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author | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
commit | 1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch) | |
tree | c607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/gcc/stack-ptr-mod.c | |
parent | 283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff) | |
download | toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.gz toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.bz2 toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.zip |
Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/gcc/stack-ptr-mod.c')
-rw-r--r-- | gcc-4.9/gcc/stack-ptr-mod.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/stack-ptr-mod.c b/gcc-4.9/gcc/stack-ptr-mod.c new file mode 100644 index 000000000..6b78085f1 --- /dev/null +++ b/gcc-4.9/gcc/stack-ptr-mod.c @@ -0,0 +1,128 @@ +/* Discover if the stack pointer is modified in a function. + Copyright (C) 2007-2014 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC 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, or (at your option) any later +version. + +GCC 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 GCC; see the file COPYING3. If not see +<http://www.gnu.org/licenses/>. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "tree.h" +#include "rtl.h" +#include "regs.h" +#include "expr.h" +#include "tree-pass.h" +#include "basic-block.h" +#include "flags.h" +#include "output.h" +#include "df.h" + +/* Determine if the stack pointer is constant over the life of the function. + Only useful before prologues have been emitted. */ + +static void +notice_stack_pointer_modification_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, + void *data ATTRIBUTE_UNUSED) +{ + if (x == stack_pointer_rtx + /* The stack pointer is only modified indirectly as the result + of a push until later. See the comments in rtl.texi + regarding Embedded Side-Effects on Addresses. */ + || (MEM_P (x) + && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == RTX_AUTOINC + && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx)) + crtl->sp_is_unchanging = 0; +} + +static void +notice_stack_pointer_modification (void) +{ + basic_block bb; + rtx insn; + + /* Assume that the stack pointer is unchanging if alloca hasn't + been used. */ + crtl->sp_is_unchanging = !cfun->calls_alloca; + if (crtl->sp_is_unchanging) + FOR_EACH_BB_FN (bb, cfun) + FOR_BB_INSNS (bb, insn) + { + if (INSN_P (insn)) + { + /* Check if insn modifies the stack pointer. */ + note_stores (PATTERN (insn), + notice_stack_pointer_modification_1, + NULL); + if (! crtl->sp_is_unchanging) + return; + } + } + + /* The value coming into this pass was 0, and the exit block uses + are based on this. If the value is now 1, we need to redo the + exit block uses. */ + if (df && crtl->sp_is_unchanging) + df_update_exit_block_uses (); +} + + /* Some targets can emit simpler epilogues if they know that sp was + not ever modified during the function. After reload, of course, + we've already emitted the epilogue so there's no sense searching. */ + +static unsigned int +rest_of_handle_stack_ptr_mod (void) +{ + notice_stack_pointer_modification (); + return 0; +} + +namespace { + +const pass_data pass_data_stack_ptr_mod = +{ + RTL_PASS, /* type */ + "*stack_ptr_mod", /* name */ + OPTGROUP_NONE, /* optinfo_flags */ + false, /* has_gate */ + true, /* has_execute */ + TV_NONE, /* tv_id */ + 0, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ +}; + +class pass_stack_ptr_mod : public rtl_opt_pass +{ +public: + pass_stack_ptr_mod (gcc::context *ctxt) + : rtl_opt_pass (pass_data_stack_ptr_mod, ctxt) + {} + + /* opt_pass methods: */ + unsigned int execute () { return rest_of_handle_stack_ptr_mod (); } + +}; // class pass_stack_ptr_mod + +} // anon namespace + +rtl_opt_pass * +make_pass_stack_ptr_mod (gcc::context *ctxt) +{ + return new pass_stack_ptr_mod (ctxt); +} |