m} @var{x} @var{c}) +@itemx (ashiftrt:@var{m} @var{x} @var{c}) +Like @code{ashift} but for right shift. Unlike the case for left shift, +these two operations are distinct. + +@findex rotate +@cindex rotate +@cindex left rotate +@findex rotatert +@cindex right rotate +@item (rotate:@var{m} @var{x} @var{c}) +@itemx (rotatert:@var{m} @var{x} @var{c}) +Similar but represent left and right rotate. If @var{c} is a constant, +use @code{rotate}. + +@findex abs +@cindex absolute value +@item (abs:@var{m} @var{x}) +Represents the absolute value of @var{x}, computed in mode @var{m}. + +@findex sqrt +@cindex square root +@item (sqrt:@var{m} @var{x}) +Represents the square root of @var{x}, computed in mode @var{m}. +Most often @var{m} will be a floating point mode. + +@findex ffs +@item (ffs:@var{m} @var{x}) +Represents one plus the index of the least significant 1-bit in +@var{x}, represented as an integer of mode @var{m}. (The value is +zero if @var{x} is zero.) The mode of @var{x} need not be @var{m}; +depending on the target machine, various mode combinations may be +valid. + +@findex clz +@item (clz:@var{m} @var{x}) +Represents the number of leading 0-bits in @var{x}, represented as an +integer of mode @var{m}, starting at the most significant bit position. +If @var{x} is zero, the value is determined by +@code{CLZ_DEFINED_VALUE_AT_ZERO}. Note that this is one of +the few expressions that is not invariant under widening. The mode of +@var{x} will usually be an integer mode. + +@findex ctz +@item (ctz:@var{m} @var{x}) +Represents the number of trailing 0-bits in @var{x}, represented as an +integer of mode @var{m}, starting at the least significant bit position. +If @var{x} is zero, the value is determined by +@code{CTZ_DEFINED_VALUE_AT_ZERO}. Except for this case, +@code{ctz(x)} is equivalent to @code{ffs(@var{x}) - 1}. The mode of +@var{x} will usually be an integer mode. + +@findex popcount +@item (popcount:@var{m} @var{x}) +Represents the number of 1-bits in @var{x}, represented as an integer of +mode @var{m}. The mode of @var{x} will usually be an integer mode. + +@findex parity +@item (parity:@var{m} @var{x}) +Represents the number of 1-bits modulo 2 in @var{x}, represented as an +integer of mode @var{m}. The mode of @var{x} will usually be an integer +mode. +@end table + +@node Comparisons +@section Comparison Operations +@cindex RTL comparison operations + +Comparison operators test a relation on two operands and are considered +to represent a machine-dependent nonzero value described by, but not +necessarily equal to, @code{STORE_FLAG_VALUE} (@pxref{Misc}) +if the relation holds, or zero if it does not, for comparison operators +whose results have a `MODE_INT' mode, +@code{FLOAT_STORE_FLAG_VALUE} (@pxref{Misc}) if the relation holds, or +zero if it does not, for comparison operators that return floating-point +values, and a vector of either @code{VECTOR_STORE_FLAG_VALUE} (@pxref{Misc}) +if the relation holds, or of zeros if it does not, for comparison operators +that return vector results. +The mode of the comparison operation is independent of the mode +of the data being compared. If the comparison operation is being tested +(e.g., the first operand of an @code{if_then_else}), the mode must be +@code{VOIDmode}. + +@cindex condition codes +There are two ways that comparison operations may be used. The +comparison operators may be used to compare the condition codes +@code{(cc0)} against zero, as in @code{(eq (cc0) (const_int 0))}. Such +a construct actually refers to the result of the preceding instruction +in which the condition codes were set. The instruction setting the +condition code must be adjacent to the instruction using the condition +code; only @code{note} insns may separate them. + +Alternatively, a comparison operation may directly compare two data +objects. The mode of the comparison is determined by the operands; they +must both be valid for a common machine mode. A comparison with both +operands constant would be invalid as the machine mode could not be +deduced from it, but such a comparison should never exist in RTL due to +constant folding. + +In the example above, if @code{(cc0)} were last set to +@code{(compare @var{x} @var{y})}, the comparison operation is +identical to @code{(eq @var{x} @var{y})}. Usually only one style +of comparisons is supported on a particular machine, but the combine +pass will try to merge the operations to produce the @code{eq} shown +in case it exists in the context of the particular insn involved. + +Inequality comparisons come in two flavors, signed and unsigned. Thus, +there are distinct expression codes @code{gt} and @code{gtu} for signed and +unsigned greater-than. These can produce different results for the same +pair of integer values: for example, 1 is signed greater-than @minus{}1 but not +unsigned greater-than, because @minus{}1 when regarded as unsigned is actually +@code{0xffffffff} which is greater than 1. + +The signed comparisons are also used for floating point values. Floating +point comparisons are distinguished by the machine modes of the operands. + +@table @code +@findex eq +@cindex equal +@item (eq:@var{m} @var{x} @var{y}) +@code{STORE_FLAG_VALUE} if the values represented by @var{x} and @var{y} +are equal, otherwise 0. + +@findex ne +@cindex not equal +@item (ne:@var{m} @var{x} @var{y}) +@code{STORE_FLAG_VALUE} if the values represented by @var{x} and @var{y} +are not equal, otherwise 0. + +@findex gt +@cindex greater than +@item (gt:@var{m} @var{x} @var{y}) +@code{STORE_FLAG_VALUE} if the @var{x} is greater than @var{y}. If they +are fixed-point, the comparison is done in a signed sense. + +@findex gtu +@cindex greater than +@cindex unsigned greater than +@item (gtu:@var{m} @var{x} @var{y}) +Like @code{gt} but does unsigned comparison, on fixed-point numbers only. + +@findex lt +@cindex less than +@findex ltu +@cindex unsigned less than +@item (lt:@var{m} @var{x} @var{y}) +@itemx (ltu:@var{m} @var{x} @var{y}) +Like @code{gt} and @code{gtu} but test for ``less than''. + +@findex ge +@cindex greater than +@findex geu +@cindex unsigned greater than +@item (ge:@var{m} @var{x} @var{y}) +@itemx (geu:@var{m} @var{x} @var{y}) +Like @code{gt} and @code{gtu} but test for ``greater than or equal''. + +@findex le +@cindex less than or equal +@findex leu +@cindex unsigned less than +@item (le:@var{m} @var{x} @var{y}) +@itemx (leu:@var{m} @var{x} @var{y}) +Like @code{gt} and @code{gtu} but test for ``less than or equal''. + +@findex if_then_else +@item (if_then_else @var{cond} @var{then} @var{else}) +This is not a comparison operation but is listed here because it is +always used in conjunction with a comparison operation. To be +precise, @var{cond} is a comparison expression. This expression +represents a choice, according to @var{cond}, between the value +represented by @var{then} and the one represented by @var{else}. + +On most machines, @code{if_then_else} expressions are valid only +to express conditional jumps. + +@findex cond +@item (cond [@var{test1} @var{value1} @var{test2} @var{value2} @dots{}] @var{default}) +Similar to @code{if_then_else}, but more general. Each of @var{test1}, +@var{test2}, @dots{} is performed in turn. The result of this expression is +the @var{value} corresponding to the first nonzero test, or @var{default} if +none of the tests are nonzero expressions. + +This is currently not valid for instruction patterns and is supported only +for insn attributes. @xref{Insn Attributes}. +@end table + +@node Bit-Fields +@section Bit-Fields +@cindex bit-fields + +Special expression codes exist to represent bit-field instructions. + +@table @code +@findex sign_extract +@cindex @code{BITS_BIG_ENDIAN}, effect on @code{sign_extract} +@item (sign_extract:@var{m} @var{loc} @var{size} @var{pos}) +This represents a reference to a sign-extended bit-field contained or +starting in @var{loc} (a memory or register reference). The bit-field +is @var{size} bits wide and starts at bit @var{pos}. The compilation +option @code{BITS_BIG_ENDIAN} says which end of the memory unit +@var{pos} counts from. + +If @var{loc} is in memory, its mode must be a single-byte integer mode. +If @var{loc} is in a register, the mode to use is specified by the +operand of the @code{insv} or @code{extv} pattern +(@pxref{Standard Names}) and is usually a full-word integer mode, +which is the default if none is specified. + +The mode of @var{pos} is machine-specific and is also specified +in the @code{insv} or @code{extv} pattern. + +The mode @var{m} is the same as the mode that would be used for +@var{loc} if it were a register. + +A @code{sign_extract} can not appear as an lvalue, or part thereof, +in RTL. + +@findex zero_extract +@item (zero_extract:@var{m} @var{loc} @var{size} @var{pos}) +Like @code{sign_extract} but refers to an unsigned or zero-extended +bit-field. The same sequence of bits are extracted, but they +are filled to an entire word with zeros instead of by sign-extension. + +Unlike @code{sign_extract}, this type of expressions can be lvalues +in RTL; they may appear on the left side of an assignment, indicating +insertion of a value into the specified bit-field. +@end table + +@node Vector Operations +@section Vector Operations +@cindex vector operations + +All normal RTL expressions can be used with vector modes; they are +interpreted as operating on each part of the vector independently. +Additionally, there are a few new expressions to describe specific vector +operations. + +@table @code +@findex vec_merge +@item (vec_merge:@var{m} @var{vec1} @var{vec2} @var{items}) +This describes a merge operation between two vectors. The result is a vector +of mode @var{m}; its elements are selected from either @var{vec1} or +@var{vec2}. Which elements are selected is described by @var{items}, which +is a bit mask represented by a @code{const_int}; a zero bit indicates the +corresponding element in the result vector is taken from @var{vec2} while +a set bit indicates it is taken from @var{vec1}. + +@findex vec_select +@item (vec_select:@var{m} @var{vec1} @var{selection}) +This describes an operation that selects parts of a vector. @var{vec1} is +the source vector, @var{selection} is a @code{parallel} that contains a +@code{const_int} for each of the subparts of the result vector, giving the +number of the source subpart that should be stored into it. + +@findex vec_concat +@item (vec_concat:@var{m} @var{vec1} @var{vec2}) +Describes a vector concat operation. The result is a concatenation of the +vectors @var{vec1} and @var{vec2}; its length is the sum of the lengths of +the two inputs. + +@findex vec_duplicate +@item (vec_duplicate:@var{m} @var{vec}) +This operation converts a small vector into a larger one by duplicating the +input values. The output vector mode must have the same submodes as the +input vector mode, and the number of output parts must be an integer multiple +of the number of input parts. + +@end table + +@node Conversions +@section Conversions +@cindex conversions +@cindex machine mode conversions + +All conversions between machine modes must be represented by +explicit conversion operations. For example, an expression +which is the sum of a byte and a full word cannot be written as +@code{(plus:SI (reg:QI 34) (reg:SI 80))} because the @code{plus} +operation requires two operands of the same machine mode. +Therefore, the byte-sized operand is enclosed in a conversion +operation, as in + +@smallexample +(plus:SI (sign_extend:SI (reg:QI 34)) (reg:SI 80)) +@end smallexample + +The conversion operation is not a mere placeholder, because there +may be more than one way of converting from a given starting mode +to the desired final mode. The conversion operation code says how +to do it. + +For all conversion operations, @var{x} must not be @code{VOIDmode} +because the mode in which to do the conversion would not be known. +The conversion must either be done at compile-time or @var{x} +must be placed into a register. + +@table @code +@findex sign_extend +@item (sign_extend:@var{m} @var{x}) +Represents the result of sign-extending the value @var{x} +to machine mode @var{m}. @var{m} must be a fixed-point mode +and @var{x} a fixed-point value of a mode narrower than @var{m}. + +@findex zero_extend +@item (zero_extend:@var{m} @var{x}) +Represents the result of zero-extending the value @var{x} +to machine mode @var{m}. @var{m} must be a fixed-point mode +and @var{x} a fixed-point value of a mode narrower than @var{m}. + +@findex float_extend +@item (float_extend:@var{m} @var{x}) +Represents the result of extending the value @var{x} +to machine mode @var{m}. @var{m} must be a floating point mode +and @var{x} a floating point value of a mode narrower than @var{m}. + +@findex truncate +@item (truncate:@var{m} @var{x}) +Represents the result of truncating the value @var{x} +to machine mode @var{m}. @var{m} must be a fixed-point mode +and @var{x} a fixed-point value of a mode wider than @var{m}. + +@findex ss_truncate +@item (ss_truncate:@var{m} @var{x}) +Represents the result of truncating the value @var{x} +to machine mode @var{m}, using signed saturation in the case of +overflow. Both @var{m} and the mode of @var{x} must be fixed-point +modes. + +@findex us_truncate +@item (us_truncate:@var{m} @var{x}) +Represents the result of truncating the value @var{x} +to machine mode @var{m}, using unsigned saturation in the case of +overflow. Both @var{m} and the mode of @var{x} must be fixed-point +modes. + +@findex float_truncate +@item (float_truncate:@var{m} @var{x}) +Represents the result of truncating the value @var{x} +to machine mode @var{m}. @var{m} must be a floating point mode +and @var{x} a floating point value of a mode wider than @var{m}. + +@findex float +@item (float:@var{m} @var{x}) +Represents the result of converting fixed point value @var{x}, +regarded as signed, to floating point mode @var{m}. + +@findex unsigned_float +@item (unsigned_float:@var{m} @var{x}) +Represents the result of converting fixed point value @var{x}, +regarded as unsigned, to floating point mode @var{m}. + +@findex fix +@item (fix:@var{m} @var{x}) +When @var{m} is a fixed point mode, represents the result of +converting floating point value @var{x} to mode @var{m}, regarded as +signed. How rounding is done is not specified, so this operation may +be used validly in compiling C code only for integer-valued operands. + +@findex unsigned_fix +@item (unsigned_fix:@var{m} @var{x}) +Represents the result of converting floating point value @var{x} to +fixed point mode @var{m}, regarded as unsigned. How rounding is done +is not specified. + +@findex fix +@item (fix:@var{m} @var{x}) +When @var{m} is a floating point mode, represents the result of +converting floating point value @var{x} (valid for mode @var{m}) to an +integer, still represented in floating point mode @var{m}, by rounding +towards zero. +@end table + +@node RTL Declarations +@section Declarations +@cindex RTL declarations +@cindex declarations, RTL + +Declaration expression codes do not represent arithmetic operations +but rather state assertions about their operands. + +@table @code +@findex strict_low_part +@cindex @code{subreg}, in @code{strict_low_part} +@item (strict_low_part (subreg:@var{m} (reg:@var{n} @var{r}) 0)) +This expression code is used in only one context: as the destination operand of a +@code{set} expression. In addition, the operand of this expression +must be a non-paradoxical @code{subreg} expression. + +The presence of @code{strict_low_part} says that the part of the +register which is meaningful in mode @var{n}, but is not part of +mode @var{m}, is not to be altered. Normally, an assignment to such +a subreg is allowed to have undefined effects on the rest of the +register when @var{m} is less than a word. +@end table + +@node Side Effects +@section Side Effect Expressions +@cindex RTL side effect expressions + +The expression codes described so far represent values, not actions. +But machine instructions never produce values; they are meaningful +only for their side effects on the state of the machine. Special +expression codes are used to represent side effects. + +The body of an instruction is always one of these side effect codes; +the codes described above, which represent values, appear only as +the operands of these. + +@table @code +@findex set +@item (set @var{lval} @var{x}) +Represents the action of storing the value of @var{x} into the place +represented by @var{lval}. @var{lval} must be an expression +representing a place that can be stored in: @code{reg} (or @code{subreg}, +@code{strict_low_part} or @code{zero_extract}), @code{mem}, @code{pc}, +@code{parallel}, or @code{cc0}. + +If @var{lval} is a @code{reg}, @code{subreg} or @code{mem}, it has a +machine mode; then @var{x} must be valid for that mode. + +If @var{lval} is a @code{reg} whose machine mode is less than the full +width of the register, then it means that the part of the register +specified by the machine mode is given the specified value and the +rest of the register receives an undefined value. Likewise, if +@var{lval} is a @code{subreg} whose machine mode is narrower than +the mode of the register, the rest of the register can be changed in +an undefined way. + +If @var{lval} is a @code{strict_low_part} of a subreg, then the part +of the register specified by the machine mode of the @code{subreg} is +given the value @var{x} and the rest of the register is not changed. + +If @var{lval} is a @code{zero_extract}, then the referenced part of +the bit-field (a memory or register reference) specified by the +@code{zero_extract} is given the value @var{x} and the rest of the +bit-field is not changed. Note that @code{sign_extract} can not +appear in @var{lval}. + +If @var{lval} is @code{(cc0)}, it has no machine mode, and @var{x} may +be either a @code{compare} expression or a value that may have any mode. +The latter case represents a ``test'' instruction. The expression +@code{(set (cc0) (reg:@var{m} @var{n}))} is equivalent to +@code{(set (cc0) (compare (reg:@var{m} @var{n}) (const_int 0)))}. +Use the former expression to save space during the compilation. + +If @var{lval} is a @code{parallel}, it is used to represent the case of +a function returning a structure in multiple registers. Each element +of the @code{parallel} is an @code{expr_list} whose first operand is a +@code{reg} and whose second operand is a @code{const_int} representing the +offset (in bytes) into the structure at which the data in that register +corresponds. The first element may be null to indicate that the structure +is also passed partly in memory. + +@cindex jump instructions and @code{set} +@cindex @code{if_then_else} usage +If @var{lval} is @code{(pc)}, we have a jump instruction, and the +possibilities for @var{x} are very limited. It may be a +@code{label_ref} expression (unconditional jump). It may be an +@code{if_then_else} (conditional jump), in which case either the +second or the third operand must be @code{(pc)} (for the case which +does not jump) and the other of the two must be a @code{label_ref} +(for the case which does jump). @var{x} may also be a @code{mem} or +@code{(plus:SI (pc) @var{y})}, where @var{y} may be a @code{reg} or a +@code{mem}; these unusual patterns are used to represent jumps through +branch tables. + +If @var{lval} is neither @code{(cc0)} nor @code{(pc)}, the mode of +@var{lval} must not be @code{VOIDmode} and the mode of @var{x} must be +valid for the mode of @var{lval}. + +@findex SET_DEST +@findex SET_SRC +@var{lval} is customarily accessed with the @code{SET_DEST} macro and +@var{x} with the @code{SET_SRC} macro. + +@findex return +@item (return) +As the sole expression in a pattern, represents a return from the +current function, on machines where this can be done with one +instruction, such as VAXen. On machines where a multi-instruction +``epilogue'' must be executed in order to return from the function, +returning is done by jumping to a label which precedes the epilogue, and +the @code{return} expression code is never used. + +Inside an @code{if_then_else} expression, represents the value to be +placed in @code{pc} to return to the caller. + +Note that an insn pattern of @code{(return)} is logically equivalent to +@code{(set (pc) (return))}, but the latter form is never used. + +@findex call +@item (call @var{function} @var{nargs}) +Represents a function call. @var{function} is a @code{mem} expression +whose address is the address of the function to be called. +@var{nargs} is an expression which can be used for two purposes: on +some machines it represents the number of bytes of stack argument; on +others, it represents the number of argument registers. + +Each machine has a standard machine mode which @var{function} must +have. The machine description defines macro @code{FUNCTION_MODE} to +expand into the requisite mode name. The purpose of this mode is to +specify what kind of addressing is allowed, on machines where the +allowed kinds of addressing depend on the machine mode being +addressed. + +@findex clobber +@item (clobber @var{x}) +Represents the storing or possible storing of an unpredictable, +undescribed value into @var{x}, which must be a @code{reg}, +@code{scratch}, @code{parallel} or @code{mem} expression. + +One place this is used is in string instructions that store standard +values into particular hard registers. It may not be worth the +trouble to describe the values that are stored, but it is essential to +inform the compiler that the registers will be altered, lest it +attempt to keep data in them across the string instruction. + +If @var{x} is @code{(mem:BLK (const_int 0))} or +@code{(mem:BLK (scratch))}, it means that all memory +locations must be presumed clobbered. If @var{x} is a @code{parallel}, +it has the same meaning as a @code{parallel} in a @code{set} expression. + +Note that the machine description classifies certain hard registers as +``call-clobbered''. All function call instructions are assumed by +default to clobber these registers, so there is no need to use +@code{clobber} expressions to indicate this fact. Also, each function +call is assumed to have the potential to alter any memory location, +unless the function is declared @code{const}. + +If the last group of expressions in a @code{parallel} are each a +@code{clobber} expression whose arguments are @code{reg} or +@code{match_scratch} (@pxref{RTL Template}) expressions, the combiner +phase can add the appropriate @code{clobber} expressions to an insn it +has constructed when doing so will cause a pattern to be matched. + +This feature can be used, for example, on a machine that whose multiply +and add instructions don't use an MQ register but which has an +add-accumulate instruction that does clobber the MQ register. Similarly, +a combined instruction might require a temporary register while the +constituent instructions might not. + +When a @code{clobber} expression for a register appears inside a +@code{parallel} with other side effects, the register allocator +guarantees that the register is unoccupied both before and after that +insn. However, the reload phase may allocate a register used for one of +the inputs unless the @samp{&} constraint is specified for the selected +alternative (@pxref{Modifiers}). You can clobber either a specific hard +register, a pseudo register, or a @code{scratch} expression; in the +latter two cases, GCC will allocate a hard register that is available +there for use as a temporary. + +For instructions that require a temporary register, you should use +@code{scratch} instead of a pseudo-register because this will allow the +combiner phase to add the @code{clobber} when required. You do this by +coding (@code{clobber} (@code{match_scratch} @dots{})). If you do +clobber a pseudo register, use one which appears nowhere else---generate +a new one each time. Otherwise, you may confuse CSE@. + +There is one other known use for clobbering a pseudo register in a +@code{parallel}: when one of the input operands of the insn is also +clobbered by the insn. In this case, using the same pseudo register in +the clobber and elsewhere in the insn produces the expected results. + +@findex use +@item (use @var{x}) +Represents the use of the value of @var{x}. It indicates that the +value in @var{x} at this point in the program is needed, even though +it may not be apparent why this is so. Therefore, the compiler will +not attempt to delete previous instructions whose only effect is to +store a value in @var{x}. @var{x} must be a @code{reg} expression. + +In some situations, it may be tempting to add a @code{use} of a +register in a @code{parallel} to describe a situation where the value +of a special register will modify the behavior of the instruction. +An hypothetical example might be a pattern for an addition that can +either wrap around or use saturating addition depending on the value +of a special control register: + +@smallexample +(parallel [(set (reg:SI 2) (unspec:SI [(reg:SI 3) + (reg:SI 4)] 0)) + (use (reg:SI 1))]) +@end smallexample + +@noindent + +This will not work, several of the optimizers only look at expressions +locally; it is very likely that if you have multiple insns with +identical inputs to the @code{unspec}, they will be optimized away even +if register 1 changes in between. + +This means that @code{use} can @emph{only} be used to describe +that the register is live. You should think twice before adding +@code{use} statements, more often you will want to use @code{unspec} +instead. The @code{use} RTX is most commonly useful to describe that +a fixed register is implicitly used in an insn. It is also safe to use +in patterns where the compiler knows for other reasons that the result +of the whole pattern is variable, such as @samp{movmem@var{m}} or +@samp{call} patterns. + +During the reload phase, an insn that has a @code{use} as pattern +can carry a reg_equal note. These @code{use} insns will be deleted +before the reload phase exits. + +During the delayed branch scheduling phase, @var{x} may be an insn. +This indicates that @var{x} previously was located at this place in the +code and its data dependencies need to be taken into account. These +@code{use} insns will be deleted before the delayed branch scheduling +phase exits. + +@findex parallel +@item (parallel [@var{x0} @var{x1} @dots{}]) +Represents several side effects performed in parallel. The square +brackets stand for a vector; the operand of @code{parallel} is a +vector of expressions. @var{x0}, @var{x1} and so on are individual +side effect expressions---expressions of code @code{set}, @code{call}, +@code{return}, @code{clobber} or @code{use}. + +``In parallel'' means that first all the values used in the individual +side-effects are computed, and second all the actual side-effects are +performed. For example, + +@smallexample +(parallel [(set (reg:SI 1) (mem:SI (reg:SI 1))) + (set (mem:SI (reg:SI 1)) (reg:SI 1))]) +@end smallexample + +@noindent +says unambiguously that the values of hard register 1 and the memory +location addressed by it are interchanged. In both places where +@code{(reg:SI 1)} appears as a memory address it refers to the value +in register 1 @emph{before} the execution of the insn. + +It follows that it is @emph{incorrect} to use @code{parallel} and +expect the result of one @code{set} to be available for the next one. +For example, people sometimes attempt to represent a jump-if-zero +instruction this way: + +@smallexample +(parallel [(set (cc0) (reg:SI 34)) + (set (pc) (if_then_else + (eq (cc0) (const_int 0)) + (label_ref @dots{}) + (pc)))]) +@end smallexample + +@noindent +But this is incorrect, because it says that the jump condition depends +on the condition code value @emph{before} this instruction, not on the +new value that is set by this instruction. + +@cindex peephole optimization, RTL representation +Peephole optimization, which takes place together with final assembly +code output, can produce insns whose patterns consist of a @code{parallel} +whose elements are the operands needed to output the resulting +assembler code---often @code{reg}, @code{mem} or constant expressions. +This would not be well-formed RTL at any other stage in compilation, +but it is ok then because no further optimization remains to be done. +However, the definition of the macro @code{NOTICE_UPDATE_CC}, if +any, must deal with such insns if you define any peephole optimizations. + +@findex cond_exec +@item (cond_exec [@var{cond} @var{expr}]) +Represents a conditionally executed expression. The @var{expr} is +executed only if the @var{cond} is nonzero. The @var{cond} expression +must not have side-effects, but the @var{expr} may very well have +side-effects. + +@findex sequence +@item (sequence [@var{insns} @dots{}]) +Represents a sequence of insns. Each of the @var{insns} that appears +in the vector is suitable for appearing in the chain of insns, so it +must be an @code{insn}, @code{jump_insn}, @code{call_insn}, +@code{code_label}, @code{barrier} or @code{note}. + +A @code{sequence} RTX is never placed in an actual insn during RTL +generation. It represents the sequence of insns that result from a +@code{define_expand} @emph{before} those insns are passed to +@code{emit_insn} to insert them in the chain of insns. When actually +inserted, the individual sub-insns are separated out and the +@code{sequence} is forgotten. + +After delay-slot scheduling is completed, an insn and all the insns that +reside in its delay slots are grouped together into a @code{sequence}. +The insn requiring the delay slot is the first insn in the vector; +subsequent insns are to be placed in the delay slot. + +@code{INSN_ANNULLED_BRANCH_P} is set on an insn in a delay slot to +indicate that a branch insn should be used that will conditionally annul +the effect of the insns in the delay slots. In such a case, +@code{INSN_FROM_TARGET_P} indicates that the insn is from the target of +the branch and should be executed only if the branch is taken; otherwise +the insn should be executed only if the branch is not taken. +@xref{Delay Slots}. +@end table + +These expression codes appear in place of a side effect, as the body of +an insn, though strictly speaking they do not always describe side +effects as such: + +@table @code +@findex asm_input +@item (asm_input @var{s}) +Represents literal assembler code as described by the string @var{s}. + +@findex unspec +@findex unspec_volatile +@item (unspec [@var{operands} @dots{}] @var{index}) +@itemx (unspec_volatile [@var{operands} @dots{}] @var{index}) +Represents a machine-specific operation on @var{operands}. @var{index} +selects between multiple machine-specific operations. +@code{unspec_volatile} is used for volatile operations and operations +that may trap; @code{unspec} is used for other operations. + +These codes may appear inside a @code{pattern} of an +insn, inside a @code{parallel}, or inside an expression. + +@findex addr_vec +@item (addr_vec:@var{m} [@var{lr0} @var{lr1} @dots{}]) +Represents a table of jump addresses. The vector elements @var{lr0}, +etc., are @code{label_ref} expressions. The mode @var{m} specifies +how much space is given to each address; normally @var{m} would be +@code{Pmode}. + +@findex addr_diff_vec +@item (addr_diff_vec:@var{m} @var{base} [@var{lr0} @var{lr1} @dots{}] @var{min} @var{max} @var{flags}) +Represents a table of jump addresses expressed as offsets from +@var{base}. The vector elements @var{lr0}, etc., are @code{label_ref} +expressions and so is @var{base}. The mode @var{m} specifies how much +space is given to each address-difference. @var{min} and @var{max} +are set up by branch shortening and hold a label with a minimum and a +maximum address, respectively. @var{flags} indicates the relative +position of @var{base}, @var{min} and @var{max} to the containing insn +and of @var{min} and @var{max} to @var{base}. See rtl.def for details. + +@findex prefetch +@item (prefetch:@var{m} @var{addr} @var{rw} @var{locality}) +Represents prefetch of memory at address @var{addr}. +Operand @var{rw} is 1 if the prefetch is for data to be written, 0 otherwise; +targets that do not support write prefetches should treat this as a normal +prefetch. +Operand @var{locality} specifies the amount of temporal locality; 0 if there +is none or 1, 2, or 3 for increasing levels of temporal locality; +targets that do not support locality hints should ignore this. + +This insn is used to minimize cache-miss latency by moving data into a +cache before it is accessed. It should use only non-faulting data prefetch +instructions. +@end table + +@node Incdec +@section Embedded Side-Effects on Addresses +@cindex RTL preincrement +@cindex RTL postincrement +@cindex RTL predecrement +@cindex RTL postdecrement + +Six special side-effect expression codes appear as memory addresses. + +@table @code +@findex pre_dec +@item (pre_dec:@var{m} @var{x}) +Represents the side effect of decrementing @var{x} by a standard +amount and represents also the value that @var{x} has after being +decremented. @var{x} must be a @code{reg} or @code{mem}, but most +machines allow only a @code{reg}. @var{m} must be the machine mode +for pointers on the machine in use. The amount @var{x} is decremented +by is the length in bytes of the machine mode of the containing memory +reference of which this expression serves as the address. Here is an +example of its use: + +@smallexample +(mem:DF (pre_dec:SI (reg:SI 39))) +@end smallexample + +@noindent +This says to decrement pseudo register 39 by the length of a @code{DFmode} +value and use the result to address a @code{DFmode} value. + +@findex pre_inc +@item (pre_inc:@var{m} @var{x}) +Similar, but specifies incrementing @var{x} instead of decrementing it. + +@findex post_dec +@item (post_dec:@var{m} @var{x}) +Represents the same side effect as @code{pre_dec} but a different +value. The value represented here is the value @var{x} has @i{before} +being decremented. + +@findex post_inc +@item (post_inc:@var{m} @var{x}) +Similar, but specifies incrementing @var{x} instead of decrementing it. + +@findex post_modify +@item (post_modify:@var{m} @var{x} @var{y}) + +Represents the side effect of setting @var{x} to @var{y} and +represents @var{x} before @var{x} is modified. @var{x} must be a +@code{reg} or @code{mem}, but most machines allow only a @code{reg}. +@var{m} must be the machine mode for pointers on the machine in use. + +The expression @var{y} must be one of three forms: +@table @code +@code{(plus:@var{m} @var{x} @var{z})}, +@code{(minus:@var{m} @var{x} @var{z})}, or +@code{(plus:@var{m} @var{x} @var{i})}, +@end table +where @var{z} is an index register and @var{i} is a constant. + +Here is an example of its use: + +@smallexample +(mem:SF (post_modify:SI (reg:SI 42) (plus (reg:SI 42) + (reg:SI 48)))) +@end smallexample + +This says to modify pseudo register 42 by adding the contents of pseudo +register 48 to it, after the use of what ever 42 points to. + +@findex pre_modify +@item (pre_modify:@var{m} @var{x} @var{expr}) +Similar except side effects happen before the use. +@end table + +These embedded side effect expressions must be used with care. Instruction +patterns may not use them. Until the @samp{flow} pass of the compiler, +they may occur only to represent pushes onto the stack. The @samp{flow} +pass finds cases where registers are incremented or decremented in one +instruction and used as an address shortly before or after; these cases are +then transformed to use pre- or post-increment or -decrement. + +If a register used as the operand of these expressions is used in +another address in an insn, the original value of the register is used. +Uses of the register outside of an address are not permitted within the +same insn as a use in an embedded side effect expression because such +insns behave differently on different machines and hence must be treated +as ambiguous and disallowed. + +An instruction that can be represented with an embedded side effect +could also be represented using @code{parallel} containing an additional +@code{set} to describe how the address register is altered. This is not +done because machines that allow these operations at all typically +allow them wherever a memory address is called for. Describing them as +additional parallel stores would require doubling the number of entries +in the machine description. + +@node Assembler +@section Assembler Instructions as Expressions +@cindex assembler instructions in RTL + +@cindex @code{asm_operands}, usage +The RTX code @code{asm_operands} represents a value produced by a +user-specified assembler instruction. It is used to represent +an @code{asm} statement with arguments. An @code{asm} statement with +a single output operand, like this: + +@smallexample +asm ("foo %1,%2,%0" : "=a" (outputvar) : "g" (x + y), "di" (*z)); +@end smallexample + +@noindent +is represented using a single @code{asm_operands} RTX which represents +the value that is stored in @code{outputvar}: + +@smallexample +(set @var{rtx-for-outputvar} + (asm_operands "foo %1,%2,%0" "a" 0 + [@var{rtx-for-addition-result} @var{rtx-for-*z}] + [(asm_input:@var{m1} "g") + (asm_input:@var{m2} "di")])) +@end smallexample + +@noindent +Here the operands of the @code{asm_operands} RTX are the assembler +template string, the output-operand's constraint, the index-number of the +output operand among the output operands specified, a vector of input +operand RTX's, and a vector of input-operand modes and constraints. The +mode @var{m1} is the mode of the sum @code{x+y}; @var{m2} is that of +@code{*z}. + +When an @code{asm} statement has multiple output values, its insn has +several such @code{set} RTX's inside of a @code{parallel}. Each @code{set} +contains a @code{asm_operands}; all of these share the same assembler +template and vectors, but each contains the constraint for the respective +output operand. They are also distinguished by the output-operand index +number, which is 0, 1, @dots{} for successive output operands. + +@node Insns +@section Insns +@cindex insns + +The RTL representation of the code for a function is a doubly-linked +chain of objects called @dfn{insns}. Insns are expressions with +special codes that are used for no other purpose. Some insns are +actual instructions; others represent dispatch tables for @code{switch} +statements; others represent labels to jump to or various sorts of +declarative information. + +In addition to its own specific data, each insn must have a unique +id-number that distinguishes it from all other insns in the current +function (after delayed branch scheduling, copies of an insn with the +same id-number may be present in multiple places in a function, but +these copies will always be identical and will only appear inside a +@code{sequence}), and chain pointers to the preceding and following +insns. These three fields occupy the same position in every insn, +independent of the expression code of the insn. They could be accessed +with @code{XEXP} and @code{XINT}, but instead three special macros are +always used: + +@table @code +@findex INSN_UID +@item INSN_UID (@var{i}) +Accesses the unique id of insn @var{i}. + +@findex PREV_INSN +@item PREV_INSN (@var{i}) +Accesses the chain pointer to the insn preceding @var{i}. +If @var{i} is the first insn, this is a null pointer. + +@findex NEXT_INSN +@item NEXT_INSN (@var{i}) +Accesses the chain pointer to the insn following @var{i}. +If @var{i} is the last insn, this is a null pointer. +@end table + +@findex get_insns +@findex get_last_insn +The first insn in the chain is obtained by calling @code{get_insns}; the +last insn is the result of calling @code{get_last_insn}. Within the +chain delimited by these insns, the @code{NEXT_INSN} and +@code{PREV_INSN} pointers must always correspond: if @var{insn} is not +the first insn, + +@smallexample +NEXT_INSN (PREV_INSN (@var{insn})) == @var{insn} +@end smallexample + +@noindent +is always true and if @var{insn} is not the last insn, + +@smallexample +PREV_INSN (NEXT_INSN (@var{insn})) == @var{insn} +@end smallexample + +@noindent +is always true. + +After delay slot scheduling, some of the insns in the chain might be +@code{sequence} expressions, which contain a vector of insns. The value +of @code{NEXT_INSN} in all but the last of these insns is the next insn +in the vector; the value of @code{NEXT_INSN} of the last insn in the vector +is the same as the value of @code{NEXT_INSN} for the @code{sequence} in +which it is contained. Similar rules apply for @code{PREV_INSN}. + +This means that the above invariants are not necessarily true for insns +inside @code{sequence} expressions. Specifically, if @var{insn} is the +first insn in a @code{sequence}, @code{NEXT_INSN (PREV_INSN (@var{insn}))} +is the insn containing the @code{sequence} expression, as is the value +of @code{PREV_INSN (NEXT_INSN (@var{insn}))} if @var{insn} is the last +insn in the @code{sequence} expression. You can use these expressions +to find the containing @code{sequence} expression. + +Every insn has one of the following six expression codes: + +@table @code +@findex insn +@item insn +The expression code @code{insn} is used for instructions that do not jump +and do not do function calls. @code{sequence} expressions are always +contained in insns with code @code{insn} even if one of those insns +should jump or do function calls. + +Insns with code @code{insn} have four additional fields beyond the three +mandatory ones listed above. These four are described in a table below. + +@findex jump_insn +@item jump_insn +The expression code @code{jump_insn} is used for instructions that may +jump (or, more generally, may contain @code{label_ref} expressions). If +there is an instruction to return from the current function, it is +recorded as a @code{jump_insn}. + +@findex JUMP_LABEL +@code{jump_insn} insns have the same extra fields as @code{insn} insns, +accessed in the same way and in addition contain a field +@code{JUMP_LABEL} which is defined once jump optimization has completed. + +For simple conditional and unconditional jumps, this field contains +the @code{code_label} to which this insn will (possibly conditionally) +branch. In a more complex jump, @code{JUMP_LABEL} records one of the +labels that the insn refers to; the only way to find the others is to +scan the entire body of the insn. In an @code{addr_vec}, +@code{JUMP_LABEL} is @code{NULL_RTX}. + +Return insns count as jumps, but since they do not refer to any +labels, their @code{JUMP_LABEL} is @code{NULL_RTX}. + +@findex call_insn +@item call_insn +The expression code @code{call_insn} is used for instructions that may do +function calls. It is important to distinguish these instructions because +they imply that certain registers and memory locations may be altered +unpredictably. + +@findex CALL_INSN_FUNCTION_USAGE +@code{call_insn} insns have the same extra fields as @code{insn} insns, +accessed in the same way and in addition contain a field +@code{CALL_INSN_FUNCTION_USAGE}, which contains a list (chain of +@code{expr_list} expressions) containing @code{use} and @code{clobber} +expressions that denote hard registers and @code{MEM}s used or +clobbered by the called function. + +A @code{MEM} generally points to a stack slots in which arguments passed +to the libcall by reference (@pxref{Register Arguments, +TARGET_PASS_BY_REFERENCE}) are stored. If the argument is +caller-copied (@pxref{Register Arguments, TARGET_CALLEE_COPIES}), +the stack slot will be mentioned in @code{CLOBBER} and @code{USE} +entries; if it's callee-copied, only a @code{USE} will appear, and the +@code{MEM} may point to addresses that are not stack slots. + +@code{CLOBBER}ed registers in this list augment registers specified in +@code{CALL_USED_REGISTERS} (@pxref{Register Basics}). + +@findex code_label +@findex CODE_LABEL_NUMBER +@item code_label +A @code{code_label} insn represents a label that a jump insn can jump +to. It contains two special fields of data in addition to the three +standard ones. @code{CODE_LABEL_NUMBER} is used to hold the @dfn{label +number}, a number that identifies this label uniquely among all the +labels in the compilation (not just in the current function). +Ultimately, the label is represented in the assembler output as an +assembler label, usually of the form @samp{L@var{n}} where @var{n} is +the label number. + +When a @code{code_label} appears in an RTL expression, it normally +appears within a @code{label_ref} which represents the address of +the label, as a number. + +Besides as a @code{code_label}, a label can also be represented as a +@code{note} of type @code{NOTE_INSN_DELETED_LABEL}. + +@findex LABEL_NUSES +The field @code{LABEL_NUSES} is only defined once the jump optimization +phase is completed. It contains the number of times this label is +referenced in the current function. + +@findex LABEL_KIND +@findex SET_LABEL_KIND +@findex LABEL_ALT_ENTRY_P +@cindex alternate entry points +The field @code{LABEL_KIND} differentiates four different types of +labels: @code{LABEL_NORMAL}, @code{LABEL_STATIC_ENTRY}, +@code{LABEL_GLOBAL_ENTRY}, and @code{LABEL_WEAK_ENTRY}. The only labels +that do not have type @code{LABEL_NORMAL} are @dfn{alternate entry +points} to the current function. These may be static (visible only in +the containing translation unit), global (exposed to all translation +units), or weak (global, but can be overridden by another symbol with the +same name). + +Much of the compiler treats all four kinds of label identically. Some +of it needs to know whether or not a label is an alternate entry point; +for this purpose, the macro @code{LABEL_ALT_ENTRY_P} is provided. It is +equivalent to testing whether @samp{LABEL_KIND (label) == LABEL_NORMAL}. +The only place that cares about the distinction between static, global, +and weak alternate entry points, besides the front-end code that creates +them, is the function @code{output_alternate_entry_point}, in +@file{final.c}. + +To set the kind of a label, use the @code{SET_LABEL_KIND} macro. + +@findex barrier +@item barrier +Barriers are placed in the instruction stream when control cannot flow +past them. They are placed after unconditional jump instructions to +indicate that the jumps are unconditional and after calls to +@code{volatile} functions, which do not return (e.g., @code{exit}). +They contain no information beyond the three standard fields. + +@findex note +@findex NOTE_LINE_NUMBER +@findex NOTE_SOURCE_FILE +@item note +@code{note} insns are used to represent additional debugging and +declarative information. They contain two nonstandard fields, an +integer which is accessed with the macro @code{NOTE_LINE_NUMBER} and a +string accessed with @code{NOTE_SOURCE_FILE}. + +If @code{NOTE_LINE_NUMBER} is positive, the note represents the +position of a source line and @code{NOTE_SOURCE_FILE} is the source file name +that the line came from. These notes control generation of line +number data in the assembler output. + +Otherwise, @code{NOTE_LINE_NUMBER} is not really a line number but a +code with one of the following values (and @code{NOTE_SOURCE_FILE} +must contain a null pointer): + +@table @code +@findex NOTE_INSN_DELETED +@item NOTE_INSN_DELETED +Such a note is completely ignorable. Some passes of the compiler +delete insns by altering them into notes of this kind. + +@findex NOTE_INSN_DELETED_LABEL +@item NOTE_INSN_DELETED_LABEL +This marks what used to be a @code{code_label}, but was not used for other +purposes than taking its address and was transformed to mark that no +code jumps to it. + +@findex NOTE_INSN_BLOCK_BEG +@findex NOTE_INSN_BLOCK_END +@item NOTE_INSN_BLOCK_BEG +@itemx NOTE_INSN_BLOCK_END +These types of notes indicate the position of the beginning and end +of a level of scoping of variable names. They control the output +of debugging information. + +@findex NOTE_INSN_EH_REGION_BEG +@findex NOTE_INSN_EH_REGION_END +@item NOTE_INSN_EH_REGION_BEG +@itemx NOTE_INSN_EH_REGION_END +These types of notes indicate the position of the beginning and end of a +level of scoping for exception handling. @code{NOTE_BLOCK_NUMBER} +identifies which @code{CODE_LABEL} or @code{note} of type +@code{NOTE_INSN_DELETED_LABEL} is associated with the given region. + +@findex NOTE_INSN_LOOP_BEG +@findex NOTE_INSN_LOOP_END +@item NOTE_INSN_LOOP_BEG +@itemx NOTE_INSN_LOOP_END +These types of notes indicate the position of the beginning and end +of a @code{while} or @code{for} loop. They enable the loop optimizer +to find loops quickly. + +@findex NOTE_INSN_LOOP_CONT +@item NOTE_INSN_LOOP_CONT +Appears at the place in a loop that @code{continue} statements jump to. + +@findex NOTE_INSN_LOOP_VTOP +@item NOTE_INSN_LOOP_VTOP +This note indicates the place in a loop where the exit test begins for +those loops in which the exit test has been duplicated. This position +becomes another virtual start of the loop when considering loop +invariants. + +@findex NOTE_INSN_FUNCTION_BEG +@item NOTE_INSN_FUNCTION_BEG +Appears at the start of the function body, after the function +prologue. + +@findex NOTE_INSN_FUNCTION_END +@item NOTE_INSN_FUNCTION_END +Appears near the end of the function body, just before the label that +@code{return} statements jump to (on machine where a single instruction +does not suffice for returning). This note may be deleted by jump +optimization. + +@end table + +These codes are printed symbolically when they appear in debugging dumps. +@end table + +@cindex @code{TImode}, in @code{insn} +@cindex @code{HImode}, in @code{insn} +@cindex @code{QImode}, in @code{insn} +The machine mode of an insn is normally @code{VOIDmode}, but some +phases use the mode for various purposes. + +The common subexpression elimination pass sets the mode of an insn to +@code{QImode} when it is the first insn in a block that has already +been processed. + +The second Haifa scheduling pass, for targets that can multiple issue, +sets the mode of an insn to @code{TImode} when it is believed that the +instruction begins an issue group. That is, when the instruction +cannot issue simultaneously with the previous. This may be relied on +by later passes, in particular machine-dependent reorg. + +Here is a table of the extra fields of @code{insn}, @code{jump_insn} +and @code{call_insn} insns: + +@table @code +@findex PATTERN +@item PATTERN (@var{i}) +An expression for the side effect performed by this insn. This must be +one of the following codes: @code{set}, @code{call}, @code{use}, +@code{clobber}, @code{return}, @code{asm_input}, @code{asm_output}, +@code{addr_vec}, @code{addr_diff_vec}, @code{trap_if}, @code{unspec}, +@code{unspec_volatile}, @code{parallel}, @code{cond_exec}, or @code{sequence}. If it is a @code{parallel}, +each element of the @code{parallel} must be one these codes, except that +@code{parallel} expressions cannot be nested and @code{addr_vec} and +@code{addr_diff_vec} are not permitted inside a @code{parallel} expression. + +@findex INSN_CODE +@item INSN_CODE (@var{i}) +An integer that says which pattern in the machine description matches +this insn, or @minus{}1 if the matching has not yet been attempted. + +Such matching is never attempted and this field remains @minus{}1 on an insn +whose pattern consists of a single @code{use}, @code{clobber}, +@code{asm_input}, @code{addr_vec} or @code{addr_diff_vec} expression. + +@findex asm_noperands +Matching is also never attempted on insns that result from an @code{asm} +statement. These contain at least one @code{asm_operands} expression. +The function @code{asm_noperands} returns a non-negative value for +such insns. + +In the debugging output, this field is printed as a number followed by +a symbolic representation that locates the pattern in the @file{md} +file as some small positive or negative offset from a named pattern. + +@findex LOG_LINKS +@item LOG_LINKS (@var{i}) +A list (chain of @code{insn_list} expressions) giving information about +dependencies between instructions within a basic block. Neither a jump +nor a label may come between the related insns. + +@findex REG_NOTES +@item REG_NOTES (@var{i}) +A list (chain of @code{expr_list} and @code{insn_list} expressions) +giving miscellaneous information about the insn. It is often +information pertaining to the registers used in this insn. +@end table + +The @code{LOG_LINKS} field of an insn is a chain of @code{insn_list} +expressions. Each of these has two operands: the first is an insn, +and the second is another @code{insn_list} expression (the next one in +the chain). The last @code{insn_list} in the chain has a null pointer +as second operand. The significant thing about the chain is which +insns appear in it (as first operands of @code{insn_list} +expressions). Their order is not significant. + +This list is originally set up by the flow analysis pass; it is a null +pointer until then. Flow only adds links for those data dependencies +which can be used for instruction combination. For each insn, the flow +analysis pass adds a link to insns which store into registers values +that are used for the first time in this insn. The instruction +scheduling pass adds extra links so that every dependence will be +represented. Links represent data dependencies, antidependencies and +output dependencies; the machine mode of the link distinguishes these +three types: antidependencies have mode @code{REG_DEP_ANTI}, output +dependencies have mode @code{REG_DEP_OUTPUT}, and data dependencies have +mode @code{VOIDmode}. + +The @code{REG_NOTES} field of an insn is a chain similar to the +@code{LOG_LINKS} field but it includes @code{expr_list} expressions in +addition to @code{insn_list} expressions. There are several kinds of +register notes, which are distinguished by the machine mode, which in a +register note is really understood as being an @code{enum reg_note}. +The first operand @var{op} of the note is data whose meaning depends on +the kind of note. + +@findex REG_NOTE_KIND +@findex PUT_REG_NOTE_KIND +The macro @code{REG_NOTE_KIND (@var{x})} returns the kind of +register note. Its counterpart, the macro @code{PUT_REG_NOTE_KIND +(@var{x}, @var{newkind})} sets the register note type of @var{x} to be +@var{newkind}. + +Register notes are of three classes: They may say something about an +input to an insn, they may say something about an output of an insn, or +they may create a linkage between two insns. There are also a set +of values that are only used in @code{LOG_LINKS}. + +These register notes annotate inputs to an insn: + +@table @code +@findex REG_DEAD +@item REG_DEAD +The value in @var{op} dies in this insn; that is to say, altering the +value immediately after this insn would not affect the future behavior +of the program. + +It does not follow that the register @var{op} has no useful value after +this insn since @var{op} is not necessarily modified by this insn. +Rather, no subsequent instruction uses the contents of @var{op}. + +@findex REG_UNUSED +@item REG_UNUSED +The register @var{op} being set by this insn will not be used in a +subsequent insn. This differs from a @code{REG_DEAD} note, which +indicates that the value in an input will not be used subsequently. +These two notes are independent; both may be present for the same +register. + +@findex REG_INC +@item REG_INC +The register @var{op} is incremented (or decremented; at this level +there is no distinction) by an embedded side effect inside this insn. +This means it appears in a @code{post_inc}, @code{pre_inc}, +@code{post_dec} or @code{pre_dec} expression. + +@findex REG_NONNEG +@item REG_NONNEG +The register @var{op} is known to have a nonnegative value when this +insn is reached. This is used so that decrement and branch until zero +instructions, such as the m68k dbra, can be matched. + +The @code{REG_NONNEG} note is added to insns only if the machine +description has a @samp{decrement_and_branch_until_zero} pattern. + +@findex REG_NO_CONFLICT +@item REG_NO_CONFLICT +This insn does not cause a conflict between @var{op} and the item +being set by this insn even though it might appear that it does. +In other words, if the destination register and @var{op} could +otherwise be assigned the same register, this insn does not +prevent that assignment. + +Insns with this note are usually part of a block that begins with a +@code{clobber} insn specifying a multi-word pseudo register (which will +be the output of the block), a group of insns that each set one word of +the value and have the @code{REG_NO_CONFLICT} note attached, and a final +insn that copies the output to itself with an attached @code{REG_EQUAL} +note giving the expression being computed. This block is encapsulated +with @code{REG_LIBCALL} and @code{REG_RETVAL} notes on the first and +last insns, respectively. + +@findex REG_LABEL +@item REG_LABEL +This insn uses @var{op}, a @code{code_label} or a @code{note} of type +@code{NOTE_INSN_DELETED_LABEL}, but is not a +@code{jump_insn}, or it is a @code{jump_insn} that required the label to +be held in a register. The presence of this note allows jump +optimization to be aware that @var{op} is, in fact, being used, and flow +optimization to build an accurate flow graph. + +@findex REG_CROSSING_JUMP +@item REG_CROSSING_JUMP +This insn is an branching instruction (either an unconditional jump or +an indirect jump) which crosses between hot and cold sections, which +could potentially be very far apart in the executable. The presence +of this note indicates to other optimizations that this this branching +instruction should not be ``collapsed'' into a simpler branching +construct. It is used when the optimization to partition basic blocks +into hot and cold sections is turned on. + +@findex REG_SETJMP +@item REG_SETJMP +Appears attached to each @code{CALL_INSN} to @code{setjmp} or a +related function. +@end table + +The following notes describe attributes of outputs of an insn: + +@table @code +@findex REG_EQUIV +@findex REG_EQUAL +@item REG_EQUIV +@itemx REG_EQUAL +This note is only valid on an insn that sets only one register and +indicates that that register will be equal to @var{op} at run time; the +scope of this equivalence differs between the two types of notes. The +value which the insn explicitly copies into the register may look +different from @var{op}, but they will be equal at run time. If the +output of the single @code{set} is a @code{strict_low_part} expression, +the note refers to the register that is contained in @code{SUBREG_REG} +of the @code{subreg} expression. + +For @code{REG_EQUIV}, the register is equivalent to @var{op} throughout +the entire function, and could validly be replaced in all its +occurrences by @var{op}. (``Validly'' here refers to the data flow of +the program; simple replacement may make some insns invalid.) For +example, when a constant is loaded into a register that is never +assigned any other value, this kind of note is used. + +When a parameter is copied into a pseudo-register at entry to a function, +a note of this kind records that the register is equivalent to the stack +slot where the parameter was passed. Although in this case the register +may be set by other insns, it is still valid to replace the register +by the stack slot throughout the function. + +A @code{REG_EQUIV} note is also used on an instruction which copies a +register parameter into a pseudo-register at entry to a function, if +there is a stack slot where that parameter could be stored. Although +other insns may set the pseudo-register, it is valid for the compiler to +replace the pseudo-register by stack slot throughout the function, +provided the compiler ensures that the stack slot is properly +initialized by making the replacement in the initial copy instruction as +well. This is used on machines for which the calling convention +allocates stack space for register parameters. See +@code{REG_PARM_STACK_SPACE} in @ref{Stack Arguments}. + +In the case of @code{REG_EQUAL}, the register that is set by this insn +will be equal to @var{op} at run time at the end of this insn but not +necessarily elsewhere in the function. In this case, @var{op} +is typically an arithmetic expression. For example, when a sequence of +insns such as a library call is used to perform an arithmetic operation, +this kind of note is attached to the insn that produces or copies the +final value. + +These two notes are used in different ways by the compiler passes. +@code{REG_EQUAL} is used by passes prior to register allocation (such as +common subexpression elimination and loop optimization) to tell them how +to think of that value. @code{REG_EQUIV} notes are used by register +allocation to indicate that there is an available substitute expression +(either a constant or a @code{mem} expression for the location of a +parameter on the stack) that may be used in place of a register if +insufficient registers are available. + +Except for stack homes for parameters, which are indicated by a +@code{REG_EQUIV} note and are not useful to the early optimization +passes and pseudo registers that are equivalent to a memory location +throughout their entire life, which is not detected until later in +the compilation, all equivalences are initially indicated by an attached +@code{REG_EQUAL} note. In the early stages of register allocation, a +@code{REG_EQUAL} note is changed into a @code{REG_EQUIV} note if +@var{op} is a constant and the insn represents the only set of its +destination register. + +Thus, compiler passes prior to register allocation need only check for +@code{REG_EQUAL} notes and passes subsequent to register allocation +need only check for @code{REG_EQUIV} notes. +@end table + +These notes describe linkages between insns. They occur in pairs: one +insn has one of a pair of notes that points to a second insn, which has +the inverse note pointing back to the first insn. + +@table @code +@findex REG_RETVAL +@item REG_RETVAL +This insn copies the value of a multi-insn sequence (for example, a +library call), and @var{op} is the first insn of the sequence (for a +library call, the first insn that was generated to set up the arguments +for the library call). + +Loop optimization uses this note to treat such a sequence as a single +operation for code motion purposes and flow analysis uses this note to +delete such sequences whose results are dead. + +A @code{REG_EQUAL} note will also usually be attached to this insn to +provide the expression being computed by the sequence. + +These notes will be deleted after reload, since they are no longer +accurate or useful. + +@findex REG_LIBCALL +@item REG_LIBCALL +This is the inverse of @code{REG_RETVAL}: it is placed on the first +insn of a multi-insn sequence, and it points to the last one. + +These notes are deleted after reload, since they are no longer useful or +accurate. + +@findex REG_CC_SETTER +@findex REG_CC_USER +@item REG_CC_SETTER +@itemx REG_CC_USER +On machines that use @code{cc0}, the insns which set and use @code{cc0} +set and use @code{cc0} are adjacent. However, when branch delay slot +filling is done, this may no longer be true. In this case a +@code{REG_CC_USER} note will be placed on the insn setting @code{cc0} to +point to the insn using @code{cc0} and a @code{REG_CC_SETTER} note will +be placed on the insn using @code{cc0} to point to the insn setting +@code{cc0}. +@end table + +These values are only used in the @code{LOG_LINKS} field, and indicate +the type of dependency that each link represents. Links which indicate +a data dependence (a read after write dependence) do not use any code, +they simply have mode @code{VOIDmode}, and are printed without any +descriptive text. + +@table @code +@findex REG_DEP_ANTI +@item REG_DEP_ANTI +This indicates an anti dependence (a write after read dependence). + +@findex REG_DEP_OUTPUT +@item REG_DEP_OUTPUT +This indicates an output dependence (a write after write dependence). +@end table + +These notes describe information gathered from gcov profile data. They +are stored in the @code{REG_NOTES} field of an insn as an +@code{expr_list}. + +@table @code +@findex REG_BR_PROB +@item REG_BR_PROB +This is used to specify the ratio of branches to non-branches of a +branch insn according to the profile data. The value is stored as a +value between 0 and REG_BR_PROB_BASE; larger values indicate a higher +probability that the branch will be taken. + +@findex REG_BR_PRED +@item REG_BR_PRED +These notes are found in JUMP insns after delayed branch scheduling +has taken place. They indicate both the direction and the likelihood +of the JUMP@. The format is a bitmask of ATTR_FLAG_* values. + +@findex REG_FRAME_RELATED_EXPR +@item REG_FRAME_RELATED_EXPR +This is used on an RTX_FRAME_RELATED_P insn wherein the attached expression +is used in place of the actual insn pattern. This is done in cases where +the pattern is either complex or misleading. +@end table + +For convenience, the machine mode in an @code{insn_list} or +@code{expr_list} is printed using these symbolic codes in debugging dumps. + +@findex insn_list +@findex expr_list +The only difference between the expression codes @code{insn_list} and +@code{expr_list} is that the first operand of an @code{insn_list} is +assumed to be an insn and is printed in debugging dumps as the insn's +unique id; the first operand of an @code{expr_list} is printed in the +ordinary way as an expression. + +@node Calls +@section RTL Representation of Function-Call Insns +@cindex calling functions in RTL +@cindex RTL function-call insns +@cindex function-call insns + +Insns that call subroutines have the RTL expression code @code{call_insn}. +These insns must satisfy special rules, and their bodies must use a special +RTL expression code, @code{call}. + +@cindex @code{call} usage +A @code{call} expression has two operands, as follows: + +@smallexample +(call (mem:@var{fm} @var{addr}) @var{nbytes}) +@end smallexample + +@noindent +Here @var{nbytes} is an operand that represents the number of bytes of +argument data being passed to the subroutine, @var{fm} is a machine mode +(which must equal as the definition of the @code{FUNCTION_MODE} macro in +the machine description) and @var{addr} represents the address of the +subroutine. + +For a subroutine that returns no value, the @code{call} expression as +shown above is the entire body of the insn, except that the insn might +also contain @code{use} or @code{clobber} expressions. + +@cindex @code{BLKmode}, and function return values +For a subroutine that returns a value whose mode is not @code{BLKmode}, +the value is returned in a hard register. If this register's number is +@var{r}, then the body of the call insn looks like this: + +@smallexample +(set (reg:@var{m} @var{r}) + (call (mem:@var{fm} @var{addr}) @var{nbytes})) +@end smallexample + +@noindent +This RTL expression makes it clear (to the optimizer passes) that the +appropriate register receives a useful value in this insn. + +When a subroutine returns a @code{BLKmode} value, it is handled by +passing to the subroutine the address of a place to store the value. +So the call insn itself does not ``return'' any value, and it has the +same RTL form as a call that returns nothing. + +On some machines, the call instruction itself clobbers some register, +for example to contain the return address. @code{call_insn} insns +on these machines should have a body which is a @code{parallel} +that contains both the @code{call} expression and @code{clobber} +expressions that indicate which registers are destroyed. Similarly, +if the call instruction requires some register other than the stack +pointer that is not explicitly mentioned in its RTL, a @code{use} +subexpression should mention that register. + +Functions that are called are assumed to modify all registers listed in +the configuration macro @code{CALL_USED_REGISTERS} (@pxref{Register +Basics}) and, with the exception of @code{const} functions and library +calls, to modify all of memory. + +Insns containing just @code{use} expressions directly precede the +@code{call_insn} insn to indicate which registers contain inputs to the +function. Similarly, if registers other than those in +@code{CALL_USED_REGISTERS} are clobbered by the called function, insns +containing a single @code{clobber} follow immediately after the call to +indicate which registers. + +@node Sharing +@section Structure Sharing Assumptions +@cindex sharing of RTL components +@cindex RTL structure sharing assumptions + +The compiler assumes that certain kinds of RTL expressions are unique; +there do not exist two distinct objects representing the same value. +In other cases, it makes an opposite assumption: that no RTL expression +object of a certain kind appears in more than one place in the +containing structure. + +These assumptions refer to a single function; except for the RTL +objects that describe global variables and external functions, +and a few standard objects such as small integer constants, +no RTL objects are common to two functions. + +@itemize @bullet +@cindex @code{reg}, RTL sharing +@item +Each pseudo-register has only a single @code{reg} object to represent it, +and therefore only a single machine mode. + +@cindex symbolic label +@cindex @code{symbol_ref}, RTL sharing +@item +For any symbolic label, there is only one @code{symbol_ref} object +referring to it. + +@cindex @code{const_int}, RTL sharing +@item +All @code{const_int} expressions with equal values are shared. + +@cindex @code{pc}, RTL sharing +@item +There is only one @code{pc} expression. + +@cindex @code{cc0}, RTL sharing +@item +There is only one @code{cc0} expression. + +@cindex @code{const_double}, RTL sharing +@item +There is only one @code{const_double} expression with value 0 for +each floating point mode. Likewise for values 1 and 2. + +@cindex @code{const_vector}, RTL sharing +@item +There is only one @code{const_vector} expression with value 0 for +each vector mode, be it an integer or a double constant vector. + +@cindex @code{label_ref}, RTL sharing +@cindex @code{scratch}, RTL sharing +@item +No @code{label_ref} or @code{scratch} appears in more than one place in +the RTL structure; in other words, it is safe to do a tree-walk of all +the insns in the function and assume that each time a @code{label_ref} +or @code{scratch} is seen it is distinct from all others that are seen. + +@cindex @code{mem}, RTL sharing +@item +Only one @code{mem} object is normally created for each static +variable or stack slot, so these objects are frequently shared in all +the places they appear. However, separate but equal objects for these +variables are occasionally made. + +@cindex @code{asm_operands}, RTL sharing +@item +When a single @code{asm} statement has multiple output operands, a +distinct @code{asm_operands} expression is made for each output operand. +However, these all share the vector which contains the sequence of input +operands. This sharing is used later on to test whether two +@code{asm_operands} expressions come from the same statement, so all +optimizations must carefully preserve the sharing if they copy the +vector at all. + +@item +No RTL object appears in more than one place in the RTL structure +except as described above. Many passes of the compiler rely on this +by assuming that they can modify RTL objects in place without unwanted +side-effects on other insns. + +@findex unshare_all_rtl +@item +During initial RTL generation, shared structure is freely introduced. +After all the RTL for a function has been generated, all shared +structure is copied by @code{unshare_all_rtl} in @file{emit-rtl.c}, +after which the above rules are guaranteed to be followed. + +@findex copy_rtx_if_shared +@item +During the combiner pass, shared structure within an insn can exist +temporarily. However, the shared structure is copied before the +combiner is finished with the insn. This is done by calling +@code{copy_rtx_if_shared}, which is a subroutine of +@code{unshare_all_rtl}. +@end itemize + +@node Reading RTL +@section Reading RTL + +To read an RTL object from a file, call @code{read_rtx}. It takes one +argument, a stdio stream, and returns a single RTL object. This routine +is defined in @file{read-rtl.c}. It is not available in the compiler +itself, only the various programs that generate the compiler back end +from the machine description. + +People frequently have the idea of using RTL stored as text in a file as +an interface between a language front end and the bulk of GCC@. This +idea is not feasible. + +GCC was designed to use RTL internally only. Correct RTL for a given +program is very dependent on the particular target machine. And the RTL +does not contain all the information about the program. + +The proper way to interface GCC to a new language front end is with +the ``tree'' data structure, described in the files @file{tree.h} and +@file{tree.def}. The documentation for this structure (@pxref{Trees}) +is incomplete. diff --git a/gcc-4.2.1-5666.3/gcc/doc/service.texi b/gcc-4.2.1-5666.3/gcc/doc/service.texi new file mode 100644 index 000000000..4cc2b7088 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/service.texi @@ -0,0 +1,28 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2002 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Service +@chapter How To Get Help with GCC + +If you need help installing, using or changing GCC, there are two +ways to find it: + +@itemize @bullet +@item +Send a message to a suitable network mailing list. First try +@email{gcc-help@@gcc.gnu.org} (for help installing or using GCC), and if +that brings no response, try @email{gcc@@gcc.gnu.org}. For help +changing GCC, ask @email{gcc@@gcc.gnu.org}. If you think you have found +a bug in GCC, please report it following the instructions at +@pxref{Bug Reporting}. + +@item +Look in the service directory for someone who might help you for a fee. +The service directory is found at +@uref{http://www.gnu.org/prep/service.html}. +@end itemize + +For further information, see +@uref{http://gcc.gnu.org/faq.html#support}. diff --git a/gcc-4.2.1-5666.3/gcc/doc/sourcebuild.texi b/gcc-4.2.1-5666.3/gcc/doc/sourcebuild.texi new file mode 100644 index 000000000..2db9d10f7 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/sourcebuild.texi @@ -0,0 +1,1524 @@ +@c Copyright (C) 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Source Tree +@chapter Source Tree Structure and Build System + +This chapter describes the structure of the GCC source tree, and how +GCC is built. The user documentation for building and installing GCC +is in a separate manual (@uref{http://gcc.gnu.org/install/}), with +which it is presumed that you are familiar. + +@menu +* Configure Terms:: Configuration terminology and history. +* Top Level:: The top level source directory. +* gcc Directory:: The @file{gcc} subdirectory. +* Testsuites:: The GCC testsuites. +@end menu + +@include configterms.texi + +@node Top Level +@section Top Level Source Directory + +The top level source directory in a GCC distribution contains several +files and directories that are shared with other software +distributions such as that of GNU Binutils. It also contains several +subdirectories that contain parts of GCC and its runtime libraries: + +@table @file +@item boehm-gc +The Boehm conservative garbage collector, used as part of the Java +runtime library. + +@item contrib +Contributed scripts that may be found useful in conjunction with GCC@. +One of these, @file{contrib/texi2pod.pl}, is used to generate man +pages from Texinfo manuals as part of the GCC build process. + +@item fastjar +An implementation of the @command{jar} command, used with the Java +front end. + +@item gcc +The main sources of GCC itself (except for runtime libraries), +including optimizers, support for different target architectures, +language front ends, and testsuites. @xref{gcc Directory, , The +@file{gcc} Subdirectory}, for details. + +@item include +Headers for the @code{libiberty} library. + +@item libada +The Ada runtime library. + +@item libcpp +The C preprocessor library. + +@item libgfortran +The Fortran runtime library. + +@item libffi +The @code{libffi} library, used as part of the Java runtime library. + +@item libiberty +The @code{libiberty} library, used for portability and for some +generally useful data structures and algorithms. @xref{Top, , +Introduction, libiberty, @sc{gnu} libiberty}, for more information +about this library. + +@item libjava +The Java runtime library. + +@item libmudflap +The @code{libmudflap} library, used for instrumenting pointer and array +dereferencing operations. + +@item libobjc +The Objective-C and Objective-C++ runtime library. + +@item libstdc++-v3 +The C++ runtime library. + +@item maintainer-scripts +Scripts used by the @code{gccadmin} account on @code{gcc.gnu.org}. + +@item zlib +The @code{zlib} compression library, used by the Java front end and as +part of the Java runtime library. +@end table + +The build system in the top level directory, including how recursion +into subdirectories works and how building runtime libraries for +multilibs is handled, is documented in a separate manual, included +with GNU Binutils. @xref{Top, , GNU configure and build system, +configure, The GNU configure and build system}, for details. + +@node gcc Directory +@section The @file{gcc} Subdirectory + +The @file{gcc} directory contains many files that are part of the C +sources of GCC, other files used as part of the configuration and +build process, and subdirectories including documentation and a +testsuite. The files that are sources of GCC are documented in a +separate chapter. @xref{Passes, , Passes and Files of the Compiler}. + +@menu +* Subdirectories:: Subdirectories of @file{gcc}. +* Configuration:: The configuration process, and the files it uses. +* Build:: The build system in the @file{gcc} directory. +* Makefile:: Targets in @file{gcc/Makefile}. +* Library Files:: Library source files and headers under @file{gcc/}. +* Headers:: Headers installed by GCC. +* Documentation:: Building documentation in GCC. +* Front End:: Anatomy of a language front end. +* Back End:: Anatomy of a target back end. +@end menu + +@node Subdirectories +@subsection Subdirectories of @file{gcc} + +The @file{gcc} directory contains the following subdirectories: + +@table @file +@item @var{language} +Subdirectories for various languages. Directories containing a file +@file{config-lang.in} are language subdirectories. The contents of +the subdirectories @file{cp} (for C++), @file{objc} (for Objective-C) +and @file{objcp} (for Objective-C++) are documented in this manual +(@pxref{Passes, , Passes and Files of the Compiler}); those for other +languages are not. @xref{Front End, , Anatomy of a Language Front End}, +for details of the files in these directories. + +@item config +Configuration files for supported architectures and operating +systems. @xref{Back End, , Anatomy of a Target Back End}, for +details of the files in this directory. + +@item doc +Texinfo documentation for GCC, together with automatically generated +man pages and support for converting the installation manual to +HTML@. @xref{Documentation}. + +@item fixinc +The support for fixing system headers to work with GCC@. See +@file{fixinc/README} for more information. The headers fixed by this +mechanism are installed in @file{@var{libsubdir}/include}. Along with +those headers, @file{README-fixinc} is also installed, as +@file{@var{libsubdir}/include/README}. + +@item ginclude +System headers installed by GCC, mainly those required by the C +standard of freestanding implementations. @xref{Headers, , Headers +Installed by GCC}, for details of when these and other headers are +installed. + +@item intl +GNU @code{libintl}, from GNU @code{gettext}, for systems which do not +include it in libc. Properly, this directory should be at top level, +parallel to the @file{gcc} directory. + +@item po +Message catalogs with translations of messages produced by GCC into +various languages, @file{@var{language}.po}. This directory also +contains @file{gcc.pot}, the template for these message catalogues, +@file{exgettext}, a wrapper around @command{gettext} to extract the +messages from the GCC sources and create @file{gcc.pot}, which is run +by @samp{make gcc.pot}, and @file{EXCLUDES}, a list of files from +which messages should not be extracted. + +@item testsuite +The GCC testsuites (except for those for runtime libraries). +@xref{Testsuites}. +@end table + +@node Configuration +@subsection Configuration in the @file{gcc} Directory + +The @file{gcc} directory is configured with an Autoconf-generated +script @file{configure}. The @file{configure} script is generated +from @file{configure.ac} and @file{aclocal.m4}. From the files +@file{configure.ac} and @file{acconfig.h}, Autoheader generates the +file @file{config.in}. The file @file{cstamp-h.in} is used as a +timestamp. + +@menu +* Config Fragments:: Scripts used by @file{configure}. +* System Config:: The @file{config.build}, @file{config.host}, and + @file{config.gcc} files. +* Configuration Files:: Files created by running @file{configure}. +@end menu + +@node Config Fragments +@subsubsection Scripts Used by @file{configure} + +@file{configure} uses some other scripts to help in its work: + +@itemize @bullet +@item The standard GNU @file{config.sub} and @file{config.guess} +files, kept in the top level directory, are used. FIXME: when is the +@file{config.guess} file in the @file{gcc} directory (that just calls +the top level one) used? + +@item The file @file{config.gcc} is used to handle configuration +specific to the particular target machine. The file +@file{config.build} is used to handle configuration specific to the +particular build machine. The file @file{config.host} is used to handle +configuration specific to the particular host machine. (In general, +these should only be used for features that cannot reasonably be tested in +Autoconf feature tests.) +@xref{System Config, , The @file{config.build}; @file{config.host}; +and @file{config.gcc} Files}, for details of the contents of these files. + +@item Each language subdirectory has a file +@file{@var{language}/config-lang.in} that is used for +front-end-specific configuration. @xref{Front End Config, , The Front +End @file{config-lang.in} File}, for details of this file. + +@item A helper script @file{configure.frag} is used as part of +creating the output of @file{configure}. +@end itemize + +@node System Config +@subsubsection The @file{config.build}; @file{config.host}; and @file{config.gcc} Files + +The @file{config.build} file contains specific rules for particular systems +which GCC is built on. This should be used as rarely as possible, as the +behavior of the build system can always be detected by autoconf. + +The @file{config.host} file contains specific rules for particular systems +which GCC will run on. This is rarely needed. + +The @file{config.gcc} file contains specific rules for particular systems +which GCC will generate code for. This is usually needed. + +Each file has a list of the shell variables it sets, with descriptions, at the +top of the file. + +FIXME: document the contents of these files, and what variables should +be set to control build, host and target configuration. + +@include configfiles.texi + +@node Build +@subsection Build System in the @file{gcc} Directory + +FIXME: describe the build system, including what is built in what +stages. Also list the various source files that are used in the build +process but aren't source files of GCC itself and so aren't documented +below (@pxref{Passes}). + +@include makefile.texi + +@node Library Files +@subsection Library Source Files and Headers under the @file{gcc} Directory + +FIXME: list here, with explanation, all the C source files and headers +under the @file{gcc} directory that aren't built into the GCC +executable but rather are part of runtime libraries and object files, +such as @file{crtstuff.c} and @file{unwind-dw2.c}. @xref{Headers, , +Headers Installed by GCC}, for more information about the +@file{ginclude} directory. + +@node Headers +@subsection Headers Installed by GCC + +In general, GCC expects the system C library to provide most of the +headers to be used with it. However, GCC will fix those headers if +necessary to make them work with GCC, and will install some headers +required of freestanding implementations. These headers are installed +in @file{@var{libsubdir}/include}. Headers for non-C runtime +libraries are also installed by GCC; these are not documented here. +(FIXME: document them somewhere.) + +Several of the headers GCC installs are in the @file{ginclude} +directory. These headers, @file{iso646.h}, +@file{stdarg.h}, @file{stdbool.h}, and @file{stddef.h}, +are installed in @file{@var{libsubdir}/include}, +unless the target Makefile fragment (@pxref{Target Fragment}) +overrides this by setting @code{USER_H}. + +In addition to these headers and those generated by fixing system +headers to work with GCC, some other headers may also be installed in +@file{@var{libsubdir}/include}. @file{config.gcc} may set +@code{extra_headers}; this specifies additional headers under +@file{config} to be installed on some systems. + +GCC installs its own version of @code{<float.h>}, from @file{ginclude/float.h}. +This is done to cope with command-line options that change the +representation of floating point numbers. + +GCC also installs its own version of @code{<limits.h>}; this is generated +from @file{glimits.h}, together with @file{limitx.h} and +@file{limity.h} if the system also has its own version of +@code{<limits.h>}. (GCC provides its own header because it is +required of ISO C freestanding implementations, but needs to include +the system header from its own header as well because other standards +such as POSIX specify additional values to be defined in +@code{<limits.h>}.) The system's @code{<limits.h>} header is used via +@file{@var{libsubdir}/include/syslimits.h}, which is copied from +@file{gsyslimits.h} if it does not need fixing to work with GCC; if it +needs fixing, @file{syslimits.h} is the fixed copy. + +@node Documentation +@subsection Building Documentation + +The main GCC documentation is in the form of manuals in Texinfo +format. These are installed in Info format; DVI versions may be +generated by @samp{make dvi}, PDF versions by @samp{make pdf}, and +HTML versions by @command{make html}. In addition, some man pages are +generated from the Texinfo manuals, there are some other text files +with miscellaneous documentation, and runtime libraries have their own +documentation outside the @file{gcc} directory. FIXME: document the +documentation for runtime libraries somewhere. + +@menu +* Texinfo Manuals:: GCC manuals in Texinfo format. +* Man Page Generation:: Generating man pages from Texinfo manuals. +* Miscellaneous Docs:: Miscellaneous text files with documentation. +@end menu + +@node Texinfo Manuals +@subsubsection Texinfo Manuals + +The manuals for GCC as a whole, and the C and C++ front ends, are in +files @file{doc/*.texi}. Other front ends have their own manuals in +files @file{@var{language}/*.texi}. Common files +@file{doc/include/*.texi} are provided which may be included in +multiple manuals; the following files are in @file{doc/include}: + +@table @file +@item fdl.texi +The GNU Free Documentation License. +@item funding.texi +The section ``Funding Free Software''. +@item gcc-common.texi +Common definitions for manuals. +@item gpl.texi +The GNU General Public License. +@item texinfo.tex +A copy of @file{texinfo.tex} known to work with the GCC manuals. +@end table + +DVI-formatted manuals are generated by @samp{make dvi}, which uses +@command{texi2dvi} (via the Makefile macro @code{$(TEXI2DVI)}). +PDF-formatted manuals are generated by @samp{make pdf}, which uses +@command{texi2pdf} (via the Makefile macro @code{$(TEXI2PDF)}). HTML +formatted manuals are generated by @command{make html}. Info +manuals are generated by @samp{make info} (which is run as part of +a bootstrap); this generates the manuals in the source directory, +using @command{makeinfo} via the Makefile macro @code{$(MAKEINFO)}, +and they are included in release distributions. + +Manuals are also provided on the GCC web site, in both HTML and +PostScript forms. This is done via the script +@file{maintainer-scripts/update_web_docs}. Each manual to be +provided online must be listed in the definition of @code{MANUALS} in +that file; a file @file{@var{name}.texi} must only appear once in the +source tree, and the output manual must have the same name as the +source file. (However, other Texinfo files, included in manuals but +not themselves the root files of manuals, may have names that appear +more than once in the source tree.) The manual file +@file{@var{name}.texi} should only include other files in its own +directory or in @file{doc/include}. HTML manuals will be generated by +@samp{makeinfo --html}, PostScript manuals by @command{texi2dvi} +and @command{dvips}, and PDF manuals by @command{texi2pdf}. +All Texinfo files that are parts of manuals must +be checked into CVS, even if they are generated files, for the +generation of online manuals to work. + +The installation manual, @file{doc/install.texi}, is also provided on +the GCC web site. The HTML version is generated by the script +@file{doc/install.texi2html}. + +@node Man Page Generation +@subsubsection Man Page Generation + +Because of user demand, in addition to full Texinfo manuals, man pages +are provided which contain extracts from those manuals. These man +pages are generated from the Texinfo manuals using +@file{contrib/texi2pod.pl} and @command{pod2man}. (The man page for +@command{g++}, @file{cp/g++.1}, just contains a @samp{.so} reference +to @file{gcc.1}, but all the other man pages are generated from +Texinfo manuals.) + +Because many systems may not have the necessary tools installed to +generate the man pages, they are only generated if the +@file{configure} script detects that recent enough tools are +installed, and the Makefiles allow generating man pages to fail +without aborting the build. Man pages are also included in release +distributions. They are generated in the source directory. + +Magic comments in Texinfo files starting @samp{@@c man} control what +parts of a Texinfo file go into a man page. Only a subset of Texinfo +is supported by @file{texi2pod.pl}, and it may be necessary to add +support for more Texinfo features to this script when generating new +man pages. To improve the man page output, some special Texinfo +macros are provided in @file{doc/include/gcc-common.texi} which +@file{texi2pod.pl} understands: + +@table @code +@item @@gcctabopt +Use in the form @samp{@@table @@gcctabopt} for tables of options, +where for printed output the effect of @samp{@@code} is better than +that of @samp{@@option} but for man page output a different effect is +wanted. +@item @@gccoptlist +Use for summary lists of options in manuals. +@item @@gol +Use at the end of each line inside @samp{@@gccoptlist}. This is +necessary to avoid problems with differences in how the +@samp{@@gccoptlist} macro is handled by different Texinfo formatters. +@end table + +FIXME: describe the @file{texi2pod.pl} input language and magic +comments in more detail. + +@node Miscellaneous Docs +@subsubsection Miscellaneous Documentation + +In addition to the formal documentation that is installed by GCC, +there are several other text files with miscellaneous documentation: + +@table @file +@item ABOUT-GCC-NLS +Notes on GCC's Native Language Support. FIXME: this should be part of +this manual rather than a separate file. +@item ABOUT-NLS +Notes on the Free Translation Project. +@item COPYING +The GNU General Public License. +@item COPYING.LIB +The GNU Lesser General Public License. +@item *ChangeLog* +@itemx */ChangeLog* +Change log files for various parts of GCC@. +@item LANGUAGES +Details of a few changes to the GCC front-end interface. FIXME: the +information in this file should be part of general documentation of +the front-end interface in this manual. +@item ONEWS +Information about new features in old versions of GCC@. (For recent +versions, the information is on the GCC web site.) +@item README.Portability +Information about portability issues when writing code in GCC@. FIXME: +why isn't this part of this manual or of the GCC Coding Conventions? +@item SERVICE +A pointer to the GNU Service Directory. +@end table + +FIXME: document such files in subdirectories, at least @file{config}, +@file{cp}, @file{objc}, @file{testsuite}. + +@node Front End +@subsection Anatomy of a Language Front End + +A front end for a language in GCC has the following parts: + +@itemize @bullet +@item +A directory @file{@var{language}} under @file{gcc} containing source +files for that front end. @xref{Front End Directory, , The Front End +@file{@var{language}} Directory}, for details. +@item +A mention of the language in the list of supported languages in +@file{gcc/doc/install.texi}. +@item +A mention of the name under which the language's runtime library is +recognized by @option{--enable-shared=@var{package}} in the +documentation of that option in @file{gcc/doc/install.texi}. +@item +A mention of any special prerequisites for building the front end in +the documentation of prerequisites in @file{gcc/doc/install.texi}. +@item +Details of contributors to that front end in +@file{gcc/doc/contrib.texi}. If the details are in that front end's +own manual then there should be a link to that manual's list in +@file{contrib.texi}. +@item +Information about support for that language in +@file{gcc/doc/frontends.texi}. +@item +Information about standards for that language, and the front end's +support for them, in @file{gcc/doc/standards.texi}. This may be a +link to such information in the front end's own manual. +@item +Details of source file suffixes for that language and @option{-x +@var{lang}} options supported, in @file{gcc/doc/invoke.texi}. +@item +Entries in @code{default_compilers} in @file{gcc.c} for source file +suffixes for that language. +@item +Preferably testsuites, which may be under @file{gcc/testsuite} or +runtime library directories. FIXME: document somewhere how to write +testsuite harnesses. +@item +Probably a runtime library for the language, outside the @file{gcc} +directory. FIXME: document this further. +@item +Details of the directories of any runtime libraries in +@file{gcc/doc/sourcebuild.texi}. +@end itemize + +If the front end is added to the official GCC CVS repository, the +following are also necessary: + +@itemize @bullet +@item +At least one Bugzilla component for bugs in that front end and runtime +libraries. This category needs to be mentioned in +@file{gcc/gccbug.in}, as well as being added to the Bugzilla database. +@item +Normally, one or more maintainers of that front end listed in +@file{MAINTAINERS}. +@item +Mentions on the GCC web site in @file{index.html} and +@file{frontends.html}, with any relevant links on +@file{readings.html}. (Front ends that are not an official part of +GCC may also be listed on @file{frontends.html}, with relevant links.) +@item +A news item on @file{index.html}, and possibly an announcement on the +@email{gcc-announce@@gcc.gnu.org} mailing list. +@item +The front end's manuals should be mentioned in +@file{maintainer-scripts/update_web_docs} (@pxref{Texinfo Manuals}) +and the online manuals should be linked to from +@file{onlinedocs/index.html}. +@item +Any old releases or CVS repositories of the front end, before its +inclusion in GCC, should be made available on the GCC FTP site +@uref{ftp://gcc.gnu.org/pub/gcc/old-releases/}. +@item +The release and snapshot script @file{maintainer-scripts/gcc_release} +should be updated to generate appropriate tarballs for this front end. +The associated @file{maintainer-scripts/snapshot-README} and +@file{maintainer-scripts/snapshot-index.html} files should be updated +to list the tarballs and diffs for this front end. +@item +If this front end includes its own version files that include the +current date, @file{maintainer-scripts/update_version} should be +updated accordingly. +@item +@file{CVSROOT/modules} in the GCC CVS repository should be updated. +@end itemize + +@menu +* Front End Directory:: The front end @file{@var{language}} directory. +* Front End Config:: The front end @file{config-lang.in} file. +@end menu + +@node Front End Directory +@subsubsection The Front End @file{@var{language}} Directory + +A front end @file{@var{language}} directory contains the source files +of that front end (but not of any runtime libraries, which should be +outside the @file{gcc} directory). This includes documentation, and +possibly some subsidiary programs build alongside the front end. +Certain files are special and other parts of the compiler depend on +their names: + +@table @file +@item config-lang.in +This file is required in all language subdirectories. @xref{Front End +Config, , The Front End @file{config-lang.in} File}, for details of +its contents +@item Make-lang.in +This file is required in all language subdirectories. It contains +targets @code{@var{lang}.