Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 1 | /* Control flow graph manipulation code for GNU compiler. |
| 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
| 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, |
| 4 | 2011, 2012 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GCC. |
| 7 | |
| 8 | GCC is free software; you can redistribute it and/or modify it under |
| 9 | the terms of the GNU General Public License as published by the Free |
| 10 | Software Foundation; either version 3, or (at your option) any later |
| 11 | version. |
| 12 | |
| 13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| 14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 16 | for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with GCC; see the file COPYING3. If not see |
| 20 | <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | /* This file contains low level functions to manipulate the CFG and analyze it |
| 23 | that are aware of the RTL intermediate language. |
| 24 | |
| 25 | Available functionality: |
| 26 | - Basic CFG/RTL manipulation API documented in cfghooks.h |
| 27 | - CFG-aware instruction chain manipulation |
| 28 | delete_insn, delete_insn_chain |
| 29 | - Edge splitting and committing to edges |
| 30 | insert_insn_on_edge, commit_edge_insertions |
| 31 | - CFG updating after insn simplification |
| 32 | purge_dead_edges, purge_all_dead_edges |
| 33 | - CFG fixing after coarse manipulation |
| 34 | fixup_abnormal_edges |
| 35 | |
| 36 | Functions not supposed for generic use: |
| 37 | - Infrastructure to determine quickly basic block for insn |
| 38 | compute_bb_for_insn, update_bb_for_insn, set_block_for_insn, |
| 39 | - Edge redirection with updating and optimizing of insn chain |
| 40 | block_label, tidy_fallthru_edge, force_nonfallthru */ |
| 41 | |
| 42 | #include "config.h" |
| 43 | #include "system.h" |
| 44 | #include "coretypes.h" |
| 45 | #include "tm.h" |
| 46 | #include "tree.h" |
| 47 | #include "hard-reg-set.h" |
| 48 | #include "basic-block.h" |
| 49 | #include "regs.h" |
| 50 | #include "flags.h" |
| 51 | #include "function.h" |
| 52 | #include "except.h" |
| 53 | #include "rtl-error.h" |
| 54 | #include "tm_p.h" |
| 55 | #include "obstack.h" |
| 56 | #include "insn-attr.h" |
| 57 | #include "insn-config.h" |
| 58 | #include "expr.h" |
| 59 | #include "target.h" |
| 60 | #include "common/common-target.h" |
| 61 | #include "cfgloop.h" |
| 62 | #include "ggc.h" |
| 63 | #include "tree-pass.h" |
| 64 | #include "df.h" |
| 65 | |
| 66 | /* Holds the interesting leading and trailing notes for the function. |
| 67 | Only applicable if the CFG is in cfglayout mode. */ |
| 68 | static GTY(()) rtx cfg_layout_function_footer; |
| 69 | static GTY(()) rtx cfg_layout_function_header; |
| 70 | |
| 71 | static rtx skip_insns_after_block (basic_block); |
| 72 | static void record_effective_endpoints (void); |
| 73 | static rtx label_for_bb (basic_block); |
| 74 | static void fixup_reorder_chain (void); |
| 75 | |
| 76 | void verify_insn_chain (void); |
| 77 | static void fixup_fallthru_exit_predecessor (void); |
| 78 | static int can_delete_note_p (const_rtx); |
| 79 | static int can_delete_label_p (const_rtx); |
| 80 | static basic_block rtl_split_edge (edge); |
| 81 | static bool rtl_move_block_after (basic_block, basic_block); |
| 82 | static int rtl_verify_flow_info (void); |
| 83 | static basic_block cfg_layout_split_block (basic_block, void *); |
| 84 | static edge cfg_layout_redirect_edge_and_branch (edge, basic_block); |
| 85 | static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block); |
| 86 | static void cfg_layout_delete_block (basic_block); |
| 87 | static void rtl_delete_block (basic_block); |
| 88 | static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block); |
| 89 | static edge rtl_redirect_edge_and_branch (edge, basic_block); |
| 90 | static basic_block rtl_split_block (basic_block, void *); |
| 91 | static void rtl_dump_bb (FILE *, basic_block, int, int); |
| 92 | static int rtl_verify_flow_info_1 (void); |
| 93 | static void rtl_make_forwarder_block (edge); |
| 94 | |
| 95 | /* Return true if NOTE is not one of the ones that must be kept paired, |
| 96 | so that we may simply delete it. */ |
| 97 | |
| 98 | static int |
| 99 | can_delete_note_p (const_rtx note) |
| 100 | { |
| 101 | switch (NOTE_KIND (note)) |
| 102 | { |
| 103 | case NOTE_INSN_DELETED: |
| 104 | case NOTE_INSN_BASIC_BLOCK: |
| 105 | case NOTE_INSN_EPILOGUE_BEG: |
| 106 | return true; |
| 107 | |
| 108 | default: |
| 109 | return false; |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | /* True if a given label can be deleted. */ |
| 114 | |
| 115 | static int |
| 116 | can_delete_label_p (const_rtx label) |
| 117 | { |
| 118 | return (!LABEL_PRESERVE_P (label) |
| 119 | /* User declared labels must be preserved. */ |
| 120 | && LABEL_NAME (label) == 0 |
| 121 | && !in_expr_list_p (forced_labels, label)); |
| 122 | } |
| 123 | |
| 124 | /* Delete INSN by patching it out. */ |
| 125 | |
| 126 | void |
| 127 | delete_insn (rtx insn) |
| 128 | { |
| 129 | rtx note; |
| 130 | bool really_delete = true; |
| 131 | |
| 132 | if (LABEL_P (insn)) |
| 133 | { |
| 134 | /* Some labels can't be directly removed from the INSN chain, as they |
| 135 | might be references via variables, constant pool etc. |
| 136 | Convert them to the special NOTE_INSN_DELETED_LABEL note. */ |
| 137 | if (! can_delete_label_p (insn)) |
| 138 | { |
| 139 | const char *name = LABEL_NAME (insn); |
| 140 | basic_block bb = BLOCK_FOR_INSN (insn); |
| 141 | rtx bb_note = NEXT_INSN (insn); |
| 142 | |
| 143 | really_delete = false; |
| 144 | PUT_CODE (insn, NOTE); |
| 145 | NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL; |
| 146 | NOTE_DELETED_LABEL_NAME (insn) = name; |
| 147 | |
| 148 | if (bb_note != NULL_RTX && NOTE_INSN_BASIC_BLOCK_P (bb_note) |
| 149 | && BLOCK_FOR_INSN (bb_note) == bb) |
| 150 | { |
| 151 | reorder_insns_nobb (insn, insn, bb_note); |
| 152 | BB_HEAD (bb) = bb_note; |
| 153 | if (BB_END (bb) == bb_note) |
| 154 | BB_END (bb) = insn; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels); |
| 159 | } |
| 160 | |
| 161 | if (really_delete) |
| 162 | { |
| 163 | /* If this insn has already been deleted, something is very wrong. */ |
| 164 | gcc_assert (!INSN_DELETED_P (insn)); |
| 165 | remove_insn (insn); |
| 166 | INSN_DELETED_P (insn) = 1; |
| 167 | } |
| 168 | |
| 169 | /* If deleting a jump, decrement the use count of the label. Deleting |
| 170 | the label itself should happen in the normal course of block merging. */ |
| 171 | if (JUMP_P (insn)) |
| 172 | { |
| 173 | if (JUMP_LABEL (insn) |
| 174 | && LABEL_P (JUMP_LABEL (insn))) |
| 175 | LABEL_NUSES (JUMP_LABEL (insn))--; |
| 176 | |
| 177 | /* If there are more targets, remove them too. */ |
| 178 | while ((note |
| 179 | = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX |
| 180 | && LABEL_P (XEXP (note, 0))) |
| 181 | { |
| 182 | LABEL_NUSES (XEXP (note, 0))--; |
| 183 | remove_note (insn, note); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | /* Also if deleting any insn that references a label as an operand. */ |
| 188 | while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX |
| 189 | && LABEL_P (XEXP (note, 0))) |
| 190 | { |
| 191 | LABEL_NUSES (XEXP (note, 0))--; |
| 192 | remove_note (insn, note); |
| 193 | } |
| 194 | |
| 195 | if (JUMP_TABLE_DATA_P (insn)) |
| 196 | { |
| 197 | rtx pat = PATTERN (insn); |
| 198 | int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC; |
| 199 | int len = XVECLEN (pat, diff_vec_p); |
| 200 | int i; |
| 201 | |
| 202 | for (i = 0; i < len; i++) |
| 203 | { |
| 204 | rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0); |
| 205 | |
| 206 | /* When deleting code in bulk (e.g. removing many unreachable |
| 207 | blocks) we can delete a label that's a target of the vector |
| 208 | before deleting the vector itself. */ |
| 209 | if (!NOTE_P (label)) |
| 210 | LABEL_NUSES (label)--; |
| 211 | } |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | /* Like delete_insn but also purge dead edges from BB. */ |
| 216 | |
| 217 | void |
| 218 | delete_insn_and_edges (rtx insn) |
| 219 | { |
| 220 | bool purge = false; |
| 221 | |
| 222 | if (INSN_P (insn) |
| 223 | && BLOCK_FOR_INSN (insn) |
| 224 | && BB_END (BLOCK_FOR_INSN (insn)) == insn) |
| 225 | purge = true; |
| 226 | delete_insn (insn); |
| 227 | if (purge) |
| 228 | purge_dead_edges (BLOCK_FOR_INSN (insn)); |
| 229 | } |
| 230 | |
| 231 | /* Unlink a chain of insns between START and FINISH, leaving notes |
| 232 | that must be paired. If CLEAR_BB is true, we set bb field for |
| 233 | insns that cannot be removed to NULL. */ |
| 234 | |
| 235 | void |
| 236 | delete_insn_chain (rtx start, rtx finish, bool clear_bb) |
| 237 | { |
| 238 | rtx prev, current; |
| 239 | |
| 240 | /* Unchain the insns one by one. It would be quicker to delete all of these |
| 241 | with a single unchaining, rather than one at a time, but we need to keep |
| 242 | the NOTE's. */ |
| 243 | current = finish; |
| 244 | while (1) |
| 245 | { |
| 246 | prev = PREV_INSN (current); |
| 247 | if (NOTE_P (current) && !can_delete_note_p (current)) |
| 248 | ; |
| 249 | else |
| 250 | delete_insn (current); |
| 251 | |
| 252 | if (clear_bb && !INSN_DELETED_P (current)) |
| 253 | set_block_for_insn (current, NULL); |
| 254 | |
| 255 | if (current == start) |
| 256 | break; |
| 257 | current = prev; |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | /* Create a new basic block consisting of the instructions between HEAD and END |
| 262 | inclusive. This function is designed to allow fast BB construction - reuses |
| 263 | the note and basic block struct in BB_NOTE, if any and do not grow |
| 264 | BASIC_BLOCK chain and should be used directly only by CFG construction code. |
| 265 | END can be NULL in to create new empty basic block before HEAD. Both END |
| 266 | and HEAD can be NULL to create basic block at the end of INSN chain. |
| 267 | AFTER is the basic block we should be put after. */ |
| 268 | |
| 269 | basic_block |
| 270 | create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after) |
| 271 | { |
| 272 | basic_block bb; |
| 273 | |
| 274 | if (bb_note |
| 275 | && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL |
| 276 | && bb->aux == NULL) |
| 277 | { |
| 278 | /* If we found an existing note, thread it back onto the chain. */ |
| 279 | |
| 280 | rtx after; |
| 281 | |
| 282 | if (LABEL_P (head)) |
| 283 | after = head; |
| 284 | else |
| 285 | { |
| 286 | after = PREV_INSN (head); |
| 287 | head = bb_note; |
| 288 | } |
| 289 | |
| 290 | if (after != bb_note && NEXT_INSN (after) != bb_note) |
| 291 | reorder_insns_nobb (bb_note, bb_note, after); |
| 292 | } |
| 293 | else |
| 294 | { |
| 295 | /* Otherwise we must create a note and a basic block structure. */ |
| 296 | |
| 297 | bb = alloc_block (); |
| 298 | |
| 299 | init_rtl_bb_info (bb); |
| 300 | if (!head && !end) |
| 301 | head = end = bb_note |
| 302 | = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ()); |
| 303 | else if (LABEL_P (head) && end) |
| 304 | { |
| 305 | bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head); |
| 306 | if (head == end) |
| 307 | end = bb_note; |
| 308 | } |
| 309 | else |
| 310 | { |
| 311 | bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head); |
| 312 | head = bb_note; |
| 313 | if (!end) |
| 314 | end = head; |
| 315 | } |
| 316 | |
| 317 | NOTE_BASIC_BLOCK (bb_note) = bb; |
| 318 | } |
| 319 | |
| 320 | /* Always include the bb note in the block. */ |
| 321 | if (NEXT_INSN (end) == bb_note) |
| 322 | end = bb_note; |
| 323 | |
| 324 | BB_HEAD (bb) = head; |
| 325 | BB_END (bb) = end; |
| 326 | bb->index = last_basic_block++; |
| 327 | bb->flags = BB_NEW | BB_RTL; |
| 328 | link_block (bb, after); |
| 329 | SET_BASIC_BLOCK (bb->index, bb); |
| 330 | df_bb_refs_record (bb->index, false); |
| 331 | update_bb_for_insn (bb); |
| 332 | BB_SET_PARTITION (bb, BB_UNPARTITIONED); |
| 333 | |
| 334 | /* Tag the block so that we know it has been used when considering |
| 335 | other basic block notes. */ |
| 336 | bb->aux = bb; |
| 337 | |
| 338 | return bb; |
| 339 | } |
| 340 | |
| 341 | /* Create new basic block consisting of instructions in between HEAD and END |
