Mercurial > hg > CbC > CbC_gcc
annotate gcc/cfgbuild.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 |
|---|---|
| 0 | 1 /* Control flow graph building code for GNU compiler. |
| 145 | 2 Copyright (C) 1987-2020 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 | |
| 21 #include "config.h" | |
| 22 #include "system.h" | |
| 23 #include "coretypes.h" | |
| 111 | 24 #include "backend.h" |
| 0 | 25 #include "rtl.h" |
| 111 | 26 #include "cfghooks.h" |
| 27 #include "memmodel.h" | |
| 28 #include "emit-rtl.h" | |
| 29 #include "cfgrtl.h" | |
| 30 #include "cfganal.h" | |
| 31 #include "cfgbuild.h" | |
| 0 | 32 #include "except.h" |
| 111 | 33 #include "stmt.h" |
| 0 | 34 |
| 35 static void make_edges (basic_block, basic_block, int); | |
| 36 static void make_label_edge (sbitmap, basic_block, rtx, int); | |
| 37 static void find_bb_boundaries (basic_block); | |
| 38 static void compute_outgoing_frequencies (basic_block); | |
| 39 | |
| 40 /* Return true if insn is something that should be contained inside basic | |
| 41 block. */ | |
| 42 | |
| 43 bool | |
| 111 | 44 inside_basic_block_p (const rtx_insn *insn) |
| 0 | 45 { |
| 46 switch (GET_CODE (insn)) | |
| 47 { | |
| 48 case CODE_LABEL: | |
| 49 /* Avoid creating of basic block for jumptables. */ | |
| 50 return (NEXT_INSN (insn) == 0 | |
| 111 | 51 || ! JUMP_TABLE_DATA_P (NEXT_INSN (insn))); |
| 0 | 52 |
| 53 case JUMP_INSN: | |
| 54 case CALL_INSN: | |
| 55 case INSN: | |
|
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56 case DEBUG_INSN: |
| 0 | 57 return true; |
| 58 | |
| 111 | 59 case JUMP_TABLE_DATA: |
| 0 | 60 case BARRIER: |
| 61 case NOTE: | |
| 62 return false; | |
| 63 | |
| 64 default: | |
| 65 gcc_unreachable (); | |
| 66 } | |
| 67 } | |
| 68 | |
| 69 /* Return true if INSN may cause control flow transfer, so it should be last in | |
| 70 the basic block. */ | |
| 71 | |
| 72 bool | |
| 111 | 73 control_flow_insn_p (const rtx_insn *insn) |
| 0 | 74 { |
| 75 switch (GET_CODE (insn)) | |
| 76 { | |
| 77 case NOTE: | |
| 78 case CODE_LABEL: | |
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79 case DEBUG_INSN: |
| 0 | 80 return false; |
| 81 | |
| 82 case JUMP_INSN: | |
| 111 | 83 return true; |
| 0 | 84 |
| 85 case CALL_INSN: | |
| 86 /* Noreturn and sibling call instructions terminate the basic blocks | |
| 87 (but only if they happen unconditionally). */ | |
| 88 if ((SIBLING_CALL_P (insn) | |
| 89 || find_reg_note (insn, REG_NORETURN, 0)) | |
| 90 && GET_CODE (PATTERN (insn)) != COND_EXEC) | |
| 91 return true; | |
|
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92 |
| 0 | 93 /* Call insn may return to the nonlocal goto handler. */ |
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94 if (can_nonlocal_goto (insn)) |
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95 return true; |
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96 break; |
| 0 | 97 |
| 98 case INSN: | |
| 99 /* Treat trap instructions like noreturn calls (same provision). */ | |
| 100 if (GET_CODE (PATTERN (insn)) == TRAP_IF | |
| 101 && XEXP (PATTERN (insn), 0) == const1_rtx) | |
| 102 return true; | |
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103 if (!cfun->can_throw_non_call_exceptions) |
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104 return false; |
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105 break; |
| 0 | 106 |
| 111 | 107 case JUMP_TABLE_DATA: |
| 0 | 108 case BARRIER: |
| 111 | 109 /* It is nonsense to reach this when looking for the |
| 0 | 110 end of basic block, but before dead code is eliminated |
| 111 this may happen. */ | |
| 112 return false; | |
| 113 | |
| 114 default: | |