@var{hook}} (where @code{@var{lang}} is the +setting of @code{language} in @file{config-lang.in}) for the following +values of @code{@var{hook}}, and any other Makefile rules required to +build those targets (which may if necessary use other Makefiles +specified in @code{outputs} in @file{config-lang.in}, although this is +deprecated). It also adds any testsuite targets that can use the +standard rule in @file{gcc/Makefile.in} to the variable +@code{lang_checks}. + +@table @code +@itemx all.cross +@itemx start.encap +@itemx rest.encap +FIXME: exactly what goes in each of these targets? +@item tags +Build an @command{etags} @file{TAGS} file in the language subdirectory +in the source tree. +@item info +Build info documentation for the front end, in the build directory. +This target is only called by @samp{make bootstrap} if a suitable +version of @command{makeinfo} is available, so does not need to check +for this, and should fail if an error occurs. +@item dvi +Build DVI documentation for the front end, in the build directory. +This should be done using @code{$(TEXI2DVI)}, with appropriate +@option{-I} arguments pointing to directories of included files. +@item pdf +Build PDF documentation for the front end, in the build directory. +This should be done using @code{$(TEXI2PDF)}, with appropriate +@option{-I} arguments pointing to directories of included files. +@item html +Build HTML documentation for the front end, in the build directory. +@item man +Build generated man pages for the front end from Texinfo manuals +(@pxref{Man Page Generation}), in the build directory. This target +is only called if the necessary tools are available, but should ignore +errors so as not to stop the build if errors occur; man pages are +optional and the tools involved may be installed in a broken way. +@item install-common +Install everything that is part of the front end, apart from the +compiler executables listed in @code{compilers} in +@file{config-lang.in}. +@item install-info +Install info documentation for the front end, if it is present in the +source directory. This target should have dependencies on info files +that should be installed. +@item install-man +Install man pages for the front end. This target should ignore +errors. +@item srcextra +Copies its dependencies into the source directory. This generally should +be used for generated files such as Bison output files which are not +present in CVS, but should be included in any release tarballs. This +target will be executed during a bootstrap if +@samp{--enable-generated-files-in-srcdir} was specified as a +@file{configure} option. +@item srcinfo +@itemx srcman +Copies its dependencies into the source directory. These targets will be +executed during a bootstrap if @samp{--enable-generated-files-in-srcdir} +was specified as a @file{configure} option. +@item uninstall +Uninstall files installed by installing the compiler. This is +currently documented not to be supported, so the hook need not do +anything. +@item mostlyclean +@itemx clean +@itemx distclean +@itemx maintainer-clean +The language parts of the standard GNU +@samp{*clean} targets. @xref{Standard Targets, , Standard Targets for +Users, standards, GNU Coding Standards}, for details of the standard +targets. For GCC, @code{maintainer-clean} should delete +all generated files in the source directory that are not checked into +CVS, but should not delete anything checked into CVS@. +@item stage1 +@itemx stage2 +@itemx stage3 +@itemx stage4 +@itemx stageprofile +@itemx stagefeedback +Move to the stage directory files not included in @code{stagestuff} in +@file{config-lang.in} or otherwise moved by the main @file{Makefile}. +@end table + +@item lang.opt +This file registers the set of switches that the front end accepts on +the command line, and their @option{--help} text. @xref{Options}. +@item lang-specs.h +This file provides entries for @code{default_compilers} in +@file{gcc.c} which override the default of giving an error that a +compiler for that language is not installed. +@item @var{language}-tree.def +This file, which need not exist, defines any language-specific tree +codes. +@end table + +@node Front End Config +@subsubsection The Front End @file{config-lang.in} File + +Each language subdirectory contains a @file{config-lang.in} file. In +addition the main directory contains @file{c-config-lang.in}, which +contains limited information for the C language. This file is a shell +script that may define some variables describing the language: + +@table @code +@item language +This definition must be present, and gives the name of the language +for some purposes such as arguments to @option{--enable-languages}. +@item lang_requires +If defined, this variable lists (space-separated) language front ends +other than C that this front end requires to be enabled (with the +names given being their @code{language} settings). For example, the +Java front end depends on the C++ front end, so sets +@samp{lang_requires=c++}. +@item subdir_requires +If defined, this variable lists (space-separated) front end directories +other than C that this front end requires to be present. For example, +the Objective-C++ front end uses source files from the C++ and +Objective-C front ends, so sets @samp{subdir_requires="cp objc"}. +@item target_libs +If defined, this variable lists (space-separated) targets in the top +level @file{Makefile} to build the runtime libraries for this +language, such as @code{target-libobjc}. +@item lang_dirs +If defined, this variable lists (space-separated) top level +directories (parallel to @file{gcc}), apart from the runtime libraries, +that should not be configured if this front end is not built. +@item build_by_default +If defined to @samp{no}, this language front end is not built unless +enabled in a @option{--enable-languages} argument. Otherwise, front +ends are built by default, subject to any special logic in +@file{configure.ac} (as is present to disable the Ada front end if the +Ada compiler is not already installed). +@item boot_language +If defined to @samp{yes}, this front end is built in stage 1 of the +bootstrap. This is only relevant to front ends written in their own +languages. +@item compilers +If defined, a space-separated list of compiler executables that will +be run by the driver. The names here will each end +with @samp{\$(exeext)}. +@item stagestuff +If defined, a space-separated list of files that should be moved to +the @file{stage@var{n}} directories in each stage of bootstrap. +@item outputs +If defined, a space-separated list of files that should be generated +by @file{configure} substituting values in them. This mechanism can +be used to create a file @file{@var{language}/Makefile} from +@file{@var{language}/Makefile.in}, but this is deprecated, building +everything from the single @file{gcc/Makefile} is preferred. +@item gtfiles +If defined, a space-separated list of files that should be scanned by +gengtype.c to generate the garbage collection tables and routines for +this language. This excludes the files that are common to all front +ends. @xref{Type Information}. +@item need_gmp +If defined to @samp{yes}, this frontend requires the GMP library. +Enables configure tests for GMP, which set @code{GMPLIBS} and +@code{GMPINC} appropriately. + +@end table + +@node Back End +@subsection Anatomy of a Target Back End + +A back end for a target architecture in GCC has the following parts: + +@itemize @bullet +@item +A directory @file{@var{machine}} under @file{gcc/config}, containing a +machine description @file{@var{machine}.md} file (@pxref{Machine Desc, +, Machine Descriptions}), header files @file{@var{machine}.h} and +@file{@var{machine}-protos.h} and a source file @file{@var{machine}.c} +(@pxref{Target Macros, , Target Description Macros and Functions}), +possibly a target Makefile fragment @file{t-@var{machine}} +(@pxref{Target Fragment, , The Target Makefile Fragment}), and maybe +some other files. The names of these files may be changed from the +defaults given by explicit specifications in @file{config.gcc}. +@item +If necessary, a file @file{@var{machine}-modes.def} in the +@file{@var{machine}} directory, containing additional machine modes to +represent condition codes. @xref{Condition Code}, for further details. +@item +An optional @file{@var{machine}.opt} file in the @file{@var{machine}} +directory, containing a list of target-specific options. You can also +add other option files using the @code{extra_options} variable in +@file{config.gcc}. @xref{Options}. +@item +Entries in @file{config.gcc} (@pxref{System Config, , The +@file{config.gcc} File}) for the systems with this target +architecture. +@item +Documentation in @file{gcc/doc/invoke.texi} for any command-line +options supported by this target (@pxref{Run-time Target, , Run-time +Target Specification}). This means both entries in the summary table +of options and details of the individual options. +@item +Documentation in @file{gcc/doc/extend.texi} for any target-specific +attributes supported (@pxref{Target Attributes, , Defining +target-specific uses of @code{__attribute__}}), including where the +same attribute is already supported on some targets, which are +enumerated in the manual. +@item +Documentation in @file{gcc/doc/extend.texi} for any target-specific +pragmas supported. +@item +Documentation in @file{gcc/doc/extend.texi} of any target-specific +built-in functions supported. +@item +Documentation in @file{gcc/doc/extend.texi} of any target-specific +format checking styles supported. +@item +Documentation in @file{gcc/doc/md.texi} of any target-specific +constraint letters (@pxref{Machine Constraints, , Constraints for +Particular Machines}). +@item +A note in @file{gcc/doc/contrib.texi} under the person or people who +contributed the target support. +@item +Entries in @file{gcc/doc/install.texi} for all target triplets +supported with this target architecture, giving details of any special +notes about installation for this target, or saying that there are no +special notes if there are none. +@item +Possibly other support outside the @file{gcc} directory for runtime +libraries. FIXME: reference docs for this. The libstdc++ porting +manual needs to be installed as info for this to work, or to be a +chapter of this manual. +@end itemize + +If the back end is added to the official GCC CVS repository, the +following are also necessary: + +@itemize @bullet +@item +An entry for the target architecture in @file{readings.html} on the +GCC web site, with any relevant links. +@item +Details of the properties of the back end and target architecture in +@file{backends.html} on the GCC web site. +@item +A news item about the contribution of support for that target +architecture, in @file{index.html} on the GCC web site. +@item +Normally, one or more maintainers of that target listed in +@file{MAINTAINERS}. Some existing architectures may be unmaintained, +but it would be unusual to add support for a target that does not have +a maintainer when support is added. +@end itemize + +@node Testsuites +@section Testsuites + +GCC contains several testsuites to help maintain compiler quality. +Most of the runtime libraries and language front ends in GCC have +testsuites. Currently only the C language testsuites are documented +here; FIXME: document the others. + +@menu +* Test Idioms:: Idioms used in testsuite code. +* Test Directives:: Directives used within DejaGnu tests. +* Ada Tests:: The Ada language testsuites. +* C Tests:: The C language testsuites. +* libgcj Tests:: The Java library testsuites. +* gcov Testing:: Support for testing gcov. +* profopt Testing:: Support for testing profile-directed optimizations. +* compat Testing:: Support for testing binary compatibility. +@end menu + +@node Test Idioms +@subsection Idioms Used in Testsuite Code + +In general, C testcases have a trailing @file{-@var{n}.c}, starting +with @file{-1.c}, in case other testcases with similar names are added +later. If the test is a test of some well-defined feature, it should +have a name referring to that feature such as +@file{@var{feature}-1.c}. If it does not test a well-defined feature +but just happens to exercise a bug somewhere in the compiler, and a +bug report has been filed for this bug in the GCC bug database, +@file{pr@var{bug-number}-1.c} is the appropriate form of name. +Otherwise (for miscellaneous bugs not filed in the GCC bug database), +and previously more generally, test cases are named after the date on +which they were added. This allows people to tell at a glance whether +a test failure is because of a recently found bug that has not yet +been fixed, or whether it may be a regression, but does not give any +other information about the bug or where discussion of it may be +found. Some other language testsuites follow similar conventions. + +In the @file{gcc.dg} testsuite, it is often necessary to test that an +error is indeed a hard error and not just a warning---for example, +where it is a constraint violation in the C standard, which must +become an error with @option{-pedantic-errors}. The following idiom, +where the first line shown is line @var{line} of the file and the line +that generates the error, is used for this: + +@smallexample +/* @{ dg-bogus "warning" "warning in place of error" @} */ +/* @{ dg-error "@var{regexp}" "@var{message}" @{ target *-*-* @} @var{line} @} */ +@end smallexample + +It may be necessary to check that an expression is an integer constant +expression and has a certain value. To check that @code{@var{E}} has +value @code{@var{V}}, an idiom similar to the following is used: + +@smallexample +char x[((E) == (V) ? 1 : -1)]; +@end smallexample + +In @file{gcc.dg} tests, @code{__typeof__} is sometimes used to make +assertions about the types of expressions. See, for example, +@file{gcc.dg/c99-condexpr-1.c}. The more subtle uses depend on the +exact rules for the types of conditional expressions in the C +standard; see, for example, @file{gcc.dg/c99-intconst-1.c}. + +It is useful to be able to test that optimizations are being made +properly. This cannot be done in all cases, but it can be done where +the optimization will lead to code being optimized away (for example, +where flow analysis or alias analysis should show that certain code +cannot be called) or to functions not being called because they have +been expanded as built-in functions. Such tests go in +@file{gcc.c-torture/execute}. Where code should be optimized away, a +call to a nonexistent function such as @code{link_failure ()} may be +inserted; a definition + +@smallexample +#ifndef __OPTIMIZE__ +void +link_failure (void) +@{ + abort (); +@} +#endif +@end smallexample + +@noindent +will also be needed so that linking still succeeds when the test is +run without optimization. When all calls to a built-in function +should have been optimized and no calls to the non-built-in version of +the function should remain, that function may be defined as +@code{static} to call @code{abort ()} (although redeclaring a function +as static may not work on all targets). + +All testcases must be portable. Target-specific testcases must have +appropriate code to avoid causing failures on unsupported systems; +unfortunately, the mechanisms for this differ by directory. + +FIXME: discuss non-C testsuites here. + +@node Test Directives +@subsection Directives used within DejaGnu tests + +Test directives appear within comments in a test source file and begin +with @code{dg-}. Some of these are defined within DejaGnu and others +are local to the GCC testsuite. + +The order in which test directives appear in a test can be important: +directives local to GCC sometimes override information used by the +DejaGnu directives, which know nothing about the GCC directives, so the +DejaGnu directives must precede GCC directives. + +Several test directives include selectors which are usually preceded by +the keyword @code{target} or @code{xfail}. A selector is: one or more +target triplets, possibly including wildcard characters; a single +effective-target keyword; or a logical expression. Depending on the +context, the selector specifies whether a test is skipped and reported +as unsupported or is expected to fail. Use @samp{*-*-*} to match any +target. +Effective-target keywords are defined in @file{target-supports.exp} in +the GCC testsuite. + +A selector expression appears within curly braces and uses a single +logical operator: one of @samp{!}, @samp{&&}, or @samp{||}. An +operand is another selector expression, an effective-target keyword, +a single target triplet, or a list of target triplets within quotes or +curly braces. For example: + +@smallexample +@{ target @{ ! "hppa*-*-* ia64*-*-*" @} @} +@{ target @{ powerpc*-*-* && lp64 @} @} +@{ xfail @{ lp64 || vect_no_align @} @} +@end smallexample + +@table @code +@item @{ dg-do @var{do-what-keyword} [@{ target/xfail @var{selector} @}] @} +@var{do-what-keyword} specifies how the test is compiled and whether +it is executed. It is one of: + +@table @code +@item preprocess +Compile with @option{-E} to run only the preprocessor. +@item assemble +Compile with @option{-S} to produce an assembly code file. +@item compile +Compile with @option{-c} to produce a relocatable object file. +@item link +Compile, assemble, and link to produce an executable file. +@item run +Produce and run an executable file, which is expected to return +an exit code of 0. +@end table + +The default is @code{compile}. That can be overridden for a set of +tests by redefining @code{dg-do-what-default} within the @code{.exp} +file for those tests. + +If the directive includes the optional @samp{@{ target @var{selector} @}} +then the test is skipped unless the target system is included in the +list of target triplets or matches the effective-target keyword. + +If the directive includes the optional @samp{@{ xfail @var{selector} @}} +and the selector is met then the test is expected to fail. For +@code{dg-do run}, execution is expected to fail but compilation +is expected to pass. + +@item @{ dg-options @var{options} [@{ target @var{selector} @}] @} +This DejaGnu directive provides a list of compiler options, to be used +if the target system matches @var{selector}, that replace the default +options used for this set of tests. + +@item @{ dg-skip-if @var{comment} @{ @var{selector} @} @{ @var{include-opts} @} @{ @var{exclude-opts} @} @} +Skip the test if the test system is included in @var{selector} and if +each of the options in @var{include-opts} is in the set of options with +which the test would be compiled and if none of the options in +@var{exclude-opts} is in the set of options with which the test would be +compiled. + +Use @samp{"*"} for an empty @var{include-opts} list and @samp{""} for +an empty @var{exclude-opts} list. + +@item @{ dg-xfail-if @var{comment} @{ @var{selector} @} @{ @var{include-opts} @} @{ @var{exclude-opts} @} @} +Expect the test to fail if the conditions (which are the same as for +@code{dg-skip-if}) are met. + +@item @{ dg-require-@var{support} args @} +Skip the test if the target does not provide the required support; +see @file{gcc-dg.exp} in the GCC testsuite for the actual directives. +These directives must appear after any @code{dg-do} directive in the test. +They require at least one argument, which can be an empty string if the +specific procedure does not examine the argument. + +@item @{ dg-require-effective-target @var{keyword} @} +Skip the test if the test target, including current multilib flags, +is not covered by the effective-target keyword. +This directive must appear after any @code{dg-do} directive in the test. + +@item @{ dg-shouldfail @var{comment} @{ @var{selector} @} @{ @var{include-opts} @} @{ @var{exclude-opts} @} @} +Expect the test executable to return a nonzero exit status if the +conditions (which are the same as for @code{dg-skip-if}) are met. + +@item @{ dg-error @var{regexp} [@var{comment} [@{ target/xfail @var{selector} @} [@var{line}] @}]] @} +This DejaGnu directive appears on a source line that is expected to get +an error message, or else specifies the source line associated with the +message. If there is no message for that line or if the text of that +message is not matched by @var{regexp} then the check fails and +@var{comment} is included in the @code{FAIL} message. The check does +not look for the string @samp{"error"} unless it is part of @var{regexp}. + +@item @{ dg-warning @var{regexp} [@var{comment} [@{ target/xfail @var{selector} @} [@var{line}] @}]] @} +This DejaGnu directive appears on a source line that is expected to get +a warning message, or else specifies the source line associated with the +message. If there is no message for that line or if the text of that +message is not matched by @var{regexp} then the check fails and +@var{comment} is included in the @code{FAIL} message. The check does +not look for the string @samp{"warning"} unless it is part of @var{regexp}. + +@item @{ dg-bogus @var{regexp} [@var{comment} [@{ target/xfail @var{selector} @} [@var{line}] @}]] @} +This DejaGnu directive appears on a source line that should not get a +message matching @var{regexp}, or else specifies the source line +associated with the bogus message. It is usually used with @samp{xfail} +to indicate that the message is a known problem for a particular set of +targets. + +@item @{ dg-excess-errors @var{comment} [@{ target/xfail @var{selector} @}] @} +This DejaGnu directive indicates that the test is expected to fail due +to compiler messages that are not handled by @samp{dg-error}, +@samp{dg-warning} or @samp{dg-bogus}. + +@item @{ dg-output @var{regexp} [@{ target/xfail @var{selector} @}] @} +This DejaGnu directive compares @var{regexp} to the combined output +that the test executable writes to @file{stdout} and @file{stderr}. + +@item @{ dg-prune-output @var{regexp} @} +Prune messages matching @var{regexp} from test output. + +@item @{ dg-additional-files "@var{filelist}" @} +Specify additional files, other than source files, that must be copied +to the system where the compiler runs. + +@item @{ dg-additional-sources "@var{filelist}" @} +Specify additional source files to appear in the compile line +following the main test file. + +@item @{ dg-final @{ @var{local-directive} @} @} +This DejaGnu directive is placed within a comment anywhere in the +source file and is processed after the test has been compiled and run. +Multiple @samp{dg-final} commands are processed in the order in which +they appear in the source file. + +The GCC testsuite defines the following directives to be used within +@code{dg-final}. + +@table @code +@item cleanup-coverage-files +Removes coverage data files generated for this test. + +@item cleanup-repo-files +Removes files generated for this test for @option{-frepo}. + +@item cleanup-rtl-dump @var{suffix} +Removes RTL dump files generated for this test. + +@item cleanup-tree-dump @var{suffix} +Removes tree dump files matching @var{suffix} which were generated for +this test. + +@item cleanup-saved-temps +Removes files for the current test which were kept for @option{--save-temps}. + +@item scan-file @var{filename} @var{regexp} [@{ target/xfail @var{selector} @}] +Passes if @var{regexp} matches text in @var{filename}. + +@item scan-file-not @var{filename} @var{regexp} [@{ target/xfail @var{selector} @}] +Passes if @var{regexp} does not match text in @var{filename}. + +@item scan-hidden @var{symbol} [@{ target/xfail @var{selector} @}] +Passes if @var{symbol} is defined as a hidden symbol in the test's +assembly output. + +@item scan-not-hidden @var{symbol} [@{ target/xfail @var{selector} @}] +Passes if @var{symbol} is not defined as a hidden symbol in the test's +assembly output. + +@item scan-assembler-times @var{regex} @var{num} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} is matched exactly @var{num} times in the test's +assembler output. + +@item scan-assembler @var{regex} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} matches text in the test's assembler output. + +@item scan-assembler-not @var{regex} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} does not match text in the test's assembler output. + +@item scan-assembler-dem @var{regex} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} matches text in the test's demangled assembler output. + +@item scan-assembler-dem-not @var{regex} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} does not match text in the test's demangled assembler +output. + +@item scan-tree-dump-times @var{regex} @var{num} @var{suffix} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} is found exactly @var{num} times in the dump file +with suffix @var{suffix}. + +@item scan-tree-dump @var{regex} @var{suffix} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} matches text in the dump file with suffix @var{suffix}. + +@item scan-tree-dump-not @var{regex} @var{suffix} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} does not match text in the dump file with suffix +@var{suffix}. + +@item scan-tree-dump-dem @var{regex} @var{suffix} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} matches demangled text in the dump file with +suffix @var{suffix}. + +@item scan-tree-dump-dem-not @var{regex} @var{suffix} [@{ target/xfail @var{selector} @}] +Passes if @var{regex} does not match demangled text in the dump file with +suffix @var{suffix}. + +@item output-exists [@{ target/xfail @var{selector} @}] +Passes if compiler output file exists. + +@item output-exists-not [@{ target/xfail @var{selector} @}] +Passes if compiler output file does not exist. + +@item run-gcov @var{sourcefile} +Check line counts in @command{gcov} tests. + +@item run-gcov [branches] [calls] @{ @var{opts} @var{sourcefile} @} +Check branch and/or call counts, in addition to line counts, in +@command{gcov} tests. +@end table +@end table + +@node Ada Tests +@subsection Ada Language Testsuites + +The Ada testsuite includes executable tests from the ACATS 2.5 +testsuite, publicly available at +@uref{http://www.adaic.org/compilers/acats/2.5} + +These tests are integrated in the GCC testsuite in the +@file{gcc/testsuite/ada/acats} directory, and +enabled automatically when running @code{make check}, assuming +the Ada language has been enabled when configuring GCC@. + +You can also run the Ada testsuite independently, using +@code{make check-ada}, or run a subset of the tests by specifying which +chapter to run, e.g.: + +@smallexample +$ make check-ada CHAPTERS="c3 c9" +@end smallexample + +The tests are organized by directory, each directory corresponding to +a chapter of the Ada Reference Manual. So for example, c9 corresponds +to chapter 9, which deals with tasking features of the language. + +There is also an extra chapter called @file{gcc} containing a template for +creating new executable tests. + +The tests are run using two @command{sh} scripts: @file{run_acats} and +@file{run_all.sh}. To run the tests using a simulator or a cross +target, see the small +customization section at the top of @file{run_all.sh}. + +These tests are run using the build tree: they can be run without doing +a @code{make install}. + +@node C Tests +@subsection C Language Testsuites + +GCC contains the following C language testsuites, in the +@file{gcc/testsuite} directory: + +@table @file +@item gcc.dg +This contains tests of particular features of the C compiler, using the +more modern @samp{dg} harness. Correctness tests for various compiler +features should go here if possible. + +Magic comments determine whether the file +is preprocessed, compiled, linked or run. In these tests, error and warning +message texts are compared against expected texts or regular expressions +given in comments. These tests are run with the options @samp{-ansi -pedantic} +unless other options are given in the test. Except as noted below they +are not run with multiple optimization options. +@item gcc.dg/compat +This subdirectory contains tests for binary compatibility using +@file{compat.exp}, which in turn uses the language-independent support +(@pxref{compat Testing, , Support for testing binary compatibility}). +@item gcc.dg/cpp +This subdirectory contains tests of the preprocessor. +@item gcc.dg/debug +This subdirectory contains tests for debug formats. Tests in this +subdirectory are run for each debug format that the compiler supports. +@item gcc.dg/format +This subdirectory contains tests of the @option{-Wformat} format +checking. Tests in this directory are run with and without +@option{-DWIDE}. +@item gcc.dg/noncompile +This subdirectory contains tests of code that should not compile and +does not need any special compilation options. They are run with +multiple optimization options, since sometimes invalid code crashes +the compiler with optimization. +@item gcc.dg/special +FIXME: describe this. + +@item gcc.c-torture +This contains particular code fragments which have historically broken easily. +These tests are run with multiple optimization options, so tests for features +which only break at some optimization levels belong here. This also contains +tests to check that certain optimizations occur. It might be worthwhile to +separate the correctness tests cleanly from the code quality tests, but +it hasn't been done yet. + +@item gcc.c-torture/compat +FIXME: describe this. + +This directory should probably not be used for new tests. +@item gcc.c-torture/compile +This testsuite contains test cases that should compile, but do not +need to link or run. These test cases are compiled with several +different combinations of optimization options. All warnings are +disabled for these test cases, so this directory is not suitable if +you wish to test for the presence or absence of compiler warnings. +While special options can be set, and tests disabled on specific +platforms, by the use of @file{.x} files, mostly these test cases +should not contain platform dependencies. FIXME: discuss how defines +such as @code{NO_LABEL_VALUES} and @code{STACK_SIZE} are used. +@item gcc.c-torture/execute +This testsuite contains test cases that should compile, link and run; +otherwise the same comments as for @file{gcc.c-torture/compile} apply. +@item gcc.c-torture/execute/ieee +This contains tests which are specific to IEEE floating point. +@item gcc.c-torture/unsorted +FIXME: describe this. + +This directory should probably not be used for new tests. +@item gcc.c-torture/misc-tests +This directory contains C tests that require special handling. Some +of these tests have individual expect files, and others share +special-purpose expect files: + +@table @file +@item @code{bprob*.c} +Test @option{-fbranch-probabilities} using @file{bprob.exp}, which +in turn uses the generic, language-independent framework +(@pxref{profopt Testing, , Support for testing profile-directed +optimizations}). + +@item @code{dg-*.c} +Test the testsuite itself using @file{dg-test.exp}. + +@item @code{gcov*.c} +Test @command{gcov} output using @file{gcov.exp}, which in turn uses the +language-independent support (@pxref{gcov Testing, , Support for testing gcov}). + +@item @code{i386-pf-*.c} +Test i386-specific support for data prefetch using @file{i386-prefetch.exp}. +@end table + +@end table + +FIXME: merge in @file{testsuite/README.gcc} and discuss the format of +test cases and magic comments more. + +@node libgcj Tests +@subsection The Java library testsuites. + +Runtime tests are executed via @samp{make check} in the +@file{@var{target}/libjava/testsuite} directory in the build +tree. Additional runtime tests can be checked into this testsuite. + +Regression testing of the core packages in libgcj is also covered by the +Mauve testsuite. The @uref{http://sourceware.org/mauve/,,Mauve Project} +develops tests for the Java Class Libraries. These tests are run as part +of libgcj testing by placing the Mauve tree within the libjava testsuite +sources at @file{libjava/testsuite/libjava.mauve/mauve}, or by specifying +the location of that tree when invoking @samp{make}, as in +@samp{make MAUVEDIR=~/mauve check}. + +To detect regressions, a mechanism in @file{mauve.exp} compares the +failures for a test run against the list of expected failures in +@file{libjava/testsuite/libjava.mauve/xfails} from the source hierarchy. +Update this file when adding new failing tests to Mauve, or when fixing +bugs in libgcj that had caused Mauve test failures. + +The @uref{http://sourceware.org/mauve/jacks.html,, +Jacks} project provides a testsuite for Java compilers that can be used +to test changes that affect the GCJ front end. This testsuite is run as +part of Java testing by placing the Jacks tree within the libjava +testsuite sources at @file{libjava/testsuite/libjava.jacks/jacks}. + +We encourage developers to contribute test cases to Mauve and Jacks. + +@node gcov Testing +@subsection Support for testing @command{gcov} + +Language-independent support for testing @command{gcov}, and for checking +that branch profiling produces expected values, is provided by the +expect file @file{gcov.exp}. @command{gcov} tests also rely on procedures +in @file{gcc.dg.exp} to compile and run the test program. A typical +@command{gcov} test contains the following DejaGnu commands within comments: + +@smallexample +@{ dg-options "-fprofile-arcs -ftest-coverage" @} +@{ dg-do run @{ target native @} @} +@{ dg-final @{ run-gcov sourcefile @} @} +@end smallexample + +Checks of @command{gcov} output can include line counts, branch percentages, +and call return percentages. All of these checks are requested via +commands that appear in comments in the test's source file. +Commands to check line counts are processed by default. +Commands to check branch percentages and call return percentages are +processed if the @command{run-gcov} command has arguments @code{branches} +or @code{calls}, respectively. For example, the following specifies +checking both, as well as passing @option{-b} to @command{gcov}: + +@smallexample +@{ dg-final @{ run-gcov branches calls @{ -b sourcefile @} @} @} +@end smallexample + +A line count command appears within a comment on the source line +that is expected to get the specified count and has the form +@code{count(@var{cnt})}. A test should only check line counts for +lines that will get the same count for any architecture. + +Commands to check branch percentages (@code{branch}) and call +return percentages (@code{returns}) are very similar to each other. +A beginning command appears on or before the first of a range of +lines that will report the percentage, and the ending command +follows that range of lines. The beginning command can include a +list of percentages, all of which are expected to be found within +the range. A range is terminated by the next command of the same +kind. A command @code{branch(end)} or @code{returns(end)} marks +the end of a range without starting a new one. For example: + +@smallexample +if (i > 10 && j > i && j < 20) /* @r{branch(27 50 75)} */ + /* @r{branch(end)} */ + foo (i, j); +@end smallexample + +For a call return percentage, the value specified is the +percentage of calls reported to return. For a branch percentage, +the value is either the expected percentage or 100 minus that +value, since the direction of a branch can differ depending on the +target or the optimization level. + +Not all branches and calls need to be checked. A test should not +check for branches that might be optimized away or replaced with +predicated instructions. Don't check for calls inserted by the +compiler or ones that might be inlined or optimized away. + +A single test can check for combinations of line counts, branch +percentages, and call return percentages. The command to check a +line count must appear on the line that will report that count, but +commands to check branch percentages and call return percentages can +bracket the lines that report them. + +@node profopt Testing +@subsection Support for testing profile-directed optimizations + +The file @file{profopt.exp} provides language-independent support for +checking correct execution of a test built with profile-directed +optimization. This testing requires that a test program be built and +executed twice. The first time it is compiled to generate profile +data, and the second time it is compiled to use the data that was +generated during the first execution. The second execution is to +verify that the test produces the expected results. + +To check that the optimization actually generated better code, a +test can be built and run a third time with normal optimizations to +verify that the performance is better with the profile-directed +optimizations. @file{profopt.exp} has the beginnings of this kind +of support. + +@file{profopt.exp} provides generic support for profile-directed +optimizations. Each set of tests that uses it provides information +about a specific optimization: + +@table @code +@item tool +tool being tested, e.g., @command{gcc} + +@item profile_option +options used to generate profile data + +@item feedback_option +options used to optimize using that profile data + +@item prof_ext +suffix of profile data files + +@item PROFOPT_OPTIONS +list of options with which to run each test, similar to the lists for +torture tests +@end table + +@node compat Testing +@subsection Support for testing binary compatibility + +The file @file{compat.exp} provides language-independent support for +binary compatibility testing. It supports testing interoperability of +two compilers that follow the same ABI, or of multiple sets of +compiler options that should not affect binary compatibility. It is +intended to be used for testsuites that complement ABI testsuites. + +A test supported by this framework has three parts, each in a +separate source file: a main program and two pieces that interact +with each other to split up the functionality being tested. + +@table @file +@item @var{testname}_main.@var{suffix} +Contains the main program, which calls a function in file +@file{@var{testname}_x.@var{suffix}}. + +@item @var{testname}_x.@var{suffix} +Contains at least one call to a function in +@file{@var{testname}_y.@var{suffix}}. + +@item @var{testname}_y.@var{suffix} +Shares data with, or gets arguments from, +@file{@var{testname}_x.@var{suffix}}. +@end table + +Within each test, the main program and one functional piece are +compiled by the GCC under test. The other piece can be compiled by +an alternate compiler. If no alternate compiler is specified, +then all three source files are all compiled by the GCC under test. +You can specify pairs of sets of compiler options. The first element +of such a pair specifies options used with the GCC under test, and the +second element of the pair specifies options used with the alternate +compiler. Each test is compiled with each pair of options. + +@file{compat.exp} defines default pairs of compiler options. +These can be overridden by defining the environment variable +@env{COMPAT_OPTIONS} as: + +@smallexample +COMPAT_OPTIONS="[list [list @{@var{tst1}@} @{@var{alt1}@}] + ...[list @{@var{tstn}@} @{@var{altn}@}]]" +@end smallexample + +where @var{tsti} and @var{alti} are lists of options, with @var{tsti} +used by the compiler under test and @var{alti} used by the alternate +compiler. For example, with +@code{[list [list @{-g -O0@} @{-O3@}] [list @{-fpic@} @{-fPIC -O2@}]]}, +the test is first built with @option{-g -O0} by the compiler under +test and with @option{-O3} by the alternate compiler. The test is +built a second time using @option{-fpic} by the compiler under test +and @option{-fPIC -O2} by the alternate compiler. + +An alternate compiler is specified by defining an environment +variable to be the full pathname of an installed compiler; for C +define @env{ALT_CC_UNDER_TEST}, and for C++ define +@env{ALT_CXX_UNDER_TEST}. These will be written to the +@file{site.exp} file used by DejaGnu. The default is to build each +test with the compiler under test using the first of each pair of +compiler options from @env{COMPAT_OPTIONS}. When +@env{ALT_CC_UNDER_TEST} or +@env{ALT_CXX_UNDER_TEST} is @code{same}, each test is built using +the compiler under test but with combinations of the options from +@env{COMPAT_OPTIONS}. + +To run only the C++ compatibility suite using the compiler under test +and another version of GCC using specific compiler options, do the +following from @file{@var{objdir}/gcc}: + +@smallexample +rm site.exp +make -k \ + ALT_CXX_UNDER_TEST=$@{alt_prefix@}/bin/g++ \ + COMPAT_OPTIONS="lists as shown above" \ + check-c++ \ + RUNTESTFLAGS="compat.exp" +@end smallexample + +A test that fails when the source files are compiled with different +compilers, but passes when the files are compiled with the same +compiler, demonstrates incompatibility of the generated code or +runtime support. A test that fails for the alternate compiler but +passes for the compiler under test probably tests for a bug that was +fixed in the compiler under test but is present in the alternate +compiler. + +The binary compatibility tests support a small number of test framework +commands that appear within comments in a test file. + +@table @code +@item dg-require-* +These commands can be used in @file{@var{testname}_main.@var{suffix}} +to skip the test if specific support is not available on the target. + +@item dg-options +The specified options are used for compiling this particular source +file, appended to the options from @env{COMPAT_OPTIONS}. When this +command appears in @file{@var{testname}_main.@var{suffix}} the options +are also used to link the test program. + +@item dg-xfail-if +This command can be used in a secondary source file to specify that +compilation is expected to fail for particular options on particular +targets. +@end table diff --git a/gcc-4.2.1-5666.3/gcc/doc/standards.texi b/gcc-4.2.1-5666.3/gcc/doc/standards.texi new file mode 100644 index 000000000..e8cbac854 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/standards.texi @@ -0,0 +1,195 @@ +@c Copyright (C) 2000, 2001, 2002, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Standards +@chapter Language Standards Supported by GCC +@cindex C standard +@cindex C standards +@cindex ANSI C standard +@cindex ANSI C +@cindex ANSI C89 +@cindex C89 +@cindex ANSI X3.159-1989 +@cindex X3.159-1989 +@cindex ISO C standard +@cindex ISO C +@cindex ISO C90 +@cindex ISO/IEC 9899 +@cindex ISO 9899 +@cindex C90 +@cindex ISO C94 +@cindex C94 +@cindex ISO C95 +@cindex C95 +@cindex ISO C99 +@cindex C99 +@cindex ISO C9X +@cindex C9X +@cindex Technical Corrigenda +@cindex TC1 +@cindex Technical Corrigendum 1 +@cindex TC2 +@cindex Technical Corrigendum 2 +@cindex AMD1 +@cindex freestanding implementation +@cindex freestanding environment +@cindex hosted implementation +@cindex hosted environment +@findex __STDC_HOSTED__ + +For each language compiled by GCC for which there is a standard, GCC +attempts to follow one or more versions of that standard, possibly +with some exceptions, and possibly with some extensions. + +GCC supports three versions of the C standard, although support for +the most recent version is not yet complete. + +@opindex std +@opindex ansi +@opindex pedantic +@opindex pedantic-errors +The original ANSI C standard (X3.159-1989) was ratified in 1989 and +published in 1990. This standard was ratified as an ISO standard +(ISO/IEC 9899:1990) later in 1990. There were no technical +differences between these publications, although the sections of the +ANSI standard were renumbered and became clauses in the ISO standard. +This standard, in both its forms, is commonly known as @dfn{C89}, or +occasionally as @dfn{C90}, from the dates of ratification. The ANSI +standard, but not the ISO standard, also came with a Rationale +document. To select this standard in GCC, use one of the options +@option{-ansi}, @option{-std=c89} or @option{-std=iso9899:1990}; to obtain +all the diagnostics required by the standard, you should also specify +@option{-pedantic} (or @option{-pedantic-errors} if you want them to be +errors rather than warnings). @xref{C Dialect Options,,Options +Controlling C Dialect}. + +Errors in the 1990 ISO C standard were corrected in two Technical +Corrigenda published in 1994 and 1996. GCC does not support the +uncorrected version. + +An amendment to the 1990 standard was published in 1995. This +amendment added digraphs and @code{__STDC_VERSION__} to the language, +but otherwise concerned the library. This amendment is commonly known +as @dfn{AMD1}; the amended standard is sometimes known as @dfn{C94} or +@dfn{C95}. To select this standard in GCC, use the option +@option{-std=iso9899:199409} (with, as for other standard versions, +@option{-pedantic} to receive all required diagnostics). + +A new edition of the ISO C standard was published in 1999 as ISO/IEC +9899:1999, and is commonly known as @dfn{C99}. GCC has incomplete +support for this standard version; see +@uref{http://gcc.gnu.org/gcc-4.2/c99status.html} for details. To select this +standard, use @option{-std=c99} or @option{-std=iso9899:1999}. (While in +development, drafts of this standard version were referred to as +@dfn{C9X}.) + +Errors in the 1999 ISO C standard were corrected in two Technical +Corrigenda published in 2001 and 2004. GCC does not support the uncorrected +version. + +By default, GCC provides some extensions to the C language that on +rare occasions conflict with the C standard. @xref{C +Extensions,,Extensions to the C Language Family}. Use of the +@option{-std} options listed above will disable these extensions where +they conflict with the C standard version selected. You may also +select an extended version of the C language explicitly with +@option{-std=gnu89} (for C89 with GNU extensions) or @option{-std=gnu99} +(for C99 with GNU extensions). The default, if no C language dialect +options are given, is @option{-std=gnu89}; this will change to +@option{-std=gnu99} in some future release when the C99 support is +complete. Some features that are part of the C99 standard are +accepted as extensions in C89 mode. + +The ISO C standard defines (in clause 4) two classes of conforming +implementation. A @dfn{conforming hosted implementation} supports the +whole standard including all the library facilities; a @dfn{conforming +freestanding implementation} is only required to provide certain +library facilities: those in @code{<float.h>}, @code{<limits.h>}, +@code{<stdarg.h>}, and @code{<stddef.h>}; since AMD1, also those in +@code{<iso646.h>}; and in C99, also those in @code{<stdbool.h>} and +@code{<stdint.h>}. In addition, complex types, added in C99, are not +required for freestanding implementations. The standard also defines +two environments for programs, a @dfn{freestanding environment}, +required of all implementations and which may not have library +facilities beyond those required of freestanding implementations, +where the handling of program startup and termination are +implementation-defined, and a @dfn{hosted environment}, which is not +required, in which all the library facilities are provided and startup +is through a function @code{int main (void)} or @code{int main (int, +char *[])}. An OS kernel would be a freestanding environment; a +program using the facilities of an operating system would normally be +in a hosted implementation. + +@opindex ffreestanding +GCC aims towards being usable as a conforming freestanding +implementation, or as the compiler for a conforming hosted +implementation. By default, it will act as the compiler for a hosted +implementation, defining @code{__STDC_HOSTED__} as @code{1} and +presuming that when the names of ISO C functions are used, they have +the semantics defined in the standard. To make it act as a conforming +freestanding implementation for a freestanding environment, use the +option @option{-ffreestanding}; it will then define +@code{__STDC_HOSTED__} to @code{0} and not make assumptions about the +meanings of function names from the standard library, with exceptions +noted below. To build an OS kernel, you may well still need to make +your own arrangements for linking and startup. +@xref{C Dialect Options,,Options Controlling C Dialect}. + +GCC does not provide the library facilities required only of hosted +implementations, nor yet all the facilities required by C99 of +freestanding implementations; to use the facilities of a hosted +environment, you will need to find them elsewhere (for example, in the +GNU C library). @xref{Standard Libraries,,Standard Libraries}. + +Most of the compiler support routines used by GCC are present in +@file{libgcc}, but there are a few exceptions. GCC requires the +freestanding environment provide @code{memcpy}, @code{memmove}, +@code{memset} and @code{memcmp}. +Finally, if @code{__builtin_trap} is used, and the target does +not implement the @code{trap} pattern, then GCC will emit a call +to @code{abort}. + +For references to Technical Corrigenda, Rationale documents and +information concerning the history of C that is available online, see +@uref{http://gcc.gnu.org/readings.html} + +@c FIXME: details of C++ standard. + +@cindex Objective-C +@cindex Objective-C++ + +There is no formal written standard for Objective-C or Objective-C++@. The most +authoritative manual is ``Object-Oriented Programming and the +Objective-C Language'', available at a number of web sites: + +@itemize +@item +@uref{http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC/} +is a recent (and periodically updated) version; +@item +@uref{http://www.toodarkpark.org/computers/objc/} +is an older example; +@item +@uref{http://www.gnustep.org} +and +@uref{http://gcc.gnu.org/readings.html} +have additional useful information. +@end itemize + +@cindex treelang +There is no standard for treelang, which is a sample language front end +for GCC@. Its only purpose is as a sample for people wishing to write a +new language for GCC@. The language is documented in +@file{gcc/treelang/treelang.texi} which can be turned into info or +HTML format. + +@xref{Top, GNAT Reference Manual, About This Guide, gnat_rm, +GNAT Reference Manual}, for information on standard +conformance and compatibility of the Ada compiler. + +@xref{Standards,,Standards, gfortran, The GNU Fortran Compiler}, for details +of standards supported by GNU Fortran. + +@xref{Compatibility,,Compatibility with the Java Platform, gcj, GNU gcj}, +for details of compatibility between @command{gcj} and the Java Platform. diff --git a/gcc-4.2.1-5666.3/gcc/doc/tm.texi b/gcc-4.2.1-5666.3/gcc/doc/tm.texi new file mode 100644 index 000000000..606b5a295 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/tm.texi @@ -0,0 +1,10019 @@ +@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001, +@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Target Macros +@chapter Target Description Macros and Functions +@cindex machine description macros +@cindex target description macros +@cindex macros, target description +@cindex @file{tm.h} macros + +In addition to the file @file{@var{machine}.md}, a machine description +includes a C header file conventionally given the name +@file{@var{machine}.h} and a C source file named @file{@var{machine}.c}. +The header file defines numerous macros that convey the information +about the target machine that does not fit into the scheme of the +@file{.md} file. The file @file{tm.h} should be a link to +@file{@var{machine}.h}. The header file @file{config.h} includes +@file{tm.h} and most compiler source files include @file{config.h}. The +source file defines a variable @code{targetm}, which is a structure +containing pointers to functions and data relating to the target +machine. @file{@var{machine}.c} should also contain their definitions, +if they are not defined elsewhere in GCC, and other functions called +through the macros defined in the @file{.h} file. + +@menu +* Target Structure:: The @code{targetm} variable. +* Driver:: Controlling how the driver runs the compilation passes. +* Run-time Target:: Defining @samp{-m} options like @option{-m68000} and @option{-m68020}. +* Per-Function Data:: Defining data structures for per-function information. +* Storage Layout:: Defining sizes and alignments of data. +* Type Layout:: Defining sizes and properties of basic user data types. +* Registers:: Naming and describing the hardware registers. +* Register Classes:: Defining the classes of hardware registers. +* Old Constraints:: The old way to define machine-specific constraints. +* Stack and Calling:: Defining which way the stack grows and by how much. +* Varargs:: Defining the varargs macros. +* Trampolines:: Code set up at run time to enter a nested function. +* Library Calls:: Controlling how library routines are implicitly called. +* Addressing Modes:: Defining addressing modes valid for memory operands. +* Anchored Addresses:: Defining how @option{-fsection-anchors} should work. +* Condition Code:: Defining how insns update the condition code. +* Costs:: Defining relative costs of different operations. +* Scheduling:: Adjusting the behavior of the instruction scheduler. +* Sections:: Dividing storage into text, data, and other sections. +* PIC:: Macros for position independent code. +* Assembler Format:: Defining how to write insns and pseudo-ops to output. +* Debugging Info:: Defining the format of debugging output. +* Floating Point:: Handling floating point for cross-compilers. +* Mode Switching:: Insertion of mode-switching instructions. +* Target Attributes:: Defining target-specific uses of @code{__attribute__}. +* MIPS Coprocessors:: MIPS coprocessor support and how to customize it. +* PCH Target:: Validity checking for precompiled headers. +* C++ ABI:: Controlling C++ ABI changes. +* Misc:: Everything else. +@end menu + +@node Target Structure +@section The Global @code{targetm} Variable +@cindex target hooks +@cindex target functions + +@deftypevar {struct gcc_target} targetm +The target @file{.c} file must define the global @code{targetm} variable +which contains pointers to functions and data relating to the target +machine. The variable is declared in @file{target.h}; +@file{target-def.h} defines the macro @code{TARGET_INITIALIZER} which is +used to initialize the variable, and macros for the default initializers +for elements of the structure. The @file{.c} file should override those +macros for which the default definition is inappropriate. For example: +@smallexample +#include "target.h" +#include "target-def.h" + +/* @r{Initialize the GCC target structure.} */ + +#undef TARGET_COMP_TYPE_ATTRIBUTES +#define TARGET_COMP_TYPE_ATTRIBUTES @var{machine}_comp_type_attributes + +struct gcc_target targetm = TARGET_INITIALIZER; +@end smallexample +@end deftypevar + +Where a macro should be defined in the @file{.c} file in this manner to +form part of the @code{targetm} structure, it is documented below as a +``Target Hook'' with a prototype. Many macros will change in future +from being defined in the @file{.h} file to being part of the +@code{targetm} structure. + +@node Driver +@section Controlling the Compilation Driver, @file{gcc} +@cindex driver +@cindex controlling the compilation driver + +@c prevent bad page break with this line +You can control the compilation driver. + +@defmac SWITCH_TAKES_ARG (@var{char}) +A C expression which determines whether the option @option{-@var{char}} +takes arguments. The value should be the number of arguments that +option takes--zero, for many options. + +By default, this macro is defined as +@code{DEFAULT_SWITCH_TAKES_ARG}, which handles the standard options +properly. You need not define @code{SWITCH_TAKES_ARG} unless you +wish to add additional options which take arguments. Any redefinition +should call @code{DEFAULT_SWITCH_TAKES_ARG} and then check for +additional options. +@end defmac + +@defmac WORD_SWITCH_TAKES_ARG (@var{name}) +A C expression which determines whether the option @option{-@var{name}} +takes arguments. The value should be the number of arguments that +option takes--zero, for many options. This macro rather than +@code{SWITCH_TAKES_ARG} is used for multi-character option names. + +By default, this macro is defined as +@code{DEFAULT_WORD_SWITCH_TAKES_ARG}, which handles the standard options +properly. You need not define @code{WORD_SWITCH_TAKES_ARG} unless you +wish to add additional options which take arguments. Any redefinition +should call @code{DEFAULT_WORD_SWITCH_TAKES_ARG} and then check for +additional options. +@end defmac + +@defmac SWITCH_CURTAILS_COMPILATION (@var{char}) +A C expression which determines whether the option @option{-@var{char}} +stops compilation before the generation of an executable. The value is +boolean, nonzero if the option does stop an executable from being +generated, zero otherwise. + +By default, this macro is defined as +@code{DEFAULT_SWITCH_CURTAILS_COMPILATION}, which handles the standard +options properly. You need not define +@code{SWITCH_CURTAILS_COMPILATION} unless you wish to add additional +options which affect the generation of an executable. Any redefinition +should call @code{DEFAULT_SWITCH_CURTAILS_COMPILATION} and then check +for additional options. +@end defmac + +@defmac SWITCHES_NEED_SPACES +A string-valued C expression which enumerates the options for which +the linker needs a space between the option and its argument. + +If this macro is not defined, the default value is @code{""}. +@end defmac + +@defmac TARGET_OPTION_TRANSLATE_TABLE +If defined, a list of pairs of strings, the first of which is a +potential command line target to the @file{gcc} driver program, and the +second of which is a space-separated (tabs and other whitespace are not +supported) list of options with which to replace the first option. The +target defining this list is responsible for assuring that the results +are valid. Replacement options may not be the @code{--opt} style, they +must be the @code{-opt} style. It is the intention of this macro to +provide a mechanism for substitution that affects the multilibs chosen, +such as one option that enables many options, some of which select +multilibs. Example nonsensical definition, where @option{-malt-abi}, +@option{-EB}, and @option{-mspoo} cause different multilibs to be chosen: + +@smallexample +#define TARGET_OPTION_TRANSLATE_TABLE \ +@{ "-fast", "-march=fast-foo -malt-abi -I/usr/fast-foo" @}, \ +@{ "-compat", "-EB -malign=4 -mspoo" @} +@end smallexample +@end defmac + +@defmac DRIVER_SELF_SPECS +A list of specs for the driver itself. It should be a suitable +initializer for an array of strings, with no surrounding braces. + +The driver applies these specs to its own command line between loading +default @file{specs} files (but not command-line specified ones) and +choosing the multilib directory or running any subcommands. It +applies them in the order given, so each spec can depend on the +options added by earlier ones. It is also possible to remove options +using @samp{%<@var{option}} in the usual way. + +This macro can be useful when a port has several interdependent target +options. It provides a way of standardizing the command line so +that the other specs are easier to write. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac OPTION_DEFAULT_SPECS +A list of specs used to support configure-time default options (i.e.@: +@option{--with} options) in the driver. It should be a suitable initializer +for an array of structures, each containing two strings, without the +outermost pair of surrounding braces. + +The first item in the pair is the name of the default. This must match +the code in @file{config.gcc} for the target. The second item is a spec +to apply if a default with this name was specified. The string +@samp{%(VALUE)} in the spec will be replaced by the value of the default +everywhere it occurs. + +The driver will apply these specs to its own command line between loading +default @file{specs} files and processing @code{DRIVER_SELF_SPECS}, using +the same mechanism as @code{DRIVER_SELF_SPECS}. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac CPP_SPEC +A C string constant that tells the GCC driver program options to +pass to CPP@. It can also specify how to translate options you +give to GCC into options for GCC to pass to the CPP@. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac CPLUSPLUS_CPP_SPEC +This macro is just like @code{CPP_SPEC}, but is used for C++, rather +than C@. If you do not define this macro, then the value of +@code{CPP_SPEC} (if any) will be used instead. +@end defmac + +@defmac CC1_SPEC +A C string constant that tells the GCC driver program options to +pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language +front ends. +It can also specify how to translate options you give to GCC into options +for GCC to pass to front ends. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac CC1PLUS_SPEC +A C string constant that tells the GCC driver program options to +pass to @code{cc1plus}. It can also specify how to translate options you +give to GCC into options for GCC to pass to the @code{cc1plus}. + +Do not define this macro if it does not need to do anything. +Note that everything defined in CC1_SPEC is already passed to +@code{cc1plus} so there is no need to duplicate the contents of +CC1_SPEC in CC1PLUS_SPEC@. +@end defmac + +@defmac ASM_SPEC +A C string constant that tells the GCC driver program options to +pass to the assembler. It can also specify how to translate options +you give to GCC into options for GCC to pass to the assembler. +See the file @file{sun3.h} for an example of this. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac ASM_FINAL_SPEC +A C string constant that tells the GCC driver program how to +run any programs which cleanup after the normal assembler. +Normally, this is not needed. See the file @file{mips.h} for +an example of this. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac AS_NEEDS_DASH_FOR_PIPED_INPUT +Define this macro, with no value, if the driver should give the assembler +an argument consisting of a single dash, @option{-}, to instruct it to +read from its standard input (which will be a pipe connected to the +output of the compiler proper). This argument is given after any +@option{-o} option specifying the name of the output file. + +If you do not define this macro, the assembler is assumed to read its +standard input if given no non-option arguments. If your assembler +cannot read standard input at all, use a @samp{%@{pipe:%e@}} construct; +see @file{mips.h} for instance. +@end defmac + +@defmac LINK_SPEC +A C string constant that tells the GCC driver program options to +pass to the linker. It can also specify how to translate options you +give to GCC into options for GCC to pass to the linker. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac LIB_SPEC +Another C string constant used much like @code{LINK_SPEC}. The difference +between the two is that @code{LIB_SPEC} is used at the end of the +command given to the linker. + +If this macro is not defined, a default is provided that +loads the standard C library from the usual place. See @file{gcc.c}. +@end defmac + +@defmac LIBGCC_SPEC +Another C string constant that tells the GCC driver program +how and when to place a reference to @file{libgcc.a} into the +linker command line. This constant is placed both before and after +the value of @code{LIB_SPEC}. + +If this macro is not defined, the GCC driver provides a default that +passes the string @option{-lgcc} to the linker. +@end defmac + +@defmac REAL_LIBGCC_SPEC +By default, if @code{ENABLE_SHARED_LIBGCC} is defined, the +@code{LIBGCC_SPEC} is not directly used by the driver program but is +instead modified to refer to different versions of @file{libgcc.a} +depending on the values of the command line flags @option{-static}, +@option{-shared}, @option{-static-libgcc}, and @option{-shared-libgcc}. On +targets where these modifications are inappropriate, define +@code{REAL_LIBGCC_SPEC} instead. @code{REAL_LIBGCC_SPEC} tells the +driver how to place a reference to @file{libgcc} on the link command +line, but, unlike @code{LIBGCC_SPEC}, it is used unmodified. +@end defmac + +@defmac USE_LD_AS_NEEDED +A macro that controls the modifications to @code{LIBGCC_SPEC} +mentioned in @code{REAL_LIBGCC_SPEC}. If nonzero, a spec will be +generated that uses --as-needed and the shared libgcc in place of the +static exception handler library, when linking without any of +@code{-static}, @code{-static-libgcc}, or @code{-shared-libgcc}. +@end defmac + +@defmac LINK_EH_SPEC +If defined, this C string constant is added to @code{LINK_SPEC}. +When @code{USE_LD_AS_NEEDED} is zero or undefined, it also affects +the modifications to @code{LIBGCC_SPEC} mentioned in +@code{REAL_LIBGCC_SPEC}. +@end defmac + +@defmac STARTFILE_SPEC +Another C string constant used much like @code{LINK_SPEC}. The +difference between the two is that @code{STARTFILE_SPEC} is used at +the very beginning of the command given to the linker. + +If this macro is not defined, a default is provided that loads the +standard C startup file from the usual place. See @file{gcc.c}. +@end defmac + +@defmac ENDFILE_SPEC +Another C string constant used much like @code{LINK_SPEC}. The +difference between the two is that @code{ENDFILE_SPEC} is used at +the very end of the command given to the linker. + +Do not define this macro if it does not need to do anything. +@end defmac + +@defmac THREAD_MODEL_SPEC +GCC @code{-v} will print the thread model GCC was configured to use. +However, this doesn't work on platforms that are multilibbed on thread +models, such as AIX 4.3. On such platforms, define +@code{THREAD_MODEL_SPEC} such that it evaluates to a string without +blanks that names one of the recognized thread models. @code{%*}, the +default value of this macro, will expand to the value of +@code{thread_file} set in @file{config.gcc}. +@end defmac + +@defmac SYSROOT_SUFFIX_SPEC +Define this macro to add a suffix to the target sysroot when GCC is +configured with a sysroot. This will cause GCC to search for usr/lib, +et al, within sysroot+suffix. +@end defmac + +@defmac SYSROOT_HEADERS_SUFFIX_SPEC +Define this macro to add a headers_suffix to the target sysroot when +GCC is configured with a sysroot. This will cause GCC to pass the +updated sysroot+headers_suffix to CPP, causing it to search for +usr/include, et al, within sysroot+headers_suffix. +@end defmac + +@defmac EXTRA_SPECS +Define this macro to provide additional specifications to put in the +@file{specs} file that can be used in various specifications like +@code{CC1_SPEC}. + +The definition should be an initializer for an array of structures, +containing a string constant, that defines the specification name, and a +string constant that provides the specification. + +Do not define this macro if it does not need to do anything. + +@code{EXTRA_SPECS} is useful when an architecture contains several +related targets, which have various @code{@dots{}_SPECS} which are similar +to each other, and the maintainer would like one central place to keep +these definitions. + +For example, the PowerPC System V.4 targets use @code{EXTRA_SPECS} to +define either @code{_CALL_SYSV} when the System V calling sequence is +used or @code{_CALL_AIX} when the older AIX-based calling sequence is +used. + +The @file{config/rs6000/rs6000.h} target file defines: + +@smallexample +#define EXTRA_SPECS \ + @{ "cpp_sysv_default", CPP_SYSV_DEFAULT @}, + +#define CPP_SYS_DEFAULT "" +@end smallexample + +The @file{config/rs6000/sysv.h} target file defines: +@smallexample +#undef CPP_SPEC +#define CPP_SPEC \ +"%@{posix: -D_POSIX_SOURCE @} \ +%@{mcall-sysv: -D_CALL_SYSV @} \ +%@{!mcall-sysv: %(cpp_sysv_default) @} \ +%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}" + +#undef CPP_SYSV_DEFAULT +#define CPP_SYSV_DEFAULT "-D_CALL_SYSV" +@end smallexample + +while the @file{config/rs6000/eabiaix.h} target file defines +@code{CPP_SYSV_DEFAULT} as: + +@smallexample +#undef CPP_SYSV_DEFAULT +#define CPP_SYSV_DEFAULT "-D_CALL_AIX" +@end smallexample +@end defmac + +@defmac LINK_LIBGCC_SPECIAL_1 +Define this macro if the driver program should find the library +@file{libgcc.a}. If you do not define this macro, the driver program will pass +the argument @option{-lgcc} to tell the linker to do the search. +@end defmac + +@defmac LINK_GCC_C_SEQUENCE_SPEC +The sequence in which libgcc and libc are specified to the linker. +By default this is @code{%G %L %G}. +@end defmac + +@defmac LINK_COMMAND_SPEC +A C string constant giving the complete command line need to execute the +linker. When you do this, you will need to update your port each time a +change is made to the link command line within @file{gcc.c}. Therefore, +define this macro only if you need to completely redefine the command +line for invoking the linker and there is no other way to accomplish +the effect you need. Overriding this macro may be avoidable by overriding +@code{LINK_GCC_C_SEQUENCE_SPEC} instead. +@end defmac + +@defmac LINK_ELIMINATE_DUPLICATE_LDIRECTORIES +A nonzero value causes @command{collect2} to remove duplicate @option{-L@var{directory}} search +directories from linking commands. Do not give it a nonzero value if +removing duplicate search directories changes the linker's semantics. +@end defmac + +@defmac MULTILIB_DEFAULTS +Define this macro as a C expression for the initializer of an array of +string to tell the driver program which options are defaults for this +target and thus do not need to be handled specially when using +@code{MULTILIB_OPTIONS}. + +Do not define this macro if @code{MULTILIB_OPTIONS} is not defined in +the target makefile fragment or if none of the options listed in +@code{MULTILIB_OPTIONS} are set by default. +@xref{Target Fragment}. +@end defmac + +@defmac RELATIVE_PREFIX_NOT_LINKDIR +Define this macro to tell @command{gcc} that it should only translate +a @option{-B} prefix into a @option{-L} linker option if the prefix +indicates an absolute file name. +@end defmac + +@defmac MD_EXEC_PREFIX +If defined, this macro is an additional prefix to try after +@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched +when the @option{-b} option is used, or the compiler is built as a cross +compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it +to the list of directories used to find the assembler in @file{configure.in}. +@end defmac + +@defmac STANDARD_STARTFILE_PREFIX +Define this macro as a C string constant if you wish to override the +standard choice of @code{libdir} as the default prefix to +try when searching for startup files such as @file{crt0.o}. +@code{STANDARD_STARTFILE_PREFIX} is not searched when the compiler +is built as a cross compiler. +@end defmac + +@defmac STANDARD_STARTFILE_PREFIX_1 +Define this macro as a C string constant if you wish to override the +standard choice of @code{/lib} as a prefix to try after the default prefix +when searching for startup files such as @file{crt0.o}. +@code{STANDARD_STARTFILE_PREFIX_1} is not searched when the compiler +is built as a cross compiler. +@end defmac + +@defmac STANDARD_STARTFILE_PREFIX_2 +Define this macro as a C string constant if you wish to override the +standard choice of @code{/lib} as yet another prefix to try after the +default prefix when searching for startup files such as @file{crt0.o}. +@code{STANDARD_STARTFILE_PREFIX_2} is not searched when the compiler +is built as a cross compiler. +@end defmac + +@defmac MD_STARTFILE_PREFIX +If defined, this macro supplies an additional prefix to try after the +standard prefixes. @code{MD_EXEC_PREFIX} is not searched when the +@option{-b} option is used, or when the compiler is built as a cross +compiler. +@end defmac + +@defmac MD_STARTFILE_PREFIX_1 +If defined, this macro supplies yet another prefix to try after the +standard prefixes. It is not searched when the @option{-b} option is +used, or when the compiler is built as a cross compiler. +@end defmac + +@defmac INIT_ENVIRONMENT +Define this macro as a C string constant if you wish to set environment +variables for programs called by the driver, such as the assembler and +loader. The driver passes the value of this macro to @code{putenv} to +initialize the necessary environment variables. +@end defmac + +@defmac LOCAL_INCLUDE_DIR +Define this macro as a C string constant if you wish to override the +standard choice of @file{/usr/local/include} as the default prefix to +try when searching for local header files. @code{LOCAL_INCLUDE_DIR} +comes before @code{SYSTEM_INCLUDE_DIR} in the search order. + +Cross compilers do not search either @file{/usr/local/include} or its +replacement. +@end defmac + +@defmac MODIFY_TARGET_NAME +Define this macro if you wish to define command-line switches that +modify the default target name. + +For each switch, you can include a string to be appended to the first +part of the configuration name or a string to be deleted from the +configuration name, if present. The definition should be an initializer +for an array of structures. Each array element should have three +elements: the switch name (a string constant, including the initial +dash), one of the enumeration codes @code{ADD} or @code{DELETE} to +indicate whether the string should be inserted or deleted, and the string +to be inserted or deleted (a string constant). + +For example, on a machine where @samp{64} at the end of the +configuration name denotes a 64-bit target and you want the @option{-32} +and @option{-64} switches to select between 32- and 64-bit targets, you would +code + +@smallexample +#define MODIFY_TARGET_NAME \ + @{ @{ "-32", DELETE, "64"@}, \ + @{"-64", ADD, "64"@}@} +@end smallexample +@end defmac + +@defmac SYSTEM_INCLUDE_DIR +Define this macro as a C string constant if you wish to specify a +system-specific directory to search for header files before the standard +directory. @code{SYSTEM_INCLUDE_DIR} comes before +@code{STANDARD_INCLUDE_DIR} in the search order. + +Cross compilers do not use this macro and do not search the directory +specified. +@end defmac + +@defmac STANDARD_INCLUDE_DIR +Define this macro as a C string constant if you wish to override the +standard choice of @file{/usr/include} as the default prefix to +try when searching for header files. + +Cross compilers ignore this macro and do not search either +@file{/usr/include} or its replacement. +@end defmac + +@defmac STANDARD_INCLUDE_COMPONENT +The ``component'' corresponding to @code{STANDARD_INCLUDE_DIR}. +See @code{INCLUDE_DEFAULTS}, below, for the description of components. +If you do not define this macro, no component is used. +@end defmac + +@defmac INCLUDE_DEFAULTS +Define this macro if you wish to override the entire default search path +for include files. For a native compiler, the default search path +usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR}, +@code{SYSTEM_INCLUDE_DIR}, @code{GPLUSPLUS_INCLUDE_DIR}, and +@code{STANDARD_INCLUDE_DIR}. In addition, @code{GPLUSPLUS_INCLUDE_DIR} +and @code{GCC_INCLUDE_DIR} are defined automatically by @file{Makefile}, +and specify private search areas for GCC@. The directory +@code{GPLUSPLUS_INCLUDE_DIR} is used only for C++ programs. + +The definition should be an initializer for an array of structures. +Each array element should have four elements: the directory name (a +string constant), the component name (also a string constant), a flag +for C++-only directories, +and a flag showing that the includes in the directory don't need to be +wrapped in @code{extern @samp{C}} when compiling C++. Mark the end of +the array with a null element. + +The component name denotes what GNU package the include file is part of, +if any, in all uppercase letters. For example, it might be @samp{GCC} +or @samp{BINUTILS}. If the package is part of a vendor-supplied +operating system, code the component name as @samp{0}. + +For example, here is the definition used for VAX/VMS: + +@smallexample +#define INCLUDE_DEFAULTS \ +@{ \ + @{ "GNU_GXX_INCLUDE:", "G++", 1, 1@}, \ + @{ "GNU_CC_INCLUDE:", "GCC", 0, 0@}, \ + @{ "SYS$SYSROOT:[SYSLIB.]", 0, 0, 0@}, \ + @{ ".", 0, 0, 0@}, \ + @{ 0, 0, 0, 0@} \ +@} +@end smallexample +@end defmac + +Here is the order of prefixes tried for exec files: + +@enumerate +@item +Any prefixes specified by the user with @option{-B}. + +@item +The environment variable @code{GCC_EXEC_PREFIX}, if any. + +@item +The directories specified by the environment variable @code{COMPILER_PATH}. + +@item +The macro @code{STANDARD_EXEC_PREFIX}. + +@item +@file{/usr/lib/gcc/}. + +@item +The macro @code{MD_EXEC_PREFIX}, if any. +@end enumerate + +Here is the order of prefixes tried for startfiles: + +@enumerate +@item +Any prefixes specified by the user with @option{-B}. + +@item +The environment variable @code{GCC_EXEC_PREFIX}, if any. + +@item +The directories specified by the environment variable @code{LIBRARY_PATH} +(or port-specific name; native only, cross compilers do not use this). + +@item +The macro @code{STANDARD_EXEC_PREFIX}. + +@item +@file{/usr/lib/gcc/}. + +@item +The macro @code{MD_EXEC_PREFIX}, if any. + +@item +The macro @code{MD_STARTFILE_PREFIX}, if any. + +@item +The macro @code{STANDARD_STARTFILE_PREFIX}. + +@item +@file{/lib/}. + +@item +@file{/usr/lib/}. +@end enumerate + +@node Run-time Target +@section Run-time Target Specification +@cindex run-time target specification +@cindex predefined macros +@cindex target specifications + +@c prevent bad page break with this line +Here are run-time target specifications. + +@defmac TARGET_CPU_CPP_BUILTINS () +This function-like macro expands to a block of code that defines +built-in preprocessor macros and assertions for the target cpu, using +the functions @code{builtin_define}, @code{builtin_define_std} and +@code{builtin_assert}. When the front end +calls this macro it provides a trailing semicolon, and since it has +finished command line option processing your code can use those +results freely. + +@code{builtin_assert} takes a string in the form you pass to the +command-line option @option{-A}, such as @code{cpu=mips}, and creates +the assertion. @code{builtin_define} takes a string in the form +accepted by option @option{-D} and unconditionally defines the macro. + +@code{builtin_define_std} takes a string representing the name of an +object-like macro. If it doesn't lie in the user's namespace, +@code{builtin_define_std} defines it unconditionally. Otherwise, it +defines a version with two leading underscores, and another version +with two leading and trailing underscores, and defines the original +only if an ISO standard was not requested on the command line. For +example, passing @code{unix} defines @code{__unix}, @code{__unix__} +and possibly @code{unix}; passing @code{_mips} defines @code{__mips}, +@code{__mips__} and possibly @code{_mips}, and passing @code{_ABI64} +defines only @code{_ABI64}. + +You can also test for the C dialect being compiled. The variable +@code{c_language} is set to one of @code{clk_c}, @code{clk_cplusplus} +or @code{clk_objective_c}. Note that if we are preprocessing +assembler, this variable will be @code{clk_c} but the function-like +macro @code{preprocessing_asm_p()} will return true, so you might want +to check for that first. If you need to check for strict ANSI, the +variable @code{flag_iso} can be used. The function-like macro +@code{preprocessing_trad_p()} can be used to check for traditional +preprocessing. +@end defmac + +@defmac TARGET_OS_CPP_BUILTINS () +Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional +and is used for the target operating system instead. +@end defmac + +@defmac TARGET_OBJFMT_CPP_BUILTINS () +Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional +and is used for the target object format. @file{elfos.h} uses this +macro to define @code{__ELF__}, so you probably do not need to define +it yourself. +@end defmac + +@deftypevar {extern int} target_flags +This variable is declared in @file{options.h}, which is included before +any target-specific headers. +@end deftypevar + +@deftypevar {Target Hook} int TARGET_DEFAULT_TARGET_FLAGS +This variable specifies the initial value of @code{target_flags}. +Its default setting is 0. +@end deftypevar + +@cindex optional hardware or system features +@cindex features, optional, in system conventions + +@deftypefn {Target Hook} bool TARGET_HANDLE_OPTION (size_t @var{code}, const char *@var{arg}, int @var{value}) +This hook is called whenever the user specifies one of the +target-specific options described by the @file{.opt} definition files +(@pxref{Options}). It has the opportunity to do some option-specific +processing and should return true if the option is valid. The default +definition does nothing but return true. + +@var{code} specifies the @code{OPT_@var{name}} enumeration value +associated with the selected option; @var{name} is just a rendering of +the option name in which non-alphanumeric characters are replaced by +underscores. @var{arg} specifies the string argument and is null if +no argument was given. If the option is flagged as a @code{UInteger} +(@pxref{Option properties}), @var{value} is the numeric value of the +argument. Otherwise @var{value} is 1 if the positive form of the +option was used and 0 if the ``no-'' form was. +@end deftypefn + +@defmac TARGET_VERSION +This macro is a C statement to print on @code{stderr} a string +describing the particular machine description choice. Every machine +description should define @code{TARGET_VERSION}. For example: + +@smallexample +#ifdef MOTOROLA +#define TARGET_VERSION \ + fprintf (stderr, " (68k, Motorola syntax)"); +#else +#define TARGET_VERSION \ + fprintf (stderr, " (68k, MIT syntax)"); +#endif +@end smallexample +@end defmac + +@defmac OVERRIDE_OPTIONS +Sometimes certain combinations of command options do not make sense on +a particular target machine. You can define a macro +@code{OVERRIDE_OPTIONS} to take account of this. This macro, if +defined, is executed once just after all the command options have been +parsed. + +Don't use this macro to turn on various extra optimizations for +@option{-O}. That is what @code{OPTIMIZATION_OPTIONS} is for. +@end defmac + +@defmac C_COMMON_OVERRIDE_OPTIONS +This is similar to @code{OVERRIDE_OPTIONS} but is only used in the C +language frontends (C, Objective-C, C++, Objective-C++) and so can be +used to alter option flag variables which only exist in those +frontends. +@end defmac + +@defmac OPTIMIZATION_OPTIONS (@var{level}, @var{size}) +Some machines may desire to change what optimizations are performed for +various optimization levels. This macro, if defined, is executed once +just after the optimization level is determined and before the remainder +of the command options have been parsed. Values set in this macro are +used as the default values for the other command line options. + +@var{level} is the optimization level specified; 2 if @option{-O2} is +specified, 1 if @option{-O} is specified, and 0 if neither is specified. + +@var{size} is nonzero if @option{-Os} is specified and zero otherwise. + +You should not use this macro to change options that are not +machine-specific. These should uniformly selected by the same +optimization level on all supported machines. Use this macro to enable +machine-specific optimizations. + +@strong{Do not examine @code{write_symbols} in +this macro!