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diff --git a/gcc-4.9/gcc/doc/gccint.info b/gcc-4.9/gcc/doc/gccint.info deleted file mode 100644 index c4b7319c9..000000000 --- a/gcc-4.9/gcc/doc/gccint.info +++ /dev/null @@ -1,50307 +0,0 @@ -This is gccint.info, produced by makeinfo version 5.1 from gccint.texi. - -Copyright (C) 1988-2014 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 1.3 or -any later version published by the Free Software Foundation; with the -Invariant Sections being "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. -INFO-DIR-SECTION Software development -START-INFO-DIR-ENTRY -* gccint: (gccint). Internals of the GNU Compiler Collection. -END-INFO-DIR-ENTRY - - This file documents the internals of the GNU compilers. - - Copyright (C) 1988-2014 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 1.3 or -any later version published by the Free Software Foundation; with the -Invariant Sections being "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. - - -File: gccint.info, Node: Top, Next: Contributing, Up: (DIR) - -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 the compilers (GCC) -version 4.9.0. The use of the GNU compilers is documented in a separate -manual. *Note Introduction: (gcc)Top. - - This manual is mainly a reference manual rather than a tutorial. It -discusses how to contribute to GCC (*note Contributing::), the -characteristics of the machines supported by GCC as hosts and targets -(*note Portability::), how GCC relates to the ABIs on such systems -(*note Interface::), and the characteristics of the languages for which -GCC front ends are written (*note 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 -<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. -* Testsuites:: GCC testsuites. -* Options:: Option specification files. -* Passes:: Order of passes, what they do, and what each file is for. -* GENERIC:: Language-independent representation generated by Front Ends -* GIMPLE:: Tuple representation used by Tree SSA optimizers -* Tree SSA:: Analysis and optimization of GIMPLE -* RTL:: Machine-dependent low-level intermediate representation. -* Control Flow:: Maintaining and manipulating the control flow graph. -* 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 'xm-MACHINE.h' file. -* Fragments:: Writing the 't-TARGET' and 'x-HOST' files. -* Collect2:: How 'collect2' works; how it finds 'ld'. -* Header Dirs:: Understanding the standard header file directories. -* Type Information:: GCC's memory management; generating type information. -* Plugins:: Extending the compiler with plugins. -* LTO:: Using Link-Time Optimization. - -* 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. - - -File: gccint.info, Node: Contributing, Next: Portability, Up: Top - -1 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 -<http://gcc.gnu.org/svn.html>). Source and binary snapshots are also -available for FTP; see <http://gcc.gnu.org/snapshots.html>. - - If you would like to work on improvements to GCC, please read the -advice at these URLs: - - <http://gcc.gnu.org/contribute.html> - <http://gcc.gnu.org/contributewhy.html> - -for information on how to make useful contributions and avoid -duplication of effort. Suggested projects are listed at -<http://gcc.gnu.org/projects/>. - - -File: gccint.info, Node: Portability, Next: Interface, Prev: Contributing, Up: Top - -2 GCC and Portability -********************* - -GCC itself aims to be portable to any machine where '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 'int' type. '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. - - 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 'abort'. Fortunately, the new strategies can be -added in a machine-independent fashion, and will affect only the target -machines that need them. - - -File: gccint.info, Node: Interface, Next: Libgcc, Prev: Portability, Up: Top - -3 Interfacing to GCC Output -*************************** - -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 (*note Target Macros::). - - 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 'int' or '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 '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. - - 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. - - If you use 'longjmp', beware of automatic variables. ISO C says that -automatic variables that are not declared 'volatile' have undefined -values after a '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. - - -File: gccint.info, Node: Libgcc, Next: Languages, Prev: Interface, Up: Top - -4 The GCC low-level runtime library -*********************************** - -GCC provides a low-level runtime library, 'libgcc.a' or '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 'libgcc' handle arithmetic operations that the -target processor cannot perform directly. This includes integer -multiply and divide on some machines, and all floating-point and -fixed-point operations on other machines. '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 'memcpy' -and 'memset', in some cases. The set of routines that GCC may possibly -use is documented in *note (gcc)Other Builtins::. - - These routines take arguments and return values of a specific machine -mode, not a specific C type. *Note Machine Modes::, for an explanation -of this concept. For illustrative purposes, in this chapter the -floating point type 'float' is assumed to correspond to 'SFmode'; -'double' to 'DFmode'; and 'long double' to both 'TFmode' and 'XFmode'. -Similarly, the integer types 'int' and 'unsigned int' correspond to -'SImode'; 'long' and 'unsigned long' to 'DImode'; and 'long long' and -'unsigned long long' to 'TImode'. - -* Menu: - -* Integer library routines:: -* Soft float library routines:: -* Decimal float library routines:: -* Fixed-point fractional library routines:: -* Exception handling routines:: -* Miscellaneous routines:: - - -File: gccint.info, Node: Integer library routines, Next: Soft float library routines, Up: Libgcc - -4.1 Routines for integer arithmetic -=================================== - -The integer arithmetic routines are used on platforms that don't provide -hardware support for arithmetic operations on some modes. - -4.1.1 Arithmetic functions --------------------------- - - -- Runtime Function: int __ashlsi3 (int A, int B) - -- Runtime Function: long __ashldi3 (long A, int B) - -- Runtime Function: long long __ashlti3 (long long A, int B) - These functions return the result of shifting A left by B bits. - - -- Runtime Function: int __ashrsi3 (int A, int B) - -- Runtime Function: long __ashrdi3 (long A, int B) - -- Runtime Function: long long __ashrti3 (long long A, int B) - These functions return the result of arithmetically shifting A - right by B bits. - - -- Runtime Function: int __divsi3 (int A, int B) - -- Runtime Function: long __divdi3 (long A, long B) - -- Runtime Function: long long __divti3 (long long A, long long B) - These functions return the quotient of the signed division of A and - B. - - -- Runtime Function: int __lshrsi3 (int A, int B) - -- Runtime Function: long __lshrdi3 (long A, int B) - -- Runtime Function: long long __lshrti3 (long long A, int B) - These functions return the result of logically shifting A right by - B bits. - - -- Runtime Function: int __modsi3 (int A, int B) - -- Runtime Function: long __moddi3 (long A, long B) - -- Runtime Function: long long __modti3 (long long A, long long B) - These functions return the remainder of the signed division of A - and B. - - -- Runtime Function: int __mulsi3 (int A, int B) - -- Runtime Function: long __muldi3 (long A, long B) - -- Runtime Function: long long __multi3 (long long A, long long B) - These functions return the product of A and B. - - -- Runtime Function: long __negdi2 (long A) - -- Runtime Function: long long __negti2 (long long A) - These functions return the negation of A. - - -- Runtime Function: unsigned int __udivsi3 (unsigned int A, unsigned - int B) - -- Runtime Function: unsigned long __udivdi3 (unsigned long A, unsigned - long B) - -- Runtime Function: unsigned long long __udivti3 (unsigned long long - A, unsigned long long B) - These functions return the quotient of the unsigned division of A - and B. - - -- Runtime Function: unsigned long __udivmoddi4 (unsigned long A, - unsigned long B, unsigned long *C) - -- Runtime Function: unsigned long long __udivmodti4 (unsigned long - long A, unsigned long long B, unsigned long long *C) - These functions calculate both the quotient and remainder of the - unsigned division of A and B. The return value is the quotient, - and the remainder is placed in variable pointed to by C. - - -- Runtime Function: unsigned int __umodsi3 (unsigned int A, unsigned - int B) - -- Runtime Function: unsigned long __umoddi3 (unsigned long A, unsigned - long B) - -- Runtime Function: unsigned long long __umodti3 (unsigned long long - A, unsigned long long B) - These functions return the remainder of the unsigned division of A - and B. - -4.1.2 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. - - -- Runtime Function: int __cmpdi2 (long A, long B) - -- Runtime Function: int __cmpti2 (long long A, long long B) - These functions perform a signed comparison of A and B. If A is - less than B, they return 0; if A is greater than B, they return 2; - and if A and B are equal they return 1. - - -- Runtime Function: int __ucmpdi2 (unsigned long A, unsigned long B) - -- Runtime Function: int __ucmpti2 (unsigned long long A, unsigned long - long B) - These functions perform an unsigned comparison of A and B. If A is - less than B, they return 0; if A is greater than B, they return 2; - and if A and B are equal they return 1. - -4.1.3 Trapping arithmetic functions ------------------------------------ - -The following functions implement trapping arithmetic. These functions -call the libc function 'abort' upon signed arithmetic overflow. - - -- Runtime Function: int __absvsi2 (int A) - -- Runtime Function: long __absvdi2 (long A) - These functions return the absolute value of A. - - -- Runtime Function: int __addvsi3 (int A, int B) - -- Runtime Function: long __addvdi3 (long A, long B) - These functions return the sum of A and B; that is 'A + B'. - - -- Runtime Function: int __mulvsi3 (int A, int B) - -- Runtime Function: long __mulvdi3 (long A, long B) - The functions return the product of A and B; that is 'A * B'. - - -- Runtime Function: int __negvsi2 (int A) - -- Runtime Function: long __negvdi2 (long A) - These functions return the negation of A; that is '-A'. - - -- Runtime Function: int __subvsi3 (int A, int B) - -- Runtime Function: long __subvdi3 (long A, long B) - These functions return the difference between B and A; that is 'A - - B'. - -4.1.4 Bit operations --------------------- - - -- Runtime Function: int __clzsi2 (int A) - -- Runtime Function: int __clzdi2 (long A) - -- Runtime Function: int __clzti2 (long long A) - These functions return the number of leading 0-bits in A, starting - at the most significant bit position. If A is zero, the result is - undefined. - - -- Runtime Function: int __ctzsi2 (int A) - -- Runtime Function: int __ctzdi2 (long A) - -- Runtime Function: int __ctzti2 (long long A) - These functions return the number of trailing 0-bits in A, starting - at the least significant bit position. If A is zero, the result is - undefined. - - -- Runtime Function: int __ffsdi2 (long A) - -- Runtime Function: int __ffsti2 (long long A) - These functions return the index of the least significant 1-bit in - A, or the value zero if A is zero. The least significant bit is - index one. - - -- Runtime Function: int __paritysi2 (int A) - -- Runtime Function: int __paritydi2 (long A) - -- Runtime Function: int __parityti2 (long long A) - These functions return the value zero if the number of bits set in - A is even, and the value one otherwise. - - -- Runtime Function: int __popcountsi2 (int A) - -- Runtime Function: int __popcountdi2 (long A) - -- Runtime Function: int __popcountti2 (long long A) - These functions return the number of bits set in A. - - -- Runtime Function: int32_t __bswapsi2 (int32_t A) - -- Runtime Function: int64_t __bswapdi2 (int64_t A) - These functions return the A byteswapped. - - -File: gccint.info, Node: Soft float library routines, Next: Decimal float library routines, Prev: Integer library routines, Up: Libgcc - -4.2 Routines for floating point emulation -========================================= - -The software floating point library is used on machines which do not -have hardware support for floating point. It is also used whenever -'-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 'DECLARE_LIBRARY_RENAMES' macro (*note -Library Calls::). In this section, the default names are used. - - Presently the library does not support 'XFmode', which is used for -'long double' on some architectures. - -4.2.1 Arithmetic functions --------------------------- - - -- Runtime Function: float __addsf3 (float A, float B) - -- Runtime Function: double __adddf3 (double A, double B) - -- Runtime Function: long double __addtf3 (long double A, long double - B) - -- Runtime Function: long double __addxf3 (long double A, long double - B) - These functions return the sum of A and B. - - -- Runtime Function: float __subsf3 (float A, float B) - -- Runtime Function: double __subdf3 (double A, double B) - -- Runtime Function: long double __subtf3 (long double A, long double - B) - -- Runtime Function: long double __subxf3 (long double A, long double - B) - These functions return the difference between B and A; that is, - A - B. - - -- Runtime Function: float __mulsf3 (float A, float B) - -- Runtime Function: double __muldf3 (double A, double B) - -- Runtime Function: long double __multf3 (long double A, long double - B) - -- Runtime Function: long double __mulxf3 (long double A, long double - B) - These functions return the product of A and B. - - -- Runtime Function: float __divsf3 (float A, float B) - -- Runtime Function: double __divdf3 (double A, double B) - -- Runtime Function: long double __divtf3 (long double A, long double - B) - -- Runtime Function: long double __divxf3 (long double A, long double - B) - These functions return the quotient of A and B; that is, A / B. - - -- Runtime Function: float __negsf2 (float A) - -- Runtime Function: double __negdf2 (double A) - -- Runtime Function: long double __negtf2 (long double A) - -- Runtime Function: long double __negxf2 (long double A) - These functions return the negation of A. They simply flip the - sign bit, so they can produce negative zero and negative NaN. - -4.2.2 Conversion functions --------------------------- - - -- Runtime Function: double __extendsfdf2 (float A) - -- Runtime Function: long double __extendsftf2 (float A) - -- Runtime Function: long double __extendsfxf2 (float A) - -- Runtime Function: long double __extenddftf2 (double A) - -- Runtime Function: long double __extenddfxf2 (double A) - These functions extend A to the wider mode of their return type. - - -- Runtime Function: double __truncxfdf2 (long double A) - -- Runtime Function: double __trunctfdf2 (long double A) - -- Runtime Function: float __truncxfsf2 (long double A) - -- Runtime Function: float __trunctfsf2 (long double A) - -- Runtime Function: float __truncdfsf2 (double A) - These functions truncate A to the narrower mode of their return - type, rounding toward zero. - - -- Runtime Function: int __fixsfsi (float A) - -- Runtime Function: int __fixdfsi (double A) - -- Runtime Function: int __fixtfsi (long double A) - -- Runtime Function: int __fixxfsi (long double A) - These functions convert A to a signed integer, rounding toward - zero. - - -- Runtime Function: long __fixsfdi (float A) - -- Runtime Function: long __fixdfdi (double A) - -- Runtime Function: long __fixtfdi (long double A) - -- Runtime Function: long __fixxfdi (long double A) - These functions convert A to a signed long, rounding toward zero. - - -- Runtime Function: long long __fixsfti (float A) - -- Runtime Function: long long __fixdfti (double A) - -- Runtime Function: long long __fixtfti (long double A) - -- Runtime Function: long long __fixxfti (long double A) - These functions convert A to a signed long long, rounding toward - zero. - - -- Runtime Function: unsigned int __fixunssfsi (float A) - -- Runtime Function: unsigned int __fixunsdfsi (double A) - -- Runtime Function: unsigned int __fixunstfsi (long double A) - -- Runtime Function: unsigned int __fixunsxfsi (long double A) - These functions convert A to an unsigned integer, rounding toward - zero. Negative values all become zero. - - -- Runtime Function: unsigned long __fixunssfdi (float A) - -- Runtime Function: unsigned long __fixunsdfdi (double A) - -- Runtime Function: unsigned long __fixunstfdi (long double A) - -- Runtime Function: unsigned long __fixunsxfdi (long double A) - These functions convert A to an unsigned long, rounding toward - zero. Negative values all become zero. - - -- Runtime Function: unsigned long long __fixunssfti (float A) - -- Runtime Function: unsigned long long __fixunsdfti (double A) - -- Runtime Function: unsigned long long __fixunstfti (long double A) - -- Runtime Function: unsigned long long __fixunsxfti (long double A) - These functions convert A to an unsigned long long, rounding toward - zero. Negative values all become zero. - - -- Runtime Function: float __floatsisf (int I) - -- Runtime Function: double __floatsidf (int I) - -- Runtime Function: long double __floatsitf (int I) - -- Runtime Function: long double __floatsixf (int I) - These functions convert I, a signed integer, to floating point. - - -- Runtime Function: float __floatdisf (long I) - -- Runtime Function: double __floatdidf (long I) - -- Runtime Function: long double __floatditf (long I) - -- Runtime Function: long double __floatdixf (long I) - These functions convert I, a signed long, to floating point. - - -- Runtime Function: float __floattisf (long long I) - -- Runtime Function: double __floattidf (long long I) - -- Runtime Function: long double __floattitf (long long I) - -- Runtime Function: long double __floattixf (long long I) - These functions convert I, a signed long long, to floating point. - - -- Runtime Function: float __floatunsisf (unsigned int I) - -- Runtime Function: double __floatunsidf (unsigned int I) - -- Runtime Function: long double __floatunsitf (unsigned int I) - -- Runtime Function: long double __floatunsixf (unsigned int I) - These functions convert I, an unsigned integer, to floating point. - - -- Runtime Function: float __floatundisf (unsigned long I) - -- Runtime Function: double __floatundidf (unsigned long I) - -- Runtime Function: long double __floatunditf (unsigned long I) - -- Runtime Function: long double __floatundixf (unsigned long I) - These functions convert I, an unsigned long, to floating point. - - -- Runtime Function: float __floatuntisf (unsigned long long I) - -- Runtime Function: double __floatuntidf (unsigned long long I) - -- Runtime Function: long double __floatuntitf (unsigned long long I) - -- Runtime Function: long double __floatuntixf (unsigned long long I) - These functions convert I, an unsigned long long, to floating - point. - -4.2.3 Comparison functions --------------------------- - -There are two sets of basic comparison functions. - - -- Runtime Function: int __cmpsf2 (float A, float B) - -- Runtime Function: int __cmpdf2 (double A, double B) - -- Runtime Function: int __cmptf2 (long double A, long double B) - These functions calculate a <=> b. That is, if A is less than B, - they return -1; if A is greater than B, they return 1; and if A and - 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. - - -- Runtime Function: int __unordsf2 (float A, float B) - -- Runtime Function: int __unorddf2 (double A, double B) - -- Runtime Function: int __unordtf2 (long double A, long double B) - These functions return a nonzero value if either argument is NaN, - otherwise 0. - - 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 - - if (__unordXf2 (a, b)) - return E; - return __cmpXf2 (a, b); - -where 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. - - -- Runtime Function: int __eqsf2 (float A, float B) - -- Runtime Function: int __eqdf2 (double A, double B) - -- Runtime Function: int __eqtf2 (long double A, long double B) - These functions return zero if neither argument is NaN, and A and B - are equal. - - -- Runtime Function: int __nesf2 (float A, float B) - -- Runtime Function: int __nedf2 (double A, double B) - -- Runtime Function: int __netf2 (long double A, long double B) - These functions return a nonzero value if either argument is NaN, - or if A and B are unequal. - - -- Runtime Function: int __gesf2 (float A, float B) - -- Runtime Function: int __gedf2 (double A, double B) - -- Runtime Function: int __getf2 (long double A, long double B) - These functions return a value greater than or equal to zero if - neither argument is NaN, and A is greater than or equal to B. - - -- Runtime Function: int __ltsf2 (float A, float B) - -- Runtime Function: int __ltdf2 (double A, double B) - -- Runtime Function: int __lttf2 (long double A, long double B) - These functions return a value less than zero if neither argument - is NaN, and A is strictly less than B. - - -- Runtime Function: int __lesf2 (float A, float B) - -- Runtime Function: int __ledf2 (double A, double B) - -- Runtime Function: int __letf2 (long double A, long double B) - These functions return a value less than or equal to zero if - neither argument is NaN, and A is less than or equal to B. - - -- Runtime Function: int __gtsf2 (float A, float B) - -- Runtime Function: int __gtdf2 (double A, double B) - -- Runtime Function: int __gttf2 (long double A, long double B) - These functions return a value greater than zero if neither - argument is NaN, and A is strictly greater than B. - -4.2.4 Other floating-point functions ------------------------------------- - - -- Runtime Function: float __powisf2 (float A, int B) - -- Runtime Function: double __powidf2 (double A, int B) - -- Runtime Function: long double __powitf2 (long double A, int B) - -- Runtime Function: long double __powixf2 (long double A, int B) - These functions convert raise A to the power B. - - -- Runtime Function: complex float __mulsc3 (float A, float B, float C, - float D) - -- Runtime Function: complex double __muldc3 (double A, double B, - double C, double D) - -- Runtime Function: complex long double __multc3 (long double A, long - double B, long double C, long double D) - -- Runtime Function: complex long double __mulxc3 (long double A, long - double B, long double C, long double D) - These functions return the product of A + iB and C + iD, following - the rules of C99 Annex G. - - -- Runtime Function: complex float __divsc3 (float A, float B, float C, - float D) - -- Runtime Function: complex double __divdc3 (double A, double B, - double C, double D) - -- Runtime Function: complex long double __divtc3 (long double A, long - double B, long double C, long double D) - -- Runtime Function: complex long double __divxc3 (long double A, long - double B, long double C, long double D) - These functions return the quotient of A + iB and C + iD (i.e., (A - + iB) / (C + iD)), following the rules of C99 Annex G. - - -File: gccint.info, Node: Decimal float library routines, Next: Fixed-point fractional library routines, Prev: Soft float library routines, Up: Libgcc - -4.3 Routines for decimal floating point emulation -================================================= - -The software decimal floating point library implements IEEE 754-2008 -decimal floating point arithmetic and is only activated on selected -targets. - - The software decimal floating point library supports either DPD -(Densely Packed Decimal) or BID (Binary Integer Decimal) encoding as -selected at configure time. - -4.3.1 Arithmetic functions --------------------------- - - -- Runtime Function: _Decimal32 __dpd_addsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal32 __bid_addsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal64 __dpd_adddd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal64 __bid_adddd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal128 __dpd_addtd3 (_Decimal128 A, - _Decimal128 B) - -- Runtime Function: _Decimal128 __bid_addtd3 (_Decimal128 A, - _Decimal128 B) - These functions return the sum of A and B. - - -- Runtime Function: _Decimal32 __dpd_subsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal32 __bid_subsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal64 __dpd_subdd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal64 __bid_subdd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal128 __dpd_subtd3 (_Decimal128 A, - _Decimal128 B) - -- Runtime Function: _Decimal128 __bid_subtd3 (_Decimal128 A, - _Decimal128 B) - These functions return the difference between B and A; that is, - A - B. - - -- Runtime Function: _Decimal32 __dpd_mulsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal32 __bid_mulsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal64 __dpd_muldd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal64 __bid_muldd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal128 __dpd_multd3 (_Decimal128 A, - _Decimal128 B) - -- Runtime Function: _Decimal128 __bid_multd3 (_Decimal128 A, - _Decimal128 B) - These functions return the product of A and B. - - -- Runtime Function: _Decimal32 __dpd_divsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal32 __bid_divsd3 (_Decimal32 A, _Decimal32 - B) - -- Runtime Function: _Decimal64 __dpd_divdd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal64 __bid_divdd3 (_Decimal64 A, _Decimal64 - B) - -- Runtime Function: _Decimal128 __dpd_divtd3 (_Decimal128 A, - _Decimal128 B) - -- Runtime Function: _Decimal128 __bid_divtd3 (_Decimal128 A, - _Decimal128 B) - These functions return the quotient of A and B; that is, A / B. - - -- Runtime Function: _Decimal32 __dpd_negsd2 (_Decimal32 A) - -- Runtime Function: _Decimal32 __bid_negsd2 (_Decimal32 A) - -- Runtime Function: _Decimal64 __dpd_negdd2 (_Decimal64 A) - -- Runtime Function: _Decimal64 __bid_negdd2 (_Decimal64 A) - -- Runtime Function: _Decimal128 __dpd_negtd2 (_Decimal128 A) - -- Runtime Function: _Decimal128 __bid_negtd2 (_Decimal128 A) - These functions return the negation of A. They simply flip the - sign bit, so they can produce negative zero and negative NaN. - -4.3.2 Conversion functions --------------------------- - - -- Runtime Function: _Decimal64 __dpd_extendsddd2 (_Decimal32 A) - -- Runtime Function: _Decimal64 __bid_extendsddd2 (_Decimal32 A) - -- Runtime Function: _Decimal128 __dpd_extendsdtd2 (_Decimal32 A) - -- Runtime Function: _Decimal128 __bid_extendsdtd2 (_Decimal32 A) - -- Runtime Function: _Decimal128 __dpd_extendddtd2 (_Decimal64 A) - -- Runtime Function: _Decimal128 __bid_extendddtd2 (_Decimal64 A) - -- Runtime Function: _Decimal32 __dpd_truncddsd2 (_Decimal64 A) - -- Runtime Function: _Decimal32 __bid_truncddsd2 (_Decimal64 A) - -- Runtime Function: _Decimal32 __dpd_trunctdsd2 (_Decimal128 A) - -- Runtime Function: _Decimal32 __bid_trunctdsd2 (_Decimal128 A) - -- Runtime Function: _Decimal64 __dpd_trunctddd2 (_Decimal128 A) - -- Runtime Function: _Decimal64 __bid_trunctddd2 (_Decimal128 A) - These functions convert the value A from one decimal floating type - to another. - - -- Runtime Function: _Decimal64 __dpd_extendsfdd (float A) - -- Runtime Function: _Decimal64 __bid_extendsfdd (float A) - -- Runtime Function: _Decimal128 __dpd_extendsftd (float A) - -- Runtime Function: _Decimal128 __bid_extendsftd (float A) - -- Runtime Function: _Decimal128 __dpd_extenddftd (double A) - -- Runtime Function: _Decimal128 __bid_extenddftd (double A) - -- Runtime Function: _Decimal128 __dpd_extendxftd (long double A) - -- Runtime Function: _Decimal128 __bid_extendxftd (long double A) - -- Runtime Function: _Decimal32 __dpd_truncdfsd (double A) - -- Runtime Function: _Decimal32 __bid_truncdfsd (double A) - -- Runtime Function: _Decimal32 __dpd_truncxfsd (long double A) - -- Runtime Function: _Decimal32 __bid_truncxfsd (long double A) - -- Runtime Function: _Decimal32 __dpd_trunctfsd (long double A) - -- Runtime Function: _Decimal32 __bid_trunctfsd (long double A) - -- Runtime Function: _Decimal64 __dpd_truncxfdd (long double A) - -- Runtime Function: _Decimal64 __bid_truncxfdd (long double A) - -- Runtime Function: _Decimal64 __dpd_trunctfdd (long double A) - -- Runtime Function: _Decimal64 __bid_trunctfdd (long double A) - These functions convert the value of A from a binary floating type - to a decimal floating type of a different size. - - -- Runtime Function: float __dpd_truncddsf (_Decimal64 A) - -- Runtime Function: float __bid_truncddsf (_Decimal64 A) - -- Runtime Function: float __dpd_trunctdsf (_Decimal128 A) - -- Runtime Function: float __bid_trunctdsf (_Decimal128 A) - -- Runtime Function: double __dpd_extendsddf (_Decimal32 A) - -- Runtime Function: double __bid_extendsddf (_Decimal32 A) - -- Runtime Function: double __dpd_trunctddf (_Decimal128 A) - -- Runtime Function: double __bid_trunctddf (_Decimal128 A) - -- Runtime Function: long double __dpd_extendsdxf (_Decimal32 A) - -- Runtime Function: long double __bid_extendsdxf (_Decimal32 A) - -- Runtime Function: long double __dpd_extendddxf (_Decimal64 A) - -- Runtime Function: long double __bid_extendddxf (_Decimal64 A) - -- Runtime Function: long double __dpd_trunctdxf (_Decimal128 A) - -- Runtime Function: long double __bid_trunctdxf (_Decimal128 A) - -- Runtime Function: long double __dpd_extendsdtf (_Decimal32 A) - -- Runtime Function: long double __bid_extendsdtf (_Decimal32 A) - -- Runtime Function: long double __dpd_extendddtf (_Decimal64 A) - -- Runtime Function: long double __bid_extendddtf (_Decimal64 A) - These functions convert the value of A from a decimal floating type - to a binary floating type of a different size. - - -- Runtime Function: _Decimal32 __dpd_extendsfsd (float A) - -- Runtime Function: _Decimal32 __bid_extendsfsd (float A) - -- Runtime Function: _Decimal64 __dpd_extenddfdd (double A) - -- Runtime Function: _Decimal64 __bid_extenddfdd (double A) - -- Runtime Function: _Decimal128 __dpd_extendtftd (long double A) - -- Runtime Function: _Decimal128 __bid_extendtftd (long double A) - -- Runtime Function: float __dpd_truncsdsf (_Decimal32 A) - -- Runtime Function: float __bid_truncsdsf (_Decimal32 A) - -- Runtime Function: double __dpd_truncdddf (_Decimal64 A) - -- Runtime Function: double __bid_truncdddf (_Decimal64 A) - -- Runtime Function: long double __dpd_trunctdtf (_Decimal128 A) - -- Runtime Function: long double __bid_trunctdtf (_Decimal128 A) - These functions convert the value of A between decimal and binary - floating types of the same size. - - -- Runtime Function: int __dpd_fixsdsi (_Decimal32 A) - -- Runtime Function: int __bid_fixsdsi (_Decimal32 A) - -- Runtime Function: int __dpd_fixddsi (_Decimal64 A) - -- Runtime Function: int __bid_fixddsi (_Decimal64 A) - -- Runtime Function: int __dpd_fixtdsi (_Decimal128 A) - -- Runtime Function: int __bid_fixtdsi (_Decimal128 A) - These functions convert A to a signed integer. - - -- Runtime Function: long __dpd_fixsddi (_Decimal32 A) - -- Runtime Function: long __bid_fixsddi (_Decimal32 A) - -- Runtime Function: long __dpd_fixdddi (_Decimal64 A) - -- Runtime Function: long __bid_fixdddi (_Decimal64 A) - -- Runtime Function: long __dpd_fixtddi (_Decimal128 A) - -- Runtime Function: long __bid_fixtddi (_Decimal128 A) - These functions convert A to a signed long. - - -- Runtime Function: unsigned int __dpd_fixunssdsi (_Decimal32 A) - -- Runtime Function: unsigned int __bid_fixunssdsi (_Decimal32 A) - -- Runtime Function: unsigned int __dpd_fixunsddsi (_Decimal64 A) - -- Runtime Function: unsigned int __bid_fixunsddsi (_Decimal64 A) - -- Runtime Function: unsigned int __dpd_fixunstdsi (_Decimal128 A) - -- Runtime Function: unsigned int __bid_fixunstdsi (_Decimal128 A) - These functions convert A to an unsigned integer. Negative values - all become zero. - - -- Runtime Function: unsigned long __dpd_fixunssddi (_Decimal32 A) - -- Runtime Function: unsigned long __bid_fixunssddi (_Decimal32 A) - -- Runtime Function: unsigned long __dpd_fixunsdddi (_Decimal64 A) - -- Runtime Function: unsigned long __bid_fixunsdddi (_Decimal64 A) - -- Runtime Function: unsigned long __dpd_fixunstddi (_Decimal128 A) - -- Runtime Function: unsigned long __bid_fixunstddi (_Decimal128 A) - These functions convert A to an unsigned long. Negative values all - become zero. - - -- Runtime Function: _Decimal32 __dpd_floatsisd (int I) - -- Runtime Function: _Decimal32 __bid_floatsisd (int I) - -- Runtime Function: _Decimal64 __dpd_floatsidd (int I) - -- Runtime Function: _Decimal64 __bid_floatsidd (int I) - -- Runtime Function: _Decimal128 __dpd_floatsitd (int I) - -- Runtime Function: _Decimal128 __bid_floatsitd (int I) - These functions convert I, a signed integer, to decimal floating - point. - - -- Runtime Function: _Decimal32 __dpd_floatdisd (long I) - -- Runtime Function: _Decimal32 __bid_floatdisd (long I) - -- Runtime Function: _Decimal64 __dpd_floatdidd (long I) - -- Runtime Function: _Decimal64 __bid_floatdidd (long I) - -- Runtime Function: _Decimal128 __dpd_floatditd (long I) - -- Runtime Function: _Decimal128 __bid_floatditd (long I) - These functions convert I, a signed long, to decimal floating - point. - - -- Runtime Function: _Decimal32 __dpd_floatunssisd (unsigned int I) - -- Runtime Function: _Decimal32 __bid_floatunssisd (unsigned int I) - -- Runtime Function: _Decimal64 __dpd_floatunssidd (unsigned int I) - -- Runtime Function: _Decimal64 __bid_floatunssidd (unsigned int I) - -- Runtime Function: _Decimal128 __dpd_floatunssitd (unsigned int I) - -- Runtime Function: _Decimal128 __bid_floatunssitd (unsigned int I) - These functions convert I, an unsigned integer, to decimal floating - point. - - -- Runtime Function: _Decimal32 __dpd_floatunsdisd (unsigned long I) - -- Runtime Function: _Decimal32 __bid_floatunsdisd (unsigned long I) - -- Runtime Function: _Decimal64 __dpd_floatunsdidd (unsigned long I) - -- Runtime Function: _Decimal64 __bid_floatunsdidd (unsigned long I) - -- Runtime Function: _Decimal128 __dpd_floatunsditd (unsigned long I) - -- Runtime Function: _Decimal128 __bid_floatunsditd (unsigned long I) - These functions convert I, an unsigned long, to decimal floating - point. - -4.3.3 Comparison functions --------------------------- - - -- Runtime Function: int __dpd_unordsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_unordsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_unorddd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_unorddd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_unordtd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_unordtd2 (_Decimal128 A, _Decimal128 B) - These functions return a nonzero value if either argument is NaN, - otherwise 0. - - 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 - - if (__bid_unordXd2 (a, b)) - return E; - return __bid_cmpXd2 (a, b); - -where 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. - - -- Runtime Function: int __dpd_eqsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_eqsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_eqdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_eqdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_eqtd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_eqtd2 (_Decimal128 A, _Decimal128 B) - These functions return zero if neither argument is NaN, and A and B - are equal. - - -- Runtime Function: int __dpd_nesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_nesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_nedd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_nedd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_netd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_netd2 (_Decimal128 A, _Decimal128 B) - These functions return a nonzero value if either argument is NaN, - or if A and B are unequal. - - -- Runtime Function: int __dpd_gesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_gesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_gedd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_gedd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_getd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_getd2 (_Decimal128 A, _Decimal128 B) - These functions return a value greater than or equal to zero if - neither argument is NaN, and A is greater than or equal to B. - - -- Runtime Function: int __dpd_ltsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_ltsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_ltdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_ltdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_lttd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_lttd2 (_Decimal128 A, _Decimal128 B) - These functions return a value less than zero if neither argument - is NaN, and A is strictly less than B. - - -- Runtime Function: int __dpd_lesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_lesd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_ledd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_ledd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_letd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_letd2 (_Decimal128 A, _Decimal128 B) - These functions return a value less than or equal to zero if - neither argument is NaN, and A is less than or equal to B. - - -- Runtime Function: int __dpd_gtsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __bid_gtsd2 (_Decimal32 A, _Decimal32 B) - -- Runtime Function: int __dpd_gtdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __bid_gtdd2 (_Decimal64 A, _Decimal64 B) - -- Runtime Function: int __dpd_gttd2 (_Decimal128 A, _Decimal128 B) - -- Runtime Function: int __bid_gttd2 (_Decimal128 A, _Decimal128 B) - These functions return a value greater than zero if neither - argument is NaN, and A is strictly greater than B. - - -File: gccint.info, Node: Fixed-point fractional library routines, Next: Exception handling routines, Prev: Decimal float library routines, Up: Libgcc - -4.4 Routines for fixed-point fractional emulation -================================================= - -The software fixed-point library implements fixed-point fractional -arithmetic, and is only activated on selected targets. - - For ease of comprehension 'fract' is an alias for the '_Fract' type, -'accum' an alias for '_Accum', and 'sat' an alias for '_Sat'. - - For illustrative purposes, in this section the fixed-point fractional -type 'short fract' is assumed to correspond to machine mode 'QQmode'; -'unsigned short fract' to 'UQQmode'; 'fract' to 'HQmode'; -'unsigned fract' to 'UHQmode'; 'long fract' to 'SQmode'; -'unsigned long fract' to 'USQmode'; 'long long fract' to 'DQmode'; and -'unsigned long long fract' to 'UDQmode'. Similarly the fixed-point -accumulator type 'short accum' corresponds to 'HAmode'; -'unsigned short accum' to 'UHAmode'; 'accum' to 'SAmode'; -'unsigned accum' to 'USAmode'; 'long accum' to 'DAmode'; -'unsigned long accum' to 'UDAmode'; 'long long accum' to 'TAmode'; and -'unsigned long long accum' to 'UTAmode'. - -4.4.1 Arithmetic functions --------------------------- - - -- Runtime Function: short fract __addqq3 (short fract A, short fract - B) - -- Runtime Function: fract __addhq3 (fract A, fract B) - -- Runtime Function: long fract __addsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __adddq3 (long long fract A, long - long fract B) - -- Runtime Function: unsigned short fract __adduqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __adduhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __addusq3 (unsigned long fract - A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __addudq3 (unsigned long - long fract A, unsigned long long fract B) - -- Runtime Function: short accum __addha3 (short accum A, short accum - B) - -- Runtime Function: accum __addsa3 (accum A, accum B) - -- Runtime Function: long accum __addda3 (long accum A, long accum B) - -- Runtime Function: long long accum __addta3 (long long accum A, long - long accum B) - -- Runtime Function: unsigned short accum __adduha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __addusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __adduda3 (unsigned long accum - A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __adduta3 (unsigned long - long accum A, unsigned long long accum B) - These functions return the sum of A and B. - - -- Runtime Function: short fract __ssaddqq3 (short fract A, short fract - B) - -- Runtime Function: fract __ssaddhq3 (fract A, fract B) - -- Runtime Function: long fract __ssaddsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __ssadddq3 (long long fract A, - long long fract B) - -- Runtime Function: short accum __ssaddha3 (short accum A, short accum - B) - -- Runtime Function: accum __ssaddsa3 (accum A, accum B) - -- Runtime Function: long accum __ssaddda3 (long accum A, long accum B) - -- Runtime Function: long long accum __ssaddta3 (long long accum A, - long long accum B) - These functions return the sum of A and B with signed saturation. - - -- Runtime Function: unsigned short fract __usadduqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __usadduhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __usaddusq3 (unsigned long - fract A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __usaddudq3 (unsigned - long long fract A, unsigned long long fract B) - -- Runtime Function: unsigned short accum __usadduha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __usaddusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __usadduda3 (unsigned long - accum A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __usadduta3 (unsigned - long long accum A, unsigned long long accum B) - These functions return the sum of A and B with unsigned saturation. - - -- Runtime Function: short fract __subqq3 (short fract A, short fract - B) - -- Runtime Function: fract __subhq3 (fract A, fract B) - -- Runtime Function: long fract __subsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __subdq3 (long long fract A, long - long fract B) - -- Runtime Function: unsigned short fract __subuqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __subuhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __subusq3 (unsigned long fract - A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __subudq3 (unsigned long - long fract A, unsigned long long fract B) - -- Runtime Function: short accum __subha3 (short accum A, short accum - B) - -- Runtime Function: accum __subsa3 (accum A, accum B) - -- Runtime Function: long accum __subda3 (long accum A, long accum B) - -- Runtime Function: long long accum __subta3 (long long accum A, long - long accum B) - -- Runtime Function: unsigned short accum __subuha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __subusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __subuda3 (unsigned long accum - A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __subuta3 (unsigned long - long accum A, unsigned long long accum B) - These functions return the difference of A and B; that is, 'A - B'. - - -- Runtime Function: short fract __sssubqq3 (short fract A, short fract - B) - -- Runtime Function: fract __sssubhq3 (fract A, fract B) - -- Runtime Function: long fract __sssubsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __sssubdq3 (long long fract A, - long long fract B) - -- Runtime Function: short accum __sssubha3 (short accum A, short accum - B) - -- Runtime Function: accum __sssubsa3 (accum A, accum B) - -- Runtime Function: long accum __sssubda3 (long accum A, long accum B) - -- Runtime Function: long long accum __sssubta3 (long long accum A, - long long accum B) - These functions return the difference of A and B with signed - saturation; that is, 'A - B'. - - -- Runtime Function: unsigned short fract __ussubuqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __ussubuhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __ussubusq3 (unsigned long - fract A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __ussubudq3 (unsigned - long long fract A, unsigned long long fract B) - -- Runtime Function: unsigned short accum __ussubuha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __ussubusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __ussubuda3 (unsigned long - accum A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __ussubuta3 (unsigned - long long accum A, unsigned long long accum B) - These functions return the difference of A and B with unsigned - saturation; that is, 'A - B'. - - -- Runtime Function: short fract __mulqq3 (short fract A, short fract - B) - -- Runtime Function: fract __mulhq3 (fract A, fract B) - -- Runtime Function: long fract __mulsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __muldq3 (long long fract A, long - long fract B) - -- Runtime Function: unsigned short fract __muluqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __muluhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __mulusq3 (unsigned long fract - A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __muludq3 (unsigned long - long fract A, unsigned long long fract B) - -- Runtime Function: short accum __mulha3 (short accum A, short accum - B) - -- Runtime Function: accum __mulsa3 (accum A, accum B) - -- Runtime Function: long accum __mulda3 (long accum A, long accum B) - -- Runtime Function: long long accum __multa3 (long long accum A, long - long accum B) - -- Runtime Function: unsigned short accum __muluha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __mulusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __muluda3 (unsigned long accum - A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __muluta3 (unsigned long - long accum A, unsigned long long accum B) - These functions return the product of A and B. - - -- Runtime Function: short fract __ssmulqq3 (short fract A, short fract - B) - -- Runtime Function: fract __ssmulhq3 (fract A, fract B) - -- Runtime Function: long fract __ssmulsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __ssmuldq3 (long long fract A, - long long fract B) - -- Runtime Function: short accum __ssmulha3 (short accum A, short accum - B) - -- Runtime Function: accum __ssmulsa3 (accum A, accum B) - -- Runtime Function: long accum __ssmulda3 (long accum A, long accum B) - -- Runtime Function: long long accum __ssmulta3 (long long accum A, - long long accum B) - These functions return the product of A and B with signed - saturation. - - -- Runtime Function: unsigned short fract __usmuluqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __usmuluhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __usmulusq3 (unsigned long - fract A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __usmuludq3 (unsigned - long long fract A, unsigned long long fract B) - -- Runtime Function: unsigned short accum __usmuluha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __usmulusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __usmuluda3 (unsigned long - accum A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __usmuluta3 (unsigned - long long accum A, unsigned long long accum B) - These functions return the product of A and B with unsigned - saturation. - - -- Runtime Function: short fract __divqq3 (short fract A, short fract - B) - -- Runtime Function: fract __divhq3 (fract A, fract B) - -- Runtime Function: long fract __divsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __divdq3 (long long fract A, long - long fract B) - -- Runtime Function: short accum __divha3 (short accum A, short accum - B) - -- Runtime Function: accum __divsa3 (accum A, accum B) - -- Runtime Function: long accum __divda3 (long accum A, long accum B) - -- Runtime Function: long long accum __divta3 (long long accum A, long - long accum B) - These functions return the quotient of the signed division of A and - B. - - -- Runtime Function: unsigned short fract __udivuqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __udivuhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __udivusq3 (unsigned long - fract A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __udivudq3 (unsigned long - long fract A, unsigned long long fract B) - -- Runtime Function: unsigned short accum __udivuha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __udivusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __udivuda3 (unsigned long - accum A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __udivuta3 (unsigned long - long accum A, unsigned long long accum B) - These functions return the quotient of the unsigned division of A - and B. - - -- Runtime Function: short fract __ssdivqq3 (short fract A, short fract - B) - -- Runtime Function: fract __ssdivhq3 (fract A, fract B) - -- Runtime Function: long fract __ssdivsq3 (long fract A, long fract B) - -- Runtime Function: long long fract __ssdivdq3 (long long fract A, - long long fract B) - -- Runtime Function: short accum __ssdivha3 (short accum A, short accum - B) - -- Runtime Function: accum __ssdivsa3 (accum A, accum B) - -- Runtime Function: long accum __ssdivda3 (long accum A, long accum B) - -- Runtime Function: long long accum __ssdivta3 (long long accum A, - long long accum B) - These functions return the quotient of the signed division of A and - B with signed saturation. - - -- Runtime Function: unsigned short fract __usdivuqq3 (unsigned short - fract A, unsigned short fract B) - -- Runtime Function: unsigned fract __usdivuhq3 (unsigned fract A, - unsigned fract B) - -- Runtime Function: unsigned long fract __usdivusq3 (unsigned long - fract A, unsigned long fract B) - -- Runtime Function: unsigned long long fract __usdivudq3 (unsigned - long long fract A, unsigned long long fract B) - -- Runtime Function: unsigned short accum __usdivuha3 (unsigned short - accum A, unsigned short accum B) - -- Runtime Function: unsigned accum __usdivusa3 (unsigned accum A, - unsigned accum B) - -- Runtime Function: unsigned long accum __usdivuda3 (unsigned long - accum A, unsigned long accum B) - -- Runtime Function: unsigned long long accum __usdivuta3 (unsigned - long long accum A, unsigned long long accum B) - These functions return the quotient of the unsigned division of A - and B with unsigned saturation. - - -- Runtime Function: short fract __negqq2 (short fract A) - -- Runtime Function: fract __neghq2 (fract A) - -- Runtime Function: long fract __negsq2 (long fract A) - -- Runtime Function: long long fract __negdq2 (long long fract A) - -- Runtime Function: unsigned short fract __neguqq2 (unsigned short - fract A) - -- Runtime Function: unsigned fract __neguhq2 (unsigned fract A) - -- Runtime Function: unsigned long fract __negusq2 (unsigned long fract - A) - -- Runtime Function: unsigned long long fract __negudq2 (unsigned long - long fract A) - -- Runtime Function: short accum __negha2 (short accum A) - -- Runtime Function: accum __negsa2 (accum A) - -- Runtime Function: long accum __negda2 (long accum A) - -- Runtime Function: long long accum __negta2 (long long accum A) - -- Runtime Function: unsigned short accum __neguha2 (unsigned short - accum A) - -- Runtime Function: unsigned accum __negusa2 (unsigned accum A) - -- Runtime Function: unsigned long accum __neguda2 (unsigned long accum - A) - -- Runtime Function: unsigned long long accum __neguta2 (unsigned long - long accum A) - These functions return the negation of A. - - -- Runtime Function: short fract __ssnegqq2 (short fract A) - -- Runtime Function: fract __ssneghq2 (fract A) - -- Runtime Function: long fract __ssnegsq2 (long fract A) - -- Runtime Function: long long fract __ssnegdq2 (long long fract A) - -- Runtime Function: short accum __ssnegha2 (short accum A) - -- Runtime Function: accum __ssnegsa2 (accum A) - -- Runtime Function: long accum __ssnegda2 (long accum A) - -- Runtime Function: long long accum __ssnegta2 (long long accum A) - These functions return the negation of A with signed saturation. - - -- Runtime Function: unsigned short fract __usneguqq2 (unsigned short - fract A) - -- Runtime Function: unsigned fract __usneguhq2 (unsigned fract A) - -- Runtime Function: unsigned long fract __usnegusq2 (unsigned long - fract A) - -- Runtime Function: unsigned long long fract __usnegudq2 (unsigned - long long fract A) - -- Runtime Function: unsigned short accum __usneguha2 (unsigned short - accum A) - -- Runtime Function: unsigned accum __usnegusa2 (unsigned accum A) - -- Runtime Function: unsigned long accum __usneguda2 (unsigned long - accum A) - -- Runtime Function: unsigned long long accum __usneguta2 (unsigned - long long accum A) - These functions return the negation of A with unsigned saturation. - - -- Runtime Function: short fract __ashlqq3 (short fract A, int B) - -- Runtime Function: fract __ashlhq3 (fract A, int B) - -- Runtime Function: long fract __ashlsq3 (long fract A, int B) - -- Runtime Function: long long fract __ashldq3 (long long fract A, int - B) - -- Runtime Function: unsigned short fract __ashluqq3 (unsigned short - fract A, int B) - -- Runtime Function: unsigned fract __ashluhq3 (unsigned fract A, int - B) - -- Runtime Function: unsigned long fract __ashlusq3 (unsigned long - fract A, int B) - -- Runtime Function: unsigned long long fract __ashludq3 (unsigned long - long fract A, int B) - -- Runtime Function: short accum __ashlha3 (short accum A, int B) - -- Runtime Function: accum __ashlsa3 (accum A, int B) - -- Runtime Function: long accum __ashlda3 (long accum A, int B) - -- Runtime Function: long long accum __ashlta3 (long long accum A, int - B) - -- Runtime Function: unsigned short accum __ashluha3 (unsigned short - accum A, int B) - -- Runtime Function: unsigned accum __ashlusa3 (unsigned accum A, int - B) - -- Runtime Function: unsigned long accum __ashluda3 (unsigned long - accum A, int B) - -- Runtime Function: unsigned long long accum __ashluta3 (unsigned long - long accum A, int B) - These functions return the result of shifting A left by B bits. - - -- Runtime Function: short fract __ashrqq3 (short fract A, int B) - -- Runtime Function: fract __ashrhq3 (fract A, int B) - -- Runtime Function: long fract __ashrsq3 (long fract A, int B) - -- Runtime Function: long long fract __ashrdq3 (long long fract A, int - B) - -- Runtime Function: short accum __ashrha3 (short accum A, int B) - -- Runtime Function: accum __ashrsa3 (accum A, int B) - -- Runtime Function: long accum __ashrda3 (long accum A, int B) - -- Runtime Function: long long accum __ashrta3 (long long accum A, int - B) - These functions return the result of arithmetically shifting A - right by B bits. - - -- Runtime Function: unsigned short fract __lshruqq3 (unsigned short - fract A, int B) - -- Runtime Function: unsigned fract __lshruhq3 (unsigned fract A, int - B) - -- Runtime Function: unsigned long fract __lshrusq3 (unsigned long - fract A, int B) - -- Runtime Function: unsigned long long fract __lshrudq3 (unsigned long - long fract A, int B) - -- Runtime Function: unsigned short accum __lshruha3 (unsigned short - accum A, int B) - -- Runtime Function: unsigned accum __lshrusa3 (unsigned accum A, int - B) - -- Runtime Function: unsigned long accum __lshruda3 (unsigned long - accum A, int B) - -- Runtime Function: unsigned long long accum __lshruta3 (unsigned long - long accum A, int B) - These functions return the result of logically shifting A right by - B bits. - - -- Runtime Function: fract __ssashlhq3 (fract A, int B) - -- Runtime Function: long fract __ssashlsq3 (long fract A, int B) - -- Runtime Function: long long fract __ssashldq3 (long long fract A, - int B) - -- Runtime Function: short accum __ssashlha3 (short accum A, int B) - -- Runtime Function: accum __ssashlsa3 (accum A, int B) - -- Runtime Function: long accum __ssashlda3 (long accum A, int B) - -- Runtime Function: long long accum __ssashlta3 (long long accum A, - int B) - These functions return the result of shifting A left by B bits with - signed saturation. - - -- Runtime Function: unsigned short fract __usashluqq3 (unsigned short - fract A, int B) - -- Runtime Function: unsigned fract __usashluhq3 (unsigned fract A, int - B) - -- Runtime Function: unsigned long fract __usashlusq3 (unsigned long - fract A, int B) - -- Runtime Function: unsigned long long fract __usashludq3 (unsigned - long long fract A, int B) - -- Runtime Function: unsigned short accum __usashluha3 (unsigned short - accum A, int B) - -- Runtime Function: unsigned accum __usashlusa3 (unsigned accum A, int - B) - -- Runtime Function: unsigned long accum __usashluda3 (unsigned long - accum A, int B) - -- Runtime Function: unsigned long long accum __usashluta3 (unsigned - long long accum A, int B) - These functions return the result of shifting A left by B bits with - unsigned saturation. - -4.4.2 Comparison functions --------------------------- - -The following functions implement fixed-point 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. - - -- Runtime Function: int __cmpqq2 (short fract A, short fract B) - -- Runtime Function: int __cmphq2 (fract A, fract B) - -- Runtime Function: int __cmpsq2 (long fract A, long fract B) - -- Runtime Function: int __cmpdq2 (long long fract A, long long fract - B) - -- Runtime Function: int __cmpuqq2 (unsigned short fract A, unsigned - short fract B) - -- Runtime Function: int __cmpuhq2 (unsigned fract A, unsigned fract B) - -- Runtime Function: int __cmpusq2 (unsigned long fract A, unsigned - long fract B) - -- Runtime Function: int __cmpudq2 (unsigned long long fract A, - unsigned long long fract B) - -- Runtime Function: int __cmpha2 (short accum A, short accum B) - -- Runtime Function: int __cmpsa2 (accum A, accum B) - -- Runtime Function: int __cmpda2 (long accum A, long accum B) - -- Runtime Function: int __cmpta2 (long long accum A, long long accum - B) - -- Runtime Function: int __cmpuha2 (unsigned short accum A, unsigned - short accum B) - -- Runtime Function: int __cmpusa2 (unsigned accum A, unsigned accum B) - -- Runtime Function: int __cmpuda2 (unsigned long accum A, unsigned - long accum B) - -- Runtime Function: int __cmputa2 (unsigned long long accum A, - unsigned long long accum B) - These functions perform a signed or unsigned comparison of A and B - (depending on the selected machine mode). If A is less than B, - they return 0; if A is greater than B, they return 2; and if A and - B are equal they return 1. - -4.4.3 Conversion functions --------------------------- - - -- Runtime Function: fract __fractqqhq2 (short fract A) - -- Runtime Function: long fract __fractqqsq2 (short fract A) - -- Runtime Function: long long fract __fractqqdq2 (short fract A) - -- Runtime Function: short accum __fractqqha (short fract A) - -- Runtime Function: accum __fractqqsa (short fract A) - -- Runtime Function: long accum __fractqqda (short fract A) - -- Runtime Function: long long accum __fractqqta (short fract A) - -- Runtime Function: unsigned short fract __fractqquqq (short fract A) - -- Runtime Function: unsigned fract __fractqquhq (short fract A) - -- Runtime Function: unsigned long fract __fractqqusq (short fract A) - -- Runtime Function: unsigned long long fract __fractqqudq (short fract - A) - -- Runtime Function: unsigned short accum __fractqquha (short fract A) - -- Runtime Function: unsigned accum __fractqqusa (short fract A) - -- Runtime Function: unsigned long accum __fractqquda (short fract A) - -- Runtime Function: unsigned long long accum __fractqquta (short fract - A) - -- Runtime Function: signed char __fractqqqi (short fract A) - -- Runtime Function: short __fractqqhi (short fract A) - -- Runtime Function: int __fractqqsi (short fract A) - -- Runtime Function: long __fractqqdi (short fract A) - -- Runtime Function: long long __fractqqti (short fract A) - -- Runtime Function: float __fractqqsf (short fract A) - -- Runtime Function: double __fractqqdf (short fract A) - -- Runtime Function: short fract __fracthqqq2 (fract A) - -- Runtime Function: long fract __fracthqsq2 (fract A) - -- Runtime Function: long long fract __fracthqdq2 (fract A) - -- Runtime Function: short accum __fracthqha (fract A) - -- Runtime Function: accum __fracthqsa (fract A) - -- Runtime Function: long accum __fracthqda (fract A) - -- Runtime Function: long long accum __fracthqta (fract A) - -- Runtime Function: unsigned short fract __fracthquqq (fract A) - -- Runtime Function: unsigned fract __fracthquhq (fract A) - -- Runtime Function: unsigned long fract __fracthqusq (fract A) - -- Runtime Function: unsigned long long fract __fracthqudq (fract A) - -- Runtime Function: unsigned short accum __fracthquha (fract A) - -- Runtime Function: unsigned accum __fracthqusa (fract A) - -- Runtime Function: unsigned long accum __fracthquda (fract A) - -- Runtime Function: unsigned long long accum __fracthquta (fract A) - -- Runtime Function: signed char __fracthqqi (fract A) - -- Runtime Function: short __fracthqhi (fract A) - -- Runtime Function: int __fracthqsi (fract A) - -- Runtime Function: long __fracthqdi (fract A) - -- Runtime Function: long long __fracthqti (fract A) - -- Runtime Function: float __fracthqsf (fract A) - -- Runtime Function: double __fracthqdf (fract A) - -- Runtime Function: short fract __fractsqqq2 (long fract A) - -- Runtime Function: fract __fractsqhq2 (long fract A) - -- Runtime Function: long long fract __fractsqdq2 (long fract A) - -- Runtime Function: short accum __fractsqha (long fract A) - -- Runtime Function: accum __fractsqsa (long fract A) - -- Runtime Function: long accum __fractsqda (long fract A) - -- Runtime Function: long long accum __fractsqta (long fract A) - -- Runtime Function: unsigned short fract __fractsquqq (long fract A) - -- Runtime Function: unsigned fract __fractsquhq (long fract A) - -- Runtime Function: unsigned long fract __fractsqusq (long fract A) - -- Runtime Function: unsigned long long fract __fractsqudq (long fract - A) - -- Runtime Function: unsigned short accum __fractsquha (long fract A) - -- Runtime Function: unsigned accum __fractsqusa (long fract A) - -- Runtime Function: unsigned long accum __fractsquda (long fract A) - -- Runtime Function: unsigned long long accum __fractsquta (long fract - A) - -- Runtime Function: signed char __fractsqqi (long fract A) - -- Runtime Function: short __fractsqhi (long fract A) - -- Runtime Function: int __fractsqsi (long fract A) - -- Runtime Function: long __fractsqdi (long fract A) - -- Runtime Function: long long __fractsqti (long fract A) - -- Runtime Function: float __fractsqsf (long fract A) - -- Runtime Function: double __fractsqdf (long fract A) - -- Runtime Function: short fract __fractdqqq2 (long long fract A) - -- Runtime Function: fract __fractdqhq2 (long long fract A) - -- Runtime Function: long fract __fractdqsq2 (long long fract A) - -- Runtime Function: short accum __fractdqha (long long fract A) - -- Runtime Function: accum __fractdqsa (long long fract A) - -- Runtime Function: long accum __fractdqda (long long fract A) - -- Runtime Function: long long accum __fractdqta (long long fract A) - -- Runtime Function: unsigned short fract __fractdquqq (long long fract - A) - -- Runtime Function: unsigned fract __fractdquhq (long long fract A) - -- Runtime Function: unsigned long fract __fractdqusq (long long fract - A) - -- Runtime Function: unsigned long long fract __fractdqudq (long long - fract A) - -- Runtime Function: unsigned short accum __fractdquha (long long fract - A) - -- Runtime Function: unsigned accum __fractdqusa (long long fract A) - -- Runtime Function: unsigned long accum __fractdquda (long long fract - A) - -- Runtime Function: unsigned long long accum __fractdquta (long long - fract A) - -- Runtime Function: signed char __fractdqqi (long long fract A) - -- Runtime Function: short __fractdqhi (long long fract A) - -- Runtime Function: int __fractdqsi (long long fract A) - -- Runtime Function: long __fractdqdi (long long fract A) - -- Runtime Function: long long __fractdqti (long long fract A) - -- Runtime Function: float __fractdqsf (long long fract A) - -- Runtime Function: double __fractdqdf (long long fract A) - -- Runtime Function: short fract __fracthaqq (short accum A) - -- Runtime Function: fract __fracthahq (short accum A) - -- Runtime Function: long fract __fracthasq (short accum A) - -- Runtime Function: long long fract __fracthadq (short accum A) - -- Runtime Function: accum __fracthasa2 (short accum A) - -- Runtime Function: long accum __fracthada2 (short accum A) - -- Runtime Function: long long accum __fracthata2 (short accum A) - -- Runtime Function: unsigned short fract __fracthauqq (short accum A) - -- Runtime Function: unsigned fract __fracthauhq (short accum A) - -- Runtime Function: unsigned long fract __fracthausq (short accum A) - -- Runtime Function: unsigned long long fract __fracthaudq (short accum - A) - -- Runtime Function: unsigned short accum __fracthauha (short accum A) - -- Runtime Function: unsigned accum __fracthausa (short accum A) - -- Runtime Function: unsigned long accum __fracthauda (short accum A) - -- Runtime Function: unsigned long long accum __fracthauta (short accum - A) - -- Runtime Function: signed char __fracthaqi (short accum A) - -- Runtime Function: short __fracthahi (short accum A) - -- Runtime Function: int __fracthasi (short accum A) - -- Runtime Function: long __fracthadi (short accum A) - -- Runtime Function: long long __fracthati (short accum A) - -- Runtime Function: float __fracthasf (short accum A) - -- Runtime Function: double __fracthadf (short accum A) - -- Runtime Function: short fract __fractsaqq (accum A) - -- Runtime Function: fract __fractsahq (accum A) - -- Runtime Function: long fract __fractsasq (accum A) - -- Runtime Function: long long fract __fractsadq (accum A) - -- Runtime Function: short accum __fractsaha2 (accum A) - -- Runtime Function: long accum __fractsada2 (accum A) - -- Runtime Function: long long accum __fractsata2 (accum A) - -- Runtime Function: unsigned short fract __fractsauqq (accum A) - -- Runtime Function: unsigned fract __fractsauhq (accum A) - -- Runtime Function: unsigned long fract __fractsausq (accum A) - -- Runtime Function: unsigned long long fract __fractsaudq (accum A) - -- Runtime Function: unsigned short accum __fractsauha (accum A) - -- Runtime Function: unsigned accum __fractsausa (accum A) - -- Runtime Function: unsigned long accum __fractsauda (accum A) - -- Runtime Function: unsigned long long accum __fractsauta (accum A) - -- Runtime Function: signed char __fractsaqi (accum A) - -- Runtime Function: short __fractsahi (accum A) - -- Runtime Function: int __fractsasi (accum A) - -- Runtime Function: long __fractsadi (accum A) - -- Runtime Function: long long __fractsati (accum A) - -- Runtime Function: float __fractsasf (accum A) - -- Runtime Function: double __fractsadf (accum A) - -- Runtime Function: short fract __fractdaqq (long accum A) - -- Runtime Function: fract __fractdahq (long accum A) - -- Runtime Function: long fract __fractdasq (long accum A) - -- Runtime Function: long long fract __fractdadq (long accum A) - -- Runtime Function: short accum __fractdaha2 (long accum A) - -- Runtime Function: accum __fractdasa2 (long accum A) - -- Runtime Function: long long accum __fractdata2 (long accum A) - -- Runtime Function: unsigned short fract __fractdauqq (long accum A) - -- Runtime Function: unsigned fract __fractdauhq (long accum A) - -- Runtime Function: unsigned long fract __fractdausq (long accum A) - -- Runtime Function: unsigned long long fract __fractdaudq (long accum - A) - -- Runtime Function: unsigned short accum __fractdauha (long accum A) - -- Runtime Function: unsigned accum __fractdausa (long accum A) - -- Runtime Function: unsigned long accum __fractdauda (long accum A) - -- Runtime Function: unsigned long long accum __fractdauta (long accum - A) - -- Runtime Function: signed char __fractdaqi (long accum A) - -- Runtime Function: short __fractdahi (long accum A) - -- Runtime Function: int __fractdasi (long accum A) - -- Runtime Function: long __fractdadi (long accum A) - -- Runtime Function: long long __fractdati (long accum A) - -- Runtime Function: float __fractdasf (long accum A) - -- Runtime Function: double __fractdadf (long accum A) - -- Runtime Function: short fract __fracttaqq (long long accum A) - -- Runtime Function: fract __fracttahq (long long accum A) - -- Runtime Function: long fract __fracttasq (long long accum A) - -- Runtime Function: long long fract __fracttadq (long long accum A) - -- Runtime Function: short accum __fracttaha2 (long long accum A) - -- Runtime Function: accum __fracttasa2 (long long accum A) - -- Runtime Function: long accum __fracttada2 (long long accum A) - -- Runtime Function: unsigned short fract __fracttauqq (long long accum - A) - -- Runtime Function: unsigned fract __fracttauhq (long long accum A) - -- Runtime Function: unsigned long fract __fracttausq (long long accum - A) - -- Runtime Function: unsigned long long fract __fracttaudq (long long - accum A) - -- Runtime Function: unsigned short accum __fracttauha (long long accum - A) - -- Runtime Function: unsigned accum __fracttausa (long long accum A) - -- Runtime Function: unsigned long accum __fracttauda (long long accum - A) - -- Runtime Function: unsigned long long accum __fracttauta (long long - accum A) - -- Runtime Function: signed char __fracttaqi (long long accum A) - -- Runtime Function: short __fracttahi (long long accum A) - -- Runtime Function: int __fracttasi (long long accum A) - -- Runtime Function: long __fracttadi (long long accum A) - -- Runtime Function: long long __fracttati (long long accum A) - -- Runtime Function: float __fracttasf (long long accum A) - -- Runtime Function: double __fracttadf (long long accum A) - -- Runtime Function: short fract __fractuqqqq (unsigned short fract A) - -- Runtime Function: fract __fractuqqhq (unsigned short fract A) - -- Runtime Function: long fract __fractuqqsq (unsigned short fract A) - -- Runtime Function: long long fract __fractuqqdq (unsigned short fract - A) - -- Runtime Function: short accum __fractuqqha (unsigned short fract A) - -- Runtime Function: accum __fractuqqsa (unsigned short fract A) - -- Runtime Function: long accum __fractuqqda (unsigned short fract A) - -- Runtime Function: long long accum __fractuqqta (unsigned short fract - A) - -- Runtime Function: unsigned fract __fractuqquhq2 (unsigned short - fract A) - -- Runtime Function: unsigned long fract __fractuqqusq2 (unsigned short - fract A) - -- Runtime Function: unsigned long long fract __fractuqqudq2 (unsigned - short fract A) - -- Runtime Function: unsigned short accum __fractuqquha (unsigned short - fract A) - -- Runtime Function: unsigned accum __fractuqqusa (unsigned short fract - A) - -- Runtime Function: unsigned long accum __fractuqquda (unsigned short - fract A) - -- Runtime Function: unsigned long long accum __fractuqquta (unsigned - short fract A) - -- Runtime Function: signed char __fractuqqqi (unsigned short fract A) - -- Runtime Function: short __fractuqqhi (unsigned short fract A) - -- Runtime Function: int __fractuqqsi (unsigned short fract A) - -- Runtime Function: long __fractuqqdi (unsigned short fract A) - -- Runtime Function: long long __fractuqqti (unsigned short fract A) - -- Runtime Function: float __fractuqqsf (unsigned short fract A) - -- Runtime Function: double __fractuqqdf (unsigned short fract A) - -- Runtime Function: short fract __fractuhqqq (unsigned fract A) - -- Runtime Function: fract __fractuhqhq (unsigned fract A) - -- Runtime Function: long fract __fractuhqsq (unsigned fract A) - -- Runtime Function: long long fract __fractuhqdq (unsigned fract A) - -- Runtime Function: short accum __fractuhqha (unsigned fract A) - -- Runtime Function: accum __fractuhqsa (unsigned fract A) - -- Runtime Function: long accum __fractuhqda (unsigned fract A) - -- Runtime Function: long long accum __fractuhqta (unsigned fract A) - -- Runtime Function: unsigned short fract __fractuhquqq2 (unsigned - fract A) - -- Runtime Function: unsigned long fract __fractuhqusq2 (unsigned fract - A) - -- Runtime Function: unsigned long long fract __fractuhqudq2 (unsigned - fract A) - -- Runtime Function: unsigned short accum __fractuhquha (unsigned fract - A) - -- Runtime Function: unsigned accum __fractuhqusa (unsigned fract A) - -- Runtime Function: unsigned long accum __fractuhquda (unsigned fract - A) - -- Runtime Function: unsigned long long accum __fractuhquta (unsigned - fract A) - -- Runtime Function: signed char __fractuhqqi (unsigned fract A) - -- Runtime Function: short __fractuhqhi (unsigned fract A) - -- Runtime Function: int __fractuhqsi (unsigned fract A) - -- Runtime Function: long __fractuhqdi (unsigned fract A) - -- Runtime Function: long long __fractuhqti (unsigned fract A) - -- Runtime Function: float __fractuhqsf (unsigned fract A) - -- Runtime Function: double __fractuhqdf (unsigned fract A) - -- Runtime Function: short fract __fractusqqq (unsigned long fract A) - -- Runtime Function: fract __fractusqhq (unsigned long fract A) - -- Runtime Function: long fract __fractusqsq (unsigned long fract A) - -- Runtime Function: long long fract __fractusqdq (unsigned long fract - A) - -- Runtime Function: short accum __fractusqha (unsigned long fract A) - -- Runtime Function: accum __fractusqsa (unsigned long fract A) - -- Runtime Function: long accum __fractusqda (unsigned long fract A) - -- Runtime Function: long long accum __fractusqta (unsigned long fract - A) - -- Runtime Function: unsigned short fract __fractusquqq2 (unsigned long - fract A) - -- Runtime Function: unsigned fract __fractusquhq2 (unsigned long fract - A) - -- Runtime Function: unsigned long long fract __fractusqudq2 (unsigned - long fract A) - -- Runtime Function: unsigned short accum __fractusquha (unsigned long - fract A) - -- Runtime Function: unsigned accum __fractusqusa (unsigned long fract - A) - -- Runtime Function: unsigned long accum __fractusquda (unsigned long - fract A) - -- Runtime Function: unsigned long long accum __fractusquta (unsigned - long fract A) - -- Runtime Function: signed char __fractusqqi (unsigned long fract A) - -- Runtime Function: short __fractusqhi (unsigned long fract A) - -- Runtime Function: int __fractusqsi (unsigned long fract A) - -- Runtime Function: long __fractusqdi (unsigned long fract A) - -- Runtime Function: long long __fractusqti (unsigned long fract A) - -- Runtime Function: float __fractusqsf (unsigned long fract A) - -- Runtime Function: double __fractusqdf (unsigned long fract A) - -- Runtime Function: short fract __fractudqqq (unsigned long long fract - A) - -- Runtime Function: fract __fractudqhq (unsigned long long fract A) - -- Runtime Function: long fract __fractudqsq (unsigned long long fract - A) - -- Runtime Function: long long fract __fractudqdq (unsigned long long - fract A) - -- Runtime Function: short accum __fractudqha (unsigned long long fract - A) - -- Runtime Function: accum __fractudqsa (unsigned long long fract A) - -- Runtime Function: long accum __fractudqda (unsigned long long fract - A) - -- Runtime Function: long long accum __fractudqta (unsigned long long - fract A) - -- Runtime Function: unsigned short fract __fractudquqq2 (unsigned long - long fract A) - -- Runtime Function: unsigned fract __fractudquhq2 (unsigned long long - fract A) - -- Runtime Function: unsigned long fract __fractudqusq2 (unsigned long - long fract A) - -- Runtime Function: unsigned short accum __fractudquha (unsigned long - long fract A) - -- Runtime Function: unsigned accum __fractudqusa (unsigned long long - fract A) - -- Runtime Function: unsigned long accum __fractudquda (unsigned long - long fract A) - -- Runtime Function: unsigned long long accum __fractudquta (unsigned - long long fract A) - -- Runtime Function: signed char __fractudqqi (unsigned long long fract - A) - -- Runtime Function: short __fractudqhi (unsigned long long fract A) - -- Runtime Function: int __fractudqsi (unsigned long long fract A) - -- Runtime Function: long __fractudqdi (unsigned long long fract A) - -- Runtime Function: long long __fractudqti (unsigned long long fract - A) - -- Runtime Function: float __fractudqsf (unsigned long long fract A) - -- Runtime Function: double __fractudqdf (unsigned long long fract A) - -- Runtime Function: short fract __fractuhaqq (unsigned short accum A) - -- Runtime Function: fract __fractuhahq (unsigned short accum A) - -- Runtime Function: long fract __fractuhasq (unsigned short accum A) - -- Runtime Function: long long fract __fractuhadq (unsigned short accum - A) - -- Runtime Function: short accum __fractuhaha (unsigned short accum A) - -- Runtime Function: accum __fractuhasa (unsigned short accum A) - -- Runtime Function: long accum __fractuhada (unsigned short accum A) - -- Runtime Function: long long accum __fractuhata (unsigned short accum - A) - -- Runtime Function: unsigned short fract __fractuhauqq (unsigned short - accum A) - -- Runtime Function: unsigned fract __fractuhauhq (unsigned short accum - A) - -- Runtime Function: unsigned long fract __fractuhausq (unsigned short - accum A) - -- Runtime Function: unsigned long long fract __fractuhaudq (unsigned - short accum A) - -- Runtime Function: unsigned accum __fractuhausa2 (unsigned short - accum A) - -- Runtime Function: unsigned long accum __fractuhauda2 (unsigned short - accum A) - -- Runtime Function: unsigned long long accum __fractuhauta2 (unsigned - short accum A) - -- Runtime Function: signed char __fractuhaqi (unsigned short accum A) - -- Runtime Function: short __fractuhahi (unsigned short accum A) - -- Runtime Function: int __fractuhasi (unsigned short accum A) - -- Runtime Function: long __fractuhadi (unsigned short accum A) - -- Runtime Function: long long __fractuhati (unsigned short accum A) - -- Runtime Function: float __fractuhasf (unsigned short accum A) - -- Runtime Function: double __fractuhadf (unsigned short accum A) - -- Runtime Function: short fract __fractusaqq (unsigned accum A) - -- Runtime Function: fract __fractusahq (unsigned accum A) - -- Runtime Function: long fract __fractusasq (unsigned accum A) - -- Runtime Function: long long fract __fractusadq (unsigned accum A) - -- Runtime Function: short accum __fractusaha (unsigned accum A) - -- Runtime Function: accum __fractusasa (unsigned accum A) - -- Runtime Function: long accum __fractusada (unsigned accum A) - -- Runtime Function: long long accum __fractusata (unsigned accum A) - -- Runtime Function: unsigned short fract __fractusauqq (unsigned accum - A) - -- Runtime Function: unsigned fract __fractusauhq (unsigned accum A) - -- Runtime Function: unsigned long fract __fractusausq (unsigned accum - A) - -- Runtime Function: unsigned long long fract __fractusaudq (unsigned - accum A) - -- Runtime Function: unsigned short accum __fractusauha2 (unsigned - accum A) - -- Runtime Function: unsigned long accum __fractusauda2 (unsigned accum - A) - -- Runtime Function: unsigned long long accum __fractusauta2 (unsigned - accum A) - -- Runtime Function: signed char __fractusaqi (unsigned accum A) - -- Runtime Function: short __fractusahi (unsigned accum A) - -- Runtime Function: int __fractusasi (unsigned accum A) - -- Runtime Function: long __fractusadi (unsigned accum A) - -- Runtime Function: long long __fractusati (unsigned accum A) - -- Runtime Function: float __fractusasf (unsigned accum A) - -- Runtime Function: double __fractusadf (unsigned accum A) - -- Runtime Function: short fract __fractudaqq (unsigned long accum A) - -- Runtime Function: fract __fractudahq (unsigned long accum A) - -- Runtime Function: long fract __fractudasq (unsigned long accum A) - -- Runtime Function: long long fract __fractudadq (unsigned long accum - A) - -- Runtime Function: short accum __fractudaha (unsigned long accum A) - -- Runtime Function: accum __fractudasa (unsigned long accum A) - -- Runtime Function: long accum __fractudada (unsigned long accum A) - -- Runtime Function: long long accum __fractudata (unsigned long accum - A) - -- Runtime Function: unsigned short fract __fractudauqq (unsigned long - accum A) - -- Runtime Function: unsigned fract __fractudauhq (unsigned long accum - A) - -- Runtime Function: unsigned long fract __fractudausq (unsigned long - accum A) - -- Runtime Function: unsigned long long fract __fractudaudq (unsigned - long accum A) - -- Runtime Function: unsigned short accum __fractudauha2 (unsigned long - accum A) - -- Runtime Function: unsigned accum __fractudausa2 (unsigned long accum - A) - -- Runtime Function: unsigned long long accum __fractudauta2 (unsigned - long accum A) - -- Runtime Function: signed char __fractudaqi (unsigned long accum A) - -- Runtime Function: short __fractudahi (unsigned long accum A) - -- Runtime Function: int __fractudasi (unsigned long accum A) - -- Runtime Function: long __fractudadi (unsigned long accum A) - -- Runtime Function: long long __fractudati (unsigned long accum A) - -- Runtime Function: float __fractudasf (unsigned long accum A) - -- Runtime Function: double __fractudadf (unsigned long accum A) - -- Runtime Function: short fract __fractutaqq (unsigned long long accum - A) - -- Runtime Function: fract __fractutahq (unsigned long long accum A) - -- Runtime Function: long fract __fractutasq (unsigned long long accum - A) - -- Runtime Function: long long fract __fractutadq (unsigned long long - accum A) - -- Runtime Function: short accum __fractutaha (unsigned long long accum - A) - -- Runtime Function: accum __fractutasa (unsigned long long accum A) - -- Runtime Function: long accum __fractutada (unsigned long long accum - A) - -- Runtime Function: long long accum __fractutata (unsigned long long - accum A) - -- Runtime Function: unsigned short fract __fractutauqq (unsigned long - long accum A) - -- Runtime Function: unsigned fract __fractutauhq (unsigned long long - accum A) - -- Runtime Function: unsigned long fract __fractutausq (unsigned long - long accum A) - -- Runtime Function: unsigned long long fract __fractutaudq (unsigned - long long accum A) - -- Runtime Function: unsigned short accum __fractutauha2 (unsigned long - long accum A) - -- Runtime Function: unsigned accum __fractutausa2 (unsigned long long - accum A) - -- Runtime Function: unsigned long accum __fractutauda2 (unsigned long - long accum A) - -- Runtime Function: signed char __fractutaqi (unsigned long long accum - A) - -- Runtime Function: short __fractutahi (unsigned long long accum A) - -- Runtime Function: int __fractutasi (unsigned long long accum A) - -- Runtime Function: long __fractutadi (unsigned long long accum A) - -- Runtime Function: long long __fractutati (unsigned long long accum - A) - -- Runtime Function: float __fractutasf (unsigned long long accum A) - -- Runtime Function: double __fractutadf (unsigned long long accum A) - -- Runtime Function: short fract __fractqiqq (signed char A) - -- Runtime Function: fract __fractqihq (signed char A) - -- Runtime Function: long fract __fractqisq (signed char A) - -- Runtime Function: long long fract __fractqidq (signed char A) - -- Runtime Function: short accum __fractqiha (signed char A) - -- Runtime Function: accum __fractqisa (signed char A) - -- Runtime Function: long accum __fractqida (signed char A) - -- Runtime Function: long long accum __fractqita (signed char A) - -- Runtime Function: unsigned short fract __fractqiuqq (signed char A) - -- Runtime Function: unsigned fract __fractqiuhq (signed char A) - -- Runtime Function: unsigned long fract __fractqiusq (signed char A) - -- Runtime Function: unsigned long long fract __fractqiudq (signed char - A) - -- Runtime Function: unsigned short accum __fractqiuha (signed char A) - -- Runtime Function: unsigned accum __fractqiusa (signed char A) - -- Runtime Function: unsigned long accum __fractqiuda (signed char A) - -- Runtime Function: unsigned long long accum __fractqiuta (signed char - A) - -- Runtime Function: short fract __fracthiqq (short A) - -- Runtime Function: fract __fracthihq (short A) - -- Runtime Function: long fract __fracthisq (short A) - -- Runtime Function: long long fract __fracthidq (short A) - -- Runtime Function: short accum __fracthiha (short A) - -- Runtime Function: accum __fracthisa (short A) - -- Runtime Function: long accum __fracthida (short A) - -- Runtime Function: long long accum __fracthita (short A) - -- Runtime Function: unsigned short fract __fracthiuqq (short A) - -- Runtime Function: unsigned fract __fracthiuhq (short A) - -- Runtime Function: unsigned long fract __fracthiusq (short A) - -- Runtime Function: unsigned long long fract __fracthiudq (short A) - -- Runtime Function: unsigned short accum __fracthiuha (short A) - -- Runtime Function: unsigned accum __fracthiusa (short A) - -- Runtime Function: unsigned long accum __fracthiuda (short A) - -- Runtime Function: unsigned long long accum __fracthiuta (short A) - -- Runtime Function: short fract __fractsiqq (int A) - -- Runtime Function: fract __fractsihq (int A) - -- Runtime Function: long fract __fractsisq (int A) - -- Runtime Function: long long fract __fractsidq (int A) - -- Runtime Function: short accum __fractsiha (int A) - -- Runtime Function: accum __fractsisa (int A) - -- Runtime Function: long accum __fractsida (int A) - -- Runtime Function: long long accum __fractsita (int A) - -- Runtime Function: unsigned short fract __fractsiuqq (int A) - -- Runtime Function: unsigned fract __fractsiuhq (int A) - -- Runtime Function: unsigned long fract __fractsiusq (int A) - -- Runtime Function: unsigned long long fract __fractsiudq (int A) - -- Runtime Function: unsigned short accum __fractsiuha (int A) - -- Runtime Function: unsigned accum __fractsiusa (int A) - -- Runtime Function: unsigned long accum __fractsiuda (int A) - -- Runtime Function: unsigned long long accum __fractsiuta (int A) - -- Runtime Function: short fract __fractdiqq (long A) - -- Runtime Function: fract __fractdihq (long A) - -- Runtime Function: long fract __fractdisq (long A) - -- Runtime Function: long long fract __fractdidq (long A) - -- Runtime Function: short accum __fractdiha (long A) - -- Runtime Function: accum __fractdisa (long A) - -- Runtime Function: long accum __fractdida (long A) - -- Runtime Function: long long accum __fractdita (long A) - -- Runtime Function: unsigned short fract __fractdiuqq (long A) - -- Runtime Function: unsigned fract __fractdiuhq (long A) - -- Runtime Function: unsigned long fract __fractdiusq (long A) - -- Runtime Function: unsigned long long fract __fractdiudq (long A) - -- Runtime Function: unsigned short accum __fractdiuha (long A) - -- Runtime Function: unsigned accum __fractdiusa (long A) - -- Runtime Function: unsigned long accum __fractdiuda (long A) - -- Runtime Function: unsigned long long accum __fractdiuta (long A) - -- Runtime Function: short fract __fracttiqq (long long A) - -- Runtime Function: fract __fracttihq (long long A) - -- Runtime Function: long fract __fracttisq (long long A) - -- Runtime Function: long long fract __fracttidq (long long A) - -- Runtime Function: short accum __fracttiha (long long A) - -- Runtime Function: accum __fracttisa (long long A) - -- Runtime Function: long accum __fracttida (long long A) - -- Runtime Function: long long accum __fracttita (long long A) - -- Runtime Function: unsigned short fract __fracttiuqq (long long A) - -- Runtime Function: unsigned fract __fracttiuhq (long long A) - -- Runtime Function: unsigned long fract __fracttiusq (long long A) - -- Runtime Function: unsigned long long fract __fracttiudq (long long - A) - -- Runtime Function: unsigned short accum __fracttiuha (long long A) - -- Runtime Function: unsigned accum __fracttiusa (long long A) - -- Runtime Function: unsigned long accum __fracttiuda (long long A) - -- Runtime Function: unsigned long long accum __fracttiuta (long long - A) - -- Runtime Function: short fract __fractsfqq (float A) - -- Runtime Function: fract __fractsfhq (float A) - -- Runtime Function: long fract __fractsfsq (float A) - -- Runtime Function: long long fract __fractsfdq (float A) - -- Runtime Function: short accum __fractsfha (float A) - -- Runtime Function: accum __fractsfsa (float A) - -- Runtime Function: long accum __fractsfda (float A) - -- Runtime Function: long long accum __fractsfta (float A) - -- Runtime Function: unsigned short fract __fractsfuqq (float A) - -- Runtime Function: unsigned fract __fractsfuhq (float A) - -- Runtime Function: unsigned long fract __fractsfusq (float A) - -- Runtime Function: unsigned long long fract __fractsfudq (float A) - -- Runtime Function: unsigned short accum __fractsfuha (float A) - -- Runtime Function: unsigned accum __fractsfusa (float A) - -- Runtime Function: unsigned long accum __fractsfuda (float A) - -- Runtime Function: unsigned long long accum __fractsfuta (float A) - -- Runtime Function: short fract __fractdfqq (double A) - -- Runtime Function: fract __fractdfhq (double A) - -- Runtime Function: long fract __fractdfsq (double A) - -- Runtime Function: long long fract __fractdfdq (double A) - -- Runtime Function: short accum __fractdfha (double A) - -- Runtime Function: accum __fractdfsa (double A) - -- Runtime Function: long accum __fractdfda (double A) - -- Runtime Function: long long accum __fractdfta (double A) - -- Runtime Function: unsigned short fract __fractdfuqq (double A) - -- Runtime Function: unsigned fract __fractdfuhq (double A) - -- Runtime Function: unsigned long fract __fractdfusq (double A) - -- Runtime Function: unsigned long long fract __fractdfudq (double A) - -- Runtime Function: unsigned short accum __fractdfuha (double A) - -- Runtime Function: unsigned accum __fractdfusa (double A) - -- Runtime Function: unsigned long accum __fractdfuda (double A) - -- Runtime Function: unsigned long long accum __fractdfuta (double A) - These functions convert from fractional and signed non-fractionals - to fractionals and signed non-fractionals, without saturation. - - -- Runtime Function: fract __satfractqqhq2 (short fract A) - -- Runtime Function: long fract __satfractqqsq2 (short fract A) - -- Runtime Function: long long fract __satfractqqdq2 (short fract A) - -- Runtime Function: short accum __satfractqqha (short fract A) - -- Runtime Function: accum __satfractqqsa (short fract A) - -- Runtime Function: long accum __satfractqqda (short fract A) - -- Runtime Function: long long accum __satfractqqta (short fract A) - -- Runtime Function: unsigned short fract __satfractqquqq (short fract - A) - -- Runtime Function: unsigned fract __satfractqquhq (short fract A) - -- Runtime Function: unsigned long fract __satfractqqusq (short fract - A) - -- Runtime Function: unsigned long long fract __satfractqqudq (short - fract A) - -- Runtime Function: unsigned short accum __satfractqquha (short fract - A) - -- Runtime Function: unsigned accum __satfractqqusa (short fract A) - -- Runtime Function: unsigned long accum __satfractqquda (short fract - A) - -- Runtime Function: unsigned long long accum __satfractqquta (short - fract A) - -- Runtime Function: short fract __satfracthqqq2 (fract A) - -- Runtime Function: long fract __satfracthqsq2 (fract A) - -- Runtime Function: long long fract __satfracthqdq2 (fract A) - -- Runtime Function: short accum __satfracthqha (fract A) - -- Runtime Function: accum __satfracthqsa (fract A) - -- Runtime Function: long accum __satfracthqda (fract A) - -- Runtime Function: long long accum __satfracthqta (fract A) - -- Runtime Function: unsigned short fract __satfracthquqq (fract A) - -- Runtime Function: unsigned fract __satfracthquhq (fract A) - -- Runtime Function: unsigned long fract __satfracthqusq (fract A) - -- Runtime Function: unsigned long long fract __satfracthqudq (fract A) - -- Runtime Function: unsigned short accum __satfracthquha (fract A) - -- Runtime Function: unsigned accum __satfracthqusa (fract A) - -- Runtime Function: unsigned long accum __satfracthquda (fract A) - -- Runtime Function: unsigned long long accum __satfracthquta (fract A) - -- Runtime Function: short fract __satfractsqqq2 (long fract A) - -- Runtime Function: fract __satfractsqhq2 (long fract A) - -- Runtime Function: long long fract __satfractsqdq2 (long fract A) - -- Runtime Function: short accum __satfractsqha (long fract A) - -- Runtime Function: accum __satfractsqsa (long fract A) - -- Runtime Function: long accum __satfractsqda (long fract A) - -- Runtime Function: long long accum __satfractsqta (long fract A) - -- Runtime Function: unsigned short fract __satfractsquqq (long fract - A) - -- Runtime Function: unsigned fract __satfractsquhq (long fract A) - -- Runtime Function: unsigned long fract __satfractsqusq (long fract A) - -- Runtime Function: unsigned long long fract __satfractsqudq (long - fract A) - -- Runtime Function: unsigned short accum __satfractsquha (long fract - A) - -- Runtime Function: unsigned accum __satfractsqusa (long fract A) - -- Runtime Function: unsigned long accum __satfractsquda (long fract A) - -- Runtime Function: unsigned long long accum __satfractsquta (long - fract A) - -- Runtime Function: short fract __satfractdqqq2 (long long fract A) - -- Runtime Function: fract __satfractdqhq2 (long long fract A) - -- Runtime Function: long fract __satfractdqsq2 (long long fract A) - -- Runtime Function: short accum __satfractdqha (long long fract A) - -- Runtime Function: accum __satfractdqsa (long long fract A) - -- Runtime Function: long accum __satfractdqda (long long fract A) - -- Runtime Function: long long accum __satfractdqta (long long fract A) - -- Runtime Function: unsigned short fract __satfractdquqq (long long - fract A) - -- Runtime Function: unsigned fract __satfractdquhq (long long fract A) - -- Runtime Function: unsigned long fract __satfractdqusq (long long - fract A) - -- Runtime Function: unsigned long long fract __satfractdqudq (long - long fract A) - -- Runtime Function: unsigned short accum __satfractdquha (long long - fract A) - -- Runtime Function: unsigned accum __satfractdqusa (long long fract A) - -- Runtime Function: unsigned long accum __satfractdquda (long long - fract A) - -- Runtime Function: unsigned long long accum __satfractdquta (long - long fract A) - -- Runtime Function: short fract __satfracthaqq (short accum A) - -- Runtime Function: fract __satfracthahq (short accum A) - -- Runtime Function: long fract __satfracthasq (short accum A) - -- Runtime Function: long long fract __satfracthadq (short accum A) - -- Runtime Function: accum __satfracthasa2 (short accum A) - -- Runtime Function: long accum __satfracthada2 (short accum A) - -- Runtime Function: long long accum __satfracthata2 (short accum A) - -- Runtime Function: unsigned short fract __satfracthauqq (short accum - A) - -- Runtime Function: unsigned fract __satfracthauhq (short accum A) - -- Runtime Function: unsigned long fract __satfracthausq (short accum - A) - -- Runtime Function: unsigned long long fract __satfracthaudq (short - accum A) - -- Runtime Function: unsigned short accum __satfracthauha (short accum - A) - -- Runtime Function: unsigned accum __satfracthausa (short accum A) - -- Runtime Function: unsigned long accum __satfracthauda (short accum - A) - -- Runtime Function: unsigned long long accum __satfracthauta (short - accum A) - -- Runtime Function: short fract __satfractsaqq (accum A) - -- Runtime Function: fract __satfractsahq (accum A) - -- Runtime Function: long fract __satfractsasq (accum A) - -- Runtime Function: long long fract __satfractsadq (accum A) - -- Runtime Function: short accum __satfractsaha2 (accum A) - -- Runtime Function: long accum __satfractsada2 (accum A) - -- Runtime Function: long long accum __satfractsata2 (accum A) - -- Runtime Function: unsigned short fract __satfractsauqq (accum A) - -- Runtime Function: unsigned fract __satfractsauhq (accum A) - -- Runtime Function: unsigned long fract __satfractsausq (accum A) - -- Runtime Function: unsigned long long fract __satfractsaudq (accum A) - -- Runtime Function: unsigned short accum __satfractsauha (accum A) - -- Runtime Function: unsigned accum __satfractsausa (accum A) - -- Runtime Function: unsigned long accum __satfractsauda (accum A) - -- Runtime Function: unsigned long long accum __satfractsauta (accum A) - -- Runtime Function: short fract __satfractdaqq (long accum A) - -- Runtime Function: fract __satfractdahq (long accum A) - -- Runtime Function: long fract __satfractdasq (long accum A) - -- Runtime Function: long long fract __satfractdadq (long accum A) - -- Runtime Function: short accum __satfractdaha2 (long accum A) - -- Runtime Function: accum __satfractdasa2 (long accum A) - -- Runtime Function: long long accum __satfractdata2 (long accum A) - -- Runtime Function: unsigned short fract __satfractdauqq (long accum - A) - -- Runtime Function: unsigned fract __satfractdauhq (long accum A) - -- Runtime Function: unsigned long fract __satfractdausq (long accum A) - -- Runtime Function: unsigned long long fract __satfractdaudq (long - accum A) - -- Runtime Function: unsigned short accum __satfractdauha (long accum - A) - -- Runtime Function: unsigned accum __satfractdausa (long accum A) - -- Runtime Function: unsigned long accum __satfractdauda (long accum A) - -- Runtime Function: unsigned long long accum __satfractdauta (long - accum A) - -- Runtime Function: short fract __satfracttaqq (long long accum A) - -- Runtime Function: fract __satfracttahq (long long accum A) - -- Runtime Function: long fract __satfracttasq (long long accum A) - -- Runtime Function: long long fract __satfracttadq (long long accum A) - -- Runtime Function: short accum __satfracttaha2 (long long accum A) - -- Runtime Function: accum __satfracttasa2 (long long accum A) - -- Runtime Function: long accum __satfracttada2 (long long accum A) - -- Runtime Function: unsigned short fract __satfracttauqq (long long - accum A) - -- Runtime Function: unsigned fract __satfracttauhq (long long accum A) - -- Runtime Function: unsigned long fract __satfracttausq (long long - accum A) - -- Runtime Function: unsigned long long fract __satfracttaudq (long - long accum A) - -- Runtime Function: unsigned short accum __satfracttauha (long long - accum A) - -- Runtime Function: unsigned accum __satfracttausa (long long accum A) - -- Runtime Function: unsigned long accum __satfracttauda (long long - accum A) - -- Runtime Function: unsigned long long accum __satfracttauta (long - long accum A) - -- Runtime Function: short fract __satfractuqqqq (unsigned short fract - A) - -- Runtime Function: fract __satfractuqqhq (unsigned short fract A) - -- Runtime Function: long fract __satfractuqqsq (unsigned short fract - A) - -- Runtime Function: long long fract __satfractuqqdq (unsigned short - fract A) - -- Runtime Function: short accum __satfractuqqha (unsigned short fract - A) - -- Runtime Function: accum __satfractuqqsa (unsigned short fract A) - -- Runtime Function: long accum __satfractuqqda (unsigned short fract - A) - -- Runtime Function: long long accum __satfractuqqta (unsigned short - fract A) - -- Runtime Function: unsigned fract __satfractuqquhq2 (unsigned short - fract A) - -- Runtime Function: unsigned long fract __satfractuqqusq2 (unsigned - short fract A) - -- Runtime Function: unsigned long long fract __satfractuqqudq2 - (unsigned short fract A) - -- Runtime Function: unsigned short accum __satfractuqquha (unsigned - short fract A) - -- Runtime Function: unsigned accum __satfractuqqusa (unsigned short - fract A) - -- Runtime Function: unsigned long accum __satfractuqquda (unsigned - short fract A) - -- Runtime Function: unsigned long long accum __satfractuqquta - (unsigned short fract A) - -- Runtime Function: short fract __satfractuhqqq (unsigned fract A) - -- Runtime Function: fract __satfractuhqhq (unsigned fract A) - -- Runtime Function: long fract __satfractuhqsq (unsigned fract A) - -- Runtime Function: long long fract __satfractuhqdq (unsigned fract A) - -- Runtime Function: short accum __satfractuhqha (unsigned fract A) - -- Runtime Function: accum __satfractuhqsa (unsigned fract A) - -- Runtime Function: long accum __satfractuhqda (unsigned fract A) - -- Runtime Function: long long accum __satfractuhqta (unsigned fract A) - -- Runtime Function: unsigned short fract __satfractuhquqq2 (unsigned - fract A) - -- Runtime Function: unsigned long fract __satfractuhqusq2 (unsigned - fract A) - -- Runtime Function: unsigned long long fract __satfractuhqudq2 - (unsigned fract A) - -- Runtime Function: unsigned short accum __satfractuhquha (unsigned - fract A) - -- Runtime Function: unsigned accum __satfractuhqusa (unsigned fract A) - -- Runtime Function: unsigned long accum __satfractuhquda (unsigned - fract A) - -- Runtime Function: unsigned long long accum __satfractuhquta - (unsigned fract A) - -- Runtime Function: short fract __satfractusqqq (unsigned long fract - A) - -- Runtime Function: fract __satfractusqhq (unsigned long fract A) - -- Runtime Function: long fract __satfractusqsq (unsigned long fract A) - -- Runtime Function: long long fract __satfractusqdq (unsigned long - fract A) - -- Runtime Function: short accum __satfractusqha (unsigned long fract - A) - -- Runtime Function: accum __satfractusqsa (unsigned long fract A) - -- Runtime Function: long accum __satfractusqda (unsigned long fract A) - -- Runtime Function: long long accum __satfractusqta (unsigned long - fract A) - -- Runtime Function: unsigned short fract __satfractusquqq2 (unsigned - long fract A) - -- Runtime Function: unsigned fract __satfractusquhq2 (unsigned long - fract A) - -- Runtime Function: unsigned long long fract __satfractusqudq2 - (unsigned long fract A) - -- Runtime Function: unsigned short accum __satfractusquha (unsigned - long fract A) - -- Runtime Function: unsigned accum __satfractusqusa (unsigned long - fract A) - -- Runtime Function: unsigned long accum __satfractusquda (unsigned - long fract A) - -- Runtime Function: unsigned long long accum __satfractusquta - (unsigned long fract A) - -- Runtime Function: short fract __satfractudqqq (unsigned long long - fract A) - -- Runtime Function: fract __satfractudqhq (unsigned long long fract A) - -- Runtime Function: long fract __satfractudqsq (unsigned long long - fract A) - -- Runtime Function: long long fract __satfractudqdq (unsigned long - long fract A) - -- Runtime Function: short accum __satfractudqha (unsigned long long - fract A) - -- Runtime Function: accum __satfractudqsa (unsigned long long fract A) - -- Runtime Function: long accum __satfractudqda (unsigned long long - fract A) - -- Runtime Function: long long accum __satfractudqta (unsigned long - long fract A) - -- Runtime Function: unsigned short fract __satfractudquqq2 (unsigned - long long fract A) - -- Runtime Function: unsigned fract __satfractudquhq2 (unsigned long - long fract A) - -- Runtime Function: unsigned long fract __satfractudqusq2 (unsigned - long long fract A) - -- Runtime Function: unsigned short accum __satfractudquha (unsigned - long long fract A) - -- Runtime Function: unsigned accum __satfractudqusa (unsigned long - long fract A) - -- Runtime Function: unsigned long accum __satfractudquda (unsigned - long long fract A) - -- Runtime Function: unsigned long long accum __satfractudquta - (unsigned long long fract A) - -- Runtime Function: short fract __satfractuhaqq (unsigned short accum - A) - -- Runtime Function: fract __satfractuhahq (unsigned short accum A) - -- Runtime Function: long fract __satfractuhasq (unsigned short accum - A) - -- Runtime Function: long long fract __satfractuhadq (unsigned short - accum A) - -- Runtime Function: short accum __satfractuhaha (unsigned short accum - A) - -- Runtime Function: accum __satfractuhasa (unsigned short accum A) - -- Runtime Function: long accum __satfractuhada (unsigned short accum - A) - -- Runtime Function: long long accum __satfractuhata (unsigned short - accum A) - -- Runtime Function: unsigned short fract __satfractuhauqq (unsigned - short accum A) - -- Runtime Function: unsigned fract __satfractuhauhq (unsigned short - accum A) - -- Runtime Function: unsigned long fract __satfractuhausq (unsigned - short accum A) - -- Runtime Function: unsigned long long fract __satfractuhaudq - (unsigned short accum A) - -- Runtime Function: unsigned accum __satfractuhausa2 (unsigned short - accum A) - -- Runtime Function: unsigned long accum __satfractuhauda2 (unsigned - short accum A) - -- Runtime Function: unsigned long long accum __satfractuhauta2 - (unsigned short accum A) - -- Runtime Function: short fract __satfractusaqq (unsigned accum A) - -- Runtime Function: fract __satfractusahq (unsigned accum A) - -- Runtime Function: long fract __satfractusasq (unsigned accum A) - -- Runtime Function: long long fract __satfractusadq (unsigned accum A) - -- Runtime Function: short accum __satfractusaha (unsigned accum A) - -- Runtime Function: accum __satfractusasa (unsigned accum A) - -- Runtime Function: long accum __satfractusada (unsigned accum A) - -- Runtime Function: long long accum __satfractusata (unsigned accum A) - -- Runtime Function: unsigned short fract __satfractusauqq (unsigned - accum A) - -- Runtime Function: unsigned fract __satfractusauhq (unsigned accum A) - -- Runtime Function: unsigned long fract __satfractusausq (unsigned - accum A) - -- Runtime Function: unsigned long long fract __satfractusaudq - (unsigned accum A) - -- Runtime Function: unsigned short accum __satfractusauha2 (unsigned - accum A) - -- Runtime Function: unsigned long accum __satfractusauda2 (unsigned - accum A) - -- Runtime Function: unsigned long long accum __satfractusauta2 - (unsigned accum A) - -- Runtime Function: short fract __satfractudaqq (unsigned long accum - A) - -- Runtime Function: fract __satfractudahq (unsigned long accum A) - -- Runtime Function: long fract __satfractudasq (unsigned long accum A) - -- Runtime Function: long long fract __satfractudadq (unsigned long - accum A) - -- Runtime Function: short accum __satfractudaha (unsigned long accum - A) - -- Runtime Function: accum __satfractudasa (unsigned long accum A) - -- Runtime Function: long accum __satfractudada (unsigned long accum A) - -- Runtime Function: long long accum __satfractudata (unsigned long - accum A) - -- Runtime Function: unsigned short fract __satfractudauqq (unsigned - long accum A) - -- Runtime Function: unsigned fract __satfractudauhq (unsigned long - accum A) - -- Runtime Function: unsigned long fract __satfractudausq (unsigned - long accum A) - -- Runtime Function: unsigned long long fract __satfractudaudq - (unsigned long accum A) - -- Runtime Function: unsigned short accum __satfractudauha2 (unsigned - long accum A) - -- Runtime Function: unsigned accum __satfractudausa2 (unsigned long - accum A) - -- Runtime Function: unsigned long long accum __satfractudauta2 - (unsigned long accum A) - -- Runtime Function: short fract __satfractutaqq (unsigned long long - accum A) - -- Runtime Function: fract __satfractutahq (unsigned long long accum A) - -- Runtime Function: long fract __satfractutasq (unsigned long long - accum A) - -- Runtime Function: long long fract __satfractutadq (unsigned long - long accum A) - -- Runtime Function: short accum __satfractutaha (unsigned long long - accum A) - -- Runtime Function: accum __satfractutasa (unsigned long long accum A) - -- Runtime Function: long accum __satfractutada (unsigned long long - accum A) - -- Runtime Function: long long accum __satfractutata (unsigned long - long accum A) - -- Runtime Function: unsigned short fract __satfractutauqq (unsigned - long long accum A) - -- Runtime Function: unsigned fract __satfractutauhq (unsigned long - long accum A) - -- Runtime Function: unsigned long fract __satfractutausq (unsigned - long long accum A) - -- Runtime Function: unsigned long long fract __satfractutaudq - (unsigned long long accum A) - -- Runtime Function: unsigned short accum __satfractutauha2 (unsigned - long long accum A) - -- Runtime Function: unsigned accum __satfractutausa2 (unsigned long - long accum A) - -- Runtime Function: unsigned long accum __satfractutauda2 (unsigned - long long accum A) - -- Runtime Function: short fract __satfractqiqq (signed char A) - -- Runtime Function: fract __satfractqihq (signed char A) - -- Runtime Function: long fract __satfractqisq (signed char A) - -- Runtime Function: long long fract __satfractqidq (signed char A) - -- Runtime Function: short accum __satfractqiha (signed char A) - -- Runtime Function: accum __satfractqisa (signed char A) - -- Runtime Function: long accum __satfractqida (signed char A) - -- Runtime Function: long long accum __satfractqita (signed char A) - -- Runtime Function: unsigned short fract __satfractqiuqq (signed char - A) - -- Runtime Function: unsigned fract __satfractqiuhq (signed char A) - -- Runtime Function: unsigned long fract __satfractqiusq (signed char - A) - -- Runtime Function: unsigned long long fract __satfractqiudq (signed - char A) - -- Runtime Function: unsigned short accum __satfractqiuha (signed char - A) - -- Runtime Function: unsigned accum __satfractqiusa (signed char A) - -- Runtime Function: unsigned long accum __satfractqiuda (signed char - A) - -- Runtime Function: unsigned long long accum __satfractqiuta (signed - char A) - -- Runtime Function: short fract __satfracthiqq (short A) - -- Runtime Function: fract __satfracthihq (short A) - -- Runtime Function: long fract __satfracthisq (short A) - -- Runtime Function: long long fract __satfracthidq (short A) - -- Runtime Function: short accum __satfracthiha (short A) - -- Runtime Function: accum __satfracthisa (short A) - -- Runtime Function: long accum __satfracthida (short A) - -- Runtime Function: long long accum __satfracthita (short A) - -- Runtime Function: unsigned short fract __satfracthiuqq (short A) - -- Runtime Function: unsigned fract __satfracthiuhq (short A) - -- Runtime Function: unsigned long fract __satfracthiusq (short A) - -- Runtime Function: unsigned long long fract __satfracthiudq (short A) - -- Runtime Function: unsigned short accum __satfracthiuha (short A) - -- Runtime Function: unsigned accum __satfracthiusa (short A) - -- Runtime Function: unsigned long accum __satfracthiuda (short A) - -- Runtime Function: unsigned long long accum __satfracthiuta (short A) - -- Runtime Function: short fract __satfractsiqq (int A) - -- Runtime Function: fract __satfractsihq (int A) - -- Runtime Function: long fract __satfractsisq (int A) - -- Runtime Function: long long fract __satfractsidq (int A) - -- Runtime Function: short accum __satfractsiha (int A) - -- Runtime Function: accum __satfractsisa (int A) - -- Runtime Function: long accum __satfractsida (int A) - -- Runtime Function: long long accum __satfractsita (int A) - -- Runtime Function: unsigned short fract __satfractsiuqq (int A) - -- Runtime Function: unsigned fract __satfractsiuhq (int A) - -- Runtime Function: unsigned long fract __satfractsiusq (int A) - -- Runtime Function: unsigned long long fract __satfractsiudq (int A) - -- Runtime Function: unsigned short accum __satfractsiuha (int A) - -- Runtime Function: unsigned accum __satfractsiusa (int A) - -- Runtime Function: unsigned long accum __satfractsiuda (int A) - -- Runtime Function: unsigned long long accum __satfractsiuta (int A) - -- Runtime Function: short fract __satfractdiqq (long A) - -- Runtime Function: fract __satfractdihq (long A) - -- Runtime Function: long fract __satfractdisq (long A) - -- Runtime Function: long long fract __satfractdidq (long A) - -- Runtime Function: short accum __satfractdiha (long A) - -- Runtime Function: accum __satfractdisa (long A) - -- Runtime Function: long accum __satfractdida (long A) - -- Runtime Function: long long accum __satfractdita (long A) - -- Runtime Function: unsigned short fract __satfractdiuqq (long A) - -- Runtime Function: unsigned fract __satfractdiuhq (long A) - -- Runtime Function: unsigned long fract __satfractdiusq (long A) - -- Runtime Function: unsigned long long fract __satfractdiudq (long A) - -- Runtime Function: unsigned short accum __satfractdiuha (long A) - -- Runtime Function: unsigned accum __satfractdiusa (long A) - -- Runtime Function: unsigned long accum __satfractdiuda (long A) - -- Runtime Function: unsigned long long accum __satfractdiuta (long A) - -- Runtime Function: short fract __satfracttiqq (long long A) - -- Runtime Function: fract __satfracttihq (long long A) - -- Runtime Function: long fract __satfracttisq (long long A) - -- Runtime Function: long long fract __satfracttidq (long long A) - -- Runtime Function: short accum __satfracttiha (long long A) - -- Runtime Function: accum __satfracttisa (long long A) - -- Runtime Function: long accum __satfracttida (long long A) - -- Runtime Function: long long accum __satfracttita (long long A) - -- Runtime Function: unsigned short fract __satfracttiuqq (long long A) - -- Runtime Function: unsigned fract __satfracttiuhq (long long A) - -- Runtime Function: unsigned long fract __satfracttiusq (long long A) - -- Runtime Function: unsigned long long fract __satfracttiudq (long - long A) - -- Runtime Function: unsigned short accum __satfracttiuha (long long A) - -- Runtime Function: unsigned accum __satfracttiusa (long long A) - -- Runtime Function: unsigned long accum __satfracttiuda (long long A) - -- Runtime Function: unsigned long long accum __satfracttiuta (long - long A) - -- Runtime Function: short fract __satfractsfqq (float A) - -- Runtime Function: fract __satfractsfhq (float A) - -- Runtime Function: long fract __satfractsfsq (float A) - -- Runtime Function: long long fract __satfractsfdq (float A) - -- Runtime Function: short accum __satfractsfha (float A) - -- Runtime Function: accum __satfractsfsa (float A) - -- Runtime Function: long accum __satfractsfda (float A) - -- Runtime Function: long long accum __satfractsfta (float A) - -- Runtime Function: unsigned short fract __satfractsfuqq (float A) - -- Runtime Function: unsigned fract __satfractsfuhq (float A) - -- Runtime Function: unsigned long fract __satfractsfusq (float A) - -- Runtime Function: unsigned long long fract __satfractsfudq (float A) - -- Runtime Function: unsigned short accum __satfractsfuha (float A) - -- Runtime Function: unsigned accum __satfractsfusa (float A) - -- Runtime Function: unsigned long accum __satfractsfuda (float A) - -- Runtime Function: unsigned long long accum __satfractsfuta (float A) - -- Runtime Function: short fract __satfractdfqq (double A) - -- Runtime Function: fract __satfractdfhq (double A) - -- Runtime Function: long fract __satfractdfsq (double A) - -- Runtime Function: long long fract __satfractdfdq (double A) - -- Runtime Function: short accum __satfractdfha (double A) - -- Runtime Function: accum __satfractdfsa (double A) - -- Runtime Function: long accum __satfractdfda (double A) - -- Runtime Function: long long accum __satfractdfta (double A) - -- Runtime Function: unsigned short fract __satfractdfuqq (double A) - -- Runtime Function: unsigned fract __satfractdfuhq (double A) - -- Runtime Function: unsigned long fract __satfractdfusq (double A) - -- Runtime Function: unsigned long long fract __satfractdfudq (double - A) - -- Runtime Function: unsigned short accum __satfractdfuha (double A) - -- Runtime Function: unsigned accum __satfractdfusa (double A) - -- Runtime Function: unsigned long accum __satfractdfuda (double A) - -- Runtime Function: unsigned long long accum __satfractdfuta (double - A) - The functions convert from fractional and signed non-fractionals to - fractionals, with saturation. - - -- Runtime Function: unsigned char __fractunsqqqi (short fract A) - -- Runtime Function: unsigned short __fractunsqqhi (short fract A) - -- Runtime Function: unsigned int __fractunsqqsi (short fract A) - -- Runtime Function: unsigned long __fractunsqqdi (short fract A) - -- Runtime Function: unsigned long long __fractunsqqti (short fract A) - -- Runtime Function: unsigned char __fractunshqqi (fract A) - -- Runtime Function: unsigned short __fractunshqhi (fract A) - -- Runtime Function: unsigned int __fractunshqsi (fract A) - -- Runtime Function: unsigned long __fractunshqdi (fract A) - -- Runtime Function: unsigned long long __fractunshqti (fract A) - -- Runtime Function: unsigned char __fractunssqqi (long fract A) - -- Runtime Function: unsigned short __fractunssqhi (long fract A) - -- Runtime Function: unsigned int __fractunssqsi (long fract A) - -- Runtime Function: unsigned long __fractunssqdi (long fract A) - -- Runtime Function: unsigned long long __fractunssqti (long fract A) - -- Runtime Function: unsigned char __fractunsdqqi (long long fract A) - -- Runtime Function: unsigned short __fractunsdqhi (long long fract A) - -- Runtime Function: unsigned int __fractunsdqsi (long long fract A) - -- Runtime Function: unsigned long __fractunsdqdi (long long fract A) - -- Runtime Function: unsigned long long __fractunsdqti (long long fract - A) - -- Runtime Function: unsigned char __fractunshaqi (short accum A) - -- Runtime Function: unsigned short __fractunshahi (short accum A) - -- Runtime Function: unsigned int __fractunshasi (short accum A) - -- Runtime Function: unsigned long __fractunshadi (short accum A) - -- Runtime Function: unsigned long long __fractunshati (short accum A) - -- Runtime Function: unsigned char __fractunssaqi (accum A) - -- Runtime Function: unsigned short __fractunssahi (accum A) - -- Runtime Function: unsigned int __fractunssasi (accum A) - -- Runtime Function: unsigned long __fractunssadi (accum A) - -- Runtime Function: unsigned long long __fractunssati (accum A) - -- Runtime Function: unsigned char __fractunsdaqi (long accum A) - -- Runtime Function: unsigned short __fractunsdahi (long accum A) - -- Runtime Function: unsigned int __fractunsdasi (long accum A) - -- Runtime Function: unsigned long __fractunsdadi (long accum A) - -- Runtime Function: unsigned long long __fractunsdati (long accum A) - -- Runtime Function: unsigned char __fractunstaqi (long long accum A) - -- Runtime Function: unsigned short __fractunstahi (long long accum A) - -- Runtime Function: unsigned int __fractunstasi (long long accum A) - -- Runtime Function: unsigned long __fractunstadi (long long accum A) - -- Runtime Function: unsigned long long __fractunstati (long long accum - A) - -- Runtime Function: unsigned char __fractunsuqqqi (unsigned short - fract A) - -- Runtime Function: unsigned short __fractunsuqqhi (unsigned short - fract A) - -- Runtime Function: unsigned int __fractunsuqqsi (unsigned short fract - A) - -- Runtime Function: unsigned long __fractunsuqqdi (unsigned short - fract A) - -- Runtime Function: unsigned long long __fractunsuqqti (unsigned short - fract A) - -- Runtime Function: unsigned char __fractunsuhqqi (unsigned fract A) - -- Runtime Function: unsigned short __fractunsuhqhi (unsigned fract A) - -- Runtime Function: unsigned int __fractunsuhqsi (unsigned fract A) - -- Runtime Function: unsigned long __fractunsuhqdi (unsigned fract A) - -- Runtime Function: unsigned long long __fractunsuhqti (unsigned fract - A) - -- Runtime Function: unsigned char __fractunsusqqi (unsigned long fract - A) - -- Runtime Function: unsigned short __fractunsusqhi (unsigned long - fract A) - -- Runtime Function: unsigned int __fractunsusqsi (unsigned long fract - A) - -- Runtime Function: unsigned long __fractunsusqdi (unsigned long fract - A) - -- Runtime Function: unsigned long long __fractunsusqti (unsigned long - fract A) - -- Runtime Function: unsigned char __fractunsudqqi (unsigned long long - fract A) - -- Runtime Function: unsigned short __fractunsudqhi (unsigned long long - fract A) - -- Runtime Function: unsigned int __fractunsudqsi (unsigned long long - fract A) - -- Runtime Function: unsigned long __fractunsudqdi (unsigned long long - fract A) - -- Runtime Function: unsigned long long __fractunsudqti (unsigned long - long fract A) - -- Runtime Function: unsigned char __fractunsuhaqi (unsigned short - accum A) - -- Runtime Function: unsigned short __fractunsuhahi (unsigned short - accum A) - -- Runtime Function: unsigned int __fractunsuhasi (unsigned short accum - A) - -- Runtime Function: unsigned long __fractunsuhadi (unsigned short - accum A) - -- Runtime Function: unsigned long long __fractunsuhati (unsigned short - accum A) - -- Runtime Function: unsigned char __fractunsusaqi (unsigned accum A) - -- Runtime Function: unsigned short __fractunsusahi (unsigned accum A) - -- Runtime Function: unsigned int __fractunsusasi (unsigned accum A) - -- Runtime Function: unsigned long __fractunsusadi (unsigned accum A) - -- Runtime Function: unsigned long long __fractunsusati (unsigned accum - A) - -- Runtime Function: unsigned char __fractunsudaqi (unsigned long accum - A) - -- Runtime Function: unsigned short __fractunsudahi (unsigned long - accum A) - -- Runtime Function: unsigned int __fractunsudasi (unsigned long accum - A) - -- Runtime Function: unsigned long __fractunsudadi (unsigned long accum - A) - -- Runtime Function: unsigned long long __fractunsudati (unsigned long - accum A) - -- Runtime Function: unsigned char __fractunsutaqi (unsigned long long - accum A) - -- Runtime Function: unsigned short __fractunsutahi (unsigned long long - accum A) - -- Runtime Function: unsigned int __fractunsutasi (unsigned long long - accum A) - -- Runtime Function: unsigned long __fractunsutadi (unsigned long long - accum A) - -- Runtime Function: unsigned long long __fractunsutati (unsigned long - long accum A) - -- Runtime Function: short fract __fractunsqiqq (unsigned char A) - -- Runtime Function: fract __fractunsqihq (unsigned char A) - -- Runtime Function: long fract __fractunsqisq (unsigned char A) - -- Runtime Function: long long fract __fractunsqidq (unsigned char A) - -- Runtime Function: short accum __fractunsqiha (unsigned char A) - -- Runtime Function: accum __fractunsqisa (unsigned char A) - -- Runtime Function: long accum __fractunsqida (unsigned char A) - -- Runtime Function: long long accum __fractunsqita (unsigned char A) - -- Runtime Function: unsigned short fract __fractunsqiuqq (unsigned - char A) - -- Runtime Function: unsigned fract __fractunsqiuhq (unsigned char A) - -- Runtime Function: unsigned long fract __fractunsqiusq (unsigned char - A) - -- Runtime Function: unsigned long long fract __fractunsqiudq (unsigned - char A) - -- Runtime Function: unsigned short accum __fractunsqiuha (unsigned - char A) - -- Runtime Function: unsigned accum __fractunsqiusa (unsigned char A) - -- Runtime Function: unsigned long accum __fractunsqiuda (unsigned char - A) - -- Runtime Function: unsigned long long accum __fractunsqiuta (unsigned - char A) - -- Runtime Function: short fract __fractunshiqq (unsigned short A) - -- Runtime Function: fract __fractunshihq (unsigned short A) - -- Runtime Function: long fract __fractunshisq (unsigned short A) - -- Runtime Function: long long fract __fractunshidq (unsigned short A) - -- Runtime Function: short accum __fractunshiha (unsigned short A) - -- Runtime Function: accum __fractunshisa (unsigned short A) - -- Runtime Function: long accum __fractunshida (unsigned short A) - -- Runtime Function: long long accum __fractunshita (unsigned short A) - -- Runtime Function: unsigned short fract __fractunshiuqq (unsigned - short A) - -- Runtime Function: unsigned fract __fractunshiuhq (unsigned short A) - -- Runtime Function: unsigned long fract __fractunshiusq (unsigned - short A) - -- Runtime Function: unsigned long long fract __fractunshiudq (unsigned - short A) - -- Runtime Function: unsigned short accum __fractunshiuha (unsigned - short A) - -- Runtime Function: unsigned accum __fractunshiusa (unsigned short A) - -- Runtime Function: unsigned long accum __fractunshiuda (unsigned - short A) - -- Runtime Function: unsigned long long accum __fractunshiuta (unsigned - short A) - -- Runtime Function: short fract __fractunssiqq (unsigned int A) - -- Runtime Function: fract __fractunssihq (unsigned int A) - -- Runtime Function: long fract __fractunssisq (unsigned int A) - -- Runtime Function: long long fract __fractunssidq (unsigned int A) - -- Runtime Function: short accum __fractunssiha (unsigned int A) - -- Runtime Function: accum __fractunssisa (unsigned int A) - -- Runtime Function: long accum __fractunssida (unsigned int A) - -- Runtime Function: long long accum __fractunssita (unsigned int A) - -- Runtime Function: unsigned short fract __fractunssiuqq (unsigned int - A) - -- Runtime Function: unsigned fract __fractunssiuhq (unsigned int A) - -- Runtime Function: unsigned long fract __fractunssiusq (unsigned int - A) - -- Runtime Function: unsigned long long fract __fractunssiudq (unsigned - int A) - -- Runtime Function: unsigned short accum __fractunssiuha (unsigned int - A) - -- Runtime Function: unsigned accum __fractunssiusa (unsigned int A) - -- Runtime Function: unsigned long accum __fractunssiuda (unsigned int - A) - -- Runtime Function: unsigned long long accum __fractunssiuta (unsigned - int A) - -- Runtime Function: short fract __fractunsdiqq (unsigned long A) - -- Runtime Function: fract __fractunsdihq (unsigned long A) - -- Runtime Function: long fract __fractunsdisq (unsigned long A) - -- Runtime Function: long long fract __fractunsdidq (unsigned long A) - -- Runtime Function: short accum __fractunsdiha (unsigned long A) - -- Runtime Function: accum __fractunsdisa (unsigned long A) - -- Runtime Function: long accum __fractunsdida (unsigned long A) - -- Runtime Function: long long accum __fractunsdita (unsigned long A) - -- Runtime Function: unsigned short fract __fractunsdiuqq (unsigned - long A) - -- Runtime Function: unsigned fract __fractunsdiuhq (unsigned long A) - -- Runtime Function: unsigned long fract __fractunsdiusq (unsigned long - A) - -- Runtime Function: unsigned long long fract __fractunsdiudq (unsigned - long A) - -- Runtime Function: unsigned short accum __fractunsdiuha (unsigned - long A) - -- Runtime Function: unsigned accum __fractunsdiusa (unsigned long A) - -- Runtime Function: unsigned long accum __fractunsdiuda (unsigned long - A) - -- Runtime Function: unsigned long long accum __fractunsdiuta (unsigned - long A) - -- Runtime Function: short fract __fractunstiqq (unsigned long long A) - -- Runtime Function: fract __fractunstihq (unsigned long long A) - -- Runtime Function: long fract __fractunstisq (unsigned long long A) - -- Runtime Function: long long fract __fractunstidq (unsigned long long - A) - -- Runtime Function: short accum __fractunstiha (unsigned long long A) - -- Runtime Function: accum __fractunstisa (unsigned long long A) - -- Runtime Function: long accum __fractunstida (unsigned long long A) - -- Runtime Function: long long accum __fractunstita (unsigned long long - A) - -- Runtime Function: unsigned short fract __fractunstiuqq (unsigned - long long A) - -- Runtime Function: unsigned fract __fractunstiuhq (unsigned long long - A) - -- Runtime Function: unsigned long fract __fractunstiusq (unsigned long - long A) - -- Runtime Function: unsigned long long fract __fractunstiudq (unsigned - long long A) - -- Runtime Function: unsigned short accum __fractunstiuha (unsigned - long long A) - -- Runtime Function: unsigned accum __fractunstiusa (unsigned long long - A) - -- Runtime Function: unsigned long accum __fractunstiuda (unsigned long - long A) - -- Runtime Function: unsigned long long accum __fractunstiuta (unsigned - long long A) - These functions convert from fractionals to unsigned - non-fractionals; and from unsigned non-fractionals to fractionals, - without saturation. - - -- Runtime Function: short fract __satfractunsqiqq (unsigned char A) - -- Runtime Function: fract __satfractunsqihq (unsigned char A) - -- Runtime Function: long fract __satfractunsqisq (unsigned char A) - -- Runtime Function: long long fract __satfractunsqidq (unsigned char - A) - -- Runtime Function: short accum __satfractunsqiha (unsigned char A) - -- Runtime Function: accum __satfractunsqisa (unsigned char A) - -- Runtime Function: long accum __satfractunsqida (unsigned char A) - -- Runtime Function: long long accum __satfractunsqita (unsigned char - A) - -- Runtime Function: unsigned short fract __satfractunsqiuqq (unsigned - char A) - -- Runtime Function: unsigned fract __satfractunsqiuhq (unsigned char - A) - -- Runtime Function: unsigned long fract __satfractunsqiusq (unsigned - char A) - -- Runtime Function: unsigned long long fract __satfractunsqiudq - (unsigned char A) - -- Runtime Function: unsigned short accum __satfractunsqiuha (unsigned - char A) - -- Runtime Function: unsigned accum __satfractunsqiusa (unsigned char - A) - -- Runtime Function: unsigned long accum __satfractunsqiuda (unsigned - char A) - -- Runtime Function: unsigned long long accum __satfractunsqiuta - (unsigned char A) - -- Runtime Function: short fract __satfractunshiqq (unsigned short A) - -- Runtime Function: fract __satfractunshihq (unsigned short A) - -- Runtime Function: long fract __satfractunshisq (unsigned short A) - -- Runtime Function: long long fract __satfractunshidq (unsigned short - A) - -- Runtime Function: short accum __satfractunshiha (unsigned short A) - -- Runtime Function: accum __satfractunshisa (unsigned short A) - -- Runtime Function: long accum __satfractunshida (unsigned short A) - -- Runtime Function: long long accum __satfractunshita (unsigned short - A) - -- Runtime Function: unsigned short fract __satfractunshiuqq (unsigned - short A) - -- Runtime Function: unsigned fract __satfractunshiuhq (unsigned short - A) - -- Runtime Function: unsigned long fract __satfractunshiusq (unsigned - short A) - -- Runtime Function: unsigned long long fract __satfractunshiudq - (unsigned short A) - -- Runtime Function: unsigned short accum __satfractunshiuha (unsigned - short A) - -- Runtime Function: unsigned accum __satfractunshiusa (unsigned short - A) - -- Runtime Function: unsigned long accum __satfractunshiuda (unsigned - short A) - -- Runtime Function: unsigned long long accum __satfractunshiuta - (unsigned short A) - -- Runtime Function: short fract __satfractunssiqq (unsigned int A) - -- Runtime Function: fract __satfractunssihq (unsigned int A) - -- Runtime Function: long fract __satfractunssisq (unsigned int A) - -- Runtime Function: long long fract __satfractunssidq (unsigned int A) - -- Runtime Function: short accum __satfractunssiha (unsigned int A) - -- Runtime Function: accum __satfractunssisa (unsigned int A) - -- Runtime Function: long accum __satfractunssida (unsigned int A) - -- Runtime Function: long long accum __satfractunssita (unsigned int A) - -- Runtime Function: unsigned short fract __satfractunssiuqq (unsigned - int A) - -- Runtime Function: unsigned fract __satfractunssiuhq (unsigned int A) - -- Runtime Function: unsigned long fract __satfractunssiusq (unsigned - int A) - -- Runtime Function: unsigned long long fract __satfractunssiudq - (unsigned int A) - -- Runtime Function: unsigned short accum __satfractunssiuha (unsigned - int A) - -- Runtime Function: unsigned accum __satfractunssiusa (unsigned int A) - -- Runtime Function: unsigned long accum __satfractunssiuda (unsigned - int A) - -- Runtime Function: unsigned long long accum __satfractunssiuta - (unsigned int A) - -- Runtime Function: short fract __satfractunsdiqq (unsigned long A) - -- Runtime Function: fract __satfractunsdihq (unsigned long A) - -- Runtime Function: long fract __satfractunsdisq (unsigned long A) - -- Runtime Function: long long fract __satfractunsdidq (unsigned long - A) - -- Runtime Function: short accum __satfractunsdiha (unsigned long A) - -- Runtime Function: accum __satfractunsdisa (unsigned long A) - -- Runtime Function: long accum __satfractunsdida (unsigned long A) - -- Runtime Function: long long accum __satfractunsdita (unsigned long - A) - -- Runtime Function: unsigned short fract __satfractunsdiuqq (unsigned - long A) - -- Runtime Function: unsigned fract __satfractunsdiuhq (unsigned long - A) - -- Runtime Function: unsigned long fract __satfractunsdiusq (unsigned - long A) - -- Runtime Function: unsigned long long fract __satfractunsdiudq - (unsigned long A) - -- Runtime Function: unsigned short accum __satfractunsdiuha (unsigned - long A) - -- Runtime Function: unsigned accum __satfractunsdiusa (unsigned long - A) - -- Runtime Function: unsigned long accum __satfractunsdiuda (unsigned - long A) - -- Runtime Function: unsigned long long accum __satfractunsdiuta - (unsigned long A) - -- Runtime Function: short fract __satfractunstiqq (unsigned long long - A) - -- Runtime Function: fract __satfractunstihq (unsigned long long A) - -- Runtime Function: long fract __satfractunstisq (unsigned long long - A) - -- Runtime Function: long long fract __satfractunstidq (unsigned long - long A) - -- Runtime Function: short accum __satfractunstiha (unsigned long long - A) - -- Runtime Function: accum __satfractunstisa (unsigned long long A) - -- Runtime Function: long accum __satfractunstida (unsigned long long - A) - -- Runtime Function: long long accum __satfractunstita (unsigned long - long A) - -- Runtime Function: unsigned short fract __satfractunstiuqq (unsigned - long long A) - -- Runtime Function: unsigned fract __satfractunstiuhq (unsigned long - long A) - -- Runtime Function: unsigned long fract __satfractunstiusq (unsigned - long long A) - -- Runtime Function: unsigned long long fract __satfractunstiudq - (unsigned long long A) - -- Runtime Function: unsigned short accum __satfractunstiuha (unsigned - long long A) - -- Runtime Function: unsigned accum __satfractunstiusa (unsigned long - long A) - -- Runtime Function: unsigned long accum __satfractunstiuda (unsigned - long long A) - -- Runtime Function: unsigned long long accum __satfractunstiuta - (unsigned long long A) - These functions convert from unsigned non-fractionals to - fractionals, with saturation. - - -File: gccint.info, Node: Exception handling routines, Next: Miscellaneous routines, Prev: Fixed-point fractional library routines, Up: Libgcc - -4.5 Language-independent routines for exception handling -======================================================== - -document me! - - _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 - - -File: gccint.info, Node: Miscellaneous routines, Prev: Exception handling routines, Up: Libgcc - -4.6 Miscellaneous runtime library routines -========================================== - -4.6.1 Cache control functions ------------------------------ - - -- Runtime Function: void __clear_cache (char *BEG, char *END) - This function clears the instruction cache between BEG and END. - -4.6.2 Split stack functions and variables ------------------------------------------ - - -- Runtime Function: void * __splitstack_find (void *SEGMENT_ARG, void - *SP, size_t LEN, void **NEXT_SEGMENT, void **NEXT_SP, void - **INITIAL_SP) - When using '-fsplit-stack', this call may be used to iterate over - the stack segments. It may be called like this: - void *next_segment = NULL; - void *next_sp = NULL; - void *initial_sp = NULL; - void *stack; - size_t stack_size; - while ((stack = __splitstack_find (next_segment, next_sp, - &stack_size, &next_segment, - &next_sp, &initial_sp)) - != NULL) - { - /* Stack segment starts at stack and is - stack_size bytes long. */ - } - - There is no way to iterate over the stack segments of a different - thread. However, what is permitted is for one thread to call this - with the SEGMENT_ARG and SP arguments NULL, to pass NEXT_SEGMENT, - NEXT_SP, and INITIAL_SP to a different thread, and then to suspend - one way or another. A different thread may run the subsequent - '__splitstack_find' iterations. Of course, this will only work if - the first thread is suspended while the second thread is calling - '__splitstack_find'. If not, the second thread could be looking at - the stack while it is changing, and anything could happen. - - -- Variable: __morestack_segments - -- Variable: __morestack_current_segment - -- Variable: __morestack_initial_sp - Internal variables used by the '-fsplit-stack' implementation. - - -File: gccint.info, Node: Languages, Next: Source Tree, Prev: Libgcc, Up: Top - -5 Language Front Ends in GCC -**************************** - -The interface to front ends for languages in GCC, and in particular the -'tree' structure (*note GENERIC::), 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: - - * GCC front ends benefit from the support for many different target - machines already present in GCC. - * 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. - * Better debugging information is generated when compiling directly - from source code than when going via intermediate generated C code. - - 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. - - -File: gccint.info, Node: Source Tree, Next: Testsuites, Prev: Languages, Up: Top - -6 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 (<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 'gcc' subdirectory. - - -File: gccint.info, Node: Configure Terms, Next: Top Level, Up: Source Tree - -6.1 Configure Terms and History -=============================== - -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 ("build"), the machine that you are building for -("host"), and the machine that GCC will produce code for ("target"). -When you configure GCC, you specify these with '--build=', '--host=', -and '--target='. - - Specifying the host without specifying the build should be avoided, as -'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 "native". -If build and host are the same but target is different, this is called a -"cross". If build, host, and target are all different this is called a -"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 "host-x-host", "crossed native", or "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 "crossback". - - If build and host are the same, the GCC you are building will also be -used to build the target libraries (like 'libstdc++'). If build and -host are different, you must have already built and installed a cross -compiler that will be used to build the target libraries (if you -configured with '--target=foo-bar', this compiler will be called -'foo-bar-gcc'). - - In the case of target libraries, the machine you're building for is the -machine you specified with '--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 '$with_cross_host' to -the original '--host' value in case you need it. - - The '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. - - -File: gccint.info, Node: Top Level, Next: gcc Directory, Prev: Configure Terms, Up: Source Tree - -6.2 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: - -'boehm-gc' - The Boehm conservative garbage collector, used as part of the Java - runtime library. - -'config' - Autoconf macros and Makefile fragments used throughout the tree. - -'contrib' - Contributed scripts that may be found useful in conjunction with - GCC. One of these, 'contrib/texi2pod.pl', is used to generate man - pages from Texinfo manuals as part of the GCC build process. - -'fixincludes' - The support for fixing system headers to work with GCC. See - 'fixincludes/README' for more information. The headers fixed by - this mechanism are installed in 'LIBSUBDIR/include-fixed'. Along - with those headers, 'README-fixinc' is also installed, as - 'LIBSUBDIR/include-fixed/README'. - -'gcc' - The main sources of GCC itself (except for runtime libraries), - including optimizers, support for different target architectures, - language front ends, and testsuites. *Note The 'gcc' Subdirectory: - gcc Directory, for details. - -'gnattools' - Support tools for GNAT. - -'include' - Headers for the 'libiberty' library. - -'intl' - GNU 'libintl', from GNU 'gettext', for systems which do not include - it in 'libc'. - -'libada' - The Ada runtime library. - -'libatomic' - The runtime support library for atomic operations (e.g. for - '__sync' and '__atomic'). - -'libcpp' - The C preprocessor library. - -'libdecnumber' - The Decimal Float support library. - -'libffi' - The 'libffi' library, used as part of the Java runtime library. - -'libgcc' - The GCC runtime library. - -'libgfortran' - The Fortran runtime library. - -'libgo' - The Go runtime library. The bulk of this library is mirrored from - the master Go repository (http://code.google.com/p/go/). - -'libgomp' - The GNU OpenMP runtime library. - -'libiberty' - The 'libiberty' library, used for portability and for some - generally useful data structures and algorithms. *Note - Introduction: (libiberty)Top, for more information about this - library. - -'libitm' - The runtime support library for transactional memory. - -'libjava' - The Java runtime library. - -'libobjc' - The Objective-C and Objective-C++ runtime library. - -'libquadmath' - The runtime support library for quad-precision math operations. - -'libssp' - The Stack protector runtime library. - -'libstdc++-v3' - The C++ runtime library. - -'lto-plugin' - Plugin used by the linker if link-time optimizations are enabled. - -'maintainer-scripts' - Scripts used by the 'gccadmin' account on 'gcc.gnu.org'. - -'zlib' - The 'zlib' compression library, used by the Java front end, as part - of the Java runtime library, and for compressing and uncompressing - GCC's intermediate language in LTO object files. - - 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. *Note GNU configure and build system: (configure)Top, for -details. - - -File: gccint.info, Node: gcc Directory, Prev: Top Level, Up: Source Tree - -6.3 The 'gcc' Subdirectory -========================== - -The '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. *Note -Passes and Files of the Compiler: Passes. - -* Menu: - -* Subdirectories:: Subdirectories of 'gcc'. -* Configuration:: The configuration process, and the files it uses. -* Build:: The build system in the 'gcc' directory. -* Makefile:: Targets in 'gcc/Makefile'. -* Library Files:: Library source files and headers under '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. - - -File: gccint.info, Node: Subdirectories, Next: Configuration, Up: gcc Directory - -6.3.1 Subdirectories of 'gcc' ------------------------------ - -The 'gcc' directory contains the following subdirectories: - -'LANGUAGE' - Subdirectories for various languages. Directories containing a - file 'config-lang.in' are language subdirectories. The contents of - the subdirectories 'c' (for C), 'cp' (for C++), 'objc' (for - Objective-C), 'objcp' (for Objective-C++), and 'lto' (for LTO) are - documented in this manual (*note Passes and Files of the Compiler: - Passes.); those for other languages are not. *Note Anatomy of a - Language Front End: Front End, for details of the files in these - directories. - -'common' - Source files shared between the compiler drivers (such as 'gcc') - and the compilers proper (such as 'cc1'). If an architecture - defines target hooks shared between those places, it also has a - subdirectory in 'common/config'. *Note Target Structure::. - -'config' - Configuration files for supported architectures and operating - systems. *Note Anatomy of a Target Back End: Back End, for details - of the files in this directory. - -'doc' - Texinfo documentation for GCC, together with automatically - generated man pages and support for converting the installation - manual to HTML. *Note Documentation::. - -'ginclude' - System headers installed by GCC, mainly those required by the C - standard of freestanding implementations. *Note Headers Installed - by GCC: Headers, for details of when these and other headers are - installed. - -'po' - Message catalogs with translations of messages produced by GCC into - various languages, 'LANGUAGE.po'. This directory also contains - 'gcc.pot', the template for these message catalogues, 'exgettext', - a wrapper around 'gettext' to extract the messages from the GCC - sources and create 'gcc.pot', which is run by 'make gcc.pot', and - 'EXCLUDES', a list of files from which messages should not be - extracted. - -'testsuite' - The GCC testsuites (except for those for runtime libraries). *Note - Testsuites::. - - -File: gccint.info, Node: Configuration, Next: Build, Prev: Subdirectories, Up: gcc Directory - -6.3.2 Configuration in the 'gcc' Directory ------------------------------------------- - -The 'gcc' directory is configured with an Autoconf-generated script -'configure'. The 'configure' script is generated from 'configure.ac' -and 'aclocal.m4'. From the files 'configure.ac' and 'acconfig.h', -Autoheader generates the file 'config.in'. The file 'cstamp-h.in' is -used as a timestamp. - -* Menu: - -* Config Fragments:: Scripts used by 'configure'. -* System Config:: The 'config.build', 'config.host', and - 'config.gcc' files. -* Configuration Files:: Files created by running 'configure'. - - -File: gccint.info, Node: Config Fragments, Next: System Config, Up: Configuration - -6.3.2.1 Scripts Used by 'configure' -................................... - -'configure' uses some other scripts to help in its work: - - * The standard GNU 'config.sub' and 'config.guess' files, kept in the - top level directory, are used. - - * The file 'config.gcc' is used to handle configuration specific to - the particular target machine. The file 'config.build' is used to - handle configuration specific to the particular build machine. The - 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.) *Note The 'config.build'; 'config.host'; and 'config.gcc' - Files: System Config, for details of the contents of these files. - - * Each language subdirectory has a file 'LANGUAGE/config-lang.in' - that is used for front-end-specific configuration. *Note The Front - End 'config-lang.in' File: Front End Config, for details of this - file. - - * A helper script 'configure.frag' is used as part of creating the - output of 'configure'. - - -File: gccint.info, Node: System Config, Next: Configuration Files, Prev: Config Fragments, Up: Configuration - -6.3.2.2 The 'config.build'; 'config.host'; and 'config.gcc' Files -................................................................. - -The '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 'config.host' file contains specific rules for particular systems -which GCC will run on. This is rarely needed. - - The '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. - - -File: gccint.info, Node: Configuration Files, Prev: System Config, Up: Configuration - -6.3.2.3 Files Created by 'configure' -.................................... - -Here we spell out what files will be set up by 'configure' in the '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. - - * 'Makefile' is constructed from 'Makefile.in', together with the - host and target fragments (*note Makefile Fragments: Fragments.) - 't-TARGET' and 'x-HOST' from 'config', if any, and language - Makefile fragments 'LANGUAGE/Make-lang.in'. - * 'auto-host.h' contains information about the host machine - determined by 'configure'. If the host machine is different from - the build machine, then 'auto-build.h' is also created, containing - such information about the build machine. - * 'config.status' is a script that may be run to recreate the current - configuration. - * 'configargs.h' is a header containing details of the arguments - passed to 'configure' to configure GCC, and of the thread model - used. - * 'cstamp-h' is used as a timestamp. - * If a language 'config-lang.in' file (*note The Front End - 'config-lang.in' File: Front End Config.) sets 'outputs', then the - files listed in 'outputs' there are also generated. - - The following configuration headers are created from the Makefile, -using 'mkconfig.sh', rather than directly by 'configure'. 'config.h', -'bconfig.h' and 'tconfig.h' all contain the 'xm-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 'configure'. The other configuration headers are -determined by 'config.gcc'. They also contain the typedefs for 'rtx', -'rtvec' and 'tree'. - - * 'config.h', for use in programs that run on the host machine. - * 'bconfig.h', for use in programs that run on the build machine. - * 'tconfig.h', for use in programs and libraries for the target - machine. - * 'tm_p.h', which includes the header 'MACHINE-protos.h' that - contains prototypes for functions in the target 'MACHINE.c' file. - The header 'MACHINE-protos.h' can include prototypes of functions - that use rtl and tree data structures inside appropriate '#ifdef - RTX_CODE' and '#ifdef TREE_CODE' conditional code segements. The - 'MACHINE-protos.h' is included after the 'rtl.h' and/or 'tree.h' - would have been included. The 'tm_p.h' also includes the header - 'tm-preds.h' which is generated by 'genpreds' program during the - build to define the declarations and inline functions for the - predicate functions. - - -File: gccint.info, Node: Build, Next: Makefile, Prev: Configuration, Up: gcc Directory - -6.3.3 Build System in the '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 (*note Passes::). - - -File: gccint.info, Node: Makefile, Next: Library Files, Prev: Build, Up: gcc Directory - -6.3.4 Makefile Targets ----------------------- - -These targets are available from the 'gcc' directory: - -'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. - -'doc' - Produce info-formatted documentation and man pages. Essentially it - calls 'make man' and 'make info'. - -'dvi' - Produce DVI-formatted documentation. - -'pdf' - Produce PDF-formatted documentation. - -'html' - Produce HTML-formatted documentation. - -'man' - Generate man pages. - -'info' - Generate info-formatted pages. - -'mostlyclean' - Delete the files made while building the compiler. - -'clean' - That, and all the other files built by 'make all'. - -'distclean' - That, and all the files created by 'configure'. - -'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. - -'srcextra' - Generates files in the source directory that are not - version-controlled but should go into a release tarball. - -'srcinfo' -'srcman' - Copies the info-formatted and manpage documentation into the source - directory usually for the purpose of generating a release tarball. - -'install' - Installs GCC. - -'uninstall' - Deletes installed files, though this is not supported. - -'check' - Run the testsuite. This creates a 'testsuite' subdirectory that - has various '.sum' and '.log' files containing the results of the - testing. You can run subsets with, for example, 'make check-gcc'. - You can specify specific tests by setting 'RUNTESTFLAGS' to be the - name of the '.exp' file, optionally followed by (for some tests) an - equals and a file wildcard, like: - - make check-gcc RUNTESTFLAGS="execute.exp=19980413-*" - - Note that running the testsuite may require additional tools be - installed, such as Tcl or DejaGnu. - - 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 '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 '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(1). - - Other targets available from the top level include: - -'bootstrap-lean' - Like 'bootstrap', except that the various stages are removed once - they're no longer needed. This saves disk space. - -'bootstrap2' -'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. - -'stageN-bubble (N = 1...4, profile, feedback)' - Rebuild all the stages up to N, with the appropriate flags, - "bubbling" the changes as described above. - -'all-stageN (N = 1...4, profile, feedback)' - Assuming that stage N has already been built, rebuild it with the - appropriate flags. This is rarely needed. - -'cleanstrap' - Remove everything ('make clean') and rebuilds ('make bootstrap'). - -'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. - -'profiledbootstrap' - Builds a compiler with profiling feedback information. In this - case, the second and third stages are named 'profile' and - 'feedback', respectively. For more information, see *note Building - with profile feedback: (gccinstall)Building. - -'restrap' - Restart a bootstrap, so that everything that was not built with the - system compiler is rebuilt. - -'stageN-start (N = 1...4, profile, feedback)' - For each package that is bootstrapped, rename directories so that, - for example, 'gcc' points to the stageN GCC, compiled with the - stageN-1 GCC(2). - - You will invoke this target if you need to test or debug the stageN - GCC. If you only need to execute GCC (but you need not run 'make' - either to rebuild it or to run test suites), you should be able to - work directly in the 'stageN-gcc' directory. This makes it easier - to debug multiple stages in parallel. - -'stage' - For each package that is bootstrapped, relocate its build directory - to indicate its stage. For example, if the 'gcc' directory points - to the stage2 GCC, after invoking this target it will be renamed to - 'stage2-gcc'. - - If you wish to use non-default GCC flags when compiling the stage2 and -stage3 compilers, set 'BOOT_CFLAGS' on the command line when doing -'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 'STAGE1_LANGUAGES' on the -command line when doing '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 - - make stage2-bubble STAGE1_LANGUAGES=c,fortran - - Alternatively, you can use per-language targets to build and test -languages that are not enabled by default in stage1. For example, 'make -f951' will build a Fortran compiler even in the stage1 build directory. - - ---------- Footnotes ---------- - - (1) Except if the compiler was buggy and miscompiled some of the -files that were not modified. In this case, it's best to use 'make -restrap'. - - (2) Customarily, the system compiler is also termed the 'stage0' GCC. - - -File: gccint.info, Node: Library Files, Next: Headers, Prev: Makefile, Up: gcc Directory - -6.3.5 Library Source Files and Headers under the 'gcc' Directory ----------------------------------------------------------------- - -FIXME: list here, with explanation, all the C source files and headers -under the 'gcc' directory that aren't built into the GCC executable but -rather are part of runtime libraries and object files, such as -'crtstuff.c' and 'unwind-dw2.c'. *Note Headers Installed by GCC: -Headers, for more information about the 'ginclude' directory. - - -File: gccint.info, Node: Headers, Next: Documentation, Prev: Library Files, Up: gcc Directory - -6.3.6 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 '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 'ginclude' directory. -These headers, 'iso646.h', 'stdarg.h', 'stdbool.h', and 'stddef.h', are -installed in 'LIBSUBDIR/include', unless the target Makefile fragment -(*note Target Fragment::) overrides this by setting '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 -'LIBSUBDIR/include'. 'config.gcc' may set 'extra_headers'; this -specifies additional headers under 'config' to be installed on some -systems. - - GCC installs its own version of '<float.h>', from '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 '<limits.h>'; this is generated -from 'glimits.h', together with 'limitx.h' and 'limity.h' if the system -also has its own version of '<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 -'<limits.h>'.) The system's '<limits.h>' header is used via -'LIBSUBDIR/include/syslimits.h', which is copied from 'gsyslimits.h' if -it does not need fixing to work with GCC; if it needs fixing, -'syslimits.h' is the fixed copy. - - GCC can also install '<tgmath.h>'. It will do this when 'config.gcc' -sets 'use_gcc_tgmath' to 'yes'. - - -File: gccint.info, Node: Documentation, Next: Front End, Prev: Headers, Up: gcc Directory - -6.3.7 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 -'make dvi', PDF versions by 'make pdf', and HTML versions by '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 '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. - - -File: gccint.info, Node: Texinfo Manuals, Next: Man Page Generation, Up: Documentation - -6.3.7.1 Texinfo Manuals -....................... - -The manuals for GCC as a whole, and the C and C++ front ends, are in -files 'doc/*.texi'. Other front ends have their own manuals in files -'LANGUAGE/*.texi'. Common files 'doc/include/*.texi' are provided which -may be included in multiple manuals; the following files are in -'doc/include': - -'fdl.texi' - The GNU Free Documentation License. -'funding.texi' - The section "Funding Free Software". -'gcc-common.texi' - Common definitions for manuals. -'gpl_v3.texi' - The GNU General Public License. -'texinfo.tex' - A copy of 'texinfo.tex' known to work with the GCC manuals. - - DVI-formatted manuals are generated by 'make dvi', which uses -'texi2dvi' (via the Makefile macro '$(TEXI2DVI)'). PDF-formatted -manuals are generated by 'make pdf', which uses 'texi2pdf' (via the -Makefile macro '$(TEXI2PDF)'). HTML formatted manuals are generated by -'make html'. Info manuals are generated by 'make info' (which is run as -part of a bootstrap); this generates the manuals in the source -directory, using 'makeinfo' via the Makefile macro '$(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 -'maintainer-scripts/update_web_docs_svn'. Each manual to be provided -online must be listed in the definition of 'MANUALS' in that file; a -file '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 'NAME.texi' should only include other -files in its own directory or in 'doc/include'. HTML manuals will be -generated by 'makeinfo --html', PostScript manuals by 'texi2dvi' and -'dvips', and PDF manuals by 'texi2pdf'. All Texinfo files that are -parts of manuals must be version-controlled, even if they are generated -files, for the generation of online manuals to work. - - The installation manual, 'doc/install.texi', is also provided on the -GCC web site. The HTML version is generated by the script -'doc/install.texi2html'. - - -File: gccint.info, Node: Man Page Generation, Next: Miscellaneous Docs, Prev: Texinfo Manuals, Up: Documentation - -6.3.7.2 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 'contrib/texi2pod.pl' and -'pod2man'. (The man page for 'g++', 'cp/g++.1', just contains a '.so' -reference to '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 '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 '@c man' control what parts of -a Texinfo file go into a man page. Only a subset of Texinfo is -supported by '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 -'doc/include/gcc-common.texi' which 'texi2pod.pl' understands: - -'@gcctabopt' - Use in the form '@table @gcctabopt' for tables of options, where - for printed output the effect of '@code' is better than that of - '@option' but for man page output a different effect is wanted. -'@gccoptlist' - Use for summary lists of options in manuals. -'@gol' - Use at the end of each line inside '@gccoptlist'. This is - necessary to avoid problems with differences in how the - '@gccoptlist' macro is handled by different Texinfo formatters. - - FIXME: describe the 'texi2pod.pl' input language and magic comments in -more detail. - - -File: gccint.info, Node: Miscellaneous Docs, Prev: Man Page Generation, Up: Documentation - -6.3.7.3 Miscellaneous Documentation -................................... - -In addition to the formal documentation that is installed by GCC, there -are several other text files in the 'gcc' subdirectory with -miscellaneous documentation: - -'ABOUT-GCC-NLS' - Notes on GCC's Native Language Support. FIXME: this should be part - of this manual rather than a separate file. -'ABOUT-NLS' - Notes on the Free Translation Project. -'COPYING' -'COPYING3' - The GNU General Public License, Versions 2 and 3. -'COPYING.LIB' -'COPYING3.LIB' - The GNU Lesser General Public License, Versions 2.1 and 3. -'*ChangeLog*' -'*/ChangeLog*' - Change log files for various parts of GCC. -'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. -'ONEWS' - Information about new features in old versions of GCC. (For recent - versions, the information is on the GCC web site.) -'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? - - FIXME: document such files in subdirectories, at least 'config', 'c', -'cp', 'objc', 'testsuite'. - - -File: gccint.info, Node: Front End, Next: Back End, Prev: Documentation, Up: gcc Directory - -6.3.8 Anatomy of a Language Front End -------------------------------------- - -A front end for a language in GCC has the following parts: - - * A directory 'LANGUAGE' under 'gcc' containing source files for that - front end. *Note The Front End 'LANGUAGE' Directory: Front End - Directory, for details. - * A mention of the language in the list of supported languages in - 'gcc/doc/install.texi'. - * A mention of the name under which the language's runtime library is - recognized by '--enable-shared=PACKAGE' in the documentation of - that option in 'gcc/doc/install.texi'. - * A mention of any special prerequisites for building the front end - in the documentation of prerequisites in 'gcc/doc/install.texi'. - * Details of contributors to that front end in - '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 - 'contrib.texi'. - * Information about support for that language in - 'gcc/doc/frontends.texi'. - * Information about standards for that language, and the front end's - support for them, in 'gcc/doc/standards.texi'. This may be a link - to such information in the front end's own manual. - * Details of source file suffixes for that language and '-x LANG' - options supported, in 'gcc/doc/invoke.texi'. - * Entries in 'default_compilers' in 'gcc.c' for source file suffixes - for that language. - * Preferably testsuites, which may be under 'gcc/testsuite' or - runtime library directories. FIXME: document somewhere how to - write testsuite harnesses. - * Probably a runtime library for the language, outside the 'gcc' - directory. FIXME: document this further. - * Details of the directories of any runtime libraries in - 'gcc/doc/sourcebuild.texi'. - * Check targets in 'Makefile.def' for the top-level 'Makefile' to - check just the compiler or the compiler and runtime library for the - language. - - If the front end is added to the official GCC source repository, the -following are also necessary: - - * At least one Bugzilla component for bugs in that front end and - runtime libraries. This category needs to be added to the Bugzilla - database. - * Normally, one or more maintainers of that front end listed in - 'MAINTAINERS'. - * Mentions on the GCC web site in 'index.html' and 'frontends.html', - with any relevant links on 'readings.html'. (Front ends that are - not an official part of GCC may also be listed on 'frontends.html', - with relevant links.) - * A news item on 'index.html', and possibly an announcement on the - <gcc-announce@gcc.gnu.org> mailing list. - * The front end's manuals should be mentioned in - 'maintainer-scripts/update_web_docs_svn' (*note Texinfo Manuals::) - and the online manuals should be linked to from - 'onlinedocs/index.html'. - * Any old releases or CVS repositories of the front end, before its - inclusion in GCC, should be made available on the GCC FTP site - <ftp://gcc.gnu.org/pub/gcc/old-releases/>. - * The release and snapshot script 'maintainer-scripts/gcc_release' - should be updated to generate appropriate tarballs for this front - end. - * If this front end includes its own version files that include the - current date, 'maintainer-scripts/update_version' should be updated - accordingly. - -* Menu: - -* Front End Directory:: The front end 'LANGUAGE' directory. -* Front End Config:: The front end 'config-lang.in' file. -* Front End Makefile:: The front end 'Make-lang.in' file. - - -File: gccint.info, Node: Front End Directory, Next: Front End Config, Up: Front End - -6.3.8.1 The Front End 'LANGUAGE' Directory -.......................................... - -A front end 'LANGUAGE' directory contains the source files of that front -end (but not of any runtime libraries, which should be outside the 'gcc' -directory). This includes documentation, and possibly some subsidiary -programs built alongside the front end. Certain files are special and -other parts of the compiler depend on their names: - -'config-lang.in' - This file is required in all language subdirectories. *Note The - Front End 'config-lang.in' File: Front End Config, for details of - its contents -'Make-lang.in' - This file is required in all language subdirectories. *Note The - Front End 'Make-lang.in' File: Front End Makefile, for details of - its contents. -'lang.opt' - This file registers the set of switches that the front end accepts - on the command line, and their '--help' text. *Note Options::. -'lang-specs.h' - This file provides entries for 'default_compilers' in 'gcc.c' which - override the default of giving an error that a compiler for that - language is not installed. -'LANGUAGE-tree.def' - This file, which need not exist, defines any language-specific tree - codes. - - -File: gccint.info, Node: Front End Config, Next: Front End Makefile, Prev: Front End Directory, Up: Front End - -6.3.8.2 The Front End 'config-lang.in' File -........................................... - -Each language subdirectory contains a 'config-lang.in' file. This file -is a shell script that may define some variables describing the -language: - -'language' - This definition must be present, and gives the name of the language - for some purposes such as arguments to '--enable-languages'. -'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 'language' settings). For example, the - Java front end depends on the C++ front end, so sets - 'lang_requires=c++'. -'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 - 'subdir_requires="cp objc"'. -'target_libs' - If defined, this variable lists (space-separated) targets in the - top level 'Makefile' to build the runtime libraries for this - language, such as 'target-libobjc'. -'lang_dirs' - If defined, this variable lists (space-separated) top level - directories (parallel to 'gcc'), apart from the runtime libraries, - that should not be configured if this front end is not built. -'build_by_default' - If defined to 'no', this language front end is not built unless - enabled in a '--enable-languages' argument. Otherwise, front ends - are built by default, subject to any special logic in - 'configure.ac' (as is present to disable the Ada front end if the - Ada compiler is not already installed). -'boot_language' - If defined to 'yes', this front end is built in stage1 of the - bootstrap. This is only relevant to front ends written in their - own languages. -'compilers' - If defined, a space-separated list of compiler executables that - will be run by the driver. The names here will each end with - '\$(exeext)'. -'outputs' - If defined, a space-separated list of files that should be - generated by 'configure' substituting values in them. This - mechanism can be used to create a file 'LANGUAGE/Makefile' from - 'LANGUAGE/Makefile.in', but this is deprecated, building everything - from the single 'gcc/Makefile' is preferred. -'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. *Note Type Information::. - - -File: gccint.info, Node: Front End Makefile, Prev: Front End Config, Up: Front End - -6.3.8.3 The Front End 'Make-lang.in' File -......................................... - -Each language subdirectory contains a 'Make-lang.in' file. It contains -targets 'LANG.HOOK' (where 'LANG' is the setting of 'language' in -'config-lang.in') for the following values of 'HOOK', and any other -Makefile rules required to build those targets (which may if necessary -use other Makefiles specified in 'outputs' in 'config-lang.in', although -this is deprecated). It also adds any testsuite targets that can use -the standard rule in 'gcc/Makefile.in' to the variable 'lang_checks'. - -'all.cross' -'start.encap' -'rest.encap' - FIXME: exactly what goes in each of these targets? -'tags' - Build an 'etags' 'TAGS' file in the language subdirectory in the - source tree. -'info' - Build info documentation for the front end, in the build directory. - This target is only called by 'make bootstrap' if a suitable - version of 'makeinfo' is available, so does not need to check for - this, and should fail if an error occurs. -'dvi' - Build DVI documentation for the front end, in the build directory. - This should be done using '$(TEXI2DVI)', with appropriate '-I' - arguments pointing to directories of included files. -'pdf' - Build PDF documentation for the front end, in the build directory. - This should be done using '$(TEXI2PDF)', with appropriate '-I' - arguments pointing to directories of included files. -'html' - Build HTML documentation for the front end, in the build directory. -'man' - Build generated man pages for the front end from Texinfo manuals - (*note 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. -'install-common' - Install everything that is part of the front end, apart from the - compiler executables listed in 'compilers' in 'config-lang.in'. -'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. -'install-man' - Install man pages for the front end. This target should ignore - errors. -'install-plugin' - Install headers needed for plugins. -'srcextra' - Copies its dependencies into the source directory. This generally - should be used for generated files such as Bison output files which - are not version-controlled, but should be included in any release - tarballs. This target will be executed during a bootstrap if - '--enable-generated-files-in-srcdir' was specified as a 'configure' - option. -'srcinfo' -'srcman' - Copies its dependencies into the source directory. These targets - will be executed during a bootstrap if - '--enable-generated-files-in-srcdir' was specified as a 'configure' - option. -'uninstall' - Uninstall files installed by installing the compiler. This is - currently documented not to be supported, so the hook need not do - anything. -'mostlyclean' -'clean' -'distclean' -'maintainer-clean' - The language parts of the standard GNU '*clean' targets. *Note - Standard Targets for Users: (standards)Standard Targets, for - details of the standard targets. For GCC, 'maintainer-clean' - should delete all generated files in the source directory that are - not version-controlled, but should not delete anything that is. - - 'Make-lang.in' must also define a variable 'LANG_OBJS' to a list of -host object files that are used by that language. - - -File: gccint.info, Node: Back End, Prev: Front End, Up: gcc Directory - -6.3.9 Anatomy of a Target Back End ----------------------------------- - -A back end for a target architecture in GCC has the following parts: - - * A directory 'MACHINE' under 'gcc/config', containing a machine - description 'MACHINE.md' file (*note Machine Descriptions: Machine - Desc.), header files 'MACHINE.h' and 'MACHINE-protos.h' and a - source file 'MACHINE.c' (*note Target Description Macros and - Functions: Target Macros.), possibly a target Makefile fragment - 't-MACHINE' (*note The Target Makefile Fragment: Target Fragment.), - and maybe some other files. The names of these files may be - changed from the defaults given by explicit specifications in - 'config.gcc'. - * If necessary, a file 'MACHINE-modes.def' in the 'MACHINE' - directory, containing additional machine modes to represent - condition codes. *Note Condition Code::, for further details. - * An optional 'MACHINE.opt' file in the 'MACHINE' directory, - containing a list of target-specific options. You can also add - other option files using the 'extra_options' variable in - 'config.gcc'. *Note Options::. - * Entries in 'config.gcc' (*note The 'config.gcc' File: System - Config.) for the systems with this target architecture. - * Documentation in 'gcc/doc/invoke.texi' for any command-line options - supported by this target (*note Run-time Target Specification: - Run-time Target.). This means both entries in the summary table of - options and details of the individual options. - * Documentation in 'gcc/doc/extend.texi' for any target-specific - attributes supported (*note Defining target-specific uses of - '__attribute__': Target Attributes.), including where the same - attribute is already supported on some targets, which are - enumerated in the manual. - * Documentation in 'gcc/doc/extend.texi' for any target-specific - pragmas supported. - * Documentation in 'gcc/doc/extend.texi' of any target-specific - built-in functions supported. - * Documentation in 'gcc/doc/extend.texi' of any target-specific - format checking styles supported. - * Documentation in 'gcc/doc/md.texi' of any target-specific - constraint letters (*note Constraints for Particular Machines: - Machine Constraints.). - * A note in 'gcc/doc/contrib.texi' under the person or people who - contributed the target support. - * Entries in '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. - * Possibly other support outside the '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. - - If the back end is added to the official GCC source repository, the -following are also necessary: - - * An entry for the target architecture in 'readings.html' on the GCC - web site, with any relevant links. - * Details of the properties of the back end and target architecture - in 'backends.html' on the GCC web site. - * A news item about the contribution of support for that target - architecture, in 'index.html' on the GCC web site. - * Normally, one or more maintainers of that target listed in - '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. - * Target triplets covering all 'config.gcc' stanzas for the target, - in the list in 'contrib/config-list.mk'. - - -File: gccint.info, Node: Testsuites, Next: Options, Prev: Source Tree, Up: Top - -7 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. -* LTO Testing:: Support for testing link-time optimizations. -* gcov Testing:: Support for testing gcov. -* profopt Testing:: Support for testing profile-directed optimizations. -* compat Testing:: Support for testing binary compatibility. -* Torture Tests:: Support for torture testing using multiple options. - - -File: gccint.info, Node: Test Idioms, Next: Test Directives, Up: Testsuites - -7.1 Idioms Used in Testsuite Code -================================= - -In general, C testcases have a trailing '-N.c', starting with '-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 '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, -'prBUG-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 '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 '-pedantic-errors'. The following idiom, where the first line -shown is line LINE of the file and the line that generates the error, is -used for this: - - /* { dg-bogus "warning" "warning in place of error" } */ - /* { dg-error "REGEXP" "MESSAGE" { target *-*-* } LINE } */ - - It may be necessary to check that an expression is an integer constant -expression and has a certain value. To check that 'E' has value 'V', an -idiom similar to the following is used: - - char x[((E) == (V) ? 1 : -1)]; - - In 'gcc.dg' tests, '__typeof__' is sometimes used to make assertions -about the types of expressions. See, for example, -'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, '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 -'gcc.c-torture/execute'. Where code should be optimized away, a call to -a nonexistent function such as 'link_failure ()' may be inserted; a -definition - - #ifndef __OPTIMIZE__ - void - link_failure (void) - { - abort (); - } - #endif - -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 'static' to call '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. - - -File: gccint.info, Node: Test Directives, Next: Ada Tests, Prev: Test Idioms, Up: Testsuites - -7.2 Directives used within DejaGnu tests -======================================== - -* Menu: - -* Directives:: Syntax and descriptions of test directives. -* Selectors:: Selecting targets to which a test applies. -* Effective-Target Keywords:: Keywords describing target attributes. -* Add Options:: Features for 'dg-add-options' -* Require Support:: Variants of 'dg-require-SUPPORT' -* Final Actions:: Commands for use in 'dg-final' - - -File: gccint.info, Node: Directives, Next: Selectors, Up: Test Directives - -7.2.1 Syntax and Descriptions of test directives ------------------------------------------------- - -Test directives appear within comments in a test source file and begin -with '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 (*note Selectors::) which are -usually preceded by the keyword 'target' or 'xfail'. - -7.2.1.1 Specify how to build the test -..................................... - -'{ dg-do DO-WHAT-KEYWORD [{ target/xfail SELECTOR }] }' - DO-WHAT-KEYWORD specifies how the test is compiled and whether it - is executed. It is one of: - - 'preprocess' - Compile with '-E' to run only the preprocessor. - 'compile' - Compile with '-S' to produce an assembly code file. - 'assemble' - Compile with '-c' to produce a relocatable object file. - 'link' - Compile, assemble, and link to produce an executable file. - 'run' - Produce and run an executable file, which is expected to - return an exit code of 0. - - The default is 'compile'. That can be overridden for a set of - tests by redefining 'dg-do-what-default' within the '.exp' file for - those tests. - - If the directive includes the optional '{ target SELECTOR }' then - the test is skipped unless the target system matches the SELECTOR. - - If DO-WHAT-KEYWORD is 'run' and the directive includes the optional - '{ xfail SELECTOR }' and the selector is met then the test is - expected to fail. The 'xfail' clause is ignored for other values - of DO-WHAT-KEYWORD; those tests can use directive 'dg-xfail-if'. - -7.2.1.2 Specify additional compiler options -........................................... - -'{ dg-options OPTIONS [{ target SELECTOR }] }' - This DejaGnu directive provides a list of compiler options, to be - used if the target system matches SELECTOR, that replace the - default options used for this set of tests. - -'{ dg-add-options FEATURE ... }' - Add any compiler options that are needed to access certain - features. This directive does nothing on targets that enable the - features by default, or that don't provide them at all. It must - come after all 'dg-options' directives. For supported values of - FEATURE see *note Add Options::. - -'{ dg-additional-options OPTIONS [{ target SELECTOR }] }' - This directive provides a list of compiler options, to be used if - the target system matches SELECTOR, that are added to the default - options used for this set of tests. - -7.2.1.3 Modify the test timeout value -..................................... - -The normal timeout limit, in seconds, is found by searching the -following in order: - - * the value defined by an earlier 'dg-timeout' directive in the test - - * variable TOOL_TIMEOUT defined by the set of tests - - * GCC,TIMEOUT set in the target board - - * 300 - -'{ dg-timeout N [{target SELECTOR }] }' - Set the time limit for the compilation and for the execution of the - test to the specified number of seconds. - -'{ dg-timeout-factor X [{ target SELECTOR }] }' - Multiply the normal time limit for compilation and execution of the - test by the specified floating-point factor. - -7.2.1.4 Skip a test for some targets -.................................... - -'{ dg-skip-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' - Arguments INCLUDE-OPTS and EXCLUDE-OPTS are lists in which each - element is a string of zero or more GCC options. Skip the test if - all of the following conditions are met: - * the test system is included in SELECTOR - - * for at least one of the option strings in INCLUDE-OPTS, every - option from that string is in the set of options with which - the test would be compiled; use '"*"' for an INCLUDE-OPTS list - that matches any options; that is the default if INCLUDE-OPTS - is not specified - - * for each of the option strings in EXCLUDE-OPTS, at least one - option from that string is not in the set of options with - which the test would be compiled; use '""' for an empty - EXCLUDE-OPTS list; that is the default if EXCLUDE-OPTS is not - specified - - For example, to skip a test if option '-Os' is present: - - /* { dg-skip-if "" { *-*-* } { "-Os" } { "" } } */ - - To skip a test if both options '-O2' and '-g' are present: - - /* { dg-skip-if "" { *-*-* } { "-O2 -g" } { "" } } */ - - To skip a test if either '-O2' or '-O3' is present: - - /* { dg-skip-if "" { *-*-* } { "-O2" "-O3" } { "" } } */ - - To skip a test unless option '-Os' is present: - - /* { dg-skip-if "" { *-*-* } { "*" } { "-Os" } } */ - - To skip a test if either '-O2' or '-O3' is used with '-g' but not - if '-fpic' is also present: - - /* { dg-skip-if "" { *-*-* } { "-O2 -g" "-O3 -g" } { "-fpic" } } */ - -'{ dg-require-effective-target KEYWORD [{ SELECTOR }] }' - Skip the test if the test target, including current multilib flags, - is not covered by the effective-target keyword. If the directive - includes the optional '{ SELECTOR }' then the effective-target test - is only performed if the target system matches the SELECTOR. This - directive must appear after any 'dg-do' directive in the test and - before any 'dg-additional-sources' directive. *Note - Effective-Target Keywords::. - -'{ dg-require-SUPPORT args }' - Skip the test if the target does not provide the required support. - These directives must appear after any 'dg-do' directive in the - test and before any 'dg-additional-sources' directive. They - require at least one argument, which can be an empty string if the - specific procedure does not examine the argument. *Note Require - Support::, for a complete list of these directives. - -7.2.1.5 Expect a test to fail for some targets -.............................................. - -'{ dg-xfail-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' - Expect the test to fail if the conditions (which are the same as - for 'dg-skip-if') are met. This does not affect the execute step. - -'{ dg-xfail-run-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' - Expect the execute step of a test to fail if the conditions (which - are the same as for 'dg-skip-if') are met. - -7.2.1.6 Expect the test executable to fail -.......................................... - -'{ dg-shouldfail COMMENT [{ SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]]] }' - Expect the test executable to return a nonzero exit status if the - conditions (which are the same as for 'dg-skip-if') are met. - -7.2.1.7 Verify compiler messages -................................ - -'{ dg-error REGEXP [COMMENT [{ target/xfail SELECTOR } [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 REGEXP then the check fails - and COMMENT is included in the 'FAIL' message. The check does not - look for the string 'error' unless it is part of REGEXP. - -'{ dg-warning REGEXP [COMMENT [{ target/xfail SELECTOR } [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 REGEXP then the check fails - and COMMENT is included in the 'FAIL' message. The check does not - look for the string 'warning' unless it is part of REGEXP. - -'{ dg-message REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' - The line is expected to get a message other than an error or - warning. If there is no message for that line or if the text of - that message is not matched by REGEXP then the check fails and - COMMENT is included in the 'FAIL' message. - -'{ dg-bogus REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' - This DejaGnu directive appears on a source line that should not get - a message matching REGEXP, or else specifies the source line - associated with the bogus message. It is usually used with 'xfail' - to indicate that the message is a known problem for a particular - set of targets. - -'{ dg-excess-errors COMMENT [{ target/xfail SELECTOR }] }' - This DejaGnu directive indicates that the test is expected to fail - due to compiler messages that are not handled by 'dg-error', - 'dg-warning' or 'dg-bogus'. For this directive 'xfail' has the - same effect as 'target'. - -'{ dg-prune-output REGEXP }' - Prune messages matching REGEXP from the test output. - -7.2.1.8 Verify output of the test executable -............................................ - -'{ dg-output REGEXP [{ target/xfail SELECTOR }] }' - This DejaGnu directive compares REGEXP to the combined output that - the test executable writes to 'stdout' and 'stderr'. - -7.2.1.9 Specify additional files for a test -........................................... - -'{ dg-additional-files "FILELIST" }' - Specify additional files, other than source files, that must be - copied to the system where the compiler runs. - -'{ dg-additional-sources "FILELIST" }' - Specify additional source files to appear in the compile line - following the main test file. - -7.2.1.10 Add checks at the end of a test -........................................ - -'{ dg-final { 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 'dg-final' commands are processed in the order in - which they appear in the source file. *Note Final Actions::, for a - list of directives that can be used within 'dg-final'. - - -File: gccint.info, Node: Selectors, Next: Effective-Target Keywords, Prev: Directives, Up: Test Directives - -7.2.2 Selecting targets to which a test applies ------------------------------------------------ - -Several test directives include SELECTORs to limit the targets for which -a test is run or to declare that a test is expected to fail on -particular targets. - - A selector is: - * one or more target triplets, possibly including wildcard - characters; use '*-*-*' to match any target - * a single effective-target keyword (*note Effective-Target - Keywords::) - * a logical expression - - Depending on the context, the selector specifies whether a test is -skipped and reported as unsupported or is expected to fail. A context -that allows either 'target' or 'xfail' also allows '{ target SELECTOR1 -xfail SELECTOR2 }' to skip the test for targets that don't match -SELECTOR1 and the test to fail for targets that match SELECTOR2. - - A selector expression appears within curly braces and uses a single -logical operator: one of '!', '&&', or '||'. 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: - - { target { ! "hppa*-*-* ia64*-*-*" } } - { target { powerpc*-*-* && lp64 } } - { xfail { lp64 || vect_no_align } } - - -File: gccint.info, Node: Effective-Target Keywords, Next: Add Options, Prev: Selectors, Up: Test Directives - -7.2.3 Keywords describing target attributes -------------------------------------------- - -Effective-target keywords identify sets of targets that support -particular functionality. They are used to limit tests to be run only -for particular targets, or to specify that particular sets of targets -are expected to fail some tests. - - Effective-target keywords are defined in 'lib/target-supports.exp' in -the GCC testsuite, with the exception of those that are documented as -being local to a particular test directory. - - The 'effective target' takes into account all of the compiler options -with which the test will be compiled, including the multilib options. -By convention, keywords ending in '_nocache' can also include options -specified for the particular test in an earlier 'dg-options' or -'dg-add-options' directive. - -7.2.3.1 Data type sizes -....................... - -'ilp32' - Target has 32-bit 'int', 'long', and pointers. - -'lp64' - Target has 32-bit 'int', 64-bit 'long' and pointers. - -'llp64' - Target has 32-bit 'int' and 'long', 64-bit 'long long' and - pointers. - -'double64' - Target has 64-bit 'double'. - -'double64plus' - Target has 'double' that is 64 bits or longer. - -'int32plus' - Target has 'int' that is at 32 bits or longer. - -'int16' - Target has 'int' that is 16 bits or shorter. - -'long_neq_int' - Target has 'int' and 'long' with different sizes. - -'large_double' - Target supports 'double' that is longer than 'float'. - -'large_long_double' - Target supports 'long double' that is longer than 'double'. - -'ptr32plus' - Target has pointers that are 32 bits or longer. - -'size32plus' - Target supports array and structure sizes that are 32 bits or - longer. - -'4byte_wchar_t' - Target has 'wchar_t' that is at least 4 bytes. - -7.2.3.2 Fortran-specific attributes -................................... - -'fortran_integer_16' - Target supports Fortran 'integer' that is 16 bytes or longer. - -'fortran_large_int' - Target supports Fortran 'integer' kinds larger than 'integer(8)'. - -'fortran_large_real' - Target supports Fortran 'real' kinds larger than 'real(8)'. - -7.2.3.3 Vector-specific attributes -.................................. - -'vect_condition' - Target supports vector conditional operations. - -'vect_double' - Target supports hardware vectors of 'double'. - -'vect_float' - Target supports hardware vectors of 'float'. - -'vect_int' - Target supports hardware vectors of 'int'. - -'vect_long' - Target supports hardware vectors of 'long'. - -'vect_long_long' - Target supports hardware vectors of 'long long'. - -'vect_aligned_arrays' - Target aligns arrays to vector alignment boundary. - -'vect_hw_misalign' - Target supports a vector misalign access. - -'vect_no_align' - Target does not support a vector alignment mechanism. - -'vect_no_int_max' - Target does not support a vector max instruction on 'int'. - -'vect_no_int_add' - Target does not support a vector add instruction on 'int'. - -'vect_no_bitwise' - Target does not support vector bitwise instructions. - -'vect_char_mult' - Target supports 'vector char' multiplication. - -'vect_short_mult' - Target supports 'vector short' multiplication. - -'vect_int_mult' - Target supports 'vector int' multiplication. - -'vect_extract_even_odd' - Target supports vector even/odd element extraction. - -'vect_extract_even_odd_wide' - Target supports vector even/odd element extraction of vectors with - elements 'SImode' or larger. - -'vect_interleave' - Target supports vector interleaving. - -'vect_strided' - Target supports vector interleaving and extract even/odd. - -'vect_strided_wide' - Target supports vector interleaving and extract even/odd for wide - element types. - -'vect_perm' - Target supports vector permutation. - -'vect_shift' - Target supports a hardware vector shift operation. - -'vect_widen_sum_hi_to_si' - Target supports a vector widening summation of 'short' operands - into 'int' results, or can promote (unpack) from 'short' to 'int'. - -'vect_widen_sum_qi_to_hi' - Target supports a vector widening summation of 'char' operands into - 'short' results, or can promote (unpack) from 'char' to 'short'. - -'vect_widen_sum_qi_to_si' - Target supports a vector widening summation of 'char' operands into - 'int' results. - -'vect_widen_mult_qi_to_hi' - Target supports a vector widening multiplication of 'char' operands - into 'short' results, or can promote (unpack) from 'char' to - 'short' and perform non-widening multiplication of 'short'. - -'vect_widen_mult_hi_to_si' - Target supports a vector widening multiplication of 'short' - operands into 'int' results, or can promote (unpack) from 'short' - to 'int' and perform non-widening multiplication of 'int'. - -'vect_widen_mult_si_to_di_pattern' - Target supports a vector widening multiplication of 'int' operands - into 'long' results. - -'vect_sdot_qi' - Target supports a vector dot-product of 'signed char'. - -'vect_udot_qi' - Target supports a vector dot-product of 'unsigned char'. - -'vect_sdot_hi' - Target supports a vector dot-product of 'signed short'. - -'vect_udot_hi' - Target supports a vector dot-product of 'unsigned short'. - -'vect_pack_trunc' - Target supports a vector demotion (packing) of 'short' to 'char' - and from 'int' to 'short' using modulo arithmetic. - -'vect_unpack' - Target supports a vector promotion (unpacking) of 'char' to 'short' - and from 'char' to 'int'. - -'vect_intfloat_cvt' - Target supports conversion from 'signed int' to 'float'. - -'vect_uintfloat_cvt' - Target supports conversion from 'unsigned int' to 'float'. - -'vect_floatint_cvt' - Target supports conversion from 'float' to 'signed int'. - -'vect_floatuint_cvt' - Target supports conversion from 'float' to 'unsigned int'. - -7.2.3.4 Thread Local Storage attributes -....................................... - -'tls' - Target supports thread-local storage. - -'tls_native' - Target supports native (rather than emulated) thread-local storage. - -'tls_runtime' - Test system supports executing TLS executables. - -7.2.3.5 Decimal floating point attributes -......................................... - -'dfp' - Targets supports compiling decimal floating point extension to C. - -'dfp_nocache' - Including the options used to compile this particular test, the - target supports compiling decimal floating point extension to C. - -'dfprt' - Test system can execute decimal floating point tests. - -'dfprt_nocache' - Including the options used to compile this particular test, the - test system can execute decimal floating point tests. - -'hard_dfp' - Target generates decimal floating point instructions with current - options. - -7.2.3.6 ARM-specific attributes -............................... - -'arm32' - ARM target generates 32-bit code. - -'arm_eabi' - ARM target adheres to the ABI for the ARM Architecture. - -'arm_hf_eabi' - ARM target adheres to the VFP and Advanced SIMD Register Arguments - variant of the ABI for the ARM Architecture (as selected with - '-mfloat-abi=hard'). - -'arm_hard_vfp_ok' - ARM target supports '-mfpu=vfp -mfloat-abi=hard'. Some multilibs - may be incompatible with these options. - -'arm_iwmmxt_ok' - ARM target supports '-mcpu=iwmmxt'. Some multilibs may be - incompatible with this option. - -'arm_neon' - ARM target supports generating NEON instructions. - -'arm_neon_hw' - Test system supports executing NEON instructions. - -'arm_neonv2_hw' - Test system supports executing NEON v2 instructions. - -'arm_neon_ok' - ARM Target supports '-mfpu=neon -mfloat-abi=softfp' or compatible - options. Some multilibs may be incompatible with these options. - -'arm_neonv2_ok' - ARM Target supports '-mfpu=neon-vfpv4 -mfloat-abi=softfp' or - compatible options. Some multilibs may be incompatible with these - options. - -'arm_neon_fp16_ok' - ARM Target supports '-mfpu=neon-fp16 -mfloat-abi=softfp' or - compatible options. Some multilibs may be incompatible with these - options. - -'arm_thumb1_ok' - ARM target generates Thumb-1 code for '-mthumb'. - -'arm_thumb2_ok' - ARM target generates Thumb-2 code for '-mthumb'. - -'arm_vfp_ok' - ARM target supports '-mfpu=vfp -mfloat-abi=softfp'. Some multilibs - may be incompatible with these options. - -'arm_vfp3_ok' - ARM target supports '-mfpu=vfp3 -mfloat-abi=softfp'. Some - multilibs may be incompatible with these options. - -'arm_v8_vfp_ok' - ARM target supports '-mfpu=fp-armv8 -mfloat-abi=softfp'. Some - multilibs may be incompatible with these options. - -'arm_v8_neon_ok' - ARM target supports '-mfpu=neon-fp-armv8 -mfloat-abi=softfp'. Some - multilibs may be incompatible with these options. - -'arm_prefer_ldrd_strd' - ARM target prefers 'LDRD' and 'STRD' instructions over 'LDM' and - 'STM' instructions. - -7.2.3.7 MIPS-specific attributes -................................ - -'mips64' - MIPS target supports 64-bit instructions. - -'nomips16' - MIPS target does not produce MIPS16 code. - -'mips16_attribute' - MIPS target can generate MIPS16 code. - -'mips_loongson' - MIPS target is a Loongson-2E or -2F target using an ABI that - supports the Loongson vector modes. - -'mips_newabi_large_long_double' - MIPS target supports 'long double' larger than 'double' when using - the new ABI. - -'mpaired_single' - MIPS target supports '-mpaired-single'. - -7.2.3.8 PowerPC-specific attributes -................................... - -'powerpc64' - Test system supports executing 64-bit instructions. - -'powerpc_altivec' - PowerPC target supports AltiVec. - -'powerpc_altivec_ok' - PowerPC target supports '-maltivec'. - -'powerpc_fprs' - PowerPC target supports floating-point registers. - -'powerpc_hard_double' - PowerPC target supports hardware double-precision floating-point. - -'powerpc_ppu_ok' - PowerPC target supports '-mcpu=cell'. - -'powerpc_spe' - PowerPC target supports PowerPC SPE. - -'powerpc_spe_nocache' - Including the options used to compile this particular test, the - PowerPC target supports PowerPC SPE. - -'powerpc_spu' - PowerPC target supports PowerPC SPU. - -'spu_auto_overlay' - SPU target has toolchain that supports automatic overlay - generation. - -'powerpc_vsx_ok' - PowerPC target supports '-mvsx'. - -'powerpc_405_nocache' - Including the options used to compile this particular test, the - PowerPC target supports PowerPC 405. - -'vmx_hw' - PowerPC target supports executing AltiVec instructions. - -7.2.3.9 Other hardware attributes -................................. - -'avx' - Target supports compiling 'avx' instructions. - -'avx_runtime' - Target supports the execution of 'avx' instructions. - -'cell_hw' - Test system can execute AltiVec and Cell PPU instructions. - -'coldfire_fpu' - Target uses a ColdFire FPU. - -'hard_float' - Target supports FPU instructions. - -'sse' - Target supports compiling 'sse' instructions. - -'sse_runtime' - Target supports the execution of 'sse' instructions. - -'sse2' - Target supports compiling 'sse2' instructions. - -'sse2_runtime' - Target supports the execution of 'sse2' instructions. - -'sync_char_short' - Target supports atomic operations on 'char' and 'short'. - -'sync_int_long' - Target supports atomic operations on 'int' and 'long'. - -'ultrasparc_hw' - Test environment appears to run executables on a simulator that - accepts only 'EM_SPARC' executables and chokes on 'EM_SPARC32PLUS' - or 'EM_SPARCV9' executables. - -'vect_cmdline_needed' - Target requires a command line argument to enable a SIMD - instruction set. - -7.2.3.10 Environment attributes -............................... - -'c' - The language for the compiler under test is C. - -'c++' - The language for the compiler under test is C++. - -'c99_runtime' - Target provides a full C99 runtime. - -'correct_iso_cpp_string_wchar_protos' - Target 'string.h' and 'wchar.h' headers provide C++ required - overloads for 'strchr' etc. functions. - -'dummy_wcsftime' - Target uses a dummy 'wcsftime' function that always returns zero. - -'fd_truncate' - Target can truncate a file from a file descriptor, as used by - 'libgfortran/io/unix.c:fd_truncate'; i.e. 'ftruncate' or 'chsize'. - -'freestanding' - Target is 'freestanding' as defined in section 4 of the C99 - standard. Effectively, it is a target which supports no extra - headers or libraries other than what is considered essential. - -'init_priority' - Target supports constructors with initialization priority - arguments. - -'inttypes_types' - Target has the basic signed and unsigned types in 'inttypes.h'. - This is for tests that GCC's notions of these types agree with - those in the header, as some systems have only 'inttypes.h'. - -'lax_strtofp' - Target might have errors of a few ULP in string to floating-point - conversion functions and overflow is not always detected correctly - by those functions. - -'mmap' - Target supports 'mmap'. - -'newlib' - Target supports Newlib. - -'pow10' - Target provides 'pow10' function. - -'pthread' - Target can compile using 'pthread.h' with no errors or warnings. - -'pthread_h' - Target has 'pthread.h'. - -'run_expensive_tests' - Expensive testcases (usually those that consume excessive amounts - of CPU time) should be run on this target. This can be enabled by - setting the 'GCC_TEST_RUN_EXPENSIVE' environment variable to a - non-empty string. - -'simulator' - Test system runs executables on a simulator (i.e. slowly) rather - than hardware (i.e. fast). - -'stdint_types' - Target has the basic signed and unsigned C types in 'stdint.h'. - This will be obsolete when GCC ensures a working 'stdint.h' for all - targets. - -'trampolines' - Target supports trampolines. - -'uclibc' - Target supports uClibc. - -'unwrapped' - Target does not use a status wrapper. - -'vxworks_kernel' - Target is a VxWorks kernel. - -'vxworks_rtp' - Target is a VxWorks RTP. - -'wchar' - Target supports wide characters. - -7.2.3.11 Other attributes -......................... - -'automatic_stack_alignment' - Target supports automatic stack alignment. - -'cxa_atexit' - Target uses '__cxa_atexit'. - -'default_packed' - Target has packed layout of structure members by default. - -'fgraphite' - Target supports Graphite optimizations. - -'fixed_point' - Target supports fixed-point extension to C. - -'fopenmp' - Target supports OpenMP via '-fopenmp'. - -'fpic' - Target supports '-fpic' and '-fPIC'. - -'freorder' - Target supports '-freorder-blocks-and-partition'. - -'fstack_protector' - Target supports '-fstack-protector'. - -'gas' - Target uses GNU 'as'. - -'gc_sections' - Target supports '--gc-sections'. - -'gld' - Target uses GNU 'ld'. - -'keeps_null_pointer_checks' - Target keeps null pointer checks, either due to the use of - '-fno-delete-null-pointer-checks' or hardwired into the target. - -'lto' - Compiler has been configured to support link-time optimization - (LTO). - -'naked_functions' - Target supports the 'naked' function attribute. - -'named_sections' - Target supports named sections. - -'natural_alignment_32' - Target uses natural alignment (aligned to type size) for types of - 32 bits or less. - -'target_natural_alignment_64' - Target uses natural alignment (aligned to type size) for types of - 64 bits or less. - -'nonpic' - Target does not generate PIC by default. - -'pcc_bitfield_type_matters' - Target defines 'PCC_BITFIELD_TYPE_MATTERS'. - -'pe_aligned_commons' - Target supports '-mpe-aligned-commons'. - -'pie' - Target supports '-pie', '-fpie' and '-fPIE'. - -'section_anchors' - Target supports section anchors. - -'short_enums' - Target defaults to short enums. - -'static' - Target supports '-static'. - -'static_libgfortran' - Target supports statically linking 'libgfortran'. - -'string_merging' - Target supports merging string constants at link time. - -'ucn' - Target supports compiling and assembling UCN. - -'ucn_nocache' - Including the options used to compile this particular test, the - target supports compiling and assembling UCN. - -'unaligned_stack' - Target does not guarantee that its 'STACK_BOUNDARY' is greater than - or equal to the required vector alignment. - -'vector_alignment_reachable' - Vector alignment is reachable for types of 32 bits or less. - -'vector_alignment_reachable_for_64bit' - Vector alignment is reachable for types of 64 bits or less. - -'wchar_t_char16_t_compatible' - Target supports 'wchar_t' that is compatible with 'char16_t'. - -'wchar_t_char32_t_compatible' - Target supports 'wchar_t' that is compatible with 'char32_t'. - -7.2.3.12 Local to tests in 'gcc.target/i386' -............................................ - -'3dnow' - Target supports compiling '3dnow' instructions. - -'aes' - Target supports compiling 'aes' instructions. - -'fma4' - Target supports compiling 'fma4' instructions. - -'ms_hook_prologue' - Target supports attribute 'ms_hook_prologue'. - -'pclmul' - Target supports compiling 'pclmul' instructions. - -'sse3' - Target supports compiling 'sse3' instructions. - -'sse4' - Target supports compiling 'sse4' instructions. - -'sse4a' - Target supports compiling 'sse4a' instructions. - -'ssse3' - Target supports compiling 'ssse3' instructions. - -'vaes' - Target supports compiling 'vaes' instructions. - -'vpclmul' - Target supports compiling 'vpclmul' instructions. - -'xop' - Target supports compiling 'xop' instructions. - -7.2.3.13 Local to tests in 'gcc.target/spu/ea' -.............................................. - -'ealib' - Target '__ea' library functions are available. - -7.2.3.14 Local to tests in 'gcc.test-framework' -............................................... - -'no' - Always returns 0. - -'yes' - Always returns 1. - - -File: gccint.info, Node: Add Options, Next: Require Support, Prev: Effective-Target Keywords, Up: Test Directives - -7.2.4 Features for 'dg-add-options' ------------------------------------ - -The supported values of FEATURE for directive 'dg-add-options' are: - -'arm_neon' - NEON support. Only ARM targets support this feature, and only then - in certain modes; see the *note arm_neon_ok effective target - keyword: arm_neon_ok. - -'arm_neon_fp16' - NEON and half-precision floating point support. Only ARM targets - support this feature, and only then in certain modes; see the *note - arm_neon_fp16_ok effective target keyword: arm_neon_ok. - -'arm_vfp3' - arm vfp3 floating point support; see the *note arm_vfp3_ok - effective target keyword: arm_vfp3_ok. - -'bind_pic_locally' - Add the target-specific flags needed to enable functions to bind - locally when using pic/PIC passes in the testsuite. - -'c99_runtime' - Add the target-specific flags needed to access the C99 runtime. - -'ieee' - Add the target-specific flags needed to enable full IEEE compliance - mode. - -'mips16_attribute' - 'mips16' function attributes. Only MIPS targets support this - feature, and only then in certain modes. - -'tls' - Add the target-specific flags needed to use thread-local storage. - - -File: gccint.info, Node: Require Support, Next: Final Actions, Prev: Add Options, Up: Test Directives - -7.2.5 Variants of 'dg-require-SUPPORT' --------------------------------------- - -A few of the 'dg-require' directives take arguments. - -'dg-require-iconv CODESET' - Skip the test if the target does not support iconv. CODESET is the - codeset to convert to. - -'dg-require-profiling PROFOPT' - Skip the test if the target does not support profiling with option - PROFOPT. - -'dg-require-visibility VIS' - Skip the test if the target does not support the 'visibility' - attribute. If VIS is '""', support for 'visibility("hidden")' is - checked, for 'visibility("VIS")' otherwise. - - The original 'dg-require' directives were defined before there was -support for effective-target keywords. The directives that do not take -arguments could be replaced with effective-target keywords. - -'dg-require-alias ""' - Skip the test if the target does not support the 'alias' attribute. - -'dg-require-ascii-locale ""' - Skip the test if the host does not support an ASCII locale. - -'dg-require-compat-dfp ""' - Skip this test unless both compilers in a 'compat' testsuite - support decimal floating point. - -'dg-require-cxa-atexit ""' - Skip the test if the target does not support '__cxa_atexit'. This - is equivalent to 'dg-require-effective-target cxa_atexit'. - -'dg-require-dll ""' - Skip the test if the target does not support DLL attributes. - -'dg-require-fork ""' - Skip the test if the target does not support 'fork'. - -'dg-require-gc-sections ""' - Skip the test if the target's linker does not support the - '--gc-sections' flags. This is equivalent to - 'dg-require-effective-target gc-sections'. - -'dg-require-host-local ""' - Skip the test if the host is remote, rather than the same as the - build system. Some tests are incompatible with DejaGnu's handling - of remote hosts, which involves copying the source file to the host - and compiling it with a relative path and "'-o a.out'". - -'dg-require-mkfifo ""' - Skip the test if the target does not support 'mkfifo'. - -'dg-require-named-sections ""' - Skip the test is the target does not support named sections. This - is equivalent to 'dg-require-effective-target named_sections'. - -'dg-require-weak ""' - Skip the test if the target does not support weak symbols. - -'dg-require-weak-override ""' - Skip the test if the target does not support overriding weak - symbols. - - -File: gccint.info, Node: Final Actions, Prev: Require Support, Up: Test Directives - -7.2.6 Commands for use in 'dg-final' ------------------------------------- - -The GCC testsuite defines the following directives to be used within -'dg-final'. - -7.2.6.1 Scan a particular file -.............................. - -'scan-file FILENAME REGEXP [{ target/xfail SELECTOR }]' - Passes if REGEXP matches text in FILENAME. -'scan-file-not FILENAME REGEXP [{ target/xfail SELECTOR }]' - Passes if REGEXP does not match text in FILENAME. -'scan-module MODULE REGEXP [{ target/xfail SELECTOR }]' - Passes if REGEXP matches in Fortran module MODULE. - -7.2.6.2 Scan the assembly output -................................ - -'scan-assembler REGEX [{ target/xfail SELECTOR }]' - Passes if REGEX matches text in the test's assembler output. - -'scan-assembler-not REGEX [{ target/xfail SELECTOR }]' - Passes if REGEX does not match text in the test's assembler output. - -'scan-assembler-times REGEX NUM [{ target/xfail SELECTOR }]' - Passes if REGEX is matched exactly NUM times in the test's - assembler output. - -'scan-assembler-dem REGEX [{ target/xfail SELECTOR }]' - Passes if REGEX matches text in the test's demangled assembler - output. - -'scan-assembler-dem-not REGEX [{ target/xfail SELECTOR }]' - Passes if REGEX does not match text in the test's demangled - assembler output. - -'scan-hidden SYMBOL [{ target/xfail SELECTOR }]' - Passes if SYMBOL is defined as a hidden symbol in the test's - assembly output. - -'scan-not-hidden SYMBOL [{ target/xfail SELECTOR }]' - Passes if SYMBOL is not defined as a hidden symbol in the test's - assembly output. - -7.2.6.3 Scan optimization dump files -.................................... - -These commands are available for KIND of 'tree', 'rtl', and 'ipa'. - -'scan-KIND-dump REGEX SUFFIX [{ target/xfail SELECTOR }]' - Passes if REGEX matches text in the dump file with suffix SUFFIX. - -'scan-KIND-dump-not REGEX SUFFIX [{ target/xfail SELECTOR }]' - Passes if REGEX does not match text in the dump file with suffix - SUFFIX. - -'scan-KIND-dump-times REGEX NUM SUFFIX [{ target/xfail SELECTOR }]' - Passes if REGEX is found exactly NUM times in the dump file with - suffix SUFFIX. - -'scan-KIND-dump-dem REGEX SUFFIX [{ target/xfail SELECTOR }]' - Passes if REGEX matches demangled text in the dump file with suffix - SUFFIX. - -'scan-KIND-dump-dem-not REGEX SUFFIX [{ target/xfail SELECTOR }]' - Passes if REGEX does not match demangled text in the dump file with - suffix SUFFIX. - -7.2.6.4 Verify that an output files exists or not -................................................. - -'output-exists [{ target/xfail SELECTOR }]' - Passes if compiler output file exists. - -'output-exists-not [{ target/xfail SELECTOR }]' - Passes if compiler output file does not exist. - -7.2.6.5 Check for LTO tests -........................... - -'scan-symbol REGEXP [{ target/xfail SELECTOR }]' - Passes if the pattern is present in the final executable. - -7.2.6.6 Checks for 'gcov' tests -............................... - -'run-gcov SOURCEFILE' - Check line counts in 'gcov' tests. - -'run-gcov [branches] [calls] { OPTS SOURCEFILE }' - Check branch and/or call counts, in addition to line counts, in - 'gcov' tests. - -7.2.6.7 Clean up generated test files -..................................... - -'cleanup-coverage-files' - Removes coverage data files generated for this test. - -'cleanup-ipa-dump SUFFIX' - Removes IPA dump files generated for this test. - -'cleanup-modules "LIST-OF-EXTRA-MODULES"' - Removes Fortran module files generated for this test, excluding the - module names listed in keep-modules. Cleaning up module files is - usually done automatically by the testsuite by looking at the - source files and removing the modules after the test has been - executed. - module MoD1 - end module MoD1 - module Mod2 - end module Mod2 - module moD3 - end module moD3 - module mod4 - end module mod4 - ! { dg-final { cleanup-modules "mod1 mod2" } } ! redundant - ! { dg-final { keep-modules "mod3 mod4" } } - -'keep-modules "LIST-OF-MODULES-NOT-TO-DELETE"' - Whitespace separated list of module names that should not be - deleted by cleanup-modules. If the list of modules is empty, all - modules defined in this file are kept. - module maybe_unneeded - end module maybe_unneeded - module keep1 - end module keep1 - module keep2 - end module keep2 - ! { dg-final { keep-modules "keep1 keep2" } } ! just keep these two - ! { dg-final { keep-modules "" } } ! keep all - -'cleanup-profile-file' - Removes profiling files generated for this test. - -'cleanup-repo-files' - Removes files generated for this test for '-frepo'. - -'cleanup-rtl-dump SUFFIX' - Removes RTL dump files generated for this test. - -'cleanup-saved-temps' - Removes files for the current test which were kept for - '-save-temps'. - -'cleanup-tree-dump SUFFIX' - Removes tree dump files matching SUFFIX which were generated for - this test. - - -File: gccint.info, Node: Ada Tests, Next: C Tests, Prev: Test Directives, Up: Testsuites - -7.3 Ada Language Testsuites -=========================== - -The Ada testsuite includes executable tests from the ACATS testsuite, -publicly available at <http://www.ada-auth.org/acats.html>. - - These tests are integrated in the GCC testsuite in the 'ada/acats' -directory, and enabled automatically when running 'make check', assuming -the Ada language has been enabled when configuring GCC. - - You can also run the Ada testsuite independently, using 'make -check-ada', or run a subset of the tests by specifying which chapter to -run, e.g.: - - $ make check-ada CHAPTERS="c3 c9" - - 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 'gcc' containing a template for -creating new executable tests, although this is deprecated in favor of -the 'gnat.dg' testsuite. - - The tests are run using two 'sh' scripts: 'run_acats' and 'run_all.sh'. -To run the tests using a simulator or a cross target, see the small -customization section at the top of 'run_all.sh'. - - These tests are run using the build tree: they can be run without doing -a 'make install'. - - -File: gccint.info, Node: C Tests, Next: libgcj Tests, Prev: Ada Tests, Up: Testsuites - -7.4 C Language Testsuites -========================= - -GCC contains the following C language testsuites, in the 'gcc/testsuite' -directory: - -'gcc.dg' - This contains tests of particular features of the C compiler, using - the more modern '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 '-ansi - -pedantic' unless other options are given in the test. Except as - noted below they are not run with multiple optimization options. -'gcc.dg/compat' - This subdirectory contains tests for binary compatibility using - 'lib/compat.exp', which in turn uses the language-independent - support (*note Support for testing binary compatibility: compat - Testing.). -'gcc.dg/cpp' - This subdirectory contains tests of the preprocessor. -'gcc.dg/debug' - This subdirectory contains tests for debug formats. Tests in this - subdirectory are run for each debug format that the compiler - supports. -'gcc.dg/format' - This subdirectory contains tests of the '-Wformat' format checking. - Tests in this directory are run with and without '-DWIDE'. -'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. -'gcc.dg/special' - FIXME: describe this. - -'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. - -'gcc.c-torture/compat' - FIXME: describe this. - - This directory should probably not be used for new tests. -'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 '.x' files, mostly these test cases should - not contain platform dependencies. FIXME: discuss how defines such - as 'NO_LABEL_VALUES' and 'STACK_SIZE' are used. -'gcc.c-torture/execute' - This testsuite contains test cases that should compile, link and - run; otherwise the same comments as for 'gcc.c-torture/compile' - apply. -'gcc.c-torture/execute/ieee' - This contains tests which are specific to IEEE floating point. -'gcc.c-torture/unsorted' - FIXME: describe this. - - This directory should probably not be used for new tests. -'gcc.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: - - 'bprob*.c' - Test '-fbranch-probabilities' using - 'gcc.misc-tests/bprob.exp', which in turn uses the generic, - language-independent framework (*note Support for testing - profile-directed optimizations: profopt Testing.). - - 'gcov*.c' - Test 'gcov' output using 'gcov.exp', which in turn uses the - language-independent support (*note Support for testing gcov: - gcov Testing.). - - 'i386-pf-*.c' - Test i386-specific support for data prefetch using - 'i386-prefetch.exp'. - -'gcc.test-framework' - 'dg-*.c' - Test the testsuite itself using - 'gcc.test-framework/test-framework.exp'. - - FIXME: merge in 'testsuite/README.gcc' and discuss the format of test -cases and magic comments more. - - -File: gccint.info, Node: libgcj Tests, Next: LTO Testing, Prev: C Tests, Up: Testsuites - -7.5 The Java library testsuites. -================================ - -Runtime tests are executed via 'make check' in the -'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 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 -'libjava/testsuite/libjava.mauve/mauve', or by specifying the location -of that tree when invoking 'make', as in 'make MAUVEDIR=~/mauve check'. - - To detect regressions, a mechanism in 'mauve.exp' compares the failures -for a test run against the list of expected failures in -'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. - - We encourage developers to contribute test cases to Mauve. - - -File: gccint.info, Node: LTO Testing, Next: gcov Testing, Prev: libgcj Tests, Up: Testsuites - -7.6 Support for testing link-time optimizations -=============================================== - -Tests for link-time optimizations usually require multiple source files -that are compiled separately, perhaps with different sets of options. -There are several special-purpose test directives used for these tests. - -'{ dg-lto-do DO-WHAT-KEYWORD }' - DO-WHAT-KEYWORD specifies how the test is compiled and whether it - is executed. It is one of: - - 'assemble' - Compile with '-c' to produce a relocatable object file. - 'link' - Compile, assemble, and link to produce an executable file. - 'run' - Produce and run an executable file, which is expected to - return an exit code of 0. - - The default is 'assemble'. That can be overridden for a set of - tests by redefining 'dg-do-what-default' within the '.exp' file for - those tests. - - Unlike 'dg-do', 'dg-lto-do' does not support an optional 'target' - or 'xfail' list. Use 'dg-skip-if', 'dg-xfail-if', or - 'dg-xfail-run-if'. - -'{ dg-lto-options { { OPTIONS } [{ OPTIONS }] } [{ target SELECTOR }]}' - This directive provides a list of one or more sets of compiler - options to override LTO_OPTIONS. Each test will be compiled and - run with each of these sets of options. - -'{ dg-extra-ld-options OPTIONS [{ target SELECTOR }]}' - This directive adds OPTIONS to the linker options used. - -'{ dg-suppress-ld-options OPTIONS [{ target SELECTOR }]}' - This directive removes OPTIONS from the set of linker options used. - - -File: gccint.info, Node: gcov Testing, Next: profopt Testing, Prev: LTO Testing, Up: Testsuites - -7.7 Support for testing 'gcov' -============================== - -Language-independent support for testing 'gcov', and for checking that -branch profiling produces expected values, is provided by the expect -file 'lib/gcov.exp'. 'gcov' tests also rely on procedures in -'lib/gcc-dg.exp' to compile and run the test program. A typical 'gcov' -test contains the following DejaGnu commands within comments: - - { dg-options "-fprofile-arcs -ftest-coverage" } - { dg-do run { target native } } - { dg-final { run-gcov sourcefile } } - - Checks of '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 'run-gcov' -command has arguments 'branches' or 'calls', respectively. For example, -the following specifies checking both, as well as passing '-b' to -'gcov': - - { dg-final { run-gcov branches calls { -b sourcefile } } } - - A line count command appears within a comment on the source line that -is expected to get the specified count and has the form 'count(CNT)'. A -test should only check line counts for lines that will get the same -count for any architecture. - - Commands to check branch percentages ('branch') and call return -percentages ('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 'branch(end)' or -'returns(end)' marks the end of a range without starting a new one. For -example: - - if (i > 10 && j > i && j < 20) /* branch(27 50 75) */ - /* branch(end) */ - foo (i, j); - - 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. - - -File: gccint.info, Node: profopt Testing, Next: compat Testing, Prev: gcov Testing, Up: Testsuites - -7.8 Support for testing profile-directed optimizations -====================================================== - -The 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. -'profopt.exp' has the beginnings of this kind of support. - - 'profopt.exp' provides generic support for profile-directed -optimizations. Each set of tests that uses it provides information -about a specific optimization: - -'tool' - tool being tested, e.g., 'gcc' - -'profile_option' - options used to generate profile data - -'feedback_option' - options used to optimize using that profile data - -'prof_ext' - suffix of profile data files - -'PROFOPT_OPTIONS' - list of options with which to run each test, similar to the lists - for torture tests - -'{ dg-final-generate { LOCAL-DIRECTIVE } }' - This directive is similar to 'dg-final', but the LOCAL-DIRECTIVE is - run after the generation of profile data. - -'{ dg-final-use { LOCAL-DIRECTIVE } }' - The LOCAL-DIRECTIVE is run after the profile data have been used. - - -File: gccint.info, Node: compat Testing, Next: Torture Tests, Prev: profopt Testing, Up: Testsuites - -7.9 Support for testing binary compatibility -============================================ - -The 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. - -'TESTNAME_main.SUFFIX' - Contains the main program, which calls a function in file - 'TESTNAME_x.SUFFIX'. - -'TESTNAME_x.SUFFIX' - Contains at least one call to a function in 'TESTNAME_y.SUFFIX'. - -'TESTNAME_y.SUFFIX' - Shares data with, or gets arguments from, 'TESTNAME_x.SUFFIX'. - - 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. - - 'compat.exp' defines default pairs of compiler options. These can be -overridden by defining the environment variable 'COMPAT_OPTIONS' as: - - COMPAT_OPTIONS="[list [list {TST1} {ALT1}] - ...[list {TSTN} {ALTN}]]" - - where TSTI and ALTI are lists of options, with TSTI used by the -compiler under test and ALTI used by the alternate compiler. For -example, with '[list [list {-g -O0} {-O3}] [list {-fpic} {-fPIC -O2}]]', -the test is first built with '-g -O0' by the compiler under test and -with '-O3' by the alternate compiler. The test is built a second time -using '-fpic' by the compiler under test and '-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 -'ALT_CC_UNDER_TEST', and for C++ define 'ALT_CXX_UNDER_TEST'. These -will be written to the '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 'COMPAT_OPTIONS'. When -'ALT_CC_UNDER_TEST' or 'ALT_CXX_UNDER_TEST' is 'same', each test is -built using the compiler under test but with combinations of the options -from '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 'OBJDIR/gcc': - - rm site.exp - make -k \ - ALT_CXX_UNDER_TEST=${alt_prefix}/bin/g++ \ - COMPAT_OPTIONS="LISTS AS SHOWN ABOVE" \ - check-c++ \ - RUNTESTFLAGS="compat.exp" - - 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. - -'dg-require-*' - These commands can be used in 'TESTNAME_main.SUFFIX' to skip the - test if specific support is not available on the target. - -'dg-options' - The specified options are used for compiling this particular source - file, appended to the options from 'COMPAT_OPTIONS'. When this - command appears in 'TESTNAME_main.SUFFIX' the options are also used - to link the test program. - -'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. - - -File: gccint.info, Node: Torture Tests, Prev: compat Testing, Up: Testsuites - -7.10 Support for torture testing using multiple options -======================================================= - -Throughout the compiler testsuite there are several directories whose -tests are run multiple times, each with a different set of options. -These are known as torture tests. 'lib/torture-options.exp' defines -procedures to set up these lists: - -'torture-init' - Initialize use of torture lists. -'set-torture-options' - Set lists of torture options to use for tests with and without - loops. Optionally combine a set of torture options with a set of - other options, as is done with Objective-C runtime options. -'torture-finish' - Finalize use of torture lists. - - The '.exp' file for a set of tests that use torture options must -include calls to these three procedures if: - - * It calls 'gcc-dg-runtest' and overrides DG_TORTURE_OPTIONS. - - * It calls ${TOOL}'-torture' or ${TOOL}'-torture-execute', where TOOL - is 'c', 'fortran', or 'objc'. - - * It calls 'dg-pch'. - - It is not necessary for a '.exp' file that calls 'gcc-dg-runtest' to -call the torture procedures if the tests should use the list in -DG_TORTURE_OPTIONS defined in 'gcc-dg.exp'. - - Most uses of torture options can override the default lists by defining -TORTURE_OPTIONS or add to the default list by defining -ADDITIONAL_TORTURE_OPTIONS. Define these in a '.dejagnurc' file or add -them to the 'site.exp' file; for example - - set ADDITIONAL_TORTURE_OPTIONS [list \ - { -O2 -ftree-loop-linear } \ - { -O2 -fpeel-loops } ] - - -File: gccint.info, Node: Options, Next: Passes, Prev: Testsuites, Up: Top - -8 Option specification files -**************************** - -Most GCC command-line options are described by special option definition -files, the names of which conventionally end in '.opt'. This chapter -describes the format of these files. - -* Menu: - -* Option file format:: The general layout of the files -* Option properties:: Supported option properties - - -File: gccint.info, Node: Option file format, Next: Option properties, Up: Options - -8.1 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: - - * A language definition record. These records have two fields: the - string 'Language' and the name of the language. Once a language - has been declared in this way, it can be used as an option - property. *Note Option properties::. - - * A target specific save record to save additional information. - These records have two fields: the string 'TargetSave', and a - declaration type to go in the 'cl_target_option' structure. - - * A variable record to define a variable used to store option - information. These records have two fields: the string 'Variable', - and a declaration of the type and name of the variable, optionally - with an initializer (but without any trailing ';'). These records - may be used for variables used for many options where declaring the - initializer in a single option definition record, or duplicating it - in many records, would be inappropriate, or for variables set in - option handlers rather than referenced by 'Var' properties. - - * A variable record to define a variable used to store option - information. These records have two fields: the string - 'TargetVariable', and a declaration of the type and name of the - variable, optionally with an initializer (but without any trailing - ';'). 'TargetVariable' is a combination of 'Variable' and - 'TargetSave' records in that the variable is defined in the - 'gcc_options' structure, but these variables are also stored in the - 'cl_target_option' structure. The variables are saved in the - target save code and restored in the target restore code. - - * A variable record to record any additional files that the - 'options.h' file should include. This is useful to provide - enumeration or structure definitions needed for target variables. - These records have two fields: the string 'HeaderInclude' and the - name of the include file. - - * A variable record to record any additional files that the - 'options.c' or 'options-save.c' file should include. This is - useful to provide inline functions needed for target variables - and/or '#ifdef' sequences to properly set up the initialization. - These records have two fields: the string 'SourceInclude' and the - name of the include file. - - * An enumeration record to define a set of strings that may be used - as arguments to an option or options. These records have three - fields: the string 'Enum', a space-separated list of properties and - help text used to describe the set of strings in '--help' output. - Properties use the same format as option properties; the following - are valid: - 'Name(NAME)' - This property is required; NAME must be a name (suitable for - use in C identifiers) used to identify the set of strings in - 'Enum' option properties. - - 'Type(TYPE)' - This property is required; TYPE is the C type for variables - set by options using this enumeration together with 'Var'. - - 'UnknownError(MESSAGE)' - The message MESSAGE will be used as an error message if the - argument is invalid; for enumerations without 'UnknownError', - a generic error message is used. MESSAGE should contain a - single '%qs' format, which will be used to format the invalid - argument. - - * An enumeration value record to define one of the strings in a set - given in an 'Enum' record. These records have two fields: the - string 'EnumValue' and a space-separated list of properties. - Properties use the same format as option properties; the following - are valid: - 'Enum(NAME)' - This property is required; NAME says which 'Enum' record this - 'EnumValue' record corresponds to. - - 'String(STRING)' - This property is required; STRING is the string option - argument being described by this record. - - 'Value(VALUE)' - This property is required; it says what value (representable - as 'int') should be used for the given string. - - 'Canonical' - This property is optional. If present, it says the present - string is the canonical one among all those with the given - value. Other strings yielding that value will be mapped to - this one so specs do not need to handle them. - - 'DriverOnly' - This property is optional. If present, the present string - will only be accepted by the driver. This is used for cases - such as '-march=native' that are processed by the driver so - that 'gcc -v' shows how the options chosen depended on the - system on which the compiler was run. - - * An option definition record. These records have the following - fields: - 1. the name of the option, with the leading "-" removed - 2. a space-separated list of option properties (*note Option - properties::) - 3. the help text to use for '--help' (omitted if the second field - contains the 'Undocumented' property). - - 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 - '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. - - * A target mask record. These records have one field of the form - 'Mask(X)'. The options-processing script will automatically - allocate a bit in 'target_flags' (*note Run-time Target::) for each - mask name X and set the macro 'MASK_X' to the appropriate bitmask. - It will also declare a 'TARGET_X' macro that has the value 1 when - bit 'MASK_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. - - -File: gccint.info, Node: Option properties, Prev: Option file format, Up: Options - -8.2 Option properties -===================== - -The second field of an option record can specify any of the following -properties. When an option takes an argument, it is enclosed in -parentheses following the option property name. The parser that handles -option files is quite simplistic, and will be tricked by any nested -parentheses within the argument text itself; in this case, the entire -option argument can be wrapped in curly braces within the parentheses to -demarcate it, e.g.: - - Condition({defined (USE_CYGWIN_LIBSTDCXX_WRAPPERS)}) - -'Common' - The option is available for all languages and targets. - -'Target' - The option is available for all languages but is target-specific. - -'Driver' - The option is handled by the compiler driver using code not shared - with the compilers proper ('cc1' etc.). - -'LANGUAGE' - The option is available when compiling for the given language. - - It is possible to specify several different languages for the same - option. Each LANGUAGE must have been declared by an earlier - 'Language' record. *Note Option file format::. - -'RejectDriver' - The option is only handled by the compilers proper ('cc1' etc.) and - should not be accepted by the driver. - -'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. - -'Negative(OTHERNAME)' - The option will turn off another option OTHERNAME, which is the - option name with the leading "-" removed. This chain action will - propagate through the 'Negative' property of the option to be - turned off. - - As a consequence, if you have a group of mutually-exclusive - options, their 'Negative' properties should form a circular chain. - For example, if options '-A', '-B' and '-C' are mutually exclusive, - their respective 'Negative' properties should be 'Negative(B)', - 'Negative(C)' and 'Negative(A)'. - -'Joined' -'Separate' - The option takes a mandatory argument. 'Joined' indicates that the - option and argument can be included in the same 'argv' entry (as - with '-mflush-func=NAME', for example). 'Separate' indicates that - the option and argument can be separate 'argv' entries (as with - '-o'). An option is allowed to have both of these properties. - -'JoinedOrMissing' - The option takes an optional argument. If the argument is given, - it will be part of the same 'argv' entry as the option itself. - - This property cannot be used alongside 'Joined' or 'Separate'. - -'MissingArgError(MESSAGE)' - For an option marked 'Joined' or 'Separate', the message MESSAGE - will be used as an error message if the mandatory argument is - missing; for options without 'MissingArgError', a generic error - message is used. MESSAGE should contain a single '%qs' format, - which will be used to format the name of the option passed. - -'Args(N)' - For an option marked 'Separate', indicate that it takes N - arguments. The default is 1. - -'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. 'UInteger' should also be used on options - like '-falign-loops' where both '-falign-loops' and - '-falign-loops'=N are supported to make sure the saved options are - given a full integer. - -'ToLower' - The option's argument should be converted to lowercase as part of - putting it in canonical form, and before comparing with the strings - indicated by any 'Enum' property. - -'NoDriverArg' - For an option marked 'Separate', the option only takes an argument - in the compiler proper, not in the driver. This is for - compatibility with existing options that are used both directly and - via '-Wp,'; new options should not have this property. - -'Var(VAR)' - The state of this option should be stored in variable VAR (actually - a macro for 'global_options.x_VAR'). The way that the state is - stored depends on the type of option: - - * If the option uses the 'Mask' or 'InverseMask' properties, VAR - is the integer variable that contains the mask. - - * If the option is a normal on/off switch, 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. - - * If the option takes an argument and has the 'UInteger' - property, VAR is an integer variable that stores the value of - the argument. - - * If the option takes an argument and has the 'Enum' property, - VAR is a variable (type given in the 'Type' property of the - 'Enum' record whose 'Name' property has the same argument as - the 'Enum' property of this option) that stores the value of - the argument. - - * If the option has the 'Defer' property, VAR is a pointer to a - 'VEC(cl_deferred_option,heap)' that stores the option for - later processing. (VAR is declared with type 'void *' and - needs to be cast to 'VEC(cl_deferred_option,heap)' before - use.) - - * Otherwise, if the option takes an argument, VAR is a pointer - to the argument string. The pointer will be null if the - argument is optional and wasn't given. - - The option-processing script will usually zero-initialize VAR. You - can modify this behavior using 'Init'. - -'Var(VAR, SET)' - The option controls an integer variable VAR and is active when VAR - equals SET. The option parser will set VAR to SET when the - positive form of the option is used and '!SET' when the "no-" form - is used. - - VAR is declared in the same way as for the single-argument form - described above. - -'Init(VALUE)' - The variable specified by the 'Var' property should be statically - initialized to VALUE. If more than one option using the same - variable specifies 'Init', all must specify the same initializer. - -'Mask(NAME)' - The option is associated with a bit in the 'target_flags' variable - (*note Run-time Target::) and is active when that bit is set. You - may also specify 'Var' to select a variable other than - 'target_flags'. - - The options-processing script will automatically allocate a unique - bit for the option. If the option is attached to 'target_flags', - the script will set the macro 'MASK_NAME' to the appropriate - bitmask. It will also declare a 'TARGET_NAME' macro that has the - value 1 when the option is active and 0 otherwise. If you use - 'Var' to attach the option to a different variable, the bitmask - macro with be called 'OPTION_MASK_NAME'. - -'InverseMask(OTHERNAME)' -'InverseMask(OTHERNAME, THISNAME)' - The option is the inverse of another option that has the - 'Mask(OTHERNAME)' property. If THISNAME is given, the - options-processing script will declare a 'TARGET_THISNAME' macro - that is 1 when the option is active and 0 otherwise. - -'Enum(NAME)' - The option's argument is a string from the set of strings - associated with the corresponding 'Enum' record. The string is - checked and converted to the integer specified in the corresponding - 'EnumValue' record before being passed to option handlers. - -'Defer' - The option should be stored in a vector, specified with 'Var', for - later processing. - -'Alias(OPT)' -'Alias(OPT, ARG)' -'Alias(OPT, POSARG, NEGARG)' - The option is an alias for '-OPT' (or the negative form of that - option, depending on 'NegativeAlias'). In the first form, any - argument passed to the alias is considered to be passed to '-OPT', - and '-OPT' is considered to be negated if the alias is used in - negated form. In the second form, the alias may not be negated or - have an argument, and POSARG is considered to be passed as an - argument to '-OPT'. In the third form, the alias may not have an - argument, if the alias is used in the positive form then POSARG is - considered to be passed to '-OPT', and if the alias is used in the - negative form then NEGARG is considered to be passed to '-OPT'. - - Aliases should not specify 'Var' or 'Mask' or 'UInteger'. Aliases - should normally specify the same languages as the target of the - alias; the flags on the target will be used to determine any - diagnostic for use of an option for the wrong language, while those - on the alias will be used to identify what command-line text is the - option and what text is any argument to that option. - - When an 'Alias' definition is used for an option, driver specs do - not need to handle it and no 'OPT_' enumeration value is defined - for it; only the canonical form of the option will be seen in those - places. - -'NegativeAlias' - For an option marked with 'Alias(OPT)', the option is considered to - be an alias for the positive form of '-OPT' if negated and for the - negative form of '-OPT' if not negated. 'NegativeAlias' may not be - used with the forms of 'Alias' taking more than one argument. - -'Ignore' - This option is ignored apart from printing any warning specified - using 'Warn'. The option will not be seen by specs and no 'OPT_' - enumeration value is defined for it. - -'SeparateAlias' - For an option marked with 'Joined', 'Separate' and 'Alias', the - option only acts as an alias when passed a separate argument; with - a joined argument it acts as a normal option, with an 'OPT_' - enumeration value. This is for compatibility with the Java '-d' - option and should not be used for new options. - -'Warn(MESSAGE)' - If this option is used, output the warning MESSAGE. MESSAGE is a - format string, either taking a single operand with a '%qs' format - which is the option name, or not taking any operands, which is - passed to the 'warning' function. If an alias is marked 'Warn', - the target of the alias must not also be marked 'Warn'. - -'Report' - The state of the option should be printed by '-fverbose-asm'. - -'Warning' - This is a warning option and should be shown as such in '--help' - output. This flag does not currently affect anything other than - '--help'. - -'Optimization' - This is an optimization option. It should be shown as such in - '--help' output, and any associated variable named using 'Var' - should be saved and restored when the optimization level is changed - with 'optimize' attributes. - -'Undocumented' - The option is deliberately missing documentation and should not be - included in the '--help' output. - -'Condition(COND)' - The option should only be accepted if preprocessor condition COND - is true. Note that any C declarations associated with the option - will be present even if COND is false; COND simply controls whether - the option is accepted and whether it is printed in the '--help' - output. - -'Save' - Build the 'cl_target_option' structure to hold a copy of the - option, add the functions 'cl_target_option_save' and - 'cl_target_option_restore' to save and restore the options. - -'SetByCombined' - The option may also be set by a combined option such as - '-ffast-math'. This causes the 'gcc_options' struct to have a - field 'frontend_set_NAME', where 'NAME' is the name of the field - holding the value of this option (without the leading 'x_'). This - gives the front end a way to indicate that the value has been set - explicitly and should not be changed by the combined option. For - example, some front ends use this to prevent '-ffast-math' and - '-fno-fast-math' from changing the value of '-fmath-errno' for - languages that do not use 'errno'. - -'EnabledBy(OPT)' -'EnabledBy(OPT && OPT2)' - If not explicitly set, the option is set to the value of '-OPT'. - The second form specifies that the option is only set if both OPT - and OPT2 are set. - -'LangEnabledBy(LANGUAGE, OPT)' -'LangEnabledBy(LANGUAGE, OPT, POSARG, NEGARG)' - When compiling for the given language, the option is set to the - value of '-OPT', if not explicitly set. In the second form, if OPT - is used in the positive form then POSARG is considered to be passed - to the option, and if OPT is used in the negative form then NEGARG - is considered to be passed to the option. It is possible to - specify several different languages. Each LANGUAGE must have been - declared by an earlier 'Language' record. *Note Option file - format::. - -'NoDWARFRecord' - The option is omitted from the producer string written by - '-grecord-gcc-switches'. - -'PchIgnore' - Even if this is a target option, this option will not be recorded / - compared to determine if a precompiled header file matches. - - -File: gccint.info, Node: Passes, Next: GENERIC, Prev: Options, Up: Top - -9 Passes and Files of the Compiler -********************************** - -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. -* Cilk Plus Transformation:: Transform Cilk Plus Code to equivalent C/C++. -* 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. -* Optimization info:: Dumping optimization information from passes. - - -File: gccint.info, Node: Parsing pass, Next: Cilk Plus Transformation, Up: Passes - -9.1 Parsing pass -================ - -The language front end is invoked only once, via -'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 (*note GENERIC::), plus a double -handful of language specific tree codes defined in 'c-common.def'. The -Fortran front end uses a completely different private 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 (*note GIMPLE::) on each -function, and uses the gimplifier callbacks to convert the -language-specific tree nodes directly to GIMPLE 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... 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 _definitions_ be passed to the middle-end. For -complete debug information, function, data and type declarations should -all be passed as well. - - In any case, the front end needs each complete top-level function or -data declaration, and each data definition should be passed to -'rest_of_decl_compilation'. Each complete type definition should be -passed to 'rest_of_type_compilation'. Each function definition should -be passed to '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. - - -File: gccint.info, Node: Cilk Plus Transformation, Next: Gimplification pass, Prev: Parsing pass, Up: Passes - -9.2 Cilk Plus Transformation -============================ - -If Cilk Plus generation (flag '-fcilkplus') is enabled, all the Cilk -Plus code is transformed into equivalent C and C++ functions. Majority -of this transformation occurs toward the end of the parsing and right -before the gimplification pass. - - These are the major components to the Cilk Plus language extension: - * Array Notations: During parsing phase, all the array notation - specific information is stored in 'ARRAY_NOTATION_REF' tree using - the function 'c_parser_array_notation'. During the end of parsing, - we check the entire function to see if there are any array notation - specific code (using the function 'contains_array_notation_expr'). - If this function returns true, then we expand them using either - 'expand_array_notation_exprs' or 'build_array_notation_expr'. For - the cases where array notations are inside conditions, they are - transformed using the function 'fix_conditional_array_notations'. - The C language-specific routines are located in - 'c/c-array-notation.c' and the equivalent C++ routines are in the - file 'cp/cp-array-notation.c'. Common routines such as functions - to initialize built-in functions are stored in - 'array-notation-common.c'. - - * Cilk keywords: - * '_Cilk_spawn': The '_Cilk_spawn' keyword is parsed and the - function it contains is marked as a spawning function. The - spawning function is called the spawner. At the end of the - parsing phase, appropriate built-in functions are added to the - spawner that are defined in the Cilk runtime. The appropriate - locations of these functions, and the internal structures are - detailed in 'cilk_init_builtins' in the file 'cilk-common.c'. - The pointers to Cilk functions and fields of internal - structures are described in 'cilk.h'. The built-in functions - are described in 'cilk-builtins.def'. - - During gimplification, a new "spawn-helper" function is - created. The spawned function is replaced with a spawn helper - function in the spawner. The spawned function-call is moved - into the spawn helper. The main function that does these - transformations is 'gimplify_cilk_spawn' in 'c-family/cilk.c'. - In the spawn-helper, the gimplification function - 'gimplify_call_expr', inserts a function call - '__cilkrts_detach'. This function is expanded by - 'builtin_expand_cilk_detach' located in 'c-family/cilk.c'. - - * '_Cilk_sync': '_Cilk_sync' is parsed like a keyword. During - gimplification, the function 'gimplify_cilk_sync' in - 'c-family/cilk.c', will replace this keyword with a set of - functions that are stored in the Cilk runtime. One of the - internal functions inserted during gimplification, - '__cilkrts_pop_frame' must be expanded by the compiler and is - done by 'builtin_expand_cilk_pop_frame' in 'cilk-common.c'. - - Documentation about Cilk Plus and language specification is provided -under the "Learn" section in <http://www.cilkplus.org/>. It is worth -mentioning that the current implementation follows ABI 1.1. - - -File: gccint.info, Node: Gimplification pass, Next: Pass manager, Prev: Cilk Plus Transformation, Up: Passes - -9.3 Gimplification pass -======================= - -"Gimplification" is a whimsical term for the process of converting the -intermediate representation of a function into the GIMPLE language -(*note GIMPLE::). The term stuck, and so words like "gimplification", -"gimplify", "gimplifier" and the like are sprinkled throughout this -section of code. - - 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. - - The main entry point to this pass is 'gimplify_function_tree' located -in 'gimplify.c'. From here we process the entire function gimplifying -each statement in turn. The main workhorse for this pass is -'gimplify_expr'. Approximately everything passes through here at least -once, and it is from here that we invoke the 'lang_hooks.gimplify_expr' -callback. - - The callback should examine the expression in question and return -'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 'GS_ALL_DONE'. -Otherwise it should return '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 'GS_ERROR'. - - -File: gccint.info, Node: Pass manager, Next: Tree SSA passes, Prev: Gimplification pass, Up: Passes - -9.4 Pass manager -================ - -The pass manager is located in 'passes.c', 'tree-optimize.c' and -'tree-pass.h'. It processes passes as described in 'passes.def'. 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 '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. - - Each pass should have a unique name. Each pass may have its own dump -file (for GCC debugging purposes). Passes with a name starting with a -star do not dump anything. Sometimes passes are supposed to share a -dump file / option name. To still give these unique names, you can use -a prefix that is delimited by a space from the part that is used for the -dump file / option name. E.g. When the pass name is "ud dce", the name -used for dump file/options is "dce". - - 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... - - -File: gccint.info, Node: Tree SSA passes, Next: RTL passes, Prev: Pass manager, Up: Passes - -9.5 Tree SSA passes -=================== - -The following briefly describes the Tree optimization passes that are -run after gimplification and what source files they are located in. - - * 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 '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 - 'tree-cfg.c' and described by 'pass_remove_useless_stmts'. - - * OpenMP lowering - - If OpenMP generation ('-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 'omp-low.c' and is - described by 'pass_lower_omp'. - - * OpenMP expansion - - If OpenMP generation ('-fopenmp') is enabled, this pass expands - parallel regions into their own functions to be invoked by the - thread library. The pass is located in 'omp-low.c' and is - described by 'pass_expand_omp'. - - * Lower control flow - - This pass flattens 'if' statements ('COND_EXPR') and moves lexical - bindings ('BIND_EXPR') out of line. After this pass, all 'if' - statements will have exactly two 'goto' statements in its 'then' - and 'else' arms. Lexical binding information for each statement - will be found in 'TREE_BLOCK' rather than being inferred from its - position under a 'BIND_EXPR'. This pass is found in 'gimple-low.c' - and is described by 'pass_lower_cf'. - - * Lower exception handling control flow - - This pass decomposes high-level exception handling constructs - ('TRY_FINALLY_EXPR' and 'TRY_CATCH_EXPR') into a form that - explicitly represents the control flow involved. After this pass, - 'lookup_stmt_eh_region' will return a non-negative number for any - statement that may have EH control flow semantics; examine - 'tree_can_throw_internal' or 'tree_can_throw_external' for exact - semantics. Exact control flow may be extracted from - 'foreach_reachable_handler'. The EH region nesting tree is defined - in 'except.h' and built in 'except.c'. The lowering pass itself is - in 'tree-eh.c' and is described by 'pass_lower_eh'. - - * 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 'tree-cfg.c' and - is described by 'pass_build_cfg'. - - * Find all referenced variables - - This pass walks the entire function and collects an array of all - variables referenced in the function, '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 'tree-dfa.c' and is - described by 'pass_referenced_vars'. - - * Enter static single assignment form - - This pass rewrites the function such that it is in SSA form. After - this pass, all 'is_gimple_reg' variables will be referenced by - 'SSA_NAME', and all occurrences of other variables will be - annotated with 'VDEFS' and 'VUSES'; PHI nodes will have been - inserted as necessary for each basic block. This pass is located - in 'tree-ssa.c' and is described by 'pass_build_ssa'. - - * Warn for uninitialized variables - - This pass scans the function for uses of '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 (if turned on). 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 - 'tree-ssa.c' and is defined by 'pass_early_warn_uninitialized' and - 'pass_late_warn_uninitialized'. - - * 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 'tree-ssa-dce.c' and is described by 'pass_dce'. - - * 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 is - located in 'tree-ssa-dom.c' and is described by 'pass_dominator'. - - * 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 - 'tree-ssa-forwprop.c' and is described by 'pass_forwprop'. - - * 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 - 'tree-ssa-copyrename.c' and is described by 'pass_copyrename'. - - * 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 'tree-ssa-phiopt.c' and is described by - 'pass_phiopt'. - - * 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 'VDEF'/'VUSE' memory tags for non-renameable - aggregates so that we get fewer false kills. The pass is located - in 'tree-ssa-alias.c' and is described by 'pass_may_alias'. - - Interprocedural points-to information is located in - 'tree-ssa-structalias.c' and described by 'pass_ipa_pta'. - - * 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 'predict.c' - and is described by 'pass_profile'. - - * Lower complex arithmetic - - This pass rewrites complex arithmetic operations into their - component scalar arithmetic operations. The pass is located in - 'tree-complex.c' and is described by 'pass_lower_complex'. - - * 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 'tree-sra.c' and is described by 'pass_sra'. - - * 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 'tree-ssa-dse.c' and is described by 'pass_dse'. - - * Tail recursion elimination - - This pass transforms tail recursion into a loop. It is located in - 'tree-tailcall.c' and is described by 'pass_tail_recursion'. - - * Forward store motion - - This pass sinks stores and assignments down the flowgraph closer to - their use point. The pass is located in 'tree-ssa-sink.c' and is - described by 'pass_sink_code'. - - * Partial redundancy elimination - - This pass eliminates partially redundant computations, as well as - performing load motion. The pass is located in 'tree-ssa-pre.c' - and is described by 'pass_pre'. - - Just before partial redundancy elimination, if - '-funsafe-math-optimizations' is on, GCC tries to convert divisions - to multiplications by the reciprocal. The pass is located in - 'tree-ssa-math-opts.c' and is described by 'pass_cse_reciprocal'. - - * Full redundancy elimination - - This is a simpler form of PRE that only eliminates redundancies - that occur on all paths. It is located in 'tree-ssa-pre.c' and - described by 'pass_fre'. - - * Loop optimization - - The main driver of the pass is placed in 'tree-ssa-loop.c' and - described by '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 '-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 '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 '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 '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 'tree-ssa-loop-unswitch.c'. This pass - should eventually replace the RTL level loop unswitching in - '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 - 'tree-ssa-loop-manip.c', 'cfgloop.c', 'cfgloopanal.c' and - '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 'VF' (vectorization factor), which is the - number of elements operated upon in parallel in each iteration, and - the '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 - 'tree-vectorizer.c' (the main driver), 'tree-vect-loop.c' and - 'tree-vect-loop-manip.c' (loop specific parts and general loop - utilities), 'tree-vect-slp' (loop-aware SLP functionality), - 'tree-vect-stmts.c' and 'tree-vect-data-refs.c'. Analysis of data - references is in 'tree-data-ref.c'. - - SLP Vectorization. This pass performs vectorization of - straight-line code. The pass is implemented in 'tree-vectorizer.c' - (the main driver), 'tree-vect-slp.c', 'tree-vect-stmts.c' and - 'tree-vect-data-refs.c'. - - Autoparallelization. This pass splits the loop iteration space to - run into several threads. The pass is implemented in - 'tree-parloops.c'. - - Graphite is a loop transformation framework based on the polyhedral - model. Graphite stands for Gimple Represented as Polyhedra. The - internals of this infrastructure are documented in - <http://gcc.gnu.org/wiki/Graphite>. The passes working on this - representation are implemented in the various 'graphite-*' files. - - * 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 pass is located - in 'tree-if-conv.c' and is described by 'pass_if_conversion'. - - * 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 'tree-ssa-ccp.c' and is described by - 'pass_ccp'. - - A related pass that works on memory loads and stores, and not just - register values, is located in 'tree-ssa-ccp.c' and described by - 'pass_store_ccp'. - - * 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 'tree-ssa-copy.c' and described by - 'pass_copy_prop'. - - A related pass that works on memory copies, and not just register - copies, is located in 'tree-ssa-copy.c' and described by - 'pass_store_copy_prop'. - - * 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 'tree-vrp.c' and is described by 'pass_vrp'. - - * Folding built-in functions - - This pass simplifies built-in functions, as applicable, with - constant arguments or with inferable string lengths. It is located - in 'tree-ssa-ccp.c' and is described by 'pass_fold_builtins'. - - * 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 - 'tree-cfg.c' and is described by 'pass_split_crit_edges'. - - * 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 - 'tree-ssa-dce.c' and is described by 'pass_cd_dce'. - - * 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 'CALL_EXPR_TAILCALL' is set indicating the possibility. - The pass is located in 'tree-tailcall.c' and is described by - 'pass_tail_calls'. The RTL transformation is handled by - 'fixup_tail_calls' in 'calls.c'. - - * 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 'tree-cfg.c' - and is described by 'pass_warn_function_return'. - - * 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 'tree-outof-ssa.c' and is - described by 'pass_del_ssa'. - - * 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 'tree-cfgcleanup.c' and is described by - 'pass_merge_phi'. - - * 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 - 'tree-nrv.c' and is described by 'pass_nrv'. - - * Return slot optimization - - If a function returns a memory object and is called as 'var = - foo()', this pass tries to change the call so that the address of - 'var' is sent to the caller to avoid an extra memory copy. This - pass is located in 'tree-nrv.c' and is described by - 'pass_return_slot'. - - * Optimize calls to '__builtin_object_size' - - This is a propagation pass similar to CCP that tries to remove - calls to '__builtin_object_size' when the size of the object can be - computed at compile-time. This pass is located in - 'tree-object-size.c' and is described by 'pass_object_sizes'. - - * Loop invariant motion - - This pass removes expensive loop-invariant computations out of - loops. The pass is located in 'tree-ssa-loop.c' and described by - 'pass_lim'. - - * 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 'tree-loop-linear.c' and described by - 'pass_linear_transform'. - - * Removal of empty loops - - This pass removes loops with no code in them. The pass is located - in 'tree-ssa-loop-ivcanon.c' and described by 'pass_empty_loop'. - - * Unrolling of small loops - - This pass completely unrolls loops with few iterations. The pass - is located in 'tree-ssa-loop-ivcanon.c' and described by - 'pass_complete_unroll'. - - * Predictive commoning - - This pass makes the code reuse the computations from the previous - iterations of the loops, especially loads and stores to memory. It - does so by storing the values of these computations to a bank of - temporary variables that are rotated at the end of loop. To avoid - the need for this rotation, the loop is then unrolled and the - copies of the loop body are rewritten to use the appropriate - version of the temporary variable. This pass is located in - 'tree-predcom.c' and described by 'pass_predcom'. - - * Array prefetching - - This pass issues prefetch instructions for array references inside - loops. The pass is located in 'tree-ssa-loop-prefetch.c' and - described by 'pass_loop_prefetch'. - - * Reassociation - - This pass rewrites arithmetic expressions to enable optimizations - that operate on them, like redundancy elimination and - vectorization. The pass is located in 'tree-ssa-reassoc.c' and - described by 'pass_reassoc'. - - * Optimization of 'stdarg' functions - - This pass tries to avoid the saving of register arguments into the - stack on entry to 'stdarg' functions. If the function doesn't use - any 'va_start' macros, no registers need to be saved. If - 'va_start' macros are used, the 'va_list' variables don't escape - the function, it is only necessary to save registers that will be - used in 'va_arg' macros. For instance, if '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 'tree-stdarg.c' and - described by 'pass_stdarg'. - - -File: gccint.info, Node: RTL passes, Next: Optimization info, Prev: Tree SSA passes, Up: Passes - -9.6 RTL passes -============== - -The following briefly describes the RTL generation and optimization -passes that are run after the Tree optimization passes. - - * RTL generation - - The source files for RTL generation include 'stmt.c', 'calls.c', - 'expr.c', 'explow.c', 'expmed.c', 'function.c', 'optabs.c' and - 'emit-rtl.c'. Also, the file 'insn-emit.c', generated from the - machine description by the program 'genemit', is used in this pass. - The header file 'expr.h' is used for communication within this - pass. - - The header files 'insn-flags.h' and 'insn-codes.h', generated from - the machine description by the programs 'genflags' and 'gencodes', - tell this pass which standard names are available for use and which - patterns correspond to them. - - * Generation of exception 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 "landing pads". The - code for this pass is located in 'except.c'. - - * Control flow graph cleanup - - 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 - 'cfgcleanup.c', and there are support routines in 'cfgrtl.c' and - 'jump.c'. - - * Forward propagation of single-def values - - This pass attempts to remove redundant computation by substituting - variables that come from a single definition, and seeing if the - result can be simplified. It performs copy propagation and - addressing mode selection. The pass is run twice, with values - being propagated into loops only on the second run. The code is - located in 'fwprop.c'. - - * Common subexpression elimination - - This pass removes redundant computation within basic blocks, and - optimizes addressing modes based on cost. The pass is run twice. - The code for this pass is located in 'cse.c'. - - * 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 'gcse.c', and the LCM routines are in 'lcm.c'. - - * Loop optimization - - This pass performs several loop related optimizations. The source - files 'cfgloopanal.c' and 'cfgloopmanip.c' contain generic loop - analysis and manipulation code. Initialization and finalization of - loop structures is handled by 'loop-init.c'. A loop invariant - motion pass is implemented in 'loop-invariant.c'. Basic block - level optimizations--unrolling, peeling and unswitching loops-- are - implemented in 'loop-unswitch.c' and 'loop-unroll.c'. Replacing of - the exit condition of loops by special machine-dependent - instructions is handled by 'loop-doloop.c'. - - * 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 'gcse.c'. - - * 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/LRA, it will generate predicated - instructions when supported by the target. The code is located in - 'ifcvt.c'. - - * 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. The code for this pass is located in 'web.c'. - - * 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 code is located in - 'combine.c'. - - * Mode switching optimization - - 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 code for this pass is - located in 'mode-switching.c'. - - * 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 code for - this pass is located in 'modulo-sched.c'. - - * 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 code for this pass is located - in 'haifa-sched.c', 'sched-deps.c', 'sched-ebb.c', 'sched-rgn.c' - and 'sched-vis.c'. - - * 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: - - * The integrated register allocator (IRA). It is called - integrated because coalescing, register live range splitting, - and hard register preferencing are done on-the-fly during - coloring. It also has better integration with the reload/LRA - pass. Pseudo-registers spilled by the allocator or the - reload/LRA have still a chance to get hard-registers if the - reload/LRA evicts some pseudo-registers from hard-registers. - The allocator helps to choose better pseudos for spilling - based on their live ranges and to coalesce stack slots - allocated for the spilled pseudo-registers. IRA is a regional - register allocator which is transformed into Chaitin-Briggs - allocator if there is one region. By default, IRA chooses - regions using register pressure but the user can force it to - use one region or regions corresponding to all loops. - - Source files of the allocator are 'ira.c', 'ira-build.c', - 'ira-costs.c', 'ira-conflicts.c', 'ira-color.c', 'ira-emit.c', - 'ira-lives', plus header files 'ira.h' and 'ira-int.h' used - for the communication between the allocator and the rest of - the compiler and between the IRA files. - - * 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 'reload.c' and 'reload1.c', plus the header - 'reload.h' used for communication between them. - - * This pass is a modern replacement of the reload pass. Source - files are 'lra.c', 'lra-assign.c', 'lra-coalesce.c', - 'lra-constraints.c', 'lra-eliminations.c', 'lra-equivs.c', - 'lra-lives.c', 'lra-saves.c', 'lra-spills.c', the header - 'lra-int.h' used for communication between them, and the - header 'lra.h' used for communication between LRA and the rest - of compiler. - - Unlike the reload pass, intermediate LRA decisions are - reflected in RTL as much as possible. This reduces the number - of target-dependent macros and hooks, leaving instruction - constraints as the primary source of control. - - LRA is run on targets for which TARGET_LRA_P returns true. - - * 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 'bb-reorder.c', and the various prediction - routines are in 'predict.c'. - - * 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. The code is located in 'var-tracking.c'. - - * 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 code for this pass is located in 'reorg.c'. - - * 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. The code for this pass is located in - 'final.c'. - - * 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 code for this pass is located in 'reg-stack.c'. - - * Final - - This pass outputs the assembler code for the function. The source - files are 'final.c' plus 'insn-output.c'; the latter is generated - automatically from the machine description by the tool 'genoutput'. - The header file 'conditions.h' is used for communication between - these files. - - * 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 'dbxout.c' for DBX symbol table format, 'sdbout.c' - for SDB symbol table format, 'dwarfout.c' for DWARF symbol table - format, files 'dwarf2out.c' and 'dwarf2asm.c' for DWARF2 symbol - table format, and 'vmsdbgout.c' for VMS debug symbol table format. - - -File: gccint.info, Node: Optimization info, Prev: RTL passes, Up: Passes - -9.7 Optimization info -===================== - -This section is describes dump infrastructure which is common to both -pass dumps as well as optimization dumps. The goal for this -infrastructure is to provide both gcc developers and users detailed -information about various compiler transformations and optimizations. - -* Menu: - -* Dump setup:: Setup of optimization dumps. -* Optimization groups:: Groups made up of optimization passes. -* Dump files and streams:: Dump output file names and streams. -* Dump output verbosity:: How much information to dump. -* Dump types:: Various types of dump functions. -* Dump examples:: Sample usage. - - -File: gccint.info, Node: Dump setup, Next: Optimization groups, Up: Optimization info - -9.7.1 Dump setup ----------------- - -A dump_manager class is defined in 'dumpfile.h'. Various passes -register dumping pass-specific information via 'dump_register' in -'passes.c'. During the registration, an optimization pass can select -its optimization group (*note Optimization groups::). After that -optimization information corresponding to the entire group (presumably -from multiple passes) can be output via command-line switches. Note -that if a pass does not fit into any of the pre-defined groups, it can -select 'OPTGROUP_NONE'. - - Note that in general, a pass need not know its dump output file name, -whether certain flags are enabled, etc. However, for legacy reasons, -passes could also call 'dump_begin' which returns a stream in case the -particular pass has optimization dumps enabled. A pass could call -'dump_end' when the dump has ended. These methods should go away once -all the passes are converted to use the new dump infrastructure. - - The recommended way to setup the dump output is via 'dump_start' and -'dump_end'. - - -File: gccint.info, Node: Optimization groups, Next: Dump files and streams, Prev: Dump setup, Up: Optimization info - -9.7.2 Optimization groups -------------------------- - -The optimization passes are grouped into several categories. Currently -defined categories in 'dumpfile.h' are - -'OPTGROUP_IPA' - IPA optimization passes. Enabled by '-ipa' - -'OPTGROUP_LOOP' - Loop optimization passes. Enabled by '-loop'. - -'OPTGROUP_INLINE' - Inlining passes. Enabled by '-inline'. - -'OPTGROUP_VEC' - Vectorization passes. Enabled by '-vec'. - -'OPTGROUP_OTHER' - All other optimization passes which do not fall into one of the - above. - -'OPTGROUP_ALL' - All optimization passes. Enabled by '-all'. - - By using groups a user could selectively enable optimization -information only for a group of passes. By default, the optimization -information for all the passes is dumped. - - -File: gccint.info, Node: Dump files and streams, Next: Dump output verbosity, Prev: Optimization groups, Up: Optimization info - -9.7.3 Dump files and streams ----------------------------- - -There are two separate output streams available for outputting -optimization information from passes. Note that both these streams -accept 'stderr' and 'stdout' as valid streams and thus it is possible to -dump output to standard output or error. This is specially handy for -outputting all available information in a single file by redirecting -'stderr'. - -'pstream' - This stream is for pass-specific dump output. For example, - '-fdump-tree-vect=foo.v' dumps tree vectorization pass output into - the given file name 'foo.v'. If the file name is not provided, the - default file name is based on the source file and pass number. - Note that one could also use special file names 'stdout' and - 'stderr' for dumping to standard output and standard error - respectively. - -'alt_stream' - This steam is used for printing optimization specific output in - response to the '-fopt-info'. Again a file name can be given. If - the file name is not given, it defaults to 'stderr'. - - -File: gccint.info, Node: Dump output verbosity, Next: Dump types, Prev: Dump files and streams, Up: Optimization info - -9.7.4 Dump output verbosity ---------------------------- - -The dump verbosity has the following options - -'optimized' - Print information when an optimization is successfully applied. It - is up to a pass to decide which information is relevant. For - example, the vectorizer passes print the source location of loops - which got successfully vectorized. - -'missed' - Print information about missed optimizations. Individual passes - control which information to include in the output. For example, - - gcc -O2 -ftree-vectorize -fopt-info-vec-missed - - will print information about missed optimization opportunities from - vectorization passes on stderr. - -'note' - Print verbose information about optimizations, such as certain - transformations, more detailed messages about decisions etc. - -'all' - Print detailed optimization information. This includes OPTIMIZED, - MISSED, and NOTE. - - -File: gccint.info, Node: Dump types, Next: Dump examples, Prev: Dump output verbosity, Up: Optimization info - -9.7.5 Dump types ----------------- - -'dump_printf' - - This is a generic method for doing formatted output. It takes an - additional argument 'dump_kind' which signifies the type of dump. - This method outputs information only when the dumps are enabled for - this particular 'dump_kind'. Note that the caller doesn't need to - know if the particular dump is enabled or not, or even the file - name. The caller only needs to decide which dump output - information is relevant, and under what conditions. This - determines the associated flags. - - Consider the following example from 'loop-unroll.c' where an - informative message about a loop (along with its location) is - printed when any of the following flags is enabled - - - optimization messages - - RTL dumps - - detailed dumps - - int report_flags = MSG_OPTIMIZED_LOCATIONS | TDF_RTL | TDF_DETAILS; - dump_printf_loc (report_flags, locus, - "loop turned into non-loop; it never loops.\n"); - -'dump_basic_block' - Output basic block. -'dump_generic_expr' - Output generic expression. -'dump_gimple_stmt' - Output gimple statement. - - Note that the above methods also have variants prefixed with - '_loc', such as 'dump_printf_loc', which are similar except they - also output the source location information. - - -File: gccint.info, Node: Dump examples, Prev: Dump types, Up: Optimization info - -9.7.6 Dump examples -------------------- - - gcc -O3 -fopt-info-missed=missed.all - - outputs missed optimization report from all the passes into -'missed.all'. - - As another example, - gcc -O3 -fopt-info-inline-optimized-missed=inline.txt - - will output information about missed optimizations as well as optimized -locations from all the inlining passes into 'inline.txt'. - - If the FILENAME is provided, then the dumps from all the applicable -optimizations are concatenated into the 'filename'. Otherwise the dump -is output onto 'stderr'. If OPTIONS is omitted, it defaults to -'all-all', which means dump all available optimization info from all the -passes. In the following example, all optimization info is output on to -'stderr'. - - gcc -O3 -fopt-info - - Note that '-fopt-info-vec-missed' behaves the same as -'-fopt-info-missed-vec'. - - As another example, consider - - gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt - - Here the two output file names 'vec.miss' and 'loop.opt' are in -conflict since only one output file is allowed. In this case, only the -first option takes effect and the subsequent options are ignored. Thus -only the 'vec.miss' is produced which containts dumps from the -vectorizer about missed opportunities. - - -File: gccint.info, Node: GENERIC, Next: GIMPLE, Prev: Passes, Up: Top - -10 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 almost -everything was already there. If you can express it with the codes in -'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 'TREE_SIDE_EFFECTS' set (or it will be discarded), but a -non-statement expression may also have side effects. A '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 -'tree_rest_of_compilation', but this seems inelegant. - -* Menu: - -* Deficiencies:: Topics net yet covered in this document. -* Tree overview:: All about 'tree's. -* Types:: Fundamental and aggregate types. -* Declarations:: Type declarations and variables. -* Attributes:: Declaration and type attributes. -* Expressions: Expression trees. Operating on data. -* Statements:: Control flow and related trees. -* Functions:: Function bodies, linkage, and other aspects. -* Language-dependent trees:: Topics and trees specific to language front ends. -* C and C++ Trees:: Trees specific to C and C++. -* Java Trees:: Trees specific to Java. - - -File: gccint.info, Node: Deficiencies, Next: Tree overview, Up: GENERIC - -10.1 Deficiencies -================= - -There are many places in which this document is incomplet and incorrekt. -It is, as of yet, only _preliminary_ documentation. - - -File: gccint.info, Node: Tree overview, Next: Types, Prev: Deficiencies, Up: GENERIC - -10.2 Overview -============= - -The central data structure used by the internal representation is the -'tree'. These nodes, while all of the C type 'tree', are of many -varieties. A '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 'this font', except when -talking about the actual C type 'tree'. - - You can tell what kind of node a particular tree is by using the -'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 '--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 '_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 '0', so that statements like - if (TEST_P (t) && !TEST_P (y)) - x = 1; -and - int i = (TEST_P (t) != 0); -are legal. Macros that return 'int' values now may be changed to return -'tree' values, or other pointers in the future. Even those that -continue to return 'int' may return multiple nonzero codes where -previously they returned only zero and one. Therefore, you should not -write code like - if (TEST_P (t) == 1) -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 'error_mark_node' is a special tree. Its tree code is -'ERROR_MARK', but since there is only ever one node with that code, the -usual practice is to compare the tree against 'error_mark_node'. (This -test is just a test for pointer equality.) If an error has occurred -during front-end processing the flag 'errorcount' will be set. If the -front end has encountered code it cannot handle, it will issue a message -to the user and set 'sorrycount'. When these flags are set, any macro -or function which normally returns a tree of a particular kind may -instead return the 'error_mark_node'. Thus, if you intend to do any -processing of erroneous code, you must be prepared to deal with the -'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. - - -File: gccint.info, Node: Macros and Functions, Next: Identifiers, Up: Tree overview - -10.2.1 Trees ------------- - -All GENERIC trees have two fields in common. First, 'TREE_CHAIN' is a -pointer that can be used as a singly-linked list to other trees. The -other is 'TREE_TYPE'. Many trees store the type of an expression or -declaration in this field. - - These are some other functions for handling trees: - -'tree_size' - Return the number of bytes a tree takes. - -'build0' -'build1' -'build2' -'build3' -'build4' -'build5' -'build6' - - These functions build a tree and supply values to put in each - parameter. The basic signature is 'code, type, [operands]'. - 'code' is the 'TREE_CODE', and 'type' is a tree representing the - 'TREE_TYPE'. These are followed by the operands, each of which is - also a tree. - - -File: gccint.info, Node: Identifiers, Next: Containers, Prev: Macros and Functions, Up: Tree overview - -10.2.2 Identifiers ------------------- - -An 'IDENTIFIER_NODE' represents a slightly more general concept than the -standard C or C++ concept of identifier. In particular, an -'IDENTIFIER_NODE' may contain a '$', or other extraordinary characters. - - There are never two distinct 'IDENTIFIER_NODE's representing the same -identifier. Therefore, you may use pointer equality to compare -'IDENTIFIER_NODE's, rather than using a routine like 'strcmp'. Use -'get_identifier' to obtain the unique 'IDENTIFIER_NODE' for a supplied -string. - - You can use the following macros to access identifiers: -'IDENTIFIER_POINTER' - The string represented by the identifier, represented as a 'char*'. - This string is always 'NUL'-terminated, and contains no embedded - 'NUL' characters. - -'IDENTIFIER_LENGTH' - The length of the string returned by 'IDENTIFIER_POINTER', not - including the trailing 'NUL'. This value of 'IDENTIFIER_LENGTH - (x)' is always the same as 'strlen (IDENTIFIER_POINTER (x))'. - -'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 'IDENTIFIER_POINTER' or the - 'IDENTIFIER_LENGTH'. - -'IDENTIFIER_TYPENAME_P' - This predicate holds if the identifier represents the name of a - user-defined conversion operator. In this case, the 'TREE_TYPE' of - the 'IDENTIFIER_NODE' holds the type to which the conversion - operator converts. - - -File: gccint.info, Node: Containers, Prev: Identifiers, Up: Tree overview - -10.2.3 Containers ------------------ - -Two common container data structures can be represented directly with -tree nodes. A 'TREE_LIST' is a singly linked list containing two trees -per node. These are the 'TREE_PURPOSE' and 'TREE_VALUE' of each node. -(Often, the 'TREE_PURPOSE' contains some kind of tag, or additional -information, while the 'TREE_VALUE' contains the majority of the -payload. In other cases, the 'TREE_PURPOSE' is simply 'NULL_TREE', -while in still others both the 'TREE_PURPOSE' and 'TREE_VALUE' are of -equal stature.) Given one 'TREE_LIST' node, the next node is found by -following the 'TREE_CHAIN'. If the 'TREE_CHAIN' is 'NULL_TREE', then -you have reached the end of the list. - - A 'TREE_VEC' is a simple vector. The 'TREE_VEC_LENGTH' is an integer -(not a tree) giving the number of nodes in the vector. The nodes -themselves are accessed using the 'TREE_VEC_ELT' macro, which takes two -arguments. The first is the 'TREE_VEC' in question; the second is an -integer indicating which element in the vector is desired. The elements -are indexed from zero. - - -File: gccint.info, Node: Types, Next: Declarations, Prev: Tree overview, Up: GENERIC - -10.3 Types -========== - -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 multiple nodes corresponding to the same type. - - For the most part, different kinds of types have different tree codes. -(For example, pointer types use a 'POINTER_TYPE' code while arrays use -an 'ARRAY_TYPE' code.) However, pointers to member functions use the -'RECORD_TYPE' code. Therefore, when writing a 'switch' statement that -depends on the code associated with a particular type, you should take -care to handle pointers to member functions under the 'RECORD_TYPE' case -label. - - The following functions and macros deal with cv-qualification of types: -'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. - - A few other macros and functions are usable with all types: -'TYPE_SIZE' - The number of bits required to represent the type, represented as - an 'INTEGER_CST'. For an incomplete type, 'TYPE_SIZE' will be - 'NULL_TREE'. - -'TYPE_ALIGN' - The alignment of the type, in bits, represented as an 'int'. - -'TYPE_NAME' - This macro returns a declaration (in the form of a 'TYPE_DECL') for - the type. (Note this macro does _not_ return an 'IDENTIFIER_NODE', - as you might expect, given its name!) You can look at the - 'DECL_NAME' of the 'TYPE_DECL' to obtain the actual name of the - type. The 'TYPE_NAME' will be 'NULL_TREE' for a type that is not a - built-in type, the result of a typedef, or a named class type. - -'TYPE_CANONICAL' - This macro returns the "canonical" type for the given type node. - Canonical types are used to improve performance in the C++ and - Objective-C++ front ends by allowing efficient comparison between - two type nodes in 'same_type_p': if the 'TYPE_CANONICAL' values of - the types are equal, the types are equivalent; otherwise, the types - are not equivalent. The notion of equivalence for canonical types - is the same as the notion of type equivalence in the language - itself. For instance, - - When 'TYPE_CANONICAL' is 'NULL_TREE', there is no canonical type - for the given type node. In this case, comparison between this - type and any other type requires the compiler to perform a deep, - "structural" comparison to see if the two type nodes have the same - form and properties. - - The canonical type for a node is always the most fundamental type - in the equivalence class of types. For instance, 'int' is its own - canonical type. A typedef 'I' of 'int' will have 'int' as its - canonical type. Similarly, 'I*' and a typedef 'IP' (defined to - 'I*') will has 'int*' as their canonical type. When building a new - type node, be sure to set 'TYPE_CANONICAL' to the appropriate - canonical type. If the new type is a compound type (built from - other types), and any of those other types require structural - equality, use 'SET_TYPE_STRUCTURAL_EQUALITY' to ensure that the new - type also requires structural equality. Finally, if for some - reason you cannot guarantee that 'TYPE_CANONICAL' will point to the - canonical type, use 'SET_TYPE_STRUCTURAL_EQUALITY' to make sure - that the new type-and any type constructed based on it-requires - structural equality. If you suspect that the canonical type system - is miscomparing types, pass '--param verify-canonical-types=1' to - the compiler or configure with '--enable-checking' to force the - compiler to verify its canonical-type comparisons against the - structural comparisons; the compiler will then print any warnings - if the canonical types miscompare. - -'TYPE_STRUCTURAL_EQUALITY_P' - This predicate holds when the node requires structural equality - checks, e.g., when 'TYPE_CANONICAL' is 'NULL_TREE'. - -'SET_TYPE_STRUCTURAL_EQUALITY' - This macro states that the type node it is given requires - structural equality checks, e.g., it sets 'TYPE_CANONICAL' to - 'NULL_TREE'. - -'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 'typedef' for the other, - or both are '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 '==' (pointer equality) to - compare types; always use 'same_type_p' instead. - - 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. - -'VOID_TYPE' - Used to represent the 'void' type. - -'INTEGER_TYPE' - Used to represent the various integral types, including 'char', - 'short', 'int', 'long', and 'long long'. This code is not used for - enumeration types, nor for the 'bool' type. The 'TYPE_PRECISION' - is the number of bits used in the representation, represented as an - 'unsigned int'. (Note that in the general case this is not the - same value as 'TYPE_SIZE'; suppose that there were a 24-bit integer - type, but that alignment requirements for the ABI required 32-bit - alignment. Then, 'TYPE_SIZE' would be an 'INTEGER_CST' for 32, - while 'TYPE_PRECISION' would be 24.) The integer type is unsigned - if 'TYPE_UNSIGNED' holds; otherwise, it is signed. - - The 'TYPE_MIN_VALUE' is an 'INTEGER_CST' for the smallest integer - that may be represented by this type. Similarly, the - 'TYPE_MAX_VALUE' is an 'INTEGER_CST' for the largest integer that - may be represented by this type. - -'REAL_TYPE' - Used to represent the 'float', 'double', and 'long double' types. - The number of bits in the floating-point representation is given by - 'TYPE_PRECISION', as in the 'INTEGER_TYPE' case. - -'FIXED_POINT_TYPE' - Used to represent the 'short _Fract', '_Fract', 'long _Fract', - 'long long _Fract', 'short _Accum', '_Accum', 'long _Accum', and - 'long long _Accum' types. The number of bits in the fixed-point - representation is given by 'TYPE_PRECISION', as in the - 'INTEGER_TYPE' case. There may be padding bits, fractional bits - and integral bits. The number of fractional bits is given by - 'TYPE_FBIT', and the number of integral bits is given by - 'TYPE_IBIT'. The fixed-point type is unsigned if 'TYPE_UNSIGNED' - holds; otherwise, it is signed. The fixed-point type is saturating - if 'TYPE_SATURATING' holds; otherwise, it is not saturating. - -'COMPLEX_TYPE' - Used to represent GCC built-in '__complex__' data types. The - 'TREE_TYPE' is the type of the real and imaginary parts. - -'ENUMERAL_TYPE' - Used to represent an enumeration type. The 'TYPE_PRECISION' gives - (as an 'int'), the number of bits used to represent the type. If - there are no negative enumeration constants, 'TYPE_UNSIGNED' will - hold. The minimum and maximum enumeration constants may be - obtained with 'TYPE_MIN_VALUE' and 'TYPE_MAX_VALUE', respectively; - each of these macros returns an 'INTEGER_CST'. - - The actual enumeration constants themselves may be obtained by - looking at the 'TYPE_VALUES'. This macro will return a - 'TREE_LIST', containing the constants. The 'TREE_PURPOSE' of each - node will be an 'IDENTIFIER_NODE' giving the name of the constant; - the 'TREE_VALUE' will be an 'INTEGER_CST' giving the value assigned - to that constant. These constants will appear in the order in - which they were declared. The 'TREE_TYPE' of each of these - constants will be the type of enumeration type itself. - -'BOOLEAN_TYPE' - Used to represent the 'bool' type. - -'POINTER_TYPE' - Used to represent pointer types, and pointer to data member types. - The 'TREE_TYPE' gives the type to which this type points. - -'REFERENCE_TYPE' - Used to represent reference types. The 'TREE_TYPE' gives the type - to which this type refers. - -'FUNCTION_TYPE' - Used to represent the type of non-member functions and of static - member functions. The 'TREE_TYPE' gives the return type of the - function. The 'TYPE_ARG_TYPES' are a 'TREE_LIST' of the argument - types. The 'TREE_VALUE' of each node in this list is the type of - the corresponding argument; the 'TREE_PURPOSE' is an expression for - the default argument value, if any. If the last node in the list - is 'void_list_node' (a 'TREE_LIST' node whose 'TREE_VALUE' is the - '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 'void f()' - is an unprototyped function taking a variable number of arguments; - the 'TYPE_ARG_TYPES' of such a function will be 'NULL'. - -'METHOD_TYPE' - Used to represent the type of a non-static member function. Like a - 'FUNCTION_TYPE', the return type is given by the 'TREE_TYPE'. The - type of '*this', i.e., the class of which functions of this type - are a member, is given by the 'TYPE_METHOD_BASETYPE'. The - 'TYPE_ARG_TYPES' is the parameter list, as for a 'FUNCTION_TYPE', - and includes the 'this' argument. - -'ARRAY_TYPE' - Used to represent array types. The 'TREE_TYPE' gives the type of - the elements in the array. If the array-bound is present in the - type, the 'TYPE_DOMAIN' is an 'INTEGER_TYPE' whose 'TYPE_MIN_VALUE' - and 'TYPE_MAX_VALUE' will be the lower and upper bounds of the - array, respectively. The 'TYPE_MIN_VALUE' will always be an - 'INTEGER_CST' for zero, while the '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. - -'RECORD_TYPE' - Used to represent 'struct' and 'class' types, as well as pointers - to member functions and similar constructs in other languages. - 'TYPE_FIELDS' contains the items contained in this type, each of - which can be a 'FIELD_DECL', 'VAR_DECL', 'CONST_DECL', or - '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. - -'UNION_TYPE' - Used to represent 'union' types. Similar to 'RECORD_TYPE' except - that all 'FIELD_DECL' nodes in 'TYPE_FIELD' start at bit position - zero. - -'QUAL_UNION_TYPE' - Used to represent part of a variant record in Ada. Similar to - 'UNION_TYPE' except that each 'FIELD_DECL' has a '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 'DECL_QUALIFIER' is only evaluated if none - of the expressions in the previous fields in 'TYPE_FIELDS' are - nonzero. Normally these expressions will reference a field in the - outer object using a 'PLACEHOLDER_EXPR'. - -'LANG_TYPE' - This node is used to represent a language-specific type. The front - end must handle it. - -'OFFSET_TYPE' - This node is used to represent a pointer-to-data member. For a - data member 'X::m' the 'TYPE_OFFSET_BASETYPE' is 'X' and the - 'TREE_TYPE' is the type of 'm'. - - There are variables whose values represent some of the basic types. -These include: -'void_type_node' - A node for 'void'. - -'integer_type_node' - A node for 'int'. - -'unsigned_type_node.' - A node for 'unsigned int'. - -'char_type_node.' - A node for 'char'. -It may sometimes be useful to compare one of these variables with a type -in hand, using 'same_type_p'. - - -File: gccint.info, Node: Declarations, Next: Attributes, Prev: Types, Up: GENERIC - -10.4 Declarations -================= - -This section covers the various kinds of declarations that appear in the -internal representation, except for declarations of functions -(represented by 'FUNCTION_DECL' nodes), which are described in *note -Functions::. - -* Menu: - -* Working with declarations:: Macros and functions that work on -declarations. -* Internal structure:: How declaration nodes are represented. - - -File: gccint.info, Node: Working with declarations, Next: Internal structure, Up: Declarations - -10.4.1 Working with declarations --------------------------------- - -Some macros can be used with any kind of declaration. These include: -'DECL_NAME' - This macro returns an 'IDENTIFIER_NODE' giving the name of the - entity. - -'TREE_TYPE' - This macro returns the type of the entity declared. - -'EXPR_FILENAME' - This macro returns the name of the file in which the entity was - declared, as a 'char*'. For an entity declared implicitly by the - compiler (like '__builtin_memcpy'), this will be the string - '"<internal>"'. - -'EXPR_LINENO' - This macro returns the line number at which the entity was - declared, as an 'int'. - -'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 'TYPE_DECL' - implicitly generated for a class type. Recall that in C++ code - like: - struct S {}; - is roughly equivalent to C code like: - struct S {}; - typedef struct S S; - The implicitly generated 'typedef' declaration is represented by a - 'TYPE_DECL' for which 'DECL_ARTIFICIAL' holds. - - The various kinds of declarations include: -'LABEL_DECL' - These nodes are used to represent labels in function bodies. For - more information, see *note Functions::. These nodes only appear - in block scopes. - -'CONST_DECL' - These nodes are used to represent enumeration constants. The value - of the constant is given by 'DECL_INITIAL' which will be an - 'INTEGER_CST' with the same type as the 'TREE_TYPE' of the - 'CONST_DECL', i.e., an 'ENUMERAL_TYPE'. - -'RESULT_DECL' - These nodes represent the value returned by a function. When a - value is assigned to a 'RESULT_DECL', that indicates that the value - should be returned, via bitwise copy, by the function. You can use - 'DECL_SIZE' and 'DECL_ALIGN' on a 'RESULT_DECL', just as with a - 'VAR_DECL'. - -'TYPE_DECL' - These nodes represent 'typedef' declarations. The 'TREE_TYPE' is - the type declared to have the name given by 'DECL_NAME'. In some - cases, there is no associated name. - -'VAR_DECL' - These nodes represent variables with namespace or block scope, as - well as static data members. The 'DECL_SIZE' and 'DECL_ALIGN' are - analogous to 'TYPE_SIZE' and 'TYPE_ALIGN'. For a declaration, you - should always use the 'DECL_SIZE' and 'DECL_ALIGN' rather than the - 'TYPE_SIZE' and 'TYPE_ALIGN' given by the '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 - 'DECL_THIS_STATIC' or 'DECL_THIS_EXTERN' to test whether the - storage class specifiers 'static' or 'extern' were used to declare - a variable. - - If this variable is initialized (but does not require a - constructor), the 'DECL_INITIAL' will be an expression for the - initializer. The initializer should be evaluated, and a bitwise - copy into the variable performed. If the 'DECL_INITIAL' is the - '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 'VAR_DECL' if - 'DECL_REGISTER' holds for the 'VAR_DECL', and if - 'DECL_ASSEMBLER_NAME' is not equal to 'DECL_NAME'. In that case, - 'DECL_ASSEMBLER_NAME' is the name of the register into which the - variable will be placed. - -'PARM_DECL' - Used to represent a parameter to a function. Treat these nodes - similarly to 'VAR_DECL' nodes. These nodes only appear in the - 'DECL_ARGUMENTS' for a 'FUNCTION_DECL'. - - The 'DECL_ARG_TYPE' for a '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 'TREE_TYPE' of the parameter; for example, - the ordinary type might be 'short' while the 'DECL_ARG_TYPE' is - 'int'. - -'DEBUG_EXPR_DECL' - Used to represent an anonymous debug-information temporary created - to hold an expression as it is optimized away, so that its value - can be referenced in debug bind statements. - -'FIELD_DECL' - These nodes represent non-static data members. The 'DECL_SIZE' and - 'DECL_ALIGN' behave as for 'VAR_DECL' nodes. The position of the - field within the parent record is specified by a combination of - three attributes. 'DECL_FIELD_OFFSET' is the position, counting in - bytes, of the 'DECL_OFFSET_ALIGN'-bit sized word containing the bit - of the field closest to the beginning of the structure. - '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 'DECL_OFFSET_ALIGN' may be greater than - the natural alignment of the field's type. - - If 'DECL_C_BIT_FIELD' holds, this field is a bit-field. In a - bit-field, '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. - -'NAMESPACE_DECL' - Namespaces provide a name hierarchy for other declarations. They - appear in the 'DECL_CONTEXT' of other '_DECL' nodes. - - -File: gccint.info, Node: Internal structure, Prev: Working with declarations, Up: Declarations - -10.4.2 Internal structure -------------------------- - -'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. - - -File: gccint.info, Node: Current structure hierarchy, Next: Adding new DECL node types, Up: Internal structure - -10.4.2.1 Current structure hierarchy -.................................... - -'struct tree_decl_minimal' - This is the minimal structure to inherit from in order for common - 'DECL' macros to work. The fields it contains are a unique ID, - source location, context, and name. - -'struct tree_decl_common' - This structure inherits from 'struct tree_decl_minimal'. It - contains fields that most 'DECL' nodes need, such as a field to - store alignment, machine mode, size, and attributes. - -'struct tree_field_decl' - This structure inherits from 'struct tree_decl_common'. It is used - to represent 'FIELD_DECL'. - -'struct tree_label_decl' - This structure inherits from 'struct tree_decl_common'. It is used - to represent 'LABEL_DECL'. - -'struct tree_translation_unit_decl' - This structure inherits from 'struct tree_decl_common'. It is used - to represent 'TRANSLATION_UNIT_DECL'. - -'struct tree_decl_with_rtl' - This structure inherits from 'struct tree_decl_common'. It - contains a field to store the low-level RTL associated with a - 'DECL' node. - -'struct tree_result_decl' - This structure inherits from 'struct tree_decl_with_rtl'. It is - used to represent 'RESULT_DECL'. - -'struct tree_const_decl' - This structure inherits from 'struct tree_decl_with_rtl'. It is - used to represent 'CONST_DECL'. - -'struct tree_parm_decl' - This structure inherits from 'struct tree_decl_with_rtl'. It is - used to represent 'PARM_DECL'. - -'struct tree_decl_with_vis' - This structure inherits from 'struct tree_decl_with_rtl'. It - contains fields necessary to store visibility information, as well - as a section name and assembler name. - -'struct tree_var_decl' - This structure inherits from 'struct tree_decl_with_vis'. It is - used to represent 'VAR_DECL'. - -'struct tree_function_decl' - This structure inherits from 'struct tree_decl_with_vis'. It is - used to represent 'FUNCTION_DECL'. - - -File: gccint.info, Node: Adding new DECL node types, Prev: Current structure hierarchy, Up: Internal structure - -10.4.2.2 Adding new DECL node types -................................... - -Adding a new 'DECL' tree consists of the following steps - -Add a new tree code for the 'DECL' node - For language specific 'DECL' nodes, there is a '.def' file in each - frontend directory where the tree code should be added. For 'DECL' - nodes that are part of the middle-end, the code should be added to - 'tree.def'. - -Create a new structure type for the 'DECL' node - These structures should inherit from one of the existing structures - in the language hierarchy by using that structure as the first - member. - - struct tree_foo_decl - { - struct tree_decl_with_vis common; - } - - Would create a structure name 'tree_foo_decl' that inherits from - 'struct tree_decl_with_vis'. - - For language specific 'DECL' nodes, this new structure type should - go in the appropriate '.h' file. For 'DECL' nodes that are part of - the middle-end, the structure type should go in 'tree.h'. - -Add a member to the tree structure enumerator for the node - For garbage collection and dynamic checking purposes, each 'DECL' - node structure type is required to have a unique enumerator value - specified with it. For language specific 'DECL' nodes, this new - enumerator value should go in the appropriate '.def' file. For - 'DECL' nodes that are part of the middle-end, the enumerator values - are specified in 'treestruct.def'. - -Update 'union tree_node' - In order to make your new structure type usable, it must be added - to 'union tree_node'. For language specific 'DECL' nodes, a new - entry should be added to the appropriate '.h' file of the form - struct tree_foo_decl GTY ((tag ("TS_VAR_DECL"))) foo_decl; - For 'DECL' nodes that are part of the middle-end, the additional - member goes directly into 'union tree_node' in 'tree.h'. - -Update dynamic checking info - In order to be able to check whether accessing a named portion of - 'union tree_node' is legal, and whether a certain 'DECL' node - contains one of the enumerated '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 'DECL' nodes, their is an 'init_ts' function - in an appropriate '.c' file, which initializes the lookup table. - Code setting up the table for new 'DECL' nodes should be added - there. For each '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 'FOO_DECL' node derived from 'struct - decl_with_rtl', and enumerator value 'TS_FOO_DECL', would be set up - as follows - 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; - - For 'DECL' nodes that are part of the middle-end, the setup code - goes into 'tree.c'. - -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 'DECL' nodes access the field. - - These macros generally take the following form - #define FOO_DECL_FIELDNAME(NODE) FOO_DECL_CHECK(NODE)->foo_decl.fieldname - However, if the structure is simply a base class for further - structures, something like the following should be used - #define BASE_STRUCT_CHECK(T) CONTAINS_STRUCT_CHECK(T, TS_BASE_STRUCT) - #define BASE_STRUCT_FIELDNAME(NODE) \ - (BASE_STRUCT_CHECK(NODE)->base_struct.fieldname - - Reading them from the generated 'all-tree.def' file (which in turn - includes all the 'tree.def' files), 'gencheck.c' is used during - GCC's build to generate the '*_CHECK' macros for all tree codes. - - -File: gccint.info, Node: Attributes, Next: Expression trees, Prev: Declarations, Up: GENERIC - -10.5 Attributes in trees -======================== - -Attributes, as specified using the '__attribute__' keyword, are -represented internally as a 'TREE_LIST'. The 'TREE_PURPOSE' is the name -of the attribute, as an 'IDENTIFIER_NODE'. The 'TREE_VALUE' is a -'TREE_LIST' of the arguments of the attribute, if any, or 'NULL_TREE' if -there are no arguments; the arguments are stored as the 'TREE_VALUE' of -successive entries in the list, and may be identifiers or expressions. -The 'TREE_CHAIN' of the attribute is the next attribute in a list of -attributes applying to the same declaration or type, or '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. - - -- Tree Macro: tree DECL_ATTRIBUTES (tree DECL) - This macro returns the attributes on the declaration DECL. - - -- Tree Macro: tree TYPE_ATTRIBUTES (tree TYPE) - This macro returns the attributes on the type TYPE. - - -File: gccint.info, Node: Expression trees, Next: Statements, Prev: Attributes, Up: GENERIC - -10.6 Expressions -================ - -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 you rely on certain kinds -of nodes being unshared. - - The following macros can be used with all expression nodes: - -'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. - - In what follows, some nodes that one might expect to always have type -'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 -'TREE_OPERAND' macro. For example, to access the first operand to a -binary plus expression 'expr', use: - - TREE_OPERAND (expr, 0) - - As this example indicates, the operands are zero-indexed. - -* Menu: - -* Constants: Constant expressions. -* Storage References:: -* Unary and Binary Expressions:: -* Vectors:: - - -File: gccint.info, Node: Constant expressions, Next: Storage References, Up: Expression trees - -10.6.1 Constant expressions ---------------------------- - -The table below begins with constants, moves on to unary expressions, -then proceeds to binary expressions, and concludes with various other -kinds of expressions: - -'INTEGER_CST' - These nodes represent integer constants. Note that the type of - these constants is obtained with 'TREE_TYPE'; they are not always - of type 'int'. In particular, 'char' constants are represented - with 'INTEGER_CST' nodes. The value of the integer constant 'e' is - given by - ((TREE_INT_CST_HIGH (e) << HOST_BITS_PER_WIDE_INT) - + TREE_INST_CST_LOW (e)) - HOST_BITS_PER_WIDE_INT is at least thirty-two on all platforms. - Both 'TREE_INT_CST_HIGH' and 'TREE_INT_CST_LOW' return a - 'HOST_WIDE_INT'. The value of an '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 'integer_zero_node' is an integer constant with value - zero. Similarly, 'integer_one_node' is an integer constant with - value one. The 'size_zero_node' and 'size_one_node' variables are - analogous, but have type 'size_t' rather than 'int'. - - The function '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, 'tree_int_cst_equal' holds if - the two constants are equal. The 'tree_int_cst_sgn' function - returns the sign of a constant. The value is '1', '0', or '-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. - -'REAL_CST' - - FIXME: Talk about how to obtain representations of this constant, - do comparisons, and so forth. - -'FIXED_CST' - - These nodes represent fixed-point constants. The type of these - constants is obtained with 'TREE_TYPE'. 'TREE_FIXED_CST_PTR' - points to a 'struct fixed_value'; 'TREE_FIXED_CST' returns the - structure itself. 'struct fixed_value' contains 'data' with the - size of two 'HOST_BITS_PER_WIDE_INT' and 'mode' as the associated - fixed-point machine mode for 'data'. - -'COMPLEX_CST' - These nodes are used to represent complex number constants, that is - a '__complex__' whose parts are constant nodes. The - 'TREE_REALPART' and 'TREE_IMAGPART' return the real and the - imaginary parts respectively. - -'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 'TREE_LIST' of - the constant nodes and is accessed through 'TREE_VECTOR_CST_ELTS'. - -'STRING_CST' - These nodes represent string-constants. The 'TREE_STRING_LENGTH' - returns the length of the string, as an 'int'. The - 'TREE_STRING_POINTER' is a 'char*' containing the string itself. - The string may not be 'NUL'-terminated, and it may contain embedded - 'NUL' characters. Therefore, the 'TREE_STRING_LENGTH' includes the - trailing 'NUL' if it is present. - - For wide string constants, the 'TREE_STRING_LENGTH' is the number - of bytes in the string, and the '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 'TREE_TYPE' - of the '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. - - -File: gccint.info, Node: Storage References, Next: Unary and Binary Expressions, Prev: Constant expressions, Up: Expression trees - -10.6.2 References to storage ----------------------------- - -'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 - 'array_ref_low_bound' and 'array_ref_element_size' instead. - -'ARRAY_RANGE_REF' - These nodes represent access to a range (or "slice") of an array. - The operands are the same as that for '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. - -'TARGET_MEM_REF' - These nodes represent memory accesses whose address directly map to - an addressing mode of the target architecture. The first argument - is 'TMR_SYMBOL' and must be a 'VAR_DECL' of an object with a fixed - address. The second argument is 'TMR_BASE' and the third one is - 'TMR_INDEX'. The fourth argument is 'TMR_STEP' and must be an - 'INTEGER_CST'. The fifth argument is 'TMR_OFFSET' and must be an - 'INTEGER_CST'. Any of the arguments may be NULL if the appropriate - component does not appear in the address. Address of the - 'TARGET_MEM_REF' is determined in the following way. - - &TMR_SYMBOL + TMR_BASE + TMR_INDEX * TMR_STEP + TMR_OFFSET - - 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. - -'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 'ADDR_EXPR' will be a - 'LABEL_DECL'. The type of such an expression is 'void*'. - - If the object addressed is not an lvalue, a temporary is created, - and the address of the temporary is used. - -'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. - -'MEM_REF' - These nodes are used to represent the object pointed to by a - pointer offset by a constant. The first operand is the pointer - being dereferenced; it will always have pointer or reference type. - The second operand is a pointer constant. Its type is specifying - the type to be used for type-based alias analysis. - -'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 'FIELD_DECL' for the data member. The third operand - represents the byte offset of the field, but should not be used - directly; call 'component_ref_field_offset' instead. - - -File: gccint.info, Node: Unary and Binary Expressions, Next: Vectors, Prev: Storage References, Up: Expression trees - -10.6.3 Unary and Binary Expressions ------------------------------------ - -'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 'flag_wrapv' and 'flag_trapv' variables. - -'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 'abs', 'labs' and 'llabs' builtins for integer types, - and the 'fabs', 'fabsf' and '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 'BUILT_IN_CABS', - 'BUILT_IN_CABSF' or 'BUILT_IN_CABSL' builtins, as used to implement - the C99 'cabs', 'cabsf' and 'cabsl' built-in functions. - -'BIT_NOT_EXPR' - These nodes represent bitwise complement, and will always have - integral type. The only operand is the value to be complemented. - -'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 'BOOLEAN_TYPE' or 'INTEGER_TYPE'. - -'PREDECREMENT_EXPR' -'PREINCREMENT_EXPR' -'POSTDECREMENT_EXPR' -'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 'PREDECREMENT_EXPR' and - 'PREINCREMENT_EXPR', the value of the expression is the value - resulting after the increment or decrement; in the case of - 'POSTDECREMENT_EXPR' and '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. - -'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. - -'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 '-mieee'? - -'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. - -'CONJ_EXPR' - These nodes represent the conjugate of their operand. - -'REALPART_EXPR' -'IMAGPART_EXPR' - These nodes represent respectively the real and the imaginary parts - of complex numbers (their sole argument). - -'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. - -'NOP_EXPR' - These nodes are used to represent conversions that do not require - any code-generation. For example, conversion of a 'char*' to an - 'int*' does not require any code be generated; such a conversion is - represented by a 'NOP_EXPR'. The single operand is the expression - to be converted. The conversion from a pointer to a reference is - also represented with a 'NOP_EXPR'. - -'CONVERT_EXPR' - These nodes are similar to 'NOP_EXPR's, but are used in those - situations where code may need to be generated. For example, if an - 'int*' is converted to an '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 'CONVERT_EXPR'; - instead, the function calls are made explicit. - -'FIXED_CONVERT_EXPR' - These nodes are used to represent conversions that involve - fixed-point values. For example, from a fixed-point value to - another fixed-point value, from an integer to a fixed-point value, - from a fixed-point value to an integer, from a floating-point value - to a fixed-point value, or from a fixed-point value to a - floating-point value. - -'LSHIFT_EXPR' -'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. - Unlike most nodes, these can have a vector as first operand and a - scalar as second operand. - -'BIT_IOR_EXPR' -'BIT_XOR_EXPR' -'BIT_AND_EXPR' - These nodes represent bitwise inclusive or, bitwise exclusive or, - and bitwise and, respectively. Both operands will always have - integral type. - -'TRUTH_ANDIF_EXPR' -'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 'BOOLEAN_TYPE' or 'INTEGER_TYPE'. - -'TRUTH_AND_EXPR' -'TRUTH_OR_EXPR' -'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 'BOOLEAN_TYPE' or - 'INTEGER_TYPE'. - -'POINTER_PLUS_EXPR' - This node represents pointer arithmetic. The first operand is - always a pointer/reference type. The second operand is always an - unsigned integer type compatible with sizetype. This is the only - binary arithmetic operand that can operate on pointer types. - -'PLUS_EXPR' -'MINUS_EXPR' -'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 'flag_wrapv' and 'flag_trapv' variables. - -'MULT_HIGHPART_EXPR' - This node represents the "high-part" of a widening multiplication. - For an integral type with B bits of precision, the result is the - most significant B bits of the full 2B product. - -'RDIV_EXPR' - This node represents a floating point division operation. - -'TRUNC_DIV_EXPR' -'FLOOR_DIV_EXPR' -'CEIL_DIV_EXPR' -'ROUND_DIV_EXPR' - These nodes represent integer division operations that return an - integer result. 'TRUNC_DIV_EXPR' rounds towards zero, - 'FLOOR_DIV_EXPR' rounds towards negative infinity, 'CEIL_DIV_EXPR' - rounds towards positive infinity and 'ROUND_DIV_EXPR' rounds to the - closest integer. Integer division in C and C++ is truncating, i.e. - '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 'flag_wrapv' and 'flag_trapv' variables. - -'TRUNC_MOD_EXPR' -'FLOOR_MOD_EXPR' -'CEIL_MOD_EXPR' -'ROUND_MOD_EXPR' - These nodes represent the integer remainder or modulus operation. - The integer modulus of two operands 'a' and 'b' is defined as 'a - - (a/b)*b' where the division calculated using the corresponding - division operator. Hence for 'TRUNC_MOD_EXPR' this definition - assumes division using truncation towards zero, i.e. - 'TRUNC_DIV_EXPR'. Integer remainder in C and C++ uses truncating - division, i.e. 'TRUNC_MOD_EXPR'. - -'EXACT_DIV_EXPR' - The '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 'TRUNC_DIV_EXPR', 'CEIL_DIV_EXPR' and 'FLOOR_DIV_EXPR' for the - current target. - -'LT_EXPR' -'LE_EXPR' -'GT_EXPR' -'GE_EXPR' -'EQ_EXPR' -'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 operands will either be both of - integral type, both of floating type or both of vector type. The - result type of these expressions will always be of integral, - boolean or signed integral vector type. These operations return - the result type's zero value for false, the result type's one value - for true, and a vector whose elements are zero (false) or minus one - (true) for vectors. - - For floating point comparisons, if we honor IEEE NaNs and either - operand is NaN, then '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. - -'ORDERED_EXPR' -'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. - -'UNLT_EXPR' -'UNLE_EXPR' -'UNGT_EXPR' -'UNGE_EXPR' -'UNEQ_EXPR' -'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, '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 '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. - -'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 'VAR_DECL', 'INDIRECT_REF', 'COMPONENT_REF', or - other lvalue. - - These nodes are used to represent not only assignment with '=' but - also compound assignments (like '+='), by reduction to '=' - assignment. In other words, the representation for 'i += 3' looks - just like that for 'i = i + 3'. - -'INIT_EXPR' - These nodes are just like '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. - -'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. - -'COND_EXPR' - These nodes represent '?:' 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 '(i >= 0 && i < 10) - ? i : abort()'. - - As a GNU extension, the C language front-ends allow the second - operand of the '?:' operator may be omitted in the source. For - example, 'x ? : 3' is equivalent to 'x ? x : 3', assuming that 'x' - is an expression without side-effects. In the tree representation, - however, the second operand is always present, possibly protected - by 'SAVE_EXPR' if the first argument does cause side-effects. - -'CALL_EXPR' - These nodes are used to represent calls to functions, including - non-static member functions. 'CALL_EXPR's are implemented as - expression nodes with a variable number of operands. Rather than - using 'TREE_OPERAND' to extract them, it is preferable to use the - specialized accessor macros and functions that operate specifically - on 'CALL_EXPR' nodes. - - 'CALL_EXPR_FN' returns a pointer to the function to call; it is - always an expression whose type is a 'POINTER_TYPE'. - - The number of arguments to the call is returned by - 'call_expr_nargs', while the arguments themselves can be accessed - with the 'CALL_EXPR_ARG' macro. The arguments are zero-indexed and - numbered left-to-right. You can iterate over the arguments using - 'FOR_EACH_CALL_EXPR_ARG', as in: - - tree call, arg; - call_expr_arg_iterator iter; - FOR_EACH_CALL_EXPR_ARG (arg, iter, call) - /* arg is bound to successive arguments of call. */ - ...; - - For non-static member functions, there will be an operand - corresponding to the '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. - - 'CALL_EXPR's also have a 'CALL_EXPR_STATIC_CHAIN' operand that is - used to implement nested functions. This operand is otherwise - null. - -'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. - -'CONSTRUCTOR' - These nodes represent the brace-enclosed initializers for a - structure or an array. They contain a sequence of component values - made out of a vector of constructor_elt, which is a ('INDEX', - 'VALUE') pair. - - If the 'TREE_TYPE' of the 'CONSTRUCTOR' is a 'RECORD_TYPE', - 'UNION_TYPE' or 'QUAL_UNION_TYPE' then the 'INDEX' of each node in - the sequence will be a 'FIELD_DECL' and the 'VALUE' will be the - expression used to initialize that field. - - If the 'TREE_TYPE' of the 'CONSTRUCTOR' is an 'ARRAY_TYPE', then - the 'INDEX' of each node in the sequence will be an 'INTEGER_CST' - or a 'RANGE_EXPR' of two 'INTEGER_CST's. A single 'INTEGER_CST' - indicates which element of the array is being assigned to. A - 'RANGE_EXPR' indicates an inclusive range of elements to - initialize. In both cases the 'VALUE' is the corresponding - initializer. It is re-evaluated for each element of a - 'RANGE_EXPR'. If the 'INDEX' is '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 cleared - (zeroed), unless the CONSTRUCTOR_NO_CLEARING flag is set, in which - case their value becomes undefined. - -'COMPOUND_LITERAL_EXPR' - These nodes represent ISO C99 compound literals. The - 'COMPOUND_LITERAL_EXPR_DECL_EXPR' is a 'DECL_EXPR' containing an - anonymous 'VAR_DECL' for the unnamed object represented by the - compound literal; the 'DECL_INITIAL' of that 'VAR_DECL' is a - 'CONSTRUCTOR' representing the brace-enclosed list of initializers - in the compound literal. That anonymous 'VAR_DECL' can also be - accessed directly by the 'COMPOUND_LITERAL_EXPR_DECL' macro. - -'SAVE_EXPR' - - A '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 'SAVE_EXPR' is the expression to evaluate. The side-effects - should be executed where the 'SAVE_EXPR' is first encountered in a - depth-first preorder traversal of the expression tree. - -'TARGET_EXPR' - A 'TARGET_EXPR' represents a temporary object. The first operand - is a '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 '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 'TARGET_EXPR' is "normal"; otherwise, we say it is - "orphaned". For a normal '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 '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 'COND_EXPR'), the cleanup must be run only if - that branch is actually executed. - -'VA_ARG_EXPR' - This node is used to implement support for the C/C++ variable - argument-list mechanism. It represents expressions like 'va_arg - (ap, type)'. Its 'TREE_TYPE' yields the tree representation for - 'type' and its sole argument yields the representation for 'ap'. - -'ANNOTATE_EXPR' - This node is used to attach markers to an expression. The first - operand is the annotated expression, the second is an 'INTEGER_CST' - with a value from 'enum annot_expr_kind'. - - -File: gccint.info, Node: Vectors, Prev: Unary and Binary Expressions, Up: Expression trees - -10.6.4 Vectors --------------- - -'VEC_LSHIFT_EXPR' -'VEC_RSHIFT_EXPR' - These nodes represent whole vector left and right shifts, - respectively. The first operand is the vector to shift; it will - always be of vector type. The second operand is an expression for - the number of bits by which to shift. Note that the result is - undefined if the second operand is larger than or equal to the - first operand's type size. - -'VEC_WIDEN_MULT_HI_EXPR' -'VEC_WIDEN_MULT_LO_EXPR' - These nodes represent widening vector multiplication of the high - and low parts of the two input vectors, respectively. Their - operands are vectors that contain the same number of elements ('N') - of the same integral type. The result is a vector that contains - half as many elements, of an integral type whose size is twice as - wide. In the case of 'VEC_WIDEN_MULT_HI_EXPR' the high 'N/2' - elements of the two vector are multiplied to produce the vector of - 'N/2' products. In the case of 'VEC_WIDEN_MULT_LO_EXPR' the low - 'N/2' elements of the two vector are multiplied to produce the - vector of 'N/2' products. - -'VEC_UNPACK_HI_EXPR' -'VEC_UNPACK_LO_EXPR' - These nodes represent unpacking of the high and low parts of the - input vector, respectively. The single operand is a vector that - contains 'N' elements of the same integral or floating point type. - The result is a vector that contains half as many elements, of an - integral or floating point type whose size is twice as wide. In - the case of 'VEC_UNPACK_HI_EXPR' the high 'N/2' elements of the - vector are extracted and widened (promoted). In the case of - 'VEC_UNPACK_LO_EXPR' the low 'N/2' elements of the vector are - extracted and widened (promoted). - -'VEC_UNPACK_FLOAT_HI_EXPR' -'VEC_UNPACK_FLOAT_LO_EXPR' - These nodes represent unpacking of the high and low parts of the - input vector, where the values are converted from fixed point to - floating point. The single operand is a vector that contains 'N' - elements of the same integral type. The result is a vector that - contains half as many elements of a floating point type whose size - is twice as wide. In the case of 'VEC_UNPACK_HI_EXPR' the high - 'N/2' elements of the vector are extracted, converted and widened. - In the case of 'VEC_UNPACK_LO_EXPR' the low 'N/2' elements of the - vector are extracted, converted and widened. - -'VEC_PACK_TRUNC_EXPR' - This node represents packing of truncated elements of the two input - vectors into the output vector. Input operands are vectors that - contain the same number of elements of the same integral or - floating point type. The result is a vector that contains twice as - many elements of an integral or floating point type whose size is - half as wide. The elements of the two vectors are demoted and - merged (concatenated) to form the output vector. - -'VEC_PACK_SAT_EXPR' - This node represents packing of elements of the two input vectors - into the output vector using saturation. Input operands are - vectors that contain the same number of elements of the same - integral type. The result is a vector that contains twice as many - elements of an integral type whose size is half as wide. The - elements of the two vectors are demoted and merged (concatenated) - to form the output vector. - -'VEC_PACK_FIX_TRUNC_EXPR' - This node represents packing of elements of the two input vectors - into the output vector, where the values are converted from - floating point to fixed point. Input operands are vectors that - contain the same number of elements of a floating point type. The - result is a vector that contains twice as many elements of an - integral type whose size is half as wide. The elements of the two - vectors are merged (concatenated) to form the output vector. - -'VEC_COND_EXPR' - These nodes represent '?:' expressions. The three operands must be - vectors of the same size and number of elements. The second and - third operands must have the same type as the entire expression. - The first operand is of signed integral vector type. If an element - of the first operand evaluates to a zero value, the corresponding - element of the result is taken from the third operand. If it - evaluates to a minus one value, it is taken from the second - operand. It should never evaluate to any other value currently, - but optimizations should not rely on that property. In contrast - with a 'COND_EXPR', all operands are always evaluated. - - -File: gccint.info, Node: Statements, Next: Functions, Prev: Expression trees, Up: GENERIC - -10.7 Statements -=============== - -Most statements in GIMPLE are assignment statements, represented by -'GIMPLE_ASSIGN'. No other C expressions can appear at statement level; -a reference to a volatile object is converted into a 'GIMPLE_ASSIGN'. - - There are also several varieties of complex statements. - -* Menu: - -* Basic Statements:: -* Blocks:: -* Statement Sequences:: -* Empty Statements:: -* Jumps:: -* Cleanups:: -* OpenMP:: - - -File: gccint.info, Node: Basic Statements, Next: Blocks, Up: Statements - -10.7.1 Basic Statements ------------------------ - -'ASM_EXPR' - - Used to represent an inline assembly statement. For an inline - assembly statement like: - asm ("mov x, y"); - The 'ASM_STRING' macro will return a 'STRING_CST' node for '"mov x, - y"'. If the original statement made use of the extended-assembly - syntax, then 'ASM_OUTPUTS', 'ASM_INPUTS', and 'ASM_CLOBBERS' will - be the outputs, inputs, and clobbers for the statement, represented - as 'STRING_CST' nodes. The extended-assembly syntax looks like: - asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); - The first string is the '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 'NUL'-terminated, - and will contain no embedded 'NUL'-characters. - - If the assembly statement is declared 'volatile', or if the - statement was not an extended assembly statement, and is therefore - implicitly volatile, then the predicate 'ASM_VOLATILE_P' will hold - of the 'ASM_EXPR'. - -'DECL_EXPR' - - Used to represent a local declaration. The 'DECL_EXPR_DECL' macro - can be used to obtain the entity declared. This declaration may be - a '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 'FUNCTION_DECL', - indicating the use of the GCC nested function extension. For more - information, *note Functions::. - -'LABEL_EXPR' - - Used to represent a label. The 'LABEL_DECL' declared by this - statement can be obtained with the 'LABEL_EXPR_LABEL' macro. The - 'IDENTIFIER_NODE' giving the name of the label can be obtained from - the 'LABEL_DECL' with 'DECL_NAME'. - -'GOTO_EXPR' - - Used to represent a 'goto' statement. The 'GOTO_DESTINATION' will - usually be a 'LABEL_DECL'. However, if the "computed goto" - extension has been used, the 'GOTO_DESTINATION' will be an - arbitrary expression indicating the destination. This expression - will always have pointer type. - -'RETURN_EXPR' - - Used to represent a 'return' statement. Operand 0 represents the - value to return. It should either be the 'RESULT_DECL' for the - containing function, or a 'MODIFY_EXPR' or 'INIT_EXPR' setting the - function's 'RESULT_DECL'. It will be 'NULL_TREE' if the statement - was just - return; - -'LOOP_EXPR' - These nodes represent "infinite" loops. The 'LOOP_EXPR_BODY' - represents the body of the loop. It should be executed forever, - unless an 'EXIT_EXPR' is encountered. - -'EXIT_EXPR' - These nodes represent conditional exits from the nearest enclosing - 'LOOP_EXPR'. The single operand is the condition; if it is - nonzero, then the loop should be exited. An 'EXIT_EXPR' will only - appear within a 'LOOP_EXPR'. - -'SWITCH_STMT' - - Used to represent a 'switch' statement. The 'SWITCH_STMT_COND' is - the expression on which the switch is occurring. See the - documentation for an 'IF_STMT' for more information on the - representation used for the condition. The 'SWITCH_STMT_BODY' is - the body of the switch statement. The 'SWITCH_STMT_TYPE' is the - original type of switch expression as given in the source, before - any compiler conversions. - -'CASE_LABEL_EXPR' - - Use to represent a 'case' label, range of 'case' labels, or a - 'default' label. If 'CASE_LOW' is 'NULL_TREE', then this is a - 'default' label. Otherwise, if 'CASE_HIGH' is 'NULL_TREE', then - this is an ordinary 'case' label. In this case, 'CASE_LOW' is an - expression giving the value of the label. Both 'CASE_LOW' and - 'CASE_HIGH' are 'INTEGER_CST' nodes. These values will have the - same type as the condition expression in the switch statement. - - Otherwise, if both 'CASE_LOW' and '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: - case 2 ... 5: - The first value will be 'CASE_LOW', while the second will be - 'CASE_HIGH'. - - -File: gccint.info, Node: Blocks, Next: Statement Sequences, Prev: Basic Statements, Up: Statements - -10.7.2 Blocks -------------- - -Block scopes and the variables they declare in GENERIC are expressed -using the '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 'BIND_EXPR_VARS' in declaration -order through their 'TREE_CHAIN' field. Any runtime initialization is -moved out of 'DECL_INITIAL' and into a statement in the controlled -block. When gimplifying from C or C++, this initialization replaces the -'DECL_STMT'. These variables will never require cleanups. The scope of -these variables is just the body - - 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 'BIND_EXPR'. This strategy may change in the future. - - A C++ program will usually contain more '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 'BIND_EXPR'. - - -File: gccint.info, Node: Statement Sequences, Next: Empty Statements, Prev: Blocks, Up: Statements - -10.7.3 Statement Sequences --------------------------- - -Multiple statements at the same nesting level are collected into a -'STATEMENT_LIST'. Statement lists are modified and traversed using the -interface in 'tree-iterator.h'. - - -File: gccint.info, Node: Empty Statements, Next: Jumps, Prev: Statement Sequences, Up: Statements - -10.7.4 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 -'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 '(void)0'. - - -File: gccint.info, Node: Jumps, Next: Cleanups, Prev: Empty Statements, Up: Statements - -10.7.5 Jumps ------------- - -Other jumps are expressed by either 'GOTO_EXPR' or 'RETURN_EXPR'. - - The operand of a 'GOTO_EXPR' must be either a label or a variable -containing the address to jump to. - - The operand of a 'RETURN_EXPR' is either 'NULL_TREE', 'RESULT_DECL', or -a 'MODIFY_EXPR' which sets the return value. It would be nice to move -the 'MODIFY_EXPR' into a separate statement, but the special return -semantics in 'expand_return' make that difficult. It may still happen -in the future, perhaps by moving most of that logic into -'expand_assignment'. - - -File: gccint.info, Node: Cleanups, Next: OpenMP, Prev: Jumps, Up: Statements - -10.7.6 Cleanups ---------------- - -Destructors for local C++ objects and similar dynamic cleanups are -represented in GIMPLE by a 'TRY_FINALLY_EXPR'. '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: - - 1. Execute the last statement in the sequence and fall off the end. - - 2. Execute a goto statement ('GOTO_EXPR') to an ordinary label outside - the sequence. - - 3. Execute a return statement ('RETURN_EXPR'). - - 4. Throw an exception. This is currently not explicitly represented - in GIMPLE. - - The second sequence is not executed if the first sequence completes by -calling 'setjmp' or '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. - - '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 'RESX_EXPR'. - - -File: gccint.info, Node: OpenMP, Prev: Cleanups, Up: Statements - -10.7.7 OpenMP -------------- - -All the statements starting with 'OMP_' represent directives and clauses -used by the OpenMP API <http://www.openmp.org/>. - -'OMP_PARALLEL' - - Represents '#pragma omp parallel [clause1 ... clauseN]'. It has - four operands: - - Operand '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 'NULL' - and the body is emitted linearly after 'OMP_PARALLEL'. - - Operand 'OMP_PARALLEL_CLAUSES' is the list of clauses associated - with the directive. - - Operand 'OMP_PARALLEL_FN' is created by 'pass_lower_omp', it - contains the 'FUNCTION_DECL' for the function that will contain the - body of the parallel region. - - Operand 'OMP_PARALLEL_DATA_ARG' is also created by - 'pass_lower_omp'. If there are shared variables to be communicated - to the children threads, this operand will contain the 'VAR_DECL' - that contains all the shared values and variables. - -'OMP_FOR' - - Represents '#pragma omp for [clause1 ... clauseN]'. It has 5 - operands: - - Operand 'OMP_FOR_BODY' contains the loop body. - - Operand 'OMP_FOR_CLAUSES' is the list of clauses associated with - the directive. - - Operand 'OMP_FOR_INIT' is the loop initialization code of the form - 'VAR = N1'. - - Operand 'OMP_FOR_COND' is the loop conditional expression of the - form 'VAR {<,>,<=,>=} N2'. - - Operand 'OMP_FOR_INCR' is the loop index increment of the form 'VAR - {+=,-=} INCR'. - - Operand 'OMP_FOR_PRE_BODY' contains side-effect code from operands - 'OMP_FOR_INIT', 'OMP_FOR_COND' and 'OMP_FOR_INC'. These - side-effects are part of the 'OMP_FOR' block but must be evaluated - before the start of loop body. - - The loop index variable 'VAR' must be a signed integer variable, - which is implicitly private to each thread. Bounds 'N1' and 'N2' - and the increment expression '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. - -'OMP_SECTIONS' - - Represents '#pragma omp sections [clause1 ... clauseN]'. - - Operand 'OMP_SECTIONS_BODY' contains the sections body, which in - turn contains a set of 'OMP_SECTION' nodes for each of the - concurrent sections delimited by '#pragma omp section'. - - Operand 'OMP_SECTIONS_CLAUSES' is the list of clauses associated - with the directive. - -'OMP_SECTION' - - Section delimiter for 'OMP_SECTIONS'. - -'OMP_SINGLE' - - Represents '#pragma omp single'. - - Operand 'OMP_SINGLE_BODY' contains the body of code to be executed - by a single thread. - - Operand 'OMP_SINGLE_CLAUSES' is the list of clauses associated with - the directive. - -'OMP_MASTER' - - Represents '#pragma omp master'. - - Operand 'OMP_MASTER_BODY' contains the body of code to be executed - by the master thread. - -'OMP_ORDERED' - - Represents '#pragma omp ordered'. - - Operand 'OMP_ORDERED_BODY' contains the body of code to be executed - in the sequential order dictated by the loop index variable. - -'OMP_CRITICAL' - - Represents '#pragma omp critical [name]'. - - Operand 'OMP_CRITICAL_BODY' is the critical section. - - Operand 'OMP_CRITICAL_NAME' is an optional identifier to label the - critical section. - -'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 ('tree-cfg.c') and OpenMP region building code - ('omp-low.c'). - -'OMP_CONTINUE' - - Similarly, this instruction does not represent an OpenMP directive, - it is used by 'OMP_FOR' and 'OMP_SECTIONS' to mark the place where - the code needs to loop to the next iteration (in the case of - 'OMP_FOR') or the next section (in the case of 'OMP_SECTIONS'). - - In some cases, 'OMP_CONTINUE' is placed right before 'OMP_RETURN'. - But if there are cleanups that need to occur right after the - looping body, it will be emitted between 'OMP_CONTINUE' and - 'OMP_RETURN'. - -'OMP_ATOMIC' - - Represents '#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. - -'OMP_CLAUSE' - - Represents clauses associated with one of the 'OMP_' directives. - Clauses are represented by separate subcodes defined in 'tree.h'. - Clauses codes can be one of: 'OMP_CLAUSE_PRIVATE', - 'OMP_CLAUSE_SHARED', 'OMP_CLAUSE_FIRSTPRIVATE', - 'OMP_CLAUSE_LASTPRIVATE', 'OMP_CLAUSE_COPYIN', - 'OMP_CLAUSE_COPYPRIVATE', 'OMP_CLAUSE_IF', - 'OMP_CLAUSE_NUM_THREADS', 'OMP_CLAUSE_SCHEDULE', - 'OMP_CLAUSE_NOWAIT', 'OMP_CLAUSE_ORDERED', 'OMP_CLAUSE_DEFAULT', - 'OMP_CLAUSE_REDUCTION', 'OMP_CLAUSE_COLLAPSE', 'OMP_CLAUSE_UNTIED', - 'OMP_CLAUSE_FINAL', and 'OMP_CLAUSE_MERGEABLE'. Each code - represents the corresponding OpenMP clause. - - Clauses associated with the same directive are chained together via - 'OMP_CLAUSE_CHAIN'. Those clauses that accept a list of variables - are restricted to exactly one, accessed with 'OMP_CLAUSE_VAR'. - Therefore, multiple variables under the same clause 'C' need to be - represented as multiple 'C' clauses chained together. This - facilitates adding new clauses during compilation. - - -File: gccint.info, Node: Functions, Next: Language-dependent trees, Prev: Statements, Up: GENERIC - -10.8 Functions -============== - -A function is represented by a 'FUNCTION_DECL' node. It stores the -basic pieces of the function such as body, parameters, and return type -as well as information on the surrounding context, visibility, and -linkage. - -* Menu: - -* Function Basics:: Function names, body, and parameters. -* Function Properties:: Context, linkage, etc. - - -File: gccint.info, Node: Function Basics, Next: Function Properties, Up: Functions - -10.8.1 Function Basics ----------------------- - -A function has four core parts: the name, the parameters, the result, -and the body. The following macros and functions access these parts of -a 'FUNCTION_DECL' as well as other basic features: -'DECL_NAME' - This macro returns the unqualified name of the function, as an - 'IDENTIFIER_NODE'. For an instantiation of a function template, - the 'DECL_NAME' is the unqualified name of the template, not - something like 'f<int>'. The value of '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. - -'DECL_ASSEMBLER_NAME' - This macro returns the mangled name of the function, also an - '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 'DECL_ASSEMBLER_NAME' itself.) - - Using '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. - -'DECL_ARGUMENTS' - This macro returns the 'PARM_DECL' for the first argument to the - function. Subsequent 'PARM_DECL' nodes can be obtained by - following the 'TREE_CHAIN' links. - -'DECL_RESULT' - This macro returns the 'RESULT_DECL' for the function. - -'DECL_SAVED_TREE' - This macro returns the complete body of the function. - -'TREE_TYPE' - This macro returns the 'FUNCTION_TYPE' or 'METHOD_TYPE' for the - function. - -'DECL_INITIAL' - A function that has a definition in the current translation unit - will have a non-'NULL' 'DECL_INITIAL'. However, back ends should - not make use of the particular value given by 'DECL_INITIAL'. - - It should contain a tree of 'BLOCK' nodes that mirrors the scopes - that variables are bound in the function. Each block contains a - list of decls declared in a basic block, a pointer to a chain of - blocks at the next lower scope level, then a pointer to the next - block at the same level and a backpointer to the parent 'BLOCK' or - 'FUNCTION_DECL'. So given a function as follows: - - void foo() - { - int a; - { - int b; - } - int c; - } - - you would get the following: - - tree foo = FUNCTION_DECL; - tree decl_a = VAR_DECL; - tree decl_b = VAR_DECL; - tree decl_c = VAR_DECL; - tree block_a = BLOCK; - tree block_b = BLOCK; - tree block_c = BLOCK; - BLOCK_VARS(block_a) = decl_a; - BLOCK_SUBBLOCKS(block_a) = block_b; - BLOCK_CHAIN(block_a) = block_c; - BLOCK_SUPERCONTEXT(block_a) = foo; - BLOCK_VARS(block_b) = decl_b; - BLOCK_SUPERCONTEXT(block_b) = block_a; - BLOCK_VARS(block_c) = decl_c; - BLOCK_SUPERCONTEXT(block_c) = foo; - DECL_INITIAL(foo) = block_a; - - -File: gccint.info, Node: Function Properties, Prev: Function Basics, Up: Functions - -10.8.2 Function Properties --------------------------- - -To determine the scope of a function, you can use the 'DECL_CONTEXT' -macro. This macro will return the class (either a 'RECORD_TYPE' or a -'UNION_TYPE') or namespace (a '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. - - In C, the '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 'DECL_CONTEXT' for the -referenced 'VAR_DECL'. If the 'DECL_CONTEXT' for the referenced -'VAR_DECL' is not the same as the function currently being processed, -and neither 'DECL_EXTERNAL' nor 'TREE_STATIC' hold, then the reference -is to a local variable in a containing function, and the back end must -take appropriate action. - -'DECL_EXTERNAL' - This predicate holds if the function is undefined. - -'TREE_PUBLIC' - This predicate holds if the function has external linkage. - -'TREE_STATIC' - This predicate holds if the function has been defined. - -'TREE_THIS_VOLATILE' - This predicate holds if the function does not return normally. - -'TREE_READONLY' - This predicate holds if the function can only read its arguments. - -'DECL_PURE_P' - This predicate holds if the function can only read its arguments, - but may also read global memory. - -'DECL_VIRTUAL_P' - This predicate holds if the function is virtual. - -'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. - -'DECL_FUNCTION_SPECIFIC_TARGET' - This macro returns a tree node that holds the target options that - are to be used to compile this particular function or 'NULL_TREE' - if the function is to be compiled with the target options specified - on the command line. - -'DECL_FUNCTION_SPECIFIC_OPTIMIZATION' - This macro returns a tree node that holds the optimization options - that are to be used to compile this particular function or - 'NULL_TREE' if the function is to be compiled with the optimization - options specified on the command line. - - -File: gccint.info, Node: Language-dependent trees, Next: C and C++ Trees, Prev: Functions, Up: GENERIC - -10.9 Language-dependent trees -============================= - -Front ends may wish to keep some state associated with various GENERIC -trees while parsing. To support this, trees provide a set of flags that -may be used by the front end. They are accessed using -'TREE_LANG_FLAG_n' where 'n' is currently 0 through 6. - - 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. - - -File: gccint.info, Node: C and C++ Trees, Next: Java Trees, Prev: Language-dependent trees, Up: GENERIC - -10.10 C and C++ Trees -===================== - -This section 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 section 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. - - The C and C++ front ends generate a mix of GENERIC trees and ones -specific to C and C++. These language-specific trees are higher-level -constructs than the ones in GENERIC to make the parser's job easier. -This section describes those trees that aren't part of GENERIC as well -as aspects of GENERIC trees that are treated in a language-specific -manner. - - 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 <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: - -* Types for C++:: Fundamental and aggregate types. -* Namespaces:: Namespaces. -* Classes:: Classes. -* Functions for C++:: Overloading and accessors for C++. -* Statements for C++:: Statements specific to C and C++. -* C++ Expressions:: From 'typeid' to 'throw'. - - -File: gccint.info, Node: Types for C++, Next: Namespaces, Up: C and C++ Trees - -10.10.1 Types for C++ ---------------------- - -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, 'CP_TYPE_CONST_P' will hold of the -type 'const int ()[7]', denoting an array of seven 'int's. - - The following functions and macros deal with cv-qualification of types: -'cp_type_quals' - This function returns the set of type qualifiers applied to this - type. This value is 'TYPE_UNQUALIFIED' if no qualifiers have been - applied. The 'TYPE_QUAL_CONST' bit is set if the type is - 'const'-qualified. The 'TYPE_QUAL_VOLATILE' bit is set if the type - is 'volatile'-qualified. The 'TYPE_QUAL_RESTRICT' bit is set if - the type is 'restrict'-qualified. - -'CP_TYPE_CONST_P' - This macro holds if the type is 'const'-qualified. - -'CP_TYPE_VOLATILE_P' - This macro holds if the type is 'volatile'-qualified. - -'CP_TYPE_RESTRICT_P' - This macro holds if the type is 'restrict'-qualified. - -'CP_TYPE_CONST_NON_VOLATILE_P' - This predicate holds for a type that is 'const'-qualified, but - _not_ 'volatile'-qualified; other cv-qualifiers are ignored as - well: only the 'const'-ness is tested. - - A few other macros and functions are usable with all types: -'TYPE_SIZE' - The number of bits required to represent the type, represented as - an 'INTEGER_CST'. For an incomplete type, 'TYPE_SIZE' will be - 'NULL_TREE'. - -'TYPE_ALIGN' - The alignment of the type, in bits, represented as an 'int'. - -'TYPE_NAME' - This macro returns a declaration (in the form of a 'TYPE_DECL') for - the type. (Note this macro does _not_ return an 'IDENTIFIER_NODE', - as you might expect, given its name!) You can look at the - 'DECL_NAME' of the 'TYPE_DECL' to obtain the actual name of the - type. The 'TYPE_NAME' will be 'NULL_TREE' for a type that is not a - built-in type, the result of a typedef, or a named class type. - -'CP_INTEGRAL_TYPE' - This predicate holds if the type is an integral type. Notice that - in C++, enumerations are _not_ integral types. - -'ARITHMETIC_TYPE_P' - This predicate holds if the type is an integral type (in the C++ - sense) or a floating point type. - -'CLASS_TYPE_P' - This predicate holds for a class-type. - -'TYPE_BUILT_IN' - This predicate holds for a built-in type. - -'TYPE_PTRDATAMEM_P' - This predicate holds if the type is a pointer to data member. - -'TYPE_PTR_P' - This predicate holds if the type is a pointer type, and the pointee - is not a data member. - -'TYPE_PTRFN_P' - This predicate holds for a pointer to function type. - -'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 'void - *'. You may use 'TYPE_PTROBV_P' to test for a pointer to object - type as well as 'void *'. - - The table below describes types specific to C and C++ as well as -language-dependent info about GENERIC types. - -'POINTER_TYPE' - Used to represent pointer types, and pointer to data member types. - If 'TREE_TYPE' is a pointer to data member type, then - 'TYPE_PTRDATAMEM_P' will hold. For a pointer to data member type - of the form 'T X::*', 'TYPE_PTRMEM_CLASS_TYPE' will be the type - 'X', while 'TYPE_PTRMEM_POINTED_TO_TYPE' will be the type 'T'. - -'RECORD_TYPE' - Used to represent 'struct' and 'class' types in C and C++. If - 'TYPE_PTRMEMFUNC_P' holds, then this type is a pointer-to-member - type. In that case, the 'TYPE_PTRMEMFUNC_FN_TYPE' is a - 'POINTER_TYPE' pointing to a 'METHOD_TYPE'. The 'METHOD_TYPE' is - the type of a function pointed to by the pointer-to-member - function. If 'TYPE_PTRMEMFUNC_P' does not hold, this type is a - class type. For more information, *note Classes::. - -'UNKNOWN_TYPE' - This node is used to represent a type the knowledge of which is - insufficient for a sound processing. - -'TYPENAME_TYPE' - Used to represent a construct of the form 'typename T::A'. The - 'TYPE_CONTEXT' is 'T'; the 'TYPE_NAME' is an 'IDENTIFIER_NODE' for - 'A'. If the type is specified via a template-id, then - 'TYPENAME_TYPE_FULLNAME' yields a 'TEMPLATE_ID_EXPR'. The - 'TREE_TYPE' is non-'NULL' if the node is implicitly generated in - support for the implicit typename extension; in which case the - 'TREE_TYPE' is a type node for the base-class. - -'TYPEOF_TYPE' - Used to represent the '__typeof__' extension. The 'TYPE_FIELDS' is - the expression the type of which is being represented. - - -File: gccint.info, Node: Namespaces, Next: Classes, Prev: Types for C++, Up: C and C++ Trees - -10.10.2 Namespaces ------------------- - -The root of the entire intermediate representation is the variable -'global_namespace'. This is the namespace specified with '::' in C++ -source code. All other namespaces, types, variables, functions, and so -forth can be found starting with this namespace. - - 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. - - A namespace is represented by a 'NAMESPACE_DECL' node. - - The following macros and functions can be used on a 'NAMESPACE_DECL': - -'DECL_NAME' - This macro is used to obtain the 'IDENTIFIER_NODE' corresponding to - the unqualified name of the name of the namespace (*note - Identifiers::). The name of the global namespace is '::', even - though in C++ the global namespace is unnamed. However, you should - use comparison with 'global_namespace', rather than 'DECL_NAME' to - determine whether or not a namespace is the global one. An unnamed - namespace will have a 'DECL_NAME' equal to - 'anonymous_namespace_name'. Within a single translation unit, all - unnamed namespaces will have the same name. - -'DECL_CONTEXT' - This macro returns the enclosing namespace. The 'DECL_CONTEXT' for - the 'global_namespace' is 'NULL_TREE'. - -'DECL_NAMESPACE_ALIAS' - If this declaration is for a namespace alias, then - 'DECL_NAMESPACE_ALIAS' is the namespace for which this one is an - alias. - - Do not attempt to use 'cp_namespace_decls' for a namespace which is - an alias. Instead, follow 'DECL_NAMESPACE_ALIAS' links until you - reach an ordinary, non-alias, namespace, and call - 'cp_namespace_decls' there. - -'DECL_NAMESPACE_STD_P' - This predicate holds if the namespace is the special '::std' - namespace. - -'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 'NULL_TREE'. The declarations are connected through their - 'TREE_CHAIN' fields. - - Although most entries on this list will be declarations, - 'TREE_LIST' nodes may also appear. In this case, the 'TREE_VALUE' - will be an 'OVERLOAD'. The value of the 'TREE_PURPOSE' is - unspecified; back ends should ignore this value. As with the other - kinds of declarations returned by 'cp_namespace_decls', the - '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, *Note Declarations::. Some declarations will not appear - on this list. In particular, no 'FIELD_DECL', 'LABEL_DECL', or - 'PARM_DECL' nodes will appear here. - - This function cannot be used with namespaces that have - 'DECL_NAMESPACE_ALIAS' set. - - -File: gccint.info, Node: Classes, Next: Functions for C++, Prev: Namespaces, Up: C and C++ Trees - -10.10.3 Classes ---------------- - -Besides namespaces, the other high-level scoping construct in C++ is the -class. (Throughout this manual the term "class" is used to mean the -types referred to in the ANSI/ISO C++ Standard as classes; these include -types defined with the 'class', 'struct', and 'union' keywords.) - - A class type is represented by either a 'RECORD_TYPE' or a -'UNION_TYPE'. A class declared with the 'union' tag is represented by a -'UNION_TYPE', while classes declared with either the 'struct' or the -'class' tag are represented by 'RECORD_TYPE's. You can use the -'CLASSTYPE_DECLARED_CLASS' macro to discern whether or not a particular -type is a 'class' as opposed to a 'struct'. This macro will be true -only for classes declared with the 'class' tag. - - Almost all non-function members are available on the 'TYPE_FIELDS' -list. Given one member, the next can be found by following the -'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 'DECL' -nodes. A 'FIELD_DECL' is used to represent a non-static data member, a -'VAR_DECL' is used to represent a static data member, and a 'TYPE_DECL' -is used to represent a type. Note that the 'CONST_DECL' for an -enumeration constant will appear on this list, if the enumeration type -was declared in the class. (Of course, the '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 'FIELD_DECL' for -the "base-class portion" of an object. - - The 'TYPE_VFIELD' is a compiler-generated field used to point to -virtual function tables. It may or may not appear on the 'TYPE_FIELDS' -list. However, back ends should handle the 'TYPE_VFIELD' just like all -the entries on the 'TYPE_FIELDS' list. - - The function members are available on the 'TYPE_METHODS' list. Again, -subsequent members are found by following the 'TREE_CHAIN' field. If a -function is overloaded, each of the overloaded functions appears; no -'OVERLOAD' nodes appear on the '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 "binfo", which can be obtained with -'TYPE_BINFO'. Binfos are used to represent base-classes. The binfo -given by '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 -'BINFO_N_BASE_BINFOS'. The base binfos themselves are obtained with -'BINFO_BASE_BINFO' and 'BINFO_BASE_ITERATE'. To add a new binfo, use -'BINFO_BASE_APPEND'. The vector of base binfos can be obtained with -'BINFO_BASE_BINFOS', but normally you do not need to use that. The -class type associated with a binfo is given by 'BINFO_TYPE'. It is not -always the case that 'BINFO_TYPE (TYPE_BINFO (x))', because of typedefs -and qualified types. Neither is it the case that 'TYPE_BINFO -(BINFO_TYPE (y))' is the same binfo as 'y'. The reason is that if 'y' -is a binfo representing a base-class 'B' of a derived class 'D', then -'BINFO_TYPE (y)' will be 'B', and 'TYPE_BINFO (BINFO_TYPE (y))' will be -'B' as its own base-class, rather than as a base-class of 'D'. - - The access to a base type can be found with 'BINFO_BASE_ACCESS'. This -will produce 'access_public_node', 'access_private_node' or -'access_protected_node'. If bases are always public, -'BINFO_BASE_ACCESSES' may be 'NULL'. - - 'BINFO_VIRTUAL_P' is used to specify whether the binfo is inherited -virtually or not. The other flags, 'BINFO_MARKED_P' and 'BINFO_FLAG_1' -to 'BINFO_FLAG_6' can be used for language specific use. - - The following macros can be used on a tree node representing a -class-type. - -'LOCAL_CLASS_P' - This predicate holds if the class is local class _i.e._ declared - inside a function body. - -'TYPE_POLYMORPHIC_P' - This predicate holds if the class has at least one virtual function - (declared or inherited). - -'TYPE_HAS_DEFAULT_CONSTRUCTOR' - This predicate holds whenever its argument represents a class-type - with default constructor. - -'CLASSTYPE_HAS_MUTABLE' -'TYPE_HAS_MUTABLE_P' - These predicates hold for a class-type having a mutable data - member. - -'CLASSTYPE_NON_POD_P' - This predicate holds only for class-types that are not PODs. - -'TYPE_HAS_NEW_OPERATOR' - This predicate holds for a class-type that defines 'operator new'. - -'TYPE_HAS_ARRAY_NEW_OPERATOR' - This predicate holds for a class-type for which 'operator new[]' is - defined. - -'TYPE_OVERLOADS_CALL_EXPR' - This predicate holds for class-type for which the function call - 'operator()' is overloaded. - -'TYPE_OVERLOADS_ARRAY_REF' - This predicate holds for a class-type that overloads 'operator[]' - -'TYPE_OVERLOADS_ARROW' - This predicate holds for a class-type for which 'operator->' is - overloaded. - - -File: gccint.info, Node: Functions for C++, Next: Statements for C++, Prev: Classes, Up: C and C++ Trees - -10.10.4 Functions for C++ -------------------------- - -A function is represented by a 'FUNCTION_DECL' node. A set of -overloaded functions is sometimes represented by an 'OVERLOAD' node. - - An 'OVERLOAD' node is not a declaration, so none of the 'DECL_' macros -should be used on an 'OVERLOAD'. An 'OVERLOAD' node is similar to a -'TREE_LIST'. Use 'OVL_CURRENT' to get the function associated with an -'OVERLOAD' node; use 'OVL_NEXT' to get the next 'OVERLOAD' node in the -list of overloaded functions. The macros 'OVL_CURRENT' and 'OVL_NEXT' -are actually polymorphic; you can use them to work with 'FUNCTION_DECL' -nodes as well as with overloads. In the case of a 'FUNCTION_DECL', -'OVL_CURRENT' will always return the function itself, and 'OVL_NEXT' -will always be 'NULL_TREE'. - - To determine the scope of a function, you can use the 'DECL_CONTEXT' -macro. This macro will return the class (either a 'RECORD_TYPE' or a -'UNION_TYPE') or namespace (a '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 -'DECL_FRIEND_CONTEXT' macro can be used to determine the class in which -it was defined. For example, in - class C { friend void f() {} }; -the 'DECL_CONTEXT' for 'f' will be the 'global_namespace', but the -'DECL_FRIEND_CONTEXT' will be the 'RECORD_TYPE' for 'C'. - - The following macros and functions can be used on a 'FUNCTION_DECL': -'DECL_MAIN_P' - This predicate holds for a function that is the program entry point - '::code'. - -'DECL_LOCAL_FUNCTION_P' - This predicate holds if the function was declared at block scope, - even though it has a global scope. - -'DECL_ANTICIPATED' - This predicate holds if the function is a built-in function but its - prototype is not yet explicitly declared. - -'DECL_EXTERN_C_FUNCTION_P' - This predicate holds if the function is declared as an ''extern - "C"'' function. - -'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 '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. - -'DECL_FUNCTION_MEMBER_P' - This macro holds if the function is a member of a class, rather - than a member of a namespace. - -'DECL_STATIC_FUNCTION_P' - This predicate holds if the function a static member function. - -'DECL_NONSTATIC_MEMBER_FUNCTION_P' - This macro holds for a non-static member function. - -'DECL_CONST_MEMFUNC_P' - This predicate holds for a 'const'-member function. - -'DECL_VOLATILE_MEMFUNC_P' - This predicate holds for a 'volatile'-member function. - -'DECL_CONSTRUCTOR_P' - This macro holds if the function is a constructor. - -'DECL_NONCONVERTING_P' - This predicate holds if the constructor is a non-converting - constructor. - -'DECL_COMPLETE_CONSTRUCTOR_P' - This predicate holds for a function which is a constructor for an - object of a complete type. - -'DECL_BASE_CONSTRUCTOR_P' - This predicate holds for a function which is a constructor for a - base class sub-object. - -'DECL_COPY_CONSTRUCTOR_P' - This predicate holds for a function which is a copy-constructor. - -'DECL_DESTRUCTOR_P' - This macro holds if the function is a destructor. - -'DECL_COMPLETE_DESTRUCTOR_P' - This predicate holds if the function is the destructor for an - object a complete type. - -'DECL_OVERLOADED_OPERATOR_P' - This macro holds if the function is an overloaded operator. - -'DECL_CONV_FN_P' - This macro holds if the function is a type-conversion operator. - -'DECL_GLOBAL_CTOR_P' - This predicate holds if the function is a file-scope initialization - function. - -'DECL_GLOBAL_DTOR_P' - This predicate holds if the function is a file-scope finalization - function. - -'DECL_THUNK_P' - This predicate holds if the function is a thunk. - - These functions represent stub code that adjusts the '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 'this' pointer; the thunk should add 'THUNK_DELTA' to this - value. (The 'THUNK_DELTA' is an 'int', not an 'INTEGER_CST'.) - - Then, if 'THUNK_VCALL_OFFSET' (an 'INTEGER_CST') is nonzero the - adjusted 'this' pointer must be adjusted again. The complete - calculation is given by the following pseudo-code: - - this += THUNK_DELTA - if (THUNK_VCALL_OFFSET) - this += (*((ptrdiff_t **) this))[THUNK_VCALL_OFFSET] - - Finally, the thunk should jump to the location given by - 'DECL_INITIAL'; this will always be an expression for the address - of a function. - -'DECL_NON_THUNK_FUNCTION_P' - This predicate holds if the function is _not_ a thunk function. - -'GLOBAL_INIT_PRIORITY' - If either 'DECL_GLOBAL_CTOR_P' or 'DECL_GLOBAL_DTOR_P' holds, then - this gives the initialization priority for the function. The - linker will arrange that all functions for which - 'DECL_GLOBAL_CTOR_P' holds are run in increasing order of priority - before 'main' is called. When the program exits, all functions for - which 'DECL_GLOBAL_DTOR_P' holds are run in the reverse order. - -'TYPE_RAISES_EXCEPTIONS' - This macro returns the list of exceptions that a (member-)function - can raise. The returned list, if non 'NULL', is comprised of nodes - whose 'TREE_VALUE' represents a type. - -'TYPE_NOTHROW_P' - This predicate holds when the exception-specification of its - arguments is of the form ''()''. - -'DECL_ARRAY_DELETE_OPERATOR_P' - This predicate holds if the function an overloaded 'operator - delete[]'. - - -File: gccint.info, Node: Statements for C++, Next: C++ Expressions, Prev: Functions for C++, Up: C and C++ Trees - -10.10.5 Statements for C++ --------------------------- - -A function that has a definition in the current translation unit will -have a non-'NULL' 'DECL_INITIAL'. However, back ends should not make -use of the particular value given by 'DECL_INITIAL'. - - The 'DECL_SAVED_TREE' macro will give the complete body of the -function. - -10.10.5.1 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: - -'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 - 'STMT_IS_FULL_EXPR_P' set. Temporaries created during such - statements should be destroyed when the innermost enclosing - statement with 'STMT_IS_FULL_EXPR_P' set is exited. - - 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 'while' loop -will have a body, which is itself a statement. If the substatement is -'NULL_TREE', it is considered equivalent to a statement consisting of a -single ';', 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 'TREE_CHAIN's. So, you should always process the -statement tree by looping over substatements, like this: - void process_stmt (stmt) - tree stmt; - { - while (stmt) - { - switch (TREE_CODE (stmt)) - { - case IF_STMT: - process_stmt (THEN_CLAUSE (stmt)); - /* More processing here. */ - break; - - ... - } - - stmt = TREE_CHAIN (stmt); - } - } - In other words, while the 'then' clause of an '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. - -'BREAK_STMT' - - Used to represent a 'break' statement. There are no additional - fields. - -'CILK_SPAWN_STMT' - - Used to represent a spawning function in the Cilk Plus language - extension. This tree has one field that holds the name of the - spawning function. '_Cilk_spawn' can be written in C in the - following way: - - _Cilk_spawn <function_name> (<parameters>); - - Detailed description for usage and functionality of '_Cilk_spawn' - can be found at http://www.cilkplus.org - -'CILK_SYNC_STMT' - - This statement is part of the Cilk Plus language extension. It - indicates that the current function cannot continue in parallel - with its spawned children. There are no additional fields. - '_Cilk_sync' can be written in C in the following way: - - _Cilk_sync; - -'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, - 'CLEANUP_DECL' will be the 'VAR_DECL' destroyed. Otherwise, - 'CLEANUP_DECL' will be 'NULL_TREE'. In any case, the - '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 'CLEANUP_STMT's were encountered. - -'CONTINUE_STMT' - - Used to represent a 'continue' statement. There are no additional - fields. - -'CTOR_STMT' - - Used to mark the beginning (if 'CTOR_BEGIN_P' holds) or end (if - 'CTOR_END_P' holds of the main body of a constructor. See also - 'SUBOBJECT' for more information on how to use these nodes. - -'DO_STMT' - - Used to represent a 'do' loop. The body of the loop is given by - 'DO_BODY' while the termination condition for the loop is given by - 'DO_COND'. The condition for a 'do'-statement is always an - expression. - -'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 'TREE_TYPE' represents the type of the object. - -'EXPR_STMT' - - Used to represent an expression statement. Use 'EXPR_STMT_EXPR' to - obtain the expression. - -'FOR_STMT' - - Used to represent a 'for' statement. The 'FOR_INIT_STMT' is the - initialization statement for the loop. The 'FOR_COND' is the - termination condition. The 'FOR_EXPR' is the expression executed - right before the 'FOR_COND' on each loop iteration; often, this - expression increments a counter. The body of the loop is given by - 'FOR_BODY'. Note that 'FOR_INIT_STMT' and 'FOR_BODY' return - statements, while 'FOR_COND' and 'FOR_EXPR' return expressions. - -'HANDLER' - - Used to represent a C++ 'catch' block. The 'HANDLER_TYPE' is the - type of exception that will be caught by this handler; it is equal - (by pointer equality) to 'NULL' if this handler is for all types. - 'HANDLER_PARMS' is the 'DECL_STMT' for the catch parameter, and - 'HANDLER_BODY' is the code for the block itself. - -'IF_STMT' - - Used to represent an 'if' statement. The 'IF_COND' is the - expression. - - If the condition is a 'TREE_LIST', then the 'TREE_PURPOSE' is a - statement (usually a 'DECL_STMT'). Each time the condition is - evaluated, the statement should be executed. Then, the - 'TREE_VALUE' should be used as the conditional expression itself. - This representation is used to handle C++ code like this: - - C++ distinguishes between this and 'COND_EXPR' for handling - templates. - - if (int i = 7) ... - - where there is a new local variable (or variables) declared within - the condition. - - The 'THEN_CLAUSE' represents the statement given by the 'then' - condition, while the 'ELSE_CLAUSE' represents the statement given - by the 'else' condition. - -'SUBOBJECT' - - In a constructor, these nodes are used to mark the point at which a - subobject of 'this' is fully constructed. If, after this point, an - exception is thrown before a 'CTOR_STMT' with 'CTOR_END_P' set is - encountered, the 'SUBOBJECT_CLEANUP' must be executed. The - cleanups must be executed in the reverse order in which they - appear. - -'SWITCH_STMT' - - Used to represent a 'switch' statement. The 'SWITCH_STMT_COND' is - the expression on which the switch is occurring. See the - documentation for an 'IF_STMT' for more information on the - representation used for the condition. The 'SWITCH_STMT_BODY' is - the body of the switch statement. The 'SWITCH_STMT_TYPE' is the - original type of switch expression as given in the source, before - any compiler conversions. - -'TRY_BLOCK' - Used to represent a 'try' block. The body of the try block is - given by 'TRY_STMTS'. Each of the catch blocks is a 'HANDLER' - node. The first handler is given by 'TRY_HANDLERS'. Subsequent - handlers are obtained by following the 'TREE_CHAIN' link from one - handler to the next. The body of the handler is given by - 'HANDLER_BODY'. - - If 'CLEANUP_P' holds of the 'TRY_BLOCK', then the 'TRY_HANDLERS' - will not be a '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, - 'terminate' must be called. - -'USING_STMT' - Used to represent a 'using' directive. The namespace is given by - 'USING_STMT_NAMESPACE', which will be a NAMESPACE_DECL. This node - is needed inside template functions, to implement using directives - during instantiation. - -'WHILE_STMT' - - Used to represent a 'while' loop. The 'WHILE_COND' is the - termination condition for the loop. See the documentation for an - 'IF_STMT' for more information on the representation used for the - condition. - - The 'WHILE_BODY' is the body of the loop. - - -File: gccint.info, Node: C++ Expressions, Prev: Statements for C++, Up: C and C++ Trees - -10.10.6 C++ Expressions ------------------------ - -This section describes expressions specific to the C and C++ front ends. - -'TYPEID_EXPR' - - Used to represent a 'typeid' expression. - -'NEW_EXPR' -'VEC_NEW_EXPR' - - Used to represent a call to 'new' and 'new[]' respectively. - -'DELETE_EXPR' -'VEC_DELETE_EXPR' - - Used to represent a call to 'delete' and 'delete[]' respectively. - -'MEMBER_REF' - - Represents a reference to a member of a class. - -'THROW_EXPR' - - Represents an instance of 'throw' in the program. Operand 0, which - is the expression to throw, may be 'NULL_TREE'. - -'AGGR_INIT_EXPR' - An 'AGGR_INIT_EXPR' represents the initialization as the return - value of a function call, or as the result of a constructor. An - 'AGGR_INIT_EXPR' will only appear as a full-expression, or as the - second operand of a 'TARGET_EXPR'. 'AGGR_INIT_EXPR's have a - representation similar to that of 'CALL_EXPR's. You can use the - 'AGGR_INIT_EXPR_FN' and 'AGGR_INIT_EXPR_ARG' macros to access the - function to call and the arguments to pass. - - If 'AGGR_INIT_VIA_CTOR_P' holds of the 'AGGR_INIT_EXPR', then the - initialization is via a constructor call. The address of the - 'AGGR_INIT_EXPR_SLOT' operand, which is always a 'VAR_DECL', is - taken, and this value replaces the first argument in the argument - list. - - In either case, the expression is void. - - -File: gccint.info, Node: Java Trees, Prev: C and C++ Trees, Up: GENERIC - -10.11 Java Trees -================ - - -File: gccint.info, Node: GIMPLE, Next: Tree SSA, Prev: GENERIC, Up: Top - -11 GIMPLE -********* - -GIMPLE is a three-address representation derived from GENERIC by -breaking down GENERIC expressions into tuples of no more than 3 operands -(with some exceptions like function calls). GIMPLE 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 'goto'. - - Temporaries are introduced to hold intermediate values needed to -compute complex expressions. Additionally, all the control structures -used in GENERIC are lowered into conditional jumps, lexical scopes are -removed and exception regions are converted into an on the side -exception region tree. - - The compiler pass which converts GENERIC into GIMPLE is referred to as -the 'gimplifier'. The gimplifier works recursively, generating GIMPLE -tuples out of the original GENERIC expressions. - - One of the early implementation strategies used for the GIMPLE -representation was to use the same internal data structures used by -front ends to represent parse trees. This simplified implementation -because we could leverage existing functionality and interfaces. -However, GIMPLE is a much more restrictive representation than abstract -syntax trees (AST), therefore it does not require the full structural -complexity provided by the main tree data structure. - - The GENERIC representation of a function is stored in the -'DECL_SAVED_TREE' field of the associated 'FUNCTION_DECL' tree node. It -is converted to GIMPLE by a call to '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 '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 'pass_lower_cf'. High GIMPLE contains some -container statements like lexical scopes (represented by 'GIMPLE_BIND') -and nested expressions (e.g., 'GIMPLE_TRY'), while "Low GIMPLE" exposes -all of the implicit jumps for control and exception expressions directly -in the IL and EH region trees. - - 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 -'_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 '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. - - You can request to dump a C-like representation of the GIMPLE form with -the flag '-fdump-tree-gimple'. - -* Menu: - -* Tuple representation:: -* GIMPLE instruction set:: -* GIMPLE Exception Handling:: -* Temporaries:: -* Operands:: -* Manipulating GIMPLE statements:: -* Tuple specific accessors:: -* GIMPLE sequences:: -* Sequence iterators:: -* Adding a new GIMPLE statement code:: -* Statement and operand traversals:: - - -File: gccint.info, Node: Tuple representation, Next: GIMPLE instruction set, Up: GIMPLE - -11.1 Tuple representation -========================= - -GIMPLE instructions are tuples of variable size divided in two groups: a -header describing the instruction and its locations, and a variable -length body with all the operands. Tuples are organized into a -hierarchy with 3 main classes of tuples. - -11.1.1 'gimple_statement_base' (gsbase) ---------------------------------------- - -This is the root of the hierarchy, it holds basic information needed by -most GIMPLE statements. There are some fields that may not be relevant -to every GIMPLE statement, but those were moved into the base structure -to take advantage of holes left by other fields (thus making the -structure more compact). The structure takes 4 words (32 bytes) on 64 -bit hosts: - -Field Size (bits) -'code' 8 -'subcode' 16 -'no_warning' 1 -'visited' 1 -'nontemporal_move' 1 -'plf' 2 -'modified' 1 -'has_volatile_ops' 1 -'references_memory_p' 1 -'uid' 32 -'location' 32 -'num_ops' 32 -'bb' 64 -'block' 63 -Total size 32 bytes - - * 'code' Main identifier for a GIMPLE instruction. - - * 'subcode' Used to distinguish different variants of the same basic - instruction or provide flags applicable to a given code. The - 'subcode' flags field has different uses depending on the code of - the instruction, but mostly it distinguishes instructions of the - same family. The most prominent use of this field is in - assignments, where subcode indicates the operation done on the RHS - of the assignment. For example, a = b + c is encoded as - 'GIMPLE_ASSIGN <PLUS_EXPR, a, b, c>'. - - * 'no_warning' Bitflag to indicate whether a warning has already been - issued on this statement. - - * 'visited' General purpose "visited" marker. Set and cleared by - each pass when needed. - - * 'nontemporal_move' Bitflag used in assignments that represent - non-temporal moves. Although this bitflag is only used in - assignments, it was moved into the base to take advantage of the - bit holes left by the previous fields. - - * 'plf' Pass Local Flags. This 2-bit mask can be used as general - purpose markers by any pass. Passes are responsible for clearing - and setting these two flags accordingly. - - * 'modified' Bitflag to indicate whether the statement has been - modified. Used mainly by the operand scanner to determine when to - re-scan a statement for operands. - - * 'has_volatile_ops' Bitflag to indicate whether this statement - contains operands that have been marked volatile. - - * 'references_memory_p' Bitflag to indicate whether this statement - contains memory references (i.e., its operands are either global - variables, or pointer dereferences or anything that must reside in - memory). - - * 'uid' This is an unsigned integer used by passes that want to - assign IDs to every statement. These IDs must be assigned and used - by each pass. - - * 'location' This is a 'location_t' identifier to specify source code - location for this statement. It is inherited from the front end. - - * 'num_ops' Number of operands that this statement has. This - specifies the size of the operand vector embedded in the tuple. - Only used in some tuples, but it is declared in the base tuple to - take advantage of the 32-bit hole left by the previous fields. - - * 'bb' Basic block holding the instruction. - - * 'block' Lexical block holding this statement. Also used for debug - information generation. - -11.1.2 'gimple_statement_with_ops' ----------------------------------- - -This tuple is actually split in two: 'gimple_statement_with_ops_base' -and 'gimple_statement_with_ops'. This is needed to accommodate the way -the operand vector is allocated. The operand vector is defined to be an -array of 1 element. So, to allocate a dynamic number of operands, the -memory allocator ('gimple_alloc') simply allocates enough memory to hold -the structure itself plus 'N - 1' operands which run "off the end" of -the structure. For example, to allocate space for a tuple with 3 -operands, 'gimple_alloc' reserves 'sizeof (struct -gimple_statement_with_ops) + 2 * sizeof (tree)' bytes. - - On the other hand, several fields in this tuple need to be shared with -the 'gimple_statement_with_memory_ops' tuple. So, these common fields -are placed in 'gimple_statement_with_ops_base' which is then inherited -from the other two tuples. - -'gsbase' 256 -'def_ops' 64 -'use_ops' 64 -'op' 'num_ops' * 64 -Total 48 + 8 * 'num_ops' bytes -size - - * 'gsbase' Inherited from 'struct gimple_statement_base'. - - * 'def_ops' Array of pointers into the operand array indicating all - the slots that contain a variable written-to by the statement. - This array is also used for immediate use chaining. Note that it - would be possible to not rely on this array, but the changes - required to implement this are pretty invasive. - - * 'use_ops' Similar to 'def_ops' but for variables read by the - statement. - - * 'op' Array of trees with 'num_ops' slots. - -11.1.3 'gimple_statement_with_memory_ops' ------------------------------------------ - -This tuple is essentially identical to 'gimple_statement_with_ops', -except that it contains 4 additional fields to hold vectors related -memory stores and loads. Similar to the previous case, the structure is -split in two to accommodate for the operand vector -('gimple_statement_with_memory_ops_base' and -'gimple_statement_with_memory_ops'). - -Field Size (bits) -'gsbase' 256 -'def_ops' 64 -'use_ops' 64 -'vdef_ops' 64 -'vuse_ops' 64 -'stores' 64 -'loads' 64 -'op' 'num_ops' * 64 -Total size 80 + 8 * 'num_ops' bytes - - * 'vdef_ops' Similar to 'def_ops' but for 'VDEF' operators. There is - one entry per memory symbol written by this statement. This is - used to maintain the memory SSA use-def and def-def chains. - - * 'vuse_ops' Similar to 'use_ops' but for 'VUSE' operators. There is - one entry per memory symbol loaded by this statement. This is used - to maintain the memory SSA use-def chains. - - * 'stores' Bitset with all the UIDs for the symbols written-to by the - statement. This is different than 'vdef_ops' in that all the - affected symbols are mentioned in this set. If memory partitioning - is enabled, the 'vdef_ops' vector will refer to memory partitions. - Furthermore, no SSA information is stored in this set. - - * 'loads' Similar to 'stores', but for memory loads. (Note that - there is some amount of redundancy here, it should be possible to - reduce memory utilization further by removing these sets). - - All the other tuples are defined in terms of these three basic ones. -Each tuple will add some fields. The main gimple type is defined to be -the union of all these structures ('GTY' markers elided for clarity): - - union gimple_statement_d - { - struct gimple_statement_base gsbase; - struct gimple_statement_with_ops gsops; - struct gimple_statement_with_memory_ops gsmem; - struct gimple_statement_omp omp; - struct gimple_statement_bind gimple_bind; - struct gimple_statement_catch gimple_catch; - struct gimple_statement_eh_filter gimple_eh_filter; - struct gimple_statement_phi gimple_phi; - struct gimple_statement_resx gimple_resx; - struct gimple_statement_try gimple_try; - struct gimple_statement_wce gimple_wce; - struct gimple_statement_asm gimple_asm; - struct gimple_statement_omp_critical gimple_omp_critical; - struct gimple_statement_omp_for gimple_omp_for; - struct gimple_statement_omp_parallel gimple_omp_parallel; - struct gimple_statement_omp_task gimple_omp_task; - struct gimple_statement_omp_sections gimple_omp_sections; - struct gimple_statement_omp_single gimple_omp_single; - struct gimple_statement_omp_continue gimple_omp_continue; - struct gimple_statement_omp_atomic_load gimple_omp_atomic_load; - struct gimple_statement_omp_atomic_store gimple_omp_atomic_store; - }; - - -File: gccint.info, Node: GIMPLE instruction set, Next: GIMPLE Exception Handling, Prev: Tuple representation, Up: GIMPLE - -11.2 GIMPLE instruction set -=========================== - -The following table briefly describes the GIMPLE instruction set. - -Instruction High GIMPLE Low GIMPLE -'GIMPLE_ASM' x x -'GIMPLE_ASSIGN' x x -'GIMPLE_BIND' x -'GIMPLE_CALL' x x -'GIMPLE_CATCH' x -'GIMPLE_COND' x x -'GIMPLE_DEBUG' x x -'GIMPLE_EH_FILTER' x -'GIMPLE_GOTO' x x -'GIMPLE_LABEL' x x -'GIMPLE_NOP' x x -'GIMPLE_OMP_ATOMIC_LOAD' x x -'GIMPLE_OMP_ATOMIC_STORE' x x -'GIMPLE_OMP_CONTINUE' x x -'GIMPLE_OMP_CRITICAL' x x -'GIMPLE_OMP_FOR' x x -'GIMPLE_OMP_MASTER' x x -'GIMPLE_OMP_ORDERED' x x -'GIMPLE_OMP_PARALLEL' x x -'GIMPLE_OMP_RETURN' x x -'GIMPLE_OMP_SECTION' x x -'GIMPLE_OMP_SECTIONS' x x -'GIMPLE_OMP_SECTIONS_SWITCH' x x -'GIMPLE_OMP_SINGLE' x x -'GIMPLE_PHI' x -'GIMPLE_RESX' x -'GIMPLE_RETURN' x x -'GIMPLE_SWITCH' x x -'GIMPLE_TRY' x - - -File: gccint.info, Node: GIMPLE Exception Handling, Next: Temporaries, Prev: GIMPLE instruction set, Up: GIMPLE - -11.3 Exception Handling -======================= - -Other exception handling constructs are represented using -'GIMPLE_TRY_CATCH'. 'GIMPLE_TRY_CATCH' 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 'GIMPLE_TRY_CATCH' is checked. The second operand may have the -following forms: - - 1. A sequence of statements to execute. When an exception occurs, - these statements are executed, and then the exception is rethrown. - - 2. A sequence of 'GIMPLE_CATCH' statements. Each 'GIMPLE_CATCH' 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 'GIMPLE_TRY_CATCH'. - - 3. A 'GIMPLE_EH_FILTER' statement. 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. - - 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 'goto's, magic labels, and EH regions. -Continuing to unwind at the end of a cleanup is represented with a -'GIMPLE_RESX'. - - -File: gccint.info, Node: Temporaries, Next: Operands, Prev: GIMPLE Exception Handling, Up: GIMPLE - -11.4 Temporaries -================ - -When gimplification encounters a subexpression that 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 'expression temporaries', and are -allocated using '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(1). Other temporaries can be allocated using -'get_initialized_tmp_var' or 'create_tmp_var'. - - Currently, an expression like 'a = b + 5' is not reduced any further. -We tried converting it to something like - T1 = b + 5; - a = T1; - 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. - - ---------- Footnotes ---------- - - (1) These restrictions are derived from those in Morgan 4.8. - - -File: gccint.info, Node: Operands, Next: Manipulating GIMPLE statements, Prev: Temporaries, Up: GIMPLE - -11.5 Operands -============= - -In general, expressions in GIMPLE consist of an operation and the -appropriate number of simple operands; these operands must either be a -GIMPLE rvalue ('is_gimple_val'), i.e. a constant or a register variable. -More complex operands are factored out into temporaries, so that - a = b + c + d - becomes - T1 = b + c; - a = T1 + d; - - The same rule holds for arguments to a 'GIMPLE_CALL'. - - The target of an assignment is usually a variable, but can also be a -'MEM_REF' or a compound lvalue as described below. - -* Menu: - -* Compound Expressions:: -* Compound Lvalues:: -* Conditional Expressions:: -* Logical Operators:: - - -File: gccint.info, Node: Compound Expressions, Next: Compound Lvalues, Up: Operands - -11.5.1 Compound Expressions ---------------------------- - -The left-hand side of a C comma expression is simply moved into a -separate statement. - - -File: gccint.info, Node: Compound Lvalues, Next: Conditional Expressions, Prev: Compound Expressions, Up: Operands - -11.5.2 Compound Lvalues ------------------------ - -Currently compound lvalues involving array and structure field -references are not broken down; an expression like '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 - - T1 = &a.b; - T1[2] = 42; - - alias analysis would not remember that the reference to 'T1[2]' came by -way of 'a.b', so it would think that the assignment could alias another -member of 'a'; this broke 'struct-alias-1.c'. Future optimizer -improvements may make this limitation unnecessary. - - -File: gccint.info, Node: Conditional Expressions, Next: Logical Operators, Prev: Compound Lvalues, Up: Operands - -11.5.3 Conditional Expressions ------------------------------- - -A C '?:' expression is converted into an 'if' statement with each branch -assigning to the same temporary. So, - - a = b ? c : d; - becomes - if (b == 1) - T1 = c; - else - T1 = d; - a = T1; - - The GIMPLE level if-conversion pass re-introduces '?:' expression, if -appropriate. It is used to vectorize loops with conditions using vector -conditional operations. - - Note that in GIMPLE, 'if' statements are represented using -'GIMPLE_COND', as described below. - - -File: gccint.info, Node: Logical Operators, Prev: Conditional Expressions, Up: Operands - -11.5.4 Logical Operators ------------------------- - -Except when they appear in the condition operand of a 'GIMPLE_COND', -logical 'and' and 'or' operators are simplified as follows: 'a = b && c' -becomes - - T1 = (bool)b; - if (T1 == true) - T1 = (bool)c; - a = T1; - - Note that 'T1' in this example cannot be an expression temporary, -because it has two different assignments. - -11.5.5 Manipulating operands ----------------------------- - -All gimple operands are of type 'tree'. But only certain types of trees -are allowed to be used as operand tuples. Basic validation is -controlled by the function 'get_gimple_rhs_class', which given a tree -code, returns an 'enum' with the following values of type 'enum -gimple_rhs_class' - - * 'GIMPLE_INVALID_RHS' The tree cannot be used as a GIMPLE operand. - - * 'GIMPLE_TERNARY_RHS' The tree is a valid GIMPLE ternary operation. - - * 'GIMPLE_BINARY_RHS' The tree is a valid GIMPLE binary operation. - - * 'GIMPLE_UNARY_RHS' The tree is a valid GIMPLE unary operation. - - * 'GIMPLE_SINGLE_RHS' The tree is a single object, that cannot be - split into simpler operands (for instance, 'SSA_NAME', 'VAR_DECL', - 'COMPONENT_REF', etc). - - This operand class also acts as an escape hatch for tree nodes that - may be flattened out into the operand vector, but would need more - than two slots on the RHS. For instance, a 'COND_EXPR' expression - of the form '(a op b) ? x : y' could be flattened out on the - operand vector using 4 slots, but it would also require additional - processing to distinguish 'c = a op b' from 'c = a op b ? x : y'. - Something similar occurs with 'ASSERT_EXPR'. In time, these - special case tree expressions should be flattened into the operand - vector. - - For tree nodes in the categories 'GIMPLE_TERNARY_RHS', -'GIMPLE_BINARY_RHS' and 'GIMPLE_UNARY_RHS', they cannot be stored inside -tuples directly. They first need to be flattened and separated into -individual components. For instance, given the GENERIC expression - - a = b + c - - its tree representation is: - - MODIFY_EXPR <VAR_DECL <a>, PLUS_EXPR <VAR_DECL <b>, VAR_DECL <c>>> - - In this case, the GIMPLE form for this statement is logically identical -to its GENERIC form but in GIMPLE, the 'PLUS_EXPR' on the RHS of the -assignment is not represented as a tree, instead the two operands are -taken out of the 'PLUS_EXPR' sub-tree and flattened into the GIMPLE -tuple as follows: - - GIMPLE_ASSIGN <PLUS_EXPR, VAR_DECL <a>, VAR_DECL <b>, VAR_DECL <c>> - -11.5.6 Operand vector allocation --------------------------------- - -The operand vector is stored at the bottom of the three tuple structures -that accept operands. This means, that depending on the code of a given -statement, its operand vector will be at different offsets from the base -of the structure. To access tuple operands use the following accessors - - -- GIMPLE function: unsigned gimple_num_ops (gimple g) - Returns the number of operands in statement G. - - -- GIMPLE function: tree gimple_op (gimple g, unsigned i) - Returns operand 'I' from statement 'G'. - - -- GIMPLE function: tree * gimple_ops (gimple g) - Returns a pointer into the operand vector for statement 'G'. This - is computed using an internal table called 'gimple_ops_offset_'[]. - This table is indexed by the gimple code of 'G'. - - When the compiler is built, this table is filled-in using the sizes - of the structures used by each statement code defined in - gimple.def. Since the operand vector is at the bottom of the - structure, for a gimple code 'C' the offset is computed as sizeof - (struct-of 'C') - sizeof (tree). - - This mechanism adds one memory indirection to every access when - using 'gimple_op'(), if this becomes a bottleneck, a pass can - choose to memoize the result from 'gimple_ops'() and use that to - access the operands. - -11.5.7 Operand validation -------------------------- - -When adding a new operand to a gimple statement, the operand will be -validated according to what each tuple accepts in its operand vector. -These predicates are called by the 'gimple_NAME_set_...()'. Each tuple -will use one of the following predicates (Note, this list is not -exhaustive): - - -- GIMPLE function: bool is_gimple_val (tree t) - Returns true if t is a "GIMPLE value", which are all the - non-addressable stack variables (variables for which - 'is_gimple_reg' returns true) and constants (expressions for which - 'is_gimple_min_invariant' returns true). - - -- GIMPLE function: bool is_gimple_addressable (tree t) - Returns true if t is a symbol or memory reference whose address can - be taken. - - -- GIMPLE function: bool is_gimple_asm_val (tree t) - Similar to 'is_gimple_val' but it also accepts hard registers. - - -- GIMPLE function: bool is_gimple_call_addr (tree t) - Return true if t is a valid expression to use as the function - called by a 'GIMPLE_CALL'. - - -- GIMPLE function: bool is_gimple_mem_ref_addr (tree t) - Return true if t is a valid expression to use as first operand of a - 'MEM_REF' expression. - - -- GIMPLE function: bool is_gimple_constant (tree t) - Return true if t is a valid gimple constant. - - -- GIMPLE function: bool is_gimple_min_invariant (tree t) - Return true if t is a valid minimal invariant. This is different - from constants, in that the specific value of t may not be known at - compile time, but it is known that it doesn't change (e.g., the - address of a function local variable). - - -- GIMPLE function: bool is_gimple_ip_invariant (tree t) - Return true if t is an interprocedural invariant. This means that - t is a valid invariant in all functions (e.g. it can be an address - of a global variable but not of a local one). - - -- GIMPLE function: bool is_gimple_ip_invariant_address (tree t) - Return true if t is an 'ADDR_EXPR' that does not change once the - program is running (and which is valid in all functions). - -11.5.8 Statement validation ---------------------------- - - -- GIMPLE function: bool is_gimple_assign (gimple g) - Return true if the code of g is 'GIMPLE_ASSIGN'. - - -- GIMPLE function: bool is_gimple_call (gimple g) - Return true if the code of g is 'GIMPLE_CALL'. - - -- GIMPLE function: bool is_gimple_debug (gimple g) - Return true if the code of g is 'GIMPLE_DEBUG'. - - -- GIMPLE function: bool gimple_assign_cast_p (gimple g) - Return true if g is a 'GIMPLE_ASSIGN' that performs a type cast - operation. - - -- GIMPLE function: bool gimple_debug_bind_p (gimple g) - Return true if g is a 'GIMPLE_DEBUG' that binds the value of an - expression to a variable. - - -- GIMPLE function: bool is_gimple_omp (gimple g) - Return true if g is any of the OpenMP codes. - - -File: gccint.info, Node: Manipulating GIMPLE statements, Next: Tuple specific accessors, Prev: Operands, Up: GIMPLE - -11.6 Manipulating GIMPLE statements -=================================== - -This section documents all the functions available to handle each of the -GIMPLE instructions. - -11.6.1 Common accessors ------------------------ - -The following are common accessors for gimple statements. - - -- GIMPLE function: enum gimple_code gimple_code (gimple g) - Return the code for statement 'G'. - - -- GIMPLE function: basic_block gimple_bb (gimple g) - Return the basic block to which statement 'G' belongs to. - - -- GIMPLE function: tree gimple_block (gimple g) - Return the lexical scope block holding statement 'G'. - - -- GIMPLE function: tree gimple_expr_type (gimple stmt) - Return the type of the main expression computed by 'STMT'. Return - 'void_type_node' if 'STMT' computes nothing. This will only return - something meaningful for 'GIMPLE_ASSIGN', 'GIMPLE_COND' and - 'GIMPLE_CALL'. For all other tuple codes, it will return - 'void_type_node'. - - -- GIMPLE function: enum tree_code gimple_expr_code (gimple stmt) - Return the tree code for the expression computed by 'STMT'. This - is only meaningful for 'GIMPLE_CALL', 'GIMPLE_ASSIGN' and - 'GIMPLE_COND'. If 'STMT' is 'GIMPLE_CALL', it will return - 'CALL_EXPR'. For 'GIMPLE_COND', it returns the code of the - comparison predicate. For 'GIMPLE_ASSIGN' it returns the code of - the operation performed by the 'RHS' of the assignment. - - -- GIMPLE function: void gimple_set_block (gimple g, tree block) - Set the lexical scope block of 'G' to 'BLOCK'. - - -- GIMPLE function: location_t gimple_locus (gimple g) - Return locus information for statement 'G'. - - -- GIMPLE function: void gimple_set_locus (gimple g, location_t locus) - Set locus information for statement 'G'. - - -- GIMPLE function: bool gimple_locus_empty_p (gimple g) - Return true if 'G' does not have locus information. - - -- GIMPLE function: bool gimple_no_warning_p (gimple stmt) - Return true if no warnings should be emitted for statement 'STMT'. - - -- GIMPLE function: void gimple_set_visited (gimple stmt, bool - visited_p) - Set the visited status on statement 'STMT' to 'VISITED_P'. - - -- GIMPLE function: bool gimple_visited_p (gimple stmt) - Return the visited status on statement 'STMT'. - - -- GIMPLE function: void gimple_set_plf (gimple stmt, enum plf_mask - plf, bool val_p) - Set pass local flag 'PLF' on statement 'STMT' to 'VAL_P'. - - -- GIMPLE function: unsigned int gimple_plf (gimple stmt, enum plf_mask - plf) - Return the value of pass local flag 'PLF' on statement 'STMT'. - - -- GIMPLE function: bool gimple_has_ops (gimple g) - Return true if statement 'G' has register or memory operands. - - -- GIMPLE function: bool gimple_has_mem_ops (gimple g) - Return true if statement 'G' has memory operands. - - -- GIMPLE function: unsigned gimple_num_ops (gimple g) - Return the number of operands for statement 'G'. - - -- GIMPLE function: tree * gimple_ops (gimple g) - Return the array of operands for statement 'G'. - - -- GIMPLE function: tree gimple_op (gimple g, unsigned i) - Return operand 'I' for statement 'G'. - - -- GIMPLE function: tree * gimple_op_ptr (gimple g, unsigned i) - Return a pointer to operand 'I' for statement 'G'. - - -- GIMPLE function: void gimple_set_op (gimple g, unsigned i, tree op) - Set operand 'I' of statement 'G' to 'OP'. - - -- GIMPLE function: bitmap gimple_addresses_taken (gimple stmt) - Return the set of symbols that have had their address taken by - 'STMT'. - - -- GIMPLE function: struct def_optype_d * gimple_def_ops (gimple g) - Return the set of 'DEF' operands for statement 'G'. - - -- GIMPLE function: void gimple_set_def_ops (gimple g, struct - def_optype_d *def) - Set 'DEF' to be the set of 'DEF' operands for statement 'G'. - - -- GIMPLE function: struct use_optype_d * gimple_use_ops (gimple g) - Return the set of 'USE' operands for statement 'G'. - - -- GIMPLE function: void gimple_set_use_ops (gimple g, struct - use_optype_d *use) - Set 'USE' to be the set of 'USE' operands for statement 'G'. - - -- GIMPLE function: struct voptype_d * gimple_vuse_ops (gimple g) - Return the set of 'VUSE' operands for statement 'G'. - - -- GIMPLE function: void gimple_set_vuse_ops (gimple g, struct - voptype_d *ops) - Set 'OPS' to be the set of 'VUSE' operands for statement 'G'. - - -- GIMPLE function: struct voptype_d * gimple_vdef_ops (gimple g) - Return the set of 'VDEF' operands for statement 'G'. - - -- GIMPLE function: void gimple_set_vdef_ops (gimple g, struct - voptype_d *ops) - Set 'OPS' to be the set of 'VDEF' operands for statement 'G'. - - -- GIMPLE function: bitmap gimple_loaded_syms (gimple g) - Return the set of symbols loaded by statement 'G'. Each element of - the set is the 'DECL_UID' of the corresponding symbol. - - -- GIMPLE function: bitmap gimple_stored_syms (gimple g) - Return the set of symbols stored by statement 'G'. Each element of - the set is the 'DECL_UID' of the corresponding symbol. - - -- GIMPLE function: bool gimple_modified_p (gimple g) - Return true if statement 'G' has operands and the modified field - has been set. - - -- GIMPLE function: bool gimple_has_volatile_ops (gimple stmt) - Return true if statement 'STMT' contains volatile operands. - - -- GIMPLE function: void gimple_set_has_volatile_ops (gimple stmt, bool - volatilep) - Return true if statement 'STMT' contains volatile operands. - - -- GIMPLE function: void update_stmt (gimple s) - Mark statement 'S' as modified, and update it. - - -- GIMPLE function: void update_stmt_if_modified (gimple s) - Update statement 'S' if it has been marked modified. - - -- GIMPLE function: gimple gimple_copy (gimple stmt) - Return a deep copy of statement 'STMT'. - - -File: gccint.info, Node: Tuple specific accessors, Next: GIMPLE sequences, Prev: Manipulating GIMPLE statements, Up: GIMPLE - -11.7 Tuple specific accessors -============================= - -* Menu: - -* 'GIMPLE_ASM':: -* 'GIMPLE_ASSIGN':: -* 'GIMPLE_BIND':: -* 'GIMPLE_CALL':: -* 'GIMPLE_CATCH':: -* 'GIMPLE_COND':: -* 'GIMPLE_DEBUG':: -* 'GIMPLE_EH_FILTER':: -* 'GIMPLE_LABEL':: -* 'GIMPLE_NOP':: -* 'GIMPLE_OMP_ATOMIC_LOAD':: -* 'GIMPLE_OMP_ATOMIC_STORE':: -* 'GIMPLE_OMP_CONTINUE':: -* 'GIMPLE_OMP_CRITICAL':: -* 'GIMPLE_OMP_FOR':: -* 'GIMPLE_OMP_MASTER':: -* 'GIMPLE_OMP_ORDERED':: -* 'GIMPLE_OMP_PARALLEL':: -* 'GIMPLE_OMP_RETURN':: -* 'GIMPLE_OMP_SECTION':: -* 'GIMPLE_OMP_SECTIONS':: -* 'GIMPLE_OMP_SINGLE':: -* 'GIMPLE_PHI':: -* 'GIMPLE_RESX':: -* 'GIMPLE_RETURN':: -* 'GIMPLE_SWITCH':: -* 'GIMPLE_TRY':: -* 'GIMPLE_WITH_CLEANUP_EXPR':: - - -File: gccint.info, Node: 'GIMPLE_ASM', Next: 'GIMPLE_ASSIGN', Up: Tuple specific accessors - -11.7.1 'GIMPLE_ASM' -------------------- - - -- GIMPLE function: gimple gimple_build_asm (const char *string, - ninputs, noutputs, nclobbers, ...) - Build a 'GIMPLE_ASM' statement. This statement is used for - building in-line assembly constructs. 'STRING' is the assembly - code. 'NINPUT' is the number of register inputs. 'NOUTPUT' is the - number of register outputs. 'NCLOBBERS' is the number of clobbered - registers. The rest of the arguments trees for each input, output, - and clobbered registers. - - -- GIMPLE function: gimple gimple_build_asm_vec (const char *, - VEC(tree,gc) *, VEC(tree,gc) *, VEC(tree,gc) *) - Identical to gimple_build_asm, but the arguments are passed in - VECs. - - -- GIMPLE function: unsigned gimple_asm_ninputs (gimple g) - Return the number of input operands for 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: unsigned gimple_asm_noutputs (gimple g) - Return the number of output operands for 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: unsigned gimple_asm_nclobbers (gimple g) - Return the number of clobber operands for 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: tree gimple_asm_input_op (gimple g, unsigned index) - Return input operand 'INDEX' of 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: void gimple_asm_set_input_op (gimple g, unsigned - index, tree in_op) - Set 'IN_OP' to be input operand 'INDEX' in 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: tree gimple_asm_output_op (gimple g, unsigned - index) - Return output operand 'INDEX' of 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: void gimple_asm_set_output_op (gimple g, unsigned - index, tree out_op) - Set 'OUT_OP' to be output operand 'INDEX' in 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: tree gimple_asm_clobber_op (gimple g, unsigned - index) - Return clobber operand 'INDEX' of 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: void gimple_asm_set_clobber_op (gimple g, unsigned - index, tree clobber_op) - Set 'CLOBBER_OP' to be clobber operand 'INDEX' in 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: const char * gimple_asm_string (gimple g) - Return the string representing the assembly instruction in - 'GIMPLE_ASM' 'G'. - - -- GIMPLE function: bool gimple_asm_volatile_p (gimple g) - Return true if 'G' is an asm statement marked volatile. - - -- GIMPLE function: void gimple_asm_set_volatile (gimple g) - Mark asm statement 'G' as volatile. - - -File: gccint.info, Node: 'GIMPLE_ASSIGN', Next: 'GIMPLE_BIND', Prev: 'GIMPLE_ASM', Up: Tuple specific accessors - -11.7.2 'GIMPLE_ASSIGN' ----------------------- - - -- GIMPLE function: gimple gimple_build_assign (tree lhs, tree rhs) - Build a 'GIMPLE_ASSIGN' statement. The left-hand side is an lvalue - passed in lhs. The right-hand side can be either a unary or binary - tree expression. The expression tree rhs will be flattened and its - operands assigned to the corresponding operand slots in the new - statement. This function is useful when you already have a tree - expression that you want to convert into a tuple. However, try to - avoid building expression trees for the sole purpose of calling - this function. If you already have the operands in separate trees, - it is better to use 'gimple_build_assign_with_ops'. - - -- GIMPLE function: gimple gimplify_assign (tree dst, tree src, - gimple_seq *seq_p) - Build a new 'GIMPLE_ASSIGN' tuple and append it to the end of - '*SEQ_P'. - - 'DST'/'SRC' are the destination and source respectively. You can pass -ungimplified trees in 'DST' or 'SRC', in which case they will be -converted to a gimple operand if necessary. - - This function returns the newly created 'GIMPLE_ASSIGN' tuple. - - -- GIMPLE function: gimple gimple_build_assign_with_ops (enum tree_code - subcode, tree lhs, tree op1, tree op2) - This function is similar to 'gimple_build_assign', but is used to - build a 'GIMPLE_ASSIGN' statement when the operands of the - right-hand side of the assignment are already split into different - operands. - - The left-hand side is an lvalue passed in lhs. Subcode is the - 'tree_code' for the right-hand side of the assignment. Op1 and op2 - are the operands. If op2 is null, subcode must be a 'tree_code' - for a unary expression. - - -- GIMPLE function: enum tree_code gimple_assign_rhs_code (gimple g) - Return the code of the expression computed on the 'RHS' of - assignment statement 'G'. - - -- GIMPLE function: enum gimple_rhs_class gimple_assign_rhs_class - (gimple g) - Return the gimple rhs class of the code for the expression computed - on the rhs of assignment statement 'G'. This will never return - 'GIMPLE_INVALID_RHS'. - - -- GIMPLE function: tree gimple_assign_lhs (gimple g) - Return the 'LHS' of assignment statement 'G'. - - -- GIMPLE function: tree * gimple_assign_lhs_ptr (gimple g) - Return a pointer to the 'LHS' of assignment statement 'G'. - - -- GIMPLE function: tree gimple_assign_rhs1 (gimple g) - Return the first operand on the 'RHS' of assignment statement 'G'. - - -- GIMPLE function: tree * gimple_assign_rhs1_ptr (gimple g) - Return the address of the first operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: tree gimple_assign_rhs2 (gimple g) - Return the second operand on the 'RHS' of assignment statement 'G'. - - -- GIMPLE function: tree * gimple_assign_rhs2_ptr (gimple g) - Return the address of the second operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: tree gimple_assign_rhs3 (gimple g) - Return the third operand on the 'RHS' of assignment statement 'G'. - - -- GIMPLE function: tree * gimple_assign_rhs3_ptr (gimple g) - Return the address of the third operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: void gimple_assign_set_lhs (gimple g, tree lhs) - Set 'LHS' to be the 'LHS' operand of assignment statement 'G'. - - -- GIMPLE function: void gimple_assign_set_rhs1 (gimple g, tree rhs) - Set 'RHS' to be the first operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: void gimple_assign_set_rhs2 (gimple g, tree rhs) - Set 'RHS' to be the second operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: void gimple_assign_set_rhs3 (gimple g, tree rhs) - Set 'RHS' to be the third operand on the 'RHS' of assignment - statement 'G'. - - -- GIMPLE function: bool gimple_assign_cast_p (gimple s) - Return true if 'S' is a type-cast assignment. - - -File: gccint.info, Node: 'GIMPLE_BIND', Next: 'GIMPLE_CALL', Prev: 'GIMPLE_ASSIGN', Up: Tuple specific accessors - -11.7.3 'GIMPLE_BIND' --------------------- - - -- GIMPLE function: gimple gimple_build_bind (tree vars, gimple_seq - body) - Build a 'GIMPLE_BIND' statement with a list of variables in 'VARS' - and a body of statements in sequence 'BODY'. - - -- GIMPLE function: tree gimple_bind_vars (gimple g) - Return the variables declared in the 'GIMPLE_BIND' statement 'G'. - - -- GIMPLE function: void gimple_bind_set_vars (gimple g, tree vars) - Set 'VARS' to be the set of variables declared in the 'GIMPLE_BIND' - statement 'G'. - - -- GIMPLE function: void gimple_bind_append_vars (gimple g, tree vars) - Append 'VARS' to the set of variables declared in the 'GIMPLE_BIND' - statement 'G'. - - -- GIMPLE function: gimple_seq gimple_bind_body (gimple g) - Return the GIMPLE sequence contained in the 'GIMPLE_BIND' statement - 'G'. - - -- GIMPLE function: void gimple_bind_set_body (gimple g, gimple_seq - seq) - Set 'SEQ' to be sequence contained in the 'GIMPLE_BIND' statement - 'G'. - - -- GIMPLE function: void gimple_bind_add_stmt (gimple gs, gimple stmt) - Append a statement to the end of a 'GIMPLE_BIND''s body. - - -- GIMPLE function: void gimple_bind_add_seq (gimple gs, gimple_seq - seq) - Append a sequence of statements to the end of a 'GIMPLE_BIND''s - body. - - -- GIMPLE function: tree gimple_bind_block (gimple g) - Return the 'TREE_BLOCK' node associated with 'GIMPLE_BIND' - statement 'G'. This is analogous to the 'BIND_EXPR_BLOCK' field in - trees. - - -- GIMPLE function: void gimple_bind_set_block (gimple g, tree block) - Set 'BLOCK' to be the 'TREE_BLOCK' node associated with - 'GIMPLE_BIND' statement 'G'. - - -File: gccint.info, Node: 'GIMPLE_CALL', Next: 'GIMPLE_CATCH', Prev: 'GIMPLE_BIND', Up: Tuple specific accessors - -11.7.4 'GIMPLE_CALL' --------------------- - - -- GIMPLE function: gimple gimple_build_call (tree fn, unsigned nargs, - ...) - Build a 'GIMPLE_CALL' statement to function 'FN'. The argument - 'FN' must be either a 'FUNCTION_DECL' or a gimple call address as - determined by 'is_gimple_call_addr'. 