| 115 gcc_unreachable (); | |
| 116 } | |
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117 |
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118 return can_throw_internal (insn); |
| 0 | 119 } |
| 120 | |
| 121 | |
| 122 /* Create an edge between two basic blocks. FLAGS are auxiliary information | |
| 123 about the edge that is accumulated between calls. */ | |
| 124 | |
| 125 /* Create an edge from a basic block to a label. */ | |
| 126 | |
| 127 static void | |
| 128 make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags) | |
| 129 { | |
| 130 gcc_assert (LABEL_P (label)); | |
| 131 | |
| 132 /* If the label was never emitted, this insn is junk, but avoid a | |
| 133 crash trying to refer to BLOCK_FOR_INSN (label). This can happen | |
| 134 as a result of a syntax error and a diagnostic has already been | |
| 135 printed. */ | |
| 136 | |
| 137 if (INSN_UID (label) == 0) | |
| 138 return; | |
| 139 | |
| 140 cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags); | |
| 141 } | |
| 142 | |
| 143 /* Create the edges generated by INSN in REGION. */ | |
| 144 | |
| 145 void | |
| 146 rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn) | |
| 147 { | |
|
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148 eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn); |
| 0 | 149 |
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150 if (lp) |
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151 { |
| 111 | 152 rtx_insn *label = lp->landing_pad; |
| 0 | 153 |
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154 /* During initial rtl generation, use the post_landing_pad. */ |
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155 if (label == NULL) |
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156 { |
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157 gcc_assert (lp->post_landing_pad); |
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158 label = label_rtx (lp->post_landing_pad); |
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159 } |
| 0 | 160 |
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161 make_label_edge (edge_cache, src, label, |
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162 EDGE_ABNORMAL | EDGE_EH |
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163 | (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0)); |
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164 } |
| 0 | 165 } |
| 166 | |
| 167 /* States of basic block as seen by find_many_sub_basic_blocks. */ | |
| 168 enum state { | |
| 169 /* Basic blocks created via split_block belong to this state. | |
| 170 make_edges will examine these basic blocks to see if we need to | |
| 171 create edges going out of them. */ | |
| 172 BLOCK_NEW = 0, | |
| 173 | |
| 174 /* Basic blocks that do not need examining belong to this state. | |
| 175 These blocks will be left intact. In particular, make_edges will | |
| 176 not create edges going out of these basic blocks. */ | |
| 177 BLOCK_ORIGINAL, | |
| 178 | |
| 179 /* Basic blocks that may need splitting (due to a label appearing in | |
| 180 the middle, etc) belong to this state. After splitting them, | |
| 181 make_edges will create edges going out of them as needed. */ | |
| 182 BLOCK_TO_SPLIT | |
| 183 }; | |
| 184 | |
| 185 #define STATE(BB) (enum state) ((size_t) (BB)->aux) | |
| 186 #define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE)) | |
| 187 | |
| 188 /* Used internally by purge_dead_tablejump_edges, ORed into state. */ | |
| 189 #define BLOCK_USED_BY_TABLEJUMP 32 | |
| 190 #define FULL_STATE(BB) ((size_t) (BB)->aux) | |
| 191 | |
| 192 /* Identify the edges going out of basic blocks between MIN and MAX, | |