} The debugging options are not supposed to alter the +generated code. +@end defmac + +@defmac CAN_DEBUG_WITHOUT_FP +Define this macro if debugging can be performed even without a frame +pointer. If this macro is defined, GCC will turn on the +@option{-fomit-frame-pointer} option whenever @option{-O} is specified. +@end defmac + +@node Per-Function Data +@section Defining data structures for per-function information. +@cindex per-function data +@cindex data structures + +If the target needs to store information on a per-function basis, GCC +provides a macro and a couple of variables to allow this. Note, just +using statics to store the information is a bad idea, since GCC supports +nested functions, so you can be halfway through encoding one function +when another one comes along. + +GCC defines a data structure called @code{struct function} which +contains all of the data specific to an individual function. This +structure contains a field called @code{machine} whose type is +@code{struct machine_function *}, which can be used by targets to point +to their own specific data. + +If a target needs per-function specific data it should define the type +@code{struct machine_function} and also the macro @code{INIT_EXPANDERS}. +This macro should be used to initialize the function pointer +@code{init_machine_status}. This pointer is explained below. + +One typical use of per-function, target specific data is to create an +RTX to hold the register containing the function's return address. This +RTX can then be used to implement the @code{__builtin_return_address} +function, for level 0. + +Note---earlier implementations of GCC used a single data area to hold +all of the per-function information. Thus when processing of a nested +function began the old per-function data had to be pushed onto a +stack, and when the processing was finished, it had to be popped off the +stack. GCC used to provide function pointers called +@code{save_machine_status} and @code{restore_machine_status} to handle +the saving and restoring of the target specific information. Since the +single data area approach is no longer used, these pointers are no +longer supported. + +@defmac INIT_EXPANDERS +Macro called to initialize any target specific information. This macro +is called once per function, before generation of any RTL has begun. +The intention of this macro is to allow the initialization of the +function pointer @code{init_machine_status}. +@end defmac + +@deftypevar {void (*)(struct function *)} init_machine_status +If this function pointer is non-@code{NULL} it will be called once per +function, before function compilation starts, in order to allow the +target to perform any target specific initialization of the +@code{struct function} structure. It is intended that this would be +used to initialize the @code{machine} of that structure. + +@code{struct machine_function} structures are expected to be freed by GC@. +Generally, any memory that they reference must be allocated by using +@code{ggc_alloc}, including the structure itself. +@end deftypevar + +@node Storage Layout +@section Storage Layout +@cindex storage layout + +Note that the definitions of the macros in this table which are sizes or +alignments measured in bits do not need to be constant. They can be C +expressions that refer to static variables, such as the @code{target_flags}. +@xref{Run-time Target}. + +@defmac BITS_BIG_ENDIAN +Define this macro to have the value 1 if the most significant bit in a +byte has the lowest number; otherwise define it to have the value zero. +This means that bit-field instructions count from the most significant +bit. If the machine has no bit-field instructions, then this must still +be defined, but it doesn't matter which value it is defined to. This +macro need not be a constant. + +This macro does not affect the way structure fields are packed into +bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}. +@end defmac + +@defmac BYTES_BIG_ENDIAN +Define this macro to have the value 1 if the most significant byte in a +word has the lowest number. This macro need not be a constant. +@end defmac + +@defmac WORDS_BIG_ENDIAN +Define this macro to have the value 1 if, in a multiword object, the +most significant word has the lowest number. This applies to both +memory locations and registers; GCC fundamentally assumes that the +order of words in memory is the same as the order in registers. This +macro need not be a constant. +@end defmac + +@defmac LIBGCC2_WORDS_BIG_ENDIAN +Define this macro if @code{WORDS_BIG_ENDIAN} is not constant. This must be a +constant value with the same meaning as @code{WORDS_BIG_ENDIAN}, which will be +used only when compiling @file{libgcc2.c}. Typically the value will be set +based on preprocessor defines. +@end defmac + +@defmac FLOAT_WORDS_BIG_ENDIAN +Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or +@code{TFmode} floating point numbers are stored in memory with the word +containing the sign bit at the lowest address; otherwise define it to +have the value 0. This macro need not be a constant. + +You need not define this macro if the ordering is the same as for +multi-word integers. +@end defmac + +@defmac BITS_PER_UNIT +Define this macro to be the number of bits in an addressable storage +unit (byte). If you do not define this macro the default is 8. +@end defmac + +@defmac BITS_PER_WORD +Number of bits in a word. If you do not define this macro, the default +is @code{BITS_PER_UNIT * UNITS_PER_WORD}. +@end defmac + +@defmac MAX_BITS_PER_WORD +Maximum number of bits in a word. If this is undefined, the default is +@code{BITS_PER_WORD}. Otherwise, it is the constant value that is the +largest value that @code{BITS_PER_WORD} can have at run-time. +@end defmac + +@defmac UNITS_PER_WORD +Number of storage units in a word; normally the size of a general-purpose +register, a power of two from 1 or 8. +@end defmac + +@defmac MIN_UNITS_PER_WORD +Minimum number of units in a word. If this is undefined, the default is +@code{UNITS_PER_WORD}. Otherwise, it is the constant value that is the +smallest value that @code{UNITS_PER_WORD} can have at run-time. +@end defmac + +@defmac UNITS_PER_SIMD_WORD +Number of units in the vectors that the vectorizer can produce. +The default is equal to @code{UNITS_PER_WORD}, because the vectorizer +can do some transformations even in absence of specialized @acronym{SIMD} +hardware. +@end defmac + +@defmac POINTER_SIZE +Width of a pointer, in bits. You must specify a value no wider than the +width of @code{Pmode}. If it is not equal to the width of @code{Pmode}, +you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify +a value the default is @code{BITS_PER_WORD}. +@end defmac + +@defmac POINTERS_EXTEND_UNSIGNED +A C expression whose value is greater than zero if pointers that need to be +extended from being @code{POINTER_SIZE} bits wide to @code{Pmode} are to +be zero-extended and zero if they are to be sign-extended. If the value +is less then zero then there must be an "ptr_extend" instruction that +extends a pointer from @code{POINTER_SIZE} to @code{Pmode}. + +You need not define this macro if the @code{POINTER_SIZE} is equal +to the width of @code{Pmode}. +@end defmac + +@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type}) +A macro to update @var{m} and @var{unsignedp} when an object whose type +is @var{type} and which has the specified mode and signedness is to be +stored in a register. This macro is only called when @var{type} is a +scalar type. + +On most RISC machines, which only have operations that operate on a full +register, define this macro to set @var{m} to @code{word_mode} if +@var{m} is an integer mode narrower than @code{BITS_PER_WORD}. In most +cases, only integer modes should be widened because wider-precision +floating-point operations are usually more expensive than their narrower +counterparts. + +For most machines, the macro definition does not change @var{unsignedp}. +However, some machines, have instructions that preferentially handle +either signed or unsigned quantities of certain modes. For example, on +the DEC Alpha, 32-bit loads from memory and 32-bit add instructions +sign-extend the result to 64 bits. On such machines, set +@var{unsignedp} according to which kind of extension is more efficient. + +Do not define this macro if it would never modify @var{m}. +@end defmac + +@defmac PROMOTE_FUNCTION_MODE +Like @code{PROMOTE_MODE}, but is applied to outgoing function arguments or +function return values, as specified by @code{TARGET_PROMOTE_FUNCTION_ARGS} +and @code{TARGET_PROMOTE_FUNCTION_RETURN}, respectively. + +The default is @code{PROMOTE_MODE}. +@end defmac + +@deftypefn {Target Hook} bool TARGET_PROMOTE_FUNCTION_ARGS (tree @var{fntype}) +This target hook should return @code{true} if the promotion described by +@code{PROMOTE_FUNCTION_MODE} should be done for outgoing function +arguments. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_PROMOTE_FUNCTION_RETURN (tree @var{fntype}) +This target hook should return @code{true} if the promotion described by +@code{PROMOTE_FUNCTION_MODE} should be done for the return value of +functions. + +If this target hook returns @code{true}, @code{TARGET_FUNCTION_VALUE} +must perform the same promotions done by @code{PROMOTE_FUNCTION_MODE}. +@end deftypefn + +@defmac PARM_BOUNDARY +Normal alignment required for function parameters on the stack, in +bits. All stack parameters receive at least this much alignment +regardless of data type. On most machines, this is the same as the +size of an integer. +@end defmac + +@defmac STACK_BOUNDARY +Define this macro to the minimum alignment enforced by hardware for the +stack pointer on this machine. The definition is a C expression for the +desired alignment (measured in bits). This value is used as a default +if @code{PREFERRED_STACK_BOUNDARY} is not defined. On most machines, +this should be the same as @code{PARM_BOUNDARY}. +@end defmac + +@defmac PREFERRED_STACK_BOUNDARY +Define this macro if you wish to preserve a certain alignment for the +stack pointer, greater than what the hardware enforces. The definition +is a C expression for the desired alignment (measured in bits). This +macro must evaluate to a value equal to or larger than +@code{STACK_BOUNDARY}. +@end defmac + +@defmac FUNCTION_BOUNDARY +Alignment required for a function entry point, in bits. +@end defmac + +@defmac BIGGEST_ALIGNMENT +Biggest alignment that any data type can require on this machine, in bits. +@end defmac + +@c APPLE LOCAL begin 5946347 ms_struct support +@defmac BIGGEST_MS_STRUCT_ALIGNMENT +Define this macro if the target supports Microsoft structure alignment +(@code{TARGET_MS_BITFIELD_LAYOUT_P}) and the target definition of +BIGGEST_ALIGNMENT is smaller than is needed for ms_struct records. It should +defined as the largest field alignment required by the target for Microsoft +aligned structure fields. + +By default, @code{BIGGEST_MS_STRUCT_ALIGNMENT} is defined to be equivalent to +@code{BIGGEST_ALIGNMENT}. +@end defmac + +@defmac TARGET_FIELD_MS_STRUCT_ALIGN +Define this macro if the target supports Microsoft structure alignment +(@code{TARGET_MS_BITFIELD_LAYOUT_P}) and the standard type alignment +of non-aggregate types is not sufficient for the MS structure alignment rules. + +The @code{TARGET_FIELD_MS_STRUCT_ALIGN} macro should return the alignment required +for the field passed as its argument. + +By default, the type alignment of the field will be used, i.e., +@code{TYPE_ALIGN (TREE_TYPE (FIELD))}. +@end defmac +@c APPLE LOCAL end 5946347 ms_struct support + +@defmac MINIMUM_ATOMIC_ALIGNMENT +If defined, the smallest alignment, in bits, that can be given to an +object that can be referenced in one operation, without disturbing any +nearby object. Normally, this is @code{BITS_PER_UNIT}, but may be larger +on machines that don't have byte or half-word store operations. +@end defmac + +@defmac BIGGEST_FIELD_ALIGNMENT +Biggest alignment that any structure or union field can require on this +machine, in bits. If defined, this overrides @code{BIGGEST_ALIGNMENT} for +structure and union fields only, unless the field alignment has been set +by the @code{__attribute__ ((aligned (@var{n})))} construct. +@end defmac + +@defmac ADJUST_FIELD_ALIGN (@var{field}, @var{computed}) +An expression for the alignment of a structure field @var{field} if the +alignment computed in the usual way (including applying of +@code{BIGGEST_ALIGNMENT} and @code{BIGGEST_FIELD_ALIGNMENT} to the +alignment) is @var{computed}. It overrides alignment only if the +field alignment has not been set by the +@code{__attribute__ ((aligned (@var{n})))} construct. +@end defmac + +@defmac MAX_OFILE_ALIGNMENT +Biggest alignment supported by the object file format of this machine. +Use this macro to limit the alignment which can be specified using the +@code{__attribute__ ((aligned (@var{n})))} construct. If not defined, +the default value is @code{BIGGEST_ALIGNMENT}. +@end defmac + +@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align}) +If defined, a C expression to compute the alignment for a variable in +the static store. @var{type} is the data type, and @var{basic-align} is +the alignment that the object would ordinarily have. The value of this +macro is used instead of that alignment to align the object. + +If this macro is not defined, then @var{basic-align} is used. + +@findex strcpy +One use of this macro is to increase alignment of medium-size data to +make it all fit in fewer cache lines. Another is to cause character +arrays to be word-aligned so that @code{strcpy} calls that copy +constants to character arrays can be done inline. +@end defmac + +@defmac CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align}) +If defined, a C expression to compute the alignment given to a constant +that is being placed in memory. @var{constant} is the constant and +@var{basic-align} is the alignment that the object would ordinarily +have. The value of this macro is used instead of that alignment to +align the object. + +If this macro is not defined, then @var{basic-align} is used. + +The typical use of this macro is to increase alignment for string +constants to be word aligned so that @code{strcpy} calls that copy +constants can be done inline. +@end defmac + +@defmac LOCAL_ALIGNMENT (@var{type}, @var{basic-align}) +If defined, a C expression to compute the alignment for a variable in +the local store. @var{type} is the data type, and @var{basic-align} is +the alignment that the object would ordinarily have. The value of this +macro is used instead of that alignment to align the object. + +If this macro is not defined, then @var{basic-align} is used. + +One use of this macro is to increase alignment of medium-size data to +make it all fit in fewer cache lines. +@end defmac + +@defmac EMPTY_FIELD_BOUNDARY +Alignment in bits to be given to a structure bit-field that follows an +empty field such as @code{int : 0;}. + +If @code{PCC_BITFIELD_TYPE_MATTERS} is true, it overrides this macro. +@end defmac + +@defmac STRUCTURE_SIZE_BOUNDARY +Number of bits which any structure or union's size must be a multiple of. +Each structure or union's size is rounded up to a multiple of this. + +If you do not define this macro, the default is the same as +@code{BITS_PER_UNIT}. +@end defmac + +@defmac STRICT_ALIGNMENT +Define this macro to be the value 1 if instructions will fail to work +if given data not on the nominal alignment. If instructions will merely +go slower in that case, define this macro as 0. +@end defmac + +@defmac PCC_BITFIELD_TYPE_MATTERS +Define this if you wish to imitate the way many other C compilers handle +alignment of bit-fields and the structures that contain them. + +The behavior is that the type written for a named bit-field (@code{int}, +@code{short}, or other integer type) imposes an alignment for the entire +structure, as if the structure really did contain an ordinary field of +that type. In addition, the bit-field is placed within the structure so +that it would fit within such a field, not crossing a boundary for it. + +Thus, on most machines, a named bit-field whose type is written as +@code{int} would not cross a four-byte boundary, and would force +four-byte alignment for the whole structure. (The alignment used may +not be four bytes; it is controlled by the other alignment parameters.) + +An unnamed bit-field will not affect the alignment of the containing +structure. + +If the macro is defined, its definition should be a C expression; +a nonzero value for the expression enables this behavior. + +Note that if this macro is not defined, or its value is zero, some +bit-fields may cross more than one alignment boundary. The compiler can +support such references if there are @samp{insv}, @samp{extv}, and +@samp{extzv} insns that can directly reference memory. + +The other known way of making bit-fields work is to define +@code{STRUCTURE_SIZE_BOUNDARY} as large as @code{BIGGEST_ALIGNMENT}. +Then every structure can be accessed with fullwords. + +Unless the machine has bit-field instructions or you define +@code{STRUCTURE_SIZE_BOUNDARY} that way, you must define +@code{PCC_BITFIELD_TYPE_MATTERS} to have a nonzero value. + +If your aim is to make GCC use the same conventions for laying out +bit-fields as are used by another compiler, here is how to investigate +what the other compiler does. Compile and run this program: + +@smallexample +struct foo1 +@{ + char x; + char :0; + char y; +@}; + +struct foo2 +@{ + char x; + int :0; + char y; +@}; + +main () +@{ + printf ("Size of foo1 is %d\n", + sizeof (struct foo1)); + printf ("Size of foo2 is %d\n", + sizeof (struct foo2)); + exit (0); +@} +@end smallexample + +If this prints 2 and 5, then the compiler's behavior is what you would +get from @code{PCC_BITFIELD_TYPE_MATTERS}. +@end defmac + +@defmac BITFIELD_NBYTES_LIMITED +Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited +to aligning a bit-field within the structure. +@end defmac + +@deftypefn {Target Hook} bool TARGET_ALIGN_ANON_BITFIELDS (void) +When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine +whether unnamed bitfields affect the alignment of the containing +structure. The hook should return true if the structure should inherit +the alignment requirements of an unnamed bitfield's type. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_NARROW_VOLATILE_BITFIELDS (void) +This target hook should return @code{true} if accesses to volatile bitfields +should use the narrowest mode possible. It should return @code{false} if +these accesses should use the bitfield container type. + +The default is @code{!TARGET_STRICT_ALIGN}. +@end deftypefn + +@defmac MEMBER_TYPE_FORCES_BLK (@var{field}, @var{mode}) +Return 1 if a structure or array containing @var{field} should be accessed using +@code{BLKMODE}. + +If @var{field} is the only field in the structure, @var{mode} is its +mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the +case where structures of one field would require the structure's mode to +retain the field's mode. + +Normally, this is not needed. See the file @file{c4x.h} for an example +of how to use this macro to prevent a structure having a floating point +field from being accessed in an integer mode. +@end defmac + +@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified}) +Define this macro as an expression for the alignment of a type (given +by @var{type} as a tree node) if the alignment computed in the usual +way is @var{computed} and the alignment explicitly specified was +@var{specified}. + +The default is to use @var{specified} if it is larger; otherwise, use +the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT} +@end defmac + +@defmac MAX_FIXED_MODE_SIZE +An integer expression for the size in bits of the largest integer +machine mode that should actually be used. All integer machine modes of +this size or smaller can be used for structures and unions with the +appropriate sizes. If this macro is undefined, @code{GET_MODE_BITSIZE +(DImode)} is assumed. +@end defmac + +@defmac STACK_SAVEAREA_MODE (@var{save_level}) +If defined, an expression of type @code{enum machine_mode} that +specifies the mode of the save area operand of a +@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}). +@var{save_level} is one of @code{SAVE_BLOCK}, @code{SAVE_FUNCTION}, or +@code{SAVE_NONLOCAL} and selects which of the three named patterns is +having its mode specified. + +You need not define this macro if it always returns @code{Pmode}. You +would most commonly define this macro if the +@code{save_stack_@var{level}} patterns need to support both a 32- and a +64-bit mode. +@end defmac + +@defmac STACK_SIZE_MODE +If defined, an expression of type @code{enum machine_mode} that +specifies the mode of the size increment operand of an +@code{allocate_stack} named pattern (@pxref{Standard Names}). + +You need not define this macro if it always returns @code{word_mode}. +You would most commonly define this macro if the @code{allocate_stack} +pattern needs to support both a 32- and a 64-bit mode. +@end defmac + +@defmac TARGET_FLOAT_FORMAT +A code distinguishing the floating point format of the target machine. +There are four defined values: + +@ftable @code +@item IEEE_FLOAT_FORMAT +This code indicates IEEE floating point. It is the default; there is no +need to define @code{TARGET_FLOAT_FORMAT} when the format is IEEE@. + +@item VAX_FLOAT_FORMAT +This code indicates the ``F float'' (for @code{float}) and ``D float'' +or ``G float'' formats (for @code{double}) used on the VAX and PDP-11@. + +@item IBM_FLOAT_FORMAT +This code indicates the format used on the IBM System/370. + +@item C4X_FLOAT_FORMAT +This code indicates the format used on the TMS320C3x/C4x. +@end ftable + +If your target uses a floating point format other than these, you must +define a new @var{name}_FLOAT_FORMAT code for it, and add support for +it to @file{real.c}. + +The ordering of the component words of floating point values stored in +memory is controlled by @code{FLOAT_WORDS_BIG_ENDIAN}. +@end defmac + +@defmac MODE_HAS_NANS (@var{mode}) +When defined, this macro should be true if @var{mode} has a NaN +representation. The compiler assumes that NaNs are not equal to +anything (including themselves) and that addition, subtraction, +multiplication and division all return NaNs when one operand is +NaN@. + +By default, this macro is true if @var{mode} is a floating-point +mode and the target floating-point format is IEEE@. +@end defmac + +@defmac MODE_HAS_INFINITIES (@var{mode}) +This macro should be true if @var{mode} can represent infinity. At +present, the compiler uses this macro to decide whether @samp{x - x} +is always defined. By default, the macro is true when @var{mode} +is a floating-point mode and the target format is IEEE@. +@end defmac + +@defmac MODE_HAS_SIGNED_ZEROS (@var{mode}) +True if @var{mode} distinguishes between positive and negative zero. +The rules are expected to follow the IEEE standard: + +@itemize @bullet +@item +@samp{x + x} has the same sign as @samp{x}. + +@item +If the sum of two values with opposite sign is zero, the result is +positive for all rounding modes expect towards @minus{}infinity, for +which it is negative. + +@item +The sign of a product or quotient is negative when exactly one +of the operands is negative. +@end itemize + +The default definition is true if @var{mode} is a floating-point +mode and the target format is IEEE@. +@end defmac + +@defmac MODE_HAS_SIGN_DEPENDENT_ROUNDING (@var{mode}) +If defined, this macro should be true for @var{mode} if it has at +least one rounding mode in which @samp{x} and @samp{-x} can be +rounded to numbers of different magnitude. Two such modes are +towards @minus{}infinity and towards +infinity. + +The default definition of this macro is true if @var{mode} is +a floating-point mode and the target format is IEEE@. +@end defmac + +@defmac ROUND_TOWARDS_ZERO +If defined, this macro should be true if the prevailing rounding +mode is towards zero. A true value has the following effects: + +@itemize @bullet +@item +@code{MODE_HAS_SIGN_DEPENDENT_ROUNDING} will be false for all modes. + +@item +@file{libgcc.a}'s floating-point emulator will round towards zero +rather than towards nearest. + +@item +The compiler's floating-point emulator will round towards zero after +doing arithmetic, and when converting from the internal float format to +the target format. +@end itemize + +The macro does not affect the parsing of string literals. When the +primary rounding mode is towards zero, library functions like +@code{strtod} might still round towards nearest, and the compiler's +parser should behave like the target's @code{strtod} where possible. + +Not defining this macro is equivalent to returning zero. +@end defmac + +@defmac LARGEST_EXPONENT_IS_NORMAL (@var{size}) +This macro should return true if floats with @var{size} +bits do not have a NaN or infinity representation, but use the largest +exponent for normal numbers instead. + +Defining this macro to true for @var{size} causes @code{MODE_HAS_NANS} +and @code{MODE_HAS_INFINITIES} to be false for @var{size}-bit modes. +It also affects the way @file{libgcc.a} and @file{real.c} emulate +floating-point arithmetic. + +The default definition of this macro returns false for all sizes. +@end defmac + +@deftypefn {Target Hook} bool TARGET_VECTOR_OPAQUE_P (tree @var{type}) +This target hook should return @code{true} a vector is opaque. That +is, if no cast is needed when copying a vector value of type +@var{type} into another vector lvalue of the same size. Vector opaque +types cannot be initialized. The default is that there are no such +types. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_MS_BITFIELD_LAYOUT_P (tree @var{record_type}) +This target hook returns @code{true} if bit-fields in the given +@var{record_type} are to be laid out following the rules of Microsoft +Visual C/C++, namely: (i) a bit-field won't share the same storage +unit with the previous bit-field if their underlying types have +different sizes, and the bit-field will be aligned to the highest +alignment of the underlying types of itself and of the previous +bit-field; (ii) a zero-sized bit-field will affect the alignment of +the whole enclosing structure, even if it is unnamed; except that +(iii) a zero-sized bit-field will be disregarded unless it follows +another bit-field of nonzero size. If this hook returns @code{true}, +other macros that control bit-field layout are ignored. + +When a bit-field is inserted into a packed record, the whole size +of the underlying type is used by one or more same-size adjacent +bit-fields (that is, if its long:3, 32 bits is used in the record, +and any additional adjacent long bit-fields are packed into the same +chunk of 32 bits. However, if the size changes, a new field of that +size is allocated). In an unpacked record, this is the same as using +alignment, but not equivalent when packing. + +If both MS bit-fields and @samp{__attribute__((packed))} are used, +the latter will take precedence. If @samp{__attribute__((packed))} is +used on a single field when MS bit-fields are in use, it will take +precedence for that field, but the alignment of the rest of the structure +may affect its placement. +@end deftypefn + +@deftypefn {Target Hook} {bool} TARGET_DECIMAL_FLOAT_SUPPORTED_P (void) +Returns true if the target supports decimal floating point. +@end deftypefn + +@c APPLE LOCAL begin mangle_type 7105099 +@deftypefn {Target Hook} {const char *} TARGET_MANGLE_TYPE (tree @var{type}) +If your target defines any fundamental types, or any types your target +uses should be mangled differently from the default, define this hook +to return the appropriate encoding for these types as part of a C++ +mangled name. The @var{type} argument is the tree structure representing +the type to be mangled. The hook may be applied to trees which are +not target-specific fundamental types; it should return @code{NULL} +for all such types, as well as arguments it does not recognize. If the +return value is not @code{NULL}, it must point to a statically-allocated +string constant. +@c APPLE LOCAL end mangle_type 7105099 + +Target-specific fundamental types might be new fundamental types or +qualified versions of ordinary fundamental types. Encode new +fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name} +is the name used for the type in source code, and @var{n} is the +length of @var{name} in decimal. Encode qualified versions of +ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where +@var{name} is the name used for the type qualifier in source code, +@var{n} is the length of @var{name} as above, and @var{code} is the +code used to represent the unqualified version of this type. (See +@code{write_builtin_type} in @file{cp/mangle.c} for the list of +codes.) In both cases the spaces are for clarity; do not include any +spaces in your string. + +@c APPLE LOCAL begin mangle_type 7105099 +This hook is applied to types prior to typedef resolution. If the mangled +name for a particular type depends only on that type's main variant, you +can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT} +before mangling. +@c APPLE LOCAL end mangle_type 7105099 + +The default version of this hook always returns @code{NULL}, which is +appropriate for a target that does not define any new fundamental +types. +@end deftypefn + +@node Type Layout +@section Layout of Source Language Data Types + +These macros define the sizes and other characteristics of the standard +basic data types used in programs being compiled. Unlike the macros in +the previous section, these apply to specific features of C and related +languages, rather than to fundamental aspects of storage layout. + +@defmac INT_TYPE_SIZE +A C expression for the size in bits of the type @code{int} on the +target machine. If you don't define this, the default is one word. +@end defmac + +@defmac SHORT_TYPE_SIZE +A C expression for the size in bits of the type @code{short} on the +target machine. If you don't define this, the default is half a word. +(If this would be less than one storage unit, it is rounded up to one +unit.) +@end defmac + +@defmac LONG_TYPE_SIZE +A C expression for the size in bits of the type @code{long} on the +target machine. If you don't define this, the default is one word. +@end defmac + +@defmac ADA_LONG_TYPE_SIZE +On some machines, the size used for the Ada equivalent of the type +@code{long} by a native Ada compiler differs from that used by C@. In +that situation, define this macro to be a C expression to be used for +the size of that type. If you don't define this, the default is the +value of @code{LONG_TYPE_SIZE}. +@end defmac + +@defmac LONG_LONG_TYPE_SIZE +A C expression for the size in bits of the type @code{long long} on the +target machine. If you don't define this, the default is two +words. If you want to support GNU Ada on your machine, the value of this +macro must be at least 64. +@end defmac + +@defmac CHAR_TYPE_SIZE +A C expression for the size in bits of the type @code{char} on the +target machine. If you don't define this, the default is +@code{BITS_PER_UNIT}. +@end defmac + +@defmac BOOL_TYPE_SIZE +A C expression for the size in bits of the C++ type @code{bool} and +C99 type @code{_Bool} on the target machine. If you don't define +this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}. +@end defmac + +@defmac FLOAT_TYPE_SIZE +A C expression for the size in bits of the type @code{float} on the +target machine. If you don't define this, the default is one word. +@end defmac + +@defmac DOUBLE_TYPE_SIZE +A C expression for the size in bits of the type @code{double} on the +target machine. If you don't define this, the default is two +words. +@end defmac + +@defmac LONG_DOUBLE_TYPE_SIZE +A C expression for the size in bits of the type @code{long double} on +the target machine. If you don't define this, the default is two +words. +@end defmac + +@defmac LIBGCC2_LONG_DOUBLE_TYPE_SIZE +Define this macro if @code{LONG_DOUBLE_TYPE_SIZE} is not constant or +if you want routines in @file{libgcc2.a} for a size other than +@code{LONG_DOUBLE_TYPE_SIZE}. If you don't define this, the +default is @code{LONG_DOUBLE_TYPE_SIZE}. +@end defmac + +@defmac LIBGCC2_HAS_DF_MODE +Define this macro if neither @code{LIBGCC2_DOUBLE_TYPE_SIZE} nor +@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is +@code{DFmode} but you want @code{DFmode} routines in @file{libgcc2.a} +anyway. If you don't define this and either @code{LIBGCC2_DOUBLE_TYPE_SIZE} +or @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64 then the default is 1, +otherwise it is 0. +@end defmac + +@defmac LIBGCC2_HAS_XF_MODE +Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not +@code{XFmode} but you want @code{XFmode} routines in @file{libgcc2.a} +anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} +is 80 then the default is 1, otherwise it is 0. +@end defmac + +@defmac LIBGCC2_HAS_TF_MODE +Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not +@code{TFmode} but you want @code{TFmode} routines in @file{libgcc2.a} +anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} +is 128 then the default is 1, otherwise it is 0. +@end defmac + +@defmac SF_SIZE +@defmacx DF_SIZE +@defmacx XF_SIZE +@defmacx TF_SIZE +Define these macros to be the size in bits of the mantissa of +@code{SFmode}, @code{DFmode}, @code{XFmode} and @code{TFmode} values, +if the defaults in @file{libgcc2.h} are inappropriate. By default, +@code{FLT_MANT_DIG} is used for @code{SF_SIZE}, @code{LDBL_MANT_DIG} +for @code{XF_SIZE} and @code{TF_SIZE}, and @code{DBL_MANT_DIG} or +@code{LDBL_MANT_DIG} for @code{DF_SIZE} according to whether +@code{LIBGCC2_DOUBLE_TYPE_SIZE} or +@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64. +@end defmac + +@defmac TARGET_FLT_EVAL_METHOD +A C expression for the value for @code{FLT_EVAL_METHOD} in @file{float.h}, +assuming, if applicable, that the floating-point control word is in its +default state. If you do not define this macro the value of +@code{FLT_EVAL_METHOD} will be zero. +@end defmac + +@defmac WIDEST_HARDWARE_FP_SIZE +A C expression for the size in bits of the widest floating-point format +supported by the hardware. If you define this macro, you must specify a +value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}. +If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE} +is the default. +@end defmac + +@defmac DEFAULT_SIGNED_CHAR +An expression whose value is 1 or 0, according to whether the type +@code{char} should be signed or unsigned by default. The user can +always override this default with the options @option{-fsigned-char} +and @option{-funsigned-char}. +@end defmac + +@deftypefn {Target Hook} bool TARGET_DEFAULT_SHORT_ENUMS (void) +This target hook should return true if the compiler should give an +@code{enum} type only as many bytes as it takes to represent the range +of possible values of that type. It should return false if all +@code{enum} types should be allocated like @code{int}. + +The default is to return false. +@end deftypefn + +@defmac SIZE_TYPE +A C expression for a string describing the name of the data type to use +for size values. The typedef name @code{size_t} is defined using the +contents of the string. + +The string can contain more than one keyword. If so, separate them with +spaces, and write first any length keyword, then @code{unsigned} if +appropriate, and finally @code{int}. The string must exactly match one +of the data type names defined in the function +@code{init_decl_processing} in the file @file{c-decl.c}. You may not +omit @code{int} or change the order---that would cause the compiler to +crash on startup. + +If you don't define this macro, the default is @code{"long unsigned +int"}. +@end defmac + +@defmac PTRDIFF_TYPE +A C expression for a string describing the name of the data type to use +for the result of subtracting two pointers. The typedef name +@code{ptrdiff_t} is defined using the contents of the string. See +@code{SIZE_TYPE} above for more information. + +If you don't define this macro, the default is @code{"long int"}. +@end defmac + +@defmac WCHAR_TYPE +A C expression for a string describing the name of the data type to use +for wide characters. The typedef name @code{wchar_t} is defined using +the contents of the string. See @code{SIZE_TYPE} above for more +information. + +If you don't define this macro, the default is @code{"int"}. +@end defmac + +@defmac WCHAR_TYPE_SIZE +A C expression for the size in bits of the data type for wide +characters. This is used in @code{cpp}, which cannot make use of +@code{WCHAR_TYPE}. +@end defmac + +@defmac WINT_TYPE +A C expression for a string describing the name of the data type to +use for wide characters passed to @code{printf} and returned from +@code{getwc}. The typedef name @code{wint_t} is defined using the +contents of the string. See @code{SIZE_TYPE} above for more +information. + +If you don't define this macro, the default is @code{"unsigned int"}. +@end defmac + +@defmac INTMAX_TYPE +A C expression for a string describing the name of the data type that +can represent any value of any standard or extended signed integer type. +The typedef name @code{intmax_t} is defined using the contents of the +string. See @code{SIZE_TYPE} above for more information. + +If you don't define this macro, the default is the first of +@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as +much precision as @code{long long int}. +@end defmac + +@defmac UINTMAX_TYPE +A C expression for a string describing the name of the data type that +can represent any value of any standard or extended unsigned integer +type. The typedef name @code{uintmax_t} is defined using the contents +of the string. See @code{SIZE_TYPE} above for more information. + +If you don't define this macro, the default is the first of +@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long +unsigned int"} that has as much precision as @code{long long unsigned +int}. +@end defmac + +@defmac TARGET_PTRMEMFUNC_VBIT_LOCATION +The C++ compiler represents a pointer-to-member-function with a struct +that looks like: + +@smallexample + struct @{ + union @{ + void (*fn)(); + ptrdiff_t vtable_index; + @}; + ptrdiff_t delta; + @}; +@end smallexample + +@noindent +The C++ compiler must use one bit to indicate whether the function that +will be called through a pointer-to-member-function is virtual. +Normally, we assume that the low-order bit of a function pointer must +always be zero. Then, by ensuring that the vtable_index is odd, we can +distinguish which variant of the union is in use. But, on some +platforms function pointers can be odd, and so this doesn't work. In +that case, we use the low-order bit of the @code{delta} field, and shift +the remainder of the @code{delta} field to the left. + +GCC will automatically make the right selection about where to store +this bit using the @code{FUNCTION_BOUNDARY} setting for your platform. +However, some platforms such as ARM/Thumb have @code{FUNCTION_BOUNDARY} +set such that functions always start at even addresses, but the lowest +bit of pointers to functions indicate whether the function at that +address is in ARM or Thumb mode. If this is the case of your +architecture, you should define this macro to +@code{ptrmemfunc_vbit_in_delta}. + +In general, you should not have to define this macro. On architectures +in which function addresses are always even, according to +@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to +@code{ptrmemfunc_vbit_in_pfn}. +@end defmac + +@defmac TARGET_VTABLE_USES_DESCRIPTORS +Normally, the C++ compiler uses function pointers in vtables. This +macro allows the target to change to use ``function descriptors'' +instead. Function descriptors are found on targets for whom a +function pointer is actually a small data structure. Normally the +data structure consists of the actual code address plus a data +pointer to which the function's data is relative. + +If vtables are used, the value of this macro should be the number +of words that the function descriptor occupies. +@end defmac + +@defmac TARGET_VTABLE_ENTRY_ALIGN +By default, the vtable entries are void pointers, the so the alignment +is the same as pointer alignment. The value of this macro specifies +the alignment of the vtable entry in bits. It should be defined only +when special alignment is necessary. */ +@end defmac + +@defmac TARGET_VTABLE_DATA_ENTRY_DISTANCE +There are a few non-descriptor entries in the vtable at offsets below +zero. If these entries must be padded (say, to preserve the alignment +specified by @code{TARGET_VTABLE_ENTRY_ALIGN}), set this to the number +of words in each data entry. +@end defmac + +@node Registers +@section Register Usage +@cindex register usage + +This section explains how to describe what registers the target machine +has, and how (in general) they can be used. + +The description of which registers a specific instruction can use is +done with register classes; see @ref{Register Classes}. For information +on using registers to access a stack frame, see @ref{Frame Registers}. +For passing values in registers, see @ref{Register Arguments}. +For returning values in registers, see @ref{Scalar Return}. + +@menu +* Register Basics:: Number and kinds of registers. +* Allocation Order:: Order in which registers are allocated. +* Values in Registers:: What kinds of values each reg can hold. +* Leaf Functions:: Renumbering registers for leaf functions. +* Stack Registers:: Handling a register stack such as 80387. +@end menu + +@node Register Basics +@subsection Basic Characteristics of Registers + +@c prevent bad page break with this line +Registers have various characteristics. + +@defmac FIRST_PSEUDO_REGISTER +Number of hardware registers known to the compiler. They receive +numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first +pseudo register's number really is assigned the number +@code{FIRST_PSEUDO_REGISTER}. +@end defmac + +@defmac FIXED_REGISTERS +@cindex fixed register +An initializer that says which registers are used for fixed purposes +all throughout the compiled code and are therefore not available for +general allocation. These would include the stack pointer, the frame +pointer (except on machines where that can be used as a general +register when no frame pointer is needed), the program counter on +machines where that is considered one of the addressable registers, +and any other numbered register with a standard use. + +This information is expressed as a sequence of numbers, separated by +commas and surrounded by braces. The @var{n}th number is 1 if +register @var{n} is fixed, 0 otherwise. + +The table initialized from this macro, and the table initialized by +the following one, may be overridden at run time either automatically, +by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by +the user with the command options @option{-ffixed-@var{reg}}, +@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}. +@end defmac + +@defmac CALL_USED_REGISTERS +@cindex call-used register +@cindex call-clobbered register +@cindex call-saved register +Like @code{FIXED_REGISTERS} but has 1 for each register that is +clobbered (in general) by function calls as well as for fixed +registers. This macro therefore identifies the registers that are not +available for general allocation of values that must live across +function calls. + +If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler +automatically saves it on function entry and restores it on function +exit, if the register is used within the function. +@end defmac + +@defmac CALL_REALLY_USED_REGISTERS +@cindex call-used register +@cindex call-clobbered register +@cindex call-saved register +Like @code{CALL_USED_REGISTERS} except this macro doesn't require +that the entire set of @code{FIXED_REGISTERS} be included. +(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}). +This macro is optional. If not specified, it defaults to the value +of @code{CALL_USED_REGISTERS}. +@end defmac + +@defmac HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode}) +@cindex call-used register +@cindex call-clobbered register +@cindex call-saved register +A C expression that is nonzero if it is not permissible to store a +value of mode @var{mode} in hard register number @var{regno} across a +call without some part of it being clobbered. For most machines this +macro need not be defined. It is only required for machines that do not +preserve the entire contents of a register across a call. +@end defmac + +@findex fixed_regs +@findex call_used_regs +@findex global_regs +@findex reg_names +@findex reg_class_contents +@defmac CONDITIONAL_REGISTER_USAGE +Zero or more C statements that may conditionally modify five variables +@code{fixed_regs}, @code{call_used_regs}, @code{global_regs}, +@code{reg_names}, and @code{reg_class_contents}, to take into account +any dependence of these register sets on target flags. The first three +of these are of type @code{char []} (interpreted as Boolean vectors). +@code{global_regs} is a @code{const char *[]}, and +@code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is +called, @code{fixed_regs}, @code{call_used_regs}, +@code{reg_class_contents}, and @code{reg_names} have been initialized +from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS}, +@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively. +@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}}, +@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}} +command options have been applied. + +You need not define this macro if it has no work to do. + +@cindex disabling certain registers +@cindex controlling register usage +If the usage of an entire class of registers depends on the target +flags, you may indicate this to GCC by using this macro to modify +@code{fixed_regs} and @code{call_used_regs} to 1 for each of the +registers in the classes which should not be used by GCC@. Also define +the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT} +to return @code{NO_REGS} if it +is called with a letter for a class that shouldn't be used. + +(However, if this class is not included in @code{GENERAL_REGS} and all +of the insn patterns whose constraints permit this class are +controlled by target switches, then GCC will automatically avoid using +these registers when the target switches are opposed to them.) +@end defmac + +@defmac INCOMING_REGNO (@var{out}) +Define this macro if the target machine has register windows. This C +expression returns the register number as seen by the called function +corresponding to the register number @var{out} as seen by the calling +function. Return @var{out} if register number @var{out} is not an +outbound register. +@end defmac + +@defmac OUTGOING_REGNO (@var{in}) +Define this macro if the target machine has register windows. This C +expression returns the register number as seen by the calling function +corresponding to the register number @var{in} as seen by the called +function. Return @var{in} if register number @var{in} is not an inbound +register. +@end defmac + +@defmac LOCAL_REGNO (@var{regno}) +Define this macro if the target machine has register windows. This C +expression returns true if the register is call-saved but is in the +register window. Unlike most call-saved registers, such registers +need not be explicitly restored on function exit or during non-local +gotos. +@end defmac + +@defmac PC_REGNUM +If the program counter has a register number, define this as that +register number. Otherwise, do not define it. +@end defmac + +@node Allocation Order +@subsection Order of Allocation of Registers +@cindex order of register allocation +@cindex register allocation order + +@c prevent bad page break with this line +Registers are allocated in order. + +@defmac REG_ALLOC_ORDER +If defined, an initializer for a vector of integers, containing the +numbers of hard registers in the order in which GCC should prefer +to use them (from most preferred to least). + +If this macro is not defined, registers are used lowest numbered first +(all else being equal). + +One use of this macro is on machines where the highest numbered +registers must always be saved and the save-multiple-registers +instruction supports only sequences of consecutive registers. On such +machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists +the highest numbered allocable register first. +@end defmac + +@defmac ORDER_REGS_FOR_LOCAL_ALLOC +A C statement (sans semicolon) to choose the order in which to allocate +hard registers for pseudo-registers local to a basic block. + +Store the desired register order in the array @code{reg_alloc_order}. +Element 0 should be the register to allocate first; element 1, the next +register; and so on. + +The macro body should not assume anything about the contents of +@code{reg_alloc_order} before execution of the macro. + +On most machines, it is not necessary to define this macro. +@end defmac + +@node Values in Registers +@subsection How Values Fit in Registers + +This section discusses the macros that describe which kinds of values +(specifically, which machine modes) each register can hold, and how many +consecutive registers are needed for a given mode. + +@defmac HARD_REGNO_NREGS (@var{regno}, @var{mode}) +A C expression for the number of consecutive hard registers, starting +at register number @var{regno}, required to hold a value of mode +@var{mode}. + +On a machine where all registers are exactly one word, a suitable +definition of this macro is + +@smallexample +#define HARD_REGNO_NREGS(REGNO, MODE) \ + ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) \ + / UNITS_PER_WORD) +@end smallexample +@end defmac + +@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode}) +A C expression that is nonzero if a value of mode @var{mode}, stored +in memory, ends with padding that causes it to take up more space than +in registers starting at register number @var{regno} (as determined by +multiplying GCC's notion of the size of the register when containing +this mode by the number of registers returned by +@code{HARD_REGNO_NREGS}). By default this is zero. + +For example, if a floating-point value is stored in three 32-bit +registers but takes up 128 bits in memory, then this would be +nonzero. + +This macros only needs to be defined if there are cases where +@code{subreg_regno_offset} and @code{subreg_offset_representable_p} +would otherwise wrongly determine that a @code{subreg} can be +represented by an offset to the register number, when in fact such a +@code{subreg} would contain some of the padding not stored in +registers and so not be representable. +@end defmac + +@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode}) +For values of @var{regno} and @var{mode} for which +@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression +returning the greater number of registers required to hold the value +including any padding. In the example above, the value would be four. +@end defmac + +@defmac REGMODE_NATURAL_SIZE (@var{mode}) +Define this macro if the natural size of registers that hold values +of mode @var{mode} is not the word size. It is a C expression that +should give the natural size in bytes for the specified mode. It is +used by the register allocator to try to optimize its results. This +happens for example on SPARC 64-bit where the natural size of +floating-point registers is still 32-bit. +@end defmac + +@defmac HARD_REGNO_MODE_OK (@var{regno}, @var{mode}) +A C expression that is nonzero if it is permissible to store a value +of mode @var{mode} in hard register number @var{regno} (or in several +registers starting with that one). For a machine where all registers +are equivalent, a suitable definition is + +@smallexample +#define HARD_REGNO_MODE_OK(REGNO, MODE) 1 +@end smallexample + +You need not include code to check for the numbers of fixed registers, +because the allocation mechanism considers them to be always occupied. + +@cindex register pairs +On some machines, double-precision values must be kept in even/odd +register pairs. You can implement that by defining this macro to reject +odd register numbers for such modes. + +The minimum requirement for a mode to be OK in a register is that the +@samp{mov@var{mode}} instruction pattern support moves between the +register and other hard register in the same class and that moving a +value into the register and back out not alter it. + +Since the same instruction used to move @code{word_mode} will work for +all narrower integer modes, it is not necessary on any machine for +@code{HARD_REGNO_MODE_OK} to distinguish between these modes, provided +you define patterns @samp{movhi}, etc., to take advantage of this. This +is useful because of the interaction between @code{HARD_REGNO_MODE_OK} +and @code{MODES_TIEABLE_P}; it is very desirable for all integer modes +to be tieable. + +Many machines have special registers for floating point arithmetic. +Often people assume that floating point machine modes are allowed only +in floating point registers. This is not true. Any registers that +can hold integers can safely @emph{hold} a floating point machine +mode, whether or not floating arithmetic can be done on it in those +registers. Integer move instructions can be used to move the values. + +On some machines, though, the converse is true: fixed-point machine +modes may not go in floating registers. This is true if the floating +registers normalize any value stored in them, because storing a +non-floating value there would garble it. In this case, +@code{HARD_REGNO_MODE_OK} should reject fixed-point machine modes in +floating registers. But if the floating registers do not automatically +normalize, if you can store any bit pattern in one and retrieve it +unchanged without a trap, then any machine mode may go in a floating +register, so you can define this macro to say so. + +The primary significance of special floating registers is rather that +they are the registers acceptable in floating point arithmetic +instructions. However, this is of no concern to +@code{HARD_REGNO_MODE_OK}. You handle it by writing the proper +constraints for those instructions. + +On some machines, the floating registers are especially slow to access, +so that it is better to store a value in a stack frame than in such a +register if floating point arithmetic is not being done. As long as the +floating registers are not in class @code{GENERAL_REGS}, they will not +be used unless some pattern's constraint asks for one. +@end defmac + +@defmac HARD_REGNO_RENAME_OK (@var{from}, @var{to}) +A C expression that is nonzero if it is OK to rename a hard register +@var{from} to another hard register @var{to}. + +One common use of this macro is to prevent renaming of a register to +another register that is not saved by a prologue in an interrupt +handler. + +The default is always nonzero. +@end defmac + +@defmac MODES_TIEABLE_P (@var{mode1}, @var{mode2}) +A C expression that is nonzero if a value of mode +@var{mode1} is accessible in mode @var{mode2} without copying. + +If @code{HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and +@code{HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always the same for +any @var{r}, then @code{MODES_TIEABLE_P (@var{mode1}, @var{mode2})} +should be nonzero. If they differ for any @var{r}, you should define +this macro to return zero unless some other mechanism ensures the +accessibility of the value in a narrower mode. + +You should define this macro to return nonzero in as many cases as +possible since doing so will allow GCC to perform better register +allocation. +@end defmac + +@defmac AVOID_CCMODE_COPIES +Define this macro if the compiler should avoid copies to/from @code{CCmode} +registers. You should only define this macro if support for copying to/from +@code{CCmode} is incomplete. +@end defmac + +@node Leaf Functions +@subsection Handling Leaf Functions + +@cindex leaf functions +@cindex functions, leaf +On some machines, a leaf function (i.e., one which makes no calls) can run +more efficiently if it does not make its own register window. Often this +means it is required to receive its arguments in the registers where they +are passed by the caller, instead of the registers where they would +normally arrive. + +The special treatment for leaf functions generally applies only when +other conditions are met; for example, often they may use only those +registers for its own variables and temporaries. We use the term ``leaf +function'' to mean a function that is suitable for this special +handling, so that functions with no calls are not necessarily ``leaf +functions''. + +GCC assigns register numbers before it knows whether the function is +suitable for leaf function treatment. So it needs to renumber the +registers in order to output a leaf function. The following macros +accomplish this. + +@defmac LEAF_REGISTERS +Name of a char vector, indexed by hard register number, which +contains 1 for a register that is allowable in a candidate for leaf +function treatment. + +If leaf function treatment involves renumbering the registers, then the +registers marked here should be the ones before renumbering---those that +GCC would ordinarily allocate. The registers which will actually be +used in the assembler code, after renumbering, should not be marked with 1 +in this vector. + +Define this macro only if the target machine offers a way to optimize +the treatment of leaf functions. +@end defmac + +@defmac LEAF_REG_REMAP (@var{regno}) +A C expression whose value is the register number to which @var{regno} +should be renumbered, when a function is treated as a leaf function. + +If @var{regno} is a register number which should not appear in a leaf +function before renumbering, then the expression should yield @minus{}1, which +will cause the compiler to abort. + +Define this macro only if the target machine offers a way to optimize the +treatment of leaf functions, and registers need to be renumbered to do +this. +@end defmac + +@findex current_function_is_leaf +@findex current_function_uses_only_leaf_regs +@code{TARGET_ASM_FUNCTION_PROLOGUE} and +@code{TARGET_ASM_FUNCTION_EPILOGUE} must usually treat leaf functions +specially. They can test the C variable @code{current_function_is_leaf} +which is nonzero for leaf functions. @code{current_function_is_leaf} is +set prior to local register allocation and is valid for the remaining +compiler passes. They can also test the C variable +@code{current_function_uses_only_leaf_regs} which is nonzero for leaf +functions which only use leaf registers. +@code{current_function_uses_only_leaf_regs} is valid after all passes +that modify the instructions have been run and is only useful if +@code{LEAF_REGISTERS} is defined. +@c changed this to fix overfull. ALSO: why the "it" at the beginning +@c of the next paragraph?! --mew 2feb93 + +@node Stack Registers +@subsection Registers That Form a Stack + +There are special features to handle computers where some of the +``registers'' form a stack. Stack registers are normally written by +pushing onto the stack, and are numbered relative to the top of the +stack. + +Currently, GCC can only handle one group of stack-like registers, and +they must be consecutively numbered. Furthermore, the existing +support for stack-like registers is specific to the 80387 floating +point coprocessor. If you have a new architecture that uses +stack-like registers, you will need to do substantial work on +@file{reg-stack.c} and write your machine description to cooperate +with it, as well as defining these macros. + +@defmac STACK_REGS +Define this if the machine has any stack-like registers. +@end defmac + +@defmac FIRST_STACK_REG +The number of the first stack-like register. This one is the top +of the stack. +@end defmac + +@defmac LAST_STACK_REG +The number of the last stack-like register. This one is the bottom of +the stack. +@end defmac + +@node Register Classes +@section Register Classes +@cindex register class definitions +@cindex class definitions, register + +On many machines, the numbered registers are not all equivalent. +For example, certain registers may not be allowed for indexed addressing; +certain registers may not be allowed in some instructions. These machine +restrictions are described to the compiler using @dfn{register classes}. + +You define a number of register classes, giving each one a name and saying +which of the registers belong to it. Then you can specify register classes +that are allowed as operands to particular instruction patterns. + +@findex ALL_REGS +@findex NO_REGS +In general, each register will belong to several classes. In fact, one +class must be named @code{ALL_REGS} and contain all the registers. Another +class must be named @code{NO_REGS} and contain no registers. Often the +union of two classes will be another class; however, this is not required. + +@findex GENERAL_REGS +One of the classes must be named @code{GENERAL_REGS}. There is nothing +terribly special about the name, but the operand constraint letters +@samp{r} and @samp{g} specify this class. If @code{GENERAL_REGS} is +the same as @code{ALL_REGS}, just define it as a macro which expands +to @code{ALL_REGS}. + +Order the classes so that if class @var{x} is contained in class @var{y} +then @var{x} has a lower class number than @var{y}. + +The way classes other than @code{GENERAL_REGS} are specified in operand +constraints is through machine-dependent operand constraint letters. +You can define such letters to correspond to various classes, then use +them in operand constraints. + +You should define a class for the union of two classes whenever some +instruction allows both classes. For example, if an instruction allows +either a floating point (coprocessor) register or a general register for a +certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS} +which includes both of them. Otherwise you will get suboptimal code. + +You must also specify certain redundant information about the register +classes: for each class, which classes contain it and which ones are +contained in it; for each pair of classes, the largest class contained +in their union. + +When a value occupying several consecutive registers is expected in a +certain class, all the registers used must belong to that class. +Therefore, register classes cannot be used to enforce a requirement for +a register pair to start with an even-numbered register. The way to +specify this requirement is with @code{HARD_REGNO_MODE_OK}. + +Register classes used for input-operands of bitwise-and or shift +instructions have a special requirement: each such class must have, for +each fixed-point machine mode, a subclass whose registers can transfer that +mode to or from memory. For example, on some machines, the operations for +single-byte values (@code{QImode}) are limited to certain registers. When +this is so, each register class that is used in a bitwise-and or shift +instruction must have a subclass consisting of registers from which +single-byte values can be loaded or stored. This is so that +@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return. + +@deftp {Data type} {enum reg_class} +An enumerated type that must be defined with all the register class names +as enumerated values. @code{NO_REGS} must be first. @code{ALL_REGS} +must be the last register class, followed by one more enumerated value, +@code{LIM_REG_CLASSES}, which is not a register class but rather +tells how many classes there are. + +Each register class has a number, which is the value of casting +the class name to type @code{int}. The number serves as an index +in many of the tables described below. +@end deftp + +@defmac N_REG_CLASSES +The number of distinct register classes, defined as follows: + +@smallexample +#define N_REG_CLASSES (int) LIM_REG_CLASSES +@end smallexample +@end defmac + +@defmac REG_CLASS_NAMES +An initializer containing the names of the register classes as C string +constants. These names are used in writing some of the debugging dumps. +@end defmac + +@defmac REG_CLASS_CONTENTS +An initializer containing the contents of the register classes, as integers +which are bit masks. The @var{n}th integer specifies the contents of class +@var{n}. The way the integer @var{mask} is interpreted is that +register @var{r} is in the class if @code{@var{mask} & (1 << @var{r})} is 1. + +When the machine has more than 32 registers, an integer does not suffice. +Then the integers are replaced by sub-initializers, braced groupings containing +several integers. Each sub-initializer must be suitable as an initializer +for the type @code{HARD_REG_SET} which is defined in @file{hard-reg-set.h}. +In this situation, the first integer in each sub-initializer corresponds to +registers 0 through 31, the second integer to registers 32 through 63, and +so on. +@end defmac + +@defmac REGNO_REG_CLASS (@var{regno}) +A C expression whose value is a register class containing hard register +@var{regno}. In general there is more than one such class; choose a class +which is @dfn{minimal}, meaning that no smaller class also contains the +register. +@end defmac + +@defmac BASE_REG_CLASS +A macro whose definition is the name of the class to which a valid +base register must belong. A base register is one used in an address +which is the register value plus a displacement. +@end defmac + +@defmac MODE_BASE_REG_CLASS (@var{mode}) +This is a variation of the @code{BASE_REG_CLASS} macro which allows +the selection of a base register in a mode dependent manner. If +@var{mode} is VOIDmode then it should return the same value as +@code{BASE_REG_CLASS}. +@end defmac + +@defmac MODE_BASE_REG_REG_CLASS (@var{mode}) +A C expression whose value is the register class to which a valid +base register must belong in order to be used in a base plus index +register address. You should define this macro if base plus index +addresses have different requirements than other base register uses. +@end defmac + +@defmac MODE_CODE_BASE_REG_CLASS (@var{mode}, @var{outer_code}, @var{index_code}) +A C expression whose value is the register class to which a valid +base register must belong. @var{outer_code} and @var{index_code} define the +context in which the base register occurs. @var{outer_code} is the code of +the immediately enclosing expression (@code{MEM} for the top level of an +address, @code{ADDRESS} for something that occurs in an +@code{address_operand}). @var{index_code} is the code of the corresponding +index expression if @var{outer_code} is @code{PLUS}; @code{SCRATCH} otherwise. +@end defmac + +@defmac INDEX_REG_CLASS +A macro whose definition is the name of the class to which a valid +index register must belong. An index register is one used in an +address where its value is either multiplied by a scale factor or +added to another register (as well as added to a displacement). +@end defmac + +@defmac REGNO_OK_FOR_BASE_P (@var{num}) +A C expression which is nonzero if register number @var{num} is +suitable for use as a base register in operand addresses. It may be +either a suitable hard register or a pseudo register that has been +allocated such a hard register. +@end defmac + +@defmac REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode}) +A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that +that expression may examine the mode of the memory reference in +@var{mode}. You should define this macro if the mode of the memory +reference affects whether a register may be used as a base register. If +you define this macro, the compiler will use it instead of +@code{REGNO_OK_FOR_BASE_P}. The mode may be @code{VOIDmode} for addresses +that appear outside a @code{MEM}, i.e. as an @code{address_operand}. + +@end defmac + +@defmac REGNO_MODE_OK_FOR_REG_BASE_P (@var{num}, @var{mode}) +A C expression which is nonzero if register number @var{num} is suitable for +use as a base register in base plus index operand addresses, accessing +memory in mode @var{mode}. It may be either a suitable hard register or a +pseudo register that has been allocated such a hard register. You should +define this macro if base plus index addresses have different requirements +than other base register uses. + +Use of this macro is deprecated; please use the more general +@code{REGNO_MODE_CODE_OK_FOR_BASE_P}. +@end defmac + +@defmac REGNO_MODE_CODE_OK_FOR_BASE_P (@var{num}, @var{mode}, @var{outer_code}, @var{index_code}) +A C expression that is just like @code{REGNO_MODE_OK_FOR_BASE_P}, except that +that expression may examine the context in which the register appears in the +memory reference. @var{outer_code} is the code of the immediately enclosing +expression (@code{MEM} if at the top level of the address, @code{ADDRESS} for +something that occurs in an @code{address_operand}). @var{index_code} is the +code of the corresponding index expression if @var{outer_code} is @code{PLUS}; +@code{SCRATCH} otherwise. The mode may be @code{VOIDmode} for addresses +that appear outside a @code{MEM}, i.e. as an @code{address_operand}. +@end defmac + +@defmac REGNO_OK_FOR_INDEX_P (@var{num}) +A C expression which is nonzero if register number @var{num} is +suitable for use as an index register in operand addresses. It may be +either a suitable hard register or a pseudo register that has been +allocated such a hard register. + +The difference between an index register and a base register is that +the index register may be scaled. If an address involves the sum of +two registers, neither one of them scaled, then either one may be +labeled the ``base'' and the other the ``index''; but whichever +labeling is used must fit the machine's constraints of which registers +may serve in each capacity. The compiler will try both labelings, +looking for one that is valid, and will reload one or both registers +only if neither labeling works. +@end defmac + +@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class}) +A C expression that places additional restrictions on the register class +to use when it is necessary to copy value @var{x} into a register in class +@var{class}. The value is a register class; perhaps @var{class}, or perhaps +another, smaller class. On many machines, the following definition is +safe: + +@smallexample +#define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS +@end smallexample + +Sometimes returning a more restrictive class makes better code. For +example, on the 68000, when @var{x} is an integer constant that is in range +for a @samp{moveq} instruction, the value of this macro is always +@code{DATA_REGS} as long as @var{class} includes the data registers. +Requiring a data register guarantees that a @samp{moveq} will be used. + +One case where @code{PREFERRED_RELOAD_CLASS} must not return +@var{class} is if @var{x} is a legitimate constant which cannot be +loaded into some register class. By returning @code{NO_REGS} you can +force @var{x} into a memory location. For example, rs6000 can load +immediate values into general-purpose registers, but does not have an +instruction for loading an immediate value into a floating-point +register, so @code{PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when +@var{x} is a floating-point constant. If the constant can't be loaded +into any kind of register, code generation will be better if +@code{LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead +of using @code{PREFERRED_RELOAD_CLASS}. + +If an insn has pseudos in it after register allocation, reload will go +through the alternatives and call repeatedly @code{PREFERRED_RELOAD_CLASS} +to find the best one. Returning @code{NO_REGS}, in this case, makes +reload add a @code{!} in front of the constraint: the x86 back-end uses +this feature to discourage usage of 387 registers when math is done in +the SSE registers (and vice versa). +@end defmac + +@defmac PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class}) +Like @code{PREFERRED_RELOAD_CLASS}, but for output reloads instead of +input reloads. If you don't define this macro, the default is to use +@var{class}, unchanged. + +You can also use @code{PREFERRED_OUTPUT_RELOAD_CLASS} to discourage +reload from using some alternatives, like @code{PREFERRED_RELOAD_CLASS}. +@end defmac + +@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class}) +A C expression that places additional restrictions on the register class +to use when it is necessary to be able to hold a value of mode +@var{mode} in a reload register for which class @var{class} would +ordinarily be used. + +Unlike @code{PREFERRED_RELOAD_CLASS}, this macro should be used when +there are certain modes that simply can't go in certain reload classes. + +The value is a register class; perhaps @var{class}, or perhaps another, +smaller class. + +Don't define this macro unless the target machine has limitations which +require the macro to do something nontrivial. +@end defmac + +@deftypefn {Target Hook} enum reg_class TARGET_SECONDARY_RELOAD (bool @var{in_p}, rtx @var{x}, enum reg_class @var{reload_class}, enum machine_mode @var{reload_mode}, secondary_reload_info *@var{sri}) +Many machines have some registers that cannot be copied directly to or +from memory or even from other types of registers. An example is the +@samp{MQ} register, which on most machines, can only be copied to or +from general registers, but not memory. Below, we shall be using the +term 'intermediate register' when a move operation cannot be performed +directly, but has to be done by copying the source into the intermediate +register first, and then copying the intermediate register to the +destination. An intermediate register always has the same mode as +source and destination. Since it holds the actual value being copied, +reload might apply optimizations to re-use an intermediate register +and eliding the copy from the source when it can determine that the +intermediate register still holds the required value. + +Another kind of secondary reload is required on some machines which +allow copying all registers to and from memory, but require a scratch +register for stores to some memory locations (e.g., those with symbolic +address on the RT, and those with certain symbolic address on the SPARC +when compiling PIC)@. Scratch registers need not have the same mode +as the value being copied, and usually hold a different value that +that being copied. Special patterns in the md file are needed to +describe how the copy is performed with the help of the scratch register; +these patterns also describe the number, register class(es) and mode(s) +of the scratch register(s). + +In some cases, both an intermediate and a scratch register are required. + +For input reloads, this target hook is called with nonzero @var{in_p}, +and @var{x} is an rtx that needs to be copied to a register in of class +@var{reload_class} in @var{reload_mode}. For output reloads, this target +hook is called with zero @var{in_p}, and a register of class @var{reload_mode} +needs to be copied to rtx @var{x} in @var{reload_mode}. + +If copying a register of @var{reload_class} from/to @var{x} requires +an intermediate register, the hook @code{secondary_reload} should +return the register class required for this intermediate register. +If no intermediate register is required, it should return NO_REGS. +If more than one intermediate register is required, describe the one +that is closest in the copy chain to the reload register. + +If scratch registers are needed, you also have to describe how to +perform the copy from/to the reload register to/from this +closest intermediate register. Or if no intermediate register is +required, but still a scratch register is needed, describe the +copy from/to the reload register to/from the reload operand @var{x}. + +You do this by setting @code{sri->icode} to the instruction code of a pattern +in the md file which performs the move. Operands 0 and 1 are the output +and input of this copy, respectively. Operands from operand 2 onward are +for scratch operands. These scratch operands must have a mode, and a +single-register-class +@c [later: or memory] +output constraint. + +When an intermediate register is used, the @code{secondary_reload} +hook will be called again to determine how to copy the intermediate +register to/from the reload operand @var{x}, so your hook must also +have code to handle the register class of the intermediate operand. + +@c [For later: maybe we'll allow multi-alternative reload patterns - +@c the port maintainer could name a mov<mode> pattern that has clobbers - +@c and match the constraints of input and output to determine the required +@c alternative. A restriction would be that constraints used to match +@c against reloads registers would have to be written as register class +@c constraints, or we need a new target macro / hook that tells us if an +@c arbitrary constraint can match an unknown register of a given class. +@c Such a macro / hook would also be useful in other places.] + + +@var{x} might be a pseudo-register or a @code{subreg} of a +pseudo-register, which could either be in a hard register or in memory. +Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is +in memory and the hard register number if it is in a register. + +Scratch operands in memory (constraint @code{"=m"} / @code{"=&m"}) are +currently not supported. For the time being, you will have to continue +to use @code{SECONDARY_MEMORY_NEEDED} for that purpose. + +@code{copy_cost} also uses this target hook to find out how values are +copied. If you want it to include some extra cost for the need to allocate +(a) scratch register(s), set @code{sri->extra_cost} to the additional cost. +Or if two dependent moves are supposed to have a lower cost than the sum +of the individual moves due to expected fortuitous scheduling and/or special +forwarding logic, you can set @code{sri->extra_cost} to a negative amount. +@end deftypefn + +@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x}) +@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x}) +@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x}) +These macros are obsolete, new ports should use the target hook +@code{TARGET_SECONDARY_RELOAD} instead. + +These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD} +target hook. Older ports still define these macros to indicate to the +reload phase that it may +need to allocate at least one register for a reload in addition to the +register to contain the data. Specifically, if copying @var{x} to a +register @var{class} in @var{mode} requires an intermediate register, +you were supposed to define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the +largest register class all of whose registers can be used as +intermediate registers or scratch registers. + +If copying a register @var{class} in @var{mode} to @var{x} requires an +intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS} +was supposed to be defined be defined to return the largest register +class required. If the +requirements for input and output reloads were the same, the macro +@code{SECONDARY_RELOAD_CLASS} should have been used instead of defining both +macros identically. + +The values returned by these macros are often @code{GENERAL_REGS}. +Return @code{NO_REGS} if no spare register is needed; i.e., if @var{x} +can be directly copied to or from a register of @var{class} in +@var{mode} without requiring a scratch register. Do not define this +macro if it would always return @code{NO_REGS}. + +If a scratch register is required (either with or without an +intermediate register), you were supposed to define patterns for +@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required +(@pxref{Standard Names}. These patterns, which were normally +implemented with a @code{define_expand}, should be similar to the +@samp{mov@var{m}} patterns, except that operand 2 is the scratch +register. + +These patterns need constraints for the reload register and scratch +register that +contain a single register class. If the original reload register (whose +class is @var{class}) can meet the constraint given in the pattern, the +value returned by these macros is used for the class of the scratch +register. Otherwise, two additional reload registers are required. +Their classes are obtained from the constraints in the insn pattern. + +@var{x} might be a pseudo-register or a @code{subreg} of a +pseudo-register, which could either be in a hard register or in memory. +Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is +in memory and the hard register number if it is in a register. + +These macros should not be used in the case where a particular class of +registers can only be copied to memory and not to another class of +registers. In that case, secondary reload registers are not needed and +would not be helpful. Instead, a stack location must be used to perform +the copy and the @code{mov@var{m}} pattern should use memory as an +intermediate storage. This case often occurs between floating-point and +general registers. +@end defmac + +@defmac SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m}) +Certain machines have the property that some registers cannot be copied +to some other registers without using memory. Define this macro on +those machines to be a C expression that is nonzero if objects of mode +@var{m} in registers of @var{class1} can only be copied to registers of +class @var{class2} by storing a register of @var{class1} into memory +and loading that memory location into a register of @var{class2}. + +Do not define this macro if its value would always be zero. +@end defmac + +@defmac SECONDARY_MEMORY_NEEDED_RTX (@var{mode}) +Normally when @code{SECONDARY_MEMORY_NEEDED} is defined, the compiler +allocates a stack slot for a memory location needed for register copies. +If this macro is defined, the compiler instead uses the memory location +defined by this macro. + +Do not define this macro if you do not define +@code{SECONDARY_MEMORY_NEEDED}. +@end defmac + +@defmac SECONDARY_MEMORY_NEEDED_MODE (@var{mode}) +When the compiler needs a secondary memory location to copy between two +registers of mode @var{mode}, it normally allocates sufficient memory to +hold a quantity of @code{BITS_PER_WORD} bits and performs the store and +load operations in a mode that many bits wide and whose class is the +same as that of @var{mode}. + +This is right thing to do on most machines because it ensures that all +bits of the register are copied and prevents accesses to the registers +in a narrower mode, which some machines prohibit for floating-point +registers. + +However, this default behavior is not correct on some machines, such as +the DEC Alpha, that store short integers in floating-point registers +differently than in integer registers. On those machines, the default +widening will not work correctly and you must define this macro to +suppress that widening in some cases. See the file @file{alpha.h} for +details. + +Do not define this macro if you do not define +@code{SECONDARY_MEMORY_NEEDED} or if widening @var{mode} to a mode that +is @code{BITS_PER_WORD} bits wide is correct for your machine. +@end defmac + +@defmac SMALL_REGISTER_CLASSES +On some machines, it is risky to let hard registers live across arbitrary +insns. Typically, these machines have instructions that require values +to be in specific registers (like an accumulator), and reload will fail +if the required hard register is used for another purpose across such an +insn. + +Define @code{SMALL_REGISTER_CLASSES} to be an expression with a nonzero +value on these machines. When this macro has a nonzero value, the +compiler will try to minimize the lifetime of hard registers. + +It is always safe to define this macro with a nonzero value, but if you +unnecessarily define it, you will reduce the amount of optimizations +that can be performed in some cases. If you do not define this macro +with a nonzero value when it is required, the compiler will run out of +spill registers and print a fatal error message. For most machines, you +should not define this macro at all. +@end defmac + +@defmac CLASS_LIKELY_SPILLED_P (@var{class}) +A C expression whose value is nonzero if pseudos that have been assigned +to registers of class @var{class} would likely be spilled because +registers of @var{class} are needed for spill registers. + +The default value of this macro returns 1 if @var{class} has exactly one +register and zero otherwise. On most machines, this default should be +used. Only define this macro to some other expression if pseudos +allocated by @file{local-alloc.c} end up in memory because their hard +registers were needed for spill registers. If this macro returns nonzero +for those classes, those pseudos will only be allocated by +@file{global.c}, which knows how to reallocate the pseudo to another +register. If there would not be another register available for +reallocation, you should not change the definition of this macro since +the only effect of such a definition would be to slow down register +allocation. +@end defmac + +@defmac CLASS_MAX_NREGS (@var{class}, @var{mode}) +A C expression for the maximum number of consecutive registers +of class @var{class} needed to hold a value of mode @var{mode}. + +This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact, +the value of the macro @code{CLASS_MAX_NREGS (@var{class}, @var{mode})} +should be the maximum value of @code{HARD_REGNO_NREGS (@var{regno}, +@var{mode})} for all @var{regno} values in the class @var{class}. + +This macro helps control the handling of multiple-word values +in the reload pass. +@end defmac + +@defmac CANNOT_CHANGE_MODE_CLASS (@var{from}, @var{to}, @var{class}) +If defined, a C expression that returns nonzero for a @var{class} for which +a change from mode @var{from} to mode @var{to} is invalid. + +For the example, loading 32-bit integer or floating-point objects into +floating-point registers on the Alpha extends them to 64 bits. +Therefore loading a 64-bit object and then storing it as a 32-bit object +does not store the low-order 32 bits, as