| 342 | and place it to the BB chain after block AFTER. END can be NULL to |
| 343 | create a new empty basic block before HEAD. Both END and HEAD can be |
| 344 | NULL to create basic block at the end of INSN chain. */ |
| 345 | |
| 346 | static basic_block |
| 347 | rtl_create_basic_block (void *headp, void *endp, basic_block after) |
| 348 | { |
| 349 | rtx head = (rtx) headp, end = (rtx) endp; |
| 350 | basic_block bb; |
| 351 | |
| 352 | /* Grow the basic block array if needed. */ |
| 353 | if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info)) |
| 354 | { |
| 355 | size_t new_size = last_basic_block + (last_basic_block + 3) / 4; |
| 356 | VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size); |
| 357 | } |
| 358 | |
| 359 | n_basic_blocks++; |
| 360 | |
| 361 | bb = create_basic_block_structure (head, end, NULL, after); |
| 362 | bb->aux = NULL; |
| 363 | return bb; |
| 364 | } |
| 365 | |
| 366 | static basic_block |
| 367 | cfg_layout_create_basic_block (void *head, void *end, basic_block after) |
| 368 | { |
| 369 | basic_block newbb = rtl_create_basic_block (head, end, after); |
| 370 | |
| 371 | return newbb; |
| 372 | } |
| 373 | |
| 374 | /* Delete the insns in a (non-live) block. We physically delete every |
| 375 | non-deleted-note insn, and update the flow graph appropriately. |
| 376 | |
| 377 | Return nonzero if we deleted an exception handler. */ |
| 378 | |
| 379 | /* ??? Preserving all such notes strikes me as wrong. It would be nice |
| 380 | to post-process the stream to remove empty blocks, loops, ranges, etc. */ |
| 381 | |
| 382 | static void |
| 383 | rtl_delete_block (basic_block b) |
| 384 | { |
| 385 | rtx insn, end; |
| 386 | |
| 387 | /* If the head of this block is a CODE_LABEL, then it might be the |
| 388 | label for an exception handler which can't be reached. We need |
| 389 | to remove the label from the exception_handler_label list. */ |
| 390 | insn = BB_HEAD (b); |
| 391 | |
| 392 | end = get_last_bb_insn (b); |
| 393 | |
| 394 | /* Selectively delete the entire chain. */ |
| 395 | BB_HEAD (b) = NULL; |
| 396 | delete_insn_chain (insn, end, true); |
| 397 | |
| 398 | |
| 399 | if (dump_file) |
| 400 | fprintf (dump_file, "deleting block %d\n", b->index); |
| 401 | df_bb_delete (b->index); |
| 402 | } |
| 403 | |
| 404 | /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */ |
| 405 | |
| 406 | void |
| 407 | compute_bb_for_insn (void) |
| 408 | { |
| 409 | basic_block bb; |
| 410 | |
| 411 | FOR_EACH_BB (bb) |
| 412 | { |
| 413 | rtx end = BB_END (bb); |
| 414 | rtx insn; |
| 415 | |
| 416 | for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn)) |
| 417 | { |
| 418 | BLOCK_FOR_INSN (insn) = bb; |
| 419 | if (insn == end) |
| 420 | break; |
| 421 | } |
| 422 | } |
| 423 | } |
| 424 | |
| 425 | /* Release the basic_block_for_insn array. */ |
| 426 | |
| 427 | unsigned int |
| 428 | free_bb_for_insn (void) |
| 429 | { |
| 430 | rtx insn; |
| 431 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
| 432 | if (!BARRIER_P (insn)) |
| 433 | BLOCK_FOR_INSN (insn) = NULL; |
| 434 | return 0; |
| 435 | } |
| 436 | |
| 437 | static unsigned int |
| 438 | rest_of_pass_free_cfg (void) |
| 439 | { |
| 440 | #ifdef DELAY_SLOTS |
| 441 | /* The resource.c machinery uses DF but the CFG isn't guaranteed to be |
| 442 | valid at that point so it would be too late to call df_analyze. */ |
| 443 | if (optimize > 0 && flag_delayed_branch) |
| 444 | { |
| 445 | df_note_add_problem (); |
| 446 | df_analyze (); |
| 447 | } |
| 448 | #endif |
| 449 | |
| 450 | free_bb_for_insn (); |
| 451 | return 0; |
| 452 | } |
| 453 | |
| 454 | struct rtl_opt_pass pass_free_cfg = |
| 455 | { |
| 456 | { |
| 457 | RTL_PASS, |
| 458 | "*free_cfg", /* name */ |
| 459 | NULL, /* gate */ |
| 460 | rest_of_pass_free_cfg, /* execute */ |
| 461 | NULL, /* sub */ |
| 462 | NULL, /* next */ |
| 463 | 0, /* static_pass_number */ |
| 464 | TV_NONE, /* tv_id */ |
| 465 | 0, /* properties_required */ |
| 466 | 0, /* properties_provided */ |
| 467 | PROP_cfg, /* properties_destroyed */ |
| 468 | 0, /* todo_flags_start */ |
| 469 | 0, /* todo_flags_finish */ |
| 470 | } |
| 471 | }; |
| 472 | |
| 473 | /* Return RTX to emit after when we want to emit code on the entry of function. */ |
| 474 | rtx |
| 475 | entry_of_function (void) |
| 476 | { |
| 477 | return (n_basic_blocks > NUM_FIXED_BLOCKS ? |
| 478 | BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ()); |
| 479 | } |
| 480 | |
| 481 | /* Emit INSN at the entry point of the function, ensuring that it is only |
| 482 | executed once per function. */ |
| 483 | void |
| 484 | emit_insn_at_entry (rtx insn) |
| 485 | { |
| 486 | edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs); |
| 487 | edge e = ei_safe_edge (ei); |
| 488 | gcc_assert (e->flags & EDGE_FALLTHRU); |
| 489 | |
| 490 | insert_insn_on_edge (insn, e); |
| 491 | commit_edge_insertions (); |
| 492 | } |
| 493 | |
| 494 | /* Update BLOCK_FOR_INSN of insns between BEGIN and END |
| 495 | (or BARRIER if found) and notify df of the bb change. |
| 496 | The insn chain range is inclusive |
| 497 | (i.e. both BEGIN and END will be updated. */ |
| 498 | |
| 499 | static void |
| 500 | update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb) |
| 501 | { |
| 502 | rtx insn; |
| 503 | |
| 504 | end = NEXT_INSN (end); |
| 505 | for (insn = begin; insn != end; insn = NEXT_INSN (insn)) |
| 506 | if (!BARRIER_P (insn)) |
| 507 | df_insn_change_bb (insn, bb); |
| 508 | } |
| 509 | |
| 510 | /* Update BLOCK_FOR_INSN of insns in BB to BB, |
| 511 | and notify df of the change. */ |
| 512 | |
| 513 | void |
| 514 | update_bb_for_insn (basic_block bb) |
| 515 | { |
| 516 | update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb); |
| 517 | } |
| 518 | |
| 519 | |
| 520 | /* Like active_insn_p, except keep the return value clobber around |
| 521 | even after reload. */ |
| 522 | |
| 523 | static bool |
| 524 | flow_active_insn_p (const_rtx insn) |
| 525 | { |
| 526 | if (active_insn_p (insn)) |
| 527 | return true; |
| 528 | |
| 529 | /* A clobber of the function return value exists for buggy |
| 530 | programs that fail to return a value. Its effect is to |
| 531 | keep the return value from being live across the entire |
| 532 | function. If we allow it to be skipped, we introduce the |
| 533 | possibility for register lifetime confusion. */ |
| 534 | if (GET_CODE (PATTERN (insn)) == CLOBBER |
| 535 | && REG_P (XEXP (PATTERN (insn), 0)) |
| 536 | && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0))) |
| 537 | return true; |
| 538 | |
| 539 | return false; |
| 540 | } |
| 541 | |
| 542 | /* Return true if the block has no effect and only forwards control flow to |
| 543 | its single destination. */ |
| 544 | /* FIXME: Make this a cfg hook. */ |
| 545 | |
| 546 | bool |
| 547 | forwarder_block_p (const_basic_block bb) |
| 548 | { |
| 549 | rtx insn; |
| 550 | |
| 551 | if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR |
| 552 | || !single_succ_p (bb)) |
| 553 | return false; |
| 554 | |
| 555 | /* Protect loop latches, headers and preheaders. */ |
| 556 | if (current_loops) |
| 557 | { |
| 558 | basic_block dest; |
| 559 | if (bb->loop_father->header == bb) |
| 560 | return false; |
| 561 | dest = EDGE_SUCC (bb, 0)->dest; |
| 562 | if (dest->loop_father->header == dest) |
| 563 | return false; |
| 564 | } |
| 565 | |
| 566 | for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn)) |
| 567 | if (INSN_P (insn) && flow_active_insn_p (insn)) |
| 568 | return false; |
| 569 | |
| 570 | return (!INSN_P (insn) |
| 571 | || (JUMP_P (insn) && simplejump_p (insn)) |
| 572 | || !flow_active_insn_p (insn)); |
| 573 | } |
| 574 | |
| 575 | /* Return nonzero if we can reach target from src by falling through. */ |
| 576 | /* FIXME: Make this a cfg hook. */ |
| 577 | |
| 578 | bool |
| 579 | can_fallthru (basic_block src, basic_block target) |
| 580 | { |
| 581 | rtx insn = BB_END (src); |
| 582 | rtx insn2; |
| 583 | edge e; |
| 584 | edge_iterator ei; |
| 585 | |
| 586 | if (target == EXIT_BLOCK_PTR) |
| 587 | return true; |
| 588 | if (src->next_bb != target) |
| 589 | return 0; |
| 590 | FOR_EACH_EDGE (e, ei, src->succs) |
| 591 | if (e->dest == EXIT_BLOCK_PTR |
| 592 | && e->flags & EDGE_FALLTHRU) |
| 593 | return 0; |
| 594 | |
| 595 | insn2 = BB_HEAD (target); |
| 596 | if (insn2 && !active_insn_p (insn2)) |
| 597 | insn2 = next_active_insn (insn2); |
| 598 | |
| 599 | /* ??? Later we may add code to move jump tables offline. */ |
| 600 | return next_active_insn (insn) == insn2; |
| 601 | } |
| 602 | |
| 603 | /* Return nonzero if we could reach target from src by falling through, |
| 604 | if the target was made adjacent. If we already have a fall-through |
| 605 | edge to the exit block, we can't do that. */ |
| 606 | static bool |
| 607 | could_fall_through (basic_block src, basic_block target) |
| 608 | { |
| 609 | edge e; |
| 610 | edge_iterator ei; |
| 611 | |
| 612 | if (target == EXIT_BLOCK_PTR) |
| 613 | return true; |
| 614 | FOR_EACH_EDGE (e, ei, src->succs) |
| 615 | if (e->dest == EXIT_BLOCK_PTR |
| 616 | && e->flags & EDGE_FALLTHRU) |
| 617 | return 0; |
| 618 | return true; |
| 619 | } |
| 620 | |
| 621 | /* Return the NOTE_INSN_BASIC_BLOCK of BB. */ |
| 622 | rtx |
| 623 | bb_note (basic_block bb) |
| 624 | { |
| 625 | rtx note; |
| 626 | |
| 627 | note = BB_HEAD (bb); |
| 628 | if (LABEL_P (note)) |
| 629 | note = NEXT_INSN (note); |
| 630 | |
| 631 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note)); |
| 632 | return note; |
| 633 | } |
| 634 | |
| 635 | /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK |
| 636 | note associated with the BLOCK. */ |
| 637 | |
| 638 | static rtx |
| 639 | first_insn_after_basic_block_note (basic_block block) |
| 640 | { |
| 641 | rtx insn; |
| 642 | |
| 643 | /* Get the first instruction in the block. */ |
| 644 | insn = BB_HEAD (block); |
| 645 | |
| 646 | if (insn == NULL_RTX) |
| 647 | return NULL_RTX; |
| 648 | if (LABEL_P (insn)) |
| 649 | insn = NEXT_INSN (insn); |
| 650 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn)); |
| 651 | |
| 652 | return NEXT_INSN (insn); |
| 653 | } |
| 654 | |
| 655 | /* Creates a new basic block just after basic block B by splitting |
| 656 | everything after specified instruction I. */ |
| 657 | |
| 658 | static basic_block |
| 659 | rtl_split_block (basic_block bb, void *insnp) |
| 660 | { |
| 661 | basic_block new_bb; |
| 662 | rtx insn = (rtx) insnp; |
| 663 | edge e; |
| 664 | edge_iterator ei; |
| 665 | |
| 666 | if (!insn) |
| 667 | { |
| 668 | insn = first_insn_after_basic_block_note (bb); |
| 669 | |
| 670 | if (insn) |
| 671 | { |
| 672 | rtx next = insn; |
| 673 | |
| 674 | insn = PREV_INSN (insn); |
| 675 | |
| 676 | /* If the block contains only debug insns, insn would have |
| 677 | been NULL in a non-debug compilation, and then we'd end |
| 678 | up emitting a DELETED note. For -fcompare-debug |
| 679 | stability, emit the note too. */ |
| 680 | if (insn != BB_END (bb) |
| 681 | && DEBUG_INSN_P (next) |
| 682 | && DEBUG_INSN_P (BB_END (bb))) |
| 683 | { |
| 684 | while (next != BB_END (bb) && DEBUG_INSN_P (next)) |
| 685 | next = NEXT_INSN (next); |
| 686 | |
| 687 | if (next == BB_END (bb)) |
| 688 | emit_note_after (NOTE_INSN_DELETED, next); |
| 689 | } |
| 690 | } |
| 691 | else |
| 692 | insn = get_last_insn (); |
| 693 | } |
| 694 | |
| 695 | /* We probably should check type of the insn so that we do not create |
| 696 | inconsistent cfg. It is checked in verify_flow_info anyway, so do not |
| 697 | bother. */ |
| 698 | if (insn == BB_END (bb)) |
| 699 | emit_note_after (NOTE_INSN_DELETED, insn); |
| 700 | |
| 701 | /* Create the new basic block. */ |
| 702 | new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb); |
| 703 | BB_COPY_PARTITION (new_bb, bb); |
| 704 | BB_END (bb) = insn; |
| 705 | |
| 706 | /* Redirect the outgoing edges. */ |
| 707 | new_bb->succs = bb->succs; |
| 708 | bb->succs = NULL; |
| 709 | FOR_EACH_EDGE (e, ei, new_bb->succs) |
| 710 | e->src = new_bb; |
| 711 | |
| 712 | /* The new block starts off being dirty. */ |
| 713 | df_set_bb_dirty (bb); |
| 714 | return new_bb; |
| 715 | } |
| 716 | |
| 717 | /* Return true if the single edge between blocks A and B is the only place |
| 718 | in RTL which holds some unique locus. */ |