'NARGS' are the number of - arguments. The rest of the arguments follow the argument 'NARGS', - and must be trees that are valid as rvalues in gimple (i.e., each - operand is validated with 'is_gimple_operand'). - - -- GIMPLE function: gimple gimple_build_call_from_tree (tree call_expr) - Build a 'GIMPLE_CALL' from a 'CALL_EXPR' node. The arguments and - the function are taken from the expression directly. This routine - assumes that 'call_expr' is already in GIMPLE form. That is, its - operands are GIMPLE values and the function call needs no further - simplification. All the call flags in 'call_expr' are copied over - to the new 'GIMPLE_CALL'. - - -- GIMPLE function: gimple gimple_build_call_vec (tree fn, 'VEC'(tree, - heap) *args) - Identical to 'gimple_build_call' but the arguments are stored in a - 'VEC'(). - - -- GIMPLE function: tree gimple_call_lhs (gimple g) - Return the 'LHS' of call statement 'G'. - - -- GIMPLE function: tree * gimple_call_lhs_ptr (gimple g) - Return a pointer to the 'LHS' of call statement 'G'. - - -- GIMPLE function: void gimple_call_set_lhs (gimple g, tree lhs) - Set 'LHS' to be the 'LHS' operand of call statement 'G'. - - -- GIMPLE function: tree gimple_call_fn (gimple g) - Return the tree node representing the function called by call - statement 'G'. - - -- GIMPLE function: void gimple_call_set_fn (gimple g, tree fn) - Set 'FN' to be the function called by call statement 'G'. This has - to be a gimple value specifying the address of the called function. - - -- GIMPLE function: tree gimple_call_fndecl (gimple g) - If a given 'GIMPLE_CALL''s callee is a 'FUNCTION_DECL', return it. - Otherwise return 'NULL'. This function is analogous to - 'get_callee_fndecl' in 'GENERIC'. - - -- GIMPLE function: tree gimple_call_set_fndecl (gimple g, tree fndecl) - Set the called function to 'FNDECL'. - - -- GIMPLE function: tree gimple_call_return_type (gimple g) - Return the type returned by call statement 'G'. - - -- GIMPLE function: tree gimple_call_chain (gimple g) - Return the static chain for call statement 'G'. - - -- GIMPLE function: void gimple_call_set_chain (gimple g, tree chain) - Set 'CHAIN' to be the static chain for call statement 'G'. - - -- GIMPLE function: unsigned gimple_call_num_args (gimple g) - Return the number of arguments used by call statement 'G'. - - -- GIMPLE function: tree gimple_call_arg (gimple g, unsigned index) - Return the argument at position 'INDEX' for call statement 'G'. - The first argument is 0. - - -- GIMPLE function: tree * gimple_call_arg_ptr (gimple g, unsigned - index) - Return a pointer to the argument at position 'INDEX' for call - statement 'G'. - - -- GIMPLE function: void gimple_call_set_arg (gimple g, unsigned index, - tree arg) - Set 'ARG' to be the argument at position 'INDEX' for call statement - 'G'. - - -- GIMPLE function: void gimple_call_set_tail (gimple s) - Mark call statement 'S' as being a tail call (i.e., a call just - before the exit of a function). These calls are candidate for tail - call optimization. - - -- GIMPLE function: bool gimple_call_tail_p (gimple s) - Return true if 'GIMPLE_CALL' 'S' is marked as a tail call. - - -- GIMPLE function: void gimple_call_mark_uninlinable (gimple s) - Mark 'GIMPLE_CALL' 'S' as being uninlinable. - - -- GIMPLE function: bool gimple_call_cannot_inline_p (gimple s) - Return true if 'GIMPLE_CALL' 'S' cannot be inlined. - - -- GIMPLE function: bool gimple_call_noreturn_p (gimple s) - Return true if 'S' is a noreturn call. - - -- GIMPLE function: gimple gimple_call_copy_skip_args (gimple stmt, - bitmap args_to_skip) - Build a 'GIMPLE_CALL' identical to 'STMT' but skipping the - arguments in the positions marked by the set 'ARGS_TO_SKIP'. - - -File: gccint.info, Node: 'GIMPLE_CATCH', Next: 'GIMPLE_COND', Prev: 'GIMPLE_CALL', Up: Tuple specific accessors - -11.7.5 'GIMPLE_CATCH' ---------------------- - - -- GIMPLE function: gimple gimple_build_catch (tree types, gimple_seq - handler) - Build a 'GIMPLE_CATCH' statement. 'TYPES' are the tree types this - catch handles. 'HANDLER' is a sequence of statements with the code - for the handler. - - -- GIMPLE function: tree gimple_catch_types (gimple g) - Return the types handled by 'GIMPLE_CATCH' statement 'G'. - - -- GIMPLE function: tree * gimple_catch_types_ptr (gimple g) - Return a pointer to the types handled by 'GIMPLE_CATCH' statement - 'G'. - - -- GIMPLE function: gimple_seq gimple_catch_handler (gimple g) - Return the GIMPLE sequence representing the body of the handler of - 'GIMPLE_CATCH' statement 'G'. - - -- GIMPLE function: void gimple_catch_set_types (gimple g, tree t) - Set 'T' to be the set of types handled by 'GIMPLE_CATCH' 'G'. - - -- GIMPLE function: void gimple_catch_set_handler (gimple g, gimple_seq - handler) - Set 'HANDLER' to be the body of 'GIMPLE_CATCH' 'G'. - - -File: gccint.info, Node: 'GIMPLE_COND', Next: 'GIMPLE_DEBUG', Prev: 'GIMPLE_CATCH', Up: Tuple specific accessors - -11.7.6 'GIMPLE_COND' --------------------- - - -- GIMPLE function: gimple gimple_build_cond (enum tree_code pred_code, - tree lhs, tree rhs, tree t_label, tree f_label) - Build a 'GIMPLE_COND' statement. 'A' 'GIMPLE_COND' statement - compares 'LHS' and 'RHS' and if the condition in 'PRED_CODE' is - true, jump to the label in 't_label', otherwise jump to the label - in 'f_label'. 'PRED_CODE' are relational operator tree codes like - 'EQ_EXPR', 'LT_EXPR', 'LE_EXPR', 'NE_EXPR', etc. - - -- GIMPLE function: gimple gimple_build_cond_from_tree (tree cond, tree - t_label, tree f_label) - Build a 'GIMPLE_COND' statement from the conditional expression - tree 'COND'. 'T_LABEL' and 'F_LABEL' are as in - 'gimple_build_cond'. - - -- GIMPLE function: enum tree_code gimple_cond_code (gimple g) - Return the code of the predicate computed by conditional statement - 'G'. - - -- GIMPLE function: void gimple_cond_set_code (gimple g, enum tree_code - code) - Set 'CODE' to be the predicate code for the conditional statement - 'G'. - - -- GIMPLE function: tree gimple_cond_lhs (gimple g) - Return the 'LHS' of the predicate computed by conditional statement - 'G'. - - -- GIMPLE function: void gimple_cond_set_lhs (gimple g, tree lhs) - Set 'LHS' to be the 'LHS' operand of the predicate computed by - conditional statement 'G'. - - -- GIMPLE function: tree gimple_cond_rhs (gimple g) - Return the 'RHS' operand of the predicate computed by conditional - 'G'. - - -- GIMPLE function: void gimple_cond_set_rhs (gimple g, tree rhs) - Set 'RHS' to be the 'RHS' operand of the predicate computed by - conditional statement 'G'. - - -- GIMPLE function: tree gimple_cond_true_label (gimple g) - Return the label used by conditional statement 'G' when its - predicate evaluates to true. - - -- GIMPLE function: void gimple_cond_set_true_label (gimple g, tree - label) - Set 'LABEL' to be the label used by conditional statement 'G' when - its predicate evaluates to true. - - -- GIMPLE function: void gimple_cond_set_false_label (gimple g, tree - label) - Set 'LABEL' to be the label used by conditional statement 'G' when - its predicate evaluates to false. - - -- GIMPLE function: tree gimple_cond_false_label (gimple g) - Return the label used by conditional statement 'G' when its - predicate evaluates to false. - - -- GIMPLE function: void gimple_cond_make_false (gimple g) - Set the conditional 'COND_STMT' to be of the form 'if (1 == 0)'. - - -- GIMPLE function: void gimple_cond_make_true (gimple g) - Set the conditional 'COND_STMT' to be of the form 'if (1 == 1)'. - - -File: gccint.info, Node: 'GIMPLE_DEBUG', Next: 'GIMPLE_EH_FILTER', Prev: 'GIMPLE_COND', Up: Tuple specific accessors - -11.7.7 'GIMPLE_DEBUG' ---------------------- - - -- GIMPLE function: gimple gimple_build_debug_bind (tree var, tree - value, gimple stmt) - Build a 'GIMPLE_DEBUG' statement with 'GIMPLE_DEBUG_BIND' of - 'subcode'. The effect of this statement is to tell debug - information generation machinery that the value of user variable - 'var' is given by 'value' at that point, and to remain with that - value until 'var' runs out of scope, a dynamically-subsequent debug - bind statement overrides the binding, or conflicting values reach a - control flow merge point. Even if components of the 'value' - expression change afterwards, the variable is supposed to retain - the same value, though not necessarily the same location. - - It is expected that 'var' be most often a tree for automatic user - variables ('VAR_DECL' or 'PARM_DECL') that satisfy the requirements - for gimple registers, but it may also be a tree for a scalarized - component of a user variable ('ARRAY_REF', 'COMPONENT_REF'), or a - debug temporary ('DEBUG_EXPR_DECL'). - - As for 'value', it can be an arbitrary tree expression, but it is - recommended that it be in a suitable form for a gimple assignment - 'RHS'. It is not expected that user variables that could appear as - 'var' ever appear in 'value', because in the latter we'd have their - 'SSA_NAME's instead, but even if they were not in SSA form, user - variables appearing in 'value' are to be regarded as part of the - executable code space, whereas those in 'var' are to be regarded as - part of the source code space. There is no way to refer to the - value bound to a user variable within a 'value' expression. - - If 'value' is 'GIMPLE_DEBUG_BIND_NOVALUE', debug information - generation machinery is informed that the variable 'var' is - unbound, i.e., that its value is indeterminate, which sometimes - means it is really unavailable, and other times that the compiler - could not keep track of it. - - Block and location information for the newly-created stmt are taken - from 'stmt', if given. - - -- GIMPLE function: tree gimple_debug_bind_get_var (gimple stmt) - Return the user variable VAR that is bound at 'stmt'. - - -- GIMPLE function: tree gimple_debug_bind_get_value (gimple stmt) - Return the value expression that is bound to a user variable at - 'stmt'. - - -- GIMPLE function: tree * gimple_debug_bind_get_value_ptr (gimple - stmt) - Return a pointer to the value expression that is bound to a user - variable at 'stmt'. - - -- GIMPLE function: void gimple_debug_bind_set_var (gimple stmt, tree - var) - Modify the user variable bound at 'stmt' to VAR. - - -- GIMPLE function: void gimple_debug_bind_set_value (gimple stmt, tree - var) - Modify the value bound to the user variable bound at 'stmt' to - VALUE. - - -- GIMPLE function: void gimple_debug_bind_reset_value (gimple stmt) - Modify the value bound to the user variable bound at 'stmt' so that - the variable becomes unbound. - - -- GIMPLE function: bool gimple_debug_bind_has_value_p (gimple stmt) - Return 'TRUE' if 'stmt' binds a user variable to a value, and - 'FALSE' if it unbinds the variable. - - -File: gccint.info, Node: 'GIMPLE_EH_FILTER', Next: 'GIMPLE_LABEL', Prev: 'GIMPLE_DEBUG', Up: Tuple specific accessors - -11.7.8 'GIMPLE_EH_FILTER' -------------------------- - - -- GIMPLE function: gimple gimple_build_eh_filter (tree types, - gimple_seq failure) - Build a 'GIMPLE_EH_FILTER' statement. 'TYPES' are the filter's - types. 'FAILURE' is a sequence with the filter's failure action. - - -- GIMPLE function: tree gimple_eh_filter_types (gimple g) - Return the types handled by 'GIMPLE_EH_FILTER' statement 'G'. - - -- GIMPLE function: tree * gimple_eh_filter_types_ptr (gimple g) - Return a pointer to the types handled by 'GIMPLE_EH_FILTER' - statement 'G'. - - -- GIMPLE function: gimple_seq gimple_eh_filter_failure (gimple g) - Return the sequence of statement to execute when 'GIMPLE_EH_FILTER' - statement fails. - - -- GIMPLE function: void gimple_eh_filter_set_types (gimple g, tree - types) - Set 'TYPES' to be the set of types handled by 'GIMPLE_EH_FILTER' - 'G'. - - -- GIMPLE function: void gimple_eh_filter_set_failure (gimple g, - gimple_seq failure) - Set 'FAILURE' to be the sequence of statements to execute on - failure for 'GIMPLE_EH_FILTER' 'G'. - - -- GIMPLE function: bool gimple_eh_filter_must_not_throw (gimple g) - Return the 'EH_FILTER_MUST_NOT_THROW' flag. - - -- GIMPLE function: void gimple_eh_filter_set_must_not_throw (gimple g, - bool mntp) - Set the 'EH_FILTER_MUST_NOT_THROW' flag. - - -File: gccint.info, Node: 'GIMPLE_LABEL', Next: 'GIMPLE_NOP', Prev: 'GIMPLE_EH_FILTER', Up: Tuple specific accessors - -11.7.9 'GIMPLE_LABEL' ---------------------- - - -- GIMPLE function: gimple gimple_build_label (tree label) - Build a 'GIMPLE_LABEL' statement with corresponding to the tree - label, 'LABEL'. - - -- GIMPLE function: tree gimple_label_label (gimple g) - Return the 'LABEL_DECL' node used by 'GIMPLE_LABEL' statement 'G'. - - -- GIMPLE function: void gimple_label_set_label (gimple g, tree label) - Set 'LABEL' to be the 'LABEL_DECL' node used by 'GIMPLE_LABEL' - statement 'G'. - - -- GIMPLE function: gimple gimple_build_goto (tree dest) - Build a 'GIMPLE_GOTO' statement to label 'DEST'. - - -- GIMPLE function: tree gimple_goto_dest (gimple g) - Return the destination of the unconditional jump 'G'. - - -- GIMPLE function: void gimple_goto_set_dest (gimple g, tree dest) - Set 'DEST' to be the destination of the unconditional jump 'G'. - - -File: gccint.info, Node: 'GIMPLE_NOP', Next: 'GIMPLE_OMP_ATOMIC_LOAD', Prev: 'GIMPLE_LABEL', Up: Tuple specific accessors - -11.7.10 'GIMPLE_NOP' --------------------- - - -- GIMPLE function: gimple gimple_build_nop (void) - Build a 'GIMPLE_NOP' statement. - - -- GIMPLE function: bool gimple_nop_p (gimple g) - Returns 'TRUE' if statement 'G' is a 'GIMPLE_NOP'. - - -File: gccint.info, Node: 'GIMPLE_OMP_ATOMIC_LOAD', Next: 'GIMPLE_OMP_ATOMIC_STORE', Prev: 'GIMPLE_NOP', Up: Tuple specific accessors - -11.7.11 'GIMPLE_OMP_ATOMIC_LOAD' --------------------------------- - - -- GIMPLE function: gimple gimple_build_omp_atomic_load (tree lhs, tree - rhs) - Build a 'GIMPLE_OMP_ATOMIC_LOAD' statement. 'LHS' is the left-hand - side of the assignment. 'RHS' is the right-hand side of the - assignment. - - -- GIMPLE function: void gimple_omp_atomic_load_set_lhs (gimple g, tree - lhs) - Set the 'LHS' of an atomic load. - - -- GIMPLE function: tree gimple_omp_atomic_load_lhs (gimple g) - Get the 'LHS' of an atomic load. - - -- GIMPLE function: void gimple_omp_atomic_load_set_rhs (gimple g, tree - rhs) - Set the 'RHS' of an atomic set. - - -- GIMPLE function: tree gimple_omp_atomic_load_rhs (gimple g) - Get the 'RHS' of an atomic set. - - -File: gccint.info, Node: 'GIMPLE_OMP_ATOMIC_STORE', Next: 'GIMPLE_OMP_CONTINUE', Prev: 'GIMPLE_OMP_ATOMIC_LOAD', Up: Tuple specific accessors - -11.7.12 'GIMPLE_OMP_ATOMIC_STORE' ---------------------------------- - - -- GIMPLE function: gimple gimple_build_omp_atomic_store (tree val) - Build a 'GIMPLE_OMP_ATOMIC_STORE' statement. 'VAL' is the value to - be stored. - - -- GIMPLE function: void gimple_omp_atomic_store_set_val (gimple g, - tree val) - Set the value being stored in an atomic store. - - -- GIMPLE function: tree gimple_omp_atomic_store_val (gimple g) - Return the value being stored in an atomic store. - - -File: gccint.info, Node: 'GIMPLE_OMP_CONTINUE', Next: 'GIMPLE_OMP_CRITICAL', Prev: 'GIMPLE_OMP_ATOMIC_STORE', Up: Tuple specific accessors - -11.7.13 'GIMPLE_OMP_CONTINUE' ------------------------------ - - -- GIMPLE function: gimple gimple_build_omp_continue (tree control_def, - tree control_use) - Build a 'GIMPLE_OMP_CONTINUE' statement. 'CONTROL_DEF' is the - definition of the control variable. 'CONTROL_USE' is the use of - the control variable. - - -- GIMPLE function: tree gimple_omp_continue_control_def (gimple s) - Return the definition of the control variable on a - 'GIMPLE_OMP_CONTINUE' in 'S'. - - -- GIMPLE function: tree gimple_omp_continue_control_def_ptr (gimple s) - Same as above, but return the pointer. - - -- GIMPLE function: tree gimple_omp_continue_set_control_def (gimple s) - Set the control variable definition for a 'GIMPLE_OMP_CONTINUE' - statement in 'S'. - - -- GIMPLE function: tree gimple_omp_continue_control_use (gimple s) - Return the use of the control variable on a 'GIMPLE_OMP_CONTINUE' - in 'S'. - - -- GIMPLE function: tree gimple_omp_continue_control_use_ptr (gimple s) - Same as above, but return the pointer. - - -- GIMPLE function: tree gimple_omp_continue_set_control_use (gimple s) - Set the control variable use for a 'GIMPLE_OMP_CONTINUE' statement - in 'S'. - - -File: gccint.info, Node: 'GIMPLE_OMP_CRITICAL', Next: 'GIMPLE_OMP_FOR', Prev: 'GIMPLE_OMP_CONTINUE', Up: Tuple specific accessors - -11.7.14 'GIMPLE_OMP_CRITICAL' ------------------------------ - - -- GIMPLE function: gimple gimple_build_omp_critical (gimple_seq body, - tree name) - Build a 'GIMPLE_OMP_CRITICAL' statement. 'BODY' is the sequence of - statements for which only one thread can execute. 'NAME' is an - optional identifier for this critical block. - - -- GIMPLE function: tree gimple_omp_critical_name (gimple g) - Return the name associated with 'OMP_CRITICAL' statement 'G'. - - -- GIMPLE function: tree * gimple_omp_critical_name_ptr (gimple g) - Return a pointer to the name associated with 'OMP' critical - statement 'G'. - - -- GIMPLE function: void gimple_omp_critical_set_name (gimple g, tree - name) - Set 'NAME' to be the name associated with 'OMP' critical statement - 'G'. - - -File: gccint.info, Node: 'GIMPLE_OMP_FOR', Next: 'GIMPLE_OMP_MASTER', Prev: 'GIMPLE_OMP_CRITICAL', Up: Tuple specific accessors - -11.7.15 'GIMPLE_OMP_FOR' ------------------------- - - -- GIMPLE function: gimple gimple_build_omp_for (gimple_seq body, tree - clauses, tree index, tree initial, tree final, tree incr, - gimple_seq pre_body, enum tree_code omp_for_cond) - Build a 'GIMPLE_OMP_FOR' statement. 'BODY' is sequence of - statements inside the for loop. 'CLAUSES', are any of the 'OMP' - loop construct's clauses: private, firstprivate, lastprivate, - reductions, ordered, schedule, and nowait. 'PRE_BODY' is the - sequence of statements that are loop invariant. 'INDEX' is the - index variable. 'INITIAL' is the initial value of 'INDEX'. - 'FINAL' is final value of 'INDEX'. OMP_FOR_COND is the predicate - used to compare 'INDEX' and 'FINAL'. 'INCR' is the increment - expression. - - -- GIMPLE function: tree gimple_omp_for_clauses (gimple g) - Return the clauses associated with 'OMP_FOR' 'G'. - - -- GIMPLE function: tree * gimple_omp_for_clauses_ptr (gimple g) - Return a pointer to the 'OMP_FOR' 'G'. - - -- GIMPLE function: void gimple_omp_for_set_clauses (gimple g, tree - clauses) - Set 'CLAUSES' to be the list of clauses associated with 'OMP_FOR' - 'G'. - - -- GIMPLE function: tree gimple_omp_for_index (gimple g) - Return the index variable for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree * gimple_omp_for_index_ptr (gimple g) - Return a pointer to the index variable for 'OMP_FOR' 'G'. - - -- GIMPLE function: void gimple_omp_for_set_index (gimple g, tree - index) - Set 'INDEX' to be the index variable for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree gimple_omp_for_initial (gimple g) - Return the initial value for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree * gimple_omp_for_initial_ptr (gimple g) - Return a pointer to the initial value for 'OMP_FOR' 'G'. - - -- GIMPLE function: void gimple_omp_for_set_initial (gimple g, tree - initial) - Set 'INITIAL' to be the initial value for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree gimple_omp_for_final (gimple g) - Return the final value for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree * gimple_omp_for_final_ptr (gimple g) - turn a pointer to the final value for 'OMP_FOR' 'G'. - - -- GIMPLE function: void gimple_omp_for_set_final (gimple g, tree - final) - Set 'FINAL' to be the final value for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree gimple_omp_for_incr (gimple g) - Return the increment value for 'OMP_FOR' 'G'. - - -- GIMPLE function: tree * gimple_omp_for_incr_ptr (gimple g) - Return a pointer to the increment value for 'OMP_FOR' 'G'. - - -- GIMPLE function: void gimple_omp_for_set_incr (gimple g, tree incr) - Set 'INCR' to be the increment value for 'OMP_FOR' 'G'. - - -- GIMPLE function: gimple_seq gimple_omp_for_pre_body (gimple g) - Return the sequence of statements to execute before the 'OMP_FOR' - statement 'G' starts. - - -- GIMPLE function: void gimple_omp_for_set_pre_body (gimple g, - gimple_seq pre_body) - Set 'PRE_BODY' to be the sequence of statements to execute before - the 'OMP_FOR' statement 'G' starts. - - -- GIMPLE function: void gimple_omp_for_set_cond (gimple g, enum - tree_code cond) - Set 'COND' to be the condition code for 'OMP_FOR' 'G'. - - -- GIMPLE function: enum tree_code gimple_omp_for_cond (gimple g) - Return the condition code associated with 'OMP_FOR' 'G'. - - -File: gccint.info, Node: 'GIMPLE_OMP_MASTER', Next: 'GIMPLE_OMP_ORDERED', Prev: 'GIMPLE_OMP_FOR', Up: Tuple specific accessors - -11.7.16 'GIMPLE_OMP_MASTER' ---------------------------- - - -- GIMPLE function: gimple gimple_build_omp_master (gimple_seq body) - Build a 'GIMPLE_OMP_MASTER' statement. 'BODY' is the sequence of - statements to be executed by just the master. - - -File: gccint.info, Node: 'GIMPLE_OMP_ORDERED', Next: 'GIMPLE_OMP_PARALLEL', Prev: 'GIMPLE_OMP_MASTER', Up: Tuple specific accessors - -11.7.17 'GIMPLE_OMP_ORDERED' ----------------------------- - - -- GIMPLE function: gimple gimple_build_omp_ordered (gimple_seq body) - Build a 'GIMPLE_OMP_ORDERED' statement. - - 'BODY' is the sequence of statements inside a loop that will executed -in sequence. - - -File: gccint.info, Node: 'GIMPLE_OMP_PARALLEL', Next: 'GIMPLE_OMP_RETURN', Prev: 'GIMPLE_OMP_ORDERED', Up: Tuple specific accessors - -11.7.18 'GIMPLE_OMP_PARALLEL' ------------------------------ - - -- GIMPLE function: gimple gimple_build_omp_parallel (gimple_seq body, - tree clauses, tree child_fn, tree data_arg) - Build a 'GIMPLE_OMP_PARALLEL' statement. - - 'BODY' is sequence of statements which are executed in parallel. -'CLAUSES', are the 'OMP' parallel construct's clauses. 'CHILD_FN' is -the function created for the parallel threads to execute. 'DATA_ARG' -are the shared data argument(s). - - -- GIMPLE function: bool gimple_omp_parallel_combined_p (gimple g) - Return true if 'OMP' parallel statement 'G' has the - 'GF_OMP_PARALLEL_COMBINED' flag set. - - -- GIMPLE function: void gimple_omp_parallel_set_combined_p (gimple g) - Set the 'GF_OMP_PARALLEL_COMBINED' field in 'OMP' parallel - statement 'G'. - - -- GIMPLE function: gimple_seq gimple_omp_body (gimple g) - Return the body for the 'OMP' statement 'G'. - - -- GIMPLE function: void gimple_omp_set_body (gimple g, gimple_seq - body) - Set 'BODY' to be the body for the 'OMP' statement 'G'. - - -- GIMPLE function: tree gimple_omp_parallel_clauses (gimple g) - Return the clauses associated with 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: tree * gimple_omp_parallel_clauses_ptr (gimple g) - Return a pointer to the clauses associated with 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: void gimple_omp_parallel_set_clauses (gimple g, - tree clauses) - Set 'CLAUSES' to be the list of clauses associated with - 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: tree gimple_omp_parallel_child_fn (gimple g) - Return the child function used to hold the body of 'OMP_PARALLEL' - 'G'. - - -- GIMPLE function: tree * gimple_omp_parallel_child_fn_ptr (gimple g) - Return a pointer to the child function used to hold the body of - 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: void gimple_omp_parallel_set_child_fn (gimple g, - tree child_fn) - Set 'CHILD_FN' to be the child function for 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: tree gimple_omp_parallel_data_arg (gimple g) - Return the artificial argument used to send variables and values - from the parent to the children threads in 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: tree * gimple_omp_parallel_data_arg_ptr (gimple g) - Return a pointer to the data argument for 'OMP_PARALLEL' 'G'. - - -- GIMPLE function: void gimple_omp_parallel_set_data_arg (gimple g, - tree data_arg) - Set 'DATA_ARG' to be the data argument for 'OMP_PARALLEL' 'G'. - - -File: gccint.info, Node: 'GIMPLE_OMP_RETURN', Next: 'GIMPLE_OMP_SECTION', Prev: 'GIMPLE_OMP_PARALLEL', Up: Tuple specific accessors - -11.7.19 'GIMPLE_OMP_RETURN' ---------------------------- - - -- GIMPLE function: gimple gimple_build_omp_return (bool wait_p) - Build a 'GIMPLE_OMP_RETURN' statement. 'WAIT_P' is true if this is - a non-waiting return. - - -- GIMPLE function: void gimple_omp_return_set_nowait (gimple s) - Set the nowait flag on 'GIMPLE_OMP_RETURN' statement 'S'. - - -- GIMPLE function: bool gimple_omp_return_nowait_p (gimple g) - Return true if 'OMP' return statement 'G' has the - 'GF_OMP_RETURN_NOWAIT' flag set. - - -File: gccint.info, Node: 'GIMPLE_OMP_SECTION', Next: 'GIMPLE_OMP_SECTIONS', Prev: 'GIMPLE_OMP_RETURN', Up: Tuple specific accessors - -11.7.20 'GIMPLE_OMP_SECTION' ----------------------------- - - -- GIMPLE function: gimple gimple_build_omp_section (gimple_seq body) - Build a 'GIMPLE_OMP_SECTION' statement for a sections statement. - - 'BODY' is the sequence of statements in the section. - - -- GIMPLE function: bool gimple_omp_section_last_p (gimple g) - Return true if 'OMP' section statement 'G' has the - 'GF_OMP_SECTION_LAST' flag set. - - -- GIMPLE function: void gimple_omp_section_set_last (gimple g) - Set the 'GF_OMP_SECTION_LAST' flag on 'G'. - - -File: gccint.info, Node: 'GIMPLE_OMP_SECTIONS', Next: 'GIMPLE_OMP_SINGLE', Prev: 'GIMPLE_OMP_SECTION', Up: Tuple specific accessors - -11.7.21 'GIMPLE_OMP_SECTIONS' ------------------------------ - - -- GIMPLE function: gimple gimple_build_omp_sections (gimple_seq body, - tree clauses) - Build a 'GIMPLE_OMP_SECTIONS' statement. 'BODY' is a sequence of - section statements. 'CLAUSES' are any of the 'OMP' sections - construct's clauses: private, firstprivate, lastprivate, reduction, - and nowait. - - -- GIMPLE function: gimple gimple_build_omp_sections_switch (void) - Build a 'GIMPLE_OMP_SECTIONS_SWITCH' statement. - - -- GIMPLE function: tree gimple_omp_sections_control (gimple g) - Return the control variable associated with the - 'GIMPLE_OMP_SECTIONS' in 'G'. - - -- GIMPLE function: tree * gimple_omp_sections_control_ptr (gimple g) - Return a pointer to the clauses associated with the - 'GIMPLE_OMP_SECTIONS' in 'G'. - - -- GIMPLE function: void gimple_omp_sections_set_control (gimple g, - tree control) - Set 'CONTROL' to be the set of clauses associated with the - 'GIMPLE_OMP_SECTIONS' in 'G'. - - -- GIMPLE function: tree gimple_omp_sections_clauses (gimple g) - Return the clauses associated with 'OMP_SECTIONS' 'G'. - - -- GIMPLE function: tree * gimple_omp_sections_clauses_ptr (gimple g) - Return a pointer to the clauses associated with 'OMP_SECTIONS' 'G'. - - -- GIMPLE function: void gimple_omp_sections_set_clauses (gimple g, - tree clauses) - Set 'CLAUSES' to be the set of clauses associated with - 'OMP_SECTIONS' 'G'. - - -File: gccint.info, Node: 'GIMPLE_OMP_SINGLE', Next: 'GIMPLE_PHI', Prev: 'GIMPLE_OMP_SECTIONS', Up: Tuple specific accessors - -11.7.22 'GIMPLE_OMP_SINGLE' ---------------------------- - - -- GIMPLE function: gimple gimple_build_omp_single (gimple_seq body, - tree clauses) - Build a 'GIMPLE_OMP_SINGLE' statement. 'BODY' is the sequence of - statements that will be executed once. 'CLAUSES' are any of the - 'OMP' single construct's clauses: private, firstprivate, - copyprivate, nowait. - - -- GIMPLE function: tree gimple_omp_single_clauses (gimple g) - Return the clauses associated with 'OMP_SINGLE' 'G'. - - -- GIMPLE function: tree * gimple_omp_single_clauses_ptr (gimple g) - Return a pointer to the clauses associated with 'OMP_SINGLE' 'G'. - - -- GIMPLE function: void gimple_omp_single_set_clauses (gimple g, tree - clauses) - Set 'CLAUSES' to be the clauses associated with 'OMP_SINGLE' 'G'. - - -File: gccint.info, Node: 'GIMPLE_PHI', Next: 'GIMPLE_RESX', Prev: 'GIMPLE_OMP_SINGLE', Up: Tuple specific accessors - -11.7.23 'GIMPLE_PHI' --------------------- - - -- GIMPLE function: unsigned gimple_phi_capacity (gimple g) - Return the maximum number of arguments supported by 'GIMPLE_PHI' - 'G'. - - -- GIMPLE function: unsigned gimple_phi_num_args (gimple g) - Return the number of arguments in 'GIMPLE_PHI' 'G'. This must - always be exactly the number of incoming edges for the basic block - holding 'G'. - - -- GIMPLE function: tree gimple_phi_result (gimple g) - Return the 'SSA' name created by 'GIMPLE_PHI' 'G'. - - -- GIMPLE function: tree * gimple_phi_result_ptr (gimple g) - Return a pointer to the 'SSA' name created by 'GIMPLE_PHI' 'G'. - - -- GIMPLE function: void gimple_phi_set_result (gimple g, tree result) - Set 'RESULT' to be the 'SSA' name created by 'GIMPLE_PHI' 'G'. - - -- GIMPLE function: struct phi_arg_d * gimple_phi_arg (gimple g, index) - Return the 'PHI' argument corresponding to incoming edge 'INDEX' - for 'GIMPLE_PHI' 'G'. - - -- GIMPLE function: void gimple_phi_set_arg (gimple g, index, struct - phi_arg_d * phiarg) - Set 'PHIARG' to be the argument corresponding to incoming edge - 'INDEX' for 'GIMPLE_PHI' 'G'. - - -File: gccint.info, Node: 'GIMPLE_RESX', Next: 'GIMPLE_RETURN', Prev: 'GIMPLE_PHI', Up: Tuple specific accessors - -11.7.24 'GIMPLE_RESX' ---------------------- - - -- GIMPLE function: gimple gimple_build_resx (int region) - Build a 'GIMPLE_RESX' statement which is a statement. This - statement is a placeholder for _Unwind_Resume before we know if a - function call or a branch is needed. 'REGION' is the exception - region from which control is flowing. - - -- GIMPLE function: int gimple_resx_region (gimple g) - Return the region number for 'GIMPLE_RESX' 'G'. - - -- GIMPLE function: void gimple_resx_set_region (gimple g, int region) - Set 'REGION' to be the region number for 'GIMPLE_RESX' 'G'. - - -File: gccint.info, Node: 'GIMPLE_RETURN', Next: 'GIMPLE_SWITCH', Prev: 'GIMPLE_RESX', Up: Tuple specific accessors - -11.7.25 'GIMPLE_RETURN' ------------------------ - - -- GIMPLE function: gimple gimple_build_return (tree retval) - Build a 'GIMPLE_RETURN' statement whose return value is retval. - - -- GIMPLE function: tree gimple_return_retval (gimple g) - Return the return value for 'GIMPLE_RETURN' 'G'. - - -- GIMPLE function: void gimple_return_set_retval (gimple g, tree - retval) - Set 'RETVAL' to be the return value for 'GIMPLE_RETURN' 'G'. - - -File: gccint.info, Node: 'GIMPLE_SWITCH', Next: 'GIMPLE_TRY', Prev: 'GIMPLE_RETURN', Up: Tuple specific accessors - -11.7.26 'GIMPLE_SWITCH' ------------------------ - - -- GIMPLE function: gimple gimple_build_switch (tree index, tree - default_label, 'VEC'(tree,heap) *args) - Build a 'GIMPLE_SWITCH' statement. 'INDEX' is the index variable - to switch on, and 'DEFAULT_LABEL' represents the default label. - 'ARGS' is a vector of 'CASE_LABEL_EXPR' trees that contain the - non-default case labels. Each label is a tree of code - 'CASE_LABEL_EXPR'. - - -- GIMPLE function: unsigned gimple_switch_num_labels (gimple g) - Return the number of labels associated with the switch statement - 'G'. - - -- GIMPLE function: void gimple_switch_set_num_labels (gimple g, - unsigned nlabels) - Set 'NLABELS' to be the number of labels for the switch statement - 'G'. - - -- GIMPLE function: tree gimple_switch_index (gimple g) - Return the index variable used by the switch statement 'G'. - - -- GIMPLE function: void gimple_switch_set_index (gimple g, tree index) - Set 'INDEX' to be the index variable for switch statement 'G'. - - -- GIMPLE function: tree gimple_switch_label (gimple g, unsigned index) - Return the label numbered 'INDEX'. The default label is 0, - followed by any labels in a switch statement. - - -- GIMPLE function: void gimple_switch_set_label (gimple g, unsigned - index, tree label) - Set the label number 'INDEX' to 'LABEL'. 0 is always the default - label. - - -- GIMPLE function: tree gimple_switch_default_label (gimple g) - Return the default label for a switch statement. - - -- GIMPLE function: void gimple_switch_set_default_label (gimple g, - tree label) - Set the default label for a switch statement. - - -File: gccint.info, Node: 'GIMPLE_TRY', Next: 'GIMPLE_WITH_CLEANUP_EXPR', Prev: 'GIMPLE_SWITCH', Up: Tuple specific accessors - -11.7.27 'GIMPLE_TRY' --------------------- - - -- GIMPLE function: gimple gimple_build_try (gimple_seq eval, - gimple_seq cleanup, unsigned int kind) - Build a 'GIMPLE_TRY' statement. 'EVAL' is a sequence with the - expression to evaluate. 'CLEANUP' is a sequence of statements to - run at clean-up time. 'KIND' is the enumeration value - 'GIMPLE_TRY_CATCH' if this statement denotes a try/catch construct - or 'GIMPLE_TRY_FINALLY' if this statement denotes a try/finally - construct. - - -- GIMPLE function: enum gimple_try_flags gimple_try_kind (gimple g) - Return the kind of try block represented by 'GIMPLE_TRY' 'G'. This - is either 'GIMPLE_TRY_CATCH' or 'GIMPLE_TRY_FINALLY'. - - -- GIMPLE function: bool gimple_try_catch_is_cleanup (gimple g) - Return the 'GIMPLE_TRY_CATCH_IS_CLEANUP' flag. - - -- GIMPLE function: gimple_seq gimple_try_eval (gimple g) - Return the sequence of statements used as the body for 'GIMPLE_TRY' - 'G'. - - -- GIMPLE function: gimple_seq gimple_try_cleanup (gimple g) - Return the sequence of statements used as the cleanup body for - 'GIMPLE_TRY' 'G'. - - -- GIMPLE function: void gimple_try_set_catch_is_cleanup (gimple g, - bool catch_is_cleanup) - Set the 'GIMPLE_TRY_CATCH_IS_CLEANUP' flag. - - -- GIMPLE function: void gimple_try_set_eval (gimple g, gimple_seq - eval) - Set 'EVAL' to be the sequence of statements to use as the body for - 'GIMPLE_TRY' 'G'. - - -- GIMPLE function: void gimple_try_set_cleanup (gimple g, gimple_seq - cleanup) - Set 'CLEANUP' to be the sequence of statements to use as the - cleanup body for 'GIMPLE_TRY' 'G'. - - -File: gccint.info, Node: 'GIMPLE_WITH_CLEANUP_EXPR', Prev: 'GIMPLE_TRY', Up: Tuple specific accessors - -11.7.28 'GIMPLE_WITH_CLEANUP_EXPR' ----------------------------------- - - -- GIMPLE function: gimple gimple_build_wce (gimple_seq cleanup) - Build a 'GIMPLE_WITH_CLEANUP_EXPR' statement. 'CLEANUP' is the - clean-up expression. - - -- GIMPLE function: gimple_seq gimple_wce_cleanup (gimple g) - Return the cleanup sequence for cleanup statement 'G'. - - -- GIMPLE function: void gimple_wce_set_cleanup (gimple g, gimple_seq - cleanup) - Set 'CLEANUP' to be the cleanup sequence for 'G'. - - -- GIMPLE function: bool gimple_wce_cleanup_eh_only (gimple g) - Return the 'CLEANUP_EH_ONLY' flag for a 'WCE' tuple. - - -- GIMPLE function: void gimple_wce_set_cleanup_eh_only (gimple g, bool - eh_only_p) - Set the 'CLEANUP_EH_ONLY' flag for a 'WCE' tuple. - - -File: gccint.info, Node: GIMPLE sequences, Next: Sequence iterators, Prev: Tuple specific accessors, Up: GIMPLE - -11.8 GIMPLE sequences -===================== - -GIMPLE sequences are the tuple equivalent of 'STATEMENT_LIST''s used in -'GENERIC'. They are used to chain statements together, and when used in -conjunction with sequence iterators, provide a framework for iterating -through statements. - - GIMPLE sequences are of type struct 'gimple_sequence', but are more -commonly passed by reference to functions dealing with sequences. The -type for a sequence pointer is 'gimple_seq' which is the same as struct -'gimple_sequence' *. When declaring a local sequence, you can define a -local variable of type struct 'gimple_sequence'. When declaring a -sequence allocated on the garbage collected heap, use the function -'gimple_seq_alloc' documented below. - - There are convenience functions for iterating through sequences in the -section entitled Sequence Iterators. - - Below is a list of functions to manipulate and query sequences. - - -- GIMPLE function: void gimple_seq_add_stmt (gimple_seq *seq, gimple - g) - Link a gimple statement to the end of the sequence *'SEQ' if 'G' is - not 'NULL'. If *'SEQ' is 'NULL', allocate a sequence before - linking. - - -- GIMPLE function: void gimple_seq_add_seq (gimple_seq *dest, - gimple_seq src) - Append sequence 'SRC' to the end of sequence *'DEST' if 'SRC' is - not 'NULL'. If *'DEST' is 'NULL', allocate a new sequence before - appending. - - -- GIMPLE function: gimple_seq gimple_seq_deep_copy (gimple_seq src) - Perform a deep copy of sequence 'SRC' and return the result. - - -- GIMPLE function: gimple_seq gimple_seq_reverse (gimple_seq seq) - Reverse the order of the statements in the sequence 'SEQ'. Return - 'SEQ'. - - -- GIMPLE function: gimple gimple_seq_first (gimple_seq s) - Return the first statement in sequence 'S'. - - -- GIMPLE function: gimple gimple_seq_last (gimple_seq s) - Return the last statement in sequence 'S'. - - -- GIMPLE function: void gimple_seq_set_last (gimple_seq s, gimple - last) - Set the last statement in sequence 'S' to the statement in 'LAST'. - - -- GIMPLE function: void gimple_seq_set_first (gimple_seq s, gimple - first) - Set the first statement in sequence 'S' to the statement in - 'FIRST'. - - -- GIMPLE function: void gimple_seq_init (gimple_seq s) - Initialize sequence 'S' to an empty sequence. - - -- GIMPLE function: gimple_seq gimple_seq_alloc (void) - Allocate a new sequence in the garbage collected store and return - it. - - -- GIMPLE function: void gimple_seq_copy (gimple_seq dest, gimple_seq - src) - Copy the sequence 'SRC' into the sequence 'DEST'. - - -- GIMPLE function: bool gimple_seq_empty_p (gimple_seq s) - Return true if the sequence 'S' is empty. - - -- GIMPLE function: gimple_seq bb_seq (basic_block bb) - Returns the sequence of statements in 'BB'. - - -- GIMPLE function: void set_bb_seq (basic_block bb, gimple_seq seq) - Sets the sequence of statements in 'BB' to 'SEQ'. - - -- GIMPLE function: bool gimple_seq_singleton_p (gimple_seq seq) - Determine whether 'SEQ' contains exactly one statement. - - -File: gccint.info, Node: Sequence iterators, Next: Adding a new GIMPLE statement code, Prev: GIMPLE sequences, Up: GIMPLE - -11.9 Sequence iterators -======================= - -Sequence iterators are convenience constructs for iterating through -statements in a sequence. Given a sequence 'SEQ', here is a typical use -of gimple sequence iterators: - - gimple_stmt_iterator gsi; - - for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi)) - { - gimple g = gsi_stmt (gsi); - /* Do something with gimple statement G. */ - } - - Backward iterations are possible: - - for (gsi = gsi_last (seq); !gsi_end_p (gsi); gsi_prev (&gsi)) - - Forward and backward iterations on basic blocks are possible with -'gsi_start_bb' and 'gsi_last_bb'. - - In the documentation below we sometimes refer to enum -'gsi_iterator_update'. The valid options for this enumeration are: - - * 'GSI_NEW_STMT' Only valid when a single statement is added. Move - the iterator to it. - - * 'GSI_SAME_STMT' Leave the iterator at the same statement. - - * 'GSI_CONTINUE_LINKING' Move iterator to whatever position is - suitable for linking other statements in the same direction. - - Below is a list of the functions used to manipulate and use statement -iterators. - - -- GIMPLE function: gimple_stmt_iterator gsi_start (gimple_seq seq) - Return a new iterator pointing to the sequence 'SEQ''s first - statement. If 'SEQ' is empty, the iterator's basic block is - 'NULL'. Use 'gsi_start_bb' instead when the iterator needs to - always have the correct basic block set. - - -- GIMPLE function: gimple_stmt_iterator gsi_start_bb (basic_block bb) - Return a new iterator pointing to the first statement in basic - block 'BB'. - - -- GIMPLE function: gimple_stmt_iterator gsi_last (gimple_seq seq) - Return a new iterator initially pointing to the last statement of - sequence 'SEQ'. If 'SEQ' is empty, the iterator's basic block is - 'NULL'. Use 'gsi_last_bb' instead when the iterator needs to - always have the correct basic block set. - - -- GIMPLE function: gimple_stmt_iterator gsi_last_bb (basic_block bb) - Return a new iterator pointing to the last statement in basic block - 'BB'. - - -- GIMPLE function: bool gsi_end_p (gimple_stmt_iterator i) - Return 'TRUE' if at the end of 'I'. - - -- GIMPLE function: bool gsi_one_before_end_p (gimple_stmt_iterator i) - Return 'TRUE' if we're one statement before the end of 'I'. - - -- GIMPLE function: void gsi_next (gimple_stmt_iterator *i) - Advance the iterator to the next gimple statement. - - -- GIMPLE function: void gsi_prev (gimple_stmt_iterator *i) - Advance the iterator to the previous gimple statement. - - -- GIMPLE function: gimple gsi_stmt (gimple_stmt_iterator i) - Return the current stmt. - - -- GIMPLE function: gimple_stmt_iterator gsi_after_labels (basic_block - bb) - Return a block statement iterator that points to the first - non-label statement in block 'BB'. - - -- GIMPLE function: gimple * gsi_stmt_ptr (gimple_stmt_iterator *i) - Return a pointer to the current stmt. - - -- GIMPLE function: basic_block gsi_bb (gimple_stmt_iterator i) - Return the basic block associated with this iterator. - - -- GIMPLE function: gimple_seq gsi_seq (gimple_stmt_iterator i) - Return the sequence associated with this iterator. - - -- GIMPLE function: void gsi_remove (gimple_stmt_iterator *i, bool - remove_eh_info) - Remove the current stmt from the sequence. The iterator is updated - to point to the next statement. When 'REMOVE_EH_INFO' is true we - remove the statement pointed to by iterator 'I' from the 'EH' - tables. Otherwise we do not modify the 'EH' tables. Generally, - 'REMOVE_EH_INFO' should be true when the statement is going to be - removed from the 'IL' and not reinserted elsewhere. - - -- GIMPLE function: void gsi_link_seq_before (gimple_stmt_iterator *i, - gimple_seq seq, enum gsi_iterator_update mode) - Links the sequence of statements 'SEQ' before the statement pointed - by iterator 'I'. 'MODE' indicates what to do with the iterator - after insertion (see 'enum gsi_iterator_update' above). - - -- GIMPLE function: void gsi_link_before (gimple_stmt_iterator *i, - gimple g, enum gsi_iterator_update mode) - Links statement 'G' before the statement pointed-to by iterator - 'I'. Updates iterator 'I' according to 'MODE'. - - -- GIMPLE function: void gsi_link_seq_after (gimple_stmt_iterator *i, - gimple_seq seq, enum gsi_iterator_update mode) - Links sequence 'SEQ' after the statement pointed-to by iterator - 'I'. 'MODE' is as in 'gsi_insert_after'. - - -- GIMPLE function: void gsi_link_after (gimple_stmt_iterator *i, - gimple g, enum gsi_iterator_update mode) - Links statement 'G' after the statement pointed-to by iterator 'I'. - 'MODE' is as in 'gsi_insert_after'. - - -- GIMPLE function: gimple_seq gsi_split_seq_after - (gimple_stmt_iterator i) - Move all statements in the sequence after 'I' to a new sequence. - Return this new sequence. - - -- GIMPLE function: gimple_seq gsi_split_seq_before - (gimple_stmt_iterator *i) - Move all statements in the sequence before 'I' to a new sequence. - Return this new sequence. - - -- GIMPLE function: void gsi_replace (gimple_stmt_iterator *i, gimple - stmt, bool update_eh_info) - Replace the statement pointed-to by 'I' to 'STMT'. If - 'UPDATE_EH_INFO' is true, the exception handling information of the - original statement is moved to the new statement. - - -- GIMPLE function: void gsi_insert_before (gimple_stmt_iterator *i, - gimple stmt, enum gsi_iterator_update mode) - Insert statement 'STMT' before the statement pointed-to by iterator - 'I', update 'STMT''s basic block and scan it for new operands. - 'MODE' specifies how to update iterator 'I' after insertion (see - enum 'gsi_iterator_update'). - - -- GIMPLE function: void gsi_insert_seq_before (gimple_stmt_iterator - *i, gimple_seq seq, enum gsi_iterator_update mode) - Like 'gsi_insert_before', but for all the statements in 'SEQ'. - - -- GIMPLE function: void gsi_insert_after (gimple_stmt_iterator *i, - gimple stmt, enum gsi_iterator_update mode) - Insert statement 'STMT' after the statement pointed-to by iterator - 'I', update 'STMT''s basic block and scan it for new operands. - 'MODE' specifies how to update iterator 'I' after insertion (see - enum 'gsi_iterator_update'). - - -- GIMPLE function: void gsi_insert_seq_after (gimple_stmt_iterator *i, - gimple_seq seq, enum gsi_iterator_update mode) - Like 'gsi_insert_after', but for all the statements in 'SEQ'. - - -- GIMPLE function: gimple_stmt_iterator gsi_for_stmt (gimple stmt) - Finds iterator for 'STMT'. - - -- GIMPLE function: void gsi_move_after (gimple_stmt_iterator *from, - gimple_stmt_iterator *to) - Move the statement at 'FROM' so it comes right after the statement - at 'TO'. - - -- GIMPLE function: void gsi_move_before (gimple_stmt_iterator *from, - gimple_stmt_iterator *to) - Move the statement at 'FROM' so it comes right before the statement - at 'TO'. - - -- GIMPLE function: void gsi_move_to_bb_end (gimple_stmt_iterator - *from, basic_block bb) - Move the statement at 'FROM' to the end of basic block 'BB'. - - -- GIMPLE function: void gsi_insert_on_edge (edge e, gimple stmt) - Add 'STMT' to the pending list of edge 'E'. No actual insertion is - made until a call to 'gsi_commit_edge_inserts'() is made. - - -- GIMPLE function: void gsi_insert_seq_on_edge (edge e, gimple_seq - seq) - Add the sequence of statements in 'SEQ' to the pending list of edge - 'E'. No actual insertion is made until a call to - 'gsi_commit_edge_inserts'() is made. - - -- GIMPLE function: basic_block gsi_insert_on_edge_immediate (edge e, - gimple stmt) - Similar to 'gsi_insert_on_edge'+'gsi_commit_edge_inserts'. If a - new block has to be created, it is returned. - - -- GIMPLE function: void gsi_commit_one_edge_insert (edge e, - basic_block *new_bb) - Commit insertions pending at edge 'E'. If a new block is created, - set 'NEW_BB' to this block, otherwise set it to 'NULL'. - - -- GIMPLE function: void gsi_commit_edge_inserts (void) - This routine will commit all pending edge insertions, creating any - new basic blocks which are necessary. - - -File: gccint.info, Node: Adding a new GIMPLE statement code, Next: Statement and operand traversals, Prev: Sequence iterators, Up: GIMPLE - -11.10 Adding a new GIMPLE statement code -======================================== - -The first step in adding a new GIMPLE statement code, is modifying the -file 'gimple.def', which contains all the GIMPLE codes. Then you must -add a corresponding structure, and an entry in 'union -gimple_statement_d', both of which are located in 'gimple.h'. This in -turn, will require you to add a corresponding 'GTY' tag in -'gsstruct.def', and code to handle this tag in 'gss_for_code' which is -located in 'gimple.c'. - - In order for the garbage collector to know the size of the structure -you created in 'gimple.h', you need to add a case to handle your new -GIMPLE statement in 'gimple_size' which is located in 'gimple.c'. - - You will probably want to create a function to build the new gimple -statement in 'gimple.c'. The function should be called -'gimple_build_NEW-TUPLE-NAME', and should return the new tuple of type -gimple. - - If your new statement requires accessors for any members or operands it -may have, put simple inline accessors in 'gimple.h' and any non-trivial -accessors in 'gimple.c' with a corresponding prototype in 'gimple.h'. - - -File: gccint.info, Node: Statement and operand traversals, Prev: Adding a new GIMPLE statement code, Up: GIMPLE - -11.11 Statement and operand traversals -====================================== - -There are two functions available for walking statements and sequences: -'walk_gimple_stmt' and 'walk_gimple_seq', accordingly, and a third -function for walking the operands in a statement: 'walk_gimple_op'. - - -- GIMPLE function: tree walk_gimple_stmt (gimple_stmt_iterator *gsi, - walk_stmt_fn callback_stmt, walk_tree_fn callback_op, struct - walk_stmt_info *wi) - This function is used to walk the current statement in 'GSI', - optionally using traversal state stored in 'WI'. If 'WI' is - 'NULL', no state is kept during the traversal. - - The callback 'CALLBACK_STMT' is called. If 'CALLBACK_STMT' returns - true, it means that the callback function has handled all the - operands of the statement and it is not necessary to walk its - operands. - - If 'CALLBACK_STMT' is 'NULL' or it returns false, 'CALLBACK_OP' is - called on each operand of the statement via 'walk_gimple_op'. If - 'walk_gimple_op' returns non-'NULL' for any operand, the remaining - operands are not scanned. - - The return value is that returned by the last call to - 'walk_gimple_op', or 'NULL_TREE' if no 'CALLBACK_OP' is specified. - - -- GIMPLE function: tree walk_gimple_op (gimple stmt, walk_tree_fn - callback_op, struct walk_stmt_info *wi) - Use this function to walk the operands of statement 'STMT'. Every - operand is walked via 'walk_tree' with optional state information - in 'WI'. - - 'CALLBACK_OP' is called on each operand of 'STMT' via 'walk_tree'. - Additional parameters to 'walk_tree' must be stored in 'WI'. For - each operand 'OP', 'walk_tree' is called as: - - walk_tree (&OP, CALLBACK_OP, WI, PSET) - - If 'CALLBACK_OP' returns non-'NULL' for an operand, the remaining - operands are not scanned. The return value is that returned by the - last call to 'walk_tree', or 'NULL_TREE' if no 'CALLBACK_OP' is - specified. - - -- GIMPLE function: tree walk_gimple_seq (gimple_seq seq, walk_stmt_fn - callback_stmt, walk_tree_fn callback_op, struct walk_stmt_info - *wi) - This function walks all the statements in the sequence 'SEQ' - calling 'walk_gimple_stmt' on each one. 'WI' is as in - 'walk_gimple_stmt'. If 'walk_gimple_stmt' returns non-'NULL', the - walk is stopped and the value returned. Otherwise, all the - statements are walked and 'NULL_TREE' returned. - - -File: gccint.info, Node: Tree SSA, Next: RTL, Prev: GIMPLE, Up: Top - -12 Analysis and Optimization of GIMPLE tuples -********************************************* - -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: - -* Annotations:: Attributes for variables. -* SSA Operands:: SSA names referenced by GIMPLE statements. -* SSA:: Static Single Assignment representation. -* Alias analysis:: Representing aliased loads and stores. -* Memory model:: Memory model used by the middle-end. - - -File: gccint.info, Node: Annotations, Next: SSA Operands, Up: Tree SSA - -12.1 Annotations -================ - -The optimizers need to associate attributes with variables during the -optimization process. For instance, we need to know whether a variable -has aliases. All these attributes are stored in data structures called -annotations which are then linked to the field 'ann' in 'struct -tree_common'. - - -File: gccint.info, Node: SSA Operands, Next: SSA, Prev: Annotations, Up: Tree SSA - -12.2 SSA Operands -================= - -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 -'VAR_DECL', 'PARM_DECL' or '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 'SSA_VAR_P' returns nonzero -is considered when scanning statement operands. However, not all -'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: "real" and -"virtual". An operand for which '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 - - { - int a, b; - a = b - } - - Since 'a' and 'b' are non-aliased locals, the statement 'a = b' will -have one real definition and one real use because variable 'a' is -completely modified with the contents of variable 'b'. Real definition -are also known as "killing definitions". Similarly, the use of 'b' -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 "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 "may definition". For instance, -given - - { - int a, b, *p; - - if (...) - p = &a; - else - p = &b; - *p = 5; - return *p; - } - - The assignment '*p = 5' may be a definition of 'a' or 'b'. If we -cannot determine statically where '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 'a' and '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 '-vops' option to '-fdump-tree': - - { - int a, b, *p; - - if (...) - p = &a; - else - p = &b; - # a = VDEF <a> - # b = VDEF <b> - *p = 5; - - # VUSE <a> - # VUSE <b> - return *p; - } - - Notice that 'VDEF' 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 "may definition" or "aliased store". -The presence of the second copy of the variable in the 'VDEF' 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 -'update_stmt'. If statement elements are changed via 'SET_USE' or -'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 'update_stmt' -when complete. Calling one of the 'bsi_insert' routines or -'bsi_replace' performs an implicit call to 'update_stmt'. - -12.2.1 Operand Iterators And Access Routines --------------------------------------------- - -Operands are collected by '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: - - 1. '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 'tree', 'def_operand_p', or 'use_operand_p'. - - 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); - - 2. 'ZERO_SSA_OPERANDS': This macro returns true if there are no - operands matching the specified flags. - - if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) - return; - - 3. '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. - - int count = NUM_SSA_OPERANDS (stmt, flags) - - If you wish to iterate over some or all operands, use the -'FOR_EACH_SSA_{USE,DEF,TREE}_OPERAND' iterator. For example, to print -all the operands for a statement: - - 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); - } - - How to choose the appropriate iterator: - - 1. Determine whether you are need to see the operand pointers, or just - the trees, and choose the appropriate macro: - - Need Macro: - ---- ------- - use_operand_p FOR_EACH_SSA_USE_OPERAND - def_operand_p FOR_EACH_SSA_DEF_OPERAND - tree FOR_EACH_SSA_TREE_OPERAND - - 2. 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. - - 3. Determine which operands you wish to use, and specify the flags of - those you are interested in. They are documented in - 'tree-ssa-operands.h': - - #define SSA_OP_USE 0x01 /* Real USE operands. */ - #define SSA_OP_DEF 0x02 /* Real DEF operands. */ - #define SSA_OP_VUSE 0x04 /* VUSE operands. */ - #define SSA_OP_VDEF 0x08 /* VDEF operands. */ - - /* These are commonly grouped operand flags. */ - #define SSA_OP_VIRTUAL_USES (SSA_OP_VUSE) - #define SSA_OP_VIRTUAL_DEFS (SSA_OP_VDEF) - #define SSA_OP_ALL_VIRTUALS (SSA_OP_VIRTUAL_USES | SSA_OP_VIRTUAL_DEFS) - #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) - - So if you want to look at the use pointers for all the 'USE' and 'VUSE' -operands, you would do something like: - - 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); - } - - The 'TREE' macro is basically the same as the 'USE' and 'DEF' macros, -only with the use or def dereferenced via 'USE_FROM_PTR (use_p)' and -'DEF_FROM_PTR (def_p)'. Since we aren't using operand pointers, use and -defs flags can be mixed. - - tree var; - ssa_op_iter iter; - - FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_VUSE) - { - print_generic_expr (stderr, var, TDF_SLIM); - } - - 'VDEF's are broken into two flags, one for the 'DEF' portion -('SSA_OP_VDEF') and one for the USE portion ('SSA_OP_VUSE'). - - There are many examples in the code, in addition to the documentation -in 'tree-ssa-operands.h' and 'ssa-iterators.h'. - - There are also a couple of variants on the stmt iterators regarding PHI -nodes. - - 'FOR_EACH_PHI_ARG' Works exactly like 'FOR_EACH_SSA_USE_OPERAND', -except it works over 'PHI' arguments instead of statement operands. - - /* 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 PHI use. */ - FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_ALL_USES) - my_code; - - 'FOR_EACH_PHI_OR_STMT_{USE,DEF}' works exactly like -'FOR_EACH_SSA_{USE,DEF}_OPERAND', except it will function on either a -statement or a 'PHI' node. These should be used when it is appropriate -but they are not quite as efficient as the individual 'FOR_EACH_PHI' and -'FOR_EACH_SSA' routines. - - 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; - } - -12.2.2 Immediate Uses ---------------------- - -Immediate use information is now always available. Using the immediate -use iterators, you may examine every use of any 'SSA_NAME'. For -instance, to change each use of 'ssa_var' to 'ssa_var2' and call -fold_stmt on each stmt after that is done: - - 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); - } - - There are 2 iterators which can be used. '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 'FOR_EACH_IMM_USE_STMT' and -'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 'BREAK_FROM_IMM_USE_SAFE' is provided to -do this : - - 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); - } - - There are checks in '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 'FOR_EACH_IMM_USE_FAST' traverse. - - Some useful functions and macros: - 1. 'has_zero_uses (ssa_var)' : Returns true if there are no uses of - 'ssa_var'. - 2. 'has_single_use (ssa_var)' : Returns true if there is only a single - use of 'ssa_var'. - 3. 'single_imm_use (ssa_var, use_operand_p *ptr, tree *stmt)' : - Returns true if there is only a single use of 'ssa_var', and also - returns the use pointer and statement it occurs in, in the second - and third parameters. - 4. 'num_imm_uses (ssa_var)' : Returns the number of immediate uses of - 'ssa_var'. It is better not to use this if possible since it - simply utilizes a loop to count the uses. - 5. 'PHI_ARG_INDEX_FROM_USE (use_p)' : Given a use within a 'PHI' node, - return the index number for the use. An assert is triggered if the - use isn't located in a 'PHI' node. - 6. 'USE_STMT (use_p)' : Return the statement a use occurs in. - - Note that uses are not put into an immediate use list until their -statement is actually inserted into the instruction stream via a '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 'mark_stmt_modified' -instead of 'update_stmt'. When lazy updating is no longer required, all -the modified statements must have 'update_stmt' called in order to bring -them up to date. This must be done before the optimization is finished, -or 'verify_ssa' will trigger an abort. - - This is done with a simple loop over the instruction stream: - 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)); - } - - -File: gccint.info, Node: SSA, Next: Alias analysis, Prev: SSA Operands, Up: Tree SSA - -12.3 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 '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 'SSA_NAME' nodes. The renaming -process in 'tree-ssa.c' wraps every real and virtual operand with an -'SSA_NAME' node which contains the version number and the statement that -created the 'SSA_NAME'. Only definitions and virtual definitions may -create new 'SSA_NAME' nodes. - - Sometimes, flow of control makes it impossible to determine the most -recent version of a variable. In these cases, the compiler inserts an -artificial definition for that variable called "PHI function" or "PHI -node". This new definition merges all the incoming versions of the -variable to create a new name for it. For instance, - - 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; - - Since it is not possible to determine which of the three branches will -be taken at runtime, we don't know which of 'a_1', 'a_2' or 'a_3' to use -at the return statement. So, the SSA renamer creates a new version -'a_4' which is assigned the result of "merging" 'a_1', 'a_2' and 'a_3'. -Hence, PHI nodes mean "one of these operands. I don't know which". - - The following functions can be used to examine PHI nodes - - -- Function: gimple_phi_result (PHI) - Returns the 'SSA_NAME' created by PHI node PHI (i.e., PHI's LHS). - - -- Function: gimple_phi_num_args (PHI) - Returns the number of arguments in PHI. This number is exactly the - number of incoming edges to the basic block holding PHI. - - -- Function: gimple_phi_arg (PHI, I) - Returns Ith argument of PHI. - - -- Function: gimple_phi_arg_edge (PHI, I) - Returns the incoming edge for the Ith argument of PHI. - - -- Function: gimple_phi_arg_def (PHI, I) - Returns the 'SSA_NAME' for the Ith argument of PHI. - -12.3.1 Preserving the 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: - - 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 - - Suppose that we insert new names 'x_10' and 'x_11' (lines '4' and '8'). - - 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 - - We want to replace all the uses of 'x_1' with the new definitions of -'x_10' and 'x_11'. Note that the only uses that should be replaced are -those at lines '5', '9' and '11'. Also, the use of 'x_7' at line '9' -should _not_ be replaced (this is why we cannot just mark symbol 'x' for -renaming). - - Additionally, we may need to insert a PHI node at line '11' because -that is a merge point for 'x_10' and 'x_11'. So the use of 'x_1' at -line '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 'register_new_name_mapping' -(note that if your pass creates new code by duplicating basic blocks, -the call to 'tree_duplicate_bb' will set up the necessary mappings -automatically). - - After the replacement mappings have been registered and new symbols -marked for renaming, a call to 'update_ssa' makes the registered -changes. This can be done with an explicit call or by creating 'TODO' -flags in the 'tree_opt_pass' structure for your pass. There are several -'TODO' flags that control the behavior of 'update_ssa': - - * '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 'O_j' in - blocks reached by all the new and old definitions for 'O_j'. If - the iterated dominance frontier for '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 'O_j'. This would lead to uninitialized - warnings for 'O_j''s symbol. - - * '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). - - * '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 'O_j' even if it means that some - arguments will come from the default definition of 'O_j''s symbol - (e.g., '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. - - * '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. - -12.3.2 Preserving the 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, statement -modifications should be bracketed between calls to 'push_stmt_changes' -and 'pop_stmt_changes'. For example, - - munge_stmt (tree stmt) - { - push_stmt_changes (&stmt); - ... rewrite STMT ... - pop_stmt_changes (&stmt); - } - - The call to 'push_stmt_changes' saves the current state of the -statement operands and the call to 'pop_stmt_changes' compares the saved -state with the current one and does the appropriate symbol marking for -the SSA renamer. - - It is possible to modify several statements at a time, provided that -'push_stmt_changes' and 'pop_stmt_changes' are called in LIFO order, as -when processing a stack of statements. - - Additionally, if the pass discovers that it did not need to make -changes to the statement after calling 'push_stmt_changes', it can -simply discard the topmost change buffer by calling -'discard_stmt_changes'. This will avoid the expensive operand re-scan -operation and the buffer comparison that determines if symbols need to -be marked for renaming. - -12.3.3 Examining 'SSA_NAME' nodes ---------------------------------- - -The following macros can be used to examine 'SSA_NAME' nodes - - -- Macro: SSA_NAME_DEF_STMT (VAR) - Returns the statement S that creates the 'SSA_NAME' VAR. If S is - an empty statement (i.e., 'IS_EMPTY_STMT (S)' returns 'true'), it - means that the first reference to this variable is a USE or a VUSE. - - -- Macro: SSA_NAME_VERSION (VAR) - Returns the version number of the 'SSA_NAME' object VAR. - -12.3.4 Walking the dominator tree ---------------------------------- - - -- Tree SSA function: void walk_dominator_tree (WALK_DATA, BB) - - This function walks the dominator tree for the current CFG calling - a set of callback functions defined in STRUCT DOM_WALK_DATA in - 'domwalk.h'. The call back functions you need to define give you - hooks to execute custom code at various points during traversal: - - 1. Once to initialize any local data needed while processing 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. - - 2. Once before traversing all the statements in the BB. - - 3. Once for every statement inside BB. - - 4. Once after traversing all the statements and before recursing - into BB's dominator children. - - 5. It then recurses into all the dominator children of BB. - - 6. After recursing into all the dominator children of BB it can, - optionally, traverse every statement in BB again (i.e., - repeating steps 2 and 3). - - 7. Once after walking the statements in BB and BB's dominator - children. At this stage, the block local data stack is - popped. - - -File: gccint.info, Node: Alias analysis, Next: Memory model, Prev: SSA, Up: Tree SSA - -12.4 Alias analysis -=================== - -Alias analysis in GIMPLE SSA form consists of two pieces. First the -virtual SSA web ties conflicting memory accesses and provides a SSA -use-def chain and SSA immediate-use chains for walking possibly -dependent memory accesses. Second an alias-oracle can be queried to -disambiguate explicit and implicit memory references. - - 1. Memory SSA form. - - All statements that may use memory have exactly one accompanied use - of a virtual SSA name that represents the state of memory at the - given point in the IL. - - All statements that may define memory have exactly one accompanied - definition of a virtual SSA name using the previous state of memory - and defining the new state of memory after the given point in the - IL. - - int i; - int foo (void) - { - # .MEM_3 = VDEF <.MEM_2(D)> - i = 1; - # VUSE <.MEM_3> - return i; - } - - The virtual SSA names in this case are '.MEM_2(D)' and '.MEM_3'. - The store to the global variable 'i' defines '.MEM_3' invalidating - '.MEM_2(D)'. The load from 'i' uses that new state '.MEM_3'. - - The virtual SSA web serves as constraints to SSA optimizers - preventing illegitimate code-motion and optimization. It also - provides a way to walk related memory statements. - - 2. Points-to and escape analysis. - - Points-to analysis builds a set of constraints from the GIMPLE SSA - IL representing all pointer operations and facts we do or do not - know about pointers. Solving this set of constraints yields a - conservatively correct solution for each pointer variable in the - program (though we are only interested in SSA name pointers) as to - what it may possibly point to. - - This points-to solution for a given SSA name pointer is stored in - the 'pt_solution' sub-structure of the 'SSA_NAME_PTR_INFO' record. - The following accessor functions are available: - - * 'pt_solution_includes' - * 'pt_solutions_intersect' - - Points-to analysis also computes the solution for two special set - of pointers, 'ESCAPED' and 'CALLUSED'. Those represent all memory - that has escaped the scope of analysis or that is used by pure or - nested const calls. - - 3. Type-based alias analysis - - Type-based alias analysis is frontend dependent though generic - support is provided by the middle-end in 'alias.c'. TBAA code is - used by both tree optimizers and RTL optimizers. - - Every language that wishes to perform language-specific alias - analysis should define a function that computes, given a '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 - 'c_get_alias_set'. - - 4. Tree alias-oracle - - The tree alias-oracle provides means to disambiguate two memory - references and memory references against statements. The following - queries are available: - - * 'refs_may_alias_p' - * 'ref_maybe_used_by_stmt_p' - * 'stmt_may_clobber_ref_p' - - In addition to those two kind of statement walkers are available - walking statements related to a reference ref. - 'walk_non_aliased_vuses' walks over dominating memory defining - statements and calls back if the statement does not clobber ref - providing the non-aliased VUSE. The walk stops at the first - clobbering statement or if asked to. 'walk_aliased_vdefs' walks - over dominating memory defining statements and calls back on each - statement clobbering ref providing its aliasing VDEF. The walk - stops if asked to. - - -File: gccint.info, Node: Memory model, Prev: Alias analysis, Up: Tree SSA - -12.5 Memory model -================= - -The memory model used by the middle-end models that of the C/C++ -languages. The middle-end has the notion of an effective type of a -memory region which is used for type-based alias analysis. - - The following is a refinement of ISO C99 6.5/6, clarifying the block -copy case to follow common sense and extending the concept of a dynamic -effective type to objects with a declared type as required for C++. - - The effective type of an object for an access to its stored value is - the declared type of the object or the effective type determined by - a previous store to it. If a value is stored into an object through - an lvalue having a type that is not a character type, then the - type of the lvalue becomes the effective type of the object for that - access and for subsequent accesses that do not modify the stored value. - If a value is copied into an object using memcpy or memmove, - or is copied as an array of character type, then the effective type - of the modified object for that access and for subsequent accesses that - do not modify the value is undetermined. For all other accesses to an - object, the effective type of the object is simply the type of the - lvalue used for the access. - - -File: gccint.info, Node: RTL, Next: Control Flow, Prev: Tree SSA, Up: Top - -13 RTL Representation -********************* - -The last part of the compiler work is done on a low-level 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 'asm' with operands. -* Debug Information:: Expressions representing debugging information. -* 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. - - -File: gccint.info, Node: RTL Objects, Next: RTL Classes, Up: RTL - -13.1 RTL Object Types -===================== - -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 'rtx'. - - An integer is simply an 'int'; their written form uses decimal digits. -A wide integer is an integral object whose type is 'HOST_WIDE_INT'; -their written form uses decimal digits. - - A string is a sequence of characters. In core it is represented as a -'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 '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 ('[...]') -surrounding the elements, in sequence and with whitespace separating -them. Vectors of length zero are not created; null pointers are used -instead. - - Expressions are classified by "expression codes" (also called RTX -codes). The expression code is a name defined in '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 'GET_CODE (X)' and altered with -'PUT_CODE (X, 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 'subreg', -the first operand is to be regarded as an expression and the second -operand as an integer. In an expression of code 'plus', there are two -operands, both of which are to be regarded as expressions. In a -'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 '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: 'const_int'. - - In a few contexts a null pointer is valid where an expression is -normally wanted. The written form of this is '(nil)'. - - -File: gccint.info, Node: RTL Classes, Next: Accessors, Prev: RTL Objects, Up: RTL - -13.2 RTL Classes and Formats -============================ - -The various expression codes are divided into several "classes", which -are represented by single characters. You can determine the class of an -RTX code with the macro 'GET_RTX_CLASS (CODE)'. Currently, 'rtl.def' -defines these classes: - -'RTX_OBJ' - An RTX code that represents an actual object, such as a register - ('REG') or a memory location ('MEM', 'SYMBOL_REF'). 'LO_SUM') is - also included; instead, 'SUBREG' and 'STRICT_LOW_PART' are not in - this class, but in class 'x'. - -'RTX_CONST_OBJ' - An RTX code that represents a constant object. 'HIGH' is also - included in this class. - -'RTX_COMPARE' - An RTX code for a non-symmetric comparison, such as 'GEU' or 'LT'. - -'RTX_COMM_COMPARE' - An RTX code for a symmetric (commutative) comparison, such as 'EQ' - or 'ORDERED'. - -'RTX_UNARY' - An RTX code for a unary arithmetic operation, such as 'NEG', 'NOT', - or 'ABS'. This category also includes value extension (sign or - zero) and conversions between integer and floating point. - -'RTX_COMM_ARITH' - An RTX code for a commutative binary operation, such as 'PLUS' or - 'AND'. 'NE' and 'EQ' are comparisons, so they have class '<'. - -'RTX_BIN_ARITH' - An RTX code for a non-commutative binary operation, such as - 'MINUS', 'DIV', or 'ASHIFTRT'. - -'RTX_BITFIELD_OPS' - An RTX code for a bit-field operation. Currently only - 'ZERO_EXTRACT' and 'SIGN_EXTRACT'. These have three inputs and are - lvalues (so they can be used for insertion as well). *Note - Bit-Fields::. - -'RTX_TERNARY' - An RTX code for other three input operations. Currently only - 'IF_THEN_ELSE', 'VEC_MERGE', 'SIGN_EXTRACT', 'ZERO_EXTRACT', and - 'FMA'. - -'RTX_INSN' - An RTX code for an entire instruction: 'INSN', 'JUMP_INSN', and - 'CALL_INSN'. *Note Insns::. - -'RTX_MATCH' - An RTX code for something that matches in insns, such as - 'MATCH_DUP'. These only occur in machine descriptions. - -'RTX_AUTOINC' - An RTX code for an auto-increment addressing mode, such as - 'POST_INC'. - -'RTX_EXTRA' - All other RTX codes. This category includes the remaining codes - used only in machine descriptions ('DEFINE_*', etc.). It also - includes all the codes describing side effects ('SET', 'USE', - 'CLOBBER', etc.) and the non-insns that may appear on an insn - chain, such as 'NOTE', 'BARRIER', and 'CODE_LABEL'. 'SUBREG' is - also part of this class. - - For each expression code, 'rtl.def' specifies the number of contained -objects and their kinds using a sequence of characters called the -"format" of the expression code. For example, the format of 'subreg' is -'ei'. - - These are the most commonly used format characters: - -'e' - An expression (actually a pointer to an expression). - -'i' - An integer. - -'w' - A wide integer. - -'s' - A string. - -'E' - A vector of expressions. - - A few other format characters are used occasionally: - -'u' - 'u' is equivalent to 'e' except that it is printed differently in - debugging dumps. It is used for pointers to insns. - -'n' - 'n' is equivalent to 'i' except that it is printed differently in - debugging dumps. It is used for the line number or code number of - a 'note' insn. - -'S' - 'S' indicates a string which is optional. In the RTL objects in - core, 'S' is equivalent to 's', but when the object is read, from - an 'md' file, the string value of this operand may be omitted. An - omitted string is taken to be the null string. - -'V' - 'V' indicates a vector which is optional. In the RTL objects in - core, 'V' is equivalent to 'E', but when the object is read from an - 'md' file, the vector value of this operand may be omitted. An - omitted vector is effectively the same as a vector of no elements. - -'B' - 'B' indicates a pointer to basic block structure. - -'0' - '0' means a slot whose contents do not fit any normal category. - '0' slots are not printed at all in dumps, and are often used in - special ways by small parts of the compiler. - - There are macros to get the number of operands and the format of an -expression code: - -'GET_RTX_LENGTH (CODE)' - Number of operands of an RTX of code CODE. - -'GET_RTX_FORMAT (CODE)' - The format of an RTX of code CODE, as a C string. - - Some classes of RTX codes always have the same format. For example, it -is safe to assume that all comparison operations have format 'ee'. - -'1' - All codes of this class have format 'e'. - -'<' -'c' -'2' - All codes of these classes have format 'ee'. - -'b' -'3' - All codes of these classes have format 'eee'. - -'i' - All codes of this class have formats that begin with 'iuueiee'. - *Note Insns::. Note that not all RTL objects linked onto an insn - chain are of class 'i'. - -'o' -'m' -'x' - You can make no assumptions about the format of these codes. - - -File: gccint.info, Node: Accessors, Next: Special Accessors, Prev: RTL Classes, Up: RTL - -13.3 Access to Operands -======================= - -Operands of expressions are accessed using the macros 'XEXP', 'XINT', -'XWINT' and 'XSTR'. Each of these macros takes two arguments: an -expression-pointer (RTX) and an operand number (counting from zero). -Thus, - - XEXP (X, 2) - -accesses operand 2 of expression X, as an expression. - - XINT (X, 2) - -accesses the same operand as an integer. '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 X is a 'subreg' expression, you know that it has two -operands which can be correctly accessed as 'XEXP (X, 0)' and 'XINT (X, -1)'. If you did 'XINT (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 '(int) XEXP (X, 0)'. 'XEXP (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 'XEXP -(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 'XVEC' to get the vector-pointer itself, or the macros -'XVECEXP' and 'XVECLEN' to access the elements and length of a vector. - -'XVEC (EXP, IDX)' - Access the vector-pointer which is operand number IDX in EXP. - -'XVECLEN (EXP, IDX)' - Access the length (number of elements) in the vector which is in - operand number IDX in EXP. This value is an 'int'. - -'XVECEXP (EXP, IDX, ELTNUM)' - Access element number ELTNUM in the vector which is in operand - number IDX in EXP. This value is an RTX. - - It is up to you to make sure that ELTNUM is not negative and is - less than 'XVECLEN (EXP, IDX)'. - - 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. - - -File: gccint.info, Node: Special Accessors, Next: Flags, Prev: Accessors, Up: RTL - -13.4 Access to Special Operands -=============================== - -Some RTL nodes have special annotations associated with them. - -'MEM' - 'MEM_ALIAS_SET (X)' - If 0, X is not in any alias set, and may alias anything. - Otherwise, X can only alias '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 'alias_sets_conflict_p'. - - 'MEM_EXPR (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 - 'COMPONENT_REF', in which case this is some field reference, - and 'TREE_OPERAND (X, 0)' contains the declaration, or another - 'COMPONENT_REF', or null if there is no compile-time object - associated with the reference. - - 'MEM_OFFSET_KNOWN_P (X)' - True if the offset of the memory reference from 'MEM_EXPR' is - known. 'MEM_OFFSET (X)' provides the offset if so. - - 'MEM_OFFSET (X)' - The offset from the start of 'MEM_EXPR'. The value is only - valid if 'MEM_OFFSET_KNOWN_P (X)' is true. - - 'MEM_SIZE_KNOWN_P (X)' - True if the size of the memory reference is known. 'MEM_SIZE - (X)' provides its size if so. - - 'MEM_SIZE (X)' - The size in bytes of the memory reference. This is mostly - relevant for 'BLKmode' references as otherwise the size is - implied by the mode. The value is only valid if - 'MEM_SIZE_KNOWN_P (X)' is true. - - 'MEM_ALIGN (X)' - The known alignment in bits of the memory reference. - - 'MEM_ADDR_SPACE (X)' - The address space of the memory reference. This will commonly - be zero for the generic address space. - -'REG' - 'ORIGINAL_REGNO (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. - - 'REG_EXPR (X)' - If this register is known to hold the value of some user-level - declaration, this is that tree node. - - 'REG_OFFSET (X)' - If this register is known to hold the value of some user-level - declaration, this is the offset into that logical storage. - -'SYMBOL_REF' - 'SYMBOL_REF_DECL (X)' - If the 'symbol_ref' X was created for a 'VAR_DECL' or a - 'FUNCTION_DECL', that tree is recorded here. If this value is - null, then X was created by back end code generation routines, - and there is no associated front end symbol table entry. - - 'SYMBOL_REF_DECL' may also point to a tree of class ''c'', - that is, some sort of constant. In this case, the - 'symbol_ref' is an entry in the per-file constant pool; again, - there is no associated front end symbol table entry. - - 'SYMBOL_REF_CONSTANT (X)' - If 'CONSTANT_POOL_ADDRESS_P (X)' is true, this is the constant - pool entry for X. It is null otherwise. - - 'SYMBOL_REF_DATA (X)' - A field of opaque type used to store 'SYMBOL_REF_DECL' or - 'SYMBOL_REF_CONSTANT'. - - 'SYMBOL_REF_FLAGS (X)' - In a '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: - - 'SYMBOL_FLAG_FUNCTION' - Set if the symbol refers to a function. - - 'SYMBOL_FLAG_LOCAL' - Set if the symbol is local to this "module". See - 'TARGET_BINDS_LOCAL_P'. - - 'SYMBOL_FLAG_EXTERNAL' - Set if this symbol is not defined in this translation - unit. Note that this is not the inverse of - 'SYMBOL_FLAG_LOCAL'. - - 'SYMBOL_FLAG_SMALL' - Set if the symbol is located in the small data section. - See 'TARGET_IN_SMALL_DATA_P'. - - 'SYMBOL_REF_TLS_MODEL (X)' - This is a multi-bit field accessor that returns the - 'tls_model' to be used for a thread-local storage symbol. - It returns zero for non-thread-local symbols. - - 'SYMBOL_FLAG_HAS_BLOCK_INFO' - Set if the symbol has 'SYMBOL_REF_BLOCK' and - 'SYMBOL_REF_BLOCK_OFFSET' fields. - - 'SYMBOL_FLAG_ANCHOR' - Set if the symbol is used as a section anchor. "Section - anchors" are symbols that have a known position within an - 'object_block' and that can be used to access nearby - members of that block. They are used to implement - '-fsection-anchors'. - - If this flag is set, then 'SYMBOL_FLAG_HAS_BLOCK_INFO' - will be too. - - Bits beginning with 'SYMBOL_FLAG_MACH_DEP' are available for - the target's use. - -'SYMBOL_REF_BLOCK (X)' - If 'SYMBOL_REF_HAS_BLOCK_INFO_P (X)', this is the 'object_block' - structure to which the symbol belongs, or 'NULL' if it has not been - assigned a block. - -'SYMBOL_REF_BLOCK_OFFSET (X)' - If 'SYMBOL_REF_HAS_BLOCK_INFO_P (X)', this is the offset of X from - the first object in 'SYMBOL_REF_BLOCK (X)'. The value is negative - if X has not yet been assigned to a block, or it has not been given - an offset within that block. - - -File: gccint.info, Node: Flags, Next: Machine Modes, Prev: Special Accessors, Up: RTL - -13.5 Flags in an 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. - -'CONSTANT_POOL_ADDRESS_P (X)' - Nonzero in a 'symbol_ref' if it refers to part of the current - function's constant pool. For most targets these addresses are in - a '.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 'unchanging' field and printed as '/u'. - -'RTL_CONST_CALL_P (X)' - In a 'call_insn' indicates that the insn represents a call to a - const function. Stored in the 'unchanging' field and printed as - '/u'. - -'RTL_PURE_CALL_P (X)' - In a 'call_insn' indicates that the insn represents a call to a - pure function. Stored in the 'return_val' field and printed as - '/i'. - -'RTL_CONST_OR_PURE_CALL_P (X)' - In a 'call_insn', true if 'RTL_CONST_CALL_P' or 'RTL_PURE_CALL_P' - is true. - -'RTL_LOOPING_CONST_OR_PURE_CALL_P (X)' - In a 'call_insn' indicates that the insn represents a possibly - infinite looping call to a const or pure function. Stored in the - 'call' field and printed as '/c'. Only true if one of - 'RTL_CONST_CALL_P' or 'RTL_PURE_CALL_P' is true. - -'INSN_ANNULLED_BRANCH_P (X)' - In a 'jump_insn', 'call_insn', or 'insn' indicates that the branch - is an annulling one. See the discussion under 'sequence' below. - Stored in the 'unchanging' field and printed as '/u'. - -'INSN_DELETED_P (X)' - In an 'insn', 'call_insn', 'jump_insn', 'code_label', - 'jump_table_data', 'barrier', or 'note', nonzero if the insn has - been deleted. Stored in the 'volatil' field and printed as '/v'. - -'INSN_FROM_TARGET_P (X)' - In an 'insn' or 'jump_insn' or '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 'INSN_ANNULLED_BRANCH_P' set, this insn will - only be executed if the branch is taken. For annulled branches - with 'INSN_FROM_TARGET_P' clear, the insn will be executed only if - the branch is not taken. When 'INSN_ANNULLED_BRANCH_P' is not set, - this insn will always be executed. Stored in the 'in_struct' field - and printed as '/s'. - -'LABEL_PRESERVE_P (X)' - In a 'code_label' or '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 'in_struct' field and printed as '/s'. - -'LABEL_REF_NONLOCAL_P (X)' - In 'label_ref' and 'reg_label' expressions, nonzero if this is a - reference to a non-local label. Stored in the 'volatil' field and - printed as '/v'. - -'MEM_KEEP_ALIAS_SET_P (X)' - In '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 'jump' field and printed as '/j'. - -'MEM_VOLATILE_P (X)' - In 'mem', 'asm_operands', and 'asm_input' expressions, nonzero for - volatile memory references. Stored in the 'volatil' field and - printed as '/v'. - -'MEM_NOTRAP_P (X)' - In 'mem', nonzero for memory references that will not trap. Stored - in the 'call' field and printed as '/c'. - -'MEM_POINTER (X)' - Nonzero in a 'mem' if the memory reference holds a pointer. Stored - in the 'frame_related' field and printed as '/f'. - -'REG_FUNCTION_VALUE_P (X)' - Nonzero in a '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 'return_val' field and printed as '/i'. - -'REG_POINTER (X)' - Nonzero in a 'reg' if the register holds a pointer. Stored in the - 'frame_related' field and printed as '/f'. - -'REG_USERVAR_P (X)' - In a '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 'volatil' field and printed as '/v'. - - The same hard register may be used also for collecting the values - of functions called by this one, but 'REG_FUNCTION_VALUE_P' is zero - in this kind of use. - -'RTX_FRAME_RELATED_P (X)' - Nonzero in an 'insn', 'call_insn', 'jump_insn', 'barrier', or '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 'frame_related' field - and printed as '/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 'RTX_FRAME_RELATED_P'. - - If the marked instruction is overly complex (defined in terms of - what 'dwarf2out_frame_debug_expr' can handle), you will also have - to create a '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 - 'dwarf2out_frame_debug_expr' can handle. - - This flag is required for exception handling support on targets - with RTL prologues. - -'MEM_READONLY_P (X)' - Nonzero in a '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 transferred - from the runtime loader to the application, this memory will never - be subsequently modified. - - Stored in the 'unchanging' field and printed as '/u'. - -'SCHED_GROUP_P (X)' - During instruction scheduling, in an 'insn', 'call_insn', - 'jump_insn' or 'jump_table_data', 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, 'use' insns before a - 'call_insn' may not be separated from the 'call_insn'. Stored in - the 'in_struct' field and printed as '/s'. - -'SET_IS_RETURN_P (X)' - For a 'set', nonzero if it is for a return. Stored in the 'jump' - field and printed as '/j'. - -'SIBLING_CALL_P (X)' - For a 'call_insn', nonzero if the insn is a sibling call. Stored - in the 'jump' field and printed as '/j'. - -'STRING_POOL_ADDRESS_P (X)' - For a 'symbol_ref' expression, nonzero if it addresses this - function's string constant pool. Stored in the 'frame_related' - field and printed as '/f'. - -'SUBREG_PROMOTED_UNSIGNED_P (X)' - Returns a value greater then zero for a 'subreg' that has - '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 'ptr_extend' - instruction. Stored in the 'unchanging' field and 'volatil' field, - printed as '/u' and '/v'. This macro may only be used to get the - value it may not be used to change the value. Use - 'SUBREG_PROMOTED_UNSIGNED_SET' to change the value. - -'SUBREG_PROMOTED_UNSIGNED_SET (X)' - Set the 'unchanging' and 'volatil' fields in a 'subreg' to reflect - zero, sign, or other extension. If 'volatil' is zero, then - 'unchanging' as nonzero means zero extension and as zero means sign - extension. If 'volatil' is nonzero then some other type of - extension was done via the 'ptr_extend' instruction. - -'SUBREG_PROMOTED_VAR_P (X)' - Nonzero in a 'subreg' if it was made when accessing an object that - was promoted to a wider mode in accord with the 'PROMOTED_MODE' - machine description macro (*note Storage Layout::). In this case, - the mode of the 'subreg' is the declared mode of the object and the - mode of '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 - 'in_struct' field and printed as '/s'. - -'SYMBOL_REF_USED (X)' - In a 'symbol_ref', indicates that X has been used. This is - normally only used to ensure that X is only declared external once. - Stored in the 'used' field. - -'SYMBOL_REF_WEAK (X)' - In a 'symbol_ref', indicates that X has been declared weak. Stored - in the 'return_val' field and printed as '/i'. - -'SYMBOL_REF_FLAG (X)' - In a 'symbol_ref', this is used as a flag for machine-specific - purposes. Stored in the 'volatil' field and printed as '/v'. - - Most uses of 'SYMBOL_REF_FLAG' are historic and may be subsumed by - 'SYMBOL_REF_FLAGS'. Certainly use of 'SYMBOL_REF_FLAGS' is - mandatory if the target requires more than one bit of storage. - -'PREFETCH_SCHEDULE_BARRIER_P (X)' - In a 'prefetch', indicates that the prefetch is a scheduling - barrier. No other INSNs will be moved over it. Stored in the - 'volatil' field and printed as '/v'. - - These are the fields to which the above macros refer: - -'call' - In a 'mem', 1 means that the memory reference will not trap. - - In a 'call', 1 means that this pure or const call may possibly - infinite loop. - - In an RTL dump, this flag is represented as '/c'. - -'frame_related' - In an 'insn' or '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 'reg' expressions, 1 means that the register holds a pointer. - - In 'mem' expressions, 1 means that the memory reference holds a - pointer. - - In 'symbol_ref' expressions, 1 means that the reference addresses - this function's string constant pool. - - In an RTL dump, this flag is represented as '/f'. - -'in_struct' - In 'reg' expressions, it is 1 if the register has its entire life - contained within the test expression of some loop. - - In 'subreg' expressions, 1 means that the 'subreg' is accessing an - object that has had its mode promoted from a wider mode. - - In 'label_ref' expressions, 1 means that the referenced label is - outside the innermost loop containing the insn in which the - 'label_ref' was found. - - In '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 'note' of type 'NOTE_INSN_DELETED_LABEL'. - - In an 'insn' during dead-code elimination, 1 means that the insn is - dead code. - - In an 'insn' or '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 '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 '/s'. - -'return_val' - In '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 'symbol_ref' expressions, 1 means the referenced symbol is weak. - - In 'call' expressions, 1 means the call is pure. - - In an RTL dump, this flag is represented as '/i'. - -'jump' - In a 'mem' expression, 1 means we should keep the alias set for - this mem unchanged when we access a component. - - In a 'set', 1 means it is for a return. - - In a 'call_insn', 1 means it is a sibling call. - - In an RTL dump, this flag is represented as '/j'. - -'unchanging' - In 'reg' and 'mem' expressions, 1 means that the value of the - expression never changes. - - In 'subreg' expressions, it is 1 if the 'subreg' references an - unsigned object whose mode has been promoted to a wider mode. - - In an 'insn' or 'jump_insn' in the delay slot of a branch - instruction, 1 means an annulling branch should be used. - - In a 'symbol_ref' expression, 1 means that this symbol addresses - something in the per-function constant pool. - - In a 'call_insn' 1 means that this instruction is a call to a const - function. - - In an RTL dump, this flag is represented as '/u'. - -'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 (*note - Sharing::). - - For a '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 'symbol_ref', it indicates that an external declaration for - the symbol has already been written. - -'volatil' - In a 'mem', 'asm_operands', or 'asm_input' expression, it is 1 if - the memory reference is volatile. Volatile memory references may - not be deleted, reordered or combined. - - In a 'symbol_ref' expression, it is used for machine-specific - purposes. - - In a 'reg' expression, it is 1 if the value is a user-level - variable. 0 indicates an internal compiler temporary. - - In an 'insn', 1 means the insn has been deleted. - - In 'label_ref' and 'reg_label' expressions, 1 means a reference to - a non-local label. - - In 'prefetch' expressions, 1 means that the containing insn is a - scheduling barrier. - - In an RTL dump, this flag is represented as '/v'. - - -File: gccint.info, Node: Machine Modes, Next: Constants, Prev: Flags, Up: RTL - -13.6 Machine Modes -================== - -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, 'enum machine_mode', defined in '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 'mode' which appear at the end of each machine mode -name are omitted. For example, '(reg:SI 38)' is a 'reg' expression with -machine mode 'SImode'. If the mode is 'VOIDmode', it is not written at -all. - - Here is a table of machine modes. The term "byte" below refers to an -object of 'BITS_PER_UNIT' bits (*note Storage Layout::). - -'BImode' - "Bit" mode represents a single bit, for predicate registers. - -'QImode' - "Quarter-Integer" mode represents a single byte treated as an - integer. - -'HImode' - "Half-Integer" mode represents a two-byte integer. - -'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. - -'SImode' - "Single Integer" mode represents a four-byte integer. - -'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. - -'DImode' - "Double Integer" mode represents an eight-byte integer. - -'TImode' - "Tetra Integer" (?) mode represents a sixteen-byte integer. - -'OImode' - "Octa Integer" (?) mode represents a thirty-two-byte integer. - -'XImode' - "Hexadeca Integer" (?) mode represents a sixty-four-byte integer. - -'QFmode' - "Quarter-Floating" mode represents a quarter-precision (single - byte) floating point number. - -'HFmode' - "Half-Floating" mode represents a half-precision (two byte) - floating point number. - -'TQFmode' - "Three-Quarter-Floating" (?) mode represents a - three-quarter-precision (three byte) floating point number. - -'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. - -'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. - -'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. - -'SDmode' - "Single Decimal Floating" mode represents a four byte decimal - floating point number (as distinct from conventional binary - floating point). - -'DDmode' - "Double Decimal Floating" mode represents an eight byte decimal - floating point number. - -'TDmode' - "Tetra Decimal Floating" mode represents a sixteen byte decimal - floating point number all 128 of whose bits are meaningful. - -'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. - -'QQmode' - "Quarter-Fractional" mode represents a single byte treated as a - signed fractional number. The default format is "s.7". - -'HQmode' - "Half-Fractional" mode represents a two-byte signed fractional - number. The default format is "s.15". - -'SQmode' - "Single Fractional" mode represents a four-byte signed fractional - number. The default format is "s.31". - -'DQmode' - "Double Fractional" mode represents an eight-byte signed fractional - number. The default format is "s.63". - -'TQmode' - "Tetra Fractional" mode represents a sixteen-byte signed fractional - number. The default format is "s.127". - -'UQQmode' - "Unsigned Quarter-Fractional" mode represents a single byte treated - as an unsigned fractional number. The default format is ".8". - -'UHQmode' - "Unsigned Half-Fractional" mode represents a two-byte unsigned - fractional number. The default format is ".16". - -'USQmode' - "Unsigned Single Fractional" mode represents a four-byte unsigned - fractional number. The default format is ".32". - -'UDQmode' - "Unsigned Double Fractional" mode represents an eight-byte unsigned - fractional number. The default format is ".64". - -'UTQmode' - "Unsigned Tetra Fractional" mode represents a sixteen-byte unsigned - fractional number. The default format is ".128". - -'HAmode' - "Half-Accumulator" mode represents a two-byte signed accumulator. - The default format is "s8.7". - -'SAmode' - "Single Accumulator" mode represents a four-byte signed - accumulator. The default format is "s16.15". - -'DAmode' - "Double Accumulator" mode represents an eight-byte signed - accumulator. The default format is "s32.31". - -'TAmode' - "Tetra Accumulator" mode represents a sixteen-byte signed - accumulator. The default format is "s64.63". - -'UHAmode' - "Unsigned Half-Accumulator" mode represents a two-byte unsigned - accumulator. The default format is "8.8". - -'USAmode' - "Unsigned Single Accumulator" mode represents a four-byte unsigned - accumulator. The default format is "16.16". - -'UDAmode' - "Unsigned Double Accumulator" mode represents an eight-byte - unsigned accumulator. The default format is "32.32". - -'UTAmode' - "Unsigned Tetra Accumulator" mode represents a sixteen-byte - unsigned accumulator. The default format is "64.64". - -'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 'cc0' (*note Condition Code::). - -'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, - 'BLKmode' will not appear in RTL. - -'VOIDmode' - Void mode means the absence of a mode or an unspecified mode. For - example, RTL expressions of code 'const_int' have mode 'VOIDmode' - because they can be taken to have whatever mode the context - requires. In debugging dumps of RTL, 'VOIDmode' is expressed by - the absence of any mode. - -'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 'QFmode', - 'HFmode', 'SFmode', 'DFmode', 'XFmode', and 'TFmode', respectively. - -'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 'QImode', 'HImode', - 'SImode', 'DImode', 'TImode', and 'OImode', respectively. - - The machine description defines 'Pmode' as a C macro which expands into -the machine mode used for addresses. Normally this is the mode whose -size is 'BITS_PER_WORD', 'SImode' on 32-bit machines. - - The only modes which a machine description must support are 'QImode', -and the modes corresponding to 'BITS_PER_WORD', 'FLOAT_TYPE_SIZE' and -'DOUBLE_TYPE_SIZE'. The compiler will attempt to use 'DImode' for -8-byte structures and unions, but this can be prevented by overriding -the definition of 'MAX_FIXED_MODE_SIZE'. Alternatively, you can have -the compiler use 'TImode' for 16-byte structures and unions. Likewise, -you can arrange for the C type 'short int' to avoid using 'HImode'. - - 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 'enum mode_class' defined in 'machmode.h'. The -possible mode classes are: - -'MODE_INT' - Integer modes. By default these are 'BImode', 'QImode', 'HImode', - 'SImode', 'DImode', 'TImode', and 'OImode'. - -'MODE_PARTIAL_INT' - The "partial integer" modes, 'PQImode', 'PHImode', 'PSImode' and - 'PDImode'. - -'MODE_FLOAT' - Floating point modes. By default these are 'QFmode', 'HFmode', - 'TQFmode', 'SFmode', 'DFmode', 'XFmode' and 'TFmode'. - -'MODE_DECIMAL_FLOAT' - Decimal floating point modes. By default these are 'SDmode', - 'DDmode' and 'TDmode'. - -'MODE_FRACT' - Signed fractional modes. By default these are 'QQmode', 'HQmode', - 'SQmode', 'DQmode' and 'TQmode'. - -'MODE_UFRACT' - Unsigned fractional modes. By default these are 'UQQmode', - 'UHQmode', 'USQmode', 'UDQmode' and 'UTQmode'. - -'MODE_ACCUM' - Signed accumulator modes. By default these are 'HAmode', 'SAmode', - 'DAmode' and 'TAmode'. - -'MODE_UACCUM' - Unsigned accumulator modes. By default these are 'UHAmode', - 'USAmode', 'UDAmode' and 'UTAmode'. - -'MODE_COMPLEX_INT' - Complex integer modes. (These are not currently implemented). - -'MODE_COMPLEX_FLOAT' - Complex floating point modes. By default these are 'QCmode', - 'HCmode', 'SCmode', 'DCmode', 'XCmode', and 'TCmode'. - -'MODE_FUNCTION' - Algol or Pascal function variables including a static chain. - (These are not currently implemented). - -'MODE_CC' - Modes representing condition code values. These are 'CCmode' plus - any 'CC_MODE' modes listed in the 'MACHINE-modes.def'. *Note Jump - Patterns::, also see *note Condition Code::. - -'MODE_RANDOM' - This is a catchall mode class for modes which don't fit into the - above classes. Currently 'VOIDmode' and 'BLKmode' are in - 'MODE_RANDOM'. - - Here are some C macros that relate to machine modes: - -'GET_MODE (X)' - Returns the machine mode of the RTX X. - -'PUT_MODE (X, NEWMODE)' - Alters the machine mode of the RTX X to be NEWMODE. - -'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. - -'GET_MODE_NAME (M)' - Returns the name of mode M as a string. - -'GET_MODE_CLASS (M)' - Returns the mode class of mode M. - -'GET_MODE_WIDER_MODE (M)' - Returns the next wider natural mode. For example, the expression - 'GET_MODE_WIDER_MODE (QImode)' returns 'HImode'. - -'GET_MODE_SIZE (M)' - Returns the size in bytes of a datum of mode M. - -'GET_MODE_BITSIZE (M)' - Returns the size in bits of a datum of mode M. - -'GET_MODE_IBIT (M)' - Returns the number of integral bits of a datum of fixed-point mode - M. - -'GET_MODE_FBIT (M)' - Returns the number of fractional bits of a datum of fixed-point - mode M. - -'GET_MODE_MASK (M)' - Returns a bitmask containing 1 for all bits in a word that fit - within mode M. This macro can only be used for modes whose bitsize - is less than or equal to 'HOST_BITS_PER_INT'. - -'GET_MODE_ALIGNMENT (M)' - Return the required alignment, in bits, for an object of mode M. - -'GET_MODE_UNIT_SIZE (M)' - Returns the size in bytes of the subunits of a datum of mode M. - This is the same as 'GET_MODE_SIZE' except in the case of complex - modes. For them, the unit size is the size of the real or - imaginary part. - -'GET_MODE_NUNITS (M)' - Returns the number of units contained in a mode, i.e., - 'GET_MODE_SIZE' divided by 'GET_MODE_UNIT_SIZE'. - -'GET_CLASS_NARROWEST_MODE (C)' - Returns the narrowest mode in mode class C. - - The following 3 variables are defined on every target. They can be -used to allocate buffers that are guaranteed to be large enough to hold -any value that can be represented on the target. The first two can be -overridden by defining them in the target's mode.def file, however, the -value must be a constant that can determined very early in the -compilation process. The third symbol cannot be overridden. - -'BITS_PER_UNIT' - The number of bits in an addressable storage unit (byte). If you - do not define this, the default is 8. - -'MAX_BITSIZE_MODE_ANY_INT' - The maximum bitsize of any mode that is used in integer math. This - should be overridden by the target if it uses large integers as - containers for larger vectors but otherwise never uses the contents - to compute integer values. - -'MAX_BITSIZE_MODE_ANY_MODE' - The bitsize of the largest mode on the target. - - The global variables 'byte_mode' and 'word_mode' contain modes whose -classes are 'MODE_INT' and whose bitsizes are either 'BITS_PER_UNIT' or -'BITS_PER_WORD', respectively. On 32-bit machines, these are 'QImode' -and 'SImode', respectively. - - -File: gccint.info, Node: Constants, Next: Regs and Memory, Prev: Machine Modes, Up: RTL - -13.7 Constant Expression Types -============================== - -The simplest RTL expressions are those that represent constant values. - -'(const_int I)' - This type of expression represents the integer value I. I is - customarily accessed with the macro 'INTVAL' as in 'INTVAL (EXP)', - which is equivalent to 'XWINT (EXP, 0)'. - - Constants generated for modes with fewer bits than in - 'HOST_WIDE_INT' must be sign extended to full width (e.g., with - 'gen_int_mode'). For constants for modes with more bits than in - 'HOST_WIDE_INT' the implied high order bits of that constant are - copies of the top bit. Note however that values are neither - inherently signed nor inherently unsigned; where necessary, - signedness is determined by the rtl operation instead. - - There is only one expression object for the integer value zero; it - is the value of the variable 'const0_rtx'. Likewise, the only - expression for integer value one is found in 'const1_rtx', the only - expression for integer value two is found in 'const2_rtx', and the - only expression for integer value negative one is found in - 'constm1_rtx'. Any attempt to create an expression of code - 'const_int' and value zero, one, two or negative one will return - 'const0_rtx', 'const1_rtx', 'const2_rtx' or 'constm1_rtx' as - appropriate. - - Similarly, there is only one object for the integer whose value is - 'STORE_FLAG_VALUE'. It is found in 'const_true_rtx'. If - 'STORE_FLAG_VALUE' is one, 'const_true_rtx' and 'const1_rtx' will - point to the same object. If 'STORE_FLAG_VALUE' is -1, - 'const_true_rtx' and 'constm1_rtx' will point to the same object. - -'(const_double:M I0 I1 ...)' - Represents either a floating-point constant of mode M or an integer - constant too large to fit into '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, M will be 'VOIDmode'. For integral values constants - for modes with more bits than twice the number in 'HOST_WIDE_INT' - the implied high order bits of that constant are copies of the top - bit of 'CONST_DOUBLE_HIGH'. Note however that integral values are - neither inherently signed nor inherently unsigned; where necessary, - signedness is determined by the rtl operation instead. - - If M is 'VOIDmode', the bits of the value are stored in I0 and I1. - I0 is customarily accessed with the macro 'CONST_DOUBLE_LOW' and I1 - with '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 'REAL_VALUE_TYPE' (*note 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 'REAL_VALUE_TO_TARGET_DOUBLE' and friends (*note Data - Output::). - -'(const_fixed:M ...)' - Represents a fixed-point constant of mode M. The operand is a data - structure of type 'struct fixed_value' and is accessed with the - macro 'CONST_FIXED_VALUE'. The high part of data is accessed with - 'CONST_FIXED_VALUE_HIGH'; the low part is accessed with - 'CONST_FIXED_VALUE_LOW'. - -'(const_vector:M [X0 X1 ...])' - Represents a vector constant. The square brackets stand for the - vector containing the constant elements. X0, X1 and so on are the - 'const_int', 'const_double' or 'const_fixed' elements. - - The number of units in a 'const_vector' is obtained with the macro - 'CONST_VECTOR_NUNITS' as in 'CONST_VECTOR_NUNITS (V)'. - - Individual elements in a vector constant are accessed with the - macro 'CONST_VECTOR_ELT' as in 'CONST_VECTOR_ELT (V, N)' where V is - the vector constant and N is the element desired. - -'(const_string STR)' - Represents a constant string with value STR. Currently this is - used only for insn attributes (*note Insn Attributes::) since - constant strings in C are placed in memory. - -'(symbol_ref:MODE SYMBOL)' - Represents the value of an assembler label for data. SYMBOL is a - string that describes the name of the assembler label. If it - starts with a '*', the label is the rest of SYMBOL not including - the '*'. Otherwise, the label is SYMBOL, usually prefixed with - '_'. - - The 'symbol_ref' contains a mode, which is usually 'Pmode'. - Usually that is the only mode for which a symbol is directly valid. - -'(label_ref:MODE LABEL)' - Represents the value of an assembler label for code. It contains - one operand, an expression, which must be a 'code_label' or a - 'note' of type '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 'label_ref' contains a mode, which is usually 'Pmode'. Usually - that is the only mode for which a label is directly valid. - -'(const:M EXP)' - Represents a constant that is the result of an assembly-time - arithmetic computation. The operand, EXP, is an expression that - contains only constants ('const_int', 'symbol_ref' and 'label_ref' - expressions) combined with 'plus' and 'minus'. However, not all - combinations are valid, since the assembler cannot do arbitrary - arithmetic on relocatable symbols. - - M should be 'Pmode'. - -'(high:M EXP)' - Represents the high-order bits of EXP, usually a '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 'lo_sum' to represent the - typical two-instruction sequence used in RISC machines to reference - a global memory location. - - M should be 'Pmode'. - - The macro 'CONST0_RTX (MODE)' refers to an expression with value 0 in -mode MODE. If mode MODE is of mode class 'MODE_INT', it returns -'const0_rtx'. If mode MODE is of mode class 'MODE_FLOAT', it returns a -'CONST_DOUBLE' expression in mode MODE. Otherwise, it returns a -'CONST_VECTOR' expression in mode MODE. Similarly, the macro -'CONST1_RTX (MODE)' refers to an expression with value 1 in mode MODE -and similarly for 'CONST2_RTX'. The 'CONST1_RTX' and 'CONST2_RTX' -macros are undefined for vector modes. - - -File: gccint.info, Node: Regs and Memory, Next: Arithmetic, Prev: Constants, Up: RTL - -13.8 Registers and Memory -========================= - -Here are the RTL expression types for describing access to machine -registers and to main memory. - -'(reg:M N)' - For small values of the integer N (those that are less than - 'FIRST_PSEUDO_REGISTER'), this stands for a reference to machine - register number N: a "hard register". For larger values of N, it - stands for a temporary value or "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. - - 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 '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 'subreg' - expression is used. - - A '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 'reg' expression. - - Some pseudo register numbers, those within the range of - 'FIRST_VIRTUAL_REGISTER' to '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: - - '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. - - When RTL generation is complete, this virtual register is - replaced by the sum of the register given by - 'ARG_POINTER_REGNUM' and the value of 'FIRST_PARM_OFFSET'. - - 'VIRTUAL_STACK_VARS_REGNUM' - If '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. - - 'VIRTUAL_STACK_VARS_REGNUM' is replaced with the sum of the - register given by 'FRAME_POINTER_REGNUM' and the value - 'STARTING_FRAME_OFFSET'. - - '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. - - This virtual register is replaced by the sum of the register - given by 'STACK_POINTER_REGNUM' and the value - 'STACK_DYNAMIC_OFFSET'. - - '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 - 'STACK_POINTER_REGNUM'). - - This virtual register is replaced by the sum of the register - given by 'STACK_POINTER_REGNUM' and the value - 'STACK_POINTER_OFFSET'. - -'(subreg:M1 REG:M2 BYTENUM)' - - '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 '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, the register must be enclosed in - a 'subreg'. - - There are currently three supported types for the first operand of - a 'subreg': - * pseudo registers This is the most common case. Most 'subreg's - have pseudo 'reg's as their first operand. - - * mem 'subreg's of 'mem' were common in earlier versions of GCC - and are still supported. During the reload pass these are - replaced by plain 'mem's. On machines that do not do - instruction scheduling, use of 'subreg's of 'mem' are still - used, but this is no longer recommended. Such 'subreg's are - considered to be 'register_operand's rather than - 'memory_operand's before and during reload. Because of this, - the scheduling passes cannot properly schedule instructions - with 'subreg's of 'mem', so for machines that do scheduling, - 'subreg's of 'mem' should never be used. To support this, the - combine and recog passes have explicit code to inhibit the - creation of 'subreg's of 'mem' when 'INSN_SCHEDULING' is - defined. - - The use of 'subreg's of 'mem' after the reload pass is an area - that is not well understood and should be avoided. There is - still some code in the compiler to support this, but this code - has possibly rotted. This use of 'subreg's is discouraged and - will most likely not be supported in the future. - - * hard registers It is seldom necessary to wrap hard registers - in 'subreg's; such registers would normally reduce to a single - 'reg' rtx. This use of 'subreg's is discouraged and may not - be supported in the future. - - 'subreg's of 'subreg's are not supported. Using - 'simplify_gen_subreg' is the recommended way to avoid this problem. - - 'subreg's come in two distinct flavors, each having its own usage - and rules: - - Paradoxical subregs - When M1 is strictly wider than M2, the 'subreg' expression is - called "paradoxical". The canonical test for this class of - 'subreg' is: - - GET_MODE_SIZE (M1) > GET_MODE_SIZE (M2) - - Paradoxical 'subreg's can be used as both lvalues and rvalues. - When used as an lvalue, the low-order bits of the source value - are stored in REG and the high-order bits are discarded. When - used as an rvalue, the low-order bits of the 'subreg' are - taken from REG while the high-order bits may or may not be - defined. - - The high-order bits of rvalues are in the following - circumstances: - - * 'subreg's of 'mem' When M2 is smaller than a word, the - macro 'LOAD_EXTEND_OP', can control how the high-order - bits are defined. - - * 'subreg' of 'reg's The upper bits are defined when - 'SUBREG_PROMOTED_VAR_P' is true. - 'SUBREG_PROMOTED_UNSIGNED_P' describes what the upper - bits hold. Such subregs usually represent local - variables, register variables and parameter pseudo - variables that have been promoted to a wider mode. - - BYTENUM is always zero for a paradoxical 'subreg', even on - big-endian targets. - - For example, the paradoxical 'subreg': - - (set (subreg:SI (reg:HI X) 0) Y) - - stores the lower 2 bytes of Y in X and discards the upper 2 - bytes. A subsequent: - - (set Z (subreg:SI (reg:HI X) 0)) - - would set the lower two bytes of Z to Y and set the upper two - bytes to an unknown value assuming 'SUBREG_PROMOTED_VAR_P' is - false. - - Normal subregs - When M1 is at least as narrow as M2 the 'subreg' expression is - called "normal". - - Normal 'subreg's restrict consideration to certain bits of - REG. There are two cases. If M1 is smaller than a word, the - 'subreg' refers to the least-significant part (or "lowpart") - of one word of REG. If M1 is word-sized or greater, the - 'subreg' refers to one or more complete words. - - When used as an lvalue, 'subreg' is a word-based accessor. - Storing to a 'subreg' modifies all the words of REG that - overlap the 'subreg', but it leaves the other words of REG - alone. - - When storing to a normal 'subreg' that is smaller than a word, - the other bits of the referenced word are usually left in an - undefined state. 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 'subreg', use 'strict_low_part' or 'zero_extract' around - the 'subreg'. - - BYTENUM must identify the offset of the first byte of the - 'subreg' from the start of REG, assuming that REG is laid out - in memory order. The memory order of bytes is defined by two - target macros, 'WORDS_BIG_ENDIAN' and 'BYTES_BIG_ENDIAN': - - * '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. - - * '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. - - On a few targets, 'FLOAT_WORDS_BIG_ENDIAN' disagrees with - '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 - 'FLOAT_WORDS_BIG_ENDIAN'. - - Thus, - - (subreg:HI (reg:SI X) 2) - - on a 'BYTES_BIG_ENDIAN', 'UNITS_PER_WORD == 4' target is the - same as - - (subreg:HI (reg:SI X) 0) - - on a little-endian, 'UNITS_PER_WORD == 4' target. Both - 'subreg's access the lower two bytes of register X. - - A 'MODE_PARTIAL_INT' mode behaves as if it were as wide as the - corresponding 'MODE_INT' mode, except that it has an unknown number - of undefined bits. For example: - - (subreg:PSI (reg:SI 0) 0) - - accesses the whole of '(reg:SI 0)', but the exact relationship - between the 'PSImode' value and the 'SImode' value is not defined. - If we assume 'UNITS_PER_WORD <= 4', then the following two - 'subreg's: - - (subreg:PSI (reg:DI 0) 0) - (subreg:PSI (reg:DI 0) 4) - - represent independent 4-byte accesses to the two halves of '(reg:DI - 0)'. Both 'subreg's have an unknown number of undefined bits. - - If 'UNITS_PER_WORD <= 2' then these two 'subreg's: - - (subreg:HI (reg:PSI 0) 0) - (subreg:HI (reg:PSI 0) 2) - - represent independent 2-byte accesses that together span the whole - of '(reg:PSI 0)'. Storing to the first 'subreg' does not affect - the value of the second, and vice versa. '(reg:PSI 0)' has an - unknown number of undefined bits, so the assignment: - - (set (subreg:HI (reg:PSI 0) 0) (reg:HI 4)) - - does not guarantee that '(subreg:HI (reg:PSI 0) 0)' has the value - '(reg:HI 4)'. - - The rules above apply to both pseudo REGs and hard REGs. If the - semantics are not correct for particular combinations of M1, M2 and - hard REG, the target-specific code must ensure that those - combinations are never used. For example: - - CANNOT_CHANGE_MODE_CLASS (M2, M1, CLASS) - - must be true for every class CLASS that includes REG. - - The first operand of a 'subreg' expression is customarily accessed - with the 'SUBREG_REG' macro and the second operand is customarily - accessed with the 'SUBREG_BYTE' macro. - - It has been several years since a platform in which - 'BYTES_BIG_ENDIAN' not equal to 'WORDS_BIG_ENDIAN' has been tested. - Anyone wishing to support such a platform in the future may be - confronted with code rot. - -'(scratch: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 'reg' by either the local register allocator or - the reload pass. - - 'scratch' is usually present inside a 'clobber' operation (*note - Side Effects::). - -'(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: - - * 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, '(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 ('const_int' with value zero; that is to say, - 'const0_rtx'). - - * 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, '(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 'if_then_else' (in a - conditional branch). - - There is only one expression object of code 'cc0'; it is the value - of the variable 'cc0_rtx'. Any attempt to create an expression of - code 'cc0' will return '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 'NOTICE_UPDATE_CC'). - *Note Condition Code::. Only instructions whose sole purpose is to - set the condition code, and instructions that use the condition - code, need mention '(cc0)'. - - On some machines, the condition code register is given a register - number and a 'reg' is used instead of '(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 '(cc0)' in this case). For - examples, search for 'addcc' and 'andcc' in 'sparc.md'. - -'(pc)' - This represents the machine's program counter. It has no operands - and may not have a machine mode. '(pc)' may be validly used only - in certain specific contexts in jump instructions. - - There is only one expression object of code 'pc'; it is the value - of the variable 'pc_rtx'. Any attempt to create an expression of - code 'pc' will return '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. - -'(mem:M ADDR ALIAS)' - This RTX represents a reference to main memory at an address - represented by the expression ADDR. M specifies how large a unit - of memory is accessed. 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 '(mem:BLK (scratch))' is considered to alias all - other memories. Thus it may be used as a memory barrier in - epilogue stack deallocation patterns. - -'(concatM RTX RTX)' - This RTX represents the concatenation of two other RTXs. This is - used for complex values. It should only appear in the RTL attached - to declarations and during RTL generation. It should not appear in - the ordinary insn chain. - -'(concatnM [RTX ...])' - This RTX represents the concatenation of all the RTX to make a - single value. Like 'concat', this should only appear in - declarations, and not in the insn chain. - - -File: gccint.info, Node: Arithmetic, Next: Comparisons, Prev: Regs and Memory, Up: RTL - -13.9 RTL Expressions for Arithmetic -=================================== - -Unless otherwise specified, all the operands of arithmetic expressions -must be valid for mode M. An operand is valid for mode M if it has mode -M, or if it is a 'const_int' or 'const_double' and M is a mode of class -'MODE_INT'. - - For commutative binary operations, constants should be placed in the -second operand. - -'(plus:M X Y)' -'(ss_plus:M X Y)' -'(us_plus:M X Y)' - - These three expressions all represent the sum of the values - represented by X and Y carried out in machine mode M. They differ - in their behavior on overflow of integer modes. 'plus' wraps round - modulo the width of M; 'ss_plus' saturates at the maximum signed - value representable in M; 'us_plus' saturates at the maximum - unsigned value. - -'(lo_sum:M X Y)' - - This expression represents the sum of X and the low-order bits of - Y. It is used with 'high' (*note 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 'Pmode' item minus the number of bits set - by 'high'. - - M should be 'Pmode'. - -'(minus:M X Y)' -'(ss_minus:M X Y)' -'(us_minus:M X Y)' - - These three expressions represent the result of subtracting Y from - X, carried out in mode M. Behavior on overflow is the same as for - the three variants of 'plus' (see above). - -'(compare:M X Y)' - Represents the result of subtracting Y from 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 _only_ way this kind of expression - may validly be used: as a value to be stored in the condition - codes, either '(cc0)' or a register. *Note Comparisons::. - - The mode M is not related to the modes of X and Y, but instead is - the mode of the condition code value. If '(cc0)' is used, it is - 'VOIDmode'. Otherwise it is some mode in class 'MODE_CC', often - 'CCmode'. *Note Condition Code::. If M is 'VOIDmode' or 'CCmode', - the operation returns sufficient information (in an unspecified - format) so that any comparison operator can be applied to the - result of the 'COMPARE' operation. For other modes in class - 'MODE_CC', the operation only returns a subset of this information. - - Normally, X and Y must have the same mode. Otherwise, 'compare' is - valid only if the mode of X is in class 'MODE_INT' and Y is a - 'const_int' or 'const_double' with mode 'VOIDmode'. The mode of X - determines what mode the comparison is to be done in; thus it must - not be '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 'compare' specifying two '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. - -'(neg:M X)' -'(ss_neg:M X)' -'(us_neg:M X)' - These two expressions represent the negation (subtraction from - zero) of the value represented by X, carried out in mode M. They - differ in the behavior on overflow of integer modes. In the case - of 'neg', the negation of the operand may be a number not - representable in mode M, in which case it is truncated to M. - 'ss_neg' and 'us_neg' ensure that an out-of-bounds result saturates - to the maximum or minimum signed or unsigned value. - -'(mult:M X Y)' -'(ss_mult:M X Y)' -'(us_mult:M X Y)' - Represents the signed product of the values represented by X and Y - carried out in machine mode M. 'ss_mult' and 'us_mult' ensure that - an out-of-bounds result saturates to the maximum or minimum signed - or unsigned value. - - Some machines support a multiplication that generates a product - wider than the operands. Write the pattern for this as - - (mult:M (sign_extend:M X) (sign_extend:M Y)) - - where M is wider than the modes of X and Y, which need not be the - same. - - For unsigned widening multiplication, use the same idiom, but with - 'zero_extend' instead of 'sign_extend'. - -'(fma:M X Y Z)' - Represents the 'fma', 'fmaf', and 'fmal' builtin functions that do - a combined multiply of X and Y and then adding toZ without doing an - intermediate rounding step. - -'(div:M X Y)' -'(ss_div:M X Y)' - Represents the quotient in signed division of X by Y, carried out - in machine mode M. If M is a floating point mode, it represents - the exact quotient; otherwise, the integerized quotient. 'ss_div' - ensures that an out-of-bounds result saturates to the maximum or - minimum signed value. - - Some machines have division instructions in which the operands and - quotient widths are not all the same; you should represent such - instructions using 'truncate' and 'sign_extend' as in, - - (truncate:M1 (div:M2 X (sign_extend:M2 Y))) - -'(udiv:M X Y)' -'(us_div:M X Y)' - Like 'div' but represents unsigned division. 'us_div' ensures that - an out-of-bounds result saturates to the maximum or minimum - unsigned value. - -'(mod:M X Y)' -'(umod:M X Y)' - Like 'div' and 'udiv' but represent the remainder instead of the - quotient. - -'(smin:M X Y)' -'(smax:M X Y)' - Represents the smaller (for 'smin') or larger (for 'smax') of X and - Y, interpreted as signed values in mode M. When used with floating - point, if both operands are zeros, or if either operand is 'NaN', - then it is unspecified which of the two operands is returned as the - result. - -'(umin:M X Y)' -'(umax:M X Y)' - Like 'smin' and 'smax', but the values are interpreted as unsigned - integers. - -'(not:M X)' - Represents the bitwise complement of the value represented by X, - carried out in mode M, which must be a fixed-point machine mode. - -'(and:M X Y)' - Represents the bitwise logical-and of the values represented by X - and Y, carried out in machine mode M, which must be a fixed-point - machine mode. - -'(ior:M X Y)' - Represents the bitwise inclusive-or of the values represented by X - and Y, carried out in machine mode M, which must be a fixed-point - mode. - -'(xor:M X Y)' - Represents the bitwise exclusive-or of the values represented by X - and Y, carried out in machine mode M, which must be a fixed-point - mode. - -'(ashift:M X C)' -'(ss_ashift:M X C)' -'(us_ashift:M X C)' - These three expressions represent the result of arithmetically - shifting X left by C places. They differ in their behavior on - overflow of integer modes. An 'ashift' operation is a plain shift - with no special behavior in case of a change in the sign bit; - 'ss_ashift' and 'us_ashift' saturates to the minimum or maximum - representable value if any of the bits shifted out differs from the - final sign bit. - - X have mode M, a fixed-point machine mode. C be a fixed-point mode - or be a constant with mode '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 C is - 'QImode' regardless of M. - -'(lshiftrt:M X C)' -'(ashiftrt:M X C)' - Like 'ashift' but for right shift. Unlike the case for left shift, - these two operations are distinct. - -'(rotate:M X C)' -'(rotatert:M X C)' - Similar but represent left and right rotate. If C is a constant, - use 'rotate'. - -'(abs:M X)' -'(ss_abs:M X)' - Represents the absolute value of X, computed in mode M. 'ss_abs' - ensures that an out-of-bounds result saturates to the maximum - signed value. - -'(sqrt:M X)' - Represents the square root of X, computed in mode M. Most often M - will be a floating point mode. - -'(ffs:M X)' - Represents one plus the index of the least significant 1-bit in X, - represented as an integer of mode M. (The value is zero if X is - zero.) The mode of X must be M or 'VOIDmode'. - -'(clrsb:M X)' - Represents the number of redundant leading sign bits in X, - represented as an integer of mode M, starting at the most - significant bit position. This is one less than the number of - leading sign bits (either 0 or 1), with no special cases. The mode - of X must be M or 'VOIDmode'. - -'(clz:M X)' - Represents the number of leading 0-bits in X, represented as an - integer of mode M, starting at the most significant bit position. - If X is zero, the value is determined by - 'CLZ_DEFINED_VALUE_AT_ZERO' (*note Misc::). Note that this is one - of the few expressions that is not invariant under widening. The - mode of X must be M or 'VOIDmode'. - -'(ctz:M X)' - Represents the number of trailing 0-bits in X, represented as an - integer of mode M, starting at the least significant bit position. - If X is zero, the value is determined by - 'CTZ_DEFINED_VALUE_AT_ZERO' (*note Misc::). Except for this case, - 'ctz(x)' is equivalent to 'ffs(X) - 1'. The mode of X must be M or - 'VOIDmode'. - -'(popcount:M X)' - Represents the number of 1-bits in X, represented as an integer of - mode M. The mode of X must be M or 'VOIDmode'. - -'(parity:M X)' - Represents the number of 1-bits modulo 2 in X, represented as an - integer of mode M. The mode of X must be M or 'VOIDmode'. - -'(bswap:M X)' - Represents the value X with the order of bytes reversed, carried - out in mode M, which must be a fixed-point machine mode. The mode - of X must be M or 'VOIDmode'. - - -File: gccint.info, Node: Comparisons, Next: Bit-Fields, Prev: Arithmetic, Up: RTL - -13.10 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, 'STORE_FLAG_VALUE' (*note Misc::) if the relation -holds, or zero if it does not, for comparison operators whose results -have a 'MODE_INT' mode, 'FLOAT_STORE_FLAG_VALUE' (*note Misc::) if the -relation holds, or zero if it does not, for comparison operators that -return floating-point values, and a vector of either -'VECTOR_STORE_FLAG_VALUE' (*note 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 'if_then_else'), the mode must be -'VOIDmode'. - - There are two ways that comparison operations may be used. The -comparison operators may be used to compare the condition codes '(cc0)' -against zero, as in '(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 -'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 '(cc0)' were last set to '(compare X Y)', the -comparison operation is identical to '(eq X 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 '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 'gt' and '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 -1 but not -unsigned greater-than, because -1 when regarded as unsigned is actually -'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. - -'(eq:M X Y)' - 'STORE_FLAG_VALUE' if the values represented by X and Y are equal, - otherwise 0. - -'(ne:M X Y)' - 'STORE_FLAG_VALUE' if the values represented by X and Y are not - equal, otherwise 0. - -'(gt:M X Y)' - 'STORE_FLAG_VALUE' if the X is greater than Y. If they are - fixed-point, the comparison is done in a signed sense. - -'(gtu:M X Y)' - Like 'gt' but does unsigned comparison, on fixed-point numbers - only. - -'(lt:M X Y)' -'(ltu:M X Y)' - Like 'gt' and 'gtu' but test for "less than". - -'(ge:M X Y)' -'(geu:M X Y)' - Like 'gt' and 'gtu' but test for "greater than or equal". - -'(le:M X Y)' -'(leu:M X Y)' - Like 'gt' and 'gtu' but test for "less than or equal". - -'(if_then_else COND THEN 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, COND is a comparison expression. This expression - represents a choice, according to COND, between the value - represented by THEN and the one represented by ELSE. - - On most machines, 'if_then_else' expressions are valid only to - express conditional jumps. - -'(cond [TEST1 VALUE1 TEST2 VALUE2 ...] DEFAULT)' - Similar to 'if_then_else', but more general. Each of TEST1, TEST2, - ... is performed in turn. The result of this expression is the - VALUE corresponding to the first nonzero test, or DEFAULT if none - of the tests are nonzero expressions. - - This is currently not valid for instruction patterns and is - supported only for insn attributes. *Note Insn Attributes::. - - -File: gccint.info, Node: Bit-Fields, Next: Vector Operations, Prev: Comparisons, Up: RTL - -13.11 Bit-Fields -================ - -Special expression codes exist to represent bit-field instructions. - -'(sign_extract:M LOC SIZE POS)' - This represents a reference to a sign-extended bit-field contained - or starting in LOC (a memory or register reference). The bit-field - is SIZE bits wide and starts at bit POS. The compilation option - 'BITS_BIG_ENDIAN' says which end of the memory unit POS counts - from. - - If LOC is in memory, its mode must be a single-byte integer mode. - If LOC is in a register, the mode to use is specified by the - operand of the 'insv' or 'extv' pattern (*note Standard Names::) - and is usually a full-word integer mode, which is the default if - none is specified. - - The mode of POS is machine-specific and is also specified in the - 'insv' or 'extv' pattern. - - The mode M is the same as the mode that would be used for LOC if it - were a register. - - A 'sign_extract' can not appear as an lvalue, or part thereof, in - RTL. - -'(zero_extract:M LOC SIZE POS)' - Like '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 '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. - - -File: gccint.info, Node: Vector Operations, Next: Conversions, Prev: Bit-Fields, Up: RTL - -13.12 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. - -'(vec_merge:M VEC1 VEC2 ITEMS)' - This describes a merge operation between two vectors. The result - is a vector of mode M; its elements are selected from either VEC1 - or VEC2. Which elements are selected is described by ITEMS, which - is a bit mask represented by a 'const_int'; a zero bit indicates - the corresponding element in the result vector is taken from VEC2 - while a set bit indicates it is taken from VEC1. - -'(vec_select:M VEC1 SELECTION)' - This describes an operation that selects parts of a vector. VEC1 - is the source vector, and SELECTION is a 'parallel' that contains a - 'const_int' for each of the subparts of the result vector, giving - the number of the source subpart that should be stored into it. - The result mode M is either the submode for a single element of - VEC1 (if only one subpart is selected), or another vector mode with - that element submode (if multiple subparts are selected). - -'(vec_concat:M X1 X2)' - Describes a vector concat operation. The result is a concatenation - of the vectors or scalars X1 and X2; its length is the sum of the - lengths of the two inputs. - -'(vec_duplicate:M X)' - This operation converts a scalar into a vector or 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 or - the scalar modes, and the number of output parts must be an integer - multiple of the number of input parts. - - -File: gccint.info, Node: Conversions, Next: RTL Declarations, Prev: Vector Operations, Up: RTL - -13.13 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 '(plus:SI (reg:QI 34) (reg:SI -80))' because the 'plus' operation requires two operands of the same -machine mode. Therefore, the byte-sized operand is enclosed in a -conversion operation, as in - - (plus:SI (sign_extend:SI (reg:QI 34)) (reg:SI 80)) - - 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, X must not be 'VOIDmode' because the -mode in which to do the conversion would not be known. The conversion -must either be done at compile-time or X must be placed into a register. - -'(sign_extend:M X)' - Represents the result of sign-extending the value X to machine mode - M. M must be a fixed-point mode and X a fixed-point value of a - mode narrower than M. - -'(zero_extend:M X)' - Represents the result of zero-extending the value X to machine mode - M. M must be a fixed-point mode and X a fixed-point value of a - mode narrower than M. - -'(float_extend:M X)' - Represents the result of extending the value X to machine mode M. - M must be a floating point mode and X a floating point value of a - mode narrower than M. - -'(truncate:M X)' - Represents the result of truncating the value X to machine mode M. - M must be a fixed-point mode and X a fixed-point value of a mode - wider than M. - -'(ss_truncate:M X)' - Represents the result of truncating the value X to machine mode M, - using signed saturation in the case of overflow. Both M and the - mode of X must be fixed-point modes. - -'(us_truncate:M X)' - Represents the result of truncating the value X to machine mode M, - using unsigned saturation in the case of overflow. Both M and the - mode of X must be fixed-point modes. - -'(float_truncate:M X)' - Represents the result of truncating the value X to machine mode M. - M must be a floating point mode and X a floating point value of a - mode wider than M. - -'(float:M X)' - Represents the result of converting fixed point value X, regarded - as signed, to floating point mode M. - -'(unsigned_float:M X)' - Represents the result of converting fixed point value X, regarded - as unsigned, to floating point mode M. - -'(fix:M X)' - When M is a floating-point mode, represents the result of - converting floating point value X (valid for mode M) to an integer, - still represented in floating point mode M, by rounding towards - zero. - - When M is a fixed-point mode, represents the result of converting - floating point value X to mode 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. - -'(unsigned_fix:M X)' - Represents the result of converting floating point value X to fixed - point mode M, regarded as unsigned. How rounding is done is not - specified. - -'(fract_convert:M X)' - Represents the result of converting fixed-point value X to - fixed-point mode M, signed integer value X to fixed-point mode M, - floating-point value X to fixed-point mode M, fixed-point value X - to integer mode M regarded as signed, or fixed-point value X to - floating-point mode M. When overflows or underflows happen, the - results are undefined. - -'(sat_fract:M X)' - Represents the result of converting fixed-point value X to - fixed-point mode M, signed integer value X to fixed-point mode M, - or floating-point value X to fixed-point mode M. When overflows or - underflows happen, the results are saturated to the maximum or the - minimum. - -'(unsigned_fract_convert:M X)' - Represents the result of converting fixed-point value X to integer - mode M regarded as unsigned, or unsigned integer value X to - fixed-point mode M. When overflows or underflows happen, the - results are undefined. - -'(unsigned_sat_fract:M X)' - Represents the result of converting unsigned integer value X to - fixed-point mode M. When overflows or underflows happen, the - results are saturated to the maximum or the minimum. - - -File: gccint.info, Node: RTL Declarations, Next: Side Effects, Prev: Conversions, Up: RTL - -13.14 Declarations -================== - -Declaration expression codes do not represent arithmetic operations but -rather state assertions about their operands. - -'(strict_low_part (subreg:M (reg:N R) 0))' - This expression code is used in only one context: as the - destination operand of a 'set' expression. In addition, the - operand of this expression must be a non-paradoxical 'subreg' - expression. - - The presence of 'strict_low_part' says that the part of the - register which is meaningful in mode N, but is not part of mode 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 - M is less than a word. - - -File: gccint.info, Node: Side Effects, Next: Incdec, Prev: RTL Declarations, Up: RTL - -13.15 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. - -'(set LVAL X)' - Represents the action of storing the value of X into the place - represented by LVAL. LVAL must be an expression representing a - place that can be stored in: 'reg' (or 'subreg', 'strict_low_part' - or 'zero_extract'), 'mem', 'pc', 'parallel', or 'cc0'. - - If LVAL is a 'reg', 'subreg' or 'mem', it has a machine mode; then - X must be valid for that mode. - - If LVAL is a '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 - LVAL is a '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 LVAL is a 'strict_low_part' of a subreg, then the part of the - register specified by the machine mode of the 'subreg' is given the - value X and the rest of the register is not changed. - - If LVAL is a 'zero_extract', then the referenced part of the - bit-field (a memory or register reference) specified by the - 'zero_extract' is given the value X and the rest of the bit-field - is not changed. Note that 'sign_extract' can not appear in LVAL. - - If LVAL is '(cc0)', it has no machine mode, and X may be either a - 'compare' expression or a value that may have any mode. The latter - case represents a "test" instruction. The expression '(set (cc0) - (reg:M N))' is equivalent to '(set (cc0) (compare (reg:M N) - (const_int 0)))'. Use the former expression to save space during - the compilation. - - If LVAL is a 'parallel', it is used to represent the case of a - function returning a structure in multiple registers. Each element - of the 'parallel' is an 'expr_list' whose first operand is a 'reg' - and whose second operand is a '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. - - If LVAL is '(pc)', we have a jump instruction, and the - possibilities for X are very limited. It may be a 'label_ref' - expression (unconditional jump). It may be an 'if_then_else' - (conditional jump), in which case either the second or the third - operand must be '(pc)' (for the case which does not jump) and the - other of the two must be a 'label_ref' (for the case which does - jump). X may also be a 'mem' or '(plus:SI (pc) Y)', where Y may be - a 'reg' or a 'mem'; these unusual patterns are used to represent - jumps through branch tables. - - If LVAL is neither '(cc0)' nor '(pc)', the mode of LVAL must not be - 'VOIDmode' and the mode of X must be valid for the mode of LVAL. - - LVAL is customarily accessed with the 'SET_DEST' macro and X with - the 'SET_SRC' macro. - -'(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 'return' expression code is never used. - - Inside an 'if_then_else' expression, represents the value to be - placed in 'pc' to return to the caller. - - Note that an insn pattern of '(return)' is logically equivalent to - '(set (pc) (return))', but the latter form is never used. - -'(simple_return)' - Like '(return)', but truly represents only a function return, while - '(return)' may represent an insn that also performs other functions - of the function epilogue. Like '(return)', this may also occur in - conditional jumps. - -'(call FUNCTION NARGS)' - Represents a function call. FUNCTION is a 'mem' expression whose - address is the address of the function to be called. 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 FUNCTION must have. - The machine description defines macro '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. - -'(clobber X)' - Represents the storing or possible storing of an unpredictable, - undescribed value into X, which must be a 'reg', 'scratch', - 'parallel' or '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 X is '(mem:BLK (const_int 0))' or '(mem:BLK (scratch))', it - means that all memory locations must be presumed clobbered. If X - is a 'parallel', it has the same meaning as a 'parallel' in a '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 - '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 'const'. - - If the last group of expressions in a 'parallel' are each a - 'clobber' expression whose arguments are 'reg' or 'match_scratch' - (*note RTL Template::) expressions, the combiner phase can add the - appropriate '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 'clobber' expression for a register appears inside a - 'parallel' with other side effects, the register allocator - guarantees that the register is unoccupied both before and after - that insn if it is a hard register clobber. For pseudo-register - clobber, the register allocator and the reload pass do not assign - the same hard register to the clobber and the input operands if - there is an insn alternative containing the '&' constraint (*note - Modifiers::) for the clobber and the hard register is in register - classes of the clobber in the alternative. You can clobber either - a specific hard register, a pseudo register, or a '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 - 'scratch' instead of a pseudo-register because this will allow the - combiner phase to add the 'clobber' when required. You do this by - coding ('clobber' ('match_scratch' ...)). 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 - '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. - -'(use X)' - Represents the use of the value of X. It indicates that the value - in 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 X. X must be a 'reg' expression. - - In some situations, it may be tempting to add a 'use' of a register - in a 'parallel' to describe a situation where the value of a - special register will modify the behavior of the instruction. A - 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: - - (parallel [(set (reg:SI 2) (unspec:SI [(reg:SI 3) - (reg:SI 4)] 0)) - (use (reg:SI 1))]) - - 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 'unspec', they will be optimized - away even if register 1 changes in between. - - This means that 'use' can _only_ be used to describe that the - register is live. You should think twice before adding 'use' - statements, more often you will want to use 'unspec' instead. The - '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 'movmemM' or 'call' patterns. - - During the reload phase, an insn that has a 'use' as pattern can - carry a reg_equal note. These 'use' insns will be deleted before - the reload phase exits. - - During the delayed branch scheduling phase, X may be an insn. This - indicates that X previously was located at this place in the code - and its data dependencies need to be taken into account. These - 'use' insns will be deleted before the delayed branch scheduling - phase exits. - -'(parallel [X0 X1 ...])' - Represents several side effects performed in parallel. The square - brackets stand for a vector; the operand of 'parallel' is a vector - of expressions. X0, X1 and so on are individual side effect - expressions--expressions of code 'set', 'call', 'return', - 'simple_return', 'clobber' or '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, - - (parallel [(set (reg:SI 1) (mem:SI (reg:SI 1))) - (set (mem:SI (reg:SI 1)) (reg:SI 1))]) - - says unambiguously that the values of hard register 1 and the - memory location addressed by it are interchanged. In both places - where '(reg:SI 1)' appears as a memory address it refers to the - value in register 1 _before_ the execution of the insn. - - It follows that it is _incorrect_ to use 'parallel' and expect the - result of one 'set' to be available for the next one. For example, - people sometimes attempt to represent a jump-if-zero instruction - this way: - - (parallel [(set (cc0) (reg:SI 34)) - (set (pc) (if_then_else - (eq (cc0) (const_int 0)) - (label_ref ...) - (pc)))]) - - But this is incorrect, because it says that the jump condition - depends on the condition code value _before_ this instruction, not - on the new value that is set by this instruction. - - Peephole optimization, which takes place together with final - assembly code output, can produce insns whose patterns consist of a - 'parallel' whose elements are the operands needed to output the - resulting assembler code--often 'reg', '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 - 'NOTICE_UPDATE_CC', if any, must deal with such insns if you define - any peephole optimizations. - -'(cond_exec [COND EXPR])' - Represents a conditionally executed expression. The EXPR is - executed only if the COND is nonzero. The COND expression must not - have side-effects, but the EXPR may very well have side-effects. - -'(sequence [INSNS ...])' - Represents a sequence of insns. If a 'sequence' appears in the - chain of insns, then each of the INSNS that appears in the sequence - must be suitable for appearing in the chain of insns, i.e. must - satisfy the 'INSN_P' predicate. - - After delay-slot scheduling is completed, an insn and all the insns - that reside in its delay slots are grouped together into a - 'sequence'. The insn requiring the delay slot is the first insn in - the vector; subsequent insns are to be placed in the delay slot. - - '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, - '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. *Note Delay Slots::. - - Some back ends also use 'sequence' objects for purposes other than - delay-slot groups. This is not supported in the common parts of - the compiler, which treat such sequences as delay-slot groups. - - DWARF2 Call Frame Address (CFA) adjustments are sometimes also - expressed using 'sequence' objects as the value of a - 'RTX_FRAME_RELATED_P' note. This only happens if the CFA - adjustments cannot be easily derived from the pattern of the - instruction to which the note is attached. In such cases, the - value of the note is used instead of best-guesing the semantics of - the instruction. The back end can attach notes containing a - 'sequence' of 'set' patterns that express the effect of the parent - instruction. - - 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: - -'(asm_input S)' - Represents literal assembler code as described by the string S. - -'(unspec [OPERANDS ...] INDEX)' -'(unspec_volatile [OPERANDS ...] INDEX)' - Represents a machine-specific operation on OPERANDS. INDEX selects - between multiple machine-specific operations. 'unspec_volatile' is - used for volatile operations and operations that may trap; 'unspec' - is used for other operations. - - These codes may appear inside a 'pattern' of an insn, inside a - 'parallel', or inside an expression. - -'(addr_vec:M [LR0 LR1 ...])' - Represents a table of jump addresses. The vector elements LR0, - etc., are 'label_ref' expressions. The mode M specifies how much - space is given to each address; normally M would be 'Pmode'. - -'(addr_diff_vec:M BASE [LR0 LR1 ...] MIN MAX FLAGS)' - Represents a table of jump addresses expressed as offsets from - BASE. The vector elements LR0, etc., are 'label_ref' expressions - and so is BASE. The mode M specifies how much space is given to - each address-difference. MIN and MAX are set up by branch - shortening and hold a label with a minimum and a maximum address, - respectively. FLAGS indicates the relative position of BASE, MIN - and MAX to the containing insn and of MIN and MAX to BASE. See - rtl.def for details. - -'(prefetch:M ADDR RW LOCALITY)' - Represents prefetch of memory at address ADDR. Operand 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 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. - - -File: gccint.info, Node: Incdec, Next: Assembler, Prev: Side Effects, Up: RTL - -13.16 Embedded Side-Effects on Addresses -======================================== - -Six special side-effect expression codes appear as memory addresses. - -'(pre_dec:M X)' - Represents the side effect of decrementing X by a standard amount - and represents also the value that X has after being decremented. - X must be a 'reg' or 'mem', but most machines allow only a 'reg'. - M must be the machine mode for pointers on the machine in use. The - amount 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: - - (mem:DF (pre_dec:SI (reg:SI 39))) - - This says to decrement pseudo register 39 by the length of a - 'DFmode' value and use the result to address a 'DFmode' value. - -'(pre_inc:M X)' - Similar, but specifies incrementing X instead of decrementing it. - -'(post_dec:M X)' - Represents the same side effect as 'pre_dec' but a different value. - The value represented here is the value X has before being - decremented. - -'(post_inc:M X)' - Similar, but specifies incrementing X instead of decrementing it. - -'(post_modify:M X Y)' - - Represents the side effect of setting X to Y and represents X - before X is modified. X must be a 'reg' or 'mem', but most - machines allow only a 'reg'. M must be the machine mode for - pointers on the machine in use. - - The expression Y must be one of three forms: '(plus:M X Z)', - '(minus:M X Z)', or '(plus:M X I)', where Z is an index register - and I is a constant. - - Here is an example of its use: - - (mem:SF (post_modify:SI (reg:SI 42) (plus (reg:SI 42) - (reg:SI 48)))) - - 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. - -'(pre_modify:M X EXPR)' - Similar except side effects happen before the use. - - These embedded side effect expressions must be used with care. -Instruction patterns may not use them. Until the 'flow' pass of the -compiler, they may occur only to represent pushes onto the stack. The -'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 'parallel' containing an additional -'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. - - -File: gccint.info, Node: Assembler, Next: Debug Information, Prev: Incdec, Up: RTL - -13.17 Assembler Instructions as Expressions -=========================================== - -The RTX code 'asm_operands' represents a value produced by a -user-specified assembler instruction. It is used to represent an 'asm' -statement with arguments. An 'asm' statement with a single output -operand, like this: - - asm ("foo %1,%2,%0" : "=a" (outputvar) : "g" (x + y), "di" (*z)); - -is represented using a single 'asm_operands' RTX which represents the -value that is stored in 'outputvar': - - (set RTX-FOR-OUTPUTVAR - (asm_operands "foo %1,%2,%0" "a" 0 - [RTX-FOR-ADDITION-RESULT RTX-FOR-*Z] - [(asm_input:M1 "g") - (asm_input:M2 "di")])) - -Here the operands of the '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 M1 -is the mode of the sum 'x+y'; M2 is that of '*z'. - - When an 'asm' statement has multiple output values, its insn has -several such 'set' RTX's inside of a 'parallel'. Each 'set' contains an -'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, ... for successive output operands. - - -File: gccint.info, Node: Debug Information, Next: Insns, Prev: Assembler, Up: RTL - -13.18 Variable Location Debug Information in RTL -================================================ - -Variable tracking relies on 'MEM_EXPR' and 'REG_EXPR' annotations to -determine what user variables memory and register references refer to. - - Variable tracking at assignments uses these notes only when they refer -to variables that live at fixed locations (e.g., addressable variables, -global non-automatic variables). For variables whose location may vary, -it relies on the following types of notes. - -'(var_location:MODE VAR EXP STAT)' - Binds variable 'var', a tree, to value EXP, an RTL expression. It - appears only in 'NOTE_INSN_VAR_LOCATION' and 'DEBUG_INSN's, with - slightly different meanings. MODE, if present, represents the mode - of EXP, which is useful if it is a modeless expression. STAT is - only meaningful in notes, indicating whether the variable is known - to be initialized or uninitialized. - -'(debug_expr:MODE DECL)' - Stands for the value bound to the 'DEBUG_EXPR_DECL' DECL, that - points back to it, within value expressions in 'VAR_LOCATION' - nodes. - - -File: gccint.info, Node: Insns, Next: Calls, Prev: Debug Information, Up: RTL - -13.19 Insns -=========== - -The RTL representation of the code for a function is a doubly-linked -chain of objects called "insns". Insns are expressions with special -codes that are used for no other purpose. Some insns are actual -instructions; others represent dispatch tables for '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 -'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 'XEXP' -and 'XINT', but instead three special macros are always used: - -'INSN_UID (I)' - Accesses the unique id of insn I. - -'PREV_INSN (I)' - Accesses the chain pointer to the insn preceding I. If I is the - first insn, this is a null pointer. - -'NEXT_INSN (I)' - Accesses the chain pointer to the insn following I. If I is the - last insn, this is a null pointer. - - The first insn in the chain is obtained by calling 'get_insns'; the -last insn is the result of calling 'get_last_insn'. Within the chain -delimited by these insns, the 'NEXT_INSN' and 'PREV_INSN' pointers must -always correspond: if INSN is not the first insn, - - NEXT_INSN (PREV_INSN (INSN)) == INSN - -is always true and if INSN is not the last insn, - - PREV_INSN (NEXT_INSN (INSN)) == INSN - -is always true. - - After delay slot scheduling, some of the insns in the chain might be -'sequence' expressions, which contain a vector of insns. The value of -'NEXT_INSN' in all but the last of these insns is the next insn in the -vector; the value of 'NEXT_INSN' of the last insn in the vector is the -same as the value of 'NEXT_INSN' for the 'sequence' in which it is -contained. Similar rules apply for 'PREV_INSN'. - - This means that the above invariants are not necessarily true for insns -inside 'sequence' expressions. Specifically, if INSN is the first insn -in a 'sequence', 'NEXT_INSN (PREV_INSN (INSN))' is the insn containing -the 'sequence' expression, as is the value of 'PREV_INSN (NEXT_INSN -(INSN))' if INSN is the last insn in the 'sequence' expression. You can -use these expressions to find the containing 'sequence' expression. - - Every insn has one of the following expression codes: - -'insn' - The expression code 'insn' is used for instructions that do not - jump and do not do function calls. 'sequence' expressions are - always contained in insns with code 'insn' even if one of those - insns should jump or do function calls. - - Insns with code 'insn' have four additional fields beyond the three - mandatory ones listed above. These four are described in a table - below. - -'jump_insn' - The expression code 'jump_insn' is used for instructions that may - jump (or, more generally, may contain 'label_ref' expressions to - which 'pc' can be set in that instruction). If there is an - instruction to return from the current function, it is recorded as - a 'jump_insn'. - - 'jump_insn' insns have the same extra fields as 'insn' insns, - accessed in the same way and in addition contain a field - 'JUMP_LABEL' which is defined once jump optimization has completed. - - For simple conditional and unconditional jumps, this field contains - the 'code_label' to which this insn will (possibly conditionally) - branch. In a more complex jump, 'JUMP_LABEL' records one of the - labels that the insn refers to; other jump target labels are - recorded as 'REG_LABEL_TARGET' notes. The exception is 'addr_vec' - and 'addr_diff_vec', where 'JUMP_LABEL' is 'NULL_RTX' and the only - way to find the labels is to scan the entire body of the insn. - - Return insns count as jumps, but since they do not refer to any - labels, their 'JUMP_LABEL' is 'NULL_RTX'. - -'call_insn' - The expression 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. - - 'call_insn' insns have the same extra fields as 'insn' insns, - accessed in the same way and in addition contain a field - 'CALL_INSN_FUNCTION_USAGE', which contains a list (chain of - 'expr_list' expressions) containing 'use', 'clobber' and sometimes - 'set' expressions that denote hard registers and 'mem's used or - clobbered by the called function. - - A 'mem' generally points to a stack slot in which arguments passed - to the libcall by reference (*note TARGET_PASS_BY_REFERENCE: - Register Arguments.) are stored. If the argument is caller-copied - (*note TARGET_CALLEE_COPIES: Register Arguments.), the stack slot - will be mentioned in 'clobber' and 'use' entries; if it's - callee-copied, only a 'use' will appear, and the 'mem' may point to - addresses that are not stack slots. - - Registers occurring inside a 'clobber' in this list augment - registers specified in 'CALL_USED_REGISTERS' (*note Register - Basics::). - - If the list contains a 'set' involving two registers, it indicates - that the function returns one of its arguments. Such a 'set' may - look like a no-op if the same register holds the argument and the - return value. - -'code_label' - A '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_LABEL_NUMBER' is used to hold the - "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 'LN' where N is - the label number. - - When a 'code_label' appears in an RTL expression, it normally - appears within a 'label_ref' which represents the address of the - label, as a number. - - Besides as a 'code_label', a label can also be represented as a - 'note' of type 'NOTE_INSN_DELETED_LABEL'. - - The field '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. - - The field 'LABEL_KIND' differentiates four different types of - labels: 'LABEL_NORMAL', 'LABEL_STATIC_ENTRY', 'LABEL_GLOBAL_ENTRY', - and 'LABEL_WEAK_ENTRY'. The only labels that do not have type - 'LABEL_NORMAL' are "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 'LABEL_ALT_ENTRY_P' is - provided. It is equivalent to testing whether '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 - 'output_alternate_entry_point', in 'final.c'. - - To set the kind of a label, use the 'SET_LABEL_KIND' macro. - -'jump_table_data' - A 'jump_table_data' insn is a placeholder for the jump-table data - of a 'casesi' or 'tablejump' insn. They are placed after a - 'tablejump_p' insn. A 'jump_table_data' insn is not part o a basic - blockm but it is associated with the basic block that ends with the - 'tablejump_p' insn. The 'PATTERN' of a 'jump_table_data' is always - either an 'addr_vec' or an 'addr_diff_vec', and a 'jump_table_data' - insn is always preceded by a 'code_label'. The 'tablejump_p' insn - refers to that 'code_label' via its 'JUMP_LABEL'. - -'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 'volatile' functions, which do not return (e.g., 'exit'). - They contain no information beyond the three standard fields. - -'note' - 'note' insns are used to represent additional debugging and - declarative information. They contain two nonstandard fields, an - integer which is accessed with the macro 'NOTE_LINE_NUMBER' and a - string accessed with 'NOTE_SOURCE_FILE'. - - If 'NOTE_LINE_NUMBER' is positive, the note represents the position - of a source line and '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, 'NOTE_LINE_NUMBER' is not really a line number but a - code with one of the following values (and 'NOTE_SOURCE_FILE' must - contain a null pointer): - - 'NOTE_INSN_DELETED' - Such a note is completely ignorable. Some passes of the - compiler delete insns by altering them into notes of this - kind. - - 'NOTE_INSN_DELETED_LABEL' - This marks what used to be a 'code_label', but was not used - for other purposes than taking its address and was transformed - to mark that no code jumps to it. - - 'NOTE_INSN_BLOCK_BEG' - '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. - - 'NOTE_INSN_EH_REGION_BEG' - '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. - 'NOTE_EH_HANDLER' identifies which region is associated with - these notes. - - 'NOTE_INSN_FUNCTION_BEG' - Appears at the start of the function body, after the function - prologue. - - 'NOTE_INSN_VAR_LOCATION' - This note is used to generate variable location debugging - information. It indicates that the user variable in its - 'VAR_LOCATION' operand is at the location given in the RTL - expression, or holds a value that can be computed by - evaluating the RTL expression from that static point in the - program up to the next such note for the same user variable. - - These codes are printed symbolically when they appear in debugging - dumps. - -'debug_insn' - The expression code 'debug_insn' is used for pseudo-instructions - that hold debugging information for variable tracking at - assignments (see '-fvar-tracking-assignments' option). They are - the RTL representation of 'GIMPLE_DEBUG' statements (*note - 'GIMPLE_DEBUG'::), with a 'VAR_LOCATION' operand that binds a user - variable tree to an RTL representation of the 'value' in the - corresponding statement. A 'DEBUG_EXPR' in it stands for the value - bound to the corresponding 'DEBUG_EXPR_DECL'. - - Throughout optimization passes, binding information is kept in - pseudo-instruction form, so that, unlike notes, it gets the same - treatment and adjustments that regular instructions would. It is - the variable tracking pass that turns these pseudo-instructions - into var location notes, analyzing control flow, value equivalences - and changes to registers and memory referenced in value - expressions, propagating the values of debug temporaries and - determining expressions that can be used to compute the value of - each user variable at as many points (ranges, actually) in the - program as possible. - - Unlike 'NOTE_INSN_VAR_LOCATION', the value expression in an - 'INSN_VAR_LOCATION' denotes a value at that specific point in the - program, rather than an expression that can be evaluated at any - later point before an overriding 'VAR_LOCATION' is encountered. - E.g., if a user variable is bound to a 'REG' and then a subsequent - insn modifies the 'REG', the note location would keep mapping the - user variable to the register across the insn, whereas the insn - location would keep the variable bound to the value, so that the - variable tracking pass would emit another location note for the - variable at the point in which the register is modified. - - The machine mode of an insn is normally 'VOIDmode', but some phases use -the mode for various purposes. - - The common subexpression elimination pass sets the mode of an insn to -'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 '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 'insn', 'jump_insn' and -'call_insn' insns: - -'PATTERN (I)' - An expression for the side effect performed by this insn. This - must be one of the following codes: 'set', 'call', 'use', - 'clobber', 'return', 'simple_return', 'asm_input', 'asm_output', - 'addr_vec', 'addr_diff_vec', 'trap_if', 'unspec', - 'unspec_volatile', 'parallel', 'cond_exec', or 'sequence'. If it - is a 'parallel', each element of the 'parallel' must be one these - codes, except that 'parallel' expressions cannot be nested and - 'addr_vec' and 'addr_diff_vec' are not permitted inside a - 'parallel' expression. - -'INSN_CODE (I)' - An integer that says which pattern in the machine description - matches this insn, or -1 if the matching has not yet been - attempted. - - Such matching is never attempted and this field remains -1 on an - insn whose pattern consists of a single 'use', 'clobber', - 'asm_input', 'addr_vec' or 'addr_diff_vec' expression. - - Matching is also never attempted on insns that result from an 'asm' - statement. These contain at least one 'asm_operands' expression. - The function '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 'md' - file as some small positive or negative offset from a named - pattern. - -'LOG_LINKS (I)' - A list (chain of '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. These are - only used by the schedulers and by combine. This is a deprecated - data structure. Def-use and use-def chains are now preferred. - -'REG_NOTES (I)' - A list (chain of 'expr_list', 'insn_list' and 'int_list' - expressions) giving miscellaneous information about the insn. It - is often information pertaining to the registers used in this insn. - - The 'LOG_LINKS' field of an insn is a chain of 'insn_list' expressions. -Each of these has two operands: the first is an insn, and the second is -another 'insn_list' expression (the next one in the chain). The last -'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 '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 'REG_NOTES' field of an insn is a chain similar to the 'LOG_LINKS' -field but it includes 'expr_list' and 'int_list' expressions in addition -to '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 'enum reg_note'. The first operand OP of -the note is data whose meaning depends on the kind of note. - - The macro 'REG_NOTE_KIND (X)' returns the kind of register note. Its -counterpart, the macro 'PUT_REG_NOTE_KIND (X, NEWKIND)' sets the -register note type of X to be 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 'LOG_LINKS'. - - These register notes annotate inputs to an insn: - -'REG_DEAD' - The value in 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 OP has no useful value after - this insn since OP is not necessarily modified by this insn. - Rather, no subsequent instruction uses the contents of OP. - -'REG_UNUSED' - The register OP being set by this insn will not be used in a - subsequent insn. This differs from a '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. - -'REG_INC' - The register 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 'post_inc', 'pre_inc', 'post_dec' or - 'pre_dec' expression. - -'REG_NONNEG' - The register 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 'REG_NONNEG' note is added to insns only if the machine - description has a 'decrement_and_branch_until_zero' pattern. - -'REG_LABEL_OPERAND' - This insn uses OP, a 'code_label' or a 'note' of type - 'NOTE_INSN_DELETED_LABEL', but is not a 'jump_insn', or it is a - 'jump_insn' that refers to the operand as an ordinary operand. The - label may still eventually be a jump target, but if so in an - indirect jump in a subsequent insn. The presence of this note - allows jump optimization to be aware that OP is, in fact, being - used, and flow optimization to build an accurate flow graph. - -'REG_LABEL_TARGET' - This insn is a 'jump_insn' but not an 'addr_vec' or - 'addr_diff_vec'. It uses OP, a 'code_label' as a direct or - indirect jump target. Its purpose is similar to that of - 'REG_LABEL_OPERAND'. This note is only present if the insn has - multiple targets; the last label in the insn (in the highest - numbered insn-field) goes into the 'JUMP_LABEL' field and does not - have a 'REG_LABEL_TARGET' note. *Note JUMP_LABEL: Insns. - -'REG_CROSSING_JUMP' - This insn is a 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 - 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. - -'REG_SETJMP' - Appears attached to each 'CALL_INSN' to 'setjmp' or a related - function. - - The following notes describe attributes of outputs of an insn: - -'REG_EQUIV' -'REG_EQUAL' - This note is only valid on an insn that sets only one register and - indicates that that register will be equal to 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 OP, but they will be equal at run time. If the - output of the single 'set' is a 'strict_low_part' expression, the - note refers to the register that is contained in 'SUBREG_REG' of - the 'subreg' expression. - - For 'REG_EQUIV', the register is equivalent to OP throughout the - entire function, and could validly be replaced in all its - occurrences by 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 '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 'REG_PARM_STACK_SPACE' in *note Stack Arguments::. - - In the case of 'REG_EQUAL', the register that is set by this insn - will be equal to OP at run time at the end of this insn but not - necessarily elsewhere in the function. In this case, 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. - '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. 'REG_EQUIV' notes are used by - register allocation to indicate that there is an available - substitute expression (either a constant or a '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 - '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 'REG_EQUAL' note. In the early stages of register - allocation, a 'REG_EQUAL' note is changed into a 'REG_EQUIV' note - if 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 'REG_EQUAL' notes and passes subsequent to register allocation - need only check for 'REG_EQUIV' notes. - - 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. - -'REG_CC_SETTER' -'REG_CC_USER' - On machines that use 'cc0', the insns which set and use 'cc0' set - and use 'cc0' are adjacent. However, when branch delay slot - filling is done, this may no longer be true. In this case a - 'REG_CC_USER' note will be placed on the insn setting 'cc0' to - point to the insn using 'cc0' and a 'REG_CC_SETTER' note will be - placed on the insn using 'cc0' to point to the insn setting 'cc0'. - - These values are only used in the '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 'VOIDmode', and are printed without any -descriptive text. - -'REG_DEP_TRUE' - This indicates a true dependence (a read after write dependence). - -'REG_DEP_OUTPUT' - This indicates an output dependence (a write after write - dependence). - -'REG_DEP_ANTI' - This indicates an anti dependence (a write after read dependence). - - These notes describe information gathered from gcov profile data. They -are stored in the 'REG_NOTES' field of an insn. - -'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 note is represented - as an 'int_list' expression whose integer value is between 0 and - REG_BR_PROB_BASE. Larger values indicate a higher probability that - the branch will be taken. - -'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. - -'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. - - For convenience, the machine mode in an 'insn_list' or 'expr_list' is -printed using these symbolic codes in debugging dumps. - - The only difference between the expression codes 'insn_list' and -'expr_list' is that the first operand of an '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 'expr_list' is printed in the ordinary way as an -expression. - - -File: gccint.info, Node: Calls, Next: Sharing, Prev: Insns, Up: RTL - -13.20 RTL Representation of Function-Call Insns -=============================================== - -Insns that call subroutines have the RTL expression code 'call_insn'. -These insns must satisfy special rules, and their bodies must use a -special RTL expression code, 'call'. - - A 'call' expression has two operands, as follows: - - (call (mem:FM ADDR) NBYTES) - -Here NBYTES is an operand that represents the number of bytes of -argument data being passed to the subroutine, FM is a machine mode -(which must equal as the definition of the 'FUNCTION_MODE' macro in the -machine description) and ADDR represents the address of the subroutine. - - For a subroutine that returns no value, the 'call' expression as shown -above is the entire body of the insn, except that the insn might also -contain 'use' or 'clobber' expressions. - - For a subroutine that returns a value whose mode is not 'BLKmode', the -value is returned in a hard register. If this register's number is R, -then the body of the call insn looks like this: - - (set (reg:M R) - (call (mem:FM ADDR) NBYTES)) - -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 '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. 'call_insn' insns on these -machines should have a body which is a 'parallel' that contains both the -'call' expression and '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 'use' subexpression should mention that -register. - - Functions that are called are assumed to modify all registers listed in -the configuration macro 'CALL_USED_REGISTERS' (*note Register Basics::) -and, with the exception of 'const' functions and library calls, to -modify all of memory. - - Insns containing just 'use' expressions directly precede the -'call_insn' insn to indicate which registers contain inputs to the -function. Similarly, if registers other than those in -'CALL_USED_REGISTERS' are clobbered by the called function, insns -containing a single 'clobber' follow immediately after the call to -indicate which registers. - - -File: gccint.info, Node: Sharing, Next: Reading RTL, Prev: Calls, Up: RTL - -13.21 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. - - * Each pseudo-register has only a single 'reg' object to represent - it, and therefore only a single machine mode. - - * For any symbolic label, there is only one 'symbol_ref' object - referring to it. - - * All 'const_int' expressions with equal values are shared. - - * There is only one 'pc' expression. - - * There is only one 'cc0' expression. - - * There is only one 'const_double' expression with value 0 for each - floating point mode. Likewise for values 1 and 2. - - * There is only one 'const_vector' expression with value 0 for each - vector mode, be it an integer or a double constant vector. - - * No 'label_ref' or '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 'label_ref' - or 'scratch' is seen it is distinct from all others that are seen. - - * Only one '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. - - * When a single 'asm' statement has multiple output operands, a - distinct '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 - 'asm_operands' expressions come from the same statement, so all - optimizations must carefully preserve the sharing if they copy the - vector at all. - - * 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. - - * 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 'unshare_all_rtl' in - 'emit-rtl.c', after which the above rules are guaranteed to be - followed. - - * 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 - 'copy_rtx_if_shared', which is a subroutine of 'unshare_all_rtl'. - - -File: gccint.info, Node: Reading RTL, Prev: Sharing, Up: RTL - -13.22 Reading RTL -================= - -To read an RTL object from a file, call 'read_rtx'. It takes one -argument, a stdio stream, and returns a single RTL object. This routine -is defined in '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 'tree.h' and 'tree.def'. -The documentation for this structure (*note GENERIC::) is incomplete. - - -File: gccint.info, Node: Control Flow, Next: Loop Analysis and Representation, Prev: RTL, Up: Top - -14 Control Flow Graph -********************* - -A control flow graph (CFG) is a data structure built on top of the -intermediate code representation (the RTL or 'GIMPLE' 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 'basic-block.h'. - - In GCC, the representation of control flow is maintained throughout the -compilation process, from constructing the CFG early in 'pass_build_cfg' -to 'pass_free_cfg' (see 'passes.def'). The CFG takes various different -modes and may undergo extensive manipulations, but the graph is always -valid between its construction and its release. This way, transfer of -information such as data flow, a measured profile, or the loop tree, can -be propagated through the passes pipeline, and even from 'GIMPLE' to -'RTL'. - - Often the CFG may be better viewed as integral part of instruction -chain, than structure built on the top of it. Updating the compiler's -intermediate representation for instructions can not be easily done -without proper maintenance of the CFG simultaneously. - -* 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. - - -File: gccint.info, Node: Basic Blocks, Next: Edges, Up: Control Flow - -14.1 Basic Blocks -================= - -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 -'basic_block' data type. - - Special basic blocks represent possible entry and exit points of a -function. These blocks are called 'ENTRY_BLOCK_PTR' and -'EXIT_BLOCK_PTR'. These blocks do not contain any code. - - The 'BASIC_BLOCK' array contains all basic blocks in an unspecified -order. Each 'basic_block' structure has a field that holds a unique -integer identifier 'index' that is the index of the block in the -'BASIC_BLOCK' array. The total number of basic blocks in the function -is '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 'last_basic_block'. The indices 0 -and 1 are special codes reserved for 'ENTRY_BLOCK' and 'EXIT_BLOCK', the -indices of 'ENTRY_BLOCK_PTR' and 'EXIT_BLOCK_PTR'. - - Two pointer members of the 'basic_block' structure are the pointers -'next_bb' and '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 'FOR_EACH_BB' can be used to visit -all the basic blocks in lexicographical order, except 'ENTRY_BLOCK' and -'EXIT_BLOCK'. The macro 'FOR_ALL_BB' also visits all basic blocks in -lexicographical order, including 'ENTRY_BLOCK' and 'EXIT_BLOCK'. - - The functions 'post_order_compute' and 'inverted_post_order_compute' -can be used to compute topological orders of the CFG. The orders are -stored as vectors of basic block indices. The 'BASIC_BLOCK' array can -be used to iterate each basic block by index. Dominator traversals are -also possible using 'walk_dominator_tree'. Given two basic blocks A and -B, block A dominates block B if A is _always_ executed before B. - - Each 'basic_block' also contains pointers to the first instruction (the -"head") and the last instruction (the "tail") or "end" of the -instruction stream contained in a basic block. In fact, since the -'basic_block' data type is used to represent blocks in both major -intermediate representations of GCC ('GIMPLE' and RTL), there are -pointers to the head and end of a basic block for both representations, -stored in intermediate representation specific data in the 'il' field of -'struct basic_block_def'. - - For RTL, these pointers are 'BB_HEAD' and 'BB_END'. - - In the RTL representation of a function, the instruction stream -contains not only the "real" instructions, but also "notes" or "insn -notes" (to distinguish them from "reg 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, so updating can sometimes be tedious. All types of -insn notes are defined in 'insn-notes.def'. - - In the RTL function representation, the instructions contained in a -basic block always follow a 'NOTE_INSN_BASIC_BLOCK', but zero or more -'CODE_LABEL' nodes can precede the block note. A basic block ends with -a control flow instruction or with the last instruction before the next -'CODE_LABEL' or 'NOTE_INSN_BASIC_BLOCK'. By definition, a 'CODE_LABEL' -cannot appear in the middle of the instruction stream of a basic block. - - 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 "fall-thru", the existence of such construct in the way needs to be -checked by calling 'can_fallthru' function. - - For the 'GIMPLE' representation, the PHI nodes and statements contained -in a basic block are in a 'gimple_seq' pointed to by the basic block -intermediate language specific pointers. Abstract containers and -iterators are used to access the PHI nodes and statements in a basic -blocks. These iterators are called "GIMPLE statement iterators" (GSIs). -Grep for '^gsi' in the various 'gimple-*' and 'tree-*' files. The -following snippet will pretty-print all PHI nodes the statements of the -current function in the GIMPLE representation. - - basic_block bb; - - FOR_EACH_BB (bb) - { - gimple_stmt_iterator si; - - for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) - { - gimple phi = gsi_stmt (si); - print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); - } - for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) - { - gimple stmt = gsi_stmt (si); - print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); - } - } - - -File: gccint.info, Node: Edges, Next: Profile information, Prev: Basic Blocks, Up: Control Flow - -14.2 Edges -========== - -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 'edge' data type. Each 'edge' acts as a link between two -basic blocks: The 'src' member of an edge points to the predecessor -basic block of the 'dest' basic block. The members 'preds' and 'succs' -of the 'basic_block' data type point to type-safe vectors of edges to -the predecessors and successors of the block. - - When walking the edges in an edge vector, "edge iterators" should be -used. Edge iterators are constructed using the 'edge_iterator' data -structure and several methods are available to operate on them: - -'ei_start' - This function initializes an 'edge_iterator' that points to the - first edge in a vector of edges. - -'ei_last' - This function initializes an 'edge_iterator' that points to the - last edge in a vector of edges. - -'ei_end_p' - This predicate is 'true' if an 'edge_iterator' represents the last - edge in an edge vector. - -'ei_one_before_end_p' - This predicate is 'true' if an 'edge_iterator' represents the - second last edge in an edge vector. - -'ei_next' - This function takes a pointer to an 'edge_iterator' and makes it - point to the next edge in the sequence. - -'ei_prev' - This function takes a pointer to an 'edge_iterator' and makes it - point to the previous edge in the sequence. - -'ei_edge' - This function returns the 'edge' currently pointed to by an - 'edge_iterator'. - -'ei_safe_safe' - This function returns the 'edge' currently pointed to by an - 'edge_iterator', but returns '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 'NULL' edge indicates the - end of the sequence. - - The convenience macro '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: - - edge e; - edge_iterator ei; - - FOR_EACH_EDGE (e, ei, bb->succs) - { - if (e->flags & EDGE_FALLTHRU) - break; - } - - There are various reasons why control flow may transfer from one block -to another. One possibility is that some instruction, for example a -'CODE_LABEL', in a linearized instruction stream just always starts a -new basic block. In this case a "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 'flags' field of the '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: - -_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. - -_fall-thru_ - Fall-thru edges are present in case where the basic block may - continue execution to the following one without branching. These - edges have the '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 - '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. - -_exception handling_ - 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 and Ada, 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 'EDGE_ABNORMAL' and 'EDGE_EH' flags set. - - 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 - 'purge_dead_edges' call. - - In the RTL representation, the destination of an exception edge is - specified by 'REG_EH_REGION' note attached to the insn. In case of - a trapping call the 'EDGE_ABNORMAL_CALL' flag is set too. In the - 'GIMPLE' representation, this extra flag is not set. - - In the RTL representation, the predicate 'may_trap_p' may be used - to check whether instruction still may trap or not. For the tree - representation, the 'tree_could_trap_p' predicate is available, but - this predicate only checks for possible memory traps, as in - dereferencing an invalid pointer location. - -_sibling calls_ - Sibling calls or tail calls terminate the function in a - non-standard way and thus an edge to the exit must be present. - 'EDGE_SIBCALL' and 'EDGE_ABNORMAL' are set in such case. These - edges only exist in the RTL representation. - -_computed jumps_ - Computed jumps contain edges to all labels in the function - referenced from the code. All those edges have '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 _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, - - goto *x; - [ ... ] - - goto *x; - [ ... ] - - goto *x; - [ ... ] - - factoring the computed jumps results in the following code sequence - which has a much simpler flow graph: - - goto y; - [ ... ] - - goto y; - [ ... ] - - goto y; - [ ... ] - - y: - goto *x; - - 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 (in the pass called - 'pass_duplicate_computed_gotos'). 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. - -_nonlocal goto handlers_ - GCC allows nested functions to return into caller using a '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 - 'EDGE_ABNORMAL' and 'EDGE_ABNORMAL_CALL' flags set. - -_function entry points_ - By definition, execution of function starts at basic block 0, so - there is always an edge from the 'ENTRY_BLOCK_PTR' to basic block - 0. There is no 'GIMPLE' representation for alternate entry points - at this moment. In RTL, alternate entry points are specified by - 'CODE_LABEL' with '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. - -_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. - - -File: gccint.info, Node: Profile information, Next: Maintaining the CFG, Prev: Edges, Up: Control Flow - -14.3 Profile information -======================== - -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 "profile feedback", but it can also estimate branch -probabilities based on statics and heuristics. - - 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. - - 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 'predict.def' for details) and compute estimated -frequencies of each basic block by propagating the probabilities over -the graph. - - Each 'basic_block' contains two integer fields to represent profile -information: 'frequency' and 'count'. The '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 'BB_FREQ_BASE'. The most -frequently executed basic block in function is initially set to -'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. - - The '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 '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. - - Each edge also contains a branch probability field: an integer in the -range from 0 to 'REG_BR_PROB_BASE'. It represents probability of -passing control from the end of the 'src' basic block to the 'dest' -basic block, i.e. the probability that control will flow along this -edge. The 'EDGE_FREQUENCY' macro is available to compute how frequently -a given edge is taken. There is a '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 'REG_BR_PROB' macro) since -they are used when instructions are output to the assembly file and the -flow graph is no longer maintained. - - The probability that control flow arrives via a given edge to its -destination basic block is called "reverse probability" and is not -directly represented, but it may be easily computed from frequencies of -basic blocks. - - 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 -'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. - - It is important to point out that 'REG_BR_PROB_BASE' and '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 'count' field, as modern CPUs are fast enough to execute -$2^32$ operations quickly. - - -File: gccint.info, Node: Maintaining the CFG, Next: Liveness information, Prev: Profile information, Up: Control Flow - -14.4 Maintaining the CFG -======================== - -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 -'basic_block' and '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 "hooks" is defined so that each -representation can provide its own implementation of CFG manipulation -routines when necessary. These hooks are defined in '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 'GIMPLE' 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). - - In the RTL representation, each instruction has a 'BLOCK_FOR_INSN' -value that represents pointer to the basic block that contains the -instruction. In the 'GIMPLE' representation, the function 'gimple_bb' -returns a pointer to the basic block containing the queried statement. - - When changes need to be applied to a function in its 'GIMPLE' -representation, "GIMPLE statement iterators" should be used. These -iterators provide an integrated abstraction of the flow graph and the -instruction stream. Block statement iterators are constructed using the -'gimple_stmt_iterator' data structure and several modifier are -available, including the following: - -'gsi_start' - This function initializes a 'gimple_stmt_iterator' that points to - the first non-empty statement in a basic block. - -'gsi_last' - This function initializes a 'gimple_stmt_iterator' that points to - the last statement in a basic block. - -'gsi_end_p' - This predicate is 'true' if a 'gimple_stmt_iterator' represents the - end of a basic block. - -'gsi_next' - This function takes a 'gimple_stmt_iterator' and makes it point to - its successor. - -'gsi_prev' - This function takes a 'gimple_stmt_iterator' and makes it point to - its predecessor. - -'gsi_insert_after' - This function inserts a statement after the 'gimple_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. - -'gsi_insert_before' - This function inserts a statement before the 'gimple_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. - -'gsi_remove' - This function removes the 'gimple_stmt_iterator' passed in and - rechains the remaining statements in a basic block, if any. - - In the RTL representation, the macros 'BB_HEAD' and 'BB_END' may be -used to get the head and end 'rtx' of a basic block. No abstract -iterators are defined for traversing the insn chain, but you can just -use 'NEXT_INSN' and 'PREV_INSN' instead. *Note Insns::. - - 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 'purge_dead_edges' on a -given basic block to remove superfluous edges, if any. - - 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 'redirect_edge_and_branch' is preferred over more low level -functions, such as 'redirect_jump' that operate on RTL chain only. The -CFG hooks defined in 'cfghooks.h' should provide the complete API -required for manipulating and maintaining the CFG. - - 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 '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. - - 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 'insert_insn_on_edge' function that -emits an instruction "on the edge", caching it for a later -'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 'GIMPLE' representation, the equivalent functions are -'gsi_insert_on_edge' which inserts a block statement iterator on an -edge, and 'gsi_commit_edge_inserts' which flushes the instruction to -actual instruction stream. - - While debugging the optimization pass, the 'verify_flow_info' function -may be useful to find bugs in the control flow graph updating code. - - -File: gccint.info, Node: Liveness information, Prev: Maintaining the CFG, Up: Control Flow - -14.5 Liveness information -========================= - -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. - - Liveness information is available in the back end starting with -'pass_df_initialize' and ending with 'pass_df_finish'. Three flavors of -live analysis are available: With 'LR', it is possible to determine at -any point 'P' in the function if the register may be used on some path -from 'P' to the end of the function. With 'UR', it is possible to -determine if there is a path from the beginning of the function to 'P' -that defines the variable. 'LIVE' is the intersection of the 'LR' and -'UR' and a variable is live at 'P' if there is both an assignment that -reaches it from the beginning of the function and a use that can be -reached on some path from 'P' to the end of the function. - - In general 'LIVE' is the most useful of the three. The macros -'DF_[LR,UR,LIVE]_[IN,OUT]' can be used to access this information. The -macros take a basic block number and return a bitmap that is indexed by -the register number. This information is only guaranteed to be up to -date after calls are made to 'df_analyze'. See the file 'df-core.c' for -details on using the dataflow. - - 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 'REG_DEAD' notes -representing that the value of a given register is no longer needed, or -'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. - - -File: gccint.info, Node: Loop Analysis and Representation, Next: Machine Desc, Prev: Control Flow, Up: Top - -15 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. -* Omega:: A solver for linear programming problems. - - -File: gccint.info, Node: Loop representation, Next: Loop querying, Up: Loop Analysis and Representation - -15.1 Loop representation -======================== - -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 'cfgloop.h'. Loop -structures are analyzed and this information disposed or updated at the -discretion of individual passes. Still most of the generic CFG -manipulation routines are aware of loop structures and try to keep them -up-to-date. By this means an increasing part of the compilation -pipeline is setup to maintain loop structure across passes to allow -attaching meta information to individual loops for consumption by later -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. -Heuristic based on profile information and structure of the induction -variables in the loops 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. You may avoid CFG changes by passing -'LOOPS_MAY_HAVE_MULTIPLE_LATCHES' flag to the loop discovery, note -however that most other loop manipulation functions will not work -correctly for loops with multiple latch edges (the functions that only -query membership of blocks to loops and subloop relationships, or -enumerate and test loop exits, can be expected to work). - - 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 '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 'struct loop' -structure. Each loop is assigned an index ('num' field of the 'struct -loop' structure), and the pointer to the loop is stored in the -corresponding field of the 'larray' vector in the loops structure. The -indices do not have to be continuous, there may be empty ('NULL') -entries in the 'larray' created by deleting loops. Also, there is no -guarantee on the relative order of a loop and its subloops in the -numbering. The index of a loop never changes. - - The entries of the 'larray' field should not be accessed directly. The -function 'get_loop' returns the loop description for a loop with the -given index. 'number_of_loops' function returns number of loops in the -function. To traverse all loops, use 'FOR_EACH_LOOP' macro. The -'flags' argument of the macro is used to determine the direction of -traversal and the set of loops visited. Each loop is guaranteed to be -visited exactly once, regardless of the changes to the loop tree, and -the loops may be removed during the traversal. The newly created loops -are never traversed, if they need to be visited, this must be done -separately after their creation. The 'FOR_EACH_LOOP' macro allocates -temporary variables. If the 'FOR_EACH_LOOP' loop were ended using break -or goto, they would not be released; 'FOR_EACH_LOOP_BREAK' macro must be -used instead. - - Each basic block contains the reference to the innermost loop it -belongs to ('loop_father'). For this reason, it is only possible to -have one 'struct loops' structure initialized at the same time for each -CFG. The global variable 'current_loops' contains the 'struct loops' -structure. Many of the loop manipulation functions assume that -dominance information is up-to-date. - - The loops are analyzed through '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: - - * 'LOOPS_MAY_HAVE_MULTIPLE_LATCHES': If this flag is set, no changes - to CFG will be performed in the loop analysis, in particular, loops - with multiple latch edges will not be disambiguated. If a loop has - multiple latches, its latch block is set to NULL. Most of the loop - manipulation functions will not work for loops in this shape. No - other flags that require CFG changes can be passed to - loop_optimizer_init. - * '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. - * '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. - * '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 'BB_IRREDUCIBLE_LOOP' - and '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). - * 'LOOPS_HAVE_RECORDED_EXITS': The lists of exits are recorded and - updated for each loop. This makes some functions (e.g., - 'get_loop_exit_edges') more efficient. Some functions (e.g., - 'single_exit') can be used only if the lists of exits are recorded. - - These properties may also be computed/enforced later, using functions -'create_preheaders', 'force_single_succ_latches', -'mark_irreducible_loops' and 'record_loop_exits'. The properties can be -queried using 'loops_state_satisfies_p'. - - The memory occupied by the loops structures should be freed with -'loop_optimizer_finalize' function. When loop structures are setup to -be preserved across passes this function reduces the information to be -kept up-to-date to a minimum (only 'LOOPS_MAY_HAVE_MULTIPLE_LATCHES' -set). - - 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, 'cleanup_tree_cfg_loop' function -can be used to cleanup CFG while updating the loops structures if -'current_loops' is set. - - At the moment loop structure is preserved from the start of GIMPLE loop -optimizations until the end of RTL loop optimizations. During this time -a loop can be tracked by its 'struct loop' and number. - - -File: gccint.info, Node: Loop querying, Next: Loop manipulation, Prev: Loop representation, Up: Loop Analysis and Representation - -15.2 Loop querying -================== - -The functions to query the information about loops are declared in -'cfgloop.h'. Some of the information can be taken directly from the -structures. '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: - - * 'header', 'latch': Header and latch basic blocks of the loop. - * 'num_nodes': Number of basic blocks in the loop (including the - basic blocks of the sub-loops). - * 'depth': The depth of the loop in the loops tree, i.e., the number - of super-loops of the loop. - * 'outer', 'inner', 'next': The super-loop, the first sub-loop, and - the sibling of the loop in the loops tree. - - 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: - - * 'flow_loops_dump': Dumps the information about loops to a file. - * 'verify_loop_structure': Checks consistency of the loop structures. - * 'loop_latch_edge': Returns the latch edge of a loop. - * 'loop_preheader_edge': If loops have preheaders, returns the - preheader edge of a loop. - * 'flow_loop_nested_p': Tests whether loop is a sub-loop of another - loop. - * 'flow_bb_inside_loop_p': Tests whether a basic block belongs to a - loop (including its sub-loops). - * 'find_common_loop': Finds the common super-loop of two loops. - * 'superloop_at_depth': Returns the super-loop of a loop with the - given depth. - * 'tree_num_loop_insns', 'num_loop_insns': Estimates the number of - insns in the loop, on GIMPLE and on RTL. - * 'loop_exit_edge_p': Tests whether edge is an exit from a loop. - * 'mark_loop_exit_edges': Marks all exit edges of all loops with - 'EDGE_LOOP_EXIT' flag. - * 'get_loop_body', 'get_loop_body_in_dom_order', - '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. - * 'single_exit': Returns the single exit edge of the loop, or 'NULL' - if the loop has more than one exit. You can only use this function - if LOOPS_HAVE_MARKED_SINGLE_EXITS property is used. - * 'get_loop_exit_edges': Enumerates the exit edges of a loop. - * '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). - - -File: gccint.info, Node: Loop manipulation, Next: LCSSA, Prev: Loop querying, Up: Loop Analysis and Representation - -15.3 Loop manipulation -====================== - -The loops tree can be manipulated using the following functions: - - * 'flow_loop_tree_node_add': Adds a node to the tree. - * 'flow_loop_tree_node_remove': Removes a node from the tree. - * 'add_bb_to_loop': Adds a basic block to a loop. - * 'remove_bb_from_loops': Removes a basic block from loops. - - Most low-level CFG functions update loops automatically. The following -functions handle some more complicated cases of CFG manipulations: - - * 'remove_path': Removes an edge and all blocks it dominates. - * '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. - - 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: - - * 'create_iv': Creates a new induction variable. Only works on - GIMPLE. 'standard_iv_increment_position' can be used to find a - suitable place for the iv increment. - * 'duplicate_loop_to_header_edge', - '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. 