would be the case for a normal +register. Therefore, @file{alpha.h} defines @code{CANNOT_CHANGE_MODE_CLASS} +as below: + +@smallexample +#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \ + (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \ + ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0) +@end smallexample +@end defmac + +@node Old Constraints +@section Obsolete Macros for Defining Constraints +@cindex defining constraints, obsolete method +@cindex constraints, defining, obsolete method + +Machine-specific constraints can be defined with these macros instead +of the machine description constructs described in @ref{Define +Constraints}. This mechanism is obsolete. New ports should not use +it; old ports should convert to the new mechanism. + +@defmac CONSTRAINT_LEN (@var{char}, @var{str}) +For the constraint at the start of @var{str}, which starts with the letter +@var{c}, return the length. This allows you to have register class / +constant / extra constraints that are longer than a single letter; +you don't need to define this macro if you can do with single-letter +constraints only. The definition of this macro should use +DEFAULT_CONSTRAINT_LEN for all the characters that you don't want +to handle specially. +There are some sanity checks in genoutput.c that check the constraint lengths +for the md file, so you can also use this macro to help you while you are +transitioning from a byzantine single-letter-constraint scheme: when you +return a negative length for a constraint you want to re-use, genoutput +will complain about every instance where it is used in the md file. +@end defmac + +@defmac REG_CLASS_FROM_LETTER (@var{char}) +A C expression which defines the machine-dependent operand constraint +letters for register classes. If @var{char} is such a letter, the +value should be the register class corresponding to it. Otherwise, +the value should be @code{NO_REGS}. The register letter @samp{r}, +corresponding to class @code{GENERAL_REGS}, will not be passed +to this macro; you do not need to handle it. +@end defmac + +@defmac REG_CLASS_FROM_CONSTRAINT (@var{char}, @var{str}) +Like @code{REG_CLASS_FROM_LETTER}, but you also get the constraint string +passed in @var{str}, so that you can use suffixes to distinguish between +different variants. +@end defmac + +@defmac CONST_OK_FOR_LETTER_P (@var{value}, @var{c}) +A C expression that defines the machine-dependent operand constraint +letters (@samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}) that specify +particular ranges of integer values. If @var{c} is one of those +letters, the expression should check that @var{value}, an integer, is in +the appropriate range and return 1 if so, 0 otherwise. If @var{c} is +not one of those letters, the value should be 0 regardless of +@var{value}. +@end defmac + +@defmac CONST_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str}) +Like @code{CONST_OK_FOR_LETTER_P}, but you also get the constraint +string passed in @var{str}, so that you can use suffixes to distinguish +between different variants. +@end defmac + +@defmac CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c}) +A C expression that defines the machine-dependent operand constraint +letters that specify particular ranges of @code{const_double} values +(@samp{G} or @samp{H}). + +If @var{c} is one of those letters, the expression should check that +@var{value}, an RTX of code @code{const_double}, is in the appropriate +range and return 1 if so, 0 otherwise. If @var{c} is not one of those +letters, the value should be 0 regardless of @var{value}. + +@code{const_double} is used for all floating-point constants and for +@code{DImode} fixed-point constants. A given letter can accept either +or both kinds of values. It can use @code{GET_MODE} to distinguish +between these kinds. +@end defmac + +@defmac CONST_DOUBLE_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str}) +Like @code{CONST_DOUBLE_OK_FOR_LETTER_P}, but you also get the constraint +string passed in @var{str}, so that you can use suffixes to distinguish +between different variants. +@end defmac + +@defmac EXTRA_CONSTRAINT (@var{value}, @var{c}) +A C expression that defines the optional machine-dependent constraint +letters that can be used to segregate specific types of operands, usually +memory references, for the target machine. Any letter that is not +elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER} / +@code{REG_CLASS_FROM_CONSTRAINT} +may be used. Normally this macro will not be defined. + +If it is required for a particular target machine, it should return 1 +if @var{value} corresponds to the operand type represented by the +constraint letter @var{c}. If @var{c} is not defined as an extra +constraint, the value returned should be 0 regardless of @var{value}. + +For example, on the ROMP, load instructions cannot have their output +in r0 if the memory reference contains a symbolic address. Constraint +letter @samp{Q} is defined as representing a memory address that does +@emph{not} contain a symbolic address. An alternative is specified with +a @samp{Q} constraint on the input and @samp{r} on the output. The next +alternative specifies @samp{m} on the input and a register class that +does not include r0 on the output. +@end defmac + +@defmac EXTRA_CONSTRAINT_STR (@var{value}, @var{c}, @var{str}) +Like @code{EXTRA_CONSTRAINT}, but you also get the constraint string passed +in @var{str}, so that you can use suffixes to distinguish between different +variants. +@end defmac + +@defmac EXTRA_MEMORY_CONSTRAINT (@var{c}, @var{str}) +A C expression that defines the optional machine-dependent constraint +letters, amongst those accepted by @code{EXTRA_CONSTRAINT}, that should +be treated like memory constraints by the reload pass. + +It should return 1 if the operand type represented by the constraint +at the start of @var{str}, the first letter of which is the letter @var{c}, + comprises a subset of all memory references including +all those whose address is simply a base register. This allows the reload +pass to reload an operand, if it does not directly correspond to the operand +type of @var{c}, by copying its address into a base register. + +For example, on the S/390, some instructions do not accept arbitrary +memory references, but only those that do not make use of an index +register. The constraint letter @samp{Q} is defined via +@code{EXTRA_CONSTRAINT} as representing a memory address of this type. +If the letter @samp{Q} is marked as @code{EXTRA_MEMORY_CONSTRAINT}, +a @samp{Q} constraint can handle any memory operand, because the +reload pass knows it can be reloaded by copying the memory address +into a base register if required. This is analogous to the way +a @samp{o} constraint can handle any memory operand. +@end defmac + +@defmac EXTRA_ADDRESS_CONSTRAINT (@var{c}, @var{str}) +A C expression that defines the optional machine-dependent constraint +letters, amongst those accepted by @code{EXTRA_CONSTRAINT} / +@code{EXTRA_CONSTRAINT_STR}, that should +be treated like address constraints by the reload pass. + +It should return 1 if the operand type represented by the constraint +at the start of @var{str}, which starts with the letter @var{c}, comprises +a subset of all memory addresses including +all those that consist of just a base register. This allows the reload +pass to reload an operand, if it does not directly correspond to the operand +type of @var{str}, by copying it into a base register. + +Any constraint marked as @code{EXTRA_ADDRESS_CONSTRAINT} can only +be used with the @code{address_operand} predicate. It is treated +analogously to the @samp{p} constraint. +@end defmac + +@node Stack and Calling +@section Stack Layout and Calling Conventions +@cindex calling conventions + +@c prevent bad page break with this line +This describes the stack layout and calling conventions. + +@menu +* Frame Layout:: +* Exception Handling:: +* Stack Checking:: +* Frame Registers:: +* Elimination:: +* Stack Arguments:: +* Register Arguments:: +* Scalar Return:: +* Aggregate Return:: +* Caller Saves:: +* Function Entry:: +* Profiling:: +* Tail Calls:: +* Stack Smashing Protection:: +@end menu + +@node Frame Layout +@subsection Basic Stack Layout +@cindex stack frame layout +@cindex frame layout + +@c prevent bad page break with this line +Here is the basic stack layout. + +@defmac STACK_GROWS_DOWNWARD +Define this macro if pushing a word onto the stack moves the stack +pointer to a smaller address. + +When we say, ``define this macro if @dots{}'', it means that the +compiler checks this macro only with @code{#ifdef} so the precise +definition used does not matter. +@end defmac + +@defmac STACK_PUSH_CODE +This macro defines the operation used when something is pushed +on the stack. In RTL, a push operation will be +@code{(set (mem (STACK_PUSH_CODE (reg sp))) @dots{})} + +The choices are @code{PRE_DEC}, @code{POST_DEC}, @code{PRE_INC}, +and @code{POST_INC}. Which of these is correct depends on +the stack direction and on whether the stack pointer points +to the last item on the stack or whether it points to the +space for the next item on the stack. + +The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is +defined, which is almost always right, and @code{PRE_INC} otherwise, +which is often wrong. +@end defmac + +@defmac FRAME_GROWS_DOWNWARD +Define this macro to nonzero value if the addresses of local variable slots +are at negative offsets from the frame pointer. +@end defmac + +@defmac ARGS_GROW_DOWNWARD +Define this macro if successive arguments to a function occupy decreasing +addresses on the stack. +@end defmac + +@defmac STARTING_FRAME_OFFSET +Offset from the frame pointer to the first local variable slot to be allocated. + +If @code{FRAME_GROWS_DOWNWARD}, find the next slot's offset by +subtracting the first slot's length from @code{STARTING_FRAME_OFFSET}. +Otherwise, it is found by adding the length of the first slot to the +value @code{STARTING_FRAME_OFFSET}. +@c i'm not sure if the above is still correct.. had to change it to get +@c rid of an overfull. --mew 2feb93 +@end defmac + +@defmac STACK_ALIGNMENT_NEEDED +Define to zero to disable final alignment of the stack during reload. +The nonzero default for this macro is suitable for most ports. + +On ports where @code{STARTING_FRAME_OFFSET} is nonzero or where there +is a register save block following the local block that doesn't require +alignment to @code{STACK_BOUNDARY}, it may be beneficial to disable +stack alignment and do it in the backend. +@end defmac + +@defmac STACK_POINTER_OFFSET +Offset from the stack pointer register to the first location at which +outgoing arguments are placed. If not specified, the default value of +zero is used. This is the proper value for most machines. + +If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above +the first location at which outgoing arguments are placed. +@end defmac + +@defmac FIRST_PARM_OFFSET (@var{fundecl}) +Offset from the argument pointer register to the first argument's +address. On some machines it may depend on the data type of the +function. + +If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above +the first argument's address. +@end defmac + +@defmac STACK_DYNAMIC_OFFSET (@var{fundecl}) +Offset from the stack pointer register to an item dynamically allocated +on the stack, e.g., by @code{alloca}. + +The default value for this macro is @code{STACK_POINTER_OFFSET} plus the +length of the outgoing arguments. The default is correct for most +machines. See @file{function.c} for details. +@end defmac + +@defmac INITIAL_FRAME_ADDRESS_RTX +A C expression whose value is RTL representing the address of the initial +stack frame. This address is passed to @code{RETURN_ADDR_RTX} and +@code{DYNAMIC_CHAIN_ADDRESS}. If you don't define this macro, a reasonable +default value will be used. Define this macro in order to make frame pointer +elimination work in the presence of @code{__builtin_frame_address (count)} and +@code{__builtin_return_address (count)} for @code{count} not equal to zero. +@end defmac + +@defmac DYNAMIC_CHAIN_ADDRESS (@var{frameaddr}) +A C expression whose value is RTL representing the address in a stack +frame where the pointer to the caller's frame is stored. Assume that +@var{frameaddr} is an RTL expression for the address of the stack frame +itself. + +If you don't define this macro, the default is to return the value +of @var{frameaddr}---that is, the stack frame address is also the +address of the stack word that points to the previous frame. +@end defmac + +@defmac SETUP_FRAME_ADDRESSES +If defined, a C expression that produces the machine-specific code to +setup the stack so that arbitrary frames can be accessed. For example, +on the SPARC, we must flush all of the register windows to the stack +before we can access arbitrary stack frames. You will seldom need to +define this macro. +@end defmac + +@deftypefn {Target Hook} bool TARGET_BUILTIN_SETJMP_FRAME_VALUE () +This target hook should return an rtx that is used to store +the address of the current frame into the built in @code{setjmp} buffer. +The default value, @code{virtual_stack_vars_rtx}, is correct for most +machines. One reason you may need to define this target hook is if +@code{hard_frame_pointer_rtx} is the appropriate value on your machine. +@end deftypefn + +@defmac FRAME_ADDR_RTX (@var{frameaddr}) +A C expression whose value is RTL representing the value of the frame +address for the current frame. @var{frameaddr} is the frame pointer +of the current frame. This is used for __builtin_frame_address. +You need only define this macro if the frame address is not the same +as the frame pointer. Most machines do not need to define it. +@end defmac + +@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr}) +A C expression whose value is RTL representing the value of the return +address for the frame @var{count} steps up from the current frame, after +the prologue. @var{frameaddr} is the frame pointer of the @var{count} +frame, or the frame pointer of the @var{count} @minus{} 1 frame if +@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is defined. + +The value of the expression must always be the correct address when +@var{count} is zero, but may be @code{NULL_RTX} if there is not way to +determine the return address of other frames. +@end defmac + +@defmac RETURN_ADDR_IN_PREVIOUS_FRAME +Define this if the return address of a particular stack frame is accessed +from the frame pointer of the previous stack frame. +@end defmac + +@defmac INCOMING_RETURN_ADDR_RTX +A C expression whose value is RTL representing the location of the +incoming return address at the beginning of any function, before the +prologue. This RTL is either a @code{REG}, indicating that the return +value is saved in @samp{REG}, or a @code{MEM} representing a location in +the stack. + +You only need to define this macro if you want to support call frame +debugging information like that provided by DWARF 2. + +If this RTL is a @code{REG}, you should also define +@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}. +@end defmac + +@defmac DWARF_ALT_FRAME_RETURN_COLUMN +A C expression whose value is an integer giving a DWARF 2 column +number that may be used as an alternate return column. This should +be defined only if @code{DWARF_FRAME_RETURN_COLUMN} is set to a +general register, but an alternate column needs to be used for +signal frames. +@end defmac + +@defmac DWARF_ZERO_REG +A C expression whose value is an integer giving a DWARF 2 register +number that is considered to always have the value zero. This should +only be defined if the target has an architected zero register, and +someone decided it was a good idea to use that register number to +terminate the stack backtrace. New ports should avoid this. +@end defmac + +@deftypefn {Target Hook} void TARGET_DWARF_HANDLE_FRAME_UNSPEC (const char *@var{label}, rtx @var{pattern}, int @var{index}) +This target hook allows the backend to emit frame-related insns that +contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging +info engine will invoke it on insns of the form +@smallexample +(set (reg) (unspec [...] UNSPEC_INDEX)) +@end smallexample +and +@smallexample +(set (reg) (unspec_volatile [...] UNSPECV_INDEX)). +@end smallexample +to let the backend emit the call frame instructions. @var{label} is +the CFI label attached to the insn, @var{pattern} is the pattern of +the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}. +@end deftypefn + +@defmac INCOMING_FRAME_SP_OFFSET +A C expression whose value is an integer giving the offset, in bytes, +from the value of the stack pointer register to the top of the stack +frame at the beginning of any function, before the prologue. The top of +the frame is defined to be the value of the stack pointer in the +previous frame, just before the call instruction. + +You only need to define this macro if you want to support call frame +debugging information like that provided by DWARF 2. +@end defmac + +@defmac ARG_POINTER_CFA_OFFSET (@var{fundecl}) +A C expression whose value is an integer giving the offset, in bytes, +from the argument pointer to the canonical frame address (cfa). The +final value should coincide with that calculated by +@code{INCOMING_FRAME_SP_OFFSET}. Which is unfortunately not usable +during virtual register instantiation. + +The default value for this macro is @code{FIRST_PARM_OFFSET (fundecl)}, +which is correct for most machines; in general, the arguments are found +immediately before the stack frame. Note that this is not the case on +some targets that save registers into the caller's frame, such as SPARC +and rs6000, and so such targets need to define this macro. + +You only need to define this macro if the default is incorrect, and you +want to support call frame debugging information like that provided by +DWARF 2. +@end defmac + +@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl}) +If defined, a C expression whose value is an integer giving the offset +in bytes from the frame pointer to the canonical frame address (cfa). +The final value should coincide with that calculated by +@code{INCOMING_FRAME_SP_OFFSET}. + +Normally the CFA is calculated as an offset from the argument pointer, +via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is +variable due to the ABI, this may not be possible. If this macro is +defined, it implies that the virtual register instantiation should be +based on the frame pointer instead of the argument pointer. Only one +of @code{FRAME_POINTER_CFA_OFFSET} and @code{ARG_POINTER_CFA_OFFSET} +should be defined. +@end defmac + +@defmac CFA_FRAME_BASE_OFFSET (@var{fundecl}) +If defined, a C expression whose value is an integer giving the offset +in bytes from the canonical frame address (cfa) to the frame base used +in DWARF 2 debug information. The default is zero. A different value +may reduce the size of debug information on some ports. +@end defmac + +@node Exception Handling +@subsection Exception Handling Support +@cindex exception handling + +@defmac EH_RETURN_DATA_REGNO (@var{N}) +A C expression whose value is the @var{N}th register number used for +data by exception handlers, or @code{INVALID_REGNUM} if fewer than +@var{N} registers are usable. + +The exception handling library routines communicate with the exception +handlers via a set of agreed upon registers. Ideally these registers +should be call-clobbered; it is possible to use call-saved registers, +but may negatively impact code size. The target must support at least +2 data registers, but should define 4 if there are enough free registers. + +You must define this macro if you want to support call frame exception +handling like that provided by DWARF 2. +@end defmac + +@defmac EH_RETURN_STACKADJ_RTX +A C expression whose value is RTL representing a location in which +to store a stack adjustment to be applied before function return. +This is used to unwind the stack to an exception handler's call frame. +It will be assigned zero on code paths that return normally. + +Typically this is a call-clobbered hard register that is otherwise +untouched by the epilogue, but could also be a stack slot. + +Do not define this macro if the stack pointer is saved and restored +by the regular prolog and epilog code in the call frame itself; in +this case, the exception handling library routines will update the +stack location to be restored in place. Otherwise, you must define +this macro if you want to support call frame exception handling like +that provided by DWARF 2. +@end defmac + +@defmac EH_RETURN_HANDLER_RTX +A C expression whose value is RTL representing a location in which +to store the address of an exception handler to which we should +return. It will not be assigned on code paths that return normally. + +Typically this is the location in the call frame at which the normal +return address is stored. For targets that return by popping an +address off the stack, this might be a memory address just below +the @emph{target} call frame rather than inside the current call +frame. If defined, @code{EH_RETURN_STACKADJ_RTX} will have already +been assigned, so it may be used to calculate the location of the +target call frame. + +Some targets have more complex requirements than storing to an +address calculable during initial code generation. In that case +the @code{eh_return} instruction pattern should be used instead. + +If you want to support call frame exception handling, you must +define either this macro or the @code{eh_return} instruction pattern. +@end defmac + +@defmac RETURN_ADDR_OFFSET +If defined, an integer-valued C expression for which rtl will be generated +to add it to the exception handler address before it is searched in the +exception handling tables, and to subtract it again from the address before +using it to return to the exception handler. +@end defmac + +@defmac ASM_PREFERRED_EH_DATA_FORMAT (@var{code}, @var{global}) +This macro chooses the encoding of pointers embedded in the exception +handling sections. If at all possible, this should be defined such +that the exception handling section will not require dynamic relocations, +and so may be read-only. + +@var{code} is 0 for data, 1 for code labels, 2 for function pointers. +@var{global} is true if the symbol may be affected by dynamic relocations. +The macro should return a combination of the @code{DW_EH_PE_*} defines +as found in @file{dwarf2.h}. + +If this macro is not defined, pointers will not be encoded but +represented directly. +@end defmac + +@defmac ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done}) +This macro allows the target to emit whatever special magic is required +to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}. +Generic code takes care of pc-relative and indirect encodings; this must +be defined if the target uses text-relative or data-relative encodings. + +This is a C statement that branches to @var{done} if the format was +handled. @var{encoding} is the format chosen, @var{size} is the number +of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF} +to be emitted. +@end defmac + +@defmac MD_UNWIND_SUPPORT +A string specifying a file to be #include'd in unwind-dw2.c. The file +so included typically defines @code{MD_FALLBACK_FRAME_STATE_FOR}. +@end defmac + +@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs}) +This macro allows the target to add cpu and operating system specific +code to the call-frame unwinder for use when there is no unwind data +available. The most common reason to implement this macro is to unwind +through signal frames. + +This macro is called from @code{uw_frame_state_for} in @file{unwind-dw2.c} +and @file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context}; +@var{fs} is an @code{_Unwind_FrameState}. Examine @code{context->ra} +for the address of the code being executed and @code{context->cfa} for +the stack pointer value. If the frame can be decoded, the register save +addresses should be updated in @var{fs} and the macro should evaluate to +@code{_URC_NO_REASON}. If the frame cannot be decoded, the macro should +evaluate to @code{_URC_END_OF_STACK}. + +For proper signal handling in Java this macro is accompanied by +@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers. +@end defmac + +@defmac MD_HANDLE_UNWABI (@var{context}, @var{fs}) +This macro allows the target to add operating system specific code to the +call-frame unwinder to handle the IA-64 @code{.unwabi} unwinding directive, +usually used for signal or interrupt frames. + +This macro is called from @code{uw_update_context} in @file{unwind-ia64.c}. +@var{context} is an @code{_Unwind_Context}; +@var{fs} is an @code{_Unwind_FrameState}. Examine @code{fs->unwabi} +for the abi and context in the @code{.unwabi} directive. If the +@code{.unwabi} directive can be handled, the register save addresses should +be updated in @var{fs}. +@end defmac + +@defmac TARGET_USES_WEAK_UNWIND_INFO +A C expression that evaluates to true if the target requires unwind +info to be given comdat linkage. Define it to be @code{1} if comdat +linkage is necessary. The default is @code{0}. +@end defmac + +@node Stack Checking +@subsection Specifying How Stack Checking is Done + +GCC will check that stack references are within the boundaries of +the stack, if the @option{-fstack-check} is specified, in one of three ways: + +@enumerate +@item +If the value of the @code{STACK_CHECK_BUILTIN} macro is nonzero, GCC +will assume that you have arranged for stack checking to be done at +appropriate places in the configuration files, e.g., in +@code{TARGET_ASM_FUNCTION_PROLOGUE}. GCC will do not other special +processing. + +@item +If @code{STACK_CHECK_BUILTIN} is zero and you defined a named pattern +called @code{check_stack} in your @file{md} file, GCC will call that +pattern with one argument which is the address to compare the stack +value against. You must arrange for this pattern to report an error if +the stack pointer is out of range. + +@item +If neither of the above are true, GCC will generate code to periodically +``probe'' the stack pointer using the values of the macros defined below. +@end enumerate + +Normally, you will use the default values of these macros, so GCC +will use the third approach. + +@defmac STACK_CHECK_BUILTIN +A nonzero value if stack checking is done by the configuration files in a +machine-dependent manner. You should define this macro if stack checking +is require by the ABI of your machine or if you would like to have to stack +checking in some more efficient way than GCC's portable approach. +The default value of this macro is zero. +@end defmac + +@defmac STACK_CHECK_PROBE_INTERVAL +An integer representing the interval at which GCC must generate stack +probe instructions. You will normally define this macro to be no larger +than the size of the ``guard pages'' at the end of a stack area. The +default value of 4096 is suitable for most systems. +@end defmac + +@defmac STACK_CHECK_PROBE_LOAD +A integer which is nonzero if GCC should perform the stack probe +as a load instruction and zero if GCC should use a store instruction. +The default is zero, which is the most efficient choice on most systems. +@end defmac + +@defmac STACK_CHECK_PROTECT +The number of bytes of stack needed to recover from a stack overflow, +for languages where such a recovery is supported. The default value of +75 words should be adequate for most machines. +@end defmac + +@defmac STACK_CHECK_MAX_FRAME_SIZE +The maximum size of a stack frame, in bytes. GCC will generate probe +instructions in non-leaf functions to ensure at least this many bytes of +stack are available. If a stack frame is larger than this size, stack +checking will not be reliable and GCC will issue a warning. The +default is chosen so that GCC only generates one instruction on most +systems. You should normally not change the default value of this macro. +@end defmac + +@defmac STACK_CHECK_FIXED_FRAME_SIZE +GCC uses this value to generate the above warning message. It +represents the amount of fixed frame used by a function, not including +space for any callee-saved registers, temporaries and user variables. +You need only specify an upper bound for this amount and will normally +use the default of four words. +@end defmac + +@defmac STACK_CHECK_MAX_VAR_SIZE +The maximum size, in bytes, of an object that GCC will place in the +fixed area of the stack frame when the user specifies +@option{-fstack-check}. +GCC computed the default from the values of the above macros and you will +normally not need to override that default. +@end defmac + +@need 2000 +@node Frame Registers +@subsection Registers That Address the Stack Frame + +@c prevent bad page break with this line +This discusses registers that address the stack frame. + +@defmac STACK_POINTER_REGNUM +The register number of the stack pointer register, which must also be a +fixed register according to @code{FIXED_REGISTERS}. On most machines, +the hardware determines which register this is. +@end defmac + +@defmac FRAME_POINTER_REGNUM +The register number of the frame pointer register, which is used to +access automatic variables in the stack frame. On some machines, the +hardware determines which register this is. On other machines, you can +choose any register you wish for this purpose. +@end defmac + +@defmac HARD_FRAME_POINTER_REGNUM +On some machines the offset between the frame pointer and starting +offset of the automatic variables is not known until after register +allocation has been done (for example, because the saved registers are +between these two locations). On those machines, define +@code{FRAME_POINTER_REGNUM} the number of a special, fixed register to +be used internally until the offset is known, and define +@code{HARD_FRAME_POINTER_REGNUM} to be the actual hard register number +used for the frame pointer. + +You should define this macro only in the very rare circumstances when it +is not possible to calculate the offset between the frame pointer and +the automatic variables until after register allocation has been +completed. When this macro is defined, you must also indicate in your +definition of @code{ELIMINABLE_REGS} how to eliminate +@code{FRAME_POINTER_REGNUM} into either @code{HARD_FRAME_POINTER_REGNUM} +or @code{STACK_POINTER_REGNUM}. + +Do not define this macro if it would be the same as +@code{FRAME_POINTER_REGNUM}. +@end defmac + +@defmac ARG_POINTER_REGNUM +The register number of the arg pointer register, which is used to access +the function's argument list. On some machines, this is the same as the +frame pointer register. On some machines, the hardware determines which +register this is. On other machines, you can choose any register you +wish for this purpose. If this is not the same register as the frame +pointer register, then you must mark it as a fixed register according to +@code{FIXED_REGISTERS}, or arrange to be able to eliminate it +(@pxref{Elimination}). +@end defmac + +@defmac RETURN_ADDRESS_POINTER_REGNUM +The register number of the return address pointer register, which is used to +access the current function's return address from the stack. On some +machines, the return address is not at a fixed offset from the frame +pointer or stack pointer or argument pointer. This register can be defined +to point to the return address on the stack, and then be converted by +@code{ELIMINABLE_REGS} into either the frame pointer or stack pointer. + +Do not define this macro unless there is no other way to get the return +address from the stack. +@end defmac + +@defmac STATIC_CHAIN_REGNUM +@defmacx STATIC_CHAIN_INCOMING_REGNUM +Register numbers used for passing a function's static chain pointer. If +register windows are used, the register number as seen by the called +function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register +number as seen by the calling function is @code{STATIC_CHAIN_REGNUM}. If +these registers are the same, @code{STATIC_CHAIN_INCOMING_REGNUM} need +not be defined. + +The static chain register need not be a fixed register. + +If the static chain is passed in memory, these macros should not be +defined; instead, the next two macros should be defined. +@end defmac + +@defmac STATIC_CHAIN +@defmacx STATIC_CHAIN_INCOMING +If the static chain is passed in memory, these macros provide rtx giving +@code{mem} expressions that denote where they are stored. +@code{STATIC_CHAIN} and @code{STATIC_CHAIN_INCOMING} give the locations +as seen by the calling and called functions, respectively. Often the former +will be at an offset from the stack pointer and the latter at an offset from +the frame pointer. + +@findex stack_pointer_rtx +@findex frame_pointer_rtx +@findex arg_pointer_rtx +The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and +@code{arg_pointer_rtx} will have been initialized prior to the use of these +macros and should be used to refer to those items. + +If the static chain is passed in a register, the two previous macros should +be defined instead. +@end defmac + +@defmac DWARF_FRAME_REGISTERS +This macro specifies the maximum number of hard registers that can be +saved in a call frame. This is used to size data structures used in +DWARF2 exception handling. + +Prior to GCC 3.0, this macro was needed in order to establish a stable +exception handling ABI in the face of adding new hard registers for ISA +extensions. In GCC 3.0 and later, the EH ABI is insulated from changes +in the number of hard registers. Nevertheless, this macro can still be +used to reduce the runtime memory requirements of the exception handling +routines, which can be substantial if the ISA contains a lot of +registers that are not call-saved. + +If this macro is not defined, it defaults to +@code{FIRST_PSEUDO_REGISTER}. +@end defmac + +@defmac PRE_GCC3_DWARF_FRAME_REGISTERS + +This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided +for backward compatibility in pre GCC 3.0 compiled code. + +If this macro is not defined, it defaults to +@code{DWARF_FRAME_REGISTERS}. +@end defmac + +@defmac DWARF_REG_TO_UNWIND_COLUMN (@var{regno}) + +Define this macro if the target's representation for dwarf registers +is different than the internal representation for unwind column. +Given a dwarf register, this macro should return the internal unwind +column number to use instead. + +See the PowerPC's SPE target for an example. +@end defmac + +@defmac DWARF_FRAME_REGNUM (@var{regno}) + +Define this macro if the target's representation for dwarf registers +used in .eh_frame or .debug_frame is different from that used in other +debug info sections. Given a GCC hard register number, this macro +should return the .eh_frame register number. The default is +@code{DBX_REGISTER_NUMBER (@var{regno})}. + +@end defmac + +@defmac DWARF2_FRAME_REG_OUT (@var{regno}, @var{for_eh}) + +Define this macro to map register numbers held in the call frame info +that GCC has collected using @code{DWARF_FRAME_REGNUM} to those that +should be output in .debug_frame (@code{@var{for_eh}} is zero) and +.eh_frame (@code{@var{for_eh}} is nonzero). The default is to +return @code{@var{regno}}. + +@end defmac + +@node Elimination +@subsection Eliminating Frame Pointer and Arg Pointer + +@c prevent bad page break with this line +This is about eliminating the frame pointer and arg pointer. + +@defmac FRAME_POINTER_REQUIRED +A C expression which is nonzero if a function must have and use a frame +pointer. This expression is evaluated in the reload pass. If its value is +nonzero the function will have a frame pointer. + +The expression can in principle examine the current function and decide +according to the facts, but on most machines the constant 0 or the +constant 1 suffices. Use 0 when the machine allows code to be generated +with no frame pointer, and doing so saves some time or space. Use 1 +when there is no possible advantage to avoiding a frame pointer. + +In certain cases, the compiler does not know how to produce valid code +without a frame pointer. The compiler recognizes those cases and +automatically gives the function a frame pointer regardless of what +@code{FRAME_POINTER_REQUIRED} says. You don't need to worry about +them. + +In a function that does not require a frame pointer, the frame pointer +register can be allocated for ordinary usage, unless you mark it as a +fixed register. See @code{FIXED_REGISTERS} for more information. +@end defmac + +@findex get_frame_size +@defmac INITIAL_FRAME_POINTER_OFFSET (@var{depth-var}) +A C statement to store in the variable @var{depth-var} the difference +between the frame pointer and the stack pointer values immediately after +the function prologue. The value would be computed from information +such as the result of @code{get_frame_size ()} and the tables of +registers @code{regs_ever_live} and @code{call_used_regs}. + +If @code{ELIMINABLE_REGS} is defined, this macro will be not be used and +need not be defined. Otherwise, it must be defined even if +@code{FRAME_POINTER_REQUIRED} is defined to always be true; in that +case, you may set @var{depth-var} to anything. +@end defmac + +@defmac ELIMINABLE_REGS +If defined, this macro specifies a table of register pairs used to +eliminate unneeded registers that point into the stack frame. If it is not +defined, the only elimination attempted by the compiler is to replace +references to the frame pointer with references to the stack pointer. + +The definition of this macro is a list of structure initializations, each +of which specifies an original and replacement register. + +On some machines, the position of the argument pointer is not known until +the compilation is completed. In such a case, a separate hard register +must be used for the argument pointer. This register can be eliminated by +replacing it with either the frame pointer or the argument pointer, +depending on whether or not the frame pointer has been eliminated. + +In this case, you might specify: +@smallexample +#define ELIMINABLE_REGS \ +@{@{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM@}, \ + @{ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM@}, \ + @{FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM@}@} +@end smallexample + +Note that the elimination of the argument pointer with the stack pointer is +specified first since that is the preferred elimination. +@end defmac + +@defmac CAN_ELIMINATE (@var{from-reg}, @var{to-reg}) +A C expression that returns nonzero if the compiler is allowed to try +to replace register number @var{from-reg} with register number +@var{to-reg}. This macro need only be defined if @code{ELIMINABLE_REGS} +is defined, and will usually be the constant 1, since most of the cases +preventing register elimination are things that the compiler already +knows about. +@end defmac + +@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var}) +This macro is similar to @code{INITIAL_FRAME_POINTER_OFFSET}. It +specifies the initial difference between the specified pair of +registers. This macro must be defined if @code{ELIMINABLE_REGS} is +defined. +@end defmac + +@node Stack Arguments +@subsection Passing Function Arguments on the Stack +@cindex arguments on stack +@cindex stack arguments + +The macros in this section control how arguments are passed +on the stack. See the following section for other macros that +control passing certain arguments in registers. + +@deftypefn {Target Hook} bool TARGET_PROMOTE_PROTOTYPES (tree @var{fntype}) +This target hook returns @code{true} if an argument declared in a +prototype as an integral type smaller than @code{int} should actually be +passed as an @code{int}. In addition to avoiding errors in certain +cases of mismatch, it also makes for better code on certain machines. +The default is to not promote prototypes. +@end deftypefn + +@defmac PUSH_ARGS +A C expression. If nonzero, push insns will be used to pass +outgoing arguments. +If the target machine does not have a push instruction, set it to zero. +That directs GCC to use an alternate strategy: to +allocate the entire argument block and then store the arguments into +it. When @code{PUSH_ARGS} is nonzero, @code{PUSH_ROUNDING} must be defined too. +@end defmac + +@defmac PUSH_ARGS_REVERSED +A C expression. If nonzero, function arguments will be evaluated from +last to first, rather than from first to last. If this macro is not +defined, it defaults to @code{PUSH_ARGS} on targets where the stack +and args grow in opposite directions, and 0 otherwise. +@end defmac + +@defmac PUSH_ROUNDING (@var{npushed}) +A C expression that is the number of bytes actually pushed onto the +stack when an instruction attempts to push @var{npushed} bytes. + +On some machines, the definition + +@smallexample +#define PUSH_ROUNDING(BYTES) (BYTES) +@end smallexample + +@noindent +will suffice. But on other machines, instructions that appear +to push one byte actually push two bytes in an attempt to maintain +alignment. Then the definition should be + +@smallexample +#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1) +@end smallexample +@end defmac + +@findex current_function_outgoing_args_size +@defmac ACCUMULATE_OUTGOING_ARGS +A C expression. If nonzero, the maximum amount of space required for outgoing arguments +will be computed and placed into the variable +@code{current_function_outgoing_args_size}. No space will be pushed +onto the stack for each call; instead, the function prologue should +increase the stack frame size by this amount. + +Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS} +is not proper. +@end defmac + +@defmac REG_PARM_STACK_SPACE (@var{fndecl}) +Define this macro if functions should assume that stack space has been +allocated for arguments even when their values are passed in +registers. + +The value of this macro is the size, in bytes, of the area reserved for +arguments passed in registers for the function represented by @var{fndecl}, +which can be zero if GCC is calling a library function. + +This space can be allocated by the caller, or be a part of the +machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says +which. +@end defmac +@c above is overfull. not sure what to do. --mew 5feb93 did +@c something, not sure if it looks good. --mew 10feb93 + +@defmac OUTGOING_REG_PARM_STACK_SPACE +Define this if it is the responsibility of the caller to allocate the area +reserved for arguments passed in registers. + +If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls +whether the space for these arguments counts in the value of +@code{current_function_outgoing_args_size}. +@end defmac + +@defmac STACK_PARMS_IN_REG_PARM_AREA +Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the +stack parameters don't skip the area specified by it. +@c i changed this, makes more sens and it should have taken care of the +@c overfull.. not as specific, tho. --mew 5feb93 + +Normally, when a parameter is not passed in registers, it is placed on the +stack beyond the @code{REG_PARM_STACK_SPACE} area. Defining this macro +suppresses this behavior and causes the parameter to be passed on the +stack in its natural location. +@end defmac + +@defmac RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size}) +A C expression that should indicate the number of bytes of its own +arguments that a function pops on returning, or 0 if the +function pops no arguments and the caller must therefore pop them all +after the function returns. + +@var{fundecl} is a C variable whose value is a tree node that describes +the function in question. Normally it is a node of type +@code{FUNCTION_DECL} that describes the declaration of the function. +From this you can obtain the @code{DECL_ATTRIBUTES} of the function. + +@var{funtype} is a C variable whose value is a tree node that +describes the function in question. Normally it is a node of type +@code{FUNCTION_TYPE} that describes the data type of the function. +From this it is possible to obtain the data types of the value and +arguments (if known). + +When a call to a library function is being considered, @var{fundecl} +will contain an identifier node for the library function. Thus, if +you need to distinguish among various library functions, you can do so +by their names. Note that ``library function'' in this context means +a function used to perform arithmetic, whose name is known specially +in the compiler and was not mentioned in the C code being compiled. + +@var{stack-size} is the number of bytes of arguments passed on the +stack. If a variable number of bytes is passed, it is zero, and +argument popping will always be the responsibility of the calling function. + +On the VAX, all functions always pop their arguments, so the definition +of this macro is @var{stack-size}. On the 68000, using the standard +calling convention, no functions pop their arguments, so the value of +the macro is always 0 in this case. But an alternative calling +convention is available in which functions that take a fixed number of +arguments pop them but other functions (such as @code{printf}) pop +nothing (the caller pops all). When this convention is in use, +@var{funtype} is examined to determine whether a function takes a fixed +number of arguments. +@end defmac + +@defmac CALL_POPS_ARGS (@var{cum}) +A C expression that should indicate the number of bytes a call sequence +pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS} +when compiling a function call. + +@var{cum} is the variable in which all arguments to the called function +have been accumulated. + +On certain architectures, such as the SH5, a call trampoline is used +that pops certain registers off the stack, depending on the arguments +that have been passed to the function. Since this is a property of the +call site, not of the called function, @code{RETURN_POPS_ARGS} is not +appropriate. +@end defmac + +@node Register Arguments +@subsection Passing Arguments in Registers +@cindex arguments in registers +@cindex registers arguments + +This section describes the macros which let you control how various +types of arguments are passed in registers or how they are arranged in +the stack. + +@defmac FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named}) +A C expression that controls whether a function argument is passed +in a register, and which register. + +The arguments are @var{cum}, which summarizes all the previous +arguments; @var{mode}, the machine mode of the argument; @var{type}, +the data type of the argument as a tree node or 0 if that is not known +(which happens for C support library functions); and @var{named}, +which is 1 for an ordinary argument and 0 for nameless arguments that +correspond to @samp{@dots{}} in the called function's prototype. +@var{type} can be an incomplete type if a syntax error has previously +occurred. + +The value of the expression is usually either a @code{reg} RTX for the +hard register in which to pass the argument, or zero to pass the +argument on the stack. + +For machines like the VAX and 68000, where normally all arguments are +pushed, zero suffices as a definition. + +The value of the expression can also be a @code{parallel} RTX@. This is +used when an argument is passed in multiple locations. The mode of the +@code{parallel} should be the mode of the entire argument. The +@code{parallel} holds any number of @code{expr_list} pairs; each one +describes where part of the argument is passed. In each +@code{expr_list} the first operand must be a @code{reg} RTX for the hard +register in which to pass this part of the argument, and the mode of the +register RTX indicates how large this part of the argument is. The +second operand of the @code{expr_list} is a @code{const_int} which gives +the offset in bytes into the entire argument of where this part starts. +As a special exception the first @code{expr_list} in the @code{parallel} +RTX may have a first operand of zero. This indicates that the entire +argument is also stored on the stack. + +The last time this macro is called, it is called with @code{MODE == +VOIDmode}, and its result is passed to the @code{call} or @code{call_value} +pattern as operands 2 and 3 respectively. + +@cindex @file{stdarg.h} and register arguments +The usual way to make the ISO library @file{stdarg.h} work on a machine +where some arguments are usually passed in registers, is to cause +nameless arguments to be passed on the stack instead. This is done +by making @code{FUNCTION_ARG} return 0 whenever @var{named} is 0. + +@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{FUNCTION_ARG} +@cindex @code{REG_PARM_STACK_SPACE}, and @code{FUNCTION_ARG} +You may use the hook @code{targetm.calls.must_pass_in_stack} +in the definition of this macro to determine if this argument is of a +type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE} +is not defined and @code{FUNCTION_ARG} returns nonzero for such an +argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is +defined, the argument will be computed in the stack and then loaded into +a register. +@end defmac + +@deftypefn {Target Hook} bool TARGET_MUST_PASS_IN_STACK (enum machine_mode @var{mode}, tree @var{type}) +This target hook should return @code{true} if we should not pass @var{type} +solely in registers. The file @file{expr.h} defines a +definition that is usually appropriate, refer to @file{expr.h} for additional +documentation. +@end deftypefn + +@defmac FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named}) +Define this macro if the target machine has ``register windows'', so +that the register in which a function sees an arguments is not +necessarily the same as the one in which the caller passed the +argument. + +For such machines, @code{FUNCTION_ARG} computes the register in which +the caller passes the value, and @code{FUNCTION_INCOMING_ARG} should +be defined in a similar fashion to tell the function being called +where the arguments will arrive. + +If @code{FUNCTION_INCOMING_ARG} is not defined, @code{FUNCTION_ARG} +serves both purposes. +@end defmac + +@deftypefn {Target Hook} int TARGET_ARG_PARTIAL_BYTES (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named}) +This target hook returns the number of bytes at the beginning of an +argument that must be put in registers. The value must be zero for +arguments that are passed entirely in registers or that are entirely +pushed on the stack. + +On some machines, certain arguments must be passed partially in +registers and partially in memory. On these machines, typically the +first few words of arguments are passed in registers, and the rest +on the stack. If a multi-word argument (a @code{double} or a +structure) crosses that boundary, its first few words must be passed +in registers and the rest must be pushed. This macro tells the +compiler when this occurs, and how many bytes should go in registers. + +@code{FUNCTION_ARG} for these arguments should return the first +register to be used by the caller for this argument; likewise +@code{FUNCTION_INCOMING_ARG}, for the called function. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_PASS_BY_REFERENCE (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named}) +This target hook should return @code{true} if an argument at the +position indicated by @var{cum} should be passed by reference. This +predicate is queried after target independent reasons for being +passed by reference, such as @code{TREE_ADDRESSABLE (type)}. + +If the hook returns true, a copy of that argument is made in memory and a +pointer to the argument is passed instead of the argument itself. +The pointer is passed in whatever way is appropriate for passing a pointer +to that type. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CALLEE_COPIES (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named}) +The function argument described by the parameters to this hook is +known to be passed by reference. The hook should return true if the +function argument should be copied by the callee instead of copied +by the caller. + +For any argument for which the hook returns true, if it can be +determined that the argument is not modified, then a copy need +not be generated. + +The default version of this hook always returns false. +@end deftypefn + +@defmac CUMULATIVE_ARGS +A C type for declaring a variable that is used as the first argument of +@code{FUNCTION_ARG} and other related values. For some target machines, +the type @code{int} suffices and can hold the number of bytes of +argument so far. + +There is no need to record in @code{CUMULATIVE_ARGS} anything about the +arguments that have been passed on the stack. The compiler has other +variables to keep track of that. For target machines on which all +arguments are passed on the stack, there is no need to store anything in +@code{CUMULATIVE_ARGS}; however, the data structure must exist and +should not be empty, so use @code{int}. +@end defmac + +@defmac INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{fndecl}, @var{n_named_args}) +A C statement (sans semicolon) for initializing the variable +@var{cum} for the state at the beginning of the argument list. The +variable has type @code{CUMULATIVE_ARGS}. The value of @var{fntype} +is the tree node for the data type of the function which will receive +the args, or 0 if the args are to a compiler support library function. +For direct calls that are not libcalls, @var{fndecl} contain the +declaration node of the function. @var{fndecl} is also set when +@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function +being compiled. @var{n_named_args} is set to the number of named +arguments, including a structure return address if it is passed as a +parameter, when making a call. When processing incoming arguments, +@var{n_named_args} is set to @minus{}1. + +When processing a call to a compiler support library function, +@var{libname} identifies which one. It is a @code{symbol_ref} rtx which +contains the name of the function, as a string. @var{libname} is 0 when +an ordinary C function call is being processed. Thus, each time this +macro is called, either @var{libname} or @var{fntype} is nonzero, but +never both of them at once. +@end defmac + +@defmac INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname}) +Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls, +it gets a @code{MODE} argument instead of @var{fntype}, that would be +@code{NULL}. @var{indirect} would always be zero, too. If this macro +is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname, +0)} is used instead. +@end defmac + +@defmac INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname}) +Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of +finding the arguments for the function being compiled. If this macro is +undefined, @code{INIT_CUMULATIVE_ARGS} is used instead. + +The value passed for @var{libname} is always 0, since library routines +with special calling conventions are never compiled with GCC@. The +argument @var{libname} exists for symmetry with +@code{INIT_CUMULATIVE_ARGS}. +@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe. +@c --mew 5feb93 i switched the order of the sentences. --mew 10feb93 +@end defmac + +@defmac FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named}) +A C statement (sans semicolon) to update the summarizer variable +@var{cum} to advance past an argument in the argument list. The +values @var{mode}, @var{type} and @var{named} describe that argument. +Once this is done, the variable @var{cum} is suitable for analyzing +the @emph{following} argument with @code{FUNCTION_ARG}, etc. + +This macro need not do anything if the argument in question was passed +on the stack. The compiler knows how to track the amount of stack space +used for arguments without any special help. +@end defmac + +@defmac FUNCTION_ARG_PADDING (@var{mode}, @var{type}) +If defined, a C expression which determines whether, and in which direction, +to pad out an argument with extra space. The value should be of type +@code{enum direction}: either @code{upward} to pad above the argument, +@code{downward} to pad below, or @code{none} to inhibit padding. + +The @emph{amount} of padding is always just enough to reach the next +multiple of @code{FUNCTION_ARG_BOUNDARY}; this macro does not control +it. + +This macro has a default definition which is right for most systems. +For little-endian machines, the default is to pad upward. For +big-endian machines, the default is to pad downward for an argument of +constant size shorter than an @code{int}, and upward otherwise. +@end defmac + +@defmac PAD_VARARGS_DOWN +If defined, a C expression which determines whether the default +implementation of va_arg will attempt to pad down before reading the +next argument, if that argument is smaller than its aligned space as +controlled by @code{PARM_BOUNDARY}. If this macro is not defined, all such +arguments are padded down if @code{BYTES_BIG_ENDIAN} is true. +@end defmac + +@defmac BLOCK_REG_PADDING (@var{mode}, @var{type}, @var{first}) +Specify padding for the last element of a block move between registers and +memory. @var{first} is nonzero if this is the only element. Defining this +macro allows better control of register function parameters on big-endian +machines, without using @code{PARALLEL} rtl. In particular, +@code{MUST_PASS_IN_STACK} need not test padding and mode of types in +registers, as there is no longer a "wrong" part of a register; For example, +a three byte aggregate may be passed in the high part of a register if so +required. +@end defmac + +@defmac FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type}) +If defined, a C expression that gives the alignment boundary, in bits, +of an argument with the specified mode and type. If it is not defined, +@code{PARM_BOUNDARY} is used for all arguments. +@end defmac + +@defmac FUNCTION_ARG_REGNO_P (@var{regno}) +A C expression that is nonzero if @var{regno} is the number of a hard +register in which function arguments are sometimes passed. This does +@emph{not} include implicit arguments such as the static chain and +the structure-value address. On many machines, no registers can be +used for this purpose since all function arguments are pushed on the +stack. +@end defmac + +@deftypefn {Target Hook} bool TARGET_SPLIT_COMPLEX_ARG (tree @var{type}) +This hook should return true if parameter of type @var{type} are passed +as two scalar parameters. By default, GCC will attempt to pack complex +arguments into the target's word size. Some ABIs require complex arguments +to be split and treated as their individual components. For example, on +AIX64, complex floats should be passed in a pair of floating point +registers, even though a complex float would fit in one 64-bit floating +point register. + +The default value of this hook is @code{NULL}, which is treated as always +false. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_BUILD_BUILTIN_VA_LIST (void) +This hook returns a type node for @code{va_list} for the target. +The default version of the hook returns @code{void*}. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_GIMPLIFY_VA_ARG_EXPR (tree @var{valist}, tree @var{type}, tree *@var{pre_p}, tree *@var{post_p}) +This hook performs target-specific gimplification of +@code{VA_ARG_EXPR}. The first two parameters correspond to the +arguments to @code{va_arg}; the latter two are as in +@code{gimplify.c:gimplify_expr}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_VALID_POINTER_MODE (enum machine_mode @var{mode}) +Define this to return nonzero if the port can handle pointers +with machine mode @var{mode}. The default version of this +hook returns true for both @code{ptr_mode} and @code{Pmode}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_SCALAR_MODE_SUPPORTED_P (enum machine_mode @var{mode}) +Define this to return nonzero if the port is prepared to handle +insns involving scalar mode @var{mode}. For a scalar mode to be +considered supported, all the basic arithmetic and comparisons +must work. + +The default version of this hook returns true for any mode +required to handle the basic C types (as defined by the port). +Included here are the double-word arithmetic supported by the +code in @file{optabs.c}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_VECTOR_MODE_SUPPORTED_P (enum machine_mode @var{mode}) +Define this to return nonzero if the port is prepared to handle +insns involving vector mode @var{mode}. At the very least, it +must have move patterns for this mode. +@end deftypefn + +@node Scalar Return +@subsection How Scalar Function Values Are Returned +@cindex return values in registers +@cindex values, returned by functions +@cindex scalars, returned as values + +This section discusses the macros that control returning scalars as +values---values that can fit in registers. + +@deftypefn {Target Hook} rtx TARGET_FUNCTION_VALUE (tree @var{ret_type}, tree @var{fn_decl_or_type}, bool @var{outgoing}) + +Define this to return an RTX representing the place where a function +returns or receives a value of data type @var{ret_type}, a tree node +node representing a data type. @var{fn_decl_or_type} is a tree node +representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a +function being called. If @var{outgoing} is false, the hook should +compute the register in which the caller will see the return value. +Otherwise, the hook should return an RTX representing the place where +a function returns a value. + +On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant. +(Actually, on most machines, scalar values are returned in the same +place regardless of mode.) The value of the expression is usually a +@code{reg} RTX for the hard register where the return value is stored. +The value can also be a @code{parallel} RTX, if the return value is in +multiple places. See @code{FUNCTION_ARG} for an explanation of the +@code{parallel} form. + +If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply +the same promotion rules specified in @code{PROMOTE_MODE} if +@var{valtype} is a scalar type. + +If the precise function being called is known, @var{func} is a tree +node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null +pointer. This makes it possible to use a different value-returning +convention for specific functions when all their calls are +known. + +Some target machines have ``register windows'' so that the register in +which a function returns its value is not the same as the one in which +the caller sees the value. For such machines, you should return +different RTX depending on @var{outgoing}. + +@code{TARGET_FUNCTION_VALUE} is not used for return values with +aggregate data types, because these are returned in another way. See +@code{TARGET_STRUCT_VALUE_RTX} and related macros, below. +@end deftypefn + +@defmac FUNCTION_VALUE (@var{valtype}, @var{func}) +This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for +a new target instead. +@end defmac + +@defmac FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func}) +This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for +a new target instead. +@end defmac + +@defmac LIBCALL_VALUE (@var{mode}) +A C expression to create an RTX representing the place where a library +function returns a value of mode @var{mode}. If the precise function +being called is known, @var{func} is a tree node +(@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null +pointer. This makes it possible to use a different value-returning +convention for specific functions when all their calls are +known. + +Note that ``library function'' in this context means a compiler +support routine, used to perform arithmetic, whose name is known +specially by the compiler and was not mentioned in the C code being +compiled. + +The definition of @code{LIBRARY_VALUE} need not be concerned aggregate +data types, because none of the library functions returns such types. +@end defmac + +@defmac FUNCTION_VALUE_REGNO_P (@var{regno}) +A C expression that is nonzero if @var{regno} is the number of a hard +register in which the values of called function may come back. + +A register whose use for returning values is limited to serving as the +second of a pair (for a value of type @code{double}, say) need not be +recognized by this macro. So for most machines, this definition +suffices: + +@smallexample +#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0) +@end smallexample + +If the machine has register windows, so that the caller and the called +function use different registers for the return value, this macro +should recognize only the caller's register numbers. +@end defmac + +@defmac APPLY_RESULT_SIZE +Define this macro if @samp{untyped_call} and @samp{untyped_return} +need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for +saving and restoring an arbitrary return value. +@end defmac + +@deftypefn {Target Hook} bool TARGET_RETURN_IN_MSB (tree @var{type}) +This hook should return true if values of type @var{type} are returned +at the most significant end of a register (in other words, if they are +padded at the least significant end). You can assume that @var{type} +is returned in a register; the caller is required to check this. + +Note that the register provided by @code{TARGET_FUNCTION_VALUE} must +be able to hold the complete return value. For example, if a 1-, 2- +or 3-byte structure is returned at the most significant end of a +4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an +@code{SImode} rtx. +@end deftypefn + +@node Aggregate Return +@subsection How Large Values Are Returned +@cindex aggregates as return values +@cindex large return values +@cindex returning aggregate values +@cindex structure value address + +When a function value's mode is @code{BLKmode} (and in some other +cases), the value is not returned according to +@code{TARGET_FUNCTION_VALUE} (@pxref{Scalar Return}). Instead, the +caller passes the address of a block of memory in which the value +should be stored. This address is called the @dfn{structure value +address}. + +This section describes how to control returning structure values in +memory. + +@deftypefn {Target Hook} bool TARGET_RETURN_IN_MEMORY (tree @var{type}, tree @var{fntype}) +This target hook should return a nonzero value to say to return the +function value in memory, just as large structures are always returned. +Here @var{type} will be the data type of the value, and @var{fntype} +will be the type of the function doing the returning, or @code{NULL} for +libcalls. + +Note that values of mode @code{BLKmode} must be explicitly handled +by this function. Also, the option @option{-fpcc-struct-return} +takes effect regardless of this macro. On most systems, it is +possible to leave the hook undefined; this causes a default +definition to be used, whose value is the constant 1 for @code{BLKmode} +values, and 0 otherwise. + +Do not use this hook to indicate that structures and unions should always +be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN} +to indicate this. +@end deftypefn + +@defmac DEFAULT_PCC_STRUCT_RETURN +Define this macro to be 1 if all structure and union return values must be +in memory. Since this results in slower code, this should be defined +only if needed for compatibility with other compilers or with an ABI@. +If you define this macro to be 0, then the conventions used for structure +and union return values are decided by the @code{TARGET_RETURN_IN_MEMORY} +target hook. + +If not defined, this defaults to the value 1. +@end defmac + +@deftypefn {Target Hook} rtx TARGET_STRUCT_VALUE_RTX (tree @var{fndecl}, int @var{incoming}) +This target hook should return the location of the structure value +address (normally a @code{mem} or @code{reg}), or 0 if the address is +passed as an ``invisible'' first argument. Note that @var{fndecl} may +be @code{NULL}, for libcalls. You do not need to define this target +hook if the address is always passed as an ``invisible'' first +argument. + +On some architectures the place where the structure value address +is found by the called function is not the same place that the +caller put it. This can be due to register windows, or it could +be because the function prologue moves it to a different place. +@var{incoming} is @code{1} or @code{2} when the location is needed in +the context of the called function, and @code{0} in the context of +the caller. + +If @var{incoming} is nonzero and the address is to be found on the +stack, return a @code{mem} which refers to the frame pointer. If +@var{incoming} is @code{2}, the result is being used to fetch the +structure value address at the beginning of a function. If you need +to emit adjusting code, you should do it at this point. +@end deftypefn + +@defmac PCC_STATIC_STRUCT_RETURN +Define this macro if the usual system convention on the target machine +for returning structures and unions is for the called function to return +the address of a static variable containing the value. + +Do not define this if the usual system convention is for the caller to +pass an address to the subroutine. + +This macro has effect in @option{-fpcc-struct-return} mode, but it does +nothing when you use @option{-freg-struct-return} mode. +@end defmac + +@node Caller Saves +@subsection Caller-Saves Register Allocation + +If you enable it, GCC can save registers around function calls. This +makes it possible to use call-clobbered registers to hold variables that +must live across calls. + +@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls}) +A C expression to determine whether it is worthwhile to consider placing +a pseudo-register in a call-clobbered hard register and saving and +restoring it around each function call. The expression should be 1 when +this is worth doing, and 0 otherwise. + +If you don't define this macro, a default is used which is good on most +machines: @code{4 * @var{calls} < @var{refs}}. +@end defmac + +@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs}) +A C expression specifying which mode is required for saving @var{nregs} +of a pseudo-register in call-clobbered hard register @var{regno}. If +@var{regno} is unsuitable for caller save, @code{VOIDmode} should be +returned. For most machines this macro need not be defined since GCC +will select the smallest suitable mode. +@end defmac + +@node Function Entry +@subsection Function Entry and Exit +@cindex function entry and exit +@cindex prologue +@cindex epilogue + +This section describes the macros that output function entry +(@dfn{prologue}) and exit (@dfn{epilogue}) code. + +@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_PROLOGUE (FILE *@var{file}, HOST_WIDE_INT @var{size}) +If defined, a function that outputs the assembler code for entry to a +function. The prologue is responsible for setting up the stack frame, +initializing the frame pointer register, saving registers that must be +saved, and allocating @var{size} additional bytes of storage for the +local variables. @var{size} is an integer. @var{file} is a stdio +stream to which the assembler code should be output. + +The label for the beginning of the function need not be output by this +macro. That has already been done when the macro is run. + +@findex regs_ever_live +To determine which registers to save, the macro can refer to the array +@code{regs_ever_live}: element @var{r} is nonzero if hard register +@var{r} is used anywhere within the function. This implies the function +prologue should save register @var{r}, provided it is not one of the +call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use +@code{regs_ever_live}.) + +On machines that have ``register windows'', the function entry code does +not save on the stack the registers that are in the windows, even if +they are supposed to be preserved by function calls; instead it takes +appropriate steps to ``push'' the register stack, if any non-call-used +registers are used in the function. + +@findex frame_pointer_needed +On machines where functions may or may not have frame-pointers, the +function entry code must vary accordingly; it must set up the frame +pointer if one is wanted, and not otherwise. To determine whether a +frame pointer is in wanted, the macro can refer to the variable +@code{frame_pointer_needed}. The variable's value will be 1 at run +time in a function that needs a frame pointer. @xref{Elimination}. + +The function entry code is responsible for allocating any stack space +required for the function. This stack space consists of the regions +listed below. In most cases, these regions are allocated in the +order listed, with the last listed region closest to the top of the +stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and +the highest address if it is not defined). You can use a different order +for a machine if doing so is more convenient or required for +compatibility reasons. Except in cases where required by standard +or by a debugger, there is no reason why the stack layout used by GCC +need agree with that used by other compilers for a machine. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_END_PROLOGUE (FILE *@var{file}) +If defined, a function that outputs assembler code at the end of a +prologue. This should be used when the function prologue is being +emitted as RTL, and you have some extra assembler that needs to be +emitted. @xref{prologue instruction pattern}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_BEGIN_EPILOGUE (FILE *@var{file}) +If defined, a function that outputs assembler code at the start of an +epilogue. This should be used when the function epilogue is being +emitted as RTL, and you have some extra assembler that needs to be +emitted. @xref{epilogue instruction pattern}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_EPILOGUE (FILE *@var{file}, HOST_WIDE_INT @var{size}) +If defined, a function that outputs the assembler code for exit from a +function. The epilogue is responsible for restoring the saved +registers and stack pointer to their values when the function was +called, and returning control to the caller. This macro takes the +same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the +registers to restore are determined from @code{regs_ever_live} and +@code{CALL_USED_REGISTERS} in the same way. + +On some machines, there is a single instruction that does all the work +of returning from the function. On these machines, give that +instruction the name @samp{return} and do not define the macro +@code{TARGET_ASM_FUNCTION_EPILOGUE} at all. + +Do not define a pattern named @samp{return} if you want the +@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target +switches to control whether return instructions or epilogues are used, +define a @samp{return} pattern with a validity condition that tests the +target switches appropriately. If the @samp{return} pattern's validity +condition is false, epilogues will be used. + +On machines where functions may or may not have frame-pointers, the +function exit code must vary accordingly. Sometimes the code for these +two cases is completely different. To determine whether a frame pointer +is wanted, the macro can refer to the variable +@code{frame_pointer_needed}. The variable's value will be 1 when compiling +a function that needs a frame pointer. + +Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and +@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially. +The C variable @code{current_function_is_leaf} is nonzero for such a +function. @xref{Leaf Functions}. + +On some machines, some functions pop their arguments on exit while +others leave that for the caller to do. For example, the 68020 when +given @option{-mrtd} pops arguments in functions that take a fixed +number of arguments. + +@findex current_function_pops_args +Your definition of the macro @code{RETURN_POPS_ARGS} decides which +functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE} +needs to know what was decided. The variable that is called +@code{current_function_pops_args} is the number of bytes of its +arguments that a function should pop. @xref{Scalar Return}. +@c what is the "its arguments" in the above sentence referring to, pray +@c tell? --mew 5feb93 +@end deftypefn + +@itemize @bullet +@item +@findex current_function_pretend_args_size +A region of @code{current_function_pretend_args_size} bytes of +uninitialized space just underneath the first argument arriving on the +stack. (This may not be at the very start of the allocated stack region +if the calling sequence has pushed anything else since pushing the stack +arguments. But usually, on such machines, nothing else has been pushed +yet, because the function prologue itself does all the pushing.) This +region is used on machines where an argument may be passed partly in +registers and partly in memory, and, in some cases to support the +features in @code{<stdarg.h>}. + +@item +An area of memory used to save certain registers used by the function. +The size of this area, which may also include space for such things as +the return address and pointers to previous stack frames, is +machine-specific and usually depends on which registers have been used +in the function. Machines with register windows often do not require +a save area. + +@item +A region of at least @var{size} bytes, possibly rounded up to an allocation +boundary, to contain the local variables of the function. On some machines, +this region and the save area may occur in the opposite order, with the +save area closer to the top of the stack. + +@item +@cindex @code{ACCUMULATE_OUTGOING_ARGS} and stack frames +Optionally, when @code{ACCUMULATE_OUTGOING_ARGS} is defined, a region of +@code{current_function_outgoing_args_size} bytes to be used for outgoing +argument lists of the function. @xref{Stack Arguments}. +@end itemize + +@defmac EXIT_IGNORE_STACK +Define this macro as a C expression that is nonzero if the return +instruction or the function epilogue ignores the value of the stack +pointer; in other words, if it is safe to delete an instruction to +adjust the stack pointer before a return from the function. The +default is 0. + +Note that this macro's value is relevant only for functions for which +frame pointers are maintained. It is never safe to delete a final +stack adjustment in a function that has no frame pointer, and the +compiler knows this regardless of @code{EXIT_IGNORE_STACK}. +@end defmac + +@defmac EPILOGUE_USES (@var{regno}) +Define this macro as a C expression that is nonzero for registers that are +used by the epilogue or the @samp{return} pattern. The stack and frame +pointer registers are already assumed to be used as needed. +@end defmac + +@defmac EH_USES (@var{regno}) +Define this macro as a C expression that is nonzero for registers that are +used by the exception handling mechanism, and so should be considered live +on entry to an exception edge. +@end defmac + +@defmac DELAY_SLOTS_FOR_EPILOGUE +Define this macro if the function epilogue contains delay slots to which +instructions from the rest of the function can be ``moved''. The +definition should be a C expression whose value is an integer +representing the number of delay slots there. +@end defmac + +@defmac ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n}) +A C expression that returns 1 if @var{insn} can be placed in delay +slot number @var{n} of the epilogue. + +The argument @var{n} is an integer which identifies the delay slot now +being considered (since different slots may have different rules of +eligibility). It is never negative and is always less than the number +of epilogue delay slots (what @code{DELAY_SLOTS_FOR_EPILOGUE} returns). +If you reject a particular insn for a given delay slot, in principle, it +may be reconsidered for a subsequent delay slot. Also, other insns may +(at least in principle) be considered for the so far unfilled delay +slot. + +@findex current_function_epilogue_delay_list +@findex final_scan_insn +The insns accepted to fill the epilogue delay slots are put in an RTL +list made with @code{insn_list} objects, stored in the variable +@code{current_function_epilogue_delay_list}. The insn for the first +delay slot comes first in the list. Your definition of the macro +@code{TARGET_ASM_FUNCTION_EPILOGUE} should fill the delay slots by +outputting the insns in this list, usually by calling +@code{final_scan_insn}. + +You need not define this macro if you did not define +@code{DELAY_SLOTS_FOR_EPILOGUE}. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_MI_THUNK (FILE *@var{file}, tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, HOST_WIDE_INT @var{vcall_offset}, tree @var{function}) +A function that outputs the assembler code for a thunk +function, used to implement C++ virtual function calls with multiple +inheritance. The thunk acts as a wrapper around a virtual function, +adjusting the implicit object parameter before handing control off to +the real function. + +First, emit code to add the integer @var{delta} to the location that +contains the incoming first argument. Assume that this argument +contains a pointer, and is the one used to pass the @code{this} pointer +in C++. This is the incoming argument @emph{before} the function prologue, +e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of +all other incoming arguments. + +Then, if @var{vcall_offset} is nonzero, an additional adjustment should be +made after adding @code{delta}. In particular, if @var{p} is the +adjusted pointer, the following adjustment should be made: + +@smallexample +p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)] +@end smallexample + +After the additions, emit code to jump to @var{function}, which is a +@code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does +not touch the return address. Hence returning from @var{FUNCTION} will +return to whoever called the current @samp{thunk}. + +The effect must be as if @var{function} had been called directly with +the adjusted first argument. This macro is responsible for emitting all +of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE} +and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked. + +The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function} +have already been extracted from it.) It might possibly be useful on +some targets, but probably not. + +If you do not define this macro, the target-independent code in the C++ +front end will generate a less efficient heavyweight thunk that calls +@var{function} instead of jumping to it. The generic approach does +not support varargs. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_ASM_CAN_OUTPUT_MI_THUNK (tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, HOST_WIDE_INT @var{vcall_offset}, tree @var{function}) +A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able +to output the assembler code for the thunk function specified by the +arguments it is passed, and false otherwise. In the latter case, the +generic approach will be used by the C++ front end, with the limitations +previously exposed. +@end deftypefn + +@node Profiling +@subsection Generating Code for Profiling +@cindex profiling, code generation + +These macros will help you generate code for profiling. + +@defmac FUNCTION_PROFILER (@var{file}, @var{labelno}) +A C statement or compound statement to output to @var{file} some +assembler code to call the profiling subroutine @code{mcount}. + +@findex mcount +The details of how @code{mcount} expects to be called are determined by +your operating system environment, not by GCC@. To figure them out, +compile a small program for profiling using the system's installed C +compiler and look at the assembler code that results. + +Older implementations of @code{mcount} expect the address of a counter +variable to be loaded into some register. The name of this variable is +@samp{LP} followed by the number @var{labelno}, so you would generate +the name using @samp{LP%d} in a @code{fprintf}. +@end defmac + +@defmac PROFILE_HOOK +A C statement or compound statement to output to @var{file} some assembly +code to call the profiling subroutine @code{mcount} even the target does +not support profiling. +@end defmac + +@defmac NO_PROFILE_COUNTERS +Define this macro to be an expression with a nonzero value if the +@code{mcount} subroutine on your system does not need a counter variable +allocated for each function. This is true for almost all modern +implementations. If you define this macro, you must not use the +@var{labelno} argument to @code{FUNCTION_PROFILER}. +@end defmac + +@defmac PROFILE_BEFORE_PROLOGUE +Define this macro if the code for function profiling should come before +the function prologue. Normally, the profiling code comes after. +@end defmac + +@node Tail Calls +@subsection Permitting tail calls +@cindex tail calls + +@deftypefn {Target Hook} bool TARGET_FUNCTION_OK_FOR_SIBCALL (tree @var{decl}, tree @var{exp}) +True if it is ok to do sibling call optimization for the specified +call expression @var{exp}. @var{decl} will be the called function, +or @code{NULL} if this is an indirect call. + +It is not uncommon for limitations of calling conventions to prevent +tail calls to functions outside the current unit of translation, or +during PIC compilation. The hook is used to enforce these restrictions, +as the @code{sibcall} md pattern can not fail, or fall over to a +``normal'' call. The criteria for successful sibling call optimization +may vary greatly between different architectures. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap *@var{regs}) +Add any hard registers to @var{regs} that are live on entry to the +function. This hook only needs to be defined to provide registers that +cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved +registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM, +TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES, +FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM. +@end deftypefn + +@node Stack Smashing Protection +@subsection Stack smashing protection +@cindex stack smashing protection + +@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_GUARD (void) +This hook returns a @code{DECL} node for the external variable to use +for the stack protection guard. This variable is initialized by the +runtime to some random value and is used to initialize the guard value +that is placed at the top of the local stack frame. The type of this +variable must be @code{ptr_type_node}. + +The default version of this hook creates a variable called +@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_FAIL (void) +This hook returns a tree expression that alerts the runtime that the +stack protect guard variable has been modified. This expression should +involve a call to a @code{noreturn} function. + +The default version of this hook invokes a function called +@samp{__stack_chk_fail}, taking no arguments. This function is +normally defined in @file{libgcc2.c}. +@end deftypefn + +@node Varargs +@section Implementing the Varargs Macros +@cindex varargs implementation + +GCC comes with an implementation of @code{<varargs.h>} and +@code{<stdarg.h>} that work without change on machines that pass arguments +on the stack. Other machines require their own implementations of +varargs, and the two machine independent header files must have +conditionals to include it. + +ISO @code{<stdarg.h>} differs from traditional @code{<varargs.h>} mainly in +the calling convention for @code{va_start}. The traditional +implementation takes just one argument, which is the variable in which +to store the argument pointer. The ISO implementation of +@code{va_start} takes an additional second argument. The user is +supposed to write the last named argument of the function here. + +However, @code{va_start} should not use this argument. The way to find +the end of the named arguments is with the built-in functions described +below. + +@defmac __builtin_saveregs () +Use this built-in function to save the argument registers in memory so +that the varargs mechanism can access them. Both ISO and traditional +versions of @code{va_start} must use @code{__builtin_saveregs}, unless +you use @code{TARGET_SETUP_INCOMING_VARARGS} (see below) instead. + +On some machines, @code{__builtin_saveregs} is open-coded under the +control of the target hook @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. On +other machines, it calls a routine written in assembler language, +found in @file{libgcc2.c}. + +Code generated for the call to @code{__builtin_saveregs} appears at the +beginning of the function, as opposed to where the call to +@code{__builtin_saveregs} is written, regardless of what the code is. +This is because the registers must be saved before the function starts +to use them for its own purposes. +@c i rewrote the first sentence above to fix an overfull hbox. --mew +@c 10feb93 +@end defmac + +@defmac __builtin_args_info (@var{category}) +Use this built-in function to find the first anonymous arguments in +registers. + +In general, a machine may have several categories of registers used for +arguments, each for a particular category of data types. (For example, +on some machines, floating-point registers are used for floating-point +arguments while other arguments are passed in the general registers.) +To make non-varargs functions use the proper calling convention, you +have defined the @code{CUMULATIVE_ARGS} data type to record how many +registers in each category have been used so far + +@code{__builtin_args_info} accesses the same data structure of type +@code{CUMULATIVE_ARGS} after the ordinary argument layout is finished +with it, with @var{category} specifying which word to access. Thus, the +value indicates the first unused register in a given category. + +Normally, you would use @code{__builtin_args_info} in the implementation +of @code{va_start}, accessing each category just once and storing the +value in the @code{va_list} object. This is because @code{va_list} will +have to update the values, and there is no way to alter the +values accessed by @code{__builtin_args_info}. +@end defmac + +@defmac __builtin_next_arg (@var{lastarg}) +This is the equivalent of @code{__builtin_args_info}, for stack +arguments. It returns the address of the first anonymous stack +argument, as type @code{void *}. If @code{ARGS_GROW_DOWNWARD}, it +returns the address of the location above the first anonymous stack +argument. Use it in @code{va_start} to initialize the pointer for +fetching arguments from the stack. Also use it in @code{va_start} to +verify that the second parameter @var{lastarg} is the last named argument +of the current function. +@end defmac + +@defmac __builtin_classify_type (@var{object}) +Since each machine has its own conventions for which data types are +passed in which kind of register, your implementation of @code{va_arg} +has to embody these conventions. The easiest way to categorize the +specified data type is to use @code{__builtin_classify_type} together +with @code{sizeof} and @code{__alignof__}. + +@code{__builtin_classify_type} ignores the value of @var{object}, +considering only its data type. It returns an integer describing what +kind of type that is---integer, floating, pointer, structure, and so on. + +The file @file{typeclass.h} defines an enumeration that you can use to +interpret the values of @code{__builtin_classify_type}. +@end defmac + +These machine description macros help implement varargs: + +@deftypefn {Target Hook} rtx TARGET_EXPAND_BUILTIN_SAVEREGS (void) +If defined, this hook produces the machine-specific code for a call to +@code{__builtin_saveregs}. This code will be moved to the very +beginning of the function, before any parameter access are made. The +return value of this function should be an RTX that contains the value +to use as the return of @code{__builtin_saveregs}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SETUP_INCOMING_VARARGS (CUMULATIVE_ARGS *@var{args_so_far}, enum machine_mode @var{mode}, tree @var{type}, int *@var{pretend_args_size}, int @var{second_time}) +This target hook offers an alternative to using +@code{__builtin_saveregs} and defining the hook +@code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous +register arguments into the stack so that all the arguments appear to +have been passed consecutively on the stack. Once this is done, you can +use the standard implementation of varargs that works for machines that +pass all their arguments on the stack. + +The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data +structure, containing the values that are obtained after processing the +named arguments. The arguments @var{mode} and @var{type} describe the +last named argument---its machine mode and its data type as a tree node. + +The target hook should do two things: first, push onto the stack all the +argument registers @emph{not} used for the named arguments, and second, +store the size of the data thus pushed into the @code{int}-valued +variable pointed to by @var{pretend_args_size}. The value that you +store here will serve as additional offset for setting up the stack +frame. + +Because you must generate code to push the anonymous arguments at +compile time without knowing their data types, +@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that +have just a single category of argument register and use it uniformly +for all data types. + +If the argument @var{second_time} is nonzero, it means that the +arguments of the function are being analyzed for the second time. This +happens for an inline function, which is not actually compiled until the +end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should +not generate any instructions in this case. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_STRICT_ARGUMENT_NAMING (CUMULATIVE_ARGS *@var{ca}) +Define this hook to return @code{true} if the location where a function +argument is passed depends on whether or not it is a named argument. + +This hook controls how the @var{named} argument to @code{FUNCTION_ARG} +is set for varargs and stdarg functions. If this hook returns +@code{true}, the @var{named} argument is always true for named +arguments, and false for unnamed arguments. If it returns @code{false}, +but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true}, +then all arguments are treated as named. Otherwise, all named arguments +except the last are treated as named. + +You need not define this hook if it always returns zero. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_PRETEND_OUTGOING_VARARGS_NAMED +If you need to conditionally change ABIs so that one works with +@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither +@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was +defined, then define this hook to return @code{true} if +@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise. +Otherwise, you should not define this hook. +@end deftypefn + +@node Trampolines +@section Trampolines for Nested Functions +@cindex trampolines for nested functions +@cindex nested functions, trampolines for + +A @dfn{trampoline} is a small piece of code that is created at run time +when the address of a nested function is taken. It normally resides on +the stack, in the stack frame of the containing function. These macros +tell GCC how to generate code to allocate and initialize a +trampoline. + +The instructions in the trampoline must do two things: load a constant +address into the static chain register, and jump to the real address of +the nested function. On CISC machines such as the m68k, this requires +two instructions, a move immediate and a jump. Then the two addresses +exist in the trampoline as word-long immediate operands. On RISC +machines, it is often necessary to load each address into a register in +two parts. Then pieces of each address form separate immediate +operands. + +The code generated to initialize the trampoline must store the variable +parts---the static chain value and the function address---into the +immediate operands of the instructions. On a CISC machine, this is +simply a matter of copying each address to a memory reference at the +proper offset from the start of the trampoline. On a RISC machine, it +may be necessary to take out pieces of the address and store them +separately. + +@defmac TRAMPOLINE_TEMPLATE (@var{file}) +A C statement to output, on the stream @var{file}, assembler code for a +block of data that contains the constant parts of a trampoline. This +code should not include a label---the label is taken care of +automatically. + +If you do not define this macro, it means no template is needed +for the target. Do not define this macro on systems where the block move +code to copy the trampoline into place would be larger than the code +to generate it on the spot. +@end defmac + +@defmac TRAMPOLINE_SECTION +Return the section into which the trampoline template is to be placed +(@pxref{Sections}). The default value is @code{readonly_data_section}. +@end defmac + +@defmac TRAMPOLINE_SIZE +A C expression for the size in bytes of the trampoline, as an integer. +@end defmac + +@defmac TRAMPOLINE_ALIGNMENT +Alignment required for trampolines, in bits. + +If you don't define this macro, the value of @code{BIGGEST_ALIGNMENT} +is used for aligning trampolines. +@end defmac + +@defmac INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain}) +A C statement to initialize the variable parts of a trampoline. +@var{addr} is an RTX for the address of the trampoline; @var{fnaddr} is +an RTX for the address of the nested function; @var{static_chain} is an +RTX for the static chain value that should be passed to the function +when it is called. +@end defmac + +@defmac TRAMPOLINE_ADJUST_ADDRESS (@var{addr}) +A C statement that should perform any machine-specific adjustment in +the address of the trampoline. Its argument contains the address that +was passed to @code{INITIALIZE_TRAMPOLINE}. In case the address to be +used for a function call should be different from the address in which +the template was stored, the different address should be assigned to +@var{addr}. If this macro is not defined, @var{addr} will be used for +function calls. + +@cindex @code{TARGET_ASM_FUNCTION_EPILOGUE} and trampolines +@cindex @code{TARGET_ASM_FUNCTION_PROLOGUE} and trampolines +If this macro is not defined, by default the trampoline is allocated as +a stack slot. This default is right for most machines. The exceptions +are machines where it is impossible to execute instructions in the stack +area. On such machines, you may have to implement a separate stack, +using this macro in conjunction with @code{TARGET_ASM_FUNCTION_PROLOGUE} +and @code{TARGET_ASM_FUNCTION_EPILOGUE}. + +@var{fp} points to a data structure, a @code{struct function}, which +describes the compilation status of the immediate containing function of +the function which the trampoline is for. The stack slot for the +trampoline is in the stack frame of this containing function. Other +allocation strategies probably must do something analogous with this +information. +@end defmac + +Implementing trampolines is difficult on many machines because they have +separate instruction and data caches. Writing into a stack location +fails to clear the memory in the instruction cache, so when the program +jumps to that location, it executes the old contents. + +Here are two possible solutions. One is to clear the relevant parts of +the instruction cache whenever a trampoline is set up. The other is to +make all trampolines identical, by having them jump to a standard +subroutine. The former technique makes trampoline execution faster; the +latter makes initialization faster. + +To clear the instruction cache when a trampoline is initialized, define +the following macro. + +@defmac CLEAR_INSN_CACHE (@var{beg}, @var{end}) +If defined, expands to a C expression clearing the @emph{instruction +cache} in the specified interval. The definition of this macro would +typically be a series of @code{asm} statements. Both @var{beg} and +@var{end} are both pointer expressions. +@end defmac + +The operating system may also require the stack to be made executable +before calling the trampoline. To implement this requirement, define +the following macro. + +@defmac ENABLE_EXECUTE_STACK +Define this macro if certain operations must be performed before executing +code located on the stack. The macro should expand to a series of C +file-scope constructs (e.g.@: functions) and provide a unique entry point +named @code{__enable_execute_stack}. The target is responsible for +emitting calls to the entry point in the code, for example from the +@code{INITIALIZE_TRAMPOLINE} macro. +@end defmac + +To use a standard subroutine, define the following macro. In addition, +you must make sure that the instructions in a trampoline fill an entire +cache line with identical instructions, or else ensure that the +beginning of the trampoline code is always aligned at the same point in +its cache line. Look in @file{m68k.h} as a guide. + +@defmac TRANSFER_FROM_TRAMPOLINE +Define this macro if trampolines need a special subroutine to do their +work. The macro should expand to a series of @code{asm} statements +which will be compiled with GCC@. They go in a library function named +@code{__transfer_from_trampoline}. + +If you need to avoid executing the ordinary prologue code of a compiled +C function when you jump to the subroutine, you can do so by placing a +special label of your own in the assembler code. Use one @code{asm} +statement to generate an assembler label, and another to make the label +global. Then trampolines can use that label to jump directly to your +special assembler code. +@end defmac + +@node Library Calls +@section Implicit Calls to Library Routines +@cindex library subroutine names +@cindex @file{libgcc.a} + +@c prevent bad page break with this line +Here is an explanation of implicit calls to library routines. + +@defmac DECLARE_LIBRARY_RENAMES +This macro, if defined, should expand to a piece of C code that will get +expanded when compiling functions for libgcc.a. It can be used to +provide alternate names for GCC's internal library functions if there +are ABI-mandated names that the compiler should provide. +@end defmac + +@findex init_one_libfunc +@findex set_optab_libfunc +@deftypefn {Target Hook} void TARGET_INIT_LIBFUNCS (void) +This hook should declare additional library routines or rename +existing ones, using the functions @code{set_optab_libfunc} and +@code{init_one_libfunc} defined in @file{optabs.c}. +@code{init_optabs} calls this macro after initializing all the normal +library routines. + +The default is to do nothing. Most ports don't need to define this hook. +@end deftypefn + +@defmac FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison}) +This macro should return @code{true} if the library routine that +implements the floating point comparison operator @var{comparison} in +mode @var{mode} will return a boolean, and @var{false} if it will +return a tristate. + +GCC's own floating point libraries return tristates from the +comparison operators, so the default returns false always. Most ports +don't need to define this macro. +@end defmac + +@defmac TARGET_LIB_INT_CMP_BIASED +This macro should evaluate to @code{true} if the integer comparison +functions (like @code{__cmpdi2}) return 0 to indicate that the first +operand is smaller than the second, 1 to indicate that they are equal, +and 2 to indicate that the first operand is greater than the second. +If this macro evaluates to @code{false} the comparison functions return +@minus{}1, 0, and 1 instead of 0, 1, and 2. If the target uses the routines +in @file{libgcc.a}, you do not need to define this macro. +@end defmac + +@cindex US Software GOFAST, floating point emulation library +@cindex floating point emulation library, US Software GOFAST +@cindex GOFAST, floating point emulation library +@findex gofast_maybe_init_libfuncs +@defmac US_SOFTWARE_GOFAST +Define this macro if your system C library uses the US Software GOFAST +library to provide floating point emulation. + +In addition to defining this macro, your architecture must set +@code{TARGET_INIT_LIBFUNCS} to @code{gofast_maybe_init_libfuncs}, or +else call that function from its version of that hook. It is defined +in @file{config/gofast.h}, which must be included by your +architecture's @file{@var{cpu}.c} file. See @file{sparc/sparc.c} for +an example. + +If this macro is defined, the +@code{TARGET_FLOAT_LIB_COMPARE_RETURNS_BOOL} target hook must return +false for @code{SFmode} and @code{DFmode} comparisons. +@end defmac + +@cindex @code{EDOM}, implicit usage +@findex matherr +@defmac TARGET_EDOM +The value of @code{EDOM} on the target machine, as a C integer constant +expression. If you don't define this macro, GCC does not attempt to +deposit the value of @code{EDOM} into @code{errno} directly. Look in +@file{/usr/include/errno.h} to find the value of @code{EDOM} on your +system. + +If you do not define @code{TARGET_EDOM}, then compiled code reports +domain errors by calling the library function and letting it report the +error. If mathematical functions on your system use @code{matherr} when +there is an error, then you should leave @code{TARGET_EDOM} undefined so +that @code{matherr} is used normally. +@end defmac + +@cindex @code{errno}, implicit usage +@defmac GEN_ERRNO_RTX +Define this macro as a C expression to create an rtl expression that +refers to the global ``variable'' @code{errno}. (On certain systems, +@code{errno} may not actually be a variable.) If you don't define this +macro, a reasonable default is used. +@end defmac + +@cindex C99 math functions, implicit usage +@defmac TARGET_C99_FUNCTIONS +When this macro is nonzero, GCC will implicitly optimize @code{sin} calls into +@code{sinf} and similarly for other functions defined by C99 standard. The +default is nonzero that should be proper value for most modern systems, however +number of existing systems lacks support for these functions in the runtime so +they needs this macro to be redefined to 0. +@end defmac + +@defmac NEXT_OBJC_RUNTIME +Define this macro to generate code for Objective-C message sending using +the calling convention of the NeXT system. This calling convention +involves passing the object, the selector and the method arguments all +at once to the method-lookup library function. + +The default calling convention passes just the object and the selector +to the lookup function, which returns a pointer to the method. +@end defmac + +@node Addressing Modes +@section Addressing Modes +@cindex addressing modes + +@c prevent bad page break with this line +This is about addressing modes. + +@defmac HAVE_PRE_INCREMENT +@defmacx HAVE_PRE_DECREMENT +@defmacx HAVE_POST_INCREMENT +@defmacx HAVE_POST_DECREMENT +A C expression that is nonzero if the machine supports pre-increment, +pre-decrement, post-increment, or post-decrement addressing respectively. +@end defmac + +@defmac HAVE_PRE_MODIFY_DISP +@defmacx HAVE_POST_MODIFY_DISP +A C expression that is nonzero if the machine supports pre- or +post-address side-effect generation involving constants other than +the size of the memory operand. +@end defmac + +@defmac HAVE_PRE_MODIFY_REG +@defmacx HAVE_POST_MODIFY_REG +A C expression that is nonzero if the machine supports pre- or +post-address side-effect generation involving a register displacement. +@end defmac + +@defmac CONSTANT_ADDRESS_P (@var{x}) +A C expression that is 1 if the RTX @var{x} is a constant which +is a valid address. On most machines, this can be defined as +@code{CONSTANT_P (@var{x})}, but a few machines are more restrictive +in which constant addresses are supported. +@end defmac + +@defmac CONSTANT_P (@var{x}) +@code{CONSTANT_P}, which is defined by target-independent code, +accepts integer-values expressions whose values are not explicitly +known, such as @code{symbol_ref}, @code{label_ref}, and @code{high} +expressions and @code{const} arithmetic expressions, in addition to +@code{const_int} and @code{const_double} expressions. +@end defmac + +@defmac MAX_REGS_PER_ADDRESS +A number, the maximum number of registers that can appear in a valid +memory address. Note that it is up to you to specify a value equal to +the maximum number that @code{GO_IF_LEGITIMATE_ADDRESS} would ever +accept. +@end defmac + +@defmac GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label}) +A C compound statement with a conditional @code{goto @var{label};} +executed if @var{x} (an RTX) is a legitimate memory address on the +target machine for a memory operand of mode @var{mode}. + +It usually pays to define several simpler macros to serve as +subroutines for this one. Otherwise it may be too complicated to +understand. + +This macro must exist in two variants: a strict variant and a +non-strict one. The strict variant is used in the reload pass. It +must be defined so that any pseudo-register that has not been +allocated a hard register is considered a memory reference. In +contexts where some kind of register is required, a pseudo-register +with no hard register must be rejected. + +The non-strict variant is used in other passes. It must be defined to +accept all pseudo-registers in every context where some kind of +register is required. + +@findex REG_OK_STRICT +Compiler source files that want to use the strict variant of this +macro define the macro @code{REG_OK_STRICT}. You should use an +@code{#ifdef REG_OK_STRICT} conditional to define the strict variant +in that case and the non-strict variant otherwise. + +Subroutines to check for acceptable registers for various purposes (one +for base registers, one for index registers, and so on) are typically +among the subroutines used to define @code{GO_IF_LEGITIMATE_ADDRESS}. +Then only these subroutine macros need have two variants; the higher +levels of macros may be the same whether strict or not. + +Normally, constant addresses which are the sum of a @code{symbol_ref} +and an integer are stored inside a @code{const} RTX to mark them as +constant. Therefore, there is no need to recognize such sums +specifically as legitimate addresses. Normally you would simply +recognize any @code{const} as legitimate. + +Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant +sums that are not marked with @code{const}. It assumes that a naked +@code{plus} indicates indexing. If so, then you @emph{must} reject such +naked constant sums as illegitimate addresses, so that none of them will +be given to @code{PRINT_OPERAND_ADDRESS}. + +@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation +On some machines, whether a symbolic address is legitimate depends on +the section that the address refers to. On these machines, define the +target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information +into the @code{symbol_ref}, and then check for it here. When you see a +@code{const}, you will have to look inside it to find the +@code{symbol_ref} in order to determine the section. @xref{Assembler +Format}. +@end defmac + +@defmac FIND_BASE_TERM (@var{x}) +A C expression to determine the base term of address @var{x}. +This macro is used in only one place: `find_base_term' in alias.c. + +It is always safe for this macro to not be defined. It exists so +that alias analysis can understand machine-dependent addresses. + +The typical use of this macro is to handle addresses containing +a label_ref or symbol_ref within an UNSPEC@. +@end defmac + +@defmac LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win}) +A C compound statement that attempts to replace @var{x} with a valid +memory address for an operand of mode @var{mode}. @var{win} will be a +C statement label elsewhere in the code; the macro definition may use + +@smallexample +GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{win}); +@end smallexample + +@noindent +to avoid further processing if the address has become legitimate. + +@findex break_out_memory_refs +@var{x} will always be the result of a call to @code{break_out_memory_refs}, +and @var{oldx} will be the operand that was given to that function to produce +@var{x}. + +The code generated by this macro should not alter the substructure of +@var{x}. If it transforms @var{x} into a more legitimate form, it +should assign @var{x} (which will always be a C variable) a new value. + +It is not necessary for this macro to come up with a legitimate +address. The compiler has standard ways of doing so in all cases. In +fact, it is safe to omit this macro. But often a +machine-dependent strategy can generate better code. +@end defmac + +@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win}) +A C compound statement that attempts to replace @var{x}, which is an address +that needs reloading, with a valid memory address for an operand of mode +@var{mode}. @var{win} will be a C statement label elsewhere in the code. +It is not necessary to define this macro, but it might be useful for +performance reasons. + +For example, on the i386, it is sometimes possible to use a single +reload register instead of two by reloading a sum of two pseudo +registers into a register. On the other hand, for number of RISC +processors offsets are limited so that often an intermediate address +needs to be generated in order to address a stack slot. By defining +@code{LEGITIMIZE_RELOAD_ADDRESS} appropriately, the intermediate addresses +generated for adjacent some stack slots can be made identical, and thus +be shared. + +@emph{Note}: This macro should be used with caution. It is necessary +to know something of how reload works in order to effectively use this, +and it is quite easy to produce macros that build in too much knowledge +of reload internals. + +@emph{Note}: This macro must be able to reload an address created by a +previous invocation of this macro. If it fails to handle such addresses +then the compiler may generate incorrect code or abort. + +@findex push_reload +The macro definition should use @code{push_reload} to indicate parts that +need reloading; @var{opnum}, @var{type} and @var{ind_levels} are usually +suitable to be passed unaltered to @code{push_reload}. + +The code generated by this macro must not alter the substructure of +@var{x}. If it transforms @var{x} into a more legitimate form, it +should assign @var{x} (which will always be a C variable) a new value. +This also applies to parts that you change indirectly by calling +@code{push_reload}. + +@findex strict_memory_address_p +The macro definition may use @code{strict_memory_address_p} to test if +the address has become legitimate. + +@findex copy_rtx +If you want to change only a part of @var{x}, one standard way of doing +this is to use @code{copy_rtx}. Note, however, that is unshares only a +single level of rtl. Thus, if the part to be changed is not at the +top level, you'll need to replace first the top level. +It is not necessary for this macro to come up with a legitimate +address; but often a machine-dependent strategy can generate better code. +@end defmac + +@defmac GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label}) +A C statement or compound statement with a conditional @code{goto +@var{label};} executed if memory address @var{x} (an RTX) can have +different meanings depending on the machine mode of the memory +reference it is used for or if the address is valid for some modes +but not others. + +Autoincrement and autodecrement addresses typically have mode-dependent +effects because the amount of the increment or decrement is the size +of the operand being addressed. Some machines have other mode-dependent +addresses. Many RISC machines have no mode-dependent addresses. + +You may assume that @var{addr} is a valid address for the machine. +@end defmac + +@defmac LEGITIMATE_CONSTANT_P (@var{x}) +A C expression that is nonzero if @var{x} is a legitimate constant for +an immediate operand on the target machine. You can assume that +@var{x} satisfies @code{CONSTANT_P}, so you need not check this. In fact, +@samp{1} is a suitable definition for this macro on machines where +anything @code{CONSTANT_P} is valid. +@end defmac + +@deftypefn {Target Hook} rtx TARGET_DELEGITIMIZE_ADDRESS (rtx @var{x}) +This hook is used to undo the possibly obfuscating effects of the +@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target +macros. Some backend implementations of these macros wrap symbol +references inside an @code{UNSPEC} rtx to represent PIC or similar +addressing modes. This target hook allows GCC's optimizers to understand +the semantics of these opaque @code{UNSPEC}s by converting them back +into their original form. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CANNOT_FORCE_CONST_MEM (rtx @var{x}) +This hook should return true if @var{x} is of a form that cannot (or +should not) be spilled to the constant pool. The default version of +this hook returns false. + +The primary reason to define this hook is to prevent reload from +deciding that a non-legitimate constant would be better reloaded +from the constant pool instead of spilling and reloading a register +holding the constant. This restriction is often true of addresses +of TLS symbols for various targets. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_USE_BLOCKS_FOR_CONSTANT_P (enum machine_mode @var{mode}, rtx @var{x}) +This hook should return true if pool entries for constant @var{x} can +be placed in an @code{object_block} structure. @var{mode} is the mode +of @var{x}. + +The default version returns false for all constants. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void) +This hook should return the DECL of a function @var{f} that given an +address @var{addr} as an argument returns a mask @var{m} that can be +used to extract from two vectors the relevant data that resides in +@var{addr} in case @var{addr} is not properly aligned. + +The autovectrizer, when vectorizing a load operation from an address +@var{addr} that may be unaligned, will generate two vector loads from +the two aligned addresses around @var{addr}. It then generates a +@code{REALIGN_LOAD} operation to extract the relevant data from the +two loaded vectors. The first two arguments to @code{REALIGN_LOAD}, +@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and +the third argument, @var{OFF}, defines how the data will be extracted +from these two vectors: if @var{OFF} is 0, then the returned vector is +@var{v2}; otherwise, the returned vector is composed from the last +@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first +@var{OFF} elements of @var{v2}. + +If this hook is defined, the autovectorizer will generate a call +to @var{f} (using the DECL tree that this hook returns) and will +use the return value of @var{f} as the argument @var{OFF} to +@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f} +should comply with the semantics expected by @code{REALIGN_LOAD} +described above. +If this hook is not defined, then @var{addr} will be used as +the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low +log2(@var{VS})-1 bits of @var{addr} will be considered. +@end deftypefn + +@node Anchored Addresses +@section Anchored Addresses +@cindex anchored addresses +@cindex @option{-fsection-anchors} + +GCC usually addresses every static object as a separate entity. +For example, if we have: + +@smallexample +static int a, b, c; +int foo (void) @{ return a + b + c; @} +@end smallexample + +the code for @code{foo} will usually calculate three separate symbolic +addresses: those of @code{a}, @code{b} and @code{c}. On some targets, +it would be better to calculate just one symbolic address and access +the three variables relative to it. The equivalent pseudocode would +be something like: + +@smallexample +int foo (void) +@{ + register int *xr = &x; + return xr[&a - &x] + xr[&b - &x] + xr[&c - &x]; +@} +@end smallexample + +(which isn't valid C). We refer to shared addresses like @code{x} as +``section anchors''. Their use is controlled by @option{-fsection-anchors}. + +The hooks below describe the target properties that GCC needs to know +in order to make effective use of section anchors. It won't use +section anchors at all unless either @code{TARGET_MIN_ANCHOR_OFFSET} +or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value. + +@deftypevar {Target Hook} HOST_WIDE_INT TARGET_MIN_ANCHOR_OFFSET +The minimum offset that should be applied to a section anchor. +On most targets, it should be the smallest offset that can be +applied to a base register while still giving a legitimate address +for every mode. The default value is 0. +@end deftypevar + +@deftypevar {Target Hook} HOST_WIDE_INT TARGET_MAX_ANCHOR_OFFSET +Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive) +offset that should be applied to section anchors. The default +value is 0. +@end deftypevar + +@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_ANCHOR (rtx @var{x}) +Write the assembly code to define section anchor @var{x}, which is a +@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true. +The hook is called with the assembly output position set to the beginning +of @code{SYMBOL_REF_BLOCK (@var{x})}. + +If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses +it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}. +If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition +is @code{NULL}, which disables the use of section anchors altogether. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_USE_ANCHORS_FOR_SYMBOL_P (rtx @var{x}) +Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF} +@var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and +@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}. + +The default version is correct for most targets, but you might need to +intercept this hook to handle things like target-specific attributes +or target-specific sections. +@end deftypefn + +@node Condition Code +@section Condition Code Status +@cindex condition code status + +@c prevent bad page break with this line +This describes the condition code status. + +@findex cc_status +The file @file{conditions.h} defines a variable @code{cc_status} to +describe how the condition code was computed (in case the interpretation of +the condition code depends on the instruction that it was set by). This +variable contains the RTL expressions on which the condition code is +currently based, and several standard flags. + +Sometimes additional machine-specific flags must be defined in the machine +description header file. It can also add additional machine-specific +information by defining @code{CC_STATUS_MDEP}. + +@defmac CC_STATUS_MDEP +C code for a data type which is used for declaring the @code{mdep} +component of @code{cc_status}. It defaults to @code{int}. + +This macro is not used on machines that do not use @code{cc0}. +@end defmac + +@defmac CC_STATUS_MDEP_INIT +A C expression to initialize the @code{mdep} field to ``empty''. +The default definition does nothing, since most machines don't use +the field anyway. If you want to use the field, you should probably +define this macro to initialize it. + +This macro is not used on machines that do not use @code{cc0}. +@end defmac + +@defmac NOTICE_UPDATE_CC (@var{exp}, @var{insn}) +A C compound statement to set the components of @code{cc_status} +appropriately for an insn @var{insn} whose body is @var{exp}. It is +this macro's responsibility to recognize insns that set the condition +code as a byproduct of other activity as well as those that explicitly +set @code{(cc0)}. + +This macro is not used on machines that do not use @code{cc0}. + +If there are insns that do not set the condition code but do alter +other machine registers, this macro must check to see whether they +invalidate the expressions that the condition code is recorded as +reflecting. For example, on the 68000, insns that store in address +registers do not set the condition code, which means that usually +@code{NOTICE_UPDATE_CC} can leave @code{cc_status} unaltered for such +insns. But suppose that the previous insn set the condition code +based on location @samp{a4@@(102)} and the current insn stores a new +value in @samp{a4}. Although the condition code is not changed by +this, it will no longer be true that it reflects the contents of +@samp{a4@@(102)}. Therefore, @code{NOTICE_UPDATE_CC} must alter +@code{cc_status} in this case to say that nothing is known about the +condition code value. + +The definition of @code{NOTICE_UPDATE_CC} must be prepared to deal +with the results of peephole optimization: insns whose patterns are +@code{parallel} RTXs containing various @code{reg}, @code{mem} or +constants which are just the operands. The RTL structure of these +insns is not sufficient to indicate what the insns actually do. What +@code{NOTICE_UPDATE_CC} should do when it sees one is just to run +@code{CC_STATUS_INIT}. + +A possible definition of @code{NOTICE_UPDATE_CC} is to call a function +that looks at an attribute (@pxref{Insn Attributes}) named, for example, +@samp{cc}. This avoids having detailed information about patterns in +two places, the @file{md} file and in @code{NOTICE_UPDATE_CC}. +@end defmac + +@defmac SELECT_CC_MODE (@var{op}, @var{x}, @var{y}) +Returns a mode from class @code{MODE_CC} to be used when comparison +operation code @var{op} is applied to rtx @var{x} and @var{y}. For +example, on the SPARC, @code{SELECT_CC_MODE} is defined as (see +@pxref{Jump Patterns} for a description of the reason for this +definition) + +@smallexample +#define SELECT_CC_MODE(OP,X,Y) \ + (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \ + ? ((OP == EQ || OP == NE) ? CCFPmode : CCFPEmode) \ + : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \ + || GET_CODE (X) == NEG) \ + ? CC_NOOVmode : CCmode)) +@end smallexample + +You should define this macro if and only if you define extra CC modes +in @file{@var{machine}-modes.def}. +@end defmac + +@defmac CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1}) +On some machines not all possible comparisons are defined, but you can +convert an invalid comparison into a valid one. For example, the Alpha +does not have a @code{GT} comparison, but you can use an @code{LT} +comparison instead and swap the order of the operands. + +On such machines, define this macro to be a C statement to do any +required conversions. @var{code} is the initial comparison code +and @var{op0} and @var{op1} are the left and right operands of the +comparison, respectively. You should modify @var{code}, @var{op0}, and +@var{op1} as required. + +GCC will not assume that the comparison resulting from this macro is +valid but will see if the resulting insn matches a pattern in the +@file{md} file. + +You need not define this macro if it would never change the comparison +code or operands. +@end defmac + +@defmac REVERSIBLE_CC_MODE (@var{mode}) +A C expression whose value is one if it is always safe to reverse a +comparison whose mode is @var{mode}. If @code{SELECT_CC_MODE} +can ever return @var{mode} for a floating-point inequality comparison, +then @code{REVERSIBLE_CC_MODE (@var{mode})} must be zero. + +You need not define this macro if it would always returns zero or if the +floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}. +For example, here is the definition used on the SPARC, where floating-point +inequality comparisons are always given @code{CCFPEmode}: + +@smallexample +#define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode) +@end smallexample +@end defmac + +@defmac REVERSE_CONDITION (@var{code}, @var{mode}) +A C expression whose value is reversed condition code of the @var{code} for +comparison done in CC_MODE @var{mode}. The macro is used only in case +@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case +machine has some non-standard way how to reverse certain conditionals. For +instance in case all floating point conditions are non-trapping, compiler may +freely convert unordered compares to ordered one. Then definition may look +like: + +@smallexample +#define REVERSE_CONDITION(CODE, MODE) \ + ((MODE) != CCFPmode ? reverse_condition (CODE) \ + : reverse_condition_maybe_unordered (CODE)) +@end smallexample +@end defmac + +@defmac REVERSE_CONDEXEC_PREDICATES_P (@var{op1}, @var{op2}) +A C expression that returns true if the conditional execution predicate +@var{op1}, a comparison operation, is the inverse of @var{op2} and vice +versa. Define this to return 0 if the target has conditional execution +predicates that cannot be reversed safely. There is no need to validate +that the arguments of op1 and op2 are the same, this is done separately. +If no expansion is specified, this macro is defined as follows: + +@smallexample +#define REVERSE_CONDEXEC_PREDICATES_P (x, y) \ + (GET_CODE ((x)) == reversed_comparison_code ((y), NULL)) +@end smallexample +@end defmac + +@deftypefn {Target Hook} bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int *, unsigned int *) +On targets which do not use @code{(cc0)}, and which use a hard +register rather than a pseudo-register to hold condition codes, the +regular CSE passes are often not able to identify cases in which the +hard register is set to a common value. Use this hook to enable a +small pass which optimizes such cases. This hook should return true +to enable this pass, and it should set the integers to which its +arguments point to the hard register numbers used for condition codes. +When there is only one such register, as is true on most systems, the +integer pointed to by the second argument should be set to +@code{INVALID_REGNUM}. + +The default version of this hook returns false. +@end deftypefn + +@deftypefn {Target Hook} enum machine_mode TARGET_CC_MODES_COMPATIBLE (enum machine_mode, enum machine_mode) +On targets which use multiple condition code modes in class +@code{MODE_CC}, it is sometimes the case that a comparison can be +validly done in more than one mode. On such a system, define this +target hook to take two mode arguments and to return a mode in which +both comparisons may be validly done. If there is no such mode, +return @code{VOIDmode}. + +The default version of this hook checks whether the modes are the +same. If they are, it returns that mode. If they are different, it +returns @code{VOIDmode}. +@end deftypefn + +@node Costs +@section Describing Relative Costs of Operations +@cindex costs of instructions +@cindex relative costs +@cindex speed of instructions + +These macros let you describe the relative speed of various operations +on the target machine. + +@defmac REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to}) +A C expression for the cost of moving data of mode @var{mode} from a +register in class @var{from} to one in class @var{to}. The classes are +expressed using the enumeration values such as @code{GENERAL_REGS}. A +value of 2 is the default; other values are interpreted relative to +that. + +It is not required that the cost always equal 2 when @var{from} is the +same as @var{to}; on some machines it is expensive to move between +registers if they are not general registers. + +If reload sees an insn consisting of a single @code{set} between two +hard registers, and if @code{REGISTER_MOVE_COST} applied to their +classes returns a value of 2, reload does not check to ensure that the +constraints of the insn are met. Setting a cost of other than 2 will +allow reload to verify that the constraints are met. You should do this +if the @samp{mov@var{m}} pattern's constraints do not allow such copying. +@end defmac + +@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in}) +A C expression for the cost of moving data of mode @var{mode} between a +register of class @var{class} and memory; @var{in} is zero if the value +is to be written to memory, nonzero if it is to be read in. This cost +is relative to those in @code{REGISTER_MOVE_COST}. If moving between +registers and memory is more expensive than between two registers, you +should define this macro to express the relative cost. + +If you do not define this macro, GCC uses a default cost of 4 plus +the cost of copying via a secondary reload register, if one is +needed. If your machine requires a secondary reload register to copy +between memory and a register of @var{class} but the reload mechanism is +more complex than copying via an intermediate, define this macro to +reflect the actual cost of the move. + +GCC defines the function @code{memory_move_secondary_cost} if +secondary reloads are needed. It computes the costs due to copying via +a secondary register. If your machine copies from memory using a +secondary register in the conventional way but the default base value of +4 is not correct for your machine, define this macro to add some other +value to the result of that function. The arguments to that function +are the same as to this macro. +@end defmac + +@defmac BRANCH_COST +A C expression for the cost of a branch instruction. A value of 1 is +the default; other values are interpreted relative to that. +@end defmac + +Here are additional macros which do not specify precise relative costs, +but only that certain actions are more expensive than GCC would +ordinarily expect. + +@defmac SLOW_BYTE_ACCESS +Define this macro as a C expression which is nonzero if accessing less +than a word of memory (i.e.@: a @code{char} or a @code{short}) is no +faster than accessing a word of memory, i.e., if such access +require more than one instruction or if there is no difference in cost +between byte and (aligned) word loads. + +When this macro is not defined, the compiler will access a field by +finding the smallest containing object; when it is defined, a fullword +load will be used if alignment permits. Unless bytes accesses are +faster than word accesses, using word accesses is preferable since it +may eliminate subsequent memory access if subsequent accesses occur to +other fields in the same word of the structure, but to different bytes. +@end defmac + +@defmac SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment}) +Define this macro to be the value 1 if memory accesses described by the +@var{mode} and @var{alignment} parameters have a cost many times greater +than aligned accesses, for example if they are emulated in a trap +handler. + +When this macro is nonzero, the compiler will act as if +@code{STRICT_ALIGNMENT} were nonzero when generating code for block +moves. This can cause significantly more instructions to be produced. +Therefore, do not set this macro nonzero if unaligned accesses only add a +cycle or two to the time for a memory access. + +If the value of this macro is always zero, it need not be defined. If +this macro is defined, it should produce a nonzero value when +@code{STRICT_ALIGNMENT} is nonzero. +@end defmac + +@defmac MOVE_RATIO +The threshold of number of scalar memory-to-memory move insns, @emph{below} +which a sequence of insns should be generated instead of a +string move insn or a library call. Increasing the value will always +make code faster, but eventually incurs high cost in increased code size. + +Note that on machines where the corresponding move insn is a +@code{define_expand} that emits a sequence of insns, this macro counts +the number of such sequences. + +If you don't define this, a reasonable default is used. +@end defmac + +@defmac MOVE_BY_PIECES_P (@var{size}, @var{alignment}) +A C expression used to determine whether @code{move_by_pieces} will be used to +copy a chunk of memory, or whether some other block move mechanism +will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less +than @code{MOVE_RATIO}. +@end defmac + +@defmac MOVE_MAX_PIECES +A C expression used by @code{move_by_pieces} to determine the largest unit +a load or store used to copy memory is. Defaults to @code{MOVE_MAX}. +@end defmac + +@defmac CLEAR_RATIO +The threshold of number of scalar move insns, @emph{below} which a sequence +of insns should be generated to clear memory instead of a string clear insn +or a library call. Increasing the value will always make code faster, but +eventually incurs high cost in increased code size. + +If you don't define this, a reasonable default is used. +@end defmac + +@defmac CLEAR_BY_PIECES_P (@var{size}, @var{alignment}) +A C expression used to determine whether @code{clear_by_pieces} will be used +to clear a chunk of memory, or whether some other block clear mechanism +will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less +than @code{CLEAR_RATIO}. +@end defmac + +@defmac STORE_BY_PIECES_P (@var{size}, @var{alignment}) +A C expression used to determine whether @code{store_by_pieces} will be +used to set a chunk of memory to a constant value, or whether some other +mechanism will be used. Used by @code{__builtin_memset} when storing +values other than constant zero and by @code{__builtin_strcpy} when +when called with a constant source string. +Defaults to 1 if @code{move_by_pieces_ninsns} returns less +than @code{MOVE_RATIO}. +@end defmac + +@defmac USE_LOAD_POST_INCREMENT (@var{mode}) +A C expression used to determine whether a load postincrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_POST_INCREMENT}. +@end defmac + +@defmac USE_LOAD_POST_DECREMENT (@var{mode}) +A C expression used to determine whether a load postdecrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_POST_DECREMENT}. +@end defmac + +@defmac USE_LOAD_PRE_INCREMENT (@var{mode}) +A C expression used to determine whether a load preincrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_PRE_INCREMENT}. +@end defmac + +@defmac USE_LOAD_PRE_DECREMENT (@var{mode}) +A C expression used to determine whether a load predecrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_PRE_DECREMENT}. +@end defmac + +@defmac USE_STORE_POST_INCREMENT (@var{mode}) +A C expression used to determine whether a store postincrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_POST_INCREMENT}. +@end defmac + +@defmac USE_STORE_POST_DECREMENT (@var{mode}) +A C expression used to determine whether a store postdecrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_POST_DECREMENT}. +@end defmac + +@defmac USE_STORE_PRE_INCREMENT (@var{mode}) +This macro is used to determine whether a store preincrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_PRE_INCREMENT}. +@end defmac + +@defmac USE_STORE_PRE_DECREMENT (@var{mode}) +This macro is used to determine whether a store predecrement is a good +thing to use for a given mode. Defaults to the value of +@code{HAVE_PRE_DECREMENT}. +@end defmac + +@defmac NO_FUNCTION_CSE +Define this macro if it is as good or better to call a constant +function address than to call an address kept in a register. +@end defmac + +@defmac RANGE_TEST_NON_SHORT_CIRCUIT +Define this macro if a non-short-circuit operation produced by +@samp{fold_range_test ()} is optimal. This macro defaults to true if +@code{BRANCH_COST} is greater than or equal to the value 2. +@end defmac + +@deftypefn {Target Hook} bool TARGET_RTX_COSTS (rtx @var{x}, int @var{code}, int @var{outer_code}, int *@var{total}) +This target hook describes the relative costs of RTL expressions. + +The cost may depend on the precise form of the expression, which is +available for examination in @var{x}, and the rtx code of the expression +in which it is contained, found in @var{outer_code}. @var{code} is the +expression code---redundant, since it can be obtained with +@code{GET_CODE (@var{x})}. + +In implementing this hook, you can use the construct +@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast +instructions. + +On entry to the hook, @code{*@var{total}} contains a default estimate +for the cost of the expression. The hook should modify this value as +necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)} +for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus +operations, and @code{COSTS_N_INSNS (1)} for all other operations. + +When optimizing for code size, i.e.@: when @code{optimize_size} is +nonzero, this target hook should be used to estimate the relative +size cost of an expression, again relative to @code{COSTS_N_INSNS}. + +The hook returns true when all subexpressions of @var{x} have been +processed, and false when @code{rtx_cost} should recurse. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_ADDRESS_COST (rtx @var{address}) +This hook computes the cost of an addressing mode that contains +@var{address}. If not defined, the cost is computed from +the @var{address} expression and the @code{TARGET_RTX_COST} hook. + +For most CISC machines, the default cost is a good approximation of the +true cost of the addressing mode. However, on RISC machines, all +instructions normally have the same length and execution time. Hence +all addresses will have equal costs. + +In cases where more than one form of an address is known, the form with +the lowest cost will be used. If multiple forms have the same, lowest, +cost, the one that is the most complex will be used. + +For example, suppose an address that is equal to the sum of a register +and a constant is used twice in the same basic block. When this macro +is not defined, the address will be computed in a register and memory +references will be indirect through that register. On machines where +the cost of the addressing mode containing the sum is no higher than +that of a simple indirect reference, this will produce an additional +instruction and possibly require an additional register. Proper +specification of this macro eliminates this overhead for such machines. + +This hook is never called with an invalid address. + +On machines where an address involving more than one register is as +cheap as an address computation involving only one register, defining +@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to +be live over a region of code where only one would have been if +@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect +should be considered in the definition of this macro. Equivalent costs +should probably only be given to addresses with different numbers of +registers on machines with lots of registers. +@end deftypefn + +@node Scheduling +@section Adjusting the Instruction Scheduler + +The instruction scheduler may need a fair amount of machine-specific +adjustment in order to produce good code. GCC provides several target +hooks for this purpose. It is usually enough to define just a few of +them: try the first ones in this list first. + +@deftypefn {Target Hook} int TARGET_SCHED_ISSUE_RATE (void) +This hook returns the maximum number of instructions that can ever +issue at the same time on the target machine. The default is one. +Although the insn scheduler can define itself the possibility of issue +an insn on the same cycle, the value can serve as an additional +constraint to issue insns on the same simulated processor cycle (see +hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}). +This value must be constant over the entire compilation. If you need +it to vary depending on what the instructions are, you must use +@samp{TARGET_SCHED_VARIABLE_ISSUE}. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more}) +This hook is executed by the scheduler after it has scheduled an insn +from the ready list. It should return the number of insns which can +still be issued in the current cycle. The default is +@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and +@code{USE}, which normally are not counted against the issue rate. +You should define this hook if some insns take more machine resources +than others, so that fewer insns can follow them in the same cycle. +@var{file} is either a null pointer, or a stdio stream to write any +debug output to. @var{verbose} is the verbose level provided by +@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that +was scheduled. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST (rtx @var{insn}, rtx @var{link}, rtx @var{dep_insn}, int @var{cost}) +This function corrects the value of @var{cost} based on the +relationship between @var{insn} and @var{dep_insn} through the +dependence @var{link}. It should return the new value. The default +is to make no adjustment to @var{cost}. This can be used for example +to specify to the scheduler using the traditional pipeline description +that an output- or anti-dependence does not incur the same cost as a +data-dependence. If the scheduler using the automaton based pipeline +description, the cost of anti-dependence is zero and the cost of +output-dependence is maximum of one and the difference of latency +times of the first and the second insns. If these values are not +acceptable, you could use the hook to modify them too. See also +@pxref{Processor pipeline description}. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_PRIORITY (rtx @var{insn}, int @var{priority}) +This hook adjusts the integer scheduling priority @var{priority} of +@var{insn}. It should return the new priority. Increase the priority to +execute @var{insn} earlier, reduce the priority to execute @var{insn} +later. Do not define this hook if you do not need to adjust the +scheduling priorities of insns. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_REORDER (FILE *@var{file}, int @var{verbose}, rtx *@var{ready}, int *@var{n_readyp}, int @var{clock}) +This hook is executed by the scheduler after it has scheduled the ready +list, to allow the machine description to reorder it (for example to +combine two small instructions together on @samp{VLIW} machines). +@var{file} is either a null pointer, or a stdio stream to write any +debug output to. @var{verbose} is the verbose level provided by +@option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready +list of instructions that are ready to be scheduled. @var{n_readyp} is +a pointer to the number of elements in the ready list. The scheduler +reads the ready list in reverse order, starting with +@var{ready}[@var{*n_readyp}-1] and going to @var{ready}[0]. @var{clock} +is the timer tick of the scheduler. You may modify the ready list and +the number of ready insns. The return value is the number of insns that +can issue this cycle; normally this is just @code{issue_rate}. See also +@samp{TARGET_SCHED_REORDER2}. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_REORDER2 (FILE *@var{file}, int @var{verbose}, rtx *@var{ready}, int *@var{n_ready}, @var{clock}) +Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That +function is called whenever the scheduler starts a new cycle. This one +is called once per iteration over a cycle, immediately after +@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and +return the number of insns to be scheduled in the same cycle. Defining +this hook can be useful if there are frequent situations where +scheduling one insn causes other insns to become ready in the same +cycle. These other insns can then be taken into account properly. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK (rtx @var{head}, rtx @var{tail}) +This hook is called after evaluation forward dependencies of insns in +chain given by two parameter values (@var{head} and @var{tail} +correspondingly) but before insns scheduling of the insn chain. For +example, it can be used for better insn classification if it requires +analysis of dependencies. This hook can use backward and forward +dependencies of the insn scheduler because they are already +calculated. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_INIT (FILE *@var{file}, int @var{verbose}, int @var{max_ready}) +This hook is executed by the scheduler at the beginning of each block of +instructions that are to be scheduled. @var{file} is either a null +pointer, or a stdio stream to write any debug output to. @var{verbose} +is the verbose level provided by @option{-fsched-verbose-@var{n}}. +@var{max_ready} is the maximum number of insns in the current scheduling +region that can be live at the same time. This can be used to allocate +scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_FINISH (FILE *@var{file}, int @var{verbose}) +This hook is executed by the scheduler at the end of each block of +instructions that are to be scheduled. It can be used to perform +cleanup of any actions done by the other scheduling hooks. @var{file} +is either a null pointer, or a stdio stream to write any debug output +to. @var{verbose} is the verbose level provided by +@option{-fsched-verbose-@var{n}}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_INIT_GLOBAL (FILE *@var{file}, int @var{verbose}, int @var{old_max_uid}) +This hook is executed by the scheduler after function level initializations. +@var{file} is either a null pointer, or a stdio stream to write any debug output to. +@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}. +@var{old_max_uid} is the maximum insn uid when scheduling begins. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_FINISH_GLOBAL (FILE *@var{file}, int @var{verbose}) +This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}. +@var{file} is either a null pointer, or a stdio stream to write any debug output to. +@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_DFA_PRE_CYCLE_INSN (void) +The hook returns an RTL insn. The automaton state used in the +pipeline hazard recognizer is changed as if the insn were scheduled +when the new simulated processor cycle starts. Usage of the hook may +simplify the automaton pipeline description for some @acronym{VLIW} +processors. If the hook is defined, it is used only for the automaton +based pipeline description. The default is not to change the state +when the new simulated processor cycle starts. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN (void) +The hook can be used to initialize data used by the previous hook. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_DFA_POST_CYCLE_INSN (void) +The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used +to changed the state as if the insn were scheduled when the new +simulated processor cycle finishes. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN (void) +The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but +used to initialize data used by the previous hook. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD (void) +This hook controls better choosing an insn from the ready insn queue +for the @acronym{DFA}-based insn scheduler. Usually the scheduler +chooses the first insn from the queue. If the hook returns a positive +value, an additional scheduler code tries all permutations of +@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()} +subsequent ready insns to choose an insn whose issue will result in +maximal number of issued insns on the same cycle. For the +@acronym{VLIW} processor, the code could actually solve the problem of +packing simple insns into the @acronym{VLIW} insn. Of course, if the +rules of @acronym{VLIW} packing are described in the automaton. + +This code also could be used for superscalar @acronym{RISC} +processors. Let us consider a superscalar @acronym{RISC} processor +with 3 pipelines. Some insns can be executed in pipelines @var{A} or +@var{B}, some insns can be executed only in pipelines @var{B} or +@var{C}, and one insn can be executed in pipeline @var{B}. The +processor may issue the 1st insn into @var{A} and the 2nd one into +@var{B}. In this case, the 3rd insn will wait for freeing @var{B} +until the next cycle. If the scheduler issues the 3rd insn the first, +the processor could issue all 3 insns per cycle. + +Actually this code demonstrates advantages of the automaton based +pipeline hazard recognizer. We try quickly and easy many insn +schedules to choose the best one. + +The default is no multipass scheduling. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD (rtx) + +This hook controls what insns from the ready insn queue will be +considered for the multipass insn scheduling. If the hook returns +zero for insn passed as the parameter, the insn will be not chosen to +be issued. + +The default is that any ready insns can be chosen to be issued. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_DFA_NEW_CYCLE (FILE *, int, rtx, int, int, int *) + +This hook is called by the insn scheduler before issuing insn passed +as the third parameter on given cycle. If the hook returns nonzero, +the insn is not issued on given processors cycle. Instead of that, +the processor cycle is advanced. If the value passed through the last +parameter is zero, the insn ready queue is not sorted on the new cycle +start as usually. The first parameter passes file for debugging +output. The second one passes the scheduler verbose level of the +debugging output. The forth and the fifth parameter values are +correspondingly processor cycle on which the previous insn has been +issued and the current processor cycle. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (rtx @var{insn1}, rtx @var{insn2}, rtx @var{dep_link}, int @var{dep_cost}, int @var{distance}) +This hook is used to define which dependences are considered costly by +the target, so costly that it is not advisable to schedule the insns that +are involved in the dependence too close to one another. The parameters +to this hook are as follows: The second parameter @var{insn2} is dependent +upon the first parameter @var{insn1}. The dependence between @var{insn1} +and @var{insn2} is represented by the third parameter @var{dep_link}. The +fourth parameter @var{cost} is the cost of the dependence, and the fifth +parameter @var{distance} is the distance in cycles between the two insns. +The hook returns @code{true} if considering the distance between the two +insns the dependence between them is considered costly by the target, +and @code{false} otherwise. + +Defining this hook can be useful in multiple-issue out-of-order machines, +where (a) it's practically hopeless to predict the actual data/resource +delays, however: (b) there's a better chance to predict the actual grouping +that will be formed, and (c) correctly emulating the grouping can be very +important. In such targets one may want to allow issuing dependent insns +closer to one another---i.e., closer than the dependence distance; however, +not in cases of "costly dependences", which this hooks allows to define. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST_2 (rtx @var{insn}, int @var{dep_type}, rtx @var{dep_insn}, int @var{cost}) +This hook is a modified version of @samp{TARGET_SCHED_ADJUST_COST}. Instead +of passing dependence as a second parameter, it passes a type of that +dependence. This is useful to calculate cost of dependence between insns +not having the corresponding link. If @samp{TARGET_SCHED_ADJUST_COST_2} is +defined it is used instead of @samp{TARGET_SCHED_ADJUST_COST}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_H_I_D_EXTENDED (void) +This hook is called by the insn scheduler after emitting a new instruction to +the instruction stream. The hook notifies a target backend to extend its +per instruction data structures. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_SPECULATE_INSN (rtx @var{insn}, int @var{request}, rtx *@var{new_pat}) +This hook is called by the insn scheduler when @var{insn} has only +speculative dependencies and therefore can be scheduled speculatively. +The hook is used to check if the pattern of @var{insn} has a speculative +version and, in case of successful check, to generate that speculative +pattern. The hook should return 1, if the instruction has a speculative form, +or -1, if it doesn't. @var{request} describes the type of requested +speculation. If the return value equals 1 then @var{new_pat} is assigned +the generated speculative pattern. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_NEEDS_BLOCK_P (rtx @var{insn}) +This hook is called by the insn scheduler during generation of recovery code +for @var{insn}. It should return nonzero, if the corresponding check +instruction should branch to recovery code, or zero otherwise. +@end deftypefn + +@deftypefn {Target Hook} rtx TARGET_SCHED_GEN_CHECK (rtx @var{insn}, rtx @var{label}, int @var{mutate_p}) +This hook is called by the insn scheduler to generate a pattern for recovery +check instruction. If @var{mutate_p} is zero, then @var{insn} is a +speculative instruction for which the check should be generated. +@var{label} is either a label of a basic block, where recovery code should +be emitted, or a null pointer, when requested check doesn't branch to +recovery code (a simple check). If @var{mutate_p} is nonzero, then +a pattern for a branchy check corresponding to a simple check denoted by +@var{insn} should be generated. In this case @var{label} can't be null. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC (rtx @var{insn}) +This hook is used as a workaround for +@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD} not being +called on the first instruction of the ready list. The hook is used to +discard speculative instruction that stand first in the ready list from +being scheduled on the current cycle. For non-speculative instructions, +the hook should always return nonzero. For example, in the ia64 backend +the hook is used to cancel data speculative insns when the ALAT table +is nearly full. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SCHED_SET_SCHED_FLAGS (unsigned int *@var{flags}, spec_info_t @var{spec_info}) +This hook is used by the insn scheduler to find out what features should be +enabled/used. @var{flags} initially may have either the SCHED_RGN or SCHED_EBB +bit set. This denotes the scheduler pass for which the data should be +provided. The target backend should modify @var{flags} by modifying +the bits corresponding to the following features: USE_DEPS_LIST, USE_GLAT, +DETACH_LIFE_INFO, and DO_SPECULATION. For the DO_SPECULATION feature +an additional structure @var{spec_info} should be filled by the target. +The structure describes speculation types that can be used in the scheduler. +@end deftypefn + +@node Sections +@section Dividing the Output into Sections (Texts, Data, @dots{}) +@c the above section title is WAY too long. maybe cut the part between +@c the (...)? --mew 10feb93 + +An object file is divided into sections containing different types of +data. In the most common case, there are three sections: the @dfn{text +section}, which holds instructions and read-only data; the @dfn{data +section}, which holds initialized writable data; and the @dfn{bss +section}, which holds uninitialized data. Some systems have other kinds +of sections. + +@file{varasm.c} provides several well-known sections, such as +@code{text_section}, @code{data_section} and @code{bss_section}. +The normal way of controlling a @code{@var{foo}_section} variable +is to define the associated @code{@var{FOO}_SECTION_ASM_OP} macro, +as described below. The macros are only read once, when @file{varasm.c} +initializes itself, so their values must be run-time constants. +They may however depend on command-line flags. + +@emph{Note:} Some run-time files, such @file{crtstuff.c}, also make +use of the @code{@var{FOO}_SECTION_ASM_OP} macros, and expect them +to be string literals. + +Some assemblers require a different string to be written every time a +section is selected. If your assembler falls into this category, you +should define the @code{TARGET_ASM_INIT_SECTIONS} hook and use +@code{get_unnamed_section} to set up the sections. + +You must always create a @code{text_section}, either by defining +@code{TEXT_SECTION_ASM_OP} or by initializing @code{text_section} +in @code{TARGET_ASM_INIT_SECTIONS}. The same is true of +@code{data_section} and @code{DATA_SECTION_ASM_OP}. If you do not +create a distinct @code{readonly_data_section}, the default is to +reuse @code{text_section}. + +All the other @file{varasm.c} sections are optional, and are null +if the target does not provide them. + +@defmac TEXT_SECTION_ASM_OP +A C expression whose value is a string, including spacing, containing the +assembler operation that should precede instructions and read-only data. +Normally @code{"\t.text"} is right. +@end defmac + +@defmac HOT_TEXT_SECTION_NAME +If defined, a C string constant for the name of the section containing most +frequently executed functions of the program. If not defined, GCC will provide +a default definition if the target supports named sections. +@end defmac + +@defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME +If defined, a C string constant for the name of the section containing unlikely +executed functions in the program. +@end defmac + +@defmac DATA_SECTION_ASM_OP +A C expression whose value is a string, including spacing, containing the +assembler operation to identify the following data as writable initialized +data. Normally @code{"\t.data"} is right. +@end defmac + +@defmac SDATA_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +initialized, writable small data. +@end defmac + +@defmac READONLY_DATA_SECTION_ASM_OP +A C expression whose value is a string, including spacing, containing the +assembler operation to identify the following data as read-only initialized +data. +@end defmac + +@defmac BSS_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +uninitialized global data. If not defined, and neither +@code{ASM_OUTPUT_BSS} nor @code{ASM_OUTPUT_ALIGNED_BSS} are defined, +uninitialized global data will be output in the data section if +@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be +used. +@end defmac + +@defmac SBSS_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +uninitialized, writable small data. +@end defmac + +@defmac INIT_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +initialization code. If not defined, GCC will assume such a section does +not exist. This section has no corresponding @code{init_section} +variable; it is used entirely in runtime code. +@end defmac + +@defmac FINI_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +finalization code. If not defined, GCC will assume such a section does +not exist. This section has no corresponding @code{fini_section} +variable; it is used entirely in runtime code. +@end defmac + +@defmac INIT_ARRAY_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +part of the @code{.init_array} (or equivalent) section. If not +defined, GCC will assume such a section does not exist. Do not define +both this macro and @code{INIT_SECTION_ASM_OP}. +@end defmac + +@defmac FINI_ARRAY_SECTION_ASM_OP +If defined, a C expression whose value is a string, including spacing, +containing the assembler operation to identify the following data as +part of the @code{.fini_array} (or equivalent) section. If not +defined, GCC will assume such a section does not exist. Do not define +both this macro and @code{FINI_SECTION_ASM_OP}. +@end defmac + +@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function}) +If defined, an ASM statement that switches to a different section +via @var{section_op}, calls @var{function}, and switches back to +the text section. This is used in @file{crtstuff.c} if +@code{INIT_SECTION_ASM_OP} or @code{FINI_SECTION_ASM_OP} to calls +to initialization and finalization functions from the init and fini +sections. By default, this macro uses a simple function call. Some +ports need hand-crafted assembly code to avoid dependencies on +registers initialized in the function prologue or to ensure that +constant pools don't end up too far way in the text section. +@end defmac + +@defmac TARGET_LIBGCC_SDATA_SECTION +If defined, a string which names the section into which small +variables defined in crtstuff and libgcc should go. This is useful +when the target has options for optimizing access to small data, and +you want the crtstuff and libgcc routines to be conservative in what +they expect of your application yet liberal in what your application +expects. For example, for targets with a @code{.sdata} section (like +MIPS), you could compile crtstuff with @code{-G 0} so that it doesn't +require small data support from your application, but use this macro +to put small data into @code{.sdata} so that your application can +access these variables whether it uses small data or not. +@end defmac + +@defmac FORCE_CODE_SECTION_ALIGN +If defined, an ASM statement that aligns a code section to some +arbitrary boundary. This is used to force all fragments of the +@code{.init} and @code{.fini} sections to have to same alignment +and thus prevent the linker from having to add any padding. +@end defmac + +@defmac JUMP_TABLES_IN_TEXT_SECTION +Define this macro to be an expression with a nonzero value if jump +tables (for @code{tablejump} insns) should be output in the text +section, along with the assembler instructions. Otherwise, the +readonly data section is used. + +This macro is irrelevant if there is no separate readonly data section. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_INIT_SECTIONS (void) +Define this hook if you need to do something special to set up the +@file{varasm.c} sections, or if your target has some special sections +of its own that you need to create. + +GCC calls this hook after processing the command line, but before writing +any assembly code, and before calling any of the section-returning hooks +described below. +@end deftypefn + +@deftypefn {Target Hook} TARGET_ASM_RELOC_RW_MASK (void) +Return a mask describing how relocations should be treated when +selecting sections. Bit 1 should be set if global relocations +should be placed in a read-write section; bit 0 should be set if +local relocations should be placed in a read-write section. + +The default version of this function returns 3 when @option{-fpic} +is in effect, and 0 otherwise. The hook is typically redefined +when the target cannot support (some kinds of) dynamic relocations +in read-only sections even in executables. +@end deftypefn + +@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align}) +Return the section into which @var{exp} should be placed. You can +assume that @var{exp} is either a @code{VAR_DECL} node or a constant of +some sort. @var{reloc} indicates whether the initial value of @var{exp} +requires link-time relocations. Bit 0 is set when variable contains +local relocations only, while bit 1 is set for global relocations. +@var{align} is the constant alignment in bits. + +The default version of this function takes care of putting read-only +variables in @code{readonly_data_section}. + +See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}. +@end deftypefn + +@defmac USE_SELECT_SECTION_FOR_FUNCTIONS +Define this macro if you wish TARGET_ASM_SELECT_SECTION to be called +for @code{FUNCTION_DECL}s as well as for variables and constants. + +In the case of a @code{FUNCTION_DECL}, @var{reloc} will be zero if the +function has been determined to be likely to be called, and nonzero if +it is unlikely to be called. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_UNIQUE_SECTION (tree @var{decl}, int @var{reloc}) +Build up a unique section name, expressed as a @code{STRING_CST} node, +and assign it to @samp{DECL_SECTION_NAME (@var{decl})}. +As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether +the initial value of @var{exp} requires link-time relocations. + +The default version of this function appends the symbol name to the +ELF section name that would normally be used for the symbol. For +example, the function @code{foo} would be placed in @code{.text.foo}. +Whatever the actual target object format, this is often good enough. +@end deftypefn + +@deftypefn {Target Hook} {section *} TARGET_ASM_FUNCTION_RODATA_SECTION (tree @var{decl}) +Return the readonly data section associated with +@samp{DECL_SECTION_NAME (@var{decl})}. +The default version of this function selects @code{.gnu.linkonce.r.name} if +the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name} +if function is in @code{.text.name}, and the normal readonly-data section +otherwise. +@end deftypefn + +@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_RTX_SECTION (enum machine_mode @var{mode}, rtx @var{x}, unsigned HOST_WIDE_INT @var{align}) +Return the section into which a constant @var{x}, of mode @var{mode}, +should be placed. You can assume that @var{x} is some kind of +constant in RTL@. The argument @var{mode} is redundant except in the +case of a @code{const_int} rtx. @var{align} is the constant alignment +in bits. + +The default version of this function takes care of putting symbolic +constants in @code{flag_pic} mode in @code{data_section} and everything +else in @code{readonly_data_section}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ENCODE_SECTION_INFO (tree @var{decl}, rtx @var{rtl}, int @var{new_decl_p}) +Define this hook if references to a symbol or a constant must be +treated differently depending on something about the variable or +function named by the symbol (such as what section it is in). + +The hook is executed immediately after rtl has been created for +@var{decl}, which may be a variable or function declaration or +an entry in the constant pool. In either case, @var{rtl} is the +rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})} +in this hook; that field may not have been initialized yet. + +In the case of a constant, it is safe to assume that the rtl is +a @code{mem} whose address is a @code{symbol_ref}. Most decls +will also have this form, but that is not guaranteed. Global +register variables, for instance, will have a @code{reg} for their +rtl. (Normally the right thing to do with such unusual rtl is +leave it alone.) + +The @var{new_decl_p} argument will be true if this is the first time +that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will +be false for subsequent invocations, which will happen for duplicate +declarations. Whether or not anything must be done for the duplicate +declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}. +@var{new_decl_p} is always true when the hook is called for a constant. + +@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO} +The usual thing for this hook to do is to record flags in the +@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}. +Historically, the name string was modified if it was necessary to +encode more than one bit of information, but this practice is now +discouraged; use @code{SYMBOL_REF_FLAGS}. + +The default definition of this hook, @code{default_encode_section_info} +in @file{varasm.c}, sets a number of commonly-useful bits in +@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need +before overriding it. +@end deftypefn + +@deftypefn {Target Hook} const char *TARGET_STRIP_NAME_ENCODING (const char *name) +Decode @var{name} and return the real name part, sans +the characters that @code{TARGET_ENCODE_SECTION_INFO} +may have added. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_IN_SMALL_DATA_P (tree @var{exp}) +Returns true if @var{exp} should be placed into a ``small data'' section. +The default version of this hook always returns false. +@end deftypefn + +@deftypevar {Target Hook} bool TARGET_HAVE_SRODATA_SECTION +Contains the value true if the target places read-only +``small data'' into a separate section. The default value is false. +@end deftypevar + +@deftypefn {Target Hook} bool TARGET_BINDS_LOCAL_P (tree @var{exp}) +Returns true if @var{exp} names an object for which name resolution +rules must resolve to the current ``module'' (dynamic shared library +or executable image). + +The default version of this hook implements the name resolution rules +for ELF, which has a looser model of global name binding than other +currently supported object file formats. +@end deftypefn + +@deftypevar {Target Hook} bool TARGET_HAVE_TLS +Contains the value true if the target supports thread-local storage. +The default value is false. +@end deftypevar + + +@node PIC +@section Position Independent Code +@cindex position independent code +@cindex PIC + +This section describes macros that help implement generation of position +independent code. Simply defining these macros is not enough to +generate valid PIC; you must also add support to the macros +@code{GO_IF_LEGITIMATE_ADDRESS} and @code{PRINT_OPERAND_ADDRESS}, as +well as @code{LEGITIMIZE_ADDRESS}. You must modify the definition of +@samp{movsi} to do something appropriate when the source operand +contains a symbolic address. You may also need to alter the handling of +switch statements so that they use relative addresses. +@c i rearranged the order of the macros above to try to force one of +@c them to the next line, to eliminate an overfull hbox. --mew 10feb93 + +@defmac PIC_OFFSET_TABLE_REGNUM +The register number of the register used to address a table of static +data addresses in memory. In some cases this register is defined by a +processor's ``application binary interface'' (ABI)@. When this macro +is defined, RTL is generated for this register once, as with the stack +pointer and frame pointer registers. If this macro is not defined, it +is up to the machine-dependent files to allocate such a register (if +necessary). Note that this register must be fixed when in use (e.g.@: +when @code{flag_pic} is true). +@end defmac + +@defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED +Define this macro if the register defined by +@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls. Do not define +this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined. +@end defmac + +@defmac LEGITIMATE_PIC_OPERAND_P (@var{x}) +A C expression that is nonzero if @var{x} is a legitimate immediate +operand on the target machine when generating position independent code. +You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not +check this. You can also assume @var{flag_pic} is true, so you need not +check it either. You need not define this macro if all constants +(including @code{SYMBOL_REF}) can be immediate operands when generating +position independent code. +@end defmac + +@node Assembler Format +@section Defining the Output Assembler Language + +This section describes macros whose principal purpose is to describe how +to write instructions in assembler language---rather than what the +instructions do. + +@menu +* File Framework:: Structural information for the assembler file. +* Data Output:: Output of constants (numbers, strings, addresses). +* Uninitialized Data:: Output of uninitialized variables. +* Label Output:: Output and generation of labels. +* Initialization:: General principles of initialization + and termination routines. +* Macros for Initialization:: + Specific macros that control the handling of + initialization and termination routines. +* Instruction Output:: Output of actual instructions. +* Dispatch Tables:: Output of jump tables. +* Exception Region Output:: Output of exception region code. +* Alignment Output:: Pseudo ops for alignment and skipping data. +@end menu + +@node File Framework +@subsection The Overall Framework of an Assembler File +@cindex assembler format +@cindex output of assembler code + +@c prevent bad page break with this line +This describes the overall framework of an assembly file. + +@deftypefn {Target Hook} void TARGET_ASM_FILE_START () +@findex default_file_start +Output to @code{asm_out_file} any text which the assembler expects to +find at the beginning of a file. The default behavior is controlled +by two flags, documented below. Unless your target's assembler is +quite unusual, if you override the default, you should call +@code{default_file_start} at some point in your target hook. This +lets other target files rely on these variables. +@end deftypefn + +@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_APP_OFF +If this flag is true, the text of the macro @code{ASM_APP_OFF} will be +printed as the very first line in the assembly file, unless +@option{-fverbose-asm} is in effect. (If that macro has been defined +to the empty string, this variable has no effect.) With the normal +definition of @code{ASM_APP_OFF}, the effect is to notify the GNU +assembler that it need not bother stripping comments or extra +whitespace from its input. This allows it to work a bit faster. + +The default is false. You should not set it to true unless you have +verified that your port does not generate any extra whitespace or +comments that will cause GAS to issue errors in NO_APP mode. +@end deftypevr + +@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_FILE_DIRECTIVE +If this flag is true, @code{output_file_directive} will be called +for the primary source file, immediately after printing +@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect +this to be done. The default is false. +@end deftypevr + +@deftypefn {Target Hook} void TARGET_ASM_FILE_END () +Output to @code{asm_out_file} any text which the assembler expects +to find at the end of a file. The default is to output nothing. +@end deftypefn + +@deftypefun void file_end_indicate_exec_stack () +Some systems use a common convention, the @samp{.note.GNU-stack} +special section, to indicate whether or not an object file relies on +the stack being executable. If your system uses this convention, you +should define @code{TARGET_ASM_FILE_END} to this function. If you +need to do other things in that hook, have your hook function call +this function. +@end deftypefun + +@defmac ASM_COMMENT_START +A C string constant describing how to begin a comment in the target +assembler language. The compiler assumes that the comment will end at +the end of the line. +@end defmac + +@defmac ASM_APP_ON +A C string constant for text to be output before each @code{asm} +statement or group of consecutive ones. Normally this is +@code{"#APP"}, which is a comment that has no effect on most +assemblers but tells the GNU assembler that it must check the lines +that follow for all valid assembler constructs. +@end defmac + +@defmac ASM_APP_OFF +A C string constant for text to be output after each @code{asm} +statement or group of consecutive ones. Normally this is +@code{"#NO_APP"}, which tells the GNU assembler to resume making the +time-saving assumptions that are valid for ordinary compiler output. +@end defmac + +@defmac ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name}) +A C statement to output COFF information or DWARF debugging information +which indicates that filename @var{name} is the current source file to +the stdio stream @var{stream}. + +This macro need not be defined if the standard form of output +for the file format in use is appropriate. +@end defmac + +@defmac OUTPUT_QUOTED_STRING (@var{stream}, @var{string}) +A C statement to output the string @var{string} to the stdio stream +@var{stream}. If you do not call the function @code{output_quoted_string} +in your config files, GCC will only call it to output filenames to +the assembler source. So you can use it to canonicalize the format +of the filename using this macro. +@end defmac + +@defmac ASM_OUTPUT_IDENT (@var{stream}, @var{string}) +A C statement to output something to the assembler file to handle a +@samp{#ident} directive containing the text @var{string}. If this +macro is not defined, nothing is output for a @samp{#ident} directive. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags}, unsigned int @var{align}) +Output assembly directives to switch to section @var{name}. The section +should have attributes as specified by @var{flags}, which is a bit mask +of the @code{SECTION_*} flags defined in @file{output.h}. If @var{align} +is nonzero, it contains an alignment in bytes to be used for the section, +otherwise some target default should be used. Only targets that must +specify an alignment within the section directive need pay attention to +@var{align} -- we will still use @code{ASM_OUTPUT_ALIGN}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_HAVE_NAMED_SECTIONS +This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}. +@end deftypefn + +@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS} +@deftypefn {Target Hook} bool TARGET_HAVE_SWITCHABLE_BSS_SECTIONS +This flag is true if we can create zeroed data by switching to a BSS +section and then using @code{ASM_OUTPUT_SKIP} to allocate the space. +This is true on most ELF targets. +@end deftypefn + +@deftypefn {Target Hook} {unsigned int} TARGET_SECTION_TYPE_FLAGS (tree @var{decl}, const char *@var{name}, int @var{reloc}) +Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION} +based on a variable or function decl, a section name, and whether or not the +declaration's initializer may contain runtime relocations. @var{decl} may be + null, in which case read-write data should be assumed. + +The default version of this function handles choosing code vs data, +read-only vs read-write data, and @code{flag_pic}. You should only +need to override this if your target has special flags that might be +set via @code{__attribute__}. +@end deftypefn + +@need 2000 +@node Data Output +@subsection Output of Data + + +@deftypevr {Target Hook} {const char *} TARGET_ASM_BYTE_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP +@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP +These hooks specify assembly directives for creating certain kinds +of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a +byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an +aligned two-byte object, and so on. Any of the hooks may be +@code{NULL}, indicating that no suitable directive is available. + +The compiler will print these strings at the start of a new line, +followed immediately by the object's initial value. In most cases, +the string should contain a tab, a pseudo-op, and then another tab. +@end deftypevr + +@deftypefn {Target Hook} bool TARGET_ASM_INTEGER (rtx @var{x}, unsigned int @var{size}, int @var{aligned_p}) +The @code{assemble_integer} function uses this hook to output an +integer object. @var{x} is the object's value, @var{size} is its size +in bytes and @var{aligned_p} indicates whether it is aligned. The +function should return @code{true} if it was able to output the +object. If it returns false, @code{assemble_integer} will try to +split the object into smaller parts. + +The default implementation of this hook will use the +@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false} +when the relevant string is @code{NULL}. +@end deftypefn + +@defmac OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail}) +A C statement to recognize @var{rtx} patterns that +@code{output_addr_const} can't deal with, and output assembly code to +@var{stream} corresponding to the pattern @var{x}. This may be used to +allow machine-dependent @code{UNSPEC}s to appear within constants. + +If @code{OUTPUT_ADDR_CONST_EXTRA} fails to recognize a pattern, it must +@code{goto fail}, so that a standard error message is printed. If it +prints an error message itself, by calling, for example, +@code{output_operand_lossage}, it may just complete normally. +@end defmac + +@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len}) +A C statement to output to the stdio stream @var{stream} an assembler +instruction to assemble a string constant containing the @var{len} +bytes at @var{ptr}. @var{ptr} will be a C expression of type +@code{char *} and @var{len} a C expression of type @code{int}. + +If the assembler has a @code{.ascii} pseudo-op as found in the +Berkeley Unix assembler, do not define the macro +@code{ASM_OUTPUT_ASCII}. +@end defmac + +@defmac ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n}) +A C statement to output word @var{n} of a function descriptor for +@var{decl}. This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS} +is defined, and is otherwise unused. +@end defmac + +@defmac CONSTANT_POOL_BEFORE_FUNCTION +You may define this macro as a C expression. You should define the +expression to have a nonzero value if GCC should output the constant +pool for a function before the code for the function, or a zero value if +GCC should output the constant pool after the function. If you do +not define this macro, the usual case, GCC will output the constant +pool before the function. +@end defmac + +@defmac ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size}) +A C statement to output assembler commands to define the start of the +constant pool for a function. @var{funname} is a string giving +the name of the function. Should the return type of the function +be required, it can be obtained via @var{fundecl}. @var{size} +is the size, in bytes, of the constant pool that will be written +immediately after this call. + +If no constant-pool prefix is required, the usual case, this macro need +not be defined. +@end defmac + +@defmac ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto}) +A C statement (with or without semicolon) to output a constant in the +constant pool, if it needs special treatment. (This macro need not do +anything for RTL expressions that can be output normally.) + +The argument @var{file} is the standard I/O stream to output the +assembler code on. @var{x} is the RTL expression for the constant to +output, and @var{mode} is the machine mode (in case @var{x} is a +@samp{const_int}). @var{align} is the required alignment for the value +@var{x}; you should output an assembler directive to force this much +alignment. + +The argument @var{labelno} is a number to use in an internal label for +the address of this pool entry. The definition of this macro is +responsible for outputting the label definition at the proper place. +Here is how to do this: + +@smallexample +@code{(*targetm.asm_out.internal_label)} (@var{file}, "LC", @var{labelno}); +@end smallexample + +When you output a pool entry specially, you should end with a +@code{goto} to the label @var{jumpto}. This will prevent the same pool +entry from being output a second time in the usual manner. + +You need not define this macro if it would do nothing. +@end defmac + +@defmac ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size}) +A C statement to output assembler commands to at the end of the constant +pool for a function. @var{funname} is a string giving the name of the +function. Should the return type of the function be required, you can +obtain it via @var{fundecl}. @var{size} is the size, in bytes, of the +constant pool that GCC wrote immediately before this call. + +If no constant-pool epilogue is required, the usual case, you need not +define this macro. +@end defmac + +@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C}) +Define this macro as a C expression which is nonzero if @var{C} is +used as a logical line separator by the assembler. + +If you do not define this macro, the default is that only +the character @samp{;} is treated as a logical line separator. +@end defmac + +@deftypevr {Target Hook} {const char *} TARGET_ASM_OPEN_PAREN +@deftypevrx {Target Hook} {const char *} TARGET_ASM_CLOSE_PAREN +These target hooks are C string constants, describing the syntax in the +assembler for grouping arithmetic expressions. If not overridden, they +default to normal parentheses, which is correct for most assemblers. +@end deftypevr + + These macros are provided by @file{real.h} for writing the definitions +of @code{ASM_OUTPUT_DOUBLE} and the like: + +@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l}) +@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l}) +@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l}) +@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l}) +@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l}) +@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@var{x}, @var{l}) +These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the +target's floating point representation, and store its bit pattern in +the variable @var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE} and +@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a +simple @code{long int}. For the others, it should be an array of +@code{long int}. The number of elements in this array is determined +by the size of the desired target floating point data type: 32 bits of +it go in each @code{long int} array element. Each array element holds +32 bits of the result, even if @code{long int} is wider than 32 bits +on the host machine. + +The array element values are designed so that you can print them out +using @code{fprintf} in the order they should appear in the target +machine's memory. +@end defmac + +@node Uninitialized Data +@subsection Output of Uninitialized Variables + +Each of the macros in this section is used to do the whole job of +outputting a single uninitialized variable. + +@defmac ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} the assembler definition of a common-label named +@var{name} whose size is @var{size} bytes. The variable @var{rounded} +is the size rounded up to whatever alignment the caller wants. + +Use the expression @code{assemble_name (@var{stream}, @var{name})} to +output the name itself; before and after that, output the additional +assembler syntax for defining the name, and a newline. + +This macro controls how the assembler definitions of uninitialized +common global variables are output. +@end defmac + +@defmac ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment}) +Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a +separate, explicit argument. If you define this macro, it is used in +place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in +handling the required alignment of the variable. The alignment is specified +as the number of bits. +@end defmac + +@defmac ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment}) +Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the +variable to be output, if there is one, or @code{NULL_TREE} if there +is no corresponding variable. If you define this macro, GCC will use it +in place of both @code{ASM_OUTPUT_COMMON} and +@code{ASM_OUTPUT_ALIGNED_COMMON}. Define this macro when you need to see +the variable's decl in order to chose what to output. +@end defmac + +@defmac ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} the assembler definition of uninitialized global @var{decl} named +@var{name} whose size is @var{size} bytes. The variable @var{rounded} +is the size rounded up to whatever alignment the caller wants. + +Try to use function @code{asm_output_bss} defined in @file{varasm.c} when +defining this macro. If unable, use the expression +@code{assemble_name (@var{stream}, @var{name})} to output the name itself; +before and after that, output the additional assembler syntax for defining +the name, and a newline. + +There are two ways of handling global BSS. One is to define either +this macro or its aligned counterpart, @code{ASM_OUTPUT_ALIGNED_BSS}. +The other is to have @code{TARGET_ASM_SELECT_SECTION} return a +switchable BSS section (@pxref{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}). +You do not need to do both. + +Some languages do not have @code{common} data, and require a +non-common form of global BSS in order to handle uninitialized globals +efficiently. C++ is one example of this. However, if the target does +not support global BSS, the front end may choose to make globals +common in order to save space in the object file. +@end defmac + +@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment}) +Like @code{ASM_OUTPUT_BSS} except takes the required alignment as a +separate, explicit argument. If you define this macro, it is used in +place of @code{ASM_OUTPUT_BSS}, and gives you more flexibility in +handling the required alignment of the variable. The alignment is specified +as the number of bits. + +Try to use function @code{asm_output_aligned_bss} defined in file +@file{varasm.c} when defining this macro. +@end defmac + +@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} the assembler definition of a local-common-label named +@var{name} whose size is @var{size} bytes. The variable @var{rounded} +is the size rounded up to whatever alignment the caller wants. + +Use the expression @code{assemble_name (@var{stream}, @var{name})} to +output the name itself; before and after that, output the additional +assembler syntax for defining the name, and a newline. + +This macro controls how the assembler definitions of uninitialized +static variables are output. +@end defmac + +@defmac ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment}) +Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a +separate, explicit argument. If you define this macro, it is used in +place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in +handling the required alignment of the variable. The alignment is specified +as the number of bits. +@end defmac + +@defmac ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment}) +Like @code{ASM_OUTPUT_ALIGNED_DECL} except that @var{decl} of the +variable to be output, if there is one, or @code{NULL_TREE} if there +is no corresponding variable. If you define this macro, GCC will use it +in place of both @code{ASM_OUTPUT_DECL} and +@code{ASM_OUTPUT_ALIGNED_DECL}. Define this macro when you need to see +the variable's decl in order to chose what to output. +@end defmac + +@node Label Output +@subsection Output and Generation of Labels + +@c prevent bad page break with this line +This is about outputting labels. + +@findex assemble_name +@defmac ASM_OUTPUT_LABEL (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} the assembler definition of a label named @var{name}. +Use the expression @code{assemble_name (@var{stream}, @var{name})} to +output the name itself; before and after that, output the additional +assembler syntax for defining the name, and a newline. A default +definition of this macro is provided which is correct for most systems. +@end defmac + +@findex assemble_name_raw +@defmac ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{name}) +Identical to @code{ASM_OUTPUT_LABEL}, except that @var{name} is known +to refer to a compiler-generated label. The default definition uses +@code{assemble_name_raw}, which is like @code{assemble_name} except +that it is more efficient. +@end defmac + +@defmac SIZE_ASM_OP +A C string containing the appropriate assembler directive to specify the +size of a symbol, without any arguments. On systems that use ELF, the +default (in @file{config/elfos.h}) is @samp{"\t.size\t"}; on other +systems, the default is not to define this macro. + +Define this macro only if it is correct to use the default definitions +of @code{ASM_OUTPUT_SIZE_DIRECTIVE} and @code{ASM_OUTPUT_MEASURED_SIZE} +for your system. If you need your own custom definitions of those +macros, or if you do not need explicit symbol sizes at all, do not +define this macro. +@end defmac + +@defmac ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} a directive telling the assembler that the size of the +symbol @var{name} is @var{size}. @var{size} is a @code{HOST_WIDE_INT}. +If you define @code{SIZE_ASM_OP}, a default definition of this macro is +provided. +@end defmac + +@defmac ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} a directive telling the assembler to calculate the size of +the symbol @var{name} by subtracting its address from the current +address. + +If you define @code{SIZE_ASM_OP}, a default definition of this macro is +provided. The default assumes that the assembler recognizes a special +@samp{.} symbol as referring to the current address, and can calculate +the difference between this and another symbol. If your assembler does +not recognize @samp{.} or cannot do calculations with it, you will need +to redefine @code{ASM_OUTPUT_MEASURED_SIZE} to use some other technique. +@end defmac + +@defmac TYPE_ASM_OP +A C string containing the appropriate assembler directive to specify the +type of a symbol, without any arguments. On systems that use ELF, the +default (in @file{config/elfos.h}) is @samp{"\t.type\t"}; on other +systems, the default is not to define this macro. + +Define this macro only if it is correct to use the default definition of +@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own +custom definition of this macro, or if you do not need explicit symbol +types at all, do not define this macro. +@end defmac + +@defmac TYPE_OPERAND_FMT +A C string which specifies (using @code{printf} syntax) the format of +the second operand to @code{TYPE_ASM_OP}. On systems that use ELF, the +default (in @file{config/elfos.h}) is @samp{"@@%s"}; on other systems, +the default is not to define this macro. + +Define this macro only if it is correct to use the default definition of +@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own +custom definition of this macro, or if you do not need explicit symbol +types at all, do not define this macro. +@end defmac + +@defmac ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} a directive telling the assembler that the type of the +symbol @var{name} is @var{type}. @var{type} is a C string; currently, +that string is always either @samp{"function"} or @samp{"object"}, but +you should not count on this. + +If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default +definition of this macro is provided. +@end defmac + +@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for declaring the name @var{name} of a +function which is being defined. This macro is responsible for +outputting the label definition (perhaps using +@code{ASM_OUTPUT_LABEL}). The argument @var{decl} is the +@code{FUNCTION_DECL} tree node representing the function. + +If this macro is not defined, then the function name is defined in the +usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}). + +You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition +of this macro. +@end defmac + +@defmac ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for declaring the size of a function +which is being defined. The argument @var{name} is the name of the +function. The argument @var{decl} is the @code{FUNCTION_DECL} tree node +representing the function. + +If this macro is not defined, then the function size is not defined. + +You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition +of this macro. +@end defmac + +@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for declaring the name @var{name} of an +initialized variable which is being defined. This macro must output the +label definition (perhaps using @code{ASM_OUTPUT_LABEL}). The argument +@var{decl} is the @code{VAR_DECL} tree node representing the variable. + +If this macro is not defined, then the variable name is defined in the +usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}). + +You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} and/or +@code{ASM_OUTPUT_SIZE_DIRECTIVE} in the definition of this macro. +@end defmac + +@defmac ASM_DECLARE_CONSTANT_NAME (@var{stream}, @var{name}, @var{exp}, @var{size}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for declaring the name @var{name} of a +constant which is being defined. This macro is responsible for +outputting the label definition (perhaps using +@code{ASM_OUTPUT_LABEL}). The argument @var{exp} is the +value of the constant, and @var{size} is the size of the constant +in bytes. @var{name} will be an internal label. + +If this macro is not defined, then the @var{name} is defined in the +usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}). + +You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition +of this macro. +@end defmac + +@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for claiming a register @var{regno} +for a global variable @var{decl} with name @var{name}. + +If you don't define this macro, that is equivalent to defining it to do +nothing. +@end defmac + +@defmac ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend}) +A C statement (sans semicolon) to finish up declaring a variable name +once the compiler has processed its initializer fully and thus has had a +chance to determine the size of an array when controlled by an +initializer. This is used on systems where it's necessary to declare +something about the size of the object. + +If you don't define this macro, that is equivalent to defining it to do +nothing. + +You may wish to use @code{ASM_OUTPUT_SIZE_DIRECTIVE} and/or +@code{ASM_OUTPUT_MEASURED_SIZE} in the definition of this macro. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_GLOBALIZE_LABEL (FILE *@var{stream}, const char *@var{name}) +This target hook is a function to output to the stdio stream +@var{stream} some commands that will make the label @var{name} global; +that is, available for reference from other files. + +The default implementation relies on a proper definition of +@code{GLOBAL_ASM_OP}. +@end deftypefn + +@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} some commands that will make the label @var{name} weak; +that is, available for reference from other files but only used if +no other definition is available. Use the expression +@code{assemble_name (@var{stream}, @var{name})} to output the name +itself; before and after that, output the additional assembler syntax +for making that name weak, and a newline. + +If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not +support weak symbols and you should not define the @code{SUPPORTS_WEAK} +macro. +@end defmac + +@defmac ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value}) +Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and +@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function +or variable decl. If @var{value} is not @code{NULL}, this C statement +should output to the stdio stream @var{stream} assembler code which +defines (equates) the weak symbol @var{name} to have the value +@var{value}. If @var{value} is @code{NULL}, it should output commands +to make @var{name} weak. +@end defmac + +@defmac ASM_OUTPUT_WEAKREF (@var{stream}, @var{decl}, @var{name}, @var{value}) +Outputs a directive that enables @var{name} to be used to refer to +symbol @var{value} with weak-symbol semantics. @code{decl} is the +declaration of @code{name}. +@end defmac + +@defmac SUPPORTS_WEAK +A C expression which evaluates to true if the target supports weak symbols. + +If you don't define this macro, @file{defaults.h} provides a default +definition. If either @code{ASM_WEAKEN_LABEL} or @code{ASM_WEAKEN_DECL} +is defined, the default definition is @samp{1}; otherwise, it is +@samp{0}. Define this macro if you want to control weak symbol support +with a compiler flag such as @option{-melf}. +@end defmac + +@defmac MAKE_DECL_ONE_ONLY (@var{decl}) +A C statement (sans semicolon) to mark @var{decl} to be emitted as a +public symbol such that extra copies in multiple translation units will +be discarded by the linker. Define this macro if your object file +format provides support for this concept, such as the @samp{COMDAT} +section flags in the Microsoft Windows PE/COFF format, and this support +requires changes to @var{decl}, such as putting it in a separate section. +@end defmac + +@defmac SUPPORTS_ONE_ONLY +A C expression which evaluates to true if the target supports one-only +semantics. + +If you don't define this macro, @file{varasm.c} provides a default +definition. If @code{MAKE_DECL_ONE_ONLY} is defined, the default +definition is @samp{1}; otherwise, it is @samp{0}. Define this macro if +you want to control one-only symbol support with a compiler flag, or if +setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to +be emitted as one-only. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_ASSEMBLE_VISIBILITY (tree @var{decl}, const char *@var{visibility}) +This target hook is a function to output to @var{asm_out_file} some +commands that will make the symbol(s) associated with @var{decl} have +hidden, protected or internal visibility as specified by @var{visibility}. +@end deftypefn + +@defmac TARGET_WEAK_NOT_IN_ARCHIVE_TOC +A C expression that evaluates to true if the target's linker expects +that weak symbols do not appear in a static archive's table of contents. +The default is @code{0}. + +Leaving weak symbols out of an archive's table of contents means that, +if a symbol will only have a definition in one translation unit and +will have undefined references from other translation units, that +symbol should not be weak. Defining this macro to be nonzero will +thus have the effect that certain symbols that would normally be weak +(explicit template instantiations, and vtables for polymorphic classes +with noninline key methods) will instead be nonweak. + +The C++ ABI requires this macro to be zero. Define this macro for +targets where full C++ ABI compliance is impossible and where linker +restrictions require weak symbols to be left out of a static archive's +table of contents. +@end defmac + +@defmac ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} any text necessary for declaring the name of an external +symbol named @var{name} which is referenced in this compilation but +not defined. The value of @var{decl} is the tree node for the +declaration. + +This macro need not be defined if it does not need to output anything. +The GNU assembler and most Unix assemblers don't require anything. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_EXTERNAL_LIBCALL (rtx @var{symref}) +This target hook is a function to output to @var{asm_out_file} an assembler +pseudo-op to declare a library function name external. The name of the +library function is given by @var{symref}, which is a @code{symbol_ref}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_MARK_DECL_PRESERVED (tree @var{decl}) +This target hook is a function to output to @var{asm_out_file} an assembler +directive to annotate used symbol. Darwin target use .no_dead_code_strip +directive. +@end deftypefn + +@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} a reference in assembler syntax to a label named +@var{name}. This should add @samp{_} to the front of the name, if that +is customary on your operating system, as it is in most Berkeley Unix +systems. This macro is used in @code{assemble_name}. +@end defmac + +@defmac ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym}) +A C statement (sans semicolon) to output a reference to +@code{SYMBOL_REF} @var{sym}. If not defined, @code{assemble_name} +will be used to output the name of the symbol. This macro may be used +to modify the way a symbol is referenced depending on information +encoded by @code{TARGET_ENCODE_SECTION_INFO}. +@end defmac + +@defmac ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf}) +A C statement (sans semicolon) to output a reference to @var{buf}, the +result of @code{ASM_GENERATE_INTERNAL_LABEL}. If not defined, +@code{assemble_name} will be used to output the name of the symbol. +This macro is not used by @code{output_asm_label}, or the @code{%l} +specifier that calls it; the intention is that this macro should be set +when it is necessary to output a label differently when its address is +being taken. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_INTERNAL_LABEL (FILE *@var{stream}, const char *@var{prefix}, unsigned long @var{labelno}) +A function to output to the stdio stream @var{stream} a label whose +name is made from the string @var{prefix} and the number @var{labelno}. + +It is absolutely essential that these labels be distinct from the labels +used for user-level functions and variables. Otherwise, certain programs +will have name conflicts with internal labels. + +It is desirable to exclude internal labels from the symbol table of the +object file. Most assemblers have a naming convention for labels that +should be excluded; on many systems, the letter @samp{L} at the +beginning of a label has this effect. You should find out what +convention your system uses, and follow it. + +The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}. +@end deftypefn + +@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num}) +A C statement to output to the stdio stream @var{stream} a debug info +label whose name is made from the string @var{prefix} and the number +@var{num}. This is useful for VLIW targets, where debug info labels +may need to be treated differently than branch target labels. On some +systems, branch target labels must be at the beginning of instruction +bundles, but debug info labels can occur in the middle of instruction +bundles. + +If this macro is not defined, then @code{(*targetm.asm_out.internal_label)} will be +used. +@end defmac + +@defmac ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num}) +A C statement to store into the string @var{string} a label whose name +is made from the string @var{prefix} and the number @var{num}. + +This string, when output subsequently by @code{assemble_name}, should +produce the output that @code{(*targetm.asm_out.internal_label)} would produce +with the same @var{prefix} and @var{num}. + +If the string begins with @samp{*}, then @code{assemble_name} will +output the rest of the string unchanged. It is often convenient for +@code{ASM_GENERATE_INTERNAL_LABEL} to use @samp{*} in this way. If the +string doesn't start with @samp{*}, then @code{ASM_OUTPUT_LABELREF} gets +to output the string, and may change it. (Of course, +@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so +you should know what it does on your machine.) +@end defmac + +@defmac ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number}) +A C expression to assign to @var{outvar} (which is a variable of type +@code{char *}) a newly allocated string made from the string +@var{name} and the number @var{number}, with some suitable punctuation +added. Use @code{alloca} to get space for the string. + +The string will be used as an argument to @code{ASM_OUTPUT_LABELREF} to +produce an assembler label for an internal static variable whose name is +@var{name}. Therefore, the string must be such as to result in valid +assembler code. The argument @var{number} is different each time this +macro is executed; it prevents conflicts between similarly-named +internal static variables in different scopes. + +Ideally this string should not be a valid C identifier, to prevent any +conflict with the user's own symbols. Most assemblers allow periods +or percent signs in assembler symbols; putting at least one of these +between the name and the number will suffice. + +If this macro is not defined, a default definition will be provided +which is correct for most systems. +@end defmac + +@defmac ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value}) +A C statement to output to the stdio stream @var{stream} assembler code +which defines (equates) the symbol @var{name} to have the value @var{value}. + +@findex SET_ASM_OP +If @code{SET_ASM_OP} is defined, a default definition is provided which is +correct for most systems. +@end defmac + +@defmac ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value}) +A C statement to output to the stdio stream @var{stream} assembler code +which defines (equates) the symbol whose tree node is @var{decl_of_name} +to have the value of the tree node @var{decl_of_value}. This macro will +be used in preference to @samp{ASM_OUTPUT_DEF} if it is defined and if +the tree nodes are available. + +@findex SET_ASM_OP +If @code{SET_ASM_OP} is defined, a default definition is provided which is +correct for most systems. +@end defmac + +@defmac TARGET_DEFERRED_OUTPUT_DEFS (@var{decl_of_name}, @var{decl_of_value}) +A C statement that evaluates to true if the assembler code which defines +(equates) the symbol whose tree node is @var{decl_of_name} to have the value +of the tree node @var{decl_of_value} should be emitted near the end of the +current compilation unit. The default is to not defer output of defines. +This macro affects defines output by @samp{ASM_OUTPUT_DEF} and +@samp{ASM_OUTPUT_DEF_FROM_DECLS}. +@end defmac + +@defmac ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value}) +A C statement to output to the stdio stream @var{stream} assembler code +which defines (equates) the weak symbol @var{name} to have the value +@var{value}. If @var{value} is @code{NULL}, it defines @var{name} as +an undefined weak symbol. + +Define this macro if the target only supports weak aliases; define +@code{ASM_OUTPUT_DEF} instead if possible. +@end defmac + +@defmac OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name}) +Define this macro to override the default assembler names used for +Objective-C methods. + +The default name is a unique method number followed by the name of the +class (e.g.@: @samp{_1_Foo}). For methods in categories, the name of +the category is also included in the assembler name (e.g.@: +@samp{_1_Foo_Bar}). + +These names are safe on most systems, but make debugging difficult since +the method's selector is not present in the name. Therefore, particular +systems define other ways of computing names. + +@var{buf} is an expression of type @code{char *} which gives you a +buffer in which to store the name; its length is as long as +@var{class_name}, @var{cat_name} and @var{sel_name} put together, plus +50 characters extra. + +The argument @var{is_inst} specifies whether the method is an instance +method or a class method; @var{class_name} is the name of the class; +@var{cat_name} is the name of the category (or @code{NULL} if the method is not +in a category); and @var{sel_name} is the name of the selector. + +On systems where the assembler can handle quoted names, you can use this +macro to provide more human-readable names. +@end defmac + +@defmac ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} commands to declare that the label @var{name} is an +Objective-C class reference. This is only needed for targets whose +linkers have special support for NeXT-style runtimes. +@end defmac + +@defmac ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name}) +A C statement (sans semicolon) to output to the stdio stream +@var{stream} commands to declare that the label @var{name} is an +unresolved Objective-C class reference. This is only needed for targets +whose linkers have special support for NeXT-style runtimes. +@end defmac + +@node Initialization +@subsection How Initialization Functions Are Handled +@cindex initialization routines +@cindex termination routines +@cindex constructors, output of +@cindex destructors, output of + +The compiled code for certain languages includes @dfn{constructors} +(also called @dfn{initialization routines})---functions to initialize +data in the program when the program is started. These functions need +to be called before the program is ``started''---that is to say, before +@code{main} is called. + +Compiling some languages generates @dfn{destructors} (also called +@dfn{termination routines}) that should be called when the program +terminates. + +To make the initialization and termination functions work, the compiler +must output something in the assembler code to cause those functions to +be called at the appropriate time. When you port the compiler to a new +system, you need to specify how to do this. + +There are two major ways that GCC currently supports the execution of +initialization and termination functions. Each way has two variants. +Much of the structure is common to all four variations. + +@findex __CTOR_LIST__ +@findex __DTOR_LIST__ +The linker must build two lists of these functions---a list of +initialization functions, called @code{__CTOR_LIST__}, and a list of +termination functions, called @code{__DTOR_LIST__}. + +Each list always begins with an ignored function pointer (which may hold +0, @minus{}1, or a count of the function pointers after it, depending on +the environment). This is followed by a series of zero or more function +pointers to constructors (or destructors), followed by a function +pointer containing zero. + +Depending on the operating system and its executable file format, either +@file{crtstuff.c} or @file{libgcc2.c} traverses these lists at startup +time and exit time. Constructors are called in reverse order of the +list; destructors in forward order. + +The best way to handle static constructors works only for object file +formats which provide arbitrarily-named sections. A section is set +aside for a list of constructors, and another for a list of destructors. +Traditionally these are called @samp{.ctors} and @samp{.dtors}. Each +object file that defines an initialization function also puts a word in +the constructor section to point to that function. The linker +accumulates all these words into one contiguous @samp{.ctors} section. +Termination functions are handled similarly. + +This method will be chosen as the default by @file{target-def.h} if +@code{TARGET_ASM_NAMED_SECTION} is defined. A target that does not +support arbitrary sections, but does support special designated +constructor and destructor sections may define @code{CTORS_SECTION_ASM_OP} +and @code{DTORS_SECTION_ASM_OP} to achieve the same effect. + +When arbitrary sections are available, there are two variants, depending +upon how the code in @file{crtstuff.c} is called. On systems that +support a @dfn{.init} section which is executed at program startup, +parts of @file{crtstuff.c} are compiled into that section. The +program is linked by the @command{gcc} driver like this: + +@smallexample +ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o +@end smallexample + +The prologue of a function (@code{__init}) appears in the @code{.init} +section of @file{crti.o}; the epilogue appears in @file{crtn.o}. Likewise +for the function @code{__fini} in the @dfn{.fini} section. Normally these +files are provided by the operating system or by the GNU C library, but +are provided by GCC for a few targets. + +The objects @file{crtbegin.o} and @file{crtend.o} are (for most targets) +compiled from @file{crtstuff.c}. They contain, among other things, code +fragments within the @code{.init} and @code{.fini} sections that branch +to routines in the @code{.text} section. The linker will pull all parts +of a section together, which results in a complete @code{__init} function +that invokes the routines we need at startup. + +To use this variant, you must define the @code{INIT_SECTION_ASM_OP} +macro properly. + +If no init section is available, when GCC compiles any function called +@code{main} (or more accurately, any function designated as a program +entry point by the language front end calling @code{expand_main_function}), +it inserts a procedure call to @code{__main} as the first executable code +after the function prologue. The @code{__main} function is defined +in @file{libgcc2.c} and runs the global constructors. + +In file formats that don't support arbitrary sections, there are again +two variants. In the simplest variant, the GNU linker (GNU @code{ld}) +and an `a.out' format must be used. In this case, +@code{TARGET_ASM_CONSTRUCTOR} is defined to produce a @code{.stabs} +entry of type @samp{N_SETT}, referencing the name @code{__CTOR_LIST__}, +and with the address of the void function containing the initialization +code as its value. The GNU linker recognizes this as a request to add +the value to a @dfn{set}; the values are accumulated, and are eventually +placed in the executable as a vector in the format described above, with +a leading (ignored) count and a trailing zero element. +@code{TARGET_ASM_DESTRUCTOR} is handled similarly. Since no init +section is available, the absence of @code{INIT_SECTION_ASM_OP} causes +the compilation of @code{main} to call @code{__main} as above, starting +the initialization process. + +The last variant uses neither arbitrary sections nor the GNU linker. +This is preferable when you want to do dynamic linking and when using +file formats which the GNU linker does not support, such as `ECOFF'@. In +this case, @code{TARGET_HAVE_CTORS_DTORS} is false, initialization and +termination functions are recognized simply by their names. This requires +an extra program in the linkage step, called @command{collect2}. This program +pretends to be the linker, for use with GCC; it does its job by running +the ordinary linker, but also arranges to include the vectors of +initialization and termination functions. These functions are called +via @code{__main} as described above. In order to use this method, +@code{use_collect2} must be defined in the target in @file{config.gcc}. + +@ifinfo +The following section describes the specific macros that control and +customize the handling of initialization and termination functions. +@end ifinfo + +@node Macros for Initialization +@subsection Macros Controlling Initialization Routines + +Here are the macros that control how the compiler handles initialization +and termination functions: + +@defmac INIT_SECTION_ASM_OP +If defined, a C string constant, including spacing, for the assembler +operation to identify the following data as initialization code. If not +defined, GCC will assume such a section does not exist. When you are +using special sections for initialization and termination functions, this +macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to +run the initialization functions. +@end defmac + +@defmac HAS_INIT_SECTION +If defined, @code{main} will not call @code{__main} as described above. +This macro should be defined for systems that control start-up code +on a symbol-by-symbol basis, such as OSF/1, and should not +be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}. +@end defmac + +@defmac LD_INIT_SWITCH +If defined, a C string constant for a switch that tells the linker that +the following symbol is an initialization routine. +@end defmac + +@defmac LD_FINI_SWITCH +If defined, a C string constant for a switch that tells the linker that +the following symbol is a finalization routine. +@end defmac + +@defmac COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func}) +If defined, a C statement that will write a function that can be +automatically called when a shared library is loaded. The function +should call @var{func}, which takes no arguments. If not defined, and +the object format requires an explicit initialization function, then a +function called @code{_GLOBAL__DI} will be generated. + +This function and the following one are used by collect2 when linking a +shared library that needs constructors or destructors, or has DWARF2 +exception tables embedded in the code. +@end defmac + +@defmac COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func}) +If defined, a C statement that will write a function that can be +automatically called when a shared library is unloaded. The function +should call @var{func}, which takes no arguments. If not defined, and +the object format requires an explicit finalization function, then a +function called @code{_GLOBAL__DD} will be generated. +@end defmac + +@defmac INVOKE__main +If defined, @code{main} will call @code{__main} despite the presence of +@code{INIT_SECTION_ASM_OP}. This macro should be defined for systems +where the init section is not actually run automatically, but is still +useful for collecting the lists of constructors and destructors. +@end defmac + +@defmac SUPPORTS_INIT_PRIORITY +If nonzero, the C++ @code{init_priority} attribute is supported and the +compiler should emit instructions to control the order of initialization +of objects. If zero, the compiler will issue an error message upon +encountering an @code{init_priority} attribute. +@end defmac + +@deftypefn {Target Hook} bool TARGET_HAVE_CTORS_DTORS +This value is true if the target supports some ``native'' method of +collecting constructors and destructors to be run at startup and exit. +It is false if we must use @command{collect2}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_CONSTRUCTOR (rtx @var{symbol}, int @var{priority}) +If defined, a function that outputs assembler code to arrange to call +the function referenced by @var{symbol} at initialization time. + +Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking +no arguments and with no return value. If the target supports initialization +priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY}; +otherwise it must be @code{DEFAULT_INIT_PRIORITY}. + +If this macro is not defined by the target, a suitable default will +be chosen if (1) the target supports arbitrary section names, (2) the +target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2} +is not defined. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_DESTRUCTOR (rtx @var{symbol}, int @var{priority}) +This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination +functions rather than initialization functions. +@end deftypefn + +If @code{TARGET_HAVE_CTORS_DTORS} is true, the initialization routine +generated for the generated object file will have static linkage. + +If your system uses @command{collect2} as the means of processing +constructors, then that program normally uses @command{nm} to scan +an object file for constructor functions to be called. + +On certain kinds of systems, you can define this macro to make +@command{collect2} work faster (and, in some cases, make it work at all): + +@defmac OBJECT_FORMAT_COFF +Define this macro if the system uses COFF (Common Object File Format) +object files, so that @command{collect2} can assume this format and scan +object files directly for dynamic constructor/destructor functions. + +This macro is effective only in a native compiler; @command{collect2} as +part of a cross compiler always uses @command{nm} for the target machine. +@end defmac + +@defmac REAL_NM_FILE_NAME +Define this macro as a C string constant containing the file name to use +to execute @command{nm}. The default is to search the path normally for +@command{nm}. + +If your system supports shared libraries and has a program to list the +dynamic dependencies of a given library or executable, you can define +these macros to enable support for running initialization and +termination functions in shared libraries: +@end defmac + +@defmac LDD_SUFFIX +Define this macro to a C string constant containing the name of the program +which lists dynamic dependencies, like @command{"ldd"} under SunOS 4. +@end defmac + +@defmac PARSE_LDD_OUTPUT (@var{ptr}) +Define this macro to be C code that extracts filenames from the output +of the program denoted by @code{LDD_SUFFIX}. @var{ptr} is a variable +of type @code{char *} that points to the beginning of a line of output +from @code{LDD_SUFFIX}. If the line lists a dynamic dependency, the +code must advance @var{ptr} to the beginning of the filename on that +line. Otherwise, it must set @var{ptr} to @code{NULL}. +@end defmac + +@node Instruction Output +@subsection Output of Assembler Instructions + +@c prevent bad page break with this line +This describes assembler instruction output. + +@defmac REGISTER_NAMES +A C initializer containing the assembler's names for the machine +registers, each one as a C string constant. This is what translates +register numbers in the compiler into assembler language. +@end defmac + +@defmac ADDITIONAL_REGISTER_NAMES +If defined, a C initializer for an array of structures containing a name +and a register number. This macro defines additional names for hard +registers, thus allowing the @code{asm} option in declarations to refer +to registers using alternate names. +@end defmac + +@defmac ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr}) +Define this macro if you are using an unusual assembler that +requires different names for the machine instructions. + +The definition is a C statement or statements which output an +assembler instruction opcode to the stdio stream @var{stream}. The +macro-operand @var{ptr} is a variable of type @code{char *} which +points to the opcode name in its ``internal'' form---the form that is +written in the machine description. The definition should output the +opcode name to @var{stream}, performing any translation you desire, and +increment the variable @var{ptr} to point at the end of the opcode +so that it will not be output twice. + +In fact, your macro definition may process less than the entire opcode +name, or more than the opcode name; but if you want to process text +that includes @samp{%}-sequences to substitute operands, you must take +care of the substitution yourself. Just be sure to increment +@var{ptr} over whatever text should not be output normally. + +@findex recog_data.operand +If you need to look at the operand values, they can be found as the +elements of @code{recog_data.operand}. + +If the macro definition does nothing, the instruction is output +in the usual way. +@end defmac + +@defmac FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands}) +If defined, a C statement to be executed just prior to the output of +assembler code for @var{insn}, to modify the extracted operands so +they will be output differently. + +Here the argument @var{opvec} is the vector containing the operands +extracted from @var{insn}, and @var{noperands} is the number of +elements of the vector which contain meaningful data for this insn. +The contents of this vector are what will be used to convert the insn +template into assembler code, so you can change the assembler output +by changing the contents of the vector. + +This macro is useful when various assembler syntaxes share a single +file of instruction patterns; by defining this macro differently, you +can cause a large class of instructions to be output differently (such +as with rearranged operands). Naturally, variations in assembler +syntax affecting individual insn patterns ought to be handled by +writing conditional output routines in those patterns. + +If this macro is not defined, it is equivalent to a null statement. +@end defmac + +@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code}) +A C compound statement to output to stdio stream @var{stream} the +assembler syntax for an instruction operand @var{x}. @var{x} is an +RTL expression. + +@var{code} is a value that can be used to specify one of several ways +of printing the operand. It is used when identical operands must be +printed differently depending on the context. @var{code} comes from +the @samp{%} specification that was used to request printing of the +operand. If the specification was just @samp{%@var{digit}} then +@var{code} is 0; if the specification was @samp{%@var{ltr} +@var{digit}} then @var{code} is the ASCII code for @var{ltr}. + +@findex reg_names +If @var{x} is a register, this macro should print the register's name. +The names can be found in an array @code{reg_names} whose type is +@code{char *[]}. @code{reg_names} is initialized from +@code{REGISTER_NAMES}. + +When the machine description has a specification @samp{%@var{punct}} +(a @samp{%} followed by a punctuation character), this macro is called +with a null pointer for @var{x} and the punctuation character for +@var{code}. +@end defmac + +@defmac PRINT_OPERAND_PUNCT_VALID_P (@var{code}) +A C expression which evaluates to true if @var{code} is a valid +punctuation character for use in the @code{PRINT_OPERAND} macro. If +@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no +punctuation characters (except for the standard one, @samp{%}) are used +in this way. +@end defmac + +@defmac PRINT_OPERAND_ADDRESS (@var{stream}, @var{x}) +A C compound statement to output to stdio stream @var{stream} the +assembler syntax for an instruction operand that is a memory reference +whose address is @var{x}. @var{x} is an RTL expression. + +@cindex @code{TARGET_ENCODE_SECTION_INFO} usage +On some machines, the syntax for a symbolic address depends on the +section that the address refers to. On these machines, define the hook +@code{TARGET_ENCODE_SECTION_INFO} to store the information into the +@code{symbol_ref}, and then check for it here. @xref{Assembler +Format}. +@end defmac + +@findex dbr_sequence_length +@defmac DBR_OUTPUT_SEQEND (@var{file}) +A C statement, to be executed after all slot-filler instructions have +been output. If necessary, call @code{dbr_sequence_length} to +determine the number of slots filled in a sequence (zero if not +currently outputting a sequence), to decide how many no-ops to output, +or whatever. + +Don't define this macro if it has nothing to do, but it is helpful in +reading assembly output if the extent of the delay sequence is made +explicit (e.g.@: with white space). +@end defmac + +@findex final_sequence +Note that output routines for instructions with delay slots must be +prepared to deal with not being output as part of a sequence +(i.e.@: when the scheduling pass is not run, or when no slot fillers could be +found.) The variable @code{final_sequence} is null when not +processing a sequence, otherwise it contains the @code{sequence} rtx +being output. + +@findex asm_fprintf +@defmac REGISTER_PREFIX +@defmacx LOCAL_LABEL_PREFIX +@defmacx USER_LABEL_PREFIX +@defmacx IMMEDIATE_PREFIX +If defined, C string expressions to be used for the @samp{%R}, @samp{%L}, +@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see +@file{final.c}). These are useful when a single @file{md} file must +support multiple assembler formats. In that case, the various @file{tm.h} +files can define these macros differently. +@end defmac + +@defmac ASM_FPRINTF_EXTENSIONS (@var{file}, @var{argptr}, @var{format}) +If defined this macro should expand to a series of @code{case} +statements which will be parsed inside the @code{switch} statement of +the @code{asm_fprintf} function. This allows targets to define extra +printf formats which may useful when generating their assembler +statements. Note that uppercase letters are reserved for future +generic extensions to asm_fprintf, and so are not available to target +specific code. The output file is given by the parameter @var{file}. +The varargs input pointer is @var{argptr} and the rest of the format +string, starting the character after the one that is being switched +upon, is pointed to by @var{format}. +@end defmac + +@defmac ASSEMBLER_DIALECT +If your target supports multiple dialects of assembler language (such as +different opcodes), define this macro as a C expression that gives the +numeric index of the assembler language dialect to use, with zero as the +first variant. + +If this macro is defined, you may use constructs of the form +@smallexample +@samp{@{option0|option1|option2@dots{}@}} +@end smallexample +@noindent +in the output templates of patterns (@pxref{Output Template}) or in the +first argument of @code{asm_fprintf}. This construct outputs +@samp{option0}, @samp{option1}, @samp{option2}, etc., if the value of +@code{ASSEMBLER_DIALECT} is zero, one, two, etc. Any special characters +within these strings retain their usual meaning. If there are fewer +alternatives within the braces than the value of +@code{ASSEMBLER_DIALECT}, the construct outputs nothing. + +If you do not define this macro, the characters @samp{@{}, @samp{|} and +@samp{@}} do not have any special meaning when used in templates or +operands to @code{asm_fprintf}. + +Define the macros @code{REGISTER_PREFIX}, @code{LOCAL_LABEL_PREFIX}, +@code{USER_LABEL_PREFIX} and @code{IMMEDIATE_PREFIX} if you can express +the variations in assembler language syntax with that mechanism. Define +@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax +if the syntax variant are larger and involve such things as different +opcodes or operand order. +@end defmac + +@defmac ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno}) +A C expression to output to @var{stream} some assembler code +which will push hard register number @var{regno} onto the stack. +The code need not be optimal, since this macro is used only when +profiling. +@end defmac + +@defmac ASM_OUTPUT_REG_POP (@var{stream}, @var{regno}) +A C expression to output to @var{stream} some assembler code +which will pop hard register number @var{regno} off of the stack. +The code need not be optimal, since this macro is used only when +profiling. +@end defmac + +@node Dispatch Tables +@subsection Output of Dispatch Tables + +@c prevent bad page break with this line +This concerns dispatch tables. + +@cindex dispatch table +@defmac ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel}) +A C statement to output to the stdio stream @var{stream} an assembler +pseudo-instruction to generate a difference between two labels. +@var{value} and @var{rel} are the numbers of two internal labels. The +definitions of these labels are output using +@code{(*targetm.asm_out.internal_label)}, and they must be printed in the same +way here. For example, + +@smallexample +fprintf (@var{stream}, "\t.word L%d-L%d\n", + @var{value}, @var{rel}) +@end smallexample + +You must provide this macro on machines where the addresses in a +dispatch table are relative to the table's own address. If defined, GCC +will also use this macro on all machines when producing PIC@. +@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the +mode and flags can be read. +@end defmac + +@defmac ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value}) +This macro should be provided on machines where the addresses +in a dispatch table are absolute. + +The definition should be a C statement to output to the stdio stream +@var{stream} an assembler pseudo-instruction to generate a reference to +a label. @var{value} is the number of an internal label whose +definition is output using @code{(*targetm.asm_out.internal_label)}. +For example, + +@smallexample +fprintf (@var{stream}, "\t.word L%d\n", @var{value}) +@end smallexample +@end defmac + +@defmac ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table}) +Define this if the label before a jump-table needs to be output +specially. The first three arguments are the same as for +@code{(*targetm.asm_out.internal_label)}; the fourth argument is the +jump-table which follows (a @code{jump_insn} containing an +@code{addr_vec} or @code{addr_diff_vec}). + +This feature is used on system V to output a @code{swbeg} statement +for the table. + +If this macro is not defined, these labels are output with +@code{(*targetm.asm_out.internal_label)}. +@end defmac + +@defmac ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table}) +Define this if something special must be output at the end of a +jump-table. The definition should be a C statement to be executed +after the assembler code for the table is written. It should write +the appropriate code to stdio stream @var{stream}. The argument +@var{table} is the jump-table insn, and @var{num} is the label-number +of the preceding label. + +If this macro is not defined, nothing special is output at the end of +the jump-table. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_EMIT_UNWIND_LABEL (@var{stream}, @var{decl}, @var{for_eh}, @var{empty}) +This target hook emits a label at the beginning of each FDE@. It +should be defined on targets where FDEs need special labels, and it +should write the appropriate label, for the FDE associated with the +function declaration @var{decl}, to the stdio stream @var{stream}. +The third argument, @var{for_eh}, is a boolean: true if this is for an +exception table. The fourth argument, @var{empty}, is a boolean: +true if this is a placeholder label for an omitted FDE@. + +The default is that FDEs are not given nonlocal labels. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (@var{stream}) +This target hook emits a label at the beginning of the exception table. +It should be defined on targets where it is desirable for the table +to be broken up according to function. + +The default is that no label is emitted. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn}) +This target hook emits and assembly directives required to unwind the +given instruction. This is only used when TARGET_UNWIND_INFO is set. +@end deftypefn + +@node Exception Region Output +@subsection Assembler Commands for Exception Regions + +@c prevent bad page break with this line + +This describes commands marking the start and the end of an exception +region. + +@defmac EH_FRAME_SECTION_NAME +If defined, a C string constant for the name of the section containing +exception handling frame unwind information. If not defined, GCC will +provide a default definition if the target supports named sections. +@file{crtstuff.c} uses this macro to switch to the appropriate section. + +You should define this symbol if your target supports DWARF 2 frame +unwind information and the default definition does not work. +@end defmac + +@defmac EH_FRAME_IN_DATA_SECTION +If defined, DWARF 2 frame unwind information will be placed in the +data section even though the target supports named sections. This +might be necessary, for instance, if the system linker does garbage +collection and sections cannot be marked as not to be collected. + +Do not define this macro unless @code{TARGET_ASM_NAMED_SECTION} is +also defined. +@end defmac + +@defmac EH_TABLES_CAN_BE_READ_ONLY +Define this macro to 1 if your target is such that no frame unwind +information encoding used with non-PIC code will ever require a +runtime relocation, but the linker may not support merging read-only +and read-write sections into a single read-write section. +@end defmac + +@defmac MASK_RETURN_ADDR +An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so +that it does not contain any extraneous set bits in it. +@end defmac + +@defmac DWARF2_UNWIND_INFO +Define this macro to 0 if your target supports DWARF 2 frame unwind +information, but it does not yet work with exception handling. +Otherwise, if your target supports this information (if it defines +@samp{INCOMING_RETURN_ADDR_RTX} and either @samp{UNALIGNED_INT_ASM_OP} +or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of 1. + +If @code{TARGET_UNWIND_INFO} is defined, the target specific unwinder +will be used in all cases. Defining this macro will enable the generation +of DWARF 2 frame debugging information. + +If @code{TARGET_UNWIND_INFO} is not defined, and this macro is defined to 1, +the DWARF 2 unwinder will be the default exception handling mechanism; +otherwise, the @code{setjmp}/@code{longjmp}-based scheme will be used by +default. +@end defmac + +@defmac TARGET_UNWIND_INFO +Define this macro if your target has ABI specified unwind tables. Usually +these will be output by @code{TARGET_UNWIND_EMIT}. +@end defmac + +@deftypevar {Target Hook} bool TARGET_UNWIND_TABLES_DEFAULT +This variable should be set to @code{true} if the target ABI requires unwinding +tables even when exceptions are not used. +@end deftypevar + +@defmac MUST_USE_SJLJ_EXCEPTIONS +This macro need only be defined if @code{DWARF2_UNWIND_INFO} is +runtime-variable. In that case, @file{except.h} cannot correctly +determine the corresponding definition of @code{MUST_USE_SJLJ_EXCEPTIONS}, +so the target must provide it directly. +@end defmac + +@defmac DONT_USE_BUILTIN_SETJMP +Define this macro to 1 if the @code{setjmp}/@code{longjmp}-based scheme +should use the @code{setjmp}/@code{longjmp} functions from the C library +instead of the @code{__builtin_setjmp}/@code{__builtin_longjmp} machinery. +@end defmac + +@defmac DWARF_CIE_DATA_ALIGNMENT +This macro need only be defined if the target might save registers in the +function prologue at an offset to the stack pointer that is not aligned to +@code{UNITS_PER_WORD}. The definition should be the negative minimum +alignment if @code{STACK_GROWS_DOWNWARD} is defined, and the positive +minimum alignment otherwise. @xref{SDB and DWARF}. Only applicable if +the target supports DWARF 2 frame unwind information. +@end defmac + +@deftypevar {Target Hook} bool TARGET_TERMINATE_DW2_EH_FRAME_INFO +Contains the value true if the target should add a zero word onto the +end of a Dwarf-2 frame info section when used for exception handling. +Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and +true otherwise. +@end deftypevar + +@deftypefn {Target Hook} rtx TARGET_DWARF_REGISTER_SPAN (rtx @var{reg}) +Given a register, this hook should return a parallel of registers to +represent where to find the register pieces. Define this hook if the +register and its mode are represented in Dwarf in non-contiguous +locations, or if the register should be represented in more than one +register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}. +If not defined, the default is to return @code{NULL_RTX}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_ASM_TTYPE (rtx @var{sym}) +This hook is used to output a reference from a frame unwinding table to +the type_info object identified by @var{sym}. It should return @code{true} +if the reference was output. Returning @code{false} will cause the +reference to be output using the normal Dwarf2 routines. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_ARM_EABI_UNWINDER +This hook should be set to @code{true} on targets that use an ARM EABI +based unwinding library, and @code{false} on other targets. This effects +the format of unwinding tables, and how the unwinder in entered after +running a cleanup. The default is @code{false}. +@end deftypefn + +@node Alignment Output +@subsection Assembler Commands for Alignment + +@c prevent bad page break with this line +This describes commands for alignment. + +@defmac JUMP_ALIGN (@var{label}) +The alignment (log base 2) to put in front of @var{label}, which is +a common destination of jumps and has no fallthru incoming edge. + +This macro need not be defined if you don't want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. + +Unless it's necessary to inspect the @var{label} parameter, it is better +to set the variable @var{align_jumps} in the target's +@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's +selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation. +@end defmac + +@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label}) +The alignment (log base 2) to put in front of @var{label}, which follows +a @code{BARRIER}. + +This macro need not be defined if you don't want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. +@end defmac + +@defmac LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP +The maximum number of bytes to skip when applying +@code{LABEL_ALIGN_AFTER_BARRIER}. This works only if +@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined. +@end defmac + +@defmac LOOP_ALIGN (@var{label}) +The alignment (log base 2) to put in front of @var{label}, which follows +a @code{NOTE_INSN_LOOP_BEG} note. + +This macro need not be defined if you don't want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. + +Unless it's necessary to inspect the @var{label} parameter, it is better +to set the variable @code{align_loops} in the target's +@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's +selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation. +@end defmac + +@defmac LOOP_ALIGN_MAX_SKIP +The maximum number of bytes to skip when applying @code{LOOP_ALIGN}. +This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined. +@end defmac + +@defmac LABEL_ALIGN (@var{label}) +The alignment (log base 2) to put in front of @var{label}. +If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment, +the maximum of the specified values is used. + +Unless it's necessary to inspect the @var{label} parameter, it is better +to set the variable @code{align_labels} in the target's +@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's +selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation. +@end defmac + +@defmac LABEL_ALIGN_MAX_SKIP +The maximum number of bytes to skip when applying @code{LABEL_ALIGN}. +This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined. +@end defmac + +@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes}) +A C statement to output to the stdio stream @var{stream} an assembler +instruction to advance the location counter by @var{nbytes} bytes. +Those bytes should be zero when loaded. @var{nbytes} will be a C +expression of type @code{int}. +@end defmac + +@defmac ASM_NO_SKIP_IN_TEXT +Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the +text section because it fails to put zeros in the bytes that are skipped. +This is true on many Unix systems, where the pseudo--op to skip bytes +produces no-op instructions rather than zeros when used in the text +section. +@end defmac + +@defmac ASM_OUTPUT_ALIGN (@var{stream}, @var{power}) +A C statement to output to the stdio stream @var{stream} an assembler +command to advance the location counter to a multiple of 2 to the +@var{power} bytes. @var{power} will be a C expression of type @code{int}. +@end defmac + +@defmac ASM_OUTPUT_ALIGN_WITH_NOP (@var{stream}, @var{power}) +Like @code{ASM_OUTPUT_ALIGN}, except that the ``nop'' instruction is used +for padding, if necessary. +@end defmac + +@defmac ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip}) +A C statement to output to the stdio stream @var{stream} an assembler +command to advance the location counter to a multiple of 2 to the +@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to +satisfy the alignment request. @var{power} and @var{max_skip} will be +a C expression of type @code{int}. +@end defmac + +@need 3000 +@node Debugging Info +@section Controlling Debugging Information Format + +@c prevent bad page break with this line +This describes how to specify debugging information. + +@menu +* All Debuggers:: Macros that affect all debugging formats uniformly. +* DBX Options:: Macros enabling specific options in DBX format. +* DBX Hooks:: Hook macros for varying DBX format. +* File Names and DBX:: Macros controlling output of file names in DBX format. +* SDB and DWARF:: Macros for SDB (COFF) and DWARF formats. +* VMS Debug:: Macros for VMS debug format. +@end menu + +@node All Debuggers +@subsection Macros Affecting All Debugging Formats + +@c prevent bad page break with this line +These macros affect all debugging formats. + +@defmac DBX_REGISTER_NUMBER (@var{regno}) +A C expression that returns the DBX register number for the compiler +register number @var{regno}. In the default macro provided, the value +of this expression will be @var{regno} itself. But sometimes there are +some registers that the compiler knows about and DBX does not, or vice +versa. In such cases, some register may need to have one number in the +compiler and another for DBX@. + +If two registers have consecutive numbers inside GCC, and they can be +used as a pair to hold a multiword value, then they @emph{must} have +consecutive numbers after renumbering with @code{DBX_REGISTER_NUMBER}. +Otherwise, debuggers will be unable to access such a pair, because they +expect register pairs to be consecutive in their own numbering scheme. + +If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that +does not preserve register pairs, then what you must do instead is +redefine the actual register numbering scheme. +@end defmac + +@defmac DEBUGGER_AUTO_OFFSET (@var{x}) +A C expression that returns the integer offset value for an automatic +variable having address @var{x} (an RTL expression). The default +computation assumes that @var{x} is based on the frame-pointer and +gives the offset from the frame-pointer. This is required for targets +that produce debugging output for DBX or COFF-style debugging output +for SDB and allow the frame-pointer to be eliminated when the +@option{-g} options is used. +@end defmac + +@defmac DEBUGGER_ARG_OFFSET (@var{offset}, @var{x}) +A C expression that returns the integer offset value for an argument +having address @var{x} (an RTL expression). The nominal offset is +@var{offset}. +@end defmac + +@defmac PREFERRED_DEBUGGING_TYPE +A C expression that returns the type of debugging output GCC should +produce when the user specifies just @option{-g}. Define +this if you have arranged for GCC to support more than one format of +debugging output. Currently, the allowable values are @code{DBX_DEBUG}, +@code{SDB_DEBUG}, @code{DWARF_DEBUG}, @code{DWARF2_DEBUG}, +@code{XCOFF_DEBUG}, @code{VMS_DEBUG}, and @code{VMS_AND_DWARF2_DEBUG}. + +When the user specifies @option{-ggdb}, GCC normally also uses the +value of this macro to select the debugging output format, but with two +exceptions. If @code{DWARF2_DEBUGGING_INFO} is defined, GCC uses the +value @code{DWARF2_DEBUG}. Otherwise, if @code{DBX_DEBUGGING_INFO} is +defined, GCC uses @code{DBX_DEBUG}. + +The value of this macro only affects the default debugging output; the +user can always get a specific type of output by using @option{-gstabs}, +@option{-gcoff}, @option{-gdwarf-2}, @option{-gxcoff}, or @option{-gvms}. +@end defmac + +@node DBX Options +@subsection Specific Options for DBX Output + +@c prevent bad page break with this line +These are specific options for DBX output. + +@defmac DBX_DEBUGGING_INFO +Define this macro if GCC should produce debugging output for DBX +in response to the @option{-g} option. +@end defmac + +@defmac XCOFF_DEBUGGING_INFO +Define this macro if GCC should produce XCOFF format debugging output +in response to the @option{-g} option. This is a variant of DBX format. +@end defmac + +@defmac DEFAULT_GDB_EXTENSIONS +Define this macro to control whether GCC should by default generate +GDB's extended version of DBX debugging information (assuming DBX-format +debugging information is enabled at all). If you don't define the +macro, the default is 1: always generate the extended information +if there is any occasion to. +@end defmac + +@defmac DEBUG_SYMS_TEXT +Define this macro if all @code{.stabs} commands should be output while +in the text section. +@end defmac + +@defmac ASM_STABS_OP +A C string constant, including spacing, naming the assembler pseudo op to +use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol. +If you don't define this macro, @code{"\t.stabs\t"} is used. This macro +applies only to DBX debugging information format. +@end defmac + +@defmac ASM_STABD_OP +A C string constant, including spacing, naming the assembler pseudo op to +use instead of @code{"\t.stabd\t"} to define a debugging symbol whose +value is the current location. If you don't define this macro, +@code{"\t.stabd\t"} is used. This macro applies only to DBX debugging +information format. +@end defmac + +@defmac ASM_STABN_OP +A C string constant, including spacing, naming the assembler pseudo op to +use instead of @code{"\t.stabn\t"} to define a debugging symbol with no +name. If you don't define this macro, @code{"\t.stabn\t"} is used. This +macro applies only to DBX debugging information format. +@end defmac + +@defmac DBX_NO_XREFS +Define this macro if DBX on your system does not support the construct +@samp{xs@var{tagname}}. On some systems, this construct is used to +describe a forward reference to a structure named @var{tagname}. +On other systems, this construct is not supported at all. +@end defmac + +@defmac DBX_CONTIN_LENGTH +A symbol name in DBX-format debugging information is normally +continued (split into two separate @code{.stabs} directives) when it +exceeds a certain length (by default, 80 characters). On some +operating systems, DBX requires this splitting; on others, splitting +must not be done. You can inhibit splitting by defining this macro +with the value zero. You can override the default splitting-length by +defining this macro as an expression for the length you desire. +@end defmac + +@defmac DBX_CONTIN_CHAR +Normally continuation is indicated by adding a @samp{\} character to +the end of a @code{.stabs} string when a continuation follows. To use +a different character instead, define this macro as a character +constant for the character you want to use. Do not define this macro +if backslash is correct for your system. +@end defmac + +@defmac DBX_STATIC_STAB_DATA_SECTION +Define this macro if it is necessary to go to the data section before +outputting the @samp{.stabs} pseudo-op for a non-global static +variable. +@end defmac + +@defmac DBX_TYPE_DECL_STABS_CODE +The value to use in the ``code'' field of the @code{.stabs} directive +for a typedef. The default is @code{N_LSYM}. +@end defmac + +@defmac DBX_STATIC_CONST_VAR_CODE +The value to use in the ``code'' field of the @code{.stabs} directive +for a static variable located in the text section. DBX format does not +provide any ``right'' way to do this. The default is @code{N_FUN}. +@end defmac + +@defmac DBX_REGPARM_STABS_CODE +The value to use in the ``code'' field of the @code{.stabs} directive +for a parameter passed in registers. DBX format does not provide any +``right'' way to do this. The default is @code{N_RSYM}. +@end defmac + +@defmac DBX_REGPARM_STABS_LETTER +The letter to use in DBX symbol data to identify a symbol as a parameter +passed in registers. DBX format does not customarily provide any way to +do this. The default is @code{'P'}. +@end defmac + +@defmac DBX_FUNCTION_FIRST +Define this macro if the DBX information for a function and its +arguments should precede the assembler code for the function. Normally, +in DBX format, the debugging information entirely follows the assembler +code. +@end defmac + +@defmac DBX_BLOCKS_FUNCTION_RELATIVE +Define this macro, with value 1, if the value of a symbol describing +the scope of a block (@code{N_LBRAC} or @code{N_RBRAC}) should be +relative to the start of the enclosing function. Normally, GCC uses +an absolute address. +@end defmac + +@defmac DBX_LINES_FUNCTION_RELATIVE +Define this macro, with value 1, if the value of a symbol indicating +the current line number (@code{N_SLINE}) should be relative to the +start of the enclosing function. Normally, GCC uses an absolute address. +@end defmac + +@defmac DBX_USE_BINCL +Define this macro if GCC should generate @code{N_BINCL} and +@code{N_EINCL} stabs for included header files, as on Sun systems. This +macro also directs GCC to output a type number as a pair of a file +number and a type number within the file. Normally, GCC does not +generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single +number for a type number. +@end defmac + +@node DBX Hooks +@subsection Open-Ended Hooks for DBX Format + +@c prevent bad page break with this line +These are hooks for DBX format. + +@defmac DBX_OUTPUT_LBRAC (@var{stream}, @var{name}) +Define this macro to say how to output to @var{stream} the debugging +information for the start of a scope level for variable names. The +argument @var{name} is the name of an assembler symbol (for use with +@code{assemble_name}) whose value is the address where the scope begins. +@end defmac + +@defmac DBX_OUTPUT_RBRAC (@var{stream}, @var{name}) +Like @code{DBX_OUTPUT_LBRAC}, but for the end of a scope level. +@end defmac + +@defmac DBX_OUTPUT_NFUN (@var{stream}, @var{lscope_label}, @var{decl}) +Define this macro if the target machine requires special handling to +output an @code{N_FUN} entry for the function @var{decl}. +@end defmac + +@defmac DBX_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}, @var{counter}) +A C statement to output DBX debugging information before code for line +number @var{line} of the current source file to the stdio stream +@var{stream}. @var{counter} is the number of time the macro was +invoked, including the current invocation; it is intended to generate +unique labels in the assembly output. + +This macro should not be defined if the default output is correct, or +if it can be made correct by defining @code{DBX_LINES_FUNCTION_RELATIVE}. +@end defmac + +@defmac NO_DBX_FUNCTION_END +Some stabs encapsulation formats (in particular ECOFF), cannot handle the +@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct. +On those machines, define this macro to turn this feature off without +disturbing the rest of the gdb extensions. +@end defmac + +@defmac NO_DBX_BNSYM_ENSYM +Some assemblers cannot handle the @code{.stabd BNSYM/ENSYM,0,0} gdb dbx +extension construct. On those machines, define this macro to turn this +feature off without disturbing the rest of the gdb extensions. +@end defmac + +@node File Names and DBX +@subsection File Names in DBX Format + +@c prevent bad page break with this line +This describes file names in DBX format. + +@defmac DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name}) +A C statement to output DBX debugging information to the stdio stream +@var{stream}, which indicates that file @var{name} is the main source +file---the file specified as the input file for compilation. +This macro is called only once, at the beginning of compilation. + +This macro need not be defined if the standard form of output +for DBX debugging information is appropriate. + +It may be necessary to refer to a label equal to the beginning of the +text section. You can use @samp{assemble_name (stream, ltext_label_name)} +to do so. If you do this, you must also set the variable +@var{used_ltext_label_name} to @code{true}. +@end defmac + +@defmac NO_DBX_MAIN_SOURCE_DIRECTORY +Define this macro, with value 1, if GCC should not emit an indication +of the current directory for compilation and current source language at +the beginning of the file. +@end defmac + +@defmac NO_DBX_GCC_MARKER +Define this macro, with value 1, if GCC should not emit an indication +that this object file was compiled by GCC@. The default is to emit +an @code{N_OPT} stab at the beginning of every source file, with +@samp{gcc2_compiled.} for the string and value 0. +@end defmac + +@defmac DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name}) +A C statement to output DBX debugging information at the end of +compilation of the main source file @var{name}. Output should be +written to the stdio stream @var{stream}. + +If you don't define this macro, nothing special is output at the end +of compilation, which is correct for most machines. +@end defmac + +@defmac DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END +Define this macro @emph{instead of} defining +@code{DBX_OUTPUT_MAIN_SOURCE_FILE_END}, if what needs to be output at +the end of compilation is a @code{N_SO} stab with an empty string, +whose value is the highest absolute text address in the file. +@end defmac + +@need 2000 +@node SDB and DWARF +@subsection Macros for SDB and DWARF Output + +@c prevent bad page break with this line +Here are macros for SDB and DWARF output. + +@defmac SDB_DEBUGGING_INFO +Define this macro if GCC should produce COFF-style debugging output +for SDB in response to the @option{-g} option. +@end defmac + +@defmac DWARF2_DEBUGGING_INFO +Define this macro if GCC should produce dwarf version 2 format +debugging output in response to the @option{-g} option. + +@deftypefn {Target Hook} int TARGET_DWARF_CALLING_CONVENTION (tree @var{function}) +Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to +be emitted for each function. Instead of an integer return the enum +value for the @code{DW_CC_} tag. +@end deftypefn + +To support optional call frame debugging information, you must also +define @code{INCOMING_RETURN_ADDR_RTX} and either set +@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the +prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save} +as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't. +@end defmac + +@defmac DWARF2_FRAME_INFO +Define this macro to a nonzero value if GCC should always output +Dwarf 2 frame information. If @code{DWARF2_UNWIND_INFO} +(@pxref{Exception Region Output} is nonzero, GCC will output this +information not matter how you define @code{DWARF2_FRAME_INFO}. +@end defmac + +@defmac DWARF2_ASM_LINE_DEBUG_INFO +Define this macro to be a nonzero value if the assembler can generate Dwarf 2 +line debug info sections. This will result in much more compact line number +tables, and hence is desirable if it works. +@end defmac + +@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2}) +A C statement to issue assembly directives that create a difference +@var{lab1} minus @var{lab2}, using an integer of the given @var{size}. +@end defmac + +@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label}, @var{section}) +A C statement to issue assembly directives that create a +section-relative reference to the given @var{label}, using an integer of the +given @var{size}. The label is known to be defined in the given @var{section}. +@end defmac + +@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label}) +A C statement to issue assembly directives that create a self-relative +reference to the given @var{label}, using an integer of the given @var{size}. +@end defmac + +@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *@var{FILE}, int @var{size}, rtx @var{x}) +If defined, this target hook is a function which outputs a DTP-relative +reference to the given TLS symbol of the specified size. +@end deftypefn + +@defmac PUT_SDB_@dots{} +Define these macros to override the assembler syntax for the special +SDB assembler directives. See @file{sdbout.c} for a list of these +macros and their arguments. If the standard syntax is used, you need +not define them yourself. +@end defmac + +@defmac SDB_DELIM +Some assemblers do not support a semicolon as a delimiter, even between +SDB assembler directives. In that case, define this macro to be the +delimiter to use (usually @samp{\n}). It is not necessary to define +a new set of @code{PUT_SDB_@var{op}} macros if this is the only change +required. +@end defmac + +@defmac SDB_ALLOW_UNKNOWN_REFERENCES +Define this macro to allow references to unknown structure, +union, or enumeration tags to be emitted. Standard COFF does not +allow handling of unknown references, MIPS ECOFF has support for +it. +@end defmac + +@defmac SDB_ALLOW_FORWARD_REFERENCES +Define this macro to allow references to structure, union, or +enumeration tags that have not yet been seen to be handled. Some +assemblers choke if forward tags are used, while some require it. +@end defmac + +@defmac SDB_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}) +A C statement to output SDB debugging information before code for line +number @var{line} of the current source file to the stdio stream +@var{stream}. The default is to emit an @code{.ln} directive. +@end defmac + +@need 2000 +@node VMS Debug +@subsection Macros for VMS Debug Format + +@c prevent bad page break with this line +Here are macros for VMS debug format. + +@defmac VMS_DEBUGGING_INFO +Define this macro if GCC should produce debugging output for VMS +in response to the @option{-g} option. The default behavior for VMS +is to generate minimal debug info for a traceback in the absence of +@option{-g} unless explicitly overridden with @option{-g0}. This +behavior is controlled by @code{OPTIMIZATION_OPTIONS} and +@code{OVERRIDE_OPTIONS}. +@end defmac + +@node Floating Point +@section Cross Compilation and Floating Point +@cindex cross compilation and floating point +@cindex floating point and cross compilation + +While all modern machines use twos-complement representation for integers, +there are a variety of representations for floating point numbers. This +means that in a cross-compiler the representation of floating point numbers +in the compiled program may be different from that used in the machine +doing the compilation. + +Because different representation systems may offer different amounts of +range and precision, all floating point constants must be represented in +the target machine's format. Therefore, the cross compiler cannot +safely use the host machine's floating point arithmetic; it must emulate +the target's arithmetic. To ensure consistency, GCC always uses +emulation to work with floating point values, even when the host and +target floating point formats are identical. + +The following macros are provided by @file{real.h} for the compiler to +use. All parts of the compiler which generate or optimize +floating-point calculations must use these macros. They may evaluate +their operands more than once, so operands must not have side effects. + +@defmac REAL_VALUE_TYPE +The C data type to be used to hold a floating point value in the target +machine's format. Typically this is a @code{struct} containing an +array of @code{HOST_WIDE_INT}, but all code should treat it as an opaque +quantity. +@end defmac + +@deftypefn Macro int REAL_VALUES_EQUAL (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y}) +Compares for equality the two values, @var{x} and @var{y}. If the target +floating point format supports negative zeroes and/or NaNs, +@samp{REAL_VALUES_EQUAL (-0.0, 0.0)} is true, and +@samp{REAL_VALUES_EQUAL (NaN, NaN)} is false. +@end deftypefn + +@deftypefn Macro int REAL_VALUES_LESS (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y}) +Tests whether @var{x} is less than @var{y}. +@end deftypefn + +@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x}) +Truncates @var{x} to a signed integer, rounding toward zero. +@end deftypefn + +@deftypefn Macro {unsigned HOST_WIDE_INT} REAL_VALUE_UNSIGNED_FIX (REAL_VALUE_TYPE @var{x}) +Truncates @var{x} to an unsigned integer, rounding toward zero. If +@var{x} is negative, returns zero. +@end deftypefn + +@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, enum machine_mode @var{mode}) +Converts @var{string} into a floating point number in the target machine's +representation for mode @var{mode}. This routine can handle both +decimal and hexadecimal floating point constants, using the syntax +defined by the C language for both. +@end deftypefn + +@deftypefn Macro int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE @var{x}) +Returns 1 if @var{x} is negative (including negative zero), 0 otherwise. +@end deftypefn + +@deftypefn Macro int REAL_VALUE_ISINF (REAL_VALUE_TYPE @var{x}) +Determines whether @var{x} represents infinity (positive or negative). +@end deftypefn + +@deftypefn Macro int REAL_VALUE_ISNAN (REAL_VALUE_TYPE @var{x}) +Determines whether @var{x} represents a ``NaN'' (not-a-number). +@end deftypefn + +@deftypefn Macro void REAL_ARITHMETIC (REAL_VALUE_TYPE @var{output}, enum tree_code @var{code}, REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y}) +Calculates an arithmetic operation on the two floating point values +@var{x} and @var{y}, storing the result in @var{output} (which must be a +variable). + +The operation to be performed is specified by @var{code}. Only the +following codes are supported: @code{PLUS_EXPR}, @code{MINUS_EXPR}, +@code{MULT_EXPR}, @code{RDIV_EXPR}, @code{MAX_EXPR}, @code{MIN_EXPR}. + +If @code{REAL_ARITHMETIC} is asked to evaluate division by zero and the +target's floating point format cannot represent infinity, it will call +@code{abort}. Callers should check for this situation first, using +@code{MODE_HAS_INFINITIES}. @xref{Storage Layout}. +@end deftypefn + +@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE @var{x}) +Returns the negative of the floating point value @var{x}. +@end deftypefn + +@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE @var{x}) +Returns the absolute value of @var{x}. +@end deftypefn + +@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_TRUNCATE (REAL_VALUE_TYPE @var{mode}, enum machine_mode @var{x}) +Truncates the floating point value @var{x} to fit in @var{mode}. The +return value is still a full-size @code{REAL_VALUE_TYPE}, but it has an +appropriate bit pattern to be output asa floating constant whose +precision accords with mode @var{mode}. +@end deftypefn + +@deftypefn Macro void REAL_VALUE_TO_INT (HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, REAL_VALUE_TYPE @var{x}) +Converts a floating point value @var{x} into a double-precision integer +which is then stored into @var{low} and @var{high}. If the value is not +integral, it is truncated. +@end deftypefn + +@deftypefn Macro void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE @var{x}, HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, enum machine_mode @var{mode}) +Converts a double-precision integer found in @var{low} and @var{high}, +into a floating point value which is then stored into @var{x}. The +value is truncated to fit in mode @var{mode}. +@end deftypefn + +@node Mode Switching +@section Mode Switching Instructions +@cindex mode switching +The following macros control mode switching optimizations: + +@defmac OPTIMIZE_MODE_SWITCHING (@var{entity}) +Define this macro if the port needs extra instructions inserted for mode +switching in an optimizing compilation. + +For an example, the SH4 can perform both single and double precision +floating point operations, but to perform a single precision operation, +the FPSCR PR bit has to be cleared, while for a double precision +operation, this bit has to be set. Changing the PR bit requires a general +purpose register as a scratch register, hence these FPSCR sets have to +be inserted before reload, i.e.