| 719 | |
| 720 | static bool |
| 721 | unique_locus_on_edge_between_p (basic_block a, basic_block b) |
| 722 | { |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 723 | const location_t goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 724 | rtx insn, end; |
| 725 | |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 726 | if (IS_UNKNOWN_LOCATION (goto_locus)) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 727 | return false; |
| 728 | |
| 729 | /* First scan block A backward. */ |
| 730 | insn = BB_END (a); |
| 731 | end = PREV_INSN (BB_HEAD (a)); |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 732 | while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn))) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 733 | insn = PREV_INSN (insn); |
| 734 | |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 735 | if (insn != end && INSN_LOCATION (insn) == goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 736 | return false; |
| 737 | |
| 738 | /* Then scan block B forward. */ |
| 739 | insn = BB_HEAD (b); |
| 740 | if (insn) |
| 741 | { |
| 742 | end = NEXT_INSN (BB_END (b)); |
| 743 | while (insn != end && !NONDEBUG_INSN_P (insn)) |
| 744 | insn = NEXT_INSN (insn); |
| 745 | |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 746 | if (insn != end && INSN_HAS_LOCATION (insn) |
| 747 | && INSN_LOCATION (insn) == goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 748 | return false; |
| 749 | } |
| 750 | |
| 751 | return true; |
| 752 | } |
| 753 | |
| 754 | /* If the single edge between blocks A and B is the only place in RTL which |
| 755 | holds some unique locus, emit a nop with that locus between the blocks. */ |
| 756 | |
| 757 | static void |
| 758 | emit_nop_for_unique_locus_between (basic_block a, basic_block b) |
| 759 | { |
| 760 | if (!unique_locus_on_edge_between_p (a, b)) |
| 761 | return; |
| 762 | |
| 763 | BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a); |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 764 | INSN_LOCATION (BB_END (a)) = EDGE_SUCC (a, 0)->goto_locus; |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 765 | } |
| 766 | |
| 767 | /* Blocks A and B are to be merged into a single block A. The insns |
| 768 | are already contiguous. */ |
| 769 | |
| 770 | static void |
| 771 | rtl_merge_blocks (basic_block a, basic_block b) |
| 772 | { |
| 773 | rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a); |
| 774 | rtx del_first = NULL_RTX, del_last = NULL_RTX; |
| 775 | rtx b_debug_start = b_end, b_debug_end = b_end; |
| 776 | bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0; |
| 777 | int b_empty = 0; |
| 778 | |
| 779 | if (dump_file) |
| 780 | fprintf (dump_file, "Merging block %d into block %d...\n", b->index, |
| 781 | a->index); |
| 782 | |
| 783 | while (DEBUG_INSN_P (b_end)) |
| 784 | b_end = PREV_INSN (b_debug_start = b_end); |
| 785 | |
| 786 | /* If there was a CODE_LABEL beginning B, delete it. */ |
| 787 | if (LABEL_P (b_head)) |
| 788 | { |
| 789 | /* Detect basic blocks with nothing but a label. This can happen |
| 790 | in particular at the end of a function. */ |
| 791 | if (b_head == b_end) |
| 792 | b_empty = 1; |
| 793 | |
| 794 | del_first = del_last = b_head; |
| 795 | b_head = NEXT_INSN (b_head); |
| 796 | } |
| 797 | |
| 798 | /* Delete the basic block note and handle blocks containing just that |
| 799 | note. */ |
| 800 | if (NOTE_INSN_BASIC_BLOCK_P (b_head)) |
| 801 | { |
| 802 | if (b_head == b_end) |
| 803 | b_empty = 1; |
| 804 | if (! del_last) |
| 805 | del_first = b_head; |
| 806 | |
| 807 | del_last = b_head; |
| 808 | b_head = NEXT_INSN (b_head); |
| 809 | } |
| 810 | |
| 811 | /* If there was a jump out of A, delete it. */ |
| 812 | if (JUMP_P (a_end)) |
| 813 | { |
| 814 | rtx prev; |
| 815 | |
| 816 | for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev)) |
| 817 | if (!NOTE_P (prev) |
| 818 | || NOTE_INSN_BASIC_BLOCK_P (prev) |
| 819 | || prev == BB_HEAD (a)) |
| 820 | break; |
| 821 | |
| 822 | del_first = a_end; |
| 823 | |
| 824 | #ifdef HAVE_cc0 |
| 825 | /* If this was a conditional jump, we need to also delete |
| 826 | the insn that set cc0. */ |
| 827 | if (only_sets_cc0_p (prev)) |
| 828 | { |
| 829 | rtx tmp = prev; |
| 830 | |
| 831 | prev = prev_nonnote_insn (prev); |
| 832 | if (!prev) |
| 833 | prev = BB_HEAD (a); |
| 834 | del_first = tmp; |
| 835 | } |
| 836 | #endif |
| 837 | |
| 838 | a_end = PREV_INSN (del_first); |
| 839 | } |
| 840 | else if (BARRIER_P (NEXT_INSN (a_end))) |
| 841 | del_first = NEXT_INSN (a_end); |
| 842 | |
| 843 | /* Delete everything marked above as well as crap that might be |
| 844 | hanging out between the two blocks. */ |
| 845 | BB_END (a) = a_end; |
| 846 | BB_HEAD (b) = b_empty ? NULL_RTX : b_head; |
| 847 | delete_insn_chain (del_first, del_last, true); |
| 848 | |
| 849 | /* When not optimizing CFG and the edge is the only place in RTL which holds |
| 850 | some unique locus, emit a nop with that locus in between. */ |
| 851 | if (!optimize) |
| 852 | { |
| 853 | emit_nop_for_unique_locus_between (a, b); |
| 854 | a_end = BB_END (a); |
| 855 | } |
| 856 | |
| 857 | /* Reassociate the insns of B with A. */ |
| 858 | if (!b_empty) |
| 859 | { |
| 860 | update_bb_for_insn_chain (a_end, b_debug_end, a); |
| 861 | |
| 862 | BB_END (a) = b_debug_end; |
| 863 | BB_HEAD (b) = NULL_RTX; |
| 864 | } |
| 865 | else if (b_end != b_debug_end) |
| 866 | { |
| 867 | /* Move any deleted labels and other notes between the end of A |
| 868 | and the debug insns that make up B after the debug insns, |
| 869 | bringing the debug insns into A while keeping the notes after |
| 870 | the end of A. */ |
| 871 | if (NEXT_INSN (a_end) != b_debug_start) |
| 872 | reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start), |
| 873 | b_debug_end); |
| 874 | update_bb_for_insn_chain (b_debug_start, b_debug_end, a); |
| 875 | BB_END (a) = b_debug_end; |
| 876 | } |
| 877 | |
| 878 | df_bb_delete (b->index); |
| 879 | |
| 880 | /* If B was a forwarder block, propagate the locus on the edge. */ |
| 881 | if (forwarder_p && !EDGE_SUCC (b, 0)->goto_locus) |
| 882 | EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
| 883 | |
| 884 | if (dump_file) |
| 885 | fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index); |
| 886 | } |
| 887 | |
| 888 | |
| 889 | /* Return true when block A and B can be merged. */ |
| 890 | |
| 891 | static bool |
| 892 | rtl_can_merge_blocks (basic_block a, basic_block b) |
| 893 | { |
| 894 | /* If we are partitioning hot/cold basic blocks, we don't want to |
| 895 | mess up unconditional or indirect jumps that cross between hot |
| 896 | and cold sections. |
| 897 | |
| 898 | Basic block partitioning may result in some jumps that appear to |
| 899 | be optimizable (or blocks that appear to be mergeable), but which really |
| 900 | must be left untouched (they are required to make it safely across |
| 901 | partition boundaries). See the comments at the top of |
| 902 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
| 903 | |
| 904 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
| 905 | return false; |
| 906 | |
| 907 | /* Protect the loop latches. */ |
| 908 | if (current_loops && b->loop_father->latch == b) |
| 909 | return false; |
| 910 | |
| 911 | /* There must be exactly one edge in between the blocks. */ |
| 912 | return (single_succ_p (a) |
| 913 | && single_succ (a) == b |
| 914 | && single_pred_p (b) |
| 915 | && a != b |
| 916 | /* Must be simple edge. */ |
| 917 | && !(single_succ_edge (a)->flags & EDGE_COMPLEX) |
| 918 | && a->next_bb == b |
| 919 | && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR |
| 920 | /* If the jump insn has side effects, |
| 921 | we can't kill the edge. */ |
| 922 | && (!JUMP_P (BB_END (a)) |
| 923 | || (reload_completed |
| 924 | ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a))))); |
| 925 | } |
| 926 | |
| 927 | /* Return the label in the head of basic block BLOCK. Create one if it doesn't |
| 928 | exist. */ |
| 929 | |
| 930 | rtx |
| 931 | block_label (basic_block block) |
| 932 | { |
| 933 | if (block == EXIT_BLOCK_PTR) |
| 934 | return NULL_RTX; |
| 935 | |
| 936 | if (!LABEL_P (BB_HEAD (block))) |
| 937 | { |
| 938 | BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block)); |
| 939 | } |
| 940 | |
| 941 | return BB_HEAD (block); |
| 942 | } |
| 943 | |
| 944 | /* Attempt to perform edge redirection by replacing possibly complex jump |
| 945 | instruction by unconditional jump or removing jump completely. This can |
| 946 | apply only if all edges now point to the same block. The parameters and |
| 947 | return values are equivalent to redirect_edge_and_branch. */ |
| 948 | |
| 949 | edge |
| 950 | try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout) |
| 951 | { |
| 952 | basic_block src = e->src; |
| 953 | rtx insn = BB_END (src), kill_from; |
| 954 | rtx set; |
| 955 | int fallthru = 0; |
| 956 | |
| 957 | /* If we are partitioning hot/cold basic blocks, we don't want to |
| 958 | mess up unconditional or indirect jumps that cross between hot |
| 959 | and cold sections. |
| 960 | |
| 961 | Basic block partitioning may result in some jumps that appear to |
| 962 | be optimizable (or blocks that appear to be mergeable), but which really |
| 963 | must be left untouched (they are required to make it safely across |
| 964 | partition boundaries). See the comments at the top of |
| 965 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
| 966 | |
| 967 | if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) |
| 968 | || BB_PARTITION (src) != BB_PARTITION (target)) |
| 969 | return NULL; |
| 970 | |
| 971 | /* We can replace or remove a complex jump only when we have exactly |
| 972 | two edges. Also, if we have exactly one outgoing edge, we can |
| 973 | redirect that. */ |
| 974 | if (EDGE_COUNT (src->succs) >= 3 |
| 975 | /* Verify that all targets will be TARGET. Specifically, the |
| 976 | edge that is not E must also go to TARGET. */ |
| 977 | || (EDGE_COUNT (src->succs) == 2 |
| 978 | && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)) |
| 979 | return NULL; |
| 980 | |
| 981 | if (!onlyjump_p (insn)) |
| 982 | return NULL; |
| 983 | if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL)) |
| 984 | return NULL; |
| 985 | |
| 986 | /* Avoid removing branch with side effects. */ |
| 987 | set = single_set (insn); |
| 988 | if (!set || side_effects_p (set)) |
| 989 | return NULL; |
| 990 | |
| 991 | /* In case we zap a conditional jump, we'll need to kill |
| 992 | the cc0 setter too. */ |
| 993 | kill_from = insn; |
| 994 | #ifdef HAVE_cc0 |
| 995 | if (reg_mentioned_p (cc0_rtx, PATTERN (insn)) |
| 996 | && only_sets_cc0_p (PREV_INSN (insn))) |
| 997 | kill_from = PREV_INSN (insn); |
| 998 | #endif |
| 999 | |
| 1000 | /* See if we can create the fallthru edge. */ |
| 1001 | if (in_cfglayout || can_fallthru (src, target)) |
| 1002 | { |
| 1003 | if (dump_file) |
| 1004 | fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn)); |
| 1005 | fallthru = 1; |
| 1006 | |
| 1007 | /* Selectively unlink whole insn chain. */ |
| 1008 | if (in_cfglayout) |
| 1009 | { |
| 1010 | rtx insn = BB_FOOTER (src); |
| 1011 | |
| 1012 | delete_insn_chain (kill_from, BB_END (src), false); |
| 1013 | |
| 1014 | /* Remove barriers but keep jumptables. */ |
| 1015 | while (insn) |
| 1016 | { |
| 1017 | if (BARRIER_P (insn)) |
| 1018 | { |
| 1019 | if (PREV_INSN (insn)) |
| 1020 | NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); |
| 1021 | else |
| 1022 | BB_FOOTER (src) = NEXT_INSN (insn); |
| 1023 | if (NEXT_INSN (insn)) |
| 1024 | PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); |
| 1025 | } |
| 1026 | if (LABEL_P (insn)) |
| 1027 | break; |
| 1028 | insn = NEXT_INSN (insn); |
| 1029 | } |
| 1030 | } |
| 1031 | else |
| 1032 | delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)), |
| 1033 | false); |
| 1034 | } |
| 1035 | |
| 1036 | /* If this already is simplejump, redirect it. */ |
| 1037 | else if (simplejump_p (insn)) |
| 1038 | { |
| 1039 | if (e->dest == target) |
| 1040 | return NULL; |
| 1041 | if (dump_file) |
| 1042 | fprintf (dump_file, "Redirecting jump %i from %i to %i.\n", |
| 1043 | INSN_UID (insn), e->dest->index, target->index); |
| 1044 | if (!redirect_jump (insn, block_label (target), 0)) |