| 193 inclusive, that have their states set to BLOCK_NEW or | |
| 194 BLOCK_TO_SPLIT. | |
| 195 | |
| 196 UPDATE_P should be nonzero if we are updating CFG and zero if we | |
| 197 are building CFG from scratch. */ | |
| 198 | |
| 199 static void | |
| 200 make_edges (basic_block min, basic_block max, int update_p) | |
| 201 { | |
| 202 basic_block bb; | |
| 203 sbitmap edge_cache = NULL; | |
| 204 | |
| 205 /* Heavy use of computed goto in machine-generated code can lead to | |
| 206 nearly fully-connected CFGs. In that case we spend a significant | |
| 207 amount of time searching the edge lists for duplicates. */ | |
| 111 | 208 if (!vec_safe_is_empty (forced_labels) |
| 209 || cfun->cfg->max_jumptable_ents > 100) | |
| 210 edge_cache = sbitmap_alloc (last_basic_block_for_fn (cfun)); | |
| 0 | 211 |
| 212 /* By nature of the way these get numbered, ENTRY_BLOCK_PTR->next_bb block | |
| 213 is always the entry. */ | |
| 111 | 214 if (min == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb) |
| 215 make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), min, EDGE_FALLTHRU); | |
| 0 | 216 |
| 217 FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) | |
| 218 { | |
| 111 | 219 rtx_insn *insn; |
| 0 | 220 enum rtx_code code; |
| 221 edge e; | |
| 222 edge_iterator ei; | |
| 223 | |
| 224 if (STATE (bb) == BLOCK_ORIGINAL) | |
| 225 continue; | |
| 226 | |
| 227 /* If we have an edge cache, cache edges going out of BB. */ | |
| 228 if (edge_cache) | |
| 229 { | |
| 111 | 230 bitmap_clear (edge_cache); |
| 0 | 231 if (update_p) |
| 232 { | |
| 233 FOR_EACH_EDGE (e, ei, bb->succs) | |
| 111 | 234 if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| 235 bitmap_set_bit (edge_cache, e->dest->index); | |
| 0 | 236 } |
| 237 } | |
| 238 | |
| 239 if (LABEL_P (BB_HEAD (bb)) | |
| 240 && LABEL_ALT_ENTRY_P (BB_HEAD (bb))) | |
| 111 | 241 cached_make_edge (NULL, ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0); |
| 0 | 242 |
| 243 /* Examine the last instruction of the block, and discover the | |
| 244 ways we can leave the block. */ | |
| 245 | |
| 246 insn = BB_END (bb); | |
| 247 code = GET_CODE (insn); | |
| 248 | |
| 249 /* A branch. */ | |
| 250 if (code == JUMP_INSN) | |
| 251 { | |
| 252 rtx tmp; | |
| 111 | 253 rtx_jump_table_data *table; |
| 0 | 254 |
| 255 /* Recognize a non-local goto as a branch outside the | |
| 256 current function. */ | |
|
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257 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) |
| 0 | 258 ; |
| 259 | |
| 260 /* Recognize a tablejump and do the right thing. */ | |
| 111 | 261 else if (tablejump_p (insn, NULL, &table)) |
| 0 | 262 { |
| 111 | 263 rtvec vec = table->get_labels (); |
| 0 | 264 int j; |
| 265 | |
| 266 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
| 267 make_label_edge (edge_cache, bb, | |
| 268 XEXP (RTVEC_ELT (vec, j), 0), 0); | |
| 269 | |
| 270 /* Some targets (eg, ARM) emit a conditional jump that also | |
| 271 contains the out-of-range target. Scan for these and | |
| 272 add an edge if necessary. */ | |
| 273 if ((tmp = single_set (insn)) != NULL | |
| 274 && SET_DEST (tmp) == pc_rtx | |
| 275 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
| 276 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) | |
| 277 make_label_edge (edge_cache, bb, | |
| 111 | 278 label_ref_label (XEXP (SET_SRC (tmp), 2)), 0); |
| 0 | 279 } |
| 280 | |
| 281 /* If this is a computed jump, then mark it as reaching | |
| 282 everything on the forced_labels list. */ | |
| 283 else if (computed_jump_p (insn)) | |
| 284 { | |
| 111 | 285 rtx_insn *insn; |
| 286 unsigned int i; | |