@: you can't put this into instruction emitting +or @code{TARGET_MACHINE_DEPENDENT_REORG}. + +You can have multiple entities that are mode-switched, and select at run time +which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should +return nonzero for any @var{entity} that needs mode-switching. +If you define this macro, you also have to define +@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED}, +@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}. +@code{MODE_AFTER}, @code{MODE_ENTRY}, and @code{MODE_EXIT} +are optional. +@end defmac + +@defmac NUM_MODES_FOR_MODE_SWITCHING +If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as +initializer for an array of integers. Each initializer element +N refers to an entity that needs mode switching, and specifies the number +of different modes that might need to be set for this entity. +The position of the initializer in the initializer---starting counting at +zero---determines the integer that is used to refer to the mode-switched +entity in question. +In macros that take mode arguments / yield a mode result, modes are +represented as numbers 0 @dots{} N @minus{} 1. N is used to specify that no mode +switch is needed / supplied. +@end defmac + +@defmac MODE_NEEDED (@var{entity}, @var{insn}) +@var{entity} is an integer specifying a mode-switched entity. If +@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to +return an integer value not larger than the corresponding element in +@code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must +be switched into prior to the execution of @var{insn}. +@end defmac + +@defmac MODE_AFTER (@var{mode}, @var{insn}) +If this macro is defined, it is evaluated for every @var{insn} during +mode switching. It determines the mode that an insn results in (if +different from the incoming mode). +@end defmac + +@defmac MODE_ENTRY (@var{entity}) +If this macro is defined, it is evaluated for every @var{entity} that needs +mode switching. It should evaluate to an integer, which is a mode that +@var{entity} is assumed to be switched to at function entry. If @code{MODE_ENTRY} +is defined then @code{MODE_EXIT} must be defined. +@end defmac + +@defmac MODE_EXIT (@var{entity}) +If this macro is defined, it is evaluated for every @var{entity} that needs +mode switching. It should evaluate to an integer, which is a mode that +@var{entity} is assumed to be switched to at function exit. If @code{MODE_EXIT} +is defined then @code{MODE_ENTRY} must be defined. +@end defmac + +@defmac MODE_PRIORITY_TO_MODE (@var{entity}, @var{n}) +This macro specifies the order in which modes for @var{entity} are processed. +0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the +lowest. The value of the macro should be an integer designating a mode +for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode} +(@var{entity}, @var{n}) shall be a bijection in 0 @dots{} +@code{num_modes_for_mode_switching[@var{entity}] - 1}. +@end defmac + +@defmac EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live}) +Generate one or more insns to set @var{entity} to @var{mode}. +@var{hard_reg_live} is the set of hard registers live at the point where +the insn(s) are to be inserted. +@end defmac + +@node Target Attributes +@section Defining target-specific uses of @code{__attribute__} +@cindex target attributes +@cindex machine attributes +@cindex attributes, target-specific + +Target-specific attributes may be defined for functions, data and types. +These are described using the following target hooks; they also need to +be documented in @file{extend.texi}. + +@deftypevr {Target Hook} {const struct attribute_spec *} TARGET_ATTRIBUTE_TABLE +If defined, this target hook points to an array of @samp{struct +attribute_spec} (defined in @file{tree.h}) specifying the machine +specific attributes for this target and some of the restrictions on the +entities to which these attributes are applied and the arguments they +take. +@end deftypevr + +@deftypefn {Target Hook} int TARGET_COMP_TYPE_ATTRIBUTES (tree @var{type1}, tree @var{type2}) +If defined, this target hook is a function which returns zero if the attributes on +@var{type1} and @var{type2} are incompatible, one if they are compatible, +and two if they are nearly compatible (which causes a warning to be +generated). If this is not defined, machine-specific attributes are +supposed always to be compatible. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_SET_DEFAULT_TYPE_ATTRIBUTES (tree @var{type}) +If defined, this target hook is a function which assigns default attributes to +newly defined @var{type}. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_MERGE_TYPE_ATTRIBUTES (tree @var{type1}, tree @var{type2}) +Define this target hook if the merging of type attributes needs special +handling. If defined, the result is a list of the combined +@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed +that @code{comptypes} has already been called and returned 1. This +function may call @code{merge_attributes} to handle machine-independent +merging. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_MERGE_DECL_ATTRIBUTES (tree @var{olddecl}, tree @var{newdecl}) +Define this target hook if the merging of decl attributes needs special +handling. If defined, the result is a list of the combined +@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}. +@var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of +when this is needed are when one attribute overrides another, or when an +attribute is nullified by a subsequent definition. This function may +call @code{merge_attributes} to handle machine-independent merging. + +@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES +If the only target-specific handling you require is @samp{dllimport} +for Microsoft Windows targets, you should define the macro +@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler +will then define a function called +@code{merge_dllimport_decl_attributes} which can then be defined as +the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also +add @code{handle_dll_attribute} in the attribute table for your port +to perform initial processing of the @samp{dllimport} and +@samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and +@file{i386/i386.c}, for example. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_VALID_DLLIMPORT_ATTRIBUTE_P (tree @var{decl}) +@var{decl} is a variable or function with @code{__attribute__((dllimport))} +specified. Use this hook if the target needs to add extra validation +checks to @code{handle_dll_attribute}. +@end deftypefn + +@defmac TARGET_DECLSPEC +Define this macro to a nonzero value if you want to treat +@code{__declspec(X)} as equivalent to @code{__attribute((X))}. By +default, this behavior is enabled only for targets that define +@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}. The current implementation +of @code{__declspec} is via a built-in macro, but you should not rely +on this implementation detail. +@end defmac + +@deftypefn {Target Hook} void TARGET_INSERT_ATTRIBUTES (tree @var{node}, tree *@var{attr_ptr}) +Define this target hook if you want to be able to add attributes to a decl +when it is being created. This is normally useful for back ends which +wish to implement a pragma by using the attributes which correspond to +the pragma's effect. The @var{node} argument is the decl which is being +created. The @var{attr_ptr} argument is a pointer to the attribute list +for this decl. The list itself should not be modified, since it may be +shared with other decls, but attributes may be chained on the head of +the list and @code{*@var{attr_ptr}} modified to point to the new +attributes, or a copy of the list may be made if further changes are +needed. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P (tree @var{fndecl}) +@cindex inlining +This target hook returns @code{true} if it is ok to inline @var{fndecl} +into the current function, despite its having target-specific +attributes, @code{false} otherwise. By default, if a function has a +target specific attribute attached to it, it will not be inlined. +@end deftypefn + +@node MIPS Coprocessors +@section Defining coprocessor specifics for MIPS targets. +@cindex MIPS coprocessor-definition macros + +The MIPS specification allows MIPS implementations to have as many as 4 +coprocessors, each with as many as 32 private registers. GCC supports +accessing these registers and transferring values between the registers +and memory using asm-ized variables. For example: + +@smallexample + register unsigned int cp0count asm ("c0r1"); + unsigned int d; + + d = cp0count + 3; +@end smallexample + +(``c0r1'' is the default name of register 1 in coprocessor 0; alternate +names may be added as described below, or the default names may be +overridden entirely in @code{SUBTARGET_CONDITIONAL_REGISTER_USAGE}.) + +Coprocessor registers are assumed to be epilogue-used; sets to them will +be preserved even if it does not appear that the register is used again +later in the function. + +Another note: according to the MIPS spec, coprocessor 1 (if present) is +the FPU@. One accesses COP1 registers through standard mips +floating-point support; they are not included in this mechanism. + +There is one macro used in defining the MIPS coprocessor interface which +you may want to override in subtargets; it is described below. + +@defmac ALL_COP_ADDITIONAL_REGISTER_NAMES +A comma-separated list (with leading comma) of pairs describing the +alternate names of coprocessor registers. The format of each entry should be +@smallexample +@{ @var{alternatename}, @var{register_number}@} +@end smallexample +Default: empty. +@end defmac + +@node PCH Target +@section Parameters for Precompiled Header Validity Checking +@cindex parameters, precompiled headers + +@deftypefn {Target Hook} void *TARGET_GET_PCH_VALIDITY (size_t *@var{sz}) +This hook returns the data needed by @code{TARGET_PCH_VALID_P} and sets +@samp{*@var{sz}} to the size of the data in bytes. +@end deftypefn + +@deftypefn {Target Hook} const char *TARGET_PCH_VALID_P (const void *@var{data}, size_t @var{sz}) +This hook checks whether the options used to create a PCH file are +compatible with the current settings. It returns @code{NULL} +if so and a suitable error message if not. Error messages will +be presented to the user and must be localized using @samp{_(@var{msg})}. + +@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY} +when the PCH file was created and @var{sz} is the size of that data in bytes. +It's safe to assume that the data was created by the same version of the +compiler, so no format checking is needed. + +The default definition of @code{default_pch_valid_p} should be +suitable for most targets. +@end deftypefn + +@deftypefn {Target Hook} const char *TARGET_CHECK_PCH_TARGET_FLAGS (int @var{pch_flags}) +If this hook is nonnull, the default implementation of +@code{TARGET_PCH_VALID_P} will use it to check for compatible values +of @code{target_flags}. @var{pch_flags} specifies the value that +@code{target_flags} had when the PCH file was created. The return +value is the same as for @code{TARGET_PCH_VALID_P}. +@end deftypefn + +@node C++ ABI +@section C++ ABI parameters +@cindex parameters, c++ abi + +@deftypefn {Target Hook} tree TARGET_CXX_GUARD_TYPE (void) +Define this hook to override the integer type used for guard variables. +These are used to implement one-time construction of static objects. The +default is long_long_integer_type_node. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_GUARD_MASK_BIT (void) +This hook determines how guard variables are used. It should return +@code{false} (the default) if first byte should be used. A return value of +@code{true} indicates the least significant bit should be used. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_CXX_GET_COOKIE_SIZE (tree @var{type}) +This hook returns the size of the cookie to use when allocating an array +whose elements have the indicated @var{type}. Assumes that it is already +known that a cookie is needed. The default is +@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the +IA64/Generic C++ ABI@. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_COOKIE_HAS_SIZE (void) +This hook should return @code{true} if the element size should be stored in +array cookies. The default is to return @code{false}. +@end deftypefn + +@deftypefn {Target Hook} int TARGET_CXX_IMPORT_EXPORT_CLASS (tree @var{type}, int @var{import_export}) +If defined by a backend this hook allows the decision made to export +class @var{type} to be overruled. Upon entry @var{import_export} +will contain 1 if the class is going to be exported, @minus{}1 if it is going +to be imported and 0 otherwise. This function should return the +modified value and perform any other actions necessary to support the +backend's targeted operating system. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_CDTOR_RETURNS_THIS (void) +This hook should return @code{true} if constructors and destructors return +the address of the object created/destroyed. The default is to return +@code{false}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_KEY_METHOD_MAY_BE_INLINE (void) +This hook returns true if the key method for a class (i.e., the method +which, if defined in the current translation unit, causes the virtual +table to be emitted) may be an inline function. Under the standard +Itanium C++ ABI the key method may be an inline function so long as +the function is not declared inline in the class definition. Under +some variants of the ABI, an inline function can never be the key +method. The default is to return @code{true}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY (tree @var{decl}) +@var{decl} is a virtual table, virtual table table, typeinfo object, +or other similar implicit class data object that will be emitted with +external linkage in this translation unit. No ELF visibility has been +explicitly specified. If the target needs to specify a visibility +other than that of the containing class, use this hook to set +@code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT (void) +This hook returns true (the default) if virtual tables and other +similar implicit class data objects are always COMDAT if they have +external linkage. If this hook returns false, then class data for +classes whose virtual table will be emitted in only one translation +unit will not be COMDAT. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_CXX_USE_AEABI_ATEXIT (void) +This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI) +should be used to register static destructors when @option{-fuse-cxa-atexit} +is in effect. The default is to return false to use @code{__cxa_atexit}. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree @var{type}) +@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just been +defined. Use this hook to make adjustments to the class (eg, tweak +visibility or perform any other required target modifications). +@end deftypefn + +@c APPLE LOCAL begin mainline 4.3 2006-01-10 4871915 +@deftypefn {Target Hook} bool TARGET_CXX_LIBRARY_RTTI_COMDAT (void) +This hook returns true (the default) if the RTTI information for +the basic types which is defined in the C++ runtime should always +be COMDAT, false if it should not be COMDAT. +@end deftypefn + +@c APPLE LOCAL end mainline 4.3 2006-01-10 4871915 +@node Misc +@section Miscellaneous Parameters +@cindex parameters, miscellaneous + +@c prevent bad page break with this line +Here are several miscellaneous parameters. + +@defmac HAS_LONG_COND_BRANCH +Define this boolean macro to indicate whether or not your architecture +has conditional branches that can span all of memory. It is used in +conjunction with an optimization that partitions hot and cold basic +blocks into separate sections of the executable. If this macro is +set to false, gcc will convert any conditional branches that attempt +to cross between sections into unconditional branches or indirect jumps. +@end defmac + +@defmac HAS_LONG_UNCOND_BRANCH +Define this boolean macro to indicate whether or not your architecture +has unconditional branches that can span all of memory. It is used in +conjunction with an optimization that partitions hot and cold basic +blocks into separate sections of the executable. If this macro is +set to false, gcc will convert any unconditional branches that attempt +to cross between sections into indirect jumps. +@end defmac + +@defmac CASE_VECTOR_MODE +An alias for a machine mode name. This is the machine mode that +elements of a jump-table should have. +@end defmac + +@defmac CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body}) +Optional: return the preferred mode for an @code{addr_diff_vec} +when the minimum and maximum offset are known. If you define this, +it enables extra code in branch shortening to deal with @code{addr_diff_vec}. +To make this work, you also have to define @code{INSN_ALIGN} and +make the alignment for @code{addr_diff_vec} explicit. +The @var{body} argument is provided so that the offset_unsigned and scale +flags can be updated. +@end defmac + +@defmac CASE_VECTOR_PC_RELATIVE +Define this macro to be a C expression to indicate when jump-tables +should contain relative addresses. You need not define this macro if +jump-tables never contain relative addresses, or jump-tables should +contain relative addresses only when @option{-fPIC} or @option{-fPIC} +is in effect. +@end defmac + +@defmac CASE_VALUES_THRESHOLD +Define this to be the smallest number of different values for which it +is best to use a jump-table instead of a tree of conditional branches. +The default is four for machines with a @code{casesi} instruction and +five otherwise. This is best for most machines. +@end defmac + +@defmac CASE_USE_BIT_TESTS +Define this macro to be a C expression to indicate whether C switch +statements may be implemented by a sequence of bit tests. This is +advantageous on processors that can efficiently implement left shift +of 1 by the number of bits held in a register, but inappropriate on +targets that would require a loop. By default, this macro returns +@code{true} if the target defines an @code{ashlsi3} pattern, and +@code{false} otherwise. +@end defmac + +@defmac WORD_REGISTER_OPERATIONS +Define this macro if operations between registers with integral mode +smaller than a word are always performed on the entire register. +Most RISC machines have this property and most CISC machines do not. +@end defmac + +@defmac LOAD_EXTEND_OP (@var{mem_mode}) +Define this macro to be a C expression indicating when insns that read +memory in @var{mem_mode}, an integral mode narrower than a word, set the +bits outside of @var{mem_mode} to be either the sign-extension or the +zero-extension of the data read. Return @code{SIGN_EXTEND} for values +of @var{mem_mode} for which the +insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and +@code{UNKNOWN} for other modes. + +This macro is not called with @var{mem_mode} non-integral or with a width +greater than or equal to @code{BITS_PER_WORD}, so you may return any +value in this case. Do not define this macro if it would always return +@code{UNKNOWN}. On machines where this macro is defined, you will normally +define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}. + +You may return a non-@code{UNKNOWN} value even if for some hard registers +the sign extension is not performed, if for the @code{REGNO_REG_CLASS} +of these hard registers @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero +when the @var{from} mode is @var{mem_mode} and the @var{to} mode is any +integral mode larger than this but not larger than @code{word_mode}. + +You must return @code{UNKNOWN} if for some hard registers that allow this +mode, @code{CANNOT_CHANGE_MODE_CLASS} says that they cannot change to +@code{word_mode}, but that they can change to another integral mode that +is larger then @var{mem_mode} but still smaller than @code{word_mode}. +@end defmac + +@defmac SHORT_IMMEDIATES_SIGN_EXTEND +Define this macro if loading short immediate values into registers sign +extends. +@end defmac + +@defmac FIXUNS_TRUNC_LIKE_FIX_TRUNC +Define this macro if the same instructions that convert a floating +point number to a signed fixed point number also convert validly to an +unsigned one. +@end defmac + +@deftypefn {Target Hook} int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum machine_mode @var{mode}) +When @option{-ffast-math} is in effect, GCC tries to optimize +divisions by the same divisor, by turning them into multiplications by +the reciprocal. This target hook specifies the minimum number of divisions +that should be there for GCC to perform the optimization for a variable +of mode @var{mode}. The default implementation returns 3 if the machine +has an instruction for the division, and 2 if it does not. +@end deftypefn + +@defmac MOVE_MAX +The maximum number of bytes that a single instruction can move quickly +between memory and registers or between two memory locations. +@end defmac + +@defmac MAX_MOVE_MAX +The maximum number of bytes that a single instruction can move quickly +between memory and registers or between two memory locations. If this +is undefined, the default is @code{MOVE_MAX}. Otherwise, it is the +constant value that is the largest value that @code{MOVE_MAX} can have +at run-time. +@end defmac + +@defmac SHIFT_COUNT_TRUNCATED +A C expression that is nonzero if on this machine the number of bits +actually used for the count of a shift operation is equal to the number +of bits needed to represent the size of the object being shifted. When +this macro is nonzero, the compiler will assume that it is safe to omit +a sign-extend, zero-extend, and certain bitwise `and' instructions that +truncates the count of a shift operation. On machines that have +instructions that act on bit-fields at variable positions, which may +include `bit test' instructions, a nonzero @code{SHIFT_COUNT_TRUNCATED} +also enables deletion of truncations of the values that serve as +arguments to bit-field instructions. + +If both types of instructions truncate the count (for shifts) and +position (for bit-field operations), or if no variable-position bit-field +instructions exist, you should define this macro. + +However, on some machines, such as the 80386 and the 680x0, truncation +only applies to shift operations and not the (real or pretended) +bit-field operations. Define @code{SHIFT_COUNT_TRUNCATED} to be zero on +such machines. Instead, add patterns to the @file{md} file that include +the implied truncation of the shift instructions. + +You need not define this macro if it would always have the value of zero. +@end defmac + +@anchor{TARGET_SHIFT_TRUNCATION_MASK} +@deftypefn {Target Hook} int TARGET_SHIFT_TRUNCATION_MASK (enum machine_mode @var{mode}) +This function describes how the standard shift patterns for @var{mode} +deal with shifts by negative amounts or by more than the width of the mode. +@xref{shift patterns}. + +On many machines, the shift patterns will apply a mask @var{m} to the +shift count, meaning that a fixed-width shift of @var{x} by @var{y} is +equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If +this is true for mode @var{mode}, the function should return @var{m}, +otherwise it should return 0. A return value of 0 indicates that no +particular behavior is guaranteed. + +Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does +@emph{not} apply to general shift rtxes; it applies only to instructions +that are generated by the named shift patterns. + +The default implementation of this function returns +@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED} +and 0 otherwise. This definition is always safe, but if +@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns +nevertheless truncate the shift count, you may get better code +by overriding it. +@end deftypefn + +@defmac TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec}) +A C expression which is nonzero if on this machine it is safe to +``convert'' an integer of @var{inprec} bits to one of @var{outprec} +bits (where @var{outprec} is smaller than @var{inprec}) by merely +operating on it as if it had only @var{outprec} bits. + +On many machines, this expression can be 1. + +@c rearranged this, removed the phrase "it is reported that". this was +@c to fix an overfull hbox. --mew 10feb93 +When @code{TRULY_NOOP_TRUNCATION} returns 1 for a pair of sizes for +modes for which @code{MODES_TIEABLE_P} is 0, suboptimal code can result. +If this is the case, making @code{TRULY_NOOP_TRUNCATION} return 0 in +such cases may improve things. +@end defmac + +@deftypefn {Target Hook} int TARGET_MODE_REP_EXTENDED (enum machine_mode @var{mode}, enum machine_mode @var{rep_mode}) +The representation of an integral mode can be such that the values +are always extended to a wider integral mode. Return +@code{SIGN_EXTEND} if values of @var{mode} are represented in +sign-extended form to @var{rep_mode}. Return @code{UNKNOWN} +otherwise. (Currently, none of the targets use zero-extended +representation this way so unlike @code{LOAD_EXTEND_OP}, +@code{TARGET_MODE_REP_EXTENDED} is expected to return either +@code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends +@var{mode} to @var{mode_rep} so that @var{mode_rep} is not the next +widest integral mode and currently we take advantage of this fact.) + +Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN} +value even if the extension is not performed on certain hard registers +as long as for the @code{REGNO_REG_CLASS} of these hard registers +@code{CANNOT_CHANGE_MODE_CLASS} returns nonzero. + +Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP} +describe two related properties. If you define +@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want +to define @code{LOAD_EXTEND_OP (mode)} to return the same type of +extension. + +In order to enforce the representation of @code{mode}, +@code{TRULY_NOOP_TRUNCATION} should return false when truncating to +@code{mode}. +@end deftypefn + +@defmac STORE_FLAG_VALUE +A C expression describing the value returned by a comparison operator +with an integral mode and stored by a store-flag instruction +(@samp{s@var{cond}}) when the condition is true. This description must +apply to @emph{all} the @samp{s@var{cond}} patterns and all the +comparison operators whose results have a @code{MODE_INT} mode. + +A value of 1 or @minus{}1 means that the instruction implementing the +comparison operator returns exactly 1 or @minus{}1 when the comparison is true +and 0 when the comparison is false. Otherwise, the value indicates +which bits of the result are guaranteed to be 1 when the comparison is +true. This value is interpreted in the mode of the comparison +operation, which is given by the mode of the first operand in the +@samp{s@var{cond}} pattern. Either the low bit or the sign bit of +@code{STORE_FLAG_VALUE} be on. Presently, only those bits are used by +the compiler. + +If @code{STORE_FLAG_VALUE} is neither 1 or @minus{}1, the compiler will +generate code that depends only on the specified bits. It can also +replace comparison operators with equivalent operations if they cause +the required bits to be set, even if the remaining bits are undefined. +For example, on a machine whose comparison operators return an +@code{SImode} value and where @code{STORE_FLAG_VALUE} is defined as +@samp{0x80000000}, saying that just the sign bit is relevant, the +expression + +@smallexample +(ne:SI (and:SI @var{x} (const_int @var{power-of-2})) (const_int 0)) +@end smallexample + +@noindent +can be converted to + +@smallexample +(ashift:SI @var{x} (const_int @var{n})) +@end smallexample + +@noindent +where @var{n} is the appropriate shift count to move the bit being +tested into the sign bit. + +There is no way to describe a machine that always sets the low-order bit +for a true value, but does not guarantee the value of any other bits, +but we do not know of any machine that has such an instruction. If you +are trying to port GCC to such a machine, include an instruction to +perform a logical-and of the result with 1 in the pattern for the +comparison operators and let us know at @email{gcc@@gcc.gnu.org}. + +Often, a machine will have multiple instructions that obtain a value +from a comparison (or the condition codes). Here are rules to guide the +choice of value for @code{STORE_FLAG_VALUE}, and hence the instructions +to be used: + +@itemize @bullet +@item +Use the shortest sequence that yields a valid definition for +@code{STORE_FLAG_VALUE}. It is more efficient for the compiler to +``normalize'' the value (convert it to, e.g., 1 or 0) than for the +comparison operators to do so because there may be opportunities to +combine the normalization with other operations. + +@item +For equal-length sequences, use a value of 1 or @minus{}1, with @minus{}1 being +slightly preferred on machines with expensive jumps and 1 preferred on +other machines. + +@item +As a second choice, choose a value of @samp{0x80000001} if instructions +exist that set both the sign and low-order bits but do not define the +others. + +@item +Otherwise, use a value of @samp{0x80000000}. +@end itemize + +Many machines can produce both the value chosen for +@code{STORE_FLAG_VALUE} and its negation in the same number of +instructions. On those machines, you should also define a pattern for +those cases, e.g., one matching + +@smallexample +(set @var{A} (neg:@var{m} (ne:@var{m} @var{B} @var{C}))) +@end smallexample + +Some machines can also perform @code{and} or @code{plus} operations on +condition code values with less instructions than the corresponding +@samp{s@var{cond}} insn followed by @code{and} or @code{plus}. On those +machines, define the appropriate patterns. Use the names @code{incscc} +and @code{decscc}, respectively, for the patterns which perform +@code{plus} or @code{minus} operations on condition code values. See +@file{rs6000.md} for some examples. The GNU Superoptizer can be used to +find such instruction sequences on other machines. + +If this macro is not defined, the default value, 1, is used. You need +not define @code{STORE_FLAG_VALUE} if the machine has no store-flag +instructions, or if the value generated by these instructions is 1. +@end defmac + +@defmac FLOAT_STORE_FLAG_VALUE (@var{mode}) +A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is +returned when comparison operators with floating-point results are true. +Define this macro on machines that have comparison operations that return +floating-point values. If there are no such operations, do not define +this macro. +@end defmac + +@defmac VECTOR_STORE_FLAG_VALUE (@var{mode}) +A C expression that gives a rtx representing the nonzero true element +for vector comparisons. The returned rtx should be valid for the inner +mode of @var{mode} which is guaranteed to be a vector mode. Define +this macro on machines that have vector comparison operations that +return a vector result. If there are no such operations, do not define +this macro. Typically, this macro is defined as @code{const1_rtx} or +@code{constm1_rtx}. This macro may return @code{NULL_RTX} to prevent +the compiler optimizing such vector comparison operations for the +given mode. +@end defmac + +@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value}) +@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value}) +A C expression that evaluates to true if the architecture defines a value +for @code{clz} or @code{ctz} with a zero operand. If so, @var{value} +should be set to this value. If this macro is not defined, the value of +@code{clz} or @code{ctz} is assumed to be undefined. + +This macro must be defined if the target's expansion for @code{ffs} +relies on a particular value to get correct results. Otherwise it +is not necessary, though it may be used to optimize some corner cases. + +Note that regardless of this macro the ``definedness'' of @code{clz} +and @code{ctz} at zero do @emph{not} extend to the builtin functions +visible to the user. Thus one may be free to adjust the value at will +to match the target expansion of these operations without fear of +breaking the API@. +@end defmac + +@defmac Pmode +An alias for the machine mode for pointers. On most machines, define +this to be the integer mode corresponding to the width of a hardware +pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines. +On some machines you must define this to be one of the partial integer +modes, such as @code{PSImode}. + +The width of @code{Pmode} must be at least as large as the value of +@code{POINTER_SIZE}. If it is not equal, you must define the macro +@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended +to @code{Pmode}. +@end defmac + +@defmac FUNCTION_MODE +An alias for the machine mode used for memory references to functions +being called, in @code{call} RTL expressions. On most machines this +should be @code{QImode}. +@end defmac + +@defmac STDC_0_IN_SYSTEM_HEADERS +In normal operation, the preprocessor expands @code{__STDC__} to the +constant 1, to signify that GCC conforms to ISO Standard C@. On some +hosts, like Solaris, the system compiler uses a different convention, +where @code{__STDC__} is normally 0, but is 1 if the user specifies +strict conformance to the C Standard. + +Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host +convention when processing system header files, but when processing user +files @code{__STDC__} will always expand to 1. +@end defmac + +@defmac NO_IMPLICIT_EXTERN_C +Define this macro if the system header files support C++ as well as C@. +This macro inhibits the usual method of using system header files in +C++, which is to pretend that the file's contents are enclosed in +@samp{extern "C" @{@dots{}@}}. +@end defmac + +@findex #pragma +@findex pragma +@defmac REGISTER_TARGET_PRAGMAS () +Define this macro if you want to implement any target-specific pragmas. +If defined, it is a C expression which makes a series of calls to +@code{c_register_pragma} or @code{c_register_pragma_with_expansion} +for each pragma. The macro may also do any +setup required for the pragmas. + +The primary reason to define this macro is to provide compatibility with +other compilers for the same target. In general, we discourage +definition of target-specific pragmas for GCC@. + +If the pragma can be implemented by attributes then you should consider +defining the target hook @samp{TARGET_INSERT_ATTRIBUTES} as well. + +Preprocessor macros that appear on pragma lines are not expanded. All +@samp{#pragma} directives that do not match any registered pragma are +silently ignored, unless the user specifies @option{-Wunknown-pragmas}. +@end defmac + +@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *)) +@deftypefunx void c_register_pragma_with_expansion (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *)) + +Each call to @code{c_register_pragma} or +@code{c_register_pragma_with_expansion} establishes one pragma. The +@var{callback} routine will be called when the preprocessor encounters a +pragma of the form + +@smallexample +#pragma [@var{space}] @var{name} @dots{} +@end smallexample + +@var{space} is the case-sensitive namespace of the pragma, or +@code{NULL} to put the pragma in the global namespace. The callback +routine receives @var{pfile} as its first argument, which can be passed +on to cpplib's functions if necessary. You can lex tokens after the +@var{name} by calling @code{pragma_lex}. Tokens that are not read by the +callback will be silently ignored. The end of the line is indicated by +a token of type @code{CPP_EOF}. Macro expansion occurs on the +arguments of pragmas registered with +@code{c_register_pragma_with_expansion} but not on the arguments of +pragmas registered with @code{c_register_pragma}. + +For an example use of this routine, see @file{c4x.h} and the callback +routines defined in @file{c4x-c.c}. + +Note that the use of @code{pragma_lex} is specific to the C and C++ +compilers. It will not work in the Java or Fortran compilers, or any +other language compilers for that matter. Thus if @code{pragma_lex} is going +to be called from target-specific code, it must only be done so when +building the C and C++ compilers. This can be done by defining the +variables @code{c_target_objs} and @code{cxx_target_objs} in the +target entry in the @file{config.gcc} file. These variables should name +the target-specific, language-specific object file which contains the +code that uses @code{pragma_lex}. Note it will also be necessary to add a +rule to the makefile fragment pointed to by @code{tmake_file} that shows +how to build this object file. +@end deftypefun + +@findex #pragma +@findex pragma +@defmac HANDLE_SYSV_PRAGMA +Define this macro (to a value of 1) if you want the System V style +pragmas @samp{#pragma pack(<n>)} and @samp{#pragma weak <name> +[=<value>]} to be supported by gcc. + +The pack pragma specifies the maximum alignment (in bytes) of fields +within a structure, in much the same way as the @samp{__aligned__} and +@samp{__packed__} @code{__attribute__}s do. A pack value of zero resets +the behavior to the default. + +A subtlety for Microsoft Visual C/C++ style bit-field packing +(e.g.@: -mms-bitfields) for targets that support it: +When a bit-field is inserted into a packed record, the whole size +of the underlying type is used by one or more same-size adjacent +bit-fields (that is, if its long:3, 32 bits is used in the record, +and any additional adjacent long bit-fields are packed into the same +chunk of 32 bits. However, if the size changes, a new field of that +size is allocated). + +If both MS bit-fields and @samp{__attribute__((packed))} are used, +the latter will take precedence. If @samp{__attribute__((packed))} is +used on a single field when MS bit-fields are in use, it will take +precedence for that field, but the alignment of the rest of the structure +may affect its placement. + +The weak pragma only works if @code{SUPPORTS_WEAK} and +@code{ASM_WEAKEN_LABEL} are defined. If enabled it allows the creation +of specifically named weak labels, optionally with a value. +@end defmac + +@findex #pragma +@findex pragma +@defmac HANDLE_PRAGMA_PACK_PUSH_POP +Define this macro (to a value of 1) if you want to support the Win32 +style pragmas @samp{#pragma pack(push[,@var{n}])} and @samp{#pragma +pack(pop)}. The @samp{pack(push,[@var{n}])} pragma specifies the maximum +alignment (in bytes) of fields within a structure, in much the same way as +the @samp{__aligned__} and @samp{__packed__} @code{__attribute__}s do. A +pack value of zero resets the behavior to the default. Successive +invocations of this pragma cause the previous values to be stacked, so +that invocations of @samp{#pragma pack(pop)} will return to the previous +value. +@end defmac + +@defmac HANDLE_PRAGMA_PACK_WITH_EXPANSION +Define this macro, as well as +@code{HANDLE_SYSV_PRAGMA}, if macros should be expanded in the +arguments of @samp{#pragma pack}. +@end defmac + +@defmac TARGET_DEFAULT_PACK_STRUCT +If your target requires a structure packing default other than 0 (meaning +the machine default), define this macro to the necessary value (in bytes). +This must be a value that would also be valid to use with +@samp{#pragma pack()} (that is, a small power of two). +@end defmac + +@defmac DOLLARS_IN_IDENTIFIERS +Define this macro to control use of the character @samp{$} in +identifier names for the C family of languages. 0 means @samp{$} is +not allowed by default; 1 means it is allowed. 1 is the default; +there is no need to define this macro in that case. +@end defmac + +@defmac NO_DOLLAR_IN_LABEL +Define this macro if the assembler does not accept the character +@samp{$} in label names. By default constructors and destructors in +G++ have @samp{$} in the identifiers. If this macro is defined, +@samp{.} is used instead. +@end defmac + +@defmac NO_DOT_IN_LABEL +Define this macro if the assembler does not accept the character +@samp{.} in label names. By default constructors and destructors in G++ +have names that use @samp{.}. If this macro is defined, these names +are rewritten to avoid @samp{.}. +@end defmac + +@defmac INSN_SETS_ARE_DELAYED (@var{insn}) +Define this macro as a C expression that is nonzero if it is safe for the +delay slot scheduler to place instructions in the delay slot of @var{insn}, +even if they appear to use a resource set or clobbered in @var{insn}. +@var{insn} is always a @code{jump_insn} or an @code{insn}; GCC knows that +every @code{call_insn} has this behavior. On machines where some @code{insn} +or @code{jump_insn} is really a function call and hence has this behavior, +you should define this macro. + +You need not define this macro if it would always return zero. +@end defmac + +@defmac INSN_REFERENCES_ARE_DELAYED (@var{insn}) +Define this macro as a C expression that is nonzero if it is safe for the +delay slot scheduler to place instructions in the delay slot of @var{insn}, +even if they appear to set or clobber a resource referenced in @var{insn}. +@var{insn} is always a @code{jump_insn} or an @code{insn}. On machines where +some @code{insn} or @code{jump_insn} is really a function call and its operands +are registers whose use is actually in the subroutine it calls, you should +define this macro. Doing so allows the delay slot scheduler to move +instructions which copy arguments into the argument registers into the delay +slot of @var{insn}. + +You need not define this macro if it would always return zero. +@end defmac + +@defmac MULTIPLE_SYMBOL_SPACES +Define this macro as a C expression that is nonzero if, in some cases, +global symbols from one translation unit may not be bound to undefined +symbols in another translation unit without user intervention. For +instance, under Microsoft Windows symbols must be explicitly imported +from shared libraries (DLLs). + +You need not define this macro if it would always evaluate to zero. +@end defmac + +@deftypefn {Target Hook} tree TARGET_MD_ASM_CLOBBERS (tree @var{outputs}, tree @var{inputs}, tree @var{clobbers}) +This target hook should add to @var{clobbers} @code{STRING_CST} trees for +any hard regs the port wishes to automatically clobber for an asm. +It should return the result of the last @code{tree_cons} used to add a +clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the +corresponding parameters to the asm and may be inspected to avoid +clobbering a register that is an input or output of the asm. You can use +@code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test +for overlap with regards to asm-declared registers. +@end deftypefn + +@defmac MATH_LIBRARY +Define this macro as a C string constant for the linker argument to link +in the system math library, or @samp{""} if the target does not have a +separate math library. + +You need only define this macro if the default of @samp{"-lm"} is wrong. +@end defmac + +@defmac LIBRARY_PATH_ENV +Define this macro as a C string constant for the environment variable that +specifies where the linker should look for libraries. + +You need only define this macro if the default of @samp{"LIBRARY_PATH"} +is wrong. +@end defmac + +@defmac TARGET_POSIX_IO +Define this macro if the target supports the following POSIX@ file +functions, access, mkdir and file locking with fcntl / F_SETLKW@. +Defining @code{TARGET_POSIX_IO} will enable the test coverage code +to use file locking when exiting a program, which avoids race conditions +if the program has forked. It will also create directories at run-time +for cross-profiling. +@end defmac + +@defmac MAX_CONDITIONAL_EXECUTE + +A C expression for the maximum number of instructions to execute via +conditional execution instructions instead of a branch. A value of +@code{BRANCH_COST}+1 is the default if the machine does not use cc0, and +1 if it does use cc0. +@end defmac + +@defmac IFCVT_MODIFY_TESTS (@var{ce_info}, @var{true_expr}, @var{false_expr}) +Used if the target needs to perform machine-dependent modifications on the +conditionals used for turning basic blocks into conditionally executed code. +@var{ce_info} points to a data structure, @code{struct ce_if_block}, which +contains information about the currently processed blocks. @var{true_expr} +and @var{false_expr} are the tests that are used for converting the +then-block and the else-block, respectively. Set either @var{true_expr} or +@var{false_expr} to a null pointer if the tests cannot be converted. +@end defmac + +@defmac IFCVT_MODIFY_MULTIPLE_TESTS (@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr}) +Like @code{IFCVT_MODIFY_TESTS}, but used when converting more complicated +if-statements into conditions combined by @code{and} and @code{or} operations. +@var{bb} contains the basic block that contains the test that is currently +being processed and about to be turned into a condition. +@end defmac + +@defmac IFCVT_MODIFY_INSN (@var{ce_info}, @var{pattern}, @var{insn}) +A C expression to modify the @var{PATTERN} of an @var{INSN} that is to +be converted to conditional execution format. @var{ce_info} points to +a data structure, @code{struct ce_if_block}, which contains information +about the currently processed blocks. +@end defmac + +@defmac IFCVT_MODIFY_FINAL (@var{ce_info}) +A C expression to perform any final machine dependent modifications in +converting code to conditional execution. The involved basic blocks +can be found in the @code{struct ce_if_block} structure that is pointed +to by @var{ce_info}. +@end defmac + +@defmac IFCVT_MODIFY_CANCEL (@var{ce_info}) +A C expression to cancel any machine dependent modifications in +converting code to conditional execution. The involved basic blocks +can be found in the @code{struct ce_if_block} structure that is pointed +to by @var{ce_info}. +@end defmac + +@defmac IFCVT_INIT_EXTRA_FIELDS (@var{ce_info}) +A C expression to initialize any extra fields in a @code{struct ce_if_block} +structure, which are defined by the @code{IFCVT_EXTRA_FIELDS} macro. +@end defmac + +@defmac IFCVT_EXTRA_FIELDS +If defined, it should expand to a set of field declarations that will be +added to the @code{struct ce_if_block} structure. These should be initialized +by the @code{IFCVT_INIT_EXTRA_FIELDS} macro. +@end defmac + +@deftypefn {Target Hook} void TARGET_MACHINE_DEPENDENT_REORG () +If non-null, this hook performs a target-specific pass over the +instruction stream. The compiler will run it at all optimization levels, +just before the point at which it normally does delayed-branch scheduling. + +The exact purpose of the hook varies from target to target. Some use +it to do transformations that are necessary for correctness, such as +laying out in-function constant pools or avoiding hardware hazards. +Others use it as an opportunity to do some machine-dependent optimizations. + +You need not implement the hook if it has nothing to do. The default +definition is null. +@end deftypefn + +@deftypefn {Target Hook} void TARGET_INIT_BUILTINS () +Define this hook if you have any machine-specific built-in functions +that need to be defined. It should be a function that performs the +necessary setup. + +Machine specific built-in functions can be useful to expand special machine +instructions that would otherwise not normally be generated because +they have no equivalent in the source language (for example, SIMD vector +instructions or prefetch instructions). + +To create a built-in function, call the function +@code{lang_hooks.builtin_function} +which is defined by the language front end. You can use any type nodes set +up by @code{build_common_tree_nodes} and @code{build_common_tree_nodes_2}; +only language front ends that use those two functions will call +@samp{TARGET_INIT_BUILTINS}. +@end deftypefn + +@deftypefn {Target Hook} rtx TARGET_EXPAND_BUILTIN (tree @var{exp}, rtx @var{target}, rtx @var{subtarget}, enum machine_mode @var{mode}, int @var{ignore}) + +Expand a call to a machine specific built-in function that was set up by +@samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the +function call; the result should go to @var{target} if that is +convenient, and have mode @var{mode} if that is convenient. +@var{subtarget} may be used as the target for computing one of +@var{exp}'s operands. @var{ignore} is nonzero if the value is to be +ignored. This function should return the result of the call to the +built-in function. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_RESOLVE_OVERLOADED_BUILTIN (tree @var{fndecl}, tree @var{arglist}) + +Select a replacement for a machine specific built-in function that +was set up by @samp{TARGET_INIT_BUILTINS}. This is done +@emph{before} regular type checking, and so allows the target to +implement a crude form of function overloading. @var{fndecl} is the +declaration of the built-in function. @var{arglist} is the list of +arguments passed to the built-in function. The result is a +complete expression that implements the operation, usually +another @code{CALL_EXPR}. +@end deftypefn + +@deftypefn {Target Hook} tree TARGET_FOLD_BUILTIN (tree @var{fndecl}, tree @var{arglist}, bool @var{ignore}) + +Fold a call to a machine specific built-in function that was set up by +@samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the +built-in function. @var{arglist} is the list of arguments passed to +the built-in function. The result is another tree containing a +simplified expression for the call's result. If @var{ignore} is true +the value will be ignored. +@end deftypefn + +@deftypefn {Target Hook} const char * TARGET_INVALID_WITHIN_DOLOOP (rtx @var{insn}) + +Take an instruction in @var{insn} and return NULL if it is valid within a +low-overhead loop, otherwise return a string why doloop could not be applied. + +Many targets use special registers for low-overhead looping. For any +instruction that clobbers these this function should return a string indicating +the reason why the doloop could not be applied. +By default, the RTL loop optimizer does not use a present doloop pattern for +loops containing function calls or branch on table instructions. +@end deftypefn + +@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2}) + +Take a branch insn in @var{branch1} and another in @var{branch2}. +Return true if redirecting @var{branch1} to the destination of +@var{branch2} is possible. + +On some targets, branches may have a limited range. Optimizing the +filling of delay slots can result in branches being redirected, and this +may in turn cause a branch offset to overflow. +@end defmac + +@deftypefn {Target Hook} bool TARGET_COMMUTATIVE_P (rtx @var{x}, @var{outer_code}) +This target hook returns @code{true} if @var{x} is considered to be commutative. +Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider +PLUS to be commutative inside a MEM. @var{outer_code} is the rtx code +of the enclosing rtl, if known, otherwise it is UNKNOWN. +@end deftypefn + +@deftypefn {Target Hook} rtx TARGET_ALLOCATE_INITIAL_VALUE (rtx @var{hard_reg}) + +When the initial value of a hard register has been copied in a pseudo +register, it is often not necessary to actually allocate another register +to this pseudo register, because the original hard register or a stack slot +it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE} +is called at the start of register allocation once for each hard register +that had its initial value copied by using +@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}. +Possible values are @code{NULL_RTX}, if you don't want +to do any special allocation, a @code{REG} rtx---that would typically be +the hard register itself, if it is known not to be clobbered---or a +@code{MEM}. +If you are returning a @code{MEM}, this is only a hint for the allocator; +it might decide to use another register anyways. +You may use @code{current_function_leaf_function} in the hook, functions +that use @code{REG_N_SETS}, to determine if the hard +register in question will not be clobbered. +The default value of this hook is @code{NULL}, which disables any special +allocation. +@end deftypefn + +@defmac TARGET_OBJECT_SUFFIX +Define this macro to be a C string representing the suffix for object +files on your target machine. If you do not define this macro, GCC will +use @samp{.o} as the suffix for object files. +@end defmac + +@defmac TARGET_EXECUTABLE_SUFFIX +Define this macro to be a C string representing the suffix to be +automatically added to executable files on your target machine. If you +do not define this macro, GCC will use the null string as the suffix for +executable files. +@end defmac + +@defmac COLLECT_EXPORT_LIST +If defined, @code{collect2} will scan the individual object files +specified on its command line and create an export list for the linker. +Define this macro for systems like AIX, where the linker discards +object files that are not referenced from @code{main} and uses export +lists. +@end defmac + +@defmac MODIFY_JNI_METHOD_CALL (@var{mdecl}) +Define this macro to a C expression representing a variant of the +method call @var{mdecl}, if Java Native Interface (JNI) methods +must be invoked differently from other methods on your target. +For example, on 32-bit Microsoft Windows, JNI methods must be invoked using +the @code{stdcall} calling convention and this macro is then +defined as this expression: + +@smallexample +build_type_attribute_variant (@var{mdecl}, + build_tree_list + (get_identifier ("stdcall"), + NULL)) +@end smallexample +@end defmac + +@deftypefn {Target Hook} bool TARGET_CANNOT_MODIFY_JUMPS_P (void) +This target hook returns @code{true} past the point in which new jump +instructions could be created. On machines that require a register for +every jump such as the SHmedia ISA of SH5, this point would typically be +reload, so this target hook should be defined to a function such as: + +@smallexample +static bool +cannot_modify_jumps_past_reload_p () +@{ + return (reload_completed || reload_in_progress); +@} +@end smallexample +@end deftypefn + +@deftypefn {Target Hook} int TARGET_BRANCH_TARGET_REGISTER_CLASS (void) +This target hook returns a register class for which branch target register +optimizations should be applied. All registers in this class should be +usable interchangeably. After reload, registers in this class will be +re-allocated and loads will be hoisted out of loops and be subjected +to inter-block scheduling. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED (bool @var{after_prologue_epilogue_gen}) +Branch target register optimization will by default exclude callee-saved +registers +that are not already live during the current function; if this target hook +returns true, they will be included. The target code must than make sure +that all target registers in the class returned by +@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are +saved. @var{after_prologue_epilogue_gen} indicates if prologues and +epilogues have already been generated. Note, even if you only return +true when @var{after_prologue_epilogue_gen} is false, you still are likely +to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET} +to reserve space for caller-saved target registers. +@end deftypefn + +@defmac POWI_MAX_MULTS +If defined, this macro is interpreted as a signed integer C expression +that specifies the maximum number of floating point multiplications +that should be emitted when expanding exponentiation by an integer +constant inline. When this value is defined, exponentiation requiring +more than this number of multiplications is implemented by calling the +system library's @code{pow}, @code{powf} or @code{powl} routines. +The default value places no upper bound on the multiplication count. +@end defmac + +@deftypefn Macro void TARGET_EXTRA_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc}) +This target hook should register any extra include files for the +target. The parameter @var{stdinc} indicates if normal include files +are present. The parameter @var{sysroot} is the system root directory. +The parameter @var{iprefix} is the prefix for the gcc directory. +@end deftypefn + +@deftypefn Macro void TARGET_EXTRA_PRE_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc}) +This target hook should register any extra include files for the +target before any standard headers. The parameter @var{stdinc} +indicates if normal include files are present. The parameter +@var{sysroot} is the system root directory. The parameter +@var{iprefix} is the prefix for the gcc directory. +@end deftypefn + +@deftypefn Macro void TARGET_OPTF (char *@var{path}) +This target hook should register special include paths for the target. +The parameter @var{path} is the include to register. On Darwin +systems, this is used for Framework includes, which have semantics +that are different from @option{-I}. +@end deftypefn + +@deftypefn {Target Hook} bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree @var{fndecl}) +This target hook returns @code{true} if it is safe to use a local alias +for a virtual function @var{fndecl} when constructing thunks, +@code{false} otherwise. By default, the hook returns @code{true} for all +functions, if a target supports aliases (i.e.@: defines +@code{ASM_OUTPUT_DEF}), @code{false} otherwise, +@end deftypefn + +@defmac TARGET_FORMAT_TYPES +If defined, this macro is the name of a global variable containing +target-specific format checking information for the @option{-Wformat} +option. The default is to have no target-specific format checks. +@end defmac + +@defmac TARGET_N_FORMAT_TYPES +If defined, this macro is the number of entries in +@code{TARGET_FORMAT_TYPES}. +@end defmac + +@deftypefn {Target Hook} bool TARGET_RELAXED_ORDERING +If set to @code{true}, means that the target's memory model does not +guarantee that loads which do not depend on one another will access +main memory in the order of the instruction stream; if ordering is +important, an explicit memory barrier must be used. This is true of +many recent processors which implement a policy of ``relaxed,'' +``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC, +and ia64. The default is @code{false}. +@end deftypefn + +@deftypefn {Target Hook} const char *TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN (tree @var{typelist}, tree @var{funcdecl}, tree @var{val}) +If defined, this macro returns the diagnostic message when it is +illegal to pass argument @var{val} to function @var{funcdecl} +with prototype @var{typelist}. +@end deftypefn + +@deftypefn {Target Hook} {const char *} TARGET_INVALID_CONVERSION (tree @var{fromtype}, tree @var{totype}) +If defined, this macro returns the diagnostic message when it is +invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL} +if validity should be determined by the front end. +@end deftypefn + +@deftypefn {Target Hook} {const char *} TARGET_INVALID_UNARY_OP (int @var{op}, tree @var{type}) +If defined, this macro returns the diagnostic message when it is +invalid to apply operation @var{op} (where unary plus is denoted by +@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL} +if validity should be determined by the front end. +@end deftypefn + +@deftypefn {Target Hook} {const char *} TARGET_INVALID_BINARY_OP (int @var{op}, tree @var{type1}, tree @var{type2}) +If defined, this macro returns the diagnostic message when it is +invalid to apply operation @var{op} to operands of types @var{type1} +and @var{type2}, or @code{NULL} if validity should be determined by +the front end. +@end deftypefn + +@defmac TARGET_USE_JCR_SECTION +This macro determines whether to use the JCR section to register Java +classes. By default, TARGET_USE_JCR_SECTION is defined to 1 if both +SUPPORTS_WEAK and TARGET_HAVE_NAMED_SECTIONS are true, else 0. +@end defmac + +@defmac OBJC_JBLEN +This macro determines the size of the objective C jump buffer for the +NeXT runtime. By default, OBJC_JBLEN is defined to an innocuous value. +@end defmac diff --git a/gcc-4.2.1-5666.3/gcc/doc/tree-ssa.texi b/gcc-4.2.1-5666.3/gcc/doc/tree-ssa.texi new file mode 100644 index 000000000..4ed5a33f2 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/tree-ssa.texi @@ -0,0 +1,1723 @@ +@c Copyright (c) 2004, 2005 Free Software Foundation, Inc. +@c Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@c --------------------------------------------------------------------- +@c Tree SSA +@c --------------------------------------------------------------------- + +@node Tree SSA +@chapter Analysis and Optimization of GIMPLE Trees +@cindex Tree SSA +@cindex Optimization infrastructure for GIMPLE + +GCC uses three main intermediate languages to represent the program +during compilation: GENERIC, GIMPLE and RTL@. GENERIC is a +language-independent representation generated by each front end. It +is used to serve as an interface between the parser and optimizer. +GENERIC is a common representation that is able to represent programs +written in all the languages supported by GCC@. + +GIMPLE and RTL are used to optimize the program. GIMPLE is used for +target and language independent optimizations (e.g., inlining, +constant propagation, tail call elimination, redundancy elimination, +etc). Much like GENERIC, GIMPLE is a language independent, tree based +representation. However, it differs from GENERIC in that the GIMPLE +grammar is more restrictive: expressions contain no more than 3 +operands (except function calls), it has no control flow structures +and expressions with side-effects are only allowed on the right hand +side of assignments. See the chapter describing GENERIC and GIMPLE +for more details. + +This chapter describes the data structures and functions used in the +GIMPLE optimizers (also known as ``tree optimizers'' or ``middle +end''). In particular, it focuses on all the macros, data structures, +functions and programming constructs needed to implement optimization +passes for GIMPLE@. + +@menu +* GENERIC:: A high-level language-independent representation. +* GIMPLE:: A lower-level factored tree representation. +* Annotations:: Attributes for statements and variables. +* Statement Operands:: Variables referenced by GIMPLE statements. +* SSA:: Static Single Assignment representation. +* Alias analysis:: Representing aliased loads and stores. +@end menu + +@node GENERIC +@section GENERIC +@cindex GENERIC + +The purpose of GENERIC is simply to provide a language-independent way of +representing an entire function in trees. To this end, it was necessary to +add a few new tree codes to the back end, but most everything was already +there. If you can express it with the codes in @code{gcc/tree.def}, it's +GENERIC@. + +Early on, there was a great deal of debate about how to think about +statements in a tree IL@. In GENERIC, a statement is defined as any +expression whose value, if any, is ignored. A statement will always +have @code{TREE_SIDE_EFFECTS} set (or it will be discarded), but a +non-statement expression may also have side effects. A +@code{CALL_EXPR}, for instance. + +It would be possible for some local optimizations to work on the +GENERIC form of a function; indeed, the adapted tree inliner works +fine on GENERIC, but the current compiler performs inlining after +lowering to GIMPLE (a restricted form described in the next section). +Indeed, currently the frontends perform this lowering before handing +off to @code{tree_rest_of_compilation}, but this seems inelegant. + +If necessary, a front end can use some language-dependent tree codes +in its GENERIC representation, so long as it provides a hook for +converting them to GIMPLE and doesn't expect them to work with any +(hypothetical) optimizers that run before the conversion to GIMPLE@. +The intermediate representation used while parsing C and C++ looks +very little like GENERIC, but the C and C++ gimplifier hooks are +perfectly happy to take it as input and spit out GIMPLE@. + +@node GIMPLE +@section GIMPLE +@cindex GIMPLE + +GIMPLE is a simplified subset of GENERIC for use in optimization. The +particular subset chosen (and the name) was heavily influenced by the +SIMPLE IL used by the McCAT compiler project at McGill University, +though we have made some different choices. For one thing, SIMPLE +doesn't support @code{goto}; a production compiler can't afford that +kind of restriction. + +GIMPLE retains much of the structure of the parse trees: lexical +scopes are represented as containers, rather than markers. However, +expressions are broken down into a 3-address form, using temporary +variables to hold intermediate values. Also, control structures are +lowered to gotos. + +In GIMPLE no container node is ever used for its value; if a +@code{COND_EXPR} or @code{BIND_EXPR} has a value, it is stored into a +temporary within the controlled blocks, and that temporary is used in +place of the container. + +The compiler pass which lowers GENERIC to GIMPLE is referred to as the +@samp{gimplifier}. The gimplifier works recursively, replacing complex +statements with sequences of simple statements. + +@c Currently, the only way to +@c tell whether or not an expression is in GIMPLE form is by recursively +@c examining it; in the future there will probably be a flag to help avoid +@c redundant work. FIXME FIXME + +@menu +* Interfaces:: +* Temporaries:: +* GIMPLE Expressions:: +* Statements:: +* GIMPLE Example:: +* Rough GIMPLE Grammar:: +@end menu + +@node Interfaces +@subsection Interfaces +@cindex gimplification + +The tree representation of a function is stored in +@code{DECL_SAVED_TREE}. It is lowered to GIMPLE by a call to +@code{gimplify_function_tree}. + +If a front end wants to include language-specific tree codes in the tree +representation which it provides to the back end, it must provide a +definition of @code{LANG_HOOKS_GIMPLIFY_EXPR} which knows how to +convert the front end trees to GIMPLE@. Usually such a hook will involve +much of the same code for expanding front end trees to RTL@. This function +can return fully lowered GIMPLE, or it can return GENERIC trees and let the +main gimplifier lower them the rest of the way; this is often simpler. +GIMPLE that is not fully lowered is known as ``high GIMPLE'' and +consists of the IL before the pass @code{pass_lower_cf}. High GIMPLE +still contains lexical scopes and nested expressions, while low GIMPLE +exposes all of the implicit jumps for control expressions like +@code{COND_EXPR}. + +The C and C++ front ends currently convert directly from front end +trees to GIMPLE, and hand that off to the back end rather than first +converting to GENERIC@. Their gimplifier hooks know about all the +@code{_STMT} nodes and how to convert them to GENERIC forms. There +was some work done on a genericization pass which would run first, but +the existence of @code{STMT_EXPR} meant that in order to convert all +of the C statements into GENERIC equivalents would involve walking the +entire tree anyway, so it was simpler to lower all the way. This +might change in the future if someone writes an optimization pass +which would work better with higher-level trees, but currently the +optimizers all expect GIMPLE@. + +A front end which wants to use the tree optimizers (and already has +some sort of whole-function tree representation) only needs to provide +a definition of @code{LANG_HOOKS_GIMPLIFY_EXPR}, call +@code{gimplify_function_tree} to lower to GIMPLE, and then hand off to +@code{tree_rest_of_compilation} to compile and output the function. + +You can tell the compiler to dump a C-like representation of the GIMPLE +form with the flag @option{-fdump-tree-gimple}. + +@node Temporaries +@subsection Temporaries +@cindex Temporaries + +When gimplification encounters a subexpression which is too complex, it +creates a new temporary variable to hold the value of the subexpression, +and adds a new statement to initialize it before the current statement. +These special temporaries are known as @samp{expression temporaries}, and are +allocated using @code{get_formal_tmp_var}. The compiler tries to +always evaluate identical expressions into the same temporary, to simplify +elimination of redundant calculations. + +We can only use expression temporaries when we know that it will not be +reevaluated before its value is used, and that it will not be otherwise +modified@footnote{These restrictions are derived from those in Morgan 4.8.}. +Other temporaries can be allocated using +@code{get_initialized_tmp_var} or @code{create_tmp_var}. + +Currently, an expression like @code{a = b + 5} is not reduced any +further. We tried converting it to something like +@smallexample + T1 = b + 5; + a = T1; +@end smallexample +but this bloated the representation for minimal benefit. However, a +variable which must live in memory cannot appear in an expression; its +value is explicitly loaded into a temporary first. Similarly, storing +the value of an expression to a memory variable goes through a +temporary. + +@node GIMPLE Expressions +@subsection Expressions +@cindex GIMPLE Expressions + +In general, expressions in GIMPLE consist of an operation and the +appropriate number of simple operands; these operands must either be a +GIMPLE rvalue (@code{is_gimple_val}), i.e.@: a constant or a register +variable. More complex operands are factored out into temporaries, so +that +@smallexample + a = b + c + d +@end smallexample +becomes +@smallexample + T1 = b + c; + a = T1 + d; +@end smallexample + +The same rule holds for arguments to a @code{CALL_EXPR}. + +The target of an assignment is usually a variable, but can also be an +@code{INDIRECT_REF} or a compound lvalue as described below. + +@menu +* Compound Expressions:: +* Compound Lvalues:: +* Conditional Expressions:: +* Logical Operators:: +@end menu + +@node Compound Expressions +@subsubsection Compound Expressions +@cindex Compound Expressions + +The left-hand side of a C comma expression is simply moved into a separate +statement. + +@node Compound Lvalues +@subsubsection Compound Lvalues +@cindex Compound Lvalues + +Currently compound lvalues involving array and structure field references +are not broken down; an expression like @code{a.b[2] = 42} is not reduced +any further (though complex array subscripts are). This restriction is a +workaround for limitations in later optimizers; if we were to convert this +to + +@smallexample + T1 = &a.b; + T1[2] = 42; +@end smallexample + +alias analysis would not remember that the reference to @code{T1[2]} came +by way of @code{a.b}, so it would think that the assignment could alias +another member of @code{a}; this broke @code{struct-alias-1.c}. Future +optimizer improvements may make this limitation unnecessary. + +@node Conditional Expressions +@subsubsection Conditional Expressions +@cindex Conditional Expressions + +A C @code{?:} expression is converted into an @code{if} statement with +each branch assigning to the same temporary. So, + +@smallexample + a = b ? c : d; +@end smallexample +becomes +@smallexample + if (b) + T1 = c; + else + T1 = d; + a = T1; +@end smallexample + +Tree level if-conversion pass re-introduces @code{?:} expression, if appropriate. +It is used to vectorize loops with conditions using vector conditional operations. + +Note that in GIMPLE, @code{if} statements are also represented using +@code{COND_EXPR}, as described below. + +@node Logical Operators +@subsubsection Logical Operators +@cindex Logical Operators + +Except when they appear in the condition operand of a @code{COND_EXPR}, +logical `and' and `or' operators are simplified as follows: +@code{a = b && c} becomes + +@smallexample + T1 = (bool)b; + if (T1) + T1 = (bool)c; + a = T1; +@end smallexample + +Note that @code{T1} in this example cannot be an expression temporary, +because it has two different assignments. + +@node Statements +@subsection Statements +@cindex Statements + +Most statements will be assignment statements, represented by +@code{MODIFY_EXPR}. A @code{CALL_EXPR} whose value is ignored can +also be a statement. No other C expressions can appear at statement level; +a reference to a volatile object is converted into a @code{MODIFY_EXPR}. +In GIMPLE form, type of @code{MODIFY_EXPR} is not meaningful. Instead, use type +of LHS or RHS@. + +There are also several varieties of complex statements. + +@menu +* Blocks:: +* Statement Sequences:: +* Empty Statements:: +* Loops:: +* Selection Statements:: +* Jumps:: +* Cleanups:: +* GIMPLE Exception Handling:: +@end menu + +@node Blocks +@subsubsection Blocks +@cindex Blocks + +Block scopes and the variables they declare in GENERIC and GIMPLE are +expressed using the @code{BIND_EXPR} code, which in previous versions of +GCC was primarily used for the C statement-expression extension. + +Variables in a block are collected into @code{BIND_EXPR_VARS} in +declaration order. Any runtime initialization is moved out of +@code{DECL_INITIAL} and into a statement in the controlled block. When +gimplifying from C or C++, this initialization replaces the +@code{DECL_STMT}. + +Variable-length arrays (VLAs) complicate this process, as their size often +refers to variables initialized earlier in the block. To handle this, we +currently split the block at that point, and move the VLA into a new, inner +@code{BIND_EXPR}. This strategy may change in the future. + +@code{DECL_SAVED_TREE} for a GIMPLE function will always be a +@code{BIND_EXPR} which contains declarations for the temporary variables +used in the function. + +A C++ program will usually contain more @code{BIND_EXPR}s than there are +syntactic blocks in the source code, since several C++ constructs have +implicit scopes associated with them. On the other hand, although the C++ +front end uses pseudo-scopes to handle cleanups for objects with +destructors, these don't translate into the GIMPLE form; multiple +declarations at the same level use the same @code{BIND_EXPR}. + +@node Statement Sequences +@subsubsection Statement Sequences +@cindex Statement Sequences + +Multiple statements at the same nesting level are collected into a +@code{STATEMENT_LIST}. Statement lists are modified and traversed +using the interface in @samp{tree-iterator.h}. + +@node Empty Statements +@subsubsection Empty Statements +@cindex Empty Statements + +Whenever possible, statements with no effect are discarded. But if they +are nested within another construct which cannot be discarded for some +reason, they are instead replaced with an empty statement, generated by +@code{build_empty_stmt}. Initially, all empty statements were shared, +after the pattern of the Java front end, but this caused a lot of trouble in +practice. + +An empty statement is represented as @code{(void)0}. + +@node Loops +@subsubsection Loops +@cindex Loops + +At one time loops were expressed in GIMPLE using @code{LOOP_EXPR}, but +now they are lowered to explicit gotos. + +@node Selection Statements +@subsubsection Selection Statements +@cindex Selection Statements + +A simple selection statement, such as the C @code{if} statement, is +expressed in GIMPLE using a void @code{COND_EXPR}. If only one branch is +used, the other is filled with an empty statement. + +Normally, the condition expression is reduced to a simple comparison. If +it is a shortcut (@code{&&} or @code{||}) expression, however, we try to +break up the @code{if} into multiple @code{if}s so that the implied shortcut +is taken directly, much like the transformation done by @code{do_jump} in +the RTL expander. + +A @code{SWITCH_EXPR} in GIMPLE contains the condition and a +@code{TREE_VEC} of @code{CASE_LABEL_EXPR}s describing the case values +and corresponding @code{LABEL_DECL}s to jump to. The body of the +@code{switch} is moved after the @code{SWITCH_EXPR}. + +@node Jumps +@subsubsection Jumps +@cindex Jumps + +Other jumps are expressed by either @code{GOTO_EXPR} or @code{RETURN_EXPR}. + +The operand of a @code{GOTO_EXPR} must be either a label or a variable +containing the address to jump to. + +The operand of a @code{RETURN_EXPR} is either @code{NULL_TREE}, +@code{RESULT_DECL}, or a @code{MODIFY_EXPR} which sets the return value. It +would be nice to move the @code{MODIFY_EXPR} into a separate statement, but the +special return semantics in @code{expand_return} make that difficult. It may +still happen in the future, perhaps by moving most of that logic into +@code{expand_assignment}. + +@node Cleanups +@subsubsection Cleanups +@cindex Cleanups + +Destructors for local C++ objects and similar dynamic cleanups are +represented in GIMPLE by a @code{TRY_FINALLY_EXPR}. +@code{TRY_FINALLY_EXPR} has two operands, both of which are a sequence +of statements to execute. The first sequence is executed. When it +completes the second sequence is executed. + +The first sequence may complete in the following ways: + +@enumerate + +@item Execute the last statement in the sequence and fall off the +end. + +@item Execute a goto statement (@code{GOTO_EXPR}) to an ordinary +label outside the sequence. + +@item Execute a return statement (@code{RETURN_EXPR}). + +@item Throw an exception. This is currently not explicitly represented in +GIMPLE. + +@end enumerate + +The second sequence is not executed if the first sequence completes by +calling @code{setjmp} or @code{exit} or any other function that does +not return. The second sequence is also not executed if the first +sequence completes via a non-local goto or a computed goto (in general +the compiler does not know whether such a goto statement exits the +first sequence or not, so we assume that it doesn't). + +After the second sequence is executed, if it completes normally by +falling off the end, execution continues wherever the first sequence +would have continued, by falling off the end, or doing a goto, etc. + +@code{TRY_FINALLY_EXPR} complicates the flow graph, since the cleanup +needs to appear on every edge out of the controlled block; this +reduces the freedom to move code across these edges. Therefore, the +EH lowering pass which runs before most of the optimization passes +eliminates these expressions by explicitly adding the cleanup to each +edge. Rethrowing the exception is represented using @code{RESX_EXPR}. + + +@node GIMPLE Exception Handling +@subsubsection Exception Handling +@cindex GIMPLE Exception Handling + +Other exception handling constructs are represented using +@code{TRY_CATCH_EXPR}. @code{TRY_CATCH_EXPR} has two operands. The +first operand is a sequence of statements to execute. If executing +these statements does not throw an exception, then the second operand +is ignored. Otherwise, if an exception is thrown, then the second +operand of the @code{TRY_CATCH_EXPR} is checked. The second operand +may have the following forms: + +@enumerate + +@item A sequence of statements to execute. When an exception occurs, +these statements are executed, and then the exception is rethrown. + +@item A sequence of @code{CATCH_EXPR} expressions. Each @code{CATCH_EXPR} +has a list of applicable exception types and handler code. If the +thrown exception matches one of the caught types, the associated +handler code is executed. If the handler code falls off the bottom, +execution continues after the original @code{TRY_CATCH_EXPR}. + +@item An @code{EH_FILTER_EXPR} expression. This has a list of +permitted exception types, and code to handle a match failure. If the +thrown exception does not match one of the allowed types, the +associated match failure code is executed. If the thrown exception +does match, it continues unwinding the stack looking for the next +handler. + +@end enumerate + +Currently throwing an exception is not directly represented in GIMPLE, +since it is implemented by calling a function. At some point in the future +we will want to add some way to express that the call will throw an +exception of a known type. + +Just before running the optimizers, the compiler lowers the high-level +EH constructs above into a set of @samp{goto}s, magic labels, and EH +regions. Continuing to unwind at the end of a cleanup is represented +with a @code{RESX_EXPR}. + +@node GIMPLE Example +@subsection GIMPLE Example +@cindex GIMPLE Example + +@smallexample +struct A @{ A(); ~A(); @}; + +int i; +int g(); +void f() +@{ + A a; + int j = (--i, i ? 0 : 1); + + for (int x = 42; x > 0; --x) + @{ + i += g()*4 + 32; + @} +@} +@end smallexample + +becomes + +@smallexample +void f() +@{ + int i.0; + int T.1; + int iftmp.2; + int T.3; + int T.4; + int T.5; + int T.6; + + @{ + struct A a; + int j; + + __comp_ctor (&a); + try + @{ + i.0 = i; + T.1 = i.0 - 1; + i = T.1; + i.0 = i; + if (i.0 == 0) + iftmp.2 = 1; + else + iftmp.2 = 0; + j = iftmp.2; + @{ + int x; + + x = 42; + goto test; + loop:; + + T.3 = g (); + T.4 = T.3 * 4; + i.0 = i; + T.5 = T.4 + i.0; + T.6 = T.5 + 32; + i = T.6; + x = x - 1; + + test:; + if (x > 0) + goto loop; + else + goto break_; + break_:; + @} + @} + finally + @{ + __comp_dtor (&a); + @} + @} +@} +@end smallexample + +@node Rough GIMPLE Grammar +@subsection Rough GIMPLE Grammar +@cindex Rough GIMPLE Grammar + +@smallexample + function : FUNCTION_DECL + DECL_SAVED_TREE -> compound-stmt + + compound-stmt: STATEMENT_LIST + members -> stmt + + stmt : block + | if-stmt + | switch-stmt + | goto-stmt + | return-stmt + | resx-stmt + | label-stmt + | try-stmt + | modify-stmt + | call-stmt + + block : BIND_EXPR + BIND_EXPR_VARS -> chain of DECLs + BIND_EXPR_BLOCK -> BLOCK + BIND_EXPR_BODY -> compound-stmt + + if-stmt : COND_EXPR + op0 -> condition + op1 -> compound-stmt + op2 -> compound-stmt + + switch-stmt : SWITCH_EXPR + op0 -> val + op1 -> NULL + op2 -> TREE_VEC of CASE_LABEL_EXPRs + The CASE_LABEL_EXPRs are sorted by CASE_LOW, + and default is last. + + goto-stmt : GOTO_EXPR + op0 -> LABEL_DECL | val + + return-stmt : RETURN_EXPR + op0 -> return-value + + return-value : NULL + | RESULT_DECL + | MODIFY_EXPR + op0 -> RESULT_DECL + op1 -> lhs + + resx-stmt : RESX_EXPR + + label-stmt : LABEL_EXPR + op0 -> LABEL_DECL + + try-stmt : TRY_CATCH_EXPR + op0 -> compound-stmt + op1 -> handler + | TRY_FINALLY_EXPR + op0 -> compound-stmt + op1 -> compound-stmt + + handler : catch-seq + | EH_FILTER_EXPR + | compound-stmt + + catch-seq : STATEMENT_LIST + members -> CATCH_EXPR + + modify-stmt : MODIFY_EXPR + op0 -> lhs + op1 -> rhs + + call-stmt : CALL_EXPR + op0 -> val | OBJ_TYPE_REF + op1 -> call-arg-list + + call-arg-list: TREE_LIST + members -> lhs | CONST + + addr-expr-arg: ID + | compref + + addressable : addr-expr-arg + | indirectref + + with-size-arg: addressable + | call-stmt + + indirectref : INDIRECT_REF + op0 -> val + + lhs : addressable + | bitfieldref + | WITH_SIZE_EXPR + op0 -> with-size-arg + op1 -> val + + min-lval : ID + | indirectref + + bitfieldref : BIT_FIELD_REF + op0 -> inner-compref + op1 -> CONST + op2 -> var + + compref : inner-compref + | TARGET_MEM_REF + op0 -> ID + op1 -> val + op2 -> val + op3 -> CONST + op4 -> CONST + | REALPART_EXPR + op0 -> inner-compref + | IMAGPART_EXPR + op0 -> inner-compref + + inner-compref: min-lval + | COMPONENT_REF + op0 -> inner-compref + op1 -> FIELD_DECL + op2 -> val + | ARRAY_REF + op0 -> inner-compref + op1 -> val + op2 -> val + op3 -> val + | ARRAY_RANGE_REF + op0 -> inner-compref + op1 -> val + op2 -> val + op3 -> val + | VIEW_CONVERT_EXPR + op0 -> inner-compref + + condition : val + | RELOP + op0 -> val + op1 -> val + + val : ID + | CONST + + rhs : lhs + | CONST + | call-stmt + | ADDR_EXPR + op0 -> addr-expr-arg + | UNOP + op0 -> val + | BINOP + op0 -> val + op1 -> val + | RELOP + op0 -> val + op1 -> val + | COND_EXPR + op0 -> condition + op1 -> val + op2 -> val +@end smallexample + +@node Annotations +@section Annotations +@cindex annotations + +The optimizers need to associate attributes with statements and +variables during the optimization process. For instance, we need to +know what basic block a statement belongs to or whether a variable +has aliases. All these attributes are stored in data structures +called annotations which are then linked to the field @code{ann} in +@code{struct tree_common}. + +Presently, we define annotations for statements (@code{stmt_ann_t}), +variables (@code{var_ann_t}) and SSA names (@code{ssa_name_ann_t}). +Annotations are defined and documented in @file{tree-flow.h}. + + +@node Statement Operands +@section Statement Operands +@cindex operands +@cindex virtual operands +@cindex real operands +@findex update_stmt + +Almost every GIMPLE statement will contain a reference to a variable +or memory location. Since statements come in different shapes and +sizes, their operands are going to be located at various spots inside +the statement's tree. To facilitate access to the statement's +operands, they are organized into lists associated inside each +statement's annotation. Each element in an operand list is a pointer +to a @code{VAR_DECL}, @code{PARM_DECL} or @code{SSA_NAME} tree node. +This provides a very convenient way of examining and replacing +operands. + +Data flow analysis and optimization is done on all tree nodes +representing variables. Any node for which @code{SSA_VAR_P} returns +nonzero is considered when scanning statement operands. However, not +all @code{SSA_VAR_P} variables are processed in the same way. For the +purposes of optimization, we need to distinguish between references to +local scalar variables and references to globals, statics, structures, +arrays, aliased variables, etc. The reason is simple, the compiler +can gather complete data flow information for a local scalar. On the +other hand, a global variable may be modified by a function call, it +may not be possible to keep track of all the elements of an array or +the fields of a structure, etc. + +The operand scanner gathers two kinds of operands: @dfn{real} and +@dfn{virtual}. An operand for which @code{is_gimple_reg} returns true +is considered real, otherwise it is a virtual operand. We also +distinguish between uses and definitions. An operand is used if its +value is loaded by the statement (e.g., the operand at the RHS of an +assignment). If the statement assigns a new value to the operand, the +operand is considered a definition (e.g., the operand at the LHS of +an assignment). + +Virtual and real operands also have very different data flow +properties. Real operands are unambiguous references to the +full object that they represent. For instance, given + +@smallexample +@{ + int a, b; + a = b +@} +@end smallexample + +Since @code{a} and @code{b} are non-aliased locals, the statement +@code{a = b} will have one real definition and one real use because +variable @code{b} is completely modified with the contents of +variable @code{a}. Real definition are also known as @dfn{killing +definitions}. Similarly, the use of @code{a} reads all its bits. + +In contrast, virtual operands are used with variables that can have +a partial or ambiguous reference. This includes structures, arrays, +globals, and aliased variables. In these cases, we have two types of +definitions. For globals, structures, and arrays, we can determine from +a statement whether a variable of these types has a killing definition. +If the variable does, then the statement is marked as having a +@dfn{must definition} of that variable. However, if a statement is only +defining a part of the variable (i.e.