'can_duplicate_loop_p' - ('can_unroll_loop_p' on GIMPLE) must be true for the duplicated - loop. - * 'loop_version', '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). - * '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. - - -File: gccint.info, Node: LCSSA, Next: Scalar evolutions, Prev: Loop manipulation, Up: Loop Analysis and Representation - -15.4 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: - - * 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. - * 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. - * 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). - - 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). -'rewrite_into_loop_closed_ssa' is used to rewrite SSA form to LCSSA, and -'verify_loop_closed_ssa' to check that the invariant of LCSSA is -preserved. - - -File: gccint.info, Node: Scalar evolutions, Next: loop-iv, Prev: LCSSA, Up: Loop Analysis and Representation - -15.5 Scalar evolutions -====================== - -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 -'tree-scalar-evolution.h'. To use scalar evolutions analysis, -'scev_initialize' must be used. To stop using SCEV, '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, 'scev_reset' must be called to clean the caches. - - Given an SSA name, its behavior in loops can be analyzed using the -'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, 'instantiate_parameters' or 'resolve_mixers' functions must -be used. '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. '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 'SCEV_NOT_KNOWN', -used for SSA names whose value cannot be expressed. The other one is -'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 'POLYNOMIAL_CHREC(base, step, loop)' if it is (in -the specified loop) equivalent to 'x_1' in the following example - - while (...) - { - x_1 = phi (base, x_2); - x_2 = x_1 + step; - } - - Note that this includes the language restrictions on the operations. -For example, if we compile C code and '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, -'simple_iv' function may be used to analyze a value - the result is a -loop-invariant base and step. - - -File: gccint.info, Node: loop-iv, Next: Number of iterations, Prev: Scalar evolutions, Up: Loop Analysis and Representation - -15.6 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 'cfgloop.h'. Before analyzing induction variables in a -loop L, 'iv_analysis_loop_init' function must be called on L. After the -analysis (possibly calling 'iv_analysis_loop_init' for several loops) is -finished, 'iv_analysis_done' should be called. The following functions -can be used to access the results of the analysis: - - * '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. - * 'iv_analyze_result': Analyzes result of the assignment in the given - insn. - * 'iv_analyze_expr': Analyzes a more complicated expression. All its - operands are analyzed by 'iv_analyze', and hence they must be used - in the specified insn or one of the following insns. - - The description of the induction variable is provided in 'struct -rtx_iv'. In order to handle subregs, the representation is a bit -complicated; if the value of the 'extend' field is not 'UNKNOWN', the -value of the induction variable in the i-th iteration is - - delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)), - - with the following exception: if 'first_special' is true, then the -value in the first iteration (when 'i' is zero) is 'delta + mult * -base'. However, if 'extend' is equal to 'UNKNOWN', then 'first_special' -must be false, 'delta' 0, 'mult' 1 and the value in the i-th iteration -is - - subreg_{mode} (base + i * step) - - The function 'get_iv_value' can be used to perform these calculations. - - -File: gccint.info, Node: Number of iterations, Next: Dependency analysis, Prev: loop-iv, Up: Loop Analysis and Representation - -15.7 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. The -number of iterations of a loop in GCC is defined as the number of -executions of the loop latch. In many cases, it is not possible to -determine the 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: - - * 'assumptions': If this condition is false, the rest of the - information is invalid. - * 'noloop_assumptions' on RTL, 'may_be_zero' on GIMPLE: If this - condition is true, the loop exits in the first iteration. - * '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 'assumptions'. - * 'niter_expr' on RTL, '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. - - 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 'struct tree_niter_desc' structure. -Number of iterations before the loop is exited through a given exit can -be determined using 'number_of_iterations_exit' function. On RTL, the -results are returned in 'struct niter_desc' structure. The -corresponding function is named '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 - 'find_loop_niter' on -GIMPLE and '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 - -'number_of_latch_executions' on GIMPLE and '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 -'number_of_latch_executions' works only for single-exit loops. The -function 'number_of_cond_exit_executions' can be used to determine -number of executions of the exit condition of a single-exit loop (i.e., -the 'number_of_latch_executions' increased by one). - - -File: gccint.info, Node: Dependency analysis, Next: Omega, Prev: Number of iterations, Up: Loop Analysis and Representation - -15.8 Data Dependency Analysis -============================= - -The code for the data dependence analysis can be found in -'tree-data-ref.c' and its interface and data structures are described in -'tree-data-ref.h'. The function that computes the data dependences for -all the array and pointer references for a given loop is -'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 'n', the vector containing the dependence relations will contain -'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 '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 'data_reference', where 'data_reference_p' is a name of a -pointer to the data reference structure. The structure contains the -following elements: - - * '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 'a.b[i][j]', the base object is 'a.b' and - the access functions, one for each array subscript, are: '{i_init, - + i_step}_1, {j_init, +, j_step}_2'. - - * '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: - - for1 i - for2 j - *((int *)p + i + j) = a[i][j]; - - The access function of the pointer access is '{0, + 4B}_for2' - relative to 'p + i'. The access functions of the array are - '{i_init, + i_step}_for1' and '{j_init, +, j_step}_for2' relative - to '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 'a' and 'b' are represented as arrays, compare 'a.base_object' - and 'b.base_object'; if they are equal, apply dependence tests (use - access functions based on base_objects). Else if both 'a' and 'b' - are represented as pointers, compare 'a.first_location' and - 'b.first_location'; if they are equal, apply dependence tests (use - access functions based on first location). However, if 'a' and 'b' - are represented differently, only try to prove that the bases are - definitely different. - - * Aliasing information. - * Alignment information. - - The structure describing the relation between two data references is -'data_dependence_relation' and the shorter name for a pointer to such a -structure is 'ddr_p'. This structure contains: - - * a pointer to each data reference, - * a tree node 'are_dependent' that is set to 'chrec_known' if the - analysis has proved that there is no dependence between these two - data references, '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 'are_dependent' is - set to 'NULL_TREE' if there exist a dependence relation between the - data references, and the description of this dependence relation is - given in the 'subscripts', 'dir_vects', and 'dist_vects' arrays, - * a boolean that determines whether the dependence relation can be - represented by a classical distance vector, - * an array '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 'A[f1][f2][f3]' and 'B[g1][g2][g3]', there are - three subscripts: '(f1, g1), (f2, g2), (f3, g3)'. - * two arrays 'dir_vects' and 'dist_vects' that contain classical - representations of the data dependences under the form of direction - and distance dependence vectors, - * an array of loops 'loop_nest' that contains the loops to which the - distance and direction vectors refer to. - - Several functions for pretty printing the information extracted by the -data dependence analysis are available: 'dump_ddrs' prints with a -maximum verbosity the details of a data dependence relations array, -'dump_dist_dir_vectors' prints only the classical distance and direction -vectors for a data dependence relations array, and -'dump_data_references' prints the details of the data references -contained in a data reference array. - - -File: gccint.info, Node: Omega, Prev: Dependency analysis, Up: Loop Analysis and Representation - -15.9 Omega a solver for linear programming problems -=================================================== - -The data dependence analysis contains several solvers triggered -sequentially from the less complex ones to the more sophisticated. For -ensuring the consistency of the results of these solvers, a data -dependence check pass has been implemented based on two different -solvers. The second method that has been integrated to GCC is based on -the Omega dependence solver, written in the 1990's by William Pugh and -David Wonnacott. Data dependence tests can be formulated using a subset -of the Presburger arithmetics that can be translated to linear -constraint systems. These linear constraint systems can then be solved -using the Omega solver. - - The Omega solver is using Fourier-Motzkin's algorithm for variable -elimination: a linear constraint system containing 'n' variables is -reduced to a linear constraint system with 'n-1' variables. The Omega -solver can also be used for solving other problems that can be expressed -under the form of a system of linear equalities and inequalities. The -Omega solver is known to have an exponential worst case, also known -under the name of "omega nightmare" in the literature, but in practice, -the omega test is known to be efficient for the common data dependence -tests. - - The interface used by the Omega solver for describing the linear -programming problems is described in 'omega.h', and the solver is -'omega_solve_problem'. - - -File: gccint.info, Node: Machine Desc, Next: Target Macros, Prev: Loop Analysis and Representation, Up: Top - -16 Machine Descriptions -*********************** - -A machine description has two parts: a file of instruction patterns -('.md' file) and a C header file of macro definitions. - - The '.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 '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 'define_insn' patterns for - predication. -* Define Subst:: Generating 'define_insn' and 'define_expand' - patterns from other patterns. -* Constant Definitions::Defining symbolic constants that can be used in the - md file. -* Iterators:: Using iterators to generate patterns from a template. - - -File: gccint.info, Node: Overview, Next: Patterns, Up: Machine Desc - -16.1 Overview of How the Machine Description is Used -==================================================== - -There are three main conversions that happen in the compiler: - - 1. The front end reads the source code and builds a parse tree. - - 2. The parse tree is used to generate an RTL insn list based on named - instruction patterns. - - 3. The insn list is matched against the RTL templates to produce - assembler code. - - For the generate pass, only the names of the insns matter, from either -a named 'define_insn' or a '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 'define_insn' is used, the template given is inserted into the -insn list. If a '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 'emit_insn()', and invoke 'DONE'. -For certain named patterns, it may invoke 'FAIL' to tell the compiler to -use an alternate way of performing that task. If it invokes neither -'DONE' nor 'FAIL', the template given in the pattern is inserted, as if -the 'define_expand' were a '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 -'define_split' and 'define_peephole' patterns get used, for example. - - Finally, the insn list's RTL is matched up with the RTL templates in -the 'define_insn' patterns, and those patterns are used to emit the -final assembly code. For this purpose, each named 'define_insn' acts -like it's unnamed, since the names are ignored. - - -File: gccint.info, Node: Patterns, Next: Example, Prev: Overview, Up: Machine Desc - -16.2 Everything about Instruction Patterns -========================================== - -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 'define_insn' expression. - - A 'define_insn' is an RTL expression containing four or five operands: - - 1. 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 '*' 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. - - 2. The "RTL template" (*note RTL Template::) is a vector of incomplete - RTL expressions which show what the instruction should look like. - It is incomplete because it may contain 'match_operand', - 'match_operator', and '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 'parallel' expression containing - the elements described. - - 3. 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. - - 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. - - 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 '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. - - 4. The "output template": a string that says how to output matching - insns as assembler code. '%' in this string specifies where to - substitute the value of an operand. *Note Output Template::. - - When simple substitution isn't general enough, you can specify a - piece of C code to compute the output. *Note Output Statement::. - - 5. Optionally, a vector containing the values of attributes for insns - matching this pattern. *Note Insn Attributes::. - - -File: gccint.info, Node: Example, Next: RTL Template, Prev: Patterns, Up: Machine Desc - -16.3 Example of 'define_insn' -============================= - -Here is an actual example of an instruction pattern, for the -68000/68020. - - (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\"; - }") - -This can also be written using braced strings: - - (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"; - }) - - 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 'tstsi' means "test a '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. - - '"rm"' is an operand constraint. Its meaning is explained below. - - -File: gccint.info, Node: RTL Template, Next: Output Template, Prev: Example, Up: Machine Desc - -16.4 RTL Template -================= - -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. - -'(match_operand:M N PREDICATE CONSTRAINT)' - This expression is a placeholder for operand number N of the insn. - When constructing an insn, operand number 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 N; but it must - satisfy 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 'match_operand' - expression in the pattern for each operand number. Usually - operands are numbered in the order of appearance in 'match_operand' - expressions. In the case of a 'define_expand', any operand numbers - used only in 'match_dup' expressions have higher values than all - other operand numbers. - - PREDICATE is a string that is the name of a function that accepts - two arguments, an expression and a machine mode. *Note - Predicates::. During matching, the function will be called with - the putative operand as the expression and M as the mode argument - (if M is not specified, 'VOIDmode' will be used, which normally - causes PREDICATE to accept any mode). If it returns zero, this - instruction pattern fails to match. 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, PREDICATE will reject modes other than M--but not - always. For example, the predicate 'address_operand' uses M as the - mode of memory ref that the address should be valid for. Many - predicates accept 'const_int' nodes even though their mode is - 'VOIDmode'. - - CONSTRAINT controls reloading and the choice of the best register - class to use for a value, as explained later (*note 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. - -'(match_scratch:M N CONSTRAINT)' - This expression is also a placeholder for operand number N and - indicates that operand must be a 'scratch' or 'reg' expression. - - When matching patterns, this is equivalent to - - (match_operand:M N "scratch_operand" PRED) - - but, when generating RTL, it produces a ('scratch':M) expression. - - If the last few expressions in a 'parallel' are 'clobber' - expressions whose operands are either a hard register or - 'match_scratch', the combiner can add or delete them when - necessary. *Note Side Effects::. - -'(match_dup N)' - This expression is also a placeholder for operand number N. It is - used when the operand needs to appear more than once in the insn. - - In construction, 'match_dup' acts just like 'match_operand': the - operand is substituted into the insn being constructed. But in - matching, 'match_dup' behaves differently. It assumes that operand - number N has already been determined by a 'match_operand' appearing - earlier in the recognition template, and it matches only an - identical-looking expression. - - Note that 'match_dup' should not be used to tell the compiler that - a particular register is being used for two operands (example: - 'add' that adds one register to another; the second register is - both an input operand and the output operand). Use a matching - constraint (*note Simple Constraints::) for those. '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. - -'(match_operator:M N PREDICATE [OPERANDS...])' - 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 N, and whose operands - are constructed from the patterns OPERANDS. - - When matching an expression, it matches an expression if the - function PREDICATE returns nonzero on that expression _and_ the - patterns OPERANDS match the operands of the expression. - - Suppose that the function '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 MODE: - - 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); - } - - Then the following pattern will match any RTL expression consisting - of a commutative operator applied to two general operands: - - (match_operator:SI 3 "commutative_operator" - [(match_operand:SI 1 "general_operand" "g") - (match_operand:SI 2 "general_operand" "g")]) - - Here the vector '[OPERANDS...]' 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 'match_operand'.) Operand 3 of the - insn will be the entire commutative expression: use 'GET_CODE - (operands[3])' to see which commutative operator was used. - - The machine mode M of 'match_operator' works like that of - '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 'match_operator' is used in a pattern for matching an insn, it - usually best if the operand number of the '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 'match_operator'. The - operand of the insn which corresponds to the 'match_operator' never - has any constraints because it is never reloaded as a whole. - However, if parts of its OPERANDS are matched by 'match_operand' - patterns, those parts may have constraints of their own. - -'(match_op_dup:M N[OPERANDS...])' - Like 'match_dup', except that it applies to operators instead of - operands. When constructing an insn, operand number N will be - substituted at this point. But in matching, 'match_op_dup' behaves - differently. It assumes that operand number N has already been - determined by a 'match_operator' appearing earlier in the - recognition template, and it matches only an identical-looking - expression. - -'(match_parallel N PREDICATE [SUBPAT...])' - This pattern is a placeholder for an insn that consists of a - '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 N will be substituted at - this point. When matching an insn, it matches if the body of the - insn is a 'parallel' expression with at least as many elements as - the vector of SUBPAT expressions in the 'match_parallel', if each - SUBPAT matches the corresponding element of the 'parallel', _and_ - the function PREDICATE returns nonzero on the 'parallel' that is - the body of the insn. It is the responsibility of the predicate to - validate elements of the 'parallel' beyond those listed in the - 'match_parallel'. - - A typical use of 'match_parallel' is to match load and store - multiple expressions, which can contain a variable number of - elements in a 'parallel'. For example, - - (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") - - This example comes from 'a29k.md'. The function - 'load_multiple_operation' is defined in 'a29k.c' and checks that - subsequent elements in the 'parallel' are the same as the 'set' in - the pattern, except that they are referencing subsequent registers - and memory locations. - - An insn that matches this pattern might look like: - - (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))))]) - -'(match_par_dup N [SUBPAT...])' - Like 'match_op_dup', but for 'match_parallel' instead of - 'match_operator'. - - -File: gccint.info, Node: Output Template, Next: Output Statement, Prev: RTL Template, Up: Machine Desc - -16.5 Output Templates and Operand Substitution -============================================== - -The "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 '%' 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 '%' followed by a digit N says to output -operand N at that point in the string. - - '%' 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 'PRINT_OPERAND' can -define additional letters with nonstandard meanings. - - '%cDIGIT' can be used to substitute an operand that is a constant value -without the syntax that normally indicates an immediate operand. - - '%nDIGIT' is like '%cDIGIT' except that the value of the constant is -negated before printing. - - '%aDIGIT' 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. - - '%lDIGIT' is used to substitute a 'label_ref' into a jump instruction. - - '%=' 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. - - '%' followed by a punctuation character specifies a substitution that -does not use an operand. Only one case is standard: '%%' outputs a '%' -into the assembler code. Other nonstandard cases can be defined in the -'PRINT_OPERAND' macro. You must also define which punctuation -characters are valid with the 'PRINT_OPERAND_PUNCT_VALID_P' macro. - - The template may generate multiple assembler instructions. Write the -text for the instructions, with '\;' between them. - - 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 '%' 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 'movel' in MIT syntax is 'move.l' in Motorola -syntax. The same file of patterns is used for both kinds of output -syntax, but the character sequence '%.' is used in each place where -Motorola syntax wants a period. The 'PRINT_OPERAND' macro for Motorola -syntax defines the sequence to output a period; the macro for MIT syntax -defines it to do nothing. - - As a special case, a template consisting of the single character '#' -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 'define_insn' that needs to emit -multiple assembler instructions, and there is a matching 'define_split' -already defined, then you can simply use '#' as the output template -instead of writing an output template that emits the multiple assembler -instructions. - - If the macro 'ASSEMBLER_DIALECT' is defined, you can use construct of -the form '{option0|option1|option2}' in the templates. These describe -multiple variants of assembler language syntax. *Note Instruction -Output::. - - -File: gccint.info, Node: Output Statement, Next: Predicates, Prev: Output Template, Up: Machine Desc - -16.6 C Statements for 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 '@', 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 (*note Multi-Alternative::). For example, if a -target machine has a two-address add instruction 'addr' to add into a -register and another 'addm' to add a register to memory, you might write -this pattern: - - (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") - - If the output control string starts with a '*', then it is not an -output template but rather a piece of C program that should compute a -template. It should execute a '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 '\'. - - 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 'operands', whose C data type is -'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 'INTVAL' is an integer on -the host machine. If the host machine has more bits in an 'int' than -the target machine has in the mode in which the constant will be used, -then some of the bits you get from 'INTVAL' will be superfluous. For -proper results, you must carefully disregard the values of those bits. - - It is possible to output an assembler instruction and then go on to -output or compute more of them, using the subroutine 'output_asm_insn'. -This receives two arguments: a template-string and a vector of operands. -The vector may be 'operands', or it may be another array of 'rtx' that -you declare locally and initialize yourself. - - 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 '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, 'clrreg' -for registers and 'clrmem' for memory locations. Here is how a pattern -could use 'which_alternative' to choose between them: - - (define_insn "" - [(set (match_operand:SI 0 "general_operand" "=r,m") - (const_int 0))] - "" - { - return (which_alternative == 0 - ? "clrreg %0" : "clrmem %0"); - }) - - The example above, where the assembler code to generate was _solely_ -determined by the alternative, could also have been specified as -follows, having the output control string start with a '@': - - (define_insn "" - [(set (match_operand:SI 0 "general_operand" "=r,m") - (const_int 0))] - "" - "@ - clrreg %0 - clrmem %0") - - If you just need a little bit of C code in one (or a few) alternatives, -you can use '*' inside of a '@' multi-alternative template: - - (define_insn "" - [(set (match_operand:SI 0 "general_operand" "=r,<,m") - (const_int 0))] - "" - "@ - clrreg %0 - * return stack_mem_p (operands[0]) ? \"push 0\" : \"clrmem %0\"; - clrmem %0") - - -File: gccint.info, Node: Predicates, Next: Constraints, Prev: Output Statement, Up: Machine Desc - -16.7 Predicates -=============== - -A predicate determines whether a 'match_operand' or '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 -'match_operand' have names that end in '_operand', and those used with -'match_operator' have names that end in '_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 -'match_operand' or 'match_operator' specifies. In this section, the -first argument is called OP and the second argument 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 (*note 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. - - Most predicates handle their MODE argument in a uniform manner. If -MODE is 'VOIDmode' (unspecified), then OP can have any mode. If MODE is -anything else, then OP must have the same mode, unless OP is a -'CONST_INT' or integer 'CONST_DOUBLE'. These RTL expressions always -have 'VOIDmode', so it would be counterproductive to check that their -mode matches. Instead, predicates that accept 'CONST_INT' and/or -integer 'CONST_DOUBLE' check that the value stored in the constant will -fit in the requested mode. - - Predicates with this behavior are called "normal". '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 MODE argument are -called "special". The generic predicates 'address_operand' and -'pmode_register_operand' are special predicates. '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. - - -File: gccint.info, Node: Machine-Independent Predicates, Next: Defining Predicates, Up: Predicates - -16.7.1 Machine-Independent Predicates -------------------------------------- - -These are the generic predicates available to all back ends. They are -defined in 'recog.c'. The first category of predicates allow only -constant, or "immediate", operands. - - -- Function: immediate_operand - This predicate allows any sort of constant that fits in MODE. It - is an appropriate choice for instructions that take operands that - must be constant. - - -- Function: const_int_operand - This predicate allows any 'CONST_INT' expression that fits in MODE. - It is an appropriate choice for an immediate operand that does not - allow a symbol or label. - - -- Function: const_double_operand - This predicate accepts any 'CONST_DOUBLE' expression that has - exactly MODE. If MODE is 'VOIDmode', it will also accept - 'CONST_INT'. It is intended for immediate floating point - constants. - -The second category of predicates allow only some kind of machine -register. - - -- Function: register_operand - This predicate allows any 'REG' or 'SUBREG' expression that is - valid for MODE. It is often suitable for arithmetic instruction - operands on a RISC machine. - - -- Function: pmode_register_operand - This is a slight variant on 'register_operand' which works around a - limitation in the machine-description reader. - - (match_operand N "pmode_register_operand" CONSTRAINT) - - means exactly what - - (match_operand:P N "register_operand" CONSTRAINT) - - would mean, if the machine-description reader accepted ':P' mode - suffixes. Unfortunately, it cannot, because 'Pmode' is an alias - for some other mode, and might vary with machine-specific options. - *Note Misc::. - - -- Function: scratch_operand - This predicate allows hard registers and 'SCRATCH' expressions, but - not pseudo-registers. It is used internally by 'match_scratch'; it - should not be used directly. - -The third category of predicates allow only some kind of memory -reference. - - -- Function: memory_operand - This predicate allows any valid reference to a quantity of mode - MODE in memory, as determined by the weak form of - 'GO_IF_LEGITIMATE_ADDRESS' (*note Addressing Modes::). - - -- Function: address_operand - This predicate is a little unusual; it allows any operand that is a - valid expression for the _address_ of a quantity of mode MODE, - again determined by the weak form of 'GO_IF_LEGITIMATE_ADDRESS'. - To first order, if '(mem:MODE (EXP))' is acceptable to - 'memory_operand', then EXP is acceptable to 'address_operand'. - Note that EXP does not necessarily have the mode MODE. - - -- Function: indirect_operand - This is a stricter form of 'memory_operand' which allows only - memory references with a 'general_operand' as the address - expression. New uses of this predicate are discouraged, because - 'general_operand' is very permissive, so it's hard to tell what an - '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. - - -- Function: push_operand - This predicate allows a memory reference suitable for pushing a - value onto the stack. This will be a 'MEM' which refers to - 'stack_pointer_rtx', with a side-effect in its address expression - (*note Incdec::); which one is determined by the 'STACK_PUSH_CODE' - macro (*note Frame Layout::). - - -- Function: pop_operand - This predicate allows a memory reference suitable for popping a - value off the stack. Again, this will be a 'MEM' referring to - 'stack_pointer_rtx', with a side-effect in its address expression. - However, this time 'STACK_POP_CODE' is expected. - -The fourth category of predicates allow some combination of the above -operands. - - -- Function: nonmemory_operand - This predicate allows any immediate or register operand valid for - MODE. - - -- Function: nonimmediate_operand - This predicate allows any register or memory operand valid for - MODE. - - -- Function: general_operand - This predicate allows any immediate, register, or memory operand - valid for MODE. - -Finally, there are two generic operator predicates. - - -- Function: comparison_operator - This predicate matches any expression which performs an arithmetic - comparison in MODE; that is, 'COMPARISON_P' is true for the - expression code. - - -- Function: ordered_comparison_operator - This predicate matches any expression which performs an arithmetic - comparison in MODE and whose expression code is valid for integer - modes; that is, the expression code will be one of 'eq', 'ne', - 'lt', 'ltu', 'le', 'leu', 'gt', 'gtu', 'ge', 'geu'. - - -File: gccint.info, Node: Defining Predicates, Prev: Machine-Independent Predicates, Up: Predicates - -16.7.2 Defining Machine-Specific Predicates -------------------------------------------- - -Many machines have requirements for their operands that cannot be -expressed precisely using the generic predicates. You can define -additional predicates using 'define_predicate' and -'define_special_predicate' expressions. These expressions have three -operands: - - * The name of the predicate, as it will be referred to in - 'match_operand' or 'match_operator' expressions. - - * An RTL expression which evaluates to true if the predicate allows - the operand OP, false if it does not. This expression can only use - the following RTL codes: - - 'MATCH_OPERAND' - When written inside a predicate expression, a 'MATCH_OPERAND' - expression evaluates to true if the predicate it names would - allow OP. The operand number and constraint are ignored. Due - to limitations in 'genrecog', you can only refer to generic - predicates and predicates that have already been defined. - - 'MATCH_CODE' - This expression evaluates to true if OP or a specified - subexpression of 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 'MATCH_CODE' will be - true. - - The second operand is a string constant which indicates what - subexpression of OP to examine. If it is absent or the empty - string, 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 OP, for - the second and subsequent characters it is the result of the - previous character. A digit N extracts 'XEXP (E, N)'; a - letter L extracts 'XVECEXP (E, 0, N)' where N is the - alphabetic ordinal of L (0 for 'a', 1 for 'b', and so on). - The 'MATCH_CODE' then examines the RTX code of the - subexpression extracted by the complete string. It is not - possible to extract components of an 'rtvec' that is not at - position 0 within its RTX object. - - 'MATCH_TEST' - This expression has one operand, a string constant containing - a C expression. The predicate's arguments, OP and MODE, are - available with those names in the C expression. The - 'MATCH_TEST' evaluates to true if the C expression evaluates - to a nonzero value. 'MATCH_TEST' expressions must not have - side effects. - - 'AND' - 'IOR' - 'NOT' - 'IF_THEN_ELSE' - The basic 'MATCH_' expressions can be combined using these - logical operators, which have the semantics of the C operators - '&&', '||', '!', and '? :' respectively. As in Common Lisp, - you may give an 'AND' or 'IOR' expression an arbitrary number - of arguments; this has exactly the same effect as writing a - chain of two-argument 'AND' or 'IOR' expressions. - - * An optional block of C code, which should execute 'return true' if - the predicate is found to match and 'return false' if it does not. - It must not have any side effects. The predicate arguments, OP and - MODE, are available with those names. - - If a code block is present in a predicate definition, then the RTL - expression must evaluate to true _and_ the code block must execute - '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. - - The program 'genrecog' scans 'define_predicate' and -'define_special_predicate' expressions to determine which RTX codes are -possibly allowed. You should always make this explicit in the RTL -predicate expression, using 'MATCH_OPERAND' and 'MATCH_CODE'. - - Here is an example of a simple predicate definition, from the IA64 -machine description: - - ;; True if OP is a '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)"))) - -And here is another, showing the use of the C block. - - ;; True if 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)); - }) - - Predicates written with 'define_predicate' automatically include a test -that MODE is 'VOIDmode', or OP has the same mode as MODE, or OP is a -'CONST_INT' or 'CONST_DOUBLE'. They do _not_ check specifically for -integer '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 'CONST_INT' or -'CONST_DOUBLE' that the generic predicates provide, use a -'MATCH_OPERAND' subexpression to call 'const_int_operand', -'const_double_operand', or 'immediate_operand'. - - Predicates written with 'define_special_predicate' do not get any -automatic mode checks, and are treated as having special mode handling -by 'genrecog'. - - The program '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 'CPU-protos.h'. - - -File: gccint.info, Node: Constraints, Next: Standard Names, Prev: Predicates, Up: Machine Desc - -16.8 Operand Constraints -======================== - -Each '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. - - 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. Side-effects aren't allowed in operands -of inline 'asm', unless '<' or '>' constraints are used, because there -is no guarantee that the side-effects will happen exactly once in an -instruction that can update the addressing register. - -* 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. -* Disable Insn Alternatives:: Disable insn alternatives using the 'enabled' attribute. -* Define Constraints:: How to define machine-specific constraints. -* C Constraint Interface:: How to test constraints from C code. - - -File: gccint.info, Node: Simple Constraints, Next: Multi-Alternative, Up: Constraints - -16.8.1 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: - -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. - -'m' - A memory operand is allowed, with any kind of address that the - machine supports in general. Note that the letter used for the - general memory constraint can be re-defined by a back end using the - 'TARGET_MEM_CONSTRAINT' macro. - -'o' - A memory operand is allowed, but only if the address is - "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. - - 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 'o' is valid only when accompanied - by both '<' (if the target machine has predecrement addressing) and - '>' (if the target machine has preincrement addressing). - -'V' - A memory operand that is not offsettable. In other words, anything - that would fit the 'm' constraint but not the 'o' constraint. - -'<' - A memory operand with autodecrement addressing (either predecrement - or postdecrement) is allowed. In inline 'asm' this constraint is - only allowed if the operand is used exactly once in an instruction - that can handle the side-effects. Not using an operand with '<' in - constraint string in the inline 'asm' pattern at all or using it in - multiple instructions isn't valid, because the side-effects - wouldn't be performed or would be performed more than once. - Furthermore, on some targets the operand with '<' in constraint - string must be accompanied by special instruction suffixes like - '%U0' instruction suffix on PowerPC or '%P0' on IA-64. - -'>' - A memory operand with autoincrement addressing (either preincrement - or postincrement) is allowed. In inline 'asm' the same - restrictions as for '<' apply. - -'r' - A register operand is allowed provided that it is in a general - register. - -'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. - -'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 - 'n' rather than 'i'. - -'I', 'J', 'K', ... 'P' - Other letters in the range 'I' through '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, '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. - -'E' - An immediate floating operand (expression 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). - -'F' - An immediate floating operand (expression code 'const_double' or - 'const_vector') is allowed. - -'G', 'H' - 'G' and 'H' may be defined in a machine-dependent fashion to permit - immediate floating operands in particular ranges of values. - -'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 's' instead of '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 - -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 'moveq' instruction. We arrange for - this to happen by defining the letter 'K' to mean "any integer - outside the range -128 to 127", and then specifying 'Ks' in the - operand constraints. - -'g' - Any register, memory or immediate integer operand is allowed, - except for registers that are not general registers. - -'X' - Any operand whatsoever is allowed, even if it does not satisfy - 'general_operand'. This is normally used in the constraint of a - 'match_scratch' when certain alternatives will not actually require - a scratch register. - -'0', '1', '2', ... '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 '10' be interpreted as - matching either operand 1 _or_ operand 0. Should this be desired, - one can use multiple alternatives instead. - - This is called a "matching constraint" and what it really means is - that the assembler has only a single operand that fills two roles - 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 machines an add instruction really has only two operands, one - of them an input-output operand: - - addl #35,r12 - - 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. - - 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, '*x' as - an input operand will match '*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. - -'p' - An operand that is a valid memory address is allowed. This is for - "load address" and "push address" instructions. - - 'p' in the constraint must be accompanied by 'address_operand' as - the predicate in the 'match_operand'. This predicate interprets - the mode specified in the 'match_operand' as the mode of the memory - reference for which the address would be valid. - -OTHER-LETTERS - Other letters can be defined in machine-dependent fashion to stand - for particular classes of registers or other arbitrary operand - types. 'd', 'a' and 'f' are defined on the 68000/68020 to stand - for data, address and floating point registers. - - 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: - - (define_insn "" - [(set (match_operand:SI 0 "general_operand" "=r") - (plus:SI (match_dup 0) - (match_operand:SI 1 "general_operand" "r")))] - "" - "...") - -which has two operands, one of which must appear in two places, and - - (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")))] - "" - "...") - -which has three operands, two of which are required by a constraint to -be identical. If we are considering an insn of the form - - (insn N PREV NEXT - (set (reg:SI 3) - (plus:SI (reg:SI 6) (reg:SI 109))) - ...) - -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: - - (insn N2 PREV N - (set (reg:SI 3) (reg:SI 6)) - ...) - - (insn N N2 NEXT - (set (reg:SI 3) - (plus:SI (reg:SI 3) (reg:SI 109))) - ...) - - 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 _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. - - * 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 'i'. If any possible - constant value is accepted, then nothing less than 'i' will do; if - the predicate is more selective, then the constraints may also be - more selective. - - * 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. - - * A nonoffsettable memory reference can be reloaded by copying the - address into a register. So if the constraint uses the letter 'o', - all memory references are taken care of. - - * 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 'o' or 'm', constant operands are not a problem. - - * 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. - - 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 'SImode' to produce a 'DImode' -result, but only if the registers are correctly sign extended. This -predicate for the input operands accepts a 'sign_extend' of an 'SImode' -register. Write the constraint to indicate the type of register that is -required for the operand of the 'sign_extend'. - - -File: gccint.info, Node: Multi-Alternative, Next: Class Preferences, Prev: Simple Constraints, Up: Constraints - -16.8.2 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. Here is how it is done for fullword logical-or on the -68000: - - (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")))] - ...) - - The first alternative has 'm' (memory) for operand 0, '0' for operand 1 -(meaning it must match operand 0), and 'dKs' for operand 2. The second -alternative has 'd' (data register) for operand 0, '0' for operand 1, -and 'dmKs' for operand 2. The '=' and '%' in the constraints apply to -all the alternatives; their meaning is explained in the next section -(*note Class Preferences::). - - 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 '?' and '!' -characters: - -'?' - Disparage slightly the alternative that the '?' appears in, as a - choice when no alternative applies exactly. The compiler regards - this alternative as one unit more costly for each '?' that appears - in it. - -'!' - Disparage severely the alternative that the '!' appears in. This - alternative can still be used if it fits without reloading, but if - reloading is needed, some other alternative will be used. - - 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 'which_alternative', which is the -ordinal number of the alternative that was actually satisfied (0 for the -first, 1 for the second alternative, etc.). *Note Output Statement::. - - -File: gccint.info, Node: Class Preferences, Next: Modifiers, Prev: Multi-Alternative, Up: Constraints - -16.8.3 Register Class Preferences ---------------------------------- - -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 'd' and 'a' that specify classes of registers. The -pseudo register is put in whichever class gets the most "votes". The -constraint letters 'g' and '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. - - -File: gccint.info, Node: Modifiers, Next: Machine Constraints, Prev: Class Preferences, Up: Constraints - -16.8.4 Constraint Modifier Characters -------------------------------------- - -Here are constraint modifier characters. - -'=' - Means that this operand is write-only for this instruction: the - previous value is discarded and replaced by output data. - -'+' - 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. '=' identifies an output; '+' - identifies an operand that is both input and output; all other - operands are assumed to be input only. - - If you specify '=' or '+' in a constraint, you put it in the first - character of the constraint string. - -'&' - Means (in a particular alternative) that this operand is an - "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. - - '&' applies only to the alternative in which it is written. In - constraints with multiple alternatives, sometimes one alternative - requires '&' while others do not. See, for example, the '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 'mulsi3' insn of the ARM. - - '&' does not obviate the need to write '='. - -'%' - 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. 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: - - (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")))] - ...) - 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 - 'define_peephole2' and 'define_split's performed after reload - cannot rely on '%' to make the intended insn match. - -'#' - 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. - -'*' - Says that the following character should be ignored when choosing - register preferences. '*' has no effect on the meaning of the - constraint as a constraint, and no effect on reloading. For LRA - '*' additionally disparages slightly the alternative if the - following character matches the operand. - - 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, '*' is used so that the 'd' - constraint letter (for data register) is ignored when computing - register preferences. - - (define_insn "extendhisi2" - [(set (match_operand:SI 0 "general_operand" "=*d,a") - (sign_extend:SI - (match_operand:HI 1 "general_operand" "0,g")))] - ...) - - -File: gccint.info, Node: Machine Constraints, Next: Disable Insn Alternatives, Prev: Modifiers, Up: Constraints - -16.8.5 Constraints for Particular Machines ------------------------------------------- - -Whenever possible, you should use the general-purpose constraint letters -in '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 'm' and 'r' (for memory and -general-purpose registers respectively; *note Simple Constraints::), and -'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 'asm' statements; therefore, some of the constraints are not -particularly useful for '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 '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. - -_AArch64 family--'config/aarch64/constraints.md'_ - 'k' - The stack pointer register ('SP') - - 'w' - Floating point or SIMD vector register - - 'I' - Integer constant that is valid as an immediate operand in an - 'ADD' instruction - - 'J' - Integer constant that is valid as an immediate operand in a - 'SUB' instruction (once negated) - - 'K' - Integer constant that can be used with a 32-bit logical - instruction - - 'L' - Integer constant that can be used with a 64-bit logical - instruction - - 'M' - Integer constant that is valid as an immediate operand in a - 32-bit 'MOV' pseudo instruction. The 'MOV' may be assembled - to one of several different machine instructions depending on - the value - - 'N' - Integer constant that is valid as an immediate operand in a - 64-bit 'MOV' pseudo instruction - - 'S' - An absolute symbolic address or a label reference - - 'Y' - Floating point constant zero - - 'Z' - Integer constant zero - - 'Ush' - The high part (bits 12 and upwards) of the pc-relative address - of a symbol within 4GB of the instruction - - 'Q' - A memory address which uses a single base register with no - offset - - 'Ump' - A memory address suitable for a load/store pair instruction in - SI, DI, SF and DF modes - -_ARC --'config/arc/constraints.md'_ - 'q' - Registers usable in ARCompact 16-bit instructions: 'r0'-'r3', - 'r12'-'r15'. This constraint can only match when the '-mq' - option is in effect. - - 'e' - Registers usable as base-regs of memory addresses in ARCompact - 16-bit memory instructions: 'r0'-'r3', 'r12'-'r15', 'sp'. - This constraint can only match when the '-mq' option is in - effect. - 'D' - ARC FPX (dpfp) 64-bit registers. 'D0', 'D1'. - - 'I' - A signed 12-bit integer constant. - - 'Cal' - constant for arithmetic/logical operations. This might be any - constant that can be put into a long immediate by the assmbler - or linker without involving a PIC relocation. - - 'K' - A 3-bit unsigned integer constant. - - 'L' - A 6-bit unsigned integer constant. - - 'CnL' - One's complement of a 6-bit unsigned integer constant. - - 'CmL' - Two's complement of a 6-bit unsigned integer constant. - - 'M' - A 5-bit unsigned integer constant. - - 'O' - A 7-bit unsigned integer constant. - - 'P' - A 8-bit unsigned integer constant. - - 'H' - Any const_double value. - -_ARM family--'config/arm/constraints.md'_ - 'w' - VFP floating-point register - - 'G' - The floating-point constant 0.0 - - '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 - - 'J' - Integer in the range -4095 to 4095 - - 'K' - Integer that satisfies constraint 'I' when inverted (ones - complement) - - 'L' - Integer that satisfies constraint 'I' when negated (twos - complement) - - 'M' - Integer in the range 0 to 32 - - 'Q' - A memory reference where the exact address is in a single - register (''m'' is preferable for 'asm' statements) - - 'R' - An item in the constant pool - - 'S' - A symbol in the text segment of the current file - - 'Uv' - A memory reference suitable for VFP load/store insns - (reg+constant offset) - - 'Uy' - A memory reference suitable for iWMMXt load/store - instructions. - - 'Uq' - A memory reference suitable for the ARMv4 ldrsb instruction. - -_AVR family--'config/avr/constraints.md'_ - 'l' - Registers from r0 to r15 - - 'a' - Registers from r16 to r23 - - 'd' - Registers from r16 to r31 - - 'w' - Registers from r24 to r31. These registers can be used in - 'adiw' command - - 'e' - Pointer register (r26-r31) - - 'b' - Base pointer register (r28-r31) - - 'q' - Stack pointer register (SPH:SPL) - - 't' - Temporary register r0 - - 'x' - Register pair X (r27:r26) - - 'y' - Register pair Y (r29:r28) - - 'z' - Register pair Z (r31:r30) - - 'I' - Constant greater than -1, less than 64 - - 'J' - Constant greater than -64, less than 1 - - 'K' - Constant integer 2 - - 'L' - Constant integer 0 - - 'M' - Constant that fits in 8 bits - - 'N' - Constant integer -1 - - 'O' - Constant integer 8, 16, or 24 - - 'P' - Constant integer 1 - - 'G' - A floating point constant 0.0 - - 'Q' - A memory address based on Y or Z pointer with displacement. - -_Epiphany--'config/epiphany/constraints.md'_ - 'U16' - An unsigned 16-bit constant. - - 'K' - An unsigned 5-bit constant. - - 'L' - A signed 11-bit constant. - - 'Cm1' - A signed 11-bit constant added to -1. Can only match when the - '-m1reg-REG' option is active. - - 'Cl1' - Left-shift of -1, i.e., a bit mask with a block of leading - ones, the rest being a block of trailing zeroes. Can only - match when the '-m1reg-REG' option is active. - - 'Cr1' - Right-shift of -1, i.e., a bit mask with a trailing block of - ones, the rest being zeroes. Or to put it another way, one - less than a power of two. Can only match when the - '-m1reg-REG' option is active. - - 'Cal' - Constant for arithmetic/logical operations. This is like 'i', - except that for position independent code, no symbols / - expressions needing relocations are allowed. - - 'Csy' - Symbolic constant for call/jump instruction. - - 'Rcs' - The register class usable in short insns. This is a register - class constraint, and can thus drive register allocation. - This constraint won't match unless '-mprefer-short-insn-regs' - is in effect. - - 'Rsc' - The the register class of registers that can be used to hold a - sibcall call address. I.e., a caller-saved register. - - 'Rct' - Core control register class. - - 'Rgs' - The register group usable in short insns. This constraint - does not use a register class, so that it only passively - matches suitable registers, and doesn't drive register - allocation. - - 'Car' - Constant suitable for the addsi3_r pattern. This is a valid - offset For byte, halfword, or word addressing. - - 'Rra' - Matches the return address if it can be replaced with the link - register. - - 'Rcc' - Matches the integer condition code register. - - 'Sra' - Matches the return address if it is in a stack slot. - - 'Cfm' - Matches control register values to switch fp mode, which are - encapsulated in 'UNSPEC_FP_MODE'. - -_CR16 Architecture--'config/cr16/cr16.h'_ - - 'b' - Registers from r0 to r14 (registers without stack pointer) - - 't' - Register from r0 to r11 (all 16-bit registers) - - 'p' - Register from r12 to r15 (all 32-bit registers) - - 'I' - Signed constant that fits in 4 bits - - 'J' - Signed constant that fits in 5 bits - - 'K' - Signed constant that fits in 6 bits - - 'L' - Unsigned constant that fits in 4 bits - - 'M' - Signed constant that fits in 32 bits - - 'N' - Check for 64 bits wide constants for add/sub instructions - - 'G' - Floating point constant that is legal for store immediate - -_Hewlett-Packard PA-RISC--'config/pa/pa.h'_ - 'a' - General register 1 - - 'f' - Floating point register - - 'q' - Shift amount register - - 'x' - Floating point register (deprecated) - - 'y' - Upper floating point register (32-bit), floating point - register (64-bit) - - 'Z' - Any register - - 'I' - Signed 11-bit integer constant - - 'J' - Signed 14-bit integer constant - - 'K' - Integer constant that can be deposited with a 'zdepi' - instruction - - 'L' - Signed 5-bit integer constant - - 'M' - Integer constant 0 - - 'N' - Integer constant that can be loaded with a 'ldil' instruction - - 'O' - Integer constant whose value plus one is a power of 2 - - 'P' - Integer constant that can be used for 'and' operations in - 'depi' and 'extru' instructions - - 'S' - Integer constant 31 - - 'U' - Integer constant 63 - - 'G' - Floating-point constant 0.0 - - 'A' - A 'lo_sum' data-linkage-table memory operand - - 'Q' - A memory operand that can be used as the destination operand - of an integer store instruction - - 'R' - A scaled or unscaled indexed memory operand - - 'T' - A memory operand for floating-point loads and stores - - 'W' - A register indirect memory operand - -_picoChip family--'picochip.h'_ - 'k' - Stack register. - - 'f' - Pointer register. A register which can be used to access - memory without supplying an offset. Any other register can be - used to access memory, but will need a constant offset. In - the case of the offset being zero, it is more efficient to use - a pointer register, since this reduces code size. - - 't' - A twin register. A register which may be paired with an - adjacent register to create a 32-bit register. - - 'a' - Any absolute memory address (e.g., symbolic constant, symbolic - constant + offset). - - 'I' - 4-bit signed integer. - - 'J' - 4-bit unsigned integer. - - 'K' - 8-bit signed integer. - - 'M' - Any constant whose absolute value is no greater than 4-bits. - - 'N' - 10-bit signed integer - - 'O' - 16-bit signed integer. - -_PowerPC and IBM RS6000--'config/rs6000/constraints.md'_ - 'b' - Address base register - - 'd' - Floating point register (containing 64-bit value) - - 'f' - Floating point register (containing 32-bit value) - - 'v' - Altivec vector register - - 'wa' - Any VSX register if the -mvsx option was used or NO_REGS. - - 'wd' - VSX vector register to hold vector double data or NO_REGS. - - 'wf' - VSX vector register to hold vector float data or NO_REGS. - - 'wg' - If '-mmfpgpr' was used, a floating point register or NO_REGS. - - 'wl' - Floating point register if the LFIWAX instruction is enabled - or NO_REGS. - - 'wm' - VSX register if direct move instructions are enabled, or - NO_REGS. - - 'wn' - No register (NO_REGS). - - 'wr' - General purpose register if 64-bit instructions are enabled or - NO_REGS. - - 'ws' - VSX vector register to hold scalar double values or NO_REGS. - - 'wt' - VSX vector register to hold 128 bit integer or NO_REGS. - - 'wu' - Altivec register to use for float/32-bit int loads/stores or - NO_REGS. - - 'wv' - Altivec register to use for double loads/stores or NO_REGS. - - 'ww' - FP or VSX register to perform float operations under '-mvsx' - or NO_REGS. - - 'wx' - Floating point register if the STFIWX instruction is enabled - or NO_REGS. - - 'wy' - VSX vector register to hold scalar float values or NO_REGS. - - 'wz' - Floating point register if the LFIWZX instruction is enabled - or NO_REGS. - - 'wD' - Int constant that is the element number of the 64-bit scalar - in a vector. - - 'wQ' - A memory address that will work with the 'lq' and 'stq' - instructions. - - 'h' - 'MQ', 'CTR', or 'LINK' register - - 'q' - 'MQ' register - - 'c' - 'CTR' register - - 'l' - 'LINK' register - - 'x' - 'CR' register (condition register) number 0 - - 'y' - 'CR' register (condition register) - - 'z' - 'XER[CA]' carry bit (part of the XER register) - - 'I' - Signed 16-bit constant - - 'J' - Unsigned 16-bit constant shifted left 16 bits (use 'L' instead - for 'SImode' constants) - - 'K' - Unsigned 16-bit constant - - 'L' - Signed 16-bit constant shifted left 16 bits - - 'M' - Constant larger than 31 - - 'N' - Exact power of 2 - - 'O' - Zero - - 'P' - Constant whose negation is a signed 16-bit constant - - 'G' - Floating point constant that can be loaded into a register - with one instruction per word - - 'H' - Integer/Floating point constant that can be loaded into a - register using three instructions - - 'm' - Memory operand. Normally, 'm' does not allow addresses that - update the base register. If '<' or '>' constraint is also - used, they are allowed and therefore on PowerPC targets in - that case it is only safe to use 'm<>' in an 'asm' statement - if that 'asm' statement accesses the operand exactly once. - The 'asm' statement must also use '%U<OPNO>' as a placeholder - for the "update" flag in the corresponding load or store - instruction. For example: - - asm ("st%U0 %1,%0" : "=m<>" (mem) : "r" (val)); - - is correct but: - - asm ("st %1,%0" : "=m<>" (mem) : "r" (val)); - - is not. - - 'es' - A "stable" memory operand; that is, one which does not include - any automodification of the base register. This used to be - useful when 'm' allowed automodification of the base register, - but as those are now only allowed when '<' or '>' is used, - 'es' is basically the same as 'm' without '<' and '>'. - - 'Q' - Memory operand that is an offset from a register (it is - usually better to use 'm' or 'es' in 'asm' statements) - - 'Z' - Memory operand that is an indexed or indirect from a register - (it is usually better to use 'm' or 'es' in 'asm' statements) - - 'R' - AIX TOC entry - - 'a' - Address operand that is an indexed or indirect from a register - ('p' is preferable for 'asm' statements) - - 'S' - Constant suitable as a 64-bit mask operand - - 'T' - Constant suitable as a 32-bit mask operand - - 'U' - System V Release 4 small data area reference - - 't' - AND masks that can be performed by two rldic{l, r} - instructions - - 'W' - Vector constant that does not require memory - - 'j' - Vector constant that is all zeros. - -_Intel 386--'config/i386/constraints.md'_ - 'R' - Legacy register--the eight integer registers available on all - i386 processors ('a', 'b', 'c', 'd', 'si', 'di', 'bp', 'sp'). - - 'q' - Any register accessible as 'Rl'. In 32-bit mode, 'a', 'b', - 'c', and 'd'; in 64-bit mode, any integer register. - - 'Q' - Any register accessible as 'Rh': 'a', 'b', 'c', and 'd'. - - '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. - - 'a' - The 'a' register. - - 'b' - The 'b' register. - - 'c' - The 'c' register. - - 'd' - The 'd' register. - - 'S' - The 'si' register. - - 'D' - The 'di' register. - - 'A' - The 'a' and 'd' registers. This class is used for - instructions that return double word results in the 'ax:dx' - register pair. Single word values will be allocated either in - 'ax' or 'dx'. For example on i386 the following implements - 'rdtsc': - - unsigned long long rdtsc (void) - { - unsigned long long tick; - __asm__ __volatile__("rdtsc":"=A"(tick)); - return tick; - } - - This is not correct on x86_64 as it would allocate tick in - either 'ax' or 'dx'. You have to use the following variant - instead: - - unsigned long long rdtsc (void) - { - unsigned int tickl, tickh; - __asm__ __volatile__("rdtsc":"=a"(tickl),"=d"(tickh)); - return ((unsigned long long)tickh << 32)|tickl; - } - - 'f' - Any 80387 floating-point (stack) register. - - 't' - Top of 80387 floating-point stack ('%st(0)'). - - 'u' - Second from top of 80387 floating-point stack ('%st(1)'). - - 'y' - Any MMX register. - - 'x' - Any SSE register. - - 'Yz' - First SSE register ('%xmm0'). - - 'Y2' - Any SSE register, when SSE2 is enabled. - - 'Yi' - Any SSE register, when SSE2 and inter-unit moves are enabled. - - 'Ym' - Any MMX register, when inter-unit moves are enabled. - - 'I' - Integer constant in the range 0 ... 31, for 32-bit shifts. - - 'J' - Integer constant in the range 0 ... 63, for 64-bit shifts. - - 'K' - Signed 8-bit integer constant. - - 'L' - '0xFF' or '0xFFFF', for andsi as a zero-extending move. - - 'M' - 0, 1, 2, or 3 (shifts for the 'lea' instruction). - - 'N' - Unsigned 8-bit integer constant (for 'in' and 'out' - instructions). - - 'O' - Integer constant in the range 0 ... 127, for 128-bit shifts. - - 'G' - Standard 80387 floating point constant. - - 'C' - Standard SSE floating point constant. - - 'e' - 32-bit signed integer constant, or a symbolic reference known - to fit that range (for immediate operands in sign-extending - x86-64 instructions). - - 'Z' - 32-bit unsigned integer constant, or a symbolic reference - known to fit that range (for immediate operands in - zero-extending x86-64 instructions). - -_Intel IA-64--'config/ia64/ia64.h'_ - 'a' - General register 'r0' to 'r3' for 'addl' instruction - - 'b' - Branch register - - 'c' - Predicate register ('c' as in "conditional") - - 'd' - Application register residing in M-unit - - 'e' - Application register residing in I-unit - - 'f' - Floating-point register - - 'm' - Memory operand. If used together with '<' or '>', the operand - can have postincrement and postdecrement which require - printing with '%Pn' on IA-64. - - 'G' - Floating-point constant 0.0 or 1.0 - - 'I' - 14-bit signed integer constant - - 'J' - 22-bit signed integer constant - - 'K' - 8-bit signed integer constant for logical instructions - - 'L' - 8-bit adjusted signed integer constant for compare pseudo-ops - - 'M' - 6-bit unsigned integer constant for shift counts - - 'N' - 9-bit signed integer constant for load and store - postincrements - - 'O' - The constant zero - - 'P' - 0 or -1 for 'dep' instruction - - 'Q' - Non-volatile memory for floating-point loads and stores - - 'R' - Integer constant in the range 1 to 4 for 'shladd' instruction - - 'S' - Memory operand except postincrement and postdecrement. This - is now roughly the same as 'm' when not used together with '<' - or '>'. - -_FRV--'config/frv/frv.h'_ - 'a' - Register in the class 'ACC_REGS' ('acc0' to 'acc7'). - - 'b' - Register in the class 'EVEN_ACC_REGS' ('acc0' to 'acc7'). - - 'c' - Register in the class 'CC_REGS' ('fcc0' to 'fcc3' and 'icc0' - to 'icc3'). - - 'd' - Register in the class 'GPR_REGS' ('gr0' to 'gr63'). - - 'e' - Register in the class 'EVEN_REGS' ('gr0' to 'gr63'). Odd - registers are excluded not in the class but through the use of - a machine mode larger than 4 bytes. - - 'f' - Register in the class 'FPR_REGS' ('fr0' to 'fr63'). - - 'h' - Register in the class 'FEVEN_REGS' ('fr0' to 'fr63'). Odd - registers are excluded not in the class but through the use of - a machine mode larger than 4 bytes. - - 'l' - Register in the class 'LR_REG' (the 'lr' register). - - 'q' - Register in the class 'QUAD_REGS' ('gr2' to '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. - - 't' - Register in the class 'ICC_REGS' ('icc0' to 'icc3'). - - 'u' - Register in the class 'FCC_REGS' ('fcc0' to 'fcc3'). - - 'v' - Register in the class 'ICR_REGS' ('cc4' to 'cc7'). - - 'w' - Register in the class 'FCR_REGS' ('cc0' to 'cc3'). - - 'x' - Register in the class 'QUAD_FPR_REGS' ('fr0' to '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. - - 'z' - Register in the class 'SPR_REGS' ('lcr' and 'lr'). - - 'A' - Register in the class 'QUAD_ACC_REGS' ('acc0' to 'acc7'). - - 'B' - Register in the class 'ACCG_REGS' ('accg0' to 'accg7'). - - 'C' - Register in the class 'CR_REGS' ('cc0' to 'cc7'). - - 'G' - Floating point constant zero - - 'I' - 6-bit signed integer constant - - 'J' - 10-bit signed integer constant - - 'L' - 16-bit signed integer constant - - 'M' - 16-bit unsigned integer constant - - 'N' - 12-bit signed integer constant that is negative--i.e. in the - range of -2048 to -1 - - 'O' - Constant zero - - 'P' - 12-bit signed integer constant that is greater than zero--i.e. - in the range of 1 to 2047. - -_Blackfin family--'config/bfin/constraints.md'_ - 'a' - P register - - 'd' - D register - - 'z' - A call clobbered P register. - - 'qN' - A single register. If N is in the range 0 to 7, the - corresponding D register. If it is 'A', then the register P0. - - 'D' - Even-numbered D register - - 'W' - Odd-numbered D register - - 'e' - Accumulator register. - - 'A' - Even-numbered accumulator register. - - 'B' - Odd-numbered accumulator register. - - 'b' - I register - - 'v' - B register - - 'f' - M register - - 'c' - Registers used for circular buffering, i.e. I, B, or L - registers. - - 'C' - The CC register. - - 't' - LT0 or LT1. - - 'k' - LC0 or LC1. - - 'u' - LB0 or LB1. - - 'x' - Any D, P, B, M, I or L register. - - 'y' - Additional registers typically used only in prologues and - epilogues: RETS, RETN, RETI, RETX, RETE, ASTAT, SEQSTAT and - USP. - - 'w' - Any register except accumulators or CC. - - 'Ksh' - Signed 16 bit integer (in the range -32768 to 32767) - - 'Kuh' - Unsigned 16 bit integer (in the range 0 to 65535) - - 'Ks7' - Signed 7 bit integer (in the range -64 to 63) - - 'Ku7' - Unsigned 7 bit integer (in the range 0 to 127) - - 'Ku5' - Unsigned 5 bit integer (in the range 0 to 31) - - 'Ks4' - Signed 4 bit integer (in the range -8 to 7) - - 'Ks3' - Signed 3 bit integer (in the range -3 to 4) - - 'Ku3' - Unsigned 3 bit integer (in the range 0 to 7) - - 'PN' - Constant N, where N is a single-digit constant in the range 0 - to 4. - - 'PA' - An integer equal to one of the MACFLAG_XXX constants that is - suitable for use with either accumulator. - - 'PB' - An integer equal to one of the MACFLAG_XXX constants that is - suitable for use only with accumulator A1. - - 'M1' - Constant 255. - - 'M2' - Constant 65535. - - 'J' - An integer constant with exactly a single bit set. - - 'L' - An integer constant with all bits set except exactly one. - - 'H' - - 'Q' - Any SYMBOL_REF. - -_M32C--'config/m32c/m32c.c'_ - 'Rsp' - 'Rfb' - 'Rsb' - '$sp', '$fb', '$sb'. - - 'Rcr' - Any control register, when they're 16 bits wide (nothing if - control registers are 24 bits wide) - - 'Rcl' - Any control register, when they're 24 bits wide. - - 'R0w' - 'R1w' - 'R2w' - 'R3w' - $r0, $r1, $r2, $r3. - - 'R02' - $r0 or $r2, or $r2r0 for 32 bit values. - - 'R13' - $r1 or $r3, or $r3r1 for 32 bit values. - - 'Rdi' - A register that can hold a 64 bit value. - - 'Rhl' - $r0 or $r1 (registers with addressable high/low bytes) - - 'R23' - $r2 or $r3 - - 'Raa' - Address registers - - 'Raw' - Address registers when they're 16 bits wide. - - 'Ral' - Address registers when they're 24 bits wide. - - 'Rqi' - Registers that can hold QI values. - - 'Rad' - Registers that can be used with displacements ($a0, $a1, $sb). - - 'Rsi' - Registers that can hold 32 bit values. - - 'Rhi' - Registers that can hold 16 bit values. - - 'Rhc' - Registers chat can hold 16 bit values, including all control - registers. - - 'Rra' - $r0 through R1, plus $a0 and $a1. - - 'Rfl' - The flags register. - - 'Rmm' - The memory-based pseudo-registers $mem0 through $mem15. - - 'Rpi' - Registers that can hold pointers (16 bit registers for r8c, - m16c; 24 bit registers for m32cm, m32c). - - 'Rpa' - Matches multiple registers in a PARALLEL to form a larger - register. Used to match function return values. - - 'Is3' - -8 ... 7 - - 'IS1' - -128 ... 127 - - 'IS2' - -32768 ... 32767 - - 'IU2' - 0 ... 65535 - - 'In4' - -8 ... -1 or 1 ... 8 - - 'In5' - -16 ... -1 or 1 ... 16 - - 'In6' - -32 ... -1 or 1 ... 32 - - 'IM2' - -65536 ... -1 - - 'Ilb' - An 8 bit value with exactly one bit set. - - 'Ilw' - A 16 bit value with exactly one bit set. - - 'Sd' - The common src/dest memory addressing modes. - - 'Sa' - Memory addressed using $a0 or $a1. - - 'Si' - Memory addressed with immediate addresses. - - 'Ss' - Memory addressed using the stack pointer ($sp). - - 'Sf' - Memory addressed using the frame base register ($fb). - - 'Ss' - Memory addressed using the small base register ($sb). - - 'S1' - $r1h - -_MeP--'config/mep/constraints.md'_ - - 'a' - The $sp register. - - 'b' - The $tp register. - - 'c' - Any control register. - - 'd' - Either the $hi or the $lo register. - - 'em' - Coprocessor registers that can be directly loaded ($c0-$c15). - - 'ex' - Coprocessor registers that can be moved to each other. - - 'er' - Coprocessor registers that can be moved to core registers. - - 'h' - The $hi register. - - 'j' - The $rpc register. - - 'l' - The $lo register. - - 't' - Registers which can be used in $tp-relative addressing. - - 'v' - The $gp register. - - 'x' - The coprocessor registers. - - 'y' - The coprocessor control registers. - - 'z' - The $0 register. - - 'A' - User-defined register set A. - - 'B' - User-defined register set B. - - 'C' - User-defined register set C. - - 'D' - User-defined register set D. - - 'I' - Offsets for $gp-rel addressing. - - 'J' - Constants that can be used directly with boolean insns. - - 'K' - Constants that can be moved directly to registers. - - 'L' - Small constants that can be added to registers. - - 'M' - Long shift counts. - - 'N' - Small constants that can be compared to registers. - - 'O' - Constants that can be loaded into the top half of registers. - - 'S' - Signed 8-bit immediates. - - 'T' - Symbols encoded for $tp-rel or $gp-rel addressing. - - 'U' - Non-constant addresses for loading/saving coprocessor - registers. - - 'W' - The top half of a symbol's value. - - 'Y' - A register indirect address without offset. - - 'Z' - Symbolic references to the control bus. - -_MicroBlaze--'config/microblaze/constraints.md'_ - 'd' - A general register ('r0' to 'r31'). - - 'z' - A status register ('rmsr', '$fcc1' to '$fcc7'). - -_MIPS--'config/mips/constraints.md'_ - 'd' - An address register. This is equivalent to 'r' unless - generating MIPS16 code. - - 'f' - A floating-point register (if available). - - 'h' - Formerly the 'hi' register. This constraint is no longer - supported. - - 'l' - The 'lo' register. Use this register to store values that are - no bigger than a word. - - 'x' - The concatenated 'hi' and 'lo' registers. Use this register - to store doubleword values. - - 'c' - A register suitable for use in an indirect jump. This will - always be '$25' for '-mabicalls'. - - 'v' - Register '$3'. Do not use this constraint in new code; it is - retained only for compatibility with glibc. - - 'y' - Equivalent to 'r'; retained for backwards compatibility. - - 'z' - A floating-point condition code register. - - 'I' - A signed 16-bit constant (for arithmetic instructions). - - 'J' - Integer zero. - - 'K' - An unsigned 16-bit constant (for logic instructions). - - 'L' - A signed 32-bit constant in which the lower 16 bits are zero. - Such constants can be loaded using 'lui'. - - 'M' - A constant that cannot be loaded using 'lui', 'addiu' or - 'ori'. - - 'N' - A constant in the range -65535 to -1 (inclusive). - - 'O' - A signed 15-bit constant. - - 'P' - A constant in the range 1 to 65535 (inclusive). - - 'G' - Floating-point zero. - - 'R' - An address that can be used in a non-macro load or store. - - 'ZC' - When compiling microMIPS code, this constraint matches a - memory operand whose address is formed from a base register - and a 12-bit offset. These operands can be used for microMIPS - instructions such as 'll' and 'sc'. When not compiling for - microMIPS code, 'ZC' is equivalent to 'R'. - - 'ZD' - When compiling microMIPS code, this constraint matches an - address operand that is formed from a base register and a - 12-bit offset. These operands can be used for microMIPS - instructions such as 'prefetch'. When not compiling for - microMIPS code, 'ZD' is equivalent to 'p'. - -_Motorola 680x0--'config/m68k/constraints.md'_ - 'a' - Address register - - 'd' - Data register - - 'f' - 68881 floating-point register, if available - - 'I' - Integer in the range 1 to 8 - - 'J' - 16-bit signed number - - 'K' - Signed number whose magnitude is greater than 0x80 - - 'L' - Integer in the range -8 to -1 - - 'M' - Signed number whose magnitude is greater than 0x100 - - 'N' - Range 24 to 31, rotatert:SI 8 to 1 expressed as rotate - - 'O' - 16 (for rotate using swap) - - 'P' - Range 8 to 15, rotatert:HI 8 to 1 expressed as rotate - - 'R' - Numbers that mov3q can handle - - 'G' - Floating point constant that is not a 68881 constant - - 'S' - Operands that satisfy 'm' when -mpcrel is in effect - - 'T' - Operands that satisfy 's' when -mpcrel is not in effect - - 'Q' - Address register indirect addressing mode - - 'U' - Register offset addressing - - 'W' - const_call_operand - - 'Cs' - symbol_ref or const - - 'Ci' - const_int - - 'C0' - const_int 0 - - 'Cj' - Range of signed numbers that don't fit in 16 bits - - 'Cmvq' - Integers valid for mvq - - 'Capsw' - Integers valid for a moveq followed by a swap - - 'Cmvz' - Integers valid for mvz - - 'Cmvs' - Integers valid for mvs - - 'Ap' - push_operand - - 'Ac' - Non-register operands allowed in clr - -_Moxie--'config/moxie/constraints.md'_ - 'A' - An absolute address - - 'B' - An offset address - - 'W' - A register indirect memory operand - - 'I' - A constant in the range of 0 to 255. - - 'N' - A constant in the range of 0 to -255. - -_MSP430-'config/msp430/constraints.md'_ - - 'R12' - Register R12. - - 'R13' - Register R13. - - 'K' - Integer constant 1. - - 'L' - Integer constant -1^20..1^19. - - 'M' - Integer constant 1-4. - - 'Ya' - Memory references which do not require an extended MOVX - instruction. - - 'Yl' - Memory reference, labels only. - - 'Ys' - Memory reference, stack only. - -_NDS32--'config/nds32/constraints.md'_ - 'w' - LOW register class $r0 to $r7 constraint for V3/V3M ISA. - 'l' - LOW register class $r0 to $r7. - 'd' - MIDDLE register class $r0 to $r11, $r16 to $r19. - 'h' - HIGH register class $r12 to $r14, $r20 to $r31. - 't' - Temporary assist register $ta (i.e. $r15). - 'k' - Stack register $sp. - 'Iu03' - Unsigned immediate 3-bit value. - 'In03' - Negative immediate 3-bit value in the range of -7-0. - 'Iu04' - Unsigned immediate 4-bit value. - 'Is05' - Signed immediate 5-bit value. - 'Iu05' - Unsigned immediate 5-bit value. - 'In05' - Negative immediate 5-bit value in the range of -31-0. - 'Ip05' - Unsigned immediate 5-bit value for movpi45 instruction with - range 16-47. - 'Iu06' - Unsigned immediate 6-bit value constraint for addri36.sp - instruction. - 'Iu08' - Unsigned immediate 8-bit value. - 'Iu09' - Unsigned immediate 9-bit value. - 'Is10' - Signed immediate 10-bit value. - 'Is11' - Signed immediate 11-bit value. - 'Is15' - Signed immediate 15-bit value. - 'Iu15' - Unsigned immediate 15-bit value. - 'Ic15' - A constant which is not in the range of imm15u but ok for bclr - instruction. - 'Ie15' - A constant which is not in the range of imm15u but ok for bset - instruction. - 'It15' - A constant which is not in the range of imm15u but ok for btgl - instruction. - 'Ii15' - A constant whose compliment value is in the range of imm15u - and ok for bitci instruction. - 'Is16' - Signed immediate 16-bit value. - 'Is17' - Signed immediate 17-bit value. - 'Is19' - Signed immediate 19-bit value. - 'Is20' - Signed immediate 20-bit value. - 'Ihig' - The immediate value that can be simply set high 20-bit. - 'Izeb' - The immediate value 0xff. - 'Izeh' - The immediate value 0xffff. - 'Ixls' - The immediate value 0x01. - 'Ix11' - The immediate value 0x7ff. - 'Ibms' - The immediate value with power of 2. - 'Ifex' - The immediate value with power of 2 minus 1. - 'U33' - Memory constraint for 333 format. - 'U45' - Memory constraint for 45 format. - 'U37' - Memory constraint for 37 format. - -_Nios II family--'config/nios2/constraints.md'_ - - 'I' - Integer that is valid as an immediate operand in an - instruction taking a signed 16-bit number. Range -32768 to - 32767. - - 'J' - Integer that is valid as an immediate operand in an - instruction taking an unsigned 16-bit number. Range 0 to - 65535. - - 'K' - Integer that is valid as an immediate operand in an - instruction taking only the upper 16-bits of a 32-bit number. - Range 32-bit numbers with the lower 16-bits being 0. - - 'L' - Integer that is valid as an immediate operand for a shift - instruction. Range 0 to 31. - - 'M' - Integer that is valid as an immediate operand for only the - value 0. Can be used in conjunction with the format modifier - 'z' to use 'r0' instead of '0' in the assembly output. - - 'N' - Integer that is valid as an immediate operand for a custom - instruction opcode. Range 0 to 255. - - 'S' - Matches immediates which are addresses in the small data - section and therefore can be added to 'gp' as a 16-bit - immediate to re-create their 32-bit value. - - 'T' - A 'const' wrapped 'UNSPEC' expression, representing a - supported PIC or TLS relocation. - -_PDP-11--'config/pdp11/constraints.md'_ - 'a' - Floating point registers AC0 through AC3. These can be loaded - from/to memory with a single instruction. - - 'd' - Odd numbered general registers (R1, R3, R5). These are used - for 16-bit multiply operations. - - 'f' - Any of the floating point registers (AC0 through AC5). - - 'G' - Floating point constant 0. - - 'I' - An integer constant that fits in 16 bits. - - 'J' - An integer constant whose low order 16 bits are zero. - - 'K' - An integer constant that does not meet the constraints for - codes 'I' or 'J'. - - 'L' - The integer constant 1. - - 'M' - The integer constant -1. - - 'N' - The integer constant 0. - - 'O' - Integer constants -4 through -1 and 1 through 4; shifts by - these amounts are handled as multiple single-bit shifts rather - than a single variable-length shift. - - 'Q' - A memory reference which requires an additional word (address - or offset) after the opcode. - - 'R' - A memory reference that is encoded within the opcode. - -_RL78--'config/rl78/constraints.md'_ - - 'Int3' - An integer constant in the range 1 ... 7. - 'Int8' - An integer constant in the range 0 ... 255. - 'J' - An integer constant in the range -255 ... 0 - 'K' - The integer constant 1. - 'L' - The integer constant -1. - 'M' - The integer constant 0. - 'N' - The integer constant 2. - 'O' - The integer constant -2. - 'P' - An integer constant in the range 1 ... 15. - 'Qbi' - The built-in compare types-eq, ne, gtu, ltu, geu, and leu. - 'Qsc' - The synthetic compare types-gt, lt, ge, and le. - 'Wab' - A memory reference with an absolute address. - 'Wbc' - A memory reference using 'BC' as a base register, with an - optional offset. - 'Wca' - A memory reference using 'AX', 'BC', 'DE', or 'HL' for the - address, for calls. - 'Wcv' - A memory reference using any 16-bit register pair for the - address, for calls. - 'Wd2' - A memory reference using 'DE' as a base register, with an - optional offset. - 'Wde' - A memory reference using 'DE' as a base register, without any - offset. - 'Wfr' - Any memory reference to an address in the far address space. - 'Wh1' - A memory reference using 'HL' as a base register, with an - optional one-byte offset. - 'Whb' - A memory reference using 'HL' as a base register, with 'B' or - 'C' as the index register. - 'Whl' - A memory reference using 'HL' as a base register, without any - offset. - 'Ws1' - A memory reference using 'SP' as a base register, with an - optional one-byte offset. - 'Y' - Any memory reference to an address in the near address space. - 'A' - The 'AX' register. - 'B' - The 'BC' register. - 'D' - The 'DE' register. - 'R' - 'A' through 'L' registers. - 'S' - The 'SP' register. - 'T' - The 'HL' register. - 'Z08W' - The 16-bit 'R8' register. - 'Z10W' - The 16-bit 'R10' register. - 'Zint' - The registers reserved for interrupts ('R24' to 'R31'). - 'a' - The 'A' register. - 'b' - The 'B' register. - 'c' - The 'C' register. - 'd' - The 'D' register. - 'e' - The 'E' register. - 'h' - The 'H' register. - 'l' - The 'L' register. - 'v' - The virtual registers. - 'w' - The 'PSW' register. - 'x' - The 'X' register. - -_RX--'config/rx/constraints.md'_ - 'Q' - An address which does not involve register indirect addressing - or pre/post increment/decrement addressing. - - 'Symbol' - A symbol reference. - - 'Int08' - A constant in the range -256 to 255, inclusive. - - 'Sint08' - A constant in the range -128 to 127, inclusive. - - 'Sint16' - A constant in the range -32768 to 32767, inclusive. - - 'Sint24' - A constant in the range -8388608 to 8388607, inclusive. - - 'Uint04' - A constant in the range 0 to 15, inclusive. - -_SPARC--'config/sparc/sparc.h'_ - 'f' - Floating-point register on the SPARC-V8 architecture and lower - floating-point register on the SPARC-V9 architecture. - - 'e' - Floating-point register. It is equivalent to 'f' on the - SPARC-V8 architecture and contains both lower and upper - floating-point registers on the SPARC-V9 architecture. - - 'c' - Floating-point condition code register. - - 'd' - Lower floating-point register. It is only valid on the - SPARC-V9 architecture when the Visual Instruction Set is - available. - - 'b' - Floating-point register. It is only valid on the SPARC-V9 - architecture when the Visual Instruction Set is available. - - 'h' - 64-bit global or out register for the SPARC-V8+ architecture. - - 'C' - The constant all-ones, for floating-point. - - 'A' - Signed 5-bit constant - - 'D' - A vector constant - - 'I' - Signed 13-bit constant - - 'J' - Zero - - 'K' - 32-bit constant with the low 12 bits clear (a constant that - can be loaded with the 'sethi' instruction) - - 'L' - A constant in the range supported by 'movcc' instructions - (11-bit signed immediate) - - 'M' - A constant in the range supported by 'movrcc' instructions - (10-bit signed immediate) - - 'N' - Same as 'K', except that it verifies that bits that are not in - the lower 32-bit range are all zero. Must be used instead of - 'K' for modes wider than 'SImode' - - 'O' - The constant 4096 - - 'G' - Floating-point zero - - 'H' - Signed 13-bit constant, sign-extended to 32 or 64 bits - - 'P' - The constant -1 - - 'Q' - Floating-point constant whose integral representation can be - moved into an integer register using a single sethi - instruction - - 'R' - Floating-point constant whose integral representation can be - moved into an integer register using a single mov instruction - - 'S' - Floating-point constant whose integral representation can be - moved into an integer register using a high/lo_sum instruction - sequence - - 'T' - Memory address aligned to an 8-byte boundary - - 'U' - Even register - - 'W' - Memory address for 'e' constraint registers - - 'w' - Memory address with only a base register - - 'Y' - Vector zero - -_SPU--'config/spu/spu.h'_ - 'a' - An immediate which can be loaded with the il/ila/ilh/ilhu - instructions. const_int is treated as a 64 bit value. - - 'c' - An immediate for and/xor/or instructions. const_int is - treated as a 64 bit value. - - 'd' - An immediate for the 'iohl' instruction. const_int is treated - as a 64 bit value. - - 'f' - An immediate which can be loaded with 'fsmbi'. - - 'A' - An immediate which can be loaded with the il/ila/ilh/ilhu - instructions. const_int is treated as a 32 bit value. - - 'B' - An immediate for most arithmetic instructions. const_int is - treated as a 32 bit value. - - 'C' - An immediate for and/xor/or instructions. const_int is - treated as a 32 bit value. - - 'D' - An immediate for the 'iohl' instruction. const_int is treated - as a 32 bit value. - - 'I' - A constant in the range [-64, 63] for shift/rotate - instructions. - - 'J' - An unsigned 7-bit constant for conversion/nop/channel - instructions. - - 'K' - A signed 10-bit constant for most arithmetic instructions. - - 'M' - A signed 16 bit immediate for 'stop'. - - 'N' - An unsigned 16-bit constant for 'iohl' and 'fsmbi'. - - 'O' - An unsigned 7-bit constant whose 3 least significant bits are - 0. - - 'P' - An unsigned 3-bit constant for 16-byte rotates and shifts - - 'R' - Call operand, reg, for indirect calls - - 'S' - Call operand, symbol, for relative calls. - - 'T' - Call operand, const_int, for absolute calls. - - 'U' - An immediate which can be loaded with the il/ila/ilh/ilhu - instructions. const_int is sign extended to 128 bit. - - 'W' - An immediate for shift and rotate instructions. const_int is - treated as a 32 bit value. - - 'Y' - An immediate for and/xor/or instructions. const_int is sign - extended as a 128 bit. - - 'Z' - An immediate for the 'iohl' instruction. const_int is sign - extended to 128 bit. - -_S/390 and zSeries--'config/s390/s390.h'_ - 'a' - Address register (general purpose register except r0) - - 'c' - Condition code register - - 'd' - Data register (arbitrary general purpose register) - - 'f' - Floating-point register - - 'I' - Unsigned 8-bit constant (0-255) - - 'J' - Unsigned 12-bit constant (0-4095) - - 'K' - Signed 16-bit constant (-32768-32767) - - 'L' - Value appropriate as displacement. - '(0..4095)' - for short displacement - '(-524288..524287)' - for long displacement - - 'M' - Constant integer with a value of 0x7fffffff. - - 'N' - Multiple letter constraint followed by 4 parameter letters. - '0..9:' - number of the part counting from most to least - significant - 'H,Q:' - mode of the part - 'D,S,H:' - mode of the containing operand - '0,F:' - value of the other parts (F--all bits set) - The constraint matches if the specified part of a constant has - a value different from its other parts. - - 'Q' - Memory reference without index register and with short - displacement. - - 'R' - Memory reference with index register and short displacement. - - 'S' - Memory reference without index register but with long - displacement. - - 'T' - Memory reference with index register and long displacement. - - 'U' - Pointer with short displacement. - - 'W' - Pointer with long displacement. - - 'Y' - Shift count operand. - -_Score family--'config/score/score.h'_ - 'd' - Registers from r0 to r32. - - 'e' - Registers from r0 to r16. - - 't' - r8--r11 or r22--r27 registers. - - 'h' - hi register. - - 'l' - lo register. - - 'x' - hi + lo register. - - 'q' - cnt register. - - 'y' - lcb register. - - 'z' - scb register. - - 'a' - cnt + lcb + scb register. - - 'c' - cr0--cr15 register. - - 'b' - cp1 registers. - - 'f' - cp2 registers. - - 'i' - cp3 registers. - - 'j' - cp1 + cp2 + cp3 registers. - - 'I' - High 16-bit constant (32-bit constant with 16 LSBs zero). - - 'J' - Unsigned 5 bit integer (in the range 0 to 31). - - 'K' - Unsigned 16 bit integer (in the range 0 to 65535). - - 'L' - Signed 16 bit integer (in the range -32768 to 32767). - - 'M' - Unsigned 14 bit integer (in the range 0 to 16383). - - 'N' - Signed 14 bit integer (in the range -8192 to 8191). - - 'Z' - Any SYMBOL_REF. - -_Xstormy16--'config/stormy16/stormy16.h'_ - 'a' - Register r0. - - 'b' - Register r1. - - 'c' - Register r2. - - 'd' - Register r8. - - 'e' - Registers r0 through r7. - - 't' - Registers r0 and r1. - - 'y' - The carry register. - - 'z' - Registers r8 and r9. - - 'I' - A constant between 0 and 3 inclusive. - - 'J' - A constant that has exactly one bit set. - - 'K' - A constant that has exactly one bit clear. - - 'L' - A constant between 0 and 255 inclusive. - - 'M' - A constant between -255 and 0 inclusive. - - 'N' - A constant between -3 and 0 inclusive. - - 'O' - A constant between 1 and 4 inclusive. - - 'P' - A constant between -4 and -1 inclusive. - - 'Q' - A memory reference that is a stack push. - - 'R' - A memory reference that is a stack pop. - - 'S' - A memory reference that refers to a constant address of known - value. - - 'T' - The register indicated by Rx (not implemented yet). - - 'U' - A constant that is not between 2 and 15 inclusive. - - 'Z' - The constant 0. - -_TI C6X family--'config/c6x/constraints.md'_ - 'a' - Register file A (A0-A31). - - 'b' - Register file B (B0-B31). - - 'A' - Predicate registers in register file A (A0-A2 on C64X and - higher, A1 and A2 otherwise). - - 'B' - Predicate registers in register file B (B0-B2). - - 'C' - A call-used register in register file B (B0-B9, B16-B31). - - 'Da' - Register file A, excluding predicate registers (A3-A31, plus - A0 if not C64X or higher). - - 'Db' - Register file B, excluding predicate registers (B3-B31). - - 'Iu4' - Integer constant in the range 0 ... 15. - - 'Iu5' - Integer constant in the range 0 ... 31. - - 'In5' - Integer constant in the range -31 ... 0. - - 'Is5' - Integer constant in the range -16 ... 15. - - 'I5x' - Integer constant that can be the operand of an ADDA or a SUBA - insn. - - 'IuB' - Integer constant in the range 0 ... 65535. - - 'IsB' - Integer constant in the range -32768 ... 32767. - - 'IsC' - Integer constant in the range -2^{20} ... 2^{20} - 1. - - 'Jc' - Integer constant that is a valid mask for the clr instruction. - - 'Js' - Integer constant that is a valid mask for the set instruction. - - 'Q' - Memory location with A base register. - - 'R' - Memory location with B base register. - - 'S0' - On C64x+ targets, a GP-relative small data reference. - - 'S1' - Any kind of 'SYMBOL_REF', for use in a call address. - - 'Si' - Any kind of immediate operand, unless it matches the S0 - constraint. - - 'T' - Memory location with B base register, but not using a long - offset. - - 'W' - A memory operand with an address that can't be used in an - unaligned access. - - 'Z' - Register B14 (aka DP). - -_TILE-Gx--'config/tilegx/constraints.md'_ - 'R00' - 'R01' - 'R02' - 'R03' - 'R04' - 'R05' - 'R06' - 'R07' - 'R08' - 'R09' - 'R10' - Each of these represents a register constraint for an - individual register, from r0 to r10. - - 'I' - Signed 8-bit integer constant. - - 'J' - Signed 16-bit integer constant. - - 'K' - Unsigned 16-bit integer constant. - - 'L' - Integer constant that fits in one signed byte when incremented - by one (-129 ... 126). - - 'm' - Memory operand. If used together with '<' or '>', the operand - can have postincrement which requires printing with '%In' and - '%in' on TILE-Gx. For example: - - asm ("st_add %I0,%1,%i0" : "=m<>" (*mem) : "r" (val)); - - 'M' - A bit mask suitable for the BFINS instruction. - - 'N' - Integer constant that is a byte tiled out eight times. - - 'O' - The integer zero constant. - - 'P' - Integer constant that is a sign-extended byte tiled out as - four shorts. - - 'Q' - Integer constant that fits in one signed byte when incremented - (-129 ... 126), but excluding -1. - - 'S' - Integer constant that has all 1 bits consecutive and starting - at bit 0. - - 'T' - A 16-bit fragment of a got, tls, or pc-relative reference. - - 'U' - Memory operand except postincrement. This is roughly the same - as 'm' when not used together with '<' or '>'. - - 'W' - An 8-element vector constant with identical elements. - - 'Y' - A 4-element vector constant with identical elements. - - 'Z0' - The integer constant 0xffffffff. - - 'Z1' - The integer constant 0xffffffff00000000. - -_TILEPro--'config/tilepro/constraints.md'_ - 'R00' - 'R01' - 'R02' - 'R03' - 'R04' - 'R05' - 'R06' - 'R07' - 'R08' - 'R09' - 'R10' - Each of these represents a register constraint for an - individual register, from r0 to r10. - - 'I' - Signed 8-bit integer constant. - - 'J' - Signed 16-bit integer constant. - - 'K' - Nonzero integer constant with low 16 bits zero. - - 'L' - Integer constant that fits in one signed byte when incremented - by one (-129 ... 126). - - 'm' - Memory operand. If used together with '<' or '>', the operand - can have postincrement which requires printing with '%In' and - '%in' on TILEPro. For example: - - asm ("swadd %I0,%1,%i0" : "=m<>" (mem) : "r" (val)); - - 'M' - A bit mask suitable for the MM instruction. - - 'N' - Integer constant that is a byte tiled out four times. - - 'O' - The integer zero constant. - - 'P' - Integer constant that is a sign-extended byte tiled out as two - shorts. - - 'Q' - Integer constant that fits in one signed byte when incremented - (-129 ... 126), but excluding -1. - - 'T' - A symbolic operand, or a 16-bit fragment of a got, tls, or - pc-relative reference. - - 'U' - Memory operand except postincrement. This is roughly the same - as 'm' when not used together with '<' or '>'. - - 'W' - A 4-element vector constant with identical elements. - - 'Y' - A 2-element vector constant with identical elements. - -_Xtensa--'config/xtensa/constraints.md'_ - 'a' - General-purpose 32-bit register - - 'b' - One-bit boolean register - - 'A' - MAC16 40-bit accumulator register - - 'I' - Signed 12-bit integer constant, for use in MOVI instructions - - 'J' - Signed 8-bit integer constant, for use in ADDI instructions - - 'K' - Integer constant valid for BccI instructions - - 'L' - Unsigned constant valid for BccUI instructions - - -File: gccint.info, Node: Disable Insn Alternatives, Next: Define Constraints, Prev: Machine Constraints, Up: Constraints - -16.8.6 Disable insn alternatives using the 'enabled' attribute --------------------------------------------------------------- - -The 'enabled' insn attribute may be used to disable certain insn -alternatives for machine-specific reasons. This is useful when adding -new instructions to an existing pattern which are only available for -certain cpu architecture levels as specified with the '-march=' option. - - If an insn alternative is disabled, then it will never be used. The -compiler treats the constraints for the disabled alternative as -unsatisfiable. - - In order to make use of the 'enabled' attribute a back end has to add -in the machine description files: - - 1. A definition of the 'enabled' insn attribute. The attribute is - defined as usual using the 'define_attr' command. This definition - should be based on other insn attributes and/or target flags. The - 'enabled' attribute is a numeric attribute and should evaluate to - '(const_int 1)' for an enabled alternative and to '(const_int 0)' - otherwise. - 2. A definition of another insn attribute used to describe for what - reason an insn alternative might be available or not. E.g. - 'cpu_facility' as in the example below. - 3. An assignment for the second attribute to each insn definition - combining instructions which are not all available under the same - circumstances. (Note: It obviously only makes sense for - definitions with more than one alternative. Otherwise the insn - pattern should be disabled or enabled using the insn condition.) - - E.g. the following two patterns could easily be merged using the -'enabled' attribute: - - - (define_insn "*movdi_old" - [(set (match_operand:DI 0 "register_operand" "=d") - (match_operand:DI 1 "register_operand" " d"))] - "!TARGET_NEW" - "lgr %0,%1") - - (define_insn "*movdi_new" - [(set (match_operand:DI 0 "register_operand" "=d,f,d") - (match_operand:DI 1 "register_operand" " d,d,f"))] - "TARGET_NEW" - "@ - lgr %0,%1 - ldgr %0,%1 - lgdr %0,%1") - - to: - - - (define_insn "*movdi_combined" - [(set (match_operand:DI 0 "register_operand" "=d,f,d") - (match_operand:DI 1 "register_operand" " d,d,f"))] - "" - "@ - lgr %0,%1 - ldgr %0,%1 - lgdr %0,%1" - [(set_attr "cpu_facility" "*,new,new")]) - - with the 'enabled' attribute defined like this: - - - (define_attr "cpu_facility" "standard,new" (const_string "standard")) - - (define_attr "enabled" "" - (cond [(eq_attr "cpu_facility" "standard") (const_int 1) - (and (eq_attr "cpu_facility" "new") - (ne (symbol_ref "TARGET_NEW") (const_int 0))) - (const_int 1)] - (const_int 0))) - - -File: gccint.info, Node: Define Constraints, Next: C Constraint Interface, Prev: Disable Insn Alternatives, Up: Constraints - -16.8.7 Defining Machine-Specific Constraints --------------------------------------------- - -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 'reload' more information. - - Machine-specific constraints can be given names of arbitrary length, -but they must be entirely composed of letters, digits, underscores -('_'), and angle brackets ('< >'). 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 'x' is defined as a constraint name, 'xy' may not be, -and vice versa. As a consequence of this rule, no constraint may begin -with one of the generic constraint letters: 'E F V X g i m n o p r s'. - - Register constraints correspond directly to register classes. *Note -Register Classes::. There is thus not much flexibility in their -definitions. - - -- MD Expression: define_register_constraint name regclass docstring - All three arguments are string constants. NAME is the name of the - constraint, as it will appear in 'match_operand' expressions. If - NAME is a multi-letter constraint its length shall be the same for - all constraints starting with the same letter. REGCLASS can be - either the name of the corresponding register class (*note 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 'NO_REGS' when - the register class is not available on a given subarchitecture. - - DOCSTRING is a sentence documenting the meaning of the constraint. - Docstrings are explained further below. - - Non-register constraints are more like predicates: the constraint -definition gives a Boolean expression which indicates whether the -constraint matches. - - -- MD Expression: define_constraint name docstring exp - The NAME and DOCSTRING arguments are the same as for - 'define_register_constraint', but note that the docstring comes - immediately after the name for these expressions. EXP is an RTL - expression, obeying the same rules as the RTL expressions in - predicate definitions. *Note 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. - - 'match_test' C expressions have access to the following variables: - - OP - The RTL object defining the operand. - MODE - The machine mode of OP. - IVAL - 'INTVAL (OP)', if OP is a 'const_int'. - HVAL - 'CONST_DOUBLE_HIGH (OP)', if OP is an integer 'const_double'. - LVAL - 'CONST_DOUBLE_LOW (OP)', if OP is an integer 'const_double'. - RVAL - 'CONST_DOUBLE_REAL_VALUE (OP)', if OP is a floating-point - 'const_double'. - - The *VAL variables should only be used once another piece of the - expression has verified that OP is the appropriate kind of RTL - object. - - Most non-register constraints should be defined with -'define_constraint'. The remaining two definition expressions are only -appropriate for constraints that should be handled specially by 'reload' -if they fail to match. - - -- MD Expression: define_memory_constraint name docstring exp - Use this expression for constraints that match a subset of all - memory operands: that is, 'reload' can make them match by - converting the operand to the form '(mem (reg X))', where X is a - base register (from the register class specified by - 'BASE_REG_CLASS', *note 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 'Q' is defined to - represent a memory address of this type. If 'Q' is defined with - 'define_memory_constraint', a 'Q' constraint can handle any memory - operand, because 'reload' knows it can simply copy the memory - address into a base register if required. This is analogous to the - way an 'o' constraint can handle any memory operand. - - The syntax and semantics are otherwise identical to - 'define_constraint'. - - -- MD Expression: define_address_constraint name docstring exp - Use this expression for constraints that match a subset of all - address operands: that is, 'reload' can make the constraint match - by converting the operand to the form '(reg X)', again with X a - base register. - - Constraints defined with 'define_address_constraint' can only be - used with the 'address_operand' predicate, or machine-specific - predicates that work the same way. They are treated analogously to - the generic 'p' constraint. - - The syntax and semantics are otherwise identical to - 'define_constraint'. - - For historical reasons, names beginning with the letters 'G H' are -reserved for constraints that match only 'const_double's, and names -beginning with the letters 'I J K L M N O P' are reserved for -constraints that match only '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 'genpreds' can tell you did it -correctly: - - (define_constraint "[GHIJKLMNOP]..." - "DOC..." - (and (match_code "const_int") ; 'const_double' for G/H - CONDITION...)) ; usually a 'match_test' - - It is fine to use names beginning with other letters for constraints -that match 'const_double's or 'const_int's. - - Each docstring in a constraint definition should be one or more -complete sentences, marked up in Texinfo format. _They are currently -unused._ In the future they will be copied into the GCC manual, in -*note 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 'asm' -constraints causes a reload failure. - - If you put the pseudo-Texinfo directive '@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 'asm' statements. - - -File: gccint.info, Node: C Constraint Interface, Prev: Define Constraints, Up: Constraints - -16.8.8 Testing constraints from C ---------------------------------- - -It is occasionally useful to test a constraint from C code rather than -implicitly via the constraint string in a 'match_operand'. The -generated 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 *note Simple Constraints::. This may -change in the future. - - *Warning:* '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 '<' is replaced with '_l', and each '>' -with '_g'. Here are some examples: - - *Original* *Mangled* - x x - P42x P42x - P4_x P4__x - P4>x P4_gx - P4>> P4_g_g - P4_g> P4__g_g - - Throughout this section, the variable C is either a constraint in the -abstract sense, or a constant from 'enum constraint_num'; the variable M -is a mangled constraint name (usually as part of a larger identifier). - - -- Enum: constraint_num - For each machine-specific constraint, there is a corresponding - enumeration constant: 'CONSTRAINT_' plus the mangled name of the - constraint. Functions that take an '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. - - -- Function: inline bool satisfies_constraint_ M (rtx EXP) - For each machine-specific, non-register constraint M, there is one - of these functions; it returns 'true' if EXP satisfies the - constraint. These functions are only visible if 'rtl.h' was - included before 'tm_p.h'. - - -- Function: bool constraint_satisfied_p (rtx EXP, enum constraint_num - C) - Like the 'satisfies_constraint_M' functions, but the constraint to - test is given as an argument, C. If C specifies a register - constraint, this function will always return 'false'. - - -- Function: enum reg_class regclass_for_constraint (enum - constraint_num C) - Returns the register class associated with C. If C is not a - register constraint, or those registers are not available for the - currently selected subtarget, returns 'NO_REGS'. - - Here is an example use of 'satisfies_constraint_M'. In peephole -optimizations (*note 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 _not_ satisfy the 'K' constraint. (This is a simplified -version of a peephole definition from the i386 machine description.) - - (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)))] - - "") - - -File: gccint.info, Node: Standard Names, Next: Pattern Ordering, Prev: Constraints, Up: Machine Desc - -16.9 Standard Pattern Names For Generation -========================================== - -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. - -'movM' - Here 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, 'movsi' moves full-word data. - - If operand 0 is a 'subreg' with mode M of a register whose own mode - is wider than M, the effect of this instruction is to store the - specified value in the part of the register that corresponds to - mode M. Bits outside of M, but which are within the same target - word as the '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 _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, 'movM' 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. - - 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 'define_expand', then in such a case - the 'define_expand' mustn't call '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. - - 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 'change_address') that will do so may be called. - Note that 'general_operand' will fail when applied to such an - address. - - The global variable '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 '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. - - The macro 'can_create_pseudo_p' 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 'gen_reg_rtx' to allocate a new - pseudo. - - The constraints on a 'movM' must permit moving any hard register to - any other hard register provided that 'HARD_REGNO_MODE_OK' permits - mode M in both registers and 'TARGET_REGISTER_MOVE_COST' applied to - their classes returns a value of 2. - - It is obligatory to support floating point 'movM' instructions into - and out of any registers that can hold fixed point values, because - unions and structures (which have modes 'SImode' or 'DImode') can - be in those registers and they may have floating point members. - - There may also be a need to support fixed point 'movM' 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 'HARD_REGNO_MODE_OK' rejects fixed point values in - floating point registers, then the constraints of the fixed point - 'movM' instructions must be designed to avoid ever trying to reload - into a floating point register. - -'reload_inM' -'reload_outM' - These named patterns have been obsoleted by the target hook - 'secondary_reload'. - - Like 'movM', 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 'SECONDARY_RELOAD_CLASS' macro - in *note Register Classes::. - - There are special restrictions on the form of the 'match_operand's - used in these patterns. First, only the predicate for the reload - operand is examined, i.e., '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 'ALL_REGS' register class. This may relieve - ports of the burden of defining an 'ALL_REGS' constraint letter - just for these patterns. - -'movstrictM' - Like 'movM' except that if operand 0 is a 'subreg' with mode M of a - register whose natural mode is wider, the 'movstrictM' instruction - is guaranteed not to alter any of the register except the part - which belongs to mode M. - -'movmisalignM' - 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 - 'MISALIGNED_INDIRECT_REF' expression. - -'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 'define_expand' (*note Expander Definitions::) and - make the pattern fail if the restrictions are not met. - - Write the generated insn as a 'parallel' with elements being a - 'set' of one register from the appropriate memory location (you may - also need 'use' or 'clobber' elements). Use a 'match_parallel' - (*note RTL Template::) to recognize the insn. See 'rs6000.md' for - examples of the use of this insn pattern. - -'store_multiple' - Similar to '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. - -'vec_load_lanesMN' - Perform an interleaved load of several vectors from memory operand - 1 into register operand 0. Both operands have mode M. The - register operand is viewed as holding consecutive vectors of mode - N, while the memory operand is a flat array that contains the same - number of elements. The operation is equivalent to: - - int c = GET_MODE_SIZE (M) / GET_MODE_SIZE (N); - for (j = 0; j < GET_MODE_NUNITS (N); j++) - for (i = 0; i < c; i++) - operand0[i][j] = operand1[j * c + i]; - - For example, 'vec_load_lanestiv4hi' loads 8 16-bit values from - memory into a register of mode 'TI'. The register contains two - consecutive vectors of mode 'V4HI'. - - This pattern can only be used if: - TARGET_ARRAY_MODE_SUPPORTED_P (N, C) - is true. GCC assumes that, if a target supports this kind of - instruction for some mode N, it also supports unaligned loads for - vectors of mode N. - -'vec_store_lanesMN' - Equivalent to 'vec_load_lanesMN', with the memory and register - operands reversed. That is, the instruction is equivalent to: - - int c = GET_MODE_SIZE (M) / GET_MODE_SIZE (N); - for (j = 0; j < GET_MODE_NUNITS (N); j++) - for (i = 0; i < c; i++) - operand0[j * c + i] = operand1[i][j]; - - for a memory operand 0 and register operand 1. - -'vec_setM' - 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. - -'vec_extractM' - 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. - -'vec_initM' - Initialize the vector to given values. Operand 0 is the vector to - initialize and operand 1 is parallel containing values for - individual fields. - -'vcondMN' - Output a conditional vector move. Operand 0 is the destination to - receive a combination of operand 1 and operand 2, which are of mode - M, dependent on the outcome of the predicate in operand 3 which is - a vector comparison with operands of mode N in operands 4 and 5. - The modes M and N should have the same size. Operand 0 will be set - to the value OP1 & MSK | OP2 & ~MSK where MSK is computed by - element-wise evaluation of the vector comparison with a truth value - of all-ones and a false value of all-zeros. - -'vec_permM' - Output a (variable) vector permutation. Operand 0 is the - destination to receive elements from operand 1 and operand 2, which - are of mode M. Operand 3 is the "selector". It is an integral - mode vector of the same width and number of elements as mode M. - - The input elements are numbered from 0 in operand 1 through 2*N-1 - in operand 2. The elements of the selector must be computed modulo - 2*N. Note that if 'rtx_equal_p(operand1, operand2)', this can be - implemented with just operand 1 and selector elements modulo N. - - In order to make things easy for a number of targets, if there is - no 'vec_perm' pattern for mode M, but there is for mode Q where Q - is a vector of 'QImode' of the same width as M, the middle-end will - lower the mode M 'VEC_PERM_EXPR' to mode Q. - -'vec_perm_constM' - Like 'vec_perm' except that the permutation is a compile-time - constant. That is, operand 3, the "selector", is a 'CONST_VECTOR'. - - Some targets cannot perform a permutation with a variable selector, - but can efficiently perform a constant permutation. Further, the - target hook 'vec_perm_ok' is queried to determine if the specific - constant permutation is available efficiently; the named pattern is - never expanded without 'vec_perm_ok' returning true. - - There is no need for a target to supply both 'vec_permM' and - 'vec_perm_constM' if the former can trivially implement the - operation with, say, the vector constant loaded into a register. - -'pushM1' - Output a push instruction. Operand 0 is value to push. Used only - when 'PUSH_ROUNDING' is defined. For historical reason, this - pattern may be missing and in such case an 'mov' expander is used - instead, with a 'MEM' expression forming the push operation. The - 'mov' expander method is deprecated. - -'addM3' - Add operand 2 and operand 1, storing the result in operand 0. All - operands must have mode M. This can be used even on two-address - machines, by means of constraints requiring operands 1 and 0 to be - the same location. - -'addptrM3' - Like 'addM3' but is guaranteed to only be used for address - calculations. The expanded code is not allowed to clobber the - condition code. It only needs to be defined if 'addM3' sets the - condition code. If adds used for address calculations and normal - adds are not compatible it is required to expand a distinct pattern - (e.g. using an unspec). The pattern is used by LRA to emit - address calculations. 'addM3' is used if 'addptrM3' is not - defined. - -'ssaddM3', 'usaddM3' -'subM3', 'sssubM3', 'ussubM3' -'mulM3', 'ssmulM3', 'usmulM3' -'divM3', 'ssdivM3' -'udivM3', 'usdivM3' -'modM3', 'umodM3' -'uminM3', 'umaxM3' -'andM3', 'iorM3', 'xorM3' - Similar, for other arithmetic operations. - -'fmaM4' - Multiply operand 2 and operand 1, then add operand 3, storing the - result in operand 0 without doing an intermediate rounding step. - All operands must have mode M. This pattern is used to implement - the 'fma', 'fmaf', and 'fmal' builtin functions from the ISO C99 - standard. - -'fmsM4' - Like 'fmaM4', except operand 3 subtracted from the product instead - of added to the product. This is represented in the rtl as - - (fma:M OP1 OP2 (neg:M OP3)) - -'fnmaM4' - Like 'fmaM4' except that the intermediate product is negated before - being added to operand 3. This is represented in the rtl as - - (fma:M (neg:M OP1) OP2 OP3) - -'fnmsM4' - Like 'fmsM4' except that the intermediate product is negated before - subtracting operand 3. This is represented in the rtl as - - (fma:M (neg:M OP1) OP2 (neg:M OP3)) - -'sminM3', 'smaxM3' - Signed minimum and maximum operations. When used with floating - point, if both operands are zeros, or if either operand is 'NaN', - then it is unspecified which of the two operands is returned as the - result. - -'reduc_smin_M', 'reduc_smax_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. - -'reduc_umin_M', 'reduc_umax_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. - -'reduc_splus_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. - -'reduc_uplus_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. - -'sdot_prodM' -'udot_prodM' - 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. - -'ssum_widenM3' -'usum_widenM3' - 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.) - -'vec_shl_M', 'vec_shr_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. - -'vec_pack_trunc_M' - Narrow (demote) and merge the elements of two vectors. Operands 1 - and 2 are vectors of the same mode having N integral or floating - point elements of size S. Operand 0 is the resulting vector in - which 2*N elements of size N/2 are concatenated after narrowing - them down using truncation. - -'vec_pack_ssat_M', 'vec_pack_usat_M' - Narrow (demote) and merge the elements of two vectors. Operands 1 - and 2 are vectors of the same mode having N integral elements of - size S. Operand 0 is the resulting vector in which the elements of - the two input vectors are concatenated after narrowing them down - using signed/unsigned saturating arithmetic. - -'vec_pack_sfix_trunc_M', 'vec_pack_ufix_trunc_M' - Narrow, convert to signed/unsigned integral type and merge the - elements of two vectors. Operands 1 and 2 are vectors of the same - mode having N floating point elements of size S. Operand 0 is the - resulting vector in which 2*N elements of size N/2 are - concatenated. - -'vec_unpacks_hi_M', 'vec_unpacks_lo_M' - Extract and widen (promote) the high/low part of a vector of signed - integral or floating point elements. The input vector (operand 1) - has N elements of size S. Widen (promote) the high/low elements of - the vector using signed or floating point extension and place the - resulting N/2 values of size 2*S in the output vector (operand 0). - -'vec_unpacku_hi_M', 'vec_unpacku_lo_M' - Extract and widen (promote) the high/low part of a vector of - unsigned integral elements. The input vector (operand 1) has N - elements of size S. Widen (promote) the high/low elements of the - vector using zero extension and place the resulting N/2 values of - size 2*S in the output vector (operand 0). - -'vec_unpacks_float_hi_M', 'vec_unpacks_float_lo_M' -'vec_unpacku_float_hi_M', 'vec_unpacku_float_lo_M' - Extract, convert to floating point type and widen the high/low part - of a vector of signed/unsigned integral elements. The input vector - (operand 1) has N elements of size S. Convert the high/low - elements of the vector using floating point conversion and place - the resulting N/2 values of size 2*S in the output vector (operand - 0). - -'vec_widen_umult_hi_M', 'vec_widen_umult_lo_M' -'vec_widen_smult_hi_M', 'vec_widen_smult_lo_M' -'vec_widen_umult_even_M', 'vec_widen_umult_odd_M' -'vec_widen_smult_even_M', 'vec_widen_smult_odd_M' - Signed/Unsigned widening multiplication. The two inputs (operands - 1 and 2) are vectors with N signed/unsigned elements of size S. - Multiply the high/low or even/odd elements of the two vectors, and - put the N/2 products of size 2*S in the output vector (operand 0). - A target shouldn't implement even/odd pattern pair if it is less - efficient than lo/hi one. - -'vec_widen_ushiftl_hi_M', 'vec_widen_ushiftl_lo_M' -'vec_widen_sshiftl_hi_M', 'vec_widen_sshiftl_lo_M' - Signed/Unsigned widening shift left. The first input (operand 1) - is a vector with N signed/unsigned elements of size S. Operand 2 - is a constant. Shift the high/low elements of operand 1, and put - the N/2 results of size 2*S in the output vector (operand 0). - -'mulhisi3' - Multiply operands 1 and 2, which have mode 'HImode', and store a - 'SImode' product in operand 0. - -'mulqihi3', 'mulsidi3' - Similar widening-multiplication instructions of other widths. - -'umulqihi3', 'umulhisi3', 'umulsidi3' - Similar widening-multiplication instructions that do unsigned - multiplication. - -'usmulqihi3', 'usmulhisi3', 'usmulsidi3' - Similar widening-multiplication instructions that interpret the - first operand as unsigned and the second operand as signed, then do - a signed multiplication. - -'smulM3_highpart' - Perform a signed multiplication of operands 1 and 2, which have - mode M, and store the most significant half of the product in - operand 0. The least significant half of the product is discarded. - -'umulM3_highpart' - Similar, but the multiplication is unsigned. - -'maddMN4' - Multiply operands 1 and 2, sign-extend them to mode N, add operand - 3, and store the result in operand 0. Operands 1 and 2 have mode M - and operands 0 and 3 have mode N. Both modes must be integer or - fixed-point modes and N must be twice the size of M. - - In other words, 'maddMN4' is like 'mulMN3' except that it also adds - operand 3. - - These instructions are not allowed to 'FAIL'. - -'umaddMN4' - Like 'maddMN4', but zero-extend the multiplication operands instead - of sign-extending them. - -'ssmaddMN4' - Like 'maddMN4', but all involved operations must be - signed-saturating. - -'usmaddMN4' - Like 'umaddMN4', but all involved operations must be - unsigned-saturating. - -'msubMN4' - Multiply operands 1 and 2, sign-extend them to mode N, subtract the - result from operand 3, and store the result in operand 0. Operands - 1 and 2 have mode M and operands 0 and 3 have mode N. Both modes - must be integer or fixed-point modes and N must be twice the size - of M. - - In other words, 'msubMN4' is like 'mulMN3' except that it also - subtracts the result from operand 3. - - These instructions are not allowed to 'FAIL'. - -'umsubMN4' - Like 'msubMN4', but zero-extend the multiplication operands instead - of sign-extending them. - -'ssmsubMN4' - Like 'msubMN4', but all involved operations must be - signed-saturating. - -'usmsubMN4' - Like 'umsubMN4', but all involved operations must be - unsigned-saturating. - -'divmodM4' - 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 'divmodM4' but do not provide - patterns for 'divM3' and 'modM3'. 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 'divmodM4' to call - 'find_reg_note' and look for a 'REG_UNUSED' note on the quotient or - remainder and generate the appropriate instruction. - -'udivmodM4' - Similar, but does unsigned division. - -'ashlM3', 'ssashlM3', 'usashlM3' - Arithmetic-shift operand 1 left by a number of bits specified by - operand 2, and store the result in operand 0. Here 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 - 'TARGET_SHIFT_TRUNCATION_MASK'. *Note - TARGET_SHIFT_TRUNCATION_MASK::. Operand 2 is always a scalar type. - -'ashrM3', 'lshrM3', 'rotlM3', 'rotrM3' - Other shift and rotate instructions, analogous to the 'ashlM3' - instructions. Operand 2 is always a scalar type. - -'vashlM3', 'vashrM3', 'vlshrM3', 'vrotlM3', 'vrotrM3' - Vector shift and rotate instructions that take vectors as operand 2 - instead of a scalar type. - -'bswapM2' - Reverse the order of bytes of operand 1 and store the result in - operand 0. - -'negM2', 'ssnegM2', 'usnegM2' - Negate operand 1 and store the result in operand 0. - -'absM2' - Store the absolute value of operand 1 into operand 0. - -'sqrtM2' - Store the square root of operand 1 into operand 0. - - The 'sqrt' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'sqrtf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'fmodM3' - Store the remainder of dividing operand 1 by operand 2 into operand - 0, rounded towards zero to an integer. - - The 'fmod' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'fmodf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'remainderM3' - Store the remainder of dividing operand 1 by operand 2 into operand - 0, rounded to the nearest integer. - - The 'remainder' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'remainderf' - built-in function uses the mode which corresponds to the C data - type 'float'. - -'cosM2' - Store the cosine of operand 1 into operand 0. - - The 'cos' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'cosf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'sinM2' - Store the sine of operand 1 into operand 0. - - The 'sin' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'sinf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'sincosM3' - Store the cosine of operand 2 into operand 0 and the sine of - operand 2 into operand 1. - - The 'sin' and 'cos' built-in functions of C always use the mode - which corresponds to the C data type 'double' and the 'sinf' and - 'cosf' built-in function use the mode which corresponds to the C - data type 'float'. Targets that can calculate the sine and cosine - simultaneously can implement this pattern as opposed to - implementing individual 'sinM2' and 'cosM2' patterns. The 'sin' - and 'cos' built-in functions will then be expanded to the - 'sincosM3' pattern, with one of the output values left unused. - -'expM2' - Store the exponential of operand 1 into operand 0. - - The 'exp' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'expf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'logM2' - Store the natural logarithm of operand 1 into operand 0. - - The 'log' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'logf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'powM3' - Store the value of operand 1 raised to the exponent operand 2 into - operand 0. - - The 'pow' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'powf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'atan2M3' - 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 'atan2' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'atan2f' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'floorM2' - Store the largest integral value not greater than argument. - - The 'floor' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'floorf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'btruncM2' - Store the argument rounded to integer towards zero. - - The 'trunc' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'truncf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'roundM2' - Store the argument rounded to integer away from zero. - - The 'round' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'roundf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'ceilM2' - Store the argument rounded to integer away from zero. - - The 'ceil' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'ceilf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'nearbyintM2' - Store the argument rounded according to the default rounding mode - - The 'nearbyint' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'nearbyintf' - built-in function uses the mode which corresponds to the C data - type 'float'. - -'rintM2' - 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 'rint' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'rintf' built-in - function uses the mode which corresponds to the C data type - 'float'. - -'lrintMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as a signed number according to the current rounding mode - and store in operand 0 (which has mode N). - -'lroundMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as a signed number rounding to nearest and away from zero - and store in operand 0 (which has mode N). - -'lfloorMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as a signed number rounding down and store in operand 0 - (which has mode N). - -'lceilMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as a signed number rounding up and store in operand 0 (which - has mode N). - -'copysignM3' - Store a value with the magnitude of operand 1 and the sign of - operand 2 into operand 0. - - The 'copysign' built-in function of C always uses the mode which - corresponds to the C data type 'double' and the 'copysignf' - built-in function uses the mode which corresponds to the C data - type 'float'. - -'ffsM2' - Store into operand 0 one plus the index of the least significant - 1-bit of operand 1. If operand 1 is zero, store zero. 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 'ffs' built-in function of C always uses the mode which - corresponds to the C data type 'int'. - -'clzM2' - Store into operand 0 the number of leading 0-bits in X, starting at - the most significant bit position. If X is 0, the - 'CLZ_DEFINED_VALUE_AT_ZERO' (*note Misc::) macro defines if the - result is undefined or has a useful value. 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. - -'ctzM2' - Store into operand 0 the number of trailing 0-bits in X, starting - at the least significant bit position. If X is 0, the - 'CTZ_DEFINED_VALUE_AT_ZERO' (*note Misc::) macro defines if the - result is undefined or has a useful value. 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. - -'popcountM2' - Store into operand 0 the number of 1-bits in X. 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. - -'parityM2' - Store into operand 0 the parity of X, i.e. the number of 1-bits in - X modulo 2. 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. - -'one_cmplM2' - Store the bitwise-complement of operand 1 into operand 0. - -'movmemM' - Block move instruction. The destination and source blocks of - memory are the first two operands, and both are 'mem:BLK's with an - address in mode 'Pmode'. - - The number of bytes to move is the third operand, in mode M. - Usually, you specify 'Pmode' for M. However, if you can generate - better code knowing the range of valid lengths is smaller than - those representable in a full Pmode pointer, you should provide a - pattern with a mode corresponding to the range of values you can - handle efficiently (e.g., 'QImode' for values in the range 0-127; - note we avoid numbers that appear negative) and also a pattern with - 'Pmode'. - - The fourth operand is the known shared alignment of the source and - destination, in the form of a '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. - - Optional operands 5 and 6 specify expected alignment and size of - block respectively. The expected alignment differs from alignment - in operand 4 in a way that the blocks are not required to be - aligned according to it in all cases. This expected alignment is - also in bytes, just like operand 4. Expected size, when unknown, - is set to '(const_int -1)'. - - Descriptions of multiple 'movmemM' 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 M in - 'movmemM' 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. - -'movstr' - String copy instruction, with 'stpcpy' semantics. Operand 0 is an - output operand in mode 'Pmode'. The addresses of the destination - and source strings are operands 1 and 2, and both are 'mem:BLK's - with addresses in mode 'Pmode'. The execution of the expansion of - this pattern should store in operand 0 the address in which the - 'NUL' terminator was stored in the destination string. - - This patern has also several optional operands that are same as in - 'setmem'. - -'setmemM' - Block set instruction. The destination string is the first - operand, given as a 'mem:BLK' whose address is in mode 'Pmode'. - The number of bytes to set is the second operand, in mode 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 'movmemM' for a discussion of the - choice of mode. - - The fourth operand is the known alignment of the destination, in - the form of a 'const_int' rtx. Thus, if the compiler knows that - the destination is word-aligned, it may provide the value 4 for - this operand. - - Optional operands 5 and 6 specify expected alignment and size of - block respectively. The expected alignment differs from alignment - in operand 4 in a way that the blocks are not required to be - aligned according to it in all cases. This expected alignment is - also in bytes, just like operand 4. Expected size, when unknown, - is set to '(const_int -1)'. Operand 7 is the minimal size of the - block and operand 8 is the maximal size of the block (NULL if it - can not be represented as CONST_INT). Operand 9 is the probable - maximal size (i.e. we can not rely on it for correctness, but it - can be used for choosing proper code sequence for a given size). - - The use for multiple 'setmemM' is as for 'movmemM'. - -'cmpstrnM' - String compare instruction, with five operands. Operand 0 is the - output; it has mode M. The remaining four operands are like the - operands of 'movmemM'. 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 comparison terminates early if - the fetched bytes are different or if they are equal to zero. The - effect of the instruction is to store a value in operand 0 whose - sign indicates the result of the comparison. - -'cmpstrM' - String compare instruction, without known maximum length. Operand - 0 is the output; it has mode M. The second and third operand are - the blocks of memory to be compared; both are 'mem:BLK' with an - address in mode 'Pmode'. - - The fourth operand is the known shared alignment of the source and - destination, in the form of a '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 - comparison will terminate when the fetched bytes are different or - if they are equal to zero. The effect of the instruction is to - store a value in operand 0 whose sign indicates the result of the - comparison. - -'cmpmemM' - Block compare instruction, with five operands like the operands of - 'cmpstrM'. The two memory blocks specified are compared byte by - byte in lexicographic order starting at the beginning of each - block. Unlike 'cmpstrM' the instruction can prefetch any bytes in - the two memory blocks. Also unlike 'cmpstrM' the comparison will - not stop if both bytes are zero. The effect of the instruction is - to store a value in operand 0 whose sign indicates the result of - the comparison. - -'strlenM' - Compute the length of a string, with three operands. Operand 0 is - the result (of mode M), operand 1 is a '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. - -'floatMN2' - Convert signed integer operand 1 (valid for fixed point mode M) to - floating point mode N and store in operand 0 (which has mode N). - -'floatunsMN2' - Convert unsigned integer operand 1 (valid for fixed point mode M) - to floating point mode N and store in operand 0 (which has mode N). - -'fixMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as a signed number and store in operand 0 (which has mode - 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 'ftrunc' pattern. - -'fixunsMN2' - Convert operand 1 (valid for floating point mode M) to fixed point - mode N as an unsigned number and store in operand 0 (which has mode - N). This instruction's result is defined only when the value of - operand 1 is an integer. - -'ftruncM2' - Convert operand 1 (valid for floating point mode M) to an integer - value, still represented in floating point mode M, and store it in - operand 0 (valid for floating point mode M). - -'fix_truncMN2' - Like 'fixMN2' but works for any floating point value of mode M by - converting the value to an integer. - -'fixuns_truncMN2' - Like 'fixunsMN2' but works for any floating point value of mode M - by converting the value to an integer. - -'truncMN2' - Truncate operand 1 (valid for mode M) to mode N and store in - operand 0 (which has mode N). Both modes must be fixed point or - both floating point. - -'extendMN2' - Sign-extend operand 1 (valid for mode M) to mode N and store in - operand 0 (which has mode N). Both modes must be fixed point or - both floating point. - -'zero_extendMN2' - Zero-extend operand 1 (valid for mode M) to mode N and store in - operand 0 (which has mode N). Both modes must be fixed point. - -'fractMN2' - Convert operand 1 of mode M to mode N and store in operand 0 (which - has mode N). Mode M and mode N could be fixed-point to - fixed-point, signed integer to fixed-point, fixed-point to signed - integer, floating-point to fixed-point, or fixed-point to - floating-point. When overflows or underflows happen, the results - are undefined. - -'satfractMN2' - Convert operand 1 of mode M to mode N and store in operand 0 (which - has mode N). Mode M and mode N could be fixed-point to - fixed-point, signed integer to fixed-point, or floating-point to - fixed-point. When overflows or underflows happen, the instruction - saturates the results to the maximum or the minimum. - -'fractunsMN2' - Convert operand 1 of mode M to mode N and store in operand 0 (which - has mode N). Mode M and mode N could be unsigned integer to - fixed-point, or fixed-point to unsigned integer. When overflows or - underflows happen, the results are undefined. - -'satfractunsMN2' - Convert unsigned integer operand 1 of mode M to fixed-point mode N - and store in operand 0 (which has mode N). When overflows or - underflows happen, the instruction saturates the results to the - maximum or the minimum. - -'extvM' - Extract a bit-field from register operand 1, sign-extend it, and - store it in operand 0. Operand 2 specifies the width of the field - in bits and operand 3 the starting bit, which counts from the most - significant bit if 'BITS_BIG_ENDIAN' is true and from the least - significant bit otherwise. - - Operands 0 and 1 both have mode M. Operands 2 and 3 have a - target-specific mode. - -'extvmisalignM' - Extract a bit-field from memory operand 1, sign extend it, and - store it in operand 0. Operand 2 specifies the width in bits and - operand 3 the starting bit. The starting bit is always somewhere - in the first byte of operand 1; it counts from the most significant - bit if 'BITS_BIG_ENDIAN' is true and from the least significant bit - otherwise. - - Operand 0 has mode M while operand 1 has 'BLK' mode. Operands 2 - and 3 have a target-specific mode. - - The instruction must not read beyond the last byte of the - bit-field. - -'extzvM' - Like 'extvM' except that the bit-field value is zero-extended. - -'extzvmisalignM' - Like 'extvmisalignM' except that the bit-field value is - zero-extended. - -'insvM' - Insert operand 3 into a bit-field of register operand 0. Operand 1 - specifies the width of the field in bits and operand 2 the starting - bit, which counts from the most significant bit if - 'BITS_BIG_ENDIAN' is true and from the least significant bit - otherwise. - - Operands 0 and 3 both have mode M. Operands 1 and 2 have a - target-specific mode. - -'insvmisalignM' - Insert operand 3 into a bit-field of memory operand 0. Operand 1 - specifies the width of the field in bits and operand 2 the starting - bit. The starting bit is always somewhere in the first byte of - operand 0; it counts from the most significant bit if - 'BITS_BIG_ENDIAN' is true and from the least significant bit - otherwise. - - Operand 3 has mode M while operand 0 has 'BLK' mode. Operands 1 - and 2 have a target-specific mode. - - The instruction must not read or write beyond the last byte of the - bit-field. - -'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 - 'word_mode'. Operand 1 may have mode 'byte_mode' or 'word_mode'; - often 'word_mode' is allowed only for registers. Operands 2 and 3 - must be valid for '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. - - This pattern is deprecated; please use 'extvM' and 'extvmisalignM' - instead. - -'extzv' - Like 'extv' except that the bit-field value is zero-extended. - - This pattern is deprecated; please use 'extzvM' and - 'extzvmisalignM' instead. - -'insv' - Store operand 3 (which must be valid for '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 - 'byte_mode' or 'word_mode'; often 'word_mode' is allowed only for - registers. Operands 1 and 2 must be valid for '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. - - This pattern is deprecated; please use 'insvM' and 'insvmisalignM' - instead. - -'movMODEcc' - 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. - -'addMODEcc' - Similar to 'movMODEcc' 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 false, - operand 2 is moved into operand 0, otherwise (operand 2 + operand - 3) is moved. - -'cstoreMODE4' - Store zero or nonzero in operand 0 according to whether a - comparison is true. Operand 1 is a comparison operator. Operand 2 - and operand 3 are the first and second operand of the comparison, - respectively. You specify the mode that operand 0 must have when - you write the '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 'STORE_FLAG_VALUE' (*note Misc::). If a description - cannot be found that can be used for all the possible comparison - operators, you should pick one and use a 'define_expand' to map all - results onto the one you chose. - - 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 restrict the predicates to not - allow these operands. Likewise if a given comparison operator will - always fail, independent of the operands (for floating-point modes, - the 'ordered_comparison_operator' predicate is often useful in this - case). - - If this pattern is omitted, the compiler will generate a - conditional branch--for example, it may copy a constant one to the - target and branching around an assignment of zero to the target--or - a libcall. If the predicate for operand 1 only rejects some - operators, it will also try reordering the operands and/or - inverting the result value (e.g. by an exclusive OR). These - possibilities could be cheaper or equivalent to the instructions - used for the 'cstoreMODE4' pattern followed by those required to - convert a positive result from 'STORE_FLAG_VALUE' to 1; in this - case, you can and should make operand 1's predicate reject some - operators in the 'cstoreMODE4' pattern, or remove the pattern - altogether from the machine description. - -'cbranchMODE4' - 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 'label_ref' that refers to the label to jump to. - -'jump' - A jump inside a function; an unconditional branch. Operand 0 is - the 'label_ref' of the label to jump to. This pattern name is - mandatory on all machines. - -'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 '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 'mem' RTX whose address is the address of the - function. Note, however, that this address can be a '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 - 'define_expand' (*note Expander Definitions::) that places the - address into a register and uses that register in the call - instruction. - -'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 'call' instruction - (but with numbers increased by one). - - Subroutines that return 'BLKmode' objects use the 'call' insn. - -'call_pop', 'call_value_pop' - Similar to 'call' and 'call_value', except used if defined and if - 'RETURN_POPS_ARGS' is nonzero. They should emit a 'parallel' that - contains both the function call and a 'set' to indicate the - adjustment made to the frame pointer. - - For machines where '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. - -'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 - 'parallel' expression where each element is a 'set' expression that - indicates the saving of a function return value into the result - block. - - This instruction pattern should be defined to support - '__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. - 'FUNCTION_VALUE_REGNO_P' is true for more than one register). - -'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 'movM' 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. - - It is valid for this pattern to expand to an instruction using - 'simple_return' if no epilogue is required. - -'simple_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 on a path where no epilogue is - required. This pattern is very similar to the 'return' instruction - pattern, but it is emitted only by the shrink-wrapping optimization - on paths where the function prologue has not been executed, and a - function return should occur without any of the effects of the - epilogue. Additional uses may be introduced on paths where both - the prologue and the epilogue have executed. - - For such machines, the condition specified in this pattern should - only be true when 'reload_completed' is nonzero and the function's - epilogue would only be a single instruction. For machines with - register windows, the routine '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 - - (define_insn "" - [(set (pc) - (if_then_else (match_operator - 0 "comparison_operator" - [(cc0) (const_int 0)]) - (return) - (pc)))] - "CONDITION" - "...") - - where CONDITION would normally be the same condition specified on - the named 'return' pattern. - -'untyped_return' - Untyped subroutine return instruction. This instruction pattern - should be defined to support '__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 '__builtin_apply' is stored; operand 1 is a - 'parallel' expression where each element is a 'set' expression that - indicates the restoring of a function return value from the result - block. - -'nop' - No-op instruction. This instruction pattern name should always be - defined to output a no-op in assembler code. '(const_int 0)' will - do as an RTL pattern. - -'indirect_jump' - An instruction to jump to an address which is operand zero. This - pattern name is mandatory on all machines. - -'casesi' - Instruction to jump through a dispatch table, including bounds - checking. This instruction takes five operands: - - 1. The index to dispatch on, which has mode 'SImode'. - - 2. The lower bound for indices in the table, an integer constant. - - 3. The total range of indices in the table--the largest index - minus the smallest one (both inclusive). - - 4. A label that precedes the table itself. - - 5. A label to jump to if the index has a value outside the - bounds. - - The table is an 'addr_vec' or 'addr_diff_vec' inside of a - 'jump_table_data'. The number of elements in the table is one plus - the difference between the upper bound and the lower bound. - -'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 'casesi' pattern. - - This pattern requires two operands: the address or offset, and a - label which should immediately precede the jump table. If the - macro '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 'Pmode'. - - The '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. - -'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. *Note 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. - -'doloop_end' - 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. *Note 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. The target hook - 'TARGET_CAN_USE_DOLOOP_P' controls the conditions under which - low-overhead loops can be used. - -'doloop_begin' - Companion instruction to 'doloop_end' required for machines that - need to perform some initialization, such as loading a special - counter register. Operand 1 is the associated 'doloop_end' pattern - and operand 0 is the register that it decrements. - - If initialization insns do not always need to be emitted, use a - 'define_expand' (*note Expander Definitions::) and make it fail. - -'canonicalize_funcptr_for_compare' - Canonicalize the function pointer in operand 1 and store the result - into operand 0. - - Operand 0 is always a 'reg' and has mode 'Pmode'; operand 1 may be - a 'reg', 'mem', 'symbol_ref', 'const_int', etc and also has mode - '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. - -'save_stack_block' -'save_stack_function' -'save_stack_nonlocal' -'restore_stack_block' -'restore_stack_function' -'restore_stack_nonlocal' - Most machines save and restore the stack pointer by copying it to - or from an object of mode '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 'define_expand' (*note Expander - Definitions::) that produces the required insns. The three types - of saves and restores are: - - 1. 'save_stack_block' saves the stack pointer at the start of a - block that allocates a variable-sized object, and - 'restore_stack_block' restores the stack pointer when the - block is exited. - - 2. 'save_stack_function' and '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 - 'alloca'. Only the epilogue uses the restored stack pointer, - allowing a simpler save or restore sequence on some machines. - - 3. '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 - '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. - - 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 'Pmode' but you can override that choice by - defining the 'STACK_SAVEAREA_MODE' macro (*note Storage Layout::). - You must specify an integral mode, or '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 'save_stack_block' is defined, operand 0 - must not be 'VOIDmode' since these saves can be arbitrarily nested. - - A save area is a 'mem' that is at a constant offset from - 'virtual_stack_vars_rtx' when the stack pointer is saved for use by - nonlocal gotos and a 'reg' in the other two cases. - -'allocate_stack' - Subtract (or add if '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 '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. - -'check_stack' - If stack checking (*note Stack Checking::) cannot be done on your - system by probing the stack, define this pattern to perform the - needed check and signal an error if the stack has overflowed. The - single operand is the address in the stack farthest from the - current stack pointer that you need to validate. Normally, on - platforms where this pattern is needed, you would obtain the stack - limit from a global or thread-specific variable or register. - -'probe_stack_address' - If stack checking (*note Stack Checking::) can be done on your - system by probing the stack but without the need to actually access - it, define this pattern and signal an error if the stack has - overflowed. The single operand is the memory address in the stack - that needs to be probed. - -'probe_stack' - If stack checking (*note Stack Checking::) can be done on your - system by probing the stack but doing it with a "store zero" - instruction is not valid or optimal, define this pattern to do the - probing differently and signal an error if the stack has - overflowed. The single operand is the memory reference in the - stack that needs to be probed. - -'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 - '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. - -'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. - -'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. - -'builtin_setjmp_setup' - This pattern, if defined, contains additional code needed to - initialize the '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 'jmp_buf'. - Note that the buffer is five words long and that the first three - are normally used by the generic mechanism. - -'builtin_setjmp_receiver' - This pattern, if defined, contains code needed at the site of a - 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 transferred - control; this pattern may be emitted at a small offset from that - label. - -'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 'builtin_setjmp_setup'. The single argument is a - pointer to the 'jmp_buf'. - -'eh_return' - This pattern, if defined, affects the way '__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 - '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 'EH_RETURN_HANDLER_RTX'. Either - that macro or this pattern needs to be defined if call frame - exception handling is to be used. - -'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 - 'TARGET_ASM_FUNCTION_PROLOGUE' to emit assembly code for the - prologue. - - The 'prologue' pattern is particularly useful for targets which - perform instruction scheduling. - -'window_save' - This pattern, if defined, emits RTL for a register window save. It - should be defined if the target machine has register windows but - the window events are decoupled from calls to subroutines. The - canonical example is the SPARC architecture. - -'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 - 'TARGET_ASM_FUNCTION_EPILOGUE' to emit assembly code for the - epilogue. - - The 'epilogue' pattern is particularly useful for targets which - perform instruction scheduling or which have delay slots for their - return instruction. - -'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 'sibcall_epilogue' pattern must not clobber any arguments used - for parameter passing or any stack slots for arguments passed to - the current function. - -'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. - -'ctrapMM4' - Conditional trap instruction. Operand 0 is a piece of RTL which - performs a comparison, and operands 1 and 2 are the arms of the - comparison. Operand 3 is the trap code, an integer. - - A typical 'ctrap' pattern looks like - - (define_insn "ctrapsi4" - [(trap_if (match_operator 0 "trap_operator" - [(match_operand 1 "register_operand") - (match_operand 2 "immediate_operand")]) - (match_operand 3 "const_int_operand" "i"))] - "" - "...") - -'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. - -'blockage' - - This pattern defines a pseudo insn that prevents the instruction - scheduler and other passes from moving instructions and using - register equivalences across the boundary defined by the blockage - insn. This needs to be an UNSPEC_VOLATILE pattern or a volatile - ASM. - -'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. - -'sync_compare_and_swapMODE' - - 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. - - For targets where the success or failure of the compare-and-swap - operation is available via the status flags, it is possible to - avoid a separate compare operation and issue the subsequent branch - or store-flag operation immediately after the compare-and-swap. To - this end, GCC will look for a 'MODE_CC' set in the output of - 'sync_compare_and_swapMODE'; if the machine description includes - such a set, the target should also define special 'cbranchcc4' - and/or 'cstorecc4' instructions. GCC will then be able to take the - destination of the 'MODE_CC' set and pass it to the 'cbranchcc4' or - 'cstorecc4' pattern as the first operand of the comparison (the - second will be '(const_int 0)'). - - For targets where the operating system may provide support for this - operation via library calls, the 'sync_compare_and_swap_optab' may - be initialized to a function with the same interface as the - '__sync_val_compare_and_swap_N' built-in. If the entire set of - __SYNC builtins are supported via library calls, the target can - initialize all of the optabs at once with 'init_sync_libfuncs'. - For the purposes of C++11 'std::atomic::is_lock_free', it is - assumed that these library calls do _not_ use any kind of - interruptable locking. - -'sync_addMODE', 'sync_subMODE' -'sync_iorMODE', 'sync_andMODE' -'sync_xorMODE', 'sync_nandMODE' - - 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. - - 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. - -'sync_old_addMODE', 'sync_old_subMODE' -'sync_old_iorMODE', 'sync_old_andMODE' -'sync_old_xorMODE', 'sync_old_nandMODE' - - These patterns 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. - -'sync_new_addMODE', 'sync_new_subMODE' -'sync_new_iorMODE', 'sync_new_andMODE' -'sync_new_xorMODE', 'sync_new_nandMODE' - - These patterns are like their 'sync_old_OP' counterparts, except - that they return the value that exists in the memory location after - the operation, rather than before the operation. - -'sync_lock_test_and_setMODE' - - 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 '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. - -'sync_lock_releaseMODE' - - This pattern, if defined, releases a lock set by - 'sync_lock_test_and_setMODE'. 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 - 'sync_lock_test_and_setMODE', any value operand which is not the - constant 0 should be rejected with '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 'memory_barrier' pattern - will be emitted, followed by a store of the value to the memory - operand. - -'atomic_compare_and_swapMODE' - This pattern, if defined, emits code for an atomic compare-and-swap - operation with memory model semantics. Operand 2 is the memory on - which the atomic operation is performed. Operand 0 is an output - operand which is set to true or false based on whether the - operation succeeded. Operand 1 is an output operand which is set - to the contents of the memory before the operation was attempted. - Operand 3 is the value that is expected to be in memory. Operand 4 - is the value to put in memory if the expected value is found there. - Operand 5 is set to 1 if this compare and swap is to be treated as - a weak operation. Operand 6 is the memory model to be used if the - operation is a success. Operand 7 is the memory model to be used - if the operation fails. - - If memory referred to in operand 2 contains the value in operand 3, - then operand 4 is stored in memory pointed to by operand 2 and - fencing based on the memory model in operand 6 is issued. - - If memory referred to in operand 2 does not contain the value in - operand 3, then fencing based on the memory model in operand 7 is - issued. - - If a target does not support weak compare-and-swap operations, or - the port elects not to implement weak operations, the argument in - operand 5 can be ignored. Note a strong implementation must be - provided. - - If this pattern is not provided, the '__atomic_compare_exchange' - built-in functions will utilize the legacy 'sync_compare_and_swap' - pattern with an '__ATOMIC_SEQ_CST' memory model. - -'atomic_loadMODE' - This pattern implements an atomic load operation with memory model - semantics. Operand 1 is the memory address being loaded from. - Operand 0 is the result of the load. Operand 2 is the memory model - to be used for the load operation. - - If not present, the '__atomic_load' built-in function will either - resort to a normal load with memory barriers, or a compare-and-swap - operation if a normal load would not be atomic. - -'atomic_storeMODE' - This pattern implements an atomic store operation with memory model - semantics. Operand 0 is the memory address being stored to. - Operand 1 is the value to be written. Operand 2 is the memory - model to be used for the operation. - - If not present, the '__atomic_store' built-in function will attempt - to perform a normal store and surround it with any required memory - fences. If the store would not be atomic, then an - '__atomic_exchange' is attempted with the result being ignored. - -'atomic_exchangeMODE' - This pattern implements an atomic exchange operation with memory - model semantics. Operand 1 is the memory location the operation is - performed on. Operand 0 is an output operand which is set to the - original value contained in the memory pointed to by operand 1. - Operand 2 is the value to be stored. Operand 3 is the memory model - to be used. - - If this pattern is not present, the built-in function - '__atomic_exchange' will attempt to preform the operation with a - compare and swap loop. - -'atomic_addMODE', 'atomic_subMODE' -'atomic_orMODE', 'atomic_andMODE' -'atomic_xorMODE', 'atomic_nandMODE' - - These patterns emit code for an atomic operation on memory with - memory model semantics. Operand 0 is the memory on which the - atomic operation is performed. Operand 1 is the second operand to - the binary operator. Operand 2 is the memory model to be used by - the operation. - - If these patterns are not defined, attempts will be made to use - legacy 'sync' patterns, or equivalent patterns which return a - result. If none of these are available a compare-and-swap loop - will be used. - -'atomic_fetch_addMODE', 'atomic_fetch_subMODE' -'atomic_fetch_orMODE', 'atomic_fetch_andMODE' -'atomic_fetch_xorMODE', 'atomic_fetch_nandMODE' - - These patterns emit code for an atomic operation on memory with - memory model semantics, and return the original value. Operand 0 - is an output operand which contains the value of the memory - location before the operation was performed. Operand 1 is the - memory on which the atomic operation is performed. Operand 2 is - the second operand to the binary operator. Operand 3 is the memory - model to be used by the operation. - - If these patterns are not defined, attempts will be made to use - legacy 'sync' patterns. If none of these are available a - compare-and-swap loop will be used. - -'atomic_add_fetchMODE', 'atomic_sub_fetchMODE' -'atomic_or_fetchMODE', 'atomic_and_fetchMODE' -'atomic_xor_fetchMODE', 'atomic_nand_fetchMODE' - - These patterns emit code for an atomic operation on memory with - memory model semantics and return the result after the operation is - performed. Operand 0 is an output operand which contains the value - after the operation. Operand 1 is the memory on which the atomic - operation is performed. Operand 2 is the second operand to the - binary operator. Operand 3 is the memory model to be used by the - operation. - - If these patterns are not defined, attempts will be made to use - legacy 'sync' patterns, or equivalent patterns which return the - result before the operation followed by the arithmetic operation - required to produce the result. If none of these are available a - compare-and-swap loop will be used. - -'atomic_test_and_set' - - This pattern emits code for '__builtin_atomic_test_and_set'. - Operand 0 is an output operand which is set to true if the previous - previous contents of the byte was "set", and false otherwise. - Operand 1 is the 'QImode' memory to be modified. Operand 2 is the - memory model to be used. - - The specific value that defines "set" is implementation defined, - and is normally based on what is performed by the native atomic - test and set instruction. - -'mem_thread_fenceMODE' - This pattern emits code required to implement a thread fence with - memory model semantics. Operand 0 is the memory model to be used. - - If this pattern is not specified, all memory models except - '__ATOMIC_RELAXED' will result in issuing a 'sync_synchronize' - barrier pattern. - -'mem_signal_fenceMODE' - This pattern emits code required to implement a signal fence with - memory model semantics. Operand 0 is the memory model to be used. - - This pattern should impact the compiler optimizers the same way - that mem_signal_fence does, but it does not need to issue any - barrier instructions. - - If this pattern is not specified, all memory models except - '__ATOMIC_RELAXED' will result in issuing a 'sync_synchronize' - barrier pattern. - -'get_thread_pointerMODE' -'set_thread_pointerMODE' - These patterns emit code that reads/sets the TLS thread pointer. - Currently, these are only needed if the target needs to support the - '__builtin_thread_pointer' and '__builtin_set_thread_pointer' - builtins. - - The get/set patterns have a single output/input operand - respectively, with MODE intended to be 'Pmode'. - -'stack_protect_set' - - This pattern, if defined, moves a 'ptr_mode' 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. - -'stack_protect_test' - - This pattern, if defined, compares a 'ptr_mode' 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 were equal. - - If this pattern is not defined, then a plain compare pattern and - conditional branch pattern is used. - -'clear_cache' - - This pattern, if defined, flushes the instruction cache for a - region of memory. The region is bounded to by the Pmode pointers - in operand 0 inclusive and operand 1 exclusive. - - If this pattern is not defined, a call to the library function - '__clear_cache' is used. - - -File: gccint.info, Node: Pattern Ordering, Next: Dependent Patterns, Prev: Standard Names, Up: Machine Desc - -16.10 When the Order of Patterns Matters -======================================== - -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. - - -File: gccint.info, Node: Dependent Patterns, Next: Jump Patterns, Prev: Pattern Ordering, Up: Machine Desc - -16.11 Interdependence of Patterns -================================= - -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 - - (set (match_operand:SI 0 ...) - (extend:SI (match_operand:HI 1 ...))) - - (set (match_operand:SI 0 ...) - (extend:SI (match_operand:QI 1 ...))) - -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 -('HImode', here). If the pattern matches the '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. - - -File: gccint.info, Node: Jump Patterns, Next: Looping Patterns, Prev: Dependent Patterns, Up: Machine Desc - -16.12 Defining Jump Instruction Patterns -======================================== - -GCC does not assume anything about how the machine realizes jumps. The -machine description should define a single pattern, usually a -'define_expand', which expands to all the required insns. - - Usually, this would be a comparison insn to set the condition code and -a separate branch insn testing the condition code and branching or not -according to its value. For many machines, however, separating compares -and branches is limiting, which is why the more flexible approach with -one 'define_expand' is used in GCC. The machine description becomes -clearer for architectures that have compare-and-branch instructions but -no condition code. It also works better when different sets of -comparison operators are supported by different kinds of conditional -branches (e.g. integer vs. floating-point), or by conditional branches -with respect to conditional stores. - - Two separate insns are always used if the machine description -represents a condition code register using the legacy RTL expression -'(cc0)', and on most machines that use a separate condition code -register (*note Condition Code::). For machines that use '(cc0)', in -fact, the set and use of the condition code must be separate and -adjacent(1), thus allowing flags in 'cc_status' to be used (*note -Condition Code::) and so that the comparison and branch insns could be -located from each other by using the functions 'prev_cc0_setter' and -'next_cc0_user'. - - Even in this case having a single entry point for conditional branches -is advantageous, because it handles equally well the case where a single -comparison instruction records the results of both signed and unsigned -comparison of the given operands (with the branch insns coming in -distinct signed and unsigned flavors) as in the x86 or SPARC, and the -case where there are distinct signed and unsigned compare instructions -and only one set of conditional branch instructions as in the PowerPC. - - ---------- Footnotes ---------- - - (1) 'note' insns can separate them, though. - - -File: gccint.info, Node: Looping Patterns, Next: Insn Canonicalizations, Prev: Jump Patterns, Up: Machine Desc - -16.13 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 '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 -'dbra'-like instruction and avoids pipeline stalls associated with the -jump. - - GCC has three special named patterns to support low overhead looping. -They are 'decrement_and_branch_until_zero', 'doloop_begin', and -'doloop_end'. The first pattern, '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 '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 'dbra' instruction: - - (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)" - "...") - - 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 -1. Note that the following similar -pattern will not be matched by the combiner. - - (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)" - "...") - - The other two special looping patterns, 'doloop_begin' and -'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 'doloop_end' pattern describes the actual looping instruction (or -the implicit looping operation) and the '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 'doloop' insn is -emitted at the end of the loop. The machine dependent reorg pass checks -for the presence of this '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 'decrement_and_branch_until_zero' -and the '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. - - -File: gccint.info, Node: Insn Canonicalizations, Next: Expander Definitions, Prev: Looping Patterns, Up: Machine Desc - -16.14 Canonicalization of Instructions -====================================== - -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: - - * 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. - - * For associative operators, a sequence of operators will always - chain to the left; for instance, only the left operand of an - integer 'plus' can itself be a 'plus'. 'and', 'ior', 'xor', - 'plus', 'mult', 'smin', 'smax', 'umin', and 'umax' are associative - when applied to integers, and sometimes to floating-point. - - * For these operators, if only one operand is a 'neg', 'not', 'mult', - 'plus', or 'minus' expression, it will be the first operand. - - * In combinations of 'neg', 'mult', 'plus', and 'minus', the 'neg' - operations (if any) will be moved inside the operations as far as - possible. For instance, '(neg (mult A B))' is canonicalized as - '(mult (neg A) B)', but '(plus (mult (neg B) C) A)' is - canonicalized as '(minus A (mult B C))'. - - * For the 'compare' operator, a constant is always the second operand - if the first argument is a condition code register or '(cc0)'. - - * An operand of 'neg', 'not', 'mult', 'plus', or 'minus' is made the - first operand under the same conditions as above. - - * '(ltu (plus A B) B)' is converted to '(ltu (plus A B) A)'. - Likewise with 'geu' instead of 'ltu'. - - * '(minus X (const_int N))' is converted to '(plus X (const_int - -N))'. - - * Within address computations (i.e., inside 'mem'), a left shift is - converted into the appropriate multiplication by a power of two. - - * 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 '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 - - (define_insn "" - [(set (match_operand:M 0 ...) - (and:M (not:M (match_operand:M 1 ...)) - (match_operand:M 2 ...)))] - "..." - "...") - - Similarly, a pattern for a "NAND" instruction should be written - - (define_insn "" - [(set (match_operand:M 0 ...) - (ior:M (not:M (match_operand:M 1 ...)) - (not:M (match_operand:M 2 ...))))] - "..." - "...") - - In both cases, it is not necessary to include patterns for the many - logically equivalent RTL expressions. - - * The only possible RTL expressions involving both bitwise - exclusive-or and bitwise negation are '(xor:M X Y)' and '(not:M - (xor:M X Y))'. - - * The sum of three items, one of which is a constant, will only - appear in the form - - (plus:M (plus:M X Y) CONSTANT) - - * Equality comparisons of a group of bits (usually a single bit) with - zero will be written using 'zero_extract' rather than the - equivalent 'and' or 'sign_extract' operations. - - * '(sign_extend:M1 (mult:M2 (sign_extend:M2 X) (sign_extend:M2 Y)))' - is converted to '(mult:M1 (sign_extend:M1 X) (sign_extend:M1 Y))', - and likewise for 'zero_extend'. - - * '(sign_extend:M1 (mult:M2 (ashiftrt:M2 X S) (sign_extend:M2 Y)))' - is converted to '(mult:M1 (sign_extend:M1 (ashiftrt:M2 X S)) - (sign_extend:M1 Y))', and likewise for patterns using 'zero_extend' - and 'lshiftrt'. If the second operand of 'mult' is also a shift, - then that is extended also. This transformation is only applied - when it can be proven that the original operation had sufficient - precision to prevent overflow. - - Further canonicalization rules are defined in the function -'commutative_operand_precedence' in 'gcc/rtlanal.c'. - - -File: gccint.info, Node: Expander Definitions, Next: Insn Splitting, Prev: Insn Canonicalizations, Up: Machine Desc - -16.15 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 -'define_expand' to specify how to generate the sequence of RTL. - - A 'define_expand' is an RTL expression that looks almost like a -'define_insn'; but, unlike the latter, a 'define_expand' is used only -for RTL generation and it can produce more than one RTL insn. - - A 'define_expand' RTX has four operands: - - * The name. Each 'define_expand' must have a name, since the only - use for it is to refer to it by name. - - * The RTL template. This is a vector of RTL expressions representing - a sequence of separate instructions. Unlike 'define_insn', there - is no implicit surrounding 'PARALLEL'. - - * 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 '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. - - * 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 'emit_insn', etc. - Any such insns precede the ones that come from the RTL template. - - * Optionally, a vector containing the values of attributes. *Note - Insn Attributes::. - - Every RTL insn emitted by a 'define_expand' must match some -'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 '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 '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 -'define_expand'. Internal operands are substituted into the RTL -template with 'match_dup', never with '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 'operands' so -that 'match_dup' can find them. - - There are two special macros defined for use in the preparation -statements: 'DONE' and 'FAIL'. Use them with a following semicolon, as -a statement. - -'DONE' - Use the '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 'emit_insn' within the - preparation statements; the RTL template will not be generated. - -'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 ('extv', 'extzv', - and 'insv') operations. - - If the preparation falls through (invokes neither 'DONE' nor 'FAIL'), -then the 'define_expand' acts like a '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 'DONE' -or 'FAIL', the RTL template may be reduced to a simple list of operands, -such as this example: - - (define_expand "addsi3" - [(match_operand:SI 0 "register_operand" "") - (match_operand:SI 1 "register_operand" "") - (match_operand:SI 2 "register_operand" "")] - "" - " - { - handle_add (operands[0], operands[1], operands[2]); - DONE; - }") - - Here is an example, the definition of left-shift for the SPUR chip: - - (define_expand "ashlsi3" - [(set (match_operand:SI 0 "register_operand" "") - (ashift:SI - (match_operand:SI 1 "register_operand" "") - (match_operand:SI 2 "nonmemory_operand" "")))] - "" - " - - { - if (GET_CODE (operands[2]) != CONST_INT - || (unsigned) INTVAL (operands[2]) > 3) - FAIL; - }") - -This example uses '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 'define_insn' in -that case. Here is another case (zero-extension on the 68000) which -makes more use of the power of 'define_expand': - - (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]);") - -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 'make_safe_from' copies the 'operands[1]' into a -temporary register if it refers to '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 'and'-ing the result against -a halfword mask. But this mask cannot be represented by a 'const_int' -because the constant value is too large to be legitimate on this -machine. So it must be copied into a register with 'force_reg' and then -the register used in the 'and'. - - (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)); ") - - _Note:_ If the '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_label', 'barrier' or 'note'. It must -be an 'insn', 'jump_insn' or '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. - - -File: gccint.info, Node: Insn Splitting, Next: Including Patterns, Prev: Expander Definitions, Up: Machine Desc - -16.16 Defining How to Split 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 (*note Delay Slots::) or that have instructions whose output is -not available for multiple cycles (*note 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 '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. - - The 'define_split' definition tells the compiler how to split a complex -insn into several simpler insns. It looks like this: - - (define_split - [INSN-PATTERN] - "CONDITION" - [NEW-INSN-PATTERN-1 - NEW-INSN-PATTERN-2 - ...] - "PREPARATION-STATEMENTS") - - INSN-PATTERN is a pattern that needs to be split and CONDITION is the -final condition to be tested, as in a 'define_insn'. When an insn -matching INSN-PATTERN and satisfying CONDITION is found, it is replaced -in the insn list with the insns given by NEW-INSN-PATTERN-1, -NEW-INSN-PATTERN-2, etc. - - The PREPARATION-STATEMENTS are similar to those statements that are -specified for 'define_expand' (*note 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 -'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 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 'define_insn' and, if -'reload_completed' is nonzero, is known to satisfy the constraints of -that 'define_insn'. In that case, the new insn patterns must also be -insns that are matched by some 'define_insn' and, if 'reload_completed' -is nonzero, must also satisfy the constraints of those definitions. - - As an example of this usage of 'define_split', consider the following -example from 'a29k.md', which splits a 'sign_extend' from 'HImode' to -'SImode' into a pair of shift insns: - - (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]); }") - - When the combiner phase tries to split an insn pattern, it is always -the case that the pattern is _not_ matched by any 'define_insn'. The -combiner pass first tries to split a single 'set' expression and then -the same 'set' expression inside a 'parallel', but followed by a -'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 'define_insn' definitions, so -you need not do this test in the 'define_split' (of course, there is no -point in writing a 'define_split' that will never produce insns that -match). - - Here is an example of this use of 'define_split', taken from -'rs6000.md': - - (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); - }") - - Here the predicate 'non_add_cint_operand' matches any 'const_int' that -is _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: - - (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)))] - " - { - /* 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); - }") - - To avoid confusion, don't write a single 'define_split' that accepts -some insns that match some 'define_insn' as well as some insns that -don't. Instead, write two separate '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 'REG_BR_PROB' note to each conditional -jump. A global variable 'split_branch_probability' holds the -probability of the original branch in case it was a simple conditional -jump, -1 otherwise. To simplify recomputing of edge frequencies, the -new sequence is required to have only forward jumps to the newly created -labels. - - For the common case where the pattern of a define_split exactly matches -the pattern of a define_insn, use 'define_insn_and_split'. It looks -like this: - - (define_insn_and_split - [INSN-PATTERN] - "CONDITION" - "OUTPUT-TEMPLATE" - "SPLIT-CONDITION" - [NEW-INSN-PATTERN-1 - NEW-INSN-PATTERN-2 - ...] - "PREPARATION-STATEMENTS" - [INSN-ATTRIBUTES]) - - INSN-PATTERN, CONDITION, OUTPUT-TEMPLATE, and INSN-ATTRIBUTES are used -as in 'define_insn'. The NEW-INSN-PATTERN vector and the -PREPARATION-STATEMENTS are used as in a 'define_split'. The -SPLIT-CONDITION is also used as in 'define_split', with the additional -behavior that if the condition starts with '&&', 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: - - (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")]) - - In this case, the actual split condition will be -'TARGET_ZERO_EXTEND_WITH_AND && !optimize_size && reload_completed'. - - The 'define_insn_and_split' construction provides exactly the same -functionality as two separate 'define_insn' and 'define_split' patterns. -It exists for compactness, and as a maintenance tool to prevent having -to ensure the two patterns' templates match. - - -File: gccint.info, Node: Including Patterns, Next: Peephole Definitions, Prev: Insn Splitting, Up: Machine Desc - -16.17 Including Patterns in Machine Descriptions. -================================================= - -The 'include' pattern tells the compiler tools where to look for -patterns that are in files other than in the file '.md'. This is used -only at build time and there is no preprocessing allowed. - - It looks like: - - - (include - PATHNAME) - - For example: - - - (include "filestuff") - - Where PATHNAME is a string that specifies the location of the file, -specifies the include file to be in 'gcc/config/target/filestuff'. The -directory '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: - - - (include "BOGUS/filestuff") - - the include file is specified to be in -'gcc/config/TARGET/BOGUS/filestuff'. - - Specifying an absolute path for the include file such as; - - (include "/u2/BOGUS/filestuff") - - is permitted but is not encouraged. - -16.17.1 RTL Generation Tool Options for Directory Search --------------------------------------------------------- - -The '-IDIR' option specifies directories to search for machine -descriptions. For example: - - - genrecog -I/p1/abc/proc1 -I/p2/abcd/pro2 target.md - - Add the directory 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 '-I' option, the directories are -scanned in left-to-right order; the standard default directory come -after. - - -File: gccint.info, Node: Peephole Definitions, Next: Insn Attributes, Prev: Including Patterns, Up: Machine Desc - -16.18 Machine-Specific Peephole Optimizers -========================================== - -In addition to instruction patterns the '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 'define_peephole' is run at assembly output time to match insns -and substitute assembly text. Use of 'define_peephole' is deprecated. - - A newer 'define_peephole2' matches insns and substitutes new insns. -The '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 - - -File: gccint.info, Node: define_peephole, Next: define_peephole2, Up: Peephole Definitions - -16.18.1 RTL to Text Peephole Optimizers ---------------------------------------- - -A definition looks like this: - - (define_peephole - [INSN-PATTERN-1 - INSN-PATTERN-2 - ...] - "CONDITION" - "TEMPLATE" - "OPTIONAL-INSN-ATTRIBUTES") - -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 'define_insn'. - - In this skeleton, INSN-PATTERN-1 and so on are patterns to match -consecutive insns. The optimization applies to a sequence of insns when -INSN-PATTERN-1 matches the first one, INSN-PATTERN-2 matches the next, -and so on. - - Each of the insns matched by a peephole must also match a -'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 '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 'match_operands', -'match_operator', and '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 -'match_operand' in one insn and 'match_dup' in the other. - - The operand constraints used in '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 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 -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. - - The way to refer to the operands in CONDITION is to write 'operands[I]' -for operand number I (as matched by '(match_operand I ...)'). Use the -variable 'insn' to refer to the last of the insns being matched; use -'prev_active_insn' to find the preceding insns. - - When optimizing computations with intermediate results, you can use -CONDITION to match only when the intermediate results are not used -elsewhere. Use the C expression 'dead_or_set_p (INSN, OP)', where INSN -is the insn in which you expect the value to be used for the last time -(from the value of 'insn', together with use of 'prev_nonnote_insn'), -and OP is the intermediate value (from 'operands[I]'). - - Applying the optimization means replacing the sequence of insns with -one new insn. The TEMPLATE controls ultimate output of assembler code -for this combined insn. It works exactly like the template of a -'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: - - (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 - }) - - The effect of this optimization is to change - - jbsr _foobar - addql #4,sp - movel d1,sp@- - movel d0,sp@- - fmoved sp@+,fp0 - -into - - jbsr _foobar - movel d1,sp@ - movel d0,sp@- - fmoved sp@+,fp0 - - INSN-PATTERN-1 and so on look _almost_ like the second operand of -'define_insn'. There is one important difference: the second operand of -'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 'define_peephole'. But when there are multiple actions in -a 'define_insn', they are implicitly enclosed in a 'parallel'. Then you -must explicitly write the 'parallel', and the square brackets within it, -in the 'define_peephole'. Thus, if an insn pattern looks like this, - - (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") - -then the way to mention this insn in a peephole is as follows: - - (define_peephole - [... - (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)))]) - ...] - ...) - - -File: gccint.info, Node: define_peephole2, Prev: define_peephole, Up: Peephole Definitions - -16.18.2 RTL to RTL Peephole Optimizers --------------------------------------- - -The '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. - - (define_peephole2 - [INSN-PATTERN-1 - INSN-PATTERN-2 - ...] - "CONDITION" - [NEW-INSN-PATTERN-1 - NEW-INSN-PATTERN-2 - ...] - "PREPARATION-STATEMENTS") - - The definition is almost identical to 'define_split' (*note 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. - - Scratch registers are requested with a '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 '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: - - (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))])] - "") - -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 'SImode' register of class 'GENERAL_REGS' ('"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: - - (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))] - "/* 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))] - "") - -If we had not added the '(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 'set'. - - -File: gccint.info, Node: Insn Attributes, Next: Conditional Execution, Prev: Peephole Definitions, Up: Machine Desc - -16.19 Instruction Attributes -============================ - -In addition to describing the instruction supported by the target -machine, the 'md' file also defines a group of "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 -'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. -* Mnemonic Attribute:: Obtain the instruction mnemonic as attribute value. -* Delay Slots:: Defining delay slots required for a machine. -* Processor pipeline description:: Specifying information for insn scheduling. - - -File: gccint.info, Node: Defining Attributes, Next: Expressions, Up: Insn Attributes - -16.19.1 Defining Attributes and their Values --------------------------------------------- - -The 'define_attr' expression is used to define each attribute required -by the target machine. It looks like: - - (define_attr NAME LIST-OF-VALUES DEFAULT) - - NAME is a string specifying the name of the attribute being defined. -Some attributes are used in a special way by the rest of the compiler. -The 'enabled' attribute can be used to conditionally enable or disable -insn alternatives (*note Disable Insn Alternatives::). The 'predicable' -attribute, together with a suitable 'define_cond_exec' (*note -Conditional Execution::), can be used to automatically generate -conditional variants of instruction patterns. The 'mnemonic' attribute -can be used to check for the instruction mnemonic (*note Mnemonic -Attribute::). The compiler internally uses the names 'ce_enabled' and -'nonce_enabled', so they should not be used elsewhere as alternative -names. - - 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. - - 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. *Note Attr Example::, for -more information on the handling of defaults. *Note Constant -Attributes::, for information on attributes that do not depend on any -particular insn. - - For each defined attribute, a number of definitions are written to the -'insn-attr.h' file. For cases where an explicit set of values is -specified for an attribute, the following are defined: - - * A '#define' is written for the symbol 'HAVE_ATTR_NAME'. - - * An enumerated class is defined for 'attr_NAME' with elements of the - form 'UPPER-NAME_UPPER-VALUE' where the attribute name and value - are first converted to uppercase. - - * A function 'get_attr_NAME' is defined that is passed an insn and - returns the attribute value for that insn. - - For example, if the following is present in the 'md' file: - - (define_attr "type" "branch,fp,load,store,arith" ...) - -the following lines will be written to the file 'insn-attr.h'. - - #define HAVE_ATTR_type 1 - enum attr_type {TYPE_BRANCH, TYPE_FP, TYPE_LOAD, - TYPE_STORE, TYPE_ARITH}; - extern enum attr_type get_attr_type (); - - If the attribute takes numeric values, no 'enum' type will be defined -and the function to obtain the attribute's value will return 'int'. - - There are attributes which are tied to a specific meaning. These -attributes are not free to use for other purposes: - -'length' - The 'length' attribute is used to calculate the length of emitted - code chunks. This is especially important when verifying branch - distances. *Note Insn Lengths::. - -'enabled' - The 'enabled' attribute can be defined to prevent certain - alternatives of an insn definition from being used during code - generation. *Note Disable Insn Alternatives::. - -'mnemonic' - The 'mnemonic' attribute can be defined to implement instruction - specific checks in e.g. the pipeline description. *Note Mnemonic - Attribute::. - - For each of these special attributes, the corresponding -'HAVE_ATTR_NAME' '#define' is also written when the attribute is not -defined; in that case, it is defined as '0'. - - Another way of defining an attribute is to use: - - (define_enum_attr "ATTR" "ENUM" DEFAULT) - - This works in just the same way as 'define_attr', except that the list -of values is taken from a separate enumeration called ENUM (*note -define_enum::). This form allows you to use the same list of values for -several attributes without having to repeat the list each time. For -example: - - (define_enum "processor" [ - model_a - model_b - ... - ]) - (define_enum_attr "arch" "processor" - (const (symbol_ref "target_arch"))) - (define_enum_attr "tune" "processor" - (const (symbol_ref "target_tune"))) - - defines the same attributes as: - - (define_attr "arch" "model_a,model_b,..." - (const (symbol_ref "target_arch"))) - (define_attr "tune" "model_a,model_b,..." - (const (symbol_ref "target_tune"))) - - but without duplicating the processor list. The second example defines -two separate C enums ('attr_arch' and 'attr_tune') whereas the first -defines a single C enum ('processor'). - - -File: gccint.info, Node: Expressions, Next: Tagging Insns, Prev: Defining Attributes, Up: Insn Attributes - -16.19.2 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: - -'(const_int I)' - The integer I specifies the value of a numeric attribute. I must - be non-negative. - - The value of a numeric attribute can be specified either with a - 'const_int', or as an integer represented as a string in - 'const_string', 'eq_attr' (see below), 'attr', 'symbol_ref', simple - arithmetic expressions, and 'set_attr' overrides on specific - instructions (*note Tagging Insns::). - -'(const_string VALUE)' - The string VALUE specifies a constant attribute value. If VALUE is - specified as '"*"', it means that the default value of the - attribute is to be used for the insn containing this expression. - '"*"' obviously cannot be used in the DEFAULT expression of a - 'define_attr'. - - If the attribute whose value is being specified is numeric, VALUE - must be a string containing a non-negative integer (normally - 'const_int' would be used in this case). Otherwise, it must - contain one of the valid values for the attribute. - -'(if_then_else TEST TRUE-VALUE FALSE-VALUE)' - TEST specifies an attribute test, whose format is defined below. - The value of this expression is TRUE-VALUE if TEST is true, - otherwise it is FALSE-VALUE. - -'(cond [TEST1 VALUE1 ...] DEFAULT)' - The first operand of this expression is a vector containing an even - number of expressions and consisting of pairs of TEST and VALUE - expressions. The value of the 'cond' expression is that of the - VALUE corresponding to the first true TEST expression. If none of - the TEST expressions are true, the value of the 'cond' expression - is that of the DEFAULT expression. - - TEST expressions can have one of the following forms: - -'(const_int I)' - This test is true if I is nonzero and false otherwise. - -'(not TEST)' -'(ior TEST1 TEST2)' -'(and TEST1 TEST2)' - These tests are true if the indicated logical function is true. - -'(match_operand:M N PRED CONSTRAINTS)' - This test is true if operand N of the insn whose attribute value is - being determined has mode M (this part of the test is ignored if M - is 'VOIDmode') and the function specified by the string PRED - returns a nonzero value when passed operand N and mode M (this part - of the test is ignored if PRED is the null string). - - The CONSTRAINTS operand is ignored and should be the null string. - -'(match_test C-EXPR)' - The test is true if C expression C-EXPR is true. In non-constant - attributes, C-EXPR has access to the following variables: - - INSN - The rtl instruction under test. - WHICH_ALTERNATIVE - The 'define_insn' alternative that INSN matches. *Note Output - Statement::. - OPERANDS - An array of INSN's rtl operands. - - C-EXPR behaves like the condition in a C 'if' statement, so there - is no need to explicitly convert the expression into a boolean 0 or - 1 value. For example, the following two tests are equivalent: - - (match_test "x & 2") - (match_test "(x & 2) != 0") - -'(le ARITH1 ARITH2)' -'(leu ARITH1 ARITH2)' -'(lt ARITH1 ARITH2)' -'(ltu ARITH1 ARITH2)' -'(gt ARITH1 ARITH2)' -'(gtu ARITH1 ARITH2)' -'(ge ARITH1 ARITH2)' -'(geu ARITH1 ARITH2)' -'(ne ARITH1 ARITH2)' -'(eq ARITH1 ARITH2)' - These tests are true if the indicated comparison of the two - arithmetic expressions is true. Arithmetic expressions are formed - with 'plus', 'minus', 'mult', 'div', 'mod', 'abs', 'neg', 'and', - 'ior', 'xor', 'not', 'ashift', 'lshiftrt', and 'ashiftrt' - expressions. - - 'const_int' and 'symbol_ref' are always valid terms (*note Insn - Lengths::,for additional forms). 'symbol_ref' is a string denoting - a C expression that yields an 'int' when evaluated by the - 'get_attr_...' routine. It should normally be a global variable. - -'(eq_attr NAME VALUE)' - NAME is a string specifying the name of an attribute. - - VALUE is a string that is either a valid value for attribute NAME, - a comma-separated list of values, or '!' followed by a value or - list. If VALUE does not begin with a '!', this test is true if the - value of the NAME attribute of the current insn is in the list - specified by VALUE. If VALUE begins with a '!', this test is true - if the attribute's value is _not_ in the specified list. - - For example, - - (eq_attr "type" "load,store") - - is equivalent to - - (ior (eq_attr "type" "load") (eq_attr "type" "store")) - - If NAME specifies an attribute of 'alternative', it refers to the - value of the compiler variable 'which_alternative' (*note Output - Statement::) and the values must be small integers. For example, - - (eq_attr "alternative" "2,3") - - is equivalent to - - (ior (eq (symbol_ref "which_alternative") (const_int 2)) - (eq (symbol_ref "which_alternative") (const_int 3))) - - Note that, for most attributes, an '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. - -'(attr_flag NAME)' - The value of an 'attr_flag' expression is true if the flag - specified by NAME is true for the 'insn' currently being scheduled. - - NAME is a string specifying one of a fixed set of flags to test. - Test the flags 'forward' and 'backward' to determine the direction - of a conditional branch. - - 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). - - (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"))]) - - The 'forward' and 'backward' flags are false if the current 'insn' - being scheduled is not a conditional branch. - - 'attr_flag' is only used during delay slot scheduling and has no - meaning to other passes of the compiler. - -'(attr NAME)' - The value of another attribute is returned. This is most useful - for numeric attributes, as 'eq_attr' and 'attr_flag' produce more - efficient code for non-numeric attributes. - - -File: gccint.info, Node: Tagging Insns, Next: Attr Example, Prev: Expressions, Up: Insn Attributes - -16.19.3 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 'define_peephole' -generated it). Every 'define_insn' and '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 -'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 'define_insn' and '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 'set' expression whose first operand is an 'attr' expression -giving the name of the attribute being set. The second operand of the -'set' is an attribute expression (*note Expressions::) giving the value -of the attribute. - - When the attribute value depends on the 'alternative' attribute (i.e., -which is the applicable alternative in the constraint of the insn), the -'set_attr_alternative' expression can be used. It allows the -specification of a vector of attribute expressions, one for each -alternative. - - When the generality of arbitrary attribute expressions is not required, -the simpler '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, NAME is a string specifying the attribute to be set. - -'(set_attr NAME VALUE-STRING)' - 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 '*' for some alternative, in - which case the attribute will assume its default value for insns - matching that alternative. - -'(set_attr_alternative NAME [VALUE1 VALUE2 ...])' - Depending on the alternative of the insn, the value will be one of - the specified values. This is a shorthand for using a 'cond' with - tests on the 'alternative' attribute. - -'(set (attr NAME) VALUE)' - The first operand of this 'set' must be the special RTL expression - 'attr', whose sole operand is a string giving the name of the - attribute being set. VALUE is the value of the attribute. - - The following shows three different ways of representing the same -attribute value specification: - - (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"))) - - The 'define_asm_attributes' expression provides a mechanism to specify -the attributes assigned to insns produced from an 'asm' statement. It -has the form: - - (define_asm_attributes [ATTR-SETS]) - -where ATTR-SETS is specified the same as for both the 'define_insn' and -the '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 'length' attribute is handled specially. The way -to compute the length of an 'asm' insn is to multiply the length -specified in the expression 'define_asm_attributes' by the number of -machine instructions specified in the 'asm' statement, determined by -counting the number of semicolons and newlines in the string. -Therefore, the value of the 'length' attribute specified in a -'define_asm_attributes' should be the maximum possible length of a -single machine instruction. - - -File: gccint.info, Node: Attr Example, Next: Insn Lengths, Prev: Tagging Insns, Up: Insn Attributes - -16.19.4 Example of Attribute Specifications -------------------------------------------- - -The judicious use of defaulting is important in the efficient use of -insn attributes. Typically, insns are divided into "types" and an -attribute, customarily called '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 'md' file for such a machine: - - (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")]) - - 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. - - -File: gccint.info, Node: Insn Lengths, Next: Constant Attributes, Prev: Attr Example, Up: Insn Attributes - -16.19.5 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 'length' -attribute, is defined. This attribute must be defined to have numeric -values by specifying a null string in its 'define_attr'. - - In the case of the 'length' attribute, two additional forms of -arithmetic terms are allowed in test expressions: - -'(match_dup N)' - This refers to the address of operand N of the current insn, which - must be a 'label_ref'. - -'(pc)' - This refers to the address of the _current_ insn. It might have - been more consistent with other usage to make this the address of - the _next_ insn but this would be confusing because the length of - the current insn is to be computed. - - For normal insns, the length will be determined by value of the -'length' attribute. In the case of 'addr_vec' and '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: - -'ADJUST_INSN_LENGTH (INSN, LENGTH)' - If defined, modifies the length assigned to instruction INSN as a - function of the context in which it is used. 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 'addr_vec' - insn must be increased by two to compensate for the fact that - alignment may be required. - - The routine that returns 'get_attr_length' (the value of the '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: - - (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)))]) - - -File: gccint.info, Node: Constant Attributes, Next: Mnemonic Attribute, Prev: Insn Lengths, Up: Insn Attributes - -16.19.6 Constant Attributes ---------------------------- - -A special form of 'define_attr', where the expression for the default -value is a '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, - - (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")))) - - 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 'symbol_ref' form, but may -not use either the 'match_operand' form or 'eq_attr' forms involving -insn attributes. - - -File: gccint.info, Node: Mnemonic Attribute, Next: Delay Slots, Prev: Constant Attributes, Up: Insn Attributes - -16.19.7 Mnemonic Attribute --------------------------- - -The 'mnemonic' attribute is a string type attribute holding the -instruction mnemonic for an insn alternative. The attribute values will -automatically be generated by the machine description parser if there is -an attribute definition in the md file: - - (define_attr "mnemonic" "unknown" (const_string "unknown")) - - The default value can be freely chosen as long as it does not collide -with any of the instruction mnemonics. This value will be used whenever -the machine description parser is not able to determine the mnemonic -string. This might be the case for output templates containing more -than a single instruction as in '"mvcle\t%0,%1,0\;jo\t.