| 287 FOR_EACH_VEC_SAFE_ELT (forced_labels, i, insn) | |
| 288 make_label_edge (edge_cache, bb, insn, EDGE_ABNORMAL); | |
| 0 | 289 } |
| 290 | |
| 291 /* Returns create an exit out. */ | |
| 292 else if (returnjump_p (insn)) | |
| 111 | 293 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0); |
| 0 | 294 |
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295 /* Recognize asm goto and do the right thing. */ |
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296 else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL) |
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297 { |
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298 int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp); |
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299 for (i = 0; i < n; ++i) |
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300 make_label_edge (edge_cache, bb, |
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301 XEXP (ASM_OPERANDS_LABEL (tmp, i), 0), 0); |
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302 } |
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303 |
| 0 | 304 /* Otherwise, we have a plain conditional or unconditional jump. */ |
| 305 else | |
| 306 { | |
| 307 gcc_assert (JUMP_LABEL (insn)); | |
| 308 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0); | |
| 309 } | |
| 310 } | |
| 311 | |
| 312 /* If this is a sibling call insn, then this is in effect a combined call | |
| 313 and return, and so we need an edge to the exit block. No need to | |
| 314 worry about EH edges, since we wouldn't have created the sibling call | |
| 315 in the first place. */ | |
| 316 if (code == CALL_INSN && SIBLING_CALL_P (insn)) | |
| 111 | 317 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), |
| 0 | 318 EDGE_SIBCALL | EDGE_ABNORMAL); |
| 319 | |
| 320 /* If this is a CALL_INSN, then mark it as reaching the active EH | |
| 321 handler for this CALL_INSN. If we're handling non-call | |
| 322 exceptions then any insn can reach any of the active handlers. | |
| 323 Also mark the CALL_INSN as reaching any nonlocal goto handler. */ | |
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324 else if (code == CALL_INSN || cfun->can_throw_non_call_exceptions) |
| 0 | 325 { |
| 326 /* Add any appropriate EH edges. */ | |
| 327 rtl_make_eh_edge (edge_cache, bb, insn); | |
| 328 | |
| 111 | 329 if (code == CALL_INSN) |
| 0 | 330 { |
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331 if (can_nonlocal_goto (insn)) |
| 111 | 332 { |
| 333 /* ??? This could be made smarter: in some cases it's | |
| 334 possible to tell that certain calls will not do a | |
| 335 nonlocal goto. For example, if the nested functions | |
| 336 that do the nonlocal gotos do not have their addresses | |
| 337 taken, then only calls to those functions or to other | |
| 338 nested functions that use them could possibly do | |
| 339 nonlocal gotos. */ | |
| 340 for (rtx_insn_list *x = nonlocal_goto_handler_labels; | |
| 341 x; | |
| 342 x = x->next ()) | |
| 343 make_label_edge (edge_cache, bb, x->insn (), | |
| 344 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); | |
| 345 } | |
| 346 | |
| 347 if (flag_tm) | |
| 348 { | |
| 349 rtx note; | |
| 350 for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
| 351 if (REG_NOTE_KIND (note) == REG_TM) | |
| 352 make_label_edge (edge_cache, bb, XEXP (note, 0), | |
| 353 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); | |
| 354 } | |
| 0 | 355 } |
| 356 } | |
| 357 | |
| 358 /* Find out if we can drop through to the next block. */ | |
| 359 insn = NEXT_INSN (insn); | |
| 111 | 360 e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun)); |
| 0 | 361 if (e && e->flags & EDGE_FALLTHRU) |
