Mercurial > hg > CbC > CbC_gcc
annotate gcc/init-regs.c @ 131:84e7813d76e9
gcc-8.2
| author | mir3636 |
|---|---|
| date | Thu, 25 Oct 2018 07:37:49 +0900 |
| parents | 04ced10e8804 |
| children | 1830386684a0 |
| 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 /* Initialization of uninitialized regs. |
| 131 | 2 Copyright (C) 2007-2018 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" |
| 24 #include "rtl.h" | |
| 0 | 25 #include "tree.h" |
| 111 | 26 #include "df.h" |
| 27 #include "memmodel.h" | |
| 28 #include "emit-rtl.h" | |
| 0 | 29 #include "expr.h" |
| 30 #include "tree-pass.h" | |
| 31 | |
| 32 /* Check all of the uses of pseudo variables. If any use that is MUST | |
| 33 uninitialized, add a store of 0 immediately before it. For | |
| 34 subregs, this makes combine happy. For full word regs, this makes | |
| 35 other optimizations, like the register allocator and the reg-stack | |
| 36 happy as well as papers over some problems on the arm and other | |
| 37 processors where certain isa constraints cannot be handled by gcc. | |
| 38 These are of the form where two operands to an insn my not be the | |
| 39 same. The ra will only make them the same if they do not | |
| 40 interfere, and this can only happen if one is not initialized. | |
| 41 | |
| 42 There is also the unfortunate consequence that this may mask some | |
| 43 buggy programs where people forget to initialize stack variable. | |
| 44 Any programmer with half a brain would look at the uninitialized | |
| 45 variable warnings. */ | |
| 46 | |
| 47 static void | |
| 48 initialize_uninitialized_regs (void) | |
| 49 { | |
| 50 basic_block bb; | |
| 111 | 51 auto_bitmap already_genned; |
| 0 | 52 |
| 53 if (optimize == 1) | |
| 54 { | |
| 55 df_live_add_problem (); | |
| 56 df_live_set_all_dirty (); | |
| 57 } | |
| 58 | |
| 59 df_analyze (); | |
| 60 | |
| 111 | 61 FOR_EACH_BB_FN (bb, cfun) |
| 0 | 62 { |
| 111 | 63 rtx_insn *insn; |
| 0 | 64 bitmap lr = DF_LR_IN (bb); |
| 65 bitmap ur = DF_LIVE_IN (bb); | |
| 66 bitmap_clear (already_genned); | |
| 67 | |
| 68 FOR_BB_INSNS (bb, insn) | |
| 69 { | |
| 111 | 70 df_ref use; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
71 if (!NONDEBUG_INSN_P (insn)) |
| 0 | 72 continue; |
| 73 | |
| 111 | 74 FOR_EACH_INSN_USE (use, insn) |
| 0 | 75 { |
| 76 unsigned int regno = DF_REF_REGNO (use); | |
| 77 | |
| 78 /* Only do this for the pseudos. */ | |
| 79 if (regno < FIRST_PSEUDO_REGISTER) | |
| 80 continue; | |
| 81 | |
| 111 | 82 /* Ignore pseudo PIC register. */ |
| 83 if (pic_offset_table_rtx | |
| 84 && regno == REGNO (pic_offset_table_rtx)) | |
| 85 continue; | |
| 86 | |
| 0 | 87 /* Do not generate multiple moves for the same regno. |
| 88 This is common for sequences of subreg operations. | |
| 89 They would be deleted during combine but there is no | |
| 90 reason to churn the system. */ | |
| 91 if (bitmap_bit_p (already_genned, regno)) | |
| 92 continue; | |
| 93 | |
| 94 /* A use is MUST uninitialized if it reaches the top of | |
| 95 the block from the inside of the block (the lr test) | |
| 96 and no def for it reaches the top of the block from | |
| 97 outside of the block (the ur test). */ | |
| 98 if (bitmap_bit_p (lr, regno) | |
| 99 && (!bitmap_bit_p (ur, regno))) | |
| 100 { | |
| 111 | 101 rtx_insn *move_insn; |
| 0 | 102 rtx reg = DF_REF_REAL_REG (use); |
| 103 | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
104 bitmap_set_bit (already_genned, regno); |
| 0 | 105 |
| 106 start_sequence (); | |
| 111 | 107 emit_clobber (reg); |
| 0 | 108 emit_move_insn (reg, CONST0_RTX (GET_MODE (reg))); |
| 109 move_insn = get_insns (); | |
| 110 end_sequence (); | |
| 111 emit_insn_before (move_insn, insn); | |
| 112 if (dump_file) | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
113 fprintf (dump_file, |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
114 "adding initialization in %s of reg %d at in block %d for insn %d.\n", |
| 111 | 115 current_function_name (), regno, bb->index, |
| 116 INSN_UID (insn)); | |
| 0 | 117 } |
| 118 } | |
| 119 } | |
| 120 } | |
| 121 | |
| 122 if (optimize == 1) | |
| 123 { | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
124 if (dump_file) |
| 0 | 125 df_dump (dump_file); |
| 126 df_remove_problem (df_live); | |
| 127 } | |
| 128 } | |
| 129 | |
| 111 | 130 namespace { |
| 131 | |
| 132 const pass_data pass_data_initialize_regs = | |
| 133 { | |
| 134 RTL_PASS, /* type */ | |
| 135 "init-regs", /* name */ | |
| 136 OPTGROUP_NONE, /* optinfo_flags */ | |
| 137 TV_NONE, /* tv_id */ | |
| 138 0, /* properties_required */ | |
| 139 0, /* properties_provided */ | |
| 140 0, /* properties_destroyed */ | |
| 141 0, /* todo_flags_start */ | |
| 142 TODO_df_finish, /* todo_flags_finish */ | |
| 143 }; | |
| 144 | |
| 145 class pass_initialize_regs : public rtl_opt_pass | |
| 0 | 146 { |
| 111 | 147 public: |
| 148 pass_initialize_regs (gcc::context *ctxt) | |
| 149 : rtl_opt_pass (pass_data_initialize_regs, ctxt) | |
| 150 {} | |
| 151 | |
| 152 /* opt_pass methods: */ | |
| 153 virtual bool gate (function *) { return optimize > 0; } | |
| 154 virtual unsigned int execute (function *) | |
| 155 { | |
| 156 initialize_uninitialized_regs (); | |
| 157 return 0; | |
| 158 } | |
| 159 | |
| 160 }; // class pass_initialize_regs | |
| 161 | |
| 162 } // anon namespace | |
| 163 | |
| 164 rtl_opt_pass * | |
| 165 make_pass_initialize_regs (gcc::context *ctxt) | |
| 166 { | |
| 167 return new pass_initialize_regs (ctxt); | |
| 168 } |