-4"'. - - The 'mnemonic' attribute set is not generated automatically if the -instruction string is generated via C code. - - An existing 'mnemonic' attribute set in an insn definition will not be -overriden by the md file parser. That way it is possible to manually -set the instruction mnemonics for the cases where the md file parser -fails to determine it automatically. - - The 'mnemonic' attribute is useful for dealing with instruction -specific properties in the pipeline description without defining -additional insn attributes. - - (define_attr "ooo_expanded" "" - (cond [(eq_attr "mnemonic" "dlr,dsgr,d,dsgf,stam,dsgfr,dlgr") - (const_int 1)] - (const_int 0))) - - -File: gccint.info, Node: Delay Slots, Next: Processor pipeline description, Prev: Mnemonic Attribute, Up: Insn Attributes - -16.19.8 Delay Slot Scheduling ------------------------------ - -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 "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 -"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. - - The requirement of an insn needing one or more delay slots is indicated -via the 'define_delay' expression. It has the following form: - - (define_delay TEST - [DELAY-1 ANNUL-TRUE-1 ANNUL-FALSE-1 - DELAY-2 ANNUL-TRUE-2 ANNUL-FALSE-2 - ...]) - - TEST is an attribute test that indicates whether this '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 N must satisfy attribute test -DELAY-N. ANNUL-TRUE-N is an attribute test that specifies which insns -may be annulled if the branch is true. Similarly, 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, '(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 'md' file: - - (define_delay (eq_attr "type" "branch,call") - [(eq_attr "type" "!branch,call") (nil) (nil)]) - - Multiple '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 '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: - - (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)]) - - -File: gccint.info, Node: Processor pipeline description, Prev: Delay Slots, Up: Insn Attributes - -16.19.9 Specifying processor pipeline description -------------------------------------------------- - -To achieve better performance, most modern processors (super-pipelined, -superscalar RISC, and VLIW processors) have many "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 "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 "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 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 "pipeline description"). GCC machine -descriptions describe processor parallelism and functional unit -reservations for groups of instructions with the aid of "regular -expressions". - - The GCC instruction scheduler uses a "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 (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(1). - - 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. - - 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. - - (define_automaton AUTOMATA-NAMES) - - 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 'define_cpu_unit' and -'define_query_cpu_unit'. - - Each processor functional unit used in the description of instruction -reservations should be described by the following construction. - - (define_cpu_unit UNIT-NAMES [AUTOMATON-NAME]) - - UNIT-NAMES is a string giving the names of the functional units -separated by commas. Don't use name 'nothing', it is reserved for other -goals. - - AUTOMATON-NAME is a string giving the name of the automaton with which -the unit is bound. The automaton should be described in construction -'define_automaton'. You should give "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. - - The following construction describes CPU functional units analogously -to '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 VLIW insn templates). - - (define_query_cpu_unit UNIT-NAMES [AUTOMATON-NAME]) - - UNIT-NAMES is a string giving names of the functional units separated -by commas. - - AUTOMATON-NAME is a string giving the name of the automaton with which -the unit is bound. - - The following construction is the major one to describe pipeline -characteristics of an instruction. - - (define_insn_reservation INSN-NAME DEFAULT_LATENCY - CONDITION REGEXP) - - 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 'TARGET_SCHED_ADJUST_COST' -(*note Scheduling::). - - INSN-NAME is a string giving the internal name of the insn. The -internal names are used in constructions 'define_bypass' and in the -automaton description file generated for debugging. The internal name -has nothing in common with the names in 'define_insn'. It is a good -practice to use insn classes described in the processor manual. - - CONDITION defines what RTL insns are described by this construction. -You should remember that you will be in trouble if CONDITION for two or -more different '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 'symbol_ref'). It is also not checked during the pipeline -hazard recognizer work because it would slow down the recognizer -considerably. - - 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: - - 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 ")" - - * ',' is used for describing the start of the next cycle in the - reservation. - - * '|' is used for describing a reservation described by the first - regular expression *or* a reservation described by the second - regular expression *or* etc. - - * '+' is used for describing a reservation described by the first - regular expression *and* a reservation described by the second - regular expression *and* etc. - - * '*' is used for convenience and simply means a sequence in which - the regular expression are repeated NUMBER times with cycle - advancing (see ','). - - * 'cpu_function_unit_name' denotes reservation of the named - functional unit. - - * 'reservation_name' -- see description of construction - 'define_reservation'. - - * 'nothing' denotes no unit reservations. - - 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 - - (define_reservation RESERVATION-NAME REGEXP) - - RESERVATION-NAME is a string giving name of 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 'nothing'. - - The following construction is used to describe exceptions in the -latency time for given instruction pair. This is so called bypasses. - - (define_bypass NUMBER OUT_INSN_NAMES IN_INSN_NAMES - [GUARD]) - - NUMBER defines when the result generated by the instructions given in -string OUT_INSN_NAMES will be ready for the instructions given in string -IN_INSN_NAMES. Each of these strings is a comma-separated list of -filename-style globs and they refer to the names of -'define_insn_reservation's. For example: - (define_bypass 1 "cpu1_load_*, cpu1_store_*" "cpu1_load_*") - defines a bypass between instructions that start with 'cpu1_load_' or -'cpu1_store_' and those that start with 'cpu1_load_'. - - 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 'store' (not a stored value). - - If there are more one bypass with the same output and input insns, the -chosen bypass is the first bypass with a guard in description whose -guard function returns nonzero. If there is no such bypass, then bypass -without the guard function is chosen. - - The following five constructions are usually used to describe VLIW -processors, or more precisely, to describe a placement of small -instructions into VLIW instruction slots. They can be used for RISC -processors, too. - - (exclusion_set UNIT-NAMES UNIT-NAMES) - (presence_set UNIT-NAMES PATTERNS) - (final_presence_set UNIT-NAMES PATTERNS) - (absence_set UNIT-NAMES PATTERNS) - (final_absence_set UNIT-NAMES PATTERNS) - - UNIT-NAMES is a string giving names of functional units separated by -commas. - - 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 ('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 ('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 VLIW 'slot1' is reserved after 'slot0' reservation. We could -describe it by the following construction - - (presence_set "slot1" "slot0") - - Or 'slot1' is reserved only after 'slot0' and unit 'b0' reservation. -In this case we could write - - (presence_set "slot1" "slot0 b0") - - The third construction ('final_presence_set') is analogous to -'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 'presence_set' is done on the source state reservation, -checking for '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 - - (presence_set "slot1" "slot0") - - the following insn will be never issued (because 'slot1' requires -'slot0' which is absent in the source state). - - (define_reservation "insn_and_nop" "slot0 + slot1") - - but it can be issued if we use analogous 'final_presence_set'. - - The forth construction ('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 'exclusion_set' is analogous to this one but it is -symmetric). For example it might be useful in a VLIW description to say -that 'slot0' cannot be reserved after either 'slot1' or 'slot2' have -been reserved. This can be described as: - - (absence_set "slot0" "slot1, slot2") - - Or 'slot2' can not be reserved if 'slot0' and unit 'b0' are reserved or -'slot1' and unit 'b1' are reserved. In this case we could write - - (absence_set "slot2" "slot0 b0, slot1 b1") - - All functional units mentioned in a set should belong to the same -automaton. - - The last construction ('final_absence_set') is analogous to -'absence_set' but checking is done on the result (state) reservation. -See comments for 'final_presence_set'. - - You can control the generator of the pipeline hazard recognizer with -the following construction. - - (automata_option OPTIONS) - - OPTIONS is a string giving options which affect the generated code. -Currently there are the following options: - - * "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. - - * "time" means printing time statistics about the generation of - automata. - - * "stats" means printing statistics about the generated automata such - as the number of DFA states, NDFA states and arcs. - - * "v" means a generation of the file describing the result automata. - The file has suffix '.dfa' and can be used for the description - verification and debugging. - - * "w" means a generation of warning instead of error for non-critical - errors. - - * "no-comb-vect" prevents the automaton generator from generating two - data structures and comparing them for space efficiency. Using a - comb vector to represent transitions may be better, but it can be - very expensive to construct. This option is useful if the build - process spends an unacceptably long time in genautomata. - - * "ndfa" makes nondeterministic finite state automata. This affects - the treatment of operator '|' 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. - - * "collapse-ndfa" modifies the behaviour of the generator when - producing an automaton. An additional state transition to collapse - a nondeterministic NDFA state to a deterministic DFA state is - generated. It can be triggered by passing 'const0_rtx' to - state_transition. In such an automaton, cycle advance transitions - are available only for these collapsed states. This option is - useful for ports that want to use the 'ndfa' option, but also want - to use 'define_query_cpu_unit' to assign units to insns issued in a - cycle. - - * "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 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. - - As an example, consider a superscalar 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. - - (define_cpu_unit "i0_pipeline, i1_pipeline, f_pipeline") - (define_cpu_unit "port0, port1") - - 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 - - (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") - - To simplify the description we could describe the following reservation - - (define_reservation "finish" "port0|port1") - - and use it in all 'define_insn_reservation' as in the following -construction - - (define_insn_reservation "simple" 2 (eq_attr "type" "int") - "(i0_pipeline | i1_pipeline), finish") - - ---------- Footnotes ---------- - - (1) 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. - - -File: gccint.info, Node: Conditional Execution, Next: Define Subst, Prev: Insn Attributes, Up: Machine Desc - -16.20 Conditional Execution -=========================== - -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 '.md' file. An -alternative is the 'define_cond_exec' template. - - (define_cond_exec - [PREDICATE-PATTERN] - "CONDITION" - "OUTPUT-TEMPLATE" - "OPTIONAL-INSN-ATTRIBUES") - - 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 -'match_operator' to match several relational operators at once. Any -'match_operand' operands must have no more than one alternative. - - CONDITION is a C expression that must be true for the generated pattern -to match. - - OUTPUT-TEMPLATE is a string similar to the 'define_insn' output -template (*note Output Template::), except that the '*' and '@' 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 'current_insn_predicate' that -will contain the entire predicate if the current insn is predicated, and -will otherwise be 'NULL'. - - OPTIONAL-INSN-ATTRIBUTES is an optional vector of attributes that gets -appended to the insn attributes of the produced cond_exec rtx. It can -be used to add some distinguishing attribute to cond_exec rtxs produced -that way. An example usage would be to use this attribute in -conjunction with attributes on the main pattern to disable particular -alternatives under certain conditions. - - When 'define_cond_exec' is used, an implicit reference to the -'predicable' instruction attribute is made. *Note Insn Attributes::. -This attribute must be a boolean (i.e. have exactly two elements in its -LIST-OF-VALUES), with the possible values being 'no' and 'yes'. The -default and all uses in the insns must be a simple constant, not a -complex expressions. It may, however, depend on the alternative, by -using a comma-separated list of values. If that is the case, the port -should also define an 'enabled' attribute (*note Disable Insn -Alternatives::), which should also allow only 'no' and 'yes' as its -values. - - For each 'define_insn' for which the 'predicable' attribute is true, a -new 'define_insn' pattern will be generated that matches a predicated -version of the instruction. For example, - - (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")))] - "TEST1" - "add %2,%1,%0") - - (define_cond_exec - [(ne (match_operand:CC 0 "register_operand" "c") - (const_int 0))] - "TEST2" - "(%0)") - -generates a new pattern - - (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"))))] - "(TEST2) && (TEST1)" - "(%3) add %2,%1,%0") - - -File: gccint.info, Node: Define Subst, Next: Constant Definitions, Prev: Conditional Execution, Up: Machine Desc - -16.21 RTL Templates Transformations -=================================== - -For some hardware architectures there are common cases when the RTL -templates for the instructions can be derived from the other RTL -templates using simple transformations. E.g., 'i386.md' contains an RTL -template for the ordinary 'sub' instruction-- '*subsi_1', and for the -'sub' instruction with subsequent zero-extension--'*subsi_1_zext'. Such -cases can be easily implemented by a single meta-template capable of -generating a modified case based on the initial one: - - (define_subst "NAME" - [INPUT-TEMPLATE] - "CONDITION" - [OUTPUT-TEMPLATE]) - INPUT-TEMPLATE is a pattern describing the source RTL template, which -will be transformed. - - CONDITION is a C expression that is conjunct with the condition from -the input-template to generate a condition to be used in the -output-template. - - OUTPUT-TEMPLATE is a pattern that will be used in the resulting -template. - - 'define_subst' mechanism is tightly coupled with the notion of the -subst attribute (*note Subst Iterators::). The use of 'define_subst' is -triggered by a reference to a subst attribute in the transforming RTL -template. This reference initiates duplication of the source RTL -template and substitution of the attributes with their values. The -source RTL template is left unchanged, while the copy is transformed by -'define_subst'. This transformation can fail in the case when the -source RTL template is not matched against the input-template of the -'define_subst'. In such case the copy is deleted. - - 'define_subst' can be used only in 'define_insn' and 'define_expand', -it cannot be used in other expressions (e.g. in -'define_insn_and_split'). - -* Menu: - -* Define Subst Example:: Example of 'define_subst' work. -* Define Subst Pattern Matching:: Process of template comparison. -* Define Subst Output Template:: Generation of output template. - - -File: gccint.info, Node: Define Subst Example, Next: Define Subst Pattern Matching, Up: Define Subst - -16.21.1 'define_subst' Example ------------------------------- - -To illustrate how 'define_subst' works, let us examine a simple template -transformation. - - Suppose there are two kinds of instructions: one that touches flags and -the other that does not. The instructions of the second type could be -generated with the following 'define_subst': - - (define_subst "add_clobber_subst" - [(set (match_operand:SI 0 "" "") - (match_operand:SI 1 "" ""))] - "" - [(set (match_dup 0) - (match_dup 1)) - (clobber (reg:CC FLAGS_REG))] - - This 'define_subst' can be applied to any RTL pattern containing 'set' -of mode SI and generates a copy with clobber when it is applied. - - Assume there is an RTL template for a 'max' instruction to be used in -'define_subst' mentioned above: - - (define_insn "maxsi" - [(set (match_operand:SI 0 "register_operand" "=r") - (max:SI - (match_operand:SI 1 "register_operand" "r") - (match_operand:SI 2 "register_operand" "r")))] - "" - "max\t{%2, %1, %0|%0, %1, %2}" - [...]) - - To mark the RTL template for 'define_subst' application, -subst-attributes are used. They should be declared in advance: - - (define_subst_attr "add_clobber_name" "add_clobber_subst" "_noclobber" "_clobber") - - Here 'add_clobber_name' is the attribute name, 'add_clobber_subst' is -the name of the corresponding 'define_subst', the third argument -('_noclobber') is the attribute value that would be substituted into the -unchanged version of the source RTL template, and the last argument -('_clobber') is the value that would be substituted into the second, -transformed, version of the RTL template. - - Once the subst-attribute has been defined, it should be used in RTL -templates which need to be processed by the 'define_subst'. So, the -original RTL template should be changed: - - (define_insn "maxsi<add_clobber_name>" - [(set (match_operand:SI 0 "register_operand" "=r") - (max:SI - (match_operand:SI 1 "register_operand" "r") - (match_operand:SI 2 "register_operand" "r")))] - "" - "max\t{%2, %1, %0|%0, %1, %2}" - [...]) - - The result of the 'define_subst' usage would look like the following: - - (define_insn "maxsi_noclobber" - [(set (match_operand:SI 0 "register_operand" "=r") - (max:SI - (match_operand:SI 1 "register_operand" "r") - (match_operand:SI 2 "register_operand" "r")))] - "" - "max\t{%2, %1, %0|%0, %1, %2}" - [...]) - (define_insn "maxsi_clobber" - [(set (match_operand:SI 0 "register_operand" "=r") - (max:SI - (match_operand:SI 1 "register_operand" "r") - (match_operand:SI 2 "register_operand" "r"))) - (clobber (reg:CC FLAGS_REG))] - "" - "max\t{%2, %1, %0|%0, %1, %2}" - [...]) - - -File: gccint.info, Node: Define Subst Pattern Matching, Next: Define Subst Output Template, Prev: Define Subst Example, Up: Define Subst - -16.21.2 Pattern Matching in 'define_subst' ------------------------------------------- - -All expressions, allowed in 'define_insn' or 'define_expand', are -allowed in the input-template of 'define_subst', except 'match_par_dup', -'match_scratch', 'match_parallel'. The meanings of expressions in the -input-template were changed: - - 'match_operand' matches any expression (possibly, a subtree in -RTL-template), if modes of the 'match_operand' and this expression are -the same, or mode of the 'match_operand' is 'VOIDmode', or this -expression is 'match_dup', 'match_op_dup'. If the expression is -'match_operand' too, and predicate of 'match_operand' from the input -pattern is not empty, then the predicates are compared. That can be -used for more accurate filtering of accepted RTL-templates. - - 'match_operator' matches common operators (like 'plus', 'minus'), -'unspec', 'unspec_volatile' operators and 'match_operator's from the -original pattern if the modes match and 'match_operator' from the input -pattern has the same number of operands as the operator from the -original pattern. - - -File: gccint.info, Node: Define Subst Output Template, Prev: Define Subst Pattern Matching, Up: Define Subst - -16.21.3 Generation of output template in 'define_subst' -------------------------------------------------------- - -If all necessary checks for 'define_subst' application pass, a new -RTL-pattern, based on the output-template, is created to replace the old -template. Like in input-patterns, meanings of some RTL expressions are -changed when they are used in output-patterns of a 'define_subst'. -Thus, 'match_dup' is used for copying the whole expression from the -original pattern, which matched corresponding 'match_operand' from the -input pattern. - - 'match_dup N' is used in the output template to be replaced with the -expression from the original pattern, which matched 'match_operand N' -from the input pattern. As a consequence, 'match_dup' cannot be used to -point to 'match_operand's from the output pattern, it should always -refer to a 'match_operand' from the input pattern. - - In the output template one can refer to the expressions from the -original pattern and create new ones. For instance, some operands could -be added by means of standard 'match_operand'. - - After replacing 'match_dup' with some RTL-subtree from the original -pattern, it could happen that several 'match_operand's in the output -pattern have the same indexes. It is unknown, how many and what indexes -would be used in the expression which would replace 'match_dup', so such -conflicts in indexes are inevitable. To overcome this issue, -'match_operands' and 'match_operators', which were introduced into the -output pattern, are renumerated when all 'match_dup's are replaced. - - Number of alternatives in 'match_operand's introduced into the output -template 'M' could differ from the number of alternatives in the -original pattern 'N', so in the resultant pattern there would be 'N*M' -alternatives. Thus, constraints from the original pattern would be -duplicated 'N' times, constraints from the output pattern would be -duplicated 'M' times, producing all possible combinations. - - -File: gccint.info, Node: Constant Definitions, Next: Iterators, Prev: Define Subst, Up: Machine Desc - -16.22 Constant Definitions -========================== - -Using literal constants inside instruction patterns reduces legibility -and can be a maintenance problem. - - To overcome this problem, you may use the '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 -'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 - - (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") - - You could write: - - (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") - - The constants that are defined with a define_constant are also output -in the insn-codes.h header file as #defines. - - You can also use the machine description file to define enumerations. -Like the constants defined by 'define_constant', these enumerations are -visible to both the machine description file and the main C code. - - The syntax is as follows: - - (define_c_enum "NAME" [ - VALUE0 - VALUE1 - ... - VALUEN - ]) - - This definition causes the equivalent of the following C code to appear -in 'insn-constants.h': - - enum NAME { - VALUE0 = 0, - VALUE1 = 1, - ... - VALUEN = N - }; - #define NUM_CNAME_VALUES (N + 1) - - where CNAME is the capitalized form of NAME. It also makes each VALUEI -available in the machine description file, just as if it had been -declared with: - - (define_constants [(VALUEI I)]) - - Each VALUEI is usually an upper-case identifier and usually begins with -CNAME. - - You can split the enumeration definition into as many statements as you -like. The above example is directly equivalent to: - - (define_c_enum "NAME" [VALUE0]) - (define_c_enum "NAME" [VALUE1]) - ... - (define_c_enum "NAME" [VALUEN]) - - Splitting the enumeration helps to improve the modularity of each -individual '.md' file. For example, if a port defines its -synchronization instructions in a separate 'sync.md' file, it is -convenient to define all synchronization-specific enumeration values in -'sync.md' rather than in the main '.md' file. - - Some enumeration names have special significance to GCC: - -'unspecv' - If an enumeration called 'unspecv' is defined, GCC will use it when - printing out 'unspec_volatile' expressions. For example: - - (define_c_enum "unspecv" [ - UNSPECV_BLOCKAGE - ]) - - causes GCC to print '(unspec_volatile ... 0)' as: - - (unspec_volatile ... UNSPECV_BLOCKAGE) - -'unspec' - If an enumeration called 'unspec' is defined, GCC will use it when - printing out 'unspec' expressions. GCC will also use it when - printing out 'unspec_volatile' expressions unless an 'unspecv' - enumeration is also defined. You can therefore decide whether to - keep separate enumerations for volatile and non-volatile - expressions or whether to use the same enumeration for both. - - Another way of defining an enumeration is to use 'define_enum': - - (define_enum "NAME" [ - VALUE0 - VALUE1 - ... - VALUEN - ]) - - This directive implies: - - (define_c_enum "NAME" [ - CNAME_CVALUE0 - CNAME_CVALUE1 - ... - CNAME_CVALUEN - ]) - - where CVALUEI is the capitalized form of VALUEI. However, unlike -'define_c_enum', the enumerations defined by 'define_enum' can be used -in attribute specifications (*note define_enum_attr::). - - -File: gccint.info, Node: Iterators, Prev: Constant Definitions, Up: Machine Desc - -16.23 Iterators -=============== - -Ports often need to define similar patterns for more than one machine -mode or for more than one rtx code. GCC provides some simple iterator -facilities to make this process easier. - -* Menu: - -* Mode Iterators:: Generating variations of patterns for different modes. -* Code Iterators:: Doing the same for codes. -* Int Iterators:: Doing the same for integers. -* Subst Iterators:: Generating variations of patterns for define_subst. - - -File: gccint.info, Node: Mode Iterators, Next: Code Iterators, Up: Iterators - -16.23.1 Mode Iterators ----------------------- - -Ports often need to define similar patterns for two or more different -modes. For example: - - * If a processor has hardware support for both single and double - floating-point arithmetic, the 'SFmode' patterns tend to be very - similar to the 'DFmode' ones. - - * If a port uses 'SImode' pointers in one configuration and 'DImode' - pointers in another, it will usually have very similar 'SImode' and - 'DImode' patterns for manipulating pointers. - - Mode iterators allow several patterns to be instantiated from one '.md' -file template. They can be used with any type of rtx-based construct, -such as a 'define_insn', 'define_split', or 'define_peephole2'. - -* Menu: - -* Defining Mode Iterators:: Defining a new mode iterator. -* Substitutions:: Combining mode iterators with substitutions -* Examples:: Examples - - -File: gccint.info, Node: Defining Mode Iterators, Next: Substitutions, Up: Mode Iterators - -16.23.1.1 Defining Mode Iterators -................................. - -The syntax for defining a mode iterator is: - - (define_mode_iterator NAME [(MODE1 "COND1") ... (MODEN "CONDN")]) - - This allows subsequent '.md' file constructs to use the mode suffix -':NAME'. Every construct that does so will be expanded N times, once -with every use of ':NAME' replaced by ':MODE1', once with every use -replaced by ':MODE2', and so on. In the expansion for a particular -MODEI, every C condition will also require that CONDI be true. - - For example: - - (define_mode_iterator P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) - - defines a new mode suffix ':P'. Every construct that uses ':P' will be -expanded twice, once with every ':P' replaced by ':SI' and once with -every ':P' replaced by ':DI'. The ':SI' version will only apply if -'Pmode == SImode' and the ':DI' version will only apply if 'Pmode == -DImode'. - - As with other '.md' conditions, an empty string is treated as "always -true". '(MODE "")' can also be abbreviated to 'MODE'. For example: - - (define_mode_iterator GPR [SI (DI "TARGET_64BIT")]) - - means that the ':DI' expansion only applies if 'TARGET_64BIT' but that -the ':SI' expansion has no such constraint. - - Iterators are applied in the order they are defined. This can be -significant if two iterators are used in a construct that requires -substitutions. *Note Substitutions::. - - -File: gccint.info, Node: Substitutions, Next: Examples, Prev: Defining Mode Iterators, Up: Mode Iterators - -16.23.1.2 Substitution in Mode Iterators -........................................ - -If an '.md' file construct uses mode iterators, each version of the -construct will often need slightly different strings or modes. For -example: - - * When a 'define_expand' defines several 'addM3' patterns (*note - Standard Names::), each expander will need to use the appropriate - mode name for M. - - * When a 'define_insn' defines several instruction patterns, each - instruction will often use a different assembler mnemonic. - - * When a 'define_insn' requires operands with different modes, using - an iterator for one of the operand modes usually requires a - specific mode for the other operand(s). - - GCC supports such variations through a system of "mode attributes". -There are two standard attributes: 'mode', which is the name of the mode -in lower case, and 'MODE', which is the same thing in upper case. You -can define other attributes using: - - (define_mode_attr NAME [(MODE1 "VALUE1") ... (MODEN "VALUEN")]) - - where NAME is the name of the attribute and VALUEI is the value -associated with MODEI. - - When GCC replaces some :ITERATOR with :MODE, it will scan each string -and mode in the pattern for sequences of the form '<ITERATOR:ATTR>', -where ATTR is the name of a mode attribute. If the attribute is defined -for MODE, the whole '<...>' sequence will be replaced by the appropriate -attribute value. - - For example, suppose an '.md' file has: - - (define_mode_iterator P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) - (define_mode_attr load [(SI "lw") (DI "ld")]) - - If one of the patterns that uses ':P' contains the string -'"<P:load>\t%0,%1"', the 'SI' version of that pattern will use -'"lw\t%0,%1"' and the 'DI' version will use '"ld\t%0,%1"'. - - Here is an example of using an attribute for a mode: - - (define_mode_iterator LONG [SI DI]) - (define_mode_attr SHORT [(SI "HI") (DI "SI")]) - (define_insn ... - (sign_extend:LONG (match_operand:<LONG:SHORT> ...)) ...) - - The 'ITERATOR:' prefix may be omitted, in which case the substitution -will be attempted for every iterator expansion. - - -File: gccint.info, Node: Examples, Prev: Substitutions, Up: Mode Iterators - -16.23.1.3 Mode Iterator Examples -................................ - -Here is an example from the MIPS port. It defines the following modes -and attributes (among others): - - (define_mode_iterator GPR [SI (DI "TARGET_64BIT")]) - (define_mode_attr d [(SI "") (DI "d")]) - - and uses the following template to define both 'subsi3' and 'subdi3': - - (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>")]) - - This is exactly equivalent to: - - (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")]) - - -File: gccint.info, Node: Code Iterators, Next: Int Iterators, Prev: Mode Iterators, Up: Iterators - -16.23.2 Code Iterators ----------------------- - -Code iterators operate in a similar way to mode iterators. *Note Mode -Iterators::. - - The construct: - - (define_code_iterator NAME [(CODE1 "COND1") ... (CODEN "CONDN")]) - - defines a pseudo rtx code NAME that can be instantiated as CODEI if -condition CONDI is true. Each CODEI must have the same rtx format. -*Note RTL Classes::. - - As with mode iterators, each pattern that uses NAME will be expanded N -times, once with all uses of NAME replaced by CODE1, once with all uses -replaced by CODE2, and so on. *Note Defining Mode Iterators::. - - It is possible to define attributes for codes as well as for modes. -There are two standard code attributes: 'code', the name of the code in -lower case, and 'CODE', the name of the code in upper case. Other -attributes are defined using: - - (define_code_attr NAME [(CODE1 "VALUE1") ... (CODEN "VALUEN")]) - - Here's an example of code iterators in action, taken from the MIPS -port: - - (define_code_iterator 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; - }) - - This is equivalent to: - - (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; - }) - - ... - - -File: gccint.info, Node: Int Iterators, Next: Subst Iterators, Prev: Code Iterators, Up: Iterators - -16.23.3 Int Iterators ---------------------- - -Int iterators operate in a similar way to code iterators. *Note Code -Iterators::. - - The construct: - - (define_int_iterator NAME [(INT1 "COND1") ... (INTN "CONDN")]) - - defines a pseudo integer constant NAME that can be instantiated as INTI -if condition CONDI is true. Each INT must have the same rtx format. -*Note RTL Classes::. Int iterators can appear in only those rtx fields -that have 'i' as the specifier. This means that each INT has to be a -constant defined using define_constant or define_c_enum. - - As with mode and code iterators, each pattern that uses NAME will be -expanded N times, once with all uses of NAME replaced by INT1, once with -all uses replaced by INT2, and so on. *Note Defining Mode Iterators::. - - It is possible to define attributes for ints as well as for codes and -modes. Attributes are defined using: - - (define_int_attr NAME [(INT1 "VALUE1") ... (INTN "VALUEN")]) - - Here's an example of int iterators in action, taken from the ARM port: - - (define_int_iterator QABSNEG [UNSPEC_VQABS UNSPEC_VQNEG]) - - (define_int_attr absneg [(UNSPEC_VQABS "abs") (UNSPEC_VQNEG "neg")]) - - (define_insn "neon_vq<absneg><mode>" - [(set (match_operand:VDQIW 0 "s_register_operand" "=w") - (unspec:VDQIW [(match_operand:VDQIW 1 "s_register_operand" "w") - (match_operand:SI 2 "immediate_operand" "i")] - QABSNEG))] - "TARGET_NEON" - "vq<absneg>.<V_s_elem>\t%<V_reg>0, %<V_reg>1" - [(set_attr "type" "neon_vqneg_vqabs")] - ) - - This is equivalent to: - - (define_insn "neon_vqabs<mode>" - [(set (match_operand:VDQIW 0 "s_register_operand" "=w") - (unspec:VDQIW [(match_operand:VDQIW 1 "s_register_operand" "w") - (match_operand:SI 2 "immediate_operand" "i")] - UNSPEC_VQABS))] - "TARGET_NEON" - "vqabs.<V_s_elem>\t%<V_reg>0, %<V_reg>1" - [(set_attr "type" "neon_vqneg_vqabs")] - ) - - (define_insn "neon_vqneg<mode>" - [(set (match_operand:VDQIW 0 "s_register_operand" "=w") - (unspec:VDQIW [(match_operand:VDQIW 1 "s_register_operand" "w") - (match_operand:SI 2 "immediate_operand" "i")] - UNSPEC_VQNEG))] - "TARGET_NEON" - "vqneg.<V_s_elem>\t%<V_reg>0, %<V_reg>1" - [(set_attr "type" "neon_vqneg_vqabs")] - ) - - -File: gccint.info, Node: Subst Iterators, Prev: Int Iterators, Up: Iterators - -16.23.4 Subst Iterators ------------------------ - -Subst iterators are special type of iterators with the following -restrictions: they could not be declared explicitly, they always have -only two values, and they do not have explicit dedicated name. -Subst-iterators are triggered only when corresponding subst-attribute is -used in RTL-pattern. - - Subst iterators transform templates in the following way: the templates -are duplicated, the subst-attributes in these templates are replaced -with the corresponding values, and a new attribute is implicitly added -to the given 'define_insn'/'define_expand'. The name of the added -attribute matches the name of 'define_subst'. Such attributes are -declared implicitly, and it is not allowed to have a 'define_attr' named -as a 'define_subst'. - - Each subst iterator is linked to a 'define_subst'. It is declared -implicitly by the first appearance of the corresponding -'define_subst_attr', and it is not allowed to define it explicitly. - - Declarations of subst-attributes have the following syntax: - - (define_subst_attr "NAME" - "SUBST-NAME" - "NO-SUBST-VALUE" - "SUBST-APPLIED-VALUE") - - NAME is a string with which the given subst-attribute could be referred -to. - - SUBST-NAME shows which 'define_subst' should be applied to an -RTL-template if the given subst-attribute is present in the -RTL-template. - - NO-SUBST-VALUE is a value with which subst-attribute would be replaced -in the first copy of the original RTL-template. - - SUBST-APPLIED-VALUE is a value with which subst-attribute would be -replaced in the second copy of the original RTL-template. - - -File: gccint.info, Node: Target Macros, Next: Host Config, Prev: Machine Desc, Up: Top - -17 Target Description Macros and Functions -****************************************** - -In addition to the file 'MACHINE.md', a machine description includes a C -header file conventionally given the name 'MACHINE.h' and a C source -file named '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 '.md' file. The file 'tm.h' should be a link to -'MACHINE.h'. The header file 'config.h' includes 'tm.h' and most -compiler source files include 'config.h'. The source file defines a -variable 'targetm', which is a structure containing pointers to -functions and data relating to the target machine. '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 '.h' -file. - -* Menu: - -* Target Structure:: The 'targetm' variable. -* Driver:: Controlling how the driver runs the compilation passes. -* Run-time Target:: Defining '-m' options like '-m68000' and '-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 '-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 '__attribute__'. -* Emulated TLS:: Emulated TLS support. -* MIPS Coprocessors:: MIPS coprocessor support and how to customize it. -* PCH Target:: Validity checking for precompiled headers. -* C++ ABI:: Controlling C++ ABI changes. -* Named Address Spaces:: Adding support for named address spaces -* Misc:: Everything else. - - -File: gccint.info, Node: Target Structure, Next: Driver, Up: Target Macros - -17.1 The Global 'targetm' Variable -================================== - - -- Variable: struct gcc_target targetm - The target '.c' file must define the global 'targetm' variable - which contains pointers to functions and data relating to the - target machine. The variable is declared in 'target.h'; - 'target-def.h' defines the macro 'TARGET_INITIALIZER' which is used - to initialize the variable, and macros for the default initializers - for elements of the structure. The '.c' file should override those - macros for which the default definition is inappropriate. For - example: - #include "target.h" - #include "target-def.h" - - /* Initialize the GCC target structure. */ - - #undef TARGET_COMP_TYPE_ATTRIBUTES - #define TARGET_COMP_TYPE_ATTRIBUTES MACHINE_comp_type_attributes - - struct gcc_target targetm = TARGET_INITIALIZER; - - Where a macro should be defined in the '.c' file in this manner to form -part of the 'targetm' structure, it is documented below as a "Target -Hook" with a prototype. Many macros will change in future from being -defined in the '.h' file to being part of the 'targetm' structure. - - Similarly, there is a 'targetcm' variable for hooks that are specific -to front ends for C-family languages, documented as "C Target Hook". -This is declared in 'c-family/c-target.h', the initializer -'TARGETCM_INITIALIZER' in 'c-family/c-target-def.h'. If targets -initialize 'targetcm' themselves, they should set -'target_has_targetcm=yes' in 'config.gcc'; otherwise a default -definition is used. - - Similarly, there is a 'targetm_common' variable for hooks that are -shared between the compiler driver and the compilers proper, documented -as "Common Target Hook". This is declared in 'common/common-target.h', -the initializer 'TARGETM_COMMON_INITIALIZER' in -'common/common-target-def.h'. If targets initialize 'targetm_common' -themselves, they should set 'target_has_targetm_common=yes' in -'config.gcc'; otherwise a default definition is used. - - -File: gccint.info, Node: Driver, Next: Run-time Target, Prev: Target Structure, Up: Target Macros - -17.2 Controlling the Compilation Driver, 'gcc' -============================================== - -You can control the compilation driver. - - -- Macro: 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 '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 '%<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. - - -- Macro: OPTION_DEFAULT_SPECS - A list of specs used to support configure-time default options - (i.e. '--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 'config.gcc' for the target. The second item is - a spec to apply if a default with this name was specified. The - string '%(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 'specs' files and processing 'DRIVER_SELF_SPECS', - using the same mechanism as 'DRIVER_SELF_SPECS'. - - Do not define this macro if it does not need to do anything. - - -- Macro: 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. - - -- Macro: CPLUSPLUS_CPP_SPEC - This macro is just like 'CPP_SPEC', but is used for C++, rather - than C. If you do not define this macro, then the value of - 'CPP_SPEC' (if any) will be used instead. - - -- Macro: CC1_SPEC - A C string constant that tells the GCC driver program options to - pass to 'cc1', 'cc1plus', '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. - - -- Macro: CC1PLUS_SPEC - A C string constant that tells the GCC driver program options to - pass to 'cc1plus'. It can also specify how to translate options - you give to GCC into options for GCC to pass to the '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 'cc1plus' - so there is no need to duplicate the contents of CC1_SPEC in - CC1PLUS_SPEC. - - -- Macro: 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 'sun3.h' for an example of this. - - Do not define this macro if it does not need to do anything. - - -- Macro: 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 'mips.h' for an example of this. - - Do not define this macro if it does not need to do anything. - - -- Macro: 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, '-', 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 '-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 '%{pipe:%e}' - construct; see 'mips.h' for instance. - - -- Macro: 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. - - -- Macro: LIB_SPEC - Another C string constant used much like 'LINK_SPEC'. The - difference between the two is that '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 'gcc.c'. - - -- Macro: LIBGCC_SPEC - Another C string constant that tells the GCC driver program how and - when to place a reference to 'libgcc.a' into the linker command - line. This constant is placed both before and after the value of - 'LIB_SPEC'. - - If this macro is not defined, the GCC driver provides a default - that passes the string '-lgcc' to the linker. - - -- Macro: REAL_LIBGCC_SPEC - By default, if 'ENABLE_SHARED_LIBGCC' is defined, the 'LIBGCC_SPEC' - is not directly used by the driver program but is instead modified - to refer to different versions of 'libgcc.a' depending on the - values of the command line flags '-static', '-shared', - '-static-libgcc', and '-shared-libgcc'. On targets where these - modifications are inappropriate, define 'REAL_LIBGCC_SPEC' instead. - 'REAL_LIBGCC_SPEC' tells the driver how to place a reference to - 'libgcc' on the link command line, but, unlike 'LIBGCC_SPEC', it is - used unmodified. - - -- Macro: USE_LD_AS_NEEDED - A macro that controls the modifications to 'LIBGCC_SPEC' mentioned - in 'REAL_LIBGCC_SPEC'. If nonzero, a spec will be generated that - uses '--as-needed' or equivalent options and the shared 'libgcc' in - place of the static exception handler library, when linking without - any of '-static', '-static-libgcc', or '-shared-libgcc'. - - -- Macro: LINK_EH_SPEC - If defined, this C string constant is added to 'LINK_SPEC'. When - 'USE_LD_AS_NEEDED' is zero or undefined, it also affects the - modifications to 'LIBGCC_SPEC' mentioned in 'REAL_LIBGCC_SPEC'. - - -- Macro: STARTFILE_SPEC - Another C string constant used much like 'LINK_SPEC'. The - difference between the two is that '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 'gcc.c'. - - -- Macro: ENDFILE_SPEC - Another C string constant used much like 'LINK_SPEC'. The - difference between the two is that '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. - - -- Macro: THREAD_MODEL_SPEC - GCC '-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 - 'THREAD_MODEL_SPEC' such that it evaluates to a string without - blanks that names one of the recognized thread models. '%*', the - default value of this macro, will expand to the value of - 'thread_file' set in 'config.gcc'. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: EXTRA_SPECS - Define this macro to provide additional specifications to put in - the 'specs' file that can be used in various specifications like - '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. - - 'EXTRA_SPECS' is useful when an architecture contains several - related targets, which have various '..._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 'EXTRA_SPECS' to - define either '_CALL_SYSV' when the System V calling sequence is - used or '_CALL_AIX' when the older AIX-based calling sequence is - used. - - The 'config/rs6000/rs6000.h' target file defines: - - #define EXTRA_SPECS \ - { "cpp_sysv_default", CPP_SYSV_DEFAULT }, - - #define CPP_SYS_DEFAULT "" - - The 'config/rs6000/sysv.h' target file defines: - #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" - - while the 'config/rs6000/eabiaix.h' target file defines - 'CPP_SYSV_DEFAULT' as: - - #undef CPP_SYSV_DEFAULT - #define CPP_SYSV_DEFAULT "-D_CALL_AIX" - - -- Macro: LINK_LIBGCC_SPECIAL_1 - Define this macro if the driver program should find the library - 'libgcc.a'. If you do not define this macro, the driver program - will pass the argument '-lgcc' to tell the linker to do the search. - - -- Macro: LINK_GCC_C_SEQUENCE_SPEC - The sequence in which libgcc and libc are specified to the linker. - By default this is '%G %L %G'. - - -- Macro: 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 - '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 - 'LINK_GCC_C_SEQUENCE_SPEC' instead. - - -- Common Target Hook: bool TARGET_ALWAYS_STRIP_DOTDOT - True if '..' components should always be removed from directory - names computed relative to GCC's internal directories, false - (default) if such components should be preserved and directory - names containing them passed to other tools such as the linker. - - -- Macro: 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 - 'MULTILIB_OPTIONS'. - - Do not define this macro if 'MULTILIB_OPTIONS' is not defined in - the target makefile fragment or if none of the options listed in - 'MULTILIB_OPTIONS' are set by default. *Note Target Fragment::. - - -- Macro: RELATIVE_PREFIX_NOT_LINKDIR - Define this macro to tell 'gcc' that it should only translate a - '-B' prefix into a '-L' linker option if the prefix indicates an - absolute file name. - - -- Macro: MD_EXEC_PREFIX - If defined, this macro is an additional prefix to try after - 'STANDARD_EXEC_PREFIX'. 'MD_EXEC_PREFIX' is not searched when the - compiler is built as a cross compiler. If you define - 'MD_EXEC_PREFIX', then be sure to add it to the list of directories - used to find the assembler in 'configure.in'. - - -- Macro: STANDARD_STARTFILE_PREFIX - Define this macro as a C string constant if you wish to override - the standard choice of 'libdir' as the default prefix to try when - searching for startup files such as 'crt0.o'. - 'STANDARD_STARTFILE_PREFIX' is not searched when the compiler is - built as a cross compiler. - - -- Macro: STANDARD_STARTFILE_PREFIX_1 - Define this macro as a C string constant if you wish to override - the standard choice of '/lib' as a prefix to try after the default - prefix when searching for startup files such as 'crt0.o'. - 'STANDARD_STARTFILE_PREFIX_1' is not searched when the compiler is - built as a cross compiler. - - -- Macro: STANDARD_STARTFILE_PREFIX_2 - Define this macro as a C string constant if you wish to override - the standard choice of '/lib' as yet another prefix to try after - the default prefix when searching for startup files such as - 'crt0.o'. 'STANDARD_STARTFILE_PREFIX_2' is not searched when the - compiler is built as a cross compiler. - - -- Macro: MD_STARTFILE_PREFIX - If defined, this macro supplies an additional prefix to try after - the standard prefixes. 'MD_EXEC_PREFIX' is not searched when the - compiler is built as a cross compiler. - - -- Macro: MD_STARTFILE_PREFIX_1 - If defined, this macro supplies yet another prefix to try after the - standard prefixes. It is not searched when the compiler is built - as a cross compiler. - - -- Macro: 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 'putenv' to initialize the necessary environment - variables. - - -- Macro: LOCAL_INCLUDE_DIR - Define this macro as a C string constant if you wish to override - the standard choice of '/usr/local/include' as the default prefix - to try when searching for local header files. 'LOCAL_INCLUDE_DIR' - comes before 'NATIVE_SYSTEM_HEADER_DIR' (set in 'config.gcc', - normally '/usr/include') in the search order. - - Cross compilers do not search either '/usr/local/include' or its - replacement. - - -- Macro: NATIVE_SYSTEM_HEADER_COMPONENT - The "component" corresponding to 'NATIVE_SYSTEM_HEADER_DIR'. See - 'INCLUDE_DEFAULTS', below, for the description of components. If - you do not define this macro, no component is used. - - -- Macro: 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 'GCC_INCLUDE_DIR', 'LOCAL_INCLUDE_DIR', - 'GPLUSPLUS_INCLUDE_DIR', and 'NATIVE_SYSTEM_HEADER_DIR'. In - addition, 'GPLUSPLUS_INCLUDE_DIR' and 'GCC_INCLUDE_DIR' are defined - automatically by 'Makefile', and specify private search areas for - GCC. The directory '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 'extern '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 'GCC' or 'BINUTILS'. If the package is part of a - vendor-supplied operating system, code the component name as '0'. - - For example, here is the definition used for VAX/VMS: - - #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} \ - } - - Here is the order of prefixes tried for exec files: - - 1. Any prefixes specified by the user with '-B'. - - 2. The environment variable 'GCC_EXEC_PREFIX' or, if 'GCC_EXEC_PREFIX' - is not set and the compiler has not been installed in the - configure-time PREFIX, the location in which the compiler has - actually been installed. - - 3. The directories specified by the environment variable - 'COMPILER_PATH'. - - 4. The macro 'STANDARD_EXEC_PREFIX', if the compiler has been - installed in the configured-time PREFIX. - - 5. The location '/usr/libexec/gcc/', but only if this is a native - compiler. - - 6. The location '/usr/lib/gcc/', but only if this is a native - compiler. - - 7. The macro 'MD_EXEC_PREFIX', if defined, but only if this is a - native compiler. - - Here is the order of prefixes tried for startfiles: - - 1. Any prefixes specified by the user with '-B'. - - 2. The environment variable 'GCC_EXEC_PREFIX' or its automatically - determined value based on the installed toolchain location. - - 3. The directories specified by the environment variable - 'LIBRARY_PATH' (or port-specific name; native only, cross compilers - do not use this). - - 4. The macro 'STANDARD_EXEC_PREFIX', but only if the toolchain is - installed in the configured PREFIX or this is a native compiler. - - 5. The location '/usr/lib/gcc/', but only if this is a native - compiler. - - 6. The macro 'MD_EXEC_PREFIX', if defined, but only if this is a - native compiler. - - 7. The macro 'MD_STARTFILE_PREFIX', if defined, but only if this is a - native compiler, or we have a target system root. - - 8. The macro 'MD_STARTFILE_PREFIX_1', if defined, but only if this is - a native compiler, or we have a target system root. - - 9. The macro 'STANDARD_STARTFILE_PREFIX', with any sysroot - modifications. If this path is relative it will be prefixed by - 'GCC_EXEC_PREFIX' and the machine suffix or 'STANDARD_EXEC_PREFIX' - and the machine suffix. - - 10. The macro 'STANDARD_STARTFILE_PREFIX_1', but only if this is a - native compiler, or we have a target system root. The default for - this macro is '/lib/'. - - 11. The macro 'STANDARD_STARTFILE_PREFIX_2', but only if this is a - native compiler, or we have a target system root. The default for - this macro is '/usr/lib/'. - - -File: gccint.info, Node: Run-time Target, Next: Per-Function Data, Prev: Driver, Up: Target Macros - -17.3 Run-time Target Specification -================================== - -Here are run-time target specifications. - - -- Macro: 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 'builtin_define', 'builtin_define_std' and - '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. - - 'builtin_assert' takes a string in the form you pass to the - command-line option '-A', such as 'cpu=mips', and creates the - assertion. 'builtin_define' takes a string in the form accepted by - option '-D' and unconditionally defines the macro. - - 'builtin_define_std' takes a string representing the name of an - object-like macro. If it doesn't lie in the user's namespace, - '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 'unix' defines '__unix', '__unix__' and possibly - 'unix'; passing '_mips' defines '__mips', '__mips__' and possibly - '_mips', and passing '_ABI64' defines only '_ABI64'. - - You can also test for the C dialect being compiled. The variable - 'c_language' is set to one of 'clk_c', 'clk_cplusplus' or - 'clk_objective_c'. Note that if we are preprocessing assembler, - this variable will be 'clk_c' but the function-like macro - '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 'flag_iso' can be used. The function-like macro - 'preprocessing_trad_p()' can be used to check for traditional - preprocessing. - - -- Macro: TARGET_OS_CPP_BUILTINS () - Similarly to 'TARGET_CPU_CPP_BUILTINS' but this macro is optional - and is used for the target operating system instead. - - -- Macro: TARGET_OBJFMT_CPP_BUILTINS () - Similarly to 'TARGET_CPU_CPP_BUILTINS' but this macro is optional - and is used for the target object format. 'elfos.h' uses this - macro to define '__ELF__', so you probably do not need to define it - yourself. - - -- Variable: extern int target_flags - This variable is declared in 'options.h', which is included before - any target-specific headers. - - -- Common Target Hook: int TARGET_DEFAULT_TARGET_FLAGS - This variable specifies the initial value of 'target_flags'. Its - default setting is 0. - - -- Common Target Hook: bool TARGET_HANDLE_OPTION (struct gcc_options - *OPTS, struct gcc_options *OPTS_SET, const struct - cl_decoded_option *DECODED, location_t LOC) - This hook is called whenever the user specifies one of the - target-specific options described by the '.opt' definition files - (*note 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. - - DECODED specifies the option and its arguments. OPTS and OPTS_SET - are the 'gcc_options' structures to be used for storing option - state, and LOC is the location at which the option was passed - ('UNKNOWN_LOCATION' except for options passed via attributes). - - -- C Target Hook: bool TARGET_HANDLE_C_OPTION (size_t CODE, const char - *ARG, int VALUE) - This target hook is called whenever the user specifies one of the - target-specific C language family options described by the '.opt' - definition files(*note Options::). It has the opportunity to do - some option-specific processing and should return true if the - option is valid. The arguments are like for - 'TARGET_HANDLE_OPTION'. The default definition does nothing but - return false. - - In general, you should use 'TARGET_HANDLE_OPTION' to handle - options. However, if processing an option requires routines that - are only available in the C (and related language) front ends, then - you should use 'TARGET_HANDLE_C_OPTION' instead. - - -- C Target Hook: tree TARGET_OBJC_CONSTRUCT_STRING_OBJECT (tree - STRING) - Targets may provide a string object type that can be used within - and between C, C++ and their respective Objective-C dialects. A - string object might, for example, embed encoding and length - information. These objects are considered opaque to the compiler - and handled as references. An ideal implementation makes the - composition of the string object match that of the Objective-C - 'NSString' ('NXString' for GNUStep), allowing efficient - interworking between C-only and Objective-C code. If a target - implements string objects then this hook should return a reference - to such an object constructed from the normal 'C' string - representation provided in STRING. At present, the hook is used by - Objective-C only, to obtain a common-format string object when the - target provides one. - - -- C Target Hook: void TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE - (const char *CLASSNAME) - Declare that Objective C class CLASSNAME is referenced by the - current TU. - - -- C Target Hook: void TARGET_OBJC_DECLARE_CLASS_DEFINITION (const char - *CLASSNAME) - Declare that Objective C class CLASSNAME is defined by the current - TU. - - -- C Target Hook: bool TARGET_STRING_OBJECT_REF_TYPE_P (const_tree - STRINGREF) - If a target implements string objects then this hook should return - 'true' if STRINGREF is a valid reference to such an object. - - -- C Target Hook: void TARGET_CHECK_STRING_OBJECT_FORMAT_ARG (tree - FORMAT_ARG, tree ARGS_LIST) - If a target implements string objects then this hook should should - provide a facility to check the function arguments in ARGS_LIST - against the format specifiers in FORMAT_ARG where the type of - FORMAT_ARG is one recognized as a valid string reference type. - - -- Target Hook: void TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE (void) - This target function is similar to the hook - 'TARGET_OPTION_OVERRIDE' but is called when the optimize level is - changed via an attribute or pragma or when it is reset at the end - of the code affected by the attribute or pragma. It is not called - at the beginning of compilation when 'TARGET_OPTION_OVERRIDE' is - called so if you want to perform these actions then, you should - have 'TARGET_OPTION_OVERRIDE' call - 'TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE'. - - -- Macro: C_COMMON_OVERRIDE_OPTIONS - This is similar to the 'TARGET_OPTION_OVERRIDE' hook 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. - - -- Common Target Hook: const struct default_options * - TARGET_OPTION_OPTIMIZATION_TABLE - Some machines may desire to change what optimizations are performed - for various optimization levels. This variable, if defined, - describes options to enable at particular sets of optimization - levels. These options are processed once just after the - optimization level is determined and before the remainder of the - command options have been parsed, so may be overridden by other - options passed explicitly. - - This processing is run once at program startup and when the - optimization options are changed via '#pragma GCC optimize' or by - using the 'optimize' attribute. - - -- Common Target Hook: void TARGET_OPTION_INIT_STRUCT (struct - gcc_options *OPTS) - Set target-dependent initial values of fields in OPTS. - - -- Common Target Hook: void TARGET_OPTION_DEFAULT_PARAMS (void) - Set target-dependent default values for '--param' settings, using - calls to 'set_default_param_value'. - - -- Macro: SWITCHABLE_TARGET - Some targets need to switch between substantially different - subtargets during compilation. For example, the MIPS target has - one subtarget for the traditional MIPS architecture and another for - MIPS16. Source code can switch between these two subarchitectures - using the 'mips16' and 'nomips16' attributes. - - Such subtargets can differ in things like the set of available - registers, the set of available instructions, the costs of various - operations, and so on. GCC caches a lot of this type of - information in global variables, and recomputing them for each - subtarget takes a significant amount of time. The compiler - therefore provides a facility for maintaining several versions of - the global variables and quickly switching between them; see - 'target-globals.h' for details. - - Define this macro to 1 if your target needs this facility. The - default is 0. - - -- Target Hook: bool TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P - (void) - Returns true if the target supports IEEE 754 floating-point - exceptions and rounding modes, false otherwise. This is intended - to relate to the 'float' and 'double' types, but not necessarily - 'long double'. By default, returns true if the 'adddf3' - instruction pattern is available and false otherwise, on the - assumption that hardware floating point supports exceptions and - rounding modes but software floating point does not. - - -File: gccint.info, Node: Per-Function Data, Next: Storage Layout, Prev: Run-time Target, Up: Target Macros - -17.4 Defining data structures for per-function information. -=========================================================== - -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 'struct function' which contains -all of the data specific to an individual function. This structure -contains a field called 'machine' whose type is '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 -'struct machine_function' and also the macro 'INIT_EXPANDERS'. This -macro should be used to initialize the function pointer -'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 '__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 'save_machine_status' and -'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. - - -- Macro: 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 'init_machine_status'. - - -- Variable: void (*)(struct function *) init_machine_status - If this function pointer is non-'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 'struct - function' structure. It is intended that this would be used to - initialize the 'machine' of that structure. - - 'struct machine_function' structures are expected to be freed by - GC. Generally, any memory that they reference must be allocated by - using GC allocation, including the structure itself. - - -File: gccint.info, Node: Storage Layout, Next: Type Layout, Prev: Per-Function Data, Up: Target Macros - -17.5 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 'target_flags'. -*Note Run-time Target::. - - -- Macro: 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 'BYTES_BIG_ENDIAN'. - - -- Macro: 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. - - -- Macro: 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; see 'REG_WORDS_BIG_ENDIAN' if - the order of words in memory is not the same as the order in - registers. This macro need not be a constant. - - -- Macro: REG_WORDS_BIG_ENDIAN - On some machines, the order of words in a multiword object differs - between registers in memory. In such a situation, define this - macro to describe the order of words in a register. The macro - 'WORDS_BIG_ENDIAN' controls the order of words in memory. - - -- Macro: FLOAT_WORDS_BIG_ENDIAN - Define this macro to have the value 1 if 'DFmode', 'XFmode' or - '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. - - -- Macro: BITS_PER_WORD - Number of bits in a word. If you do not define this macro, the - default is 'BITS_PER_UNIT * UNITS_PER_WORD'. - - -- Macro: MAX_BITS_PER_WORD - Maximum number of bits in a word. If this is undefined, the - default is 'BITS_PER_WORD'. Otherwise, it is the constant value - that is the largest value that 'BITS_PER_WORD' can have at - run-time. - - -- Macro: 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. - - -- Macro: MIN_UNITS_PER_WORD - Minimum number of units in a word. If this is undefined, the - default is 'UNITS_PER_WORD'. Otherwise, it is the constant value - that is the smallest value that 'UNITS_PER_WORD' can have at - run-time. - - -- Macro: POINTER_SIZE - Width of a pointer, in bits. You must specify a value no wider - than the width of 'Pmode'. If it is not equal to the width of - 'Pmode', you must define 'POINTERS_EXTEND_UNSIGNED'. If you do not - specify a value the default is 'BITS_PER_WORD'. - - -- Macro: POINTERS_EXTEND_UNSIGNED - A C expression that determines how pointers should be extended from - 'ptr_mode' to either 'Pmode' or 'word_mode'. It is greater than - zero if pointers should be zero-extended, zero if they should be - sign-extended, and negative if some other sort of conversion is - needed. In the last case, the extension is done by the target's - 'ptr_extend' instruction. - - You need not define this macro if the 'ptr_mode', 'Pmode' and - 'word_mode' are all the same width. - - -- Macro: PROMOTE_MODE (M, UNSIGNEDP, TYPE) - A macro to update M and UNSIGNEDP when an object whose type is TYPE - and which has the specified mode and signedness is to be stored in - a register. This macro is only called when TYPE is a scalar type. - - On most RISC machines, which only have operations that operate on a - full register, define this macro to set M to 'word_mode' if M is an - integer mode narrower than '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 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 UNSIGNEDP according to which kind of extension is more - efficient. - - Do not define this macro if it would never modify M. - - -- Target Hook: enum machine_mode TARGET_PROMOTE_FUNCTION_MODE - (const_tree TYPE, enum machine_mode MODE, int *PUNSIGNEDP, - const_tree FUNTYPE, int FOR_RETURN) - Like 'PROMOTE_MODE', but it is applied to outgoing function - arguments or function return values. The target hook should return - the new mode and possibly change '*PUNSIGNEDP' if the promotion - should change signedness. This function is called only for scalar - _or pointer_ types. - - FOR_RETURN allows to distinguish the promotion of arguments and - return values. If it is '1', a return value is being promoted and - 'TARGET_FUNCTION_VALUE' must perform the same promotions done here. - If it is '2', the returned mode should be that of the register in - which an incoming parameter is copied, or the outgoing result is - computed; then the hook should return the same mode as - 'promote_mode', though the signedness may be different. - - TYPE can be NULL when promoting function arguments of libcalls. - - The default is to not promote arguments and return values. You can - also define the hook to - 'default_promote_function_mode_always_promote' if you would like to - apply the same rules given by 'PROMOTE_MODE'. - - -- Macro: 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. - - -- Macro: 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 'PREFERRED_STACK_BOUNDARY' is not - defined. On most machines, this should be the same as - 'PARM_BOUNDARY'. - - -- Macro: 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 - 'STACK_BOUNDARY'. - - -- Macro: INCOMING_STACK_BOUNDARY - Define this macro if the incoming stack boundary may be different - from 'PREFERRED_STACK_BOUNDARY'. This macro must evaluate to a - value equal to or larger than 'STACK_BOUNDARY'. - - -- Macro: FUNCTION_BOUNDARY - Alignment required for a function entry point, in bits. - - -- Macro: BIGGEST_ALIGNMENT - Biggest alignment that any data type can require on this machine, - in bits. Note that this is not the biggest alignment that is - supported, just the biggest alignment that, when violated, may - cause a fault. - - -- Macro: MALLOC_ABI_ALIGNMENT - Alignment, in bits, a C conformant malloc implementation has to - provide. If not defined, the default value is 'BITS_PER_WORD'. - - -- Macro: ATTRIBUTE_ALIGNED_VALUE - Alignment used by the '__attribute__ ((aligned))' construct. If - not defined, the default value is 'BIGGEST_ALIGNMENT'. - - -- Macro: 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 'BITS_PER_UNIT', - but may be larger on machines that don't have byte or half-word - store operations. - - -- Macro: BIGGEST_FIELD_ALIGNMENT - Biggest alignment that any structure or union field can require on - this machine, in bits. If defined, this overrides - 'BIGGEST_ALIGNMENT' for structure and union fields only, unless the - field alignment has been set by the '__attribute__ ((aligned (N)))' - construct. - - -- Macro: ADJUST_FIELD_ALIGN (FIELD, COMPUTED) - An expression for the alignment of a structure field FIELD if the - alignment computed in the usual way (including applying of - 'BIGGEST_ALIGNMENT' and 'BIGGEST_FIELD_ALIGNMENT' to the alignment) - is COMPUTED. It overrides alignment only if the field alignment - has not been set by the '__attribute__ ((aligned (N)))' construct. - - -- Macro: MAX_STACK_ALIGNMENT - Biggest stack alignment guaranteed by the backend. Use this macro - to specify the maximum alignment of a variable on stack. - - If not defined, the default value is 'STACK_BOUNDARY'. - - -- Macro: 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 '__attribute__ ((aligned (N)))' construct. If - not defined, the default value is 'BIGGEST_ALIGNMENT'. - - On systems that use ELF, the default (in 'config/elfos.h') is the - largest supported 32-bit ELF section alignment representable on a - 32-bit host e.g. '(((unsigned HOST_WIDEST_INT) 1 << 28) * 8)'. On - 32-bit ELF the largest supported section alignment in bits is - '(0x80000000 * 8)', but this is not representable on 32-bit hosts. - - -- Macro: DATA_ALIGNMENT (TYPE, BASIC-ALIGN) - If defined, a C expression to compute the alignment for a variable - in the static store. TYPE is the data type, and 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 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. Another is to cause - character arrays to be word-aligned so that 'strcpy' calls that - copy constants to character arrays can be done inline. - - -- Macro: DATA_ABI_ALIGNMENT (TYPE, BASIC-ALIGN) - Similar to 'DATA_ALIGNMENT', but for the cases where the ABI - mandates some alignment increase, instead of optimization only - purposes. E.g. AMD x86-64 psABI says that variables with array - type larger than 15 bytes must be aligned to 16 byte boundaries. - - If this macro is not defined, then BASIC-ALIGN is used. - - -- Macro: CONSTANT_ALIGNMENT (CONSTANT, BASIC-ALIGN) - If defined, a C expression to compute the alignment given to a - constant that is being placed in memory. CONSTANT is the constant - and 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 BASIC-ALIGN is used. - - The typical use of this macro is to increase alignment for string - constants to be word aligned so that 'strcpy' calls that copy - constants can be done inline. - - -- Macro: LOCAL_ALIGNMENT (TYPE, BASIC-ALIGN) - If defined, a C expression to compute the alignment for a variable - in the local store. TYPE is the data type, and 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 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. - - If the value of this macro has a type, it should be an unsigned - type. - - -- Target Hook: HOST_WIDE_INT TARGET_VECTOR_ALIGNMENT (const_tree TYPE) - This hook can be used to define the alignment for a vector of type - TYPE, in order to comply with a platform ABI. The default is to - require natural alignment for vector types. The alignment returned - by this hook must be a power-of-two multiple of the default - alignment of the vector element type. - - -- Macro: STACK_SLOT_ALIGNMENT (TYPE, MODE, BASIC-ALIGN) - If defined, a C expression to compute the alignment for stack slot. - TYPE is the data type, MODE is the widest mode available, and - BASIC-ALIGN is the alignment that the slot would ordinarily have. - The value of this macro is used instead of that alignment to align - the slot. - - If this macro is not defined, then BASIC-ALIGN is used when TYPE is - 'NULL'. Otherwise, 'LOCAL_ALIGNMENT' will be used. - - This macro is to set alignment of stack slot to the maximum - alignment of all possible modes which the slot may have. - - If the value of this macro has a type, it should be an unsigned - type. - - -- Macro: LOCAL_DECL_ALIGNMENT (DECL) - If defined, a C expression to compute the alignment for a local - variable DECL. - - If this macro is not defined, then 'LOCAL_ALIGNMENT (TREE_TYPE - (DECL), DECL_ALIGN (DECL))' is used. - - One use of this macro is to increase alignment of medium-size data - to make it all fit in fewer cache lines. - - If the value of this macro has a type, it should be an unsigned - type. - - -- Macro: MINIMUM_ALIGNMENT (EXP, MODE, ALIGN) - If defined, a C expression to compute the minimum required - alignment for dynamic stack realignment purposes for EXP (a type or - decl), MODE, assuming normal alignment ALIGN. - - If this macro is not defined, then ALIGN will be used. - - -- Macro: EMPTY_FIELD_BOUNDARY - Alignment in bits to be given to a structure bit-field that follows - an empty field such as 'int : 0;'. - - If 'PCC_BITFIELD_TYPE_MATTERS' is true, it overrides this macro. - - -- Macro: 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 - 'BITS_PER_UNIT'. - - -- Macro: 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. - - -- Macro: 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 ('int', - '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 - '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 'insv', 'extv', - and 'extzv' insns that can directly reference memory. - - The other known way of making bit-fields work is to define - 'STRUCTURE_SIZE_BOUNDARY' as large as 'BIGGEST_ALIGNMENT'. Then - every structure can be accessed with fullwords. - - Unless the machine has bit-field instructions or you define - 'STRUCTURE_SIZE_BOUNDARY' that way, you must define - '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: - - 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); - } - - If this prints 2 and 5, then the compiler's behavior is what you - would get from 'PCC_BITFIELD_TYPE_MATTERS'. - - -- Macro: BITFIELD_NBYTES_LIMITED - Like 'PCC_BITFIELD_TYPE_MATTERS' except that its effect is limited - to aligning a bit-field within the structure. - - -- Target Hook: bool TARGET_ALIGN_ANON_BITFIELD (void) - When '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. - - -- Target Hook: bool TARGET_NARROW_VOLATILE_BITFIELD (void) - This target hook should return 'true' if accesses to volatile - bitfields should use the narrowest mode possible. It should return - 'false' if these accesses should use the bitfield container type. - - The default is 'false'. - - -- Target Hook: bool TARGET_MEMBER_TYPE_FORCES_BLK (const_tree FIELD, - enum machine_mode MODE) - Return true if a structure, union or array containing FIELD should - be accessed using 'BLKMODE'. - - If FIELD is the only field in the structure, MODE is its mode, - otherwise MODE is VOIDmode. 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. - - -- Macro: ROUND_TYPE_ALIGN (TYPE, COMPUTED, SPECIFIED) - Define this macro as an expression for the alignment of a type - (given by TYPE as a tree node) if the alignment computed in the - usual way is COMPUTED and the alignment explicitly specified was - SPECIFIED. - - The default is to use SPECIFIED if it is larger; otherwise, use the - smaller of COMPUTED and 'BIGGEST_ALIGNMENT' - - -- Macro: 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, - 'GET_MODE_BITSIZE (DImode)' is assumed. - - -- Macro: STACK_SAVEAREA_MODE (SAVE_LEVEL) - If defined, an expression of type 'enum machine_mode' that - specifies the mode of the save area operand of a 'save_stack_LEVEL' - named pattern (*note Standard Names::). SAVE_LEVEL is one of - 'SAVE_BLOCK', 'SAVE_FUNCTION', or '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 'Pmode'. You - would most commonly define this macro if the 'save_stack_LEVEL' - patterns need to support both a 32- and a 64-bit mode. - - -- Macro: STACK_SIZE_MODE - If defined, an expression of type 'enum machine_mode' that - specifies the mode of the size increment operand of an - 'allocate_stack' named pattern (*note Standard Names::). - - You need not define this macro if it always returns 'word_mode'. - You would most commonly define this macro if the 'allocate_stack' - pattern needs to support both a 32- and a 64-bit mode. - - -- Target Hook: enum machine_mode TARGET_LIBGCC_CMP_RETURN_MODE (void) - This target hook should return the mode to be used for the return - value of compare instructions expanded to libgcc calls. If not - defined 'word_mode' is returned which is the right choice for a - majority of targets. - - -- Target Hook: enum machine_mode TARGET_LIBGCC_SHIFT_COUNT_MODE (void) - This target hook should return the mode to be used for the shift - count operand of shift instructions expanded to libgcc calls. If - not defined 'word_mode' is returned which is the right choice for a - majority of targets. - - -- Target Hook: enum machine_mode TARGET_UNWIND_WORD_MODE (void) - Return machine mode to be used for '_Unwind_Word' type. The - default is to use 'word_mode'. - - -- Macro: ROUND_TOWARDS_ZERO - If defined, this macro should be true if the prevailing rounding - mode is towards zero. - - Defining this macro only affects the way 'libgcc.a' emulates - floating-point arithmetic. - - Not defining this macro is equivalent to returning zero. - - -- Macro: LARGEST_EXPONENT_IS_NORMAL (SIZE) - This macro should return true if floats with SIZE bits do not have - a NaN or infinity representation, but use the largest exponent for - normal numbers instead. - - Defining this macro only affects the way 'libgcc.a' emulates - floating-point arithmetic. - - The default definition of this macro returns false for all sizes. - - -- Target Hook: bool TARGET_MS_BITFIELD_LAYOUT_P (const_tree - RECORD_TYPE) - This target hook returns 'true' if bit-fields in the given - 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 '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 '__attribute__((packed))' are used, the - latter will take precedence. If '__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. - - -- Target Hook: bool TARGET_DECIMAL_FLOAT_SUPPORTED_P (void) - Returns true if the target supports decimal floating point. - - -- Target Hook: bool TARGET_FIXED_POINT_SUPPORTED_P (void) - Returns true if the target supports fixed-point arithmetic. - - -- Target Hook: void TARGET_EXPAND_TO_RTL_HOOK (void) - This hook is called just before expansion into rtl, allowing the - target to perform additional initializations or analysis before the - expansion. For example, the rs6000 port uses it to allocate a - scratch stack slot for use in copying SDmode values between memory - and floating point registers whenever the function being expanded - has any SDmode usage. - - -- Target Hook: void TARGET_INSTANTIATE_DECLS (void) - This hook allows the backend to perform additional instantiations - on rtl that are not actually in any insns yet, but will be later. - - -- Target Hook: const char * TARGET_MANGLE_TYPE (const_tree 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 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 'NULL' for all such types, as well as arguments it - does not recognize. If the return value is not 'NULL', it must - point to a statically-allocated string constant. - - Target-specific fundamental types might be new fundamental types or - qualified versions of ordinary fundamental types. Encode new - fundamental types as 'u N NAME', where NAME is the name used for - the type in source code, and N is the length of NAME in decimal. - Encode qualified versions of ordinary types as 'U N NAME CODE', - where NAME is the name used for the type qualifier in source code, - N is the length of NAME as above, and CODE is the code used to - represent the unqualified version of this type. (See - 'write_builtin_type' in 'cp/mangle.c' for the list of codes.) In - both cases the spaces are for clarity; do not include any spaces in - your string. - - 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 - 'TYPE_MAIN_VARIANT' before mangling. - - The default version of this hook always returns 'NULL', which is - appropriate for a target that does not define any new fundamental - types. - - -File: gccint.info, Node: Type Layout, Next: Registers, Prev: Storage Layout, Up: Target Macros - -17.6 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. - - -- Macro: INT_TYPE_SIZE - A C expression for the size in bits of the type 'int' on the target - machine. If you don't define this, the default is one word. - - -- Macro: SHORT_TYPE_SIZE - A C expression for the size in bits of the type '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.) - - -- Macro: LONG_TYPE_SIZE - A C expression for the size in bits of the type 'long' on the - target machine. If you don't define this, the default is one word. - - -- Macro: ADA_LONG_TYPE_SIZE - On some machines, the size used for the Ada equivalent of the type - '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 'LONG_TYPE_SIZE'. - - -- Macro: LONG_LONG_TYPE_SIZE - A C expression for the size in bits of the type '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. - - -- Macro: CHAR_TYPE_SIZE - A C expression for the size in bits of the type 'char' on the - target machine. If you don't define this, the default is - 'BITS_PER_UNIT'. - - -- Macro: BOOL_TYPE_SIZE - A C expression for the size in bits of the C++ type 'bool' and C99 - type '_Bool' on the target machine. If you don't define this, and - you probably shouldn't, the default is 'CHAR_TYPE_SIZE'. - - -- Macro: FLOAT_TYPE_SIZE - A C expression for the size in bits of the type 'float' on the - target machine. If you don't define this, the default is one word. - - -- Macro: DOUBLE_TYPE_SIZE - A C expression for the size in bits of the type 'double' on the - target machine. If you don't define this, the default is two - words. - - -- Macro: LONG_DOUBLE_TYPE_SIZE - A C expression for the size in bits of the type 'long double' on - the target machine. If you don't define this, the default is two - words. - - -- Macro: SHORT_FRACT_TYPE_SIZE - A C expression for the size in bits of the type 'short _Fract' on - the target machine. If you don't define this, the default is - 'BITS_PER_UNIT'. - - -- Macro: FRACT_TYPE_SIZE - A C expression for the size in bits of the type '_Fract' on the - target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 2'. - - -- Macro: LONG_FRACT_TYPE_SIZE - A C expression for the size in bits of the type 'long _Fract' on - the target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 4'. - - -- Macro: LONG_LONG_FRACT_TYPE_SIZE - A C expression for the size in bits of the type 'long long _Fract' - on the target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 8'. - - -- Macro: SHORT_ACCUM_TYPE_SIZE - A C expression for the size in bits of the type 'short _Accum' on - the target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 2'. - - -- Macro: ACCUM_TYPE_SIZE - A C expression for the size in bits of the type '_Accum' on the - target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 4'. - - -- Macro: LONG_ACCUM_TYPE_SIZE - A C expression for the size in bits of the type 'long _Accum' on - the target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 8'. - - -- Macro: LONG_LONG_ACCUM_TYPE_SIZE - A C expression for the size in bits of the type 'long long _Accum' - on the target machine. If you don't define this, the default is - 'BITS_PER_UNIT * 16'. - - -- Macro: LIBGCC2_LONG_DOUBLE_TYPE_SIZE - Define this macro if 'LONG_DOUBLE_TYPE_SIZE' is not constant or if - you want routines in 'libgcc2.a' for a size other than - 'LONG_DOUBLE_TYPE_SIZE'. If you don't define this, the default is - 'LONG_DOUBLE_TYPE_SIZE'. - - -- Macro: LIBGCC2_HAS_DF_MODE - Define this macro if neither 'DOUBLE_TYPE_SIZE' nor - 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 'DFmode' but you want 'DFmode' - routines in 'libgcc2.a' anyway. If you don't define this and - either 'DOUBLE_TYPE_SIZE' or 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 64 - then the default is 1, otherwise it is 0. - - -- Macro: LIBGCC2_HAS_XF_MODE - Define this macro if 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is not - 'XFmode' but you want 'XFmode' routines in 'libgcc2.a' anyway. If - you don't define this and 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 80 - then the default is 1, otherwise it is 0. - - -- Macro: LIBGCC2_HAS_TF_MODE - Define this macro if 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is not - 'TFmode' but you want 'TFmode' routines in 'libgcc2.a' anyway. If - you don't define this and 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 128 - then the default is 1, otherwise it is 0. - - -- Macro: LIBGCC2_GNU_PREFIX - This macro corresponds to the 'TARGET_LIBFUNC_GNU_PREFIX' target - hook and should be defined if that hook is overriden to be true. - It causes function names in libgcc to be changed to use a '__gnu_' - prefix for their name rather than the default '__'. A port which - uses this macro should also arrange to use 't-gnu-prefix' in the - libgcc 'config.host'. - - -- Macro: SF_SIZE - -- Macro: DF_SIZE - -- Macro: XF_SIZE - -- Macro: TF_SIZE - Define these macros to be the size in bits of the mantissa of - 'SFmode', 'DFmode', 'XFmode' and 'TFmode' values, if the defaults - in 'libgcc2.h' are inappropriate. By default, 'FLT_MANT_DIG' is - used for 'SF_SIZE', 'LDBL_MANT_DIG' for 'XF_SIZE' and 'TF_SIZE', - and 'DBL_MANT_DIG' or 'LDBL_MANT_DIG' for 'DF_SIZE' according to - whether 'DOUBLE_TYPE_SIZE' or 'LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is - 64. - - -- Macro: TARGET_FLT_EVAL_METHOD - A C expression for the value for 'FLT_EVAL_METHOD' in '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 - 'FLT_EVAL_METHOD' will be zero. - - -- Macro: 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 - 'LONG_DOUBLE_TYPE_SIZE'. If you do not define this macro, the - value of 'LONG_DOUBLE_TYPE_SIZE' is the default. - - -- Macro: DEFAULT_SIGNED_CHAR - An expression whose value is 1 or 0, according to whether the type - 'char' should be signed or unsigned by default. The user can - always override this default with the options '-fsigned-char' and - '-funsigned-char'. - - -- Target Hook: bool TARGET_DEFAULT_SHORT_ENUMS (void) - This target hook should return true if the compiler should give an - '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 - 'enum' types should be allocated like 'int'. - - The default is to return false. - - -- Macro: SIZE_TYPE - A C expression for a string describing the name of the data type to - use for size values. The typedef name '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 'unsigned' if - appropriate, and finally 'int'. The string must exactly match one - of the data type names defined in the function - 'c_common_nodes_and_builtins' in the file 'c-family/c-common.c'. - You may not omit 'int' or change the order--that would cause the - compiler to crash on startup. - - If you don't define this macro, the default is '"long unsigned - int"'. - - -- Macro: SIZETYPE - GCC defines internal types ('sizetype', 'ssizetype', 'bitsizetype' - and 'sbitsizetype') for expressions dealing with size. This macro - is a C expression for a string describing the name of the data type - from which the precision of 'sizetype' is extracted. - - The string has the same restrictions as 'SIZE_TYPE' string. - - If you don't define this macro, the default is 'SIZE_TYPE'. - - -- Macro: 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 - 'ptrdiff_t' is defined using the contents of the string. See - 'SIZE_TYPE' above for more information. - - If you don't define this macro, the default is '"long int"'. - - -- Macro: WCHAR_TYPE - A C expression for a string describing the name of the data type to - use for wide characters. The typedef name 'wchar_t' is defined - using the contents of the string. See 'SIZE_TYPE' above for more - information. - - If you don't define this macro, the default is '"int"'. - - -- Macro: WCHAR_TYPE_SIZE - A C expression for the size in bits of the data type for wide - characters. This is used in 'cpp', which cannot make use of - 'WCHAR_TYPE'. - - -- Macro: WINT_TYPE - A C expression for a string describing the name of the data type to - use for wide characters passed to 'printf' and returned from - 'getwc'. The typedef name 'wint_t' is defined using the contents - of the string. See 'SIZE_TYPE' above for more information. - - If you don't define this macro, the default is '"unsigned int"'. - - -- Macro: 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 'intmax_t' is defined using the - contents of the string. See 'SIZE_TYPE' above for more - information. - - If you don't define this macro, the default is the first of - '"int"', '"long int"', or '"long long int"' that has as much - precision as 'long long int'. - - -- Macro: 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 'uintmax_t' is defined using the - contents of the string. See 'SIZE_TYPE' above for more - information. - - If you don't define this macro, the default is the first of - '"unsigned int"', '"long unsigned int"', or '"long long unsigned - int"' that has as much precision as 'long long unsigned int'. - - -- Macro: SIG_ATOMIC_TYPE - -- Macro: INT8_TYPE - -- Macro: INT16_TYPE - -- Macro: INT32_TYPE - -- Macro: INT64_TYPE - -- Macro: UINT8_TYPE - -- Macro: UINT16_TYPE - -- Macro: UINT32_TYPE - -- Macro: UINT64_TYPE - -- Macro: INT_LEAST8_TYPE - -- Macro: INT_LEAST16_TYPE - -- Macro: INT_LEAST32_TYPE - -- Macro: INT_LEAST64_TYPE - -- Macro: UINT_LEAST8_TYPE - -- Macro: UINT_LEAST16_TYPE - -- Macro: UINT_LEAST32_TYPE - -- Macro: UINT_LEAST64_TYPE - -- Macro: INT_FAST8_TYPE - -- Macro: INT_FAST16_TYPE - -- Macro: INT_FAST32_TYPE - -- Macro: INT_FAST64_TYPE - -- Macro: UINT_FAST8_TYPE - -- Macro: UINT_FAST16_TYPE - -- Macro: UINT_FAST32_TYPE - -- Macro: UINT_FAST64_TYPE - -- Macro: INTPTR_TYPE - -- Macro: UINTPTR_TYPE - C expressions for the standard types 'sig_atomic_t', 'int8_t', - 'int16_t', 'int32_t', 'int64_t', 'uint8_t', 'uint16_t', 'uint32_t', - 'uint64_t', 'int_least8_t', 'int_least16_t', 'int_least32_t', - 'int_least64_t', 'uint_least8_t', 'uint_least16_t', - 'uint_least32_t', 'uint_least64_t', 'int_fast8_t', 'int_fast16_t', - 'int_fast32_t', 'int_fast64_t', 'uint_fast8_t', 'uint_fast16_t', - 'uint_fast32_t', 'uint_fast64_t', 'intptr_t', and 'uintptr_t'. See - 'SIZE_TYPE' above for more information. - - If any of these macros evaluates to a null pointer, the - corresponding type is not supported; if GCC is configured to - provide '<stdint.h>' in such a case, the header provided may not - conform to C99, depending on the type in question. The defaults - for all of these macros are null pointers. - - -- Macro: TARGET_PTRMEMFUNC_VBIT_LOCATION - The C++ compiler represents a pointer-to-member-function with a - struct that looks like: - - struct { - union { - void (*fn)(); - ptrdiff_t vtable_index; - }; - ptrdiff_t delta; - }; - - 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 'delta' field, and shift the remainder of the 'delta' field - to the left. - - GCC will automatically make the right selection about where to - store this bit using the 'FUNCTION_BOUNDARY' setting for your - platform. However, some platforms such as ARM/Thumb have - '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 '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 'FUNCTION_BOUNDARY', GCC will automatically define - this macro to 'ptrmemfunc_vbit_in_pfn'. - - -- Macro: 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. - - -- Macro: 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. */ - - -- Macro: 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 'TARGET_VTABLE_ENTRY_ALIGN'), set this to - the number of words in each data entry. - - -File: gccint.info, Node: Registers, Next: Register Classes, Prev: Type Layout, Up: Target Macros - -17.7 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 *note Register Classes::. For -information on using registers to access a stack frame, see *note Frame -Registers::. For passing values in registers, see *note Register -Arguments::. For returning values in registers, see *note 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. - - -File: gccint.info, Node: Register Basics, Next: Allocation Order, Up: Registers - -17.7.1 Basic Characteristics of Registers ------------------------------------------ - -Registers have various characteristics. - - -- Macro: FIRST_PSEUDO_REGISTER - Number of hardware registers known to the compiler. They receive - numbers 0 through 'FIRST_PSEUDO_REGISTER-1'; thus, the first pseudo - register's number really is assigned the number - 'FIRST_PSEUDO_REGISTER'. - - -- Macro: FIXED_REGISTERS - 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 Nth number is 1 if - register 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 - 'CONDITIONAL_REGISTER_USAGE', or by the user with the command - options '-ffixed-REG', '-fcall-used-REG' and '-fcall-saved-REG'. - - -- Macro: CALL_USED_REGISTERS - Like '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 '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. - - -- Macro: CALL_REALLY_USED_REGISTERS - Like 'CALL_USED_REGISTERS' except this macro doesn't require that - the entire set of 'FIXED_REGISTERS' be included. - ('CALL_USED_REGISTERS' must be a superset of 'FIXED_REGISTERS'). - This macro is optional. If not specified, it defaults to the value - of 'CALL_USED_REGISTERS'. - - -- Macro: HARD_REGNO_CALL_PART_CLOBBERED (REGNO, MODE) - A C expression that is nonzero if it is not permissible to store a - value of mode MODE in hard register number 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. - - -- Target Hook: void TARGET_CONDITIONAL_REGISTER_USAGE (void) - This hook may conditionally modify five variables 'fixed_regs', - 'call_used_regs', 'global_regs', 'reg_names', and - 'reg_class_contents', to take into account any dependence of these - register sets on target flags. The first three of these are of - type 'char []' (interpreted as Boolean vectors). 'global_regs' is - a 'const char *[]', and 'reg_class_contents' is a 'HARD_REG_SET'. - Before the macro is called, 'fixed_regs', 'call_used_regs', - 'reg_class_contents', and 'reg_names' have been initialized from - 'FIXED_REGISTERS', 'CALL_USED_REGISTERS', 'REG_CLASS_CONTENTS', and - 'REGISTER_NAMES', respectively. 'global_regs' has been cleared, - and any '-ffixed-REG', '-fcall-used-REG' and '-fcall-saved-REG' - command options have been applied. - - 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 - 'fixed_regs' and 'call_used_regs' to 1 for each of the registers in - the classes which should not be used by GCC. Also define the macro - 'REG_CLASS_FROM_LETTER' / 'REG_CLASS_FROM_CONSTRAINT' to return - '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 '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.) - - -- Macro: INCOMING_REGNO (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 OUT as seen by the - calling function. Return OUT if register number OUT is not an - outbound register. - - -- Macro: OUTGOING_REGNO (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 IN as seen by the - called function. Return IN if register number IN is not an inbound - register. - - -- Macro: LOCAL_REGNO (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. - - -- Macro: PC_REGNUM - If the program counter has a register number, define this as that - register number. Otherwise, do not define it. - - -File: gccint.info, Node: Allocation Order, Next: Values in Registers, Prev: Register Basics, Up: Registers - -17.7.2 Order of Allocation of Registers ---------------------------------------- - -Registers are allocated in order. - - -- Macro: 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 'REG_ALLOC_ORDER' to be an initializer that - lists the highest numbered allocable register first. - - -- Macro: ADJUST_REG_ALLOC_ORDER - 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 '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 - 'reg_alloc_order' before execution of the macro. - - On most machines, it is not necessary to define this macro. - - -- Macro: HONOR_REG_ALLOC_ORDER - Normally, IRA tries to estimate the costs for saving a register in - the prologue and restoring it in the epilogue. This discourages it - from using call-saved registers. If a machine wants to ensure that - IRA allocates registers in the order given by REG_ALLOC_ORDER even - if some call-saved registers appear earlier than call-used ones, - this macro should be defined. - - -- Macro: IRA_HARD_REGNO_ADD_COST_MULTIPLIER (REGNO) - In some case register allocation order is not enough for the - Integrated Register Allocator (IRA) to generate a good code. If - this macro is defined, it should return a floating point value - based on REGNO. The cost of using REGNO for a pseudo will be - increased by approximately the pseudo's usage frequency times the - value returned by this macro. Not defining this macro is - equivalent to having it always return '0.0'. - - On most machines, it is not necessary to define this macro. - - -File: gccint.info, Node: Values in Registers, Next: Leaf Functions, Prev: Allocation Order, Up: Registers - -17.7.3 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. - - -- Macro: HARD_REGNO_NREGS (REGNO, MODE) - A C expression for the number of consecutive hard registers, - starting at register number REGNO, required to hold a value of mode - MODE. This macro must never return zero, even if a register cannot - hold the requested mode - indicate that with HARD_REGNO_MODE_OK - and/or CANNOT_CHANGE_MODE_CLASS instead. - - On a machine where all registers are exactly one word, a suitable - definition of this macro is - - #define HARD_REGNO_NREGS(REGNO, MODE) \ - ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) \ - / UNITS_PER_WORD) - - -- Macro: HARD_REGNO_NREGS_HAS_PADDING (REGNO, MODE) - A C expression that is nonzero if a value of mode MODE, stored in - memory, ends with padding that causes it to take up more space than - in registers starting at register number 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 - '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 - 'subreg_get_info' would otherwise wrongly determine that a 'subreg' - can be represented by an offset to the register number, when in - fact such a 'subreg' would contain some of the padding not stored - in registers and so not be representable. - - -- Macro: HARD_REGNO_NREGS_WITH_PADDING (REGNO, MODE) - For values of REGNO and MODE for which - '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. - - -- Macro: REGMODE_NATURAL_SIZE (MODE) - Define this macro if the natural size of registers that hold values - of mode 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. - - -- Macro: HARD_REGNO_MODE_OK (REGNO, MODE) - A C expression that is nonzero if it is permissible to store a - value of mode MODE in hard register number REGNO (or in several - registers starting with that one). For a machine where all - registers are equivalent, a suitable definition is - - #define HARD_REGNO_MODE_OK(REGNO, MODE) 1 - - You need not include code to check for the numbers of fixed - registers, because the allocation mechanism considers them to be - always occupied. - - 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 'movMODE' 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 'word_mode' will work for - all narrower integer modes, it is not necessary on any machine for - 'HARD_REGNO_MODE_OK' to distinguish between these modes, provided - you define patterns 'movhi', etc., to take advantage of this. This - is useful because of the interaction between 'HARD_REGNO_MODE_OK' - and '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 _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, - '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 - '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 'GENERAL_REGS', - they will not be used unless some pattern's constraint asks for - one. - - -- Macro: HARD_REGNO_RENAME_OK (FROM, TO) - A C expression that is nonzero if it is OK to rename a hard - register FROM to another hard register 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. - - -- Macro: MODES_TIEABLE_P (MODE1, MODE2) - A C expression that is nonzero if a value of mode MODE1 is - accessible in mode MODE2 without copying. - - If 'HARD_REGNO_MODE_OK (R, MODE1)' and 'HARD_REGNO_MODE_OK (R, - MODE2)' are always the same for any R, then 'MODES_TIEABLE_P - (MODE1, MODE2)' should be nonzero. If they differ for any 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. - - -- Target Hook: bool TARGET_HARD_REGNO_SCRATCH_OK (unsigned int REGNO) - This target hook should return 'true' if it is OK to use a hard - register REGNO as scratch reg in peephole2. - - One common use of this macro is to prevent using of a register that - is not saved by a prologue in an interrupt handler. - - The default version of this hook always returns 'true'. - - -- Macro: AVOID_CCMODE_COPIES - Define this macro if the compiler should avoid copies to/from - 'CCmode' registers. You should only define this macro if support - for copying to/from 'CCmode' is incomplete. - - -File: gccint.info, Node: Leaf Functions, Next: Stack Registers, Prev: Values in Registers, Up: Registers - -17.7.4 Handling Leaf Functions ------------------------------- - -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. - - -- Macro: 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. - - -- Macro: LEAF_REG_REMAP (REGNO) - A C expression whose value is the register number to which REGNO - should be renumbered, when a function is treated as a leaf - function. - - If REGNO is a register number which should not appear in a leaf - function before renumbering, then the expression should yield -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. - - 'TARGET_ASM_FUNCTION_PROLOGUE' and 'TARGET_ASM_FUNCTION_EPILOGUE' must -usually treat leaf functions specially. They can test the C variable -'current_function_is_leaf' which is nonzero for leaf functions. -'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 'current_function_uses_only_leaf_regs' which is nonzero for -leaf functions which only use leaf registers. -'current_function_uses_only_leaf_regs' is valid after all passes that -modify the instructions have been run and is only useful if -'LEAF_REGISTERS' is defined. - - -File: gccint.info, Node: Stack Registers, Prev: Leaf Functions, Up: Registers - -17.7.5 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 'reg-stack.c' and -write your machine description to cooperate with it, as well as defining -these macros. - - -- Macro: STACK_REGS - Define this if the machine has any stack-like registers. - - -- Macro: STACK_REG_COVER_CLASS - This is a cover class containing the stack registers. Define this - if the machine has any stack-like registers. - - -- Macro: FIRST_STACK_REG - The number of the first stack-like register. This one is the top - of the stack. - - -- Macro: LAST_STACK_REG - The number of the last stack-like register. This one is the bottom - of the stack. - - -File: gccint.info, Node: Register Classes, Next: Old Constraints, Prev: Registers, Up: Target Macros - -17.8 Register Classes -===================== - -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 "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. - - In general, each register will belong to several classes. In fact, one -class must be named 'ALL_REGS' and contain all the registers. Another -class must be named 'NO_REGS' and contain no registers. Often the union -of two classes will be another class; however, this is not required. - - One of the classes must be named 'GENERAL_REGS'. There is nothing -terribly special about the name, but the operand constraint letters 'r' -and 'g' specify this class. If 'GENERAL_REGS' is the same as -'ALL_REGS', just define it as a macro which expands to 'ALL_REGS'. - - Order the classes so that if class X is contained in class Y then X has -a lower class number than Y. - - The way classes other than '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 must define the narrowest register classes for allocatable -registers, so that each class either has no subclasses, or that for some -mode, the move cost between registers within the class is cheaper than -moving a register in the class to or from memory (*note Costs::). - - 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 'FLOAT_OR_GENERAL_REGS' -which includes both of them. Otherwise you will get suboptimal code, or -even internal compiler errors when reload cannot find a register in the -class computed via 'reg_class_subunion'. - - 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 '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 ('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 'PREFERRED_RELOAD_CLASS' can always have a possible value to -return. - - -- Data type: enum reg_class - An enumerated type that must be defined with all the register class - names as enumerated values. 'NO_REGS' must be first. 'ALL_REGS' - must be the last register class, followed by one more enumerated - value, '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 'int'. The number serves as an index in many of - the tables described below. - - -- Macro: N_REG_CLASSES - The number of distinct register classes, defined as follows: - - #define N_REG_CLASSES (int) LIM_REG_CLASSES - - -- Macro: 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. - - -- Macro: REG_CLASS_CONTENTS - An initializer containing the contents of the register classes, as - integers which are bit masks. The Nth integer specifies the - contents of class N. The way the integer MASK is interpreted is - that register R is in the class if 'MASK & (1 << 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 'HARD_REG_SET' - which is defined in '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. - - -- Macro: REGNO_REG_CLASS (REGNO) - A C expression whose value is a register class containing hard - register REGNO. In general there is more than one such class; - choose a class which is "minimal", meaning that no smaller class - also contains the register. - - -- Macro: 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. - - -- Macro: MODE_BASE_REG_CLASS (MODE) - This is a variation of the 'BASE_REG_CLASS' macro which allows the - selection of a base register in a mode dependent manner. If MODE - is VOIDmode then it should return the same value as - 'BASE_REG_CLASS'. - - -- Macro: MODE_BASE_REG_REG_CLASS (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. - - -- Macro: MODE_CODE_BASE_REG_CLASS (MODE, ADDRESS_SPACE, OUTER_CODE, - INDEX_CODE) - A C expression whose value is the register class to which a valid - base register for a memory reference in mode MODE to address space - ADDRESS_SPACE must belong. OUTER_CODE and INDEX_CODE define the - context in which the base register occurs. OUTER_CODE is the code - of the immediately enclosing expression ('MEM' for the top level of - an address, 'ADDRESS' for something that occurs in an - 'address_operand'). INDEX_CODE is the code of the corresponding - index expression if OUTER_CODE is 'PLUS'; 'SCRATCH' otherwise. - - -- Macro: 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). - - -- Macro: REGNO_OK_FOR_BASE_P (NUM) - A C expression which is nonzero if register number NUM is suitable - for use as a base register in operand addresses. - - -- Macro: REGNO_MODE_OK_FOR_BASE_P (NUM, MODE) - A C expression that is just like 'REGNO_OK_FOR_BASE_P', except that - that expression may examine the mode of the memory reference in - 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 'REGNO_OK_FOR_BASE_P'. The mode may be 'VOIDmode' for - addresses that appear outside a 'MEM', i.e., as an - 'address_operand'. - - -- Macro: REGNO_MODE_OK_FOR_REG_BASE_P (NUM, MODE) - A C expression which is nonzero if register number NUM is suitable - for use as a base register in base plus index operand addresses, - accessing memory in mode 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 - 'REGNO_MODE_CODE_OK_FOR_BASE_P'. - - -- Macro: REGNO_MODE_CODE_OK_FOR_BASE_P (NUM, MODE, ADDRESS_SPACE, - OUTER_CODE, INDEX_CODE) - A C expression which is nonzero if register number NUM is suitable - for use as a base register in operand addresses, accessing memory - in mode MODE in address space ADDRESS_SPACE. This is similar to - 'REGNO_MODE_OK_FOR_BASE_P', except that that expression may examine - the context in which the register appears in the memory reference. - OUTER_CODE is the code of the immediately enclosing expression - ('MEM' if at the top level of the address, 'ADDRESS' for something - that occurs in an 'address_operand'). INDEX_CODE is the code of - the corresponding index expression if OUTER_CODE is 'PLUS'; - 'SCRATCH' otherwise. The mode may be 'VOIDmode' for addresses that - appear outside a 'MEM', i.e., as an 'address_operand'. - - -- Macro: REGNO_OK_FOR_INDEX_P (NUM) - A C expression which is nonzero if register number 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. - - -- Target Hook: reg_class_t TARGET_PREFERRED_RENAME_CLASS (reg_class_t - RCLASS) - A target hook that places additional preference on the register - class to use when it is necessary to rename a register in class - RCLASS to another class, or perhaps NO_REGS, if no preferred - register class is found or hook 'preferred_rename_class' is not - implemented. Sometimes returning a more restrictive class makes - better code. For example, on ARM, thumb-2 instructions using - 'LO_REGS' may be smaller than instructions using 'GENERIC_REGS'. - By returning 'LO_REGS' from 'preferred_rename_class', code size can - be reduced. - - -- Target Hook: reg_class_t TARGET_PREFERRED_RELOAD_CLASS (rtx X, - reg_class_t RCLASS) - A target hook that places additional restrictions on the register - class to use when it is necessary to copy value X into a register - in class RCLASS. The value is a register class; perhaps RCLASS, or - perhaps another, smaller class. - - The default version of this hook always returns value of 'rclass' - argument. - - Sometimes returning a more restrictive class makes better code. - For example, on the 68000, when X is an integer constant that is in - range for a 'moveq' instruction, the value of this macro is always - 'DATA_REGS' as long as RCLASS includes the data registers. - Requiring a data register guarantees that a 'moveq' will be used. - - One case where 'TARGET_PREFERRED_RELOAD_CLASS' must not return - RCLASS is if X is a legitimate constant which cannot be loaded into - some register class. By returning 'NO_REGS' you can force 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 - 'TARGET_PREFERRED_RELOAD_CLASS' returns 'NO_REGS' when X is a - floating-point constant. If the constant can't be loaded into any - kind of register, code generation will be better if - 'TARGET_LEGITIMATE_CONSTANT_P' makes the constant illegitimate - instead of using 'TARGET_PREFERRED_RELOAD_CLASS'. - - If an insn has pseudos in it after register allocation, reload will - go through the alternatives and call repeatedly - 'TARGET_PREFERRED_RELOAD_CLASS' to find the best one. Returning - 'NO_REGS', in this case, makes reload add a '!' 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). - - -- Macro: PREFERRED_RELOAD_CLASS (X, CLASS) - A C expression that places additional restrictions on the register - class to use when it is necessary to copy value X into a register - in class CLASS. The value is a register class; perhaps CLASS, or - perhaps another, smaller class. On many machines, the following - definition is safe: - - #define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS - - Sometimes returning a more restrictive class makes better code. - For example, on the 68000, when X is an integer constant that is in - range for a 'moveq' instruction, the value of this macro is always - 'DATA_REGS' as long as CLASS includes the data registers. - Requiring a data register guarantees that a 'moveq' will be used. - - One case where 'PREFERRED_RELOAD_CLASS' must not return CLASS is if - X is a legitimate constant which cannot be loaded into some - register class. By returning 'NO_REGS' you can force 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 - 'PREFERRED_RELOAD_CLASS' returns 'NO_REGS' when X is a - floating-point constant. If the constant can't be loaded into any - kind of register, code generation will be better if - 'TARGET_LEGITIMATE_CONSTANT_P' makes the constant illegitimate - instead of using 'TARGET_PREFERRED_RELOAD_CLASS'. - - If an insn has pseudos in it after register allocation, reload will - go through the alternatives and call repeatedly - 'PREFERRED_RELOAD_CLASS' to find the best one. Returning - 'NO_REGS', in this case, makes reload add a '!' 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). - - -- Target Hook: reg_class_t TARGET_PREFERRED_OUTPUT_RELOAD_CLASS (rtx - X, reg_class_t RCLASS) - Like 'TARGET_PREFERRED_RELOAD_CLASS', but for output reloads - instead of input reloads. - - The default version of this hook always returns value of 'rclass' - argument. - - You can also use 'TARGET_PREFERRED_OUTPUT_RELOAD_CLASS' to - discourage reload from using some alternatives, like - 'TARGET_PREFERRED_RELOAD_CLASS'. - - -- Macro: LIMIT_RELOAD_CLASS (MODE, 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 MODE in a reload register for which class CLASS would - ordinarily be used. - - Unlike '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 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. - - -- Target Hook: reg_class_t TARGET_SECONDARY_RELOAD (bool IN_P, rtx X, - reg_class_t RELOAD_CLASS, enum machine_mode RELOAD_MODE, - secondary_reload_info *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 '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 than 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 IN_P, - and X is an rtx that needs to be copied to a register of class - RELOAD_CLASS in RELOAD_MODE. For output reloads, this target hook - is called with zero IN_P, and a register of class RELOAD_CLASS - needs to be copied to rtx X in RELOAD_MODE. - - If copying a register of RELOAD_CLASS from/to X requires an - intermediate register, the hook '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 X. - - You do this by setting '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 output constraint. - - When an intermediate register is used, the 'secondary_reload' hook - will be called again to determine how to copy the intermediate - register to/from the reload operand X, so your hook must also have - code to handle the register class of the intermediate operand. - - X might be a pseudo-register or a 'subreg' of a pseudo-register, - which could either be in a hard register or in memory. Use - 'true_regnum' to find out; it will return -1 if the pseudo is in - memory and the hard register number if it is in a register. - - Scratch operands in memory (constraint '"=m"' / '"=&m"') are - currently not supported. For the time being, you will have to - continue to use 'SECONDARY_MEMORY_NEEDED' for that purpose. - - '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 '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 - 'sri->extra_cost' to a negative amount. - - -- Macro: SECONDARY_RELOAD_CLASS (CLASS, MODE, X) - -- Macro: SECONDARY_INPUT_RELOAD_CLASS (CLASS, MODE, X) - -- Macro: SECONDARY_OUTPUT_RELOAD_CLASS (CLASS, MODE, X) - These macros are obsolete, new ports should use the target hook - 'TARGET_SECONDARY_RELOAD' instead. - - These are obsolete macros, replaced by the - '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 X to a - register CLASS in MODE requires an intermediate register, you were - supposed to define '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 CLASS in MODE to X requires an intermediate - or scratch register, '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 'SECONDARY_RELOAD_CLASS' should have been used - instead of defining both macros identically. - - The values returned by these macros are often 'GENERAL_REGS'. - Return 'NO_REGS' if no spare register is needed; i.e., if X can be - directly copied to or from a register of CLASS in MODE without - requiring a scratch register. Do not define this macro if it would - always return 'NO_REGS'. - - If a scratch register is required (either with or without an - intermediate register), you were supposed to define patterns for - 'reload_inM' or 'reload_outM', as required (*note Standard Names::. - These patterns, which were normally implemented with a - 'define_expand', should be similar to the 'movM' 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 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. - - X might be a pseudo-register or a 'subreg' of a pseudo-register, - which could either be in a hard register or in memory. Use - 'true_regnum' to find out; it will return -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 'movM' pattern should use - memory as an intermediate storage. This case often occurs between - floating-point and general registers. - - -- Macro: SECONDARY_MEMORY_NEEDED (CLASS1, CLASS2, 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 M in registers of CLASS1 can only be copied to - registers of class CLASS2 by storing a register of CLASS1 into - memory and loading that memory location into a register of CLASS2. - - Do not define this macro if its value would always be zero. - - -- Macro: SECONDARY_MEMORY_NEEDED_RTX (MODE) - Normally when '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 - 'SECONDARY_MEMORY_NEEDED'. - - -- Macro: SECONDARY_MEMORY_NEEDED_MODE (MODE) - When the compiler needs a secondary memory location to copy between - two registers of mode MODE, it normally allocates sufficient memory - to hold a quantity of '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 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 'alpha.h' for details. - - Do not define this macro if you do not define - 'SECONDARY_MEMORY_NEEDED' or if widening MODE to a mode that is - 'BITS_PER_WORD' bits wide is correct for your machine. - - -- Target Hook: bool TARGET_CLASS_LIKELY_SPILLED_P (reg_class_t RCLASS) - A target hook which returns 'true' if pseudos that have been - assigned to registers of class RCLASS would likely be spilled - because registers of RCLASS are needed for spill registers. - - The default version of this target hook returns 'true' if RCLASS - has exactly one register and 'false' otherwise. On most machines, - this default should be used. For generally register-starved - machines, such as i386, or machines with right register - constraints, such as SH, this hook can be used to avoid excessive - spilling. - - This hook is also used by some of the global intra-procedural code - transformations to throtle code motion, to avoid increasing - register pressure. - - -- Target Hook: unsigned char TARGET_CLASS_MAX_NREGS (reg_class_t - RCLASS, enum machine_mode MODE) - A target hook returns the maximum number of consecutive registers - of class RCLASS needed to hold a value of mode MODE. - - This is closely related to the macro 'HARD_REGNO_NREGS'. In fact, - the value returned by 'TARGET_CLASS_MAX_NREGS (RCLASS, MODE)' - target hook should be the maximum value of 'HARD_REGNO_NREGS - (REGNO, MODE)' for all REGNO values in the class RCLASS. - - This target hook helps control the handling of multiple-word values - in the reload pass. - - The default version of this target hook returns the size of MODE in - words. - - -- Macro: CLASS_MAX_NREGS (CLASS, MODE) - A C expression for the maximum number of consecutive registers of - class CLASS needed to hold a value of mode MODE. - - This is closely related to the macro 'HARD_REGNO_NREGS'. In fact, - the value of the macro 'CLASS_MAX_NREGS (CLASS, MODE)' should be - the maximum value of 'HARD_REGNO_NREGS (REGNO, MODE)' for all REGNO - values in the class CLASS. - - This macro helps control the handling of multiple-word values in - the reload pass. - - -- Macro: CANNOT_CHANGE_MODE_CLASS (FROM, TO, CLASS) - If defined, a C expression that returns nonzero for a CLASS for - which a change from mode FROM to mode 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, 'alpha.h' defines - 'CANNOT_CHANGE_MODE_CLASS' as below: - - #define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \ - (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \ - ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0) - - -- Target Hook: bool TARGET_LRA_P (void) - A target hook which returns true if we use LRA instead of reload - pass. It means that LRA was ported to the target. The default - version of this target hook returns always false. - - -- Target Hook: int TARGET_REGISTER_PRIORITY (int) - A target hook which returns the register priority number to which - the register HARD_REGNO belongs to. The bigger the number, the - more preferable the hard register usage (when all other conditions - are the same). This hook can be used to prefer some hard register - over others in LRA. For example, some x86-64 register usage needs - additional prefix which makes instructions longer. The hook can - return lower priority number for such registers make them less - favorable and as result making the generated code smaller. The - default version of this target hook returns always zero. - - -- Target Hook: bool TARGET_REGISTER_USAGE_LEVELING_P (void) - A target hook which returns true if we need register usage - leveling. That means if a few hard registers are equally good for - the assignment, we choose the least used hard register. The - register usage leveling may be profitable for some targets. Don't - use the usage leveling for targets with conditional execution or - targets with big register files as it hurts if-conversion and - cross-jumping optimizations. The default version of this target - hook returns always false. - - -- Target Hook: bool TARGET_DIFFERENT_ADDR_DISPLACEMENT_P (void) - A target hook which returns true if an address with the same - structure can have different maximal legitimate displacement. For - example, the displacement can depend on memory mode or on operand - combinations in the insn. The default version of this target hook - returns always false. - - -- Target Hook: reg_class_t TARGET_SPILL_CLASS (reg_class_t, enum - MACHINE_MODE) - This hook defines a class of registers which could be used for - spilling pseudos of the given mode and class, or 'NO_REGS' if only - memory should be used. Not defining this hook is equivalent to - returning 'NO_REGS' for all inputs. - - -- Target Hook: enum machine_mode TARGET_CSTORE_MODE (enum insn_code - ICODE) - This hook defines the machine mode to use for the boolean result of - conditional store patterns. The ICODE argument is the instruction - code for the cstore being performed. Not definiting this hook is - the same as accepting the mode encoded into operand 0 of the cstore - expander patterns. - - -File: gccint.info, Node: Old Constraints, Next: Stack and Calling, Prev: Register Classes, Up: Target Macros - -17.9 Obsolete Macros for Defining Constraints -============================================= - -Machine-specific constraints can be defined with these macros instead of -the machine description constructs described in *note Define -Constraints::. This mechanism is obsolete. New ports should not use -it; old ports should convert to the new mechanism. - - -- Macro: CONSTRAINT_LEN (CHAR, STR) - For the constraint at the start of STR, which starts with the - letter 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. - - -- Macro: REG_CLASS_FROM_LETTER (CHAR) - A C expression which defines the machine-dependent operand - constraint letters for register classes. If CHAR is such a letter, - the value should be the register class corresponding to it. - Otherwise, the value should be 'NO_REGS'. The register letter 'r', - corresponding to class 'GENERAL_REGS', will not be passed to this - macro; you do not need to handle it. - - -- Macro: REG_CLASS_FROM_CONSTRAINT (CHAR, STR) - Like 'REG_CLASS_FROM_LETTER', but you also get the constraint - string passed in STR, so that you can use suffixes to distinguish - between different variants. - - -- Macro: CONST_OK_FOR_LETTER_P (VALUE, C) - A C expression that defines the machine-dependent operand - constraint letters ('I', 'J', 'K', ... 'P') that specify particular - ranges of integer values. If C is one of those letters, the - expression should check that VALUE, an integer, is in the - appropriate range and return 1 if so, 0 otherwise. If C is not one - of those letters, the value should be 0 regardless of VALUE. - - -- Macro: CONST_OK_FOR_CONSTRAINT_P (VALUE, C, STR) - Like 'CONST_OK_FOR_LETTER_P', but you also get the constraint - string passed in STR, so that you can use suffixes to distinguish - between different variants. - - -- Macro: CONST_DOUBLE_OK_FOR_LETTER_P (VALUE, C) - A C expression that defines the machine-dependent operand - constraint letters that specify particular ranges of 'const_double' - values ('G' or 'H'). - - If C is one of those letters, the expression should check that - VALUE, an RTX of code 'const_double', is in the appropriate range - and return 1 if so, 0 otherwise. If C is not one of those letters, - the value should be 0 regardless of VALUE. - - 'const_double' is used for all floating-point constants and for - 'DImode' fixed-point constants. A given letter can accept either - or both kinds of values. It can use 'GET_MODE' to distinguish - between these kinds. - - -- Macro: CONST_DOUBLE_OK_FOR_CONSTRAINT_P (VALUE, C, STR) - Like 'CONST_DOUBLE_OK_FOR_LETTER_P', but you also get the - constraint string passed in STR, so that you can use suffixes to - distinguish between different variants. - - -- Macro: EXTRA_CONSTRAINT (VALUE, 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 - 'REG_CLASS_FROM_LETTER' / '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 VALUE corresponds to the operand type represented by the - constraint letter C. If C is not defined as an extra constraint, - the value returned should be 0 regardless of VALUE. - - For example, on the ROMP, load instructions cannot have their - output in r0 if the memory reference contains a symbolic address. - Constraint letter 'Q' is defined as representing a memory address - that does _not_ contain a symbolic address. An alternative is - specified with a 'Q' constraint on the input and 'r' on the output. - The next alternative specifies 'm' on the input and a register - class that does not include r0 on the output. - - -- Macro: EXTRA_CONSTRAINT_STR (VALUE, C, STR) - Like 'EXTRA_CONSTRAINT', but you also get the constraint string - passed in STR, so that you can use suffixes to distinguish between - different variants. - - -- Macro: EXTRA_MEMORY_CONSTRAINT (C, STR) - A C expression that defines the optional machine-dependent - constraint letters, amongst those accepted by '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 STR, the first letter of which is the - letter 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 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 'Q' is defined via - 'EXTRA_CONSTRAINT' as representing a memory address of this type. - If the letter 'Q' is marked as 'EXTRA_MEMORY_CONSTRAINT', a '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 an 'o' - constraint can handle any memory operand. - - -- Macro: EXTRA_ADDRESS_CONSTRAINT (C, STR) - A C expression that defines the optional machine-dependent - constraint letters, amongst those accepted by 'EXTRA_CONSTRAINT' / - '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 STR, which starts with the letter 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 STR, by copying it into a base register. - - Any constraint marked as 'EXTRA_ADDRESS_CONSTRAINT' can only be - used with the 'address_operand' predicate. It is treated - analogously to the 'p' constraint. - - -File: gccint.info, Node: Stack and Calling, Next: Varargs, Prev: Old Constraints, Up: Target Macros - -17.10 Stack Layout and Calling Conventions -========================================== - -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:: - - -File: gccint.info, Node: Frame Layout, Next: Exception Handling, Up: Stack and Calling - -17.10.1 Basic Stack Layout --------------------------- - -Here is the basic stack layout. - - -- Macro: 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 ...", it means that the compiler - checks this macro only with '#ifdef' so the precise definition used - does not matter. - - -- Macro: STACK_PUSH_CODE - This macro defines the operation used when something is pushed on - the stack. In RTL, a push operation will be '(set (mem - (STACK_PUSH_CODE (reg sp))) ...)' - - The choices are 'PRE_DEC', 'POST_DEC', 'PRE_INC', and '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 'PRE_DEC' when 'STACK_GROWS_DOWNWARD' is defined, - which is almost always right, and 'PRE_INC' otherwise, which is - often wrong. - - -- Macro: FRAME_GROWS_DOWNWARD - Define this macro to nonzero value if the addresses of local - variable slots are at negative offsets from the frame pointer. - - -- Macro: ARGS_GROW_DOWNWARD - Define this macro if successive arguments to a function occupy - decreasing addresses on the stack. - - -- Macro: STARTING_FRAME_OFFSET - Offset from the frame pointer to the first local variable slot to - be allocated. - - If 'FRAME_GROWS_DOWNWARD', find the next slot's offset by - subtracting the first slot's length from 'STARTING_FRAME_OFFSET'. - Otherwise, it is found by adding the length of the first slot to - the value 'STARTING_FRAME_OFFSET'. - - -- Macro: 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 'STARTING_FRAME_OFFSET' is nonzero or where there is - a register save block following the local block that doesn't - require alignment to 'STACK_BOUNDARY', it may be beneficial to - disable stack alignment and do it in the backend. - - -- Macro: 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 'ARGS_GROW_DOWNWARD', this is the offset to the location above - the first location at which outgoing arguments are placed. - - -- Macro: FIRST_PARM_OFFSET (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 'ARGS_GROW_DOWNWARD', this is the offset to the location above - the first argument's address. - - -- Macro: STACK_DYNAMIC_OFFSET (FUNDECL) - Offset from the stack pointer register to an item dynamically - allocated on the stack, e.g., by 'alloca'. - - The default value for this macro is 'STACK_POINTER_OFFSET' plus the - length of the outgoing arguments. The default is correct for most - machines. See 'function.c' for details. - - -- Macro: INITIAL_FRAME_ADDRESS_RTX - A C expression whose value is RTL representing the address of the - initial stack frame. This address is passed to 'RETURN_ADDR_RTX' - and '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 - '__builtin_frame_address (count)' and '__builtin_return_address - (count)' for 'count' not equal to zero. - - -- Macro: DYNAMIC_CHAIN_ADDRESS (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 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 FRAMEADDR--that is, the stack frame address is also the address - of the stack word that points to the previous frame. - - -- Macro: 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. - - -- Target Hook: rtx TARGET_BUILTIN_SETJMP_FRAME_VALUE (void) - This target hook should return an rtx that is used to store the - address of the current frame into the built in 'setjmp' buffer. - The default value, 'virtual_stack_vars_rtx', is correct for most - machines. One reason you may need to define this target hook is if - 'hard_frame_pointer_rtx' is the appropriate value on your machine. - - -- Macro: FRAME_ADDR_RTX (FRAMEADDR) - A C expression whose value is RTL representing the value of the - frame address for the current frame. 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. - - -- Macro: RETURN_ADDR_RTX (COUNT, FRAMEADDR) - A C expression whose value is RTL representing the value of the - return address for the frame COUNT steps up from the current frame, - after the prologue. FRAMEADDR is the frame pointer of the COUNT - frame, or the frame pointer of the COUNT - 1 frame if - 'RETURN_ADDR_IN_PREVIOUS_FRAME' is defined. - - The value of the expression must always be the correct address when - COUNT is zero, but may be 'NULL_RTX' if there is no way to - determine the return address of other frames. - - -- Macro: 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. - - -- Macro: 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 'REG', indicating that the - return value is saved in 'REG', or a '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 'REG', you should also define - 'DWARF_FRAME_RETURN_COLUMN' to 'DWARF_FRAME_REGNUM (REGNO)'. - - -- Macro: 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 alternative return column. The - column must not correspond to any gcc hard register (that is, it - must not be in the range of 'DWARF_FRAME_REGNUM'). - - This macro can be useful if 'DWARF_FRAME_RETURN_COLUMN' is set to a - general register, but an alternative column needs to be used for - signal frames. Some targets have also used different frame return - columns over time. - - -- Macro: 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. - - -- Target Hook: void TARGET_DWARF_HANDLE_FRAME_UNSPEC (const char - *LABEL, rtx PATTERN, int 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 - (set (reg) (unspec [...] UNSPEC_INDEX)) - and - (set (reg) (unspec_volatile [...] UNSPECV_INDEX)). - to let the backend emit the call frame instructions. LABEL is the - CFI label attached to the insn, PATTERN is the pattern of the insn - and INDEX is 'UNSPEC_INDEX' or 'UNSPECV_INDEX'. - - -- Macro: 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. - - -- Macro: ARG_POINTER_CFA_OFFSET (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 - 'INCOMING_FRAME_SP_OFFSET'. Which is unfortunately not usable - during virtual register instantiation. - - The default value for this macro is 'FIRST_PARM_OFFSET (fundecl) + - crtl->args.pretend_args_size', 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. - - -- Macro: FRAME_POINTER_CFA_OFFSET (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 'INCOMING_FRAME_SP_OFFSET'. - - Normally the CFA is calculated as an offset from the argument - pointer, via '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 'FRAME_POINTER_CFA_OFFSET' and - 'ARG_POINTER_CFA_OFFSET' should be defined. - - -- Macro: CFA_FRAME_BASE_OFFSET (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. - - -File: gccint.info, Node: Exception Handling, Next: Stack Checking, Prev: Frame Layout, Up: Stack and Calling - -17.10.2 Exception Handling Support ----------------------------------- - - -- Macro: EH_RETURN_DATA_REGNO (N) - A C expression whose value is the Nth register number used for data - by exception handlers, or 'INVALID_REGNUM' if fewer than 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. - - -- Macro: 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. - - -- Macro: 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 _target_ call frame rather than inside the current - call frame. If defined, '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 '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 'eh_return' instruction pattern. - - -- Macro: 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. - - -- Macro: ASM_PREFERRED_EH_DATA_FORMAT (CODE, 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. - - CODE is 0 for data, 1 for code labels, 2 for function pointers. - GLOBAL is true if the symbol may be affected by dynamic - relocations. The macro should return a combination of the - 'DW_EH_PE_*' defines as found in 'dwarf2.h'. - - If this macro is not defined, pointers will not be encoded but - represented directly. - - -- Macro: ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (FILE, ENCODING, SIZE, - ADDR, DONE) - This macro allows the target to emit whatever special magic is - required to represent the encoding chosen by - '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 DONE if the format was - handled. ENCODING is the format chosen, SIZE is the number of - bytes that the format occupies, ADDR is the 'SYMBOL_REF' to be - emitted. - - -- Macro: MD_FALLBACK_FRAME_STATE_FOR (CONTEXT, 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 'uw_frame_state_for' in 'unwind-dw2.c', - 'unwind-dw2-xtensa.c' and 'unwind-ia64.c'. CONTEXT is an - '_Unwind_Context'; FS is an '_Unwind_FrameState'. Examine - 'context->ra' for the address of the code being executed and - 'context->cfa' for the stack pointer value. If the frame can be - decoded, the register save addresses should be updated in FS and - the macro should evaluate to '_URC_NO_REASON'. If the frame cannot - be decoded, the macro should evaluate to '_URC_END_OF_STACK'. - - For proper signal handling in Java this macro is accompanied by - 'MAKE_THROW_FRAME', defined in 'libjava/include/*-signal.h' - headers. - - -- Macro: MD_HANDLE_UNWABI (CONTEXT, FS) - This macro allows the target to add operating system specific code - to the call-frame unwinder to handle the IA-64 '.unwabi' unwinding - directive, usually used for signal or interrupt frames. - - This macro is called from 'uw_update_context' in libgcc's - 'unwind-ia64.c'. CONTEXT is an '_Unwind_Context'; FS is an - '_Unwind_FrameState'. Examine 'fs->unwabi' for the abi and context - in the '.unwabi' directive. If the '.unwabi' directive can be - handled, the register save addresses should be updated in FS. - - -- Macro: 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 '1' if comdat - linkage is necessary. The default is '0'. - - -File: gccint.info, Node: Stack Checking, Next: Frame Registers, Prev: Exception Handling, Up: Stack and Calling - -17.10.3 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: - - 1. If the value of the 'STACK_CHECK_BUILTIN' macro is nonzero, GCC - will assume that you have arranged for full stack checking to be - done at appropriate places in the configuration files. GCC will - not do other special processing. - - 2. If 'STACK_CHECK_BUILTIN' is zero and the value of the - 'STACK_CHECK_STATIC_BUILTIN' macro is nonzero, GCC will assume that - you have arranged for static stack checking (checking of the static - stack frame of functions) to be done at appropriate places in the - configuration files. GCC will only emit code to do dynamic stack - checking (checking on dynamic stack allocations) using the third - approach below. - - 3. 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. - - If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is -defined, GCC will change its allocation strategy for large objects if -the option '-fstack-check' is specified: they will always be allocated -dynamically if their size exceeds 'STACK_CHECK_MAX_VAR_SIZE' bytes. - - -- Macro: 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 required by the ABI of your machine or if you - would like to do stack checking in some more efficient way than the - generic approach. The default value of this macro is zero. - - -- Macro: STACK_CHECK_STATIC_BUILTIN - A nonzero value if static stack checking is done by the - configuration files in a machine-dependent manner. You should - define this macro if you would like to do static stack checking in - some more efficient way than the generic approach. The default - value of this macro is zero. - - -- Macro: STACK_CHECK_PROBE_INTERVAL_EXP - An integer specifying the interval at which GCC must generate stack - probe instructions, defined as 2 raised to this integer. You will - normally define this macro so that the interval be no larger than - the size of the "guard pages" at the end of a stack area. The - default value of 12 (4096-byte interval) is suitable for most - systems. - - -- Macro: STACK_CHECK_MOVING_SP - An integer which is nonzero if GCC should move the stack pointer - page by page when doing probes. This can be necessary on systems - where the stack pointer contains the bottom address of the memory - area accessible to the executing thread at any point in time. In - this situation an alternate signal stack is required in order to be - able to recover from a stack overflow. The default value of this - macro is zero. - - -- Macro: 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 with the 'setjmp'/'longjmp'-based - exception handling mechanism and 8192 bytes with other exception - handling mechanisms should be adequate for most machines. - - The following macros are relevant only if neither STACK_CHECK_BUILTIN -nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether -in the opposite case. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: 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 - '-fstack-check'. GCC computed the default from the values of the - above macros and you will normally not need to override that - default. - - -File: gccint.info, Node: Frame Registers, Next: Elimination, Prev: Stack Checking, Up: Stack and Calling - -17.10.4 Registers That Address the Stack Frame ----------------------------------------------- - -This discusses registers that address the stack frame. - - -- Macro: STACK_POINTER_REGNUM - The register number of the stack pointer register, which must also - be a fixed register according to 'FIXED_REGISTERS'. On most - machines, the hardware determines which register this is. - - -- Macro: 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. - - -- Macro: 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 - 'FRAME_POINTER_REGNUM' the number of a special, fixed register to - be used internally until the offset is known, and define - '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 'ELIMINABLE_REGS' how to eliminate - 'FRAME_POINTER_REGNUM' into either 'HARD_FRAME_POINTER_REGNUM' or - 'STACK_POINTER_REGNUM'. - - Do not define this macro if it would be the same as - 'FRAME_POINTER_REGNUM'. - - -- Macro: 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 'FIXED_REGISTERS', or arrange to - be able to eliminate it (*note Elimination::). - - -- Macro: HARD_FRAME_POINTER_IS_FRAME_POINTER - Define this to a preprocessor constant that is nonzero if - 'hard_frame_pointer_rtx' and 'frame_pointer_rtx' should be the - same. The default definition is '(HARD_FRAME_POINTER_REGNUM == - FRAME_POINTER_REGNUM)'; you only need to define this macro if that - definition is not suitable for use in preprocessor conditionals. - - -- Macro: HARD_FRAME_POINTER_IS_ARG_POINTER - Define this to a preprocessor constant that is nonzero if - 'hard_frame_pointer_rtx' and 'arg_pointer_rtx' should be the same. - The default definition is '(HARD_FRAME_POINTER_REGNUM == - ARG_POINTER_REGNUM)'; you only need to define this macro if that - definition is not suitable for use in preprocessor conditionals. - - -- Macro: 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 '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. - - -- Macro: STATIC_CHAIN_REGNUM - -- Macro: 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 'STATIC_CHAIN_INCOMING_REGNUM', while the - register number as seen by the calling function is - 'STATIC_CHAIN_REGNUM'. If these registers are the same, - '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 'TARGET_STATIC_CHAIN' hook should be used. - - -- Target Hook: rtx TARGET_STATIC_CHAIN (const_tree FNDECL, bool - INCOMING_P) - This hook replaces the use of 'STATIC_CHAIN_REGNUM' et al for - targets that may use different static chain locations for different - nested functions. This may be required if the target has function - attributes that affect the calling conventions of the function and - those calling conventions use different static chain locations. - - The default version of this hook uses 'STATIC_CHAIN_REGNUM' et al. - - If the static chain is passed in memory, this hook should be used - to provide rtx giving 'mem' expressions that denote where they are - stored. Often the 'mem' expression as seen by the caller will be - at an offset from the stack pointer and the 'mem' expression as - seen by the callee will be at an offset from the frame pointer. - The variables 'stack_pointer_rtx', 'frame_pointer_rtx', and - 'arg_pointer_rtx' will have been initialized and should be used to - refer to those items. - - -- Macro: 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 - 'FIRST_PSEUDO_REGISTER'. - - -- Macro: PRE_GCC3_DWARF_FRAME_REGISTERS - - This macro is similar to '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 - 'DWARF_FRAME_REGISTERS'. - - -- Macro: DWARF_REG_TO_UNWIND_COLUMN (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. - - -- Macro: DWARF_FRAME_REGNUM (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 'DBX_REGISTER_NUMBER (REGNO)'. - - -- Macro: DWARF2_FRAME_REG_OUT (REGNO, FOR_EH) - - Define this macro to map register numbers held in the call frame - info that GCC has collected using 'DWARF_FRAME_REGNUM' to those - that should be output in .debug_frame ('FOR_EH' is zero) and - .eh_frame ('FOR_EH' is nonzero). The default is to return 'REGNO'. - - -- Macro: REG_VALUE_IN_UNWIND_CONTEXT - - Define this macro if the target stores register values as - '_Unwind_Word' type in unwind context. It should be defined if - target register size is larger than the size of 'void *'. The - default is to store register values as 'void *' type. - - -- Macro: ASSUME_EXTENDED_UNWIND_CONTEXT - - Define this macro to be 1 if the target always uses extended unwind - context with version, args_size and by_value fields. If it is - undefined, it will be defined to 1 when - 'REG_VALUE_IN_UNWIND_CONTEXT' is defined and 0 otherwise. - - -File: gccint.info, Node: Elimination, Next: Stack Arguments, Prev: Frame Registers, Up: Stack and Calling - -17.10.5 Eliminating Frame Pointer and Arg Pointer -------------------------------------------------- - -This is about eliminating the frame pointer and arg pointer. - - -- Target Hook: bool TARGET_FRAME_POINTER_REQUIRED (void) - This target hook should return 'true' if a function must have and - use a frame pointer. This target hook is called in the reload - pass. If its return value is 'true' the function will have a frame - pointer. - - This target hook can in principle examine the current function and - decide according to the facts, but on most machines the constant - 'false' or the constant 'true' suffices. Use 'false' when the - machine allows code to be generated with no frame pointer, and - doing so saves some time or space. Use 'true' 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 'TARGET_FRAME_POINTER_REQUIRED' returns. 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 'FIXED_REGISTERS' for more - information. - - Default return value is 'false'. - - -- Macro: INITIAL_FRAME_POINTER_OFFSET (DEPTH-VAR) - A C statement to store in the variable 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 'get_frame_size ()' and the - tables of registers 'regs_ever_live' and 'call_used_regs'. - - If 'ELIMINABLE_REGS' is defined, this macro will be not be used and - need not be defined. Otherwise, it must be defined even if - 'TARGET_FRAME_POINTER_REQUIRED' always returns true; in that case, - you may set DEPTH-VAR to anything. - - -- Macro: 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: - #define ELIMINABLE_REGS \ - {{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM}, \ - {ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM}, \ - {FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}} - - Note that the elimination of the argument pointer with the stack - pointer is specified first since that is the preferred elimination. - - -- Target Hook: bool TARGET_CAN_ELIMINATE (const int FROM_REG, const - int TO_REG) - This target hook should returns 'true' if the compiler is allowed - to try to replace register number FROM_REG with register number - TO_REG. This target hook need only be defined if 'ELIMINABLE_REGS' - is defined, and will usually be 'true', since most of the cases - preventing register elimination are things that the compiler - already knows about. - - Default return value is 'true'. - - -- Macro: INITIAL_ELIMINATION_OFFSET (FROM-REG, TO-REG, OFFSET-VAR) - This macro is similar to 'INITIAL_FRAME_POINTER_OFFSET'. It - specifies the initial difference between the specified pair of - registers. This macro must be defined if 'ELIMINABLE_REGS' is - defined. - - -File: gccint.info, Node: Stack Arguments, Next: Register Arguments, Prev: Elimination, Up: Stack and Calling - -17.10.6 Passing Function Arguments on the Stack ------------------------------------------------ - -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. - - -- Target Hook: bool TARGET_PROMOTE_PROTOTYPES (const_tree FNTYPE) - This target hook returns 'true' if an argument declared in a - prototype as an integral type smaller than 'int' should actually be - passed as an '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. - - -- Macro: 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 'PUSH_ARGS' is nonzero, 'PUSH_ROUNDING' - must be defined too. - - -- Macro: 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 'PUSH_ARGS' on targets where the - stack and args grow in opposite directions, and 0 otherwise. - - -- Macro: PUSH_ROUNDING (NPUSHED) - A C expression that is the number of bytes actually pushed onto the - stack when an instruction attempts to push NPUSHED bytes. - - On some machines, the definition - - #define PUSH_ROUNDING(BYTES) (BYTES) - - 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 - - #define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1) - - If the value of this macro has a type, it should be an unsigned - type. - - -- Macro: ACCUMULATE_OUTGOING_ARGS - A C expression. If nonzero, the maximum amount of space required - for outgoing arguments will be computed and placed into - 'crtl->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 'PUSH_ARGS' and 'ACCUMULATE_OUTGOING_ARGS' is not - proper. - - -- Macro: REG_PARM_STACK_SPACE (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 - FNDECL, which can be zero if GCC is calling a library function. - The argument FNDECL can be the FUNCTION_DECL, or the type itself of - the function. - - This space can be allocated by the caller, or be a part of the - machine-dependent stack frame: 'OUTGOING_REG_PARM_STACK_SPACE' says - which. - - -- Macro: OUTGOING_REG_PARM_STACK_SPACE (FNTYPE) - Define this to a nonzero value if it is the responsibility of the - caller to allocate the area reserved for arguments passed in - registers when calling a function of FNTYPE. FNTYPE may be NULL if - the function called is a library function. - - If 'ACCUMULATE_OUTGOING_ARGS' is defined, this macro controls - whether the space for these arguments counts in the value of - 'crtl->outgoing_args_size'. - - -- Macro: STACK_PARMS_IN_REG_PARM_AREA - Define this macro if 'REG_PARM_STACK_SPACE' is defined, but the - stack parameters don't skip the area specified by it. - - Normally, when a parameter is not passed in registers, it is placed - on the stack beyond the '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. - - -- Target Hook: int TARGET_RETURN_POPS_ARGS (tree FUNDECL, tree - FUNTYPE, int SIZE) - This target hook returns 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. - - FUNDECL is a C variable whose value is a tree node that describes - the function in question. Normally it is a node of type - 'FUNCTION_DECL' that describes the declaration of the function. - From this you can obtain the 'DECL_ATTRIBUTES' of the function. - - FUNTYPE is a C variable whose value is a tree node that describes - the function in question. Normally it is a node of type - '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, 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. - - 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 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 'printf') pop - nothing (the caller pops all). When this convention is in use, - FUNTYPE is examined to determine whether a function takes a fixed - number of arguments. - - -- Macro: CALL_POPS_ARGS (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 - 'RETURN_POPS_ARGS' when compiling a function call. - - 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, - 'RETURN_POPS_ARGS' is not appropriate. - - -File: gccint.info, Node: Register Arguments, Next: Scalar Return, Prev: Stack Arguments, Up: Stack and Calling - -17.10.7 Passing Arguments in Registers --------------------------------------- - -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. - - -- Target Hook: rtx TARGET_FUNCTION_ARG (cumulative_args_t CA, enum - machine_mode MODE, const_tree TYPE, bool NAMED) - Return an RTX indicating whether a function argument is passed in a - register and if so, which register. - - The arguments are CA, which summarizes all the previous arguments; - MODE, the machine mode of the argument; 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 NAMED, which is 'true' for an - ordinary argument and 'false' for nameless arguments that - correspond to '...' in the called function's prototype. TYPE can - be an incomplete type if a syntax error has previously occurred. - - The return value is usually either a 'reg' RTX for the hard - register in which to pass the argument, or zero to pass the - argument on the stack. - - The value of the expression can also be a 'parallel' RTX. This is - used when an argument is passed in multiple locations. The mode of - the 'parallel' should be the mode of the entire argument. The - 'parallel' holds any number of 'expr_list' pairs; each one - describes where part of the argument is passed. In each - 'expr_list' the first operand must be a '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 'expr_list' is a 'const_int' which - gives the offset in bytes into the entire argument of where this - part starts. As a special exception the first 'expr_list' in the - '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 hook is called, it is called with 'MODE == - VOIDmode', and its result is passed to the 'call' or 'call_value' - pattern as operands 2 and 3 respectively. - - The usual way to make the ISO library '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 'TARGET_FUNCTION_ARG' return 0 whenever NAMED is 'false'. - - You may use the hook '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 'REG_PARM_STACK_SPACE' is not - defined and 'TARGET_FUNCTION_ARG' returns nonzero for such an - argument, the compiler will abort. If 'REG_PARM_STACK_SPACE' is - defined, the argument will be computed in the stack and then loaded - into a register. - - -- Target Hook: bool TARGET_MUST_PASS_IN_STACK (enum machine_mode MODE, - const_tree TYPE) - This target hook should return 'true' if we should not pass TYPE - solely in registers. The file 'expr.h' defines a definition that - is usually appropriate, refer to 'expr.h' for additional - documentation. - - -- Target Hook: rtx TARGET_FUNCTION_INCOMING_ARG (cumulative_args_t CA, - enum machine_mode MODE, const_tree TYPE, bool NAMED) - Define this hook 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, 'TARGET_FUNCTION_ARG' computes the register in - which the caller passes the value, and - 'TARGET_FUNCTION_INCOMING_ARG' should be defined in a similar - fashion to tell the function being called where the arguments will - arrive. - - If 'TARGET_FUNCTION_INCOMING_ARG' is not defined, - 'TARGET_FUNCTION_ARG' serves both purposes. - - -- Target Hook: int TARGET_ARG_PARTIAL_BYTES (cumulative_args_t CUM, - enum machine_mode MODE, tree TYPE, bool 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 '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. - - 'TARGET_FUNCTION_ARG' for these arguments should return the first - register to be used by the caller for this argument; likewise - 'TARGET_FUNCTION_INCOMING_ARG', for the called function. - - -- Target Hook: bool TARGET_PASS_BY_REFERENCE (cumulative_args_t CUM, - enum machine_mode MODE, const_tree TYPE, bool NAMED) - This target hook should return 'true' if an argument at the - position indicated by CUM should be passed by reference. This - predicate is queried after target independent reasons for being - passed by reference, such as '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. - - -- Target Hook: bool TARGET_CALLEE_COPIES (cumulative_args_t CUM, enum - machine_mode MODE, const_tree TYPE, bool 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. - - -- Macro: CUMULATIVE_ARGS - A C type for declaring a variable that is used as the first - argument of 'TARGET_FUNCTION_ARG' and other related values. For - some target machines, the type 'int' suffices and can hold the - number of bytes of argument so far. - - There is no need to record in '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 'CUMULATIVE_ARGS'; however, the data structure - must exist and should not be empty, so use 'int'. - - -- Macro: OVERRIDE_ABI_FORMAT (FNDECL) - If defined, this macro is called before generating any code for a - function, but after the CFUN descriptor for the function has been - created. The back end may use this macro to update CFUN to reflect - an ABI other than that which would normally be used by default. If - the compiler is generating code for a compiler-generated function, - FNDECL may be 'NULL'. - - -- Macro: INIT_CUMULATIVE_ARGS (CUM, FNTYPE, LIBNAME, FNDECL, - N_NAMED_ARGS) - A C statement (sans semicolon) for initializing the variable CUM - for the state at the beginning of the argument list. The variable - has type 'CUMULATIVE_ARGS'. The value of 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, FNDECL contain the declaration node of - the function. FNDECL is also set when 'INIT_CUMULATIVE_ARGS' is - used to find arguments for the function being compiled. - 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, N_NAMED_ARGS is - set to -1. - - When processing a call to a compiler support library function, - LIBNAME identifies which one. It is a 'symbol_ref' rtx which - contains the name of the function, as a string. LIBNAME is 0 when - an ordinary C function call is being processed. Thus, each time - this macro is called, either LIBNAME or FNTYPE is nonzero, but - never both of them at once. - - -- Macro: INIT_CUMULATIVE_LIBCALL_ARGS (CUM, MODE, LIBNAME) - Like 'INIT_CUMULATIVE_ARGS' but only used for outgoing libcalls, it - gets a 'MODE' argument instead of FNTYPE, that would be 'NULL'. - INDIRECT would always be zero, too. If this macro is not defined, - 'INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname, 0)' is used instead. - - -- Macro: INIT_CUMULATIVE_INCOMING_ARGS (CUM, FNTYPE, LIBNAME) - Like 'INIT_CUMULATIVE_ARGS' but overrides it for the purposes of - finding the arguments for the function being compiled. If this - macro is undefined, 'INIT_CUMULATIVE_ARGS' is used instead. - - The value passed for LIBNAME is always 0, since library routines - with special calling conventions are never compiled with GCC. The - argument LIBNAME exists for symmetry with 'INIT_CUMULATIVE_ARGS'. - - -- Target Hook: void TARGET_FUNCTION_ARG_ADVANCE (cumulative_args_t CA, - enum machine_mode MODE, const_tree TYPE, bool NAMED) - This hook updates the summarizer variable pointed to by CA to - advance past an argument in the argument list. The values MODE, - TYPE and NAMED describe that argument. Once this is done, the - variable CUM is suitable for analyzing the _following_ argument - with 'TARGET_FUNCTION_ARG', etc. - - This hook 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. - - -- Macro: FUNCTION_ARG_OFFSET (MODE, TYPE) - If defined, a C expression that is the number of bytes to add to - the offset of the argument passed in memory. This is needed for - the SPU, which passes 'char' and 'short' arguments in the preferred - slot that is in the middle of the quad word instead of starting at - the top. - - -- Macro: FUNCTION_ARG_PADDING (MODE, 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 'enum direction': either 'upward' to pad above - the argument, 'downward' to pad below, or 'none' to inhibit - padding. - - The _amount_ of padding is not controlled by this macro, but by the - target hook 'TARGET_FUNCTION_ARG_ROUND_BOUNDARY'. It is always - just enough to reach the next multiple of that boundary. - - 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 'int', and upward - otherwise. - - -- Macro: 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 'PARM_BOUNDARY'. If this macro is not - defined, all such arguments are padded down if 'BYTES_BIG_ENDIAN' - is true. - - -- Macro: BLOCK_REG_PADDING (MODE, TYPE, FIRST) - Specify padding for the last element of a block move between - registers and memory. 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 - 'PARALLEL' rtl. In particular, '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. - - -- Target Hook: unsigned int TARGET_FUNCTION_ARG_BOUNDARY (enum - machine_mode MODE, const_tree TYPE) - This hook returns the alignment boundary, in bits, of an argument - with the specified mode and type. The default hook returns - 'PARM_BOUNDARY' for all arguments. - - -- Target Hook: unsigned int TARGET_FUNCTION_ARG_ROUND_BOUNDARY (enum - machine_mode MODE, const_tree TYPE) - Normally, the size of an argument is rounded up to 'PARM_BOUNDARY', - which is the default value for this hook. You can define this hook - to return a different value if an argument size must be rounded to - a larger value. - - -- Macro: FUNCTION_ARG_REGNO_P (REGNO) - A C expression that is nonzero if REGNO is the number of a hard - register in which function arguments are sometimes passed. This - does _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. - - -- Target Hook: bool TARGET_SPLIT_COMPLEX_ARG (const_tree TYPE) - This hook should return true if parameter of type 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 'NULL', which is treated as - always false. - - -- Target Hook: tree TARGET_BUILD_BUILTIN_VA_LIST (void) - This hook returns a type node for 'va_list' for the target. The - default version of the hook returns 'void*'. - - -- Target Hook: int TARGET_ENUM_VA_LIST_P (int IDX, const char **PNAME, - tree *PTREE) - This target hook is used in function 'c_common_nodes_and_builtins' - to iterate through the target specific builtin types for va_list. - The variable IDX is used as iterator. PNAME has to be a pointer to - a 'const char *' and PTREE a pointer to a 'tree' typed variable. - The arguments PNAME and PTREE are used to store the result of this - macro and are set to the name of the va_list builtin type and its - internal type. If the return value of this macro is zero, then - there is no more element. Otherwise the IDX should be increased - for the next call of this macro to iterate through all types. - - -- Target Hook: tree TARGET_FN_ABI_VA_LIST (tree FNDECL) - This hook returns the va_list type of the calling convention - specified by FNDECL. The default version of this hook returns - 'va_list_type_node'. - - -- Target Hook: tree TARGET_CANONICAL_VA_LIST_TYPE (tree TYPE) - This hook returns the va_list type of the calling convention - specified by the type of TYPE. If TYPE is not a valid va_list - type, it returns 'NULL_TREE'. - - -- Target Hook: tree TARGET_GIMPLIFY_VA_ARG_EXPR (tree VALIST, tree - TYPE, gimple_seq *PRE_P, gimple_seq *POST_P) - This hook performs target-specific gimplification of 'VA_ARG_EXPR'. - The first two parameters correspond to the arguments to 'va_arg'; - the latter two are as in 'gimplify.c:gimplify_expr'. - - -- Target Hook: bool TARGET_VALID_POINTER_MODE (enum machine_mode MODE) - Define this to return nonzero if the port can handle pointers with - machine mode MODE. The default version of this hook returns true - for both 'ptr_mode' and 'Pmode'. - - -- Target Hook: bool TARGET_REF_MAY_ALIAS_ERRNO (struct ao_ref *REF) - Define this to return nonzero if the memory reference REF may alias - with the system C library errno location. The default version of - this hook assumes the system C library errno location is either a - declaration of type int or accessed by dereferencing a pointer to - int. - - -- Target Hook: bool TARGET_SCALAR_MODE_SUPPORTED_P (enum machine_mode - MODE) - Define this to return nonzero if the port is prepared to handle - insns involving scalar mode 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 - 'optabs.c'. - - -- Target Hook: bool TARGET_VECTOR_MODE_SUPPORTED_P (enum machine_mode - MODE) - Define this to return nonzero if the port is prepared to handle - insns involving vector mode MODE. At the very least, it must have - move patterns for this mode. - - -- Target Hook: bool TARGET_ARRAY_MODE_SUPPORTED_P (enum machine_mode - MODE, unsigned HOST_WIDE_INT NELEMS) - Return true if GCC should try to use a scalar mode to store an - array of NELEMS elements, given that each element has mode MODE. - Returning true here overrides the usual 'MAX_FIXED_MODE' limit and - allows GCC to use any defined integer mode. - - One use of this hook is to support vector load and store operations - that operate on several homogeneous vectors. For example, ARM NEON - has operations like: - - int8x8x3_t vld3_s8 (const int8_t *) - - where the return type is defined as: - - typedef struct int8x8x3_t - { - int8x8_t val[3]; - } int8x8x3_t; - - If this hook allows 'val' to have a scalar mode, then 'int8x8x3_t' - can have the same mode. GCC can then store 'int8x8x3_t's in - registers rather than forcing them onto the stack. - - -- Target Hook: bool TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P (enum - machine_mode MODE) - Define this to return nonzero for machine modes for which the port - has small register classes. If this target hook returns nonzero - for a given MODE, the compiler will try to minimize the lifetime of - registers in MODE. The hook may be called with 'VOIDmode' as - argument. In this case, the hook is expected to return nonzero if - it returns nonzero for any mode. - - 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. - - Passes before reload do not know which hard registers will be used - in an instruction, but the machine modes of the registers set or - used in the instruction are already known. And for some machines, - register classes are small for, say, integer registers but not for - floating point registers. For example, the AMD x86-64 architecture - requires specific registers for the legacy x86 integer - instructions, but there are many SSE registers for floating point - operations. On such targets, a good strategy may be to return - nonzero from this hook for 'INTEGRAL_MODE_P' machine modes but zero - for the SSE register classes. - - The default version of this hook returns false for any mode. It is - always safe to redefine this hook to return 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 hook to return a nonzero value when it is required, the - compiler will run out of spill registers and print a fatal error - message. - - -- Target Hook: unsigned int TARGET_FLAGS_REGNUM - If the target has a dedicated flags register, and it needs to use - the post-reload comparison elimination pass, then this value should - be set appropriately. - - -File: gccint.info, Node: Scalar Return, Next: Aggregate Return, Prev: Register Arguments, Up: Stack and Calling - -17.10.8 How Scalar Function Values Are Returned ------------------------------------------------ - -This section discusses the macros that control returning scalars as -values--values that can fit in registers. - - -- Target Hook: rtx TARGET_FUNCTION_VALUE (const_tree RET_TYPE, - const_tree FN_DECL_OR_TYPE, bool OUTGOING) - - Define this to return an RTX representing the place where a - function returns or receives a value of data type RET_TYPE, a tree - node representing a data type. FN_DECL_OR_TYPE is a tree node - representing 'FUNCTION_DECL' or 'FUNCTION_TYPE' of a function being - called. If 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 'TYPE_MODE (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 'reg' RTX for the hard register where the return value is stored. - The value can also be a 'parallel' RTX, if the return value is in - multiple places. See 'TARGET_FUNCTION_ARG' for an explanation of - the 'parallel' form. Note that the callee will populate every - location specified in the 'parallel', but if the first element of - the 'parallel' contains the whole return value, callers will use - that element as the canonical location and ignore the others. The - m68k port uses this type of 'parallel' to return pointers in both - '%a0' (the canonical location) and '%d0'. - - If 'TARGET_PROMOTE_FUNCTION_RETURN' returns true, you must apply - the same promotion rules specified in 'PROMOTE_MODE' if VALTYPE is - a scalar type. - - If the precise function being called is known, FUNC is a tree node - ('FUNCTION_DECL') for it; otherwise, 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 OUTGOING. - - 'TARGET_FUNCTION_VALUE' is not used for return values with - aggregate data types, because these are returned in another way. - See 'TARGET_STRUCT_VALUE_RTX' and related macros, below. - - -- Macro: FUNCTION_VALUE (VALTYPE, FUNC) - This macro has been deprecated. Use 'TARGET_FUNCTION_VALUE' for a - new target instead. - - -- Macro: LIBCALL_VALUE (MODE) - A C expression to create an RTX representing the place where a - library function returns a value of mode MODE. - - 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. - - -- Target Hook: rtx TARGET_LIBCALL_VALUE (enum machine_mode MODE, - const_rtx FUN) - Define this hook if the back-end needs to know the name of the - libcall function in order to determine where the result should be - returned. - - The mode of the result is given by MODE and the name of the called - library function is given by FUN. The hook should return an RTX - representing the place where the library function result will be - returned. - - If this hook is not defined, then LIBCALL_VALUE will be used. - - -- Macro: FUNCTION_VALUE_REGNO_P (REGNO) - A C expression that is nonzero if 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 'double', say) need not - be recognized by this macro. So for most machines, this definition - suffices: - - #define FUNCTION_VALUE_REGNO_P(N) ((N) == 0) - - 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. - - This macro has been deprecated. Use - 'TARGET_FUNCTION_VALUE_REGNO_P' for a new target instead. - - -- Target Hook: bool TARGET_FUNCTION_VALUE_REGNO_P (const unsigned int - REGNO) - A target hook that return 'true' if 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 'double', say) need not - be recognized by this target hook. - - If the machine has register windows, so that the caller and the - called function use different registers for the return value, this - target hook should recognize only the caller's register numbers. - - If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be - used. - - -- Macro: APPLY_RESULT_SIZE - Define this macro if 'untyped_call' and 'untyped_return' need more - space than is implied by 'FUNCTION_VALUE_REGNO_P' for saving and - restoring an arbitrary return value. - - -- Target Hook: bool TARGET_RETURN_IN_MSB (const_tree TYPE) - This hook should return true if values of type 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 TYPE is - returned in a register; the caller is required to check this. - - Note that the register provided by '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, 'TARGET_FUNCTION_VALUE' should provide an 'SImode' - rtx. - - -File: gccint.info, Node: Aggregate Return, Next: Caller Saves, Prev: Scalar Return, Up: Stack and Calling - -17.10.9 How Large Values Are Returned -------------------------------------- - -When a function value's mode is 'BLKmode' (and in some other cases), the -value is not returned according to 'TARGET_FUNCTION_VALUE' (*note 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 -"structure value address". - - This section describes how to control returning structure values in -memory. - - -- Target Hook: bool TARGET_RETURN_IN_MEMORY (const_tree TYPE, - const_tree 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 TYPE will be the data type of the value, and FNTYPE - will be the type of the function doing the returning, or 'NULL' for - libcalls. - - Note that values of mode 'BLKmode' must be explicitly handled by - this function. Also, the 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 '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 - 'DEFAULT_PCC_STRUCT_RETURN' to indicate this. - - -- Macro: 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 'TARGET_RETURN_IN_MEMORY' target hook. - - If not defined, this defaults to the value 1. - - -- Target Hook: rtx TARGET_STRUCT_VALUE_RTX (tree FNDECL, int INCOMING) - This target hook should return the location of the structure value - address (normally a 'mem' or 'reg'), or 0 if the address is passed - as an "invisible" first argument. Note that FNDECL may be '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. - INCOMING is '1' or '2' when the location is needed in the context - of the called function, and '0' in the context of the caller. - - If INCOMING is nonzero and the address is to be found on the stack, - return a 'mem' which refers to the frame pointer. If INCOMING is - '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. - - -- Macro: 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 '-fpcc-struct-return' mode, but it does - nothing when you use '-freg-struct-return' mode. - - -- Target Hook: enum machine_mode TARGET_GET_RAW_RESULT_MODE (int - REGNO) - This target hook returns the mode to be used when accessing raw - return registers in '__builtin_return'. Define this macro if the - value in REG_RAW_MODE is not correct. - - -- Target Hook: enum machine_mode TARGET_GET_RAW_ARG_MODE (int REGNO) - This target hook returns the mode to be used when accessing raw - argument registers in '__builtin_apply_args'. Define this macro if - the value in REG_RAW_MODE is not correct. - - -File: gccint.info, Node: Caller Saves, Next: Function Entry, Prev: Aggregate Return, Up: Stack and Calling - -17.10.10 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. - - -- Macro: CALLER_SAVE_PROFITABLE (REFS, 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: '4 * CALLS < REFS'. - - -- Macro: HARD_REGNO_CALLER_SAVE_MODE (REGNO, NREGS) - A C expression specifying which mode is required for saving NREGS - of a pseudo-register in call-clobbered hard register REGNO. If - REGNO is unsuitable for caller save, 'VOIDmode' should be returned. - For most machines this macro need not be defined since GCC will - select the smallest suitable mode. - - -File: gccint.info, Node: Function Entry, Next: Profiling, Prev: Caller Saves, Up: Stack and Calling - -17.10.11 Function Entry and Exit --------------------------------- - -This section describes the macros that output function entry -("prologue") and exit ("epilogue") code. - - -- Target Hook: void TARGET_ASM_FUNCTION_PROLOGUE (FILE *FILE, - HOST_WIDE_INT 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 SIZE additional bytes of storage - for the local variables. SIZE is an integer. 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. - - To determine which registers to save, the macro can refer to the - array 'regs_ever_live': element R is nonzero if hard register R is - used anywhere within the function. This implies the function - prologue should save register R, provided it is not one of the - call-used registers. ('TARGET_ASM_FUNCTION_EPILOGUE' must likewise - use '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. - - 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 - 'frame_pointer_needed'. The variable's value will be 1 at run time - in a function that needs a frame pointer. *Note 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 '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. - - -- Target Hook: void TARGET_ASM_FUNCTION_END_PROLOGUE (FILE *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. *Note prologue instruction pattern::. - - -- Target Hook: void TARGET_ASM_FUNCTION_BEGIN_EPILOGUE (FILE *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. *Note epilogue instruction pattern::. - - -- Target Hook: void TARGET_ASM_FUNCTION_EPILOGUE (FILE *FILE, - HOST_WIDE_INT 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 'TARGET_ASM_FUNCTION_PROLOGUE', and - the registers to restore are determined from 'regs_ever_live' and - '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 'return' and do not define the macro - 'TARGET_ASM_FUNCTION_EPILOGUE' at all. - - Do not define a pattern named 'return' if you want the - 'TARGET_ASM_FUNCTION_EPILOGUE' to be used. If you want the target - switches to control whether return instructions or epilogues are - used, define a 'return' pattern with a validity condition that - tests the target switches appropriately. If the '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 - 'frame_pointer_needed'. The variable's value will be 1 when - compiling a function that needs a frame pointer. - - Normally, 'TARGET_ASM_FUNCTION_PROLOGUE' and - 'TARGET_ASM_FUNCTION_EPILOGUE' must treat leaf functions specially. - The C variable 'current_function_is_leaf' is nonzero for such a - function. *Note 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 '-mrtd' pops arguments in functions that take a fixed - number of arguments. - - Your definition of the macro 'RETURN_POPS_ARGS' decides which - functions pop their own arguments. 'TARGET_ASM_FUNCTION_EPILOGUE' - needs to know what was decided. The number of bytes of the current - function's arguments that this function should pop is available in - 'crtl->args.pops_args'. *Note Scalar Return::. - - * A region of 'crtl->args.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 '<stdarg.h>'. - - * 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. - - * A region of at least 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. - - * Optionally, when 'ACCUMULATE_OUTGOING_ARGS' is defined, a region of - 'crtl->outgoing_args_size' bytes to be used for outgoing argument - lists of the function. *Note Stack Arguments::. - - -- Macro: 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 'EXIT_IGNORE_STACK'. - - -- Macro: EPILOGUE_USES (REGNO) - Define this macro as a C expression that is nonzero for registers - that are used by the epilogue or the 'return' pattern. The stack - and frame pointer registers are already assumed to be used as - needed. - - -- Macro: EH_USES (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. - - -- Target Hook: void TARGET_ASM_OUTPUT_MI_THUNK (FILE *FILE, tree - THUNK_FNDECL, HOST_WIDE_INT DELTA, HOST_WIDE_INT VCALL_OFFSET, - tree 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 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 'this' pointer - in C++. This is the incoming argument _before_ the function - prologue, e.g. '%o0' on a sparc. The addition must preserve the - values of all other incoming arguments. - - Then, if VCALL_OFFSET is nonzero, an additional adjustment should - be made after adding 'delta'. In particular, if P is the adjusted - pointer, the following adjustment should be made: - - p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)] - - After the additions, emit code to jump to FUNCTION, which is a - 'FUNCTION_DECL'. This is a direct pure jump, not a call, and does - not touch the return address. Hence returning from FUNCTION will - return to whoever called the current 'thunk'. - - The effect must be as if FUNCTION had been called directly with the - adjusted first argument. This macro is responsible for emitting - all of the code for a thunk function; - 'TARGET_ASM_FUNCTION_PROLOGUE' and 'TARGET_ASM_FUNCTION_EPILOGUE' - are not invoked. - - The THUNK_FNDECL is redundant. (DELTA and 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 FUNCTION instead of jumping to it. The generic approach does - not support varargs. - - -- Target Hook: bool TARGET_ASM_CAN_OUTPUT_MI_THUNK (const_tree - THUNK_FNDECL, HOST_WIDE_INT DELTA, HOST_WIDE_INT VCALL_OFFSET, - const_tree 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. - - -File: gccint.info, Node: Profiling, Next: Tail Calls, Prev: Function Entry, Up: Stack and Calling - -17.10.12 Generating Code for Profiling --------------------------------------- - -These macros will help you generate code for profiling. - - -- Macro: FUNCTION_PROFILER (FILE, LABELNO) - A C statement or compound statement to output to FILE some - assembler code to call the profiling subroutine 'mcount'. - - The details of how '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 'mcount' expect the address of a counter - variable to be loaded into some register. The name of this - variable is 'LP' followed by the number LABELNO, so you would - generate the name using 'LP%d' in a 'fprintf'. - - -- Macro: PROFILE_HOOK - A C statement or compound statement to output to FILE some assembly - code to call the profiling subroutine 'mcount' even the target does - not support profiling. - - -- Macro: NO_PROFILE_COUNTERS - Define this macro to be an expression with a nonzero value if the - '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 - LABELNO argument to 'FUNCTION_PROFILER'. - - -- Macro: PROFILE_BEFORE_PROLOGUE - Define this macro if the code for function profiling should come - before the function prologue. Normally, the profiling code comes - after. - - -File: gccint.info, Node: Tail Calls, Next: Stack Smashing Protection, Prev: Profiling, Up: Stack and Calling - -17.10.13 Permitting tail calls ------------------------------- - - -- Target Hook: bool TARGET_FUNCTION_OK_FOR_SIBCALL (tree DECL, tree - EXP) - True if it is OK to do sibling call optimization for the specified - call expression EXP. DECL will be the called function, or '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 '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. - - -- Target Hook: void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap REGS) - Add any hard registers to 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. - - -- Target Hook: void TARGET_SET_UP_BY_PROLOGUE (struct - hard_reg_set_container *) - This hook should add additional registers that are computed by the - prologue to the hard regset for shrink-wrapping optimization - purposes. - - -- Target Hook: bool TARGET_WARN_FUNC_RETURN (tree) - True if a function's return statements should be checked for - matching the function's return type. This includes checking for - falling off the end of a non-void function. Return false if no - such check should be made. - - -File: gccint.info, Node: Stack Smashing Protection, Prev: Tail Calls, Up: Stack and Calling - -17.10.14 Stack smashing protection ----------------------------------- - - -- Target Hook: tree TARGET_STACK_PROTECT_GUARD (void) - This hook returns a '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 'ptr_type_node'. - - The default version of this hook creates a variable called - '__stack_chk_guard', which is normally defined in 'libgcc2.c'. - - -- Target Hook: tree TARGET_STACK_PROTECT_FAIL (void) - This hook returns a 'CALL_EXPR' that alerts the runtime that the - stack protect guard variable has been modified. This expression - should involve a call to a 'noreturn' function. - - The default version of this hook invokes a function called - '__stack_chk_fail', taking no arguments. This function is normally - defined in 'libgcc2.c'. - - -- Common Target Hook: bool TARGET_SUPPORTS_SPLIT_STACK (bool REPORT, - struct gcc_options *OPTS) - Whether this target supports splitting the stack when the options - described in OPTS have been passed. This is called after options - have been parsed, so the target may reject splitting the stack in - some configurations. The default version of this hook returns - false. If REPORT is true, this function may issue a warning or - error; if REPORT is false, it must simply return a value - - -File: gccint.info, Node: Varargs, Next: Trampolines, Prev: Stack and Calling, Up: Target Macros - -17.11 Implementing the Varargs Macros -===================================== - -GCC comes with an implementation of '<varargs.h>' and '<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 '<stdarg.h>' differs from traditional '<varargs.h>' mainly in the -calling convention for 'va_start'. The traditional implementation takes -just one argument, which is the variable in which to store the argument -pointer. The ISO implementation of 'va_start' takes an additional -second argument. The user is supposed to write the last named argument -of the function here. - - However, '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. - - -- Macro: __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 'va_start' must use '__builtin_saveregs', - unless you use 'TARGET_SETUP_INCOMING_VARARGS' (see below) instead. - - On some machines, '__builtin_saveregs' is open-coded under the - control of the target hook 'TARGET_EXPAND_BUILTIN_SAVEREGS'. On - other machines, it calls a routine written in assembler language, - found in 'libgcc2.c'. - - Code generated for the call to '__builtin_saveregs' appears at the - beginning of the function, as opposed to where the call to - '__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. - - -- Macro: __builtin_next_arg (LASTARG) - This builtin returns the address of the first anonymous stack - argument, as type 'void *'. If 'ARGS_GROW_DOWNWARD', it returns - the address of the location above the first anonymous stack - argument. Use it in 'va_start' to initialize the pointer for - fetching arguments from the stack. Also use it in 'va_start' to - verify that the second parameter LASTARG is the last named argument - of the current function. - - -- Macro: __builtin_classify_type (OBJECT) - Since each machine has its own conventions for which data types are - passed in which kind of register, your implementation of 'va_arg' - has to embody these conventions. The easiest way to categorize the - specified data type is to use '__builtin_classify_type' together - with 'sizeof' and '__alignof__'. - - '__builtin_classify_type' ignores the value of 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 'typeclass.h' defines an enumeration that you can use to - interpret the values of '__builtin_classify_type'. - - These machine description macros help implement varargs: - - -- Target Hook: rtx TARGET_EXPAND_BUILTIN_SAVEREGS (void) - If defined, this hook produces the machine-specific code for a call - to '__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 '__builtin_saveregs'. - - -- Target Hook: void TARGET_SETUP_INCOMING_VARARGS (cumulative_args_t - ARGS_SO_FAR, enum machine_mode MODE, tree TYPE, int - *PRETEND_ARGS_SIZE, int SECOND_TIME) - This target hook offers an alternative to using - '__builtin_saveregs' and defining the hook - '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 ARGS_SO_FAR points to the 'CUMULATIVE_ARGS' data - structure, containing the values that are obtained after processing - the named arguments. The arguments MODE and 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 _not_ used for the named arguments, and - second, store the size of the data thus pushed into the - 'int'-valued variable pointed to by 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, - '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 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 - 'TARGET_SETUP_INCOMING_VARARGS' should not generate any - instructions in this case. - - -- Target Hook: bool TARGET_STRICT_ARGUMENT_NAMING (cumulative_args_t - CA) - Define this hook to return '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 NAMED argument to 'TARGET_FUNCTION_ARG' - is set for varargs and stdarg functions. If this hook returns - 'true', the NAMED argument is always true for named arguments, and - false for unnamed arguments. If it returns 'false', but - 'TARGET_PRETEND_OUTGOING_VARARGS_NAMED' returns '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 'false'. - - -- Target Hook: bool TARGET_PRETEND_OUTGOING_VARARGS_NAMED - (cumulative_args_t CA) - If you need to conditionally change ABIs so that one works with - 'TARGET_SETUP_INCOMING_VARARGS', but the other works like neither - 'TARGET_SETUP_INCOMING_VARARGS' nor 'TARGET_STRICT_ARGUMENT_NAMING' - was defined, then define this hook to return 'true' if - 'TARGET_SETUP_INCOMING_VARARGS' is used, 'false' otherwise. - Otherwise, you should not define this hook. - - -File: gccint.info, Node: Trampolines, Next: Library Calls, Prev: Varargs, Up: Target Macros - -17.12 Trampolines for Nested Functions -====================================== - -A "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. - - -- Target Hook: void TARGET_ASM_TRAMPOLINE_TEMPLATE (FILE *F) - This hook is called by 'assemble_trampoline_template' to output, on - the stream F, 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 hook, it means no template is needed for - the target. Do not define this hook 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. - - -- Macro: TRAMPOLINE_SECTION - Return the section into which the trampoline template is to be - placed (*note Sections::). The default value is - 'readonly_data_section'. - - -- Macro: TRAMPOLINE_SIZE - A C expression for the size in bytes of the trampoline, as an - integer. - - -- Macro: TRAMPOLINE_ALIGNMENT - Alignment required for trampolines, in bits. - - If you don't define this macro, the value of 'FUNCTION_ALIGNMENT' - is used for aligning trampolines. - - -- Target Hook: void TARGET_TRAMPOLINE_INIT (rtx M_TRAMP, tree FNDECL, - rtx STATIC_CHAIN) - This hook is called to initialize a trampoline. M_TRAMP is an RTX - for the memory block for the trampoline; FNDECL is the - 'FUNCTION_DECL' for the nested function; STATIC_CHAIN is an RTX for - the static chain value that should be passed to the function when - it is called. - - If the target defines 'TARGET_ASM_TRAMPOLINE_TEMPLATE', then the - first thing this hook should do is emit a block move into M_TRAMP - from the memory block returned by 'assemble_trampoline_template'. - Note that the block move need only cover the constant parts of the - trampoline. If the target isolates the variable parts of the - trampoline to the end, not all 'TRAMPOLINE_SIZE' bytes need be - copied. - - If the target requires any other actions, such as flushing caches - or enabling stack execution, these actions should be performed - after initializing the trampoline proper. - - -- Target Hook: rtx TARGET_TRAMPOLINE_ADJUST_ADDRESS (rtx ADDR) - This hook should perform any machine-specific adjustment in the - address of the trampoline. Its argument contains the address of - the memory block that was passed to 'TARGET_TRAMPOLINE_INIT'. In - case the address to be used for a function call should be different - from the address at which the template was stored, the different - address should be returned; otherwise ADDR should be returned - unchanged. If this hook is not defined, ADDR will be used for - function calls. - - 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. - - -- Macro: CLEAR_INSN_CACHE (BEG, END) - If defined, expands to a C expression clearing the _instruction - cache_ in the specified interval. The definition of this macro - would typically be a series of 'asm' statements. Both BEG and END - are both pointer expressions. - - 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 'm68k.h' as a guide. - - -- Macro: TRANSFER_FROM_TRAMPOLINE - Define this macro if trampolines need a special subroutine to do - their work. The macro should expand to a series of 'asm' - statements which will be compiled with GCC. They go in a library - function named '__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 '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. - - -File: gccint.info, Node: Library Calls, Next: Addressing Modes, Prev: Trampolines, Up: Target Macros - -17.13 Implicit Calls to Library Routines -======================================== - -Here is an explanation of implicit calls to library routines. - - -- Macro: 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. - - -- Target Hook: void TARGET_INIT_LIBFUNCS (void) - This hook should declare additional library routines or rename - existing ones, using the functions 'set_optab_libfunc' and - 'init_one_libfunc' defined in 'optabs.c'. '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. - - -- Target Hook: bool TARGET_LIBFUNC_GNU_PREFIX - If false (the default), internal library routines start with two - underscores. If set to true, these routines start with '__gnu_' - instead. E.g., '__muldi3' changes to '__gnu_muldi3'. This - currently only affects functions defined in 'libgcc2.c'. If this - is set to true, the 'tm.h' file must also '#define - LIBGCC2_GNU_PREFIX'. - - -- Macro: FLOAT_LIB_COMPARE_RETURNS_BOOL (MODE, COMPARISON) - This macro should return 'true' if the library routine that - implements the floating point comparison operator COMPARISON in - mode MODE will return a boolean, and 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. - - -- Macro: TARGET_LIB_INT_CMP_BIASED - This macro should evaluate to 'true' if the integer comparison - functions (like '__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 'false' the comparison - functions return -1, 0, and 1 instead of 0, 1, and 2. If the - target uses the routines in 'libgcc.a', you do not need to define - this macro. - - -- Macro: TARGET_HAS_NO_HW_DIVIDE - This macro should be defined if the target has no hardware divide - instructions. If this macro is defined, GCC will use an algorithm - which make use of simple logical and arithmetic operations for - 64-bit division. If the macro is not defined, GCC will use an - algorithm which make use of a 64-bit by 32-bit divide primitive. - - -- Macro: TARGET_EDOM - The value of '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 'EDOM' into 'errno' directly. Look in - '/usr/include/errno.h' to find the value of 'EDOM' on your system. - - If you do not define '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 'matherr' - when there is an error, then you should leave 'TARGET_EDOM' - undefined so that 'matherr' is used normally. - - -- Macro: GEN_ERRNO_RTX - Define this macro as a C expression to create an rtl expression - that refers to the global "variable" 'errno'. (On certain systems, - 'errno' may not actually be a variable.) If you don't define this - macro, a reasonable default is used. - - -- Target Hook: bool TARGET_LIBC_HAS_FUNCTION (enum function_class - FN_CLASS) - This hook determines whether a function from a class of functions - FN_CLASS is present at the runtime. - - -- Macro: NEXT_OBJC_RUNTIME - Set this macro to 1 to use the "NeXT" Objective-C message sending - conventions by default. This calling convention involves passing - the object, the selector and the method arguments all at once to - the method-lookup library function. This is the usual setting when - targeting Darwin/Mac OS X systems, which have the NeXT runtime - installed. - - If the macro is set to 0, the "GNU" Objective-C message sending - convention will be used by default. This convention passes just - the object and the selector to the method-lookup function, which - returns a pointer to the method. - - In either case, it remains possible to select code-generation for - the alternate scheme, by means of compiler command line switches. - - -File: gccint.info, Node: Addressing Modes, Next: Anchored Addresses, Prev: Library Calls, Up: Target Macros - -17.14 Addressing Modes -====================== - -This is about addressing modes. - - -- Macro: HAVE_PRE_INCREMENT - -- Macro: HAVE_PRE_DECREMENT - -- Macro: HAVE_POST_INCREMENT - -- Macro: HAVE_POST_DECREMENT - A C expression that is nonzero if the machine supports - pre-increment, pre-decrement, post-increment, or post-decrement - addressing respectively. - - -- Macro: HAVE_PRE_MODIFY_DISP - -- Macro: 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. - - -- Macro: HAVE_PRE_MODIFY_REG - -- Macro: 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. - - -- Macro: CONSTANT_ADDRESS_P (X) - A C expression that is 1 if the RTX X is a constant which is a - valid address. On most machines the default definition of - '(CONSTANT_P (X) && GET_CODE (X) != CONST_DOUBLE)' is acceptable, - but a few machines are more restrictive as to which constant - addresses are supported. - - -- Macro: CONSTANT_P (X) - 'CONSTANT_P', which is defined by target-independent code, accepts - integer-values expressions whose values are not explicitly known, - such as 'symbol_ref', 'label_ref', and 'high' expressions and - 'const' arithmetic expressions, in addition to 'const_int' and - 'const_double' expressions. - - -- Macro: 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 'TARGET_LEGITIMATE_ADDRESS_P' - would ever accept. - - -- Target Hook: bool TARGET_LEGITIMATE_ADDRESS_P (enum machine_mode - MODE, rtx X, bool STRICT) - A function that returns whether X (an RTX) is a legitimate memory - address on the target machine for a memory operand of mode MODE. - - Legitimate addresses are defined in two variants: a strict variant - and a non-strict one. The STRICT parameter chooses which variant - is desired by the caller. - - 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. This is because in - contexts where some kind of register is required, a pseudo-register - with no hard register must be rejected. For non-hard registers, - the strict variant should look up the 'reg_renumber' array; it - should then proceed using the hard register number in the array, or - treat the pseudo as a memory reference if the array holds '-1'. - - 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. - - Normally, constant addresses which are the sum of a 'symbol_ref' - and an integer are stored inside a '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 'const' as legitimate. - - Usually 'PRINT_OPERAND_ADDRESS' is not prepared to handle constant - sums that are not marked with 'const'. It assumes that a naked - 'plus' indicates indexing. If so, then you _must_ reject such - naked constant sums as illegitimate addresses, so that none of them - will be given to 'PRINT_OPERAND_ADDRESS'. - - 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 'TARGET_ENCODE_SECTION_INFO' to store the - information into the 'symbol_ref', and then check for it here. - When you see a 'const', you will have to look inside it to find the - 'symbol_ref' in order to determine the section. *Note Assembler - Format::. - - Some ports are still using a deprecated legacy substitute for this - hook, the 'GO_IF_LEGITIMATE_ADDRESS' macro. This macro has this - syntax: - - #define GO_IF_LEGITIMATE_ADDRESS (MODE, X, LABEL) - - and should 'goto LABEL' if the address X is a valid address on the - target machine for a memory operand of mode MODE. - - Compiler source files that want to use the strict variant of this - macro define the macro 'REG_OK_STRICT'. You should use an '#ifdef - REG_OK_STRICT' conditional to define the strict variant in that - case and the non-strict variant otherwise. - - Using the hook is usually simpler because it limits the number of - files that are recompiled when changes are made. - - -- Macro: TARGET_MEM_CONSTRAINT - A single character to be used instead of the default ''m'' - character for general memory addresses. This defines the - constraint letter which matches the memory addresses accepted by - 'TARGET_LEGITIMATE_ADDRESS_P'. Define this macro if you want to - support new address formats in your back end without changing the - semantics of the ''m'' constraint. This is necessary in order to - preserve functionality of inline assembly constructs using the - ''m'' constraint. - - -- Macro: FIND_BASE_TERM (X) - A C expression to determine the base term of address X, or to - provide a simplified version of X from which 'alias.c' can easily - find the base term. This macro is used in only two places: - 'find_base_value' and '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. - - -- Target Hook: rtx TARGET_LEGITIMIZE_ADDRESS (rtx X, rtx OLDX, enum - machine_mode MODE) - This hook is given an invalid memory address X for an operand of - mode MODE and should try to return a valid memory address. - - X will always be the result of a call to 'break_out_memory_refs', - and OLDX will be the operand that was given to that function to - produce X. - - The code of the hook should not alter the substructure of X. If it - transforms X into a more legitimate form, it should return the new - X. - - It is not necessary for this hook to come up with a legitimate - address, with the exception of native TLS addresses (*note Emulated - TLS::). The compiler has standard ways of doing so in all cases. - In fact, if the target supports only emulated TLS, it is safe to - omit this hook or make it return X if it cannot find a valid way to - legitimize the address. But often a machine-dependent strategy can - generate better code. - - -- Macro: LEGITIMIZE_RELOAD_ADDRESS (X, MODE, OPNUM, TYPE, IND_LEVELS, - WIN) - A C compound statement that attempts to replace X, which is an - address that needs reloading, with a valid memory address for an - operand of mode MODE. 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 'LEGITIMIZE_RELOAD_ADDRESS' appropriately, the - intermediate addresses generated for adjacent some stack slots can - be made identical, and thus be shared. - - _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. - - _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. - - The macro definition should use 'push_reload' to indicate parts - that need reloading; OPNUM, TYPE and IND_LEVELS are usually - suitable to be passed unaltered to 'push_reload'. - - The code generated by this macro must not alter the substructure of - X. If it transforms X into a more legitimate form, it should - assign X (which will always be a C variable) a new value. This - also applies to parts that you change indirectly by calling - 'push_reload'. - - The macro definition may use 'strict_memory_address_p' to test if - the address has become legitimate. - - If you want to change only a part of X, one standard way of doing - this is to use 'copy_rtx'. Note, however, that it 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. - - -- Target Hook: bool TARGET_MODE_DEPENDENT_ADDRESS_P (const_rtx ADDR, - addr_space_t ADDRSPACE) - This hook returns 'true' if memory address ADDR in address space - ADDRSPACE 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 ADDR is a valid address for the machine. - - The default version of this hook returns 'false'. - - -- Target Hook: bool TARGET_LEGITIMATE_CONSTANT_P (enum machine_mode - MODE, rtx X) - This hook returns true if X is a legitimate constant for a - MODE-mode immediate operand on the target machine. You can assume - that X satisfies 'CONSTANT_P', so you need not check this. - - The default definition returns true. - - -- Target Hook: rtx TARGET_DELEGITIMIZE_ADDRESS (rtx X) - This hook is used to undo the possibly obfuscating effects of the - 'LEGITIMIZE_ADDRESS' and 'LEGITIMIZE_RELOAD_ADDRESS' target macros. - Some backend implementations of these macros wrap symbol references - inside an 'UNSPEC' rtx to represent PIC or similar addressing - modes. This target hook allows GCC's optimizers to understand the - semantics of these opaque 'UNSPEC's by converting them back into - their original form. - - -- Target Hook: bool TARGET_CONST_NOT_OK_FOR_DEBUG_P (rtx X) - This hook should return true if X should not be emitted into debug - sections. - - -- Target Hook: bool TARGET_CANNOT_FORCE_CONST_MEM (enum machine_mode - MODE, rtx X) - This hook should return true if X is of a form that cannot (or - should not) be spilled to the constant pool. MODE is the mode of - X. - - 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. - - -- Target Hook: bool TARGET_USE_BLOCKS_FOR_CONSTANT_P (enum - machine_mode MODE, const_rtx X) - This hook should return true if pool entries for constant X can be - placed in an 'object_block' structure. MODE is the mode of X. - - The default version returns false for all constants. - - -- Target Hook: bool TARGET_USE_BLOCKS_FOR_DECL_P (const_tree DECL) - This hook should return true if pool entries for DECL should be - placed in an 'object_block' structure. - - The default version returns true for all decls. - - -- Target Hook: tree TARGET_BUILTIN_RECIPROCAL (unsigned FN, bool - MD_FN, bool SQRT) - This hook should return the DECL of a function that implements - reciprocal of the builtin function with builtin function code FN, - or 'NULL_TREE' if such a function is not available. MD_FN is true - when FN is a code of a machine-dependent builtin function. When - SQRT is true, additional optimizations that apply only to the - reciprocal of a square root function are performed, and only - reciprocals of 'sqrt' function are valid. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void) - This hook should return the DECL of a function F that given an - address ADDR as an argument returns a mask M that can be used to - extract from two vectors the relevant data that resides in ADDR in - case ADDR is not properly aligned. - - The autovectorizer, when vectorizing a load operation from an - address ADDR that may be unaligned, will generate two vector loads - from the two aligned addresses around ADDR. It then generates a - 'REALIGN_LOAD' operation to extract the relevant data from the two - loaded vectors. The first two arguments to 'REALIGN_LOAD', V1 and - V2, are the two vectors, each of size VS, and the third argument, - OFF, defines how the data will be extracted from these two vectors: - if OFF is 0, then the returned vector is V2; otherwise, the - returned vector is composed from the last VS-OFF elements of V1 - concatenated to the first OFF elements of V2. - - If this hook is defined, the autovectorizer will generate a call to - F (using the DECL tree that this hook returns) and will use the - return value of F as the argument OFF to 'REALIGN_LOAD'. - Therefore, the mask M returned by F should comply with the - semantics expected by 'REALIGN_LOAD' described above. If this hook - is not defined, then ADDR will be used as the argument OFF to - 'REALIGN_LOAD', in which case the low log2(VS) - 1 bits of ADDR - will be considered. - - -- Target Hook: int TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST (enum - vect_cost_for_stmt TYPE_OF_COST, tree VECTYPE, int MISALIGN) - Returns cost of different scalar or vector statements for - vectorization cost model. For vector memory operations the cost - may depend on type (VECTYPE) and misalignment value (MISALIGN). - - -- Target Hook: bool TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE - (const_tree TYPE, bool IS_PACKED) - Return true if vector alignment is reachable (by peeling N - iterations) for the given type. - - -- Target Hook: bool TARGET_VECTORIZE_VEC_PERM_CONST_OK (enum - MACHINE_MODE, const unsigned char *SEL) - Return true if a vector created for 'vec_perm_const' is valid. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_CONVERSION (unsigned - CODE, tree DEST_TYPE, tree SRC_TYPE) - This hook should return the DECL of a function that implements - conversion of the input vector of type SRC_TYPE to type DEST_TYPE. - The value of CODE is one of the enumerators in 'enum tree_code' and - specifies how the conversion is to be applied (truncation, - rounding, etc.). - - If this hook is defined, the autovectorizer will use the - 'TARGET_VECTORIZE_BUILTIN_CONVERSION' target hook when vectorizing - conversion. Otherwise, it will return 'NULL_TREE'. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION (tree - FNDECL, tree VEC_TYPE_OUT, tree VEC_TYPE_IN) - This hook should return the decl of a function that implements the - vectorized variant of the builtin function with builtin function - code CODE or 'NULL_TREE' if such a function is not available. The - value of FNDECL is the builtin function declaration. The return - type of the vectorized function shall be of vector type - VEC_TYPE_OUT and the argument types should be VEC_TYPE_IN. - - -- Target Hook: bool TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT (enum - machine_mode MODE, const_tree TYPE, int MISALIGNMENT, bool - IS_PACKED) - This hook should return true if the target supports misaligned - vector store/load of a specific factor denoted in the MISALIGNMENT - parameter. The vector store/load should be of machine mode MODE - and the elements in the vectors should be of type TYPE. IS_PACKED - parameter is true if the memory access is defined in a packed - struct. - - -- Target Hook: enum machine_mode TARGET_VECTORIZE_PREFERRED_SIMD_MODE - (enum machine_mode MODE) - This hook should return the preferred mode for vectorizing scalar - mode MODE. The default is equal to 'word_mode', because the - vectorizer can do some transformations even in absence of - specialized SIMD hardware. - - -- Target Hook: unsigned int - TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES (void) - This hook should return a mask of sizes that should be iterated - over after trying to autovectorize using the vector size derived - from the mode returned by 'TARGET_VECTORIZE_PREFERRED_SIMD_MODE'. - The default is zero which means to not iterate over other vector - sizes. - - -- Target Hook: void * TARGET_VECTORIZE_INIT_COST (struct loop - *LOOP_INFO) - This hook should initialize target-specific data structures in - preparation for modeling the costs of vectorizing a loop or basic - block. The default allocates three unsigned integers for - accumulating costs for the prologue, body, and epilogue of the loop - or basic block. If LOOP_INFO is non-NULL, it identifies the loop - being vectorized; otherwise a single block is being vectorized. - - -- Target Hook: unsigned TARGET_VECTORIZE_ADD_STMT_COST (void *DATA, - int COUNT, enum vect_cost_for_stmt KIND, struct _stmt_vec_info - *STMT_INFO, int MISALIGN, enum vect_cost_model_location WHERE) - This hook should update the target-specific DATA in response to - adding COUNT copies of the given KIND of statement to a loop or - basic block. The default adds the builtin vectorizer cost for the - copies of the statement to the accumulator specified by WHERE, (the - prologue, body, or epilogue) and returns the amount added. The - return value should be viewed as a tentative cost that may later be - revised. - - -- Target Hook: void TARGET_VECTORIZE_FINISH_COST (void *DATA, unsigned - *PROLOGUE_COST, unsigned *BODY_COST, unsigned *EPILOGUE_COST) - This hook should complete calculations of the cost of vectorizing a - loop or basic block based on DATA, and return the prologue, body, - and epilogue costs as unsigned integers. The default returns the - value of the three accumulators. - - -- Target Hook: void TARGET_VECTORIZE_DESTROY_COST_DATA (void *DATA) - This hook should release DATA and any related data structures - allocated by TARGET_VECTORIZE_INIT_COST. The default releases the - accumulator. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_TM_LOAD (tree) - This hook should return the built-in decl needed to load a vector - of the given type within a transaction. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_TM_STORE (tree) - This hook should return the built-in decl needed to store a vector - of the given type within a transaction. - - -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_GATHER (const_tree - MEM_VECTYPE, const_tree INDEX_TYPE, int SCALE) - Target builtin that implements vector gather operation. - MEM_VECTYPE is the vector type of the load and INDEX_TYPE is scalar - type of the index, scaled by SCALE. The default is 'NULL_TREE' - which means to not vectorize gather loads. - - -- Target Hook: int TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN - (struct cgraph_node *, struct cgraph_simd_clone *, TREE, INT) - This hook should set VECSIZE_MANGLE, VECSIZE_INT, VECSIZE_FLOAT - fields in SIMD_CLONE structure pointed by CLONE_INFO argument and - also SIMDLEN field if it was previously 0. The hook should return - 0 if SIMD clones shouldn't be emitted, or number of VECSIZE_MANGLE - variants that should be emitted. - - -- Target Hook: void TARGET_SIMD_CLONE_ADJUST (struct cgraph_node *) - This hook should add implicit 'attribute(target("..."))' attribute - to SIMD clone NODE if needed. - - -- Target Hook: int TARGET_SIMD_CLONE_USABLE (struct cgraph_node *) - This hook should return -1 if SIMD clone NODE shouldn't be used in - vectorized loops in current function, or non-negative number if it - is usable. In that case, the smaller the number is, the more - desirable it is to use it. - - -File: gccint.info, Node: Anchored Addresses, Next: Condition Code, Prev: Addressing Modes, Up: Target Macros - -17.15 Anchored Addresses -======================== - -GCC usually addresses every static object as a separate entity. For -example, if we have: - - static int a, b, c; - int foo (void) { return a + b + c; } - - the code for 'foo' will usually calculate three separate symbolic -addresses: those of 'a', 'b' and '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: - - int foo (void) - { - register int *xr = &x; - return xr[&a - &x] + xr[&b - &x] + xr[&c - &x]; - } - - (which isn't valid C). We refer to shared addresses like 'x' as -"section anchors". Their use is controlled by '-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 'TARGET_MIN_ANCHOR_OFFSET' or -'TARGET_MAX_ANCHOR_OFFSET' is set to a nonzero value. - - -- 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. - - -- Target Hook: HOST_WIDE_INT TARGET_MAX_ANCHOR_OFFSET - Like 'TARGET_MIN_ANCHOR_OFFSET', but the maximum (inclusive) offset - that should be applied to section anchors. The default value is 0. - - -- Target Hook: void TARGET_ASM_OUTPUT_ANCHOR (rtx X) - Write the assembly code to define section anchor X, which is a - 'SYMBOL_REF' for which 'SYMBOL_REF_ANCHOR_P (X)' is true. The hook - is called with the assembly output position set to the beginning of - 'SYMBOL_REF_BLOCK (X)'. - - If 'ASM_OUTPUT_DEF' is available, the hook's default definition - uses it to define the symbol as '. + SYMBOL_REF_BLOCK_OFFSET (X)'. - If 'ASM_OUTPUT_DEF' is not available, the hook's default definition - is 'NULL', which disables the use of section anchors altogether. - - -- Target Hook: bool TARGET_USE_ANCHORS_FOR_SYMBOL_P (const_rtx X) - Return true if GCC should attempt to use anchors to access - 'SYMBOL_REF' X. You can assume 'SYMBOL_REF_HAS_BLOCK_INFO_P (X)' - and '!SYMBOL_REF_ANCHOR_P (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. - - -File: gccint.info, Node: Condition Code, Next: Costs, Prev: Anchored Addresses, Up: Target Macros - -17.16 Condition Code Status -=========================== - -The macros in this section can be split in two families, according to -the two ways of representing condition codes in GCC. - - The first representation is the so called '(cc0)' representation (*note -Jump Patterns::), where all instructions can have an implicit clobber of -the condition codes. The second is the condition code register -representation, which provides better schedulability for architectures -that do have a condition code register, but on which most instructions -do not affect it. The latter category includes most RISC machines. - - The implicit clobbering poses a strong restriction on the placement of -the definition and use of the condition code. In the past the -definition and use were always adjacent. However, recent changes to -support trapping arithmatic may result in the definition and user being -in different blocks. Thus, there may be a 'NOTE_INSN_BASIC_BLOCK' -between them. Additionally, the definition may be the source of -exception handling edges. - - These restrictions can prevent important optimizations on some -machines. 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. - - For this reason, it is possible and suggested to use a register to -represent the condition code for new ports. 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. Registers used to store the condition code value will usually -have a mode that is in class 'MODE_CC'. - - Alternatively, you can use 'BImode' if the comparison operator is -specified already in the compare instruction. In this case, you are not -interested in most macros in this section. - -* Menu: - -* CC0 Condition Codes:: Old style representation of condition codes. -* MODE_CC Condition Codes:: Modern representation of condition codes. - - -File: gccint.info, Node: CC0 Condition Codes, Next: MODE_CC Condition Codes, Up: Condition Code - -17.16.1 Representation of condition codes using '(cc0)' -------------------------------------------------------- - -The file 'conditions.h' defines a variable '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 'CC_STATUS_MDEP'. - - -- Macro: CC_STATUS_MDEP - C code for a data type which is used for declaring the 'mdep' - component of 'cc_status'. It defaults to 'int'. - - This macro is not used on machines that do not use 'cc0'. - - -- Macro: CC_STATUS_MDEP_INIT - A C expression to initialize the '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 'cc0'. - - -- Macro: NOTICE_UPDATE_CC (EXP, INSN) - A C compound statement to set the components of 'cc_status' - appropriately for an insn INSN whose body is 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 '(cc0)'. - - This macro is not used on machines that do not use '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 - 'NOTICE_UPDATE_CC' can leave 'cc_status' unaltered for such insns. - But suppose that the previous insn set the condition code based on - location 'a4@(102)' and the current insn stores a new value in - 'a4'. Although the condition code is not changed by this, it will - no longer be true that it reflects the contents of 'a4@(102)'. - Therefore, 'NOTICE_UPDATE_CC' must alter 'cc_status' in this case - to say that nothing is known about the condition code value. - - The definition of 'NOTICE_UPDATE_CC' must be prepared to deal with - the results of peephole optimization: insns whose patterns are - 'parallel' RTXs containing various 'reg', '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 - 'NOTICE_UPDATE_CC' should do when it sees one is just to run - 'CC_STATUS_INIT'. - - A possible definition of 'NOTICE_UPDATE_CC' is to call a function - that looks at an attribute (*note Insn Attributes::) named, for - example, 'cc'. This avoids having detailed information about - patterns in two places, the 'md' file and in 'NOTICE_UPDATE_CC'. - - -File: gccint.info, Node: MODE_CC Condition Codes, Prev: CC0 Condition Codes, Up: Condition Code - -17.16.2 Representation of condition codes using registers ---------------------------------------------------------- - - -- Macro: SELECT_CC_MODE (OP, X, Y) - On many machines, the condition code may be produced by other - instructions than compares, for example the branch can use directly - the condition code set by a subtract instruction. However, on some - machines when the condition code is set this way some bits (such as - the overflow bit) are not set in the same way as a test - instruction, so that a different branch instruction must be used - for some conditional branches. When this happens, use the machine - mode of the condition code register to record different formats of - the condition code register. Modes can also be used to record - which compare instruction (e.g. a signed or an unsigned - comparison) produced the condition codes. - - If other modes than 'CCmode' are required, add them to - 'MACHINE-modes.def' and define 'SELECT_CC_MODE' to choose a mode - given an operand of a compare. This is needed because the modes - have to be chosen not only during RTL generation but also, for - example, by instruction combination. The result of - 'SELECT_CC_MODE' should be consistent with the mode used in the - patterns; for example to support the case of the add on the SPARC - discussed above, we have the pattern - - (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)))] - "" - "...") - - together with a 'SELECT_CC_MODE' that returns 'CC_NOOVmode' for - comparisons whose argument is a 'plus': - - #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)) - - Another reason to use modes is to retain information on which - operands were used by the comparison; see 'REVERSIBLE_CC_MODE' - later in this section. - - You should define this macro if and only if you define extra CC - modes in 'MACHINE-modes.def'. - - -- Target Hook: void TARGET_CANONICALIZE_COMPARISON (int *CODE, rtx - *OP0, rtx *OP1, bool OP0_PRESERVE_VALUE) - 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 'GT' comparison, but you can use an 'LT' - comparison instead and swap the order of the operands. - - On such machines, implement this hook to do any required - conversions. CODE is the initial comparison code and OP0 and OP1 - are the left and right operands of the comparison, respectively. - If OP0_PRESERVE_VALUE is 'true' the implementation is not allowed - to change the value of OP0 since the value might be used in RTXs - which aren't comparisons. E.g. the implementation is not allowed - to swap operands in that case. - - 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 'md' file. - - You need not to implement this hook if it would never change the - comparison code or operands. - - -- Macro: REVERSIBLE_CC_MODE (MODE) - A C expression whose value is one if it is always safe to reverse a - comparison whose mode is MODE. If 'SELECT_CC_MODE' can ever return - MODE for a floating-point inequality comparison, then - 'REVERSIBLE_CC_MODE (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 - 'IEEE_FLOAT_FORMAT'. For example, here is the definition used on - the SPARC, where floating-point inequality comparisons are always - given 'CCFPEmode': - - #define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode) - - -- Macro: REVERSE_CONDITION (CODE, MODE) - A C expression whose value is reversed condition code of the CODE - for comparison done in CC_MODE MODE. The macro is used only in - case 'REVERSIBLE_CC_MODE (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: - - #define REVERSE_CONDITION(CODE, MODE) \ - ((MODE) != CCFPmode ? reverse_condition (CODE) \ - : reverse_condition_maybe_unordered (CODE)) - - -- Target Hook: bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int - *P1, unsigned int *P2) - On targets which do not use '(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 P2 should be set to - 'INVALID_REGNUM'. - - The default version of this hook returns false. - - -- Target Hook: enum machine_mode TARGET_CC_MODES_COMPATIBLE (enum - machine_mode M1, enum machine_mode M2) - On targets which use multiple condition code modes in class - '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 '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 'VOIDmode'. - - -File: gccint.info, Node: Costs, Next: Scheduling, Prev: Condition Code, Up: Target Macros - -17.17 Describing Relative Costs of Operations -============================================= - -These macros let you describe the relative speed of various operations -on the target machine. - - -- Macro: REGISTER_MOVE_COST (MODE, FROM, TO) - A C expression for the cost of moving data of mode MODE from a - register in class FROM to one in class TO. The classes are - expressed using the enumeration values such as '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 FROM is the - same as 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 'set' between two - hard registers, and if '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 'movM' pattern's constraints do not allow - such copying. - - These macros are obsolete, new ports should use the target hook - 'TARGET_REGISTER_MOVE_COST' instead. - - -- Target Hook: int TARGET_REGISTER_MOVE_COST (enum machine_mode MODE, - reg_class_t FROM, reg_class_t TO) - This target hook should return the cost of moving data of mode MODE - from a register in class FROM to one in class TO. The classes are - expressed using the enumeration values such as '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 FROM is the - same as 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 'set' between two - hard registers, and if 'TARGET_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 'movM' pattern's constraints do not allow - such copying. - - The default version of this function returns 2. - - -- Macro: MEMORY_MOVE_COST (MODE, CLASS, IN) - A C expression for the cost of moving data of mode MODE between a - register of class CLASS and memory; 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 '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 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 '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. - - These macros are obsolete, new ports should use the target hook - 'TARGET_MEMORY_MOVE_COST' instead. - - -- Target Hook: int TARGET_MEMORY_MOVE_COST (enum machine_mode MODE, - reg_class_t RCLASS, bool IN) - This target hook should return the cost of moving data of mode MODE - between a register of class RCLASS and memory; IN is 'false' if the - value is to be written to memory, 'true' if it is to be read in. - This cost is relative to those in 'TARGET_REGISTER_MOVE_COST'. If - moving between registers and memory is more expensive than between - two registers, you should add this target hook to express the - relative cost. - - If you do not add this target hook, 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 RCLASS but the reload - mechanism is more complex than copying via an intermediate, use - this target hook to reflect the actual cost of the move. - - GCC defines the function '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, use this target hook to - add some other value to the result of that function. The arguments - to that function are the same as to this target hook. - - -- Macro: BRANCH_COST (SPEED_P, PREDICTABLE_P) - A C expression for the cost of a branch instruction. A value of 1 - is the default; other values are interpreted relative to that. - Parameter SPEED_P is true when the branch in question should be - optimized for speed. When it is false, 'BRANCH_COST' should return - a value optimal for code size rather than performance. - PREDICTABLE_P is true for well-predicted branches. On many - architectures the 'BRANCH_COST' can be reduced then. - - Here are additional macros which do not specify precise relative costs, -but only that certain actions are more expensive than GCC would -ordinarily expect. - - -- Macro: SLOW_BYTE_ACCESS - Define this macro as a C expression which is nonzero if accessing - less than a word of memory (i.e. a 'char' or a '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. - - -- Macro: SLOW_UNALIGNED_ACCESS (MODE, ALIGNMENT) - Define this macro to be the value 1 if memory accesses described by - the MODE and 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 - '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 - 'STRICT_ALIGNMENT' is nonzero. - - -- Macro: MOVE_RATIO (SPEED) - The threshold of number of scalar memory-to-memory move insns, - _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 - 'define_expand' that emits a sequence of insns, this macro counts - the number of such sequences. - - The parameter SPEED is true if the code is currently being - optimized for speed rather than size. - - If you don't define this, a reasonable default is used. - - -- Macro: MOVE_BY_PIECES_P (SIZE, ALIGNMENT) - A C expression used to determine whether '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 'move_by_pieces_ninsns' - returns less than 'MOVE_RATIO'. - - -- Macro: MOVE_MAX_PIECES - A C expression used by 'move_by_pieces' to determine the largest - unit a load or store used to copy memory is. Defaults to - 'MOVE_MAX'. - - -- Macro: CLEAR_RATIO (SPEED) - The threshold of number of scalar move insns, _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. - - The parameter SPEED is true if the code is currently being - optimized for speed rather than size. - - If you don't define this, a reasonable default is used. - - -- Macro: CLEAR_BY_PIECES_P (SIZE, ALIGNMENT) - A C expression used to determine whether '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 'move_by_pieces_ninsns' - returns less than 'CLEAR_RATIO'. - - -- Macro: SET_RATIO (SPEED) - The threshold of number of scalar move insns, _below_ which a - sequence of insns should be generated to set memory to a constant - value, instead of a block set insn or a library call. Increasing - the value will always make code faster, but eventually incurs high - cost in increased code size. - - The parameter SPEED is true if the code is currently being - optimized for speed rather than size. - - If you don't define this, it defaults to the value of 'MOVE_RATIO'. - - -- Macro: SET_BY_PIECES_P (SIZE, ALIGNMENT) - A C expression used to determine whether '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 '__builtin_memset' when - storing values other than constant zero. Defaults to 1 if - 'move_by_pieces_ninsns' returns less than 'SET_RATIO'. - - -- Macro: STORE_BY_PIECES_P (SIZE, ALIGNMENT) - A C expression used to determine whether 'store_by_pieces' will be - used to set a chunk of memory to a constant string value, or - whether some other mechanism will be used. Used by - '__builtin_strcpy' when called with a constant source string. - Defaults to 1 if 'move_by_pieces_ninsns' returns less than - 'MOVE_RATIO'. - - -- Macro: USE_LOAD_POST_INCREMENT (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 - 'HAVE_POST_INCREMENT'. - - -- Macro: USE_LOAD_POST_DECREMENT (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 - 'HAVE_POST_DECREMENT'. - - -- Macro: USE_LOAD_PRE_INCREMENT (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 - 'HAVE_PRE_INCREMENT'. - - -- Macro: USE_LOAD_PRE_DECREMENT (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 - 'HAVE_PRE_DECREMENT'. - - -- Macro: USE_STORE_POST_INCREMENT (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 - 'HAVE_POST_INCREMENT'. - - -- Macro: USE_STORE_POST_DECREMENT (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 - 'HAVE_POST_DECREMENT'. - - -- Macro: USE_STORE_PRE_INCREMENT (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 - 'HAVE_PRE_INCREMENT'. - - -- Macro: USE_STORE_PRE_DECREMENT (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 - 'HAVE_PRE_DECREMENT'. - - -- Macro: 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. - - -- Macro: LOGICAL_OP_NON_SHORT_CIRCUIT - Define this macro if a non-short-circuit operation produced by - 'fold_range_test ()' is optimal. This macro defaults to true if - 'BRANCH_COST' is greater than or equal to the value 2. - - -- Target Hook: bool TARGET_RTX_COSTS (rtx X, int CODE, int OUTER_CODE, - int OPNO, int *TOTAL, bool SPEED) - 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 X, and the fact that X appears as - operand OPNO of an expression with rtx code OUTER_CODE. That is, - the hook can assume that there is some rtx Y such that 'GET_CODE - (Y) == OUTER_CODE' and such that either (a) 'XEXP (Y, OPNO) == X' - or (b) 'XVEC (Y, OPNO)' contains X. - - CODE is X's expression code--redundant, since it can be obtained - with 'GET_CODE (X)'. - - In implementing this hook, you can use the construct 'COSTS_N_INSNS - (N)' to specify a cost equal to N fast instructions. - - On entry to the hook, '*TOTAL' contains a default estimate for the - cost of the expression. The hook should modify this value as - necessary. Traditionally, the default costs are 'COSTS_N_INSNS - (5)' for multiplications, 'COSTS_N_INSNS (7)' for division and - modulus operations, and 'COSTS_N_INSNS (1)' for all other - operations. - - When optimizing for code size, i.e. when 'speed' is false, this - target hook should be used to estimate the relative size cost of an - expression, again relative to 'COSTS_N_INSNS'. - - The hook returns true when all subexpressions of X have been - processed, and false when 'rtx_cost' should recurse. - - -- Target Hook: int TARGET_ADDRESS_COST (rtx ADDRESS, enum machine_mode - MODE, addr_space_t AS, bool SPEED) - This hook computes the cost of an addressing mode that contains - ADDRESS. If not defined, the cost is computed from the ADDRESS - expression and the '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 '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 '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. - - -File: gccint.info, Node: Scheduling, Next: Sections, Prev: Costs, Up: Target Macros - -17.18 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. - - -- 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 'TARGET_SCHED_REORDER' and - '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 'TARGET_SCHED_VARIABLE_ISSUE'. - - -- Target Hook: int TARGET_SCHED_VARIABLE_ISSUE (FILE *FILE, int - VERBOSE, rtx INSN, int 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 - 'MORE - 1' for insns other than 'CLOBBER' and '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. FILE is either a - null pointer, or a stdio stream to write any debug output to. - VERBOSE is the verbose level provided by '-fsched-verbose-N'. INSN - is the instruction that was scheduled. - - -- Target Hook: int TARGET_SCHED_ADJUST_COST (rtx INSN, rtx LINK, rtx - DEP_INSN, int COST) - This function corrects the value of COST based on the relationship - between INSN and DEP_INSN through the dependence LINK. It should - return the new value. The default is to make no adjustment to - 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 - *note Processor pipeline description::. - - -- Target Hook: int TARGET_SCHED_ADJUST_PRIORITY (rtx INSN, int - PRIORITY) - This hook adjusts the integer scheduling priority PRIORITY of INSN. - It should return the new priority. Increase the priority to - execute INSN earlier, reduce the priority to execute INSN later. - Do not define this hook if you do not need to adjust the scheduling - priorities of insns. - - -- Target Hook: int TARGET_SCHED_REORDER (FILE *FILE, int VERBOSE, rtx - *READY, int *N_READYP, int 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 'VLIW' - machines). FILE is either a null pointer, or a stdio stream to - write any debug output to. VERBOSE is the verbose level provided - by '-fsched-verbose-N'. READY is a pointer to the ready list of - instructions that are ready to be scheduled. 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 READY[*N_READYP - 1] - and going to READY[0]. 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 'issue_rate'. See also - 'TARGET_SCHED_REORDER2'. - - -- Target Hook: int TARGET_SCHED_REORDER2 (FILE *FILE, int VERBOSE, rtx - *READY, int *N_READYP, int CLOCK) - Like '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 - '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. - - -- Target Hook: bool TARGET_SCHED_MACRO_FUSION_P (void) - This hook is used to check whether target platform supports macro - fusion. - - -- Target Hook: bool TARGET_SCHED_MACRO_FUSION_PAIR_P (rtx CONDGEN, rtx - CONDJMP) - This hook is used to check whether two insns could be macro fused - for target microarchitecture. If this hook returns true for the - given insn pair (CONDGEN and CONDJMP), scheduler will put them into - a sched group, and they will not be scheduled apart. - - -- Target Hook: void TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK (rtx - HEAD, rtx TAIL) - This hook is called after evaluation forward dependencies of insns - in chain given by two parameter values (HEAD and 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. - - -- Target Hook: void TARGET_SCHED_INIT (FILE *FILE, int VERBOSE, int - MAX_READY) - This hook is executed by the scheduler at the beginning of each - block of instructions that are to be scheduled. FILE is either a - null pointer, or a stdio stream to write any debug output to. - VERBOSE is the verbose level provided by '-fsched-verbose-N'. - 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 - 'TARGET_SCHED_REORDER'. - - -- Target Hook: void TARGET_SCHED_FINISH (FILE *FILE, int 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. FILE is - either a null pointer, or a stdio stream to write any debug output - to. VERBOSE is the verbose level provided by '-fsched-verbose-N'. - - -- Target Hook: void TARGET_SCHED_INIT_GLOBAL (FILE *FILE, int VERBOSE, - int OLD_MAX_UID) - This hook is executed by the scheduler after function level - initializations. FILE is either a null pointer, or a stdio stream - to write any debug output to. VERBOSE is the verbose level - provided by '-fsched-verbose-N'. OLD_MAX_UID is the maximum insn - uid when scheduling begins. - - -- Target Hook: void TARGET_SCHED_FINISH_GLOBAL (FILE *FILE, int - VERBOSE) - This is the cleanup hook corresponding to - 'TARGET_SCHED_INIT_GLOBAL'. FILE is either a null pointer, or a - stdio stream to write any debug output to. VERBOSE is the verbose - level provided by '-fsched-verbose-N'. - - -- Target Hook: rtx 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 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. - - -- Target Hook: void TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN (void) - The hook can be used to initialize data used by the previous hook. - - -- Target Hook: rtx TARGET_SCHED_DFA_POST_CYCLE_INSN (void) - The hook is analogous to '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. - - -- Target Hook: void TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN (void) - The hook is analogous to 'TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN' but - used to initialize data used by the previous hook. - - -- Target Hook: void TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE (void) - The hook to notify target that the current simulated cycle is about - to finish. The hook is analogous to - 'TARGET_SCHED_DFA_PRE_CYCLE_INSN' but used to change the state in - more complicated situations - e.g., when advancing state on a - single insn is not enough. - - -- Target Hook: void TARGET_SCHED_DFA_POST_ADVANCE_CYCLE (void) - The hook to notify target that new simulated cycle has just - started. The hook is analogous to - 'TARGET_SCHED_DFA_POST_CYCLE_INSN' but used to change the state in - more complicated situations - e.g., when advancing state on a - single insn is not enough. - - -- 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 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 '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 VLIW processor, - the code could actually solve the problem of packing simple insns - into the VLIW insn. Of course, if the rules of VLIW packing are - described in the automaton. - - This code also could be used for superscalar RISC processors. Let - us consider a superscalar RISC processor with 3 pipelines. Some - insns can be executed in pipelines A or B, some insns can be - executed only in pipelines B or C, and one insn can be executed in - pipeline B. The processor may issue the 1st insn into A and the - 2nd one into B. In this case, the 3rd insn will wait for freeing 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. - - -- Target Hook: int - TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD (rtx - INSN) - - 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, the insn will be not chosen to be issued. - - The default is that any ready insns can be chosen to be issued. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN (void - *DATA, char *READY_TRY, int N_READY, bool FIRST_CYCLE_INSN_P) - This hook prepares the target backend for a new round of multipass - scheduling. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE (void - *DATA, char *READY_TRY, int N_READY, rtx INSN, const void - *PREV_DATA) - This hook is called when multipass scheduling evaluates instruction - INSN. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK - (const void *DATA, char *READY_TRY, int N_READY) - This is called when multipass scheduling backtracks from evaluation - of an instruction. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END (const void - *DATA) - This hook notifies the target about the result of the concluded - current round of multipass scheduling. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT (void - *DATA) - This hook initializes target-specific data used in multipass - scheduling. - - -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI (void - *DATA) - This hook finalizes target-specific data used in multipass - scheduling. - - -- Target Hook: int TARGET_SCHED_DFA_NEW_CYCLE (FILE *DUMP, int - VERBOSE, rtx INSN, int LAST_CLOCK, int CLOCK, int *SORT_P) - This hook is called by the insn scheduler before issuing INSN on - cycle CLOCK. If the hook returns nonzero, INSN is not issued on - this processor cycle. Instead, the processor cycle is advanced. - If *SORT_P is zero, the insn ready queue is not sorted on the new - cycle start as usually. DUMP and VERBOSE specify the file and - verbosity level to use for debugging output. LAST_CLOCK and CLOCK - are, respectively, the processor cycle on which the previous insn - has been issued, and the current processor cycle. - - -- Target Hook: bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (struct _dep - *_DEP, int COST, int 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 first parameter - _DEP is the dependence being evaluated. The second parameter COST - is the cost of the dependence as estimated by the scheduler, and - the third parameter DISTANCE is the distance in cycles between the - two insns. The hook returns 'true' if considering the distance - between the two insns the dependence between them is considered - costly by the target, and '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. - - -- 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. - - -- Target Hook: void * TARGET_SCHED_ALLOC_SCHED_CONTEXT (void) - Return a pointer to a store large enough to hold target scheduling - context. - - -- Target Hook: void TARGET_SCHED_INIT_SCHED_CONTEXT (void *TC, bool - CLEAN_P) - Initialize store pointed to by TC to hold target scheduling - context. It CLEAN_P is true then initialize TC as if scheduler is - at the beginning of the block. Otherwise, copy the current context - into TC. - - -- Target Hook: void TARGET_SCHED_SET_SCHED_CONTEXT (void *TC) - Copy target scheduling context pointed to by TC to the current - context. - - -- Target Hook: void TARGET_SCHED_CLEAR_SCHED_CONTEXT (void *TC) - Deallocate internal data in target scheduling context pointed to by - TC. - - -- Target Hook: void TARGET_SCHED_FREE_SCHED_CONTEXT (void *TC) - Deallocate a store for target scheduling context pointed to by TC. - - -- Target Hook: int TARGET_SCHED_SPECULATE_INSN (rtx INSN, unsigned int - DEP_STATUS, rtx *NEW_PAT) - This hook is called by the insn scheduler when INSN has only - speculative dependencies and therefore can be scheduled - speculatively. The hook is used to check if the pattern of 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. - REQUEST describes the type of requested speculation. If the return - value equals 1 then NEW_PAT is assigned the generated speculative - pattern. - - -- Target Hook: bool TARGET_SCHED_NEEDS_BLOCK_P (unsigned int - DEP_STATUS) - This hook is called by the insn scheduler during generation of - recovery code for INSN. It should return 'true', if the - corresponding check instruction should branch to recovery code, or - 'false' otherwise. - - -- Target Hook: rtx TARGET_SCHED_GEN_SPEC_CHECK (rtx INSN, rtx LABEL, - unsigned int DS) - This hook is called by the insn scheduler to generate a pattern for - recovery check instruction. If MUTATE_P is zero, then INSN is a - speculative instruction for which the check should be generated. - 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 MUTATE_P is nonzero, - then a pattern for a branchy check corresponding to a simple check - denoted by INSN should be generated. In this case LABEL can't be - null. - - -- Target Hook: bool - TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC - (const_rtx INSN) - This hook is used as a workaround for - '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 instructions that stand first in the - ready list from being scheduled on the current cycle. If the hook - returns 'false', INSN will not be chosen to be issued. For - non-speculative instructions, the hook should always return 'true'. - For example, in the ia64 backend the hook is used to cancel data - speculative insns when the ALAT table is nearly full. - - -- Target Hook: void TARGET_SCHED_SET_SCHED_FLAGS (struct spec_info_def - *SPEC_INFO) - This hook is used by the insn scheduler to find out what features - should be enabled/used. The structure *SPEC_INFO should be filled - in by the target. The structure describes speculation types that - can be used in the scheduler. - - -- Target Hook: int TARGET_SCHED_SMS_RES_MII (struct ddg *G) - This hook is called by the swing modulo scheduler to calculate a - resource-based lower bound which is based on the resources - available in the machine and the resources required by each - instruction. The target backend can use G to calculate such bound. - A very simple lower bound will be used in case this hook is not - implemented: the total number of instructions divided by the issue - rate. - - -- Target Hook: bool TARGET_SCHED_DISPATCH (rtx INSN, int X) - This hook is called by Haifa Scheduler. It returns true if - dispatch scheduling is supported in hardware and the condition - specified in the parameter is true. - - -- Target Hook: void TARGET_SCHED_DISPATCH_DO (rtx INSN, int X) - This hook is called by Haifa Scheduler. It performs the operation - specified in its second parameter. - - -- Target Hook: bool TARGET_SCHED_EXPOSED_PIPELINE - True if the processor has an exposed pipeline, which means that not - just the order of instructions is important for correctness when - scheduling, but also the latencies of operations. - - -- Target Hook: int TARGET_SCHED_REASSOCIATION_WIDTH (unsigned int OPC, - enum machine_mode MODE) - This hook is called by tree reassociator to determine a level of - parallelism required in output calculations chain. - - -File: gccint.info, Node: Sections, Next: PIC, Prev: Scheduling, Up: Target Macros - -17.19 Dividing the Output into Sections (Texts, Data, ...) -========================================================== - -An object file is divided into sections containing different types of -data. In the most common case, there are three sections: the "text -section", which holds instructions and read-only data; the "data -section", which holds initialized writable data; and the "bss section", -which holds uninitialized data. Some systems have other kinds of -sections. - - 'varasm.c' provides several well-known sections, such as -'text_section', 'data_section' and 'bss_section'. The normal way of -controlling a 'FOO_section' variable is to define the associated -'FOO_SECTION_ASM_OP' macro, as described below. The macros are only -read once, when 'varasm.c' initializes itself, so their values must be -run-time constants. They may however depend on command-line flags. - - _Note:_ Some run-time files, such 'crtstuff.c', also make use of the -'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 'TARGET_ASM_INIT_SECTIONS' hook and use -'get_unnamed_section' to set up the sections. - - You must always create a 'text_section', either by defining -'TEXT_SECTION_ASM_OP' or by initializing 'text_section' in -'TARGET_ASM_INIT_SECTIONS'. The same is true of 'data_section' and -'DATA_SECTION_ASM_OP'. If you do not create a distinct -'readonly_data_section', the default is to reuse 'text_section'. - - All the other 'varasm.c' sections are optional, and are null if the -target does not provide them. - - -- Macro: 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 '"\t.text"' is right. - - -- Macro: 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. - - -- Macro: UNLIKELY_EXECUTED_TEXT_SECTION_NAME - If defined, a C string constant for the name of the section - containing unlikely executed functions in the program. - - -- Macro: 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 '"\t.data"' is right. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: 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 - 'ASM_OUTPUT_ALIGNED_BSS' not defined, uninitialized global data - will be output in the data section if '-fno-common' is passed, - otherwise 'ASM_OUTPUT_COMMON' will be used. - - -- Macro: 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. - - -- Macro: TLS_COMMON_ASM_OP - If defined, a C expression whose value is a string containing the - assembler operation to identify the following data as thread-local - common data. The default is '".tls_common"'. - - -- Macro: TLS_SECTION_ASM_FLAG - If defined, a C expression whose value is a character constant - containing the flag used to mark a section as a TLS section. The - default is ''T''. - - -- Macro: 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 'init_section' variable; it is used entirely in - runtime code. - - -- Macro: 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 'fini_section' variable; it is used entirely in - runtime code. - - -- Macro: 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 '.init_array' (or equivalent) - section. If not defined, GCC will assume such a section does not - exist. Do not define both this macro and 'INIT_SECTION_ASM_OP'. - - -- Macro: 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 '.fini_array' (or equivalent) - section. If not defined, GCC will assume such a section does not - exist. Do not define both this macro and 'FINI_SECTION_ASM_OP'. - - -- Macro: CRT_CALL_STATIC_FUNCTION (SECTION_OP, FUNCTION) - If defined, an ASM statement that switches to a different section - via SECTION_OP, calls FUNCTION, and switches back to the text - section. This is used in 'crtstuff.c' if 'INIT_SECTION_ASM_OP' or - '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. - - -- Macro: 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 '.sdata' - section (like MIPS), you could compile crtstuff with '-G 0' so that - it doesn't require small data support from your application, but - use this macro to put small data into '.sdata' so that your - application can access these variables whether it uses small data - or not. - - -- Macro: 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 - '.init' and '.fini' sections to have to same alignment and thus - prevent the linker from having to add any padding. - - -- Macro: JUMP_TABLES_IN_TEXT_SECTION - Define this macro to be an expression with a nonzero value if jump - tables (for '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. - - -- Target Hook: void TARGET_ASM_INIT_SECTIONS (void) - Define this hook if you need to do something special to set up the - '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. - - -- Target Hook: int 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 '-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. - - -- Target Hook: section * TARGET_ASM_SELECT_SECTION (tree EXP, int - RELOC, unsigned HOST_WIDE_INT ALIGN) - Return the section into which EXP should be placed. You can assume - that EXP is either a 'VAR_DECL' node or a constant of some sort. - RELOC indicates whether the initial value of EXP requires link-time - relocations. Bit 0 is set when variable contains local relocations - only, while bit 1 is set for global relocations. ALIGN is the - constant alignment in bits. - - The default version of this function takes care of putting - read-only variables in 'readonly_data_section'. - - See also USE_SELECT_SECTION_FOR_FUNCTIONS. - - -- Macro: USE_SELECT_SECTION_FOR_FUNCTIONS - Define this macro if you wish TARGET_ASM_SELECT_SECTION to be - called for 'FUNCTION_DECL's as well as for variables and constants. - - In the case of a 'FUNCTION_DECL', 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. - - -- Target Hook: void TARGET_ASM_UNIQUE_SECTION (tree DECL, int RELOC) - Build up a unique section name, expressed as a 'STRING_CST' node, - and assign it to 'DECL_SECTION_NAME (DECL)'. As with - 'TARGET_ASM_SELECT_SECTION', RELOC indicates whether the initial - value of 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 'foo' would be placed in '.text.foo'. - Whatever the actual target object format, this is often good - enough. - - -- Target Hook: section * TARGET_ASM_FUNCTION_RODATA_SECTION (tree - DECL) - Return the readonly data section associated with 'DECL_SECTION_NAME - (DECL)'. The default version of this function selects - '.gnu.linkonce.r.name' if the function's section is - '.gnu.linkonce.t.name', '.rodata.name' if function is in - '.text.name', and the normal readonly-data section otherwise. - - -- Target Hook: const char * TARGET_ASM_MERGEABLE_RODATA_PREFIX - Usually, the compiler uses the prefix '".rodata"' to construct - section names for mergeable constant data. Define this macro to - override the string if a different section name should be used. - - -- Target Hook: section * TARGET_ASM_TM_CLONE_TABLE_SECTION (void) - Return the section that should be used for transactional memory - clone tables. - - -- Target Hook: section * TARGET_ASM_SELECT_RTX_SECTION (enum - machine_mode MODE, rtx X, unsigned HOST_WIDE_INT ALIGN) - Return the section into which a constant X, of mode MODE, should be - placed. You can assume that X is some kind of constant in RTL. - The argument MODE is redundant except in the case of a 'const_int' - rtx. ALIGN is the constant alignment in bits. - - The default version of this function takes care of putting symbolic - constants in 'flag_pic' mode in 'data_section' and everything else - in 'readonly_data_section'. - - -- Target Hook: tree TARGET_MANGLE_DECL_ASSEMBLER_NAME (tree DECL, tree - ID) - Define this hook if you need to postprocess the assembler name - generated by target-independent code. The ID provided to this hook - will be the computed name (e.g., the macro 'DECL_NAME' of the DECL - in C, or the mangled name of the DECL in C++). The return value of - the hook is an 'IDENTIFIER_NODE' for the appropriate mangled name - on your target system. The default implementation of this hook - just returns the ID provided. - - -- Target Hook: void TARGET_ENCODE_SECTION_INFO (tree DECL, rtx RTL, - int 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 - DECL, which may be a variable or function declaration or an entry - in the constant pool. In either case, RTL is the rtl in question. - Do _not_ use 'DECL_RTL (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 - 'mem' whose address is a 'symbol_ref'. Most decls will also have - this form, but that is not guaranteed. Global register variables, - for instance, will have a 'reg' for their rtl. (Normally the right - thing to do with such unusual rtl is leave it alone.) - - The NEW_DECL_P argument will be true if this is the first time that - '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 - 'DECL_ATTRIBUTES'. NEW_DECL_P is always true when the hook is - called for a constant. - - The usual thing for this hook to do is to record flags in the - 'symbol_ref', using 'SYMBOL_REF_FLAG' or '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 'SYMBOL_REF_FLAGS'. - - The default definition of this hook, 'default_encode_section_info' - in 'varasm.c', sets a number of commonly-useful bits in - 'SYMBOL_REF_FLAGS'. Check whether the default does what you need - before overriding it. - - -- Target Hook: const char * TARGET_STRIP_NAME_ENCODING (const char - *NAME) - Decode NAME and return the real name part, sans the characters that - 'TARGET_ENCODE_SECTION_INFO' may have added. - - -- Target Hook: bool TARGET_IN_SMALL_DATA_P (const_tree EXP) - Returns true if EXP should be placed into a "small data" section. - The default version of this hook always returns false. - - -- 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. - - -- Target Hook: bool TARGET_PROFILE_BEFORE_PROLOGUE (void) - It returns true if target wants profile code emitted before - prologue. - - The default version of this hook use the target macro - 'PROFILE_BEFORE_PROLOGUE'. - - -- Target Hook: bool TARGET_BINDS_LOCAL_P (const_tree EXP) - Returns true if 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. - - -- Target Hook: bool TARGET_HAVE_TLS - Contains the value true if the target supports thread-local - storage. The default value is false. - - -File: gccint.info, Node: PIC, Next: Assembler Format, Prev: Sections, Up: Target Macros - -17.20 Position Independent Code -=============================== - -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 hook -'TARGET_LEGITIMATE_ADDRESS_P' and to the macro 'PRINT_OPERAND_ADDRESS', -as well as 'LEGITIMIZE_ADDRESS'. You must modify the definition of -'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. - - -- Macro: 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 'flag_pic' is true). - - -- Macro: PIC_OFFSET_TABLE_REG_CALL_CLOBBERED - A C expression that is nonzero if the register defined by - 'PIC_OFFSET_TABLE_REGNUM' is clobbered by calls. If not defined, - the default is zero. Do not define this macro if - 'PIC_OFFSET_TABLE_REGNUM' is not defined. - - -- Macro: LEGITIMATE_PIC_OPERAND_P (X) - A C expression that is nonzero if X is a legitimate immediate - operand on the target machine when generating position independent - code. You can assume that X satisfies 'CONSTANT_P', so you need - not check this. You can also assume FLAG_PIC is true, so you need - not check it either. You need not define this macro if all - constants (including 'SYMBOL_REF') can be immediate operands when - generating position independent code. - - -File: gccint.info, Node: Assembler Format, Next: Debugging Info, Prev: PIC, Up: Target Macros - -17.21 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. - - -File: gccint.info, Node: File Framework, Next: Data Output, Up: Assembler Format - -17.21.1 The Overall Framework of an Assembler File --------------------------------------------------- - -This describes the overall framework of an assembly file. - - -- Target Hook: void TARGET_ASM_FILE_START (void) - Output to '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 'default_file_start' at some point in your target hook. This - lets other target files rely on these variables. - - -- Target Hook: bool TARGET_ASM_FILE_START_APP_OFF - If this flag is true, the text of the macro 'ASM_APP_OFF' will be - printed as the very first line in the assembly file, unless - '-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 '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. - - -- Target Hook: bool TARGET_ASM_FILE_START_FILE_DIRECTIVE - If this flag is true, 'output_file_directive' will be called for - the primary source file, immediately after printing 'ASM_APP_OFF' - (if that is enabled). Most ELF assemblers expect this to be done. - The default is false. - - -- Target Hook: void TARGET_ASM_FILE_END (void) - Output to 'asm_out_file' any text which the assembler expects to - find at the end of a file. The default is to output nothing. - - -- Function: void file_end_indicate_exec_stack () - Some systems use a common convention, the '.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 'TARGET_ASM_FILE_END' to this function. If you need - to do other things in that hook, have your hook function call this - function. - - -- Target Hook: void TARGET_ASM_LTO_START (void) - Output to 'asm_out_file' any text which the assembler expects to - find at the start of an LTO section. The default is to output - nothing. - - -- Target Hook: void TARGET_ASM_LTO_END (void) - Output to 'asm_out_file' any text which the assembler expects to - find at the end of an LTO section. The default is to output - nothing. - - -- Target Hook: void TARGET_ASM_CODE_END (void) - Output to 'asm_out_file' any text which is needed before emitting - unwind info and debug info at the end of a file. Some targets emit - here PIC setup thunks that cannot be emitted at the end of file, - because they couldn't have unwind info then. The default is to - output nothing. - - -- Macro: 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. - - -- Macro: ASM_APP_ON - A C string constant for text to be output before each 'asm' - statement or group of consecutive ones. Normally this is '"#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. - - -- Macro: ASM_APP_OFF - A C string constant for text to be output after each 'asm' - statement or group of consecutive ones. Normally this is - '"#NO_APP"', which tells the GNU assembler to resume making the - time-saving assumptions that are valid for ordinary compiler - output. - - -- Macro: ASM_OUTPUT_SOURCE_FILENAME (STREAM, NAME) - A C statement to output COFF information or DWARF debugging - information which indicates that filename NAME is the current - source file to the stdio stream STREAM. - - This macro need not be defined if the standard form of output for - the file format in use is appropriate. - - -- Target Hook: void TARGET_ASM_OUTPUT_SOURCE_FILENAME (FILE *FILE, - const char *NAME) - Output COFF information or DWARF debugging information which - indicates that filename NAME is the current source file to the - stdio stream FILE. - - This target hook need not be defined if the standard form of output - for the file format in use is appropriate. - - -- Target Hook: void TARGET_ASM_OUTPUT_IDENT (const char *NAME) - Output a string based on NAME, suitable for the '#ident' directive, - or the equivalent directive or pragma in non-C-family languages. - If this hook is not defined, nothing is output for the '#ident' - directive. - - -- Macro: OUTPUT_QUOTED_STRING (STREAM, STRING) - A C statement to output the string STRING to the stdio stream - STREAM. If you do not call the function '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. - - -- Target Hook: void TARGET_ASM_NAMED_SECTION (const char *NAME, - unsigned int FLAGS, tree DECL) - Output assembly directives to switch to section NAME. The section - should have attributes as specified by FLAGS, which is a bit mask - of the 'SECTION_*' flags defined in 'output.h'. If DECL is - non-NULL, it is the 'VAR_DECL' or 'FUNCTION_DECL' with which this - section is associated. - - -- Target Hook: section * TARGET_ASM_FUNCTION_SECTION (tree DECL, enum - node_frequency FREQ, bool STARTUP, bool EXIT) - Return preferred text (sub)section for function DECL. Main purpose - of this function is to separate cold, normal and hot functions. - STARTUP is true when function is known to be used only at startup - (from static constructors or it is 'main()'). EXIT is true when - function is known to be used only at exit (from static - destructors). Return NULL if function should go to default text - section. - - -- Target Hook: void TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS (FILE - *FILE, tree DECL, bool NEW_IS_COLD) - Used by the target to emit any assembler directives or additional - labels needed when a function is partitioned between different - sections. Output should be written to FILE. The function decl is - available as DECL and the new section is 'cold' if NEW_IS_COLD is - 'true'. - - -- Common Target Hook: bool TARGET_HAVE_NAMED_SECTIONS - This flag is true if the target supports - 'TARGET_ASM_NAMED_SECTION'. It must not be modified by - command-line option processing. - - -- 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 'ASM_OUTPUT_SKIP' to allocate the space. - This is true on most ELF targets. - - -- Target Hook: unsigned int TARGET_SECTION_TYPE_FLAGS (tree DECL, - const char *NAME, int RELOC) - Choose a set of section attributes for use by - '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. 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 'flag_pic'. You should only need - to override this if your target has special flags that might be set - via '__attribute__'. - - -- Target Hook: int TARGET_ASM_RECORD_GCC_SWITCHES (print_switch_type - TYPE, const char *TEXT) - Provides the target with the ability to record the gcc command line - switches that have been passed to the compiler, and options that - are enabled. The TYPE argument specifies what is being recorded. - It can take the following values: - - 'SWITCH_TYPE_PASSED' - TEXT is a command line switch that has been set by the user. - - 'SWITCH_TYPE_ENABLED' - TEXT is an option which has been enabled. This might be as a - direct result of a command line switch, or because it is - enabled by default or because it has been enabled as a side - effect of a different command line switch. For example, the - '-O2' switch enables various different individual optimization - passes. - - 'SWITCH_TYPE_DESCRIPTIVE' - TEXT is either NULL or some descriptive text which should be - ignored. If TEXT is NULL then it is being used to warn the - target hook that either recording is starting or ending. The - first time TYPE is SWITCH_TYPE_DESCRIPTIVE and TEXT is NULL, - the warning is for start up and the second time the warning is - for wind down. This feature is to allow the target hook to - make any necessary preparations before it starts to record - switches and to perform any necessary tidying up after it has - finished recording switches. - - 'SWITCH_TYPE_LINE_START' - This option can be ignored by this target hook. - - 'SWITCH_TYPE_LINE_END' - This option can be ignored by this target hook. - - The hook's return value must be zero. Other return values may be - supported in the future. - - By default this hook is set to NULL, but an example implementation - is provided for ELF based targets. Called ELF_RECORD_GCC_SWITCHES, - it records the switches as ASCII text inside a new, string - mergeable section in the assembler output file. The name of the - new section is provided by the - 'TARGET_ASM_RECORD_GCC_SWITCHES_SECTION' target hook. - - -- Target Hook: const char * TARGET_ASM_RECORD_GCC_SWITCHES_SECTION - This is the name of the section that will be created by the example - ELF implementation of the 'TARGET_ASM_RECORD_GCC_SWITCHES' target - hook. - - -File: gccint.info, Node: Data Output, Next: Uninitialized Data, Prev: File Framework, Up: Assembler Format - -17.21.2 Output of Data ----------------------- - - -- Target Hook: const char * TARGET_ASM_BYTE_OP - -- Target Hook: const char * TARGET_ASM_ALIGNED_HI_OP - -- Target Hook: const char * TARGET_ASM_ALIGNED_SI_OP - -- Target Hook: const char * TARGET_ASM_ALIGNED_DI_OP - -- Target Hook: const char * TARGET_ASM_ALIGNED_TI_OP - -- Target Hook: const char * TARGET_ASM_UNALIGNED_HI_OP - -- Target Hook: const char * TARGET_ASM_UNALIGNED_SI_OP - -- Target Hook: const char * TARGET_ASM_UNALIGNED_DI_OP - -- Target Hook: const char * TARGET_ASM_UNALIGNED_TI_OP - These hooks specify assembly directives for creating certain kinds - of integer object. The 'TARGET_ASM_BYTE_OP' directive creates a - byte-sized object, the 'TARGET_ASM_ALIGNED_HI_OP' one creates an - aligned two-byte object, and so on. Any of the hooks may be - '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. - - -- Target Hook: bool TARGET_ASM_INTEGER (rtx X, unsigned int SIZE, int - ALIGNED_P) - The 'assemble_integer' function uses this hook to output an integer - object. X is the object's value, SIZE is its size in bytes and - ALIGNED_P indicates whether it is aligned. The function should - return 'true' if it was able to output the object. If it returns - false, 'assemble_integer' will try to split the object into smaller - parts. - - The default implementation of this hook will use the - 'TARGET_ASM_BYTE_OP' family of strings, returning 'false' when the - relevant string is 'NULL'. - - -- Target Hook: bool TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA (FILE *FILE, - rtx X) - A target hook to recognize RTX patterns that 'output_addr_const' - can't deal with, and output assembly code to FILE corresponding to - the pattern X. This may be used to allow machine-dependent - 'UNSPEC's to appear within constants. - - If target hook fails to recognize a pattern, it must return - 'false', so that a standard error message is printed. If it prints - an error message itself, by calling, for example, - 'output_operand_lossage', it may just return 'true'. - - -- Macro: ASM_OUTPUT_ASCII (STREAM, PTR, LEN) - A C statement to output to the stdio stream STREAM an assembler - instruction to assemble a string constant containing the LEN bytes - at PTR. PTR will be a C expression of type 'char *' and LEN a C - expression of type 'int'. - - If the assembler has a '.ascii' pseudo-op as found in the Berkeley - Unix assembler, do not define the macro 'ASM_OUTPUT_ASCII'. - - -- Macro: ASM_OUTPUT_FDESC (STREAM, DECL, N) - A C statement to output word N of a function descriptor for DECL. - This must be defined if 'TARGET_VTABLE_USES_DESCRIPTORS' is - defined, and is otherwise unused. - - -- Macro: 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. - - -- Macro: ASM_OUTPUT_POOL_PROLOGUE (FILE, FUNNAME, FUNDECL, SIZE) - A C statement to output assembler commands to define the start of - the constant pool for a function. FUNNAME is a string giving the - name of the function. Should the return type of the function be - required, it can be obtained via FUNDECL. 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. - - -- Macro: ASM_OUTPUT_SPECIAL_POOL_ENTRY (FILE, X, MODE, ALIGN, LABELNO, - 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 FILE is the standard I/O stream to output the - assembler code on. X is the RTL expression for the constant to - output, and MODE is the machine mode (in case X is a 'const_int'). - ALIGN is the required alignment for the value X; you should output - an assembler directive to force this much alignment. - - The argument 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: - - (*targetm.asm_out.internal_label) (FILE, "LC", LABELNO); - - When you output a pool entry specially, you should end with a - 'goto' to the label 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. - - -- Macro: ASM_OUTPUT_POOL_EPILOGUE (FILE FUNNAME FUNDECL SIZE) - A C statement to output assembler commands to at the end of the - constant pool for a function. FUNNAME is a string giving the name - of the function. Should the return type of the function be - required, you can obtain it via FUNDECL. 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. - - -- Macro: IS_ASM_LOGICAL_LINE_SEPARATOR (C, STR) - Define this macro as a C expression which is nonzero if C is used - as a logical line separator by the assembler. STR points to the - position in the string where C was found; this can be used if a - line separator uses multiple characters. - - If you do not define this macro, the default is that only the - character ';' is treated as a logical line separator. - - -- Target Hook: const char * TARGET_ASM_OPEN_PAREN - -- 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. - - These macros are provided by 'real.h' for writing the definitions of -'ASM_OUTPUT_DOUBLE' and the like: - - -- Macro: REAL_VALUE_TO_TARGET_SINGLE (X, L) - -- Macro: REAL_VALUE_TO_TARGET_DOUBLE (X, L) - -- Macro: REAL_VALUE_TO_TARGET_LONG_DOUBLE (X, L) - -- Macro: REAL_VALUE_TO_TARGET_DECIMAL32 (X, L) - -- Macro: REAL_VALUE_TO_TARGET_DECIMAL64 (X, L) - -- Macro: REAL_VALUE_TO_TARGET_DECIMAL128 (X, L) - These translate X, of type 'REAL_VALUE_TYPE', to the target's - floating point representation, and store its bit pattern in the - variable L. For 'REAL_VALUE_TO_TARGET_SINGLE' and - 'REAL_VALUE_TO_TARGET_DECIMAL32', this variable should be a simple - 'long int'. For the others, it should be an array of '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 'long int' array element. Each array element holds 32 bits of - the result, even if '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 'fprintf' in the order they should appear in the target - machine's memory. - - -File: gccint.info, Node: Uninitialized Data, Next: Label Output, Prev: Data Output, Up: Assembler Format - -17.21.3 Output of Uninitialized Variables ------------------------------------------ - -Each of the macros in this section is used to do the whole job of -outputting a single uninitialized variable. - - -- Macro: ASM_OUTPUT_COMMON (STREAM, NAME, SIZE, ROUNDED) - A C statement (sans semicolon) to output to the stdio stream STREAM - the assembler definition of a common-label named NAME whose size is - SIZE bytes. The variable ROUNDED is the size rounded up to - whatever alignment the caller wants. It is possible that SIZE may - be zero, for instance if a struct with no other member than a - zero-length array is defined. In this case, the backend must - output a symbol definition that allocates at least one byte, both - so that the address of the resulting object does not compare equal - to any other, and because some object formats cannot even express - the concept of a zero-sized common symbol, as that is how they - represent an ordinary undefined external. - - Use the expression 'assemble_name (STREAM, 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. - - -- Macro: ASM_OUTPUT_ALIGNED_COMMON (STREAM, NAME, SIZE, ALIGNMENT) - Like 'ASM_OUTPUT_COMMON' except takes the required alignment as a - separate, explicit argument. If you define this macro, it is used - in place of '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. - - -- Macro: ASM_OUTPUT_ALIGNED_DECL_COMMON (STREAM, DECL, NAME, SIZE, - ALIGNMENT) - Like 'ASM_OUTPUT_ALIGNED_COMMON' except that DECL of the variable - to be output, if there is one, or 'NULL_TREE' if there is no - corresponding variable. If you define this macro, GCC will use it - in place of both 'ASM_OUTPUT_COMMON' and - 'ASM_OUTPUT_ALIGNED_COMMON'. Define this macro when you need to - see the variable's decl in order to chose what to output. - - -- Macro: ASM_OUTPUT_ALIGNED_BSS (STREAM, DECL, NAME, SIZE, ALIGNMENT) - A C statement (sans semicolon) to output to the stdio stream STREAM - the assembler definition of uninitialized global DECL named NAME - whose size is SIZE bytes. The variable ALIGNMENT is the alignment - specified as the number of bits. - - Try to use function 'asm_output_aligned_bss' defined in file - 'varasm.c' when defining this macro. If unable, use the expression - 'assemble_name (STREAM, 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 this - macro. The other is to have 'TARGET_ASM_SELECT_SECTION' return a - switchable BSS section (*note - TARGET_HAVE_SWITCHABLE_BSS_SECTIONS::). You do not need to do - both. - - Some languages do not have '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. - - -- Macro: ASM_OUTPUT_LOCAL (STREAM, NAME, SIZE, ROUNDED) - A C statement (sans semicolon) to output to the stdio stream STREAM - the assembler definition of a local-common-label named NAME whose - size is SIZE bytes. The variable ROUNDED is the size rounded up to - whatever alignment the caller wants. - - Use the expression 'assemble_name (STREAM, 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. - - -- Macro: ASM_OUTPUT_ALIGNED_LOCAL (STREAM, NAME, SIZE, ALIGNMENT) - Like 'ASM_OUTPUT_LOCAL' except takes the required alignment as a - separate, explicit argument. If you define this macro, it is used - in place of '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. - - -- Macro: ASM_OUTPUT_ALIGNED_DECL_LOCAL (STREAM, DECL, NAME, SIZE, - ALIGNMENT) - Like 'ASM_OUTPUT_ALIGNED_DECL' except that DECL of the variable to - be output, if there is one, or 'NULL_TREE' if there is no - corresponding variable. If you define this macro, GCC will use it - in place of both 'ASM_OUTPUT_DECL' and 'ASM_OUTPUT_ALIGNED_DECL'. - Define this macro when you need to see the variable's decl in order - to chose what to output. - - -File: gccint.info, Node: Label Output, Next: Initialization, Prev: Uninitialized Data, Up: Assembler Format - -17.21.4 Output and Generation of Labels ---------------------------------------- - -This is about outputting labels. - - -- Macro: ASM_OUTPUT_LABEL (STREAM, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - the assembler definition of a label named NAME. Use the expression - 'assemble_name (STREAM, 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. - - -- Macro: ASM_OUTPUT_FUNCTION_LABEL (STREAM, NAME, DECL) - A C statement (sans semicolon) to output to the stdio stream STREAM - the assembler definition of a label named NAME of a function. Use - the expression 'assemble_name (STREAM, 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. - - If this macro is not defined, then the function name is defined in - the usual manner as a label (by means of 'ASM_OUTPUT_LABEL'). - - -- Macro: ASM_OUTPUT_INTERNAL_LABEL (STREAM, NAME) - Identical to 'ASM_OUTPUT_LABEL', except that NAME is known to refer - to a compiler-generated label. The default definition uses - 'assemble_name_raw', which is like 'assemble_name' except that it - is more efficient. - - -- Macro: 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 'config/elfos.h') is '"\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 'ASM_OUTPUT_SIZE_DIRECTIVE' and - '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. - - -- Macro: ASM_OUTPUT_SIZE_DIRECTIVE (STREAM, NAME, SIZE) - A C statement (sans semicolon) to output to the stdio stream STREAM - a directive telling the assembler that the size of the symbol NAME - is SIZE. SIZE is a 'HOST_WIDE_INT'. If you define 'SIZE_ASM_OP', - a default definition of this macro is provided. - - -- Macro: ASM_OUTPUT_MEASURED_SIZE (STREAM, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - a directive telling the assembler to calculate the size of the - symbol NAME by subtracting its address from the current address. - - If you define 'SIZE_ASM_OP', a default definition of this macro is - provided. The default assumes that the assembler recognizes a - special '.' symbol as referring to the current address, and can - calculate the difference between this and another symbol. If your - assembler does not recognize '.' or cannot do calculations with it, - you will need to redefine 'ASM_OUTPUT_MEASURED_SIZE' to use some - other technique. - - -- Macro: NO_DOLLAR_IN_LABEL - Define this macro if the assembler does not accept the character - '$' in label names. By default constructors and destructors in G++ - have '$' in the identifiers. If this macro is defined, '.' is used - instead. - - -- Macro: NO_DOT_IN_LABEL - Define this macro if the assembler does not accept the character - '.' in label names. By default constructors and destructors in G++ - have names that use '.'. If this macro is defined, these names are - rewritten to avoid '.'. - - -- Macro: 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 'config/elfos.h') is '"\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 '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. - - -- Macro: TYPE_OPERAND_FMT - A C string which specifies (using 'printf' syntax) the format of - the second operand to 'TYPE_ASM_OP'. On systems that use ELF, the - default (in 'config/elfos.h') is '"@%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 '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. - - -- Macro: ASM_OUTPUT_TYPE_DIRECTIVE (STREAM, TYPE) - A C statement (sans semicolon) to output to the stdio stream STREAM - a directive telling the assembler that the type of the symbol NAME - is TYPE. TYPE is a C string; currently, that string is always - either '"function"' or '"object"', but you should not count on - this. - - If you define 'TYPE_ASM_OP' and 'TYPE_OPERAND_FMT', a default - definition of this macro is provided. - - -- Macro: ASM_DECLARE_FUNCTION_NAME (STREAM, NAME, DECL) - A C statement (sans semicolon) to output to the stdio stream STREAM - any text necessary for declaring the name NAME of a function which - is being defined. This macro is responsible for outputting the - label definition (perhaps using 'ASM_OUTPUT_FUNCTION_LABEL'). The - argument DECL is the '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 - 'ASM_OUTPUT_FUNCTION_LABEL'). - - You may wish to use 'ASM_OUTPUT_TYPE_DIRECTIVE' in the definition - of this macro. - - -- Macro: ASM_DECLARE_FUNCTION_SIZE (STREAM, NAME, DECL) - A C statement (sans semicolon) to output to the stdio stream STREAM - any text necessary for declaring the size of a function which is - being defined. The argument NAME is the name of the function. The - argument DECL is the '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 'ASM_OUTPUT_MEASURED_SIZE' in the definition of - this macro. - - -- Macro: ASM_DECLARE_OBJECT_NAME (STREAM, NAME, DECL) - A C statement (sans semicolon) to output to the stdio stream STREAM - any text necessary for declaring the name NAME of an initialized - variable which is being defined. This macro must output the label - definition (perhaps using 'ASM_OUTPUT_LABEL'). The argument DECL - is the '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 'ASM_OUTPUT_LABEL'). - - You may wish to use 'ASM_OUTPUT_TYPE_DIRECTIVE' and/or - 'ASM_OUTPUT_SIZE_DIRECTIVE' in the definition of this macro. - - -- Target Hook: void TARGET_ASM_DECLARE_CONSTANT_NAME (FILE *FILE, - const char *NAME, const_tree EXPR, HOST_WIDE_INT SIZE) - A target hook to output to the stdio stream FILE any text necessary - for declaring the name NAME of a constant which is being defined. - This target hook is responsible for outputting the label definition - (perhaps using 'assemble_label'). The argument EXP is the value of - the constant, and SIZE is the size of the constant in bytes. The - NAME will be an internal label. - - The default version of this target hook, define the NAME in the - usual manner as a label (by means of 'assemble_label'). - - You may wish to use 'ASM_OUTPUT_TYPE_DIRECTIVE' in this target - hook. - - -- Macro: ASM_DECLARE_REGISTER_GLOBAL (STREAM, DECL, REGNO, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - any text necessary for claiming a register REGNO for a global - variable DECL with name NAME. - - If you don't define this macro, that is equivalent to defining it - to do nothing. - - -- Macro: ASM_FINISH_DECLARE_OBJECT (STREAM, DECL, TOPLEVEL, 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 'ASM_OUTPUT_SIZE_DIRECTIVE' and/or - 'ASM_OUTPUT_MEASURED_SIZE' in the definition of this macro. - - -- Target Hook: void TARGET_ASM_GLOBALIZE_LABEL (FILE *STREAM, const - char *NAME) - This target hook is a function to output to the stdio stream STREAM - some commands that will make the label NAME global; that is, - available for reference from other files. - - The default implementation relies on a proper definition of - 'GLOBAL_ASM_OP'. - - -- Target Hook: void TARGET_ASM_GLOBALIZE_DECL_NAME (FILE *STREAM, tree - DECL) - This target hook is a function to output to the stdio stream STREAM - some commands that will make the name associated with DECL global; - that is, available for reference from other files. - - The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL - target hook. - - -- Macro: ASM_WEAKEN_LABEL (STREAM, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - some commands that will make the label NAME weak; that is, - available for reference from other files but only used if no other - definition is available. Use the expression 'assemble_name - (STREAM, 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 'ASM_WEAKEN_DECL', GCC will not - support weak symbols and you should not define the 'SUPPORTS_WEAK' - macro. - - -- Macro: ASM_WEAKEN_DECL (STREAM, DECL, NAME, VALUE) - Combines (and replaces) the function of 'ASM_WEAKEN_LABEL' and - 'ASM_OUTPUT_WEAK_ALIAS', allowing access to the associated function - or variable decl. If VALUE is not 'NULL', this C statement should - output to the stdio stream STREAM assembler code which defines - (equates) the weak symbol NAME to have the value VALUE. If VALUE - is 'NULL', it should output commands to make NAME weak. - - -- Macro: ASM_OUTPUT_WEAKREF (STREAM, DECL, NAME, VALUE) - Outputs a directive that enables NAME to be used to refer to symbol - VALUE with weak-symbol semantics. 'decl' is the declaration of - 'name'. - - -- Macro: SUPPORTS_WEAK - A preprocessor constant expression which evaluates to true if the - target supports weak symbols. - - If you don't define this macro, 'defaults.h' provides a default - definition. If either 'ASM_WEAKEN_LABEL' or 'ASM_WEAKEN_DECL' is - defined, the default definition is '1'; otherwise, it is '0'. - - -- Macro: TARGET_SUPPORTS_WEAK - A C expression which evaluates to true if the target supports weak - symbols. - - If you don't define this macro, 'defaults.h' provides a default - definition. The default definition is '(SUPPORTS_WEAK)'. Define - this macro if you want to control weak symbol support with a - compiler flag such as '-melf'. - - -- Macro: MAKE_DECL_ONE_ONLY (DECL) - A C statement (sans semicolon) to mark 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 'COMDAT' - section flags in the Microsoft Windows PE/COFF format, and this - support requires changes to DECL, such as putting it in a separate - section. - - -- Macro: SUPPORTS_ONE_ONLY - A C expression which evaluates to true if the target supports - one-only semantics. - - If you don't define this macro, 'varasm.c' provides a default - definition. If 'MAKE_DECL_ONE_ONLY' is defined, the default - definition is '1'; otherwise, it is '0'. Define this macro if you - want to control one-only symbol support with a compiler flag, or if - setting the 'DECL_ONE_ONLY' flag is enough to mark a declaration to - be emitted as one-only. - - -- Target Hook: void TARGET_ASM_ASSEMBLE_VISIBILITY (tree DECL, int - VISIBILITY) - This target hook is a function to output to ASM_OUT_FILE some - commands that will make the symbol(s) associated with DECL have - hidden, protected or internal visibility as specified by - VISIBILITY. - - -- Macro: 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 '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. - - -- Macro: ASM_OUTPUT_EXTERNAL (STREAM, DECL, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - any text necessary for declaring the name of an external symbol - named NAME which is referenced in this compilation but not defined. - The value of 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. - - -- Target Hook: void TARGET_ASM_EXTERNAL_LIBCALL (rtx SYMREF) - This target hook is a function to output to ASM_OUT_FILE an - assembler pseudo-op to declare a library function name external. - The name of the library function is given by SYMREF, which is a - 'symbol_ref'. - - -- Target Hook: void TARGET_ASM_MARK_DECL_PRESERVED (const char - *SYMBOL) - This target hook is a function to output to ASM_OUT_FILE an - assembler directive to annotate SYMBOL as used. The Darwin target - uses the .no_dead_code_strip directive. - - -- Macro: ASM_OUTPUT_LABELREF (STREAM, NAME) - A C statement (sans semicolon) to output to the stdio stream STREAM - a reference in assembler syntax to a label named NAME. This should - add '_' 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 'assemble_name'. - - -- Target Hook: tree TARGET_MANGLE_ASSEMBLER_NAME (const char *NAME) - Given a symbol NAME, perform same mangling as 'varasm.c''s - 'assemble_name', but in memory rather than to a file stream, - returning result as an 'IDENTIFIER_NODE'. Required for correct LTO - symtabs. The default implementation calls the - 'TARGET_STRIP_NAME_ENCODING' hook and then prepends the - 'USER_LABEL_PREFIX', if any. - - -- Macro: ASM_OUTPUT_SYMBOL_REF (STREAM, SYM) - A C statement (sans semicolon) to output a reference to - 'SYMBOL_REF' SYM. If not defined, '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 - 'TARGET_ENCODE_SECTION_INFO'. - - -- Macro: ASM_OUTPUT_LABEL_REF (STREAM, BUF) - A C statement (sans semicolon) to output a reference to BUF, the - result of 'ASM_GENERATE_INTERNAL_LABEL'. If not defined, - 'assemble_name' will be used to output the name of the symbol. - This macro is not used by 'output_asm_label', or the '%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. - - -- Target Hook: void TARGET_ASM_INTERNAL_LABEL (FILE *STREAM, const - char *PREFIX, unsigned long LABELNO) - A function to output to the stdio stream STREAM a label whose name - is made from the string PREFIX and the number 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 '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 - 'ASM_GENERATE_INTERNAL_LABEL'. - - -- Macro: ASM_OUTPUT_DEBUG_LABEL (STREAM, PREFIX, NUM) - A C statement to output to the stdio stream STREAM a debug info - label whose name is made from the string PREFIX and the number 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 - '(*targetm.asm_out.internal_label)' will be used. - - -- Macro: ASM_GENERATE_INTERNAL_LABEL (STRING, PREFIX, NUM) - A C statement to store into the string STRING a label whose name is - made from the string PREFIX and the number NUM. - - This string, when output subsequently by 'assemble_name', should - produce the output that '(*targetm.asm_out.internal_label)' would - produce with the same PREFIX and NUM. - - If the string begins with '*', then 'assemble_name' will output the - rest of the string unchanged. It is often convenient for - 'ASM_GENERATE_INTERNAL_LABEL' to use '*' in this way. If the - string doesn't start with '*', then 'ASM_OUTPUT_LABELREF' gets to - output the string, and may change it. (Of course, - 'ASM_OUTPUT_LABELREF' is also part of your machine description, so - you should know what it does on your machine.) - - -- Macro: ASM_FORMAT_PRIVATE_NAME (OUTVAR, NAME, NUMBER) - A C expression to assign to OUTVAR (which is a variable of type - 'char *') a newly allocated string made from the string NAME and - the number NUMBER, with some suitable punctuation added. Use - 'alloca' to get space for the string. - - The string will be used as an argument to 'ASM_OUTPUT_LABELREF' to - produce an assembler label for an internal static variable whose - name is NAME. Therefore, the string must be such as to result in - valid assembler code. The argument 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. - - -- Macro: ASM_OUTPUT_DEF (STREAM, NAME, VALUE) - A C statement to output to the stdio stream STREAM assembler code - which defines (equates) the symbol NAME to have the value VALUE. - - If 'SET_ASM_OP' is defined, a default definition is provided which - is correct for most systems. - - -- Macro: ASM_OUTPUT_DEF_FROM_DECLS (STREAM, DECL_OF_NAME, - DECL_OF_VALUE) - A C statement to output to the stdio stream STREAM assembler code - which defines (equates) the symbol whose tree node is DECL_OF_NAME - to have the value of the tree node DECL_OF_VALUE. This macro will - be used in preference to 'ASM_OUTPUT_DEF' if it is defined and if - the tree nodes are available. - - If 'SET_ASM_OP' is defined, a default definition is provided which - is correct for most systems. - - -- Macro: TARGET_DEFERRED_OUTPUT_DEFS (DECL_OF_NAME, DECL_OF_VALUE) - A C statement that evaluates to true if the assembler code which - defines (equates) the symbol whose tree node is DECL_OF_NAME to - have the value of the tree node 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 - 'ASM_OUTPUT_DEF' and 'ASM_OUTPUT_DEF_FROM_DECLS'. - - -- Macro: ASM_OUTPUT_WEAK_ALIAS (STREAM, NAME, VALUE) - A C statement to output to the stdio stream STREAM assembler code - which defines (equates) the weak symbol NAME to have the value - VALUE. If VALUE is 'NULL', it defines NAME as an undefined weak - symbol. - - Define this macro if the target only supports weak aliases; define - 'ASM_OUTPUT_DEF' instead if possible. - - -- Macro: OBJC_GEN_METHOD_LABEL (BUF, IS_INST, CLASS_NAME, CAT_NAME, - 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. '_1_Foo'). For methods in categories, the name of - the category is also included in the assembler name (e.g. - '_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. - - BUF is an expression of type 'char *' which gives you a buffer in - which to store the name; its length is as long as CLASS_NAME, - CAT_NAME and SEL_NAME put together, plus 50 characters extra. - - The argument IS_INST specifies whether the method is an instance - method or a class method; CLASS_NAME is the name of the class; - CAT_NAME is the name of the category (or 'NULL' if the method is - not in a category); and 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. - - -File: gccint.info, Node: Initialization, Next: Macros for Initialization, Prev: Label Output, Up: Assembler Format - -17.21.5 How Initialization Functions Are Handled ------------------------------------------------- - -The compiled code for certain languages includes "constructors" (also -called "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 'main' is -called. - - Compiling some languages generates "destructors" (also called -"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. - - The linker must build two lists of these functions--a list of -initialization functions, called '__CTOR_LIST__', and a list of -termination functions, called '__DTOR_LIST__'. - - Each list always begins with an ignored function pointer (which may -hold 0, -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 'crtstuff.c' or '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 '.ctors' and '.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 '.ctors' section. Termination -functions are handled similarly. - - This method will be chosen as the default by 'target-def.h' if -'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 'CTORS_SECTION_ASM_OP' and -'DTORS_SECTION_ASM_OP' to achieve the same effect. - - When arbitrary sections are available, there are two variants, -depending upon how the code in 'crtstuff.c' is called. On systems that -support a ".init" section which is executed at program startup, parts of -'crtstuff.c' are compiled into that section. The program is linked by -the 'gcc' driver like this: - - ld -o OUTPUT_FILE crti.o crtbegin.o ... -lgcc crtend.o crtn.o - - The prologue of a function ('__init') appears in the '.init' section of -'crti.o'; the epilogue appears in 'crtn.o'. Likewise for the function -'__fini' in the ".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 'crtbegin.o' and 'crtend.o' are (for most targets) compiled -from 'crtstuff.c'. They contain, among other things, code fragments -within the '.init' and '.fini' sections that branch to routines in the -'.text' section. The linker will pull all parts of a section together, -which results in a complete '__init' function that invokes the routines -we need at startup. - - To use this variant, you must define the 'INIT_SECTION_ASM_OP' macro -properly. - - If no init section is available, when GCC compiles any function called -'main' (or more accurately, any function designated as a program entry -point by the language front end calling 'expand_main_function'), it -inserts a procedure call to '__main' as the first executable code after -the function prologue. The '__main' function is defined in '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 'ld') and an -'a.out' format must be used. In this case, 'TARGET_ASM_CONSTRUCTOR' is -defined to produce a '.stabs' entry of type 'N_SETT', referencing the -name '__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 "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. 'TARGET_ASM_DESTRUCTOR' is handled similarly. -Since no init section is available, the absence of 'INIT_SECTION_ASM_OP' -causes the compilation of 'main' to call '__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, '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 '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 '__main' as described above. In order to use this method, -'use_collect2' must be defined in the target in 'config.gcc'. - - The following section describes the specific macros that control and -customize the handling of initialization and termination functions. - - -File: gccint.info, Node: Macros for Initialization, Next: Instruction Output, Prev: Initialization, Up: Assembler Format - -17.21.6 Macros Controlling Initialization Routines --------------------------------------------------- - -Here are the macros that control how the compiler handles initialization -and termination functions: - - -- Macro: 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 'crtstuff.c' and 'libgcc2.c' arrange to run the initialization - functions. - - -- Macro: HAS_INIT_SECTION - If defined, 'main' will not call '__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 'INIT_SECTION_ASM_OP'. - - -- Macro: LD_INIT_SWITCH - If defined, a C string constant for a switch that tells the linker - that the following symbol is an initialization routine. - - -- Macro: LD_FINI_SWITCH - If defined, a C string constant for a switch that tells the linker - that the following symbol is a finalization routine. - - -- Macro: COLLECT_SHARED_INIT_FUNC (STREAM, 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 FUNC, which takes no arguments. If not defined, and - the object format requires an explicit initialization function, - then a function called '_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. - - -- Macro: COLLECT_SHARED_FINI_FUNC (STREAM, 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 FUNC, which takes no arguments. If not - defined, and the object format requires an explicit finalization - function, then a function called '_GLOBAL__DD' will be generated. - - -- Macro: INVOKE__main - If defined, 'main' will call '__main' despite the presence of - '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. - - -- Macro: SUPPORTS_INIT_PRIORITY - If nonzero, the C++ '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 'init_priority' attribute. - - -- 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 'collect2'. - - -- Target Hook: void TARGET_ASM_CONSTRUCTOR (rtx SYMBOL, int PRIORITY) - If defined, a function that outputs assembler code to arrange to - call the function referenced by SYMBOL at initialization time. - - Assume that SYMBOL is a 'SYMBOL_REF' for a function taking no - arguments and with no return value. If the target supports - initialization priorities, PRIORITY is a value between 0 and - 'MAX_INIT_PRIORITY'; otherwise it must be '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 'CTORS_SECTION_ASM_OP', or (3) 'USE_COLLECT2' is - not defined. - - -- Target Hook: void TARGET_ASM_DESTRUCTOR (rtx SYMBOL, int PRIORITY) - This is like 'TARGET_ASM_CONSTRUCTOR' but used for termination - functions rather than initialization functions. - - If 'TARGET_HAVE_CTORS_DTORS' is true, the initialization routine -generated for the generated object file will have static linkage. - - If your system uses 'collect2' as the means of processing constructors, -then that program normally uses 'nm' to scan an object file for -constructor functions to be called. - - On certain kinds of systems, you can define this macro to make -'collect2' work faster (and, in some cases, make it work at all): - - -- Macro: OBJECT_FORMAT_COFF - Define this macro if the system uses COFF (Common Object File - Format) object files, so that 'collect2' can assume this format and - scan object files directly for dynamic constructor/destructor - functions. - - This macro is effective only in a native compiler; 'collect2' as - part of a cross compiler always uses 'nm' for the target machine. - - -- Macro: REAL_NM_FILE_NAME - Define this macro as a C string constant containing the file name - to use to execute 'nm'. The default is to search the path normally - for 'nm'. - - -- Macro: NM_FLAGS - 'collect2' calls 'nm' to scan object files for static constructors - and destructors and LTO info. By default, '-n' is passed. Define - 'NM_FLAGS' to a C string constant if other options are needed to - get the same output format as GNU 'nm -n' produces. - - 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: - - -- Macro: LDD_SUFFIX - Define this macro to a C string constant containing the name of the - program which lists dynamic dependencies, like 'ldd' under SunOS 4. - - -- Macro: PARSE_LDD_OUTPUT (PTR) - Define this macro to be C code that extracts filenames from the - output of the program denoted by 'LDD_SUFFIX'. PTR is a variable - of type 'char *' that points to the beginning of a line of output - from 'LDD_SUFFIX'. If the line lists a dynamic dependency, the - code must advance PTR to the beginning of the filename on that - line. Otherwise, it must set PTR to 'NULL'. - - -- Macro: SHLIB_SUFFIX - Define this macro to a C string constant containing the default - shared library extension of the target (e.g., '".so"'). 'collect2' - strips version information after this suffix when generating global - constructor and destructor names. This define is only needed on - targets that use 'collect2' to process constructors and - destructors. - - -File: gccint.info, Node: Instruction Output, Next: Dispatch Tables, Prev: Macros for Initialization, Up: Assembler Format - -17.21.7 Output of Assembler Instructions ----------------------------------------- - -This describes assembler instruction output. - - -- Macro: 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. - - -- Macro: 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 'asm' option in declarations - to refer to registers using alternate names. - - -- Macro: OVERLAPPING_REGISTER_NAMES - If defined, a C initializer for an array of structures containing a - name, a register number and a count of the number of consecutive - machine registers the name overlaps. This macro defines additional - names for hard registers, thus allowing the 'asm' option in - declarations to refer to registers using alternate names. Unlike - 'ADDITIONAL_REGISTER_NAMES', this macro should be used when the - register name implies multiple underlying registers. - - This macro should be used when it is important that a clobber in an - 'asm' statement clobbers all the underlying values implied by the - register name. For example, on ARM, clobbering the - double-precision VFP register "d0" implies clobbering both - single-precision registers "s0" and "s1". - - -- Macro: ASM_OUTPUT_OPCODE (STREAM, 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 STREAM. The - macro-operand PTR is a variable of type '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 STREAM, performing any translation you desire, and - increment the variable 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 '%'-sequences to substitute operands, - you must take care of the substitution yourself. Just be sure to - increment PTR over whatever text should not be output normally. - - If you need to look at the operand values, they can be found as the - elements of 'recog_data.operand'. - - If the macro definition does nothing, the instruction is output in - the usual way. - - -- Macro: FINAL_PRESCAN_INSN (INSN, OPVEC, NOPERANDS) - If defined, a C statement to be executed just prior to the output - of assembler code for INSN, to modify the extracted operands so - they will be output differently. - - Here the argument OPVEC is the vector containing the operands - extracted from INSN, and 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. - - -- Target Hook: void TARGET_ASM_FINAL_POSTSCAN_INSN (FILE *FILE, rtx - INSN, rtx *OPVEC, int NOPERANDS) - If defined, this target hook is a function which is executed just - after the output of assembler code for INSN, to change the mode of - the assembler if necessary. - - Here the argument OPVEC is the vector containing the operands - extracted from INSN, and NOPERANDS is the number of elements of the - vector which contain meaningful data for this insn. The contents - of this vector are what was used to convert the insn template into - assembler code, so you can change the assembler mode by checking - the contents of the vector. - - -- Macro: PRINT_OPERAND (STREAM, X, CODE) - A C compound statement to output to stdio stream STREAM the - assembler syntax for an instruction operand X. X is an RTL - expression. - - 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. CODE comes from the - '%' specification that was used to request printing of the operand. - If the specification was just '%DIGIT' then CODE is 0; if the - specification was '%LTR DIGIT' then CODE is the ASCII code for LTR. - - If X is a register, this macro should print the register's name. - The names can be found in an array 'reg_names' whose type is 'char - *[]'. 'reg_names' is initialized from 'REGISTER_NAMES'. - - When the machine description has a specification '%PUNCT' (a '%' - followed by a punctuation character), this macro is called with a - null pointer for X and the punctuation character for CODE. - - -- Macro: PRINT_OPERAND_PUNCT_VALID_P (CODE) - A C expression which evaluates to true if CODE is a valid - punctuation character for use in the 'PRINT_OPERAND' macro. If - 'PRINT_OPERAND_PUNCT_VALID_P' is not defined, it means that no - punctuation characters (except for the standard one, '%') are used - in this way. - - -- Macro: PRINT_OPERAND_ADDRESS (STREAM, X) - A C compound statement to output to stdio stream STREAM the - assembler syntax for an instruction operand that is a memory - reference whose address is X. X is an RTL expression. - - On some machines, the syntax for a symbolic address depends on the - section that the address refers to. On these machines, define the - hook 'TARGET_ENCODE_SECTION_INFO' to store the information into the - 'symbol_ref', and then check for it here. *Note Assembler - Format::. - - -- Macro: DBR_OUTPUT_SEQEND (FILE) - A C statement, to be executed after all slot-filler instructions - have been output. If necessary, call '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). - - 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 'final_sequence' is null when not processing a sequence, -otherwise it contains the 'sequence' rtx being output. - - -- Macro: REGISTER_PREFIX - -- Macro: LOCAL_LABEL_PREFIX - -- Macro: USER_LABEL_PREFIX - -- Macro: IMMEDIATE_PREFIX - If defined, C string expressions to be used for the '%R', '%L', - '%U', and '%I' options of 'asm_fprintf' (see 'final.c'). These are - useful when a single 'md' file must support multiple assembler - formats. In that case, the various 'tm.h' files can define these - macros differently. - - -- Macro: ASM_FPRINTF_EXTENSIONS (FILE, ARGPTR, FORMAT) - If defined this macro should expand to a series of 'case' - statements which will be parsed inside the 'switch' statement of - the '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 - FILE. The varargs input pointer is ARGPTR and the rest of the - format string, starting the character after the one that is being - switched upon, is pointed to by FORMAT. - - -- Macro: 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 - '{option0|option1|option2...}' - in the output templates of patterns (*note Output Template::) or in - the first argument of 'asm_fprintf'. This construct outputs - 'option0', 'option1', 'option2', etc., if the value of - '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 - 'ASSEMBLER_DIALECT', the construct outputs nothing. If it's needed - to print curly braces or '|' character in assembler output - directly, '%{', '%}' and '%|' can be used. - - If you do not define this macro, the characters '{', '|' and '}' do - not have any special meaning when used in templates or operands to - 'asm_fprintf'. - - Define the macros 'REGISTER_PREFIX', 'LOCAL_LABEL_PREFIX', - 'USER_LABEL_PREFIX' and 'IMMEDIATE_PREFIX' if you can express the - variations in assembler language syntax with that mechanism. - Define 'ASSEMBLER_DIALECT' and use the '{option0|option1}' syntax - if the syntax variant are larger and involve such things as - different opcodes or operand order. - - -- Macro: ASM_OUTPUT_REG_PUSH (STREAM, REGNO) - A C expression to output to STREAM some assembler code which will - push hard register number REGNO onto the stack. The code need not - be optimal, since this macro is used only when profiling. - - -- Macro: ASM_OUTPUT_REG_POP (STREAM, REGNO) - A C expression to output to STREAM some assembler code which will - pop hard register number REGNO off of the stack. The code need not - be optimal, since this macro is used only when profiling. - - -File: gccint.info, Node: Dispatch Tables, Next: Exception Region Output, Prev: Instruction Output, Up: Assembler Format - -17.21.8 Output of Dispatch Tables ---------------------------------- - -This concerns dispatch tables. - - -- Macro: ASM_OUTPUT_ADDR_DIFF_ELT (STREAM, BODY, VALUE, REL) - A C statement to output to the stdio stream STREAM an assembler - pseudo-instruction to generate a difference between two labels. - VALUE and REL are the numbers of two internal labels. The - definitions of these labels are output using - '(*targetm.asm_out.internal_label)', and they must be printed in - the same way here. For example, - - fprintf (STREAM, "\t.word L%d-L%d\n", - VALUE, REL) - - 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. BODY is the body of the 'ADDR_DIFF_VEC'; it is - provided so that the mode and flags can be read. - - -- Macro: ASM_OUTPUT_ADDR_VEC_ELT (STREAM, 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 STREAM an assembler pseudo-instruction to generate a - reference to a label. VALUE is the number of an internal label - whose definition is output using - '(*targetm.asm_out.internal_label)'. For example, - - fprintf (STREAM, "\t.word L%d\n", VALUE) - - -- Macro: ASM_OUTPUT_CASE_LABEL (STREAM, PREFIX, NUM, TABLE) - Define this if the label before a jump-table needs to be output - specially. The first three arguments are the same as for - '(*targetm.asm_out.internal_label)'; the fourth argument is the - jump-table which follows (a 'jump_table_data' containing an - 'addr_vec' or 'addr_diff_vec'). - - This feature is used on system V to output a 'swbeg' statement for - the table. - - If this macro is not defined, these labels are output with - '(*targetm.asm_out.internal_label)'. - - -- Macro: ASM_OUTPUT_CASE_END (STREAM, NUM, 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 STREAM. The argument TABLE is - the jump-table insn, and 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. - - -- Target Hook: void TARGET_ASM_EMIT_UNWIND_LABEL (FILE *STREAM, tree - DECL, int FOR_EH, int 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 DECL, to the stdio stream STREAM. The third - argument, FOR_EH, is a boolean: true if this is for an exception - table. The fourth argument, 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. - - -- Target Hook: void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (FILE *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. - - -- Target Hook: void TARGET_ASM_EMIT_EXCEPT_PERSONALITY (rtx - PERSONALITY) - If the target implements 'TARGET_ASM_UNWIND_EMIT', this hook may be - used to emit a directive to install a personality hook into the - unwind info. This hook should not be used if dwarf2 unwind info is - used. - - -- Target Hook: void TARGET_ASM_UNWIND_EMIT (FILE *STREAM, rtx INSN) - This target hook emits assembly directives required to unwind the - given instruction. This is only used when - 'TARGET_EXCEPT_UNWIND_INFO' returns 'UI_TARGET'. - - -- Target Hook: bool TARGET_ASM_UNWIND_EMIT_BEFORE_INSN - True if the 'TARGET_ASM_UNWIND_EMIT' hook should be called before - the assembly for INSN has been emitted, false if the hook should be - called afterward. - - -File: gccint.info, Node: Exception Region Output, Next: Alignment Output, Prev: Dispatch Tables, Up: Assembler Format - -17.21.9 Assembler Commands for Exception Regions ------------------------------------------------- - -This describes commands marking the start and the end of an exception -region. - - -- Macro: 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. '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. - - -- Macro: 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 'TARGET_ASM_NAMED_SECTION' is also - defined. - - -- Macro: 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. - - -- Macro: MASK_RETURN_ADDR - An rtx used to mask the return address found via 'RETURN_ADDR_RTX', - so that it does not contain any extraneous set bits in it. - - -- Macro: 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 - 'INCOMING_RETURN_ADDR_RTX' and 'OBJECT_FORMAT_ELF'), GCC will - provide a default definition of 1. - - -- Common Target Hook: enum unwind_info_type TARGET_EXCEPT_UNWIND_INFO - (struct gcc_options *OPTS) - This hook defines the mechanism that will be used for exception - handling by the target. If the target has ABI specified unwind - tables, the hook should return 'UI_TARGET'. If the target is to - use the 'setjmp'/'longjmp'-based exception handling scheme, the - hook should return 'UI_SJLJ'. If the target supports DWARF 2 frame - unwind information, the hook should return 'UI_DWARF2'. - - A target may, if exceptions are disabled, choose to return - 'UI_NONE'. This may end up simplifying other parts of - target-specific code. The default implementation of this hook - never returns 'UI_NONE'. - - Note that the value returned by this hook should be constant. It - should not depend on anything except the command-line switches - described by OPTS. In particular, the setting 'UI_SJLJ' must be - fixed at compiler start-up as C pre-processor macros and builtin - functions related to exception handling are set up depending on - this setting. - - The default implementation of the hook first honors the - '--enable-sjlj-exceptions' configure option, then - 'DWARF2_UNWIND_INFO', and finally defaults to 'UI_SJLJ'. If - 'DWARF2_UNWIND_INFO' depends on command-line options, the target - must define this hook so that OPTS is used correctly. - - -- Common Target Hook: bool TARGET_UNWIND_TABLES_DEFAULT - This variable should be set to 'true' if the target ABI requires - unwinding tables even when exceptions are not used. It must not be - modified by command-line option processing. - - -- Macro: DONT_USE_BUILTIN_SETJMP - Define this macro to 1 if the 'setjmp'/'longjmp'-based scheme - should use the 'setjmp'/'longjmp' functions from the C library - instead of the '__builtin_setjmp'/'__builtin_longjmp' machinery. - - -- Macro: JMP_BUF_SIZE - This macro has no effect unless 'DONT_USE_BUILTIN_SETJMP' is also - defined. Define this macro if the default size of 'jmp_buf' buffer - for the 'setjmp'/'longjmp'-based exception handling mechanism is - not large enough, or if it is much too large. The default size is - 'FIRST_PSEUDO_REGISTER * sizeof(void *)'. - - -- Macro: 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 'UNITS_PER_WORD'. The definition should be the - negative minimum alignment if 'STACK_GROWS_DOWNWARD' is defined, - and the positive minimum alignment otherwise. *Note SDB and - DWARF::. Only applicable if the target supports DWARF 2 frame - unwind information. - - -- 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 'EH_FRAME_SECTION_NAME' is - defined, and true otherwise. - - -- Target Hook: rtx TARGET_DWARF_REGISTER_SPAN (rtx 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 'NULL_RTX'. If not defined, the default is to return - 'NULL_RTX'. - - -- Target Hook: void TARGET_INIT_DWARF_REG_SIZES_EXTRA (tree ADDRESS) - If some registers are represented in Dwarf-2 unwind information in - multiple pieces, define this hook to fill in information about the - sizes of those pieces in the table used by the unwinder at runtime. - It will be called by 'expand_builtin_init_dwarf_reg_sizes' after - filling in a single size corresponding to each hard register; - ADDRESS is the address of the table. - - -- Target Hook: bool TARGET_ASM_TTYPE (rtx SYM) - This hook is used to output a reference from a frame unwinding - table to the type_info object identified by SYM. It should return - 'true' if the reference was output. Returning 'false' will cause - the reference to be output using the normal Dwarf2 routines. - - -- Target Hook: bool TARGET_ARM_EABI_UNWINDER - This flag should be set to 'true' on targets that use an ARM EABI - based unwinding library, and 'false' on other targets. This - effects the format of unwinding tables, and how the unwinder in - entered after running a cleanup. The default is 'false'. - - -File: gccint.info, Node: Alignment Output, Prev: Exception Region Output, Up: Assembler Format - -17.21.10 Assembler Commands for Alignment ------------------------------------------ - -This describes commands for alignment. - - -- Macro: JUMP_ALIGN (LABEL) - The alignment (log base 2) to put in front of 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 LABEL parameter, it is better - to set the variable ALIGN_JUMPS in the target's - 'TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the - user's selection in ALIGN_JUMPS in a 'JUMP_ALIGN' implementation. - - -- Target Hook: int TARGET_ASM_JUMP_ALIGN_MAX_SKIP (rtx LABEL) - The maximum number of bytes to skip before LABEL when applying - 'JUMP_ALIGN'. This works only if 'ASM_OUTPUT_MAX_SKIP_ALIGN' is - defined. - - -- Macro: LABEL_ALIGN_AFTER_BARRIER (LABEL) - The alignment (log base 2) to put in front of LABEL, which follows - a '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. - - -- Target Hook: int TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP (rtx - LABEL) - The maximum number of bytes to skip before LABEL when applying - 'LABEL_ALIGN_AFTER_BARRIER'. This works only if - 'ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. - - -- Macro: LOOP_ALIGN (LABEL) - The alignment (log base 2) to put in front of LABEL that heads a - frequently executed basic block (usually the header of a loop). - - 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 LABEL parameter, it is better - to set the variable 'align_loops' in the target's - 'TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the - user's selection in 'align_loops' in a 'LOOP_ALIGN' implementation. - - -- Target Hook: int TARGET_ASM_LOOP_ALIGN_MAX_SKIP (rtx LABEL) - The maximum number of bytes to skip when applying 'LOOP_ALIGN' to - LABEL. This works only if 'ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. - - -- Macro: LABEL_ALIGN (LABEL) - The alignment (log base 2) to put in front of LABEL. If - 'LABEL_ALIGN_AFTER_BARRIER' / 'LOOP_ALIGN' specify a different - alignment, the maximum of the specified values is used. - - Unless it's necessary to inspect the LABEL parameter, it is better - to set the variable 'align_labels' in the target's - 'TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the - user's selection in 'align_labels' in a 'LABEL_ALIGN' - implementation. - - -- Target Hook: int TARGET_ASM_LABEL_ALIGN_MAX_SKIP (rtx LABEL) - The maximum number of bytes to skip when applying 'LABEL_ALIGN' to - LABEL. This works only if 'ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. - - -- Macro: ASM_OUTPUT_SKIP (STREAM, NBYTES) - A C statement to output to the stdio stream STREAM an assembler - instruction to advance the location counter by NBYTES bytes. Those - bytes should be zero when loaded. NBYTES will be a C expression of - type 'unsigned HOST_WIDE_INT'. - - -- Macro: ASM_NO_SKIP_IN_TEXT - Define this macro if '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. - - -- Macro: ASM_OUTPUT_ALIGN (STREAM, POWER) - A C statement to output to the stdio stream STREAM an assembler - command to advance the location counter to a multiple of 2 to the - POWER bytes. POWER will be a C expression of type 'int'. - - -- Macro: ASM_OUTPUT_ALIGN_WITH_NOP (STREAM, POWER) - Like 'ASM_OUTPUT_ALIGN', except that the "nop" instruction is used - for padding, if necessary. - - -- Macro: ASM_OUTPUT_MAX_SKIP_ALIGN (STREAM, POWER, MAX_SKIP) - A C statement to output to the stdio stream STREAM an assembler - command to advance the location counter to a multiple of 2 to the - POWER bytes, but only if MAX_SKIP or fewer bytes are needed to - satisfy the alignment request. POWER and MAX_SKIP will be a C - expression of type 'int'. - - -File: gccint.info, Node: Debugging Info, Next: Floating Point, Prev: Assembler Format, Up: Target Macros - -17.22 Controlling Debugging Information Format -============================================== - -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. - - -File: gccint.info, Node: All Debuggers, Next: DBX Options, Up: Debugging Info - -17.22.1 Macros Affecting All Debugging Formats ----------------------------------------------- - -These macros affect all debugging formats. - - -- Macro: DBX_REGISTER_NUMBER (REGNO) - A C expression that returns the DBX register number for the - compiler register number REGNO. In the default macro provided, the - value of this expression will be 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 _must_ have - consecutive numbers after renumbering with '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 'DBX_REGISTER_NUMBER' in way that - does not preserve register pairs, then what you must do instead is - redefine the actual register numbering scheme. - - -- Macro: DEBUGGER_AUTO_OFFSET (X) - A C expression that returns the integer offset value for an - automatic variable having address X (an RTL expression). The - default computation assumes that 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 '-g' options is used. - - -- Macro: DEBUGGER_ARG_OFFSET (OFFSET, X) - A C expression that returns the integer offset value for an - argument having address X (an RTL expression). The nominal offset - is OFFSET. - - -- Macro: PREFERRED_DEBUGGING_TYPE - A C expression that returns the type of debugging output GCC should - produce when the user specifies just '-g'. Define this if you have - arranged for GCC to support more than one format of debugging - output. Currently, the allowable values are 'DBX_DEBUG', - 'SDB_DEBUG', 'DWARF_DEBUG', 'DWARF2_DEBUG', 'XCOFF_DEBUG', - 'VMS_DEBUG', and 'VMS_AND_DWARF2_DEBUG'. - - When the user specifies '-ggdb', GCC normally also uses the value - of this macro to select the debugging output format, but with two - exceptions. If 'DWARF2_DEBUGGING_INFO' is defined, GCC uses the - value 'DWARF2_DEBUG'. Otherwise, if 'DBX_DEBUGGING_INFO' is - defined, GCC uses '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 - '-gstabs', '-gcoff', '-gdwarf-2', '-gxcoff', or '-gvms'. - - -File: gccint.info, Node: DBX Options, Next: DBX Hooks, Prev: All Debuggers, Up: Debugging Info - -17.22.2 Specific Options for DBX Output ---------------------------------------- - -These are specific options for DBX output. - - -- Macro: DBX_DEBUGGING_INFO - Define this macro if GCC should produce debugging output for DBX in - response to the '-g' option. - - -- Macro: XCOFF_DEBUGGING_INFO - Define this macro if GCC should produce XCOFF format debugging - output in response to the '-g' option. This is a variant of DBX - format. - - -- Macro: 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. - - -- Macro: DEBUG_SYMS_TEXT - Define this macro if all '.stabs' commands should be output while - in the text section. - - -- Macro: ASM_STABS_OP - A C string constant, including spacing, naming the assembler pseudo - op to use instead of '"\t.stabs\t"' to define an ordinary debugging - symbol. If you don't define this macro, '"\t.stabs\t"' is used. - This macro applies only to DBX debugging information format. - - -- Macro: ASM_STABD_OP - A C string constant, including spacing, naming the assembler pseudo - op to use instead of '"\t.stabd\t"' to define a debugging symbol - whose value is the current location. If you don't define this - macro, '"\t.stabd\t"' is used. This macro applies only to DBX - debugging information format. - - -- Macro: ASM_STABN_OP - A C string constant, including spacing, naming the assembler pseudo - op to use instead of '"\t.stabn\t"' to define a debugging symbol - with no name. If you don't define this macro, '"\t.stabn\t"' is - used. This macro applies only to DBX debugging information format. - - -- Macro: DBX_NO_XREFS - Define this macro if DBX on your system does not support the - construct 'xsTAGNAME'. On some systems, this construct is used to - describe a forward reference to a structure named TAGNAME. On - other systems, this construct is not supported at all. - - -- Macro: DBX_CONTIN_LENGTH - A symbol name in DBX-format debugging information is normally - continued (split into two separate '.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. - - -- Macro: DBX_CONTIN_CHAR - Normally continuation is indicated by adding a '\' character to the - end of a '.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. - - -- Macro: DBX_STATIC_STAB_DATA_SECTION - Define this macro if it is necessary to go to the data section - before outputting the '.stabs' pseudo-op for a non-global static - variable. - - -- Macro: DBX_TYPE_DECL_STABS_CODE - The value to use in the "code" field of the '.stabs' directive for - a typedef. The default is 'N_LSYM'. - - -- Macro: DBX_STATIC_CONST_VAR_CODE - The value to use in the "code" field of the '.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 'N_FUN'. - - -- Macro: DBX_REGPARM_STABS_CODE - The value to use in the "code" field of the '.stabs' directive for - a parameter passed in registers. DBX format does not provide any - "right" way to do this. The default is 'N_RSYM'. - - -- Macro: 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 ''P''. - - -- Macro: 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. - - -- Macro: DBX_BLOCKS_FUNCTION_RELATIVE - Define this macro, with value 1, if the value of a symbol - describing the scope of a block ('N_LBRAC' or 'N_RBRAC') should be - relative to the start of the enclosing function. Normally, GCC - uses an absolute address. - - -- Macro: DBX_LINES_FUNCTION_RELATIVE - Define this macro, with value 1, if the value of a symbol - indicating the current line number ('N_SLINE') should be relative - to the start of the enclosing function. Normally, GCC uses an - absolute address. - - -- Macro: DBX_USE_BINCL - Define this macro if GCC should generate 'N_BINCL' and '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 - 'N_BINCL' or 'N_EINCL' stabs, and it outputs a single number for a - type number. - - -File: gccint.info, Node: DBX Hooks, Next: File Names and DBX, Prev: DBX Options, Up: Debugging Info - -17.22.3 Open-Ended Hooks for DBX Format ---------------------------------------- - -These are hooks for DBX format. - - -- Macro: DBX_OUTPUT_SOURCE_LINE (STREAM, LINE, COUNTER) - A C statement to output DBX debugging information before code for - line number LINE of the current source file to the stdio stream - STREAM. 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 - 'DBX_LINES_FUNCTION_RELATIVE'. - - -- Macro: NO_DBX_FUNCTION_END - Some stabs encapsulation formats (in particular ECOFF), cannot - handle the '.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. - - -- Macro: NO_DBX_BNSYM_ENSYM - Some assemblers cannot handle the '.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. - - -File: gccint.info, Node: File Names and DBX, Next: SDB and DWARF, Prev: DBX Hooks, Up: Debugging Info - -17.22.4 File Names in DBX Format --------------------------------- - -This describes file names in DBX format. - - -- Macro: DBX_OUTPUT_MAIN_SOURCE_FILENAME (STREAM, NAME) - A C statement to output DBX debugging information to the stdio - stream STREAM, which indicates that file 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 'assemble_name (stream, - ltext_label_name)' to do so. If you do this, you must also set the - variable USED_LTEXT_LABEL_NAME to 'true'. - - -- Macro: 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. - - -- Macro: 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 'N_OPT' stab at the beginning of every source file, - with 'gcc2_compiled.' for the string and value 0. - - -- Macro: DBX_OUTPUT_MAIN_SOURCE_FILE_END (STREAM, NAME) - A C statement to output DBX debugging information at the end of - compilation of the main source file NAME. Output should be written - to the stdio stream STREAM. - - If you don't define this macro, nothing special is output at the - end of compilation, which is correct for most machines. - - -- Macro: DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END - Define this macro _instead of_ defining - 'DBX_OUTPUT_MAIN_SOURCE_FILE_END', if what needs to be output at - the end of compilation is an 'N_SO' stab with an empty string, - whose value is the highest absolute text address in the file. - - -File: gccint.info, Node: SDB and DWARF, Next: VMS Debug, Prev: File Names and DBX, Up: Debugging Info - -17.22.5 Macros for SDB and DWARF Output ---------------------------------------- - -Here are macros for SDB and DWARF output. - - -- Macro: SDB_DEBUGGING_INFO - Define this macro if GCC should produce COFF-style debugging output - for SDB in response to the '-g' option. - - -- Macro: DWARF2_DEBUGGING_INFO - Define this macro if GCC should produce dwarf version 2 format - debugging output in response to the '-g' option. - - -- Target Hook: int TARGET_DWARF_CALLING_CONVENTION (const_tree - FUNCTION) - Define this to enable the dwarf attribute - 'DW_AT_calling_convention' to be emitted for each function. - Instead of an integer return the enum value for the 'DW_CC_' - tag. - - To support optional call frame debugging information, you must also - define 'INCOMING_RETURN_ADDR_RTX' and either set - 'RTX_FRAME_RELATED_P' on the prologue insns if you use RTL for the - prologue, or call 'dwarf2out_def_cfa' and 'dwarf2out_reg_save' as - appropriate from 'TARGET_ASM_FUNCTION_PROLOGUE' if you don't. - - -- Macro: DWARF2_FRAME_INFO - Define this macro to a nonzero value if GCC should always output - Dwarf 2 frame information. If 'TARGET_EXCEPT_UNWIND_INFO' (*note - Exception Region Output::) returns 'UI_DWARF2', and exceptions are - enabled, GCC will output this information not matter how you define - 'DWARF2_FRAME_INFO'. - - -- Target Hook: enum unwind_info_type TARGET_DEBUG_UNWIND_INFO (void) - This hook defines the mechanism that will be used for describing - frame unwind information to the debugger. Normally the hook will - return 'UI_DWARF2' if DWARF 2 debug information is enabled, and - return 'UI_NONE' otherwise. - - A target may return 'UI_DWARF2' even when DWARF 2 debug information - is disabled in order to always output DWARF 2 frame information. - - A target may return 'UI_TARGET' if it has ABI specified unwind - tables. This will suppress generation of the normal debug frame - unwind information. - - -- Macro: 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. - - -- Target Hook: bool TARGET_WANT_DEBUG_PUB_SECTIONS - True if the '.debug_pubtypes' and '.debug_pubnames' sections should - be emitted. These sections are not used on most platforms, and in - particular GDB does not use them. - - -- Target Hook: bool TARGET_FORCE_AT_COMP_DIR - True if the 'DW_AT_comp_dir' attribute should be emitted for each - compilation unit. This attribute is required for the darwin linker - to emit debug information. - - -- Target Hook: bool TARGET_DELAY_SCHED2 - True if sched2 is not to be run at its normal place. This usually - means it will be run as part of machine-specific reorg. - - -- Target Hook: bool TARGET_DELAY_VARTRACK - True if vartrack is not to be run at its normal place. This - usually means it will be run as part of machine-specific reorg. - - -- Macro: ASM_OUTPUT_DWARF_DELTA (STREAM, SIZE, LABEL1, LABEL2) - A C statement to issue assembly directives that create a difference - LAB1 minus LAB2, using an integer of the given SIZE. - - -- Macro: ASM_OUTPUT_DWARF_VMS_DELTA (STREAM, SIZE, LABEL1, LABEL2) - A C statement to issue assembly directives that create a difference - between the two given labels in system defined units, e.g. - instruction slots on IA64 VMS, using an integer of the given size. - - -- Macro: ASM_OUTPUT_DWARF_OFFSET (STREAM, SIZE, LABEL, SECTION) - A C statement to issue assembly directives that create a - section-relative reference to the given LABEL, using an integer of - the given SIZE. The label is known to be defined in the given - SECTION. - - -- Macro: ASM_OUTPUT_DWARF_PCREL (STREAM, SIZE, LABEL) - A C statement to issue assembly directives that create a - self-relative reference to the given LABEL, using an integer of the - given SIZE. - - -- Macro: ASM_OUTPUT_DWARF_TABLE_REF (LABEL) - A C statement to issue assembly directives that create a reference - to the DWARF table identifier LABEL from the current section. This - is used on some systems to avoid garbage collecting a DWARF table - which is referenced by a function. - - -- Target Hook: void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *FILE, int - SIZE, rtx X) - If defined, this target hook is a function which outputs a - DTP-relative reference to the given TLS symbol of the specified - size. - - -- Macro: PUT_SDB_ ... - Define these macros to override the assembler syntax for the - special SDB assembler directives. See 'sdbout.c' for a list of - these macros and their arguments. If the standard syntax is used, - you need not define them yourself. - - -- Macro: 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 '\n'). It is not necessary to - define a new set of 'PUT_SDB_OP' macros if this is the only change - required. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: SDB_OUTPUT_SOURCE_LINE (STREAM, LINE) - A C statement to output SDB debugging information before code for - line number LINE of the current source file to the stdio stream - STREAM. The default is to emit an '.ln' directive. - - -File: gccint.info, Node: VMS Debug, Prev: SDB and DWARF, Up: Debugging Info - -17.22.6 Macros for VMS Debug Format ------------------------------------ - -Here are macros for VMS debug format. - - -- Macro: VMS_DEBUGGING_INFO - Define this macro if GCC should produce debugging output for VMS in - response to the '-g' option. The default behavior for VMS is to - generate minimal debug info for a traceback in the absence of '-g' - unless explicitly overridden with '-g0'. This behavior is - controlled by 'TARGET_OPTION_OPTIMIZATION' and - 'TARGET_OPTION_OVERRIDE'. - - -File: gccint.info, Node: Floating Point, Next: Mode Switching, Prev: Debugging Info, Up: Target Macros - -17.23 Cross Compilation and Floating Point -========================================== - -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 '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. - - -- Macro: 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 'struct' containing - an array of 'HOST_WIDE_INT', but all code should treat it as an - opaque quantity. - - -- Macro: int REAL_VALUES_EQUAL (REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) - Compares for equality the two values, X and Y. If the target - floating point format supports negative zeroes and/or NaNs, - 'REAL_VALUES_EQUAL (-0.0, 0.0)' is true, and 'REAL_VALUES_EQUAL - (NaN, NaN)' is false. - - -- Macro: int REAL_VALUES_LESS (REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) - Tests whether X is less than Y. - - -- Macro: HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE X) - Truncates X to a signed integer, rounding toward zero. - - -- Macro: unsigned HOST_WIDE_INT REAL_VALUE_UNSIGNED_FIX - (REAL_VALUE_TYPE X) - Truncates X to an unsigned integer, rounding toward zero. If X is - negative, returns zero. - - -- Macro: REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *STRING, enum - machine_mode MODE) - Converts STRING into a floating point number in the target - machine's representation for mode MODE. This routine can handle - both decimal and hexadecimal floating point constants, using the - syntax defined by the C language for both. - - -- Macro: int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE X) - Returns 1 if X is negative (including negative zero), 0 otherwise. - - -- Macro: int REAL_VALUE_ISINF (REAL_VALUE_TYPE X) - Determines whether X represents infinity (positive or negative). - - -- Macro: int REAL_VALUE_ISNAN (REAL_VALUE_TYPE X) - Determines whether X represents a "NaN" (not-a-number). - - -- Macro: void REAL_ARITHMETIC (REAL_VALUE_TYPE OUTPUT, enum tree_code - CODE, REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) - Calculates an arithmetic operation on the two floating point values - X and Y, storing the result in OUTPUT (which must be a variable). - - The operation to be performed is specified by CODE. Only the - following codes are supported: 'PLUS_EXPR', 'MINUS_EXPR', - 'MULT_EXPR', 'RDIV_EXPR', 'MAX_EXPR', 'MIN_EXPR'. - - If 'REAL_ARITHMETIC' is asked to evaluate division by zero and the - target's floating point format cannot represent infinity, it will - call 'abort'. Callers should check for this situation first, using - 'MODE_HAS_INFINITIES'. *Note Storage Layout::. - - -- Macro: REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE X) - Returns the negative of the floating point value X. - - -- Macro: REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE X) - Returns the absolute value of X. - - -- Macro: void REAL_VALUE_TO_INT (HOST_WIDE_INT LOW, HOST_WIDE_INT - HIGH, REAL_VALUE_TYPE X) - Converts a floating point value X into a double-precision integer - which is then stored into LOW and HIGH. If the value is not - integral, it is truncated. - - -- Macro: void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE X, HOST_WIDE_INT - LOW, HOST_WIDE_INT HIGH, enum machine_mode MODE) - Converts a double-precision integer found in LOW and HIGH, into a - floating point value which is then stored into X. The value is - truncated to fit in mode MODE. - - -File: gccint.info, Node: Mode Switching, Next: Target Attributes, Prev: Floating Point, Up: Target Macros - -17.24 Mode Switching Instructions -================================= - -The following macros control mode switching optimizations: - - -- Macro: OPTIMIZE_MODE_SWITCHING (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 - 'TARGET_MACHINE_DEPENDENT_REORG'. - - You can have multiple entities that are mode-switched, and select - at run time which entities actually need it. - 'OPTIMIZE_MODE_SWITCHING' should return nonzero for any ENTITY that - needs mode-switching. If you define this macro, you also have to - define 'NUM_MODES_FOR_MODE_SWITCHING', 'MODE_NEEDED', - 'MODE_PRIORITY_TO_MODE' and 'EMIT_MODE_SET'. 'MODE_AFTER', - 'MODE_ENTRY', and 'MODE_EXIT' are optional. - - -- Macro: NUM_MODES_FOR_MODE_SWITCHING - If you define '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 ... N - 1. N is used to specify that no - mode switch is needed / supplied. - - -- Macro: MODE_NEEDED (ENTITY, INSN) - ENTITY is an integer specifying a mode-switched entity. If - 'OPTIMIZE_MODE_SWITCHING' is defined, you must define this macro to - return an integer value not larger than the corresponding element - in 'NUM_MODES_FOR_MODE_SWITCHING', to denote the mode that ENTITY - must be switched into prior to the execution of INSN. - - -- Macro: MODE_AFTER (ENTITY, MODE, INSN) - ENTITY is an integer specifying a mode-switched entity. If this - macro is defined, it is evaluated for every INSN during mode - switching. It determines the mode that an insn results in (if - different from the incoming mode). - - -- Macro: MODE_ENTRY (ENTITY) - If this macro is defined, it is evaluated for every ENTITY that - needs mode switching. It should evaluate to an integer, which is a - mode that ENTITY is assumed to be switched to at function entry. - If 'MODE_ENTRY' is defined then 'MODE_EXIT' must be defined. - - -- Macro: MODE_EXIT (ENTITY) - If this macro is defined, it is evaluated for every ENTITY that - needs mode switching. It should evaluate to an integer, which is a - mode that ENTITY is assumed to be switched to at function exit. If - 'MODE_EXIT' is defined then 'MODE_ENTRY' must be defined. - - -- Macro: MODE_PRIORITY_TO_MODE (ENTITY, N) - This macro specifies the order in which modes for ENTITY are - processed. 0 is the highest priority, - 'NUM_MODES_FOR_MODE_SWITCHING[ENTITY] - 1' the lowest. The value - of the macro should be an integer designating a mode for ENTITY. - For any fixed ENTITY, 'mode_priority_to_mode' (ENTITY, N) shall be - a bijection in 0 ... 'num_modes_for_mode_switching[ENTITY] - 1'. - - -- Macro: EMIT_MODE_SET (ENTITY, MODE, HARD_REGS_LIVE) - Generate one or more insns to set ENTITY to MODE. HARD_REG_LIVE is - the set of hard registers live at the point where the insn(s) are - to be inserted. - - -File: gccint.info, Node: Target Attributes, Next: Emulated TLS, Prev: Mode Switching, Up: Target Macros - -17.25 Defining target-specific uses of '__attribute__' -====================================================== - -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 'extend.texi'. - - -- Target Hook: const struct attribute_spec * TARGET_ATTRIBUTE_TABLE - If defined, this target hook points to an array of 'struct - attribute_spec' (defined in '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. - - -- Target Hook: bool TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P (const_tree - NAME) - If defined, this target hook is a function which returns true if - the machine-specific attribute named NAME expects an identifier - given as its first argument to be passed on as a plain identifier, - not subjected to name lookup. If this is not defined, the default - is false for all machine-specific attributes. - - -- Target Hook: int TARGET_COMP_TYPE_ATTRIBUTES (const_tree TYPE1, - const_tree TYPE2) - If defined, this target hook is a function which returns zero if - the attributes on TYPE1 and 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. - - -- Target Hook: void TARGET_SET_DEFAULT_TYPE_ATTRIBUTES (tree TYPE) - If defined, this target hook is a function which assigns default - attributes to the newly defined TYPE. - - -- Target Hook: tree TARGET_MERGE_TYPE_ATTRIBUTES (tree TYPE1, tree - TYPE2) - Define this target hook if the merging of type attributes needs - special handling. If defined, the result is a list of the combined - 'TYPE_ATTRIBUTES' of TYPE1 and TYPE2. It is assumed that - 'comptypes' has already been called and returned 1. This function - may call 'merge_attributes' to handle machine-independent merging. - - -- Target Hook: tree TARGET_MERGE_DECL_ATTRIBUTES (tree OLDDECL, tree - NEWDECL) - Define this target hook if the merging of decl attributes needs - special handling. If defined, the result is a list of the combined - 'DECL_ATTRIBUTES' of OLDDECL and NEWDECL. NEWDECL is a duplicate - declaration of 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 - 'merge_attributes' to handle machine-independent merging. - - If the only target-specific handling you require is 'dllimport' for - Microsoft Windows targets, you should define the macro - 'TARGET_DLLIMPORT_DECL_ATTRIBUTES' to '1'. The compiler will then - define a function called 'merge_dllimport_decl_attributes' which - can then be defined as the expansion of - 'TARGET_MERGE_DECL_ATTRIBUTES'. You can also add - 'handle_dll_attribute' in the attribute table for your port to - perform initial processing of the 'dllimport' and 'dllexport' - attributes. This is done in 'i386/cygwin.h' and 'i386/i386.c', for - example. - - -- Target Hook: bool TARGET_VALID_DLLIMPORT_ATTRIBUTE_P (const_tree - DECL) - DECL is a variable or function with '__attribute__((dllimport))' - specified. Use this hook if the target needs to add extra - validation checks to 'handle_dll_attribute'. - - -- Macro: TARGET_DECLSPEC - Define this macro to a nonzero value if you want to treat - '__declspec(X)' as equivalent to '__attribute((X))'. By default, - this behavior is enabled only for targets that define - 'TARGET_DLLIMPORT_DECL_ATTRIBUTES'. The current implementation of - '__declspec' is via a built-in macro, but you should not rely on - this implementation detail. - - -- Target Hook: void TARGET_INSERT_ATTRIBUTES (tree NODE, tree - *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 NODE argument is the decl - which is being created. The 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 '*ATTR_PTR' modified to - point to the new attributes, or a copy of the list may be made if - further changes are needed. - - -- Target Hook: bool TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P (const_tree - FNDECL) - This target hook returns 'true' if it is OK to inline FNDECL into - the current function, despite its having target-specific - attributes, 'false' otherwise. By default, if a function has a - target specific attribute attached to it, it will not be inlined. - - -- Target Hook: bool TARGET_OPTION_VALID_ATTRIBUTE_P (tree FNDECL, tree - NAME, tree ARGS, int FLAGS) - This hook is called to parse 'attribute(target("..."))', which - allows setting target-specific options on individual functions. - These function-specific options may differ from the options - specified on the command line. The hook should return 'true' if - the options are valid. - - The hook should set the 'DECL_FUNCTION_SPECIFIC_TARGET' field in - the function declaration to hold a pointer to a target-specific - 'struct cl_target_option' structure. - - -- Target Hook: void TARGET_OPTION_SAVE (struct cl_target_option *PTR, - struct gcc_options *OPTS) - This hook is called to save any additional target-specific - information in the 'struct cl_target_option' structure for - function-specific options from the 'struct gcc_options' structure. - *Note Option file format::. - - -- Target Hook: void TARGET_OPTION_RESTORE (struct gcc_options *OPTS, - struct cl_target_option *PTR) - This hook is called to restore any additional target-specific - information in the 'struct cl_target_option' structure for - function-specific options to the 'struct gcc_options' structure. - - -- Target Hook: void TARGET_OPTION_PRINT (FILE *FILE, int INDENT, - struct cl_target_option *PTR) - This hook is called to print any additional target-specific - information in the 'struct cl_target_option' structure for - function-specific options. - - -- Target Hook: bool TARGET_OPTION_PRAGMA_PARSE (tree ARGS, tree - POP_TARGET) - This target hook parses the options for '#pragma GCC target', which - sets the target-specific options for functions that occur later in - the input stream. The options accepted should be the same as those - handled by the 'TARGET_OPTION_VALID_ATTRIBUTE_P' hook. - - -- Target Hook: void TARGET_OPTION_OVERRIDE (void) - Sometimes certain combinations of command options do not make sense - on a particular target machine. You can override the hook - 'TARGET_OPTION_OVERRIDE' to take account of this. This hooks is - called once just after all the command options have been parsed. - - Don't use this hook to turn on various extra optimizations for - '-O'. That is what 'TARGET_OPTION_OPTIMIZATION' is for. - - If you need to do something whenever the optimization level is - changed via the optimize attribute or pragma, see - 'TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE' - - -- Target Hook: bool TARGET_OPTION_FUNCTION_VERSIONS (tree DECL1, tree - DECL2) - This target hook returns 'true' if DECL1 and DECL2 are versions of - the same function. DECL1 and DECL2 are function versions if and - only if they have the same function signature and different target - specific attributes, that is, they are compiled for different - target machines. - - -- Target Hook: bool TARGET_CAN_INLINE_P (tree CALLER, tree CALLEE) - This target hook returns 'false' if the CALLER function cannot - inline CALLEE, based on target specific information. By default, - inlining is not allowed if the callee function has function - specific target options and the caller does not use the same - options. - - -File: gccint.info, Node: Emulated TLS, Next: MIPS Coprocessors, Prev: Target Attributes, Up: Target Macros - -17.26 Emulating TLS -=================== - -For targets whose psABI does not provide Thread Local Storage via -specific relocations and instruction sequences, an emulation layer is -used. A set of target hooks allows this emulation layer to be -configured for the requirements of a particular target. For instance -the psABI may in fact specify TLS support in terms of an emulation -layer. - - The emulation layer works by creating a control object for every TLS -object. To access the TLS object, a lookup function is provided which, -when given the address of the control object, will return the address of -the current thread's instance of the TLS object. - - -- Target Hook: const char * TARGET_EMUTLS_GET_ADDRESS - Contains the name of the helper function that uses a TLS control - object to locate a TLS instance. The default causes libgcc's - emulated TLS helper function to be used. - - -- Target Hook: const char * TARGET_EMUTLS_REGISTER_COMMON - Contains the name of the helper function that should be used at - program startup to register TLS objects that are implicitly - initialized to zero. If this is 'NULL', all TLS objects will have - explicit initializers. The default causes libgcc's emulated TLS - registration function to be used. - - -- Target Hook: const char * TARGET_EMUTLS_VAR_SECTION - Contains the name of the section in which TLS control variables - should be placed. The default of 'NULL' allows these to be placed - in any section. - - -- Target Hook: const char * TARGET_EMUTLS_TMPL_SECTION - Contains the name of the section in which TLS initializers should - be placed. The default of 'NULL' allows these to be placed in any - section. - - -- Target Hook: const char * TARGET_EMUTLS_VAR_PREFIX - Contains the prefix to be prepended to TLS control variable names. - The default of 'NULL' uses a target-specific prefix. - - -- Target Hook: const char * TARGET_EMUTLS_TMPL_PREFIX - Contains the prefix to be prepended to TLS initializer objects. - The default of 'NULL' uses a target-specific prefix. - - -- Target Hook: tree TARGET_EMUTLS_VAR_FIELDS (tree TYPE, tree *NAME) - Specifies a function that generates the FIELD_DECLs for a TLS - control object type. TYPE is the RECORD_TYPE the fields are for - and NAME should be filled with the structure tag, if the default of - '__emutls_object' is unsuitable. The default creates a type - suitable for libgcc's emulated TLS function. - - -- Target Hook: tree TARGET_EMUTLS_VAR_INIT (tree VAR, tree DECL, tree - TMPL_ADDR) - Specifies a function that generates the CONSTRUCTOR to initialize a - TLS control object. VAR is the TLS control object, DECL is the TLS - object and TMPL_ADDR is the address of the initializer. The - default initializes libgcc's emulated TLS control object. - - -- Target Hook: bool TARGET_EMUTLS_VAR_ALIGN_FIXED - Specifies whether the alignment of TLS control variable objects is - fixed and should not be increased as some backends may do to - optimize single objects. The default is false. - - -- Target Hook: bool TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS - Specifies whether a DWARF 'DW_OP_form_tls_address' location - descriptor may be used to describe emulated TLS control objects. - - -File: gccint.info, Node: MIPS Coprocessors, Next: PCH Target, Prev: Emulated TLS, Up: Target Macros - -17.27 Defining coprocessor specifics for MIPS targets. -====================================================== - -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: - - register unsigned int cp0count asm ("c0r1"); - unsigned int d; - - d = cp0count + 3; - - ("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 '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. - - -File: gccint.info, Node: PCH Target, Next: C++ ABI, Prev: MIPS Coprocessors, Up: Target Macros - -17.28 Parameters for Precompiled Header Validity Checking -========================================================= - - -- Target Hook: void * TARGET_GET_PCH_VALIDITY (size_t *SZ) - This hook returns a pointer to the data needed by - 'TARGET_PCH_VALID_P' and sets '*SZ' to the size of the data in - bytes. - - -- Target Hook: const char * TARGET_PCH_VALID_P (const void *DATA, - size_t SZ) - This hook checks whether the options used to create a PCH file are - compatible with the current settings. It returns 'NULL' if so and - a suitable error message if not. Error messages will be presented - to the user and must be localized using '_(MSG)'. - - DATA is the data that was returned by 'TARGET_GET_PCH_VALIDITY' - when the PCH file was created and 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 'default_pch_valid_p' should be suitable - for most targets. - - -- Target Hook: const char * TARGET_CHECK_PCH_TARGET_FLAGS (int - PCH_FLAGS) - If this hook is nonnull, the default implementation of - 'TARGET_PCH_VALID_P' will use it to check for compatible values of - 'target_flags'. PCH_FLAGS specifies the value that 'target_flags' - had when the PCH file was created. The return value is the same as - for 'TARGET_PCH_VALID_P'. - - -- Target Hook: void TARGET_PREPARE_PCH_SAVE (void) - Called before writing out a PCH file. If the target has some - garbage-collected data that needs to be in a particular state on - PCH loads, it can use this hook to enforce that state. Very few - targets need to do anything here. - - -File: gccint.info, Node: C++ ABI, Next: Named Address Spaces, Prev: PCH Target, Up: Target Macros - -17.29 C++ ABI parameters -======================== - - -- 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. - - -- Target Hook: bool TARGET_CXX_GUARD_MASK_BIT (void) - This hook determines how guard variables are used. It should - return 'false' (the default) if the first byte should be used. A - return value of 'true' indicates that only the least significant - bit should be used. - - -- Target Hook: tree TARGET_CXX_GET_COOKIE_SIZE (tree TYPE) - This hook returns the size of the cookie to use when allocating an - array whose elements have the indicated TYPE. Assumes that it is - already known that a cookie is needed. The default is 'max(sizeof - (size_t), alignof(type))', as defined in section 2.7 of the - IA64/Generic C++ ABI. - - -- Target Hook: bool TARGET_CXX_COOKIE_HAS_SIZE (void) - This hook should return 'true' if the element size should be stored - in array cookies. The default is to return 'false'. - - -- Target Hook: int TARGET_CXX_IMPORT_EXPORT_CLASS (tree TYPE, int - IMPORT_EXPORT) - If defined by a backend this hook allows the decision made to - export class TYPE to be overruled. Upon entry IMPORT_EXPORT will - contain 1 if the class is going to be exported, -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. - - -- Target Hook: bool TARGET_CXX_CDTOR_RETURNS_THIS (void) - This hook should return 'true' if constructors and destructors - return the address of the object created/destroyed. The default is - to return 'false'. - - -- 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 - 'true'. - - -- Target Hook: void TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY (tree - DECL) - 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 'DECL_VISIBILITY' and 'DECL_VISIBILITY_SPECIFIED'. - - -- 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. - - -- 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. - - -- Target Hook: bool TARGET_CXX_USE_AEABI_ATEXIT (void) - This hook returns true if '__aeabi_atexit' (as defined by the ARM - EABI) should be used to register static destructors when - '-fuse-cxa-atexit' is in effect. The default is to return false to - use '__cxa_atexit'. - - -- Target Hook: bool TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT (void) - This hook returns true if the target 'atexit' function can be used - in the same manner as '__cxa_atexit' to register C++ static - destructors. This requires that 'atexit'-registered functions in - shared libraries are run in the correct order when the libraries - are unloaded. The default is to return false. - - -- Target Hook: void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree TYPE) - 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). - - -- Target Hook: tree TARGET_CXX_DECL_MANGLING_CONTEXT (const_tree DECL) - Return target-specific mangling context of DECL or 'NULL_TREE'. - - -File: gccint.info, Node: Named Address Spaces, Next: Misc, Prev: C++ ABI, Up: Target Macros - -17.30 Adding support for named address spaces -============================================= - -The draft technical report of the ISO/IEC JTC1 S22 WG14 N1275 standards -committee, 'Programming Languages - C - Extensions to support embedded -processors', specifies a syntax for embedded processors to specify -alternate address spaces. You can configure a GCC port to support -section 5.1 of the draft report to add support for address spaces other -than the default address space. These address spaces are new keywords -that are similar to the 'volatile' and 'const' type attributes. - - Pointers to named address spaces can have a different size than -pointers to the generic address space. - - For example, the SPU port uses the '__ea' address space to refer to -memory in the host processor, rather than memory local to the SPU -processor. Access to memory in the '__ea' address space involves -issuing DMA operations to move data between the host processor and the -local processor memory address space. Pointers in the '__ea' address -space are either 32 bits or 64 bits based on the '-mea32' or '-mea64' -switches (native SPU pointers are always 32 bits). - - Internally, address spaces are represented as a small integer in the -range 0 to 15 with address space 0 being reserved for the generic -address space. - - To register a named address space qualifier keyword with the C front -end, the target may call the 'c_register_addr_space' routine. For -example, the SPU port uses the following to declare '__ea' as the -keyword for named address space #1: - #define ADDR_SPACE_EA 1 - c_register_addr_space ("__ea", ADDR_SPACE_EA); - - -- Target Hook: enum machine_mode TARGET_ADDR_SPACE_POINTER_MODE - (addr_space_t ADDRESS_SPACE) - Define this to return the machine mode to use for pointers to - ADDRESS_SPACE if the target supports named address spaces. The - default version of this hook returns 'ptr_mode' for the generic - address space only. - - -- Target Hook: enum machine_mode TARGET_ADDR_SPACE_ADDRESS_MODE - (addr_space_t ADDRESS_SPACE) - Define this to return the machine mode to use for addresses in - ADDRESS_SPACE if the target supports named address spaces. The - default version of this hook returns 'Pmode' for the generic - address space only. - - -- Target Hook: bool TARGET_ADDR_SPACE_VALID_POINTER_MODE (enum - machine_mode MODE, addr_space_t AS) - Define this to return nonzero if the port can handle pointers with - machine mode MODE to address space AS. This target hook is the - same as the 'TARGET_VALID_POINTER_MODE' target hook, except that it - includes explicit named address space support. The default version - of this hook returns true for the modes returned by either the - 'TARGET_ADDR_SPACE_POINTER_MODE' or - 'TARGET_ADDR_SPACE_ADDRESS_MODE' target hooks for the given address - space. - - -- Target Hook: bool TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P (enum - machine_mode MODE, rtx EXP, bool STRICT, addr_space_t AS) - Define this to return true if EXP is a valid address for mode MODE - in the named address space AS. The STRICT parameter says whether - strict addressing is in effect after reload has finished. This - target hook is the same as the 'TARGET_LEGITIMATE_ADDRESS_P' target - hook, except that it includes explicit named address space support. - - -- Target Hook: rtx TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS (rtx X, rtx - OLDX, enum machine_mode MODE, addr_space_t AS) - Define this to modify an invalid address X to be a valid address - with mode MODE in the named address space AS. This target hook is - the same as the 'TARGET_LEGITIMIZE_ADDRESS' target hook, except - that it includes explicit named address space support. - - -- Target Hook: bool TARGET_ADDR_SPACE_SUBSET_P (addr_space_t SUBSET, - addr_space_t SUPERSET) - Define this to return whether the SUBSET named address space is - contained within the SUPERSET named address space. Pointers to a - named address space that is a subset of another named address space - will be converted automatically without a cast if used together in - arithmetic operations. Pointers to a superset address space can be - converted to pointers to a subset address space via explicit casts. - - -- Target Hook: rtx TARGET_ADDR_SPACE_CONVERT (rtx OP, tree FROM_TYPE, - tree TO_TYPE) - Define this to convert the pointer expression represented by the - RTL OP with type FROM_TYPE that points to a named address space to - a new pointer expression with type TO_TYPE that points to a - different named address space. When this hook it called, it is - guaranteed that one of the two address spaces is a subset of the - other, as determined by the 'TARGET_ADDR_SPACE_SUBSET_P' target - hook. - - -File: gccint.info, Node: Misc, Prev: Named Address Spaces, Up: Target Macros - -17.31 Miscellaneous Parameters -============================== - -Here are several miscellaneous parameters. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: CASE_VECTOR_MODE - An alias for a machine mode name. This is the machine mode that - elements of a jump-table should have. - - -- Macro: CASE_VECTOR_SHORTEN_MODE (MIN_OFFSET, MAX_OFFSET, BODY) - Optional: return the preferred mode for an '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 - 'addr_diff_vec'. To make this work, you also have to define - 'INSN_ALIGN' and make the alignment for 'addr_diff_vec' explicit. - The BODY argument is provided so that the offset_unsigned and scale - flags can be updated. - - -- Macro: 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 '-fPIC' or '-fPIC' is - in effect. - - -- Target Hook: unsigned int TARGET_CASE_VALUES_THRESHOLD (void) - This function return 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 - 'casesi' instruction and five otherwise. This is best for most - machines. - - -- Macro: 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. - - -- Macro: LOAD_EXTEND_OP (MEM_MODE) - Define this macro to be a C expression indicating when insns that - read memory in MEM_MODE, an integral mode narrower than a word, set - the bits outside of MEM_MODE to be either the sign-extension or the - zero-extension of the data read. Return 'SIGN_EXTEND' for values - of MEM_MODE for which the insn sign-extends, 'ZERO_EXTEND' for - which it zero-extends, and 'UNKNOWN' for other modes. - - This macro is not called with MEM_MODE non-integral or with a width - greater than or equal to 'BITS_PER_WORD', so you may return any - value in this case. Do not define this macro if it would always - return 'UNKNOWN'. On machines where this macro is defined, you - will normally define it as the constant 'SIGN_EXTEND' or - 'ZERO_EXTEND'. - - You may return a non-'UNKNOWN' value even if for some hard - registers the sign extension is not performed, if for the - 'REGNO_REG_CLASS' of these hard registers - 'CANNOT_CHANGE_MODE_CLASS' returns nonzero when the FROM mode is - MEM_MODE and the TO mode is any integral mode larger than this but - not larger than 'word_mode'. - - You must return 'UNKNOWN' if for some hard registers that allow - this mode, 'CANNOT_CHANGE_MODE_CLASS' says that they cannot change - to 'word_mode', but that they can change to another integral mode - that is larger then MEM_MODE but still smaller than 'word_mode'. - - -- Macro: SHORT_IMMEDIATES_SIGN_EXTEND - Define this macro if loading short immediate values into registers - sign extends. - - -- Target Hook: unsigned int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum - machine_mode MODE) - When '-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 MODE. The default implementation returns 3 - if the machine has an instruction for the division, and 2 if it - does not. - - -- Macro: MOVE_MAX - The maximum number of bytes that a single instruction can move - quickly between memory and registers or between two memory - locations. - - -- Macro: 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 'MOVE_MAX'. - Otherwise, it is the constant value that is the largest value that - 'MOVE_MAX' can have at run-time. - - -- Macro: 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 '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 'SHIFT_COUNT_TRUNCATED' to - be zero on such machines. Instead, add patterns to the '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. - - -- Target Hook: unsigned HOST_WIDE_INT TARGET_SHIFT_TRUNCATION_MASK - (enum machine_mode MODE) - This function describes how the standard shift patterns for MODE - deal with shifts by negative amounts or by more than the width of - the mode. *Note shift patterns::. - - On many machines, the shift patterns will apply a mask M to the - shift count, meaning that a fixed-width shift of X by Y is - equivalent to an arbitrary-width shift of X by Y & M. If this is - true for mode MODE, the function should return M, otherwise it - should return 0. A return value of 0 indicates that no particular - behavior is guaranteed. - - Note that, unlike 'SHIFT_COUNT_TRUNCATED', this function does _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 - 'GET_MODE_BITSIZE (MODE) - 1' if 'SHIFT_COUNT_TRUNCATED' and 0 - otherwise. This definition is always safe, but if - 'SHIFT_COUNT_TRUNCATED' is false, and some shift patterns - nevertheless truncate the shift count, you may get better code by - overriding it. - - -- Macro: TRULY_NOOP_TRUNCATION (OUTPREC, INPREC) - A C expression which is nonzero if on this machine it is safe to - "convert" an integer of INPREC bits to one of OUTPREC bits (where - OUTPREC is smaller than INPREC) by merely operating on it as if it - had only OUTPREC bits. - - On many machines, this expression can be 1. - - When 'TRULY_NOOP_TRUNCATION' returns 1 for a pair of sizes for - modes for which 'MODES_TIEABLE_P' is 0, suboptimal code can result. - If this is the case, making 'TRULY_NOOP_TRUNCATION' return 0 in - such cases may improve things. - - -- Target Hook: int TARGET_MODE_REP_EXTENDED (enum machine_mode MODE, - enum machine_mode REP_MODE) - The representation of an integral mode can be such that the values - are always extended to a wider integral mode. Return 'SIGN_EXTEND' - if values of MODE are represented in sign-extended form to - REP_MODE. Return 'UNKNOWN' otherwise. (Currently, none of the - targets use zero-extended representation this way so unlike - 'LOAD_EXTEND_OP', 'TARGET_MODE_REP_EXTENDED' is expected to return - either 'SIGN_EXTEND' or 'UNKNOWN'. Also no target extends MODE to - REP_MODE so that REP_MODE is not the next widest integral mode and - currently we take advantage of this fact.) - - Similarly to 'LOAD_EXTEND_OP' you may return a non-'UNKNOWN' value - even if the extension is not performed on certain hard registers as - long as for the 'REGNO_REG_CLASS' of these hard registers - 'CANNOT_CHANGE_MODE_CLASS' returns nonzero. - - Note that 'TARGET_MODE_REP_EXTENDED' and 'LOAD_EXTEND_OP' describe - two related properties. If you define 'TARGET_MODE_REP_EXTENDED - (mode, word_mode)' you probably also want to define 'LOAD_EXTEND_OP - (mode)' to return the same type of extension. - - In order to enforce the representation of 'mode', - 'TRULY_NOOP_TRUNCATION' should return false when truncating to - 'mode'. - - -- Macro: 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 ('cstoreMODE4') when the condition is true. This - description must apply to _all_ the 'cstoreMODE4' patterns and all - the comparison operators whose results have a 'MODE_INT' mode. - - A value of 1 or -1 means that the instruction implementing the - comparison operator returns exactly 1 or -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 'cstoreMODE4' pattern. Either the low bit or the - sign bit of 'STORE_FLAG_VALUE' be on. Presently, only those bits - are used by the compiler. - - If 'STORE_FLAG_VALUE' is neither 1 or -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 'SImode' value and where 'STORE_FLAG_VALUE' is defined as - '0x80000000', saying that just the sign bit is relevant, the - expression - - (ne:SI (and:SI X (const_int POWER-OF-2)) (const_int 0)) - - can be converted to - - (ashift:SI X (const_int N)) - - where 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 - <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 'STORE_FLAG_VALUE', and hence the - instructions to be used: - - * Use the shortest sequence that yields a valid definition for - '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. - - * For equal-length sequences, use a value of 1 or -1, with -1 - being slightly preferred on machines with expensive jumps and - 1 preferred on other machines. - - * As a second choice, choose a value of '0x80000001' if - instructions exist that set both the sign and low-order bits - but do not define the others. - - * Otherwise, use a value of '0x80000000'. - - Many machines can produce both the value chosen for - '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 - - (set A (neg:M (ne:M B C))) - - Some machines can also perform 'and' or 'plus' operations on - condition code values with less instructions than the corresponding - 'cstoreMODE4' insn followed by 'and' or 'plus'. On those machines, - define the appropriate patterns. Use the names 'incscc' and - 'decscc', respectively, for the patterns which perform 'plus' or - 'minus' operations on condition code values. See 'rs6000.md' for - some examples. The GNU Superoptimizer 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 'STORE_FLAG_VALUE' if the machine has no store-flag - instructions, or if the value generated by these instructions is 1. - - -- Macro: FLOAT_STORE_FLAG_VALUE (MODE) - A C expression that gives a nonzero '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. - - -- Macro: VECTOR_STORE_FLAG_VALUE (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 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 'const1_rtx' or 'constm1_rtx'. This macro may return - 'NULL_RTX' to prevent the compiler optimizing such vector - comparison operations for the given mode. - - -- Macro: CLZ_DEFINED_VALUE_AT_ZERO (MODE, VALUE) - -- Macro: CTZ_DEFINED_VALUE_AT_ZERO (MODE, VALUE) - A C expression that indicates whether the architecture defines a - value for 'clz' or 'ctz' with a zero operand. A result of '0' - indicates the value is undefined. If the value is defined for only - the RTL expression, the macro should evaluate to '1'; if the value - applies also to the corresponding optab entry (which is normally - the case if it expands directly into the corresponding RTL), then - the macro should evaluate to '2'. In the cases where the value is - defined, VALUE should be set to this value. - - If this macro is not defined, the value of 'clz' or 'ctz' at zero - is assumed to be undefined. - - This macro must be defined if the target's expansion for '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, and to provide a default expansion for the 'ffs' optab. - - Note that regardless of this macro the "definedness" of 'clz' and - 'ctz' at zero do _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. - - -- Macro: 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; 'SImode' on 32-bit machine or 'DImode' on 64-bit - machines. On some machines you must define this to be one of the - partial integer modes, such as 'PSImode'. - - The width of 'Pmode' must be at least as large as the value of - 'POINTER_SIZE'. If it is not equal, you must define the macro - 'POINTERS_EXTEND_UNSIGNED' to specify how pointers are extended to - 'Pmode'. - - -- Macro: FUNCTION_MODE - An alias for the machine mode used for memory references to - functions being called, in 'call' RTL expressions. On most CISC - machines, where an instruction can begin at any byte address, this - should be 'QImode'. On most RISC machines, where all instructions - have fixed size and alignment, this should be a mode with the same - size and alignment as the machine instruction words - typically - 'SImode' or 'HImode'. - - -- Macro: STDC_0_IN_SYSTEM_HEADERS - In normal operation, the preprocessor expands '__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 '__STDC__' is normally 0, but is 1 if the user - specifies strict conformance to the C Standard. - - Defining 'STDC_0_IN_SYSTEM_HEADERS' makes GNU CPP follows the host - convention when processing system header files, but when processing - user files '__STDC__' will always expand to 1. - - -- C Target Hook: const char * TARGET_C_PREINCLUDE (void) - Define this hook to return the name of a header file to be included - at the start of all compilations, as if it had been included with - '#include <FILE>'. If this hook returns 'NULL', or is not defined, - or the header is not found, or if the user specifies - '-ffreestanding' or '-nostdinc', no header is included. - - This hook can be used together with a header provided by the system - C library to implement ISO C requirements for certain macros to be - predefined that describe properties of the whole implementation - rather than just the compiler. - - -- C Target Hook: bool TARGET_CXX_IMPLICIT_EXTERN_C (const char*) - Define this hook to add target-specific C++ implicit extern C - functions. If this function returns true for the name of a - file-scope function, that function implicitly gets extern "C" - linkage rather than whatever language linkage the declaration would - normally have. An example of such function is WinMain on Win32 - targets. - - -- Macro: 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 'extern "C" {...}'. - - -- Macro: 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 'c_register_pragma' or '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 'TARGET_INSERT_ATTRIBUTES' as - well. - - Preprocessor macros that appear on pragma lines are not expanded. - All '#pragma' directives that do not match any registered pragma - are silently ignored, unless the user specifies - '-Wunknown-pragmas'. - - -- Function: void c_register_pragma (const char *SPACE, const char - *NAME, void (*CALLBACK) (struct cpp_reader *)) - -- Function: void c_register_pragma_with_expansion (const char *SPACE, - const char *NAME, void (*CALLBACK) (struct cpp_reader *)) - - Each call to 'c_register_pragma' or - 'c_register_pragma_with_expansion' establishes one pragma. The - CALLBACK routine will be called when the preprocessor encounters a - pragma of the form - - #pragma [SPACE] NAME ... - - SPACE is the case-sensitive namespace of the pragma, or 'NULL' to - put the pragma in the global namespace. The callback routine - receives PFILE as its first argument, which can be passed on to - cpplib's functions if necessary. You can lex tokens after the NAME - by calling '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 'CPP_EOF'. Macro expansion occurs on the arguments - of pragmas registered with 'c_register_pragma_with_expansion' but - not on the arguments of pragmas registered with - 'c_register_pragma'. - - Note that the use of '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 '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 'c_target_objs' and 'cxx_target_objs' in the - target entry in the 'config.gcc' file. These variables should name - the target-specific, language-specific object file which contains - the code that uses 'pragma_lex'. Note it will also be necessary to - add a rule to the makefile fragment pointed to by 'tmake_file' that - shows how to build this object file. - - -- Macro: HANDLE_PRAGMA_PACK_WITH_EXPANSION - Define this macro if macros should be expanded in the arguments of - '#pragma pack'. - - -- Macro: 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 '#pragma pack()' (that is, a small power of two). - - -- Macro: DOLLARS_IN_IDENTIFIERS - Define this macro to control use of the character '$' in identifier - names for the C family of languages. 0 means '$' 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. - - -- Macro: INSN_SETS_ARE_DELAYED (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 INSN, even if they appear to use a resource set or - clobbered in INSN. INSN is always a 'jump_insn' or an 'insn'; GCC - knows that every 'call_insn' has this behavior. On machines where - some 'insn' or '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. - - -- Macro: INSN_REFERENCES_ARE_DELAYED (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 INSN, even if they appear to set or clobber a resource - referenced in INSN. INSN is always a 'jump_insn' or an 'insn'. On - machines where some 'insn' or '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 INSN. - - You need not define this macro if it would always return zero. - - -- Macro: 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. - - -- Target Hook: tree TARGET_MD_ASM_CLOBBERS (tree OUTPUTS, tree INPUTS, - tree CLOBBERS) - This target hook should add to CLOBBERS 'STRING_CST' trees for any - hard regs the port wishes to automatically clobber for an asm. It - should return the result of the last 'tree_cons' used to add a - clobber. The OUTPUTS, INPUTS and 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 'tree_overlaps_hard_reg_set', declared in 'tree.h', to test - for overlap with regards to asm-declared registers. - - -- Macro: MATH_LIBRARY - Define this macro as a C string constant for the linker argument to - link in the system math library, minus the initial '"-l"', or '""' - if the target does not have a separate math library. - - You need only define this macro if the default of '"m"' is wrong. - - -- Macro: 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 '"LIBRARY_PATH"' - is wrong. - - -- Macro: 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 '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. - - -- Macro: 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 'BRANCH_COST'+1 is the default if the machine does not use - cc0, and 1 if it does use cc0. - - -- Macro: IFCVT_MODIFY_TESTS (CE_INFO, TRUE_EXPR, FALSE_EXPR) - Used if the target needs to perform machine-dependent modifications - on the conditionals used for turning basic blocks into - conditionally executed code. CE_INFO points to a data structure, - 'struct ce_if_block', which contains information about the - currently processed blocks. TRUE_EXPR and FALSE_EXPR are the tests - that are used for converting the then-block and the else-block, - respectively. Set either TRUE_EXPR or FALSE_EXPR to a null pointer - if the tests cannot be converted. - - -- Macro: IFCVT_MODIFY_MULTIPLE_TESTS (CE_INFO, BB, TRUE_EXPR, - FALSE_EXPR) - Like 'IFCVT_MODIFY_TESTS', but used when converting more - complicated if-statements into conditions combined by 'and' and - 'or' operations. BB contains the basic block that contains the - test that is currently being processed and about to be turned into - a condition. - - -- Macro: IFCVT_MODIFY_INSN (CE_INFO, PATTERN, INSN) - A C expression to modify the PATTERN of an INSN that is to be - converted to conditional execution format. CE_INFO points to a - data structure, 'struct ce_if_block', which contains information - about the currently processed blocks. - - -- Macro: IFCVT_MODIFY_FINAL (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 'struct ce_if_block' structure that is - pointed to by CE_INFO. - - -- Macro: IFCVT_MODIFY_CANCEL (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 'struct ce_if_block' structure that is - pointed to by CE_INFO. - - -- Macro: IFCVT_MACHDEP_INIT (CE_INFO) - A C expression to initialize any machine specific data for - if-conversion of the if-block in the 'struct ce_if_block' structure - that is pointed to by CE_INFO. - - -- Target Hook: void TARGET_MACHINE_DEPENDENT_REORG (void) - 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. - - -- Target Hook: void TARGET_INIT_BUILTINS (void) - 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 - 'lang_hooks.builtin_function' which is defined by the language - front end. You can use any type nodes set up by - 'build_common_tree_nodes'; only language front ends that use those - two functions will call 'TARGET_INIT_BUILTINS'. - - -- Target Hook: tree TARGET_BUILTIN_DECL (unsigned CODE, bool - INITIALIZE_P) - Define this hook if you have any machine-specific built-in - functions that need to be defined. It should be a function that - returns the builtin function declaration for the builtin function - code CODE. If there is no such builtin and it cannot be - initialized at this time if INITIALIZE_P is true the function - should return 'NULL_TREE'. If CODE is out of range the function - should return 'error_mark_node'. - - -- Target Hook: rtx TARGET_EXPAND_BUILTIN (tree EXP, rtx TARGET, rtx - SUBTARGET, enum machine_mode MODE, int IGNORE) - - Expand a call to a machine specific built-in function that was set - up by 'TARGET_INIT_BUILTINS'. EXP is the expression for the - function call; the result should go to TARGET if that is - convenient, and have mode MODE if that is convenient. SUBTARGET - may be used as the target for computing one of EXP's operands. - IGNORE is nonzero if the value is to be ignored. This function - should return the result of the call to the built-in function. - - -- Target Hook: tree TARGET_RESOLVE_OVERLOADED_BUILTIN (unsigned int - LOC, tree FNDECL, void *ARGLIST) - Select a replacement for a machine specific built-in function that - was set up by 'TARGET_INIT_BUILTINS'. This is done _before_ - regular type checking, and so allows the target to implement a - crude form of function overloading. FNDECL is the declaration of - the built-in function. ARGLIST is the list of arguments passed to - the built-in function. The result is a complete expression that - implements the operation, usually another 'CALL_EXPR'. ARGLIST - really has type 'VEC(tree,gc)*' - - -- Target Hook: tree TARGET_FOLD_BUILTIN (tree FNDECL, int N_ARGS, tree - *ARGP, bool IGNORE) - Fold a call to a machine specific built-in function that was set up - by 'TARGET_INIT_BUILTINS'. FNDECL is the declaration of the - built-in function. N_ARGS is the number of arguments passed to the - function; the arguments themselves are pointed to by ARGP. The - result is another tree, valid for both GIMPLE and GENERIC, - containing a simplified expression for the call's result. If - IGNORE is true the value will be ignored. - - -- Target Hook: bool TARGET_GIMPLE_FOLD_BUILTIN (gimple_stmt_iterator - *GSI) - Fold a call to a machine specific built-in function that was set up - by 'TARGET_INIT_BUILTINS'. GSI points to the gimple statement - holding the function call. Returns true if any change was made to - the GIMPLE stream. - - -- Target Hook: int TARGET_COMPARE_VERSION_PRIORITY (tree DECL1, tree - DECL2) - This hook is used to compare the target attributes in two functions - to determine which function's features get higher priority. This - is used during function multi-versioning to figure out the order in - which two versions must be dispatched. A function version with a - higher priority is checked for dispatching earlier. DECL1 and - DECL2 are the two function decls that will be compared. - - -- Target Hook: tree TARGET_GET_FUNCTION_VERSIONS_DISPATCHER (void - *DECL) - This hook is used to get the dispatcher function for a set of - function versions. The dispatcher function is called to invoke the - right function version at run-time. DECL is one version from a set - of semantically identical versions. - - -- Target Hook: tree TARGET_GENERATE_VERSION_DISPATCHER_BODY (void - *ARG) - This hook is used to generate the dispatcher logic to invoke the - right function version at run-time for a given set of function - versions. ARG points to the callgraph node of the dispatcher - function whose body must be generated. - - -- Target Hook: bool TARGET_CAN_USE_DOLOOP_P (double_int ITERATIONS, - double_int ITERATIONS_MAX, unsigned int LOOP_DEPTH, bool - ENTERED_AT_TOP) - Return true if it is possible to use low-overhead loops - ('doloop_end' and 'doloop_begin') for a particular loop. - ITERATIONS gives the exact number of iterations, or 0 if not known. - ITERATIONS_MAX gives the maximum number of iterations, or 0 if not - known. LOOP_DEPTH is the nesting depth of the loop, with 1 for - innermost loops, 2 for loops that contain innermost loops, and so - on. ENTERED_AT_TOP is true if the loop is only entered from the - top. - - This hook is only used if 'doloop_end' is available. The default - implementation returns true. You can use - 'can_use_doloop_if_innermost' if the loop must be the innermost, - and if there are no other restrictions. - - -- Target Hook: const char * TARGET_INVALID_WITHIN_DOLOOP (const_rtx - INSN) - - Take an instruction in INSN and return NULL if it is valid within a - low-overhead loop, otherwise return a string explaining 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. - - -- Target Hook: bool TARGET_LEGITIMATE_COMBINED_INSN (rtx INSN) - Take an instruction in INSN and return 'false' if the instruction - is not appropriate as a combination of two or more instructions. - The default is to accept all instructions. - - -- Macro: MD_CAN_REDIRECT_BRANCH (BRANCH1, BRANCH2) - - Take a branch insn in BRANCH1 and another in BRANCH2. Return true - if redirecting BRANCH1 to the destination of 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. - - -- Target Hook: bool TARGET_CAN_FOLLOW_JUMP (const_rtx FOLLOWER, - const_rtx FOLLOWEE) - FOLLOWER and FOLLOWEE are JUMP_INSN instructions; return true if - FOLLOWER may be modified to follow FOLLOWEE; false, if it can't. - For example, on some targets, certain kinds of branches can't be - made to follow through a hot/cold partitioning. - - -- Target Hook: bool TARGET_COMMUTATIVE_P (const_rtx X, int OUTER_CODE) - This target hook returns 'true' if X is considered to be - commutative. Usually, this is just COMMUTATIVE_P (X), but the HP - PA doesn't consider PLUS to be commutative inside a MEM. - OUTER_CODE is the rtx code of the enclosing rtl, if known, - otherwise it is UNKNOWN. - - -- Target Hook: rtx TARGET_ALLOCATE_INITIAL_VALUE (rtx 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. - '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 'get_func_hard_reg_initial_val' or - 'get_hard_reg_initial_val'. Possible values are 'NULL_RTX', if you - don't want to do any special allocation, a 'REG' rtx--that would - typically be the hard register itself, if it is known not to be - clobbered--or a 'MEM'. If you are returning a 'MEM', this is only - a hint for the allocator; it might decide to use another register - anyways. You may use 'current_function_is_leaf' or 'REG_N_SETS' in - the hook to determine if the hard register in question will not be - clobbered. The default value of this hook is 'NULL', which - disables any special allocation. - - -- Target Hook: int TARGET_UNSPEC_MAY_TRAP_P (const_rtx X, unsigned - FLAGS) - This target hook returns nonzero if X, an 'unspec' or - 'unspec_volatile' operation, might cause a trap. Targets can use - this hook to enhance precision of analysis for 'unspec' and - 'unspec_volatile' operations. You may call 'may_trap_p_1' to - analyze inner elements of X in which case FLAGS should be passed - along. - - -- Target Hook: void TARGET_SET_CURRENT_FUNCTION (tree DECL) - The compiler invokes this hook whenever it changes its current - function context ('cfun'). You can define this function if the - back end needs to perform any initialization or reset actions on a - per-function basis. For example, it may be used to implement - function attributes that affect register usage or code generation - patterns. The argument DECL is the declaration for the new - function context, and may be null to indicate that the compiler has - left a function context and is returning to processing at the top - level. The default hook function does nothing. - - GCC sets 'cfun' to a dummy function context during initialization - of some parts of the back end. The hook function is not invoked in - this situation; you need not worry about the hook being invoked - recursively, or when the back end is in a partially-initialized - state. 'cfun' might be 'NULL' to indicate processing at top level, - outside of any function scope. - - -- Macro: 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 '.o' as the suffix for object files. - - -- Macro: 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. - - -- Macro: COLLECT_EXPORT_LIST - If defined, '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 'main' and uses - export lists. - - -- Macro: MODIFY_JNI_METHOD_CALL (MDECL) - Define this macro to a C expression representing a variant of the - method call 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 'stdcall' calling convention and this macro is then - defined as this expression: - - build_type_attribute_variant (MDECL, - build_tree_list - (get_identifier ("stdcall"), - NULL)) - - -- Target Hook: bool TARGET_CANNOT_MODIFY_JUMPS_P (void) - This target hook returns '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: - - static bool - cannot_modify_jumps_past_reload_p () - { - return (reload_completed || reload_in_progress); - } - - -- Target Hook: reg_class_t 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. - - -- Target Hook: bool TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED (bool - 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 'TARGET_BRANCH_TARGET_REGISTER_CLASS' that - might need saving are saved. AFTER_PROLOGUE_EPILOGUE_GEN indicates - if prologues and epilogues have already been generated. Note, even - if you only return true when AFTER_PROLOGUE_EPILOGUE_GEN is false, - you still are likely to have to make special provisions in - 'INITIAL_ELIMINATION_OFFSET' to reserve space for caller-saved - target registers. - - -- Target Hook: bool TARGET_HAVE_CONDITIONAL_EXECUTION (void) - This target hook returns true if the target supports conditional - execution. This target hook is required only when the target has - several different modes and they have different conditional - execution capability, such as ARM. - - -- Target Hook: unsigned TARGET_LOOP_UNROLL_ADJUST (unsigned NUNROLL, - struct loop *LOOP) - This target hook returns a new value for the number of times LOOP - should be unrolled. The parameter NUNROLL is the number of times - the loop is to be unrolled. The parameter LOOP is a pointer to the - loop, which is going to be checked for unrolling. This target hook - is required only when the target has special constraints like - maximum number of memory accesses. - - -- Macro: 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 - 'pow', 'powf' or 'powl' routines. The default value places no - upper bound on the multiplication count. - - -- Macro: void TARGET_EXTRA_INCLUDES (const char *SYSROOT, const char - *IPREFIX, int STDINC) - This target hook should register any extra include files for the - target. The parameter STDINC indicates if normal include files are - present. The parameter SYSROOT is the system root directory. The - parameter IPREFIX is the prefix for the gcc directory. - - -- Macro: void TARGET_EXTRA_PRE_INCLUDES (const char *SYSROOT, const - char *IPREFIX, int STDINC) - This target hook should register any extra include files for the - target before any standard headers. The parameter STDINC indicates - if normal include files are present. The parameter SYSROOT is the - system root directory. The parameter IPREFIX is the prefix for the - gcc directory. - - -- Macro: void TARGET_OPTF (char *PATH) - This target hook should register special include paths for the - target. The parameter PATH is the include to register. On Darwin - systems, this is used for Framework includes, which have semantics - that are different from '-I'. - - -- Macro: bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree FNDECL) - This target macro returns 'true' if it is safe to use a local alias - for a virtual function FNDECL when constructing thunks, 'false' - otherwise. By default, the macro returns 'true' for all functions, - if a target supports aliases (i.e. defines 'ASM_OUTPUT_DEF'), - 'false' otherwise, - - -- Macro: TARGET_FORMAT_TYPES - If defined, this macro is the name of a global variable containing - target-specific format checking information for the '-Wformat' - option. The default is to have no target-specific format checks. - - -- Macro: TARGET_N_FORMAT_TYPES - If defined, this macro is the number of entries in - 'TARGET_FORMAT_TYPES'. - - -- Macro: TARGET_OVERRIDES_FORMAT_ATTRIBUTES - If defined, this macro is the name of a global variable containing - target-specific format overrides for the '-Wformat' option. The - default is to have no target-specific format overrides. If - defined, 'TARGET_FORMAT_TYPES' must be defined, too. - - -- Macro: TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT - If defined, this macro specifies the number of entries in - 'TARGET_OVERRIDES_FORMAT_ATTRIBUTES'. - - -- Macro: TARGET_OVERRIDES_FORMAT_INIT - If defined, this macro specifies the optional initialization - routine for target specific customizations of the system printf and - scanf formatter settings. - - -- Target Hook: bool TARGET_RELAXED_ORDERING - If set to '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 'false'. - - -- Target Hook: const char * TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN - (const_tree TYPELIST, const_tree FUNCDECL, const_tree VAL) - If defined, this macro returns the diagnostic message when it is - illegal to pass argument VAL to function FUNCDECL with prototype - TYPELIST. - - -- Target Hook: const char * TARGET_INVALID_CONVERSION (const_tree - FROMTYPE, const_tree TOTYPE) - If defined, this macro returns the diagnostic message when it is - invalid to convert from FROMTYPE to TOTYPE, or 'NULL' if validity - should be determined by the front end. - - -- Target Hook: const char * TARGET_INVALID_UNARY_OP (int OP, - const_tree TYPE) - If defined, this macro returns the diagnostic message when it is - invalid to apply operation OP (where unary plus is denoted by - 'CONVERT_EXPR') to an operand of type TYPE, or 'NULL' if validity - should be determined by the front end. - - -- Target Hook: const char * TARGET_INVALID_BINARY_OP (int OP, - const_tree TYPE1, const_tree TYPE2) - If defined, this macro returns the diagnostic message when it is - invalid to apply operation OP to operands of types TYPE1 and TYPE2, - or 'NULL' if validity should be determined by the front end. - - -- Target Hook: const char * TARGET_INVALID_PARAMETER_TYPE (const_tree - TYPE) - If defined, this macro returns the diagnostic message when it is - invalid for functions to include parameters of type TYPE, or 'NULL' - if validity should be determined by the front end. This is - currently used only by the C and C++ front ends. - - -- Target Hook: const char * TARGET_INVALID_RETURN_TYPE (const_tree - TYPE) - If defined, this macro returns the diagnostic message when it is - invalid for functions to have return type TYPE, or 'NULL' if - validity should be determined by the front end. This is currently - used only by the C and C++ front ends. - - -- Target Hook: tree TARGET_PROMOTED_TYPE (const_tree TYPE) - If defined, this target hook returns the type to which values of - TYPE should be promoted when they appear in expressions, analogous - to the integer promotions, or 'NULL_TREE' to use the front end's - normal promotion rules. This hook is useful when there are - target-specific types with special promotion rules. This is - currently used only by the C and C++ front ends. - - -- Target Hook: tree TARGET_CONVERT_TO_TYPE (tree TYPE, tree EXPR) - If defined, this hook returns the result of converting EXPR to - TYPE. It should return the converted expression, or 'NULL_TREE' to - apply the front end's normal conversion rules. This hook is useful - when there are target-specific types with special conversion rules. - This is currently used only by the C and C++ front ends. - - -- Macro: 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. - - -- Macro: 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. - - -- Macro: LIBGCC2_UNWIND_ATTRIBUTE - Define this macro if any target-specific attributes need to be - attached to the functions in 'libgcc' that provide low-level - support for call stack unwinding. It is used in declarations in - 'unwind-generic.h' and the associated definitions of those - functions. - - -- Target Hook: void TARGET_UPDATE_STACK_BOUNDARY (void) - Define this macro to update the current function stack boundary if - necessary. - - -- Target Hook: rtx TARGET_GET_DRAP_RTX (void) - This hook should return an rtx for Dynamic Realign Argument Pointer - (DRAP) if a different argument pointer register is needed to access - the function's argument list due to stack realignment. Return - 'NULL' if no DRAP is needed. - - -- Target Hook: bool TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS (void) - When optimization is disabled, this hook indicates whether or not - arguments should be allocated to stack slots. Normally, GCC - allocates stacks slots for arguments when not optimizing in order - to make debugging easier. However, when a function is declared - with '__attribute__((naked))', there is no stack frame, and the - compiler cannot safely move arguments from the registers in which - they are passed to the stack. Therefore, this hook should return - true in general, but false for naked functions. The default - implementation always returns true. - - -- Target Hook: unsigned HOST_WIDE_INT TARGET_CONST_ANCHOR - On some architectures it can take multiple instructions to - synthesize a constant. If there is another constant already in a - register that is close enough in value then it is preferable that - the new constant is computed from this register using immediate - addition or subtraction. We accomplish this through CSE. Besides - the value of the constant we also add a lower and an upper constant - anchor to the available expressions. These are then queried when - encountering new constants. The anchors are computed by rounding - the constant up and down to a multiple of the value of - 'TARGET_CONST_ANCHOR'. 'TARGET_CONST_ANCHOR' should be the maximum - positive value accepted by immediate-add plus one. We currently - assume that the value of 'TARGET_CONST_ANCHOR' is a power of 2. - For example, on MIPS, where add-immediate takes a 16-bit signed - value, 'TARGET_CONST_ANCHOR' is set to '0x8000'. The default value - is zero, which disables this optimization. - - -- Target Hook: unsigned HOST_WIDE_INT TARGET_ASAN_SHADOW_OFFSET (void) - Return the offset bitwise ored into shifted address to get - corresponding Address Sanitizer shadow memory address. NULL if - Address Sanitizer is not supported by the target. - - -- Target Hook: unsigned HOST_WIDE_INT TARGET_MEMMODEL_CHECK (unsigned - HOST_WIDE_INT VAL) - Validate target specific memory model mask bits. When NULL no - target specific memory model bits are allowed. - - -- Target Hook: unsigned char TARGET_ATOMIC_TEST_AND_SET_TRUEVAL - This value should be set if the result written by - 'atomic_test_and_set' is not exactly 1, i.e. the 'bool' 'true'. - - -- Target Hook: bool TARGET_HAS_IFUNC_P (void) - It returns true if the target supports GNU indirect functions. The - support includes the assembler, linker and dynamic linker. The - default value of this hook is based on target's libc. - - -- Target Hook: unsigned int TARGET_ATOMIC_ALIGN_FOR_MODE (enum - machine_mode MODE) - If defined, this function returns an appropriate alignment in bits - for an atomic object of machine_mode MODE. If 0 is returned then - the default alignment for the specified mode is used. - - -- Target Hook: void TARGET_ATOMIC_ASSIGN_EXPAND_FENV (tree *HOLD, tree - *CLEAR, tree *UPDATE) - ISO C11 requires atomic compound assignments that may raise - floating-point exceptions to raise exceptions corresponding to the - arithmetic operation whose result was successfully stored in a - compare-and-exchange sequence. This requires code equivalent to - calls to 'feholdexcept', 'feclearexcept' and 'feupdateenv' to be - generated at appropriate points in the compare-and-exchange - sequence. This hook should set '*HOLD' to an expression equivalent - to the call to 'feholdexcept', '*CLEAR' to an expression equivalent - to the call to 'feclearexcept' and '*UPDATE' to an expression - equivalent to the call to 'feupdateenv'. The three expressions are - 'NULL_TREE' on entry to the hook and may be left as 'NULL_TREE' if - no code is required in a particular place. The default - implementation leaves all three expressions as 'NULL_TREE'. The - '__atomic_feraiseexcept' function from 'libatomic' may be of use as - part of the code generated in '*UPDATE'. - - -File: gccint.info, Node: Host Config, Next: Fragments, Prev: Target Macros, Up: Top - -18 Host Configuration -********************* - -Most details about the machine and system on which the compiler is -actually running are detected by the 'configure' script. Some things -are impossible for 'configure' to detect; these are described in two -ways, either by macros defined in a file named 'xm-MACHINE.h' or by hook -functions in the file specified by the OUT_HOST_HOOK_OBJ variable in -'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 'xm_defines' variable in your -'config.gcc' entry instead of creating a host configuration header. -*Note 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. - - -File: gccint.info, Node: Host Common, Next: Filesystem, Up: Host Config - -18.1 Host Common -================ - -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 -HOST_HOOK_OBJ variable in 'config.gcc'. - - -- 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. - - -- Host Hook: void * HOST_HOOKS_GT_PCH_GET_ADDRESS (size_t SIZE, int - 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 SIZE bytes. If the - host uses 'mmap', FD is an open file descriptor that can be used - for probing. - - -- Host Hook: int HOST_HOOKS_GT_PCH_USE_ADDRESS (void * ADDRESS, size_t - SIZE, int FD, size_t OFFSET) - This host hook is called when a PCH file is about to be loaded. We - want to load SIZE bytes from FD at OFFSET into memory at ADDRESS. - The given address will be the result of a previous invocation of - 'HOST_HOOKS_GT_PCH_GET_ADDRESS'. Return -1 if we couldn't allocate - SIZE bytes at 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 SIZE, regardless of the return value. If no - PCH will be loaded, this hook may be called with SIZE zero, in - which case all reserved address space should be freed. - - Do not try to handle values of ADDRESS that could not have been - returned by this executable; just return -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. - - -- 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. - - -File: gccint.info, Node: Filesystem, Next: Host Misc, Prev: Host Common, Up: Host Config - -18.2 Host Filesystem -==================== - -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 'xm-MACHINE.h'. - -'HAVE_DOS_BASED_FILE_SYSTEM' - This macro is automatically defined by '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 ('/' and - '\') are directory separators. - -'DIR_SEPARATOR' -'DIR_SEPARATOR_2' - If defined, these macros expand to character constants specifying - separators for directory names within a file specification. - '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 'xm-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. - -'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 (':'). DOS-based systems usually, but not always, - use semicolon (';'). - -'VMS' - Define this macro if the host system is VMS. - -'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 '.o' as the suffix for object files. - -'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. - -'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 "bit bucket" or "null - device". If you do not define this macro, GCC will use '/dev/null' - as the bit bucket. If the host does not support a bit bucket, - define this macro to an invalid filename. - -'UPDATE_PATH_HOST_CANONICALIZE (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. PATH is a malloc-ed path - to be canonicalized. If the C statement does canonicalize PATH - into a different buffer, the old path should be freed and the new - buffer should have been allocated with malloc. - -'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. 'rtl'. - - If you do not define this macro, GCC will use '.%02d.'