@: a field in a structure), or if we +know that a statement might define the variable but we cannot say for sure, +then we mark that statement as having a @dfn{may definition}. For +instance, given + +@smallexample +@{ + int a, b, *p; + + if (...) + p = &a; + else + p = &b; + *p = 5; + return *p; +@} +@end smallexample + +The assignment @code{*p = 5} may be a definition of @code{a} or +@code{b}. If we cannot determine statically where @code{p} is +pointing to at the time of the store operation, we create virtual +definitions to mark that statement as a potential definition site for +@code{a} and @code{b}. Memory loads are similarly marked with virtual +use operands. Virtual operands are shown in tree dumps right before +the statement that contains them. To request a tree dump with virtual +operands, use the @option{-vops} option to @option{-fdump-tree}: + +@smallexample +@{ + int a, b, *p; + + if (...) + p = &a; + else + p = &b; + # a = V_MAY_DEF <a> + # b = V_MAY_DEF <b> + *p = 5; + + # VUSE <a> + # VUSE <b> + return *p; +@} +@end smallexample + +Notice that @code{V_MAY_DEF} operands have two copies of the referenced +variable. This indicates that this is not a killing definition of +that variable. In this case we refer to it as a @dfn{may definition} +or @dfn{aliased store}. The presence of the second copy of the +variable in the @code{V_MAY_DEF} operand will become important when the +function is converted into SSA form. This will be used to link all +the non-killing definitions to prevent optimizations from making +incorrect assumptions about them. + +Operands are updated as soon as the statement is finished via a call +to @code{update_stmt}. If statement elements are changed via +@code{SET_USE} or @code{SET_DEF}, then no further action is required +(i.e., those macros take care of updating the statement). If changes +are made by manipulating the statement's tree directly, then a call +must be made to @code{update_stmt} when complete. Calling one of the +@code{bsi_insert} routines or @code{bsi_replace} performs an implicit +call to @code{update_stmt}. + +@subsection Operand Iterators And Access Routines +@cindex Operand Iterators +@cindex Operand Access Routines + +Operands are collected by @file{tree-ssa-operands.c}. They are stored +inside each statement's annotation and can be accessed through either the +operand iterators or an access routine. + +The following access routines are available for examining operands: + +@enumerate +@item @code{SINGLE_SSA_@{USE,DEF,TREE@}_OPERAND}: These accessors will return +NULL unless there is exactly one operand matching the specified flags. If +there is exactly one operand, the operand is returned as either a @code{tree}, +@code{def_operand_p}, or @code{use_operand_p}. + +@smallexample +tree t = SINGLE_SSA_TREE_OPERAND (stmt, flags); +use_operand_p u = SINGLE_SSA_USE_OPERAND (stmt, SSA_ALL_VIRTUAL_USES); +def_operand_p d = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_ALL_DEFS); +@end smallexample + +@item @code{ZERO_SSA_OPERANDS}: This macro returns true if there are no +operands matching the specified flags. + +@smallexample +if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) + return; +@end smallexample + +@item @code{NUM_SSA_OPERANDS}: This macro Returns the number of operands +matching 'flags'. This actually executes a loop to perform the count, so +only use this if it is really needed. + +@smallexample +int count = NUM_SSA_OPERANDS (stmt, flags) +@end smallexample +@end enumerate + + +If you wish to iterate over some or all operands, use the +@code{FOR_EACH_SSA_@{USE,DEF,TREE@}_OPERAND} iterator. For example, to print +all the operands for a statement: + +@smallexample +void +print_ops (tree stmt) +@{ + ssa_op_iter; + tree var; + + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_OPERANDS) + print_generic_expr (stderr, var, TDF_SLIM); +@} +@end smallexample + + +How to choose the appropriate iterator: + +@enumerate +@item Determine whether you are need to see the operand pointers, or just the + trees, and choose the appropriate macro: + +@smallexample +Need Macro: +---- ------- +use_operand_p FOR_EACH_SSA_USE_OPERAND +def_operand_p FOR_EACH_SSA_DEF_OPERAND +tree FOR_EACH_SSA_TREE_OPERAND +@end smallexample + +@item You need to declare a variable of the type you are interested + in, and an ssa_op_iter structure which serves as the loop + controlling variable. + +@item Determine which operands you wish to use, and specify the flags of + those you are interested in. They are documented in + @file{tree-ssa-operands.h}: + +@smallexample +#define SSA_OP_USE 0x01 /* @r{Real USE operands.} */ +#define SSA_OP_DEF 0x02 /* @r{Real DEF operands.} */ +#define SSA_OP_VUSE 0x04 /* @r{VUSE operands.} */ +#define SSA_OP_VMAYUSE 0x08 /* @r{USE portion of V_MAY_DEFS.} */ +#define SSA_OP_VMAYDEF 0x10 /* @r{DEF portion of V_MAY_DEFS.} */ +#define SSA_OP_VMUSTDEF 0x20 /* @r{V_MUST_DEF definitions.} */ + +/* @r{These are commonly grouped operand flags.} */ +#define SSA_OP_VIRTUAL_USES (SSA_OP_VUSE | SSA_OP_VMAYUSE) +#define SSA_OP_VIRTUAL_DEFS (SSA_OP_VMAYDEF | SSA_OP_VMUSTDEF) +#define SSA_OP_ALL_USES (SSA_OP_VIRTUAL_USES | SSA_OP_USE) +#define SSA_OP_ALL_DEFS (SSA_OP_VIRTUAL_DEFS | SSA_OP_DEF) +#define SSA_OP_ALL_OPERANDS (SSA_OP_ALL_USES | SSA_OP_ALL_DEFS) +@end smallexample +@end enumerate + +So if you want to look at the use pointers for all the @code{USE} and +@code{VUSE} operands, you would do something like: + +@smallexample + use_operand_p use_p; + ssa_op_iter iter; + + FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, (SSA_OP_USE | SSA_OP_VUSE)) + @{ + process_use_ptr (use_p); + @} +@end smallexample + +The @code{TREE} macro is basically the same as the @code{USE} and +@code{DEF} macros, only with the use or def dereferenced via +@code{USE_FROM_PTR (use_p)} and @code{DEF_FROM_PTR (def_p)}. Since we +aren't using operand pointers, use and defs flags can be mixed. + +@smallexample + tree var; + ssa_op_iter iter; + + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_VUSE | SSA_OP_VMUSTDEF) + @{ + print_generic_expr (stderr, var, TDF_SLIM); + @} +@end smallexample + +@code{V_MAY_DEF}s are broken into two flags, one for the +@code{DEF} portion (@code{SSA_OP_VMAYDEF}) and one for the USE portion +(@code{SSA_OP_VMAYUSE}). If all you want to look at are the +@code{V_MAY_DEF}s together, there is a fourth iterator macro for this, +which returns both a def_operand_p and a use_operand_p for each +@code{V_MAY_DEF} in the statement. Note that you don't need any flags for +this one. + +@smallexample + use_operand_p use_p; + def_operand_p def_p; + ssa_op_iter iter; + + FOR_EACH_SSA_MAYDEF_OPERAND (def_p, use_p, stmt, iter) + @{ + my_code; + @} +@end smallexample + +@code{V_MUST_DEF}s are broken into two flags, one for the +@code{DEF} portion (@code{SSA_OP_VMUSTDEF}) and one for the kill portion +(@code{SSA_OP_VMUSTKILL}). If all you want to look at are the +@code{V_MUST_DEF}s together, there is a fourth iterator macro for this, +which returns both a def_operand_p and a use_operand_p for each +@code{V_MUST_DEF} in the statement. Note that you don't need any flags for +this one. + +@smallexample + use_operand_p kill_p; + def_operand_p def_p; + ssa_op_iter iter; + + FOR_EACH_SSA_MUSTDEF_OPERAND (def_p, kill_p, stmt, iter) + @{ + my_code; + @} +@end smallexample + + +There are many examples in the code as well, as well as the +documentation in @file{tree-ssa-operands.h}. + +There are also a couple of variants on the stmt iterators regarding PHI +nodes. + +@code{FOR_EACH_PHI_ARG} Works exactly like +@code{FOR_EACH_SSA_USE_OPERAND}, except it works over @code{PHI} arguments +instead of statement operands. + +@smallexample +/* Look at every virtual PHI use. */ +FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_VIRTUAL_USES) +@{ + my_code; +@} + +/* Look at every real PHI use. */ +FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_USES) + my_code; + +/* Look at every every PHI use. */ +FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_ALL_USES) + my_code; +@end smallexample + +@code{FOR_EACH_PHI_OR_STMT_@{USE,DEF@}} works exactly like +@code{FOR_EACH_SSA_@{USE,DEF@}_OPERAND}, except it will function on +either a statement or a @code{PHI} node. These should be used when it is +appropriate but they are not quite as efficient as the individual +@code{FOR_EACH_PHI} and @code{FOR_EACH_SSA} routines. + +@smallexample +FOR_EACH_PHI_OR_STMT_USE (use_operand_p, stmt, iter, flags) + @{ + my_code; + @} + +FOR_EACH_PHI_OR_STMT_DEF (def_operand_p, phi, iter, flags) + @{ + my_code; + @} +@end smallexample + +@subsection Immediate Uses +@cindex Immediate Uses + +Immediate use information is now always available. Using the immediate use +iterators, you may examine every use of any @code{SSA_NAME}. For instance, +to change each use of @code{ssa_var} to @code{ssa_var2} and call fold_stmt on +each stmt after that is done: + +@smallexample + use_operand_p imm_use_p; + imm_use_iterator iterator; + tree ssa_var, stmt; + + + FOR_EACH_IMM_USE_STMT (stmt, iterator, ssa_var) + @{ + FOR_EACH_IMM_USE_ON_STMT (imm_use_p, iterator) + SET_USE (imm_use_p, ssa_var_2); + fold_stmt (stmt); + @} +@end smallexample + +There are 2 iterators which can be used. @code{FOR_EACH_IMM_USE_FAST} is +used when the immediate uses are not changed, i.e., you are looking at the +uses, but not setting them. + +If they do get changed, then care must be taken that things are not changed +under the iterators, so use the @code{FOR_EACH_IMM_USE_STMT} and +@code{FOR_EACH_IMM_USE_ON_STMT} iterators. They attempt to preserve the +sanity of the use list by moving all the uses for a statement into +a controlled position, and then iterating over those uses. Then the +optimization can manipulate the stmt when all the uses have been +processed. This is a little slower than the FAST version since it adds a +placeholder element and must sort through the list a bit for each statement. +This placeholder element must be also be removed if the loop is +terminated early. The macro @code{BREAK_FROM_IMM_USE_SAFE} is provided +to do this : + +@smallexample + FOR_EACH_IMM_USE_STMT (stmt, iterator, ssa_var) + @{ + if (stmt == last_stmt) + BREAK_FROM_SAFE_IMM_USE (iter); + + FOR_EACH_IMM_USE_ON_STMT (imm_use_p, iterator) + SET_USE (imm_use_p, ssa_var_2); + fold_stmt (stmt); + @} +@end smallexample + +There are checks in @code{verify_ssa} which verify that the immediate use list +is up to date, as well as checking that an optimization didn't break from the +loop without using this macro. It is safe to simply 'break'; from a +@code{FOR_EACH_IMM_USE_FAST} traverse. + +Some useful functions and macros: +@enumerate +@item @code{has_zero_uses (ssa_var)} : Returns true if there are no uses of +@code{ssa_var}. +@item @code{has_single_use (ssa_var)} : Returns true if there is only a +single use of @code{ssa_var}. +@item @code{single_imm_use (ssa_var, use_operand_p *ptr, tree *stmt)} : +Returns true if there is only a single use of @code{ssa_var}, and also returns +the use pointer and statement it occurs in in the second and third parameters. +@item @code{num_imm_uses (ssa_var)} : Returns the number of immediate uses of +@code{ssa_var}. It is better not to use this if possible since it simply +utilizes a loop to count the uses. +@item @code{PHI_ARG_INDEX_FROM_USE (use_p)} : Given a use within a @code{PHI} +node, return the index number for the use. An assert is triggered if the use +isn't located in a @code{PHI} node. +@item @code{USE_STMT (use_p)} : Return the statement a use occurs in. +@end enumerate + +Note that uses are not put into an immediate use list until their statement is +actually inserted into the instruction stream via a @code{bsi_*} routine. + +It is also still possible to utilize lazy updating of statements, but this +should be used only when absolutely required. Both alias analysis and the +dominator optimizations currently do this. + +When lazy updating is being used, the immediate use information is out of date +and cannot be used reliably. Lazy updating is achieved by simply marking +statements modified via calls to @code{mark_stmt_modified} instead of +@code{update_stmt}. When lazy updating is no longer required, all the +modified statements must have @code{update_stmt} called in order to bring them +up to date. This must be done before the optimization is finished, or +@code{verify_ssa} will trigger an abort. + +This is done with a simple loop over the instruction stream: +@smallexample + block_stmt_iterator bsi; + basic_block bb; + FOR_EACH_BB (bb) + @{ + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + update_stmt_if_modified (bsi_stmt (bsi)); + @} +@end smallexample + +@node SSA +@section Static Single Assignment +@cindex SSA +@cindex static single assignment + +Most of the tree optimizers rely on the data flow information provided +by the Static Single Assignment (SSA) form. We implement the SSA form +as described in @cite{R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and +K. Zadeck. Efficiently Computing Static Single Assignment Form and the +Control Dependence Graph. ACM Transactions on Programming Languages +and Systems, 13(4):451-490, October 1991}. + +The SSA form is based on the premise that program variables are +assigned in exactly one location in the program. Multiple assignments +to the same variable create new versions of that variable. Naturally, +actual programs are seldom in SSA form initially because variables +tend to be assigned multiple times. The compiler modifies the program +representation so that every time a variable is assigned in the code, +a new version of the variable is created. Different versions of the +same variable are distinguished by subscripting the variable name with +its version number. Variables used in the right-hand side of +expressions are renamed so that their version number matches that of +the most recent assignment. + +We represent variable versions using @code{SSA_NAME} nodes. The +renaming process in @file{tree-ssa.c} wraps every real and +virtual operand with an @code{SSA_NAME} node which contains +the version number and the statement that created the +@code{SSA_NAME}. Only definitions and virtual definitions may +create new @code{SSA_NAME} nodes. + +Sometimes, flow of control makes it impossible to determine what is the +most recent version of a variable. In these cases, the compiler +inserts an artificial definition for that variable called +@dfn{PHI function} or @dfn{PHI node}. This new definition merges +all the incoming versions of the variable to create a new name +for it. For instance, + +@smallexample +if (...) + a_1 = 5; +else if (...) + a_2 = 2; +else + a_3 = 13; + +# a_4 = PHI <a_1, a_2, a_3> +return a_4; +@end smallexample + +Since it is not possible to determine which of the three branches +will be taken at runtime, we don't know which of @code{a_1}, +@code{a_2} or @code{a_3} to use at the return statement. So, the +SSA renamer creates a new version @code{a_4} which is assigned +the result of ``merging'' @code{a_1}, @code{a_2} and @code{a_3}. +Hence, PHI nodes mean ``one of these operands. I don't know +which''. + +The following macros can be used to examine PHI nodes + +@defmac PHI_RESULT (@var{phi}) +Returns the @code{SSA_NAME} created by PHI node @var{phi} (i.e., +@var{phi}'s LHS)@. +@end defmac + +@defmac PHI_NUM_ARGS (@var{phi}) +Returns the number of arguments in @var{phi}. This number is exactly +the number of incoming edges to the basic block holding @var{phi}@. +@end defmac + +@defmac PHI_ARG_ELT (@var{phi}, @var{i}) +Returns a tuple representing the @var{i}th argument of @var{phi}@. +Each element of this tuple contains an @code{SSA_NAME} @var{var} and +the incoming edge through which @var{var} flows. +@end defmac + +@defmac PHI_ARG_EDGE (@var{phi}, @var{i}) +Returns the incoming edge for the @var{i}th argument of @var{phi}. +@end defmac + +@defmac PHI_ARG_DEF (@var{phi}, @var{i}) +Returns the @code{SSA_NAME} for the @var{i}th argument of @var{phi}. +@end defmac + + +@subsection Preserving the SSA form +@findex update_ssa +@cindex preserving SSA form +Some optimization passes make changes to the function that +invalidate the SSA property. This can happen when a pass has +added new symbols or changed the program so that variables that +were previously aliased aren't anymore. Whenever something like this +happens, the affected symbols must be renamed into SSA form again. +Transformations that emit new code or replicate existing statements +will also need to update the SSA form@. + +Since GCC implements two different SSA forms for register and virtual +variables, keeping the SSA form up to date depends on whether you are +updating register or virtual names. In both cases, the general idea +behind incremental SSA updates is similar: when new SSA names are +created, they typically are meant to replace other existing names in +the program@. + +For instance, given the following code: + +@smallexample + 1 L0: + 2 x_1 = PHI (0, x_5) + 3 if (x_1 < 10) + 4 if (x_1 > 7) + 5 y_2 = 0 + 6 else + 7 y_3 = x_1 + x_7 + 8 endif + 9 x_5 = x_1 + 1 + 10 goto L0; + 11 endif +@end smallexample + +Suppose that we insert new names @code{x_10} and @code{x_11} (lines +@code{4} and @code{8})@. + +@smallexample + 1 L0: + 2 x_1 = PHI (0, x_5) + 3 if (x_1 < 10) + 4 x_10 = ... + 5 if (x_1 > 7) + 6 y_2 = 0 + 7 else + 8 x_11 = ... + 9 y_3 = x_1 + x_7 + 10 endif + 11 x_5 = x_1 + 1 + 12 goto L0; + 13 endif +@end smallexample + +We want to replace all the uses of @code{x_1} with the new definitions +of @code{x_10} and @code{x_11}. Note that the only uses that should +be replaced are those at lines @code{5}, @code{9} and @code{11}. +Also, the use of @code{x_7} at line @code{9} should @emph{not} be +replaced (this is why we cannot just mark symbol @code{x} for +renaming)@. + +Additionally, we may need to insert a PHI node at line @code{11} +because that is a merge point for @code{x_10} and @code{x_11}. So the +use of @code{x_1} at line @code{11} will be replaced with the new PHI +node. The insertion of PHI nodes is optional. They are not strictly +necessary to preserve the SSA form, and depending on what the caller +inserted, they may not even be useful for the optimizers@. + +Updating the SSA form is a two step process. First, the pass has to +identify which names need to be updated and/or which symbols need to +be renamed into SSA form for the first time. When new names are +introduced to replace existing names in the program, the mapping +between the old and the new names are registered by calling +@code{register_new_name_mapping} (note that if your pass creates new +code by duplicating basic blocks, the call to @code{tree_duplicate_bb} +will set up the necessary mappings automatically). On the other hand, +if your pass exposes a new symbol that should be put in SSA form for +the first time, the new symbol should be registered with +@code{mark_sym_for_renaming}. + +After the replacement mappings have been registered and new symbols +marked for renaming, a call to @code{update_ssa} makes the registered +changes. This can be done with an explicit call or by creating +@code{TODO} flags in the @code{tree_opt_pass} structure for your pass. +There are several @code{TODO} flags that control the behavior of +@code{update_ssa}: + +@itemize @bullet +@item @code{TODO_update_ssa}. Update the SSA form inserting PHI nodes + for newly exposed symbols and virtual names marked for updating. + When updating real names, only insert PHI nodes for a real name + @code{O_j} in blocks reached by all the new and old definitions for + @code{O_j}. If the iterated dominance frontier for @code{O_j} + is not pruned, we may end up inserting PHI nodes in blocks that + have one or more edges with no incoming definition for + @code{O_j}. This would lead to uninitialized warnings for + @code{O_j}'s symbol@. + +@item @code{TODO_update_ssa_no_phi}. Update the SSA form without + inserting any new PHI nodes at all. This is used by passes that + have either inserted all the PHI nodes themselves or passes that + need only to patch use-def and def-def chains for virtuals + (e.g., DCE)@. + + +@item @code{TODO_update_ssa_full_phi}. Insert PHI nodes everywhere + they are needed. No pruning of the IDF is done. This is used + by passes that need the PHI nodes for @code{O_j} even if it + means that some arguments will come from the default definition + of @code{O_j}'s symbol (e.g., @code{pass_linear_transform})@. + + WARNING: If you need to use this flag, chances are that your + pass may be doing something wrong. Inserting PHI nodes for an + old name where not all edges carry a new replacement may lead to + silent codegen errors or spurious uninitialized warnings@. + +@item @code{TODO_update_ssa_only_virtuals}. Passes that update the + SSA form on their own may want to delegate the updating of + virtual names to the generic updater. Since FUD chains are + easier to maintain, this simplifies the work they need to do. + NOTE: If this flag is used, any OLD->NEW mappings for real names + are explicitly destroyed and only the symbols marked for + renaming are processed@. +@end itemize + +@subsection Preserving the virtual SSA form +@cindex preserving virtual SSA form + +The virtual SSA form is harder to preserve than the non-virtual SSA form +mainly because the set of virtual operands for a statement may change at +what some would consider unexpected times. In general, any time you +have modified a statement that has virtual operands, you should verify +whether the list of virtual operands has changed, and if so, mark the +newly exposed symbols by calling @code{mark_new_vars_to_rename}. + +There is one additional caveat to preserving virtual SSA form. When the +entire set of virtual operands may be eliminated due to better +disambiguation, a bare SMT will be added to the list of virtual +operands, to signify the non-visible aliases that the are still being +referenced. If the set of bare SMT's may change, +@code{TODO_update_smt_usage} should be added to the todo flags. + +With the current pruning code, this can only occur when constants are +propagated into array references that were previously non-constant, or +address expressions are propagated into their uses. + +@subsection Examining @code{SSA_NAME} nodes +@cindex examining SSA_NAMEs + +The following macros can be used to examine @code{SSA_NAME} nodes + +@defmac SSA_NAME_DEF_STMT (@var{var}) +Returns the statement @var{s} that creates the @code{SSA_NAME} +@var{var}. If @var{s} is an empty statement (i.e., @code{IS_EMPTY_STMT +(@var{s})} returns @code{true}), it means that the first reference to +this variable is a USE or a VUSE@. +@end defmac + +@defmac SSA_NAME_VERSION (@var{var}) +Returns the version number of the @code{SSA_NAME} object @var{var}. +@end defmac + + +@subsection Walking use-def chains + +@deftypefn {Tree SSA function} void walk_use_def_chains (@var{var}, @var{fn}, @var{data}) + +Walks use-def chains starting at the @code{SSA_NAME} node @var{var}. +Calls function @var{fn} at each reaching definition found. Function +@var{FN} takes three arguments: @var{var}, its defining statement +(@var{def_stmt}) and a generic pointer to whatever state information +that @var{fn} may want to maintain (@var{data}). Function @var{fn} is +able to stop the walk by returning @code{true}, otherwise in order to +continue the walk, @var{fn} should return @code{false}. + +Note, that if @var{def_stmt} is a @code{PHI} node, the semantics are +slightly different. For each argument @var{arg} of the PHI node, this +function will: + +@enumerate +@item Walk the use-def chains for @var{arg}. +@item Call @code{FN (@var{arg}, @var{phi}, @var{data})}. +@end enumerate + +Note how the first argument to @var{fn} is no longer the original +variable @var{var}, but the PHI argument currently being examined. +If @var{fn} wants to get at @var{var}, it should call +@code{PHI_RESULT} (@var{phi}). +@end deftypefn + +@subsection Walking the dominator tree + +@deftypefn {Tree SSA function} void walk_dominator_tree (@var{walk_data}, @var{bb}) + +This function walks the dominator tree for the current CFG calling a +set of callback functions defined in @var{struct dom_walk_data} in +@file{domwalk.h}. The call back functions you need to define give you +hooks to execute custom code at various points during traversal: + +@enumerate +@item Once to initialize any local data needed while processing + @var{bb} and its children. This local data is pushed into an + internal stack which is automatically pushed and popped as the + walker traverses the dominator tree. + +@item Once before traversing all the statements in the @var{bb}. + +@item Once for every statement inside @var{bb}. + +@item Once after traversing all the statements and before recursing + into @var{bb}'s dominator children. + +@item It then recurses into all the dominator children of @var{bb}. + +@item After recursing into all the dominator children of @var{bb} it + can, optionally, traverse every statement in @var{bb} again + (i.e., repeating steps 2 and 3). + +@item Once after walking the statements in @var{bb} and @var{bb}'s + dominator children. At this stage, the block local data stack + is popped. +@end enumerate +@end deftypefn + +@node Alias analysis +@section Alias analysis +@cindex alias +@cindex flow-sensitive alias analysis +@cindex flow-insensitive alias analysis + +Alias analysis proceeds in 4 main phases: + +@enumerate +@item Structural alias analysis. + +This phase walks the types for structure variables, and determines which +of the fields can overlap using offset and size of each field. For each +field, a ``subvariable'' called a ``Structure field tag'' (SFT)@ is +created, which represents that field as a separate variable. All +accesses that could possibly overlap with a given field will have +virtual operands for the SFT of that field. + +@smallexample +struct foo +@{ + int a; + int b; +@} +struct foo temp; +int bar (void) +@{ + int tmp1, tmp2, tmp3; + SFT.0_2 = V_MUST_DEF <SFT.0_1> + temp.a = 5; + SFT.1_4 = V_MUST_DEF <SFT.1_3> + temp.b = 6; + + VUSE <SFT.1_4> + tmp1_5 = temp.b; + VUSE <SFT.0_2> + tmp2_6 = temp.a; + + tmp3_7 = tmp1_5 + tmp2_6; + return tmp3_7; +@} +@end smallexample + +If you copy the symbol tag for a variable for some reason, you probably +also want to copy the subvariables for that variable. + +@item Points-to and escape analysis. + +This phase walks the use-def chains in the SSA web looking for +three things: + + @itemize @bullet + @item Assignments of the form @code{P_i = &VAR} + @item Assignments of the form P_i = malloc() + @item Pointers and ADDR_EXPR that escape the current function. + @end itemize + +The concept of `escaping' is the same one used in the Java world. +When a pointer or an ADDR_EXPR escapes, it means that it has been +exposed outside of the current function. So, assignment to +global variables, function arguments and returning a pointer are +all escape sites. + +This is where we are currently limited. Since not everything is +renamed into SSA, we lose track of escape properties when a +pointer is stashed inside a field in a structure, for instance. +In those cases, we are assuming that the pointer does escape. + +We use escape analysis to determine whether a variable is +call-clobbered. Simply put, if an ADDR_EXPR escapes, then the +variable is call-clobbered. If a pointer P_i escapes, then all +the variables pointed-to by P_i (and its memory tag) also escape. + +@item Compute flow-sensitive aliases + +We have two classes of memory tags. Memory tags associated with +the pointed-to data type of the pointers in the program. These +tags are called ``symbol memory tag'' (SMT)@. The other class are +those associated with SSA_NAMEs, called ``name memory tag'' (NMT)@. +The basic idea is that when adding operands for an INDIRECT_REF +*P_i, we will first check whether P_i has a name tag, if it does +we use it, because that will have more precise aliasing +information. Otherwise, we use the standard symbol tag. + +In this phase, we go through all the pointers we found in +points-to analysis and create alias sets for the name memory tags +associated with each pointer P_i. If P_i escapes, we mark +call-clobbered the variables it points to and its tag. + + +@item Compute flow-insensitive aliases + +This pass will compare the alias set of every symbol memory tag and +every addressable variable found in the program. Given a symbol +memory tag SMT and an addressable variable V@. If the alias sets +of SMT and V conflict (as computed by may_alias_p), then V is +marked as an alias tag and added to the alias set of SMT@. +@end enumerate + +For instance, consider the following function: + +@smallexample +foo (int i) +@{ + int *p, *q, a, b; + + if (i > 10) + p = &a; + else + q = &b; + + *p = 3; + *q = 5; + a = b + 2; + return *p; +@} +@end smallexample + +After aliasing analysis has finished, the symbol memory tag for +pointer @code{p} will have two aliases, namely variables @code{a} and +@code{b}. +Every time pointer @code{p} is dereferenced, we want to mark the +operation as a potential reference to @code{a} and @code{b}. + +@smallexample +foo (int i) +@{ + int *p, a, b; + + if (i_2 > 10) + p_4 = &a; + else + p_6 = &b; + # p_1 = PHI <p_4(1), p_6(2)>; + + # a_7 = V_MAY_DEF <a_3>; + # b_8 = V_MAY_DEF <b_5>; + *p_1 = 3; + + # a_9 = V_MAY_DEF <a_7> + # VUSE <b_8> + a_9 = b_8 + 2; + + # VUSE <a_9>; + # VUSE <b_8>; + return *p_1; +@} +@end smallexample + +In certain cases, the list of may aliases for a pointer may grow +too large. This may cause an explosion in the number of virtual +operands inserted in the code. Resulting in increased memory +consumption and compilation time. + +When the number of virtual operands needed to represent aliased +loads and stores grows too large (configurable with @option{--param +max-aliased-vops}), alias sets are grouped to avoid severe +compile-time slow downs and memory consumption. The alias +grouping heuristic proceeds as follows: + +@enumerate +@item Sort the list of pointers in decreasing number of contributed +virtual operands. + +@item Take the first pointer from the list and reverse the role +of the memory tag and its aliases. Usually, whenever an +aliased variable Vi is found to alias with a memory tag +T, we add Vi to the may-aliases set for T@. Meaning that +after alias analysis, we will have: + +@smallexample +may-aliases(T) = @{ V1, V2, V3, ..., Vn @} +@end smallexample + +This means that every statement that references T, will get +@code{n} virtual operands for each of the Vi tags. But, when +alias grouping is enabled, we make T an alias tag and add it +to the alias set of all the Vi variables: + +@smallexample +may-aliases(V1) = @{ T @} +may-aliases(V2) = @{ T @} +... +may-aliases(Vn) = @{ T @} +@end smallexample + +This has two effects: (a) statements referencing T will only get +a single virtual operand, and, (b) all the variables Vi will now +appear to alias each other. So, we lose alias precision to +improve compile time. But, in theory, a program with such a high +level of aliasing should not be very optimizable in the first +place. + +@item Since variables may be in the alias set of more than one +memory tag, the grouping done in step (2) needs to be extended +to all the memory tags that have a non-empty intersection with +the may-aliases set of tag T@. For instance, if we originally +had these may-aliases sets: + +@smallexample +may-aliases(T) = @{ V1, V2, V3 @} +may-aliases(R) = @{ V2, V4 @} +@end smallexample + +In step (2) we would have reverted the aliases for T as: + +@smallexample +may-aliases(V1) = @{ T @} +may-aliases(V2) = @{ T @} +may-aliases(V3) = @{ T @} +@end smallexample + +But note that now V2 is no longer aliased with R@. We could +add R to may-aliases(V2), but we are in the process of +grouping aliases to reduce virtual operands so what we do is +add V4 to the grouping to obtain: + +@smallexample +may-aliases(V1) = @{ T @} +may-aliases(V2) = @{ T @} +may-aliases(V3) = @{ T @} +may-aliases(V4) = @{ T @} +@end smallexample + +@item If the total number of virtual operands due to aliasing is +still above the threshold set by max-alias-vops, go back to (2). +@end enumerate diff --git a/gcc-4.2.1-5666.3/gcc/doc/trouble.texi b/gcc-4.2.1-5666.3/gcc/doc/trouble.texi new file mode 100644 index 000000000..ade026d51 --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/doc/trouble.texi @@ -0,0 +1,1329 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Trouble +@chapter Known Causes of Trouble with GCC +@cindex bugs, known +@cindex installation trouble +@cindex known causes of trouble + +This section describes known problems that affect users of GCC@. Most +of these are not GCC bugs per se---if they were, we would fix them. +But the result for a user may be like the result of a bug. + +Some of these problems are due to bugs in other software, some are +missing features that are too much work to add, and some are places +where people's opinions differ as to what is best. + +@menu +* Actual Bugs:: Bugs we will fix later. +* Cross-Compiler Problems:: Common problems of cross compiling with GCC. +* Interoperation:: Problems using GCC with other compilers, + and with certain linkers, assemblers and debuggers. +* Incompatibilities:: GCC is incompatible with traditional C. +* Fixed Headers:: GCC uses corrected versions of system header files. + This is necessary, but doesn't always work smoothly. +* Standard Libraries:: GCC uses the system C library, which might not be + compliant with the ISO C standard. +* Disappointments:: Regrettable things we can't change, but not quite bugs. +* C++ Misunderstandings:: Common misunderstandings with GNU C++. +* Protoize Caveats:: Things to watch out for when using @code{protoize}. +* Non-bugs:: Things we think are right, but some others disagree. +* Warnings and Errors:: Which problems in your code get warnings, + and which get errors. +@end menu + +@node Actual Bugs +@section Actual Bugs We Haven't Fixed Yet + +@itemize @bullet +@item +The @code{fixincludes} script interacts badly with automounters; if the +directory of system header files is automounted, it tends to be +unmounted while @code{fixincludes} is running. This would seem to be a +bug in the automounter. We don't know any good way to work around it. + +@item +The @code{fixproto} script will sometimes add prototypes for the +@code{sigsetjmp} and @code{siglongjmp} functions that reference the +@code{jmp_buf} type before that type is defined. To work around this, +edit the offending file and place the typedef in front of the +prototypes. +@end itemize + +@node Cross-Compiler Problems +@section Cross-Compiler Problems + +You may run into problems with cross compilation on certain machines, +for several reasons. + +@itemize @bullet +@item +At present, the program @file{mips-tfile} which adds debug +support to object files on MIPS systems does not work in a cross +compile environment. +@end itemize + +@node Interoperation +@section Interoperation + +This section lists various difficulties encountered in using GCC +together with other compilers or with the assemblers, linkers, +libraries and debuggers on certain systems. + +@itemize @bullet +@item +On many platforms, GCC supports a different ABI for C++ than do other +compilers, so the object files compiled by GCC cannot be used with object +files generated by another C++ compiler. + +An area where the difference is most apparent is name mangling. The use +of different name mangling is intentional, to protect you from more subtle +problems. +Compilers differ as to many internal details of C++ implementation, +including: how class instances are laid out, how multiple inheritance is +implemented, and how virtual function calls are handled. If the name +encoding were made the same, your programs would link against libraries +provided from other compilers---but the programs would then crash when +run. Incompatible libraries are then detected at link time, rather than +at run time. + +@item +On some BSD systems, including some versions of Ultrix, use of profiling +causes static variable destructors (currently used only in C++) not to +be run. + +@item +On some SGI systems, when you use @option{-lgl_s} as an option, +it gets translated magically to @samp{-lgl_s -lX11_s -lc_s}. +Naturally, this does not happen when you use GCC@. +You must specify all three options explicitly. + +@item +On a SPARC, GCC aligns all values of type @code{double} on an 8-byte +boundary, and it expects every @code{double} to be so aligned. The Sun +compiler usually gives @code{double} values 8-byte alignment, with one +exception: function arguments of type @code{double} may not be aligned. + +As a result, if a function compiled with Sun CC takes the address of an +argument of type @code{double} and passes this pointer of type +@code{double *} to a function compiled with GCC, dereferencing the +pointer may cause a fatal signal. + +One way to solve this problem is to compile your entire program with GCC@. +Another solution is to modify the function that is compiled with +Sun CC to copy the argument into a local variable; local variables +are always properly aligned. A third solution is to modify the function +that uses the pointer to dereference it via the following function +@code{access_double} instead of directly with @samp{*}: + +@smallexample +inline double +access_double (double *unaligned_ptr) +@{ + union d2i @{ double d; int i[2]; @}; + + union d2i *p = (union d2i *) unaligned_ptr; + union d2i u; + + u.i[0] = p->i[0]; + u.i[1] = p->i[1]; + + return u.d; +@} +@end smallexample + +@noindent +Storing into the pointer can be done likewise with the same union. + +@item +On Solaris, the @code{malloc} function in the @file{libmalloc.a} library +may allocate memory that is only 4 byte aligned. Since GCC on the +SPARC assumes that doubles are 8 byte aligned, this may result in a +fatal signal if doubles are stored in memory allocated by the +@file{libmalloc.a} library. + +The solution is to not use the @file{libmalloc.a} library. Use instead +@code{malloc} and related functions from @file{libc.a}; they do not have +this problem. + +@item +On the HP PA machine, ADB sometimes fails to work on functions compiled +with GCC@. Specifically, it fails to work on functions that use +@code{alloca} or variable-size arrays. This is because GCC doesn't +generate HP-UX unwind descriptors for such functions. It may even be +impossible to generate them. + +@item +Debugging (@option{-g}) is not supported on the HP PA machine, unless you use +the preliminary GNU tools. + +@item +Taking the address of a label may generate errors from the HP-UX +PA assembler. GAS for the PA does not have this problem. + +@item +Using floating point parameters for indirect calls to static functions +will not work when using the HP assembler. There simply is no way for GCC +to specify what registers hold arguments for static functions when using +the HP assembler. GAS for the PA does not have this problem. + +@item +In extremely rare cases involving some very large functions you may +receive errors from the HP linker complaining about an out of bounds +unconditional branch offset. This used to occur more often in previous +versions of GCC, but is now exceptionally rare. If you should run +into it, you can work around by making your function smaller. + +@item +GCC compiled code sometimes emits warnings from the HP-UX assembler of +the form: + +@smallexample +(warning) Use of GR3 when + frame >= 8192 may cause conflict. +@end smallexample + +These warnings are harmless and can be safely ignored. + +@item +In extremely rare cases involving some very large functions you may +receive errors from the AIX Assembler complaining about a displacement +that is too large. If you should run into it, you can work around by +making your function smaller. + +@item +The @file{libstdc++.a} library in GCC relies on the SVR4 dynamic +linker semantics which merges global symbols between libraries and +applications, especially necessary for C++ streams functionality. +This is not the default behavior of AIX shared libraries and dynamic +linking. @file{libstdc++.a} is built on AIX with ``runtime-linking'' +enabled so that symbol merging can occur. To utilize this feature, +the application linked with @file{libstdc++.a} must include the +@option{-Wl,-brtl} flag on the link line. G++ cannot impose this +because this option may interfere with the semantics of the user +program and users may not always use @samp{g++} to link his or her +application. Applications are not required to use the +@option{-Wl,-brtl} flag on the link line---the rest of the +@file{libstdc++.a} library which is not dependent on the symbol +merging semantics will continue to function correctly. + +@item +An application can interpose its own definition of functions for +functions invoked by @file{libstdc++.a} with ``runtime-linking'' +enabled on AIX@. To accomplish this the application must be linked +with ``runtime-linking'' option and the functions explicitly must be +exported by the application (@option{-Wl,-brtl,-bE:exportfile}). + +@item +AIX on the RS/6000 provides support (NLS) for environments outside of +the United States. Compilers and assemblers use NLS to support +locale-specific representations of various objects including +floating-point numbers (@samp{.} vs @samp{,} for separating decimal +fractions). There have been problems reported where the library linked +with GCC does not produce the same floating-point formats that the +assembler accepts. If you have this problem, set the @env{LANG} +environment variable to @samp{C} or @samp{En_US}. + +@item +@opindex fdollars-in-identifiers +Even if you specify @option{-fdollars-in-identifiers}, +you cannot successfully use @samp{$} in identifiers on the RS/6000 due +to a restriction in the IBM assembler. GAS supports these +identifiers. + +@cindex VAX calling convention +@cindex Ultrix calling convention +@item +@opindex fcall-saved +On Ultrix, the Fortran compiler expects registers 2 through 5 to be saved +by function calls. However, the C compiler uses conventions compatible +with BSD Unix: registers 2 through 5 may be clobbered by function calls. + +GCC uses the same convention as the Ultrix C compiler. You can use +these options to produce code compatible with the Fortran compiler: + +@smallexample +-fcall-saved-r2 -fcall-saved-r3 -fcall-saved-r4 -fcall-saved-r5 +@end smallexample +@end itemize + +@node Incompatibilities +@section Incompatibilities of GCC +@cindex incompatibilities of GCC +@opindex traditional + +There are several noteworthy incompatibilities between GNU C and K&R +(non-ISO) versions of C@. + +@itemize @bullet +@cindex string constants +@cindex read-only strings +@cindex shared strings +@item +GCC normally makes string constants read-only. If several +identical-looking string constants are used, GCC stores only one +copy of the string. + +@cindex @code{mktemp}, and constant strings +One consequence is that you cannot call @code{mktemp} with a string +constant argument. The function @code{mktemp} always alters the +string its argument points to. + +@cindex @code{sscanf}, and constant strings +@cindex @code{fscanf}, and constant strings +@cindex @code{scanf}, and constant strings +@c APPLE LOCAL begin fwritable strings. +Another consequence is that @code{sscanf} does not work on some systems +when passed a string constant as its format control string or input. +This is because @code{sscanf} incorrectly tries to write into the string +constant. Likewise @code{fscanf} and @code{scanf}. + +@opindex fwritable-strings +The best solution to these problems is to change the program to use +@code{char}-array variables with initialization strings for these +purposes instead of string constants. But if this is not possible, +you can use the @option{-fwritable-strings} flag, which directs GCC +to handle string constants the same way most C compilers do. +@c APPLE LOCAL end fwritable strings. +@item +@code{-2147483648} is positive. + +This is because 2147483648 cannot fit in the type @code{int}, so +(following the ISO C rules) its data type is @code{unsigned long int}. +Negating this value yields 2147483648 again. + +@item +GCC does not substitute macro arguments when they appear inside of +string constants. For example, the following macro in GCC + +@smallexample +#define foo(a) "a" +@end smallexample + +@noindent +will produce output @code{"a"} regardless of what the argument @var{a} is. + +@cindex @code{setjmp} incompatibilities +@cindex @code{longjmp} incompatibilities +@item +When you use @code{setjmp} and @code{longjmp}, the only automatic +variables guaranteed to remain valid are those declared +@code{volatile}. This is a consequence of automatic register +allocation. Consider this function: + +@smallexample +jmp_buf j; + +foo () +@{ + int a, b; + + a = fun1 (); + if (setjmp (j)) + return a; + + a = fun2 (); + /* @r{@code{longjmp (j)} may occur in @code{fun3}.} */ + return a + fun3 (); +@} +@end smallexample + +Here @code{a} may or may not be restored to its first value when the +@code{longjmp} occurs. If @code{a} is allocated in a register, then +its first value is restored; otherwise, it keeps the last value stored +in it. + +@opindex W +If you use the @option{-W} option with the @option{-O} option, you will +get a warning when GCC thinks such a problem might be possible. + +@item +Programs that use preprocessing directives in the middle of macro +arguments do not work with GCC@. For example, a program like this +will not work: + +@smallexample +@group +foobar ( +#define luser + hack) +@end group +@end smallexample + +ISO C does not permit such a construct. + +@item +K&R compilers allow comments to cross over an inclusion boundary +(i.e.@: started in an include file and ended in the including file). + +@cindex external declaration scope +@cindex scope of external declarations +@cindex declaration scope +@item +Declarations of external variables and functions within a block apply +only to the block containing the declaration. In other words, they +have the same scope as any other declaration in the same place. + +In some other C compilers, a @code{extern} declaration affects all the +rest of the file even if it happens within a block. + +@item +In traditional C, you can combine @code{long}, etc., with a typedef name, +as shown here: + +@smallexample +typedef int foo; +typedef long foo bar; +@end smallexample + +In ISO C, this is not allowed: @code{long} and other type modifiers +require an explicit @code{int}. + +@cindex typedef names as function parameters +@item +PCC allows typedef names to be used as function parameters. + +@item +Traditional C allows the following erroneous pair of declarations to +appear together in a given scope: + +@smallexample +typedef int foo; +typedef foo foo; +@end smallexample + +@item +GCC treats all characters of identifiers as significant. According to +K&R-1 (2.2), ``No more than the first eight characters are significant, +although more may be used.''. Also according to K&R-1 (2.2), ``An +identifier is a sequence of letters and digits; the first character must +be a letter. The underscore _ counts as a letter.'', but GCC also +allows dollar signs in identifiers. + +@cindex whitespace +@item +PCC allows whitespace in the middle of compound assignment operators +such as @samp{+=}. GCC, following the ISO standard, does not +allow this. + +@cindex apostrophes +@cindex ' +@item +GCC complains about unterminated character constants inside of +preprocessing conditionals that fail. Some programs have English +comments enclosed in conditionals that are guaranteed to fail; if these +comments contain apostrophes, GCC will probably report an error. For +example, this code would produce an error: + +@smallexample +#if 0 +You can't expect this to work. +#endif +@end smallexample + +The best solution to such a problem is to put the text into an actual +C comment delimited by @samp{/*@dots{}*/}. + +@item +Many user programs contain the declaration @samp{long time ();}. In the +past, the system header files on many systems did not actually declare +@code{time}, so it did not matter what type your program declared it to +return. But in systems with ISO C headers, @code{time} is declared to +return @code{time_t}, and if that is not the same as @code{long}, then +@samp{long time ();} is erroneous. + +The solution is to change your program to use appropriate system headers +(@code{<time.h>} on systems with ISO C headers) and not to declare +@code{time} if the system header files declare it, or failing that to +use @code{time_t} as the return type of @code{time}. + +@cindex @code{float} as function value type +@item +When compiling functions that return @code{float}, PCC converts it to +a double. GCC actually returns a @code{float}. If you are concerned +with PCC compatibility, you should declare your functions to return +@code{double}; you might as well say what you mean. + +@cindex structures +@cindex unions +@item +When compiling functions that return structures or unions, GCC +output code normally uses a method different from that used on most +versions of Unix. As a result, code compiled with GCC cannot call +a structure-returning function compiled with PCC, and vice versa. + +The method used by GCC is as follows: a structure or union which is +1, 2, 4 or 8 bytes long is returned like a scalar. A structure or union +with any other size is stored into an address supplied by the caller +(usually in a special, fixed register, but on some machines it is passed +on the stack). The target hook @code{TARGET_STRUCT_VALUE_RTX} +tells GCC where to pass this address. + +By contrast, PCC on most target machines returns structures and unions +of any size by copying the data into an area of static storage, and then +returning the address of that storage as if it were a pointer value. +The caller must copy the data from that memory area to the place where +the value is wanted. GCC does not use this method because it is +slower and nonreentrant. + +On some newer machines, PCC uses a reentrant convention for all +structure and union returning. GCC on most of these machines uses a +compatible convention when returning structures and unions in memory, +but still returns small structures and unions in registers. + +@opindex fpcc-struct-return +You can tell GCC to use a compatible convention for all structure and +union returning with the option @option{-fpcc-struct-return}. + +@cindex preprocessing tokens +@cindex preprocessing numbers +@item +GCC complains about program fragments such as @samp{0x74ae-0x4000} +which appear to be two hexadecimal constants separated by the minus +operator. Actually, this string is a single @dfn{preprocessing token}. +Each such token must correspond to one token in C@. Since this does not, +GCC prints an error message. Although it may appear obvious that what +is meant is an operator and two values, the ISO C standard specifically +requires that this be treated as erroneous. + +A @dfn{preprocessing token} is a @dfn{preprocessing number} if it +begins with a digit and is followed by letters, underscores, digits, +periods and @samp{e+}, @samp{e-}, @samp{E+}, @samp{E-}, @samp{p+}, +@samp{p-}, @samp{P+}, or @samp{P-} character sequences. (In strict C89 +mode, the sequences @samp{p+}, @samp{p-}, @samp{P+} and @samp{P-} cannot +appear in preprocessing numbers.) + +To make the above program fragment valid, place whitespace in front of +the minus sign. This whitespace will end the preprocessing number. +@end itemize + +@node Fixed Headers +@section Fixed Header Files + +GCC needs to install corrected versions of some system header files. +This is because most target systems have some header files that won't +work with GCC unless they are changed. Some have bugs, some are +incompatible with ISO C, and some depend on special features of other +compilers. + +Installing GCC automatically creates and installs the fixed header +files, by running a program called @code{fixincludes}. Normally, you +don't need to pay attention to this. But there are cases where it +doesn't do the right thing automatically. + +@itemize @bullet +@item +If you update the system's header files, such as by installing a new +system version, the fixed header files of GCC are not automatically +updated. They can be updated using the @command{mkheaders} script +installed in +@file{@var{libexecdir}/gcc/@var{target}/@var{version}/install-tools/}. + +@item +On some systems, header file directories contain +machine-specific symbolic links in certain places. This makes it +possible to share most of the header files among hosts running the +same version of the system on different machine models. + +The programs that fix the header files do not understand this special +way of using symbolic links; therefore, the directory of fixed header +files is good only for the machine model used to build it. + +It is possible to make separate sets of fixed header files for the +different machine models, and arrange a structure of symbolic links so +as to use the proper set, but you'll have to do this by hand. +@end itemize + +@node Standard Libraries +@section Standard Libraries + +@opindex Wall +GCC by itself attempts to be a conforming freestanding implementation. +@xref{Standards,,Language Standards Supported by GCC}, for details of +what this means. Beyond the library facilities required of such an +implementation, the rest of the C library is supplied by the vendor of +the operating system. If that C library doesn't conform to the C +standards, then your programs might get warnings (especially when using +@option{-Wall}) that you don't expect. + +For example, the @code{sprintf} function on SunOS 4.1.3 returns +@code{char *} while the C standard says that @code{sprintf} returns an +@code{int}. The @code{fixincludes} program could make the prototype for +this function match the Standard, but that would be wrong, since the +function will still return @code{char *}. + +If you need a Standard compliant library, then you need to find one, as +GCC does not provide one. The GNU C library (called @code{glibc}) +provides ISO C, POSIX, BSD, SystemV and X/Open compatibility for +GNU/Linux and HURD-based GNU systems; no recent version of it supports +other systems, though some very old versions did. Version 2.2 of the +GNU C library includes nearly complete C99 support. You could also ask +your operating system vendor if newer libraries are available. + +@node Disappointments +@section Disappointments and Misunderstandings + +These problems are perhaps regrettable, but we don't know any practical +way around them. + +@itemize @bullet +@item +Certain local variables aren't recognized by debuggers when you compile +with optimization. + +This occurs because sometimes GCC optimizes the variable out of +existence. There is no way to tell the debugger how to compute the +value such a variable ``would have had'', and it is not clear that would +be desirable anyway. So GCC simply does not mention the eliminated +variable when it writes debugging information. + +You have to expect a certain amount of disagreement between the +executable and your source code, when you use optimization. + +@cindex conflicting types +@cindex scope of declaration +@item +Users often think it is a bug when GCC reports an error for code +like this: + +@smallexample +int foo (struct mumble *); + +struct mumble @{ @dots{} @}; + +int foo (struct mumble *x) +@{ @dots{} @} +@end smallexample + +This code really is erroneous, because the scope of @code{struct +mumble} in the prototype is limited to the argument list containing it. +It does not refer to the @code{struct mumble} defined with file scope +immediately below---they are two unrelated types with similar names in +different scopes. + +But in the definition of @code{foo}, the file-scope type is used +because that is available to be inherited. Thus, the definition and +the prototype do not match, and you get an error. + +This behavior may seem silly, but it's what the ISO standard specifies. +It is easy enough for you to make your code work by moving the +definition of @code{struct mumble} above the prototype. It's not worth +being incompatible with ISO C just to avoid an error for the example +shown above. + +@item +Accesses to bit-fields even in volatile objects works by accessing larger +objects, such as a byte or a word. You cannot rely on what size of +object is accessed in order to read or write the bit-field; it may even +vary for a given bit-field according to the precise usage. + +If you care about controlling the amount of memory that is accessed, use +volatile but do not use bit-fields. + +@item +GCC comes with shell scripts to fix certain known problems in system +header files. They install corrected copies of various header files in +a special directory where only GCC will normally look for them. The +scripts adapt to various systems by searching all the system header +files for the problem cases that we know about. + +If new system header files are installed, nothing automatically arranges +to update the corrected header files. They can be updated using the +@command{mkheaders} script installed in +@file{@var{libexecdir}/gcc/@var{target}/@var{version}/install-tools/}. + +@item +@cindex floating point precision +On 68000 and x86 systems, for instance, you can get paradoxical results +if you test the precise values of floating point numbers. For example, +you can find that a floating point value which is not a NaN is not equal +to itself. This results from the fact that the floating point registers +hold a few more bits of precision than fit in a @code{double} in memory. +Compiled code moves values between memory and floating point registers +at its convenience, and moving them into memory truncates them. + +@opindex ffloat-store +You can partially avoid this problem by using the @option{-ffloat-store} +option (@pxref{Optimize Options}). + +@item +On AIX and other platforms without weak symbol support, templates +need to be instantiated explicitly and symbols for static members +of templates will not be generated. + +@item +On AIX, GCC scans object files and library archives for static +constructors and destructors when linking an application before the +linker prunes unreferenced symbols. This is necessary to prevent the +AIX linker from mistakenly assuming that static constructor or +destructor are unused and removing them before the scanning can occur. +All static constructors and destructors found will be referenced even +though the modules in which they occur may not be used by the program. +This may lead to both increased executable size and unexpected symbol +references. +@end itemize + +@node C++ Misunderstandings +@section Common Misunderstandings with GNU C++ + +@cindex misunderstandings in C++ +@cindex surprises in C++ +@cindex C++ misunderstandings +C++ is a complex language and an evolving one, and its standard +definition (the ISO C++ standard) was only recently completed. As a +result, your C++ compiler may occasionally surprise you, even when its +behavior is correct. This section discusses some areas that frequently +give rise to questions of this sort. + +@menu +* Static Definitions:: Static member declarations are not definitions +* Name lookup:: Name lookup, templates, and accessing members of base classes +* Temporaries:: Temporaries may vanish before you expect +* Copy Assignment:: Copy Assignment operators copy virtual bases twice +@end menu + +@node Static Definitions +@subsection Declare @emph{and} Define Static Members + +@cindex C++ static data, declaring and defining +@cindex static data in C++, declaring and defining +@cindex declaring static data in C++ +@cindex defining static data in C++ +When a class has static data members, it is not enough to @emph{declare} +the static member; you must also @emph{define} it. For example: + +@smallexample +class Foo +@{ + @dots{} + void method(); + static int bar; +@}; +@end smallexample + +This declaration only establishes that the class @code{Foo} has an +@code{int} named @code{Foo::bar}, and a member function named +@code{Foo::method}. But you still need to define @emph{both} +@code{method} and @code{bar} elsewhere. According to the ISO +standard, you must supply an initializer in one (and only one) source +file, such as: + +@smallexample +int Foo::bar = 0; +@end smallexample + +Other C++ compilers may not correctly implement the standard behavior. +As a result, when you switch to @command{g++} from one of these compilers, +you may discover that a program that appeared to work correctly in fact +does not conform to the standard: @command{g++} reports as undefined +symbols any static data members that lack definitions. + + +@node Name lookup +@subsection Name lookup, templates, and accessing members of base classes + +@cindex base class members +@cindex two-stage name lookup +@cindex dependent name lookup + +The C++ standard prescribes that all names that are not dependent on +template parameters are bound to their present definitions when parsing +a template function or class.@footnote{The C++ standard just uses the +term ``dependent'' for names that depend on the type or value of +template parameters. This shorter term will also be used in the rest of +this section.} Only names that are dependent are looked up at the point +of instantiation. For example, consider + +@smallexample + void foo(double); + + struct A @{ + template <typename T> + void f () @{ + foo (1); // @r{1} + int i = N; // @r{2} + T t; + t.bar(); // @r{3} + foo (t); // @r{4} + @} + + static const int N; + @}; +@end smallexample + +Here, the names @code{foo} and @code{N} appear in a context that does +not depend on the type of @code{T}. The compiler will thus require that +they are defined in the context of use in the template, not only before +the point of instantiation, and will here use @code{::foo(double)} and +@code{A::N}, respectively. In particular, it will convert the integer +value to a @code{double} when passing it to @code{::foo(double)}. + +Conversely, @code{bar} and the call to @code{foo} in the fourth marked +line are used in contexts that do depend on the type of @code{T}, so +they are only looked up at the point of instantiation, and you can +provide declarations for them after declaring the template, but before +instantiating it. In particular, if you instantiate @code{A::f<int>}, +the last line will call an overloaded @code{::foo(int)} if one was +provided, even if after the declaration of @code{struct A}. + +This distinction between lookup of dependent and non-dependent names is +called two-stage (or dependent) name lookup. G++ implements it +since version 3.4. + +Two-stage name lookup sometimes leads to situations with behavior +different from non-template codes. The most common is probably this: + +@smallexample + template <typename T> struct Base @{ + int i; + @}; + + template <typename T> struct Derived : public Base<T> @{ + int get_i() @{ return i; @} + @}; +@end smallexample + +In @code{get_i()}, @code{i} is not used in a dependent context, so the +compiler will look for a name declared at the enclosing namespace scope +(which is the global scope here). It will not look into the base class, +since that is dependent and you may declare specializations of +@code{Base} even after declaring @code{Derived}, so the compiler can't +really know what @code{i} would refer to. If there is no global +variable @code{i}, then you will get an error message. + +In order to make it clear that you want the member of the base class, +you need to defer lookup until instantiation time, at which the base +class is known. For this, you need to access @code{i} in a dependent +context, by either using @code{this->i} (remember that @code{this} is of +type @code{Derived<T>*}, so is obviously dependent), or using +@code{Base<T>::i}. Alternatively, @code{Base<T>::i} might be brought +into scope by a @code{using}-declaration. + +Another, similar example involves calling member functions of a base +class: + +@smallexample + template <typename T> struct Base @{ + int f(); + @}; + + template <typename T> struct Derived : Base<T> @{ + int g() @{ return f(); @}; + @}; +@end smallexample + +Again, the call to @code{f()} is not dependent on template arguments +(there are no arguments that depend on the type @code{T}, and it is also +not otherwise specified that the call should be in a dependent context). +Thus a global declaration of such a function must be available, since +the one in the base class is not visible until instantiation time. The +compiler will consequently produce the following error message: + +@smallexample + x.cc: In member function `int Derived<T>::g()': + x.cc:6: error: there are no arguments to `f' that depend on a template + parameter, so a declaration of `f' must be available + x.cc:6: error: (if you use `-fpermissive', G++ will accept your code, but + allowing the use of an undeclared name is deprecated) +@end smallexample + +To make the code valid either use @code{this->f()}, or +@code{Base<T>::f()}. Using the @option{-fpermissive} flag will also let +the compiler accept the code, by marking all function calls for which no +declaration is visible at the time of definition of the template for +later lookup at instantiation time, as if it were a dependent call. +We do not recommend using @option{-fpermissive} to work around invalid +code, and it will also only catch cases where functions in base classes +are called, not where variables in base classes are used (as in the +example above). + +Note that some compilers (including G++ versions prior to 3.4) get these +examples wrong and accept above code without an error. Those compilers +do not implement two-stage name lookup correctly. + + +@node Temporaries +@subsection Temporaries May Vanish Before You Expect + +@cindex temporaries, lifetime of +@cindex portions of temporary objects, pointers to +It is dangerous to use pointers or references to @emph{portions} of a +temporary object. The compiler may very well delete the object before +you expect it to, leaving a pointer to garbage. The most common place +where this problem crops up is in classes like string classes, +especially ones that define a conversion function to type @code{char *} +or @code{const char *}---which is one reason why the standard +@code{string} class requires you to call the @code{c_str} member +function. However, any class that returns a pointer to some internal +structure is potentially subject to this problem. + +For example, a program may use a function @code{strfunc} that returns +@code{string} objects, and another function @code{charfunc} that +operates on pointers to @code{char}: + +@smallexample +string strfunc (); +void charfunc (const char *); + +void +f () +@{ + const char *p = strfunc().c_str(); + @dots{} + charfunc (p); + @dots{} + charfunc (p); +@} +@end smallexample + +@noindent +In this situation, it may seem reasonable to save a pointer to the C +string returned by the @code{c_str} member function and use that rather +than call @code{c_str} repeatedly. However, the temporary string +created by the call to @code{strfunc} is destroyed after @code{p} is +initialized, at which point @code{p} is left pointing to freed memory. + +Code like this may run successfully under some other compilers, +particularly obsolete cfront-based compilers that delete temporaries +along with normal local variables. However, the GNU C++ behavior is +standard-conforming, so if your program depends on late destruction of +temporaries it is not portable. + +The safe way to write such code is to give the temporary a name, which +forces it to remain until the end of the scope of the name. For +example: + +@smallexample +const string& tmp = strfunc (); +charfunc (tmp.c_str ()); +@end smallexample + +@node Copy Assignment +@subsection Implicit Copy-Assignment for Virtual Bases + +When a base class is virtual, only one subobject of the base class +belongs to each full object. Also, the constructors and destructors are +invoked only once, and called from the most-derived class. However, such +objects behave unspecified when being assigned. For example: + +@smallexample +struct Base@{ + char *name; + Base(char *n) : name(strdup(n))@{@} + Base& operator= (const Base& other)@{ + free (name); + name = strdup (other.name); + @} +@}; + +struct A:virtual Base@{ + int val; + A():Base("A")@{@} +@}; + +struct B:virtual Base@{ + int bval; + B():Base("B")@{@} +@}; + +struct Derived:public A, public B@{ + Derived():Base("Derived")@{@} +@}; + +void func(Derived &d1, Derived &d2) +@{ + d1 = d2; +@} +@end smallexample + +The C++ standard specifies that @samp{Base::Base} is only called once +when constructing or copy-constructing a Derived object. It is +unspecified whether @samp{Base::operator=} is called more than once when +the implicit copy-assignment for Derived objects is invoked (as it is +inside @samp{func} in the example). + +G++ implements the ``intuitive'' algorithm for copy-assignment: assign all +direct bases, then assign all members. In that algorithm, the virtual +base subobject can be encountered more than once. In the example, copying +proceeds in the following order: @samp{val}, @samp{name} (via +@code{strdup}), @samp{bval}, and @samp{name} again. + +If application code relies on copy-assignment, a user-defined +copy-assignment operator removes any uncertainties. With such an +operator, the application can define whether and how the virtual base +subobject is assigned. + +@node Protoize Caveats +@section Caveats of using @command{protoize} + +The conversion programs @command{protoize} and @command{unprotoize} can +sometimes change a source file in a way that won't work unless you +rearrange it. + +@itemize @bullet +@item +@command{protoize} can insert references to a type name or type tag before +the definition, or in a file where they are not defined. + +If this happens, compiler error messages should show you where the new +references are, so fixing the file by hand is straightforward. + +@item +There are some C constructs which @command{protoize} cannot figure out. +For example, it can't determine argument types for declaring a +pointer-to-function variable; this you must do by hand. @command{protoize} +inserts a comment containing @samp{???} each time it finds such a +variable; so you can find all such variables by searching for this +string. ISO C does not require declaring the argument types of +pointer-to-function types. + +@item +Using @command{unprotoize} can easily introduce bugs. If the program +relied on prototypes to bring about conversion of arguments, these +conversions will not take place in the program without prototypes. +One case in which you can be sure @command{unprotoize} is safe is when +you are removing prototypes that were made with @command{protoize}; if +the program worked before without any prototypes, it will work again +without them. + +@opindex Wconversion +You can find all the places where this problem might occur by compiling +the program with the @option{-Wconversion} option. It prints a warning +whenever an argument is converted. + +@item +Both conversion programs can be confused if there are macro calls in and +around the text to be converted. In other words, the standard syntax +for a declaration or definition must not result from expanding a macro. +This problem is inherent in the design of C and cannot be fixed. If +only a few functions have confusing macro calls, you can easily convert +them manually. + +@item +@command{protoize} cannot get the argument types for a function whose +definition was not actually compiled due to preprocessing conditionals. +When this happens, @command{protoize} changes nothing in regard to such +a function. @command{protoize} tries to detect such instances and warn +about them. + +You can generally work around this problem by using @command{protoize} step +by step, each time specifying a different set of @option{-D} options for +compilation, until all of the functions have been converted. There is +no automatic way to verify that you have got them all, however. + +@item +Confusion may result if there is an occasion to convert a function +declaration or definition in a region of source code where there is more +than one formal parameter list present. Thus, attempts to convert code +containing multiple (conditionally compiled) versions of a single +function header (in the same vicinity) may not produce the desired (or +expected) results. + +If you plan on converting source files which contain such code, it is +recommended that you first make sure that each conditionally compiled +region of source code which contains an alternative function header also +contains at least one additional follower token (past the final right +parenthesis of the function header). This should circumvent the +problem. + +@item +@command{unprotoize} can become confused when trying to convert a function +definition or declaration which contains a declaration for a +pointer-to-function formal argument which has the same name as the +function being defined or declared. We recommend you avoid such choices +of formal parameter names. + +@item +You might also want to correct some of the indentation by hand and break +long lines. (The conversion programs don't write lines longer than +eighty characters in any case.) +@end itemize + +@node Non-bugs +@section Certain Changes We Don't Want to Make + +This section lists changes that people frequently request, but which +we do not make because we think GCC is better without them. + +@itemize @bullet +@item +Checking the number and type of arguments to a function which has an +old-fashioned definition and no prototype. + +Such a feature would work only occasionally---only for calls that appear +in the same file as the called function, following the definition. The +only way to check all calls reliably is to add a prototype for the +function. But adding a prototype eliminates the motivation for this +feature. So the feature is not worthwhile. + +@item +Warning about using an expression whose type is signed as a shift count. + +Shift count operands are probably signed more often than unsigned. +Warning about this would cause far more annoyance than good. + +@item +Warning about assigning a signed value to an unsigned variable. + +Such assignments must be very common; warning about them would cause +more annoyance than good. + +@item +Warning when a non-void function value is ignored. + +C contains many standard functions that return a value that most +programs choose to ignore. One obvious example is @code{printf}. +Warning about this practice only leads the defensive programmer to +clutter programs with dozens of casts to @code{void}. Such casts are +required so frequently that they become visual noise. Writing those +casts becomes so automatic that they no longer convey useful +information about the intentions of the programmer. For functions +where the return value should never be ignored, use the +@code{warn_unused_result} function attribute (@pxref{Function +Attributes}). + +@item +@opindex fshort-enums +Making @option{-fshort-enums} the default. + +This would cause storage layout to be incompatible with most other C +compilers. And it doesn't seem very important, given that you can get +the same result in other ways. The case where it matters most is when +the enumeration-valued object is inside a structure, and in that case +you can specify a field width explicitly. + +@item +Making bit-fields unsigned by default on particular machines where ``the +ABI standard'' says to do so. + +The ISO C standard leaves it up to the implementation whether a bit-field +declared plain @code{int} is signed or not. This in effect creates two +alternative dialects of C@. + +@opindex fsigned-bitfields +@opindex funsigned-bitfields +The GNU C compiler supports both dialects; you can specify the signed +dialect with @option{-fsigned-bitfields} and the unsigned dialect with +@option{-funsigned-bitfields}. However, this leaves open the question of +which dialect to use by default. + +Currently, the preferred dialect makes plain bit-fields signed, because +this is simplest. Since @code{int} is the same as @code{signed int} in +every other context, it is cleanest for them to be the same in bit-fields +as well. + +Some computer manufacturers have published Application Binary Interface +standards which specify that plain bit-fields should be unsigned. It is +a mistake, however, to say anything about this issue in an ABI@. This is +because the handling of plain bit-fields distinguishes two dialects of C@. +Both dialects are meaningful on every type of machine. Whether a +particular object file was compiled using signed bit-fields or unsigned +is of no concern to other object files, even if they access the same +bit-fields in the same data structures. + +A given program is written in one or the other of these two dialects. +The program stands a chance to work on most any machine if it is +compiled with the proper dialect. It is unlikely to work at all if +compiled with the wrong dialect. + +Many users appreciate the GNU C compiler because it provides an +environment that is uniform across machines. These users would be +inconvenienced if the compiler treated plain bit-fields differently on +certain machines. + +Occasionally users write programs intended only for a particular machine +type. On these occasions, the users would benefit if the GNU C compiler +were to support by default the same dialect as the other compilers on +that machine. But such applications are rare. And users writing a +program to run on more than one type of machine cannot possibly benefit +from this kind of compatibility. + +This is why GCC does and will treat plain bit-fields in the same +fashion on all types of machines (by default). + +There are some arguments for making bit-fields unsigned by default on all +machines. If, for example, this becomes a universal de facto standard, +it would make sense for GCC to go along with it. This is something +to be considered in the future. + +(Of course, users strongly concerned about portability should indicate +explicitly in each bit-field whether it is signed or not. In this way, +they write programs which have the same meaning in both C dialects.) + +@item +@opindex ansi +@opindex std +Undefining @code{__STDC__} when @option{-ansi} is not used. + +Currently, GCC defines @code{__STDC__} unconditionally. This provides +good results in practice. + +Programmers normally use conditionals on @code{__STDC__} to ask whether +it is safe to use certain features of ISO C, such as function +prototypes or ISO token concatenation. Since plain @command{gcc} supports +all the features of ISO C, the correct answer to these questions is +``yes''. + +Some users try to use @code{__STDC__} to check for the availability of +certain library facilities. This is actually incorrect usage in an ISO +C program, because the ISO C standard says that a conforming +freestanding implementation should define @code{__STDC__} even though it +does not have the library facilities. @samp{gcc -ansi -pedantic} is a +conforming freestanding implementation, and it is therefore required to +define @code{__STDC__}, even though it does not come with an ISO C +library. + +Sometimes people say that defining @code{__STDC__} in a compiler that +does not completely conform to the ISO C standard somehow violates the +standard. This is illogical. The standard is a standard for compilers +that claim to support ISO C, such as @samp{gcc -ansi}---not for other +compilers such as plain @command{gcc}. Whatever the ISO C standard says +is relevant to the design of plain @command{gcc} without @option{-ansi} only +for pragmatic reasons, not as a requirement. + +GCC normally defines @code{__STDC__} to be 1, and in addition +defines @code{__STRICT_ANSI__} if you specify the @option{-ansi} option, +or a @option{-std} option for strict conformance to some version of ISO C@. +On some hosts, system include files use a different convention, where +@code{__STDC__} is normally 0, but is 1 if the user specifies strict +conformance to the C Standard. GCC follows the host convention when +processing system include files, but when processing user files it follows +the usual GNU C convention. + +@item +Undefining @code{__STDC__} in C++. + +Programs written to compile with C++-to-C translators get the +value of @code{__STDC__} that goes with the C compiler that is +subsequently used. These programs must test @code{__STDC__} +to determine what kind of C preprocessor that compiler uses: +whether they should concatenate tokens in the ISO C fashion +or in the traditional fashion. + +These programs work properly with GNU C++ if @code{__STDC__} is defined. +They would not work otherwise. + +In addition, many header files are written to provide prototypes in ISO +C but not in traditional C@. Many of these header files can work without +change in C++ provided @code{__STDC__} is defined. If @code{__STDC__} +is not defined, they will all fail, and will all need to be changed to +test explicitly for C++ as well. + +@item +Deleting ``empty'' loops. + +Historically, GCC has not deleted ``empty'' loops under the +assumption that the most likely reason you would put one in a program is +to have a delay, so deleting them will not make real programs run any +faster. + +However, the rationale here is that optimization of a nonempty loop +cannot produce an empty one. This held for carefully written C compiled +with less powerful optimizers but is not always the case for carefully +written C++ or with more powerful optimizers. +Thus GCC will remove operations from loops whenever it can determine +those operations are not externally visible (apart from the time taken +to execute them, of course). In case the loop can be proved to be finite, +GCC will also remove the loop itself. + +Be aware of this when performing timing tests, for instance the +following loop can be completely removed, provided +@code{some_expression} can provably not change any global state. + +@smallexample +@{ + int sum = 0; + int ix; + + for (ix = 0; ix != 10000; ix++) + sum += some_expression; +@} +@end smallexample + +Even though @code{sum} is accumulated in the loop, no use is made of +that summation, so the accumulation can be removed. + +@item +Making side effects happen in the same order as in some other compiler. + +@cindex side effects, order of evaluation +@cindex order of evaluation, side effects +It is never safe to depend on the order of evaluation of side effects. +For example, a function call like this may very well behave differently +from one compiler to another: + +@smallexample +void func (int, int); + +int i = 2; +func (i++, i++); +@end smallexample + +There is no guarantee (in either the C or the C++ standard language +definitions) that the increments will be evaluated in any particular +order. Either increment might happen first. @code{func} might get the +arguments @samp{2, 3}, or it might get @samp{3, 2}, or even @samp{2, 2}. + +@item +Making certain warnings into errors by default. + +Some ISO C testsuites report failure when the compiler does not produce +an error message for a certain program. + +@opindex pedantic-errors +ISO C requires a ``diagnostic'' message for certain kinds of invalid +programs, but a warning is defined by GCC to count as a diagnostic. If +GCC produces a warning but not an error, that is correct ISO C support. +If testsuites call this ``failure'', they should be run with the GCC +option @option{-pedantic-errors}, which will turn these warnings into +errors. + +@end itemize + +@node Warnings and Errors +@section Warning Messages and Error Messages + +@cindex error messages +@cindex warnings vs errors +@cindex messages, warning and error +The GNU compiler can produce two kinds of diagnostics: errors and +warnings. Each kind has a different purpose: + +@itemize @w{} +@item +@dfn{Errors} report problems that make it impossible to compile your +program. GCC reports errors with the source file name and line +number where the problem is apparent. + +@item +@dfn{Warnings} report other unusual conditions in your code that +@emph{may} indicate a problem, although compilation can (and does) +proceed. Warning messages also report the source file name and line +number, but include the text @samp{warning:} to distinguish them +from error messages. +@end itemize + +Warnings may indicate danger points where you should check to make sure +that your program really does what you intend; or the use of obsolete +features; or the use of nonstandard features of GNU C or C++. Many +warnings are issued only if you ask for them, with one of the @option{-W} +options (for instance, @option{-Wall} requests a variety of useful +warnings). + +@opindex pedantic +@opindex pedantic-errors +GCC always tries to compile your program if possible; it never +gratuitously rejects a program whose meaning is clear merely because +(for instance) it fails to conform to a standard. In some cases, +however, the C and C++ standards specify that certain extensions are +forbidden, and a diagnostic @emph{must} be issued by a conforming +compiler. The @option{-pedantic} option tells GCC to issue warnings in +such cases; @option{-pedantic-errors} says to make them errors instead. +This does not mean that @emph{all} non-ISO constructs get warnings +or errors. + +@xref{Warning Options,,Options to Request or Suppress Warnings}, for +more detail on these and related command-line options. |