| 362 insn = NULL; | |
| 363 | |
| 364 while (insn | |
| 365 && NOTE_P (insn) | |
| 366 && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK) | |
| 367 insn = NEXT_INSN (insn); | |
| 368 | |
| 369 if (!insn) | |
| 111 | 370 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), |
| 371 EDGE_FALLTHRU); | |
| 372 else if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
| 0 | 373 { |
| 374 if (insn == BB_HEAD (bb->next_bb)) | |
| 375 cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU); | |
| 376 } | |
| 377 } | |
| 378 | |
| 379 if (edge_cache) | |
| 111 | 380 sbitmap_free (edge_cache); |
| 0 | 381 } |
| 382 | |
| 383 static void | |
| 384 mark_tablejump_edge (rtx label) | |
| 385 { | |
| 386 basic_block bb; | |
| 387 | |
| 388 gcc_assert (LABEL_P (label)); | |
| 389 /* See comment in make_label_edge. */ | |
| 390 if (INSN_UID (label) == 0) | |
| 391 return; | |
| 392 bb = BLOCK_FOR_INSN (label); | |
| 393 SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP); | |
| 394 } | |
| 395 | |
| 396 static void | |
| 111 | 397 purge_dead_tablejump_edges (basic_block bb, rtx_jump_table_data *table) |
| 0 | 398 { |
| 111 | 399 rtx_insn *insn = BB_END (bb); |
| 400 rtx tmp; | |
| 0 | 401 rtvec vec; |
| 402 int j; | |
| 403 edge_iterator ei; | |
| 404 edge e; | |
| 405 | |
| 111 | 406 vec = table->get_labels (); |
| 0 | 407 |
| 408 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
| 409 mark_tablejump_edge (XEXP (RTVEC_ELT (vec, j), 0)); | |
| 410 | |
| 411 /* Some targets (eg, ARM) emit a conditional jump that also | |
| 412 contains the out-of-range target. Scan for these and | |
| 413 add an edge if necessary. */ | |
| 414 if ((tmp = single_set (insn)) != NULL | |
| 415 && SET_DEST (tmp) == pc_rtx | |
| 416 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
| 417 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) | |
| 111 | 418 mark_tablejump_edge (label_ref_label (XEXP (SET_SRC (tmp), 2))); |
| 0 | 419 |
| 420 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) | |
| 421 { | |
| 422 if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP) | |
| 423 SET_STATE (e->dest, FULL_STATE (e->dest) | |
| 424 & ~(size_t) BLOCK_USED_BY_TABLEJUMP); | |
| 425 else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH))) | |
| 426 { | |
| 427 remove_edge (e); | |
| 428 continue; | |
| 429 } | |
| 430 ei_next (&ei); | |
| 431 } | |
| 432 } | |
| 433 | |
| 434 /* Scan basic block BB for possible BB boundaries inside the block | |
| 435 and create new basic blocks in the progress. */ | |
| 436 | |
| 437 static void | |
| 438 find_bb_boundaries (basic_block bb) | |
| 439 { | |
| 440 basic_block orig_bb = bb; | |
| 111 | 441 rtx_insn *insn = BB_HEAD (bb); |
| 442 rtx_insn *end = BB_END (bb), *x; | |
| 443 rtx_jump_table_data *table; | |
| 444 rtx_insn *flow_transfer_insn = NULL; | |
| 445 rtx_insn *debug_insn = NULL; | |
| 0 | 446 edge fallthru = NULL; |
| 131 | 447 bool skip_purge; |
| 0 | 448 |
| 111 | 449 if (insn == end) |
| 0 | 450 return; |
| 451 | |
| 131 | 452 if (DEBUG_INSN_P (insn) || DEBUG_INSN_P (end)) |
| 453 { | |
| 454 /* Check whether, without debug insns, the insn==end test above | |
| 455 would have caused us to return immediately, and behave the | |
| 456 same way even with debug insns. If we don't do this, debug | |
| 457 insns could cause us to purge dead edges at different times, | |
| 458 which could in turn change the cfg and affect codegen | |
| 459 decisions in subtle but undesirable ways. */ | |
| 460 while (insn != end && DEBUG_INSN_P (insn)) | |
| 461 insn = NEXT_INSN (insn); | |
| 462 rtx_insn *e = end; | |
| 463 while (insn != e && DEBUG_INSN_P (e)) | |