. You should - define this macro if using the default will create an invalid file - name. - -'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. - -'HOST_LACKS_INODE_NUMBERS' - Define this macro if the host filesystem does not report meaningful - inode numbers in struct stat. - - -File: gccint.info, Node: Host Misc, Prev: Filesystem, Up: Host Config - -18.3 Host Misc -============== - -'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 'EXIT_FAILURE', or '1' if the system doesn't define that - macro. Define this macro only if these defaults are incorrect. - -'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 'EXIT_SUCCESS', or '0' if - the system doesn't define that macro. Define this macro only if - these defaults are incorrect. - -'USE_C_ALLOCA' - Define this macro if GCC should use the C implementation of - 'alloca' provided by '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 '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 'alloca' can possibly work. For instance, if a - system has a small limit on the size of the stack, GCC's builtin - 'alloca' will not work reliably. - -'COLLECT2_HOST_INITIALIZATION' - If defined, a C statement (sans semicolon) that performs - host-dependent initialization when 'collect2' is being initialized. - -'GCC_DRIVER_HOST_INITIALIZATION' - If defined, a C statement (sans semicolon) that performs - host-dependent initialization when a compilation driver is being - initialized. - -'HOST_LONG_LONG_FORMAT' - If defined, the string used to indicate an argument of type 'long - long' to functions like 'printf'. The default value is '"ll"'. - -'HOST_LONG_FORMAT' - If defined, the string used to indicate an argument of type 'long' - to functions like 'printf'. The default value is '"l"'. - -'HOST_PTR_PRINTF' - If defined, the string used to indicate an argument of type 'void - *' to functions like 'printf'. The default value is '"%p"'. - - In addition, if 'configure' generates an incorrect definition of any of -the macros in '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 'configure'. - - -File: gccint.info, Node: Fragments, Next: Collect2, Prev: Host Config, Up: Top - -19 Makefile Fragments -********************* - -When you configure GCC using the 'configure' script, it will construct -the file 'Makefile' from the template file 'Makefile.in'. When it does -this, it can incorporate makefile fragments from the '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 -'config.gcc' (and occasionally 'config.build' and 'config.host'); *Note -System Config::. - - Fragments are named either 't-TARGET' or 'x-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 TARGET -and 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 't-TARGET' fragments, but -needing 'x-HOST' fragments is rare. - -* Menu: - -* Target Fragment:: Writing 't-TARGET' files. -* Host Fragment:: Writing 'x-HOST' files. - - -File: gccint.info, Node: Target Fragment, Next: Host Fragment, Up: Fragments - -19.1 Target Makefile Fragments -============================== - -Target makefile fragments can set these Makefile variables. - -'LIBGCC2_CFLAGS' - Compiler flags to use when compiling 'libgcc2.c'. - -'LIB2FUNCS_EXTRA' - A list of source file names to be compiled or assembled and - inserted into 'libgcc.a'. - -'CRTSTUFF_T_CFLAGS' - Special flags used when compiling 'crtstuff.c'. *Note - Initialization::. - -'CRTSTUFF_T_CFLAGS_S' - Special flags used when compiling 'crtstuff.c' for shared linking. - Used if you use 'crtbeginS.o' and 'crtendS.o' in 'EXTRA-PARTS'. - *Note Initialization::. - -'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 '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 'libgcc.a', - based on the command line options used. - - The 'MULTILIB_OPTIONS' macro lists the set of options for which - special versions of '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 'MULTILIB_OPTIONS' to 'm68000/m68020 - msoft-float', 'Makefile' will build special versions of 'libgcc.a' - using the following sets of options: '-m68000', '-m68020', - '-msoft-float', '-m68000 -msoft-float', and '-m68020 -msoft-float'. - -'MULTILIB_DIRNAMES' - If 'MULTILIB_OPTIONS' is used, this variable specifies the - directory names that should be used to hold the various libraries. - Write one element in 'MULTILIB_DIRNAMES' for each element in - 'MULTILIB_OPTIONS'. If 'MULTILIB_DIRNAMES' is not used, the - default value will be 'MULTILIB_OPTIONS', with all slashes treated - as spaces. - - 'MULTILIB_DIRNAMES' describes the multilib directories using GCC - conventions and is applied to directories that are part of the GCC - installation. When multilib-enabled, the compiler will add a - subdirectory of the form PREFIX/MULTILIB before each directory in - the search path for libraries and crt files. - - For example, if 'MULTILIB_OPTIONS' is set to 'm68000/m68020 - msoft-float', then the default value of 'MULTILIB_DIRNAMES' is - 'm68000 m68020 msoft-float'. You may specify a different value if - you desire a different set of directory names. - -'MULTILIB_MATCHES' - Sometimes the same option may be written in two different ways. If - an option is listed in 'MULTILIB_OPTIONS', GCC needs to know about - any synonyms. In that case, set 'MULTILIB_MATCHES' to a list of - items of the form 'option=option' to describe all relevant - synonyms. For example, 'm68000=mc68000 m68020=mc68020'. - -'MULTILIB_EXCEPTIONS' - Sometimes when there are multiple sets of 'MULTILIB_OPTIONS' being - specified, there are combinations that should not be built. In - that case, set '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 'MULTILIB_EXCEPTIONS' is set to: - *mthumb/*mhard-float* - -'MULTILIB_REQUIRED' - Sometimes when there are only a few combinations are required, it - would be a big effort to come up with a 'MULTILIB_EXCEPTIONS' list - to cover all undesired ones. In such a case, just listing all the - required combinations in 'MULTILIB_REQUIRED' would be more - straightforward. - - The way to specify the entries in 'MULTILIB_REQUIRED' is same with - the way used for 'MULTILIB_EXCEPTIONS', only this time what are - required will be specified. Suppose there are multiple sets of - 'MULTILIB_OPTIONS' and only two combinations are required, one for - ARMv7-M and one for ARMv7-R with hard floating-point ABI and FPU, - the 'MULTILIB_REQUIRED' can be set to: - MULTILIB_REQUIRED = mthumb/march=armv7-m - MULTILIB_REQUIRED += march=armv7-r/mfloat-abi=hard/mfpu=vfpv3-d16 - - The 'MULTILIB_REQUIRED' can be used together with - 'MULTILIB_EXCEPTIONS'. The option combinations generated from - 'MULTILIB_OPTIONS' will be filtered by 'MULTILIB_EXCEPTIONS' and - then by 'MULTILIB_REQUIRED'. - -'MULTILIB_REUSE' - Sometimes it is desirable to reuse one existing multilib for - different sets of options. Such kind of reuse can minimize the - number of multilib variants. And for some targets it is better to - reuse an existing multilib than to fall back to default multilib - when there is no corresponding multilib. This can be done by - adding reuse rules to 'MULTILIB_REUSE'. - - A reuse rule is comprised of two parts connected by equality sign. - The left part is option set used to build multilib and the right - part is option set that will reuse this multilib. The order of - options in the left part matters and should be same with those - specified in 'MULTILIB_REQUIRED' or aligned with order in - 'MULTILIB_OPTIONS'. There is no such limitation for options in - right part as we don't build multilib from them. But the equality - sign in both parts should be replaced with period. - - The 'MULTILIB_REUSE' is different from 'MULTILIB_MATCHES' in that - it sets up relations between two option sets rather than two - options. Here is an example to demo how we reuse libraries built - in Thumb mode for applications built in ARM mode: - MULTILIB_REUSE = mthumb/march.armv7-r=marm/march.armv7-r - - Before the advent of 'MULTILIB_REUSE', GCC select multilib by - comparing command line options with options used to build multilib. - The 'MULTILIB_REUSE' is complementary to that way. Only when the - original comparison matches nothing it will work to see if it is OK - to reuse some existing multilib. - -'MULTILIB_EXTRA_OPTS' - Sometimes it is desirable that when building multiple versions of - 'libgcc.a' certain options should always be passed on to the - compiler. In that case, set 'MULTILIB_EXTRA_OPTS' to be the list - of options to be used for all builds. If you set this, you should - probably set 'CRTSTUFF_T_CFLAGS' to a dash followed by it. - -'MULTILIB_OSDIRNAMES' - If 'MULTILIB_OPTIONS' is used, this variable specifies a list of - subdirectory names, that are used to modify the search path - depending on the chosen multilib. Unlike 'MULTILIB_DIRNAMES', - 'MULTILIB_OSDIRNAMES' describes the multilib directories using - operating systems conventions, and is applied to the directories - such as 'lib' or those in the 'LIBRARY_PATH' environment variable. - The format is either the same as of 'MULTILIB_DIRNAMES', or a set - of mappings. When it is the same as 'MULTILIB_DIRNAMES', it - describes the multilib directories using operating system - conventions, rather than GCC conventions. When it is a set of - mappings of the form GCCDIR=OSDIR, the left side gives the GCC - convention and the right gives the equivalent OS defined location. - If the OSDIR part begins with a '!', GCC will not search in the - non-multilib directory and use exclusively the multilib directory. - Otherwise, the compiler will examine the search path for libraries - and crt files twice; the first time it will add MULTILIB to each - directory in the search path, the second it will not. - - For configurations that support both multilib and multiarch, - 'MULTILIB_OSDIRNAMES' also encodes the multiarch name, thus - subsuming 'MULTIARCH_DIRNAME'. The multiarch name is appended to - each directory name, separated by a colon (e.g. - '../lib32:i386-linux-gnu'). - - Each multiarch subdirectory will be searched before the - corresponding OS multilib directory, for example - '/lib/i386-linux-gnu' before '/lib/../lib32'. The multiarch name - will also be used to modify the system header search path, as - explained for 'MULTIARCH_DIRNAME'. - -'MULTIARCH_DIRNAME' - This variable specifies the multiarch name for configurations that - are multiarch-enabled but not multilibbed configurations. - - The multiarch name is used to augment the search path for - libraries, crt files and system header files with additional - locations. The compiler will add a multiarch subdirectory of the - form PREFIX/MULTIARCH before each directory in the library and crt - search path. It will also add two directories - 'LOCAL_INCLUDE_DIR'/MULTIARCH and - 'NATIVE_SYSTEM_HEADER_DIR'/MULTIARCH) to the system header search - path, respectively before 'LOCAL_INCLUDE_DIR' and - 'NATIVE_SYSTEM_HEADER_DIR'. - - 'MULTIARCH_DIRNAME' is not used for configurations that support - both multilib and multiarch. In that case, multiarch names are - encoded in 'MULTILIB_OSDIRNAMES' instead. - - More documentation about multiarch can be found at - <http://wiki.debian.org/Multiarch>. - -'SPECS' - Unfortunately, setting '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 - 'DRIVER_SELF_SPECS' to bring options from the '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 'specs' file that will be - used during the toolchain build, while you still install the - original, built-in 'specs'. The trick is to set 'SPECS' to some - other filename (say 'specs.install'), that will then be created out - of the built-in specs, and introduce a 'Makefile' rule to generate - the 'specs' file that's going to be used at build time out of your - 'specs.install'. - -'T_CFLAGS' - These are extra flags to pass to the C compiler. They are used - both when building GCC, and when compiling things with the - just-built GCC. This variable is deprecated and should not be - used. - - -File: gccint.info, Node: Host Fragment, Prev: Target Fragment, Up: Fragments - -19.2 Host Makefile Fragments -============================ - -The use of 'x-HOST' fragments is discouraged. You should only use it -for makefile dependencies. - - -File: gccint.info, Node: Collect2, Next: Header Dirs, Prev: Fragments, Up: Top - -20 'collect2' -************* - -GCC uses a utility called 'collect2' on nearly all systems to arrange to -call various initialization functions at start time. - - The program '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 '.c' file containing a table of them, compiles it, and -links the program a second time including that file. - - The actual calls to the constructors are carried out by a subroutine -called '__main', which is called (automatically) at the beginning of the -body of 'main' (provided 'main' was compiled with GNU CC). Calling -'__main' is necessary, even when compiling C code, to allow linking C -and C++ object code together. (If you use '-nostdlib', you get an -unresolved reference to '__main', since it's defined in the standard GCC -library. Include '-lgcc' at the end of your compiler command line to -resolve this reference.) - - The program 'collect2' is installed as 'ld' in the directory where the -passes of the compiler are installed. When 'collect2' needs to find the -_real_ 'ld', it tries the following file names: - - * a hard coded linker file name, if GCC was configured with the - '--with-ld' option. - - * 'real-ld' in the directories listed in the compiler's search - directories. - - * 'real-ld' in the directories listed in the environment variable - 'PATH'. - - * The file specified in the 'REAL_LD_FILE_NAME' configuration macro, - if specified. - - * 'ld' in the compiler's search directories, except that 'collect2' - will not execute itself recursively. - - * 'ld' in 'PATH'. - - "The compiler's search directories" means all the directories where -'gcc' searches for passes of the compiler. This includes directories -that you specify with '-B'. - - Cross-compilers search a little differently: - - * 'real-ld' in the compiler's search directories. - - * 'TARGET-real-ld' in 'PATH'. - - * The file specified in the 'REAL_LD_FILE_NAME' configuration macro, - if specified. - - * 'ld' in the compiler's search directories. - - * 'TARGET-ld' in 'PATH'. - - 'collect2' explicitly avoids running 'ld' using the file name under -which 'collect2' itself was invoked. In fact, it remembers up a list of -such names--in case one copy of 'collect2' finds another copy (or -version) of 'collect2' installed as 'ld' in a second place in the search -path. - - 'collect2' searches for the utilities 'nm' and 'strip' using the same -algorithm as above for 'ld'. - - -File: gccint.info, Node: Header Dirs, Next: Type Information, Prev: Collect2, Up: Top - -21 Standard Header File Directories -*********************************** - -'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 'fixincludes' on the -header files in '$(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). - - 'GPLUSPLUS_INCLUDE_DIR' means the same thing for native and cross. It -is where 'g++' looks first for header files. The C++ library installs -only target independent header files in that directory. - - 'LOCAL_INCLUDE_DIR' is used only by native compilers. GCC doesn't -install anything there. It is normally '/usr/local/include'. This is -where local additions to a packaged system should place header files. - - 'CROSS_INCLUDE_DIR' is used only by cross compilers. GCC doesn't -install anything there. - - '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 '/usr/include'. When -you build a cross-compiler, 'fixincludes' processes any header files in -this directory. - - -File: gccint.info, Node: Type Information, Next: Plugins, Prev: Header Dirs, Up: Top - -22 Memory Management and Type Information -***************************************** - -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 'struct', 'union' and -'template' structure 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 - GTY (([OPTION] [(PARAM)], [OPTION] [(PARAM)] ...)) -but in most cases no options are needed. The outer double parentheses -are still necessary, though: 'GTY(())'. Markers can appear: - - * In a structure definition, before the open brace; - * In a global variable declaration, after the keyword 'static' or - 'extern'; and - * In a structure field definition, before the name of the field. - - Here are some examples of marking simple data structures and globals. - - struct GTY(()) TAG - { - FIELDS... - }; - - typedef struct GTY(()) TAG - { - FIELDS... - } *TYPENAME; - - static GTY(()) struct TAG *LIST; /* points to GC memory */ - static GTY(()) int COUNTER; /* save counter in a PCH */ - - The parser understands simple typedefs such as 'typedef struct TAG -*NAME;' and 'typedef int NAME;'. These don't need to be marked. - - Since 'gengtype''s understanding of C++ is limited, there are several -constructs and declarations that are not supported inside -classes/structures marked for automatic GC code generation. The -following C++ constructs produce a 'gengtype' error on -structures/classes marked for automatic GC code generation: - - * Type definitions inside classes/structures are not supported. - * Enumerations inside classes/structures are not supported. - - If you have a class or structure using any of the above constructs, you -need to mark that class as 'GTY ((user))' and provide your own marking -routines (see section *note User GC:: for details). - - It is always valid to include function definitions inside classes. -Those are always ignored by 'gengtype', as it only cares about data -members. - -* Menu: - -* GTY Options:: What goes inside a 'GTY(())'. -* Inheritance and GTY:: Adding GTY to a class hierarchy. -* User GC:: Adding user-provided GC marking routines. -* GGC Roots:: Making global variables GGC roots. -* Files:: How the generated files work. -* Invoking the garbage collector:: How to invoke the garbage collector. -* Troubleshooting:: When something does not work as expected. - - -File: gccint.info, Node: GTY Options, Next: Inheritance and GTY, Up: Type Information - -22.1 The Inside of a 'GTY(())' -============================== - -Sometimes the C code is not enough to fully describe the type structure. -Extra information can be provided with '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, 'GTY ((skip))' and -'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: - -'%h' - The current structure. -'%1' - The structure that immediately contains the current structure. -'%0' - The outermost structure that contains the current structure. -'%a' - A partial expression of the form '[i1][i2]...' that indexes the - array item currently being marked. - - For instance, suppose that you have a structure of the form - struct A { - ... - }; - struct B { - struct A foo[12]; - }; -and 'b' is a variable of type 'struct B'. When marking 'b.foo[11]', -'%h' would expand to 'b.foo[11]', '%0' and '%1' would both expand to -'b', and '%a' would expand to '[11]'. - - As in ordinary C, adjacent strings will be concatenated; this is -helpful when you have a complicated expression. - GTY ((chain_next ("TREE_CODE (&%h.generic) == INTEGER_TYPE" - " ? TYPE_NEXT_VARIANT (&%h.generic)" - " : TREE_CHAIN (&%h.generic)"))) - - The available options are: - -'length ("EXPRESSION")' - - There are two places the type machinery will need to be explicitly - told the length of an array of non-atomic objects. The first case - is when a structure ends in a variable-length array, like this: - struct GTY(()) rtvec_def { - int num_elem; /* number of elements */ - rtx GTY ((length ("%h.num_elem"))) elem[1]; - }; - - In this case, the 'length' option is used to override the specified - array length (which should usually be '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: - struct gimple_omp_for_iter * GTY((length ("%h.collapse"))) iter; - In this case, 'iter' has been allocated by writing something like - x->iter = ggc_alloc_cleared_vec_gimple_omp_for_iter (collapse); - and the 'collapse' provides the length of the field. - - This second use of 'length' also works on global variables, like: - static GTY((length("reg_known_value_size"))) rtx *reg_known_value; - - Note that the 'length' option is only meant for use with arrays of - non-atomic objects, that is, objects that contain pointers pointing - to other GTY-managed objects. For other GC-allocated arrays and - strings you should use 'atomic'. - -'skip' - - If '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. - -'desc ("EXPRESSION")' -'tag ("CONSTANT")' -'default' - - The type machinery needs to be told which field of a 'union' is - currently active. This is done by giving each field a constant - 'tag' value, and then specifying a discriminator using 'desc'. The - value of the expression given by 'desc' is compared against each - 'tag' value, each of which should be different. If no 'tag' is - matched, the field marked with 'default' is used if there is one, - otherwise no field in the union will be marked. - - In the 'desc' option, the "current structure" is the union that it - discriminates. Use '%1' to mean the structure containing it. - There are no escapes available to the 'tag' option, since it is a - constant. - - For example, - struct GTY(()) tree_binding - { - 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; - }; - - In this example, the value of BINDING_HAS_LEVEL_P when applied to a - 'struct tree_binding *' is presumed to be 0 or 1. If 1, the type - mechanism will treat the field 'level' as being present and if 0, - will treat the field 'scope' as being present. - - The 'desc' and 'tag' options can also be used for inheritance to - denote which subclass an instance is. See *note Inheritance and - GTY:: for more information. - -'param_is (TYPE)' -'use_param' - - Sometimes it's convenient to define some data structure to work on - generic pointers (that is, 'PTR') and then use it with a specific - type. 'param_is' specifies the real type pointed to, and - 'use_param' says where in the generic data structure that type - should be put. - - For instance, to have a 'htab_t' that points to trees, one would - write the definition of 'htab_t' like this: - typedef struct GTY(()) { - ... - void ** GTY ((use_param, ...)) entries; - ... - } htab_t; - and then declare variables like this: - static htab_t GTY ((param_is (union tree_node))) ict; - -'paramN_is (TYPE)' -'use_paramN' - - In more complicated cases, the data structure might need to work on - several different types, which might not necessarily all be - pointers. For this, 'param1_is' through 'param9_is' may be used to - specify the real type of a field identified by 'use_param1' through - 'use_param9'. - -'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 'use_params' option. - -'deletable' - - '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 'NULL' instead. This is - used to keep a list of free structures around for re-use. - -'if_marked ("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 '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 'ggc_marked_p' can be used to determine if an element - has been marked already; in fact, the usual case is to use - 'if_marked ("ggc_marked_p")'. - -'mark_hook ("HOOK-ROUTINE-NAME")' - - If provided for a structure or union type, the given - HOOK-ROUTINE-NAME (between double-quotes) is the name of a routine - called when the garbage collector has just marked the data as - reachable. This routine should not change the data, or call any - ggc routine. Its only argument is a pointer to the just marked - (const) structure or union. - -'maybe_undef' - - When applied to a field, '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 'NULL'. This is used to avoid requiring - backends to define certain optional structures. It doesn't work - with language frontends. - -'nested_ptr (TYPE, "TO EXPRESSION", "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. TYPE is the type of the original - object, the TO EXPRESSION returns the pointer given the original - object, and the FROM EXPRESSION returns the original object given - the pointer. The pointer will be available using the '%h' escape. - -'chain_next ("EXPRESSION")' -'chain_prev ("EXPRESSION")' -'chain_circular ("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. 'chain_next' is an expression for the next item - in the list, 'chain_prev' is an expression for the previous item. - For singly linked lists, use only 'chain_next'; for doubly linked - lists, use both. The machinery requires that taking the next item - of the previous item gives the original item. 'chain_circular' is - similar to 'chain_next', but can be used for circular single linked - lists. - -'reorder ("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 '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 - '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. '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. - -'variable_size' - - The type machinery expects the types to be of constant size. When - this is not true, for example, with structs that have array fields - or unions, the type machinery cannot tell how many bytes need to be - allocated at each allocation. The 'variable_size' is used to mark - such types. The type machinery then provides allocators that take - a parameter indicating an exact size of object being allocated. - Note that the size must be provided in bytes whereas the 'length' - option works with array lengths in number of elements. - - For example, - struct GTY((variable_size)) sorted_fields_type { - int len; - tree GTY((length ("%h.len"))) elts[1]; - }; - - Then the objects of 'struct sorted_fields_type' are allocated in GC - memory as follows: - field_vec = ggc_alloc_sorted_fields_type (size); - - If FIELD_VEC->ELTS stores N elements, then SIZE could be calculated - as follows: - size_t size = sizeof (struct sorted_fields_type) + n * sizeof (tree); - -'atomic' - - The 'atomic' option can only be used with pointers. It informs the - GC machinery that the memory that the pointer points to does not - contain any pointers, and hence it should be treated by the GC and - PCH machinery as an "atomic" block of memory that does not need to - be examined when scanning memory for pointers. In particular, the - machinery will not scan that memory for pointers to mark them as - reachable (when marking pointers for GC) or to relocate them (when - writing a PCH file). - - The 'atomic' option differs from the 'skip' option. 'atomic' keeps - the memory under Garbage Collection, but makes the GC ignore the - contents of the memory. 'skip' is more drastic in that it causes - the pointer and the memory to be completely ignored by the Garbage - Collector. So, memory marked as 'atomic' is automatically freed - when no longer reachable, while memory marked as 'skip' is not. - - The 'atomic' option must be used with great care, because all sorts - of problem can occur if used incorrectly, that is, if the memory - the pointer points to does actually contain a pointer. - - Here is an example of how to use it: - struct GTY(()) my_struct { - int number_of_elements; - unsigned int * GTY ((atomic)) elements; - }; - In this case, 'elements' is a pointer under GC, and the memory it - points to needs to be allocated using the Garbage Collector, and - will be freed automatically by the Garbage Collector when it is no - longer referenced. But the memory that the pointer points to is an - array of 'unsigned int' elements, and the GC must not try to scan - it to find pointers to mark or relocate, which is why it is marked - with the 'atomic' option. - - Note that, currently, global variables can not be marked with - 'atomic'; only fields of a struct can. This is a known limitation. - It would be useful to be able to mark global pointers with 'atomic' - to make the PCH machinery aware of them so that they are saved and - restored correctly to PCH files. - -'special ("NAME")' - - The '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 'gengtype.c' for further details. Avoid adding - new special cases unless there is no other alternative. - -'user' - - The 'user' option indicates that the code to mark structure fields - is completely handled by user-provided routines. See section *note - User GC:: for details on what functions need to be provided. - - -File: gccint.info, Node: Inheritance and GTY, Next: User GC, Prev: GTY Options, Up: Type Information - -22.2 Support for inheritance -============================ - -gengtype has some support for simple class hierarchies. You can use -this to have gengtype autogenerate marking routines, provided: - - * There must be a concrete base class, with a discriminator - expression that can be used to identify which subclass an instance - is. - * Only single inheritance is used. - * None of the classes within the hierarchy are templates. - - If your class hierarchy does not fit in this pattern, you must use -*note User GC:: instead. - - The base class and its discriminator must be identified using the -"desc" option. Each concrete subclass must use the "tag" option to -identify which value of the discriminator it corresponds to. - - Every class in the hierarchy must have a 'GTY(())' marker, as gengtype -will only attempt to parse classes that have such a marker (1). - - class GTY((desc("%h.kind"), tag("0"))) example_base - { - public: - int kind; - tree a; - }; - - class GTY((tag("1")) some_subclass : public example_base - { - public: - tree b; - }; - - class GTY((tag("2")) some_other_subclass : public example_base - { - public: - tree c; - }; - - The generated marking routines for the above will contain a "switch" on -"kind", visiting all appropriate fields. For example, if kind is 2, it -will cast to "some_other_subclass" and visit fields a, b, and c. - - ---------- Footnotes ---------- - - (1) Classes lacking such a marker will not be identified as being -part of the hierarchy, and so the marking routines will not handle them, -leading to a assertion failure within the marking routines due to an -unknown tag value (assuming that assertions are enabled). - - -File: gccint.info, Node: User GC, Next: GGC Roots, Prev: Inheritance and GTY, Up: Type Information - -22.3 Support for user-provided GC marking routines -================================================== - -The garbage collector supports types for which no automatic marking code -is generated. For these types, the user is required to provide three -functions: one to act as a marker for garbage collection, and two -functions to act as marker and pointer walker for pre-compiled headers. - - Given a structure 'struct GTY((user)) my_struct', the following -functions should be defined to mark 'my_struct': - - void gt_ggc_mx (my_struct *p) - { - /* This marks field 'fld'. */ - gt_ggc_mx (p->fld); - } - - void gt_pch_nx (my_struct *p) - { - /* This marks field 'fld'. */ - gt_pch_nx (tp->fld); - } - - void gt_pch_nx (my_struct *p, gt_pointer_operator op, void *cookie) - { - /* For every field 'fld', call the given pointer operator. */ - op (&(tp->fld), cookie); - } - - In general, each marker 'M' should call 'M' for every pointer field in -the structure. Fields that are not allocated in GC or are not pointers -must be ignored. - - For embedded lists (e.g., structures with a 'next' or 'prev' pointer), -the marker must follow the chain and mark every element in it. - - Note that the rules for the pointer walker 'gt_pch_nx (my_struct *, -gt_pointer_operator, void *)' are slightly different. In this case, the -operation 'op' must be applied to the _address_ of every pointer field. - -22.3.1 User-provided marking routines for template types --------------------------------------------------------- - -When a template type 'TP' is marked with 'GTY', all instances of that -type are considered user-provided types. This means that the individual -instances of 'TP' do not need to be marked with 'GTY'. The user needs -to provide template functions to mark all the fields of the type. - - The following code snippets represent all the functions that need to be -provided. Note that type 'TP' may reference to more than one type. In -these snippets, there is only one type 'T', but there could be more. - - template<typename T> - void gt_ggc_mx (TP<T> *tp) - { - extern void gt_ggc_mx (T&); - - /* This marks field 'fld' of type 'T'. */ - gt_ggc_mx (tp->fld); - } - - template<typename T> - void gt_pch_nx (TP<T> *tp) - { - extern void gt_pch_nx (T&); - - /* This marks field 'fld' of type 'T'. */ - gt_pch_nx (tp->fld); - } - - template<typename T> - void gt_pch_nx (TP<T *> *tp, gt_pointer_operator op, void *cookie) - { - /* For every field 'fld' of 'tp' with type 'T *', call the given - pointer operator. */ - op (&(tp->fld), cookie); - } - - template<typename T> - void gt_pch_nx (TP<T> *tp, gt_pointer_operator, void *cookie) - { - extern void gt_pch_nx (T *, gt_pointer_operator, void *); - - /* For every field 'fld' of 'tp' with type 'T', call the pointer - walker for all the fields of T. */ - gt_pch_nx (&(tp->fld), op, cookie); - } - - Support for user-defined types is currently limited. The following -restrictions apply: - - 1. Type 'TP' and all the argument types 'T' must be marked with 'GTY'. - - 2. Type 'TP' can only have type names in its argument list. - - 3. The pointer walker functions are different for 'TP<T>' and 'TP<T - *>'. In the case of 'TP<T>', references to 'T' must be handled by - calling 'gt_pch_nx' (which will, in turn, walk all the pointers - inside fields of 'T'). In the case of 'TP<T *>', references to 'T - *' must be handled by calling the 'op' function on the address of - the pointer (see the code snippets above). - - -File: gccint.info, Node: GGC Roots, Next: Files, Prev: User GC, Up: Type Information - -22.4 Marking Roots for the Garbage Collector -============================================ - -In addition to keeping track of types, the type machinery also locates -the global variables ("roots") that the garbage collector starts at. -Roots must be declared using one of the following syntaxes: - - * 'extern GTY(([OPTIONS])) TYPE NAME;' - * 'static GTY(([OPTIONS])) TYPE NAME;' -The syntax - * 'GTY(([OPTIONS])) TYPE NAME;' -is _not_ accepted. There should be an '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 'static'. - - -File: gccint.info, Node: Files, Next: Invoking the garbage collector, Prev: GGC Roots, Up: Type Information - -22.5 Source Files Containing Type Information -============================================= - -Whenever you add 'GTY' markers to a source file that previously had -none, or create a new source file containing 'GTY' markers, there are -three things you need to do: - - 1. You need to add the file to the list of source files the type - machinery scans. There are four cases: - - a. For a back-end file, this is usually done automatically; if - not, you should add it to 'target_gtfiles' in the appropriate - port's entries in 'config.gcc'. - - b. For files shared by all front ends, add the filename to the - 'GTFILES' variable in 'Makefile.in'. - - c. For files that are part of one front end, add the filename to - the 'gtfiles' variable defined in the appropriate - 'config-lang.in'. Headers should appear before non-headers in - this list. - - d. For files that are part of some but not all front ends, add - the filename to the 'gtfiles' variable of _all_ the front ends - that use it. - - 2. 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 'gtype-LANG.h'. For other header files, it needs to - be included in 'gtype-desc.c', which is a generated file, so add it - to 'ifiles' in 'open_base_file' in '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 'gt-PATH.h' where PATH - is the pathname relative to the 'gcc' directory with slashes - replaced by -, so for example the header file to be included in - 'cp/parser.c' is called '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 - 'Makefile'! - - For language frontends, there is another file that needs to be included -somewhere. It will be called 'gtype-LANG.h', where LANG is the name of -the subdirectory the language is contained in. - - Plugins can add additional root tables. Run the 'gengtype' utility in -plugin mode as 'gengtype -P pluginout.h SOURCE-DIR FILE-LIST PLUGIN*.C' -with your plugin files PLUGIN*.C using 'GTY' to generate the PLUGINOUT.H -file. The GCC build tree is needed to be present in that mode. - - -File: gccint.info, Node: Invoking the garbage collector, Next: Troubleshooting, Prev: Files, Up: Type Information - -22.6 How to invoke the garbage collector -======================================== - -The GCC garbage collector GGC is only invoked explicitly. In contrast -with many other garbage collectors, it is not implicitly invoked by -allocation routines when a lot of memory has been consumed. So the only -way to have GGC reclaim storage is to call the 'ggc_collect' function -explicitly. This call is an expensive operation, as it may have to scan -the entire heap. Beware that local variables (on the GCC call stack) -are not followed by such an invocation (as many other garbage collectors -do): you should reference all your data from static or external 'GTY'-ed -variables, and it is advised to call 'ggc_collect' with a shallow call -stack. The GGC is an exact mark and sweep garbage collector (so it does -not scan the call stack for pointers). In practice GCC passes don't -often call 'ggc_collect' themselves, because it is called by the pass -manager between passes. - - At the time of the 'ggc_collect' call all pointers in the GC-marked -structures must be valid or 'NULL'. In practice this means that there -should not be uninitialized pointer fields in the structures even if -your code never reads or writes those fields at a particular instance. -One way to ensure this is to use cleared versions of allocators unless -all the fields are initialized manually immediately after allocation. - - -File: gccint.info, Node: Troubleshooting, Prev: Invoking the garbage collector, Up: Type Information - -22.7 Troubleshooting the garbage collector -========================================== - -With the current garbage collector implementation, most issues should -show up as GCC compilation errors. Some of the most commonly -encountered issues are described below. - - * Gengtype does not produce allocators for a 'GTY'-marked type. - Gengtype checks if there is at least one possible path from GC - roots to at least one instance of each type before outputting - allocators. If there is no such path, the 'GTY' markers will be - ignored and no allocators will be output. Solve this by making - sure that there exists at least one such path. If creating it is - unfeasible or raises a "code smell", consider if you really must - use GC for allocating such type. - - * Link-time errors about undefined 'gt_ggc_r_foo_bar' and - similarly-named symbols. Check if your 'foo_bar' source file has - '#include "gt-foo_bar.h"' as its very last line. - - -File: gccint.info, Node: Plugins, Next: LTO, Prev: Type Information, Up: Top - -23 Plugins -********** - -GCC plugin is a loadable module that provides extra features to the -compiler, which they can further pass around as a shareable module. - - GCC plugins provide developers with a rich subset of the GCC API to -allow them to extend GCC as they see fit. Whether it is writing an -additional optimization pass, transforming code, or analyzing -information, plugins can be quite useful. - -* Menu: - -* Plugins loading:: How can we load plugins. -* Plugin API:: The APIs for plugins. -* Plugins pass:: How a plugin interact with the pass manager. -* Plugins GC:: How a plugin Interact with GCC Garbage Collector. -* Plugins description:: Giving information about a plugin itself. -* Plugins attr:: Registering custom attributes or pragmas. -* Plugins recording:: Recording information about pass execution. -* Plugins gate:: Controlling which passes are being run. -* Plugins tracking:: Keeping track of available passes. -* Plugins building:: How can we build a plugin. - - -File: gccint.info, Node: Plugins loading, Next: Plugin API, Up: Plugins - -23.1 Loading Plugins -==================== - -Plugins are supported on platforms that support '-ldl -rdynamic'. They -are loaded by the compiler using 'dlopen' and invoked at pre-determined -locations in the compilation process. - - Plugins are loaded with - - '-fplugin=/path/to/NAME.so' '-fplugin-arg-NAME-KEY1[=VALUE1]' - - The plugin arguments are parsed by GCC and passed to respective plugins -as key-value pairs. Multiple plugins can be invoked by specifying -multiple '-fplugin' arguments. - - A plugin can be simply given by its short name (no dots or slashes). -When simply passing '-fplugin=NAME', the plugin is loaded from the -'plugin' directory, so '-fplugin=NAME' is the same as '-fplugin=`gcc --print-file-name=plugin`/NAME.so', using backquote shell syntax to query -the 'plugin' directory. - - -File: gccint.info, Node: Plugin API, Next: Plugins pass, Prev: Plugins loading, Up: Plugins - -23.2 Plugin API -=============== - -Plugins are activated by the compiler at specific events as defined in -'gcc-plugin.h'. For each event of interest, the plugin should call -'register_callback' specifying the name of the event and address of the -callback function that will handle that event. - - The header 'gcc-plugin.h' must be the first gcc header to be included. - -23.2.1 Plugin license check ---------------------------- - -Every plugin should define the global symbol 'plugin_is_GPL_compatible' -to assert that it has been licensed under a GPL-compatible license. If -this symbol does not exist, the compiler will emit a fatal error and -exit with the error message: - - fatal error: plugin NAME is not licensed under a GPL-compatible license - NAME: undefined symbol: plugin_is_GPL_compatible - compilation terminated - - The declared type of the symbol should be int, to match a forward -declaration in 'gcc-plugin.h' that suppresses C++ mangling. It does not -need to be in any allocated section, though. The compiler merely -asserts that the symbol exists in the global scope. Something like this -is enough: - - int plugin_is_GPL_compatible; - -23.2.2 Plugin initialization ----------------------------- - -Every plugin should export a function called 'plugin_init' that is -called right after the plugin is loaded. This function is responsible -for registering all the callbacks required by the plugin and do any -other required initialization. - - This function is called from 'compile_file' right before invoking the -parser. The arguments to 'plugin_init' are: - - * 'plugin_info': Plugin invocation information. - * 'version': GCC version. - - The 'plugin_info' struct is defined as follows: - - struct plugin_name_args - { - char *base_name; /* Short name of the plugin - (filename without .so suffix). */ - const char *full_name; /* Path to the plugin as specified with - -fplugin=. */ - int argc; /* Number of arguments specified with - -fplugin-arg-.... */ - struct plugin_argument *argv; /* Array of ARGC key-value pairs. */ - const char *version; /* Version string provided by plugin. */ - const char *help; /* Help string provided by plugin. */ - } - - If initialization fails, 'plugin_init' must return a non-zero value. -Otherwise, it should return 0. - - The version of the GCC compiler loading the plugin is described by the -following structure: - - struct plugin_gcc_version - { - const char *basever; - const char *datestamp; - const char *devphase; - const char *revision; - const char *configuration_arguments; - }; - - The function 'plugin_default_version_check' takes two pointers to such -structure and compare them field by field. It can be used by the -plugin's 'plugin_init' function. - - The version of GCC used to compile the plugin can be found in the -symbol 'gcc_version' defined in the header 'plugin-version.h'. The -recommended version check to perform looks like - - #include "plugin-version.h" - ... - - int - plugin_init (struct plugin_name_args *plugin_info, - struct plugin_gcc_version *version) - { - if (!plugin_default_version_check (version, &gcc_version)) - return 1; - - } - - but you can also check the individual fields if you want a less strict -check. - -23.2.3 Plugin callbacks ------------------------ - -Callback functions have the following prototype: - - /* The prototype for a plugin callback function. - gcc_data - event-specific data provided by GCC - user_data - plugin-specific data provided by the plug-in. */ - typedef void (*plugin_callback_func)(void *gcc_data, void *user_data); - - Callbacks can be invoked at the following pre-determined events: - - enum plugin_event - { - PLUGIN_PASS_MANAGER_SETUP, /* To hook into pass manager. */ - PLUGIN_FINISH_TYPE, /* After finishing parsing a type. */ - PLUGIN_FINISH_DECL, /* After finishing parsing a declaration. */ - PLUGIN_FINISH_UNIT, /* Useful for summary processing. */ - PLUGIN_PRE_GENERICIZE, /* Allows to see low level AST in C and C++ frontends. */ - PLUGIN_FINISH, /* Called before GCC exits. */ - PLUGIN_INFO, /* Information about the plugin. */ - PLUGIN_GGC_START, /* Called at start of GCC Garbage Collection. */ - PLUGIN_GGC_MARKING, /* Extend the GGC marking. */ - PLUGIN_GGC_END, /* Called at end of GGC. */ - PLUGIN_REGISTER_GGC_ROOTS, /* Register an extra GGC root table. */ - PLUGIN_REGISTER_GGC_CACHES, /* Register an extra GGC cache table. */ - PLUGIN_ATTRIBUTES, /* Called during attribute registration */ - PLUGIN_START_UNIT, /* Called before processing a translation unit. */ - PLUGIN_PRAGMAS, /* Called during pragma registration. */ - /* Called before first pass from all_passes. */ - PLUGIN_ALL_PASSES_START, - /* Called after last pass from all_passes. */ - PLUGIN_ALL_PASSES_END, - /* Called before first ipa pass. */ - PLUGIN_ALL_IPA_PASSES_START, - /* Called after last ipa pass. */ - PLUGIN_ALL_IPA_PASSES_END, - /* Allows to override pass gate decision for current_pass. */ - PLUGIN_OVERRIDE_GATE, - /* Called before executing a pass. */ - PLUGIN_PASS_EXECUTION, - /* Called before executing subpasses of a GIMPLE_PASS in - execute_ipa_pass_list. */ - PLUGIN_EARLY_GIMPLE_PASSES_START, - /* Called after executing subpasses of a GIMPLE_PASS in - execute_ipa_pass_list. */ - PLUGIN_EARLY_GIMPLE_PASSES_END, - /* Called when a pass is first instantiated. */ - PLUGIN_NEW_PASS, - /* Called when a file is #include-d or given via the #line directive. - This could happen many times. The event data is the included file path, - as a const char* pointer. */ - PLUGIN_INCLUDE_FILE, - - PLUGIN_EVENT_FIRST_DYNAMIC /* Dummy event used for indexing callback - array. */ - }; - - In addition, plugins can also look up the enumerator of a named event, -and / or generate new events dynamically, by calling the function -'get_named_event_id'. - - To register a callback, the plugin calls 'register_callback' with the -arguments: - - * 'char *name': Plugin name. - * 'int event': The event code. - * 'plugin_callback_func callback': The function that handles 'event'. - * 'void *user_data': Pointer to plugin-specific data. - - For the PLUGIN_PASS_MANAGER_SETUP, PLUGIN_INFO, -PLUGIN_REGISTER_GGC_ROOTS and PLUGIN_REGISTER_GGC_CACHES pseudo-events -the 'callback' should be null, and the 'user_data' is specific. - - When the PLUGIN_PRAGMAS event is triggered (with a null pointer as data -from GCC), plugins may register their own pragmas. Notice that pragmas -are not available from 'lto1', so plugins used with '-flto' option to -GCC during link-time optimization cannot use pragmas and do not even see -functions like 'c_register_pragma' or 'pragma_lex'. - - The PLUGIN_INCLUDE_FILE event, with a 'const char*' file path as GCC -data, is triggered for processing of '#include' or '#line' directives. - - The PLUGIN_FINISH event is the last time that plugins can call GCC -functions, notably emit diagnostics with 'warning', 'error' etc. - - -File: gccint.info, Node: Plugins pass, Next: Plugins GC, Prev: Plugin API, Up: Plugins - -23.3 Interacting with the pass manager -====================================== - -There needs to be a way to add/reorder/remove passes dynamically. This -is useful for both analysis plugins (plugging in after a certain pass -such as CFG or an IPA pass) and optimization plugins. - - Basic support for inserting new passes or replacing existing passes is -provided. A plugin registers a new pass with GCC by calling -'register_callback' with the 'PLUGIN_PASS_MANAGER_SETUP' event and a -pointer to a 'struct register_pass_info' object defined as follows - - enum pass_positioning_ops - { - PASS_POS_INSERT_AFTER, // Insert after the reference pass. - PASS_POS_INSERT_BEFORE, // Insert before the reference pass. - PASS_POS_REPLACE // Replace the reference pass. - }; - - struct register_pass_info - { - struct opt_pass *pass; /* New pass provided by the plugin. */ - const char *reference_pass_name; /* Name of the reference pass for hooking - up the new pass. */ - int ref_pass_instance_number; /* Insert the pass at the specified - instance number of the reference pass. */ - /* Do it for every instance if it is 0. */ - enum pass_positioning_ops pos_op; /* how to insert the new pass. */ - }; - - - /* Sample plugin code that registers a new pass. */ - int - plugin_init (struct plugin_name_args *plugin_info, - struct plugin_gcc_version *version) - { - struct register_pass_info pass_info; - - ... - - /* Code to fill in the pass_info object with new pass information. */ - - ... - - /* Register the new pass. */ - register_callback (plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &pass_info); - - ... - } - - -File: gccint.info, Node: Plugins GC, Next: Plugins description, Prev: Plugins pass, Up: Plugins - -23.4 Interacting with the GCC Garbage Collector -=============================================== - -Some plugins may want to be informed when GGC (the GCC Garbage -Collector) is running. They can register callbacks for the -'PLUGIN_GGC_START' and 'PLUGIN_GGC_END' events (for which the callback -is called with a null 'gcc_data') to be notified of the start or end of -the GCC garbage collection. - - Some plugins may need to have GGC mark additional data. This can be -done by registering a callback (called with a null 'gcc_data') for the -'PLUGIN_GGC_MARKING' event. Such callbacks can call the 'ggc_set_mark' -routine, preferably through the 'ggc_mark' macro (and conversely, these -routines should usually not be used in plugins outside of the -'PLUGIN_GGC_MARKING' event). - - Some plugins may need to add extra GGC root tables, e.g. to handle -their own 'GTY'-ed data. This can be done with the -'PLUGIN_REGISTER_GGC_ROOTS' pseudo-event with a null callback and the -extra root table (of type 'struct ggc_root_tab*') as 'user_data'. -Plugins that want to use the 'if_marked' hash table option can add the -extra GGC cache tables generated by 'gengtype' using the -'PLUGIN_REGISTER_GGC_CACHES' pseudo-event with a null callback and the -extra cache table (of type 'struct ggc_cache_tab*') as 'user_data'. -Running the 'gengtype -p SOURCE-DIR FILE-LIST PLUGIN*.C ...' utility -generates these extra root tables. - - You should understand the details of memory management inside GCC -before using 'PLUGIN_GGC_MARKING', 'PLUGIN_REGISTER_GGC_ROOTS' or -'PLUGIN_REGISTER_GGC_CACHES'. - - -File: gccint.info, Node: Plugins description, Next: Plugins attr, Prev: Plugins GC, Up: Plugins - -23.5 Giving information about a plugin -====================================== - -A plugin should give some information to the user about itself. This -uses the following structure: - - struct plugin_info - { - const char *version; - const char *help; - }; - - Such a structure is passed as the 'user_data' by the plugin's init -routine using 'register_callback' with the 'PLUGIN_INFO' pseudo-event -and a null callback. - - -File: gccint.info, Node: Plugins attr, Next: Plugins recording, Prev: Plugins description, Up: Plugins - -23.6 Registering custom attributes or pragmas -============================================= - -For analysis (or other) purposes it is useful to be able to add custom -attributes or pragmas. - - The 'PLUGIN_ATTRIBUTES' callback is called during attribute -registration. Use the 'register_attribute' function to register custom -attributes. - - /* Attribute handler callback */ - static tree - handle_user_attribute (tree *node, tree name, tree args, - int flags, bool *no_add_attrs) - { - return NULL_TREE; - } - - /* Attribute definition */ - static struct attribute_spec user_attr = - { "user", 1, 1, false, false, false, handle_user_attribute, false }; - - /* Plugin callback called during attribute registration. - Registered with register_callback (plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL) - */ - static void - register_attributes (void *event_data, void *data) - { - warning (0, G_("Callback to register attributes")); - register_attribute (&user_attr); - } - - The PLUGIN_PRAGMAS callback is called once during pragmas registration. -Use the 'c_register_pragma', 'c_register_pragma_with_data', -'c_register_pragma_with_expansion', -'c_register_pragma_with_expansion_and_data' functions to register custom -pragmas and their handlers (which often want to call 'pragma_lex') from -'c-family/c-pragma.h'. - - /* Plugin callback called during pragmas registration. Registered with - register_callback (plugin_name, PLUGIN_PRAGMAS, - register_my_pragma, NULL); - */ - static void - register_my_pragma (void *event_data, void *data) - { - warning (0, G_("Callback to register pragmas")); - c_register_pragma ("GCCPLUGIN", "sayhello", handle_pragma_sayhello); - } - - It is suggested to pass '"GCCPLUGIN"' (or a short name identifying your -plugin) as the "space" argument of your pragma. - - Pragmas registered with 'c_register_pragma_with_expansion' or -'c_register_pragma_with_expansion_and_data' support preprocessor -expansions. For example: - - #define NUMBER 10 - #pragma GCCPLUGIN foothreshold (NUMBER) - - -File: gccint.info, Node: Plugins recording, Next: Plugins gate, Prev: Plugins attr, Up: Plugins - -23.7 Recording information about pass execution -=============================================== - -The event PLUGIN_PASS_EXECUTION passes the pointer to the executed pass -(the same as current_pass) as 'gcc_data' to the callback. You can also -inspect cfun to find out about which function this pass is executed for. -Note that this event will only be invoked if the gate check (if -applicable, modified by PLUGIN_OVERRIDE_GATE) succeeds. You can use -other hooks, like 'PLUGIN_ALL_PASSES_START', 'PLUGIN_ALL_PASSES_END', -'PLUGIN_ALL_IPA_PASSES_START', 'PLUGIN_ALL_IPA_PASSES_END', -'PLUGIN_EARLY_GIMPLE_PASSES_START', and/or -'PLUGIN_EARLY_GIMPLE_PASSES_END' to manipulate global state in your -plugin(s) in order to get context for the pass execution. - - -File: gccint.info, Node: Plugins gate, Next: Plugins tracking, Prev: Plugins recording, Up: Plugins - -23.8 Controlling which passes are being run -=========================================== - -After the original gate function for a pass is called, its result - the -gate status - is stored as an integer. Then the event -'PLUGIN_OVERRIDE_GATE' is invoked, with a pointer to the gate status in -the 'gcc_data' parameter to the callback function. A nonzero value of -the gate status means that the pass is to be executed. You can both -read and write the gate status via the passed pointer. - - -File: gccint.info, Node: Plugins tracking, Next: Plugins building, Prev: Plugins gate, Up: Plugins - -23.9 Keeping track of available passes -====================================== - -When your plugin is loaded, you can inspect the various pass lists to -determine what passes are available. However, other plugins might add -new passes. Also, future changes to GCC might cause generic passes to -be added after plugin loading. When a pass is first added to one of the -pass lists, the event 'PLUGIN_NEW_PASS' is invoked, with the callback -parameter 'gcc_data' pointing to the new pass. - - -File: gccint.info, Node: Plugins building, Prev: Plugins tracking, Up: Plugins - -23.10 Building GCC plugins -========================== - -If plugins are enabled, GCC installs the headers needed to build a -plugin (somewhere in the installation tree, e.g. under '/usr/local'). -In particular a 'plugin/include' directory is installed, containing all -the header files needed to build plugins. - - On most systems, you can query this 'plugin' directory by invoking 'gcc --print-file-name=plugin' (replace if needed 'gcc' with the appropriate -program path). - - Inside plugins, this 'plugin' directory name can be queried by calling -'default_plugin_dir_name ()'. - - Plugins may know, when they are compiled, the GCC version for which -'plugin-version.h' is provided. The constant macros -'GCCPLUGIN_VERSION_MAJOR', 'GCCPLUGIN_VERSION_MINOR', -'GCCPLUGIN_VERSION_PATCHLEVEL', 'GCCPLUGIN_VERSION' are integer numbers, -so a plugin could ensure it is built for GCC 4.7 with - #if GCCPLUGIN_VERSION != 4007 - #error this GCC plugin is for GCC 4.7 - #endif - - The following GNU Makefile excerpt shows how to build a simple plugin: - - HOST_GCC=g++ - TARGET_GCC=gcc - PLUGIN_SOURCE_FILES= plugin1.c plugin2.cc - GCCPLUGINS_DIR:= $(shell $(TARGET_GCC) -print-file-name=plugin) - CXXFLAGS+= -I$(GCCPLUGINS_DIR)/include -fPIC -fno-rtti -O2 - - plugin.so: $(PLUGIN_SOURCE_FILES) - $(HOST_GCC) -shared $(CXXFLAGS) $^ -o $@ - - A single source file plugin may be built with 'g++ -I`gcc --print-file-name=plugin`/include -fPIC -shared -fno-rtti -O2 plugin.c -o -plugin.so', using backquote shell syntax to query the 'plugin' -directory. - - When a plugin needs to use 'gengtype', be sure that both 'gengtype' and -'gtype.state' have the same version as the GCC for which the plugin is -built. - - -File: gccint.info, Node: LTO, Next: Funding, Prev: Plugins, Up: Top - -24 Link Time Optimization -************************* - -Link Time Optimization (LTO) gives GCC the capability of dumping its -internal representation (GIMPLE) to disk, so that all the different -compilation units that make up a single executable can be optimized as a -single module. This expands the scope of inter-procedural optimizations -to encompass the whole program (or, rather, everything that is visible -at link time). - -* Menu: - -* LTO Overview:: Overview of LTO. -* LTO object file layout:: LTO file sections in ELF. -* IPA:: Using summary information in IPA passes. -* WHOPR:: Whole program assumptions, - linker plugin and symbol visibilities. -* Internal flags:: Internal flags controlling 'lto1'. - - -File: gccint.info, Node: LTO Overview, Next: LTO object file layout, Up: LTO - -24.1 Design Overview -==================== - -Link time optimization is implemented as a GCC front end for a bytecode -representation of GIMPLE that is emitted in special sections of '.o' -files. Currently, LTO support is enabled in most ELF-based systems, as -well as darwin, cygwin and mingw systems. - - Since GIMPLE bytecode is saved alongside final object code, object -files generated with LTO support are larger than regular object files. -This "fat" object format makes it easy to integrate LTO into existing -build systems, as one can, for instance, produce archives of the files. -Additionally, one might be able to ship one set of fat objects which -could be used both for development and the production of optimized -builds. A, perhaps surprising, side effect of this feature is that any -mistake in the toolchain that leads to LTO information not being used -(e.g. an older 'libtool' calling 'ld' directly). This is both an -advantage, as the system is more robust, and a disadvantage, as the user -is not informed that the optimization has been disabled. - - The current implementation only produces "fat" objects, effectively -doubling compilation time and increasing file sizes up to 5x the -original size. This hides the problem that some tools, such as 'ar' and -'nm', need to understand symbol tables of LTO sections. These tools -were extended to use the plugin infrastructure, and with these problems -solved, GCC will also support "slim" objects consisting of the -intermediate code alone. - - At the highest level, LTO splits the compiler in two. The first half -(the "writer") produces a streaming representation of all the internal -data structures needed to optimize and generate code. This includes -declarations, types, the callgraph and the GIMPLE representation of -function bodies. - - When '-flto' is given during compilation of a source file, the pass -manager executes all the passes in 'all_lto_gen_passes'. Currently, -this phase is composed of two IPA passes: - - * 'pass_ipa_lto_gimple_out' This pass executes the function - 'lto_output' in 'lto-streamer-out.c', which traverses the call - graph encoding every reachable declaration, type and function. - This generates a memory representation of all the file sections - described below. - - * 'pass_ipa_lto_finish_out' This pass executes the function - 'produce_asm_for_decls' in 'lto-streamer-out.c', which takes the - memory image built in the previous pass and encodes it in the - corresponding ELF file sections. - - The second half of LTO support is the "reader". This is implemented as -the GCC front end 'lto1' in 'lto/lto.c'. When 'collect2' detects a link -set of '.o'/'.a' files with LTO information and the '-flto' is enabled, -it invokes 'lto1' which reads the set of files and aggregates them into -a single translation unit for optimization. The main entry point for -the reader is 'lto/lto.c':'lto_main'. - -24.1.1 LTO modes of operation ------------------------------ - -One of the main goals of the GCC link-time infrastructure was to allow -effective compilation of large programs. For this reason GCC implements -two link-time compilation modes. - - 1. _LTO mode_, in which the whole program is read into the compiler at - link-time and optimized in a similar way as if it were a single - source-level compilation unit. - - 2. _WHOPR or partitioned mode_, designed to utilize multiple CPUs - and/or a distributed compilation environment to quickly link large - applications. WHOPR stands for WHOle Program optimizeR (not to be - confused with the semantics of '-fwhole-program'). It partitions - the aggregated callgraph from many different '.o' files and - distributes the compilation of the sub-graphs to different CPUs. - - Note that distributed compilation is not implemented yet, but since - the parallelism is facilitated via generating a 'Makefile', it - would be easy to implement. - - WHOPR splits LTO into three main stages: - 1. Local generation (LGEN) This stage executes in parallel. Every - file in the program is compiled into the intermediate language and - packaged together with the local call-graph and summary - information. This stage is the same for both the LTO and WHOPR - compilation mode. - - 2. Whole Program Analysis (WPA) WPA is performed sequentially. The - global call-graph is generated, and a global analysis procedure - makes transformation decisions. The global call-graph is - partitioned to facilitate parallel optimization during phase 3. - The results of the WPA stage are stored into new object files which - contain the partitions of program expressed in the intermediate - language and the optimization decisions. - - 3. Local transformations (LTRANS) This stage executes in parallel. - All the decisions made during phase 2 are implemented locally in - each partitioned object file, and the final object code is - generated. Optimizations which cannot be decided efficiently - during the phase 2 may be performed on the local call-graph - partitions. - - WHOPR can be seen as an extension of the usual LTO mode of compilation. -In LTO, WPA and LTRANS are executed within a single execution of the -compiler, after the whole program has been read into memory. - - When compiling in WHOPR mode, the callgraph is partitioned during the -WPA stage. The whole program is split into a given number of partitions -of roughly the same size. The compiler tries to minimize the number of -references which cross partition boundaries. The main advantage of -WHOPR is to allow the parallel execution of LTRANS stages, which are the -most time-consuming part of the compilation process. Additionally, it -avoids the need to load the whole program into memory. - - -File: gccint.info, Node: LTO object file layout, Next: IPA, Prev: LTO Overview, Up: LTO - -24.2 LTO file sections -====================== - -LTO information is stored in several ELF sections inside object files. -Data structures and enum codes for sections are defined in -'lto-streamer.h'. - - These sections are emitted from 'lto-streamer-out.c' and mapped in all -at once from 'lto/lto.c':'lto_file_read'. The individual functions -dealing with the reading/writing of each section are described below. - - * Command line options ('.gnu.lto_.opts') - - This section contains the command line options used to generate the - object files. This is used at link time to determine the - optimization level and other settings when they are not explicitly - specified at the linker command line. - - Currently, GCC does not support combining LTO object files compiled - with different set of the command line options into a single - binary. At link time, the options given on the command line and - the options saved on all the files in a link-time set are applied - globally. No attempt is made at validating the combination of - flags (other than the usual validation done by option processing). - This is implemented in 'lto/lto.c':'lto_read_all_file_options'. - - * Symbol table ('.gnu.lto_.symtab') - - This table replaces the ELF symbol table for functions and - variables represented in the LTO IL. Symbols used and exported by - the optimized assembly code of "fat" objects might not match the - ones used and exported by the intermediate code. This table is - necessary because the intermediate code is less optimized and thus - requires a separate symbol table. - - Additionally, the binary code in the "fat" object will lack a call - to a function, since the call was optimized out at compilation time - after the intermediate language was streamed out. In some special - cases, the same optimization may not happen during link-time - optimization. This would lead to an undefined symbol if only one - symbol table was used. - - The symbol table is emitted in - 'lto-streamer-out.c':'produce_symtab'. - - * Global declarations and types ('.gnu.lto_.decls') - - This section contains an intermediate language dump of all - declarations and types required to represent the callgraph, static - variables and top-level debug info. - - The contents of this section are emitted in - 'lto-streamer-out.c':'produce_asm_for_decls'. Types and symbols - are emitted in a topological order that preserves the sharing of - pointers when the file is read back in - ('lto.c':'read_cgraph_and_symbols'). - - * The callgraph ('.gnu.lto_.cgraph') - - This section contains the basic data structure used by the GCC - inter-procedural optimization infrastructure. This section stores - an annotated multi-graph which represents the functions and call - sites as well as the variables, aliases and top-level 'asm' - statements. - - This section is emitted in 'lto-streamer-out.c':'output_cgraph' and - read in 'lto-cgraph.c':'input_cgraph'. - - * IPA references ('.gnu.lto_.refs') - - This section contains references between function and static - variables. It is emitted by 'lto-cgraph.c':'output_refs' and read - by 'lto-cgraph.c':'input_refs'. - - * Function bodies ('.gnu.lto_.function_body.<name>') - - This section contains function bodies in the intermediate language - representation. Every function body is in a separate section to - allow copying of the section independently to different object - files or reading the function on demand. - - Functions are emitted in 'lto-streamer-out.c':'output_function' and - read in 'lto-streamer-in.c':'input_function'. - - * Static variable initializers ('.gnu.lto_.vars') - - This section contains all the symbols in the global variable pool. - It is emitted by 'lto-cgraph.c':'output_varpool' and read in - 'lto-cgraph.c':'input_cgraph'. - - * Summaries and optimization summaries used by IPA passes - ('.gnu.lto_.<xxx>', where '<xxx>' is one of 'jmpfuncs', 'pureconst' - or 'reference') - - These sections are used by IPA passes that need to emit summary - information during LTO generation to be read and aggregated at link - time. Each pass is responsible for implementing two pass manager - hooks: one for writing the summary and another for reading it in. - The format of these sections is entirely up to each individual - pass. The only requirement is that the writer and reader hooks - agree on the format. - - -File: gccint.info, Node: IPA, Next: WHOPR, Prev: LTO object file layout, Up: LTO - -24.3 Using summary information in IPA passes -============================================ - -Programs are represented internally as a _callgraph_ (a multi-graph -where nodes are functions and edges are call sites) and a _varpool_ (a -list of static and external variables in the program). - - The inter-procedural optimization is organized as a sequence of -individual passes, which operate on the callgraph and the varpool. To -make the implementation of WHOPR possible, every inter-procedural -optimization pass is split into several stages that are executed at -different times during WHOPR compilation: - - * LGEN time - 1. _Generate summary_ ('generate_summary' in 'struct - ipa_opt_pass_d'). This stage analyzes every function body and - variable initializer is examined and stores relevant - information into a pass-specific data structure. - - 2. _Write summary_ ('write_summary' in 'struct ipa_opt_pass_d'). - This stage writes all the pass-specific information generated - by 'generate_summary'. Summaries go into their own - 'LTO_section_*' sections that have to be declared in - 'lto-streamer.h':'enum lto_section_type'. A new section is - created by calling 'create_output_block' and data can be - written using the 'lto_output_*' routines. - - * WPA time - 1. _Read summary_ ('read_summary' in 'struct ipa_opt_pass_d'). - This stage reads all the pass-specific information in exactly - the same order that it was written by 'write_summary'. - - 2. _Execute_ ('execute' in 'struct opt_pass'). This performs - inter-procedural propagation. This must be done without - actual access to the individual function bodies or variable - initializers. Typically, this results in a transitive closure - operation over the summary information of all the nodes in the - callgraph. - - 3. _Write optimization summary_ ('write_optimization_summary' in - 'struct ipa_opt_pass_d'). This writes the result of the - inter-procedural propagation into the object file. This can - use the same data structures and helper routines used in - 'write_summary'. - - * LTRANS time - 1. _Read optimization summary_ ('read_optimization_summary' in - 'struct ipa_opt_pass_d'). The counterpart to - 'write_optimization_summary'. This reads the interprocedural - optimization decisions in exactly the same format emitted by - 'write_optimization_summary'. - - 2. _Transform_ ('function_transform' and 'variable_transform' in - 'struct ipa_opt_pass_d'). The actual function bodies and - variable initializers are updated based on the information - passed down from the _Execute_ stage. - - The implementation of the inter-procedural passes are shared between -LTO, WHOPR and classic non-LTO compilation. - - * During the traditional file-by-file mode every pass executes its - own _Generate summary_, _Execute_, and _Transform_ stages within - the single execution context of the compiler. - - * In LTO compilation mode, every pass uses _Generate summary_ and - _Write summary_ stages at compilation time, while the _Read - summary_, _Execute_, and _Transform_ stages are executed at link - time. - - * In WHOPR mode all stages are used. - - To simplify development, the GCC pass manager differentiates between -normal inter-procedural passes and small inter-procedural passes. A -_small inter-procedural pass_ ('SIMPLE_IPA_PASS') is a pass that does -everything at once and thus it can not be executed during WPA in WHOPR -mode. It defines only the _Execute_ stage and during this stage it -accesses and modifies the function bodies. Such passes are useful for -optimization at LGEN or LTRANS time and are used, for example, to -implement early optimization before writing object files. The simple -inter-procedural passes can also be used for easier prototyping and -development of a new inter-procedural pass. - -24.3.1 Virtual clones ---------------------- - -One of the main challenges of introducing the WHOPR compilation mode was -addressing the interactions between optimization passes. In LTO -compilation mode, the passes are executed in a sequence, each of which -consists of analysis (or _Generate summary_), propagation (or _Execute_) -and _Transform_ stages. Once the work of one pass is finished, the next -pass sees the updated program representation and can execute. This -makes the individual passes dependent on each other. - - In WHOPR mode all passes first execute their _Generate summary_ stage. -Then summary writing marks the end of the LGEN stage. At WPA time, the -summaries are read back into memory and all passes run the _Execute_ -stage. Optimization summaries are streamed and sent to LTRANS, where -all the passes execute the _Transform_ stage. - - Most optimization passes split naturally into analysis, propagation and -transformation stages. But some do not. The main problem arises when -one pass performs changes and the following pass gets confused by seeing -different callgraphs between the _Transform_ stage and the _Generate -summary_ or _Execute_ stage. This means that the passes are required to -communicate their decisions with each other. - - To facilitate this communication, the GCC callgraph infrastructure -implements _virtual clones_, a method of representing the changes -performed by the optimization passes in the callgraph without needing to -update function bodies. - - A _virtual clone_ in the callgraph is a function that has no associated -body, just a description of how to create its body based on a different -function (which itself may be a virtual clone). - - The description of function modifications includes adjustments to the -function's signature (which allows, for example, removing or adding -function arguments), substitutions to perform on the function body, and, -for inlined functions, a pointer to the function that it will be inlined -into. - - It is also possible to redirect any edge of the callgraph from a -function to its virtual clone. This implies updating of the call site -to adjust for the new function signature. - - Most of the transformations performed by inter-procedural optimizations -can be represented via virtual clones. For instance, a constant -propagation pass can produce a virtual clone of the function which -replaces one of its arguments by a constant. The inliner can represent -its decisions by producing a clone of a function whose body will be -later integrated into a given function. - - Using _virtual clones_, the program can be easily updated during the -_Execute_ stage, solving most of pass interactions problems that would -otherwise occur during _Transform_. - - Virtual clones are later materialized in the LTRANS stage and turned -into real functions. Passes executed after the virtual clone were -introduced also perform their _Transform_ stage on new functions, so for -a pass there is no significant difference between operating on a real -function or a virtual clone introduced before its _Execute_ stage. - - Optimization passes then work on virtual clones introduced before their -_Execute_ stage as if they were real functions. The only difference is -that clones are not visible during the _Generate Summary_ stage. - - To keep function summaries updated, the callgraph interface allows an -optimizer to register a callback that is called every time a new clone -is introduced as well as when the actual function or variable is -generated or when a function or variable is removed. These hooks are -registered in the _Generate summary_ stage and allow the pass to keep -its information intact until the _Execute_ stage. The same hooks can -also be registered during the _Execute_ stage to keep the optimization -summaries updated for the _Transform_ stage. - -24.3.2 IPA references ---------------------- - -GCC represents IPA references in the callgraph. For a function or -variable 'A', the _IPA reference_ is a list of all locations where the -address of 'A' is taken and, when 'A' is a variable, a list of all -direct stores and reads to/from 'A'. References represent an oriented -multi-graph on the union of nodes of the callgraph and the varpool. See -'ipa-reference.c':'ipa_reference_write_optimization_summary' and -'ipa-reference.c':'ipa_reference_read_optimization_summary' for details. - -24.3.3 Jump functions ---------------------- - -Suppose that an optimization pass sees a function 'A' and it knows the -values of (some of) its arguments. The _jump function_ describes the -value of a parameter of a given function call in function 'A' based on -this knowledge. - - Jump functions are used by several optimizations, such as the -inter-procedural constant propagation pass and the devirtualization -pass. The inliner also uses jump functions to perform inlining of -callbacks. - - -File: gccint.info, Node: WHOPR, Next: Internal flags, Prev: IPA, Up: LTO - -24.4 Whole program assumptions, linker plugin and symbol visibilities -===================================================================== - -Link-time optimization gives relatively minor benefits when used alone. -The problem is that propagation of inter-procedural information does not -work well across functions and variables that are called or referenced -by other compilation units (such as from a dynamically linked library). -We say that such functions and variables are _externally visible_. - - To make the situation even more difficult, many applications organize -themselves as a set of shared libraries, and the default ELF visibility -rules allow one to overwrite any externally visible symbol with a -different symbol at runtime. This basically disables any optimizations -across such functions and variables, because the compiler cannot be sure -that the function body it is seeing is the same function body that will -be used at runtime. Any function or variable not declared 'static' in -the sources degrades the quality of inter-procedural optimization. - - To avoid this problem the compiler must assume that it sees the whole -program when doing link-time optimization. Strictly speaking, the whole -program is rarely visible even at link-time. Standard system libraries -are usually linked dynamically or not provided with the link-time -information. In GCC, the whole program option ('-fwhole-program') -asserts that every function and variable defined in the current -compilation unit is static, except for function 'main' (note: at link -time, the current unit is the union of all objects compiled with LTO). -Since some functions and variables need to be referenced externally, for -example by another DSO or from an assembler file, GCC also provides the -function and variable attribute 'externally_visible' which can be used -to disable the effect of '-fwhole-program' on a specific symbol. - - The whole program mode assumptions are slightly more complex in C++, -where inline functions in headers are put into _COMDAT_ sections. -COMDAT function and variables can be defined by multiple object files -and their bodies are unified at link-time and dynamic link-time. COMDAT -functions are changed to local only when their address is not taken and -thus un-sharing them with a library is not harmful. COMDAT variables -always remain externally visible, however for readonly variables it is -assumed that their initializers cannot be overwritten by a different -value. - - GCC provides the function and variable attribute 'visibility' that can -be used to specify the visibility of externally visible symbols (or -alternatively an '-fdefault-visibility' command line option). ELF -defines the 'default', 'protected', 'hidden' and 'internal' -visibilities. - - The most commonly used is visibility is 'hidden'. It specifies that -the symbol cannot be referenced from outside of the current shared -library. Unfortunately, this information cannot be used directly by the -link-time optimization in the compiler since the whole shared library -also might contain non-LTO objects and those are not visible to the -compiler. - - GCC solves this problem using linker plugins. A _linker plugin_ is an -interface to the linker that allows an external program to claim the -ownership of a given object file. The linker then performs the linking -procedure by querying the plugin about the symbol table of the claimed -objects and once the linking decisions are complete, the plugin is -allowed to provide the final object file before the actual linking is -made. The linker plugin obtains the symbol resolution information which -specifies which symbols provided by the claimed objects are bound from -the rest of a binary being linked. - - Currently, the linker plugin works only in combination with the Gold -linker, but a GNU ld implementation is under development. - - GCC is designed to be independent of the rest of the toolchain and aims -to support linkers without plugin support. For this reason it does not -use the linker plugin by default. Instead, the object files are -examined by 'collect2' before being passed to the linker and objects -found to have LTO sections are passed to 'lto1' first. This mode does -not work for library archives. The decision on what object files from -the archive are needed depends on the actual linking and thus GCC would -have to implement the linker itself. The resolution information is -missing too and thus GCC needs to make an educated guess based on -'-fwhole-program'. Without the linker plugin GCC also assumes that -symbols are declared 'hidden' and not referred by non-LTO code by -default. - - -File: gccint.info, Node: Internal flags, Prev: WHOPR, Up: LTO - -24.5 Internal flags controlling 'lto1' -====================================== - -The following flags are passed into 'lto1' and are not meant to be used -directly from the command line. - - * -fwpa This option runs the serial part of the link-time optimizer - performing the inter-procedural propagation (WPA mode). The - compiler reads in summary information from all inputs and performs - an analysis based on summary information only. It generates object - files for subsequent runs of the link-time optimizer where - individual object files are optimized using both summary - information from the WPA mode and the actual function bodies. It - then drives the LTRANS phase. - - * -fltrans This option runs the link-time optimizer in the - local-transformation (LTRANS) mode, which reads in output from a - previous run of the LTO in WPA mode. In the LTRANS mode, LTO - optimizes an object and produces the final assembly. - - * -fltrans-output-list=FILE This option specifies a file to which the - names of LTRANS output files are written. This option is only - meaningful in conjunction with '-fwpa'. - - * -fresolution=FILE This option specifies the linker resolution file. - This option is only meaningful in conjunction with '-fwpa' and as - option to pass through to the LTO linker plugin. - - -File: gccint.info, Node: Funding, Next: GNU Project, Prev: LTO, Up: Top - -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. 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If the - Program specifies that a certain numbered version of the GNU - General Public License "or any later version" applies to it, you - have the option of following the terms and conditions either of - that numbered version or of any later version published by the Free - Software Foundation. If the Program does not specify a version - number of the GNU General Public License, you may choose any - version ever published by the Free Software Foundation. - - If the Program specifies that a proxy can decide which future - versions of the GNU General Public License can be used, that - proxy's public statement of acceptance of a version permanently - authorizes you to choose that version for the Program. - - Later license versions may give you additional or different - permissions. However, no additional obligations are imposed on any - author or copyright holder as a result of your choosing to follow a - later version. - - 15. Disclaimer of Warranty. - - 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. - - 16. 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Interpretation of Sections 15 and 16. - - If the disclaimer of warranty and limitation of liability provided - above cannot be given local legal effect according to their terms, - reviewing courts shall apply local law that most closely - approximates an absolute waiver of all civil liability in - connection with the Program, unless a warranty or assumption of - liability accompanies a copy of the Program in return for a fee. - -END OF TERMS AND CONDITIONS -=========================== - -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 state -the exclusion of warranty; and each file should have at least the -"copyright" line and a pointer to where the full notice is found. - - ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. - Copyright (C) YEAR 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 3 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, see <http://www.gnu.org/licenses/>. - - Also add information on how to contact you by electronic and paper -mail. - - If the program does terminal interaction, make it output a short notice -like this when it starts in an interactive mode: - - PROGRAM Copyright (C) YEAR NAME OF AUTHOR - This program 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. - - The hypothetical commands 'show w' and 'show c' should show the -appropriate parts of the General Public License. Of course, your -program's commands might be different; for a GUI interface, you would -use an "about box". - - You should also get your employer (if you work as a programmer) or -school, if any, to sign a "copyright disclaimer" for the program, if -necessary. For more information on this, and how to apply and follow -the GNU GPL, see <http://www.gnu.org/licenses/>. - - The GNU 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 Lesser General Public License instead of this License. But first, -please read <http://www.gnu.org/philosophy/why-not-lgpl.html>. - - -File: gccint.info, Node: GNU Free Documentation License, Next: Contributors, Prev: Copying, Up: Top - -GNU Free Documentation License -****************************** - - Version 1.3, 3 November 2008 - - Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. - <http://fsf.org/> - - Everyone is permitted to copy and distribute verbatim copies - of this license document, but changing it is not allowed. - - 0. PREAMBLE - - The purpose of this License is to make a manual, textbook, or other - functional and useful document "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. - It complements the GNU General Public License, which is a copyleft - license designed for free software. - - We have designed this License in order to use it for manuals for - free software, because free software needs free documentation: a - free program should come with manuals providing the same freedoms - that the software does. But this License is not limited to - software manuals; it can be used for any textual work, regardless - of subject matter or whether it is published as a printed book. We - recommend this License principally for works whose purpose is - instruction or reference. - - 1. APPLICABILITY AND DEFINITIONS - - This License applies to any manual or other work, in any medium, - that contains a notice placed by the copyright holder saying it can - be distributed under the terms of this License. Such a notice - grants a world-wide, royalty-free license, unlimited in duration, - to use that work under the conditions stated herein. The - "Document", below, refers to any such manual or work. Any member - of the public is a licensee, and is addressed as "you". You accept - the license if you copy, modify or distribute the work in a way - requiring permission under copyright law. - - A "Modified Version" of the Document means any work containing the - Document or a portion of it, either copied verbatim, or with - modifications and/or translated into another language. - - A "Secondary Section" is a named appendix or a front-matter section - of the Document that deals exclusively with the relationship of the - publishers or authors of the Document to the Document's overall - subject (or to related matters) and contains nothing that could - fall directly within that overall subject. (Thus, if the Document - is in part a textbook of mathematics, a Secondary Section may not - explain any mathematics.) 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A copy that is not - "Transparent" is called "Opaque". - - Examples of suitable formats for Transparent copies include plain - ASCII without markup, Texinfo input format, LaTeX input format, - SGML or XML using a publicly available DTD, and standard-conforming - simple HTML, PostScript or PDF designed for human modification. - Examples of transparent image formats include PNG, XCF and JPG. - Opaque formats include proprietary formats that can be read and - edited only by proprietary word processors, SGML or XML for which - the DTD and/or processing tools are not generally available, and - the machine-generated HTML, PostScript or PDF produced by some word - processors for output purposes only. - - The "Title Page" means, for a printed book, the title page itself, - plus such following pages as are needed to hold, legibly, the - material this License requires to appear in the title page. For - works in formats which do not have any title page as such, "Title - Page" means the text near the most prominent appearance of the - work's title, preceding the beginning of the body of the text. - - The "publisher" means any person or entity that distributes copies - of the Document to the public. - - A section "Entitled XYZ" means a named subunit of the Document - whose title either is precisely XYZ or contains XYZ in parentheses - following text that translates XYZ in another language. (Here XYZ - stands for a specific section name mentioned below, such as - "Acknowledgements", "Dedications", "Endorsements", or "History".) - To "Preserve the Title" of such a section when you modify the - Document means that it remains a section "Entitled XYZ" according - to this definition. - - The Document may include Warranty Disclaimers next to the notice - which states that this License applies to the Document. These - Warranty Disclaimers are considered to be included by reference in - this License, but only as regards disclaiming warranties: any other - implication that these Warranty Disclaimers may have is void and - has no effect on the meaning of this License. - - 2. VERBATIM COPYING - - You may copy and distribute the Document in any medium, either - commercially or noncommercially, provided that this License, the - copyright notices, and the license notice saying this License - applies to the Document are reproduced in all copies, and that you - add no other conditions whatsoever to those of this License. You - may not use technical measures to obstruct or control the reading - or further copying of the copies you make or distribute. However, - you may accept compensation in exchange for copies. If you - distribute a large enough number of copies you must also follow the - conditions in section 3. - - You may also lend copies, under the same conditions stated above, - and you may publicly display copies. - - 3. COPYING IN QUANTITY - - If you publish printed copies (or copies in media that commonly - have printed covers) of the Document, numbering more than 100, and - the Document's license notice requires Cover Texts, you must - enclose the copies in covers that carry, clearly and legibly, all - these Cover Texts: Front-Cover Texts on the front cover, and - Back-Cover Texts on the back cover. Both covers must also clearly - and legibly identify you as the publisher of these copies. The - front cover must present the full title with all words of the title - equally prominent and visible. You may add other material on the - covers in addition. Copying with changes limited to the covers, as - long as they preserve the title of the Document and satisfy these - conditions, can be treated as verbatim copying in other respects. - - If the required texts for either cover are too voluminous to fit - legibly, you should put the first ones listed (as many as fit - reasonably) on the actual cover, and continue the rest onto - adjacent pages. - - If you publish or distribute Opaque copies of the Document - numbering more than 100, you must either include a machine-readable - Transparent copy along with each Opaque copy, or state in or with - each Opaque copy a computer-network location from which the general - network-using public has access to download using public-standard - network protocols a complete Transparent copy of the Document, free - of added material. If you use the latter option, you must take - reasonably prudent steps, when you begin distribution of Opaque - copies in quantity, to ensure that this Transparent copy will - remain thus accessible at the stated location until at least one - year after the last time you distribute an Opaque copy (directly or - through your agents or retailers) of that edition to the public. - - It is requested, but not required, that you contact the authors of - the Document well before redistributing any large number of copies, - to give them a chance to provide you with an updated version of the - Document. - - 4. MODIFICATIONS - - You may copy and distribute a Modified Version of the Document - under the conditions of sections 2 and 3 above, provided that you - release the Modified Version under precisely this License, with the - Modified Version filling the role of the Document, thus licensing - distribution and modification of the Modified Version to whoever - possesses a copy of it. In addition, you must do these things in - the Modified Version: - - A. Use in the Title Page (and on the covers, if any) a title - distinct from that of the Document, and from those of previous - versions (which should, if there were any, be listed in the - History section of the Document). You may use the same title - as a previous version if the original publisher of that - version gives permission. - - B. 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. - - C. State on the Title page the name of the publisher of the - Modified Version, as the publisher. - - D. Preserve all the copyright notices of the Document. - - E. Add an appropriate copyright notice for your modifications - adjacent to the other copyright notices. - - F. 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. - - G. Preserve in that license notice the full lists of Invariant - Sections and required Cover Texts given in the Document's - license notice. - - H. Include an unaltered copy of this License. - - I. 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. - - J. 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. - - K. 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. - - L. 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. - - M. Delete any section Entitled "Endorsements". Such a section - may not be included in the Modified Version. - - N. Do not retitle any existing section to be Entitled - "Endorsements" or to conflict in title with any Invariant - Section. - - O. Preserve any Warranty Disclaimers. - - 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. - - 5. 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." - - 6. 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. - - 7. 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. - - 8. 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A copy of the license is included in the section entitled ``GNU - Free Documentation License''. - - If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, -replace the "with...Texts." line with this: - - with the Invariant Sections being LIST THEIR TITLES, with - the Front-Cover Texts being LIST, and with the Back-Cover Texts - being LIST. - - 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. - - -File: gccint.info, Node: Contributors, Next: Option Index, Prev: GNU Free Documentation License, Up: Top - -Contributors to GCC -******************* - -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 -<law@redhat.com> or <gerald@pfeifer.com> if you have been left out or -some of your contributions are not listed. Please keep this list in -alphabetical order. - - * Analog Devices helped implement the support for complex data types - and iterators. - - * John David Anglin for threading-related fixes and improvements to - libstdc++-v3, and the HP-UX port. - - * James van Artsdalen wrote the code that makes efficient use of the - Intel 80387 register stack. - - * Abramo and Roberto Bagnara for the SysV68 Motorola 3300 Delta - Series port. - - * Alasdair Baird for various bug fixes. - - * Giovanni Bajo for analyzing lots of complicated C++ problem - reports. - - * Peter Barada for his work to improve code generation for new - ColdFire cores. - - * Gerald Baumgartner added the signature extension to the C++ front - end. - - * Godmar Back for his Java improvements and encouragement. - - * Scott Bambrough for help porting the Java compiler. - - * Wolfgang Bangerth for processing tons of bug reports. - - * Jon Beniston for his Microsoft Windows port of Java and port to - Lattice Mico32. - - * Daniel Berlin for better DWARF2 support, faster/better - optimizations, improved alias analysis, plus migrating GCC to - Bugzilla. - - * Geoff Berry for his Java object serialization work and various - patches. - - * David Binderman tests weekly snapshots of GCC trunk against Fedora - Rawhide for several architectures. - - * Uros Bizjak for the implementation of x87 math built-in functions - and for various middle end and i386 back end improvements and bug - fixes. - - * Eric Blake for helping to make GCJ and libgcj conform to the - specifications. - - * Janne Blomqvist for contributions to GNU Fortran. - - * Segher Boessenkool for various fixes. - - * Hans-J. Boehm for his garbage collector, IA-64 libffi port, and - other Java work. - - * Neil Booth for work on cpplib, lang hooks, debug hooks and other - miscellaneous clean-ups. - - * Steven Bosscher for integrating the GNU Fortran front end into GCC - and for contributing to the tree-ssa branch. - - * Eric Botcazou for fixing middle- and backend bugs left and right. - - * 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. - - * Devon Bowen helped port GCC to the Tahoe. - - * Don Bowman for mips-vxworks contributions. - - * Dave Brolley for work on cpplib and Chill. - - * Paul Brook for work on the ARM architecture and maintaining GNU - Fortran. - - * Robert Brown implemented the support for Encore 32000 systems. - - * Christian Bruel for improvements to local store elimination. - - * Herman A.J. ten Brugge for various fixes. - - * Joerg Brunsmann for Java compiler hacking and help with the GCJ - FAQ. - - * Joe Buck for his direction via the steering committee. - - * Craig Burley for leadership of the G77 Fortran effort. - - * Stephan Buys for contributing Doxygen notes for libstdc++. - - * 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. - - * John Carr for his alias work, SPARC hacking, infrastructure - improvements, previous contributions to the steering committee, - loop optimizations, etc. - - * Stephane Carrez for 68HC11 and 68HC12 ports. - - * Steve Chamberlain for support for the Renesas SH and H8 processors - and the PicoJava processor, and for GCJ config fixes. - - * Glenn Chambers for help with the GCJ FAQ. - - * John-Marc Chandonia for various libgcj patches. - - * Denis Chertykov for contributing and maintaining the AVR port, the - first GCC port for an 8-bit architecture. - - * Scott Christley for his Objective-C contributions. - - * Eric Christopher for his Java porting help and clean-ups. - - * Branko Cibej for more warning contributions. - - * The GNU Classpath project for all of their merged runtime code. - - * Nick Clifton for arm, mcore, fr30, v850, m32r, msp430 rx work, - '--help', and other random hacking. - - * Michael Cook for libstdc++ cleanup patches to reduce warnings. - - * R. Kelley Cook for making GCC buildable from a read-only directory - as well as other miscellaneous build process and documentation - clean-ups. - - * Ralf Corsepius for SH testing and minor bug fixing. - - * Stan Cox for care and feeding of the x86 port and lots of behind - the scenes hacking. - - * Alex Crain provided changes for the 3b1. - - * Ian Dall for major improvements to the NS32k port. - - * Paul Dale for his work to add uClinux platform support to the m68k - backend. - - * Dario Dariol contributed the four varieties of sample programs that - print a copy of their source. - - * Russell Davidson for fstream and stringstream fixes in libstdc++. - - * Bud Davis for work on the G77 and GNU Fortran compilers. - - * Mo DeJong for GCJ and libgcj bug fixes. - - * DJ Delorie for the DJGPP port, build and libiberty maintenance, - various bug fixes, and the M32C, MeP, MSP430, and RL78 ports. - - * Arnaud Desitter for helping to debug GNU Fortran. - - * Gabriel Dos Reis for contributions to G++, contributions and - maintenance of GCC diagnostics infrastructure, libstdc++-v3, - including 'valarray<>', 'complex<>', maintaining the numerics - library (including that pesky '<limits>' :-) and keeping up-to-date - anything to do with numbers. - - * 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 'complex<>', sanity checking and - disbursement, configuration architecture, libio maintenance, and - early math work. - - * Franc,ois Dumont for his work on libstdc++-v3, especially - maintaining and improving 'debug-mode' and associative and - unordered containers. - - * Zdenek Dvorak for a new loop unroller and various fixes. - - * Michael Eager for his work on the Xilinx MicroBlaze port. - - * Richard Earnshaw for his ongoing work with the ARM. - - * 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. - - * Kevin Ediger for the floating point formatting of num_put::do_put - in libstdc++. - - * 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. - - * Paul Eggert for random hacking all over GCC. - - * Mark Elbrecht for various DJGPP improvements, and for libstdc++ - configuration support for locales and fstream-related fixes. - - * Vadim Egorov for libstdc++ fixes in strings, streambufs, and - iostreams. - - * Christian Ehrhardt for dealing with bug reports. - - * Ben Elliston for his work to move the Objective-C runtime into its - own subdirectory and for his work on autoconf. - - * Revital Eres for work on the PowerPC 750CL port. - - * Marc Espie for OpenBSD support. - - * Doug Evans for much of the global optimization framework, arc, - m32r, and SPARC work. - - * 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. - - * Fred Fish for BeOS support and Ada fixes. - - * Ivan Fontes Garcia for the Portuguese translation of the GCJ FAQ. - - * Peter Gerwinski for various bug fixes and the Pascal front end. - - * Kaveh R. Ghazi for his direction via the steering committee, - amazing work to make '-W -Wall -W* -Werror' useful, and testing GCC - on a plethora of platforms. Kaveh extends his gratitude to the - CAIP Center at Rutgers University for providing him with computing - resources to work on Free Software from the late 1980s to 2010. - - * John Gilmore for a donation to the FSF earmarked improving GNU - Java. - - * Judy Goldberg for c++ contributions. - - * 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. - - * Anthony Green for his '-Os' contributions, the moxie port, and Java - front end work. - - * Stu Grossman for gdb hacking, allowing GCJ developers to debug Java - code. - - * Michael K. Gschwind contributed the port to the PDP-11. - - * Richard Biener for his ongoing middle-end contributions and bug - fixes and for release management. - - * Ron Guilmette implemented the 'protoize' and '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. - - * Sumanth Gundapaneni for contributing the CR16 port. - - * Mostafa Hagog for Swing Modulo Scheduling (SMS) and post reload - GCSE. - - * Bruno Haible for improvements in the runtime overhead for EH, new - warnings and assorted bug fixes. - - * Andrew Haley for his amazing Java compiler and library efforts. - - * Chris Hanson assisted in making GCC work on HP-UX for the 9000 - series 300. - - * 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. - - * Dara Hazeghi for wading through myriads of target-specific bug - reports. - - * Kate Hedstrom for staking the G77 folks with an initial testsuite. - - * 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. - - * Aldy Hernandez for working on the PowerPC port, SIMD support, and - various fixes. - - * Nobuyuki Hikichi of Software Research Associates, Tokyo, - contributed the support for the Sony NEWS machine. - - * Kazu Hirata for caring and feeding the Renesas H8/300 port and - various fixes. - - * Katherine Holcomb for work on GNU Fortran. - - * Manfred Hollstein for his ongoing work to keep the m88k alive, lots - of testing and bug fixing, particularly of GCC configury code. - - * Steve Holmgren for MachTen patches. - - * Mat Hostetter for work on the TILE-Gx and TILEPro ports. - - * Jan Hubicka for his x86 port improvements. - - * Falk Hueffner for working on C and optimization bug reports. - - * Bernardo Innocenti for his m68k work, including merging of ColdFire - improvements and uClinux support. - - * Christian Iseli for various bug fixes. - - * Kamil Iskra for general m68k hacking. - - * Lee Iverson for random fixes and MIPS testing. - - * Andreas Jaeger for testing and benchmarking of GCC and various bug - fixes. - - * 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. - - * Janis Johnson for ia64 testing and fixes, her quality improvement - sidetracks, and web page maintenance. - - * Kean Johnston for SCO OpenServer support and various fixes. - - * Tim Josling for the sample language treelang based originally on - Richard Kenner's "toy" language. - - * Nicolai Josuttis for additional libstdc++ documentation. - - * Klaus Kaempf for his ongoing work to make alpha-vms a viable - target. - - * Steven G. Kargl for work on GNU Fortran. - - * David Kashtan of SRI adapted GCC to VMS. - - * Ryszard Kabatek for many, many libstdc++ bug fixes and - optimizations of strings, especially member functions, and for - auto_ptr fixes. - - * Geoffrey Keating for his ongoing work to make the PPC work for - GNU/Linux and his automatic regression tester. - - * Brendan Kehoe for his ongoing work with G++ and for a lot of early - work in just about every part of libstdc++. - - * Oliver M. Kellogg of Deutsche Aerospace contributed the port to the - MIL-STD-1750A. - - * 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. - - * 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. - - * Robin Kirkham for cpu32 support. - - * Mark Klein for PA improvements. - - * Thomas Koenig for various bug fixes. - - * Bruce Korb for the new and improved fixincludes code. - - * Benjamin Kosnik for his G++ work and for leading the libstdc++-v3 - effort. - - * Charles LaBrec contributed the support for the Integrated Solutions - 68020 system. - - * Asher Langton and Mike Kumbera for contributing Cray pointer - support to GNU Fortran, and for other GNU Fortran improvements. - - * 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. - - * Walter Lee for work on the TILE-Gx and TILEPro ports. - - * Marc Lehmann for his direction via the steering committee and - helping with analysis and improvements of x86 performance. - - * Victor Leikehman for work on GNU Fortran. - - * Ted Lemon wrote parts of the RTL reader and printer. - - * Kriang Lerdsuwanakij for C++ improvements including template as - template parameter support, and many C++ fixes. - - * Warren Levy for tremendous work on libgcj (Java Runtime Library) - and random work on the Java front end. - - * Alain Lichnewsky ported GCC to the MIPS CPU. - - * Oskar Liljeblad for hacking on AWT and his many Java bug reports - and patches. - - * Robert Lipe for OpenServer support, new testsuites, testing, etc. - - * Chen Liqin for various S+core related fixes/improvement, and for - maintaining the S+core port. - - * Weiwen Liu for testing and various bug fixes. - - * Manuel Lo'pez-Iba'n~ez for improving '-Wconversion' and many other - diagnostics fixes and improvements. - - * Dave Love for his ongoing work with the Fortran front end and - runtime libraries. - - * Martin von Lo"wis for internal consistency checking infrastructure, - various C++ improvements including namespace support, and tons of - assistance with libstdc++/compiler merges. - - * H.J. Lu for his previous contributions to the steering committee, - many x86 bug reports, prototype patches, and keeping the GNU/Linux - ports working. - - * Greg McGary for random fixes and (someday) bounded pointers. - - * Andrew MacLeod for his ongoing work in building a real EH system, - various code generation improvements, work on the global optimizer, - etc. - - * 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. - - * Bob Manson for his behind the scenes work on dejagnu. - - * Philip Martin for lots of libstdc++ string and vector iterator - fixes and improvements, and string clean up and testsuites. - - * All of the Mauve project contributors, for Java test code. - - * Bryce McKinlay for numerous GCJ and libgcj fixes and improvements. - - * Adam Megacz for his work on the Microsoft Windows port of GCJ. - - * Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS, - powerpc, haifa, ECOFF debug support, and other assorted hacking. - - * Jason Merrill for his direction via the steering committee and - leading the G++ effort. - - * Martin Michlmayr for testing GCC on several architectures using the - entire Debian archive. - - * David Miller for his direction via the steering committee, lots of - SPARC work, improvements in jump.c and interfacing with the Linux - kernel developers. - - * Gary Miller ported GCC to Charles River Data Systems machines. - - * Alfred Minarik for libstdc++ string and ios bug fixes, and turning - the entire libstdc++ testsuite namespace-compatible. - - * Mark Mitchell for his direction via the steering committee, - mountains of C++ work, load/store hoisting out of loops, alias - analysis improvements, ISO C 'restrict' support, and serving as - release manager from 2000 to 2011. - - * Alan Modra for various GNU/Linux bits and testing. - - * Toon Moene for his direction via the steering committee, Fortran - maintenance, and his ongoing work to make us make Fortran run fast. - - * 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... - difficult. - - * Catherine Moore for fixing various ugly problems we have sent her - way, including the haifa bug which was killing the Alpha & PowerPC - Linux kernels. - - * Mike Moreton for his various Java patches. - - * David Mosberger-Tang for various Alpha improvements, and for the - initial IA-64 port. - - * 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. - - * Bill Moyer for his behind the scenes work on various issues. - - * Philippe De Muyter for his work on the m68k port. - - * 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. - - * 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. - - * Felix Natter for documentation on porting libstdc++. - - * Nathanael Nerode for cleaning up the configuration/build process. - - * NeXT, Inc. donated the front end that supports the Objective-C - language. - - * Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to the - search engine setup, various documentation fixes and other small - fixes. - - * Geoff Noer for his work on getting cygwin native builds working. - - * Diego Novillo for his work on Tree SSA, OpenMP, SPEC performance - tracking web pages, GIMPLE tuples, and assorted fixes. - - * David O'Brien for the FreeBSD/alpha, FreeBSD/AMD x86-64, - FreeBSD/ARM, FreeBSD/PowerPC, and FreeBSD/SPARC64 ports and related - infrastructure improvements. - - * Alexandre Oliva for various build infrastructure improvements, - scripts and amazing testing work, including keeping libtool issues - sane and happy. - - * Stefan Olsson for work on mt_alloc. - - * Melissa O'Neill for various NeXT fixes. - - * 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, and maintaining the IRIX, - Solaris 2, and Tru64 UNIX ports. - - * Hartmut Penner for work on the s390 port. - - * Paul Petersen wrote the machine description for the Alliant FX/8. - - * Alexandre Petit-Bianco for implementing much of the Java compiler - and continued Java maintainership. - - * Matthias Pfaller for major improvements to the NS32k port. - - * 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. - - * Andrew Pinski for processing bug reports by the dozen. - - * Ovidiu Predescu for his work on the Objective-C front end and - runtime libraries. - - * Jerry Quinn for major performance improvements in C++ formatted - I/O. - - * Ken Raeburn for various improvements to checker, MIPS ports and - various cleanups in the compiler. - - * Rolf W. Rasmussen for hacking on AWT. - - * David Reese of Sun Microsystems contributed to the Solaris on - PowerPC port. - - * Volker Reichelt for keeping up with the problem reports. - - * Joern Rennecke for maintaining the sh port, loop, regmove & reload - hacking and developing and maintaining the Epiphany port. - - * 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. - - * Craig Rodrigues for processing tons of bug reports. - - * Ola Ro"nnerup for work on mt_alloc. - - * Gavin Romig-Koch for lots of behind the scenes MIPS work. - - * 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 'g77-0.5.16/f/DOC' file. - - * Ken Rose for fixes to GCC's delay slot filling code. - - * Paul Rubin wrote most of the preprocessor. - - * Pe'tur Runo'lfsson for major performance improvements in C++ - formatted I/O and large file support in C++ filebuf. - - * Chip Salzenberg for libstdc++ patches and improvements to locales, - traits, Makefiles, libio, libtool hackery, and "long long" support. - - * Juha Sarlin for improvements to the H8 code generator. - - * Greg Satz assisted in making GCC work on HP-UX for the 9000 series - 300. - - * Roger Sayle for improvements to constant folding and GCC's RTL - optimizers as well as for fixing numerous bugs. - - * Bradley Schatz for his work on the GCJ FAQ. - - * Peter Schauer wrote the code to allow debugging to work on the - Alpha. - - * William Schelter did most of the work on the Intel 80386 support. - - * Tobias Schlu"ter for work on GNU Fortran. - - * Bernd Schmidt for various code generation improvements and major - work in the reload pass, serving as release manager for GCC 2.95.3, - and work on the Blackfin and C6X ports. - - * 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. - - * Jason Schroeder for jcf-dump patches. - - * Andreas Schwab for his work on the m68k port. - - * Lars Segerlund for work on GNU Fortran. - - * Dodji Seketeli for numerous C++ bug fixes and debug info - improvements. - - * Tim Shen for major work on '<regex>'. - - * Joel Sherrill for his direction via the steering committee, RTEMS - contributions and RTEMS testing. - - * Nathan Sidwell for many C++ fixes/improvements. - - * 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. - - * Kenny Simpson for prompting libstdc++ fixes due to defect reports - from the LWG (thereby keeping GCC in line with updates from the - ISO). - - * Franz Sirl for his ongoing work with making the PPC port stable for - GNU/Linux. - - * Andrey Slepuhin for assorted AIX hacking. - - * Trevor Smigiel for contributing the SPU port. - - * Christopher Smith did the port for Convex machines. - - * Danny Smith for his major efforts on the Mingw (and Cygwin) ports. - - * Randy Smith finished the Sun FPA support. - - * Ed Smith-Rowland for his continuous work on libstdc++-v3, special - functions, '<random>', and various improvements to C++11 features. - - * 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 'INTEGER*1', 'INTEGER*2', and - 'LOGICAL*1'. - - * Zdenek Sojka for running automated regression testing of GCC and - reporting numerous bugs. - - * Jayant Sonar for contributing the CR16 port. - - * Brad Spencer for contributions to the GLIBCPP_FORCE_NEW technique. - - * Richard Stallman, for writing the original GCC and launching the - GNU project. - - * Jan Stein of the Chalmers Computer Society provided support for - Genix, as well as part of the 32000 machine description. - - * Nigel Stephens for various mips16 related fixes/improvements. - - * Jonathan Stone wrote the machine description for the Pyramid - computer. - - * Graham Stott for various infrastructure improvements. - - * John Stracke for his Java HTTP protocol fixes. - - * Mike Stump for his Elxsi port, G++ contributions over the years and - more recently his vxworks contributions - - * Jeff Sturm for Java porting help, bug fixes, and encouragement. - - * Shigeya Suzuki for this fixes for the bsdi platforms. - - * Ian Lance Taylor for the Go frontend, the initial mips16 and mips64 - support, general configury hacking, fixincludes, etc. - - * Holger Teutsch provided the support for the Clipper CPU. - - * Gary Thomas for his ongoing work to make the PPC work for - GNU/Linux. - - * Philipp Thomas for random bug fixes throughout the compiler - - * Jason Thorpe for thread support in libstdc++ on NetBSD. - - * Kresten Krab Thorup wrote the run time support for the Objective-C - language and the fantastic Java bytecode interpreter. - - * 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. - - * Andreas Tobler for his work porting libgcj to Darwin. - - * Teemu Torma for thread safe exception handling support. - - * Leonard Tower wrote parts of the parser, RTL generator, and RTL - definitions, and of the VAX machine description. - - * Daniel Towner and Hariharan Sandanagobalane contributed and - maintain the picoChip port. - - * Tom Tromey for internationalization support and for his many Java - contributions and libgcj maintainership. - - * Lassi Tuura for improvements to config.guess to determine HP - processor types. - - * Petter Urkedal for libstdc++ CXXFLAGS, math, and algorithms fixes. - - * Andy Vaught for the design and initial implementation of the GNU - Fortran front end. - - * Brent Verner for work with the libstdc++ cshadow files and their - associated configure steps. - - * Todd Vierling for contributions for NetBSD ports. - - * Jonathan Wakely for contributing libstdc++ Doxygen notes and XHTML - guidance. - - * Dean Wakerley for converting the install documentation from HTML to - texinfo in time for GCC 3.0. - - * Krister Walfridsson for random bug fixes. - - * Feng Wang for contributions to GNU Fortran. - - * 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. Also, for starting and driving the - '<regex>' effort. - - * 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. - - * Ulrich Weigand for work on the s390 port. - - * Zack Weinberg for major work on cpplib and various other bug fixes. - - * Matt Welsh for help with Linux Threads support in GCJ. - - * Urban Widmark for help fixing java.io. - - * Mark Wielaard for new Java library code and his work integrating - with Classpath. - - * Dale Wiles helped port GCC to the Tahoe. - - * Bob Wilson from Tensilica, Inc. for the Xtensa port. - - * 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. - - * Paul Woegerer and Tal Agmon for the CRX port. - - * Carlo Wood for various fixes. - - * Tom Wood for work on the m88k port. - - * Chung-Ju Wu for his work on the Andes NDS32 port. - - * Canqun Yang for work on GNU Fortran. - - * Masanobu Yuhara of Fujitsu Laboratories implemented the machine - description for the Tron architecture (specifically, the Gmicro). - - * Kevin Zachmann helped port GCC to the Tahoe. - - * Ayal Zaks for Swing Modulo Scheduling (SMS). - - * Xiaoqiang Zhang for work on GNU Fortran. - - * Gilles Zunino for help porting Java to Irix. - - The following people are recognized for their contributions to GNAT, -the Ada front end of GCC: - * Bernard Banner - - * Romain Berrendonner - - * Geert Bosch - - * Emmanuel Briot - - * Joel Brobecker - - * Ben Brosgol - - * Vincent Celier - - * Arnaud Charlet - - * Chien Chieng - - * Cyrille Comar - - * Cyrille Crozes - - * Robert Dewar - - * Gary Dismukes - - * Robert Duff - - * Ed Falis - - * Ramon Fernandez - - * Sam Figueroa - - * Vasiliy Fofanov - - * Michael Friess - - * Franco Gasperoni - - * Ted Giering - - * Matthew Gingell - - * Laurent Guerby - - * Jerome Guitton - - * Olivier Hainque - - * Jerome Hugues - - * Hristian Kirtchev - - * Jerome Lambourg - - * Bruno Leclerc - - * Albert Lee - - * Sean McNeil - - * Javier Miranda - - * Laurent Nana - - * Pascal Obry - - * Dong-Ik Oh - - * Laurent Pautet - - * Brett Porter - - * Thomas Quinot - - * Nicolas Roche - - * Pat Rogers - - * Jose Ruiz - - * Douglas Rupp - - * Sergey Rybin - - * Gail Schenker - - * Ed Schonberg - - * Nicolas Setton - - * Samuel Tardieu - - The following people are recognized for their contributions of new -features, bug reports, testing and integration of classpath/libgcj for -GCC version 4.1: - * Lillian Angel for 'JTree' implementation and lots Free Swing - additions and bug fixes. - - * Wolfgang Baer for 'GapContent' bug fixes. - - * Anthony Balkissoon for 'JList', Free Swing 1.5 updates and mouse - event fixes, lots of Free Swing work including 'JTable' editing. - - * Stuart Ballard for RMI constant fixes. - - * Goffredo Baroncelli for 'HTTPURLConnection' fixes. - - * Gary Benson for 'MessageFormat' fixes. - - * Daniel Bonniot for 'Serialization' fixes. - - * Chris Burdess for lots of gnu.xml and http protocol fixes, 'StAX' - and 'DOM xml:id' support. - - * Ka-Hing Cheung for 'TreePath' and 'TreeSelection' fixes. - - * Archie Cobbs for build fixes, VM interface updates, - 'URLClassLoader' updates. - - * Kelley Cook for build fixes. - - * Martin Cordova for Suggestions for better 'SocketTimeoutException'. - - * David Daney for 'BitSet' bug fixes, 'HttpURLConnection' rewrite and - improvements. - - * 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 bug fixes. - - * Jeroen Frijters for 'ClassLoader' and nio cleanups, serialization - fixes, better 'Proxy' support, bug fixes and IKVM integration. - - * Santiago Gala for 'AccessControlContext' fixes. - - * Nicolas Geoffray for 'VMClassLoader' and 'AccessController' - improvements. - - * David Gilbert for 'basic' and 'metal' icon and plaf support and - lots of documenting, Lots of Free Swing and metal theme additions. - 'MetalIconFactory' implementation. - - * Anthony Green for 'MIDI' framework, 'ALSA' and 'DSSI' providers. - - * Andrew Haley for 'Serialization' and 'URLClassLoader' fixes, gcj - build speedups. - - * Kim Ho for 'JFileChooser' implementation. - - * Andrew John Hughes for 'Locale' and net fixes, URI RFC2986 updates, - 'Serialization' fixes, 'Properties' XML support and generic branch - work, VMIntegration guide update. - - * Bastiaan Huisman for 'TimeZone' bug fixing. - - * Andreas Jaeger for mprec updates. - - * Paul Jenner for better '-Werror' support. - - * Ito Kazumitsu for 'NetworkInterface' implementation and updates. - - * Roman Kennke for 'BoxLayout', 'GrayFilter' and 'SplitPane', plus - bug fixes all over. Lots of Free Swing work including styled text. - - * Simon Kitching for 'String' cleanups and optimization suggestions. - - * Michael Koch for configuration fixes, 'Locale' updates, bug and - build fixes. - - * Guilhem Lavaux for configuration, thread and channel fixes and - Kaffe integration. JCL native 'Pointer' updates. Logger bug - fixes. - - * David Lichteblau for JCL support library global/local reference - cleanups. - - * Aaron Luchko for JDWP updates and documentation fixes. - - * Ziga Mahkovec for 'Graphics2D' upgraded to Cairo 0.5 and new regex - features. - - * Sven de Marothy for BMP imageio support, CSS and 'TextLayout' - fixes. 'GtkImage' rewrite, 2D, awt, free swing and date/time fixes - and implementing the Qt4 peers. - - * Casey Marshall for crypto algorithm fixes, 'FileChannel' lock, - 'SystemLogger' and 'FileHandler' rotate implementations, NIO - 'FileChannel.map' support, security and policy updates. - - * Bryce McKinlay for RMI work. - - * Audrius Meskauskas for lots of Free Corba, RMI and HTML work plus - testing and documenting. - - * Kalle Olavi Niemitalo for build fixes. - - * Rainer Orth for build fixes. - - * Andrew Overholt for 'File' locking fixes. - - * Ingo Proetel for 'Image', 'Logger' and 'URLClassLoader' updates. - - * Olga Rodimina for 'MenuSelectionManager' implementation. - - * Jan Roehrich for 'BasicTreeUI' and 'JTree' fixes. - - * Julian Scheid for documentation updates and gjdoc support. - - * Christian Schlichtherle for zip fixes and cleanups. - - * Robert Schuster for documentation updates and beans fixes, - 'TreeNode' enumerations and 'ActionCommand' and various fixes, XML - and URL, AWT and Free Swing bug fixes. - - * Keith Seitz for lots of JDWP work. - - * Christian Thalinger for 64-bit cleanups, Configuration and VM - interface fixes and 'CACAO' integration, 'fdlibm' updates. - - * Gael Thomas for 'VMClassLoader' boot packages support suggestions. - - * Andreas Tobler for Darwin and Solaris testing and fixing, 'Qt4' - support for Darwin/OS X, 'Graphics2D' support, 'gtk+' updates. - - * Dalibor Topic for better 'DEBUG' support, build cleanups and Kaffe - integration. 'Qt4' build infrastructure, 'SHA1PRNG' and - 'GdkPixbugDecoder' updates. - - * Tom Tromey for Eclipse integration, generics work, lots of bug - fixes and gcj integration including coordinating The Big Merge. - - * Mark Wielaard for bug fixes, packaging and release management, - 'Clipboard' implementation, system call interrupts and network - timeouts and 'GdkPixpufDecoder' fixes. - - 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: - - * Michael Abd-El-Malek - - * Thomas Arend - - * Bonzo Armstrong - - * Steven Ashe - - * Chris Baldwin - - * David Billinghurst - - * Jim Blandy - - * Stephane Bortzmeyer - - * Horst von Brand - - * Frank Braun - - * Rodney Brown - - * Sidney Cadot - - * Bradford Castalia - - * Robert Clark - - * Jonathan Corbet - - * Ralph Doncaster - - * Richard Emberson - - * Levente Farkas - - * Graham Fawcett - - * Mark Fernyhough - - * Robert A. French - - * Jo"rgen Freyh - - * Mark K. Gardner - - * Charles-Antoine Gauthier - - * Yung Shing Gene - - * David Gilbert - - * Simon Gornall - - * Fred Gray - - * John Griffin - - * Patrik Hagglund - - * Phil Hargett - - * Amancio Hasty - - * Takafumi Hayashi - - * Bryan W. Headley - - * Kevin B. Hendricks - - * Joep Jansen - - * Christian Joensson - - * Michel Kern - - * David Kidd - - * Tobias Kuipers - - * Anand Krishnaswamy - - * A. O. V. Le Blanc - - * llewelly - - * Damon Love - - * Brad Lucier - - * Matthias Klose - - * Martin Knoblauch - - * Rick Lutowski - - * Jesse Macnish - - * Stefan Morrell - - * Anon A. Mous - - * Matthias Mueller - - * Pekka Nikander - - * Rick Niles - - * Jon Olson - - * Magnus Persson - - * Chris Pollard - - * Richard Polton - - * Derk Reefman - - * David Rees - - * Paul Reilly - - * Tom Reilly - - * Torsten Rueger - - * Danny Sadinoff - - * Marc Schifer - - * Erik Schnetter - - * Wayne K. Schroll - - * David Schuler - - * Vin Shelton - - * Tim Souder - - * Adam Sulmicki - - * Bill Thorson - - * George Talbot - - * Pedro A. M. Vazquez - - * Gregory Warnes - - * Ian Watson - - * David E. Young - - * And many others - - And finally we'd like to thank everyone who uses the compiler, provides -feedback and generally reminds us why we're doing this work in the first -place. - - -File: gccint.info, Node: Option Index, Next: Concept Index, Prev: Contributors, Up: Top - -Option Index -************ - -GCC's command line options are indexed here without any initial '-' or -'--'. Where an option has both positive and negative forms (such as -'-fOPTION' and '-fno-OPTION'), relevant entries in the manual are -indexed under the most appropriate form; it may sometimes be useful to -look up both forms. - - -* Menu: - -* fltrans: Internal flags. (line 18) -* fltrans-output-list: Internal flags. (line 23) -* fresolution: Internal flags. (line 27) -* fwpa: Internal flags. (line 9) -* msoft-float: Soft float library routines. - (line 6) - - -File: gccint.info, Node: Concept Index, Prev: Option Index, Up: Top - -Concept Index -************* - - -* Menu: - -* '!' in constraint: Multi-Alternative. (line 47) -* '#' in constraint: Modifiers. (line 67) -* '#' in template: Output Template. (line 66) -* #pragma: Misc. (line 387) -* '%' in constraint: Modifiers. (line 45) -* % in GTY option: GTY Options. (line 18) -* '%' in template: Output Template. (line 6) -* '&' in constraint: Modifiers. (line 25) -* (nil): RTL Objects. (line 73) -* '*' in constraint: Modifiers. (line 72) -* '*' in template: Output Statement. (line 29) -* '+' in constraint: Modifiers. (line 12) -* '-fsection-anchors': Special Accessors. (line 117) -* '-fsection-anchors' <1>: Anchored Addresses. (line 6) -* '/c' in RTL dump: Flags. (line 221) -* '/f' in RTL dump: Flags. (line 229) -* '/i' in RTL dump: Flags. (line 274) -* '/j' in RTL dump: Flags. (line 286) -* '/s' in RTL dump: Flags. (line 245) -* '/u' in RTL dump: Flags. (line 296) -* '/v' in RTL dump: Flags. (line 328) -* '0' in constraint: Simple Constraints. (line 128) -* '<' in constraint: Simple Constraints. (line 47) -* '=' in constraint: Modifiers. (line 8) -* '>' in constraint: Simple Constraints. (line 59) -* '?' in constraint: Multi-Alternative. (line 41) -* \: Output Template. (line 46) -* __absvdi2: Integer library routines. - (line 106) -* __absvsi2: Integer library routines. - (line 105) -* __addda3: Fixed-point fractional library routines. - (line 44) -* __adddf3: Soft float library routines. - (line 22) -* __adddq3: Fixed-point fractional library routines. - (line 31) -* __addha3: Fixed-point fractional library routines. - (line 41) -* __addhq3: Fixed-point fractional library routines. - (line 29) -* __addqq3: Fixed-point fractional library routines. - (line 27) -* __addsa3: Fixed-point fractional library routines. - (line 43) -* __addsf3: Soft float library routines. - (line 21) -* __addsq3: Fixed-point fractional library routines. - (line 30) -* __addta3: Fixed-point fractional library routines. - (line 45) -* __addtf3: Soft float library routines. - (line 23) -* __adduda3: Fixed-point fractional library routines. - (line 51) -* __addudq3: Fixed-point fractional library routines. - (line 39) -* __adduha3: Fixed-point fractional library routines. - (line 47) -* __adduhq3: Fixed-point fractional library routines. - (line 35) -* __adduqq3: Fixed-point fractional library routines. - (line 33) -* __addusa3: Fixed-point fractional library routines. - (line 49) -* __addusq3: Fixed-point fractional library routines. - (line 37) -* __adduta3: Fixed-point fractional library routines. - (line 53) -* __addvdi3: Integer library routines. - (line 110) -* __addvsi3: Integer library routines. - (line 109) -* __addxf3: Soft float library routines. - (line 25) -* __ashlda3: Fixed-point fractional library routines. - (line 350) -* __ashldi3: Integer library routines. - (line 13) -* __ashldq3: Fixed-point fractional library routines. - (line 338) -* __ashlha3: Fixed-point fractional library routines. - (line 348) -* __ashlhq3: Fixed-point fractional library routines. - (line 336) -* __ashlqq3: Fixed-point fractional library routines. - (line 335) -* __ashlsa3: Fixed-point fractional library routines. - (line 349) -* __ashlsi3: Integer library routines. - (line 12) -* __ashlsq3: Fixed-point fractional library routines. - (line 337) -* __ashlta3: Fixed-point fractional library routines. - (line 351) -* __ashlti3: Integer library routines. - (line 14) -* __ashluda3: Fixed-point fractional library routines. - (line 357) -* __ashludq3: Fixed-point fractional library routines. - (line 346) -* __ashluha3: Fixed-point fractional library routines. - (line 353) -* __ashluhq3: Fixed-point fractional library routines. - (line 342) -* __ashluqq3: Fixed-point fractional library routines. - (line 340) -* __ashlusa3: Fixed-point fractional library routines. - (line 355) -* __ashlusq3: Fixed-point fractional library routines. - (line 344) -* __ashluta3: Fixed-point fractional library routines. - (line 359) -* __ashrda3: Fixed-point fractional library routines. - (line 370) -* __ashrdi3: Integer library routines. - (line 18) -* __ashrdq3: Fixed-point fractional library routines. - (line 366) -* __ashrha3: Fixed-point fractional library routines. - (line 368) -* __ashrhq3: Fixed-point fractional library routines. - (line 364) -* __ashrqq3: Fixed-point fractional library routines. - (line 363) -* __ashrsa3: Fixed-point fractional library routines. - (line 369) -* __ashrsi3: Integer library routines. - (line 17) -* __ashrsq3: Fixed-point fractional library routines. - (line 365) -* __ashrta3: Fixed-point fractional library routines. - (line 371) -* __ashrti3: Integer library routines. - (line 19) -* __bid_adddd3: Decimal float library routines. - (line 23) -* __bid_addsd3: Decimal float library routines. - (line 19) -* __bid_addtd3: Decimal float library routines. - (line 27) -* __bid_divdd3: Decimal float library routines. - (line 66) -* __bid_divsd3: Decimal float library routines. - (line 62) -* __bid_divtd3: Decimal float library routines. - (line 70) -* __bid_eqdd2: Decimal float library routines. - (line 258) -* __bid_eqsd2: Decimal float library routines. - (line 256) -* __bid_eqtd2: Decimal float library routines. - (line 260) -* __bid_extendddtd2: Decimal float library routines. - (line 91) -* __bid_extendddtf: Decimal float library routines. - (line 139) -* __bid_extendddxf: Decimal float library routines. - (line 133) -* __bid_extenddfdd: Decimal float library routines. - (line 146) -* __bid_extenddftd: Decimal float library routines. - (line 106) -* __bid_extendsddd2: Decimal float library routines. - (line 87) -* __bid_extendsddf: Decimal float library routines. - (line 127) -* __bid_extendsdtd2: Decimal float library routines. - (line 89) -* __bid_extendsdtf: Decimal float library routines. - (line 137) -* __bid_extendsdxf: Decimal float library routines. - (line 131) -* __bid_extendsfdd: Decimal float library routines. - (line 102) -* __bid_extendsfsd: Decimal float library routines. - (line 144) -* __bid_extendsftd: Decimal float library routines. - (line 104) -* __bid_extendtftd: Decimal float library routines. - (line 148) -* __bid_extendxftd: Decimal float library routines. - (line 108) -* __bid_fixdddi: Decimal float library routines. - (line 169) -* __bid_fixddsi: Decimal float library routines. - (line 161) -* __bid_fixsddi: Decimal float library routines. - (line 167) -* __bid_fixsdsi: Decimal float library routines. - (line 159) -* __bid_fixtddi: Decimal float library routines. - (line 171) -* __bid_fixtdsi: Decimal float library routines. - (line 163) -* __bid_fixunsdddi: Decimal float library routines. - (line 186) -* __bid_fixunsddsi: Decimal float library routines. - (line 177) -* __bid_fixunssddi: Decimal float library routines. - (line 184) -* __bid_fixunssdsi: Decimal float library routines. - (line 175) -* __bid_fixunstddi: Decimal float library routines. - (line 188) -* __bid_fixunstdsi: Decimal float library routines. - (line 179) -* __bid_floatdidd: Decimal float library routines. - (line 204) -* __bid_floatdisd: Decimal float library routines. - (line 202) -* __bid_floatditd: Decimal float library routines. - (line 206) -* __bid_floatsidd: Decimal float library routines. - (line 195) -* __bid_floatsisd: Decimal float library routines. - (line 193) -* __bid_floatsitd: Decimal float library routines. - (line 197) -* __bid_floatunsdidd: Decimal float library routines. - (line 222) -* __bid_floatunsdisd: Decimal float library routines. - (line 220) -* __bid_floatunsditd: Decimal float library routines. - (line 224) -* __bid_floatunssidd: Decimal float library routines. - (line 213) -* __bid_floatunssisd: Decimal float library routines. - (line 211) -* __bid_floatunssitd: Decimal float library routines. - (line 215) -* __bid_gedd2: Decimal float library routines. - (line 276) -* __bid_gesd2: Decimal float library routines. - (line 274) -* __bid_getd2: Decimal float library routines. - (line 278) -* __bid_gtdd2: Decimal float library routines. - (line 303) -* __bid_gtsd2: Decimal float library routines. - (line 301) -* __bid_gttd2: Decimal float library routines. - (line 305) -* __bid_ledd2: Decimal float library routines. - (line 294) -* __bid_lesd2: Decimal float library routines. - (line 292) -* __bid_letd2: Decimal float library routines. - (line 296) -* __bid_ltdd2: Decimal float library routines. - (line 285) -* __bid_ltsd2: Decimal float library routines. - (line 283) -* __bid_lttd2: Decimal float library routines. - (line 287) -* __bid_muldd3: Decimal float library routines. - (line 52) -* __bid_mulsd3: Decimal float library routines. - (line 48) -* __bid_multd3: Decimal float library routines. - (line 56) -* __bid_nedd2: Decimal float library routines. - (line 267) -* __bid_negdd2: Decimal float library routines. - (line 77) -* __bid_negsd2: Decimal float library routines. - (line 75) -* __bid_negtd2: Decimal float library routines. - (line 79) -* __bid_nesd2: Decimal float library routines. - (line 265) -* __bid_netd2: Decimal float library routines. - (line 269) -* __bid_subdd3: Decimal float library routines. - (line 37) -* __bid_subsd3: Decimal float library routines. - (line 33) -* __bid_subtd3: Decimal float library routines. - (line 41) -* __bid_truncdddf: Decimal float library routines. - (line 152) -* __bid_truncddsd2: Decimal float library routines. - (line 93) -* __bid_truncddsf: Decimal float library routines. - (line 123) -* __bid_truncdfsd: Decimal float library routines. - (line 110) -* __bid_truncsdsf: Decimal float library routines. - (line 150) -* __bid_trunctddd2: Decimal float library routines. - (line 97) -* __bid_trunctddf: Decimal float library routines. - (line 129) -* __bid_trunctdsd2: Decimal float library routines. - (line 95) -* __bid_trunctdsf: Decimal float library routines. - (line 125) -* __bid_trunctdtf: Decimal float library routines. - (line 154) -* __bid_trunctdxf: Decimal float library routines. - (line 135) -* __bid_trunctfdd: Decimal float library routines. - (line 118) -* __bid_trunctfsd: Decimal float library routines. - (line 114) -* __bid_truncxfdd: Decimal float library routines. - (line 116) -* __bid_truncxfsd: Decimal float library routines. - (line 112) -* __bid_unorddd2: Decimal float library routines. - (line 234) -* __bid_unordsd2: Decimal float library routines. - (line 232) -* __bid_unordtd2: Decimal float library routines. - (line 236) -* __bswapdi2: Integer library routines. - (line 161) -* __bswapsi2: Integer library routines. - (line 160) -* __builtin_classify_type: Varargs. (line 48) -* __builtin_next_arg: Varargs. (line 39) -* __builtin_saveregs: Varargs. (line 22) -* __clear_cache: Miscellaneous routines. - (line 9) -* __clzdi2: Integer library routines. - (line 130) -* __clzsi2: Integer library routines. - (line 129) -* __clzti2: Integer library routines. - (line 131) -* __cmpda2: Fixed-point fractional library routines. - (line 450) -* __cmpdf2: Soft float library routines. - (line 163) -* __cmpdi2: Integer library routines. - (line 86) -* __cmpdq2: Fixed-point fractional library routines. - (line 439) -* __cmpha2: Fixed-point fractional library routines. - (line 448) -* __cmphq2: Fixed-point fractional library routines. - (line 437) -* __cmpqq2: Fixed-point fractional library routines. - (line 436) -* __cmpsa2: Fixed-point fractional library routines. - (line 449) -* __cmpsf2: Soft float library routines. - (line 162) -* __cmpsq2: Fixed-point fractional library routines. - (line 438) -* __cmpta2: Fixed-point fractional library routines. - (line 451) -* __cmptf2: Soft float library routines. - (line 164) -* __cmpti2: Integer library routines. - (line 87) -* __cmpuda2: Fixed-point fractional library routines. - (line 456) -* __cmpudq2: Fixed-point fractional library routines. - (line 446) -* __cmpuha2: Fixed-point fractional library routines. - (line 453) -* __cmpuhq2: Fixed-point fractional library routines. - (line 443) -* __cmpuqq2: Fixed-point fractional library routines. - (line 441) -* __cmpusa2: Fixed-point fractional library routines. - (line 455) -* __cmpusq2: Fixed-point fractional library routines. - (line 444) -* __cmputa2: Fixed-point fractional library routines. - (line 458) -* __CTOR_LIST__: Initialization. (line 25) -* __ctzdi2: Integer library routines. - (line 137) -* __ctzsi2: Integer library routines. - (line 136) -* __ctzti2: Integer library routines. - (line 138) -* __divda3: Fixed-point fractional library routines. - (line 226) -* __divdc3: Soft float library routines. - (line 250) -* __divdf3: Soft float library routines. - (line 47) -* __divdi3: Integer library routines. - (line 24) -* __divdq3: Fixed-point fractional library routines. - (line 221) -* __divha3: Fixed-point fractional library routines. - (line 223) -* __divhq3: Fixed-point fractional library routines. - (line 219) -* __divqq3: Fixed-point fractional library routines. - (line 217) -* __divsa3: Fixed-point fractional library routines. - (line 225) -* __divsc3: Soft float library routines. - (line 248) -* __divsf3: Soft float library routines. - (line 46) -* __divsi3: Integer library routines. - (line 23) -* __divsq3: Fixed-point fractional library routines. - (line 220) -* __divta3: Fixed-point fractional library routines. - (line 227) -* __divtc3: Soft float library routines. - (line 252) -* __divtf3: Soft float library routines. - (line 48) -* __divti3: Integer library routines. - (line 25) -* __divxc3: Soft float library routines. - (line 254) -* __divxf3: Soft float library routines. - (line 50) -* __dpd_adddd3: Decimal float library routines. - (line 21) -* __dpd_addsd3: Decimal float library routines. - (line 17) -* __dpd_addtd3: Decimal float library routines. - (line 25) -* __dpd_divdd3: Decimal float library routines. - (line 64) -* __dpd_divsd3: Decimal float library routines. - (line 60) -* __dpd_divtd3: Decimal float library routines. - (line 68) -* __dpd_eqdd2: Decimal float library routines. - (line 257) -* __dpd_eqsd2: Decimal float library routines. - (line 255) -* __dpd_eqtd2: Decimal float library routines. - (line 259) -* __dpd_extendddtd2: Decimal float library routines. - (line 90) -* __dpd_extendddtf: Decimal float library routines. - (line 138) -* __dpd_extendddxf: Decimal float library routines. - (line 132) -* __dpd_extenddfdd: Decimal float library routines. - (line 145) -* __dpd_extenddftd: Decimal float library routines. - (line 105) -* __dpd_extendsddd2: Decimal float library routines. - (line 86) -* __dpd_extendsddf: Decimal float library routines. - (line 126) -* __dpd_extendsdtd2: Decimal float library routines. - (line 88) -* __dpd_extendsdtf: Decimal float library routines. - (line 136) -* __dpd_extendsdxf: Decimal float library routines. - (line 130) -* __dpd_extendsfdd: Decimal float library routines. - (line 101) -* __dpd_extendsfsd: Decimal float library routines. - (line 143) -* __dpd_extendsftd: Decimal float library routines. - (line 103) -* __dpd_extendtftd: Decimal float library routines. - (line 147) -* __dpd_extendxftd: Decimal float library routines. - (line 107) -* __dpd_fixdddi: Decimal float library routines. - (line 168) -* __dpd_fixddsi: Decimal float library routines. - (line 160) -* __dpd_fixsddi: Decimal float library routines. - (line 166) -* __dpd_fixsdsi: Decimal float library routines. - (line 158) -* __dpd_fixtddi: Decimal float library routines. - (line 170) -* __dpd_fixtdsi: Decimal float library routines. - (line 162) -* __dpd_fixunsdddi: Decimal float library routines. - (line 185) -* __dpd_fixunsddsi: Decimal float library routines. - (line 176) -* __dpd_fixunssddi: Decimal float library routines. - (line 183) -* __dpd_fixunssdsi: Decimal float library routines. - (line 174) -* __dpd_fixunstddi: Decimal float library routines. - (line 187) -* __dpd_fixunstdsi: Decimal float library routines. - (line 178) -* __dpd_floatdidd: Decimal float library routines. - (line 203) -* __dpd_floatdisd: Decimal float library routines. - (line 201) -* __dpd_floatditd: Decimal float library routines. - (line 205) -* __dpd_floatsidd: Decimal float library routines. - (line 194) -* __dpd_floatsisd: Decimal float library routines. - (line 192) -* __dpd_floatsitd: Decimal float library routines. - (line 196) -* __dpd_floatunsdidd: Decimal float library routines. - (line 221) -* __dpd_floatunsdisd: Decimal float library routines. - (line 219) -* __dpd_floatunsditd: Decimal float library routines. - (line 223) -* __dpd_floatunssidd: Decimal float library routines. - (line 212) -* __dpd_floatunssisd: Decimal float library routines. - (line 210) -* __dpd_floatunssitd: Decimal float library routines. - (line 214) -* __dpd_gedd2: Decimal float library routines. - (line 275) -* __dpd_gesd2: Decimal float library routines. - (line 273) -* __dpd_getd2: Decimal float library routines. - (line 277) -* __dpd_gtdd2: Decimal float library routines. - (line 302) -* __dpd_gtsd2: Decimal float library routines. - (line 300) -* __dpd_gttd2: Decimal float library routines. - (line 304) -* __dpd_ledd2: Decimal float library routines. - (line 293) -* __dpd_lesd2: Decimal float library routines. - (line 291) -* __dpd_letd2: Decimal float library routines. - (line 295) -* __dpd_ltdd2: Decimal float library routines. - (line 284) -* __dpd_ltsd2: Decimal float library routines. - (line 282) -* __dpd_lttd2: Decimal float library routines. - (line 286) -* __dpd_muldd3: Decimal float library routines. - (line 50) -* __dpd_mulsd3: Decimal float library routines. - (line 46) -* __dpd_multd3: Decimal float library routines. - (line 54) -* __dpd_nedd2: Decimal float library routines. - (line 266) -* __dpd_negdd2: Decimal float library routines. - (line 76) -* __dpd_negsd2: Decimal float library routines. - (line 74) -* __dpd_negtd2: Decimal float library routines. - (line 78) -* __dpd_nesd2: Decimal float library routines. - (line 264) -* __dpd_netd2: Decimal float library routines. - (line 268) -* __dpd_subdd3: Decimal float library routines. - (line 35) -* __dpd_subsd3: Decimal float library routines. - (line 31) -* __dpd_subtd3: Decimal float library routines. - (line 39) -* __dpd_truncdddf: Decimal float library routines. - (line 151) -* __dpd_truncddsd2: Decimal float library routines. - (line 92) -* __dpd_truncddsf: Decimal float library routines. - (line 122) -* __dpd_truncdfsd: Decimal float library routines. - (line 109) -* __dpd_truncsdsf: Decimal float library routines. - (line 149) -* __dpd_trunctddd2: Decimal float library routines. - (line 96) -* __dpd_trunctddf: Decimal float library routines. - (line 128) -* __dpd_trunctdsd2: Decimal float library routines. - (line 94) -* __dpd_trunctdsf: Decimal float library routines. - (line 124) -* __dpd_trunctdtf: Decimal float library routines. - (line 153) -* __dpd_trunctdxf: Decimal float library routines. - (line 134) -* __dpd_trunctfdd: Decimal float library routines. - (line 117) -* __dpd_trunctfsd: Decimal float library routines. - (line 113) -* __dpd_truncxfdd: Decimal float library routines. - (line 115) -* __dpd_truncxfsd: Decimal float library routines. - (line 111) -* __dpd_unorddd2: Decimal float library routines. - (line 233) -* __dpd_unordsd2: Decimal float library routines. - (line 231) -* __dpd_unordtd2: Decimal float library routines. - (line 235) -* __DTOR_LIST__: Initialization. (line 25) -* __eqdf2: Soft float library routines. - (line 193) -* __eqsf2: Soft float library routines. - (line 192) -* __eqtf2: Soft float library routines. - (line 194) -* __extenddftf2: Soft float library routines. - (line 67) -* __extenddfxf2: Soft float library routines. - (line 68) -* __extendsfdf2: Soft float library routines. - (line 64) -* __extendsftf2: Soft float library routines. - (line 65) -* __extendsfxf2: Soft float library routines. - (line 66) -* __ffsdi2: Integer library routines. - (line 143) -* __ffsti2: Integer library routines. - (line 144) -* __fixdfdi: Soft float library routines. - (line 87) -* __fixdfsi: Soft float library routines. - (line 80) -* __fixdfti: Soft float library routines. - (line 93) -* __fixsfdi: Soft float library routines. - (line 86) -* __fixsfsi: Soft float library routines. - (line 79) -* __fixsfti: Soft float library routines. - (line 92) -* __fixtfdi: Soft float library routines. - (line 88) -* __fixtfsi: Soft float library routines. - (line 81) -* __fixtfti: Soft float library routines. - (line 94) -* __fixunsdfdi: Soft float library routines. - (line 107) -* __fixunsdfsi: Soft float library routines. - (line 100) -* __fixunsdfti: Soft float library routines. - (line 114) -* __fixunssfdi: Soft float library routines. - (line 106) -* __fixunssfsi: Soft float library routines. - (line 99) -* __fixunssfti: Soft float library routines. - (line 113) -* __fixunstfdi: Soft float library routines. - (line 108) -* __fixunstfsi: Soft float library routines. - (line 101) -* __fixunstfti: Soft float library routines. - (line 115) -* __fixunsxfdi: Soft float library routines. - (line 109) -* __fixunsxfsi: Soft float library routines. - (line 102) -* __fixunsxfti: Soft float library routines. - (line 116) -* __fixxfdi: Soft float library routines. - (line 89) -* __fixxfsi: Soft float library routines. - (line 82) -* __fixxfti: Soft float library routines. - (line 95) -* __floatdidf: Soft float library routines. - (line 127) -* __floatdisf: Soft float library routines. - (line 126) -* __floatditf: Soft float library routines. - (line 128) -* __floatdixf: Soft float library routines. - (line 129) -* __floatsidf: Soft float library routines. - (line 121) -* __floatsisf: Soft float library routines. - (line 120) -* __floatsitf: Soft float library routines. - (line 122) -* __floatsixf: Soft float library routines. - (line 123) -* __floattidf: Soft float library routines. - (line 133) -* __floattisf: Soft float library routines. - (line 132) -* __floattitf: Soft float library routines. - (line 134) -* __floattixf: Soft float library routines. - (line 135) -* __floatundidf: Soft float library routines. - (line 145) -* __floatundisf: Soft float library routines. - (line 144) -* __floatunditf: Soft float library routines. - (line 146) -* __floatundixf: Soft float library routines. - (line 147) -* __floatunsidf: Soft float library routines. - (line 139) -* __floatunsisf: Soft float library routines. - (line 138) -* __floatunsitf: Soft float library routines. - (line 140) -* __floatunsixf: Soft float library routines. - (line 141) -* __floatuntidf: Soft float library routines. - (line 151) -* __floatuntisf: Soft float library routines. - (line 150) -* __floatuntitf: Soft float library routines. - (line 152) -* __floatuntixf: Soft float library routines. - (line 153) -* __fractdadf: Fixed-point fractional library routines. - (line 635) -* __fractdadi: Fixed-point fractional library routines. - (line 632) -* __fractdadq: Fixed-point fractional library routines. - (line 615) -* __fractdaha2: Fixed-point fractional library routines. - (line 616) -* __fractdahi: Fixed-point fractional library routines. - (line 630) -* __fractdahq: Fixed-point fractional library routines. - (line 613) -* __fractdaqi: Fixed-point fractional library routines. - (line 629) -* __fractdaqq: Fixed-point fractional library routines. - (line 612) -* __fractdasa2: Fixed-point fractional library routines. - (line 617) -* __fractdasf: Fixed-point fractional library routines. - (line 634) -* __fractdasi: Fixed-point fractional library routines. - (line 631) -* __fractdasq: Fixed-point fractional library routines. - (line 614) -* __fractdata2: Fixed-point fractional library routines. - (line 618) -* __fractdati: Fixed-point fractional library routines. - (line 633) -* __fractdauda: Fixed-point fractional library routines. - (line 626) -* __fractdaudq: Fixed-point fractional library routines. - (line 622) -* __fractdauha: Fixed-point fractional library routines. - (line 624) -* __fractdauhq: Fixed-point fractional library routines. - (line 620) -* __fractdauqq: Fixed-point fractional library routines. - (line 619) -* __fractdausa: Fixed-point fractional library routines. - (line 625) -* __fractdausq: Fixed-point fractional library routines. - (line 621) -* __fractdauta: Fixed-point fractional library routines. - (line 627) -* __fractdfda: Fixed-point fractional library routines. - (line 1024) -* __fractdfdq: Fixed-point fractional library routines. - (line 1021) -* __fractdfha: Fixed-point fractional library routines. - (line 1022) -* __fractdfhq: Fixed-point fractional library routines. - (line 1019) -* __fractdfqq: Fixed-point fractional library routines. - (line 1018) -* __fractdfsa: Fixed-point fractional library routines. - (line 1023) -* __fractdfsq: Fixed-point fractional library routines. - (line 1020) -* __fractdfta: Fixed-point fractional library routines. - (line 1025) -* __fractdfuda: Fixed-point fractional library routines. - (line 1032) -* __fractdfudq: Fixed-point fractional library routines. - (line 1029) -* __fractdfuha: Fixed-point fractional library routines. - (line 1030) -* __fractdfuhq: Fixed-point fractional library routines. - (line 1027) -* __fractdfuqq: Fixed-point fractional library routines. - (line 1026) -* __fractdfusa: Fixed-point fractional library routines. - (line 1031) -* __fractdfusq: Fixed-point fractional library routines. - (line 1028) -* __fractdfuta: Fixed-point fractional library routines. - (line 1033) -* __fractdida: Fixed-point fractional library routines. - (line 974) -* __fractdidq: Fixed-point fractional library routines. - (line 971) -* __fractdiha: Fixed-point fractional library routines. - (line 972) -* __fractdihq: Fixed-point fractional library routines. - (line 969) -* __fractdiqq: Fixed-point fractional library routines. - (line 968) -* __fractdisa: Fixed-point fractional library routines. - (line 973) -* __fractdisq: Fixed-point fractional library routines. - (line 970) -* __fractdita: Fixed-point fractional library routines. - (line 975) -* __fractdiuda: Fixed-point fractional library routines. - (line 982) -* __fractdiudq: Fixed-point fractional library routines. - (line 979) -* __fractdiuha: Fixed-point fractional library routines. - (line 980) -* __fractdiuhq: Fixed-point fractional library routines. - (line 977) -* __fractdiuqq: Fixed-point fractional library routines. - (line 976) -* __fractdiusa: Fixed-point fractional library routines. - (line 981) -* __fractdiusq: Fixed-point fractional library routines. - (line 978) -* __fractdiuta: Fixed-point fractional library routines. - (line 983) -* __fractdqda: Fixed-point fractional library routines. - (line 543) -* __fractdqdf: Fixed-point fractional library routines. - (line 565) -* __fractdqdi: Fixed-point fractional library routines. - (line 562) -* __fractdqha: Fixed-point fractional library routines. - (line 541) -* __fractdqhi: Fixed-point fractional library routines. - (line 560) -* __fractdqhq2: Fixed-point fractional library routines. - (line 539) -* __fractdqqi: Fixed-point fractional library routines. - (line 559) -* __fractdqqq2: Fixed-point fractional library routines. - (line 538) -* __fractdqsa: Fixed-point fractional library routines. - (line 542) -* __fractdqsf: Fixed-point fractional library routines. - (line 564) -* __fractdqsi: Fixed-point fractional library routines. - (line 561) -* __fractdqsq2: Fixed-point fractional library routines. - (line 540) -* __fractdqta: Fixed-point fractional library routines. - (line 544) -* __fractdqti: Fixed-point fractional library routines. - (line 563) -* __fractdquda: Fixed-point fractional library routines. - (line 555) -* __fractdqudq: Fixed-point fractional library routines. - (line 550) -* __fractdquha: Fixed-point fractional library routines. - (line 552) -* __fractdquhq: Fixed-point fractional library routines. - (line 547) -* __fractdquqq: Fixed-point fractional library routines. - (line 545) -* __fractdqusa: Fixed-point fractional library routines. - (line 554) -* __fractdqusq: Fixed-point fractional library routines. - (line 548) -* __fractdquta: Fixed-point fractional library routines. - (line 557) -* __fracthada2: Fixed-point fractional library routines. - (line 571) -* __fracthadf: Fixed-point fractional library routines. - (line 589) -* __fracthadi: Fixed-point fractional library routines. - (line 586) -* __fracthadq: Fixed-point fractional library routines. - (line 569) -* __fracthahi: Fixed-point fractional library routines. - (line 584) -* __fracthahq: Fixed-point fractional library routines. - (line 567) -* __fracthaqi: Fixed-point fractional library routines. - (line 583) -* __fracthaqq: Fixed-point fractional library routines. - (line 566) -* __fracthasa2: Fixed-point fractional library routines. - (line 570) -* __fracthasf: Fixed-point fractional library routines. - (line 588) -* __fracthasi: Fixed-point fractional library routines. - (line 585) -* __fracthasq: Fixed-point fractional library routines. - (line 568) -* __fracthata2: Fixed-point fractional library routines. - (line 572) -* __fracthati: Fixed-point fractional library routines. - (line 587) -* __fracthauda: Fixed-point fractional library routines. - (line 580) -* __fracthaudq: Fixed-point fractional library routines. - (line 576) -* __fracthauha: Fixed-point fractional library routines. - (line 578) -* __fracthauhq: Fixed-point fractional library routines. - (line 574) -* __fracthauqq: Fixed-point fractional library routines. - (line 573) -* __fracthausa: Fixed-point fractional library routines. - (line 579) -* __fracthausq: Fixed-point fractional library routines. - (line 575) -* __fracthauta: Fixed-point fractional library routines. - (line 581) -* __fracthida: Fixed-point fractional library routines. - (line 942) -* __fracthidq: Fixed-point fractional library routines. - (line 939) -* __fracthiha: Fixed-point fractional library routines. - (line 940) -* __fracthihq: Fixed-point fractional library routines. - (line 937) -* __fracthiqq: Fixed-point fractional library routines. - (line 936) -* __fracthisa: Fixed-point fractional library routines. - (line 941) -* __fracthisq: Fixed-point fractional library routines. - (line 938) -* __fracthita: Fixed-point fractional library routines. - (line 943) -* __fracthiuda: Fixed-point fractional library routines. - (line 950) -* __fracthiudq: Fixed-point fractional library routines. - (line 947) -* __fracthiuha: Fixed-point fractional library routines. - (line 948) -* __fracthiuhq: Fixed-point fractional library routines. - (line 945) -* __fracthiuqq: Fixed-point fractional library routines. - (line 944) -* __fracthiusa: Fixed-point fractional library routines. - (line 949) -* __fracthiusq: Fixed-point fractional library routines. - (line 946) -* __fracthiuta: Fixed-point fractional library routines. - (line 951) -* __fracthqda: Fixed-point fractional library routines. - (line 497) -* __fracthqdf: Fixed-point fractional library routines. - (line 513) -* __fracthqdi: Fixed-point fractional library routines. - (line 510) -* __fracthqdq2: Fixed-point fractional library routines. - (line 494) -* __fracthqha: Fixed-point fractional library routines. - (line 495) -* __fracthqhi: Fixed-point fractional library routines. - (line 508) -* __fracthqqi: Fixed-point fractional library routines. - (line 507) -* __fracthqqq2: Fixed-point fractional library routines. - (line 492) -* __fracthqsa: Fixed-point fractional library routines. - (line 496) -* __fracthqsf: Fixed-point fractional library routines. - (line 512) -* __fracthqsi: Fixed-point fractional library routines. - (line 509) -* __fracthqsq2: Fixed-point fractional library routines. - (line 493) -* __fracthqta: Fixed-point fractional library routines. - (line 498) -* __fracthqti: Fixed-point fractional library routines. - (line 511) -* __fracthquda: Fixed-point fractional library routines. - (line 505) -* __fracthqudq: Fixed-point fractional library routines. - (line 502) -* __fracthquha: Fixed-point fractional library routines. - (line 503) -* __fracthquhq: Fixed-point fractional library routines. - (line 500) -* __fracthquqq: Fixed-point fractional library routines. - (line 499) -* __fracthqusa: Fixed-point fractional library routines. - (line 504) -* __fracthqusq: Fixed-point fractional library routines. - (line 501) -* __fracthquta: Fixed-point fractional library routines. - (line 506) -* __fractqida: Fixed-point fractional library routines. - (line 924) -* __fractqidq: Fixed-point fractional library routines. - (line 921) -* __fractqiha: Fixed-point fractional library routines. - (line 922) -* __fractqihq: Fixed-point fractional library routines. - (line 919) -* __fractqiqq: Fixed-point fractional library routines. - (line 918) -* __fractqisa: Fixed-point fractional library routines. - (line 923) -* __fractqisq: Fixed-point fractional library routines. - (line 920) -* __fractqita: Fixed-point fractional library routines. - (line 925) -* __fractqiuda: Fixed-point fractional library routines. - (line 933) -* __fractqiudq: Fixed-point fractional library routines. - (line 929) -* __fractqiuha: Fixed-point fractional library routines. - (line 931) -* __fractqiuhq: Fixed-point fractional library routines. - (line 927) -* __fractqiuqq: Fixed-point fractional library routines. - (line 926) -* __fractqiusa: Fixed-point fractional library routines. - (line 932) -* __fractqiusq: Fixed-point fractional library routines. - (line 928) -* __fractqiuta: Fixed-point fractional library routines. - (line 934) -* __fractqqda: Fixed-point fractional library routines. - (line 473) -* __fractqqdf: Fixed-point fractional library routines. - (line 491) -* __fractqqdi: Fixed-point fractional library routines. - (line 488) -* __fractqqdq2: Fixed-point fractional library routines. - (line 470) -* __fractqqha: Fixed-point fractional library routines. - (line 471) -* __fractqqhi: Fixed-point fractional library routines. - (line 486) -* __fractqqhq2: Fixed-point fractional library routines. - (line 468) -* __fractqqqi: Fixed-point fractional library routines. - (line 485) -* __fractqqsa: Fixed-point fractional library routines. - (line 472) -* __fractqqsf: Fixed-point fractional library routines. - (line 490) -* __fractqqsi: Fixed-point fractional library routines. - (line 487) -* __fractqqsq2: Fixed-point fractional library routines. - (line 469) -* __fractqqta: Fixed-point fractional library routines. - (line 474) -* __fractqqti: Fixed-point fractional library routines. - (line 489) -* __fractqquda: Fixed-point fractional library routines. - (line 482) -* __fractqqudq: Fixed-point fractional library routines. - (line 478) -* __fractqquha: Fixed-point fractional library routines. - (line 480) -* __fractqquhq: Fixed-point fractional library routines. - (line 476) -* __fractqquqq: Fixed-point fractional library routines. - (line 475) -* __fractqqusa: Fixed-point fractional library routines. - (line 481) -* __fractqqusq: Fixed-point fractional library routines. - (line 477) -* __fractqquta: Fixed-point fractional library routines. - (line 483) -* __fractsada2: Fixed-point fractional library routines. - (line 595) -* __fractsadf: Fixed-point fractional library routines. - (line 611) -* __fractsadi: Fixed-point fractional library routines. - (line 608) -* __fractsadq: Fixed-point fractional library routines. - (line 593) -* __fractsaha2: Fixed-point fractional library routines. - (line 594) -* __fractsahi: Fixed-point fractional library routines. - (line 606) -* __fractsahq: Fixed-point fractional library routines. - (line 591) -* __fractsaqi: Fixed-point fractional library routines. - (line 605) -* __fractsaqq: Fixed-point fractional library routines. - (line 590) -* __fractsasf: Fixed-point fractional library routines. - (line 610) -* __fractsasi: Fixed-point fractional library routines. - (line 607) -* __fractsasq: Fixed-point fractional library routines. - (line 592) -* __fractsata2: Fixed-point fractional library routines. - (line 596) -* __fractsati: Fixed-point fractional library routines. - (line 609) -* __fractsauda: Fixed-point fractional library routines. - (line 603) -* __fractsaudq: Fixed-point fractional library routines. - (line 600) -* __fractsauha: Fixed-point fractional library routines. - (line 601) -* __fractsauhq: Fixed-point fractional library routines. - (line 598) -* __fractsauqq: Fixed-point fractional library routines. - (line 597) -* __fractsausa: Fixed-point fractional library routines. - (line 602) -* __fractsausq: Fixed-point fractional library routines. - (line 599) -* __fractsauta: Fixed-point fractional library routines. - (line 604) -* __fractsfda: Fixed-point fractional library routines. - (line 1008) -* __fractsfdq: Fixed-point fractional library routines. - (line 1005) -* __fractsfha: Fixed-point fractional library routines. - (line 1006) -* __fractsfhq: Fixed-point fractional library routines. - (line 1003) -* __fractsfqq: Fixed-point fractional library routines. - (line 1002) -* __fractsfsa: Fixed-point fractional library routines. - (line 1007) -* __fractsfsq: Fixed-point fractional library routines. - (line 1004) -* __fractsfta: Fixed-point fractional library routines. - (line 1009) -* __fractsfuda: Fixed-point fractional library routines. - (line 1016) -* __fractsfudq: Fixed-point fractional library routines. - (line 1013) -* __fractsfuha: Fixed-point fractional library routines. - (line 1014) -* __fractsfuhq: Fixed-point fractional library routines. - (line 1011) -* __fractsfuqq: Fixed-point fractional library routines. - (line 1010) -* __fractsfusa: Fixed-point fractional library routines. - (line 1015) -* __fractsfusq: Fixed-point fractional library routines. - (line 1012) -* __fractsfuta: Fixed-point fractional library routines. - (line 1017) -* __fractsida: Fixed-point fractional library routines. - (line 958) -* __fractsidq: Fixed-point fractional library routines. - (line 955) -* __fractsiha: Fixed-point fractional library routines. - (line 956) -* __fractsihq: Fixed-point fractional library routines. - (line 953) -* __fractsiqq: Fixed-point fractional library routines. - (line 952) -* __fractsisa: Fixed-point fractional library routines. - (line 957) -* __fractsisq: Fixed-point fractional library routines. - (line 954) -* __fractsita: Fixed-point fractional library routines. - (line 959) -* __fractsiuda: Fixed-point fractional library routines. - (line 966) -* __fractsiudq: Fixed-point fractional library routines. - (line 963) -* __fractsiuha: Fixed-point fractional library routines. - (line 964) -* __fractsiuhq: Fixed-point fractional library routines. - (line 961) -* __fractsiuqq: Fixed-point fractional library routines. - (line 960) -* __fractsiusa: Fixed-point fractional library routines. - (line 965) -* __fractsiusq: Fixed-point fractional library routines. - (line 962) -* __fractsiuta: Fixed-point fractional library routines. - (line 967) -* __fractsqda: Fixed-point fractional library routines. - (line 519) -* __fractsqdf: Fixed-point fractional library routines. - (line 537) -* __fractsqdi: Fixed-point fractional library routines. - (line 534) -* __fractsqdq2: Fixed-point fractional library routines. - (line 516) -* __fractsqha: Fixed-point fractional library routines. - (line 517) -* __fractsqhi: Fixed-point fractional library routines. - (line 532) -* __fractsqhq2: Fixed-point fractional library routines. - (line 515) -* __fractsqqi: Fixed-point fractional library routines. - (line 531) -* __fractsqqq2: Fixed-point fractional library routines. - (line 514) -* __fractsqsa: Fixed-point fractional library routines. - (line 518) -* __fractsqsf: Fixed-point fractional library routines. - (line 536) -* __fractsqsi: Fixed-point fractional library routines. - (line 533) -* __fractsqta: Fixed-point fractional library routines. - (line 520) -* __fractsqti: Fixed-point fractional library routines. - (line 535) -* __fractsquda: Fixed-point fractional library routines. - (line 528) -* __fractsqudq: Fixed-point fractional library routines. - (line 524) -* __fractsquha: Fixed-point fractional library routines. - (line 526) -* __fractsquhq: Fixed-point fractional library routines. - (line 522) -* __fractsquqq: Fixed-point fractional library routines. - (line 521) -* __fractsqusa: Fixed-point fractional library routines. - (line 527) -* __fractsqusq: Fixed-point fractional library routines. - (line 523) -* __fractsquta: Fixed-point fractional library routines. - (line 529) -* __fracttada2: Fixed-point fractional library routines. - (line 642) -* __fracttadf: Fixed-point fractional library routines. - (line 663) -* __fracttadi: Fixed-point fractional library routines. - (line 660) -* __fracttadq: Fixed-point fractional library routines. - (line 639) -* __fracttaha2: Fixed-point fractional library routines. - (line 640) -* __fracttahi: Fixed-point fractional library routines. - (line 658) -* __fracttahq: Fixed-point fractional library routines. - (line 637) -* __fracttaqi: Fixed-point fractional library routines. - (line 657) -* __fracttaqq: Fixed-point fractional library routines. - (line 636) -* __fracttasa2: Fixed-point fractional library routines. - (line 641) -* __fracttasf: Fixed-point fractional library routines. - (line 662) -* __fracttasi: Fixed-point fractional library routines. - (line 659) -* __fracttasq: Fixed-point fractional library routines. - (line 638) -* __fracttati: Fixed-point fractional library routines. - (line 661) -* __fracttauda: Fixed-point fractional library routines. - (line 653) -* __fracttaudq: Fixed-point fractional library routines. - (line 648) -* __fracttauha: Fixed-point fractional library routines. - (line 650) -* __fracttauhq: Fixed-point fractional library routines. - (line 645) -* __fracttauqq: Fixed-point fractional library routines. - (line 643) -* __fracttausa: Fixed-point fractional library routines. - (line 652) -* __fracttausq: Fixed-point fractional library routines. - (line 646) -* __fracttauta: Fixed-point fractional library routines. - (line 655) -* __fracttida: Fixed-point fractional library routines. - (line 990) -* __fracttidq: Fixed-point fractional library routines. - (line 987) -* __fracttiha: Fixed-point fractional library routines. - (line 988) -* __fracttihq: Fixed-point fractional library routines. - (line 985) -* __fracttiqq: Fixed-point fractional library routines. - (line 984) -* __fracttisa: Fixed-point fractional library routines. - (line 989) -* __fracttisq: Fixed-point fractional library routines. - (line 986) -* __fracttita: Fixed-point fractional library routines. - (line 991) -* __fracttiuda: Fixed-point fractional library routines. - (line 999) -* __fracttiudq: Fixed-point fractional library routines. - (line 995) -* __fracttiuha: Fixed-point fractional library routines. - (line 997) -* __fracttiuhq: Fixed-point fractional library routines. - (line 993) -* __fracttiuqq: Fixed-point fractional library routines. - (line 992) -* __fracttiusa: Fixed-point fractional library routines. - (line 998) -* __fracttiusq: Fixed-point fractional library routines. - (line 994) -* __fracttiuta: Fixed-point fractional library routines. - (line 1000) -* __fractudada: Fixed-point fractional library routines. - (line 857) -* __fractudadf: Fixed-point fractional library routines. - (line 880) -* __fractudadi: Fixed-point fractional library routines. - (line 877) -* __fractudadq: Fixed-point fractional library routines. - (line 853) -* __fractudaha: Fixed-point fractional library routines. - (line 855) -* __fractudahi: Fixed-point fractional library routines. - (line 875) -* __fractudahq: Fixed-point fractional library routines. - (line 851) -* __fractudaqi: Fixed-point fractional library routines. - (line 874) -* __fractudaqq: Fixed-point fractional library routines. - (line 850) -* __fractudasa: Fixed-point fractional library routines. - (line 856) -* __fractudasf: Fixed-point fractional library routines. - (line 879) -* __fractudasi: Fixed-point fractional library routines. - (line 876) -* __fractudasq: Fixed-point fractional library routines. - (line 852) -* __fractudata: Fixed-point fractional library routines. - (line 858) -* __fractudati: Fixed-point fractional library routines. - (line 878) -* __fractudaudq: Fixed-point fractional library routines. - (line 866) -* __fractudauha2: Fixed-point fractional library routines. - (line 868) -* __fractudauhq: Fixed-point fractional library routines. - (line 862) -* __fractudauqq: Fixed-point fractional library routines. - (line 860) -* __fractudausa2: Fixed-point fractional library routines. - (line 870) -* __fractudausq: Fixed-point fractional library routines. - (line 864) -* __fractudauta2: Fixed-point fractional library routines. - (line 872) -* __fractudqda: Fixed-point fractional library routines. - (line 764) -* __fractudqdf: Fixed-point fractional library routines. - (line 790) -* __fractudqdi: Fixed-point fractional library routines. - (line 786) -* __fractudqdq: Fixed-point fractional library routines. - (line 759) -* __fractudqha: Fixed-point fractional library routines. - (line 761) -* __fractudqhi: Fixed-point fractional library routines. - (line 784) -* __fractudqhq: Fixed-point fractional library routines. - (line 756) -* __fractudqqi: Fixed-point fractional library routines. - (line 782) -* __fractudqqq: Fixed-point fractional library routines. - (line 754) -* __fractudqsa: Fixed-point fractional library routines. - (line 763) -* __fractudqsf: Fixed-point fractional library routines. - (line 789) -* __fractudqsi: Fixed-point fractional library routines. - (line 785) -* __fractudqsq: Fixed-point fractional library routines. - (line 757) -* __fractudqta: Fixed-point fractional library routines. - (line 766) -* __fractudqti: Fixed-point fractional library routines. - (line 787) -* __fractudquda: Fixed-point fractional library routines. - (line 778) -* __fractudquha: Fixed-point fractional library routines. - (line 774) -* __fractudquhq2: Fixed-point fractional library routines. - (line 770) -* __fractudquqq2: Fixed-point fractional library routines. - (line 768) -* __fractudqusa: Fixed-point fractional library routines. - (line 776) -* __fractudqusq2: Fixed-point fractional library routines. - (line 772) -* __fractudquta: Fixed-point fractional library routines. - (line 780) -* __fractuhada: Fixed-point fractional library routines. - (line 798) -* __fractuhadf: Fixed-point fractional library routines. - (line 821) -* __fractuhadi: Fixed-point fractional library routines. - (line 818) -* __fractuhadq: Fixed-point fractional library routines. - (line 794) -* __fractuhaha: Fixed-point fractional library routines. - (line 796) -* __fractuhahi: Fixed-point fractional library routines. - (line 816) -* __fractuhahq: Fixed-point fractional library routines. - (line 792) -* __fractuhaqi: Fixed-point fractional library routines. - (line 815) -* __fractuhaqq: Fixed-point fractional library routines. - (line 791) -* __fractuhasa: Fixed-point fractional library routines. - (line 797) -* __fractuhasf: Fixed-point fractional library routines. - (line 820) -* __fractuhasi: Fixed-point fractional library routines. - (line 817) -* __fractuhasq: Fixed-point fractional library routines. - (line 793) -* __fractuhata: Fixed-point fractional library routines. - (line 799) -* __fractuhati: Fixed-point fractional library routines. - (line 819) -* __fractuhauda2: Fixed-point fractional library routines. - (line 811) -* __fractuhaudq: Fixed-point fractional library routines. - (line 807) -* __fractuhauhq: Fixed-point fractional library routines. - (line 803) -* __fractuhauqq: Fixed-point fractional library routines. - (line 801) -* __fractuhausa2: Fixed-point fractional library routines. - (line 809) -* __fractuhausq: Fixed-point fractional library routines. - (line 805) -* __fractuhauta2: Fixed-point fractional library routines. - (line 813) -* __fractuhqda: Fixed-point fractional library routines. - (line 701) -* __fractuhqdf: Fixed-point fractional library routines. - (line 722) -* __fractuhqdi: Fixed-point fractional library routines. - (line 719) -* __fractuhqdq: Fixed-point fractional library routines. - (line 698) -* __fractuhqha: Fixed-point fractional library routines. - (line 699) -* __fractuhqhi: Fixed-point fractional library routines. - (line 717) -* __fractuhqhq: Fixed-point fractional library routines. - (line 696) -* __fractuhqqi: Fixed-point fractional library routines. - (line 716) -* __fractuhqqq: Fixed-point fractional library routines. - (line 695) -* __fractuhqsa: Fixed-point fractional library routines. - (line 700) -* __fractuhqsf: Fixed-point fractional library routines. - (line 721) -* __fractuhqsi: Fixed-point fractional library routines. - (line 718) -* __fractuhqsq: Fixed-point fractional library routines. - (line 697) -* __fractuhqta: Fixed-point fractional library routines. - (line 702) -* __fractuhqti: Fixed-point fractional library routines. - (line 720) -* __fractuhquda: Fixed-point fractional library routines. - (line 712) -* __fractuhqudq2: Fixed-point fractional library routines. - (line 707) -* __fractuhquha: Fixed-point fractional library routines. - (line 709) -* __fractuhquqq2: Fixed-point fractional library routines. - (line 703) -* __fractuhqusa: Fixed-point fractional library routines. - (line 711) -* __fractuhqusq2: Fixed-point fractional library routines. - (line 705) -* __fractuhquta: Fixed-point fractional library routines. - (line 714) -* __fractunsdadi: Fixed-point fractional library routines. - (line 1554) -* __fractunsdahi: Fixed-point fractional library routines. - (line 1552) -* __fractunsdaqi: Fixed-point fractional library routines. - (line 1551) -* __fractunsdasi: Fixed-point fractional library routines. - (line 1553) -* __fractunsdati: Fixed-point fractional library routines. - (line 1555) -* __fractunsdida: Fixed-point fractional library routines. - (line 1706) -* __fractunsdidq: Fixed-point fractional library routines. - (line 1703) -* __fractunsdiha: Fixed-point fractional library routines. - (line 1704) -* __fractunsdihq: Fixed-point fractional library routines. - (line 1701) -* __fractunsdiqq: Fixed-point fractional library routines. - (line 1700) -* __fractunsdisa: Fixed-point fractional library routines. - (line 1705) -* __fractunsdisq: Fixed-point fractional library routines. - (line 1702) -* __fractunsdita: Fixed-point fractional library routines. - (line 1707) -* __fractunsdiuda: Fixed-point fractional library routines. - (line 1718) -* __fractunsdiudq: Fixed-point fractional library routines. - (line 1713) -* __fractunsdiuha: Fixed-point fractional library routines. - (line 1715) -* __fractunsdiuhq: Fixed-point fractional library routines. - (line 1710) -* __fractunsdiuqq: Fixed-point fractional library routines. - (line 1708) -* __fractunsdiusa: Fixed-point fractional library routines. - (line 1717) -* __fractunsdiusq: Fixed-point fractional library routines. - (line 1711) -* __fractunsdiuta: Fixed-point fractional library routines. - (line 1720) -* __fractunsdqdi: Fixed-point fractional library routines. - (line 1538) -* __fractunsdqhi: Fixed-point fractional library routines. - (line 1536) -* __fractunsdqqi: Fixed-point fractional library routines. - (line 1535) -* __fractunsdqsi: Fixed-point fractional library routines. - (line 1537) -* __fractunsdqti: Fixed-point fractional library routines. - (line 1539) -* __fractunshadi: Fixed-point fractional library routines. - (line 1544) -* __fractunshahi: Fixed-point fractional library routines. - (line 1542) -* __fractunshaqi: Fixed-point fractional library routines. - (line 1541) -* __fractunshasi: Fixed-point fractional library routines. - (line 1543) -* __fractunshati: Fixed-point fractional library routines. - (line 1545) -* __fractunshida: Fixed-point fractional library routines. - (line 1662) -* __fractunshidq: Fixed-point fractional library routines. - (line 1659) -* __fractunshiha: Fixed-point fractional library routines. - (line 1660) -* __fractunshihq: Fixed-point fractional library routines. - (line 1657) -* __fractunshiqq: Fixed-point fractional library routines. - (line 1656) -* __fractunshisa: Fixed-point fractional library routines. - (line 1661) -* __fractunshisq: Fixed-point fractional library routines. - (line 1658) -* __fractunshita: Fixed-point fractional library routines. - (line 1663) -* __fractunshiuda: Fixed-point fractional library routines. - (line 1674) -* __fractunshiudq: Fixed-point fractional library routines. - (line 1669) -* __fractunshiuha: Fixed-point fractional library routines. - (line 1671) -* __fractunshiuhq: Fixed-point fractional library routines. - (line 1666) -* __fractunshiuqq: Fixed-point fractional library routines. - (line 1664) -* __fractunshiusa: Fixed-point fractional library routines. - (line 1673) -* __fractunshiusq: Fixed-point fractional library routines. - (line 1667) -* __fractunshiuta: Fixed-point fractional library routines. - (line 1676) -* __fractunshqdi: Fixed-point fractional library routines. - (line 1528) -* __fractunshqhi: Fixed-point fractional library routines. - (line 1526) -* __fractunshqqi: Fixed-point fractional library routines. - (line 1525) -* __fractunshqsi: Fixed-point fractional library routines. - (line 1527) -* __fractunshqti: Fixed-point fractional library routines. - (line 1529) -* __fractunsqida: Fixed-point fractional library routines. - (line 1640) -* __fractunsqidq: Fixed-point fractional library routines. - (line 1637) -* __fractunsqiha: Fixed-point fractional library routines. - (line 1638) -* __fractunsqihq: Fixed-point fractional library routines. - (line 1635) -* __fractunsqiqq: Fixed-point fractional library routines. - (line 1634) -* __fractunsqisa: Fixed-point fractional library routines. - (line 1639) -* __fractunsqisq: Fixed-point fractional library routines. - (line 1636) -* __fractunsqita: Fixed-point fractional library routines. - (line 1641) -* __fractunsqiuda: Fixed-point fractional library routines. - (line 1652) -* __fractunsqiudq: Fixed-point fractional library routines. - (line 1647) -* __fractunsqiuha: Fixed-point fractional library routines. - (line 1649) -* __fractunsqiuhq: Fixed-point fractional library routines. - (line 1644) -* __fractunsqiuqq: Fixed-point fractional library routines. - (line 1642) -* __fractunsqiusa: Fixed-point fractional library routines. - (line 1651) -* __fractunsqiusq: Fixed-point fractional library routines. - (line 1645) -* __fractunsqiuta: Fixed-point fractional library routines. - (line 1654) -* __fractunsqqdi: Fixed-point fractional library routines. - (line 1523) -* __fractunsqqhi: Fixed-point fractional library routines. - (line 1521) -* __fractunsqqqi: Fixed-point fractional library routines. - (line 1520) -* __fractunsqqsi: Fixed-point fractional library routines. - (line 1522) -* __fractunsqqti: Fixed-point fractional library routines. - (line 1524) -* __fractunssadi: Fixed-point fractional library routines. - (line 1549) -* __fractunssahi: Fixed-point fractional library routines. - (line 1547) -* __fractunssaqi: Fixed-point fractional library routines. - (line 1546) -* __fractunssasi: Fixed-point fractional library routines. - (line 1548) -* __fractunssati: Fixed-point fractional library routines. - (line 1550) -* __fractunssida: Fixed-point fractional library routines. - (line 1684) -* __fractunssidq: Fixed-point fractional library routines. - (line 1681) -* __fractunssiha: Fixed-point fractional library routines. - (line 1682) -* __fractunssihq: Fixed-point fractional library routines. - (line 1679) -* __fractunssiqq: Fixed-point fractional library routines. - (line 1678) -* __fractunssisa: Fixed-point fractional library routines. - (line 1683) -* __fractunssisq: Fixed-point fractional library routines. - (line 1680) -* __fractunssita: Fixed-point fractional library routines. - (line 1685) -* __fractunssiuda: Fixed-point fractional library routines. - (line 1696) -* __fractunssiudq: Fixed-point fractional library routines. - (line 1691) -* __fractunssiuha: Fixed-point fractional library routines. - (line 1693) -* __fractunssiuhq: Fixed-point fractional library routines. - (line 1688) -* __fractunssiuqq: Fixed-point fractional library routines. - (line 1686) -* __fractunssiusa: Fixed-point fractional library routines. - (line 1695) -* __fractunssiusq: Fixed-point fractional library routines. - (line 1689) -* __fractunssiuta: Fixed-point fractional library routines. - (line 1698) -* __fractunssqdi: Fixed-point fractional library routines. - (line 1533) -* __fractunssqhi: Fixed-point fractional library routines. - (line 1531) -* __fractunssqqi: Fixed-point fractional library routines. - (line 1530) -* __fractunssqsi: Fixed-point fractional library routines. - (line 1532) -* __fractunssqti: Fixed-point fractional library routines. - (line 1534) -* __fractunstadi: Fixed-point fractional library routines. - (line 1559) -* __fractunstahi: Fixed-point fractional library routines. - (line 1557) -* __fractunstaqi: Fixed-point fractional library routines. - (line 1556) -* __fractunstasi: Fixed-point fractional library routines. - (line 1558) -* __fractunstati: Fixed-point fractional library routines. - (line 1560) -* __fractunstida: Fixed-point fractional library routines. - (line 1729) -* __fractunstidq: Fixed-point fractional library routines. - (line 1725) -* __fractunstiha: Fixed-point fractional library routines. - (line 1727) -* __fractunstihq: Fixed-point fractional library routines. - (line 1723) -* __fractunstiqq: Fixed-point fractional library routines. - (line 1722) -* __fractunstisa: Fixed-point fractional library routines. - (line 1728) -* __fractunstisq: Fixed-point fractional library routines. - (line 1724) -* __fractunstita: Fixed-point fractional library routines. - (line 1730) -* __fractunstiuda: Fixed-point fractional library routines. - (line 1744) -* __fractunstiudq: Fixed-point fractional library routines. - (line 1738) -* __fractunstiuha: Fixed-point fractional library routines. - (line 1740) -* __fractunstiuhq: Fixed-point fractional library routines. - (line 1734) -* __fractunstiuqq: Fixed-point fractional library routines. - (line 1732) -* __fractunstiusa: Fixed-point fractional library routines. - (line 1742) -* __fractunstiusq: Fixed-point fractional library routines. - (line 1736) -* __fractunstiuta: Fixed-point fractional library routines. - (line 1746) -* __fractunsudadi: Fixed-point fractional library routines. - (line 1620) -* __fractunsudahi: Fixed-point fractional library routines. - (line 1616) -* __fractunsudaqi: Fixed-point fractional library routines. - (line 1614) -* __fractunsudasi: Fixed-point fractional library routines. - (line 1618) -* __fractunsudati: Fixed-point fractional library routines. - (line 1622) -* __fractunsudqdi: Fixed-point fractional library routines. - (line 1594) -* __fractunsudqhi: Fixed-point fractional library routines. - (line 1590) -* __fractunsudqqi: Fixed-point fractional library routines. - (line 1588) -* __fractunsudqsi: Fixed-point fractional library routines. - (line 1592) -* __fractunsudqti: Fixed-point fractional library routines. - (line 1596) -* __fractunsuhadi: Fixed-point fractional library routines. - (line 1604) -* __fractunsuhahi: Fixed-point fractional library routines. - (line 1600) -* __fractunsuhaqi: Fixed-point fractional library routines. - (line 1598) -* __fractunsuhasi: Fixed-point fractional library routines. - (line 1602) -* __fractunsuhati: Fixed-point fractional library routines. - (line 1606) -* __fractunsuhqdi: Fixed-point fractional library routines. - (line 1575) -* __fractunsuhqhi: Fixed-point fractional library routines. - (line 1573) -* __fractunsuhqqi: Fixed-point fractional library routines. - (line 1572) -* __fractunsuhqsi: Fixed-point fractional library routines. - (line 1574) -* __fractunsuhqti: Fixed-point fractional library routines. - (line 1576) -* __fractunsuqqdi: Fixed-point fractional library routines. - (line 1568) -* __fractunsuqqhi: Fixed-point fractional library routines. - (line 1564) -* __fractunsuqqqi: Fixed-point fractional library routines. - (line 1562) -* __fractunsuqqsi: Fixed-point fractional library routines. - (line 1566) -* __fractunsuqqti: Fixed-point fractional library routines. - (line 1570) -* __fractunsusadi: Fixed-point fractional library routines. - (line 1611) -* __fractunsusahi: Fixed-point fractional library routines. - (line 1609) -* __fractunsusaqi: Fixed-point fractional library routines. - (line 1608) -* __fractunsusasi: Fixed-point fractional library routines. - (line 1610) -* __fractunsusati: Fixed-point fractional library routines. - (line 1612) -* __fractunsusqdi: Fixed-point fractional library routines. - (line 1584) -* __fractunsusqhi: Fixed-point fractional library routines. - (line 1580) -* __fractunsusqqi: Fixed-point fractional library routines. - (line 1578) -* __fractunsusqsi: Fixed-point fractional library routines. - (line 1582) -* __fractunsusqti: Fixed-point fractional library routines. - (line 1586) -* __fractunsutadi: Fixed-point fractional library routines. - (line 1630) -* __fractunsutahi: Fixed-point fractional library routines. - (line 1626) -* __fractunsutaqi: Fixed-point fractional library routines. - (line 1624) -* __fractunsutasi: Fixed-point fractional library routines. - (line 1628) -* __fractunsutati: Fixed-point fractional library routines. - (line 1632) -* __fractuqqda: Fixed-point fractional library routines. - (line 671) -* __fractuqqdf: Fixed-point fractional library routines. - (line 694) -* __fractuqqdi: Fixed-point fractional library routines. - (line 691) -* __fractuqqdq: Fixed-point fractional library routines. - (line 667) -* __fractuqqha: Fixed-point fractional library routines. - (line 669) -* __fractuqqhi: Fixed-point fractional library routines. - (line 689) -* __fractuqqhq: Fixed-point fractional library routines. - (line 665) -* __fractuqqqi: Fixed-point fractional library routines. - (line 688) -* __fractuqqqq: Fixed-point fractional library routines. - (line 664) -* __fractuqqsa: Fixed-point fractional library routines. - (line 670) -* __fractuqqsf: Fixed-point fractional library routines. - (line 693) -* __fractuqqsi: Fixed-point fractional library routines. - (line 690) -* __fractuqqsq: Fixed-point fractional library routines. - (line 666) -* __fractuqqta: Fixed-point fractional library routines. - (line 672) -* __fractuqqti: Fixed-point fractional library routines. - (line 692) -* __fractuqquda: Fixed-point fractional library routines. - (line 684) -* __fractuqqudq2: Fixed-point fractional library routines. - (line 678) -* __fractuqquha: Fixed-point fractional library routines. - (line 680) -* __fractuqquhq2: Fixed-point fractional library routines. - (line 674) -* __fractuqqusa: Fixed-point fractional library routines. - (line 682) -* __fractuqqusq2: Fixed-point fractional library routines. - (line 676) -* __fractuqquta: Fixed-point fractional library routines. - (line 686) -* __fractusada: Fixed-point fractional library routines. - (line 828) -* __fractusadf: Fixed-point fractional library routines. - (line 849) -* __fractusadi: Fixed-point fractional library routines. - (line 846) -* __fractusadq: Fixed-point fractional library routines. - (line 825) -* __fractusaha: Fixed-point fractional library routines. - (line 826) -* __fractusahi: Fixed-point fractional library routines. - (line 844) -* __fractusahq: Fixed-point fractional library routines. - (line 823) -* __fractusaqi: Fixed-point fractional library routines. - (line 843) -* __fractusaqq: Fixed-point fractional library routines. - (line 822) -* __fractusasa: Fixed-point fractional library routines. - (line 827) -* __fractusasf: Fixed-point fractional library routines. - (line 848) -* __fractusasi: Fixed-point fractional library routines. - (line 845) -* __fractusasq: Fixed-point fractional library routines. - (line 824) -* __fractusata: Fixed-point fractional library routines. - (line 829) -* __fractusati: Fixed-point fractional library routines. - (line 847) -* __fractusauda2: Fixed-point fractional library routines. - (line 839) -* __fractusaudq: Fixed-point fractional library routines. - (line 835) -* __fractusauha2: Fixed-point fractional library routines. - (line 837) -* __fractusauhq: Fixed-point fractional library routines. - (line 832) -* __fractusauqq: Fixed-point fractional library routines. - (line 830) -* __fractusausq: Fixed-point fractional library routines. - (line 833) -* __fractusauta2: Fixed-point fractional library routines. - (line 841) -* __fractusqda: Fixed-point fractional library routines. - (line 730) -* __fractusqdf: Fixed-point fractional library routines. - (line 753) -* __fractusqdi: Fixed-point fractional library routines. - (line 750) -* __fractusqdq: Fixed-point fractional library routines. - (line 726) -* __fractusqha: Fixed-point fractional library routines. - (line 728) -* __fractusqhi: Fixed-point fractional library routines. - (line 748) -* __fractusqhq: Fixed-point fractional library routines. - (line 724) -* __fractusqqi: Fixed-point fractional library routines. - (line 747) -* __fractusqqq: Fixed-point fractional library routines. - (line 723) -* __fractusqsa: Fixed-point fractional library routines. - (line 729) -* __fractusqsf: Fixed-point fractional library routines. - (line 752) -* __fractusqsi: Fixed-point fractional library routines. - (line 749) -* __fractusqsq: Fixed-point fractional library routines. - (line 725) -* __fractusqta: Fixed-point fractional library routines. - (line 731) -* __fractusqti: Fixed-point fractional library routines. - (line 751) -* __fractusquda: Fixed-point fractional library routines. - (line 743) -* __fractusqudq2: Fixed-point fractional library routines. - (line 737) -* __fractusquha: Fixed-point fractional library routines. - (line 739) -* __fractusquhq2: Fixed-point fractional library routines. - (line 735) -* __fractusquqq2: Fixed-point fractional library routines. - (line 733) -* __fractusqusa: Fixed-point fractional library routines. - (line 741) -* __fractusquta: Fixed-point fractional library routines. - (line 745) -* __fractutada: Fixed-point fractional library routines. - (line 891) -* __fractutadf: Fixed-point fractional library routines. - (line 917) -* __fractutadi: Fixed-point fractional library routines. - (line 913) -* __fractutadq: Fixed-point fractional library routines. - (line 886) -* __fractutaha: Fixed-point fractional library routines. - (line 888) -* __fractutahi: Fixed-point fractional library routines. - (line 911) -* __fractutahq: Fixed-point fractional library routines. - (line 883) -* __fractutaqi: Fixed-point fractional library routines. - (line 909) -* __fractutaqq: Fixed-point fractional library routines. - (line 881) -* __fractutasa: Fixed-point fractional library routines. - (line 890) -* __fractutasf: Fixed-point fractional library routines. - (line 916) -* __fractutasi: Fixed-point fractional library routines. - (line 912) -* __fractutasq: Fixed-point fractional library routines. - (line 884) -* __fractutata: Fixed-point fractional library routines. - (line 893) -* __fractutati: Fixed-point fractional library routines. - (line 914) -* __fractutauda2: Fixed-point fractional library routines. - (line 907) -* __fractutaudq: Fixed-point fractional library routines. - (line 901) -* __fractutauha2: Fixed-point fractional library routines. - (line 903) -* __fractutauhq: Fixed-point fractional library routines. - (line 897) -* __fractutauqq: Fixed-point fractional library routines. - (line 895) -* __fractutausa2: Fixed-point fractional library routines. - (line 905) -* __fractutausq: Fixed-point fractional library routines. - (line 899) -* __gedf2: Soft float library routines. - (line 205) -* __gesf2: Soft float library routines. - (line 204) -* __getf2: Soft float library routines. - (line 206) -* __gtdf2: Soft float library routines. - (line 223) -* __gtsf2: Soft float library routines. - (line 222) -* __gttf2: Soft float library routines. - (line 224) -* __ledf2: Soft float library routines. - (line 217) -* __lesf2: Soft float library routines. - (line 216) -* __letf2: Soft float library routines. - (line 218) -* __lshrdi3: Integer library routines. - (line 30) -* __lshrsi3: Integer library routines. - (line 29) -* __lshrti3: Integer library routines. - (line 31) -* __lshruda3: Fixed-point fractional library routines. - (line 388) -* __lshrudq3: Fixed-point fractional library routines. - (line 382) -* __lshruha3: Fixed-point fractional library routines. - (line 384) -* __lshruhq3: Fixed-point fractional library routines. - (line 378) -* __lshruqq3: Fixed-point fractional library routines. - (line 376) -* __lshrusa3: Fixed-point fractional library routines. - (line 386) -* __lshrusq3: Fixed-point fractional library routines. - (line 380) -* __lshruta3: Fixed-point fractional library routines. - (line 390) -* __ltdf2: Soft float library routines. - (line 211) -* __ltsf2: Soft float library routines. - (line 210) -* __lttf2: Soft float library routines. - (line 212) -* __main: Collect2. (line 15) -* __moddi3: Integer library routines. - (line 36) -* __modsi3: Integer library routines. - (line 35) -* __modti3: Integer library routines. - (line 37) -* __morestack_current_segment: Miscellaneous routines. - (line 45) -* __morestack_initial_sp: Miscellaneous routines. - (line 46) -* __morestack_segments: Miscellaneous routines. - (line 44) -* __mulda3: Fixed-point fractional library routines. - (line 170) -* __muldc3: Soft float library routines. - (line 239) -* __muldf3: Soft float library routines. - (line 39) -* __muldi3: Integer library routines. - (line 42) -* __muldq3: Fixed-point fractional library routines. - (line 157) -* __mulha3: Fixed-point fractional library routines. - (line 167) -* __mulhq3: Fixed-point fractional library routines. - (line 155) -* __mulqq3: Fixed-point fractional library routines. - (line 153) -* __mulsa3: Fixed-point fractional library routines. - (line 169) -* __mulsc3: Soft float library routines. - (line 237) -* __mulsf3: Soft float library routines. - (line 38) -* __mulsi3: Integer library routines. - (line 41) -* __mulsq3: Fixed-point fractional library routines. - (line 156) -* __multa3: Fixed-point fractional library routines. - (line 171) -* __multc3: Soft float library routines. - (line 241) -* __multf3: Soft float library routines. - (line 40) -* __multi3: Integer library routines. - (line 43) -* __muluda3: Fixed-point fractional library routines. - (line 177) -* __muludq3: Fixed-point fractional library routines. - (line 165) -* __muluha3: Fixed-point fractional library routines. - (line 173) -* __muluhq3: Fixed-point fractional library routines. - (line 161) -* __muluqq3: Fixed-point fractional library routines. - (line 159) -* __mulusa3: Fixed-point fractional library routines. - (line 175) -* __mulusq3: Fixed-point fractional library routines. - (line 163) -* __muluta3: Fixed-point fractional library routines. - (line 179) -* __mulvdi3: Integer library routines. - (line 114) -* __mulvsi3: Integer library routines. - (line 113) -* __mulxc3: Soft float library routines. - (line 243) -* __mulxf3: Soft float library routines. - (line 42) -* __nedf2: Soft float library routines. - (line 199) -* __negda2: Fixed-point fractional library routines. - (line 298) -* __negdf2: Soft float library routines. - (line 55) -* __negdi2: Integer library routines. - (line 46) -* __negdq2: Fixed-point fractional library routines. - (line 288) -* __negha2: Fixed-point fractional library routines. - (line 296) -* __neghq2: Fixed-point fractional library routines. - (line 286) -* __negqq2: Fixed-point fractional library routines. - (line 285) -* __negsa2: Fixed-point fractional library routines. - (line 297) -* __negsf2: Soft float library routines. - (line 54) -* __negsq2: Fixed-point fractional library routines. - (line 287) -* __negta2: Fixed-point fractional library routines. - (line 299) -* __negtf2: Soft float library routines. - (line 56) -* __negti2: Integer library routines. - (line 47) -* __neguda2: Fixed-point fractional library routines. - (line 303) -* __negudq2: Fixed-point fractional library routines. - (line 294) -* __neguha2: Fixed-point fractional library routines. - (line 300) -* __neguhq2: Fixed-point fractional library routines. - (line 291) -* __neguqq2: Fixed-point fractional library routines. - (line 289) -* __negusa2: Fixed-point fractional library routines. - (line 302) -* __negusq2: Fixed-point fractional library routines. - (line 292) -* __neguta2: Fixed-point fractional library routines. - (line 305) -* __negvdi2: Integer library routines. - (line 118) -* __negvsi2: Integer library routines. - (line 117) -* __negxf2: Soft float library routines. - (line 57) -* __nesf2: Soft float library routines. - (line 198) -* __netf2: Soft float library routines. - (line 200) -* __paritydi2: Integer library routines. - (line 150) -* __paritysi2: Integer library routines. - (line 149) -* __parityti2: Integer library routines. - (line 151) -* __popcountdi2: Integer library routines. - (line 156) -* __popcountsi2: Integer library routines. - (line 155) -* __popcountti2: Integer library routines. - (line 157) -* __powidf2: Soft float library routines. - (line 232) -* __powisf2: Soft float library routines. - (line 231) -* __powitf2: Soft float library routines. - (line 233) -* __powixf2: Soft float library routines. - (line 234) -* __satfractdadq: Fixed-point fractional library routines. - (line 1152) -* __satfractdaha2: Fixed-point fractional library routines. - (line 1153) -* __satfractdahq: Fixed-point fractional library routines. - (line 1150) -* __satfractdaqq: Fixed-point fractional library routines. - (line 1149) -* __satfractdasa2: Fixed-point fractional library routines. - (line 1154) -* __satfractdasq: Fixed-point fractional library routines. - (line 1151) -* __satfractdata2: Fixed-point fractional library routines. - (line 1155) -* __satfractdauda: Fixed-point fractional library routines. - (line 1165) -* __satfractdaudq: Fixed-point fractional library routines. - (line 1160) -* __satfractdauha: Fixed-point fractional library routines. - (line 1162) -* __satfractdauhq: Fixed-point fractional library routines. - (line 1158) -* __satfractdauqq: Fixed-point fractional library routines. - (line 1156) -* __satfractdausa: Fixed-point fractional library routines. - (line 1164) -* __satfractdausq: Fixed-point fractional library routines. - (line 1159) -* __satfractdauta: Fixed-point fractional library routines. - (line 1166) -* __satfractdfda: Fixed-point fractional library routines. - (line 1505) -* __satfractdfdq: Fixed-point fractional library routines. - (line 1502) -* __satfractdfha: Fixed-point fractional library routines. - (line 1503) -* __satfractdfhq: Fixed-point fractional library routines. - (line 1500) -* __satfractdfqq: Fixed-point fractional library routines. - (line 1499) -* __satfractdfsa: Fixed-point fractional library routines. - (line 1504) -* __satfractdfsq: Fixed-point fractional library routines. - (line 1501) -* __satfractdfta: Fixed-point fractional library routines. - (line 1506) -* __satfractdfuda: Fixed-point fractional library routines. - (line 1514) -* __satfractdfudq: Fixed-point fractional library routines. - (line 1510) -* __satfractdfuha: Fixed-point fractional library routines. - (line 1512) -* __satfractdfuhq: Fixed-point fractional library routines. - (line 1508) -* __satfractdfuqq: Fixed-point fractional library routines. - (line 1507) -* __satfractdfusa: Fixed-point fractional library routines. - (line 1513) -* __satfractdfusq: Fixed-point fractional library routines. - (line 1509) -* __satfractdfuta: Fixed-point fractional library routines. - (line 1515) -* __satfractdida: Fixed-point fractional library routines. - (line 1455) -* __satfractdidq: Fixed-point fractional library routines. - (line 1452) -* __satfractdiha: Fixed-point fractional library routines. - (line 1453) -* __satfractdihq: Fixed-point fractional library routines. - (line 1450) -* __satfractdiqq: Fixed-point fractional library routines. - (line 1449) -* __satfractdisa: Fixed-point fractional library routines. - (line 1454) -* __satfractdisq: Fixed-point fractional library routines. - (line 1451) -* __satfractdita: Fixed-point fractional library routines. - (line 1456) -* __satfractdiuda: Fixed-point fractional library routines. - (line 1463) -* __satfractdiudq: Fixed-point fractional library routines. - (line 1460) -* __satfractdiuha: Fixed-point fractional library routines. - (line 1461) -* __satfractdiuhq: Fixed-point fractional library routines. - (line 1458) -* __satfractdiuqq: Fixed-point fractional library routines. - (line 1457) -* __satfractdiusa: Fixed-point fractional library routines. - (line 1462) -* __satfractdiusq: Fixed-point fractional library routines. - (line 1459) -* __satfractdiuta: Fixed-point fractional library routines. - (line 1464) -* __satfractdqda: Fixed-point fractional library routines. - (line 1097) -* __satfractdqha: Fixed-point fractional library routines. - (line 1095) -* __satfractdqhq2: Fixed-point fractional library routines. - (line 1093) -* __satfractdqqq2: Fixed-point fractional library routines. - (line 1092) -* __satfractdqsa: Fixed-point fractional library routines. - (line 1096) -* __satfractdqsq2: Fixed-point fractional library routines. - (line 1094) -* __satfractdqta: Fixed-point fractional library routines. - (line 1098) -* __satfractdquda: Fixed-point fractional library routines. - (line 1109) -* __satfractdqudq: Fixed-point fractional library routines. - (line 1104) -* __satfractdquha: Fixed-point fractional library routines. - (line 1106) -* __satfractdquhq: Fixed-point fractional library routines. - (line 1101) -* __satfractdquqq: Fixed-point fractional library routines. - (line 1099) -* __satfractdqusa: Fixed-point fractional library routines. - (line 1108) -* __satfractdqusq: Fixed-point fractional library routines. - (line 1102) -* __satfractdquta: Fixed-point fractional library routines. - (line 1111) -* __satfracthada2: Fixed-point fractional library routines. - (line 1118) -* __satfracthadq: Fixed-point fractional library routines. - (line 1116) -* __satfracthahq: Fixed-point fractional library routines. - (line 1114) -* __satfracthaqq: Fixed-point fractional library routines. - (line 1113) -* __satfracthasa2: Fixed-point fractional library routines. - (line 1117) -* __satfracthasq: Fixed-point fractional library routines. - (line 1115) -* __satfracthata2: Fixed-point fractional library routines. - (line 1119) -* __satfracthauda: Fixed-point fractional library routines. - (line 1130) -* __satfracthaudq: Fixed-point fractional library routines. - (line 1125) -* __satfracthauha: Fixed-point fractional library routines. - (line 1127) -* __satfracthauhq: Fixed-point fractional library routines. - (line 1122) -* __satfracthauqq: Fixed-point fractional library routines. - (line 1120) -* __satfracthausa: Fixed-point fractional library routines. - (line 1129) -* __satfracthausq: Fixed-point fractional library routines. - (line 1123) -* __satfracthauta: Fixed-point fractional library routines. - (line 1132) -* __satfracthida: Fixed-point fractional library routines. - (line 1423) -* __satfracthidq: Fixed-point fractional library routines. - (line 1420) -* __satfracthiha: Fixed-point fractional library routines. - (line 1421) -* __satfracthihq: Fixed-point fractional library routines. - (line 1418) -* __satfracthiqq: Fixed-point fractional library routines. - (line 1417) -* __satfracthisa: Fixed-point fractional library routines. - (line 1422) -* __satfracthisq: Fixed-point fractional library routines. - (line 1419) -* __satfracthita: Fixed-point fractional library routines. - (line 1424) -* __satfracthiuda: Fixed-point fractional library routines. - (line 1431) -* __satfracthiudq: Fixed-point fractional library routines. - (line 1428) -* __satfracthiuha: Fixed-point fractional library routines. - (line 1429) -* __satfracthiuhq: Fixed-point fractional library routines. - (line 1426) -* __satfracthiuqq: Fixed-point fractional library routines. - (line 1425) -* __satfracthiusa: Fixed-point fractional library routines. - (line 1430) -* __satfracthiusq: Fixed-point fractional library routines. - (line 1427) -* __satfracthiuta: Fixed-point fractional library routines. - (line 1432) -* __satfracthqda: Fixed-point fractional library routines. - (line 1063) -* __satfracthqdq2: Fixed-point fractional library routines. - (line 1060) -* __satfracthqha: Fixed-point fractional library routines. - (line 1061) -* __satfracthqqq2: Fixed-point fractional library routines. - (line 1058) -* __satfracthqsa: Fixed-point fractional library routines. - (line 1062) -* __satfracthqsq2: Fixed-point fractional library routines. - (line 1059) -* __satfracthqta: Fixed-point fractional library routines. - (line 1064) -* __satfracthquda: Fixed-point fractional library routines. - (line 1071) -* __satfracthqudq: Fixed-point fractional library routines. - (line 1068) -* __satfracthquha: Fixed-point fractional library routines. - (line 1069) -* __satfracthquhq: Fixed-point fractional library routines. - (line 1066) -* __satfracthquqq: Fixed-point fractional library routines. - (line 1065) -* __satfracthqusa: Fixed-point fractional library routines. - (line 1070) -* __satfracthqusq: Fixed-point fractional library routines. - (line 1067) -* __satfracthquta: Fixed-point fractional library routines. - (line 1072) -* __satfractqida: Fixed-point fractional library routines. - (line 1401) -* __satfractqidq: Fixed-point fractional library routines. - (line 1398) -* __satfractqiha: Fixed-point fractional library routines. - (line 1399) -* __satfractqihq: Fixed-point fractional library routines. - (line 1396) -* __satfractqiqq: Fixed-point fractional library routines. - (line 1395) -* __satfractqisa: Fixed-point fractional library routines. - (line 1400) -* __satfractqisq: Fixed-point fractional library routines. - (line 1397) -* __satfractqita: Fixed-point fractional library routines. - (line 1402) -* __satfractqiuda: Fixed-point fractional library routines. - (line 1413) -* __satfractqiudq: Fixed-point fractional library routines. - (line 1408) -* __satfractqiuha: Fixed-point fractional library routines. - (line 1410) -* __satfractqiuhq: Fixed-point fractional library routines. - (line 1405) -* __satfractqiuqq: Fixed-point fractional library routines. - (line 1403) -* __satfractqiusa: Fixed-point fractional library routines. - (line 1412) -* __satfractqiusq: Fixed-point fractional library routines. - (line 1406) -* __satfractqiuta: Fixed-point fractional library routines. - (line 1415) -* __satfractqqda: Fixed-point fractional library routines. - (line 1042) -* __satfractqqdq2: Fixed-point fractional library routines. - (line 1039) -* __satfractqqha: Fixed-point fractional library routines. - (line 1040) -* __satfractqqhq2: Fixed-point fractional library routines. - (line 1037) -* __satfractqqsa: Fixed-point fractional library routines. - (line 1041) -* __satfractqqsq2: Fixed-point fractional library routines. - (line 1038) -* __satfractqqta: Fixed-point fractional library routines. - (line 1043) -* __satfractqquda: Fixed-point fractional library routines. - (line 1054) -* __satfractqqudq: Fixed-point fractional library routines. - (line 1049) -* __satfractqquha: Fixed-point fractional library routines. - (line 1051) -* __satfractqquhq: Fixed-point fractional library routines. - (line 1046) -* __satfractqquqq: Fixed-point fractional library routines. - (line 1044) -* __satfractqqusa: Fixed-point fractional library routines. - (line 1053) -* __satfractqqusq: Fixed-point fractional library routines. - (line 1047) -* __satfractqquta: Fixed-point fractional library routines. - (line 1056) -* __satfractsada2: Fixed-point fractional library routines. - (line 1139) -* __satfractsadq: Fixed-point fractional library routines. - (line 1137) -* __satfractsaha2: Fixed-point fractional library routines. - (line 1138) -* __satfractsahq: Fixed-point fractional library routines. - (line 1135) -* __satfractsaqq: Fixed-point fractional library