| 1045 | { |
| 1046 | gcc_assert (target == EXIT_BLOCK_PTR); |
| 1047 | return NULL; |
| 1048 | } |
| 1049 | } |
| 1050 | |
| 1051 | /* Cannot do anything for target exit block. */ |
| 1052 | else if (target == EXIT_BLOCK_PTR) |
| 1053 | return NULL; |
| 1054 | |
| 1055 | /* Or replace possibly complicated jump insn by simple jump insn. */ |
| 1056 | else |
| 1057 | { |
| 1058 | rtx target_label = block_label (target); |
| 1059 | rtx barrier, label, table; |
| 1060 | |
| 1061 | emit_jump_insn_after_noloc (gen_jump (target_label), insn); |
| 1062 | JUMP_LABEL (BB_END (src)) = target_label; |
| 1063 | LABEL_NUSES (target_label)++; |
| 1064 | if (dump_file) |
| 1065 | fprintf (dump_file, "Replacing insn %i by jump %i\n", |
| 1066 | INSN_UID (insn), INSN_UID (BB_END (src))); |
| 1067 | |
| 1068 | |
| 1069 | delete_insn_chain (kill_from, insn, false); |
| 1070 | |
| 1071 | /* Recognize a tablejump that we are converting to a |
| 1072 | simple jump and remove its associated CODE_LABEL |
| 1073 | and ADDR_VEC or ADDR_DIFF_VEC. */ |
| 1074 | if (tablejump_p (insn, &label, &table)) |
| 1075 | delete_insn_chain (label, table, false); |
| 1076 | |
| 1077 | barrier = next_nonnote_insn (BB_END (src)); |
| 1078 | if (!barrier || !BARRIER_P (barrier)) |
| 1079 | emit_barrier_after (BB_END (src)); |
| 1080 | else |
| 1081 | { |
| 1082 | if (barrier != NEXT_INSN (BB_END (src))) |
| 1083 | { |
| 1084 | /* Move the jump before barrier so that the notes |
| 1085 | which originally were or were created before jump table are |
| 1086 | inside the basic block. */ |
| 1087 | rtx new_insn = BB_END (src); |
| 1088 | |
| 1089 | update_bb_for_insn_chain (NEXT_INSN (BB_END (src)), |
| 1090 | PREV_INSN (barrier), src); |
| 1091 | |
| 1092 | NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn); |
| 1093 | PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn); |
| 1094 | |
| 1095 | NEXT_INSN (new_insn) = barrier; |
| 1096 | NEXT_INSN (PREV_INSN (barrier)) = new_insn; |
| 1097 | |
| 1098 | PREV_INSN (new_insn) = PREV_INSN (barrier); |
| 1099 | PREV_INSN (barrier) = new_insn; |
| 1100 | } |
| 1101 | } |
| 1102 | } |
| 1103 | |
| 1104 | /* Keep only one edge out and set proper flags. */ |
| 1105 | if (!single_succ_p (src)) |
| 1106 | remove_edge (e); |
| 1107 | gcc_assert (single_succ_p (src)); |
| 1108 | |
| 1109 | e = single_succ_edge (src); |
| 1110 | if (fallthru) |
| 1111 | e->flags = EDGE_FALLTHRU; |
| 1112 | else |
| 1113 | e->flags = 0; |
| 1114 | |
| 1115 | e->probability = REG_BR_PROB_BASE; |
| 1116 | e->count = src->count; |
| 1117 | |
| 1118 | if (e->dest != target) |
| 1119 | redirect_edge_succ (e, target); |
| 1120 | return e; |
| 1121 | } |
| 1122 | |
| 1123 | /* Subroutine of redirect_branch_edge that tries to patch the jump |
| 1124 | instruction INSN so that it reaches block NEW. Do this |
| 1125 | only when it originally reached block OLD. Return true if this |
| 1126 | worked or the original target wasn't OLD, return false if redirection |
| 1127 | doesn't work. */ |
| 1128 | |
| 1129 | static bool |
| 1130 | patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb) |
| 1131 | { |
| 1132 | rtx tmp; |
| 1133 | /* Recognize a tablejump and adjust all matching cases. */ |
| 1134 | if (tablejump_p (insn, NULL, &tmp)) |
| 1135 | { |
| 1136 | rtvec vec; |
| 1137 | int j; |
| 1138 | rtx new_label = block_label (new_bb); |
| 1139 | |
| 1140 | if (new_bb == EXIT_BLOCK_PTR) |
| 1141 | return false; |
| 1142 | if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) |
| 1143 | vec = XVEC (PATTERN (tmp), 0); |
| 1144 | else |
| 1145 | vec = XVEC (PATTERN (tmp), 1); |
| 1146 | |
| 1147 | for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) |
| 1148 | if (XEXP (RTVEC_ELT (vec, j), 0) == old_label) |
| 1149 | { |
| 1150 | RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label); |
| 1151 | --LABEL_NUSES (old_label); |
| 1152 | ++LABEL_NUSES (new_label); |
| 1153 | } |
| 1154 | |
| 1155 | /* Handle casesi dispatch insns. */ |
| 1156 | if ((tmp = single_set (insn)) != NULL |
| 1157 | && SET_DEST (tmp) == pc_rtx |
| 1158 | && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE |
| 1159 | && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF |
| 1160 | && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label) |
| 1161 | { |
| 1162 | XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode, |
| 1163 | new_label); |
| 1164 | --LABEL_NUSES (old_label); |
| 1165 | ++LABEL_NUSES (new_label); |
| 1166 | } |
| 1167 | } |
| 1168 | else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL) |
| 1169 | { |
| 1170 | int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp); |
| 1171 | rtx new_label, note; |
| 1172 | |
| 1173 | if (new_bb == EXIT_BLOCK_PTR) |
| 1174 | return false; |
| 1175 | new_label = block_label (new_bb); |
| 1176 | |
| 1177 | for (i = 0; i < n; ++i) |
| 1178 | { |
| 1179 | rtx old_ref = ASM_OPERANDS_LABEL (tmp, i); |
| 1180 | gcc_assert (GET_CODE (old_ref) == LABEL_REF); |
| 1181 | if (XEXP (old_ref, 0) == old_label) |
| 1182 | { |
| 1183 | ASM_OPERANDS_LABEL (tmp, i) |
| 1184 | = gen_rtx_LABEL_REF (Pmode, new_label); |
| 1185 | --LABEL_NUSES (old_label); |
| 1186 | ++LABEL_NUSES (new_label); |
| 1187 | } |
| 1188 | } |
| 1189 | |
| 1190 | if (JUMP_LABEL (insn) == old_label) |
| 1191 | { |
| 1192 | JUMP_LABEL (insn) = new_label; |
| 1193 | note = find_reg_note (insn, REG_LABEL_TARGET, new_label); |
| 1194 | if (note) |
| 1195 | remove_note (insn, note); |
| 1196 | } |
| 1197 | else |
| 1198 | { |
| 1199 | note = find_reg_note (insn, REG_LABEL_TARGET, old_label); |
| 1200 | if (note) |
| 1201 | remove_note (insn, note); |
| 1202 | if (JUMP_LABEL (insn) != new_label |
| 1203 | && !find_reg_note (insn, REG_LABEL_TARGET, new_label)) |
| 1204 | add_reg_note (insn, REG_LABEL_TARGET, new_label); |
| 1205 | } |
| 1206 | while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label)) |
| 1207 | != NULL_RTX) |
| 1208 | XEXP (note, 0) = new_label; |
| 1209 | } |
| 1210 | else |
| 1211 | { |
| 1212 | /* ?? We may play the games with moving the named labels from |
| 1213 | one basic block to the other in case only one computed_jump is |
| 1214 | available. */ |
| 1215 | if (computed_jump_p (insn) |
| 1216 | /* A return instruction can't be redirected. */ |
| 1217 | || returnjump_p (insn)) |
| 1218 | return false; |
| 1219 | |
| 1220 | if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label) |
| 1221 | { |
| 1222 | /* If the insn doesn't go where we think, we're confused. */ |
| 1223 | gcc_assert (JUMP_LABEL (insn) == old_label); |
| 1224 | |
| 1225 | /* If the substitution doesn't succeed, die. This can happen |
| 1226 | if the back end emitted unrecognizable instructions or if |
| 1227 | target is exit block on some arches. */ |
| 1228 | if (!redirect_jump (insn, block_label (new_bb), 0)) |
| 1229 | { |
| 1230 | gcc_assert (new_bb == EXIT_BLOCK_PTR); |
| 1231 | return false; |
| 1232 | } |
| 1233 | } |
| 1234 | } |
| 1235 | return true; |
| 1236 | } |
| 1237 | |
| 1238 | |
| 1239 | /* Redirect edge representing branch of (un)conditional jump or tablejump, |
| 1240 | NULL on failure */ |
| 1241 | static edge |
| 1242 | redirect_branch_edge (edge e, basic_block target) |
| 1243 | { |
| 1244 | rtx old_label = BB_HEAD (e->dest); |
| 1245 | basic_block src = e->src; |
| 1246 | rtx insn = BB_END (src); |
| 1247 | |
| 1248 | /* We can only redirect non-fallthru edges of jump insn. */ |
| 1249 | if (e->flags & EDGE_FALLTHRU) |
| 1250 | return NULL; |
| 1251 | else if (!JUMP_P (insn) && !currently_expanding_to_rtl) |
| 1252 | return NULL; |
| 1253 | |
| 1254 | if (!currently_expanding_to_rtl) |
| 1255 | { |
| 1256 | if (!patch_jump_insn (insn, old_label, target)) |
| 1257 | return NULL; |
| 1258 | } |
| 1259 | else |
| 1260 | /* When expanding this BB might actually contain multiple |
| 1261 | jumps (i.e. not yet split by find_many_sub_basic_blocks). |
| 1262 | Redirect all of those that match our label. */ |
| 1263 | FOR_BB_INSNS (src, insn) |
| 1264 | if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target)) |
| 1265 | return NULL; |
| 1266 | |
| 1267 | if (dump_file) |
| 1268 | fprintf (dump_file, "Edge %i->%i redirected to %i\n", |
| 1269 | e->src->index, e->dest->index, target->index); |
| 1270 | |
| 1271 | if (e->dest != target) |
| 1272 | e = redirect_edge_succ_nodup (e, target); |
| 1273 | |
| 1274 | return e; |
| 1275 | } |
| 1276 | |
| 1277 | /* Attempt to change code to redirect edge E to TARGET. Don't do that on |
| 1278 | expense of adding new instructions or reordering basic blocks. |
| 1279 | |
| 1280 | Function can be also called with edge destination equivalent to the TARGET. |
| 1281 | Then it should try the simplifications and do nothing if none is possible. |
| 1282 | |
| 1283 | Return edge representing the branch if transformation succeeded. Return NULL |
| 1284 | on failure. |
| 1285 | We still return NULL in case E already destinated TARGET and we didn't |
| 1286 | managed to simplify instruction stream. */ |
| 1287 | |
| 1288 | static edge |
| 1289 | rtl_redirect_edge_and_branch (edge e, basic_block target) |
| 1290 | { |
| 1291 | edge ret; |
| 1292 | basic_block src = e->src; |
| 1293 | |
| 1294 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
| 1295 | return NULL; |
| 1296 | |
| 1297 | if (e->dest == target) |
| 1298 | return e; |
| 1299 | |
| 1300 | if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL) |
| 1301 | { |
| 1302 | df_set_bb_dirty (src); |
| 1303 | return ret; |
| 1304 | } |
| 1305 | |
| 1306 | ret = redirect_branch_edge (e, target); |
| 1307 | if (!ret) |
| 1308 | return NULL; |
| 1309 | |
| 1310 | df_set_bb_dirty (src); |
| 1311 | return ret; |
| 1312 | } |
| 1313 | |
| 1314 | /* Like force_nonfallthru below, but additionally performs redirection |
| 1315 | Used by redirect_edge_and_branch_force. JUMP_LABEL is used only |
| 1316 | when redirecting to the EXIT_BLOCK, it is either ret_rtx or |
| 1317 | simple_return_rtx, indicating which kind of returnjump to create. |
| 1318 | It should be NULL otherwise. */ |
| 1319 | |
| 1320 | basic_block |
| 1321 | force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label) |
| 1322 | { |
| 1323 | basic_block jump_block, new_bb = NULL, src = e->src; |
| 1324 | rtx note; |
| 1325 | edge new_edge; |
| 1326 | int abnormal_edge_flags = 0; |
| 1327 | bool asm_goto_edge = false; |
| 1328 | int loc; |
| 1329 | |
| 1330 | /* In the case the last instruction is conditional jump to the next |
| 1331 | instruction, first redirect the jump itself and then continue |
| 1332 | by creating a basic block afterwards to redirect fallthru edge. */ |
| 1333 | if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR |
| 1334 | && any_condjump_p (BB_END (e->src)) |
| 1335 | && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest)) |
| 1336 | { |
| 1337 | rtx note; |
| 1338 | edge b = unchecked_make_edge (e->src, target, 0); |
| 1339 | bool redirected; |
| 1340 | |
| 1341 | redirected = redirect_jump (BB_END (e->src), block_label (target), 0); |
| 1342 | gcc_assert (redirected); |
| 1343 | |
| 1344 | note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX); |
| 1345 | if (note) |
| 1346 | { |
| 1347 | int prob = INTVAL (XEXP (note, 0)); |
| 1348 | |
| 1349 | b->probability = prob; |
| 1350 | b->count = e->count * prob / REG_BR_PROB_BASE; |
| 1351 | e->probability -= e->probability; |
| 1352 | e->count -= b->count; |
| 1353 | if (e->probability < 0) |
| 1354 | e->probability = 0; |
| 1355 | if (e->count < 0) |
| 1356 | e->count = 0; |
| 1357 | } |
| 1358 | } |
| 1359 | |
| 1360 | if (e->flags & EDGE_ABNORMAL) |
| 1361 | { |
| 1362 | /* Irritating special case - fallthru edge to the same block as abnormal |
| 1363 | edge. |
| 1364 | We can't redirect abnormal edge, but we still can split the fallthru |
| 1365 | one and create separate abnormal edge to original destination. |
| 1366 | This allows bb-reorder to make such edge non-fallthru. */ |
| 1367 | gcc_assert (e->dest == target); |
| 1368 | abnormal_edge_flags = e->flags & ~EDGE_FALLTHRU; |
| 1369 | e->flags &= EDGE_FALLTHRU; |
| 1370 | } |
| 1371 | else |
| 1372 | { |
| 1373 | gcc_assert (e->flags & EDGE_FALLTHRU); |
| 1374 | if (e->src == ENTRY_BLOCK_PTR) |
| 1375 | { |
| 1376 | /* We can't redirect the entry block. Create an empty block |