| 464 e = PREV_INSN (e); | |
| 465 if (insn == e) | |
| 466 { | |
| 467 /* If there are debug insns after a single insn that is a | |
| 468 control flow insn in the block, we'd have left right | |
| 469 away, but we should clean up the debug insns after the | |
| 470 control flow insn, because they can't remain in the same | |
| 471 block. So, do the debug insn cleaning up, but then bail | |
| 472 out without purging dead edges as we would if the debug | |
| 473 insns hadn't been there. */ | |
| 474 if (e != end && !DEBUG_INSN_P (e) && control_flow_insn_p (e)) | |
| 475 { | |
| 476 skip_purge = true; | |
| 477 flow_transfer_insn = e; | |
| 478 goto clean_up_debug_after_control_flow; | |
| 479 } | |
| 480 return; | |
| 481 } | |
| 482 } | |
| 483 | |
| 0 | 484 if (LABEL_P (insn)) |
| 485 insn = NEXT_INSN (insn); | |
| 486 | |
| 487 /* Scan insn chain and try to find new basic block boundaries. */ | |
| 488 while (1) | |
| 489 { | |
| 490 enum rtx_code code = GET_CODE (insn); | |
| 491 | |
| 111 | 492 if (code == DEBUG_INSN) |
| 493 { | |
| 494 if (flow_transfer_insn && !debug_insn) | |
| 495 debug_insn = insn; | |
| 496 } | |
|
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497 /* In case we've previously seen an insn that effects a control |
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498 flow transfer, split the block. */ |
| 111 | 499 else if ((flow_transfer_insn || code == CODE_LABEL) |
| 500 && inside_basic_block_p (insn)) | |
| 0 | 501 { |
| 111 | 502 rtx_insn *prev = PREV_INSN (insn); |
| 503 | |
| 504 /* If the first non-debug inside_basic_block_p insn after a control | |
| 505 flow transfer is not a label, split the block before the debug | |
| 506 insn instead of before the non-debug insn, so that the debug | |
| 507 insns are not lost. */ | |
| 508 if (debug_insn && code != CODE_LABEL && code != BARRIER) | |
| 509 prev = PREV_INSN (debug_insn); | |
| 510 fallthru = split_block (bb, prev); | |
| 0 | 511 if (flow_transfer_insn) |
| 512 { | |
| 513 BB_END (bb) = flow_transfer_insn; | |
| 514 | |
| 111 | 515 rtx_insn *next; |
| 0 | 516 /* Clean up the bb field for the insns between the blocks. */ |
| 517 for (x = NEXT_INSN (flow_transfer_insn); | |
| 518 x != BB_HEAD (fallthru->dest); | |
| 111 | 519 x = next) |
| 520 { | |
| 521 next = NEXT_INSN (x); | |
| 522 /* Debug insns should not be in between basic blocks, | |
| 523 drop them on the floor. */ | |
| 524 if (DEBUG_INSN_P (x)) | |
| 525 delete_insn (x); | |
| 526 else if (!BARRIER_P (x)) | |
| 527 set_block_for_insn (x, NULL); | |
| 528 } | |
| 0 | 529 } |
| 530 | |
| 531 bb = fallthru->dest; | |
| 532 remove_edge (fallthru); | |
| 111 | 533 /* BB is unreachable at this point - we need to determine its profile |
| 534 once edges are built. */ | |
| 535 bb->count = profile_count::uninitialized (); | |
| 536 flow_transfer_insn = NULL; | |
| 537 debug_insn = NULL; | |
|
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538 if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn)) |
| 111 | 539 make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0); |
| 0 | 540 } |
|
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541 else if (code == BARRIER) |
| 0 | 542 { |
|
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543 /* __builtin_unreachable () may cause a barrier to be emitted in |
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544 the middle of a BB. We need to split it in the same manner as |
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545 if the barrier were preceded by a control_flow_insn_p insn. */ |
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546 if (!flow_transfer_insn) |