routines. - (line 1134) -* __satfractsasq: Fixed-point fractional library routines. - (line 1136) -* __satfractsata2: Fixed-point fractional library routines. - (line 1140) -* __satfractsauda: Fixed-point fractional library routines. - (line 1147) -* __satfractsaudq: Fixed-point fractional library routines. - (line 1144) -* __satfractsauha: Fixed-point fractional library routines. - (line 1145) -* __satfractsauhq: Fixed-point fractional library routines. - (line 1142) -* __satfractsauqq: Fixed-point fractional library routines. - (line 1141) -* __satfractsausa: Fixed-point fractional library routines. - (line 1146) -* __satfractsausq: Fixed-point fractional library routines. - (line 1143) -* __satfractsauta: Fixed-point fractional library routines. - (line 1148) -* __satfractsfda: Fixed-point fractional library routines. - (line 1489) -* __satfractsfdq: Fixed-point fractional library routines. - (line 1486) -* __satfractsfha: Fixed-point fractional library routines. - (line 1487) -* __satfractsfhq: Fixed-point fractional library routines. - (line 1484) -* __satfractsfqq: Fixed-point fractional library routines. - (line 1483) -* __satfractsfsa: Fixed-point fractional library routines. - (line 1488) -* __satfractsfsq: Fixed-point fractional library routines. - (line 1485) -* __satfractsfta: Fixed-point fractional library routines. - (line 1490) -* __satfractsfuda: Fixed-point fractional library routines. - (line 1497) -* __satfractsfudq: Fixed-point fractional library routines. - (line 1494) -* __satfractsfuha: Fixed-point fractional library routines. - (line 1495) -* __satfractsfuhq: Fixed-point fractional library routines. - (line 1492) -* __satfractsfuqq: Fixed-point fractional library routines. - (line 1491) -* __satfractsfusa: Fixed-point fractional library routines. - (line 1496) -* __satfractsfusq: Fixed-point fractional library routines. - (line 1493) -* __satfractsfuta: Fixed-point fractional library routines. - (line 1498) -* __satfractsida: Fixed-point fractional library routines. - (line 1439) -* __satfractsidq: Fixed-point fractional library routines. - (line 1436) -* __satfractsiha: Fixed-point fractional library routines. - (line 1437) -* __satfractsihq: Fixed-point fractional library routines. - (line 1434) -* __satfractsiqq: Fixed-point fractional library routines. - (line 1433) -* __satfractsisa: Fixed-point fractional library routines. - (line 1438) -* __satfractsisq: Fixed-point fractional library routines. - (line 1435) -* __satfractsita: Fixed-point fractional library routines. - (line 1440) -* __satfractsiuda: Fixed-point fractional library routines. - (line 1447) -* __satfractsiudq: Fixed-point fractional library routines. - (line 1444) -* __satfractsiuha: Fixed-point fractional library routines. - (line 1445) -* __satfractsiuhq: Fixed-point fractional library routines. - (line 1442) -* __satfractsiuqq: Fixed-point fractional library routines. - (line 1441) -* __satfractsiusa: Fixed-point fractional library routines. - (line 1446) -* __satfractsiusq: Fixed-point fractional library routines. - (line 1443) -* __satfractsiuta: Fixed-point fractional library routines. - (line 1448) -* __satfractsqda: Fixed-point fractional library routines. - (line 1078) -* __satfractsqdq2: Fixed-point fractional library routines. - (line 1075) -* __satfractsqha: Fixed-point fractional library routines. - (line 1076) -* __satfractsqhq2: Fixed-point fractional library routines. - (line 1074) -* __satfractsqqq2: Fixed-point fractional library routines. - (line 1073) -* __satfractsqsa: Fixed-point fractional library routines. - (line 1077) -* __satfractsqta: Fixed-point fractional library routines. - (line 1079) -* __satfractsquda: Fixed-point fractional library routines. - (line 1089) -* __satfractsqudq: Fixed-point fractional library routines. - (line 1084) -* __satfractsquha: Fixed-point fractional library routines. - (line 1086) -* __satfractsquhq: Fixed-point fractional library routines. - (line 1082) -* __satfractsquqq: Fixed-point fractional library routines. - (line 1080) -* __satfractsqusa: Fixed-point fractional library routines. - (line 1088) -* __satfractsqusq: Fixed-point fractional library routines. - (line 1083) -* __satfractsquta: Fixed-point fractional library routines. - (line 1090) -* __satfracttada2: Fixed-point fractional library routines. - (line 1174) -* __satfracttadq: Fixed-point fractional library routines. - (line 1171) -* __satfracttaha2: Fixed-point fractional library routines. - (line 1172) -* __satfracttahq: Fixed-point fractional library routines. - (line 1169) -* __satfracttaqq: Fixed-point fractional library routines. - (line 1168) -* __satfracttasa2: Fixed-point fractional library routines. - (line 1173) -* __satfracttasq: Fixed-point fractional library routines. - (line 1170) -* __satfracttauda: Fixed-point fractional library routines. - (line 1185) -* __satfracttaudq: Fixed-point fractional library routines. - (line 1180) -* __satfracttauha: Fixed-point fractional library routines. - (line 1182) -* __satfracttauhq: Fixed-point fractional library routines. - (line 1177) -* __satfracttauqq: Fixed-point fractional library routines. - (line 1175) -* __satfracttausa: Fixed-point fractional library routines. - (line 1184) -* __satfracttausq: Fixed-point fractional library routines. - (line 1178) -* __satfracttauta: Fixed-point fractional library routines. - (line 1187) -* __satfracttida: Fixed-point fractional library routines. - (line 1471) -* __satfracttidq: Fixed-point fractional library routines. - (line 1468) -* __satfracttiha: Fixed-point fractional library routines. - (line 1469) -* __satfracttihq: Fixed-point fractional library routines. - (line 1466) -* __satfracttiqq: Fixed-point fractional library routines. - (line 1465) -* __satfracttisa: Fixed-point fractional library routines. - (line 1470) -* __satfracttisq: Fixed-point fractional library routines. - (line 1467) -* __satfracttita: Fixed-point fractional library routines. - (line 1472) -* __satfracttiuda: Fixed-point fractional library routines. - (line 1480) -* __satfracttiudq: Fixed-point fractional library routines. - (line 1476) -* __satfracttiuha: Fixed-point fractional library routines. - (line 1478) -* __satfracttiuhq: Fixed-point fractional library routines. - (line 1474) -* __satfracttiuqq: Fixed-point fractional library routines. - (line 1473) -* __satfracttiusa: Fixed-point fractional library routines. - (line 1479) -* __satfracttiusq: Fixed-point fractional library routines. - (line 1475) -* __satfracttiuta: Fixed-point fractional library routines. - (line 1481) -* __satfractudada: Fixed-point fractional library routines. - (line 1350) -* __satfractudadq: Fixed-point fractional library routines. - (line 1345) -* __satfractudaha: Fixed-point fractional library routines. - (line 1347) -* __satfractudahq: Fixed-point fractional library routines. - (line 1343) -* __satfractudaqq: Fixed-point fractional library routines. - (line 1341) -* __satfractudasa: Fixed-point fractional library routines. - (line 1349) -* __satfractudasq: Fixed-point fractional library routines. - (line 1344) -* __satfractudata: Fixed-point fractional library routines. - (line 1351) -* __satfractudaudq: Fixed-point fractional library routines. - (line 1359) -* __satfractudauha2: Fixed-point fractional library routines. - (line 1361) -* __satfractudauhq: Fixed-point fractional library routines. - (line 1355) -* __satfractudauqq: Fixed-point fractional library routines. - (line 1353) -* __satfractudausa2: Fixed-point fractional library routines. - (line 1363) -* __satfractudausq: Fixed-point fractional library routines. - (line 1357) -* __satfractudauta2: Fixed-point fractional library routines. - (line 1365) -* __satfractudqda: Fixed-point fractional library routines. - (line 1274) -* __satfractudqdq: Fixed-point fractional library routines. - (line 1269) -* __satfractudqha: Fixed-point fractional library routines. - (line 1271) -* __satfractudqhq: Fixed-point fractional library routines. - (line 1266) -* __satfractudqqq: Fixed-point fractional library routines. - (line 1264) -* __satfractudqsa: Fixed-point fractional library routines. - (line 1273) -* __satfractudqsq: Fixed-point fractional library routines. - (line 1267) -* __satfractudqta: Fixed-point fractional library routines. - (line 1276) -* __satfractudquda: Fixed-point fractional library routines. - (line 1288) -* __satfractudquha: Fixed-point fractional library routines. - (line 1284) -* __satfractudquhq2: Fixed-point fractional library routines. - (line 1280) -* __satfractudquqq2: Fixed-point fractional library routines. - (line 1278) -* __satfractudqusa: Fixed-point fractional library routines. - (line 1286) -* __satfractudqusq2: Fixed-point fractional library routines. - (line 1282) -* __satfractudquta: Fixed-point fractional library routines. - (line 1290) -* __satfractuhada: Fixed-point fractional library routines. - (line 1302) -* __satfractuhadq: Fixed-point fractional library routines. - (line 1297) -* __satfractuhaha: Fixed-point fractional library routines. - (line 1299) -* __satfractuhahq: Fixed-point fractional library routines. - (line 1294) -* __satfractuhaqq: Fixed-point fractional library routines. - (line 1292) -* __satfractuhasa: Fixed-point fractional library routines. - (line 1301) -* __satfractuhasq: Fixed-point fractional library routines. - (line 1295) -* __satfractuhata: Fixed-point fractional library routines. - (line 1304) -* __satfractuhauda2: Fixed-point fractional library routines. - (line 1316) -* __satfractuhaudq: Fixed-point fractional library routines. - (line 1312) -* __satfractuhauhq: Fixed-point fractional library routines. - (line 1308) -* __satfractuhauqq: Fixed-point fractional library routines. - (line 1306) -* __satfractuhausa2: Fixed-point fractional library routines. - (line 1314) -* __satfractuhausq: Fixed-point fractional library routines. - (line 1310) -* __satfractuhauta2: Fixed-point fractional library routines. - (line 1318) -* __satfractuhqda: Fixed-point fractional library routines. - (line 1223) -* __satfractuhqdq: Fixed-point fractional library routines. - (line 1220) -* __satfractuhqha: Fixed-point fractional library routines. - (line 1221) -* __satfractuhqhq: Fixed-point fractional library routines. - (line 1218) -* __satfractuhqqq: Fixed-point fractional library routines. - (line 1217) -* __satfractuhqsa: Fixed-point fractional library routines. - (line 1222) -* __satfractuhqsq: Fixed-point fractional library routines. - (line 1219) -* __satfractuhqta: Fixed-point fractional library routines. - (line 1224) -* __satfractuhquda: Fixed-point fractional library routines. - (line 1234) -* __satfractuhqudq2: Fixed-point fractional library routines. - (line 1229) -* __satfractuhquha: Fixed-point fractional library routines. - (line 1231) -* __satfractuhquqq2: Fixed-point fractional library routines. - (line 1225) -* __satfractuhqusa: Fixed-point fractional library routines. - (line 1233) -* __satfractuhqusq2: Fixed-point fractional library routines. - (line 1227) -* __satfractuhquta: Fixed-point fractional library routines. - (line 1236) -* __satfractunsdida: Fixed-point fractional library routines. - (line 1833) -* __satfractunsdidq: Fixed-point fractional library routines. - (line 1829) -* __satfractunsdiha: Fixed-point fractional library routines. - (line 1831) -* __satfractunsdihq: Fixed-point fractional library routines. - (line 1827) -* __satfractunsdiqq: Fixed-point fractional library routines. - (line 1826) -* __satfractunsdisa: Fixed-point fractional library routines. - (line 1832) -* __satfractunsdisq: Fixed-point fractional library routines. - (line 1828) -* __satfractunsdita: Fixed-point fractional library routines. - (line 1834) -* __satfractunsdiuda: Fixed-point fractional library routines. - (line 1848) -* __satfractunsdiudq: Fixed-point fractional library routines. - (line 1842) -* __satfractunsdiuha: Fixed-point fractional library routines. - (line 1844) -* __satfractunsdiuhq: Fixed-point fractional library routines. - (line 1838) -* __satfractunsdiuqq: Fixed-point fractional library routines. - (line 1836) -* __satfractunsdiusa: Fixed-point fractional library routines. - (line 1846) -* __satfractunsdiusq: Fixed-point fractional library routines. - (line 1840) -* __satfractunsdiuta: Fixed-point fractional library routines. - (line 1850) -* __satfractunshida: Fixed-point fractional library routines. - (line 1785) -* __satfractunshidq: Fixed-point fractional library routines. - (line 1781) -* __satfractunshiha: Fixed-point fractional library routines. - (line 1783) -* __satfractunshihq: Fixed-point fractional library routines. - (line 1779) -* __satfractunshiqq: Fixed-point fractional library routines. - (line 1778) -* __satfractunshisa: Fixed-point fractional library routines. - (line 1784) -* __satfractunshisq: Fixed-point fractional library routines. - (line 1780) -* __satfractunshita: Fixed-point fractional library routines. - (line 1786) -* __satfractunshiuda: Fixed-point fractional library routines. - (line 1800) -* __satfractunshiudq: Fixed-point fractional library routines. - (line 1794) -* __satfractunshiuha: Fixed-point fractional library routines. - (line 1796) -* __satfractunshiuhq: Fixed-point fractional library routines. - (line 1790) -* __satfractunshiuqq: Fixed-point fractional library routines. - (line 1788) -* __satfractunshiusa: Fixed-point fractional library routines. - (line 1798) -* __satfractunshiusq: Fixed-point fractional library routines. - (line 1792) -* __satfractunshiuta: Fixed-point fractional library routines. - (line 1802) -* __satfractunsqida: Fixed-point fractional library routines. - (line 1759) -* __satfractunsqidq: Fixed-point fractional library routines. - (line 1755) -* __satfractunsqiha: Fixed-point fractional library routines. - (line 1757) -* __satfractunsqihq: Fixed-point fractional library routines. - (line 1753) -* __satfractunsqiqq: Fixed-point fractional library routines. - (line 1752) -* __satfractunsqisa: Fixed-point fractional library routines. - (line 1758) -* __satfractunsqisq: Fixed-point fractional library routines. - (line 1754) -* __satfractunsqita: Fixed-point fractional library routines. - (line 1760) -* __satfractunsqiuda: Fixed-point fractional library routines. - (line 1774) -* __satfractunsqiudq: Fixed-point fractional library routines. - (line 1768) -* __satfractunsqiuha: Fixed-point fractional library routines. - (line 1770) -* __satfractunsqiuhq: Fixed-point fractional library routines. - (line 1764) -* __satfractunsqiuqq: Fixed-point fractional library routines. - (line 1762) -* __satfractunsqiusa: Fixed-point fractional library routines. - (line 1772) -* __satfractunsqiusq: Fixed-point fractional library routines. - (line 1766) -* __satfractunsqiuta: Fixed-point fractional library routines. - (line 1776) -* __satfractunssida: Fixed-point fractional library routines. - (line 1810) -* __satfractunssidq: Fixed-point fractional library routines. - (line 1807) -* __satfractunssiha: Fixed-point fractional library routines. - (line 1808) -* __satfractunssihq: Fixed-point fractional library routines. - (line 1805) -* __satfractunssiqq: Fixed-point fractional library routines. - (line 1804) -* __satfractunssisa: Fixed-point fractional library routines. - (line 1809) -* __satfractunssisq: Fixed-point fractional library routines. - (line 1806) -* __satfractunssita: Fixed-point fractional library routines. - (line 1811) -* __satfractunssiuda: Fixed-point fractional library routines. - (line 1822) -* __satfractunssiudq: Fixed-point fractional library routines. - (line 1817) -* __satfractunssiuha: Fixed-point fractional library routines. - (line 1819) -* __satfractunssiuhq: Fixed-point fractional library routines. - (line 1814) -* __satfractunssiuqq: Fixed-point fractional library routines. - (line 1812) -* __satfractunssiusa: Fixed-point fractional library routines. - (line 1821) -* __satfractunssiusq: Fixed-point fractional library routines. - (line 1815) -* __satfractunssiuta: Fixed-point fractional library routines. - (line 1824) -* __satfractunstida: Fixed-point fractional library routines. - (line 1862) -* __satfractunstidq: Fixed-point fractional library routines. - (line 1857) -* __satfractunstiha: Fixed-point fractional library routines. - (line 1859) -* __satfractunstihq: Fixed-point fractional library routines. - (line 1854) -* __satfractunstiqq: Fixed-point fractional library routines. - (line 1852) -* __satfractunstisa: Fixed-point fractional library routines. - (line 1861) -* __satfractunstisq: Fixed-point fractional library routines. - (line 1855) -* __satfractunstita: Fixed-point fractional library routines. - (line 1864) -* __satfractunstiuda: Fixed-point fractional library routines. - (line 1878) -* __satfractunstiudq: Fixed-point fractional library routines. - (line 1872) -* __satfractunstiuha: Fixed-point fractional library routines. - (line 1874) -* __satfractunstiuhq: Fixed-point fractional library routines. - (line 1868) -* __satfractunstiuqq: Fixed-point fractional library routines. - (line 1866) -* __satfractunstiusa: Fixed-point fractional library routines. - (line 1876) -* __satfractunstiusq: Fixed-point fractional library routines. - (line 1870) -* __satfractunstiuta: Fixed-point fractional library routines. - (line 1880) -* __satfractuqqda: Fixed-point fractional library routines. - (line 1199) -* __satfractuqqdq: Fixed-point fractional library routines. - (line 1194) -* __satfractuqqha: Fixed-point fractional library routines. - (line 1196) -* __satfractuqqhq: Fixed-point fractional library routines. - (line 1191) -* __satfractuqqqq: Fixed-point fractional library routines. - (line 1189) -* __satfractuqqsa: Fixed-point fractional library routines. - (line 1198) -* __satfractuqqsq: Fixed-point fractional library routines. - (line 1192) -* __satfractuqqta: Fixed-point fractional library routines. - (line 1201) -* __satfractuqquda: Fixed-point fractional library routines. - (line 1213) -* __satfractuqqudq2: Fixed-point fractional library routines. - (line 1207) -* __satfractuqquha: Fixed-point fractional library routines. - (line 1209) -* __satfractuqquhq2: Fixed-point fractional library routines. - (line 1203) -* __satfractuqqusa: Fixed-point fractional library routines. - (line 1211) -* __satfractuqqusq2: Fixed-point fractional library routines. - (line 1205) -* __satfractuqquta: Fixed-point fractional library routines. - (line 1215) -* __satfractusada: Fixed-point fractional library routines. - (line 1326) -* __satfractusadq: Fixed-point fractional library routines. - (line 1323) -* __satfractusaha: Fixed-point fractional library routines. - (line 1324) -* __satfractusahq: Fixed-point fractional library routines. - (line 1321) -* __satfractusaqq: Fixed-point fractional library routines. - (line 1320) -* __satfractusasa: Fixed-point fractional library routines. - (line 1325) -* __satfractusasq: Fixed-point fractional library routines. - (line 1322) -* __satfractusata: Fixed-point fractional library routines. - (line 1327) -* __satfractusauda2: Fixed-point fractional library routines. - (line 1337) -* __satfractusaudq: Fixed-point fractional library routines. - (line 1333) -* __satfractusauha2: Fixed-point fractional library routines. - (line 1335) -* __satfractusauhq: Fixed-point fractional library routines. - (line 1330) -* __satfractusauqq: Fixed-point fractional library routines. - (line 1328) -* __satfractusausq: Fixed-point fractional library routines. - (line 1331) -* __satfractusauta2: Fixed-point fractional library routines. - (line 1339) -* __satfractusqda: Fixed-point fractional library routines. - (line 1247) -* __satfractusqdq: Fixed-point fractional library routines. - (line 1242) -* __satfractusqha: Fixed-point fractional library routines. - (line 1244) -* __satfractusqhq: Fixed-point fractional library routines. - (line 1240) -* __satfractusqqq: Fixed-point fractional library routines. - (line 1238) -* __satfractusqsa: Fixed-point fractional library routines. - (line 1246) -* __satfractusqsq: Fixed-point fractional library routines. - (line 1241) -* __satfractusqta: Fixed-point fractional library routines. - (line 1248) -* __satfractusquda: Fixed-point fractional library routines. - (line 1260) -* __satfractusqudq2: Fixed-point fractional library routines. - (line 1254) -* __satfractusquha: Fixed-point fractional library routines. - (line 1256) -* __satfractusquhq2: Fixed-point fractional library routines. - (line 1252) -* __satfractusquqq2: Fixed-point fractional library routines. - (line 1250) -* __satfractusqusa: Fixed-point fractional library routines. - (line 1258) -* __satfractusquta: Fixed-point fractional library routines. - (line 1262) -* __satfractutada: Fixed-point fractional library routines. - (line 1377) -* __satfractutadq: Fixed-point fractional library routines. - (line 1372) -* __satfractutaha: Fixed-point fractional library routines. - (line 1374) -* __satfractutahq: Fixed-point fractional library routines. - (line 1369) -* __satfractutaqq: Fixed-point fractional library routines. - (line 1367) -* __satfractutasa: Fixed-point fractional library routines. - (line 1376) -* __satfractutasq: Fixed-point fractional library routines. - (line 1370) -* __satfractutata: Fixed-point fractional library routines. - (line 1379) -* __satfractutauda2: Fixed-point fractional library routines. - (line 1393) -* __satfractutaudq: Fixed-point fractional library routines. - (line 1387) -* __satfractutauha2: Fixed-point fractional library routines. - (line 1389) -* __satfractutauhq: Fixed-point fractional library routines. - (line 1383) -* __satfractutauqq: Fixed-point fractional library routines. - (line 1381) -* __satfractutausa2: Fixed-point fractional library routines. - (line 1391) -* __satfractutausq: Fixed-point fractional library routines. - (line 1385) -* __splitstack_find: Miscellaneous routines. - (line 15) -* __ssaddda3: Fixed-point fractional library routines. - (line 66) -* __ssadddq3: Fixed-point fractional library routines. - (line 61) -* __ssaddha3: Fixed-point fractional library routines. - (line 63) -* __ssaddhq3: Fixed-point fractional library routines. - (line 59) -* __ssaddqq3: Fixed-point fractional library routines. - (line 57) -* __ssaddsa3: Fixed-point fractional library routines. - (line 65) -* __ssaddsq3: Fixed-point fractional library routines. - (line 60) -* __ssaddta3: Fixed-point fractional library routines. - (line 67) -* __ssashlda3: Fixed-point fractional library routines. - (line 401) -* __ssashldq3: Fixed-point fractional library routines. - (line 397) -* __ssashlha3: Fixed-point fractional library routines. - (line 399) -* __ssashlhq3: Fixed-point fractional library routines. - (line 395) -* __ssashlsa3: Fixed-point fractional library routines. - (line 400) -* __ssashlsq3: Fixed-point fractional library routines. - (line 396) -* __ssashlta3: Fixed-point fractional library routines. - (line 402) -* __ssdivda3: Fixed-point fractional library routines. - (line 260) -* __ssdivdq3: Fixed-point fractional library routines. - (line 255) -* __ssdivha3: Fixed-point fractional library routines. - (line 257) -* __ssdivhq3: Fixed-point fractional library routines. - (line 253) -* __ssdivqq3: Fixed-point fractional library routines. - (line 251) -* __ssdivsa3: Fixed-point fractional library routines. - (line 259) -* __ssdivsq3: Fixed-point fractional library routines. - (line 254) -* __ssdivta3: Fixed-point fractional library routines. - (line 261) -* __ssmulda3: Fixed-point fractional library routines. - (line 192) -* __ssmuldq3: Fixed-point fractional library routines. - (line 187) -* __ssmulha3: Fixed-point fractional library routines. - (line 189) -* __ssmulhq3: Fixed-point fractional library routines. - (line 185) -* __ssmulqq3: Fixed-point fractional library routines. - (line 183) -* __ssmulsa3: Fixed-point fractional library routines. - (line 191) -* __ssmulsq3: Fixed-point fractional library routines. - (line 186) -* __ssmulta3: Fixed-point fractional library routines. - (line 193) -* __ssnegda2: Fixed-point fractional library routines. - (line 315) -* __ssnegdq2: Fixed-point fractional library routines. - (line 312) -* __ssnegha2: Fixed-point fractional library routines. - (line 313) -* __ssneghq2: Fixed-point fractional library routines. - (line 310) -* __ssnegqq2: Fixed-point fractional library routines. - (line 309) -* __ssnegsa2: Fixed-point fractional library routines. - (line 314) -* __ssnegsq2: Fixed-point fractional library routines. - (line 311) -* __ssnegta2: Fixed-point fractional library routines. - (line 316) -* __sssubda3: Fixed-point fractional library routines. - (line 128) -* __sssubdq3: Fixed-point fractional library routines. - (line 123) -* __sssubha3: Fixed-point fractional library routines. - (line 125) -* __sssubhq3: Fixed-point fractional library routines. - (line 121) -* __sssubqq3: Fixed-point fractional library routines. - (line 119) -* __sssubsa3: Fixed-point fractional library routines. - (line 127) -* __sssubsq3: Fixed-point fractional library routines. - (line 122) -* __sssubta3: Fixed-point fractional library routines. - (line 129) -* __subda3: Fixed-point fractional library routines. - (line 106) -* __subdf3: Soft float library routines. - (line 30) -* __subdq3: Fixed-point fractional library routines. - (line 93) -* __subha3: Fixed-point fractional library routines. - (line 103) -* __subhq3: Fixed-point fractional library routines. - (line 91) -* __subqq3: Fixed-point fractional library routines. - (line 89) -* __subsa3: Fixed-point fractional library routines. - (line 105) -* __subsf3: Soft float library routines. - (line 29) -* __subsq3: Fixed-point fractional library routines. - (line 92) -* __subta3: Fixed-point fractional library routines. - (line 107) -* __subtf3: Soft float library routines. - (line 31) -* __subuda3: Fixed-point fractional library routines. - (line 113) -* __subudq3: Fixed-point fractional library routines. - (line 101) -* __subuha3: Fixed-point fractional library routines. - (line 109) -* __subuhq3: Fixed-point fractional library routines. - (line 97) -* __subuqq3: Fixed-point fractional library routines. - (line 95) -* __subusa3: Fixed-point fractional library routines. - (line 111) -* __subusq3: Fixed-point fractional library routines. - (line 99) -* __subuta3: Fixed-point fractional library routines. - (line 115) -* __subvdi3: Integer library routines. - (line 122) -* __subvsi3: Integer library routines. - (line 121) -* __subxf3: Soft float library routines. - (line 33) -* __truncdfsf2: Soft float library routines. - (line 75) -* __trunctfdf2: Soft float library routines. - (line 72) -* __trunctfsf2: Soft float library routines. - (line 74) -* __truncxfdf2: Soft float library routines. - (line 71) -* __truncxfsf2: Soft float library routines. - (line 73) -* __ucmpdi2: Integer library routines. - (line 92) -* __ucmpti2: Integer library routines. - (line 93) -* __udivdi3: Integer library routines. - (line 52) -* __udivmoddi4: Integer library routines. - (line 59) -* __udivmodti4: Integer library routines. - (line 61) -* __udivsi3: Integer library routines. - (line 50) -* __udivti3: Integer library routines. - (line 54) -* __udivuda3: Fixed-point fractional library routines. - (line 244) -* __udivudq3: Fixed-point fractional library routines. - (line 238) -* __udivuha3: Fixed-point fractional library routines. - (line 240) -* __udivuhq3: Fixed-point fractional library routines. - (line 234) -* __udivuqq3: Fixed-point fractional library routines. - (line 232) -* __udivusa3: Fixed-point fractional library routines. - (line 242) -* __udivusq3: Fixed-point fractional library routines. - (line 236) -* __udivuta3: Fixed-point fractional library routines. - (line 246) -* __umoddi3: Integer library routines. - (line 69) -* __umodsi3: Integer library routines. - (line 67) -* __umodti3: Integer library routines. - (line 71) -* __unorddf2: Soft float library routines. - (line 172) -* __unordsf2: Soft float library routines. - (line 171) -* __unordtf2: Soft float library routines. - (line 173) -* __usadduda3: Fixed-point fractional library routines. - (line 83) -* __usaddudq3: Fixed-point fractional library routines. - (line 77) -* __usadduha3: Fixed-point fractional library routines. - (line 79) -* __usadduhq3: Fixed-point fractional library routines. - (line 73) -* __usadduqq3: Fixed-point fractional library routines. - (line 71) -* __usaddusa3: Fixed-point fractional library routines. - (line 81) -* __usaddusq3: Fixed-point fractional library routines. - (line 75) -* __usadduta3: Fixed-point fractional library routines. - (line 85) -* __usashluda3: Fixed-point fractional library routines. - (line 419) -* __usashludq3: Fixed-point fractional library routines. - (line 413) -* __usashluha3: Fixed-point fractional library routines. - (line 415) -* __usashluhq3: Fixed-point fractional library routines. - (line 409) -* __usashluqq3: Fixed-point fractional library routines. - (line 407) -* __usashlusa3: Fixed-point fractional library routines. - (line 417) -* __usashlusq3: Fixed-point fractional library routines. - (line 411) -* __usashluta3: Fixed-point fractional library routines. - (line 421) -* __usdivuda3: Fixed-point fractional library routines. - (line 278) -* __usdivudq3: Fixed-point fractional library routines. - (line 272) -* __usdivuha3: Fixed-point fractional library routines. - (line 274) -* __usdivuhq3: Fixed-point fractional library routines. - (line 268) -* __usdivuqq3: Fixed-point fractional library routines. - (line 266) -* __usdivusa3: Fixed-point fractional library routines. - (line 276) -* __usdivusq3: Fixed-point fractional library routines. - (line 270) -* __usdivuta3: Fixed-point fractional library routines. - (line 280) -* __usmuluda3: Fixed-point fractional library routines. - (line 210) -* __usmuludq3: Fixed-point fractional library routines. - (line 204) -* __usmuluha3: Fixed-point fractional library routines. - (line 206) -* __usmuluhq3: Fixed-point fractional library routines. - (line 200) -* __usmuluqq3: Fixed-point fractional library routines. - (line 198) -* __usmulusa3: Fixed-point fractional library routines. - (line 208) -* __usmulusq3: Fixed-point fractional library routines. - (line 202) -* __usmuluta3: Fixed-point fractional library routines. - (line 212) -* __usneguda2: Fixed-point fractional library routines. - (line 329) -* __usnegudq2: Fixed-point fractional library routines. - (line 324) -* __usneguha2: Fixed-point fractional library routines. - (line 326) -* __usneguhq2: Fixed-point fractional library routines. - (line 321) -* __usneguqq2: Fixed-point fractional library routines. - (line 319) -* __usnegusa2: Fixed-point fractional library routines. - (line 328) -* __usnegusq2: Fixed-point fractional library routines. - (line 322) -* __usneguta2: Fixed-point fractional library routines. - (line 331) -* __ussubuda3: Fixed-point fractional library routines. - (line 146) -* __ussubudq3: Fixed-point fractional library routines. - (line 140) -* __ussubuha3: Fixed-point fractional library routines. - (line 142) -* __ussubuhq3: Fixed-point fractional library routines. - (line 136) -* __ussubuqq3: Fixed-point fractional library routines. - (line 134) -* __ussubusa3: Fixed-point fractional library routines. - (line 144) -* __ussubusq3: Fixed-point fractional library routines. - (line 138) -* __ussubuta3: Fixed-point fractional library routines. - (line 148) -* abort: Portability. (line 20) -* abs: Arithmetic. (line 201) -* 'abs' and attributes: Expressions. (line 83) -* absence_set: Processor pipeline description. - (line 223) -* 'absM2' instruction pattern: Standard Names. (line 541) -* absolute value: Arithmetic. (line 201) -* ABS_EXPR: Unary and Binary Expressions. - (line 6) -* access to operands: Accessors. (line 6) -* access to special operands: Special Accessors. (line 6) -* accessors: Accessors. (line 6) -* ACCUMULATE_OUTGOING_ARGS: Stack Arguments. (line 48) -* 'ACCUMULATE_OUTGOING_ARGS' and stack frames: Function Entry. - (line 133) -* ACCUM_TYPE_SIZE: Type Layout. (line 87) -* ADA_LONG_TYPE_SIZE: Type Layout. (line 25) -* Adding a new GIMPLE statement code: Adding a new GIMPLE statement code. - (line 6) -* ADDITIONAL_REGISTER_NAMES: Instruction Output. (line 14) -* 'addM3' instruction pattern: Standard Names. (line 260) -* 'addMODEcc' instruction pattern: Standard Names. (line 1063) -* 'addptrM3' instruction pattern: Standard Names. (line 266) -* address constraints: Simple Constraints. (line 162) -* addressing modes: Addressing Modes. (line 6) -* address_operand: Machine-Independent Predicates. - (line 62) -* address_operand <1>: Simple Constraints. (line 166) -* addr_diff_vec: Side Effects. (line 313) -* 'addr_diff_vec', length of: Insn Lengths. (line 26) -* ADDR_EXPR: Storage References. (line 6) -* addr_vec: Side Effects. (line 308) -* 'addr_vec', length of: Insn Lengths. (line 26) -* ADJUST_FIELD_ALIGN: Storage Layout. (line 190) -* ADJUST_INSN_LENGTH: Insn Lengths. (line 35) -* ADJUST_REG_ALLOC_ORDER: Allocation Order. (line 22) -* aggregates as return values: Aggregate Return. (line 6) -* alias: Alias analysis. (line 6) -* 'allocate_stack' instruction pattern: Standard Names. (line 1377) -* ALL_REGS: Register Classes. (line 17) -* alternate entry points: Insns. (line 146) -* anchored addresses: Anchored Addresses. (line 6) -* and: Arithmetic. (line 159) -* 'and' and attributes: Expressions. (line 50) -* 'and', canonicalization of: Insn Canonicalizations. - (line 51) -* 'andM3' instruction pattern: Standard Names. (line 276) -* ANNOTATE_EXPR: Unary and Binary Expressions. - (line 6) -* annotations: Annotations. (line 6) -* APPLY_RESULT_SIZE: Scalar Return. (line 112) -* ARGS_GROW_DOWNWARD: Frame Layout. (line 34) -* argument passing: Interface. (line 36) -* arguments in registers: Register Arguments. (line 6) -* arguments on stack: Stack Arguments. (line 6) -* ARG_POINTER_CFA_OFFSET: Frame Layout. (line 192) -* ARG_POINTER_REGNUM: Frame Registers. (line 40) -* 'ARG_POINTER_REGNUM' and virtual registers: Regs and Memory. - (line 65) -* arg_pointer_rtx: Frame Registers. (line 104) -* arithmetic library: Soft float library routines. - (line 6) -* arithmetic shift: Arithmetic. (line 174) -* arithmetic shift with signed saturation: Arithmetic. (line 174) -* arithmetic shift with unsigned saturation: Arithmetic. (line 174) -* arithmetic, in RTL: Arithmetic. (line 6) -* ARITHMETIC_TYPE_P: Types for C++. (line 59) -* array: Types. (line 6) -* ARRAY_RANGE_REF: Storage References. (line 6) -* ARRAY_REF: Storage References. (line 6) -* ARRAY_TYPE: Types. (line 6) -* ashift: Arithmetic. (line 174) -* 'ashift' and attributes: Expressions. (line 83) -* ashiftrt: Arithmetic. (line 191) -* 'ashiftrt' and attributes: Expressions. (line 83) -* 'ashlM3' instruction pattern: Standard Names. (line 516) -* 'ashrM3' instruction pattern: Standard Names. (line 526) -* ASM_APP_OFF: File Framework. (line 76) -* ASM_APP_ON: File Framework. (line 69) -* ASM_COMMENT_START: File Framework. (line 64) -* ASM_DECLARE_FUNCTION_NAME: Label Output. (line 108) -* ASM_DECLARE_FUNCTION_SIZE: Label Output. (line 123) -* ASM_DECLARE_OBJECT_NAME: Label Output. (line 136) -* ASM_DECLARE_REGISTER_GLOBAL: Label Output. (line 164) -* ASM_FINAL_SPEC: Driver. (line 81) -* ASM_FINISH_DECLARE_OBJECT: Label Output. (line 172) -* ASM_FORMAT_PRIVATE_NAME: Label Output. (line 391) -* asm_fprintf: Instruction Output. (line 150) -* ASM_FPRINTF_EXTENSIONS: Instruction Output. (line 160) -* ASM_GENERATE_INTERNAL_LABEL: Label Output. (line 375) -* asm_input: Side Effects. (line 295) -* 'asm_input' and '/v': Flags. (line 76) -* ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX: Exception Handling. (line 80) -* asm_noperands: Insns. (line 304) -* ASM_NO_SKIP_IN_TEXT: Alignment Output. (line 78) -* 'asm_operands' and '/v': Flags. (line 76) -* 'asm_operands', RTL sharing: Sharing. (line 45) -* 'asm_operands', usage: Assembler. (line 6) -* ASM_OUTPUT_ADDR_DIFF_ELT: Dispatch Tables. (line 8) -* ASM_OUTPUT_ADDR_VEC_ELT: Dispatch Tables. (line 25) -* ASM_OUTPUT_ALIGN: Alignment Output. (line 85) -* ASM_OUTPUT_ALIGNED_BSS: Uninitialized Data. (line 45) -* ASM_OUTPUT_ALIGNED_COMMON: Uninitialized Data. (line 29) -* ASM_OUTPUT_ALIGNED_DECL_COMMON: Uninitialized Data. (line 36) -* ASM_OUTPUT_ALIGNED_DECL_LOCAL: Uninitialized Data. (line 89) -* ASM_OUTPUT_ALIGNED_LOCAL: Uninitialized Data. (line 82) -* ASM_OUTPUT_ALIGN_WITH_NOP: Alignment Output. (line 90) -* ASM_OUTPUT_ASCII: Data Output. (line 50) -* ASM_OUTPUT_CASE_END: Dispatch Tables. (line 50) -* ASM_OUTPUT_CASE_LABEL: Dispatch Tables. (line 37) -* ASM_OUTPUT_COMMON: Uninitialized Data. (line 9) -* ASM_OUTPUT_DEBUG_LABEL: Label Output. (line 363) -* ASM_OUTPUT_DEF: Label Output. (line 412) -* ASM_OUTPUT_DEF_FROM_DECLS: Label Output. (line 419) -* ASM_OUTPUT_DWARF_DELTA: SDB and DWARF. (line 73) -* ASM_OUTPUT_DWARF_OFFSET: SDB and DWARF. (line 82) -* ASM_OUTPUT_DWARF_PCREL: SDB and DWARF. (line 88) -* ASM_OUTPUT_DWARF_TABLE_REF: SDB and DWARF. (line 93) -* ASM_OUTPUT_DWARF_VMS_DELTA: SDB and DWARF. (line 77) -* ASM_OUTPUT_EXTERNAL: Label Output. (line 292) -* ASM_OUTPUT_FDESC: Data Output. (line 59) -* ASM_OUTPUT_FUNCTION_LABEL: Label Output. (line 16) -* ASM_OUTPUT_INTERNAL_LABEL: Label Output. (line 27) -* ASM_OUTPUT_LABEL: Label Output. (line 8) -* ASM_OUTPUT_LABELREF: Label Output. (line 314) -* ASM_OUTPUT_LABEL_REF: Label Output. (line 336) -* ASM_OUTPUT_LOCAL: Uninitialized Data. (line 69) -* ASM_OUTPUT_MAX_SKIP_ALIGN: Alignment Output. (line 94) -* ASM_OUTPUT_MEASURED_SIZE: Label Output. (line 51) -* ASM_OUTPUT_OPCODE: Instruction Output. (line 35) -* ASM_OUTPUT_POOL_EPILOGUE: Data Output. (line 108) -* ASM_OUTPUT_POOL_PROLOGUE: Data Output. (line 72) -* ASM_OUTPUT_REG_POP: Instruction Output. (line 206) -* ASM_OUTPUT_REG_PUSH: Instruction Output. (line 201) -* ASM_OUTPUT_SIZE_DIRECTIVE: Label Output. (line 45) -* ASM_OUTPUT_SKIP: Alignment Output. (line 72) -* ASM_OUTPUT_SOURCE_FILENAME: File Framework. (line 83) -* ASM_OUTPUT_SPECIAL_POOL_ENTRY: Data Output. (line 83) -* ASM_OUTPUT_SYMBOL_REF: Label Output. (line 329) -* ASM_OUTPUT_TYPE_DIRECTIVE: Label Output. (line 98) -* ASM_OUTPUT_WEAKREF: Label Output. (line 224) -* ASM_OUTPUT_WEAK_ALIAS: Label Output. (line 438) -* ASM_PREFERRED_EH_DATA_FORMAT: Exception Handling. (line 66) -* ASM_SPEC: Driver. (line 73) -* ASM_STABD_OP: DBX Options. (line 34) -* ASM_STABN_OP: DBX Options. (line 41) -* ASM_STABS_OP: DBX Options. (line 28) -* ASM_WEAKEN_DECL: Label Output. (line 216) -* ASM_WEAKEN_LABEL: Label Output. (line 203) -* assembler format: File Framework. (line 6) -* assembler instructions in RTL: Assembler. (line 6) -* ASSEMBLER_DIALECT: Instruction Output. (line 172) -* assemble_name: Label Output. (line 8) -* assemble_name_raw: Label Output. (line 27) -* assigning attribute values to insns: Tagging Insns. (line 6) -* ASSUME_EXTENDED_UNWIND_CONTEXT: Frame Registers. (line 165) -* asterisk in template: Output Statement. (line 29) -* AS_NEEDS_DASH_FOR_PIPED_INPUT: Driver. (line 88) -* 'atan2M3' instruction pattern: Standard Names. (line 624) -* atomic: GTY Options. (line 270) -* 'atomic_addMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_add_fetchMODE' instruction pattern: Standard Names. - (line 1819) -* 'atomic_andMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_and_fetchMODE' instruction pattern: Standard Names. - (line 1819) -* 'atomic_compare_and_swapMODE' instruction pattern: Standard Names. - (line 1724) -* 'atomic_exchangeMODE' instruction pattern: Standard Names. (line 1776) -* 'atomic_fetch_addMODE' instruction pattern: Standard Names. - (line 1803) -* 'atomic_fetch_andMODE' instruction pattern: Standard Names. - (line 1803) -* 'atomic_fetch_nandMODE' instruction pattern: Standard Names. - (line 1803) -* 'atomic_fetch_orMODE' instruction pattern: Standard Names. (line 1803) -* 'atomic_fetch_subMODE' instruction pattern: Standard Names. - (line 1803) -* 'atomic_fetch_xorMODE' instruction pattern: Standard Names. - (line 1803) -* 'atomic_loadMODE' instruction pattern: Standard Names. (line 1755) -* 'atomic_nandMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_nand_fetchMODE' instruction pattern: Standard Names. - (line 1819) -* 'atomic_orMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_or_fetchMODE' instruction pattern: Standard Names. (line 1819) -* 'atomic_storeMODE' instruction pattern: Standard Names. (line 1765) -* 'atomic_subMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_sub_fetchMODE' instruction pattern: Standard Names. - (line 1819) -* 'atomic_test_and_set' instruction pattern: Standard Names. (line 1837) -* 'atomic_xorMODE' instruction pattern: Standard Names. (line 1788) -* 'atomic_xor_fetchMODE' instruction pattern: Standard Names. - (line 1819) -* attr: Expressions. (line 163) -* attr <1>: Tagging Insns. (line 54) -* attribute expressions: Expressions. (line 6) -* attribute specifications: Attr Example. (line 6) -* attribute specifications example: Attr Example. (line 6) -* attributes: Attributes. (line 6) -* attributes, defining: Defining Attributes. - (line 6) -* attributes, target-specific: Target Attributes. (line 6) -* ATTRIBUTE_ALIGNED_VALUE: Storage Layout. (line 172) -* attr_flag: Expressions. (line 138) -* autoincrement addressing, availability: Portability. (line 20) -* autoincrement/decrement addressing: Simple Constraints. (line 30) -* automata_option: Processor pipeline description. - (line 304) -* automaton based pipeline description: Processor pipeline description. - (line 6) -* automaton based pipeline description <1>: Processor pipeline description. - (line 49) -* automaton based scheduler: Processor pipeline description. - (line 6) -* AVOID_CCMODE_COPIES: Values in Registers. - (line 150) -* backslash: Output Template. (line 46) -* barrier: Insns. (line 176) -* 'barrier' and '/f': Flags. (line 107) -* 'barrier' and '/v': Flags. (line 44) -* BASE_REG_CLASS: Register Classes. (line 111) -* basic block: Basic Blocks. (line 6) -* Basic Statements: Basic Statements. (line 6) -* basic-block.h: Control Flow. (line 6) -* basic_block: Basic Blocks. (line 6) -* BASIC_BLOCK: Basic Blocks. (line 14) -* BB_HEAD, BB_END: Maintaining the CFG. - (line 76) -* bb_seq: GIMPLE sequences. (line 72) -* BIGGEST_ALIGNMENT: Storage Layout. (line 162) -* BIGGEST_FIELD_ALIGNMENT: Storage Layout. (line 183) -* BImode: Machine Modes. (line 22) -* BIND_EXPR: Unary and Binary Expressions. - (line 6) -* BINFO_TYPE: Classes. (line 6) -* bit-fields: Bit-Fields. (line 6) -* BITFIELD_NBYTES_LIMITED: Storage Layout. (line 393) -* BITS_BIG_ENDIAN: Storage Layout. (line 11) -* 'BITS_BIG_ENDIAN', effect on 'sign_extract': Bit-Fields. (line 8) -* BITS_PER_UNIT: Machine Modes. (line 345) -* BITS_PER_WORD: Storage Layout. (line 50) -* bitwise complement: Arithmetic. (line 155) -* bitwise exclusive-or: Arithmetic. (line 169) -* bitwise inclusive-or: Arithmetic. (line 164) -* bitwise logical-and: Arithmetic. (line 159) -* BIT_AND_EXPR: Unary and Binary Expressions. - (line 6) -* BIT_IOR_EXPR: Unary and Binary Expressions. - (line 6) -* BIT_NOT_EXPR: Unary and Binary Expressions. - (line 6) -* BIT_XOR_EXPR: Unary and Binary Expressions. - (line 6) -* BLKmode: Machine Modes. (line 185) -* 'BLKmode', and function return values: Calls. (line 23) -* 'blockage' instruction pattern: Standard Names. (line 1579) -* Blocks: Blocks. (line 6) -* BLOCK_FOR_INSN, gimple_bb: Maintaining the CFG. - (line 28) -* BLOCK_REG_PADDING: Register Arguments. (line 228) -* bool: Misc. (line 891) -* BOOLEAN_TYPE: Types. (line 6) -* BOOL_TYPE_SIZE: Type Layout. (line 43) -* branch prediction: Profile information. - (line 24) -* BRANCH_COST: Costs. (line 104) -* break_out_memory_refs: Addressing Modes. (line 134) -* BREAK_STMT: Statements for C++. (line 6) -* BSS_SECTION_ASM_OP: Sections. (line 67) -* bswap: Arithmetic. (line 247) -* 'bswapM2' instruction pattern: Standard Names. (line 534) -* 'btruncM2' instruction pattern: Standard Names. (line 642) -* build0: Macros and Functions. - (line 16) -* build1: Macros and Functions. - (line 17) -* build2: Macros and Functions. - (line 18) -* build3: Macros and Functions. - (line 19) -* build4: Macros and Functions. - (line 20) -* build5: Macros and Functions. - (line 21) -* build6: Macros and Functions. - (line 22) -* 'builtin_longjmp' instruction pattern: Standard Names. (line 1475) -* 'builtin_setjmp_receiver' instruction pattern: Standard Names. - (line 1465) -* 'builtin_setjmp_setup' instruction pattern: Standard Names. - (line 1454) -* BYTES_BIG_ENDIAN: Storage Layout. (line 23) -* 'BYTES_BIG_ENDIAN', effect on 'subreg': Regs and Memory. (line 219) -* byte_mode: Machine Modes. (line 358) -* C statements for assembler output: Output Statement. (line 6) -* call: Flags. (line 221) -* call <1>: Side Effects. (line 92) -* 'call' instruction pattern: Standard Names. (line 1120) -* 'call' usage: Calls. (line 10) -* 'call', in 'call_insn': Flags. (line 33) -* 'call', in 'mem': Flags. (line 81) -* call-clobbered register: Register Basics. (line 35) -* call-clobbered register <1>: Register Basics. (line 46) -* call-clobbered register <2>: Register Basics. (line 53) -* call-saved register: Register Basics. (line 35) -* call-saved register <1>: Register Basics. (line 46) -* call-saved register <2>: Register Basics. (line 53) -* call-used register: Register Basics. (line 35) -* call-used register <1>: Register Basics. (line 46) -* call-used register <2>: Register Basics. (line 53) -* CALLER_SAVE_PROFITABLE: Caller Saves. (line 10) -* calling conventions: Stack and Calling. (line 6) -* calling functions in RTL: Calls. (line 6) -* CALL_EXPR: Unary and Binary Expressions. - (line 6) -* call_insn: Insns. (line 95) -* 'call_insn' and '/c': Flags. (line 33) -* 'call_insn' and '/f': Flags. (line 107) -* 'call_insn' and '/i': Flags. (line 24) -* 'call_insn' and '/j': Flags. (line 161) -* 'call_insn' and '/s': Flags. (line 49) -* 'call_insn' and '/s' <1>: Flags. (line 148) -* 'call_insn' and '/u': Flags. (line 19) -* 'call_insn' and '/u' <1>: Flags. (line 39) -* 'call_insn' and '/u' or '/i': Flags. (line 29) -* 'call_insn' and '/v': Flags. (line 44) -* CALL_INSN_FUNCTION_USAGE: Insns. (line 101) -* 'call_pop' instruction pattern: Standard Names. (line 1148) -* CALL_POPS_ARGS: Stack Arguments. (line 132) -* CALL_REALLY_USED_REGISTERS: Register Basics. (line 45) -* CALL_USED_REGISTERS: Register Basics. (line 34) -* call_used_regs: Register Basics. (line 59) -* 'call_value' instruction pattern: Standard Names. (line 1140) -* 'call_value_pop' instruction pattern: Standard Names. (line 1148) -* canadian: Configure Terms. (line 6) -* CANNOT_CHANGE_MODE_CLASS: Register Classes. (line 533) -* 'CANNOT_CHANGE_MODE_CLASS' and subreg semantics: Regs and Memory. - (line 276) -* canonicalization of instructions: Insn Canonicalizations. - (line 6) -* 'canonicalize_funcptr_for_compare' instruction pattern: Standard Names. - (line 1309) -* can_create_pseudo_p: Standard Names. (line 75) -* can_fallthru: Basic Blocks. (line 67) -* 'casesi' instruction pattern: Standard Names. (line 1241) -* CASE_VECTOR_MODE: Misc. (line 26) -* CASE_VECTOR_PC_RELATIVE: Misc. (line 39) -* CASE_VECTOR_SHORTEN_MODE: Misc. (line 30) -* 'cbranchMODE4' instruction pattern: Standard Names. (line 1109) -* cc0: Regs and Memory. (line 303) -* cc0 <1>: CC0 Condition Codes. - (line 6) -* 'cc0', RTL sharing: Sharing. (line 27) -* cc0_rtx: Regs and Memory. (line 329) -* CC1PLUS_SPEC: Driver. (line 63) -* CC1_SPEC: Driver. (line 55) -* CCmode: Machine Modes. (line 178) -* CCmode <1>: MODE_CC Condition Codes. - (line 6) -* cc_status: CC0 Condition Codes. - (line 6) -* CC_STATUS_MDEP: CC0 Condition Codes. - (line 16) -* CC_STATUS_MDEP_INIT: CC0 Condition Codes. - (line 22) -* CDImode: Machine Modes. (line 204) -* 'ceilM2' instruction pattern: Standard Names. (line 658) -* CEIL_DIV_EXPR: Unary and Binary Expressions. - (line 6) -* CEIL_MOD_EXPR: Unary and Binary Expressions. - (line 6) -* CFA_FRAME_BASE_OFFSET: Frame Layout. (line 224) -* CFG verification: Maintaining the CFG. - (line 117) -* CFG, Control Flow Graph: Control Flow. (line 6) -* cfghooks.h: Maintaining the CFG. - (line 6) -* cgraph_finalize_function: Parsing pass. (line 51) -* chain_circular: GTY Options. (line 209) -* chain_next: GTY Options. (line 209) -* chain_prev: GTY Options. (line 209) -* change_address: Standard Names. (line 47) -* CHAR_TYPE_SIZE: Type Layout. (line 38) -* 'check_stack' instruction pattern: Standard Names. (line 1395) -* CHImode: Machine Modes. (line 204) -* CILK_PLUS: Cilk Plus Transformation. - (line 6) -* class definitions, register: Register Classes. (line 6) -* class preference constraints: Class Preferences. (line 6) -* class, scope: Classes. (line 6) -* classes of RTX codes: RTL Classes. (line 6) -* CLASSTYPE_DECLARED_CLASS: Classes. (line 6) -* CLASSTYPE_HAS_MUTABLE: Classes. (line 85) -* CLASSTYPE_NON_POD_P: Classes. (line 90) -* CLASS_MAX_NREGS: Register Classes. (line 521) -* CLASS_TYPE_P: Types for C++. (line 63) -* Cleanups: Cleanups. (line 6) -* CLEANUP_DECL: Statements for C++. (line 6) -* CLEANUP_EXPR: Statements for C++. (line 6) -* CLEANUP_POINT_EXPR: Unary and Binary Expressions. - (line 6) -* CLEANUP_STMT: Statements for C++. (line 6) -* CLEAR_BY_PIECES_P: Costs. (line 187) -* 'clear_cache' instruction pattern: Standard Names. (line 1900) -* CLEAR_INSN_CACHE: Trampolines. (line 98) -* CLEAR_RATIO: Costs. (line 175) -* clobber: Side Effects. (line 106) -* clrsb: Arithmetic. (line 216) -* clz: Arithmetic. (line 223) -* 'clzM2' instruction pattern: Standard Names. (line 723) -* CLZ_DEFINED_VALUE_AT_ZERO: Misc. (line 304) -* 'cmpmemM' instruction pattern: Standard Names. (line 863) -* 'cmpstrM' instruction pattern: Standard Names. (line 842) -* 'cmpstrnM' instruction pattern: Standard Names. (line 829) -* code generation RTL sequences: Expander Definitions. - (line 6) -* code iterators in '.md' files: Code Iterators. (line 6) -* codes, RTL expression: RTL Objects. (line 47) -* code_label: Insns. (line 125) -* CODE_LABEL: Basic Blocks. (line 50) -* 'code_label' and '/i': Flags. (line 59) -* 'code_label' and '/v': Flags. (line 44) -* CODE_LABEL_NUMBER: Insns. (line 125) -* COImode: Machine Modes. (line 204) -* COLLECT2_HOST_INITIALIZATION: Host Misc. (line 32) -* COLLECT_EXPORT_LIST: Misc. (line 791) -* COLLECT_SHARED_FINI_FUNC: Macros for Initialization. - (line 43) -* COLLECT_SHARED_INIT_FUNC: Macros for Initialization. - (line 32) -* commit_edge_insertions: Maintaining the CFG. - (line 105) -* compare: Arithmetic. (line 46) -* 'compare', canonicalization of: Insn Canonicalizations. - (line 36) -* comparison_operator: Machine-Independent Predicates. - (line 110) -* compiler passes and files: Passes. (line 6) -* complement, bitwise: Arithmetic. (line 155) -* COMPLEX_CST: Constant expressions. - (line 6) -* COMPLEX_EXPR: Unary and Binary Expressions. - (line 6) -* COMPLEX_TYPE: Types. (line 6) -* COMPONENT_REF: Storage References. (line 6) -* Compound Expressions: Compound Expressions. - (line 6) -* Compound Lvalues: Compound Lvalues. (line 6) -* COMPOUND_EXPR: Unary and Binary Expressions. - (line 6) -* COMPOUND_LITERAL_EXPR: Unary and Binary Expressions. - (line 6) -* COMPOUND_LITERAL_EXPR_DECL: Unary and Binary Expressions. - (line 377) -* COMPOUND_LITERAL_EXPR_DECL_EXPR: Unary and Binary Expressions. - (line 377) -* computed jump: Edges. (line 127) -* computing the length of an insn: Insn Lengths. (line 6) -* concat: Regs and Memory. (line 381) -* concatn: Regs and Memory. (line 387) -* cond: Comparisons. (line 90) -* 'cond' and attributes: Expressions. (line 37) -* condition code register: Regs and Memory. (line 303) -* condition code status: Condition Code. (line 6) -* condition codes: Comparisons. (line 20) -* conditional execution: Conditional Execution. - (line 6) -* Conditional Expressions: Conditional Expressions. - (line 6) -* conditions, in patterns: Patterns. (line 43) -* cond_exec: Side Effects. (line 253) -* COND_EXPR: Unary and Binary Expressions. - (line 6) -* configuration file: Filesystem. (line 6) -* configuration file <1>: Host Misc. (line 6) -* configure terms: Configure Terms. (line 6) -* CONJ_EXPR: Unary and Binary Expressions. - (line 6) -* const: Constants. (line 109) -* const0_rtx: Constants. (line 21) -* CONST0_RTX: Constants. (line 129) -* const1_rtx: Constants. (line 21) -* CONST1_RTX: Constants. (line 129) -* const2_rtx: Constants. (line 21) -* CONST2_RTX: Constants. (line 129) -* constant attributes: Constant Attributes. - (line 6) -* constant definitions: Constant Definitions. - (line 6) -* constants in constraints: Simple Constraints. (line 68) -* CONSTANT_ADDRESS_P: Addressing Modes. (line 28) -* CONSTANT_ALIGNMENT: Storage Layout. (line 236) -* CONSTANT_P: Addressing Modes. (line 35) -* CONSTANT_POOL_ADDRESS_P: Flags. (line 10) -* CONSTANT_POOL_BEFORE_FUNCTION: Data Output. (line 64) -* constm1_rtx: Constants. (line 21) -* constraint modifier characters: Modifiers. (line 6) -* constraint, matching: Simple Constraints. (line 140) -* constraints: Constraints. (line 6) -* constraints, defining: Define Constraints. (line 6) -* constraints, defining, obsolete method: Old Constraints. (line 6) -* constraints, machine specific: Machine Constraints. - (line 6) -* constraints, testing: C Constraint Interface. - (line 6) -* CONSTRAINT_LEN: Old Constraints. (line 11) -* constraint_num: C Constraint Interface. - (line 37) -* constraint_satisfied_p: C Constraint Interface. - (line 52) -* CONSTRUCTOR: Unary and Binary Expressions. - (line 6) -* constructors, automatic calls: Collect2. (line 15) -* constructors, output of: Initialization. (line 6) -* CONST_DECL: Declarations. (line 6) -* const_double: Constants. (line 37) -* 'const_double', RTL sharing: Sharing. (line 29) -* CONST_DOUBLE_LOW: Constants. (line 49) -* CONST_DOUBLE_OK_FOR_CONSTRAINT_P: Old Constraints. (line 66) -* CONST_DOUBLE_OK_FOR_LETTER_P: Old Constraints. (line 51) -* const_double_operand: Machine-Independent Predicates. - (line 20) -* const_fixed: Constants. (line 62) -* const_int: Constants. (line 8) -* 'const_int' and attribute tests: Expressions. (line 47) -* 'const_int' and attributes: Expressions. (line 10) -* 'const_int', RTL sharing: Sharing. (line 23) -* const_int_operand: Machine-Independent Predicates. - (line 15) -* CONST_OK_FOR_CONSTRAINT_P: Old Constraints. (line 46) -* CONST_OK_FOR_LETTER_P: Old Constraints. (line 38) -* const_string: Constants. (line 81) -* 'const_string' and attributes: Expressions. (line 20) -* const_true_rtx: Constants. (line 31) -* const_vector: Constants. (line 69) -* 'const_vector', RTL sharing: Sharing. (line 32) -* container: Containers. (line 6) -* CONTINUE_STMT: Statements for C++. (line 6) -* contributors: Contributors. (line 6) -* controlling register usage: Register Basics. (line 73) -* controlling the compilation driver: Driver. (line 6) -* conventions, run-time: Interface. (line 6) -* conversions: Conversions. (line 6) -* CONVERT_EXPR: Unary and Binary Expressions. - (line 6) -* 'copysignM3' instruction pattern: Standard Names. (line 704) -* copy_rtx: Addressing Modes. (line 189) -* copy_rtx_if_shared: Sharing. (line 64) -* 'cosM2' instruction pattern: Standard Names. (line 570) -* costs of instructions: Costs. (line 6) -* CPLUSPLUS_CPP_SPEC: Driver. (line 50) -* CPP_SPEC: Driver. (line 43) -* CP_INTEGRAL_TYPE: Types for C++. (line 55) -* cp_namespace_decls: Namespaces. (line 49) -* CP_TYPE_CONST_NON_VOLATILE_P: Types for C++. (line 33) -* CP_TYPE_CONST_P: Types for C++. (line 24) -* cp_type_quals: Types for C++. (line 6) -* cp_type_quals <1>: Types for C++. (line 16) -* CP_TYPE_RESTRICT_P: Types for C++. (line 30) -* CP_TYPE_VOLATILE_P: Types for C++. (line 27) -* CQImode: Machine Modes. (line 204) -* cross compilation and floating point: Floating Point. (line 6) -* crtl->args.pops_args: Function Entry. (line 104) -* crtl->args.pretend_args_size: Function Entry. (line 110) -* crtl->outgoing_args_size: Stack Arguments. (line 48) -* CRTSTUFF_T_CFLAGS: Target Fragment. (line 15) -* CRTSTUFF_T_CFLAGS_S: Target Fragment. (line 19) -* CRT_CALL_STATIC_FUNCTION: Sections. (line 120) -* CSImode: Machine Modes. (line 204) -* 'cstoreMODE4' instruction pattern: Standard Names. (line 1070) -* CTImode: Machine Modes. (line 204) -* 'ctrapMM4' instruction pattern: Standard Names. (line 1547) -* ctz: Arithmetic. (line 231) -* 'ctzM2' instruction pattern: Standard Names. (line 732) -* CTZ_DEFINED_VALUE_AT_ZERO: Misc. (line 305) -* CUMULATIVE_ARGS: Register Arguments. (line 126) -* current_function_is_leaf: Leaf Functions. (line 50) -* current_function_uses_only_leaf_regs: Leaf Functions. (line 50) -* current_insn_predicate: Conditional Execution. - (line 27) -* C_COMMON_OVERRIDE_OPTIONS: Run-time Target. (line 136) -* c_register_pragma: Misc. (line 407) -* c_register_pragma_with_expansion: Misc. (line 409) -* DAmode: Machine Modes. (line 154) -* data bypass: Processor pipeline description. - (line 105) -* data bypass <1>: Processor pipeline description. - (line 196) -* data dependence delays: Processor pipeline description. - (line 6) -* Data Dependency Analysis: Dependency analysis. - (line 6) -* data structures: Per-Function Data. (line 6) -* DATA_ABI_ALIGNMENT: Storage Layout. (line 228) -* DATA_ALIGNMENT: Storage Layout. (line 215) -* DATA_SECTION_ASM_OP: Sections. (line 52) -* DBR_OUTPUT_SEQEND: Instruction Output. (line 133) -* dbr_sequence_length: Instruction Output. (line 133) -* DBX_BLOCKS_FUNCTION_RELATIVE: DBX Options. (line 100) -* DBX_CONTIN_CHAR: DBX Options. (line 63) -* DBX_CONTIN_LENGTH: DBX Options. (line 53) -* DBX_DEBUGGING_INFO: DBX Options. (line 8) -* DBX_FUNCTION_FIRST: DBX Options. (line 94) -* DBX_LINES_FUNCTION_RELATIVE: DBX Options. (line 106) -* DBX_NO_XREFS: DBX Options. (line 47) -* DBX_OUTPUT_MAIN_SOURCE_FILENAME: File Names and DBX. (line 8) -* DBX_OUTPUT_MAIN_SOURCE_FILE_END: File Names and DBX. (line 33) -* DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END: File Names and DBX. - (line 41) -* DBX_OUTPUT_SOURCE_LINE: DBX Hooks. (line 8) -* DBX_REGISTER_NUMBER: All Debuggers. (line 8) -* DBX_REGPARM_STABS_CODE: DBX Options. (line 84) -* DBX_REGPARM_STABS_LETTER: DBX Options. (line 89) -* DBX_STATIC_CONST_VAR_CODE: DBX Options. (line 79) -* DBX_STATIC_STAB_DATA_SECTION: DBX Options. (line 70) -* DBX_TYPE_DECL_STABS_CODE: DBX Options. (line 75) -* DBX_USE_BINCL: DBX Options. (line 112) -* DCmode: Machine Modes. (line 199) -* DDmode: Machine Modes. (line 93) -* De Morgan's law: Insn Canonicalizations. - (line 51) -* dead_or_set_p: define_peephole. (line 65) -* DEBUGGER_ARG_OFFSET: All Debuggers. (line 36) -* DEBUGGER_AUTO_OFFSET: All Debuggers. (line 27) -* debug_expr: Debug Information. (line 22) -* DEBUG_EXPR_DECL: Declarations. (line 6) -* debug_insn: Insns. (line 236) -* DEBUG_SYMS_TEXT: DBX Options. (line 24) -* decimal float library: Decimal float library routines. - (line 6) -* declaration: Declarations. (line 6) -* declarations, RTL: RTL Declarations. (line 6) -* DECLARE_LIBRARY_RENAMES: Library Calls. (line 8) -* DECL_ALIGN: Declarations. (line 6) -* DECL_ANTICIPATED: Functions for C++. (line 42) -* DECL_ARGUMENTS: Function Basics. (line 36) -* DECL_ARRAY_DELETE_OPERATOR_P: Functions for C++. (line 158) -* DECL_ARTIFICIAL: Working with declarations. - (line 24) -* DECL_ARTIFICIAL <1>: Function Basics. (line 6) -* DECL_ARTIFICIAL <2>: Function Properties. - (line 47) -* DECL_ASSEMBLER_NAME: Function Basics. (line 6) -* DECL_ASSEMBLER_NAME <1>: Function Basics. (line 19) -* DECL_ATTRIBUTES: Attributes. (line 21) -* DECL_BASE_CONSTRUCTOR_P: Functions for C++. (line 88) -* DECL_COMPLETE_CONSTRUCTOR_P: Functions for C++. (line 84) -* DECL_COMPLETE_DESTRUCTOR_P: Functions for C++. (line 98) -* DECL_CONSTRUCTOR_P: Functions for C++. (line 77) -* DECL_CONST_MEMFUNC_P: Functions for C++. (line 71) -* DECL_CONTEXT: Namespaces. (line 31) -* DECL_CONV_FN_P: Functions for C++. (line 105) -* DECL_COPY_CONSTRUCTOR_P: Functions for C++. (line 92) -* DECL_DESTRUCTOR_P: Functions for C++. (line 95) -* DECL_EXTERNAL: Declarations. (line 6) -* DECL_EXTERNAL <1>: Function Properties. - (line 25) -* DECL_EXTERN_C_FUNCTION_P: Functions for C++. (line 46) -* DECL_FUNCTION_MEMBER_P: Functions for C++. (line 61) -* DECL_FUNCTION_SPECIFIC_OPTIMIZATION: Function Basics. (line 6) -* DECL_FUNCTION_SPECIFIC_OPTIMIZATION <1>: Function Properties. - (line 61) -* DECL_FUNCTION_SPECIFIC_TARGET: Function Basics. (line 6) -* DECL_FUNCTION_SPECIFIC_TARGET <1>: Function Properties. - (line 55) -* DECL_GLOBAL_CTOR_P: Functions for C++. (line 108) -* DECL_GLOBAL_DTOR_P: Functions for C++. (line 112) -* DECL_INITIAL: Declarations. (line 6) -* DECL_INITIAL <1>: Function Basics. (line 51) -* DECL_LINKONCE_P: Functions for C++. (line 50) -* DECL_LOCAL_FUNCTION_P: Functions for C++. (line 38) -* DECL_MAIN_P: Functions for C++. (line 34) -* DECL_NAME: Working with declarations. - (line 7) -* DECL_NAME <1>: Function Basics. (line 6) -* DECL_NAME <2>: Function Basics. (line 9) -* DECL_NAME <3>: Namespaces. (line 20) -* DECL_NAMESPACE_ALIAS: Namespaces. (line 35) -* DECL_NAMESPACE_STD_P: Namespaces. (line 45) -* DECL_NONCONVERTING_P: Functions for C++. (line 80) -* DECL_NONSTATIC_MEMBER_FUNCTION_P: Functions for C++. (line 68) -* DECL_NON_THUNK_FUNCTION_P: Functions for C++. (line 138) -* DECL_OVERLOADED_OPERATOR_P: Functions for C++. (line 102) -* DECL_PURE_P: Function Properties. - (line 40) -* DECL_RESULT: Function Basics. (line 41) -* DECL_SAVED_TREE: Function Basics. (line 44) -* DECL_SIZE: Declarations. (line 6) -* DECL_STATIC_FUNCTION_P: Functions for C++. (line 65) -* DECL_STMT: Statements for C++. (line 6) -* DECL_STMT_DECL: Statements for C++. (line 6) -* DECL_THUNK_P: Functions for C++. (line 116) -* DECL_VIRTUAL_P: Function Properties. - (line 44) -* DECL_VOLATILE_MEMFUNC_P: Functions for C++. (line 74) -* 'decrement_and_branch_until_zero' instruction pattern: Standard Names. - (line 1278) -* default: GTY Options. (line 82) -* default_file_start: File Framework. (line 8) -* DEFAULT_GDB_EXTENSIONS: DBX Options. (line 17) -* DEFAULT_PCC_STRUCT_RETURN: Aggregate Return. (line 34) -* DEFAULT_SIGNED_CHAR: Type Layout. (line 160) -* define_address_constraint: Define Constraints. (line 99) -* define_asm_attributes: Tagging Insns. (line 73) -* define_attr: Defining Attributes. - (line 6) -* define_automaton: Processor pipeline description. - (line 53) -* define_bypass: Processor pipeline description. - (line 196) -* define_code_attr: Code Iterators. (line 6) -* define_code_iterator: Code Iterators. (line 6) -* define_cond_exec: Conditional Execution. - (line 13) -* define_constants: Constant Definitions. - (line 6) -* define_constraint: Define Constraints. (line 45) -* define_cpu_unit: Processor pipeline description. - (line 68) -* define_c_enum: Constant Definitions. - (line 49) -* define_delay: Delay Slots. (line 25) -* define_enum: Constant Definitions. - (line 118) -* define_enum_attr: Defining Attributes. - (line 83) -* define_enum_attr <1>: Constant Definitions. - (line 136) -* define_expand: Expander Definitions. - (line 11) -* define_insn: Patterns. (line 6) -* 'define_insn' example: Example. (line 6) -* define_insn_and_split: Insn Splitting. (line 170) -* define_insn_reservation: Processor pipeline description. - (line 105) -* define_int_attr: Int Iterators. (line 6) -* define_int_iterator: Int Iterators. (line 6) -* define_memory_constraint: Define Constraints. (line 80) -* define_mode_attr: Substitutions. (line 6) -* define_mode_iterator: Defining Mode Iterators. - (line 6) -* define_peephole: define_peephole. (line 6) -* define_peephole2: define_peephole2. (line 6) -* define_predicate: Defining Predicates. - (line 6) -* define_query_cpu_unit: Processor pipeline description. - (line 90) -* define_register_constraint: Define Constraints. (line 26) -* define_reservation: Processor pipeline description. - (line 185) -* define_special_predicate: Defining Predicates. - (line 6) -* define_split: Insn Splitting. (line 32) -* define_subst: Define Subst. (line 6) -* define_subst <1>: Define Subst Example. - (line 6) -* define_subst <2>: Define Subst Pattern Matching. - (line 6) -* define_subst <3>: Define Subst Output Template. - (line 6) -* define_subst <4>: Define Subst. (line 14) -* define_subst <5>: Subst Iterators. (line 6) -* define_subst_attr: Subst Iterators. (line 6) -* define_subst_attr <1>: Subst Iterators. (line 26) -* defining attributes and their values: Defining Attributes. - (line 6) -* defining constraints: Define Constraints. (line 6) -* defining constraints, obsolete method: Old Constraints. (line 6) -* defining jump instruction patterns: Jump Patterns. (line 6) -* defining looping instruction patterns: Looping Patterns. (line 6) -* defining peephole optimizers: Peephole Definitions. - (line 6) -* defining predicates: Defining Predicates. - (line 6) -* defining RTL sequences for code generation: Expander Definitions. - (line 6) -* delay slots, defining: Delay Slots. (line 6) -* deletable: GTY Options. (line 158) -* DELETE_IF_ORDINARY: Filesystem. (line 79) -* Dependent Patterns: Dependent Patterns. (line 6) -* desc: GTY Options. (line 82) -* destructors, output of: Initialization. (line 6) -* deterministic finite state automaton: Processor pipeline description. - (line 6) -* deterministic finite state automaton <1>: Processor pipeline description. - (line 304) -* DFmode: Machine Modes. (line 76) -* DF_SIZE: Type Layout. (line 136) -* digits in constraint: Simple Constraints. (line 128) -* DImode: Machine Modes. (line 45) -* directory options .md: Including Patterns. (line 45) -* DIR_SEPARATOR: Filesystem. (line 18) -* DIR_SEPARATOR_2: Filesystem. (line 19) -* disabling certain registers: Register Basics. (line 73) -* dispatch table: Dispatch Tables. (line 8) -* div: Arithmetic. (line 117) -* 'div' and attributes: Expressions. (line 83) -* division: Arithmetic. (line 117) -* division <1>: Arithmetic. (line 131) -* division <2>: Arithmetic. (line 137) -* 'divM3' instruction pattern: Standard Names. (line 276) -* 'divmodM4' instruction pattern: Standard Names. (line 496) -* DOLLARS_IN_IDENTIFIERS: Misc. (line 452) -* 'doloop_begin' instruction pattern: Standard Names. (line 1300) -* 'doloop_end' instruction pattern: Standard Names. (line 1288) -* DONE: Expander Definitions. - (line 77) -* DONT_USE_BUILTIN_SETJMP: Exception Region Output. - (line 77) -* DOUBLE_TYPE_SIZE: Type Layout. (line 52) -* DO_BODY: Statements for C++. (line 6) -* DO_COND: Statements for C++. (line 6) -* DO_STMT: Statements for C++. (line 6) -* DQmode: Machine Modes. (line 118) -* driver: Driver. (line 6) -* DRIVER_SELF_SPECS: Driver. (line 8) -* dump examples: Dump examples. (line 6) -* dump setup: Dump setup. (line 6) -* dump types: Dump types. (line 6) -* dump verbosity: Dump output verbosity. - (line 6) -* DUMPFILE_FORMAT: Filesystem. (line 67) -* dump_basic_block: Dump types. (line 29) -* dump_generic_expr: Dump types. (line 31) -* dump_gimple_stmt: Dump types. (line 33) -* dump_printf: Dump types. (line 6) -* DWARF2_ASM_LINE_DEBUG_INFO: SDB and DWARF. (line 49) -* DWARF2_DEBUGGING_INFO: SDB and DWARF. (line 12) -* DWARF2_FRAME_INFO: SDB and DWARF. (line 29) -* DWARF2_FRAME_REG_OUT: Frame Registers. (line 151) -* DWARF2_UNWIND_INFO: Exception Region Output. - (line 38) -* DWARF_ALT_FRAME_RETURN_COLUMN: Frame Layout. (line 150) -* DWARF_CIE_DATA_ALIGNMENT: Exception Region Output. - (line 89) -* DWARF_FRAME_REGISTERS: Frame Registers. (line 109) -* DWARF_FRAME_REGNUM: Frame Registers. (line 143) -* DWARF_REG_TO_UNWIND_COLUMN: Frame Registers. (line 134) -* DWARF_ZERO_REG: Frame Layout. (line 161) -* DYNAMIC_CHAIN_ADDRESS: Frame Layout. (line 90) -* 'E' in constraint: Simple Constraints. (line 87) -* earlyclobber operand: Modifiers. (line 25) -* edge: Edges. (line 6) -* edge in the flow graph: Edges. (line 6) -* edge iterators: Edges. (line 15) -* edge splitting: Maintaining the CFG. - (line 105) -* EDGE_ABNORMAL: Edges. (line 127) -* EDGE_ABNORMAL, EDGE_ABNORMAL_CALL: Edges. (line 171) -* EDGE_ABNORMAL, EDGE_EH: Edges. (line 95) -* EDGE_ABNORMAL, EDGE_SIBCALL: Edges. (line 121) -* EDGE_FALLTHRU, force_nonfallthru: Edges. (line 85) -* 'EDOM', implicit usage: Library Calls. (line 59) -* EH_FRAME_IN_DATA_SECTION: Exception Region Output. - (line 19) -* EH_FRAME_SECTION_NAME: Exception Region Output. - (line 9) -* 'eh_return' instruction pattern: Standard Names. (line 1481) -* EH_RETURN_DATA_REGNO: Exception Handling. (line 6) -* EH_RETURN_HANDLER_RTX: Exception Handling. (line 38) -* EH_RETURN_STACKADJ_RTX: Exception Handling. (line 21) -* EH_TABLES_CAN_BE_READ_ONLY: Exception Region Output. - (line 28) -* EH_USES: Function Entry. (line 155) -* ei_edge: Edges. (line 43) -* ei_end_p: Edges. (line 27) -* ei_last: Edges. (line 23) -* ei_next: Edges. (line 35) -* ei_one_before_end_p: Edges. (line 31) -* ei_prev: Edges. (line 39) -* ei_safe_safe: Edges. (line 47) -* ei_start: Edges. (line 19) -* ELIMINABLE_REGS: Elimination. (line 46) -* ELSE_CLAUSE: Statements for C++. (line 6) -* Embedded C: Fixed-point fractional library routines. - (line 6) -* EMIT_MODE_SET: Mode Switching. (line 74) -* Empty Statements: Empty Statements. (line 6) -* EMPTY_CLASS_EXPR: Statements for C++. (line 6) -* EMPTY_FIELD_BOUNDARY: Storage Layout. (line 306) -* Emulated TLS: Emulated TLS. (line 6) -* enabled: Disable Insn Alternatives. - (line 6) -* ENDFILE_SPEC: Driver. (line 155) -* endianness: Portability. (line 20) -* ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR: Basic Blocks. (line 10) -* enum machine_mode: Machine Modes. (line 6) -* enum reg_class: Register Classes. (line 70) -* ENUMERAL_TYPE: Types. (line 6) -* enumerations: Constant Definitions. - (line 49) -* epilogue: Function Entry. (line 6) -* 'epilogue' instruction pattern: Standard Names. (line 1519) -* EPILOGUE_USES: Function Entry. (line 149) -* eq: Comparisons. (line 52) -* 'eq' and attributes: Expressions. (line 83) -* equal: Comparisons. (line 52) -* eq_attr: Expressions. (line 104) -* EQ_EXPR: Unary and Binary Expressions. - (line 6) -* 'errno', implicit usage: Library Calls. (line 71) -* EXACT_DIV_EXPR: Unary and Binary Expressions. - (line 6) -* examining SSA_NAMEs: SSA. (line 214) -* exception handling: Edges. (line 95) -* exception handling <1>: Exception Handling. (line 6) -* 'exception_receiver' instruction pattern: Standard Names. (line 1446) -* exclamation point: Multi-Alternative. (line 47) -* exclusion_set: Processor pipeline description. - (line 223) -* exclusive-or, bitwise: Arithmetic. (line 169) -* EXIT_EXPR: Unary and Binary Expressions. - (line 6) -* EXIT_IGNORE_STACK: Function Entry. (line 137) -* expander definitions: Expander Definitions. - (line 6) -* 'expM2' instruction pattern: Standard Names. (line 599) -* expression: Expression trees. (line 6) -* expression codes: RTL Objects. (line 47) -* EXPR_FILENAME: Working with declarations. - (line 14) -* EXPR_LINENO: Working with declarations. - (line 20) -* expr_list: Insns. (line 540) -* EXPR_STMT: Statements for C++. (line 6) -* EXPR_STMT_EXPR: Statements for C++. (line 6) -* 'extendMN2' instruction pattern: Standard Names. (line 921) -* extensible constraints: Simple Constraints. (line 171) -* EXTRA_ADDRESS_CONSTRAINT: Old Constraints. (line 120) -* EXTRA_CONSTRAINT: Old Constraints. (line 71) -* EXTRA_CONSTRAINT_STR: Old Constraints. (line 92) -* EXTRA_MEMORY_CONSTRAINT: Old Constraints. (line 97) -* EXTRA_SPECS: Driver. (line 182) -* 'extv' instruction pattern: Standard Names. (line 1012) -* 'extvM' instruction pattern: Standard Names. (line 957) -* 'extvmisalignM' instruction pattern: Standard Names. (line 967) -* 'extzv' instruction pattern: Standard Names. (line 1030) -* 'extzvM' instruction pattern: Standard Names. (line 981) -* 'extzvmisalignM' instruction pattern: Standard Names. (line 984) -* 'F' in constraint: Simple Constraints. (line 92) -* FAIL: Expander Definitions. - (line 83) -* fall-thru: Edges. (line 68) -* FATAL_EXIT_CODE: Host Misc. (line 6) -* FDL, GNU Free Documentation License: GNU Free Documentation License. - (line 6) -* features, optional, in system conventions: Run-time Target. - (line 59) -* ffs: Arithmetic. (line 211) -* 'ffsM2' instruction pattern: Standard Names. (line 713) -* FIELD_DECL: Declarations. (line 6) -* files and passes of the compiler: Passes. (line 6) -* files, generated: Files. (line 6) -* file_end_indicate_exec_stack: File Framework. (line 39) -* final_absence_set: Processor pipeline description. - (line 223) -* FINAL_PRESCAN_INSN: Instruction Output. (line 60) -* final_presence_set: Processor pipeline description. - (line 223) -* final_sequence: Instruction Output. (line 144) -* FIND_BASE_TERM: Addressing Modes. (line 117) -* finite state automaton minimization: Processor pipeline description. - (line 304) -* FINI_ARRAY_SECTION_ASM_OP: Sections. (line 113) -* FINI_SECTION_ASM_OP: Sections. (line 98) -* FIRST_PARM_OFFSET: Frame Layout. (line 65) -* 'FIRST_PARM_OFFSET' and virtual registers: Regs and Memory. - (line 65) -* FIRST_PSEUDO_REGISTER: Register Basics. (line 8) -* FIRST_STACK_REG: Stack Registers. (line 26) -* FIRST_VIRTUAL_REGISTER: Regs and Memory. (line 51) -* fix: Conversions. (line 66) -* fixed register: Register Basics. (line 15) -* fixed-point fractional library: Fixed-point fractional library routines. - (line 6) -* FIXED_CONVERT_EXPR: Unary and Binary Expressions. - (line 6) -* FIXED_CST: Constant expressions. - (line 6) -* FIXED_POINT_TYPE: Types. (line 6) -* FIXED_REGISTERS: Register Basics. (line 14) -* fixed_regs: Register Basics. (line 59) -* 'fixMN2' instruction pattern: Standard Names. (line 888) -* 'fixunsMN2' instruction pattern: Standard Names. (line 897) -* 'fixuns_truncMN2' instruction pattern: Standard Names. (line 912) -* 'fix_truncMN2' instruction pattern: Standard Names. (line 908) -* FIX_TRUNC_EXPR: Unary and Binary Expressions. - (line 6) -* flags in RTL expression: Flags. (line 6) -* float: Conversions. (line 58) -* floating point and cross compilation: Floating Point. (line 6) -* 'floatMN2' instruction pattern: Standard Names. (line 880) -* 'floatunsMN2' instruction pattern: Standard Names. (line 884) -* FLOAT_EXPR: Unary and Binary Expressions. - (line 6) -* float_extend: Conversions. (line 33) -* FLOAT_LIB_COMPARE_RETURNS_BOOL: Library Calls. (line 32) -* FLOAT_STORE_FLAG_VALUE: Misc. (line 286) -* float_truncate: Conversions. (line 53) -* FLOAT_TYPE_SIZE: Type Layout. (line 48) -* FLOAT_WORDS_BIG_ENDIAN: Storage Layout. (line 41) -* 'FLOAT_WORDS_BIG_ENDIAN', (lack of) effect on 'subreg': Regs and Memory. - (line 224) -* 'floorM2' instruction pattern: Standard Names. (line 634) -* FLOOR_DIV_EXPR: Unary and Binary Expressions. - (line 6) -* FLOOR_MOD_EXPR: Unary and Binary Expressions. - (line 6) -* flow-insensitive alias analysis: Alias analysis. (line 6) -* flow-sensitive alias analysis: Alias analysis. (line 6) -* fma: Arithmetic. (line 112) -* 'fmaM4' instruction pattern: Standard Names. (line 286) -* 'fmodM3' instruction pattern: Standard Names. (line 552) -* 'fmsM4' instruction pattern: Standard Names. (line 293) -* 'fnmaM4' instruction pattern: Standard Names. (line 299) -* 'fnmsM4' instruction pattern: Standard Names. (line 305) -* FORCE_CODE_SECTION_ALIGN: Sections. (line 144) -* force_reg: Standard Names. (line 36) -* FOR_BODY: Statements for C++. (line 6) -* FOR_COND: Statements for C++. (line 6) -* FOR_EXPR: Statements for C++. (line 6) -* FOR_INIT_STMT: Statements for C++. (line 6) -* FOR_STMT: Statements for C++. (line 6) -* fractional types: Fixed-point fractional library routines. - (line 6) -* 'fractMN2' instruction pattern: Standard Names. (line 930) -* 'fractunsMN2' instruction pattern: Standard Names. (line 945) -* fract_convert: Conversions. (line 82) -* FRACT_TYPE_SIZE: Type Layout. (line 67) -* frame layout: Frame Layout. (line 6) -* FRAME_ADDR_RTX: Frame Layout. (line 114) -* FRAME_GROWS_DOWNWARD: Frame Layout. (line 30) -* 'FRAME_GROWS_DOWNWARD' and virtual registers: Regs and Memory. - (line 69) -* FRAME_POINTER_CFA_OFFSET: Frame Layout. (line 210) -* frame_pointer_needed: Function Entry. (line 34) -* FRAME_POINTER_REGNUM: Frame Registers. (line 13) -* 'FRAME_POINTER_REGNUM' and virtual registers: Regs and Memory. - (line 74) -* frame_pointer_rtx: Frame Registers. (line 104) -* frame_related: Flags. (line 229) -* 'frame_related', in 'insn', 'call_insn', 'jump_insn', 'barrier', and 'set': Flags. - (line 107) -* 'frame_related', in 'mem': Flags. (line 85) -* 'frame_related', in 'reg': Flags. (line 94) -* 'frame_related', in 'symbol_ref': Flags. (line 165) -* frequency, count, BB_FREQ_BASE: Profile information. - (line 30) -* 'ftruncM2' instruction pattern: Standard Names. (line 903) -* function: Functions. (line 6) -* function <1>: Functions for C++. (line 6) -* function call conventions: Interface. (line 6) -* function entry and exit: Function Entry. (line 6) -* function entry point, alternate function entry point: Edges. - (line 180) -* function properties: Function Properties. - (line 6) -* function-call insns: Calls. (line 6) -* functions, leaf: Leaf Functions. (line 6) -* FUNCTION_ARG_OFFSET: Register Arguments. (line 196) -* FUNCTION_ARG_PADDING: Register Arguments. (line 203) -* FUNCTION_ARG_REGNO_P: Register Arguments. (line 251) -* FUNCTION_BOUNDARY: Storage Layout. (line 159) -* FUNCTION_DECL: Functions. (line 6) -* FUNCTION_DECL <1>: Functions for C++. (line 6) -* FUNCTION_MODE: Misc. (line 341) -* FUNCTION_PROFILER: Profiling. (line 8) -* FUNCTION_TYPE: Types. (line 6) -* FUNCTION_VALUE: Scalar Return. (line 52) -* FUNCTION_VALUE_REGNO_P: Scalar Return. (line 78) -* fundamental type: Types. (line 6) -* 'G' in constraint: Simple Constraints. (line 96) -* 'g' in constraint: Simple Constraints. (line 118) -* garbage collector, invocation: Invoking the garbage collector. - (line 6) -* garbage collector, troubleshooting: Troubleshooting. (line 6) -* GCC and portability: Portability. (line 6) -* GCC_DRIVER_HOST_INITIALIZATION: Host Misc. (line 36) -* gcov_type: Profile information. - (line 41) -* ge: Comparisons. (line 72) -* 'ge' and attributes: Expressions. (line 83) -* gencodes: RTL passes. (line 18) -* general_operand: Machine-Independent Predicates. - (line 104) -* GENERAL_REGS: Register Classes. (line 22) -* generated files: Files. (line 6) -* generating assembler output: Output Statement. (line 6) -* generating insns: RTL Template. (line 6) -* GENERIC: Parsing pass. (line 6) -* GENERIC <1>: GENERIC. (line 6) -* generic predicates: Machine-Independent Predicates. - (line 6) -* genflags: RTL passes. (line 18) -* GEN_ERRNO_RTX: Library Calls. (line 71) -* get_attr: Expressions. (line 99) -* get_attr_length: Insn Lengths. (line 46) -* GET_CLASS_NARROWEST_MODE: Machine Modes. (line 335) -* GET_CODE: RTL Objects. (line 47) -* get_frame_size: Elimination. (line 34) -* get_insns: Insns. (line 34) -* get_last_insn: Insns. (line 34) -* GET_MODE: Machine Modes. (line 282) -* GET_MODE_ALIGNMENT: Machine Modes. (line 322) -* GET_MODE_BITSIZE: Machine Modes. (line 306) -* GET_MODE_CLASS: Machine Modes. (line 296) -* GET_MODE_FBIT: Machine Modes. (line 313) -* GET_MODE_IBIT: Machine Modes. (line 309) -* GET_MODE_MASK: Machine Modes. (line 317) -* GET_MODE_NAME: Machine Modes. (line 293) -* GET_MODE_NUNITS: Machine Modes. (line 331) -* GET_MODE_SIZE: Machine Modes. (line 303) -* GET_MODE_UNIT_SIZE: Machine Modes. (line 325) -* GET_MODE_WIDER_MODE: Machine Modes. (line 299) -* GET_RTX_CLASS: RTL Classes. (line 6) -* GET_RTX_FORMAT: RTL Classes. (line 131) -* GET_RTX_LENGTH: RTL Classes. (line 128) -* 'get_thread_pointerMODE' instruction pattern: Standard Names. - (line 1869) -* geu: Comparisons. (line 72) -* 'geu' and attributes: Expressions. (line 83) -* GE_EXPR: Unary and Binary Expressions. - (line 6) -* GGC: Type Information. (line 6) -* ggc_collect: Invoking the garbage collector. - (line 6) -* GIMPLE: Parsing pass. (line 13) -* GIMPLE <1>: Gimplification pass. - (line 6) -* GIMPLE <2>: GIMPLE. (line 6) -* GIMPLE Exception Handling: GIMPLE Exception Handling. - (line 6) -* GIMPLE instruction set: GIMPLE instruction set. - (line 6) -* GIMPLE sequences: GIMPLE sequences. (line 6) -* GIMPLE statement iterators: Basic Blocks. (line 78) -* GIMPLE statement iterators <1>: Maintaining the CFG. - (line 33) -* gimple_addresses_taken: Manipulating GIMPLE statements. - (line 89) -* 'GIMPLE_ASM': 'GIMPLE_ASM'. (line 6) -* gimple_asm_clobber_op: 'GIMPLE_ASM'. (line 44) -* gimple_asm_input_op: 'GIMPLE_ASM'. (line 29) -* gimple_asm_nclobbers: 'GIMPLE_ASM'. (line 26) -* gimple_asm_ninputs: 'GIMPLE_ASM'. (line 20) -* gimple_asm_noutputs: 'GIMPLE_ASM'. (line 23) -* gimple_asm_output_op: 'GIMPLE_ASM'. (line 36) -* gimple_asm_set_clobber_op: 'GIMPLE_ASM'. (line 48) -* gimple_asm_set_input_op: 'GIMPLE_ASM'. (line 32) -* gimple_asm_set_output_op: 'GIMPLE_ASM'. (line 40) -* gimple_asm_set_volatile: 'GIMPLE_ASM'. (line 59) -* gimple_asm_string: 'GIMPLE_ASM'. (line 52) -* gimple_asm_volatile_p: 'GIMPLE_ASM'. (line 56) -* 'GIMPLE_ASSIGN': 'GIMPLE_ASSIGN'. (line 6) -* gimple_assign_cast_p: Logical Operators. (line 158) -* gimple_assign_cast_p <1>: 'GIMPLE_ASSIGN'. (line 92) -* gimple_assign_lhs: 'GIMPLE_ASSIGN'. (line 50) -* gimple_assign_lhs_ptr: 'GIMPLE_ASSIGN'. (line 53) -* gimple_assign_rhs1: 'GIMPLE_ASSIGN'. (line 56) -* gimple_assign_rhs1_ptr: 'GIMPLE_ASSIGN'. (line 59) -* gimple_assign_rhs2: 'GIMPLE_ASSIGN'. (line 63) -* gimple_assign_rhs2_ptr: 'GIMPLE_ASSIGN'. (line 66) -* gimple_assign_rhs3: 'GIMPLE_ASSIGN'. (line 70) -* gimple_assign_rhs3_ptr: 'GIMPLE_ASSIGN'. (line 73) -* gimple_assign_rhs_class: 'GIMPLE_ASSIGN'. (line 44) -* gimple_assign_rhs_code: 'GIMPLE_ASSIGN'. (line 40) -* gimple_assign_set_lhs: 'GIMPLE_ASSIGN'. (line 77) -* gimple_assign_set_rhs1: 'GIMPLE_ASSIGN'. (line 80) -* gimple_assign_set_rhs2: 'GIMPLE_ASSIGN'. (line 84) -* gimple_assign_set_rhs3: 'GIMPLE_ASSIGN'. (line 88) -* gimple_bb: Manipulating GIMPLE statements. - (line 17) -* 'GIMPLE_BIND': 'GIMPLE_BIND'. (line 6) -* gimple_bind_add_seq: 'GIMPLE_BIND'. (line 34) -* gimple_bind_add_stmt: 'GIMPLE_BIND'. (line 31) -* gimple_bind_append_vars: 'GIMPLE_BIND'. (line 18) -* gimple_bind_block: 'GIMPLE_BIND'. (line 39) -* gimple_bind_body: 'GIMPLE_BIND'. (line 22) -* gimple_bind_set_block: 'GIMPLE_BIND'. (line 44) -* gimple_bind_set_body: 'GIMPLE_BIND'. (line 26) -* gimple_bind_set_vars: 'GIMPLE_BIND'. (line 14) -* gimple_bind_vars: 'GIMPLE_BIND'. (line 11) -* gimple_block: Manipulating GIMPLE statements. - (line 20) -* gimple_build_asm: 'GIMPLE_ASM'. (line 6) -* gimple_build_asm_vec: 'GIMPLE_ASM'. (line 15) -* gimple_build_assign: 'GIMPLE_ASSIGN'. (line 6) -* gimple_build_assign_with_ops: 'GIMPLE_ASSIGN'. (line 28) -* gimple_build_bind: 'GIMPLE_BIND'. (line 6) -* gimple_build_call: 'GIMPLE_CALL'. (line 6) -* gimple_build_call_from_tree: 'GIMPLE_CALL'. (line 15) -* gimple_build_call_vec: 'GIMPLE_CALL'. (line 23) -* gimple_build_catch: 'GIMPLE_CATCH'. (line 6) -* gimple_build_cond: 'GIMPLE_COND'. (line 6) -* gimple_build_cond_from_tree: 'GIMPLE_COND'. (line 14) -* gimple_build_debug_bind: 'GIMPLE_DEBUG'. (line 6) -* gimple_build_eh_filter: 'GIMPLE_EH_FILTER'. (line 6) -* gimple_build_goto: 'GIMPLE_LABEL'. (line 17) -* gimple_build_label: 'GIMPLE_LABEL'. (line 6) -* gimple_build_nop: 'GIMPLE_NOP'. (line 6) -* gimple_build_omp_atomic_load: 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 6) -* gimple_build_omp_atomic_store: 'GIMPLE_OMP_ATOMIC_STORE'. - (line 6) -* gimple_build_omp_continue: 'GIMPLE_OMP_CONTINUE'. - (line 6) -* gimple_build_omp_critical: 'GIMPLE_OMP_CRITICAL'. - (line 6) -* gimple_build_omp_for: 'GIMPLE_OMP_FOR'. (line 6) -* gimple_build_omp_master: 'GIMPLE_OMP_MASTER'. - (line 6) -* gimple_build_omp_ordered: 'GIMPLE_OMP_ORDERED'. - (line 6) -* gimple_build_omp_parallel: 'GIMPLE_OMP_PARALLEL'. - (line 6) -* gimple_build_omp_return: 'GIMPLE_OMP_RETURN'. - (line 6) -* gimple_build_omp_section: 'GIMPLE_OMP_SECTION'. - (line 6) -* gimple_build_omp_sections: 'GIMPLE_OMP_SECTIONS'. - (line 6) -* gimple_build_omp_sections_switch: 'GIMPLE_OMP_SECTIONS'. - (line 13) -* gimple_build_omp_single: 'GIMPLE_OMP_SINGLE'. - (line 6) -* gimple_build_resx: 'GIMPLE_RESX'. (line 6) -* gimple_build_return: 'GIMPLE_RETURN'. (line 6) -* gimple_build_switch: 'GIMPLE_SWITCH'. (line 6) -* gimple_build_try: 'GIMPLE_TRY'. (line 6) -* gimple_build_wce: 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 6) -* 'GIMPLE_CALL': 'GIMPLE_CALL'. (line 6) -* gimple_call_arg: 'GIMPLE_CALL'. (line 65) -* gimple_call_arg_ptr: 'GIMPLE_CALL'. (line 69) -* gimple_call_cannot_inline_p: 'GIMPLE_CALL'. (line 90) -* gimple_call_chain: 'GIMPLE_CALL'. (line 56) -* gimple_call_copy_skip_args: 'GIMPLE_CALL'. (line 96) -* gimple_call_fn: 'GIMPLE_CALL'. (line 37) -* gimple_call_fndecl: 'GIMPLE_CALL'. (line 45) -* gimple_call_lhs: 'GIMPLE_CALL'. (line 28) -* gimple_call_lhs_ptr: 'GIMPLE_CALL'. (line 31) -* gimple_call_mark_uninlinable: 'GIMPLE_CALL'. (line 87) -* gimple_call_noreturn_p: 'GIMPLE_CALL'. (line 93) -* gimple_call_num_args: 'GIMPLE_CALL'. (line 62) -* gimple_call_return_type: 'GIMPLE_CALL'. (line 53) -* gimple_call_set_arg: 'GIMPLE_CALL'. (line 74) -* gimple_call_set_chain: 'GIMPLE_CALL'. (line 59) -* gimple_call_set_fn: 'GIMPLE_CALL'. (line 41) -* gimple_call_set_fndecl: 'GIMPLE_CALL'. (line 50) -* gimple_call_set_lhs: 'GIMPLE_CALL'. (line 34) -* gimple_call_set_tail: 'GIMPLE_CALL'. (line 79) -* gimple_call_tail_p: 'GIMPLE_CALL'. (line 84) -* 'GIMPLE_CATCH': 'GIMPLE_CATCH'. (line 6) -* gimple_catch_handler: 'GIMPLE_CATCH'. (line 19) -* gimple_catch_set_handler: 'GIMPLE_CATCH'. (line 26) -* gimple_catch_set_types: 'GIMPLE_CATCH'. (line 23) -* gimple_catch_types: 'GIMPLE_CATCH'. (line 12) -* gimple_catch_types_ptr: 'GIMPLE_CATCH'. (line 15) -* gimple_code: Manipulating GIMPLE statements. - (line 14) -* 'GIMPLE_COND': 'GIMPLE_COND'. (line 6) -* gimple_cond_code: 'GIMPLE_COND'. (line 20) -* gimple_cond_false_label: 'GIMPLE_COND'. (line 59) -* gimple_cond_lhs: 'GIMPLE_COND'. (line 29) -* gimple_cond_make_false: 'GIMPLE_COND'. (line 63) -* gimple_cond_make_true: 'GIMPLE_COND'. (line 66) -* gimple_cond_rhs: 'GIMPLE_COND'. (line 37) -* gimple_cond_set_code: 'GIMPLE_COND'. (line 24) -* gimple_cond_set_false_label: 'GIMPLE_COND'. (line 54) -* gimple_cond_set_lhs: 'GIMPLE_COND'. (line 33) -* gimple_cond_set_rhs: 'GIMPLE_COND'. (line 41) -* gimple_cond_set_true_label: 'GIMPLE_COND'. (line 49) -* gimple_cond_true_label: 'GIMPLE_COND'. (line 45) -* gimple_copy: Manipulating GIMPLE statements. - (line 146) -* 'GIMPLE_DEBUG': 'GIMPLE_DEBUG'. (line 6) -* 'GIMPLE_DEBUG_BIND': 'GIMPLE_DEBUG'. (line 6) -* gimple_debug_bind_get_value: 'GIMPLE_DEBUG'. (line 46) -* gimple_debug_bind_get_value_ptr: 'GIMPLE_DEBUG'. (line 50) -* gimple_debug_bind_get_var: 'GIMPLE_DEBUG'. (line 43) -* gimple_debug_bind_has_value_p: 'GIMPLE_DEBUG'. (line 68) -* gimple_debug_bind_p: Logical Operators. (line 162) -* gimple_debug_bind_reset_value: 'GIMPLE_DEBUG'. (line 64) -* gimple_debug_bind_set_value: 'GIMPLE_DEBUG'. (line 59) -* gimple_debug_bind_set_var: 'GIMPLE_DEBUG'. (line 55) -* gimple_def_ops: Manipulating GIMPLE statements. - (line 93) -* 'GIMPLE_EH_FILTER': 'GIMPLE_EH_FILTER'. (line 6) -* gimple_eh_filter_failure: 'GIMPLE_EH_FILTER'. (line 18) -* gimple_eh_filter_must_not_throw: 'GIMPLE_EH_FILTER'. (line 32) -* gimple_eh_filter_set_failure: 'GIMPLE_EH_FILTER'. (line 27) -* gimple_eh_filter_set_must_not_throw: 'GIMPLE_EH_FILTER'. (line 35) -* gimple_eh_filter_set_types: 'GIMPLE_EH_FILTER'. (line 22) -* gimple_eh_filter_types: 'GIMPLE_EH_FILTER'. (line 11) -* gimple_eh_filter_types_ptr: 'GIMPLE_EH_FILTER'. (line 14) -* gimple_expr_code: Manipulating GIMPLE statements. - (line 30) -* gimple_expr_type: Manipulating GIMPLE statements. - (line 23) -* gimple_goto_dest: 'GIMPLE_LABEL'. (line 20) -* gimple_goto_set_dest: 'GIMPLE_LABEL'. (line 23) -* gimple_has_mem_ops: Manipulating GIMPLE statements. - (line 71) -* gimple_has_ops: Manipulating GIMPLE statements. - (line 68) -* gimple_has_volatile_ops: Manipulating GIMPLE statements. - (line 133) -* 'GIMPLE_LABEL': 'GIMPLE_LABEL'. (line 6) -* gimple_label_label: 'GIMPLE_LABEL'. (line 10) -* gimple_label_set_label: 'GIMPLE_LABEL'. (line 13) -* gimple_loaded_syms: Manipulating GIMPLE statements. - (line 121) -* gimple_locus: Manipulating GIMPLE statements. - (line 41) -* gimple_locus_empty_p: Manipulating GIMPLE statements. - (line 47) -* gimple_modified_p: Manipulating GIMPLE statements. - (line 129) -* 'GIMPLE_NOP': 'GIMPLE_NOP'. (line 6) -* gimple_nop_p: 'GIMPLE_NOP'. (line 9) -* gimple_no_warning_p: Manipulating GIMPLE statements. - (line 50) -* gimple_num_ops: Logical Operators. (line 76) -* gimple_num_ops <1>: Manipulating GIMPLE statements. - (line 74) -* 'GIMPLE_OMP_ATOMIC_LOAD': 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 6) -* gimple_omp_atomic_load_lhs: 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 16) -* gimple_omp_atomic_load_rhs: 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 23) -* gimple_omp_atomic_load_set_lhs: 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 12) -* gimple_omp_atomic_load_set_rhs: 'GIMPLE_OMP_ATOMIC_LOAD'. - (line 19) -* 'GIMPLE_OMP_ATOMIC_STORE': 'GIMPLE_OMP_ATOMIC_STORE'. - (line 6) -* gimple_omp_atomic_store_set_val: 'GIMPLE_OMP_ATOMIC_STORE'. - (line 10) -* gimple_omp_atomic_store_val: 'GIMPLE_OMP_ATOMIC_STORE'. - (line 14) -* gimple_omp_body: 'GIMPLE_OMP_PARALLEL'. - (line 23) -* 'GIMPLE_OMP_CONTINUE': 'GIMPLE_OMP_CONTINUE'. - (line 6) -* gimple_omp_continue_control_def: 'GIMPLE_OMP_CONTINUE'. - (line 12) -* gimple_omp_continue_control_def_ptr: 'GIMPLE_OMP_CONTINUE'. - (line 16) -* gimple_omp_continue_control_use: 'GIMPLE_OMP_CONTINUE'. - (line 23) -* gimple_omp_continue_control_use_ptr: 'GIMPLE_OMP_CONTINUE'. - (line 27) -* gimple_omp_continue_set_control_def: 'GIMPLE_OMP_CONTINUE'. - (line 19) -* gimple_omp_continue_set_control_use: 'GIMPLE_OMP_CONTINUE'. - (line 30) -* 'GIMPLE_OMP_CRITICAL': 'GIMPLE_OMP_CRITICAL'. - (line 6) -* gimple_omp_critical_name: 'GIMPLE_OMP_CRITICAL'. - (line 12) -* gimple_omp_critical_name_ptr: 'GIMPLE_OMP_CRITICAL'. - (line 15) -* gimple_omp_critical_set_name: 'GIMPLE_OMP_CRITICAL'. - (line 19) -* 'GIMPLE_OMP_FOR': 'GIMPLE_OMP_FOR'. (line 6) -* gimple_omp_for_clauses: 'GIMPLE_OMP_FOR'. (line 19) -* gimple_omp_for_clauses_ptr: 'GIMPLE_OMP_FOR'. (line 22) -* gimple_omp_for_cond: 'GIMPLE_OMP_FOR'. (line 82) -* gimple_omp_for_final: 'GIMPLE_OMP_FOR'. (line 50) -* gimple_omp_for_final_ptr: 'GIMPLE_OMP_FOR'. (line 53) -* gimple_omp_for_incr: 'GIMPLE_OMP_FOR'. (line 60) -* gimple_omp_for_incr_ptr: 'GIMPLE_OMP_FOR'. (line 63) -* gimple_omp_for_index: 'GIMPLE_OMP_FOR'. (line 30) -* gimple_omp_for_index_ptr: 'GIMPLE_OMP_FOR'. (line 33) -* gimple_omp_for_initial: 'GIMPLE_OMP_FOR'. (line 40) -* gimple_omp_for_initial_ptr: 'GIMPLE_OMP_FOR'. (line 43) -* gimple_omp_for_pre_body: 'GIMPLE_OMP_FOR'. (line 69) -* gimple_omp_for_set_clauses: 'GIMPLE_OMP_FOR'. (line 25) -* gimple_omp_for_set_cond: 'GIMPLE_OMP_FOR'. (line 78) -* gimple_omp_for_set_final: 'GIMPLE_OMP_FOR'. (line 56) -* gimple_omp_for_set_incr: 'GIMPLE_OMP_FOR'. (line 66) -* gimple_omp_for_set_index: 'GIMPLE_OMP_FOR'. (line 36) -* gimple_omp_for_set_initial: 'GIMPLE_OMP_FOR'. (line 46) -* gimple_omp_for_set_pre_body: 'GIMPLE_OMP_FOR'. (line 73) -* 'GIMPLE_OMP_MASTER': 'GIMPLE_OMP_MASTER'. - (line 6) -* 'GIMPLE_OMP_ORDERED': 'GIMPLE_OMP_ORDERED'. - (line 6) -* 'GIMPLE_OMP_PARALLEL': 'GIMPLE_OMP_PARALLEL'. - (line 6) -* gimple_omp_parallel_child_fn: 'GIMPLE_OMP_PARALLEL'. - (line 41) -* gimple_omp_parallel_child_fn_ptr: 'GIMPLE_OMP_PARALLEL'. - (line 45) -* gimple_omp_parallel_clauses: 'GIMPLE_OMP_PARALLEL'. - (line 30) -* gimple_omp_parallel_clauses_ptr: 'GIMPLE_OMP_PARALLEL'. - (line 33) -* gimple_omp_parallel_combined_p: 'GIMPLE_OMP_PARALLEL'. - (line 15) -* gimple_omp_parallel_data_arg: 'GIMPLE_OMP_PARALLEL'. - (line 53) -* gimple_omp_parallel_data_arg_ptr: 'GIMPLE_OMP_PARALLEL'. - (line 57) -* gimple_omp_parallel_set_child_fn: 'GIMPLE_OMP_PARALLEL'. - (line 49) -* gimple_omp_parallel_set_clauses: 'GIMPLE_OMP_PARALLEL'. - (line 36) -* gimple_omp_parallel_set_combined_p: 'GIMPLE_OMP_PARALLEL'. - (line 19) -* gimple_omp_parallel_set_data_arg: 'GIMPLE_OMP_PARALLEL'. - (line 60) -* 'GIMPLE_OMP_RETURN': 'GIMPLE_OMP_RETURN'. - (line 6) -* gimple_omp_return_nowait_p: 'GIMPLE_OMP_RETURN'. - (line 13) -* gimple_omp_return_set_nowait: 'GIMPLE_OMP_RETURN'. - (line 10) -* 'GIMPLE_OMP_SECTION': 'GIMPLE_OMP_SECTION'. - (line 6) -* 'GIMPLE_OMP_SECTIONS': 'GIMPLE_OMP_SECTIONS'. - (line 6) -* gimple_omp_sections_clauses: 'GIMPLE_OMP_SECTIONS'. - (line 29) -* gimple_omp_sections_clauses_ptr: 'GIMPLE_OMP_SECTIONS'. - (line 32) -* gimple_omp_sections_control: 'GIMPLE_OMP_SECTIONS'. - (line 16) -* gimple_omp_sections_control_ptr: 'GIMPLE_OMP_SECTIONS'. - (line 20) -* gimple_omp_sections_set_clauses: 'GIMPLE_OMP_SECTIONS'. - (line 35) -* gimple_omp_sections_set_control: 'GIMPLE_OMP_SECTIONS'. - (line 24) -* gimple_omp_section_last_p: 'GIMPLE_OMP_SECTION'. - (line 11) -* gimple_omp_section_set_last: 'GIMPLE_OMP_SECTION'. - (line 15) -* gimple_omp_set_body: 'GIMPLE_OMP_PARALLEL'. - (line 26) -* 'GIMPLE_OMP_SINGLE': 'GIMPLE_OMP_SINGLE'. - (line 6) -* gimple_omp_single_clauses: 'GIMPLE_OMP_SINGLE'. - (line 13) -* gimple_omp_single_clauses_ptr: 'GIMPLE_OMP_SINGLE'. - (line 16) -* gimple_omp_single_set_clauses: 'GIMPLE_OMP_SINGLE'. - (line 19) -* gimple_op: Logical Operators. (line 79) -* gimple_op <1>: Manipulating GIMPLE statements. - (line 80) -* gimple_ops: Logical Operators. (line 82) -* gimple_ops <1>: Manipulating GIMPLE statements. - (line 77) -* gimple_op_ptr: Manipulating GIMPLE statements. - (line 83) -* 'GIMPLE_PHI': 'GIMPLE_PHI'. (line 6) -* gimple_phi_arg: 'GIMPLE_PHI'. (line 24) -* gimple_phi_arg <1>: SSA. (line 62) -* gimple_phi_arg_def: SSA. (line 68) -* gimple_phi_arg_edge: SSA. (line 65) -* gimple_phi_capacity: 'GIMPLE_PHI'. (line 6) -* gimple_phi_num_args: 'GIMPLE_PHI'. (line 10) -* gimple_phi_num_args <1>: SSA. (line 58) -* gimple_phi_result: 'GIMPLE_PHI'. (line 15) -* gimple_phi_result <1>: SSA. (line 55) -* gimple_phi_result_ptr: 'GIMPLE_PHI'. (line 18) -* gimple_phi_set_arg: 'GIMPLE_PHI'. (line 28) -* gimple_phi_set_result: 'GIMPLE_PHI'. (line 21) -* gimple_plf: Manipulating GIMPLE statements. - (line 64) -* 'GIMPLE_RESX': 'GIMPLE_RESX'. (line 6) -* gimple_resx_region: 'GIMPLE_RESX'. (line 12) -* gimple_resx_set_region: 'GIMPLE_RESX'. (line 15) -* 'GIMPLE_RETURN': 'GIMPLE_RETURN'. (line 6) -* gimple_return_retval: 'GIMPLE_RETURN'. (line 9) -* gimple_return_set_retval: 'GIMPLE_RETURN'. (line 12) -* gimple_seq_add_seq: GIMPLE sequences. (line 30) -* gimple_seq_add_stmt: GIMPLE sequences. (line 24) -* gimple_seq_alloc: GIMPLE sequences. (line 61) -* gimple_seq_copy: GIMPLE sequences. (line 65) -* gimple_seq_deep_copy: GIMPLE sequences. (line 36) -* gimple_seq_empty_p: GIMPLE sequences. (line 69) -* gimple_seq_first: GIMPLE sequences. (line 43) -* gimple_seq_init: GIMPLE sequences. (line 58) -* gimple_seq_last: GIMPLE sequences. (line 46) -* gimple_seq_reverse: GIMPLE sequences. (line 39) -* gimple_seq_set_first: GIMPLE sequences. (line 53) -* gimple_seq_set_last: GIMPLE sequences. (line 49) -* gimple_seq_singleton_p: GIMPLE sequences. (line 78) -* gimple_set_block: Manipulating GIMPLE statements. - (line 38) -* gimple_set_def_ops: Manipulating GIMPLE statements. - (line 96) -* gimple_set_has_volatile_ops: Manipulating GIMPLE statements. - (line 136) -* gimple_set_locus: Manipulating GIMPLE statements. - (line 44) -* gimple_set_op: Manipulating GIMPLE statements. - (line 86) -* gimple_set_plf: Manipulating GIMPLE statements. - (line 60) -* gimple_set_use_ops: Manipulating GIMPLE statements. - (line 103) -* gimple_set_vdef_ops: Manipulating GIMPLE statements. - (line 117) -* gimple_set_visited: Manipulating GIMPLE statements. - (line 53) -* gimple_set_vuse_ops: Manipulating GIMPLE statements. - (line 110) -* gimple_statement_base: Tuple representation. - (line 14) -* gimple_statement_with_ops: Tuple representation. - (line 96) -* gimple_stored_syms: Manipulating GIMPLE statements. - (line 125) -* 'GIMPLE_SWITCH': 'GIMPLE_SWITCH'. (line 6) -* gimple_switch_default_label: 'GIMPLE_SWITCH'. (line 38) -* gimple_switch_index: 'GIMPLE_SWITCH'. (line 23) -* gimple_switch_label: 'GIMPLE_SWITCH'. (line 29) -* gimple_switch_num_labels: 'GIMPLE_SWITCH'. (line 14) -* gimple_switch_set_default_label: 'GIMPLE_SWITCH'. (line 41) -* gimple_switch_set_index: 'GIMPLE_SWITCH'. (line 26) -* gimple_switch_set_label: 'GIMPLE_SWITCH'. (line 33) -* gimple_switch_set_num_labels: 'GIMPLE_SWITCH'. (line 18) -* 'GIMPLE_TRY': 'GIMPLE_TRY'. (line 6) -* gimple_try_catch_is_cleanup: 'GIMPLE_TRY'. (line 19) -* gimple_try_cleanup: 'GIMPLE_TRY'. (line 26) -* gimple_try_eval: 'GIMPLE_TRY'. (line 22) -* gimple_try_kind: 'GIMPLE_TRY'. (line 15) -* gimple_try_set_catch_is_cleanup: 'GIMPLE_TRY'. (line 30) -* gimple_try_set_cleanup: 'GIMPLE_TRY'. (line 39) -* gimple_try_set_eval: 'GIMPLE_TRY'. (line 34) -* gimple_use_ops: Manipulating GIMPLE statements. - (line 100) -* gimple_vdef_ops: Manipulating GIMPLE statements. - (line 114) -* gimple_visited_p: Manipulating GIMPLE statements. - (line 57) -* gimple_vuse_ops: Manipulating GIMPLE statements. - (line 107) -* gimple_wce_cleanup: 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 10) -* gimple_wce_cleanup_eh_only: 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 17) -* gimple_wce_set_cleanup: 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 13) -* gimple_wce_set_cleanup_eh_only: 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 20) -* 'GIMPLE_WITH_CLEANUP_EXPR': 'GIMPLE_WITH_CLEANUP_EXPR'. - (line 6) -* gimplification: Parsing pass. (line 13) -* gimplification <1>: Gimplification pass. - (line 6) -* gimplifier: Parsing pass. (line 13) -* gimplify_assign: 'GIMPLE_ASSIGN'. (line 17) -* gimplify_expr: Gimplification pass. - (line 18) -* gimplify_function_tree: Gimplification pass. - (line 18) -* GLOBAL_INIT_PRIORITY: Functions for C++. (line 141) -* global_regs: Register Basics. (line 59) -* 'GO_IF_LEGITIMATE_ADDRESS': Addressing Modes. (line 90) -* greater than: Comparisons. (line 60) -* greater than <1>: Comparisons. (line 64) -* greater than <2>: Comparisons. (line 72) -* gsi_after_labels: Sequence iterators. (line 74) -* gsi_bb: Sequence iterators. (line 82) -* gsi_commit_edge_inserts: Sequence iterators. (line 193) -* gsi_commit_edge_inserts <1>: Maintaining the CFG. - (line 105) -* gsi_commit_one_edge_insert: Sequence iterators. (line 188) -* gsi_end_p: Sequence iterators. (line 59) -* gsi_end_p <1>: Maintaining the CFG. - (line 48) -* gsi_for_stmt: Sequence iterators. (line 156) -* gsi_insert_after: Sequence iterators. (line 145) -* gsi_insert_after <1>: Maintaining the CFG. - (line 60) -* gsi_insert_before: Sequence iterators. (line 134) -* gsi_insert_before <1>: Maintaining the CFG. - (line 66) -* gsi_insert_on_edge: Sequence iterators. (line 173) -* gsi_insert_on_edge <1>: Maintaining the CFG. - (line 105) -* gsi_insert_on_edge_immediate: Sequence iterators. (line 183) -* gsi_insert_seq_after: Sequence iterators. (line 152) -* gsi_insert_seq_before: Sequence iterators. (line 141) -* gsi_insert_seq_on_edge: Sequence iterators. (line 177) -* gsi_last: Sequence iterators. (line 49) -* gsi_last <1>: Maintaining the CFG. - (line 44) -* gsi_last_bb: Sequence iterators. (line 55) -* gsi_link_after: Sequence iterators. (line 113) -* gsi_link_before: Sequence iterators. (line 103) -* gsi_link_seq_after: Sequence iterators. (line 108) -* gsi_link_seq_before: Sequence iterators. (line 97) -* gsi_move_after: Sequence iterators. (line 159) -* gsi_move_before: Sequence iterators. (line 164) -* gsi_move_to_bb_end: Sequence iterators. (line 169) -* gsi_next: Sequence iterators. (line 65) -* gsi_next <1>: Maintaining the CFG. - (line 52) -* gsi_one_before_end_p: Sequence iterators. (line 62) -* gsi_prev: Sequence iterators. (line 68) -* gsi_prev <1>: Maintaining the CFG. - (line 56) -* gsi_remove: Sequence iterators. (line 88) -* gsi_remove <1>: Maintaining the CFG. - (line 72) -* gsi_replace: Sequence iterators. (line 128) -* gsi_seq: Sequence iterators. (line 85) -* gsi_split_seq_after: Sequence iterators. (line 118) -* gsi_split_seq_before: Sequence iterators. (line 123) -* gsi_start: Sequence iterators. (line 39) -* gsi_start <1>: Maintaining the CFG. - (line 40) -* gsi_start_bb: Sequence iterators. (line 45) -* gsi_stmt: Sequence iterators. (line 71) -* gsi_stmt_ptr: Sequence iterators. (line 79) -* gt: Comparisons. (line 60) -* 'gt' and attributes: Expressions. (line 83) -* gtu: Comparisons. (line 64) -* 'gtu' and attributes: Expressions. (line 83) -* GTY: Type Information. (line 6) -* GT_EXPR: Unary and Binary Expressions. - (line 6) -* 'H' in constraint: Simple Constraints. (line 96) -* HAmode: Machine Modes. (line 146) -* HANDLER: Statements for C++. (line 6) -* HANDLER_BODY: Statements for C++. (line 6) -* HANDLER_PARMS: Statements for C++. (line 6) -* HANDLE_PRAGMA_PACK_WITH_EXPANSION: Misc. (line 442) -* hard registers: Regs and Memory. (line 9) -* HARD_FRAME_POINTER_IS_ARG_POINTER: Frame Registers. (line 57) -* HARD_FRAME_POINTER_IS_FRAME_POINTER: Frame Registers. (line 50) -* HARD_FRAME_POINTER_REGNUM: Frame Registers. (line 19) -* HARD_REGNO_CALLER_SAVE_MODE: Caller Saves. (line 19) -* HARD_REGNO_CALL_PART_CLOBBERED: Register Basics. (line 52) -* HARD_REGNO_MODE_OK: Values in Registers. - (line 57) -* HARD_REGNO_NREGS: Values in Registers. - (line 10) -* HARD_REGNO_NREGS_HAS_PADDING: Values in Registers. - (line 24) -* HARD_REGNO_NREGS_WITH_PADDING: Values in Registers. - (line 42) -* HARD_REGNO_RENAME_OK: Values in Registers. - (line 117) -* HAS_INIT_SECTION: Macros for Initialization. - (line 18) -* HAS_LONG_COND_BRANCH: Misc. (line 8) -* HAS_LONG_UNCOND_BRANCH: Misc. (line 17) -* HAVE_DOS_BASED_FILE_SYSTEM: Filesystem. (line 11) -* HAVE_POST_DECREMENT: Addressing Modes. (line 11) -* HAVE_POST_INCREMENT: Addressing Modes. (line 10) -* HAVE_POST_MODIFY_DISP: Addressing Modes. (line 17) -* HAVE_POST_MODIFY_REG: Addressing Modes. (line 23) -* HAVE_PRE_DECREMENT: Addressing Modes. (line 9) -* HAVE_PRE_INCREMENT: Addressing Modes. (line 8) -* HAVE_PRE_MODIFY_DISP: Addressing Modes. (line 16) -* HAVE_PRE_MODIFY_REG: Addressing Modes. (line 22) -* HCmode: Machine Modes. (line 199) -* HFmode: Machine Modes. (line 61) -* high: Constants. (line 119) -* HImode: Machine Modes. (line 29) -* 'HImode', in 'insn': Insns. (line 268) -* HONOR_REG_ALLOC_ORDER: Allocation Order. (line 36) -* host configuration: Host Config. (line 6) -* host functions: Host Common. (line 6) -* host hooks: Host Common. (line 6) -* host makefile fragment: Host Fragment. (line 6) -* HOST_BIT_BUCKET: Filesystem. (line 51) -* HOST_EXECUTABLE_SUFFIX: Filesystem. (line 45) -* HOST_HOOKS_EXTRA_SIGNALS: Host Common. (line 11) -* HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY: Host Common. (line 43) -* HOST_HOOKS_GT_PCH_GET_ADDRESS: Host Common. (line 15) -* HOST_HOOKS_GT_PCH_USE_ADDRESS: Host Common. (line 24) -* HOST_LACKS_INODE_NUMBERS: Filesystem. (line 89) -* HOST_LONG_FORMAT: Host Misc. (line 45) -* HOST_LONG_LONG_FORMAT: Host Misc. (line 41) -* HOST_OBJECT_SUFFIX: Filesystem. (line 40) -* HOST_PTR_PRINTF: Host Misc. (line 49) -* HOT_TEXT_SECTION_NAME: Sections. (line 42) -* HQmode: Machine Modes. (line 110) -* 'i' in constraint: Simple Constraints. (line 68) -* 'I' in constraint: Simple Constraints. (line 79) -* identifier: Identifiers. (line 6) -* IDENTIFIER_LENGTH: Identifiers. (line 22) -* IDENTIFIER_NODE: Identifiers. (line 6) -* IDENTIFIER_OPNAME_P: Identifiers. (line 27) -* IDENTIFIER_POINTER: Identifiers. (line 17) -* IDENTIFIER_TYPENAME_P: Identifiers. (line 33) -* IEEE 754-2008: Decimal float library routines. - (line 6) -* IFCVT_MACHDEP_INIT: Misc. (line 567) -* IFCVT_MODIFY_CANCEL: Misc. (line 561) -* IFCVT_MODIFY_FINAL: Misc. (line 555) -* IFCVT_MODIFY_INSN: Misc. (line 549) -* IFCVT_MODIFY_MULTIPLE_TESTS: Misc. (line 541) -* IFCVT_MODIFY_TESTS: Misc. (line 531) -* IF_COND: Statements for C++. (line 6) -* if_marked: GTY Options. (line 165) -* IF_STMT: Statements for C++. (line 6) -* if_then_else: Comparisons. (line 80) -* 'if_then_else' and attributes: Expressions. (line 32) -* 'if_then_else' usage: Side Effects. (line 56) -* IMAGPART_EXPR: Unary and Binary Expressions. - (line 6) -* Immediate Uses: SSA Operands. (line 258) -* immediate_operand: Machine-Independent Predicates. - (line 10) -* IMMEDIATE_PREFIX: Instruction Output. (line 153) -* include: Including Patterns. (line 6) -* INCLUDE_DEFAULTS: Driver. (line 327) -* inclusive-or, bitwise: Arithmetic. (line 164) -* INCOMING_FRAME_SP_OFFSET: Frame Layout. (line 181) -* INCOMING_REGNO: Register Basics. (line 87) -* INCOMING_RETURN_ADDR_RTX: Frame Layout. (line 137) -* INCOMING_STACK_BOUNDARY: Storage Layout. (line 154) -* INDEX_REG_CLASS: Register Classes. (line 140) -* 'indirect_jump' instruction pattern: Standard Names. (line 1237) -* indirect_operand: Machine-Independent Predicates. - (line 70) -* INDIRECT_REF: Storage References. (line 6) -* initialization routines: Initialization. (line 6) -* INITIAL_ELIMINATION_OFFSET: Elimination. (line 84) -* INITIAL_FRAME_ADDRESS_RTX: Frame Layout. (line 81) -* INITIAL_FRAME_POINTER_OFFSET: Elimination. (line 34) -* INIT_ARRAY_SECTION_ASM_OP: Sections. (line 106) -* INIT_CUMULATIVE_ARGS: Register Arguments. (line 147) -* INIT_CUMULATIVE_INCOMING_ARGS: Register Arguments. (line 175) -* INIT_CUMULATIVE_LIBCALL_ARGS: Register Arguments. (line 169) -* INIT_ENVIRONMENT: Driver. (line 305) -* INIT_EXPANDERS: Per-Function Data. (line 36) -* INIT_EXPR: Unary and Binary Expressions. - (line 6) -* init_machine_status: Per-Function Data. (line 42) -* init_one_libfunc: Library Calls. (line 15) -* INIT_SECTION_ASM_OP: Sections. (line 90) -* INIT_SECTION_ASM_OP <1>: Macros for Initialization. - (line 9) -* inlining: Target Attributes. (line 95) -* insert_insn_on_edge: Maintaining the CFG. - (line 105) -* insn: Insns. (line 63) -* 'insn' and '/f': Flags. (line 107) -* 'insn' and '/j': Flags. (line 157) -* 'insn' and '/s': Flags. (line 49) -* 'insn' and '/s' <1>: Flags. (line 148) -* 'insn' and '/u': Flags. (line 39) -* 'insn' and '/v': Flags. (line 44) -* insn attributes: Insn Attributes. (line 6) -* insn canonicalization: Insn Canonicalizations. - (line 6) -* insn includes: Including Patterns. (line 6) -* insn lengths, computing: Insn Lengths. (line 6) -* insn notes, notes: Basic Blocks. (line 52) -* insn splitting: Insn Splitting. (line 6) -* insn-attr.h: Defining Attributes. - (line 34) -* insns: Insns. (line 6) -* insns, generating: RTL Template. (line 6) -* insns, recognizing: RTL Template. (line 6) -* INSN_ANNULLED_BRANCH_P: Flags. (line 39) -* INSN_CODE: Insns. (line 295) -* INSN_DELETED_P: Flags. (line 44) -* INSN_FROM_TARGET_P: Flags. (line 49) -* insn_list: Insns. (line 540) -* INSN_REFERENCES_ARE_DELAYED: Misc. (line 469) -* INSN_SETS_ARE_DELAYED: Misc. (line 458) -* INSN_UID: Insns. (line 23) -* INSN_VAR_LOCATION: Insns. (line 236) -* instruction attributes: Insn Attributes. (line 6) -* instruction latency time: Processor pipeline description. - (line 6) -* instruction latency time <1>: Processor pipeline description. - (line 105) -* instruction latency time <2>: Processor pipeline description. - (line 196) -* instruction patterns: Patterns. (line 6) -* instruction splitting: Insn Splitting. (line 6) -* 'insv' instruction pattern: Standard Names. (line 1036) -* 'insvM' instruction pattern: Standard Names. (line 988) -* 'insvmisalignM' instruction pattern: Standard Names. (line 998) -* int iterators in '.md' files: Int Iterators. (line 6) -* INT16_TYPE: Type Layout. (line 253) -* INT32_TYPE: Type Layout. (line 254) -* INT64_TYPE: Type Layout. (line 255) -* INT8_TYPE: Type Layout. (line 252) -* INTEGER_CST: Constant expressions. - (line 6) -* INTEGER_TYPE: Types. (line 6) -* Interdependence of Patterns: Dependent Patterns. (line 6) -* interfacing to GCC output: Interface. (line 6) -* interlock delays: Processor pipeline description. - (line 6) -* intermediate representation lowering: Parsing pass. (line 13) -* INTMAX_TYPE: Type Layout. (line 229) -* INTPTR_TYPE: Type Layout. (line 276) -* introduction: Top. (line 6) -* INT_FAST16_TYPE: Type Layout. (line 269) -* INT_FAST32_TYPE: Type Layout. (line 270) -* INT_FAST64_TYPE: Type Layout. (line 271) -* INT_FAST8_TYPE: Type Layout. (line 268) -* INT_LEAST16_TYPE: Type Layout. (line 261) -* INT_LEAST32_TYPE: Type Layout. (line 262) -* INT_LEAST64_TYPE: Type Layout. (line 263) -* INT_LEAST8_TYPE: Type Layout. (line 260) -* INT_TYPE_SIZE: Type Layout. (line 11) -* INVOKE__main: Macros for Initialization. - (line 50) -* in_struct: Flags. (line 245) -* 'in_struct', in 'code_label' and 'note': Flags. (line 59) -* 'in_struct', in 'insn' and 'jump_insn' and 'call_insn': Flags. - (line 49) -* 'in_struct', in 'insn', 'call_insn', 'jump_insn' and 'jump_table_data': Flags. - (line 148) -* 'in_struct', in 'subreg': Flags. (line 187) -* ior: Arithmetic. (line 164) -* 'ior' and attributes: Expressions. (line 50) -* 'ior', canonicalization of: Insn Canonicalizations. - (line 51) -* 'iorM3' instruction pattern: Standard Names. (line 276) -* IRA_HARD_REGNO_ADD_COST_MULTIPLIER: Allocation Order. (line 44) -* IS_ASM_LOGICAL_LINE_SEPARATOR: Data Output. (line 119) -* is_gimple_addressable: Logical Operators. (line 113) -* is_gimple_asm_val: Logical Operators. (line 117) -* is_gimple_assign: Logical Operators. (line 149) -* is_gimple_call: Logical Operators. (line 152) -* is_gimple_call_addr: Logical Operators. (line 120) -* is_gimple_constant: Logical Operators. (line 128) -* is_gimple_debug: Logical Operators. (line 155) -* is_gimple_ip_invariant: Logical Operators. (line 137) -* is_gimple_ip_invariant_address: Logical Operators. (line 142) -* is_gimple_mem_ref_addr: Logical Operators. (line 124) -* is_gimple_min_invariant: Logical Operators. (line 131) -* is_gimple_omp: Logical Operators. (line 166) -* is_gimple_val: Logical Operators. (line 107) -* iterators in '.md' files: Iterators. (line 6) -* IV analysis on GIMPLE: Scalar evolutions. (line 6) -* IV analysis on RTL: loop-iv. (line 6) -* JMP_BUF_SIZE: Exception Region Output. - (line 82) -* jump: Flags. (line 286) -* 'jump' instruction pattern: Standard Names. (line 1115) -* jump instruction patterns: Jump Patterns. (line 6) -* jump instructions and 'set': Side Effects. (line 56) -* 'jump', in 'call_insn': Flags. (line 161) -* 'jump', in 'insn': Flags. (line 157) -* 'jump', in 'mem': Flags. (line 70) -* Jumps: Jumps. (line 6) -* JUMP_ALIGN: Alignment Output. (line 8) -* jump_insn: Insns. (line 73) -* 'jump_insn' and '/f': Flags. (line 107) -* 'jump_insn' and '/s': Flags. (line 49) -* 'jump_insn' and '/s' <1>: Flags. (line 148) -* 'jump_insn' and '/u': Flags. (line 39) -* 'jump_insn' and '/v': Flags. (line 44) -* JUMP_LABEL: Insns. (line 80) -* JUMP_TABLES_IN_TEXT_SECTION: Sections. (line 150) -* jump_table_data: Insns. (line 166) -* 'jump_table_data' and '/s': Flags. (line 148) -* 'jump_table_data' and '/v': Flags. (line 44) -* LABEL_ALIGN: Alignment Output. (line 57) -* LABEL_ALIGN_AFTER_BARRIER: Alignment Output. (line 26) -* LABEL_ALTERNATE_NAME: Edges. (line 180) -* LABEL_ALT_ENTRY_P: Insns. (line 146) -* LABEL_DECL: Declarations. (line 6) -* LABEL_KIND: Insns. (line 146) -* LABEL_NUSES: Insns. (line 142) -* LABEL_PRESERVE_P: Flags. (line 59) -* label_ref: Constants. (line 96) -* 'label_ref' and '/v': Flags. (line 65) -* 'label_ref', RTL sharing: Sharing. (line 35) -* LABEL_REF_NONLOCAL_P: Flags. (line 65) -* language-dependent trees: Language-dependent trees. - (line 6) -* language-independent intermediate representation: Parsing pass. - (line 13) -* lang_hooks.gimplify_expr: Gimplification pass. - (line 18) -* lang_hooks.parse_file: Parsing pass. (line 6) -* large return values: Aggregate Return. (line 6) -* LARGEST_EXPONENT_IS_NORMAL: Storage Layout. (line 483) -* LAST_STACK_REG: Stack Registers. (line 30) -* LAST_VIRTUAL_REGISTER: Regs and Memory. (line 51) -* 'lceilMN2': Standard Names. (line 699) -* LCSSA: LCSSA. (line 6) -* LDD_SUFFIX: Macros for Initialization. - (line 121) -* LD_FINI_SWITCH: Macros for Initialization. - (line 28) -* LD_INIT_SWITCH: Macros for Initialization. - (line 24) -* le: Comparisons. (line 76) -* 'le' and attributes: Expressions. (line 83) -* leaf functions: Leaf Functions. (line 6) -* leaf_function_p: Standard Names. (line 1199) -* LEAF_REGISTERS: Leaf Functions. (line 23) -* LEAF_REG_REMAP: Leaf Functions. (line 37) -* left rotate: Arithmetic. (line 196) -* left shift: Arithmetic. (line 174) -* LEGITIMATE_PIC_OPERAND_P: PIC. (line 31) -* LEGITIMIZE_RELOAD_ADDRESS: Addressing Modes. (line 150) -* length: GTY Options. (line 47) -* less than: Comparisons. (line 68) -* less than or equal: Comparisons. (line 76) -* leu: Comparisons. (line 76) -* 'leu' and attributes: Expressions. (line 83) -* LE_EXPR: Unary and Binary Expressions. - (line 6) -* 'lfloorMN2': Standard Names. (line 694) -* LIB2FUNCS_EXTRA: Target Fragment. (line 11) -* LIBCALL_VALUE: Scalar Return. (line 56) -* 'libgcc.a': Library Calls. (line 6) -* LIBGCC2_CFLAGS: Target Fragment. (line 8) -* LIBGCC2_GNU_PREFIX: Type Layout. (line 127) -* LIBGCC2_HAS_DF_MODE: Type Layout. (line 108) -* LIBGCC2_HAS_TF_MODE: Type Layout. (line 121) -* LIBGCC2_HAS_XF_MODE: Type Layout. (line 115) -* LIBGCC2_LONG_DOUBLE_TYPE_SIZE: Type Layout. (line 102) -* LIBGCC2_UNWIND_ATTRIBUTE: Misc. (line 996) -* LIBGCC_SPEC: Driver. (line 115) -* library subroutine names: Library Calls. (line 6) -* LIBRARY_PATH_ENV: Misc. (line 509) -* LIB_SPEC: Driver. (line 107) -* LIMIT_RELOAD_CLASS: Register Classes. (line 296) -* LINK_COMMAND_SPEC: Driver. (line 236) -* LINK_EH_SPEC: Driver. (line 142) -* LINK_GCC_C_SEQUENCE_SPEC: Driver. (line 232) -* LINK_LIBGCC_SPECIAL_1: Driver. (line 227) -* LINK_SPEC: Driver. (line 100) -* list: Containers. (line 6) -* Liveness representation: Liveness information. - (line 6) -* load address instruction: Simple Constraints. (line 162) -* LOAD_EXTEND_OP: Misc. (line 59) -* 'load_multiple' instruction pattern: Standard Names. (line 136) -* Local Register Allocator (LRA): RTL passes. (line 187) -* LOCAL_ALIGNMENT: Storage Layout. (line 249) -* LOCAL_CLASS_P: Classes. (line 73) -* LOCAL_DECL_ALIGNMENT: Storage Layout. (line 286) -* LOCAL_INCLUDE_DIR: Driver. (line 312) -* LOCAL_LABEL_PREFIX: Instruction Output. (line 151) -* LOCAL_REGNO: Register Basics. (line 101) -* Logical Operators: Logical Operators. (line 6) -* logical-and, bitwise: Arithmetic. (line 159) -* LOGICAL_OP_NON_SHORT_CIRCUIT: Costs. (line 264) -* 'logM2' instruction pattern: Standard Names. (line 607) -* LOG_LINKS: Insns. (line 314) -* 'longjmp' and automatic variables: Interface. (line 52) -* LONG_ACCUM_TYPE_SIZE: Type Layout. (line 92) -* LONG_DOUBLE_TYPE_SIZE: Type Layout. (line 57) -* LONG_FRACT_TYPE_SIZE: Type Layout. (line 72) -* LONG_LONG_ACCUM_TYPE_SIZE: Type Layout. (line 97) -* LONG_LONG_FRACT_TYPE_SIZE: Type Layout. (line 77) -* LONG_LONG_TYPE_SIZE: Type Layout. (line 32) -* LONG_TYPE_SIZE: Type Layout. (line 21) -* Loop analysis: Loop representation. - (line 6) -* Loop manipulation: Loop manipulation. (line 6) -* Loop querying: Loop querying. (line 6) -* Loop representation: Loop representation. - (line 6) -* Loop-closed SSA form: LCSSA. (line 6) -* looping instruction patterns: Looping Patterns. (line 6) -* LOOP_ALIGN: Alignment Output. (line 40) -* LOOP_EXPR: Unary and Binary Expressions. - (line 6) -* lowering, language-dependent intermediate representation: Parsing pass. - (line 13) -* lo_sum: Arithmetic. (line 25) -* 'lrintMN2': Standard Names. (line 684) -* 'lroundMN2': Standard Names. (line 689) -* lshiftrt: Arithmetic. (line 191) -* 'lshiftrt' and attributes: Expressions. (line 83) -* LSHIFT_EXPR: Unary and Binary Expressions. - (line 6) -* 'lshrM3' instruction pattern: Standard Names. (line 526) -* lt: Comparisons. (line 68) -* 'lt' and attributes: Expressions. (line 83) -* LTGT_EXPR: Unary and Binary Expressions. - (line 6) -* lto: LTO. (line 6) -* ltrans: LTO. (line 6) -* ltu: Comparisons. (line 68) -* LT_EXPR: Unary and Binary Expressions. - (line 6) -* 'm' in constraint: Simple Constraints. (line 17) -* machine attributes: Target Attributes. (line 6) -* machine description macros: Target Macros. (line 6) -* machine descriptions: Machine Desc. (line 6) -* machine mode conversions: Conversions. (line 6) -* machine modes: Machine Modes. (line 6) -* machine specific constraints: Machine Constraints. - (line 6) -* machine-independent predicates: Machine-Independent Predicates. - (line 6) -* macros, target description: Target Macros. (line 6) -* 'maddMN4' instruction pattern: Standard Names. (line 449) -* makefile fragment: Fragments. (line 6) -* makefile targets: Makefile. (line 6) -* MAKE_DECL_ONE_ONLY: Label Output. (line 246) -* make_safe_from: Expander Definitions. - (line 151) -* MALLOC_ABI_ALIGNMENT: Storage Layout. (line 168) -* Manipulating GIMPLE statements: Manipulating GIMPLE statements. - (line 6) -* marking roots: GGC Roots. (line 6) -* mark_hook: GTY Options. (line 181) -* MASK_RETURN_ADDR: Exception Region Output. - (line 34) -* matching constraint: Simple Constraints. (line 140) -* matching operands: Output Template. (line 49) -* match_dup: RTL Template. (line 73) -* match_dup <1>: define_peephole2. (line 28) -* 'match_dup' and attributes: Insn Lengths. (line 16) -* match_operand: RTL Template. (line 16) -* 'match_operand' and attributes: Expressions. (line 55) -* match_operator: RTL Template. (line 95) -* match_op_dup: RTL Template. (line 163) -* match_parallel: RTL Template. (line 172) -* match_par_dup: RTL Template. (line 219) -* match_scratch: RTL Template. (line 58) -* match_scratch <1>: define_peephole2. (line 28) -* 'match_test' and attributes: Expressions. (line 64) -* math library: Soft float library routines. - (line 6) -* math, in RTL: Arithmetic. (line 6) -* matherr: Library Calls. (line 59) -* MATH_LIBRARY: Misc. (line 502) -* 'maxM3' instruction pattern: Standard Names. (line 311) -* MAX_BITSIZE_MODE_ANY_INT: Machine Modes. (line 349) -* MAX_BITSIZE_MODE_ANY_MODE: Machine Modes. (line 355) -* MAX_BITS_PER_WORD: Storage Layout. (line 54) -* MAX_CONDITIONAL_EXECUTE: Misc. (line 524) -* MAX_FIXED_MODE_SIZE: Storage Layout. (line 431) -* MAX_MOVE_MAX: Misc. (line 105) -* MAX_OFILE_ALIGNMENT: Storage Layout. (line 203) -* MAX_REGS_PER_ADDRESS: Addressing Modes. (line 42) -* MAX_STACK_ALIGNMENT: Storage Layout. (line 197) -* maybe_undef: GTY Options. (line 190) -* may_trap_p, tree_could_trap_p: Edges. (line 114) -* mcount: Profiling. (line 12) -* MD_CAN_REDIRECT_BRANCH: Misc. (line 711) -* MD_EXEC_PREFIX: Driver. (line 267) -* MD_FALLBACK_FRAME_STATE_FOR: Exception Handling. (line 93) -* MD_HANDLE_UNWABI: Exception Handling. (line 112) -* MD_STARTFILE_PREFIX: Driver. (line 295) -* MD_STARTFILE_PREFIX_1: Driver. (line 300) -* mem: Regs and Memory. (line 370) -* 'mem' and '/c': Flags. (line 81) -* 'mem' and '/f': Flags. (line 85) -* 'mem' and '/j': Flags. (line 70) -* 'mem' and '/u': Flags. (line 134) -* 'mem' and '/v': Flags. (line 76) -* 'mem', RTL sharing: Sharing. (line 40) -* memory model: Memory model. (line 6) -* memory reference, nonoffsettable: Simple Constraints. (line 254) -* memory references in constraints: Simple Constraints. (line 17) -* 'memory_barrier' instruction pattern: Standard Names. (line 1587) -* MEMORY_MOVE_COST: Costs. (line 53) -* memory_operand: Machine-Independent Predicates. - (line 57) -* MEM_ADDR_SPACE: Special Accessors. (line 48) -* MEM_ALIAS_SET: Special Accessors. (line 9) -* MEM_ALIGN: Special Accessors. (line 45) -* MEM_EXPR: Special Accessors. (line 19) -* MEM_KEEP_ALIAS_SET_P: Flags. (line 70) -* MEM_NOTRAP_P: Flags. (line 81) -* MEM_OFFSET: Special Accessors. (line 31) -* MEM_OFFSET_KNOWN_P: Special Accessors. (line 27) -* MEM_POINTER: Flags. (line 85) -* MEM_READONLY_P: Flags. (line 134) -* MEM_REF: Storage References. (line 6) -* 'mem_signal_fenceMODE' instruction pattern: Standard Names. - (line 1857) -* MEM_SIZE: Special Accessors. (line 39) -* MEM_SIZE_KNOWN_P: Special Accessors. (line 35) -* 'mem_thread_fenceMODE' instruction pattern: Standard Names. - (line 1849) -* MEM_VOLATILE_P: Flags. (line 76) -* METHOD_TYPE: Types. (line 6) -* MINIMUM_ALIGNMENT: Storage Layout. (line 299) -* MINIMUM_ATOMIC_ALIGNMENT: Storage Layout. (line 176) -* 'minM3' instruction pattern: Standard Names. (line 311) -* minus: Arithmetic. (line 38) -* 'minus' and attributes: Expressions. (line 83) -* 'minus', canonicalization of: Insn Canonicalizations. - (line 27) -* MINUS_EXPR: Unary and Binary Expressions. - (line 6) -* MIN_UNITS_PER_WORD: Storage Layout. (line 64) -* MIPS coprocessor-definition macros: MIPS Coprocessors. (line 6) -* mnemonic attribute: Mnemonic Attribute. (line 6) -* mod: Arithmetic. (line 137) -* 'mod' and attributes: Expressions. (line 83) -* mode classes: Machine Modes. (line 221) -* mode iterators in '.md' files: Mode Iterators. (line 6) -* mode switching: Mode Switching. (line 6) -* MODES_TIEABLE_P: Values in Registers. - (line 127) -* MODE_ACCUM: Machine Modes. (line 251) -* MODE_AFTER: Mode Switching. (line 48) -* MODE_BASE_REG_CLASS: Register Classes. (line 116) -* MODE_BASE_REG_REG_CLASS: Register Classes. (line 122) -* MODE_CC: Machine Modes. (line 270) -* MODE_CC <1>: MODE_CC Condition Codes. - (line 6) -* MODE_CODE_BASE_REG_CLASS: Register Classes. (line 129) -* MODE_COMPLEX_FLOAT: Machine Modes. (line 262) -* MODE_COMPLEX_INT: Machine Modes. (line 259) -* MODE_DECIMAL_FLOAT: Machine Modes. (line 239) -* MODE_ENTRY: Mode Switching. (line 54) -* MODE_EXIT: Mode Switching. (line 60) -* MODE_FLOAT: Machine Modes. (line 235) -* MODE_FRACT: Machine Modes. (line 243) -* MODE_FUNCTION: Machine Modes. (line 266) -* MODE_INT: Machine Modes. (line 227) -* MODE_NEEDED: Mode Switching. (line 41) -* MODE_PARTIAL_INT: Machine Modes. (line 231) -* MODE_PRIORITY_TO_MODE: Mode Switching. (line 66) -* MODE_RANDOM: Machine Modes. (line 275) -* MODE_UACCUM: Machine Modes. (line 255) -* MODE_UFRACT: Machine Modes. (line 247) -* modifiers in constraints: Modifiers. (line 6) -* MODIFY_EXPR: Unary and Binary Expressions. - (line 6) -* MODIFY_JNI_METHOD_CALL: Misc. (line 798) -* 'modM3' instruction pattern: Standard Names. (line 276) -* modulo scheduling: RTL passes. (line 123) -* MOVE_BY_PIECES_P: Costs. (line 164) -* MOVE_MAX: Misc. (line 100) -* MOVE_MAX_PIECES: Costs. (line 170) -* MOVE_RATIO: Costs. (line 148) -* 'movM' instruction pattern: Standard Names. (line 11) -* 'movmemM' instruction pattern: Standard Names. (line 756) -* 'movmisalignM' instruction pattern: Standard Names. (line 125) -* 'movMODEcc' instruction pattern: Standard Names. (line 1050) -* 'movstr' instruction pattern: Standard Names. (line 791) -* 'movstrictM' instruction pattern: Standard Names. (line 119) -* 'msubMN4' instruction pattern: Standard Names. (line 472) -* 'mulhisi3' instruction pattern: Standard Names. (line 425) -* 'mulM3' instruction pattern: Standard Names. (line 276) -* 'mulqihi3' instruction pattern: Standard Names. (line 429) -* 'mulsidi3' instruction pattern: Standard Names. (line 429) -* mult: Arithmetic. (line 93) -* 'mult' and attributes: Expressions. (line 83) -* 'mult', canonicalization of: Insn Canonicalizations. - (line 27) -* 'mult', canonicalization of <1>: Insn Canonicalizations. - (line 91) -* MULTIARCH_DIRNAME: Target Fragment. (line 170) -* MULTILIB_DEFAULTS: Driver. (line 252) -* MULTILIB_DIRNAMES: Target Fragment. (line 44) -* MULTILIB_EXCEPTIONS: Target Fragment. (line 70) -* MULTILIB_EXTRA_OPTS: Target Fragment. (line 132) -* MULTILIB_MATCHES: Target Fragment. (line 63) -* MULTILIB_OPTIONS: Target Fragment. (line 24) -* MULTILIB_OSDIRNAMES: Target Fragment. (line 139) -* MULTILIB_REQUIRED: Target Fragment. (line 82) -* MULTILIB_REUSE: Target Fragment. (line 103) -* multiple alternative constraints: Multi-Alternative. (line 6) -* MULTIPLE_SYMBOL_SPACES: Misc. (line 482) -* multiplication: Arithmetic. (line 93) -* multiplication with signed saturation: Arithmetic. (line 93) -* multiplication with unsigned saturation: Arithmetic. (line 93) -* MULT_EXPR: Unary and Binary Expressions. - (line 6) -* MULT_HIGHPART_EXPR: Unary and Binary Expressions. - (line 6) -* 'n' in constraint: Simple Constraints. (line 73) -* name: Identifiers. (line 6) -* named address spaces: Named Address Spaces. - (line 6) -* named patterns and conditions: Patterns. (line 47) -* names, pattern: Standard Names. (line 6) -* namespace, scope: Namespaces. (line 6) -* NAMESPACE_DECL: Declarations. (line 6) -* NAMESPACE_DECL <1>: Namespaces. (line 6) -* NATIVE_SYSTEM_HEADER_COMPONENT: Driver. (line 322) -* ne: Comparisons. (line 56) -* 'ne' and attributes: Expressions. (line 83) -* 'nearbyintM2' instruction pattern: Standard Names. (line 666) -* neg: Arithmetic. (line 82) -* 'neg' and attributes: Expressions. (line 83) -* 'neg', canonicalization of: Insn Canonicalizations. - (line 27) -* NEGATE_EXPR: Unary and Binary Expressions. - (line 6) -* negation: Arithmetic. (line 82) -* negation with signed saturation: Arithmetic. (line 82) -* negation with unsigned saturation: Arithmetic. (line 82) -* 'negM2' instruction pattern: Standard Names. (line 538) -* nested functions, trampolines for: Trampolines. (line 6) -* nested_ptr: GTY Options. (line 198) -* next_bb, prev_bb, FOR_EACH_BB, FOR_ALL_BB: Basic Blocks. (line 25) -* NEXT_INSN: Insns. (line 30) -* NEXT_OBJC_RUNTIME: Library Calls. (line 82) -* NE_EXPR: Unary and Binary Expressions. - (line 6) -* nil: RTL Objects. (line 73) -* NM_FLAGS: Macros for Initialization. - (line 110) -* nondeterministic finite state automaton: Processor pipeline description. - (line 304) -* nonimmediate_operand: Machine-Independent Predicates. - (line 100) -* nonlocal goto handler: Edges. (line 171) -* 'nonlocal_goto' instruction pattern: Standard Names. (line 1419) -* 'nonlocal_goto_receiver' instruction pattern: Standard Names. - (line 1436) -* nonmemory_operand: Machine-Independent Predicates. - (line 96) -* nonoffsettable memory reference: Simple Constraints. (line 254) -* NON_LVALUE_EXPR: Unary and Binary Expressions. - (line 6) -* 'nop' instruction pattern: Standard Names. (line 1232) -* NOP_EXPR: Unary and Binary Expressions. - (line 6) -* normal predicates: Predicates. (line 31) -* not: Arithmetic. (line 155) -* 'not' and attributes: Expressions. (line 50) -* not equal: Comparisons. (line 56) -* 'not', canonicalization of: Insn Canonicalizations. - (line 27) -* note: Insns. (line 183) -* 'note' and '/i': Flags. (line 59) -* 'note' and '/v': Flags. (line 44) -* NOTE_INSN_BASIC_BLOCK: Basic Blocks. (line 50) -* NOTE_INSN_BASIC_BLOCK <1>: Basic Blocks. (line 52) -* NOTE_INSN_BLOCK_BEG: Insns. (line 208) -* NOTE_INSN_BLOCK_END: Insns. (line 208) -* NOTE_INSN_DELETED: Insns. (line 198) -* NOTE_INSN_DELETED_LABEL: Insns. (line 203) -* NOTE_INSN_EH_REGION_BEG: Insns. (line 214) -* NOTE_INSN_EH_REGION_END: Insns. (line 214) -* NOTE_INSN_FUNCTION_BEG: Insns. (line 221) -* NOTE_INSN_VAR_LOCATION: Insns. (line 225) -* NOTE_LINE_NUMBER: Insns. (line 183) -* NOTE_SOURCE_FILE: Insns. (line 183) -* NOTE_VAR_LOCATION: Insns. (line 225) -* NOTICE_UPDATE_CC: CC0 Condition Codes. - (line 30) -* NO_DBX_BNSYM_ENSYM: DBX Hooks. (line 25) -* NO_DBX_FUNCTION_END: DBX Hooks. (line 19) -* NO_DBX_GCC_MARKER: File Names and DBX. (line 27) -* NO_DBX_MAIN_SOURCE_DIRECTORY: File Names and DBX. (line 22) -* NO_DOLLAR_IN_LABEL: Label Output. (line 64) -* NO_DOT_IN_LABEL: Label Output. (line 70) -* NO_FUNCTION_CSE: Costs. (line 260) -* NO_IMPLICIT_EXTERN_C: Misc. (line 381) -* NO_PROFILE_COUNTERS: Profiling. (line 27) -* NO_REGS: Register Classes. (line 17) -* Number of iterations analysis: Number of iterations. - (line 6) -* NUM_MACHINE_MODES: Machine Modes. (line 288) -* NUM_MODES_FOR_MODE_SWITCHING: Mode Switching. (line 29) -* N_REG_CLASSES: Register Classes. (line 81) -* 'o' in constraint: Simple Constraints. (line 23) -* OBJC_GEN_METHOD_LABEL: Label Output. (line 447) -* OBJC_JBLEN: Misc. (line 991) -* OBJECT_FORMAT_COFF: Macros for Initialization. - (line 96) -* offsettable address: Simple Constraints. (line 23) -* OFFSET_TYPE: Types. (line 6) -* OImode: Machine Modes. (line 51) -* Omega a solver for linear programming problems: Omega. (line 6) -* OMP_ATOMIC: OpenMP. (line 6) -* OMP_CLAUSE: OpenMP. (line 6) -* OMP_CONTINUE: OpenMP. (line 6) -* OMP_CRITICAL: OpenMP. (line 6) -* OMP_FOR: OpenMP. (line 6) -* OMP_MASTER: OpenMP. (line 6) -* OMP_ORDERED: OpenMP. (line 6) -* OMP_PARALLEL: OpenMP. (line 6) -* OMP_RETURN: OpenMP. (line 6) -* OMP_SECTION: OpenMP. (line 6) -* OMP_SECTIONS: OpenMP. (line 6) -* OMP_SINGLE: OpenMP. (line 6) -* 'one_cmplM2' instruction pattern: Standard Names. (line 753) -* operand access: Accessors. (line 6) -* Operand Access Routines: SSA Operands. (line 116) -* operand constraints: Constraints. (line 6) -* Operand Iterators: SSA Operands. (line 116) -* operand predicates: Predicates. (line 6) -* operand substitution: Output Template. (line 6) -* Operands: Operands. (line 6) -* operands: SSA Operands. (line 6) -* operands <1>: Patterns. (line 53) -* operator predicates: Predicates. (line 6) -* 'optc-gen.awk': Options. (line 6) -* OPTGROUP_ALL: Optimization groups. - (line 25) -* OPTGROUP_INLINE: Optimization groups. - (line 15) -* OPTGROUP_IPA: Optimization groups. - (line 9) -* OPTGROUP_LOOP: Optimization groups. - (line 12) -* OPTGROUP_OTHER: Optimization groups. - (line 21) -* OPTGROUP_VEC: Optimization groups. - (line 18) -* optimization dumps: Optimization info. (line 6) -* optimization groups: Optimization groups. - (line 6) -* optimization info file names: Dump files and streams. - (line 6) -* Optimization infrastructure for GIMPLE: Tree SSA. (line 6) -* OPTIMIZE_MODE_SWITCHING: Mode Switching. (line 8) -* option specification files: Options. (line 6) -* optional hardware or system features: Run-time Target. (line 59) -* options, directory search: Including Patterns. (line 45) -* OPTION_DEFAULT_SPECS: Driver. (line 25) -* order of register allocation: Allocation Order. (line 6) -* ordered_comparison_operator: Machine-Independent Predicates. - (line 115) -* ORDERED_EXPR: Unary and Binary Expressions. - (line 6) -* Ordering of Patterns: Pattern Ordering. (line 6) -* ORIGINAL_REGNO: Special Accessors. (line 53) -* other register constraints: Simple Constraints. (line 171) -* outgoing_args_size: Stack Arguments. (line 48) -* OUTGOING_REGNO: Register Basics. (line 94) -* OUTGOING_REG_PARM_STACK_SPACE: Stack Arguments. (line 73) -* output of assembler code: File Framework. (line 6) -* output statements: Output Statement. (line 6) -* output templates: Output Template. (line 6) -* output_asm_insn: Output Statement. (line 52) -* OUTPUT_QUOTED_STRING: File Framework. (line 106) -* OVERLAPPING_REGISTER_NAMES: Instruction Output. (line 20) -* OVERLOAD: Functions for C++. (line 6) -* OVERRIDE_ABI_FORMAT: Register Arguments. (line 139) -* OVL_CURRENT: Functions for C++. (line 6) -* OVL_NEXT: Functions for C++. (line 6) -* 'p' in constraint: Simple Constraints. (line 162) -* PAD_VARARGS_DOWN: Register Arguments. (line 220) -* parallel: Side Effects. (line 209) -* parameters, c++ abi: C++ ABI. (line 6) -* parameters, miscellaneous: Misc. (line 6) -* parameters, precompiled headers: PCH Target. (line 6) -* paramN_is: GTY Options. (line 138) -* param_is: GTY Options. (line 119) -* parity: Arithmetic. (line 243) -* 'parityM2' instruction pattern: Standard Names. (line 747) -* PARM_BOUNDARY: Storage Layout. (line 133) -* PARM_DECL: Declarations. (line 6) -* PARSE_LDD_OUTPUT: Macros for Initialization. - (line 125) -* pass dumps: Passes. (line 6) -* passes and files of the compiler: Passes. (line 6) -* passing arguments: Interface. (line 36) -* pass_duplicate_computed_gotos: Edges. (line 161) -* PATH_SEPARATOR: Filesystem. (line 31) -* PATTERN: Insns. (line 284) -* pattern conditions: Patterns. (line 43) -* pattern names: Standard Names. (line 6) -* Pattern Ordering: Pattern Ordering. (line 6) -* patterns: Patterns. (line 6) -* pc: Regs and Memory. (line 357) -* 'pc' and attributes: Insn Lengths. (line 20) -* 'pc', RTL sharing: Sharing. (line 25) -* PCC_BITFIELD_TYPE_MATTERS: Storage Layout. (line 325) -* PCC_STATIC_STRUCT_RETURN: Aggregate Return. (line 64) -* PC_REGNUM: Register Basics. (line 108) -* pc_rtx: Regs and Memory. (line 362) -* PDImode: Machine Modes. (line 40) -* peephole optimization, RTL representation: Side Effects. (line 243) -* peephole optimizer definitions: Peephole Definitions. - (line 6) -* per-function data: Per-Function Data. (line 6) -* percent sign: Output Template. (line 6) -* PHI nodes: SSA. (line 31) -* PIC: PIC. (line 6) -* PIC_OFFSET_TABLE_REGNUM: PIC. (line 15) -* PIC_OFFSET_TABLE_REG_CALL_CLOBBERED: PIC. (line 25) -* pipeline hazard recognizer: Processor pipeline description. - (line 6) -* pipeline hazard recognizer <1>: Processor pipeline description. - (line 53) -* Plugins: Plugins. (line 6) -* plus: Arithmetic. (line 14) -* 'plus' and attributes: Expressions. (line 83) -* 'plus', canonicalization of: Insn Canonicalizations. - (line 27) -* PLUS_EXPR: Unary and Binary Expressions. - (line 6) -* Pmode: Misc. (line 329) -* pmode_register_operand: Machine-Independent Predicates. - (line 34) -* pointer: Types. (line 6) -* POINTERS_EXTEND_UNSIGNED: Storage Layout. (line 76) -* POINTER_PLUS_EXPR: Unary and Binary Expressions. - (line 6) -* POINTER_SIZE: Storage Layout. (line 70) -* POINTER_TYPE: Types. (line 6) -* popcount: Arithmetic. (line 239) -* 'popcountM2' instruction pattern: Standard Names. (line 741) -* pops_args: Function Entry. (line 104) -* pop_operand: Machine-Independent Predicates. - (line 87) -* portability: Portability. (line 6) -* position independent code: PIC. (line 6) -* POSTDECREMENT_EXPR: Unary and Binary Expressions. - (line 6) -* POSTINCREMENT_EXPR: Unary and Binary Expressions. - (line 6) -* post_dec: Incdec. (line 25) -* post_inc: Incdec. (line 30) -* post_modify: Incdec. (line 33) -* post_order_compute, inverted_post_order_compute, walk_dominator_tree: Basic Blocks. - (line 34) -* POWI_MAX_MULTS: Misc. (line 860) -* 'powM3' instruction pattern: Standard Names. (line 615) -* pragma: Misc. (line 387) -* PREDECREMENT_EXPR: Unary and Binary Expressions. - (line 6) -* predefined macros: Run-time Target. (line 6) -* predicates: Predicates. (line 6) -* predicates and machine modes: Predicates. (line 31) -* predication: Conditional Execution. - (line 6) -* predict.def: Profile information. - (line 24) -* PREFERRED_DEBUGGING_TYPE: All Debuggers. (line 41) -* PREFERRED_RELOAD_CLASS: Register Classes. (line 249) -* PREFERRED_STACK_BOUNDARY: Storage Layout. (line 147) -* prefetch: Side Effects. (line 323) -* 'prefetch' and '/v': Flags. (line 214) -* 'prefetch' instruction pattern: Standard Names. (line 1562) -* PREFETCH_SCHEDULE_BARRIER_P: Flags. (line 214) -* PREINCREMENT_EXPR: Unary and Binary Expressions. - (line 6) -* presence_set: Processor pipeline description. - (line 223) -* preserving SSA form: SSA. (line 74) -* preserving virtual SSA form: SSA. (line 182) -* pretend_args_size: Function Entry. (line 110) -* prev_active_insn: define_peephole. (line 60) -* PREV_INSN: Insns. (line 26) -* pre_dec: Incdec. (line 8) -* PRE_GCC3_DWARF_FRAME_REGISTERS: Frame Registers. (line 126) -* pre_inc: Incdec. (line 22) -* pre_modify: Incdec. (line 52) -* PRINT_OPERAND: Instruction Output. (line 95) -* PRINT_OPERAND_ADDRESS: Instruction Output. (line 122) -* PRINT_OPERAND_PUNCT_VALID_P: Instruction Output. (line 115) -* 'probe_stack' instruction pattern: Standard Names. (line 1411) -* 'probe_stack_address' instruction pattern: Standard Names. (line 1404) -* processor functional units: Processor pipeline description. - (line 6) -* processor functional units <1>: Processor pipeline description. - (line 68) -* processor pipeline description: Processor pipeline description. - (line 6) -* product: Arithmetic. (line 93) -* profile feedback: Profile information. - (line 14) -* profile representation: Profile information. - (line 6) -* PROFILE_BEFORE_PROLOGUE: Profiling. (line 34) -* PROFILE_HOOK: Profiling. (line 22) -* profiling, code generation: Profiling. (line 6) -* program counter: Regs and Memory. (line 358) -* prologue: Function Entry. (line 6) -* 'prologue' instruction pattern: Standard Names. (line 1500) -* PROMOTE_MODE: Storage Layout. (line 87) -* pseudo registers: Regs and Memory. (line 9) -* PSImode: Machine Modes. (line 32) -* PTRDIFF_TYPE: Type Layout. (line 200) -* purge_dead_edges: Edges. (line 103) -* purge_dead_edges <1>: Maintaining the CFG. - (line 81) -* push address instruction: Simple Constraints. (line 162) -* 'pushM1' instruction pattern: Standard Names. (line 253) -* PUSH_ARGS: Stack Arguments. (line 17) -* PUSH_ARGS_REVERSED: Stack Arguments. (line 25) -* push_operand: Machine-Independent Predicates. - (line 80) -* push_reload: Addressing Modes. (line 176) -* PUSH_ROUNDING: Stack Arguments. (line 31) -* PUT_CODE: RTL Objects. (line 47) -* PUT_MODE: Machine Modes. (line 285) -* PUT_REG_NOTE_KIND: Insns. (line 346) -* PUT_SDB_: SDB and DWARF. (line 105) -* QCmode: Machine Modes. (line 199) -* QFmode: Machine Modes. (line 57) -* QImode: Machine Modes. (line 25) -* 'QImode', in 'insn': Insns. (line 268) -* QQmode: Machine Modes. (line 106) -* qualified type: Types. (line 6) -* qualified type <1>: Types for C++. (line 6) -* querying function unit reservations: Processor pipeline description. - (line 90) -* question mark: Multi-Alternative. (line 41) -* quotient: Arithmetic. (line 117) -* 'r' in constraint: Simple Constraints. (line 64) -* RDIV_EXPR: Unary and Binary Expressions. - (line 6) -* READONLY_DATA_SECTION_ASM_OP: Sections. (line 62) -* real operands: SSA Operands. (line 6) -* REALPART_EXPR: Unary and Binary Expressions. - (line 6) -* REAL_ARITHMETIC: Floating Point. (line 64) -* REAL_CST: Constant expressions. - (line 6) -* REAL_LIBGCC_SPEC: Driver. (line 124) -* REAL_NM_FILE_NAME: Macros for Initialization. - (line 105) -* REAL_TYPE: Types. (line 6) -* REAL_VALUES_EQUAL: Floating Point. (line 31) -* REAL_VALUES_LESS: Floating Point. (line 37) -* REAL_VALUE_ABS: Floating Point. (line 81) -* REAL_VALUE_ATOF: Floating Point. (line 48) -* REAL_VALUE_FIX: Floating Point. (line 40) -* REAL_VALUE_FROM_INT: Floating Point. (line 90) -* REAL_VALUE_ISINF: Floating Point. (line 58) -* REAL_VALUE_ISNAN: Floating Point. (line 61) -* REAL_VALUE_NEGATE: Floating Point. (line 78) -* REAL_VALUE_NEGATIVE: Floating Point. (line 55) -* REAL_VALUE_TO_INT: Floating Point. (line 84) -* REAL_VALUE_TO_TARGET_DECIMAL128: Data Output. (line 143) -* REAL_VALUE_TO_TARGET_DECIMAL32: Data Output. (line 141) -* REAL_VALUE_TO_TARGET_DECIMAL64: Data Output. (line 142) -* REAL_VALUE_TO_TARGET_DOUBLE: Data Output. (line 139) -* REAL_VALUE_TO_TARGET_LONG_DOUBLE: Data Output. (line 140) -* REAL_VALUE_TO_TARGET_SINGLE: Data Output. (line 138) -* REAL_VALUE_TYPE: Floating Point. (line 25) -* REAL_VALUE_UNSIGNED_FIX: Floating Point. (line 43) -* recognizing insns: RTL Template. (line 6) -* recog_data.operand: Instruction Output. (line 54) -* RECORD_TYPE: Types. (line 6) -* RECORD_TYPE <1>: Classes. (line 6) -* redirect_edge_and_branch: Profile information. - (line 71) -* redirect_edge_and_branch, redirect_jump: Maintaining the CFG. - (line 90) -* 'reduc_smax_M' instruction pattern: Standard Names. (line 317) -* 'reduc_smin_M' instruction pattern: Standard Names. (line 317) -* 'reduc_splus_M' instruction pattern: Standard Names. (line 329) -* 'reduc_umax_M' instruction pattern: Standard Names. (line 323) -* 'reduc_umin_M' instruction pattern: Standard Names. (line 323) -* 'reduc_uplus_M' instruction pattern: Standard Names. (line 335) -* reference: Types. (line 6) -* REFERENCE_TYPE: Types. (line 6) -* reg: Regs and Memory. (line 9) -* 'reg' and '/f': Flags. (line 94) -* 'reg' and '/i': Flags. (line 89) -* 'reg' and '/v': Flags. (line 98) -* 'reg', RTL sharing: Sharing. (line 17) -* regclass_for_constraint: C Constraint Interface. - (line 58) -* register allocation order: Allocation Order. (line 6) -* register class definitions: Register Classes. (line 6) -* register class preference constraints: Class Preferences. (line 6) -* register pairs: Values in Registers. - (line 69) -* Register Transfer Language (RTL): RTL. (line 6) -* register usage: Registers. (line 6) -* registers arguments: Register Arguments. (line 6) -* registers in constraints: Simple Constraints. (line 64) -* REGISTER_MOVE_COST: Costs. (line 9) -* REGISTER_NAMES: Instruction Output. (line 8) -* register_operand: Machine-Independent Predicates. - (line 29) -* REGISTER_PREFIX: Instruction Output. (line 150) -* REGISTER_TARGET_PRAGMAS: Misc. (line 387) -* REGMODE_NATURAL_SIZE: Values in Registers. - (line 49) -* REGNO_MODE_CODE_OK_FOR_BASE_P: Register Classes. (line 172) -* REGNO_MODE_OK_FOR_BASE_P: Register Classes. (line 150) -* REGNO_MODE_OK_FOR_REG_BASE_P: Register Classes. (line 160) -* REGNO_OK_FOR_BASE_P: Register Classes. (line 146) -* REGNO_OK_FOR_INDEX_P: Register Classes. (line 186) -* REGNO_REG_CLASS: Register Classes. (line 105) -* regs_ever_live: Function Entry. (line 21) -* regular expressions: Processor pipeline description. - (line 6) -* regular expressions <1>: Processor pipeline description. - (line 105) -* REG_ALLOC_ORDER: Allocation Order. (line 8) -* REG_BR_PRED: Insns. (line 526) -* REG_BR_PROB: Insns. (line 519) -* REG_BR_PROB_BASE, BB_FREQ_BASE, count: Profile information. - (line 82) -* REG_BR_PROB_BASE, EDGE_FREQUENCY: Profile information. - (line 52) -* REG_CC_SETTER: Insns. (line 491) -* REG_CC_USER: Insns. (line 491) -* reg_class_contents: Register Basics. (line 59) -* REG_CLASS_CONTENTS: Register Classes. (line 91) -* REG_CLASS_FROM_CONSTRAINT: Old Constraints. (line 33) -* REG_CLASS_FROM_LETTER: Old Constraints. (line 25) -* REG_CLASS_NAMES: Register Classes. (line 86) -* REG_CROSSING_JUMP: Insns. (line 405) -* REG_DEAD: Insns. (line 357) -* REG_DEAD, REG_UNUSED: Liveness information. - (line 32) -* REG_DEP_ANTI: Insns. (line 513) -* REG_DEP_OUTPUT: Insns. (line 509) -* REG_DEP_TRUE: Insns. (line 506) -* REG_EH_REGION, EDGE_ABNORMAL_CALL: Edges. (line 109) -* REG_EQUAL: Insns. (line 420) -* REG_EQUIV: Insns. (line 420) -* REG_EXPR: Special Accessors. (line 58) -* REG_FRAME_RELATED_EXPR: Insns. (line 532) -* REG_FUNCTION_VALUE_P: Flags. (line 89) -* REG_INC: Insns. (line 373) -* 'reg_label' and '/v': Flags. (line 65) -* REG_LABEL_OPERAND: Insns. (line 387) -* REG_LABEL_TARGET: Insns. (line 396) -* reg_names: Register Basics. (line 59) -* reg_names <1>: Instruction Output. (line 107) -* REG_NONNEG: Insns. (line 379) -* REG_NOTES: Insns. (line 321) -* REG_NOTE_KIND: Insns. (line 346) -* REG_OFFSET: Special Accessors. (line 62) -* REG_OK_STRICT: Addressing Modes. (line 99) -* REG_PARM_STACK_SPACE: Stack Arguments. (line 58) -* 'REG_PARM_STACK_SPACE', and 'TARGET_FUNCTION_ARG': Register Arguments. - (line 50) -* REG_POINTER: Flags. (line 94) -* REG_SETJMP: Insns. (line 414) -* REG_UNUSED: Insns. (line 366) -* REG_USERVAR_P: Flags. (line 98) -* REG_VALUE_IN_UNWIND_CONTEXT: Frame Registers. (line 158) -* REG_WORDS_BIG_ENDIAN: Storage Layout. (line 35) -* relative costs: Costs. (line 6) -* RELATIVE_PREFIX_NOT_LINKDIR: Driver. (line 262) -* reloading: RTL passes. (line 170) -* reload_completed: Standard Names. (line 1199) -* 'reload_in' instruction pattern: Standard Names. (line 98) -* reload_in_progress: Standard Names. (line 57) -* 'reload_out' instruction pattern: Standard Names. (line 98) -* remainder: Arithmetic. (line 137) -* 'remainderM3' instruction pattern: Standard Names. (line 561) -* reorder: GTY Options. (line 224) -* representation of RTL: RTL. (line 6) -* reservation delays: Processor pipeline description. - (line 6) -* 'restore_stack_block' instruction pattern: Standard Names. (line 1325) -* 'restore_stack_function' instruction pattern: Standard Names. - (line 1325) -* 'restore_stack_nonlocal' instruction pattern: Standard Names. - (line 1325) -* rest_of_decl_compilation: Parsing pass. (line 51) -* rest_of_type_compilation: Parsing pass. (line 51) -* RESULT_DECL: Declarations. (line 6) -* return: Side Effects. (line 72) -* 'return' instruction pattern: Standard Names. (line 1173) -* return values in registers: Scalar Return. (line 6) -* returning aggregate values: Aggregate Return. (line 6) -* returning structures and unions: Interface. (line 10) -* RETURN_ADDRESS_POINTER_REGNUM: Frame Registers. (line 64) -* RETURN_ADDR_IN_PREVIOUS_FRAME: Frame Layout. (line 133) -* RETURN_ADDR_OFFSET: Exception Handling. (line 59) -* RETURN_ADDR_RTX: Frame Layout. (line 122) -* RETURN_EXPR: Statements for C++. (line 6) -* RETURN_STMT: Statements for C++. (line 6) -* return_val: Flags. (line 274) -* 'return_val', in 'call_insn': Flags. (line 24) -* 'return_val', in 'reg': Flags. (line 89) -* 'return_val', in 'symbol_ref': Flags. (line 202) -* reverse probability: Profile information. - (line 66) -* REVERSE_CONDITION: MODE_CC Condition Codes. - (line 90) -* REVERSIBLE_CC_MODE: MODE_CC Condition Codes. - (line 76) -* right rotate: Arithmetic. (line 196) -* right shift: Arithmetic. (line 191) -* 'rintM2' instruction pattern: Standard Names. (line 674) -* RISC: Processor pipeline description. - (line 6) -* RISC <1>: Processor pipeline description. - (line 223) -* roots, marking: GGC Roots. (line 6) -* rotate: Arithmetic. (line 196) -* rotate <1>: Arithmetic. (line 196) -* rotatert: Arithmetic. (line 196) -* 'rotlM3' instruction pattern: Standard Names. (line 526) -* 'rotrM3' instruction pattern: Standard Names. (line 526) -* 'roundM2' instruction pattern: Standard Names. (line 650) -* ROUND_DIV_EXPR: Unary and Binary Expressions. - (line 6) -* ROUND_MOD_EXPR: Unary and Binary Expressions. - (line 6) -* ROUND_TOWARDS_ZERO: Storage Layout. (line 474) -* ROUND_TYPE_ALIGN: Storage Layout. (line 422) -* RSHIFT_EXPR: Unary and Binary Expressions. - (line 6) -* RTL addition: Arithmetic. (line 14) -* RTL addition with signed saturation: Arithmetic. (line 14) -* RTL addition with unsigned saturation: Arithmetic. (line 14) -* RTL classes: RTL Classes. (line 6) -* RTL comparison: Arithmetic. (line 46) -* RTL comparison operations: Comparisons. (line 6) -* RTL constant expression types: Constants. (line 6) -* RTL constants: Constants. (line 6) -* RTL declarations: RTL Declarations. (line 6) -* RTL difference: Arithmetic. (line 38) -* RTL expression: RTL Objects. (line 6) -* RTL expressions for arithmetic: Arithmetic. (line 6) -* RTL format: RTL Classes. (line 72) -* RTL format characters: RTL Classes. (line 77) -* RTL function-call insns: Calls. (line 6) -* RTL insn template: RTL Template. (line 6) -* RTL integers: RTL Objects. (line 6) -* RTL memory expressions: Regs and Memory. (line 6) -* RTL object types: RTL Objects. (line 6) -* RTL postdecrement: Incdec. (line 6) -* RTL postincrement: Incdec. (line 6) -* RTL predecrement: Incdec. (line 6) -* RTL preincrement: Incdec. (line 6) -* RTL register expressions: Regs and Memory. (line 6) -* RTL representation: RTL. (line 6) -* RTL side effect expressions: Side Effects. (line 6) -* RTL strings: RTL Objects. (line 6) -* RTL structure sharing assumptions: Sharing. (line 6) -* RTL subtraction: Arithmetic. (line 38) -* RTL subtraction with signed saturation: Arithmetic. (line 38) -* RTL subtraction with unsigned saturation: Arithmetic. (line 38) -* RTL sum: Arithmetic. (line 14) -* RTL vectors: RTL Objects. (line 6) -* RTL_CONST_CALL_P: Flags. (line 19) -* RTL_CONST_OR_PURE_CALL_P: Flags. (line 29) -* RTL_LOOPING_CONST_OR_PURE_CALL_P: Flags. (line 33) -* RTL_PURE_CALL_P: Flags. (line 24) -* RTX (See RTL): RTL Objects. (line 6) -* RTX codes, classes of: RTL Classes. (line 6) -* RTX_FRAME_RELATED_P: Flags. (line 107) -* run-time conventions: Interface. (line 6) -* run-time target specification: Run-time Target. (line 6) -* 's' in constraint: Simple Constraints. (line 100) -* same_type_p: Types. (line 86) -* SAmode: Machine Modes. (line 150) -* 'satfractMN2' instruction pattern: Standard Names. (line 938) -* 'satfractunsMN2' instruction pattern: Standard Names. (line 951) -* satisfies_constraint_: C Constraint Interface. - (line 46) -* sat_fract: Conversions. (line 90) -* SAVE_EXPR: Unary and Binary Expressions. - (line 6) -* 'save_stack_block' instruction pattern: Standard Names. (line 1325) -* 'save_stack_function' instruction pattern: Standard Names. (line 1325) -* 'save_stack_nonlocal' instruction pattern: Standard Names. (line 1325) -* SBSS_SECTION_ASM_OP: Sections. (line 75) -* Scalar evolutions: Scalar evolutions. (line 6) -* scalars, returned as values: Scalar Return. (line 6) -* SCHED_GROUP_P: Flags. (line 148) -* SCmode: Machine Modes. (line 199) -* scratch: Regs and Memory. (line 294) -* scratch operands: Regs and Memory. (line 294) -* 'scratch', RTL sharing: Sharing. (line 35) -* scratch_operand: Machine-Independent Predicates. - (line 49) -* SDATA_SECTION_ASM_OP: Sections. (line 57) -* SDB_ALLOW_FORWARD_REFERENCES: SDB and DWARF. (line 123) -* SDB_ALLOW_UNKNOWN_REFERENCES: SDB and DWARF. (line 118) -* SDB_DEBUGGING_INFO: SDB and DWARF. (line 8) -* SDB_DELIM: SDB and DWARF. (line 111) -* SDB_OUTPUT_SOURCE_LINE: SDB and DWARF. (line 128) -* SDmode: Machine Modes. (line 88) -* 'sdot_prodM' instruction pattern: Standard Names. (line 341) -* search options: Including Patterns. (line 45) -* SECONDARY_INPUT_RELOAD_CLASS: Register Classes. (line 391) -* SECONDARY_MEMORY_NEEDED: Register Classes. (line 447) -* SECONDARY_MEMORY_NEEDED_MODE: Register Classes. (line 466) -* SECONDARY_MEMORY_NEEDED_RTX: Register Classes. (line 457) -* SECONDARY_OUTPUT_RELOAD_CLASS: Register Classes. (line 392) -* SECONDARY_RELOAD_CLASS: Register Classes. (line 390) -* SELECT_CC_MODE: MODE_CC Condition Codes. - (line 6) -* sequence: Side Effects. (line 258) -* Sequence iterators: Sequence iterators. (line 6) -* set: Side Effects. (line 15) -* 'set' and '/f': Flags. (line 107) -* 'setmemM' instruction pattern: Standard Names. (line 802) -* SETUP_FRAME_ADDRESSES: Frame Layout. (line 100) -* SET_ASM_OP: Label Output. (line 416) -* SET_ASM_OP <1>: Label Output. (line 427) -* set_attr: Tagging Insns. (line 31) -* set_attr_alternative: Tagging Insns. (line 49) -* set_bb_seq: GIMPLE sequences. (line 75) -* SET_BY_PIECES_P: Costs. (line 205) -* SET_DEST: Side Effects. (line 69) -* SET_IS_RETURN_P: Flags. (line 157) -* SET_LABEL_KIND: Insns. (line 146) -* set_optab_libfunc: Library Calls. (line 15) -* SET_RATIO: Costs. (line 193) -* SET_SRC: Side Effects. (line 69) -* 'set_thread_pointerMODE' instruction pattern: Standard Names. - (line 1869) -* SET_TYPE_STRUCTURAL_EQUALITY: Types. (line 6) -* SET_TYPE_STRUCTURAL_EQUALITY <1>: Types. (line 81) -* SFmode: Machine Modes. (line 69) -* SF_SIZE: Type Layout. (line 135) -* sharing of RTL components: Sharing. (line 6) -* shift: Arithmetic. (line 174) -* SHIFT_COUNT_TRUNCATED: Misc. (line 112) -* SHLIB_SUFFIX: Macros for Initialization. - (line 133) -* SHORT_ACCUM_TYPE_SIZE: Type Layout. (line 82) -* SHORT_FRACT_TYPE_SIZE: Type Layout. (line 62) -* SHORT_IMMEDIATES_SIGN_EXTEND: Misc. (line 86) -* SHORT_TYPE_SIZE: Type Layout. (line 15) -* 'sibcall_epilogue' instruction pattern: Standard Names. (line 1532) -* sibling call: Edges. (line 121) -* SIBLING_CALL_P: Flags. (line 161) -* signed division: Arithmetic. (line 117) -* signed division with signed saturation: Arithmetic. (line 117) -* signed maximum: Arithmetic. (line 142) -* signed minimum: Arithmetic. (line 142) -* sign_extend: Conversions. (line 23) -* sign_extract: Bit-Fields. (line 8) -* 'sign_extract', canonicalization of: Insn Canonicalizations. - (line 87) -* SIG_ATOMIC_TYPE: Type Layout. (line 251) -* SImode: Machine Modes. (line 37) -* simple constraints: Simple Constraints. (line 6) -* simple_return: Side Effects. (line 86) -* 'simple_return' instruction pattern: Standard Names. (line 1188) -* 'sincosM3' instruction pattern: Standard Names. (line 586) -* 'sinM2' instruction pattern: Standard Names. (line 578) -* SIZETYPE: Type Layout. (line 190) -* SIZE_ASM_OP: Label Output. (line 33) -* SIZE_TYPE: Type Layout. (line 174) -* skip: GTY Options. (line 76) -* SLOW_BYTE_ACCESS: Costs. (line 117) -* SLOW_UNALIGNED_ACCESS: Costs. (line 132) -* smax: Arithmetic. (line 142) -* smin: Arithmetic. (line 142) -* sms, swing, software pipelining: RTL passes. (line 123) -* 'smulM3_highpart' instruction pattern: Standard Names. (line 441) -* soft float library: Soft float library routines. - (line 6) -* special: GTY Options. (line 311) -* special predicates: Predicates. (line 31) -* SPECS: Target Fragment. (line 191) -* speed of instructions: Costs. (line 6) -* splitting instructions: Insn Splitting. (line 6) -* split_block: Maintaining the CFG. - (line 97) -* SQmode: Machine Modes. (line 114) -* sqrt: Arithmetic. (line 207) -* 'sqrtM2' instruction pattern: Standard Names. (line 544) -* square root: Arithmetic. (line 207) -* SSA: SSA. (line 6) -* 'ssaddM3' instruction pattern: Standard Names. (line 276) -* 'ssashlM3' instruction pattern: Standard Names. (line 516) -* SSA_NAME_DEF_STMT: SSA. (line 216) -* SSA_NAME_VERSION: SSA. (line 221) -* 'ssdivM3' instruction pattern: Standard Names. (line 276) -* 'ssmaddMN4' instruction pattern: Standard Names. (line 464) -* 'ssmsubMN4' instruction pattern: Standard Names. (line 488) -* 'ssmulM3' instruction pattern: Standard Names. (line 276) -* 'ssnegM2' instruction pattern: Standard Names. (line 538) -* 'sssubM3' instruction pattern: Standard Names. (line 276) -* 'ssum_widenM3' instruction pattern: Standard Names. (line 350) -* ss_abs: Arithmetic. (line 201) -* ss_ashift: Arithmetic. (line 174) -* ss_div: Arithmetic. (line 117) -* ss_minus: Arithmetic. (line 38) -* ss_mult: Arithmetic. (line 93) -* ss_neg: Arithmetic. (line 82) -* ss_plus: Arithmetic. (line 14) -* ss_truncate: Conversions. (line 43) -* stack arguments: Stack Arguments. (line 6) -* stack frame layout: Frame Layout. (line 6) -* stack smashing protection: Stack Smashing Protection. - (line 6) -* STACK_ALIGNMENT_NEEDED: Frame Layout. (line 47) -* STACK_BOUNDARY: Storage Layout. (line 139) -* STACK_CHECK_BUILTIN: Stack Checking. (line 31) -* STACK_CHECK_FIXED_FRAME_SIZE: Stack Checking. (line 82) -* STACK_CHECK_MAX_FRAME_SIZE: Stack Checking. (line 73) -* STACK_CHECK_MAX_VAR_SIZE: Stack Checking. (line 89) -* STACK_CHECK_MOVING_SP: Stack Checking. (line 53) -* STACK_CHECK_PROBE_INTERVAL_EXP: Stack Checking. (line 45) -* STACK_CHECK_PROTECT: Stack Checking. (line 62) -* STACK_CHECK_STATIC_BUILTIN: Stack Checking. (line 38) -* STACK_DYNAMIC_OFFSET: Frame Layout. (line 73) -* 'STACK_DYNAMIC_OFFSET' and virtual registers: Regs and Memory. - (line 83) -* STACK_GROWS_DOWNWARD: Frame Layout. (line 8) -* STACK_PARMS_IN_REG_PARM_AREA: Stack Arguments. (line 83) -* STACK_POINTER_OFFSET: Frame Layout. (line 57) -* 'STACK_POINTER_OFFSET' and virtual registers: Regs and Memory. - (line 93) -* STACK_POINTER_REGNUM: Frame Registers. (line 8) -* 'STACK_POINTER_REGNUM' and virtual registers: Regs and Memory. - (line 83) -* stack_pointer_rtx: Frame Registers. (line 104) -* 'stack_protect_set' instruction pattern: Standard Names. (line 1879) -* 'stack_protect_test' instruction pattern: Standard Names. (line 1890) -* STACK_PUSH_CODE: Frame Layout. (line 16) -* STACK_REGS: Stack Registers. (line 19) -* STACK_REG_COVER_CLASS: Stack Registers. (line 22) -* STACK_SAVEAREA_MODE: Storage Layout. (line 438) -* STACK_SIZE_MODE: Storage Layout. (line 449) -* STACK_SLOT_ALIGNMENT: Storage Layout. (line 270) -* standard pattern names: Standard Names. (line 6) -* STANDARD_STARTFILE_PREFIX: Driver. (line 274) -* STANDARD_STARTFILE_PREFIX_1: Driver. (line 281) -* STANDARD_STARTFILE_PREFIX_2: Driver. (line 288) -* STARTFILE_SPEC: Driver. (line 147) -* STARTING_FRAME_OFFSET: Frame Layout. (line 38) -* 'STARTING_FRAME_OFFSET' and virtual registers: Regs and Memory. - (line 74) -* Statement and operand traversals: Statement and operand traversals. - (line 6) -* Statement Sequences: Statement Sequences. - (line 6) -* Statements: Statements. (line 6) -* statements: Function Properties. - (line 6) -* statements <1>: Statements for C++. (line 6) -* Static profile estimation: Profile information. - (line 24) -* static single assignment: SSA. (line 6) -* STATIC_CHAIN_INCOMING_REGNUM: Frame Registers. (line 77) -* STATIC_CHAIN_REGNUM: Frame Registers. (line 76) -* 'stdarg.h' and register arguments: Register Arguments. (line 45) -* STDC_0_IN_SYSTEM_HEADERS: Misc. (line 350) -* STMT_EXPR: Unary and Binary Expressions. - (line 6) -* STMT_IS_FULL_EXPR_P: Statements for C++. (line 22) -* storage layout: Storage Layout. (line 6) -* STORE_BY_PIECES_P: Costs. (line 212) -* STORE_FLAG_VALUE: Misc. (line 201) -* 'store_multiple' instruction pattern: Standard Names. (line 159) -* strcpy: Storage Layout. (line 223) -* STRICT_ALIGNMENT: Storage Layout. (line 320) -* strict_low_part: RTL Declarations. (line 9) -* strict_memory_address_p: Addressing Modes. (line 186) -* STRING_CST: Constant expressions. - (line 6) -* STRING_POOL_ADDRESS_P: Flags. (line 165) -* 'strlenM' instruction pattern: Standard Names. (line 873) -* structure value address: Aggregate Return. (line 6) -* structures, returning: Interface. (line 10) -* STRUCTURE_SIZE_BOUNDARY: Storage Layout. (line 312) -* 'subM3' instruction pattern: Standard Names. (line 276) -* SUBOBJECT: Statements for C++. (line 6) -* SUBOBJECT_CLEANUP: Statements for C++. (line 6) -* subreg: Regs and Memory. (line 97) -* 'subreg' and '/s': Flags. (line 187) -* 'subreg' and '/u': Flags. (line 180) -* 'subreg' and '/u' and '/v': Flags. (line 170) -* 'subreg', in 'strict_low_part': RTL Declarations. (line 9) -* SUBREG_BYTE: Regs and Memory. (line 285) -* SUBREG_PROMOTED_UNSIGNED_P: Flags. (line 170) -* SUBREG_PROMOTED_UNSIGNED_SET: Flags. (line 180) -* SUBREG_PROMOTED_VAR_P: Flags. (line 187) -* SUBREG_REG: Regs and Memory. (line 285) -* subst iterators in '.md' files: Subst Iterators. (line 6) -* SUCCESS_EXIT_CODE: Host Misc. (line 12) -* SUPPORTS_INIT_PRIORITY: Macros for Initialization. - (line 57) -* SUPPORTS_ONE_ONLY: Label Output. (line 255) -* SUPPORTS_WEAK: Label Output. (line 229) -* SWITCHABLE_TARGET: Run-time Target. (line 164) -* SWITCH_BODY: Statements for C++. (line 6) -* SWITCH_COND: Statements for C++. (line 6) -* SWITCH_STMT: Statements for C++. (line 6) -* symbolic label: Sharing. (line 20) -* SYMBOL_FLAG_ANCHOR: Special Accessors. (line 117) -* SYMBOL_FLAG_EXTERNAL: Special Accessors. (line 99) -* SYMBOL_FLAG_FUNCTION: Special Accessors. (line 92) -* SYMBOL_FLAG_HAS_BLOCK_INFO: Special Accessors. (line 113) -* SYMBOL_FLAG_LOCAL: Special Accessors. (line 95) -* SYMBOL_FLAG_SMALL: Special Accessors. (line 104) -* SYMBOL_FLAG_TLS_SHIFT: Special Accessors. (line 108) -* symbol_ref: Constants. (line 86) -* 'symbol_ref' and '/f': Flags. (line 165) -* 'symbol_ref' and '/i': Flags. (line 202) -* 'symbol_ref' and '/u': Flags. (line 10) -* 'symbol_ref' and '/v': Flags. (line 206) -* 'symbol_ref', RTL sharing: Sharing. (line 20) -* SYMBOL_REF_ANCHOR_P: Special Accessors. (line 117) -* SYMBOL_REF_BLOCK: Special Accessors. (line 130) -* SYMBOL_REF_BLOCK_OFFSET: Special Accessors. (line 135) -* SYMBOL_REF_CONSTANT: Special Accessors. (line 78) -* SYMBOL_REF_DATA: Special Accessors. (line 82) -* SYMBOL_REF_DECL: Special Accessors. (line 67) -* SYMBOL_REF_EXTERNAL_P: Special Accessors. (line 99) -* SYMBOL_REF_FLAG: Flags. (line 206) -* 'SYMBOL_REF_FLAG', in 'TARGET_ENCODE_SECTION_INFO': Sections. - (line 277) -* SYMBOL_REF_FLAGS: Special Accessors. (line 86) -* SYMBOL_REF_FUNCTION_P: Special Accessors. (line 92) -* SYMBOL_REF_HAS_BLOCK_INFO_P: Special Accessors. (line 113) -* SYMBOL_REF_LOCAL_P: Special Accessors. (line 95) -* SYMBOL_REF_SMALL_P: Special Accessors. (line 104) -* SYMBOL_REF_TLS_MODEL: Special Accessors. (line 108) -* SYMBOL_REF_USED: Flags. (line 197) -* SYMBOL_REF_WEAK: Flags. (line 202) -* 'sync_addMODE' instruction pattern: Standard Names. (line 1635) -* 'sync_andMODE' instruction pattern: Standard Names. (line 1635) -* 'sync_compare_and_swapMODE' instruction pattern: Standard Names. - (line 1594) -* 'sync_iorMODE' instruction pattern: Standard Names. (line 1635) -* 'sync_lock_releaseMODE' instruction pattern: Standard Names. - (line 1704) -* 'sync_lock_test_and_setMODE' instruction pattern: Standard Names. - (line 1677) -* 'sync_nandMODE' instruction pattern: Standard Names. (line 1635) -* 'sync_new_addMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_new_andMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_new_iorMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_new_nandMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_new_subMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_new_xorMODE' instruction pattern: Standard Names. (line 1669) -* 'sync_old_addMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_old_andMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_old_iorMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_old_nandMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_old_subMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_old_xorMODE' instruction pattern: Standard Names. (line 1651) -* 'sync_subMODE' instruction pattern: Standard Names. (line 1635) -* 'sync_xorMODE' instruction pattern: Standard Names. (line 1635) -* SYSROOT_HEADERS_SUFFIX_SPEC: Driver. (line 176) -* SYSROOT_SUFFIX_SPEC: Driver. (line 171) -* 't-TARGET': Target Fragment. (line 6) -* table jump: Basic Blocks. (line 67) -* 'tablejump' instruction pattern: Standard Names. (line 1261) -* tag: GTY Options. (line 82) -* tagging insns: Tagging Insns. (line 6) -* tail calls: Tail Calls. (line 6) -* TAmode: Machine Modes. (line 158) -* target attributes: Target Attributes. (line 6) -* target description macros: Target Macros. (line 6) -* target functions: Target Structure. (line 6) -* target hooks: Target Structure. (line 6) -* target makefile fragment: Target Fragment. (line 6) -* target specifications: Run-time Target. (line 6) -* targetm: Target Structure. (line 6) -* targets, makefile: Makefile. (line 6) -* TARGET_ADDRESS_COST: Costs. (line 300) -* TARGET_ADDR_SPACE_ADDRESS_MODE: Named Address Spaces. - (line 43) -* TARGET_ADDR_SPACE_CONVERT: Named Address Spaces. - (line 85) -* TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P: Named Address Spaces. - (line 61) -* TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS: Named Address Spaces. - (line 69) -* TARGET_ADDR_SPACE_POINTER_MODE: Named Address Spaces. - (line 36) -* TARGET_ADDR_SPACE_SUBSET_P: Named Address Spaces. - (line 76) -* TARGET_ADDR_SPACE_VALID_POINTER_MODE: Named Address Spaces. - (line 50) -* TARGET_ALIGN_ANON_BITFIELD: Storage Layout. (line 397) -* TARGET_ALLOCATE_INITIAL_VALUE: Misc. (line 734) -* TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS: Misc. (line 1013) -* TARGET_ALWAYS_STRIP_DOTDOT: Driver. (line 246) -* TARGET_ARG_PARTIAL_BYTES: Register Arguments. (line 81) -* TARGET_ARM_EABI_UNWINDER: Exception Region Output. - (line 127) -* TARGET_ARRAY_MODE_SUPPORTED_P: Register Arguments. (line 333) -* TARGET_ASAN_SHADOW_OFFSET: Misc. (line 1041) -* TARGET_ASM_ALIGNED_DI_OP: Data Output. (line 9) -* TARGET_ASM_ALIGNED_HI_OP: Data Output. (line 7) -* TARGET_ASM_ALIGNED_SI_OP: Data Output. (line 8) -* TARGET_ASM_ALIGNED_TI_OP: Data Output. (line 10) -* TARGET_ASM_ASSEMBLE_VISIBILITY: Label Output. (line 266) -* TARGET_ASM_BYTE_OP: Data Output. (line 6) -* TARGET_ASM_CAN_OUTPUT_MI_THUNK: Function Entry. (line 202) -* TARGET_ASM_CLOSE_PAREN: Data Output. (line 129) -* TARGET_ASM_CODE_END: File Framework. (line 57) -* TARGET_ASM_CONSTRUCTOR: Macros for Initialization. - (line 68) -* TARGET_ASM_DECLARE_CONSTANT_NAME: Label Output. (line 149) -* TARGET_ASM_DESTRUCTOR: Macros for Initialization. - (line 82) -* TARGET_ASM_EMIT_EXCEPT_PERSONALITY: Dispatch Tables. (line 80) -* TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL: Dispatch Tables. (line 73) -* TARGET_ASM_EMIT_UNWIND_LABEL: Dispatch Tables. (line 61) -* TARGET_ASM_EXTERNAL_LIBCALL: Label Output. (line 302) -* TARGET_ASM_FILE_END: File Framework. (line 35) -* TARGET_ASM_FILE_START: File Framework. (line 8) -* TARGET_ASM_FILE_START_APP_OFF: File Framework. (line 16) -* TARGET_ASM_FILE_START_FILE_DIRECTIVE: File Framework. (line 29) -* TARGET_ASM_FINAL_POSTSCAN_INSN: Instruction Output. (line 82) -* TARGET_ASM_FUNCTION_BEGIN_EPILOGUE: Function Entry. (line 59) -* TARGET_ASM_FUNCTION_END_PROLOGUE: Function Entry. (line 53) -* TARGET_ASM_FUNCTION_EPILOGUE: Function Entry. (line 65) -* TARGET_ASM_FUNCTION_PROLOGUE: Function Entry. (line 9) -* TARGET_ASM_FUNCTION_RODATA_SECTION: Sections. (line 213) -* TARGET_ASM_FUNCTION_SECTION: File Framework. (line 121) -* TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS: File Framework. - (line 131) -* TARGET_ASM_GLOBALIZE_DECL_NAME: Label Output. (line 194) -* TARGET_ASM_GLOBALIZE_LABEL: Label Output. (line 185) -* TARGET_ASM_INIT_SECTIONS: Sections. (line 159) -* TARGET_ASM_INTEGER: Data Output. (line 25) -* TARGET_ASM_INTERNAL_LABEL: Label Output. (line 345) -* TARGET_ASM_JUMP_ALIGN_MAX_SKIP: Alignment Output. (line 21) -* TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP: Alignment Output. - (line 34) -* TARGET_ASM_LABEL_ALIGN_MAX_SKIP: Alignment Output. (line 68) -* TARGET_ASM_LOOP_ALIGN_MAX_SKIP: Alignment Output. (line 53) -* TARGET_ASM_LTO_END: File Framework. (line 52) -* TARGET_ASM_LTO_START: File Framework. (line 47) -* TARGET_ASM_MARK_DECL_PRESERVED: Label Output. (line 308) -* TARGET_ASM_MERGEABLE_RODATA_PREFIX: Sections. (line 221) -* TARGET_ASM_NAMED_SECTION: File Framework. (line 113) -* TARGET_ASM_OPEN_PAREN: Data Output. (line 128) -* TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA: Data Output. (line 38) -* TARGET_ASM_OUTPUT_ANCHOR: Anchored Addresses. (line 42) -* TARGET_ASM_OUTPUT_DWARF_DTPREL: SDB and DWARF. (line 99) -* TARGET_ASM_OUTPUT_IDENT: File Framework. (line 100) -* TARGET_ASM_OUTPUT_MI_THUNK: Function Entry. (line 160) -* TARGET_ASM_OUTPUT_SOURCE_FILENAME: File Framework. (line 91) -* TARGET_ASM_RECORD_GCC_SWITCHES: File Framework. (line 162) -* TARGET_ASM_RECORD_GCC_SWITCHES_SECTION: File Framework. (line 207) -* TARGET_ASM_RELOC_RW_MASK: Sections. (line 168) -* TARGET_ASM_SELECT_RTX_SECTION: Sections. (line 230) -* TARGET_ASM_SELECT_SECTION: Sections. (line 179) -* TARGET_ASM_TM_CLONE_TABLE_SECTION: Sections. (line 226) -* TARGET_ASM_TRAMPOLINE_TEMPLATE: Trampolines. (line 28) -* TARGET_ASM_TTYPE: Exception Region Output. - (line 121) -* TARGET_ASM_UNALIGNED_DI_OP: Data Output. (line 13) -* TARGET_ASM_UNALIGNED_HI_OP: Data Output. (line 11) -* TARGET_ASM_UNALIGNED_SI_OP: Data Output. (line 12) -* TARGET_ASM_UNALIGNED_TI_OP: Data Output. (line 14) -* TARGET_ASM_UNIQUE_SECTION: Sections. (line 201) -* TARGET_ASM_UNWIND_EMIT: Dispatch Tables. (line 87) -* TARGET_ASM_UNWIND_EMIT_BEFORE_INSN: Dispatch Tables. (line 92) -* TARGET_ATOMIC_ALIGN_FOR_MODE: Misc. (line 1060) -* TARGET_ATOMIC_ASSIGN_EXPAND_FENV: Misc. (line 1066) -* TARGET_ATOMIC_TEST_AND_SET_TRUEVAL: Misc. (line 1051) -* TARGET_ATTRIBUTE_TABLE: Target Attributes. (line 10) -* TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P: Target Attributes. (line 17) -* TARGET_BINDS_LOCAL_P: Sections. (line 308) -* TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED: Misc. (line 831) -* TARGET_BRANCH_TARGET_REGISTER_CLASS: Misc. (line 824) -* TARGET_BUILD_BUILTIN_VA_LIST: Register Arguments. (line 271) -* TARGET_BUILTIN_DECL: Misc. (line 603) -* TARGET_BUILTIN_RECIPROCAL: Addressing Modes. (line 261) -* TARGET_BUILTIN_SETJMP_FRAME_VALUE: Frame Layout. (line 107) -* TARGET_CALLEE_COPIES: Register Arguments. (line 113) -* TARGET_CANNOT_FORCE_CONST_MEM: Addressing Modes. (line 234) -* TARGET_CANNOT_MODIFY_JUMPS_P: Misc. (line 811) -* TARGET_CANONICALIZE_COMPARISON: MODE_CC Condition Codes. - (line 54) -* TARGET_CANONICAL_VA_LIST_TYPE: Register Arguments. (line 292) -* TARGET_CAN_ELIMINATE: Elimination. (line 73) -* TARGET_CAN_FOLLOW_JUMP: Misc. (line 720) -* TARGET_CAN_INLINE_P: Target Attributes. (line 159) -* TARGET_CAN_USE_DOLOOP_P: Misc. (line 675) -* TARGET_CASE_VALUES_THRESHOLD: Misc. (line 46) -* TARGET_CC_MODES_COMPATIBLE: MODE_CC Condition Codes. - (line 118) -* TARGET_CHECK_PCH_TARGET_FLAGS: PCH Target. (line 26) -* TARGET_CHECK_STRING_OBJECT_FORMAT_ARG: Run-time Target. (line 119) -* TARGET_CLASS_LIKELY_SPILLED_P: Register Classes. (line 489) -* TARGET_CLASS_MAX_NREGS: Register Classes. (line 505) -* TARGET_COMMUTATIVE_P: Misc. (line 727) -* TARGET_COMPARE_VERSION_PRIORITY: Misc. (line 652) -* TARGET_COMP_TYPE_ATTRIBUTES: Target Attributes. (line 25) -* TARGET_CONDITIONAL_REGISTER_USAGE: Register Basics. (line 59) -* TARGET_CONST_ANCHOR: Misc. (line 1024) -* TARGET_CONST_NOT_OK_FOR_DEBUG_P: Addressing Modes. (line 230) -* TARGET_CONVERT_TO_TYPE: Misc. (line 978) -* TARGET_CPU_CPP_BUILTINS: Run-time Target. (line 8) -* TARGET_CSTORE_MODE: Register Classes. (line 588) -* TARGET_CXX_ADJUST_CLASS_AT_DEFINITION: C++ ABI. (line 86) -* TARGET_CXX_CDTOR_RETURNS_THIS: C++ ABI. (line 37) -* TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT: C++ ABI. (line 61) -* TARGET_CXX_COOKIE_HAS_SIZE: C++ ABI. (line 24) -* TARGET_CXX_DECL_MANGLING_CONTEXT: C++ ABI. (line 92) -* TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY: C++ ABI. (line 52) -* TARGET_CXX_GET_COOKIE_SIZE: C++ ABI. (line 17) -* TARGET_CXX_GUARD_MASK_BIT: C++ ABI. (line 11) -* TARGET_CXX_GUARD_TYPE: C++ ABI. (line 6) -* TARGET_CXX_IMPLICIT_EXTERN_C: Misc. (line 373) -* TARGET_CXX_IMPORT_EXPORT_CLASS: C++ ABI. (line 28) -* TARGET_CXX_KEY_METHOD_MAY_BE_INLINE: C++ ABI. (line 42) -* TARGET_CXX_LIBRARY_RTTI_COMDAT: C++ ABI. (line 68) -* TARGET_CXX_USE_AEABI_ATEXIT: C++ ABI. (line 73) -* TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT: C++ ABI. (line 79) -* TARGET_C_PREINCLUDE: Misc. (line 361) -* TARGET_DEBUG_UNWIND_INFO: SDB and DWARF. (line 36) -* TARGET_DECIMAL_FLOAT_SUPPORTED_P: Storage Layout. (line 521) -* TARGET_DECLSPEC: Target Attributes. (line 72) -* TARGET_DEFAULT_PACK_STRUCT: Misc. (line 446) -* TARGET_DEFAULT_SHORT_ENUMS: Type Layout. (line 166) -* TARGET_DEFAULT_TARGET_FLAGS: Run-time Target. (line 55) -* TARGET_DEFERRED_OUTPUT_DEFS: Label Output. (line 430) -* TARGET_DELAY_SCHED2: SDB and DWARF. (line 65) -* TARGET_DELAY_VARTRACK: SDB and DWARF. (line 69) -* TARGET_DELEGITIMIZE_ADDRESS: Addressing Modes. (line 221) -* TARGET_DIFFERENT_ADDR_DISPLACEMENT_P: Register Classes. (line 574) -* TARGET_DLLIMPORT_DECL_ATTRIBUTES: Target Attributes. (line 55) -* TARGET_DWARF_CALLING_CONVENTION: SDB and DWARF. (line 16) -* TARGET_DWARF_HANDLE_FRAME_UNSPEC: Frame Layout. (line 169) -* TARGET_DWARF_REGISTER_SPAN: Exception Region Output. - (line 104) -* TARGET_EDOM: Library Calls. (line 59) -* TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS: Emulated TLS. (line 67) -* TARGET_EMUTLS_GET_ADDRESS: Emulated TLS. (line 18) -* TARGET_EMUTLS_REGISTER_COMMON: Emulated TLS. (line 23) -* TARGET_EMUTLS_TMPL_PREFIX: Emulated TLS. (line 44) -* TARGET_EMUTLS_TMPL_SECTION: Emulated TLS. (line 35) -* TARGET_EMUTLS_VAR_ALIGN_FIXED: Emulated TLS. (line 62) -* TARGET_EMUTLS_VAR_FIELDS: Emulated TLS. (line 48) -* TARGET_EMUTLS_VAR_INIT: Emulated TLS. (line 55) -* TARGET_EMUTLS_VAR_PREFIX: Emulated TLS. (line 40) -* TARGET_EMUTLS_VAR_SECTION: Emulated TLS. (line 30) -* TARGET_ENCODE_SECTION_INFO: Sections. (line 251) -* 'TARGET_ENCODE_SECTION_INFO' and address validation: Addressing Modes. - (line 82) -* 'TARGET_ENCODE_SECTION_INFO' usage: Instruction Output. (line 127) -* TARGET_ENUM_VA_LIST_P: Register Arguments. (line 275) -* TARGET_EXCEPT_UNWIND_INFO: Exception Region Output. - (line 45) -* TARGET_EXECUTABLE_SUFFIX: Misc. (line 785) -* TARGET_EXPAND_BUILTIN: Misc. (line 613) -* TARGET_EXPAND_BUILTIN_SAVEREGS: Varargs. (line 64) -* TARGET_EXPAND_TO_RTL_HOOK: Storage Layout. (line 527) -* TARGET_EXPR: Unary and Binary Expressions. - (line 6) -* TARGET_EXTRA_INCLUDES: Misc. (line 870) -* TARGET_EXTRA_LIVE_ON_ENTRY: Tail Calls. (line 20) -* TARGET_EXTRA_PRE_INCLUDES: Misc. (line 877) -* TARGET_FIXED_CONDITION_CODE_REGS: MODE_CC Condition Codes. - (line 103) -* TARGET_FIXED_POINT_SUPPORTED_P: Storage Layout. (line 524) -* target_flags: Run-time Target. (line 51) -* TARGET_FLAGS_REGNUM: Register Arguments. (line 391) -* TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P: Run-time Target. - (line 183) -* TARGET_FLT_EVAL_METHOD: Type Layout. (line 147) -* TARGET_FN_ABI_VA_LIST: Register Arguments. (line 287) -* TARGET_FOLD_BUILTIN: Misc. (line 635) -* TARGET_FORCE_AT_COMP_DIR: SDB and DWARF. (line 60) -* TARGET_FORMAT_TYPES: Misc. (line 898) -* TARGET_FRAME_POINTER_REQUIRED: Elimination. (line 8) -* TARGET_FUNCTION_ARG: Register Arguments. (line 10) -* TARGET_FUNCTION_ARG_ADVANCE: Register Arguments. (line 184) -* TARGET_FUNCTION_ARG_BOUNDARY: Register Arguments. (line 238) -* TARGET_FUNCTION_ARG_ROUND_BOUNDARY: Register Arguments. (line 244) -* TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P: Target Attributes. (line 93) -* TARGET_FUNCTION_INCOMING_ARG: Register Arguments. (line 65) -* TARGET_FUNCTION_OK_FOR_SIBCALL: Tail Calls. (line 6) -* TARGET_FUNCTION_VALUE: Scalar Return. (line 9) -* TARGET_FUNCTION_VALUE_REGNO_P: Scalar Return. (line 96) -* TARGET_GENERATE_VERSION_DISPATCHER_BODY: Misc. (line 668) -* TARGET_GET_DRAP_RTX: Misc. (line 1007) -* TARGET_GET_FUNCTION_VERSIONS_DISPATCHER: Misc. (line 661) -* TARGET_GET_PCH_VALIDITY: PCH Target. (line 6) -* TARGET_GET_RAW_ARG_MODE: Aggregate Return. (line 82) -* TARGET_GET_RAW_RESULT_MODE: Aggregate Return. (line 76) -* TARGET_GIMPLE_FOLD_BUILTIN: Misc. (line 645) -* TARGET_GIMPLIFY_VA_ARG_EXPR: Register Arguments. (line 297) -* TARGET_HANDLE_C_OPTION: Run-time Target. (line 73) -* TARGET_HANDLE_OPTION: Run-time Target. (line 59) -* TARGET_HARD_REGNO_SCRATCH_OK: Values in Registers. - (line 141) -* TARGET_HAS_IFUNC_P: Misc. (line 1055) -* TARGET_HAS_NO_HW_DIVIDE: Library Calls. (line 52) -* TARGET_HAVE_CONDITIONAL_EXECUTION: Misc. (line 845) -* TARGET_HAVE_CTORS_DTORS: Macros for Initialization. - (line 63) -* TARGET_HAVE_NAMED_SECTIONS: File Framework. (line 139) -* TARGET_HAVE_SRODATA_SECTION: Sections. (line 297) -* TARGET_HAVE_SWITCHABLE_BSS_SECTIONS: File Framework. (line 144) -* TARGET_HAVE_TLS: Sections. (line 317) -* TARGET_INIT_BUILTINS: Misc. (line 587) -* TARGET_INIT_DWARF_REG_SIZES_EXTRA: Exception Region Output. - (line 113) -* TARGET_INIT_LIBFUNCS: Library Calls. (line 15) -* TARGET_INSERT_ATTRIBUTES: Target Attributes. (line 80) -* TARGET_INSTANTIATE_DECLS: Storage Layout. (line 535) -* TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN: Misc. (line 931) -* TARGET_INVALID_BINARY_OP: Misc. (line 950) -* TARGET_INVALID_CONVERSION: Misc. (line 937) -* TARGET_INVALID_PARAMETER_TYPE: Misc. (line 956) -* TARGET_INVALID_RETURN_TYPE: Misc. (line 963) -* TARGET_INVALID_UNARY_OP: Misc. (line 943) -* TARGET_INVALID_WITHIN_DOLOOP: Misc. (line 692) -* TARGET_IN_SMALL_DATA_P: Sections. (line 293) -* TARGET_LEGITIMATE_ADDRESS_P: Addressing Modes. (line 48) -* TARGET_LEGITIMATE_COMBINED_INSN: Misc. (line 706) -* TARGET_LEGITIMATE_CONSTANT_P: Addressing Modes. (line 213) -* TARGET_LEGITIMIZE_ADDRESS: Addressing Modes. (line 129) -* TARGET_LIBCALL_VALUE: Scalar Return. (line 65) -* TARGET_LIBC_HAS_FUNCTION: Library Calls. (line 77) -* TARGET_LIBFUNC_GNU_PREFIX: Library Calls. (line 24) -* TARGET_LIBGCC_CMP_RETURN_MODE: Storage Layout. (line 458) -* TARGET_LIBGCC_SDATA_SECTION: Sections. (line 131) -* TARGET_LIBGCC_SHIFT_COUNT_MODE: Storage Layout. (line 464) -* TARGET_LIB_INT_CMP_BIASED: Library Calls. (line 42) -* TARGET_LOOP_UNROLL_ADJUST: Misc. (line 851) -* TARGET_LRA_P: Register Classes. (line 548) -* TARGET_MACHINE_DEPENDENT_REORG: Misc. (line 572) -* TARGET_MANGLE_ASSEMBLER_NAME: Label Output. (line 321) -* TARGET_MANGLE_DECL_ASSEMBLER_NAME: Sections. (line 241) -* TARGET_MANGLE_TYPE: Storage Layout. (line 539) -* TARGET_MAX_ANCHOR_OFFSET: Anchored Addresses. (line 38) -* TARGET_MD_ASM_CLOBBERS: Misc. (line 491) -* TARGET_MEMBER_TYPE_FORCES_BLK: Storage Layout. (line 410) -* TARGET_MEMMODEL_CHECK: Misc. (line 1046) -* TARGET_MEMORY_MOVE_COST: Costs. (line 79) -* TARGET_MEM_CONSTRAINT: Addressing Modes. (line 107) -* TARGET_MEM_REF: Storage References. (line 6) -* TARGET_MERGE_DECL_ATTRIBUTES: Target Attributes. (line 45) -* TARGET_MERGE_TYPE_ATTRIBUTES: Target Attributes. (line 37) -* TARGET_MIN_ANCHOR_OFFSET: Anchored Addresses. (line 32) -* TARGET_MIN_DIVISIONS_FOR_RECIP_MUL: Misc. (line 90) -* TARGET_MODE_DEPENDENT_ADDRESS_P: Addressing Modes. (line 196) -* TARGET_MODE_REP_EXTENDED: Misc. (line 175) -* TARGET_MS_BITFIELD_LAYOUT_P: Storage Layout. (line 493) -* TARGET_MUST_PASS_IN_STACK: Register Arguments. (line 58) -* 'TARGET_MUST_PASS_IN_STACK', and 'TARGET_FUNCTION_ARG': Register Arguments. - (line 50) -* TARGET_NARROW_VOLATILE_BITFIELD: Storage Layout. (line 403) -* TARGET_N_FORMAT_TYPES: Misc. (line 903) -* TARGET_OBJC_CONSTRUCT_STRING_OBJECT: Run-time Target. (line 88) -* TARGET_OBJC_DECLARE_CLASS_DEFINITION: Run-time Target. (line 109) -* TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE: Run-time Target. - (line 104) -* TARGET_OBJECT_SUFFIX: Misc. (line 780) -* TARGET_OBJFMT_CPP_BUILTINS: Run-time Target. (line 45) -* TARGET_OPTF: Misc. (line 885) -* TARGET_OPTION_DEFAULT_PARAMS: Run-time Target. (line 160) -* TARGET_OPTION_FUNCTION_VERSIONS: Target Attributes. (line 151) -* TARGET_OPTION_INIT_STRUCT: Run-time Target. (line 156) -* TARGET_OPTION_OPTIMIZATION_TABLE: Run-time Target. (line 142) -* TARGET_OPTION_OVERRIDE: Target Attributes. (line 138) -* TARGET_OPTION_PRAGMA_PARSE: Target Attributes. (line 131) -* TARGET_OPTION_PRINT: Target Attributes. (line 125) -* TARGET_OPTION_RESTORE: Target Attributes. (line 119) -* TARGET_OPTION_SAVE: Target Attributes. (line 112) -* TARGET_OPTION_VALID_ATTRIBUTE_P: Target Attributes. (line 100) -* TARGET_OS_CPP_BUILTINS: Run-time Target. (line 41) -* TARGET_OVERRIDES_FORMAT_ATTRIBUTES: Misc. (line 907) -* TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT: Misc. (line 913) -* TARGET_OVERRIDES_FORMAT_INIT: Misc. (line 917) -* TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE: Run-time Target. (line 126) -* TARGET_PASS_BY_REFERENCE: Register Arguments. (line 101) -* TARGET_PCH_VALID_P: PCH Target. (line 11) -* TARGET_POSIX_IO: Misc. (line 516) -* TARGET_PREFERRED_OUTPUT_RELOAD_CLASS: Register Classes. (line 284) -* TARGET_PREFERRED_RELOAD_CLASS: Register Classes. (line 213) -* TARGET_PREFERRED_RENAME_CLASS: Register Classes. (line 201) -* TARGET_PREPARE_PCH_SAVE: PCH Target. (line 34) -* TARGET_PRETEND_OUTGOING_VARARGS_NAMED: Varargs. (line 123) -* TARGET_PROFILE_BEFORE_PROLOGUE: Sections. (line 301) -* TARGET_PROMOTED_TYPE: Misc. (line 970) -* TARGET_PROMOTE_FUNCTION_MODE: Storage Layout. (line 109) -* TARGET_PROMOTE_PROTOTYPES: Stack Arguments. (line 10) -* TARGET_PTRMEMFUNC_VBIT_LOCATION: Type Layout. (line 293) -* TARGET_REF_MAY_ALIAS_ERRNO: Register Arguments. (line 308) -* TARGET_REGISTER_MOVE_COST: Costs. (line 31) -* TARGET_REGISTER_PRIORITY: Register Classes. (line 553) -* TARGET_REGISTER_USAGE_LEVELING_P: Register Classes. (line 564) -* TARGET_RELAXED_ORDERING: Misc. (line 922) -* TARGET_RESOLVE_OVERLOADED_BUILTIN: Misc. (line 624) -* TARGET_RETURN_IN_MEMORY: Aggregate Return. (line 15) -* TARGET_RETURN_IN_MSB: Scalar Return. (line 117) -* TARGET_RETURN_POPS_ARGS: Stack Arguments. (line 92) -* TARGET_RTX_COSTS: Costs. (line 269) -* TARGET_SCALAR_MODE_SUPPORTED_P: Register Arguments. (line 315) -* TARGET_SCHED_ADJUST_COST: Scheduling. (line 35) -* TARGET_SCHED_ADJUST_PRIORITY: Scheduling. (line 50) -* TARGET_SCHED_ALLOC_SCHED_CONTEXT: Scheduling. (line 283) -* TARGET_SCHED_CLEAR_SCHED_CONTEXT: Scheduling. (line 298) -* TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK: Scheduling. (line 98) -* TARGET_SCHED_DFA_NEW_CYCLE: Scheduling. (line 245) -* TARGET_SCHED_DFA_POST_ADVANCE_CYCLE: Scheduling. (line 169) -* TARGET_SCHED_DFA_POST_CYCLE_INSN: Scheduling. (line 153) -* TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE: Scheduling. (line 162) -* TARGET_SCHED_DFA_PRE_CYCLE_INSN: Scheduling. (line 141) -* TARGET_SCHED_DISPATCH: Scheduling. (line 365) -* TARGET_SCHED_DISPATCH_DO: Scheduling. (line 370) -* TARGET_SCHED_EXPOSED_PIPELINE: Scheduling. (line 374) -* TARGET_SCHED_FINISH: Scheduling. (line 119) -* TARGET_SCHED_FINISH_GLOBAL: Scheduling. (line 134) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK: Scheduling. (line 225) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN: Scheduling. (line 214) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD: Scheduling. - (line 176) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD: Scheduling. - (line 204) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC: Scheduling. - (line 336) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END: Scheduling. (line 230) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI: Scheduling. (line 240) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT: Scheduling. (line 235) -* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE: Scheduling. (line 219) -* TARGET_SCHED_FREE_SCHED_CONTEXT: Scheduling. (line 302) -* TARGET_SCHED_GEN_SPEC_CHECK: Scheduling. (line 324) -* TARGET_SCHED_H_I_D_EXTENDED: Scheduling. (line 278) -* TARGET_SCHED_INIT: Scheduling. (line 108) -* TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN: Scheduling. (line 158) -* TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN: Scheduling. (line 150) -* TARGET_SCHED_INIT_GLOBAL: Scheduling. (line 126) -* TARGET_SCHED_INIT_SCHED_CONTEXT: Scheduling. (line 287) -* TARGET_SCHED_ISSUE_RATE: Scheduling. (line 11) -* TARGET_SCHED_IS_COSTLY_DEPENDENCE: Scheduling. (line 256) -* TARGET_SCHED_MACRO_FUSION_P: Scheduling. (line 87) -* TARGET_SCHED_MACRO_FUSION_PAIR_P: Scheduling. (line 91) -* TARGET_SCHED_NEEDS_BLOCK_P: Scheduling. (line 317) -* TARGET_SCHED_REASSOCIATION_WIDTH: Scheduling. (line 379) -* TARGET_SCHED_REORDER: Scheduling. (line 58) -* TARGET_SCHED_REORDER2: Scheduling. (line 75) -* TARGET_SCHED_SET_SCHED_CONTEXT: Scheduling. (line 294) -* TARGET_SCHED_SET_SCHED_FLAGS: Scheduling. (line 349) -* TARGET_SCHED_SMS_RES_MII: Scheduling. (line 356) -* TARGET_SCHED_SPECULATE_INSN: Scheduling. (line 305) -* TARGET_SCHED_VARIABLE_ISSUE: Scheduling. (line 22) -* TARGET_SECONDARY_RELOAD: Register Classes. (line 312) -* TARGET_SECTION_TYPE_FLAGS: File Framework. (line 149) -* TARGET_SETUP_INCOMING_VARARGS: Varargs. (line 71) -* TARGET_SET_CURRENT_FUNCTION: Misc. (line 762) -* TARGET_SET_DEFAULT_TYPE_ATTRIBUTES: Target Attributes. (line 33) -* TARGET_SET_UP_BY_PROLOGUE: Tail Calls. (line 29) -* TARGET_SHIFT_TRUNCATION_MASK: Misc. (line 138) -* TARGET_SIMD_CLONE_ADJUST: Addressing Modes. (line 413) -* TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN: Addressing Modes. - (line 405) -* TARGET_SIMD_CLONE_USABLE: Addressing Modes. (line 417) -* TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P: Register Arguments. - (line 357) -* TARGET_SPILL_CLASS: Register Classes. (line 581) -* TARGET_SPLIT_COMPLEX_ARG: Register Arguments. (line 259) -* TARGET_STACK_PROTECT_FAIL: Stack Smashing Protection. - (line 16) -* TARGET_STACK_PROTECT_GUARD: Stack Smashing Protection. - (line 6) -* TARGET_STATIC_CHAIN: Frame Registers. (line 90) -* TARGET_STRICT_ARGUMENT_NAMING: Varargs. (line 107) -* TARGET_STRING_OBJECT_REF_TYPE_P: Run-time Target. (line 114) -* TARGET_STRIP_NAME_ENCODING: Sections. (line 288) -* TARGET_STRUCT_VALUE_RTX: Aggregate Return. (line 44) -* TARGET_SUPPORTS_SPLIT_STACK: Stack Smashing Protection. - (line 25) -* TARGET_SUPPORTS_WEAK: Label Output. (line 237) -* TARGET_TERMINATE_DW2_EH_FRAME_INFO: Exception Region Output. - (line 98) -* TARGET_TRAMPOLINE_ADJUST_ADDRESS: Trampolines. (line 74) -* TARGET_TRAMPOLINE_INIT: Trampolines. (line 54) -* TARGET_UNSPEC_MAY_TRAP_P: Misc. (line 753) -* TARGET_UNWIND_TABLES_DEFAULT: Exception Region Output. - (line 72) -* TARGET_UNWIND_WORD_MODE: Storage Layout. (line 470) -* TARGET_UPDATE_STACK_BOUNDARY: Misc. (line 1003) -* TARGET_USES_WEAK_UNWIND_INFO: Exception Handling. (line 123) -* TARGET_USE_ANCHORS_FOR_SYMBOL_P: Anchored Addresses. (line 53) -* TARGET_USE_BLOCKS_FOR_CONSTANT_P: Addressing Modes. (line 248) -* TARGET_USE_BLOCKS_FOR_DECL_P: Addressing Modes. (line 255) -* TARGET_USE_JCR_SECTION: Misc. (line 985) -* TARGET_VALID_DLLIMPORT_ATTRIBUTE_P: Target Attributes. (line 66) -* TARGET_VALID_POINTER_MODE: Register Arguments. (line 303) -* TARGET_VECTORIZE_ADD_STMT_COST: Addressing Modes. (line 367) -* TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES: Addressing Modes. - (line 350) -* TARGET_VECTORIZE_BUILTIN_CONVERSION: Addressing Modes. (line 312) -* TARGET_VECTORIZE_BUILTIN_GATHER: Addressing Modes. (line 398) -* TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD: Addressing Modes. (line 271) -* TARGET_VECTORIZE_BUILTIN_TM_LOAD: Addressing Modes. (line 390) -* TARGET_VECTORIZE_BUILTIN_TM_STORE: Addressing Modes. (line 394) -* TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST: Addressing Modes. - (line 297) -* TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION: Addressing Modes. - (line 324) -* TARGET_VECTORIZE_DESTROY_COST_DATA: Addressing Modes. (line 385) -* TARGET_VECTORIZE_FINISH_COST: Addressing Modes. (line 378) -* TARGET_VECTORIZE_INIT_COST: Addressing Modes. (line 358) -* TARGET_VECTORIZE_PREFERRED_SIMD_MODE: Addressing Modes. (line 343) -* TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT: Addressing Modes. - (line 333) -* TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE: Addressing Modes. - (line 303) -* TARGET_VECTORIZE_VEC_PERM_CONST_OK: Addressing Modes. (line 308) -* TARGET_VECTOR_ALIGNMENT: Storage Layout. (line 263) -* TARGET_VECTOR_MODE_SUPPORTED_P: Register Arguments. (line 327) -* TARGET_VTABLE_DATA_ENTRY_DISTANCE: Type Layout. (line 346) -* TARGET_VTABLE_ENTRY_ALIGN: Type Layout. (line 340) -* TARGET_VTABLE_USES_DESCRIPTORS: Type Layout. (line 329) -* TARGET_WANT_DEBUG_PUB_SECTIONS: SDB and DWARF. (line 55) -* TARGET_WARN_FUNC_RETURN: Tail Calls. (line 35) -* TARGET_WEAK_NOT_IN_ARCHIVE_TOC: Label Output. (line 273) -* TCmode: Machine Modes. (line 199) -* TDmode: Machine Modes. (line 97) -* TEMPLATE_DECL: Declarations. (line 6) -* Temporaries: Temporaries. (line 6) -* termination routines: Initialization. (line 6) -* testing constraints: C Constraint Interface. - (line 6) -* TEXT_SECTION_ASM_OP: Sections. (line 37) -* TFmode: Machine Modes. (line 101) -* TF_SIZE: Type Layout. (line 138) -* THEN_CLAUSE: Statements for C++. (line 6) -* THREAD_MODEL_SPEC: Driver. (line 162) -* THROW_EXPR: Unary and Binary Expressions. - (line 6) -* THUNK_DECL: Declarations. (line 6) -* THUNK_DELTA: Declarations. (line 6) -* TImode: Machine Modes. (line 48) -* 'TImode', in 'insn': Insns. (line 268) -* TLS_COMMON_ASM_OP: Sections. (line 80) -* TLS_SECTION_ASM_FLAG: Sections. (line 85) -* 'tm.h' macros: Target Macros. (line 6) -* TQFmode: Machine Modes. (line 65) -* TQmode: Machine Modes. (line 122) -* trampolines for nested functions: Trampolines. (line 6) -* TRAMPOLINE_ALIGNMENT: Trampolines. (line 48) -* TRAMPOLINE_SECTION: Trampolines. (line 39) -* TRAMPOLINE_SIZE: Trampolines. (line 44) -* TRANSFER_FROM_TRAMPOLINE: Trampolines. (line 110) -* 'trap' instruction pattern: Standard Names. (line 1542) -* tree: Tree overview. (line 6) -* tree <1>: Macros and Functions. - (line 6) -* Tree SSA: Tree SSA. (line 6) -* TREE_CHAIN: Macros and Functions. - (line 6) -* TREE_CODE: Tree overview. (line 6) -* tree_int_cst_equal: Constant expressions. - (line 6) -* TREE_INT_CST_HIGH: Constant expressions. - (line 6) -* TREE_INT_CST_LOW: Constant expressions. - (line 6) -* tree_int_cst_lt: Constant expressions. - (line 6) -* TREE_LIST: Containers. (line 6) -* TREE_OPERAND: Expression trees. (line 6) -* TREE_PUBLIC: Function Basics. (line 6) -* TREE_PUBLIC <1>: Function Properties. - (line 28) -* TREE_PURPOSE: Containers. (line 6) -* TREE_READONLY: Function Properties. - (line 37) -* tree_size: Macros and Functions. - (line 13) -* TREE_STATIC: Function Properties. - (line 31) -* TREE_STRING_LENGTH: Constant expressions. - (line 6) -* TREE_STRING_POINTER: Constant expressions. - (line 6) -* TREE_THIS_VOLATILE: Function Properties. - (line 34) -* TREE_TYPE: Macros and Functions. - (line 6) -* TREE_TYPE <1>: Types. (line 6) -* TREE_TYPE <2>: Working with declarations. - (line 11) -* TREE_TYPE <3>: Expression trees. (line 6) -* TREE_TYPE <4>: Expression trees. (line 17) -* TREE_TYPE <5>: Function Basics. (line 47) -* TREE_TYPE <6>: Types for C++. (line 6) -* TREE_VALUE: Containers. (line 6) -* TREE_VEC: Containers. (line 6) -* TREE_VEC_ELT: Containers. (line 6) -* TREE_VEC_LENGTH: Containers. (line 6) -* TRULY_NOOP_TRUNCATION: Misc. (line 162) -* truncate: Conversions. (line 38) -* 'truncMN2' instruction pattern: Standard Names. (line 916) -* TRUNC_DIV_EXPR: Unary and Binary Expressions. - (line 6) -* TRUNC_MOD_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_ANDIF_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_AND_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_NOT_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_ORIF_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_OR_EXPR: Unary and Binary Expressions. - (line 6) -* TRUTH_XOR_EXPR: Unary and Binary Expressions. - (line 6) -* TRY_BLOCK: Statements for C++. (line 6) -* TRY_HANDLERS: Statements for C++. (line 6) -* TRY_STMTS: Statements for C++. (line 6) -* Tuple specific accessors: Tuple specific accessors. - (line 6) -* tuples: Tuple representation. - (line 6) -* type: Types. (line 6) -* type declaration: Declarations. (line 6) -* TYPENAME_TYPE: Types for C++. (line 6) -* TYPENAME_TYPE_FULLNAME: Types. (line 6) -* TYPENAME_TYPE_FULLNAME <1>: Types for C++. (line 6) -* TYPEOF_TYPE: Types for C++. (line 6) -* TYPE_ALIGN: Types. (line 6) -* TYPE_ALIGN <1>: Types. (line 30) -* TYPE_ALIGN <2>: Types for C++. (line 6) -* TYPE_ALIGN <3>: Types for C++. (line 44) -* TYPE_ARG_TYPES: Types. (line 6) -* TYPE_ARG_TYPES <1>: Types for C++. (line 6) -* TYPE_ASM_OP: Label Output. (line 76) -* TYPE_ATTRIBUTES: Attributes. (line 24) -* TYPE_BINFO: Classes. (line 6) -* TYPE_BUILT_IN: Types for C++. (line 66) -* TYPE_CANONICAL: Types. (line 6) -* TYPE_CANONICAL <1>: Types. (line 41) -* TYPE_CONTEXT: Types. (line 6) -* TYPE_CONTEXT <1>: Types for C++. (line 6) -* TYPE_DECL: Declarations. (line 6) -* TYPE_FIELDS: Types. (line 6) -* TYPE_FIELDS <1>: Types for C++. (line 6) -* TYPE_FIELDS <2>: Classes. (line 6) -* TYPE_HAS_ARRAY_NEW_OPERATOR: Classes. (line 96) -* TYPE_HAS_DEFAULT_CONSTRUCTOR: Classes. (line 81) -* TYPE_HAS_MUTABLE_P: Classes. (line 86) -* TYPE_HAS_NEW_OPERATOR: Classes. (line 93) -* TYPE_MAIN_VARIANT: Types. (line 6) -* TYPE_MAIN_VARIANT <1>: Types. (line 19) -* TYPE_MAIN_VARIANT <2>: Types for C++. (line 6) -* TYPE_MAX_VALUE: Types. (line 6) -* TYPE_METHODS: Classes. (line 6) -* TYPE_METHOD_BASETYPE: Types. (line 6) -* TYPE_METHOD_BASETYPE <1>: Types for C++. (line 6) -* TYPE_MIN_VALUE: Types. (line 6) -* TYPE_NAME: Types. (line 6) -* TYPE_NAME <1>: Types. (line 33) -* TYPE_NAME <2>: Types for C++. (line 6) -* TYPE_NAME <3>: Types for C++. (line 47) -* TYPE_NOTHROW_P: Functions for C++. (line 154) -* TYPE_OFFSET_BASETYPE: Types. (line 6) -* TYPE_OFFSET_BASETYPE <1>: Types for C++. (line 6) -* TYPE_OPERAND_FMT: Label Output. (line 87) -* TYPE_OVERLOADS_ARRAY_REF: Classes. (line 104) -* TYPE_OVERLOADS_ARROW: Classes. (line 107) -* TYPE_OVERLOADS_CALL_EXPR: Classes. (line 100) -* TYPE_POLYMORPHIC_P: Classes. (line 77) -* TYPE_PRECISION: Types. (line 6) -* TYPE_PRECISION <1>: Types for C++. (line 6) -* TYPE_PTRDATAMEM_P: Types for C++. (line 6) -* TYPE_PTRDATAMEM_P <1>: Types for C++. (line 69) -* TYPE_PTRFN_P: Types for C++. (line 76) -* TYPE_PTROBV_P: Types for C++. (line 6) -* TYPE_PTROB_P: Types for C++. (line 79) -* TYPE_PTR_P: Types for C++. (line 72) -* TYPE_QUAL_CONST: Types. (line 6) -* TYPE_QUAL_CONST <1>: Types for C++. (line 6) -* TYPE_QUAL_RESTRICT: Types. (line 6) -* TYPE_QUAL_RESTRICT <1>: Types for C++. (line 6) -* TYPE_QUAL_VOLATILE: Types. (line 6) -* TYPE_QUAL_VOLATILE <1>: Types for C++. (line 6) -* TYPE_RAISES_EXCEPTIONS: Functions for C++. (line 149) -* TYPE_SIZE: Types. (line 6) -* TYPE_SIZE <1>: Types. (line 25) -* TYPE_SIZE <2>: Types for C++. (line 6) -* TYPE_SIZE <3>: Types for C++. (line 39) -* TYPE_STRUCTURAL_EQUALITY_P: Types. (line 6) -* TYPE_STRUCTURAL_EQUALITY_P <1>: Types. (line 77) -* TYPE_UNQUALIFIED: Types. (line 6) -* TYPE_UNQUALIFIED <1>: Types for C++. (line 6) -* TYPE_VFIELD: Classes. (line 6) -* UDAmode: Machine Modes. (line 170) -* udiv: Arithmetic. (line 131) -* 'udivM3' instruction pattern: Standard Names. (line 276) -* 'udivmodM4' instruction pattern: Standard Names. (line 513) -* 'udot_prodM' instruction pattern: Standard Names. (line 342) -* UDQmode: Machine Modes. (line 138) -* UHAmode: Machine Modes. (line 162) -* UHQmode: Machine Modes. (line 130) -* UINT16_TYPE: Type Layout. (line 257) -* UINT32_TYPE: Type Layout. (line 258) -* UINT64_TYPE: Type Layout. (line 259) -* UINT8_TYPE: Type Layout. (line 256) -* UINTMAX_TYPE: Type Layout. (line 240) -* UINTPTR_TYPE: Type Layout. (line 277) -* UINT_FAST16_TYPE: Type Layout. (line 273) -* UINT_FAST32_TYPE: Type Layout. (line 274) -* UINT_FAST64_TYPE: Type Layout. (line 275) -* UINT_FAST8_TYPE: Type Layout. (line 272) -* UINT_LEAST16_TYPE: Type Layout. (line 265) -* UINT_LEAST32_TYPE: Type Layout. (line 266) -* UINT_LEAST64_TYPE: Type Layout. (line 267) -* UINT_LEAST8_TYPE: Type Layout. (line 264) -* 'umaddMN4' instruction pattern: Standard Names. (line 460) -* umax: Arithmetic. (line 150) -* 'umaxM3' instruction pattern: Standard Names. (line 276) -* umin: Arithmetic. (line 150) -* 'uminM3' instruction pattern: Standard Names. (line 276) -* umod: Arithmetic. (line 137) -* 'umodM3' instruction pattern: Standard Names. (line 276) -* 'umsubMN4' instruction pattern: Standard Names. (line 484) -* 'umulhisi3' instruction pattern: Standard Names. (line 432) -* 'umulM3_highpart' instruction pattern: Standard Names. (line 446) -* 'umulqihi3' instruction pattern: Standard Names. (line 432) -* 'umulsidi3' instruction pattern: Standard Names. (line 432) -* unchanging: Flags. (line 296) -* 'unchanging', in 'call_insn': Flags. (line 19) -* 'unchanging', in 'jump_insn', 'call_insn' and 'insn': Flags. - (line 39) -* 'unchanging', in 'mem': Flags. (line 134) -* 'unchanging', in 'subreg': Flags. (line 170) -* 'unchanging', in 'subreg' <1>: Flags. (line 180) -* 'unchanging', in 'symbol_ref': Flags. (line 10) -* UNEQ_EXPR: Unary and Binary Expressions. - (line 6) -* UNGE_EXPR: Unary and Binary Expressions. - (line 6) -* UNGT_EXPR: Unary and Binary Expressions. - (line 6) -* unions, returning: Interface. (line 10) -* UNION_TYPE: Types. (line 6) -* UNION_TYPE <1>: Classes. (line 6) -* UNITS_PER_WORD: Storage Layout. (line 60) -* UNKNOWN_TYPE: Types. (line 6) -* UNKNOWN_TYPE <1>: Types for C++. (line 6) -* UNLE_EXPR: Unary and Binary Expressions. - (line 6) -* UNLIKELY_EXECUTED_TEXT_SECTION_NAME: Sections. (line 48) -* UNLT_EXPR: Unary and Binary Expressions. - (line 6) -* UNORDERED_EXPR: Unary and Binary Expressions. - (line 6) -* unshare_all_rtl: Sharing. (line 58) -* unsigned division: Arithmetic. (line 131) -* unsigned division with unsigned saturation: Arithmetic. (line 131) -* unsigned greater than: Comparisons. (line 64) -* unsigned greater than <1>: Comparisons. (line 72) -* unsigned less than: Comparisons. (line 68) -* unsigned less than <1>: Comparisons. (line 76) -* unsigned minimum and maximum: Arithmetic. (line 150) -* unsigned_fix: Conversions. (line 77) -* unsigned_float: Conversions. (line 62) -* unsigned_fract_convert: Conversions. (line 97) -* unsigned_sat_fract: Conversions. (line 103) -* unspec: Side Effects. (line 298) -* unspec <1>: Constant Definitions. - (line 111) -* unspec_volatile: Side Effects. (line 298) -* unspec_volatile <1>: Constant Definitions. - (line 99) -* 'untyped_call' instruction pattern: Standard Names. (line 1158) -* 'untyped_return' instruction pattern: Standard Names. (line 1221) -* UPDATE_PATH_HOST_CANONICALIZE (PATH): Filesystem. (line 59) -* update_ssa: SSA. (line 74) -* update_stmt: Manipulating GIMPLE statements. - (line 140) -* update_stmt <1>: SSA Operands. (line 6) -* update_stmt_if_modified: Manipulating GIMPLE statements. - (line 143) -* UQQmode: Machine Modes. (line 126) -* 'usaddM3' instruction pattern: Standard Names. (line 276) -* USAmode: Machine Modes. (line 166) -* 'usashlM3' instruction pattern: Standard Names. (line 516) -* 'usdivM3' instruction pattern: Standard Names. (line 276) -* use: Side Effects. (line 168) -* used: Flags. (line 314) -* 'used', in 'symbol_ref': Flags. (line 197) -* user: GTY Options. (line 318) -* user gc: User GC. (line 6) -* USER_LABEL_PREFIX: Instruction Output. (line 152) -* USE_C_ALLOCA: Host Misc. (line 19) -* USE_LD_AS_NEEDED: Driver. (line 135) -* USE_LOAD_POST_DECREMENT: Costs. (line 225) -* USE_LOAD_POST_INCREMENT: Costs. (line 220) -* USE_LOAD_PRE_DECREMENT: Costs. (line 235) -* USE_LOAD_PRE_INCREMENT: Costs. (line 230) -* use_param: GTY Options. (line 119) -* use_paramN: GTY Options. (line 138) -* use_params: GTY Options. (line 147) -* USE_SELECT_SECTION_FOR_FUNCTIONS: Sections. (line 193) -* USE_STORE_POST_DECREMENT: Costs. (line 245) -* USE_STORE_POST_INCREMENT: Costs. (line 240) -* USE_STORE_PRE_DECREMENT: Costs. (line 255) -* USE_STORE_PRE_INCREMENT: Costs. (line 250) -* USING_STMT: Statements for C++. (line 6) -* 'usmaddMN4' instruction pattern: Standard Names. (line 468) -* 'usmsubMN4' instruction pattern: Standard Names. (line 492) -* 'usmulhisi3' instruction pattern: Standard Names. (line 436) -* 'usmulM3' instruction pattern: Standard Names. (line 276) -* 'usmulqihi3' instruction pattern: Standard Names. (line 436) -* 'usmulsidi3' instruction pattern: Standard Names. (line 436) -* 'usnegM2' instruction pattern: Standard Names. (line 538) -* USQmode: Machine Modes. (line 134) -* 'ussubM3' instruction pattern: Standard Names. (line 276) -* 'usum_widenM3' instruction pattern: Standard Names. (line 351) -* us_ashift: Arithmetic. (line 174) -* us_minus: Arithmetic. (line 38) -* us_mult: Arithmetic. (line 93) -* us_neg: Arithmetic. (line 82) -* us_plus: Arithmetic. (line 14) -* us_truncate: Conversions. (line 48) -* UTAmode: Machine Modes. (line 174) -* UTQmode: Machine Modes. (line 142) -* 'V' in constraint: Simple Constraints. (line 43) -* values, returned by functions: Scalar Return. (line 6) -* varargs implementation: Varargs. (line 6) -* variable: Declarations. (line 6) -* Variable Location Debug Information in RTL: Debug Information. - (line 6) -* variable_size: GTY Options. (line 245) -* VAR_DECL: Declarations. (line 6) -* var_location: Debug Information. (line 14) -* 'vashlM3' instruction pattern: Standard Names. (line 530) -* 'vashrM3' instruction pattern: Standard Names. (line 530) -* VA_ARG_EXPR: Unary and Binary Expressions. - (line 6) -* 'vcondMN' instruction pattern: Standard Names. (line 213) -* vector: Containers. (line 6) -* vector operations: Vector Operations. (line 6) -* VECTOR_CST: Constant expressions. - (line 6) -* VECTOR_STORE_FLAG_VALUE: Misc. (line 293) -* vec_concat: Vector Operations. (line 28) -* vec_duplicate: Vector Operations. (line 33) -* 'vec_extractM' instruction pattern: Standard Names. (line 203) -* 'vec_initM' instruction pattern: Standard Names. (line 208) -* 'vec_load_lanesMN' instruction pattern: Standard Names. (line 165) -* VEC_LSHIFT_EXPR: Vectors. (line 6) -* vec_merge: Vector Operations. (line 11) -* VEC_PACK_FIX_TRUNC_EXPR: Vectors. (line 6) -* VEC_PACK_SAT_EXPR: Vectors. (line 6) -* 'vec_pack_sfix_trunc_M' instruction pattern: Standard Names. - (line 377) -* 'vec_pack_ssat_M' instruction pattern: Standard Names. (line 370) -* VEC_PACK_TRUNC_EXPR: Vectors. (line 6) -* 'vec_pack_trunc_M' instruction pattern: Standard Names. (line 363) -* 'vec_pack_ufix_trunc_M' instruction pattern: Standard Names. - (line 377) -* 'vec_pack_usat_M' instruction pattern: Standard Names. (line 370) -* 'vec_permM' instruction pattern: Standard Names. (line 223) -* 'vec_perm_constM' instruction pattern: Standard Names. (line 239) -* VEC_RSHIFT_EXPR: Vectors. (line 6) -* vec_select: Vector Operations. (line 19) -* 'vec_setM' instruction pattern: Standard Names. (line 198) -* 'vec_shl_M' instruction pattern: Standard Names. (line 357) -* 'vec_shr_M' instruction pattern: Standard Names. (line 357) -* 'vec_store_lanesMN' instruction pattern: Standard Names. (line 187) -* 'vec_unpacks_float_hi_M' instruction pattern: Standard Names. - (line 398) -* 'vec_unpacks_float_lo_M' instruction pattern: Standard Names. - (line 398) -* 'vec_unpacks_hi_M' instruction pattern: Standard Names. (line 384) -* 'vec_unpacks_lo_M' instruction pattern: Standard Names. (line 384) -* 'vec_unpacku_float_hi_M' instruction pattern: Standard Names. - (line 398) -* 'vec_unpacku_float_lo_M' instruction pattern: Standard Names. - (line 398) -* 'vec_unpacku_hi_M' instruction pattern: Standard Names. (line 391) -* 'vec_unpacku_lo_M' instruction pattern: Standard Names. (line 391) -* VEC_UNPACK_FLOAT_HI_EXPR: Vectors. (line 6) -* VEC_UNPACK_FLOAT_LO_EXPR: Vectors. (line 6) -* VEC_UNPACK_HI_EXPR: Vectors. (line 6) -* VEC_UNPACK_LO_EXPR: Vectors. (line 6) -* VEC_WIDEN_MULT_HI_EXPR: Vectors. (line 6) -* VEC_WIDEN_MULT_LO_EXPR: Vectors. (line 6) -* 'vec_widen_smult_even_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_smult_hi_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_smult_lo_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_smult_odd_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_sshiftl_hi_M' instruction pattern: Standard Names. - (line 418) -* 'vec_widen_sshiftl_lo_M' instruction pattern: Standard Names. - (line 418) -* 'vec_widen_umult_even_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_umult_hi_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_umult_lo_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_umult_odd_M' instruction pattern: Standard Names. - (line 407) -* 'vec_widen_ushiftl_hi_M' instruction pattern: Standard Names. - (line 418) -* 'vec_widen_ushiftl_lo_M' instruction pattern: Standard Names. - (line 418) -* verify_flow_info: Maintaining the CFG. - (line 117) -* virtual operands: SSA Operands. (line 6) -* VIRTUAL_INCOMING_ARGS_REGNUM: Regs and Memory. (line 59) -* VIRTUAL_OUTGOING_ARGS_REGNUM: Regs and Memory. (line 87) -* VIRTUAL_STACK_DYNAMIC_REGNUM: Regs and Memory. (line 78) -* VIRTUAL_STACK_VARS_REGNUM: Regs and Memory. (line 69) -* VLIW: Processor pipeline description. - (line 6) -* VLIW <1>: Processor pipeline description. - (line 223) -* 'vlshrM3' instruction pattern: Standard Names. (line 530) -* VMS: Filesystem. (line 37) -* VMS_DEBUGGING_INFO: VMS Debug. (line 8) -* VOIDmode: Machine Modes. (line 192) -* VOID_TYPE: Types. (line 6) -* volatil: Flags. (line 328) -* 'volatil', in 'insn', 'call_insn', 'jump_insn', 'code_label', 'jump_table_data', 'barrier', and 'note': Flags. - (line 44) -* 'volatil', in 'label_ref' and 'reg_label': Flags. (line 65) -* 'volatil', in 'mem', 'asm_operands', and 'asm_input': Flags. - (line 76) -* 'volatil', in 'reg': Flags. (line 98) -* 'volatil', in 'subreg': Flags. (line 170) -* 'volatil', in 'subreg' <1>: Flags. (line 180) -* 'volatil', in 'symbol_ref': Flags. (line 206) -* volatile memory references: Flags. (line 329) -* 'volatile', in 'prefetch': Flags. (line 214) -* voting between constraint alternatives: Class Preferences. (line 6) -* 'vrotlM3' instruction pattern: Standard Names. (line 530) -* 'vrotrM3' instruction pattern: Standard Names. (line 530) -* walk_dominator_tree: SSA. (line 227) -* walk_gimple_op: Statement and operand traversals. - (line 30) -* walk_gimple_seq: Statement and operand traversals. - (line 47) -* walk_gimple_stmt: Statement and operand traversals. - (line 10) -* WCHAR_TYPE: Type Layout. (line 208) -* WCHAR_TYPE_SIZE: Type Layout. (line 216) -* which_alternative: Output Statement. (line 58) -* WHILE_BODY: Statements for C++. (line 6) -* WHILE_COND: Statements for C++. (line 6) -* WHILE_STMT: Statements for C++. (line 6) -* whopr: LTO. (line 6) -* WIDEST_HARDWARE_FP_SIZE: Type Layout. (line 153) -* 'window_save' instruction pattern: Standard Names. 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