| 1377 | at the start of the function which we use to add the new |
| 1378 | jump. */ |
| 1379 | edge tmp; |
| 1380 | edge_iterator ei; |
| 1381 | bool found = false; |
| 1382 | |
| 1383 | basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR); |
| 1384 | |
| 1385 | /* Change the existing edge's source to be the new block, and add |
| 1386 | a new edge from the entry block to the new block. */ |
| 1387 | e->src = bb; |
| 1388 | for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); ) |
| 1389 | { |
| 1390 | if (tmp == e) |
| 1391 | { |
| 1392 | VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index); |
| 1393 | found = true; |
| 1394 | break; |
| 1395 | } |
| 1396 | else |
| 1397 | ei_next (&ei); |
| 1398 | } |
| 1399 | |
| 1400 | gcc_assert (found); |
| 1401 | |
| 1402 | VEC_safe_push (edge, gc, bb->succs, e); |
| 1403 | make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU); |
| 1404 | } |
| 1405 | } |
| 1406 | |
| 1407 | /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs |
| 1408 | don't point to the target or fallthru label. */ |
| 1409 | if (JUMP_P (BB_END (e->src)) |
| 1410 | && target != EXIT_BLOCK_PTR |
| 1411 | && (e->flags & EDGE_FALLTHRU) |
| 1412 | && (note = extract_asm_operands (PATTERN (BB_END (e->src))))) |
| 1413 | { |
| 1414 | int i, n = ASM_OPERANDS_LABEL_LENGTH (note); |
| 1415 | |
| 1416 | for (i = 0; i < n; ++i) |
| 1417 | { |
| 1418 | if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (e->dest)) |
| 1419 | XEXP (ASM_OPERANDS_LABEL (note, i), 0) = block_label (target); |
| 1420 | if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target)) |
| 1421 | asm_goto_edge = true; |
| 1422 | } |
| 1423 | } |
| 1424 | |
| 1425 | if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge) |
| 1426 | { |
| 1427 | gcov_type count = e->count; |
| 1428 | int probability = e->probability; |
| 1429 | /* Create the new structures. */ |
| 1430 | |
| 1431 | /* If the old block ended with a tablejump, skip its table |
| 1432 | by searching forward from there. Otherwise start searching |
| 1433 | forward from the last instruction of the old block. */ |
| 1434 | if (!tablejump_p (BB_END (e->src), NULL, ¬e)) |
| 1435 | note = BB_END (e->src); |
| 1436 | note = NEXT_INSN (note); |
| 1437 | |
| 1438 | jump_block = create_basic_block (note, NULL, e->src); |
| 1439 | jump_block->count = count; |
| 1440 | jump_block->frequency = EDGE_FREQUENCY (e); |
| 1441 | |
| 1442 | /* Make sure new block ends up in correct hot/cold section. */ |
| 1443 | |
| 1444 | BB_COPY_PARTITION (jump_block, e->src); |
| 1445 | if (flag_reorder_blocks_and_partition |
| 1446 | && targetm_common.have_named_sections |
| 1447 | && JUMP_P (BB_END (jump_block)) |
| 1448 | && !any_condjump_p (BB_END (jump_block)) |
| 1449 | && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING)) |
| 1450 | add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX); |
| 1451 | |
| 1452 | /* Wire edge in. */ |
| 1453 | new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU); |
| 1454 | new_edge->probability = probability; |
| 1455 | new_edge->count = count; |
| 1456 | |
| 1457 | /* Redirect old edge. */ |
| 1458 | redirect_edge_pred (e, jump_block); |
| 1459 | e->probability = REG_BR_PROB_BASE; |
| 1460 | |
| 1461 | /* If asm goto has any label refs to target's label, |
| 1462 | add also edge from asm goto bb to target. */ |
| 1463 | if (asm_goto_edge) |
| 1464 | { |
| 1465 | new_edge->probability /= 2; |
| 1466 | new_edge->count /= 2; |
| 1467 | jump_block->count /= 2; |
| 1468 | jump_block->frequency /= 2; |
| 1469 | new_edge = make_edge (new_edge->src, target, |
| 1470 | e->flags & ~EDGE_FALLTHRU); |
| 1471 | new_edge->probability = probability - probability / 2; |
| 1472 | new_edge->count = count - count / 2; |
| 1473 | } |
| 1474 | |
| 1475 | new_bb = jump_block; |
| 1476 | } |
| 1477 | else |
| 1478 | jump_block = e->src; |
| 1479 | |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 1480 | if (!IS_UNKNOWN_LOCATION (e->goto_locus)) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 1481 | loc = e->goto_locus; |
| 1482 | else |
| 1483 | loc = 0; |
| 1484 | e->flags &= ~EDGE_FALLTHRU; |
| 1485 | if (target == EXIT_BLOCK_PTR) |
| 1486 | { |
| 1487 | if (jump_label == ret_rtx) |
| 1488 | { |
| 1489 | #ifdef HAVE_return |
| 1490 | emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc); |
| 1491 | #else |
| 1492 | gcc_unreachable (); |
| 1493 | #endif |
| 1494 | } |
| 1495 | else |
| 1496 | { |
| 1497 | gcc_assert (jump_label == simple_return_rtx); |
| 1498 | #ifdef HAVE_simple_return |
| 1499 | emit_jump_insn_after_setloc (gen_simple_return (), |
| 1500 | BB_END (jump_block), loc); |
| 1501 | #else |
| 1502 | gcc_unreachable (); |
| 1503 | #endif |
| 1504 | } |
| 1505 | set_return_jump_label (BB_END (jump_block)); |
| 1506 | } |
| 1507 | else |
| 1508 | { |
| 1509 | rtx label = block_label (target); |
| 1510 | emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc); |
| 1511 | JUMP_LABEL (BB_END (jump_block)) = label; |
| 1512 | LABEL_NUSES (label)++; |
| 1513 | } |
| 1514 | |
| 1515 | emit_barrier_after (BB_END (jump_block)); |
| 1516 | redirect_edge_succ_nodup (e, target); |
| 1517 | |
| 1518 | if (abnormal_edge_flags) |
| 1519 | make_edge (src, target, abnormal_edge_flags); |
| 1520 | |
| 1521 | df_mark_solutions_dirty (); |
| 1522 | return new_bb; |
| 1523 | } |
| 1524 | |
| 1525 | /* Edge E is assumed to be fallthru edge. Emit needed jump instruction |
| 1526 | (and possibly create new basic block) to make edge non-fallthru. |
| 1527 | Return newly created BB or NULL if none. */ |
| 1528 | |
| 1529 | static basic_block |
| 1530 | rtl_force_nonfallthru (edge e) |
| 1531 | { |
| 1532 | return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX); |
| 1533 | } |
| 1534 | |
| 1535 | /* Redirect edge even at the expense of creating new jump insn or |
| 1536 | basic block. Return new basic block if created, NULL otherwise. |
| 1537 | Conversion must be possible. */ |
| 1538 | |
| 1539 | static basic_block |
| 1540 | rtl_redirect_edge_and_branch_force (edge e, basic_block target) |
| 1541 | { |
| 1542 | if (redirect_edge_and_branch (e, target) |
| 1543 | || e->dest == target) |
| 1544 | return NULL; |
| 1545 | |
| 1546 | /* In case the edge redirection failed, try to force it to be non-fallthru |
| 1547 | and redirect newly created simplejump. */ |
| 1548 | df_set_bb_dirty (e->src); |
| 1549 | return force_nonfallthru_and_redirect (e, target, NULL_RTX); |
| 1550 | } |
| 1551 | |
| 1552 | /* The given edge should potentially be a fallthru edge. If that is in |
| 1553 | fact true, delete the jump and barriers that are in the way. */ |
| 1554 | |
| 1555 | static void |
| 1556 | rtl_tidy_fallthru_edge (edge e) |
| 1557 | { |
| 1558 | rtx q; |
| 1559 | basic_block b = e->src, c = b->next_bb; |
| 1560 | |
| 1561 | /* ??? In a late-running flow pass, other folks may have deleted basic |
| 1562 | blocks by nopping out blocks, leaving multiple BARRIERs between here |
| 1563 | and the target label. They ought to be chastised and fixed. |
| 1564 | |
| 1565 | We can also wind up with a sequence of undeletable labels between |
| 1566 | one block and the next. |
| 1567 | |
| 1568 | So search through a sequence of barriers, labels, and notes for |
| 1569 | the head of block C and assert that we really do fall through. */ |
| 1570 | |
| 1571 | for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q)) |
| 1572 | if (INSN_P (q)) |
| 1573 | return; |
| 1574 | |
| 1575 | /* Remove what will soon cease being the jump insn from the source block. |
| 1576 | If block B consisted only of this single jump, turn it into a deleted |
| 1577 | note. */ |
| 1578 | q = BB_END (b); |
| 1579 | if (JUMP_P (q) |
| 1580 | && onlyjump_p (q) |
| 1581 | && (any_uncondjump_p (q) |
| 1582 | || single_succ_p (b))) |
| 1583 | { |
| 1584 | #ifdef HAVE_cc0 |
| 1585 | /* If this was a conditional jump, we need to also delete |
| 1586 | the insn that set cc0. */ |
| 1587 | if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q))) |
| 1588 | q = PREV_INSN (q); |
| 1589 | #endif |
| 1590 | |
| 1591 | q = PREV_INSN (q); |
| 1592 | } |
| 1593 | |
| 1594 | /* Selectively unlink the sequence. */ |
| 1595 | if (q != PREV_INSN (BB_HEAD (c))) |
| 1596 | delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false); |
| 1597 | |
| 1598 | e->flags |= EDGE_FALLTHRU; |
| 1599 | } |
| 1600 | |
| 1601 | /* Should move basic block BB after basic block AFTER. NIY. */ |
| 1602 | |
| 1603 | static bool |
| 1604 | rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED, |
| 1605 | basic_block after ATTRIBUTE_UNUSED) |
| 1606 | { |
| 1607 | return false; |
| 1608 | } |
| 1609 | |
| 1610 | /* Split a (typically critical) edge. Return the new block. |
| 1611 | The edge must not be abnormal. |
| 1612 | |
| 1613 | ??? The code generally expects to be called on critical edges. |
| 1614 | The case of a block ending in an unconditional jump to a |
| 1615 | block with multiple predecessors is not handled optimally. */ |
| 1616 | |
| 1617 | static basic_block |
| 1618 | rtl_split_edge (edge edge_in) |
| 1619 | { |
| 1620 | basic_block bb; |
| 1621 | rtx before; |
| 1622 | |
| 1623 | /* Abnormal edges cannot be split. */ |
| 1624 | gcc_assert (!(edge_in->flags & EDGE_ABNORMAL)); |
| 1625 | |
| 1626 | /* We are going to place the new block in front of edge destination. |
| 1627 | Avoid existence of fallthru predecessors. */ |
| 1628 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
| 1629 | { |
| 1630 | edge e = find_fallthru_edge (edge_in->dest->preds); |
| 1631 | |
| 1632 | if (e) |
| 1633 | force_nonfallthru (e); |
| 1634 | } |
| 1635 | |
| 1636 | /* Create the basic block note. */ |
| 1637 | if (edge_in->dest != EXIT_BLOCK_PTR) |
| 1638 | before = BB_HEAD (edge_in->dest); |
| 1639 | else |
| 1640 | before = NULL_RTX; |
| 1641 | |
| 1642 | /* If this is a fall through edge to the exit block, the blocks might be |
| 1643 | not adjacent, and the right place is after the source. */ |
| 1644 | if ((edge_in->flags & EDGE_FALLTHRU) && edge_in->dest == EXIT_BLOCK_PTR) |
| 1645 | { |
| 1646 | before = NEXT_INSN (BB_END (edge_in->src)); |
| 1647 | bb = create_basic_block (before, NULL, edge_in->src); |
| 1648 | BB_COPY_PARTITION (bb, edge_in->src); |
| 1649 | } |
| 1650 | else |
| 1651 | { |
| 1652 | bb = create_basic_block (before, NULL, edge_in->dest->prev_bb); |
| 1653 | /* ??? Why not edge_in->dest->prev_bb here? */ |
| 1654 | BB_COPY_PARTITION (bb, edge_in->dest); |
| 1655 | } |
| 1656 | |
| 1657 | make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU); |
| 1658 | |
| 1659 | /* For non-fallthru edges, we must adjust the predecessor's |
| 1660 | jump instruction to target our new block. */ |
| 1661 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
| 1662 | { |
| 1663 | edge redirected = redirect_edge_and_branch (edge_in, bb); |
| 1664 | gcc_assert (redirected); |
| 1665 | } |
| 1666 | else |
| 1667 | { |
| 1668 | if (edge_in->src != ENTRY_BLOCK_PTR) |
| 1669 | { |
| 1670 | /* For asm goto even splitting of fallthru edge might |
| 1671 | need insn patching, as other labels might point to the |
| 1672 | old label. */ |
| 1673 | rtx last = BB_END (edge_in->src); |
| 1674 | if (last |
| 1675 | && JUMP_P (last) |
| 1676 | && edge_in->dest != EXIT_BLOCK_PTR |
| 1677 | && extract_asm_operands (PATTERN (last)) != NULL_RTX |
| 1678 | && patch_jump_insn (last, before, bb)) |
| 1679 | df_set_bb_dirty (edge_in->src); |
| 1680 | } |
| 1681 | redirect_edge_succ (edge_in, bb); |
| 1682 | } |
| 1683 | |
| 1684 | return bb; |
| 1685 | } |
| 1686 | |
| 1687 | /* Queue instructions for insertion on an edge between two basic blocks. |
| 1688 | The new instructions and basic blocks (if any) will not appear in the |
| 1689 | CFG until commit_edge_insertions is called. */ |
| 1690 | |
| 1691 | void |
| 1692 | insert_insn_on_edge (rtx pattern, edge e) |
| 1693 | { |
| 1694 | /* We cannot insert instructions on an abnormal critical edge. |
| 1695 | It will be easier to find the culprit if we die now. */ |
| 1696 | gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e))); |
| 1697 | |
| 1698 | if (e->insns.r == NULL_RTX) |
| 1699 | start_sequence (); |
| 1700 | else |
| 1701 | push_to_sequence (e->insns.r); |
| 1702 | |
| 1703 | emit_insn (pattern); |
| 1704 | |
