Mercurial > hg > CbC > CbC_gcc
annotate gcc/stack-ptr-mod.c @ 158:494b0b89df80 default tip
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| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Mon, 25 May 2020 18:13:55 +0900 |
| parents | 1830386684a0 |
| children |
| rev | line source |
|---|---|
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
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1 /* Discover if the stack pointer is modified in a function. |
| 145 | 2 Copyright (C) 2007-2020 Free Software Foundation, Inc. |
| 0 | 3 |
| 4 This file is part of GCC. | |
| 5 | |
| 6 GCC is free software; you can redistribute it and/or modify it under | |
| 7 the terms of the GNU General Public License as published by the Free | |
| 8 Software Foundation; either version 3, or (at your option) any later | |
| 9 version. | |
| 10 | |
| 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 for more details. | |
| 15 | |
| 16 You should have received a copy of the GNU General Public License | |
| 17 along with GCC; see the file COPYING3. If not see | |
| 18 <http://www.gnu.org/licenses/>. */ | |
| 19 | |
| 20 #include "config.h" | |
| 21 #include "system.h" | |
| 22 #include "coretypes.h" | |
| 111 | 23 #include "backend.h" |
| 0 | 24 #include "rtl.h" |
| 111 | 25 #include "df.h" |
| 26 #include "memmodel.h" | |
| 27 #include "emit-rtl.h" | |
| 0 | 28 #include "tree-pass.h" |
| 29 | |
| 30 /* Determine if the stack pointer is constant over the life of the function. | |
| 31 Only useful before prologues have been emitted. */ | |
| 32 | |
| 33 static void | |
| 34 notice_stack_pointer_modification_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, | |
| 35 void *data ATTRIBUTE_UNUSED) | |
| 36 { | |
| 37 if (x == stack_pointer_rtx | |
| 38 /* The stack pointer is only modified indirectly as the result | |
| 39 of a push until later. See the comments in rtl.texi | |
| 40 regarding Embedded Side-Effects on Addresses. */ | |
| 41 || (MEM_P (x) | |
| 42 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == RTX_AUTOINC | |
| 43 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx)) | |
| 111 | 44 crtl->sp_is_unchanging = 0; |
| 0 | 45 } |
| 46 | |
| 111 | 47 /* Some targets can emit simpler epilogues if they know that sp was |
| 48 not ever modified during the function. After reload, of course, | |
| 49 we've already emitted the epilogue so there's no sense searching. */ | |
| 50 | |
| 51 namespace { | |
| 52 | |
| 53 const pass_data pass_data_stack_ptr_mod = | |
| 54 { | |
| 55 RTL_PASS, /* type */ | |
| 56 "*stack_ptr_mod", /* name */ | |
| 57 OPTGROUP_NONE, /* optinfo_flags */ | |
| 58 TV_NONE, /* tv_id */ | |
| 59 0, /* properties_required */ | |
| 60 0, /* properties_provided */ | |
| 61 0, /* properties_destroyed */ | |
| 62 0, /* todo_flags_start */ | |
| 63 0, /* todo_flags_finish */ | |
| 64 }; | |
| 65 | |
| 66 class pass_stack_ptr_mod : public rtl_opt_pass | |
| 67 { | |
| 68 public: | |
| 69 pass_stack_ptr_mod (gcc::context *ctxt) | |
| 70 : rtl_opt_pass (pass_data_stack_ptr_mod, ctxt) | |
| 71 {} | |
| 72 | |
| 73 /* opt_pass methods: */ | |
| 74 virtual unsigned int execute (function *); | |
| 75 | |
| 76 }; // class pass_stack_ptr_mod | |
| 77 | |
| 78 unsigned int | |
| 79 pass_stack_ptr_mod::execute (function *fun) | |
| 0 | 80 { |
| 81 basic_block bb; | |
| 111 | 82 rtx_insn *insn; |
| 0 | 83 |
| 84 /* Assume that the stack pointer is unchanging if alloca hasn't | |
| 85 been used. */ | |
| 111 | 86 crtl->sp_is_unchanging = !fun->calls_alloca; |
| 87 if (crtl->sp_is_unchanging) | |
| 88 FOR_EACH_BB_FN (bb, fun) | |
| 0 | 89 FOR_BB_INSNS (bb, insn) |
| 90 { | |
| 91 if (INSN_P (insn)) | |
| 92 { | |
| 93 /* Check if insn modifies the stack pointer. */ | |
| 145 | 94 note_stores (insn, notice_stack_pointer_modification_1, NULL); |
| 111 | 95 if (! crtl->sp_is_unchanging) |
| 96 return 0; | |
| 0 | 97 } |
| 98 } | |
| 99 | |
| 100 /* The value coming into this pass was 0, and the exit block uses | |
| 101 are based on this. If the value is now 1, we need to redo the | |
| 102 exit block uses. */ | |
| 111 | 103 if (df && crtl->sp_is_unchanging) |
| 0 | 104 df_update_exit_block_uses (); |
| 105 | |
| 106 return 0; | |
| 107 } | |
| 108 | |
| 111 | 109 } // anon namespace |
| 110 | |
| 111 rtl_opt_pass * | |
| 112 make_pass_stack_ptr_mod (gcc::context *ctxt) | |
| 0 | 113 { |
| 111 | 114 return new pass_stack_ptr_mod (ctxt); |
| 115 } |