| 131 | 547 flow_transfer_insn = prev_nonnote_nondebug_insn_bb (insn); |
| 0 | 548 } |
| 549 | |
| 550 if (control_flow_insn_p (insn)) | |
| 551 flow_transfer_insn = insn; | |
| 552 if (insn == end) | |
| 553 break; | |
| 554 insn = NEXT_INSN (insn); | |
| 555 } | |
| 556 | |
| 557 /* In case expander replaced normal insn by sequence terminating by | |
| 558 return and barrier, or possibly other sequence not behaving like | |
| 559 ordinary jump, we need to take care and move basic block boundary. */ | |
| 111 | 560 if (flow_transfer_insn && flow_transfer_insn != end) |
| 0 | 561 { |
| 131 | 562 skip_purge = false; |
| 563 | |
| 564 clean_up_debug_after_control_flow: | |
| 0 | 565 BB_END (bb) = flow_transfer_insn; |
| 566 | |
| 567 /* Clean up the bb field for the insns that do not belong to BB. */ | |
| 111 | 568 rtx_insn *next; |
| 569 for (x = NEXT_INSN (flow_transfer_insn); ; x = next) | |
| 0 | 570 { |
| 111 | 571 next = NEXT_INSN (x); |
| 572 /* Debug insns should not be in between basic blocks, | |
| 573 drop them on the floor. */ | |
| 574 if (DEBUG_INSN_P (x)) | |
| 575 delete_insn (x); | |
| 576 else if (!BARRIER_P (x)) | |
| 0 | 577 set_block_for_insn (x, NULL); |
| 111 | 578 if (x == end) |
| 579 break; | |
| 0 | 580 } |
| 131 | 581 |
| 582 if (skip_purge) | |
| 583 return; | |
| 0 | 584 } |
| 585 | |
| 586 /* We've possibly replaced the conditional jump by conditional jump | |
| 587 followed by cleanup at fallthru edge, so the outgoing edges may | |
| 588 be dead. */ | |
| 589 purge_dead_edges (bb); | |
| 590 | |
| 591 /* purge_dead_edges doesn't handle tablejump's, but if we have split the | |
| 592 basic block, we might need to kill some edges. */ | |
| 593 if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table)) | |
| 594 purge_dead_tablejump_edges (bb, table); | |
| 595 } | |
| 596 | |
| 597 /* Assume that frequency of basic block B is known. Compute frequencies | |
| 598 and probabilities of outgoing edges. */ | |
| 599 | |
| 600 static void | |
| 601 compute_outgoing_frequencies (basic_block b) | |
| 602 { | |
| 603 edge e, f; | |
| 604 edge_iterator ei; | |
| 605 | |
| 606 if (EDGE_COUNT (b->succs) == 2) | |
| 607 { | |
| 608 rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL); | |
| 609 int probability; | |
| 610 | |
| 611 if (note) | |
| 612 { | |
| 111 | 613 probability = XINT (note, 0); |
| 0 | 614 e = BRANCH_EDGE (b); |
| 111 | 615 e->probability |
| 616 = profile_probability::from_reg_br_prob_note (probability); | |
| 0 | 617 f = FALLTHRU_EDGE (b); |
| 111 | 618 f->probability = e->probability.invert (); |
| 0 | 619 return; |
| 620 } | |
| 111 | 621 else |
| 622 { | |
| 623 guess_outgoing_edge_probabilities (b); | |
| 624 } | |
| 0 | 625 } |
| 111 | 626 else if (single_succ_p (b)) |
| 0 | 627 { |
| 628 e = single_succ_edge (b); | |
| 111 | 629 e->probability = profile_probability::always (); |
| 0 | 630 return; |
| 631 } | |
| 111 | 632 else |
| 633 { | |
| 634 /* We rely on BBs with more than two successors to have sane probabilities | |
| 635 and do not guess them here. For BBs terminated by switch statements | |
| 636 expanded to jump-table jump, we have done the right thing during | |
| 637 expansion. For EH edges, we still guess the probabilities here. */ | |
| 638 bool complex_edge = false; | |
| 639 FOR_EACH_EDGE (e, ei, b->succs) | |
| 640 if (e->flags & EDGE_COMPLEX) | |
| 641 { | |
| 642 complex_edge = true; | |
| 643 break; | |
| 644 } | |
| 645 if (complex_edge) | |
| 646 guess_outgoing_edge_probabilities (b); | |
| 647 } | |
| 0 | 648 } |
| 649 | |
| 650 /* Assume that some pass has inserted labels or control flow | |
| 651 instructions within a basic block. Split basic blocks as needed | |