| 1705 | e->insns.r = get_insns (); |
| 1706 | end_sequence (); |
| 1707 | } |
| 1708 | |
| 1709 | /* Update the CFG for the instructions queued on edge E. */ |
| 1710 | |
| 1711 | void |
| 1712 | commit_one_edge_insertion (edge e) |
| 1713 | { |
| 1714 | rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last; |
| 1715 | basic_block bb; |
| 1716 | |
| 1717 | /* Pull the insns off the edge now since the edge might go away. */ |
| 1718 | insns = e->insns.r; |
| 1719 | e->insns.r = NULL_RTX; |
| 1720 | |
| 1721 | /* Figure out where to put these insns. If the destination has |
| 1722 | one predecessor, insert there. Except for the exit block. */ |
| 1723 | if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR) |
| 1724 | { |
| 1725 | bb = e->dest; |
| 1726 | |
| 1727 | /* Get the location correct wrt a code label, and "nice" wrt |
| 1728 | a basic block note, and before everything else. */ |
| 1729 | tmp = BB_HEAD (bb); |
| 1730 | if (LABEL_P (tmp)) |
| 1731 | tmp = NEXT_INSN (tmp); |
| 1732 | if (NOTE_INSN_BASIC_BLOCK_P (tmp)) |
| 1733 | tmp = NEXT_INSN (tmp); |
| 1734 | if (tmp == BB_HEAD (bb)) |
| 1735 | before = tmp; |
| 1736 | else if (tmp) |
| 1737 | after = PREV_INSN (tmp); |
| 1738 | else |
| 1739 | after = get_last_insn (); |
| 1740 | } |
| 1741 | |
| 1742 | /* If the source has one successor and the edge is not abnormal, |
| 1743 | insert there. Except for the entry block. */ |
| 1744 | else if ((e->flags & EDGE_ABNORMAL) == 0 |
| 1745 | && single_succ_p (e->src) |
| 1746 | && e->src != ENTRY_BLOCK_PTR) |
| 1747 | { |
| 1748 | bb = e->src; |
| 1749 | |
| 1750 | /* It is possible to have a non-simple jump here. Consider a target |
| 1751 | where some forms of unconditional jumps clobber a register. This |
| 1752 | happens on the fr30 for example. |
| 1753 | |
| 1754 | We know this block has a single successor, so we can just emit |
| 1755 | the queued insns before the jump. */ |
| 1756 | if (JUMP_P (BB_END (bb))) |
| 1757 | before = BB_END (bb); |
| 1758 | else |
| 1759 | { |
| 1760 | /* We'd better be fallthru, or we've lost track of what's what. */ |
| 1761 | gcc_assert (e->flags & EDGE_FALLTHRU); |
| 1762 | |
| 1763 | after = BB_END (bb); |
| 1764 | } |
| 1765 | } |
| 1766 | |
| 1767 | /* Otherwise we must split the edge. */ |
| 1768 | else |
| 1769 | { |
| 1770 | bb = split_edge (e); |
| 1771 | after = BB_END (bb); |
| 1772 | |
| 1773 | if (flag_reorder_blocks_and_partition |
| 1774 | && targetm_common.have_named_sections |
| 1775 | && e->src != ENTRY_BLOCK_PTR |
| 1776 | && BB_PARTITION (e->src) == BB_COLD_PARTITION |
| 1777 | && !(e->flags & EDGE_CROSSING) |
| 1778 | && JUMP_P (after) |
| 1779 | && !any_condjump_p (after) |
| 1780 | && (single_succ_edge (bb)->flags & EDGE_CROSSING)) |
| 1781 | add_reg_note (after, REG_CROSSING_JUMP, NULL_RTX); |
| 1782 | } |
| 1783 | |
| 1784 | /* Now that we've found the spot, do the insertion. */ |
| 1785 | if (before) |
| 1786 | { |
| 1787 | emit_insn_before_noloc (insns, before, bb); |
| 1788 | last = prev_nonnote_insn (before); |
| 1789 | } |
| 1790 | else |
| 1791 | last = emit_insn_after_noloc (insns, after, bb); |
| 1792 | |
| 1793 | if (returnjump_p (last)) |
| 1794 | { |
| 1795 | /* ??? Remove all outgoing edges from BB and add one for EXIT. |
| 1796 | This is not currently a problem because this only happens |
| 1797 | for the (single) epilogue, which already has a fallthru edge |
| 1798 | to EXIT. */ |
| 1799 | |
| 1800 | e = single_succ_edge (bb); |
| 1801 | gcc_assert (e->dest == EXIT_BLOCK_PTR |
| 1802 | && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU)); |
| 1803 | |
| 1804 | e->flags &= ~EDGE_FALLTHRU; |
| 1805 | emit_barrier_after (last); |
| 1806 | |
| 1807 | if (before) |
| 1808 | delete_insn (before); |
| 1809 | } |
| 1810 | else |
| 1811 | gcc_assert (!JUMP_P (last)); |
| 1812 | } |
| 1813 | |
| 1814 | /* Update the CFG for all queued instructions. */ |
| 1815 | |
| 1816 | void |
| 1817 | commit_edge_insertions (void) |
| 1818 | { |
| 1819 | basic_block bb; |
| 1820 | |
| 1821 | #ifdef ENABLE_CHECKING |
| 1822 | verify_flow_info (); |
| 1823 | #endif |
| 1824 | |
| 1825 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) |
| 1826 | { |
| 1827 | edge e; |
| 1828 | edge_iterator ei; |
| 1829 | |
| 1830 | FOR_EACH_EDGE (e, ei, bb->succs) |
| 1831 | if (e->insns.r) |
| 1832 | commit_one_edge_insertion (e); |
| 1833 | } |
| 1834 | } |
| 1835 | |
| 1836 | |
| 1837 | /* Print out RTL-specific basic block information (live information |
| 1838 | at start and end with TDF_DETAILS). FLAGS are the TDF_* masks |
| 1839 | documented in dumpfile.h. */ |
| 1840 | |
| 1841 | static void |
| 1842 | rtl_dump_bb (FILE *outf, basic_block bb, int indent, int flags) |
| 1843 | { |
| 1844 | rtx insn; |
| 1845 | rtx last; |
| 1846 | char *s_indent; |
| 1847 | |
| 1848 | s_indent = (char *) alloca ((size_t) indent + 1); |
| 1849 | memset (s_indent, ' ', (size_t) indent); |
| 1850 | s_indent[indent] = '\0'; |
| 1851 | |
| 1852 | if (df && (flags & TDF_DETAILS)) |
| 1853 | { |
| 1854 | df_dump_top (bb, outf); |
| 1855 | putc ('\n', outf); |
| 1856 | } |
| 1857 | |
| 1858 | if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK) |
| 1859 | for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last; |
| 1860 | insn = NEXT_INSN (insn)) |
| 1861 | { |
| 1862 | if (! (flags & TDF_SLIM)) |
| 1863 | print_rtl_single (outf, insn); |
| 1864 | else |
| 1865 | dump_insn_slim (outf, insn); |
| 1866 | |
| 1867 | } |
| 1868 | |
| 1869 | if (df && (flags & TDF_DETAILS)) |
| 1870 | { |
| 1871 | df_dump_bottom (bb, outf); |
| 1872 | putc ('\n', outf); |
| 1873 | } |
| 1874 | |
| 1875 | } |
| 1876 | |
| 1877 | /* Like dump_function_to_file, but for RTL. Print out dataflow information |
| 1878 | for the start of each basic block. FLAGS are the TDF_* masks documented |
| 1879 | in dumpfile.h. */ |
| 1880 | |
| 1881 | void |
| 1882 | print_rtl_with_bb (FILE *outf, const_rtx rtx_first, int flags) |
| 1883 | { |
| 1884 | const_rtx tmp_rtx; |
| 1885 | if (rtx_first == 0) |
| 1886 | fprintf (outf, "(nil)\n"); |
| 1887 | else |
| 1888 | { |
| 1889 | enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; |
| 1890 | int max_uid = get_max_uid (); |
| 1891 | basic_block *start = XCNEWVEC (basic_block, max_uid); |
| 1892 | basic_block *end = XCNEWVEC (basic_block, max_uid); |
| 1893 | enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid); |
| 1894 | basic_block bb; |
| 1895 | |
| 1896 | /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most |
| 1897 | insns, but the CFG is not maintained so the basic block info |
| 1898 | is not reliable. Therefore it's omitted from the dumps. */ |
| 1899 | if (! (cfun->curr_properties & PROP_cfg)) |
| 1900 | flags &= ~TDF_BLOCKS; |
| 1901 | |
| 1902 | if (df) |
| 1903 | df_dump_start (outf); |
| 1904 | |
| 1905 | if (flags & TDF_BLOCKS) |
| 1906 | { |
| 1907 | FOR_EACH_BB_REVERSE (bb) |
| 1908 | { |
| 1909 | rtx x; |
| 1910 | |
| 1911 | start[INSN_UID (BB_HEAD (bb))] = bb; |
| 1912 | end[INSN_UID (BB_END (bb))] = bb; |
| 1913 | for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x)) |
| 1914 | { |
| 1915 | enum bb_state state = IN_MULTIPLE_BB; |
| 1916 | |
| 1917 | if (in_bb_p[INSN_UID (x)] == NOT_IN_BB) |
| 1918 | state = IN_ONE_BB; |
| 1919 | in_bb_p[INSN_UID (x)] = state; |
| 1920 | |
| 1921 | if (x == BB_END (bb)) |
| 1922 | break; |
| 1923 | } |
| 1924 | } |
| 1925 | } |
| 1926 | |
| 1927 | for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) |
| 1928 | { |
| 1929 | if (flags & TDF_BLOCKS) |
| 1930 | { |
| 1931 | bb = start[INSN_UID (tmp_rtx)]; |
| 1932 | if (bb != NULL) |
| 1933 | { |
| 1934 | dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, true, false); |
| 1935 | if (df && (flags & TDF_DETAILS)) |
| 1936 | df_dump_top (bb, outf); |
| 1937 | } |
| 1938 | |
| 1939 | if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB |
| 1940 | && !NOTE_P (tmp_rtx) |
| 1941 | && !BARRIER_P (tmp_rtx)) |
| 1942 | fprintf (outf, ";; Insn is not within a basic block\n"); |
| 1943 | else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB) |
| 1944 | fprintf (outf, ";; Insn is in multiple basic blocks\n"); |
| 1945 | } |
| 1946 | |
| 1947 | if (! (flags & TDF_SLIM)) |
| 1948 | print_rtl_single (outf, tmp_rtx); |
| 1949 | else |
| 1950 | dump_insn_slim (outf, tmp_rtx); |
| 1951 | |
| 1952 | if (flags & TDF_BLOCKS) |
| 1953 | { |
| 1954 | bb = end[INSN_UID (tmp_rtx)]; |
| 1955 | if (bb != NULL) |
| 1956 | { |
| 1957 | dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, false, true); |
| 1958 | if (df && (flags & TDF_DETAILS)) |
| 1959 | df_dump_bottom (bb, outf); |
| 1960 | putc ('\n', outf); |
| 1961 | } |
| 1962 | } |
| 1963 | } |
| 1964 | |
| 1965 | free (start); |
| 1966 | free (end); |
| 1967 | free (in_bb_p); |
| 1968 | } |
| 1969 | |
| 1970 | if (crtl->epilogue_delay_list != 0) |
| 1971 | { |
| 1972 | fprintf (outf, "\n;; Insns in epilogue delay list:\n\n"); |
| 1973 | for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0; |
| 1974 | tmp_rtx = XEXP (tmp_rtx, 1)) |
| 1975 | print_rtl_single (outf, XEXP (tmp_rtx, 0)); |
| 1976 | } |
| 1977 | } |
| 1978 | |
| 1979 | /* Update the branch probability of BB if a REG_BR_PROB is present. */ |
| 1980 | |
| 1981 | void |
| 1982 | update_br_prob_note (basic_block bb) |
| 1983 | { |
| 1984 | rtx note; |
| 1985 | if (!JUMP_P (BB_END (bb))) |
| 1986 | return; |
| 1987 | note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX); |
| 1988 | if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability) |
| 1989 | return; |
| 1990 | XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability); |
| 1991 | } |
| 1992 | |
| 1993 | /* Get the last insn associated with block BB (that includes barriers and |
| 1994 | tablejumps after BB). */ |
| 1995 | rtx |
| 1996 | get_last_bb_insn (basic_block bb) |
| 1997 | { |
| 1998 | rtx tmp; |
| 1999 | rtx end = BB_END (bb); |
| 2000 | |
| 2001 | /* Include any jump table following the basic block. */ |
| 2002 | if (tablejump_p (end, NULL, &tmp)) |
| 2003 | end = tmp; |
| 2004 | |
| 2005 | /* Include any barriers that may follow the basic block. */ |
| 2006 | tmp = next_nonnote_insn_bb (end); |
| 2007 | while (tmp && BARRIER_P (tmp)) |
| 2008 | { |
| 2009 | end = tmp; |
| 2010 | tmp = next_nonnote_insn_bb (end); |
| 2011 | } |
| 2012 | |
| 2013 | return end; |
| 2014 | } |
| 2015 | |
| 2016 | /* Verify the CFG and RTL consistency common for both underlying RTL and |
| 2017 | cfglayout RTL. |
| 2018 | |
| 2019 | Currently it does following checks: |
| 2020 | |
| 2021 | - overlapping of basic blocks |
| 2022 | - insns with wrong BLOCK_FOR_INSN pointers |
| 2023 | - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note) |
| 2024 | - tails of basic blocks (ensure that boundary is necessary) |
| 2025 | - scans body of the basic block for JUMP_INSN, CODE_LABEL |
| 2026 | and NOTE_INSN_BASIC_BLOCK |
| 2027 | - verify that no fall_thru edge crosses hot/cold partition boundaries |
| 2028 | - verify that there are no pending RTL branch predictions |
| 2029 | |
| 2030 | In future it can be extended check a lot of other stuff as well |
| 2031 | (reachability of basic blocks, life information, etc. etc.). */ |
| 2032 | |
| 2033 | static int |
| 2034 | rtl_verify_flow_info_1 (void) |
| 2035 | { |
| 2036 | rtx x; |
| 2037 | int err = 0; |
| 2038 | basic_block bb; |
| 2039 | |
| 2040 | /* Check the general integrity of the basic blocks. */ |
| 2041 | FOR_EACH_BB_REVERSE (bb) |
| 2042 | { |
| 2043 | rtx insn; |
| 2044 | |
| 2045 | if (!(bb->flags & BB_RTL)) |
| 2046 | { |
| 2047 | error ("BB_RTL flag not set for block %d", bb->index); |
| 2048 | err = 1; |
| 2049 | } |
| 2050 | |
| 2051 | FOR_BB_INSNS (bb, insn) |
| 2052 | if (BLOCK_FOR_INSN (insn) != bb) |
| 2053 | { |
| 2054 | error ("insn %d basic block pointer is %d, should be %d", |
| 2055 | INSN_UID (insn), |
| 2056 | BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0, |
| 2057 | bb->index); |
| 2058 | err = 1; |
| 2059 | } |
| 2060 | |
| 2061 | for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn)) |
| 2062 | if (!BARRIER_P (insn) |
| 2063 | && BLOCK_FOR_INSN (insn) != NULL) |
| 2064 | { |
| 2065 | error ("insn %d in header of bb %d has non-NULL basic block", |
| 2066 | INSN_UID (insn), bb->index); |
| 2067 | err = 1; |
| 2068 | } |
| 2069 | for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn)) |
| 2070 | if (!BARRIER_P (insn) |
| 2071 | && BLOCK_FOR_INSN (insn) != NULL) |
| 2072 | { |
| 2073 | error ("insn %d in footer of bb %d has non-NULL basic block", |
| 2074 | INSN_UID (insn), bb->index); |
| 2075 | err = 1; |
| 2076 | } |
| 2077 | } |
| 2078 | |
| 2079 | /* Now check the basic blocks (boundaries etc.) */ |
| 2080 | FOR_EACH_BB_REVERSE (bb) |
| 2081 | { |
| 2082 | int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0; |
| 2083 | edge e, fallthru = NULL; |
| 2084 | rtx note; |
| 2085 | edge_iterator ei; |
| 2086 | |
| 2087 | if (JUMP_P (BB_END (bb)) |
| 2088 | && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX)) |
| 2089 | && EDGE_COUNT (bb->succs) >= 2 |
| 2090 | && any_condjump_p (BB_END (bb))) |
| 2091 | { |
| 2092 | if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability |
| 2093 | && profile_status != PROFILE_ABSENT) |
| 2094 | { |
| 2095 | error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i", |
| 2096 | INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability); |
| 2097 | err = 1; |
| 2098 | } |
| 2099 | } |
| 2100 | FOR_EACH_EDGE (e, ei, bb->succs) |
| 2101 | { |
| 2102 | bool is_crossing; |
| 2103 | |
| 2104 | if (e->flags & EDGE_FALLTHRU) |
| 2105 | n_fallthru++, fallthru = e; |
| 2106 | |
| 2107 | is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest) |
| 2108 | && e->src != ENTRY_BLOCK_PTR |
| 2109 | && e->dest != EXIT_BLOCK_PTR); |
| 2110 | if (e->flags & EDGE_CROSSING) |
| 2111 | { |
| 2112 | if (!is_crossing) |
| 2113 | { |
| 2114 | error ("EDGE_CROSSING incorrectly set across same section"); |
| 2115 | err = 1; |
| 2116 | } |
| 2117 | if (e->flags & EDGE_FALLTHRU) |
| 2118 | { |
| 2119 | error ("fallthru edge crosses section boundary (bb %i)", |
| 2120 | e->src->index); |
| 2121 | err = 1; |
| 2122 | } |
| 2123 | if (e->flags & EDGE_EH) |
| 2124 | { |
| 2125 | error ("EH edge crosses section boundary (bb %i)", |
| 2126 | e->src->index); |
| 2127 | err = 1; |
| 2128 | } |
| 2129 | } |
| 2130 | else if (is_crossing) |
| 2131 | { |
| 2132 | error ("EDGE_CROSSING missing across section boundary"); |
| 2133 | err = 1; |
| 2134 | } |
| 2135 | |
| 2136 | if ((e->flags & ~(EDGE_DFS_BACK |
| 2137 | | EDGE_CAN_FALLTHRU |
| 2138 | | EDGE_IRREDUCIBLE_LOOP |
| 2139 | | EDGE_LOOP_EXIT |
| 2140 | | EDGE_CROSSING |
| 2141 | | EDGE_PRESERVE)) == 0) |
| 2142 | n_branch++; |
| 2143 | |
| 2144 | if (e->flags & EDGE_ABNORMAL_CALL) |
| 2145 | n_call++; |
| 2146 | |
| 2147 | if (e->flags & EDGE_EH) |
| 2148 | n_eh++; |
| 2149 | else if (e->flags & EDGE_ABNORMAL) |
| 2150 | n_abnormal++; |
| 2151 | } |
| 2152 | |
| 2153 | if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX)) |
| 2154 | { |
| 2155 | error ("missing REG_EH_REGION note in the end of bb %i", bb->index); |
| 2156 | err = 1; |
| 2157 | } |
| 2158 | if (n_eh > 1) |
| 2159 | { |
| 2160 | error ("too many eh edges %i", bb->index); |
| 2161 | err = 1; |
| 2162 | } |
| 2163 | if (n_branch |
| 2164 | && (!JUMP_P (BB_END (bb)) |
| 2165 | || (n_branch > 1 && (any_uncondjump_p (BB_END (bb)) |
| 2166 | || any_condjump_p (BB_END (bb)))))) |
| 2167 | { |
| 2168 | error ("too many outgoing branch edges from bb %i", bb->index); |
| 2169 | err = 1; |
| 2170 | } |
| 2171 | if (n_fallthru && any_uncondjump_p (BB_END (bb))) |
| 2172 | { |
| 2173 | error ("fallthru edge after unconditional jump %i", bb->index); |
| 2174 | err = 1; |
| 2175 | } |
| 2176 | if (n_branch != 1 && any_uncondjump_p (BB_END (bb))) |
| 2177 | { |
| 2178 | error ("wrong number of branch edges after unconditional jump %i", |
| 2179 | bb->index); |
| 2180 | err = 1; |
| 2181 | } |
| 2182 | if (n_branch != 1 && any_condjump_p (BB_END (bb)) |
| 2183 | && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest)) |
| 2184 | { |
| 2185 | error ("wrong amount of branch edges after conditional jump %i", |
| 2186 | bb->index); |
| 2187 | err = 1; |
| 2188 | } |
| 2189 | if (n_call && !CALL_P (BB_END (bb))) |
| 2190 | { |
| 2191 | error ("call edges for non-call insn in bb %i", bb->index); |
| 2192 | err = 1; |
| 2193 | } |
| 2194 | if (n_abnormal |
| 2195 | && (!CALL_P (BB_END (bb)) && n_call != n_abnormal) |
| 2196 | && (!JUMP_P (BB_END (bb)) |
| 2197 | || any_condjump_p (BB_END (bb)) |
| 2198 | || any_uncondjump_p (BB_END (bb)))) |
| 2199 | { |
| 2200 | error ("abnormal edges for no purpose in bb %i", bb->index); |
| 2201 | err = 1; |
| 2202 | } |
| 2203 | |
| 2204 | for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x)) |
| 2205 | /* We may have a barrier inside a basic block before dead code |
| 2206 | elimination. There is no BLOCK_FOR_INSN field in a barrier. */ |
| 2207 | if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb) |
| 2208 | { |
| 2209 | debug_rtx (x); |
| 2210 | if (! BLOCK_FOR_INSN (x)) |
| 2211 | error |
| 2212 | ("insn %d inside basic block %d but block_for_insn is NULL", |
| 2213 | INSN_UID (x), bb->index); |
| 2214 | else |
| 2215 | error |
| 2216 | ("insn %d inside basic block %d but block_for_insn is %i", |
| 2217 | INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index); |
| 2218 | |
| 2219 | err = 1; |
| 2220 | } |
| 2221 | |
| 2222 | /* OK pointers are correct. Now check the header of basic |
| 2223 | block. It ought to contain optional CODE_LABEL followed |
| 2224 | by NOTE_BASIC_BLOCK. */ |
| 2225 | x = BB_HEAD (bb); |
| 2226 | if (LABEL_P (x)) |
| 2227 | { |
| 2228 | if (BB_END (bb) == x) |
| 2229 | { |
| 2230 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d", |
| 2231 | bb->index); |
| 2232 | err = 1; |
| 2233 | } |
| 2234 | |
| 2235 | x = NEXT_INSN (x); |
| 2236 | } |
| 2237 | |
| 2238 | if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb) |
| 2239 | { |
| 2240 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d", |
| 2241 | bb->index); |
| 2242 | err = 1; |
| 2243 | } |
| 2244 | |
| 2245 | if (BB_END (bb) == x) |
| 2246 | /* Do checks for empty blocks here. */ |
| 2247 | ; |
| 2248 | else |
| 2249 | for (x = NEXT_INSN (x); x; x = NEXT_INSN (x)) |
| 2250 | { |
| 2251 | if (NOTE_INSN_BASIC_BLOCK_P (x)) |
| 2252 | { |
| 2253 | error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d", |
| 2254 | INSN_UID (x), bb->index); |
| 2255 | err = 1; |
| 2256 | } |
| 2257 | |
| 2258 | if (x == BB_END (bb)) |
| 2259 | break; |
| 2260 | |
| 2261 | if (control_flow_insn_p (x)) |
| 2262 | { |
| 2263 | error ("in basic block %d:", bb->index); |
| 2264 | fatal_insn ("flow control insn inside a basic block", x); |
| 2265 | } |
| 2266 | } |
| 2267 | } |
| 2268 | |
| 2269 | /* Clean up. */ |
| 2270 | return err; |
| 2271 | } |
| 2272 | |
| 2273 | /* Verify the CFG and RTL consistency common for both underlying RTL and |
| 2274 | cfglayout RTL. |
| 2275 | |
| 2276 | Currently it does following checks: |
| 2277 | - all checks of rtl_verify_flow_info_1 |
| 2278 | - test head/end pointers |
| 2279 | - check that all insns are in the basic blocks |
| 2280 | (except the switch handling code, barriers and notes) |
| 2281 | - check that all returns are followed by barriers |
| 2282 | - check that all fallthru edge points to the adjacent blocks. */ |
| 2283 | |
| 2284 | static int |
| 2285 | rtl_verify_flow_info (void) |
| 2286 | { |
| 2287 | basic_block bb; |
| 2288 | int err = rtl_verify_flow_info_1 (); |
| 2289 | rtx x; |
| 2290 | rtx last_head = get_last_insn (); |
| 2291 | basic_block *bb_info; |
| 2292 | int num_bb_notes; |
| 2293 | const rtx rtx_first = get_insns (); |
| 2294 | basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL; |
| 2295 | const int max_uid = get_max_uid (); |
| 2296 | |
| 2297 | bb_info = XCNEWVEC (basic_block, max_uid); |
| 2298 | |
| 2299 | FOR_EACH_BB_REVERSE (bb) |
| 2300 | { |
| 2301 | edge e; |
| 2302 | rtx head = BB_HEAD (bb); |
| 2303 | rtx end = BB_END (bb); |
| 2304 | |
| 2305 | for (x = last_head; x != NULL_RTX; x = PREV_INSN (x)) |
| 2306 | { |
| 2307 | /* Verify the end of the basic block is in the INSN chain. */ |
| 2308 | if (x == end) |
| 2309 | break; |
| 2310 | |
| 2311 | /* And that the code outside of basic blocks has NULL bb field. */ |
| 2312 | if (!BARRIER_P (x) |
| 2313 | && BLOCK_FOR_INSN (x) != NULL) |
| 2314 | { |
| 2315 | error ("insn %d outside of basic blocks has non-NULL bb field", |
| 2316 | INSN_UID (x)); |
| 2317 | err = 1; |
| 2318 | } |
| 2319 | } |
| 2320 | |
| 2321 | if (!x) |
| 2322 | { |
| 2323 | error ("end insn %d for block %d not found in the insn stream", |
| 2324 | INSN_UID (end), bb->index); |
| 2325 | err = 1; |
| 2326 | } |
| 2327 | |
| 2328 | /* Work backwards from the end to the head of the basic block |
| 2329 | to verify the head is in the RTL chain. */ |
| 2330 | for (; x != NULL_RTX; x = PREV_INSN (x)) |
| 2331 | { |
| 2332 | /* While walking over the insn chain, verify insns appear |
| 2333 | in only one basic block. */ |
| 2334 | if (bb_info[INSN_UID (x)] != NULL) |
| 2335 | { |
| 2336 | error ("insn %d is in multiple basic blocks (%d and %d)", |
| 2337 | INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index); |
| 2338 | err = 1; |
| 2339 | } |
| 2340 | |
| 2341 | bb_info[INSN_UID (x)] = bb; |
| 2342 | |
| 2343 | if (x == head) |
| 2344 | break; |
| 2345 | } |
| 2346 | if (!x) |
| 2347 | { |
| 2348 | error ("head insn %d for block %d not found in the insn stream", |
| 2349 | INSN_UID (head), bb->index); |
| 2350 | err = 1; |
| 2351 | } |
| 2352 | |
| 2353 | last_head = PREV_INSN (x); |
| 2354 | |
| 2355 | e = find_fallthru_edge (bb->succs); |
| 2356 | if (!e) |
| 2357 | { |
| 2358 | rtx insn; |
| 2359 | |
| 2360 | /* Ensure existence of barrier in BB with no fallthru edges. */ |
| 2361 | for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn)) |
| 2362 | { |
| 2363 | if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn)) |
| 2364 | { |
| 2365 | error ("missing barrier after block %i", bb->index); |
| 2366 | err = 1; |
| 2367 | break; |
| 2368 | } |
| 2369 | if (BARRIER_P (insn)) |
| 2370 | break; |
| 2371 | } |
| 2372 | } |
| 2373 | else if (e->src != ENTRY_BLOCK_PTR |
| 2374 | && e->dest != EXIT_BLOCK_PTR) |
| 2375 | { |
| 2376 | rtx insn; |
| 2377 | |
| 2378 | if (e->src->next_bb != e->dest) |
| 2379 | { |
| 2380 | error |
| 2381 | ("verify_flow_info: Incorrect blocks for fallthru %i->%i", |
| 2382 | e->src->index, e->dest->index); |
| 2383 | err = 1; |
| 2384 | } |
| 2385 | else |
| 2386 | for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest); |
| 2387 | insn = NEXT_INSN (insn)) |
| 2388 | if (BARRIER_P (insn) || INSN_P (insn)) |
| 2389 | { |
| 2390 | error ("verify_flow_info: Incorrect fallthru %i->%i", |
| 2391 | e->src->index, e->dest->index); |
| 2392 | fatal_insn ("wrong insn in the fallthru edge", insn); |
| 2393 | err = 1; |
| 2394 | } |
| 2395 | } |
| 2396 | } |
| 2397 | |
| 2398 | for (x = last_head; x != NULL_RTX; x = PREV_INSN (x)) |
| 2399 | { |
| 2400 | /* Check that the code before the first basic block has NULL |
| 2401 | bb field. */ |
| 2402 | if (!BARRIER_P (x) |
| 2403 | && BLOCK_FOR_INSN (x) != NULL) |
| 2404 | { |
| 2405 | error ("insn %d outside of basic blocks has non-NULL bb field", |
| 2406 | INSN_UID (x)); |
| 2407 | err = 1; |
| 2408 | } |
| 2409 | } |
| 2410 | free (bb_info); |
| 2411 | |
| 2412 | num_bb_notes = 0; |
| 2413 | last_bb_seen = ENTRY_BLOCK_PTR; |
| 2414 | |
| 2415 | for (x = rtx_first; x; x = NEXT_INSN (x)) |
| 2416 | { |
| 2417 | if (NOTE_INSN_BASIC_BLOCK_P (x)) |
| 2418 | { |
| 2419 | bb = NOTE_BASIC_BLOCK (x); |
| 2420 | |
| 2421 | num_bb_notes++; |
| 2422 | if (bb != last_bb_seen->next_bb) |
| 2423 | internal_error ("basic blocks not laid down consecutively"); |
| 2424 | |
| 2425 | curr_bb = last_bb_seen = bb; |
| 2426 | } |
| 2427 | |
| 2428 | if (!curr_bb) |
| 2429 | { |
| 2430 | switch (GET_CODE (x)) |
| 2431 | { |
| 2432 | case BARRIER: |
| 2433 | case NOTE: |
| 2434 | break; |
| 2435 | |
| 2436 | case CODE_LABEL: |
| 2437 | /* An addr_vec is placed outside any basic block. */ |
| 2438 | if (NEXT_INSN (x) |
| 2439 | && JUMP_TABLE_DATA_P (NEXT_INSN (x))) |
| 2440 | x = NEXT_INSN (x); |
| 2441 | |
| 2442 | /* But in any case, non-deletable labels can appear anywhere. */ |
| 2443 | break; |
| 2444 | |
| 2445 | default: |
| 2446 | fatal_insn ("insn outside basic block", x); |
| 2447 | } |
| 2448 | } |
| 2449 | |
| 2450 | if (JUMP_P (x) |
| 2451 | && returnjump_p (x) && ! condjump_p (x) |