| 652 and create edges. */ | |
| 653 | |
| 654 void | |
| 655 find_many_sub_basic_blocks (sbitmap blocks) | |
| 656 { | |
| 657 basic_block bb, min, max; | |
| 111 | 658 bool found = false; |
| 659 auto_vec<unsigned int> n_succs; | |
| 660 n_succs.safe_grow_cleared (last_basic_block_for_fn (cfun)); | |
| 0 | 661 |
| 111 | 662 FOR_EACH_BB_FN (bb, cfun) |
| 0 | 663 SET_STATE (bb, |
| 111 | 664 bitmap_bit_p (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL); |
| 665 | |
| 666 FOR_EACH_BB_FN (bb, cfun) | |
| 667 if (STATE (bb) == BLOCK_TO_SPLIT) | |
| 668 { | |
| 669 int n = last_basic_block_for_fn (cfun); | |
| 670 unsigned int ns = EDGE_COUNT (bb->succs); | |
| 0 | 671 |
| 111 | 672 find_bb_boundaries (bb); |
| 673 if (n == last_basic_block_for_fn (cfun) && ns == EDGE_COUNT (bb->succs)) | |
| 674 n_succs[bb->index] = EDGE_COUNT (bb->succs); | |
| 675 } | |
| 0 | 676 |
| 111 | 677 FOR_EACH_BB_FN (bb, cfun) |
| 0 | 678 if (STATE (bb) != BLOCK_ORIGINAL) |
| 111 | 679 { |
| 680 found = true; | |
| 681 break; | |
| 682 } | |
| 683 | |
| 684 if (!found) | |
| 685 return; | |
| 0 | 686 |
| 687 min = max = bb; | |
| 111 | 688 for (; bb != EXIT_BLOCK_PTR_FOR_FN (cfun); bb = bb->next_bb) |
| 0 | 689 if (STATE (bb) != BLOCK_ORIGINAL) |
| 690 max = bb; | |
| 691 | |
| 692 /* Now re-scan and wire in all edges. This expect simple (conditional) | |
| 693 jumps at the end of each new basic blocks. */ | |
| 694 make_edges (min, max, 1); | |
| 695 | |
| 696 /* Update branch probabilities. Expect only (un)conditional jumps | |
| 697 to be created with only the forward edges. */ | |
| 111 | 698 if (profile_status_for_fn (cfun) != PROFILE_ABSENT) |
| 0 | 699 FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) |
| 700 { | |
| 701 edge e; | |
| 702 edge_iterator ei; | |
| 703 | |
| 704 if (STATE (bb) == BLOCK_ORIGINAL) | |
| 705 continue; | |
| 706 if (STATE (bb) == BLOCK_NEW) | |
| 707 { | |
| 111 | 708 bool initialized_src = false, uninitialized_src = false; |
| 709 bb->count = profile_count::zero (); | |
| 0 | 710 FOR_EACH_EDGE (e, ei, bb->preds) |
| 711 { | |
| 111 | 712 if (e->count ().initialized_p ()) |
| 713 { | |
| 714 bb->count += e->count (); | |
| 715 initialized_src = true; | |
| 716 } | |
| 717 else | |
| 718 uninitialized_src = true; | |
| 0 | 719 } |
| 111 | 720 /* When some edges are missing with read profile, this is |
| 721 most likely because RTL expansion introduced loop. | |
| 722 When profile is guessed we may have BB that is reachable | |
| 723 from unlikely path as well as from normal path. | |
| 724 | |
| 725 TODO: We should handle loops created during BB expansion | |
| 726 correctly here. For now we assume all those loop to cycle | |
| 727 precisely once. */ | |
| 728 if (!initialized_src | |
| 729 || (uninitialized_src | |
| 131 | 730 && profile_status_for_fn (cfun) < PROFILE_GUESSED)) |
| 111 | 731 bb->count = profile_count::uninitialized (); |
| 732 } | |
| 733 /* If nothing changed, there is no need to create new BBs. */ | |
| 734 else if (EDGE_COUNT (bb->succs) == n_succs[bb->index]) | |
| 735 { | |
| 736 /* In rare occassions RTL expansion might have mistakely assigned | |
| 737 a probabilities different from what is in CFG. This happens | |
| 738 when we try to split branch to two but optimize out the | |
| 739 second branch during the way. See PR81030. */ | |
| 740 if (JUMP_P (BB_END (bb)) && any_condjump_p (BB_END (bb)) | |
| 741 && EDGE_COUNT (bb->succs) >= 2) | |
| 742 update_br_prob_note (bb); | |
| 743 continue; | |
| 0 | 744 } |
| 745 | |
| 746 compute_outgoing_frequencies (bb); | |
| 747 } | |
| 748 | |
| 111 | 749 FOR_EACH_BB_FN (bb, cfun) |
| 0 | 750 SET_STATE (bb, 0); |
| 751 } |