| 2452 | && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x)))) |
| 2453 | fatal_insn ("return not followed by barrier", x); |
| 2454 | if (curr_bb && x == BB_END (curr_bb)) |
| 2455 | curr_bb = NULL; |
| 2456 | } |
| 2457 | |
| 2458 | if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS) |
| 2459 | internal_error |
| 2460 | ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)", |
| 2461 | num_bb_notes, n_basic_blocks); |
| 2462 | |
| 2463 | return err; |
| 2464 | } |
| 2465 | |
| 2466 | /* Assume that the preceding pass has possibly eliminated jump instructions |
| 2467 | or converted the unconditional jumps. Eliminate the edges from CFG. |
| 2468 | Return true if any edges are eliminated. */ |
| 2469 | |
| 2470 | bool |
| 2471 | purge_dead_edges (basic_block bb) |
| 2472 | { |
| 2473 | edge e; |
| 2474 | rtx insn = BB_END (bb), note; |
| 2475 | bool purged = false; |
| 2476 | bool found; |
| 2477 | edge_iterator ei; |
| 2478 | |
| 2479 | if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb)) |
| 2480 | do |
| 2481 | insn = PREV_INSN (insn); |
| 2482 | while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb)); |
| 2483 | |
| 2484 | /* If this instruction cannot trap, remove REG_EH_REGION notes. */ |
| 2485 | if (NONJUMP_INSN_P (insn) |
| 2486 | && (note = find_reg_note (insn, REG_EH_REGION, NULL))) |
| 2487 | { |
| 2488 | rtx eqnote; |
| 2489 | |
| 2490 | if (! may_trap_p (PATTERN (insn)) |
| 2491 | || ((eqnote = find_reg_equal_equiv_note (insn)) |
| 2492 | && ! may_trap_p (XEXP (eqnote, 0)))) |
| 2493 | remove_note (insn, note); |
| 2494 | } |
| 2495 | |
| 2496 | /* Cleanup abnormal edges caused by exceptions or non-local gotos. */ |
| 2497 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
| 2498 | { |
| 2499 | bool remove = false; |
| 2500 | |
| 2501 | /* There are three types of edges we need to handle correctly here: EH |
| 2502 | edges, abnormal call EH edges, and abnormal call non-EH edges. The |
| 2503 | latter can appear when nonlocal gotos are used. */ |
| 2504 | if (e->flags & EDGE_ABNORMAL_CALL) |
| 2505 | { |
| 2506 | if (!CALL_P (insn)) |
| 2507 | remove = true; |
| 2508 | else if (can_nonlocal_goto (insn)) |
| 2509 | ; |
| 2510 | else if ((e->flags & EDGE_EH) && can_throw_internal (insn)) |
| 2511 | ; |
| 2512 | else if (flag_tm && find_reg_note (insn, REG_TM, NULL)) |
| 2513 | ; |
| 2514 | else |
| 2515 | remove = true; |
| 2516 | } |
| 2517 | else if (e->flags & EDGE_EH) |
| 2518 | remove = !can_throw_internal (insn); |
| 2519 | |
| 2520 | if (remove) |
| 2521 | { |
| 2522 | remove_edge (e); |
| 2523 | df_set_bb_dirty (bb); |
| 2524 | purged = true; |
| 2525 | } |
| 2526 | else |
| 2527 | ei_next (&ei); |
| 2528 | } |
| 2529 | |
| 2530 | if (JUMP_P (insn)) |
| 2531 | { |
| 2532 | rtx note; |
| 2533 | edge b,f; |
| 2534 | edge_iterator ei; |
| 2535 | |
| 2536 | /* We do care only about conditional jumps and simplejumps. */ |
| 2537 | if (!any_condjump_p (insn) |
| 2538 | && !returnjump_p (insn) |
| 2539 | && !simplejump_p (insn)) |
| 2540 | return purged; |
| 2541 | |
| 2542 | /* Branch probability/prediction notes are defined only for |
| 2543 | condjumps. We've possibly turned condjump into simplejump. */ |
| 2544 | if (simplejump_p (insn)) |
| 2545 | { |
| 2546 | note = find_reg_note (insn, REG_BR_PROB, NULL); |
| 2547 | if (note) |
| 2548 | remove_note (insn, note); |
| 2549 | while ((note = find_reg_note (insn, REG_BR_PRED, NULL))) |
| 2550 | remove_note (insn, note); |
| 2551 | } |
| 2552 | |
| 2553 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
| 2554 | { |
| 2555 | /* Avoid abnormal flags to leak from computed jumps turned |
| 2556 | into simplejumps. */ |
| 2557 | |
| 2558 | e->flags &= ~EDGE_ABNORMAL; |
| 2559 | |
| 2560 | /* See if this edge is one we should keep. */ |
| 2561 | if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn)) |
| 2562 | /* A conditional jump can fall through into the next |
| 2563 | block, so we should keep the edge. */ |
| 2564 | { |
| 2565 | ei_next (&ei); |
| 2566 | continue; |
| 2567 | } |
| 2568 | else if (e->dest != EXIT_BLOCK_PTR |
| 2569 | && BB_HEAD (e->dest) == JUMP_LABEL (insn)) |
| 2570 | /* If the destination block is the target of the jump, |
| 2571 | keep the edge. */ |
| 2572 | { |
| 2573 | ei_next (&ei); |
| 2574 | continue; |
| 2575 | } |
| 2576 | else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn)) |
| 2577 | /* If the destination block is the exit block, and this |
| 2578 | instruction is a return, then keep the edge. */ |
| 2579 | { |
| 2580 | ei_next (&ei); |
| 2581 | continue; |
| 2582 | } |
| 2583 | else if ((e->flags & EDGE_EH) && can_throw_internal (insn)) |
| 2584 | /* Keep the edges that correspond to exceptions thrown by |
| 2585 | this instruction and rematerialize the EDGE_ABNORMAL |
| 2586 | flag we just cleared above. */ |
| 2587 | { |
| 2588 | e->flags |= EDGE_ABNORMAL; |
| 2589 | ei_next (&ei); |
| 2590 | continue; |
| 2591 | } |
| 2592 | |
| 2593 | /* We do not need this edge. */ |
| 2594 | df_set_bb_dirty (bb); |
| 2595 | purged = true; |
| 2596 | remove_edge (e); |
| 2597 | } |
| 2598 | |
| 2599 | if (EDGE_COUNT (bb->succs) == 0 || !purged) |
| 2600 | return purged; |
| 2601 | |
| 2602 | if (dump_file) |
| 2603 | fprintf (dump_file, "Purged edges from bb %i\n", bb->index); |
| 2604 | |
| 2605 | if (!optimize) |
| 2606 | return purged; |
| 2607 | |
| 2608 | /* Redistribute probabilities. */ |
| 2609 | if (single_succ_p (bb)) |
| 2610 | { |
| 2611 | single_succ_edge (bb)->probability = REG_BR_PROB_BASE; |
| 2612 | single_succ_edge (bb)->count = bb->count; |
| 2613 | } |
| 2614 | else |
| 2615 | { |
| 2616 | note = find_reg_note (insn, REG_BR_PROB, NULL); |
| 2617 | if (!note) |
| 2618 | return purged; |
| 2619 | |
| 2620 | b = BRANCH_EDGE (bb); |
| 2621 | f = FALLTHRU_EDGE (bb); |
| 2622 | b->probability = INTVAL (XEXP (note, 0)); |
| 2623 | f->probability = REG_BR_PROB_BASE - b->probability; |
| 2624 | b->count = bb->count * b->probability / REG_BR_PROB_BASE; |
| 2625 | f->count = bb->count * f->probability / REG_BR_PROB_BASE; |
| 2626 | } |
| 2627 | |
| 2628 | return purged; |
| 2629 | } |
| 2630 | else if (CALL_P (insn) && SIBLING_CALL_P (insn)) |
| 2631 | { |
| 2632 | /* First, there should not be any EH or ABCALL edges resulting |
| 2633 | from non-local gotos and the like. If there were, we shouldn't |
| 2634 | have created the sibcall in the first place. Second, there |
| 2635 | should of course never have been a fallthru edge. */ |
| 2636 | gcc_assert (single_succ_p (bb)); |
| 2637 | gcc_assert (single_succ_edge (bb)->flags |
| 2638 | == (EDGE_SIBCALL | EDGE_ABNORMAL)); |
| 2639 | |
| 2640 | return 0; |
| 2641 | } |
| 2642 | |
| 2643 | /* If we don't see a jump insn, we don't know exactly why the block would |
| 2644 | have been broken at this point. Look for a simple, non-fallthru edge, |
| 2645 | as these are only created by conditional branches. If we find such an |
| 2646 | edge we know that there used to be a jump here and can then safely |
| 2647 | remove all non-fallthru edges. */ |
| 2648 | found = false; |
| 2649 | FOR_EACH_EDGE (e, ei, bb->succs) |
| 2650 | if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))) |
| 2651 | { |
| 2652 | found = true; |
| 2653 | break; |
| 2654 | } |
| 2655 | |
| 2656 | if (!found) |
| 2657 | return purged; |
| 2658 | |
| 2659 | /* Remove all but the fake and fallthru edges. The fake edge may be |
| 2660 | the only successor for this block in the case of noreturn |
| 2661 | calls. */ |
| 2662 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
| 2663 | { |
| 2664 | if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE))) |
| 2665 | { |
| 2666 | df_set_bb_dirty (bb); |
| 2667 | remove_edge (e); |
| 2668 | purged = true; |
| 2669 | } |
| 2670 | else |
| 2671 | ei_next (&ei); |
| 2672 | } |
| 2673 | |
| 2674 | gcc_assert (single_succ_p (bb)); |
| 2675 | |
| 2676 | single_succ_edge (bb)->probability = REG_BR_PROB_BASE; |
| 2677 | single_succ_edge (bb)->count = bb->count; |
| 2678 | |
| 2679 | if (dump_file) |
| 2680 | fprintf (dump_file, "Purged non-fallthru edges from bb %i\n", |
| 2681 | bb->index); |
| 2682 | return purged; |
| 2683 | } |
| 2684 | |
| 2685 | /* Search all basic blocks for potentially dead edges and purge them. Return |
| 2686 | true if some edge has been eliminated. */ |
| 2687 | |
| 2688 | bool |
| 2689 | purge_all_dead_edges (void) |
| 2690 | { |
| 2691 | int purged = false; |
| 2692 | basic_block bb; |
| 2693 | |
| 2694 | FOR_EACH_BB (bb) |
| 2695 | { |
| 2696 | bool purged_here = purge_dead_edges (bb); |
| 2697 | |
| 2698 | purged |= purged_here; |
| 2699 | } |
| 2700 | |
| 2701 | return purged; |
| 2702 | } |
| 2703 | |
| 2704 | /* This is used by a few passes that emit some instructions after abnormal |
| 2705 | calls, moving the basic block's end, while they in fact do want to emit |
| 2706 | them on the fallthru edge. Look for abnormal call edges, find backward |
| 2707 | the call in the block and insert the instructions on the edge instead. |
| 2708 | |
| 2709 | Similarly, handle instructions throwing exceptions internally. |
| 2710 | |
| 2711 | Return true when instructions have been found and inserted on edges. */ |
| 2712 | |
| 2713 | bool |
| 2714 | fixup_abnormal_edges (void) |
| 2715 | { |
| 2716 | bool inserted = false; |
| 2717 | basic_block bb; |
| 2718 | |
| 2719 | FOR_EACH_BB (bb) |
| 2720 | { |
| 2721 | edge e; |
| 2722 | edge_iterator ei; |
| 2723 | |
| 2724 | /* Look for cases we are interested in - calls or instructions causing |
| 2725 | exceptions. */ |
| 2726 | FOR_EACH_EDGE (e, ei, bb->succs) |
| 2727 | if ((e->flags & EDGE_ABNORMAL_CALL) |
| 2728 | || ((e->flags & (EDGE_ABNORMAL | EDGE_EH)) |
| 2729 | == (EDGE_ABNORMAL | EDGE_EH))) |
| 2730 | break; |
| 2731 | |
| 2732 | if (e && !CALL_P (BB_END (bb)) && !can_throw_internal (BB_END (bb))) |
| 2733 | { |
| 2734 | rtx insn; |
| 2735 | |
| 2736 | /* Get past the new insns generated. Allow notes, as the insns |
| 2737 | may be already deleted. */ |
| 2738 | insn = BB_END (bb); |
| 2739 | while ((NONJUMP_INSN_P (insn) || NOTE_P (insn)) |
| 2740 | && !can_throw_internal (insn) |
| 2741 | && insn != BB_HEAD (bb)) |
| 2742 | insn = PREV_INSN (insn); |
| 2743 | |
| 2744 | if (CALL_P (insn) || can_throw_internal (insn)) |
| 2745 | { |
| 2746 | rtx stop, next; |
| 2747 | |
| 2748 | e = find_fallthru_edge (bb->succs); |
| 2749 | |
| 2750 | stop = NEXT_INSN (BB_END (bb)); |
| 2751 | BB_END (bb) = insn; |
| 2752 | |
| 2753 | for (insn = NEXT_INSN (insn); insn != stop; insn = next) |
| 2754 | { |
| 2755 | next = NEXT_INSN (insn); |
| 2756 | if (INSN_P (insn)) |
| 2757 | { |
| 2758 | delete_insn (insn); |
| 2759 | |
| 2760 | /* Sometimes there's still the return value USE. |
| 2761 | If it's placed after a trapping call (i.e. that |
| 2762 | call is the last insn anyway), we have no fallthru |
| 2763 | edge. Simply delete this use and don't try to insert |
| 2764 | on the non-existent edge. */ |
| 2765 | if (GET_CODE (PATTERN (insn)) != USE) |
| 2766 | { |
| 2767 | /* We're not deleting it, we're moving it. */ |
| 2768 | INSN_DELETED_P (insn) = 0; |
| 2769 | PREV_INSN (insn) = NULL_RTX; |
| 2770 | NEXT_INSN (insn) = NULL_RTX; |
| 2771 | |
| 2772 | insert_insn_on_edge (insn, e); |
| 2773 | inserted = true; |
| 2774 | } |
| 2775 | } |
| 2776 | else if (!BARRIER_P (insn)) |
| 2777 | set_block_for_insn (insn, NULL); |
| 2778 | } |
| 2779 | } |
| 2780 | |
| 2781 | /* It may be that we don't find any trapping insn. In this |
| 2782 | case we discovered quite late that the insn that had been |
| 2783 | marked as can_throw_internal in fact couldn't trap at all. |
| 2784 | So we should in fact delete the EH edges out of the block. */ |
| 2785 | else |
| 2786 | purge_dead_edges (bb); |
| 2787 | } |
| 2788 | } |
| 2789 | |
| 2790 | return inserted; |
| 2791 | } |
| 2792 | |
| 2793 | /* Cut the insns from FIRST to LAST out of the insns stream. */ |
| 2794 | |
| 2795 | rtx |
| 2796 | unlink_insn_chain (rtx first, rtx last) |
| 2797 | { |
| 2798 | rtx prevfirst = PREV_INSN (first); |
| 2799 | rtx nextlast = NEXT_INSN (last); |
| 2800 | |
| 2801 | PREV_INSN (first) = NULL; |
| 2802 | NEXT_INSN (last) = NULL; |
| 2803 | if (prevfirst) |
| 2804 | NEXT_INSN (prevfirst) = nextlast; |
| 2805 | if (nextlast) |
| 2806 | PREV_INSN (nextlast) = prevfirst; |
| 2807 | else |
| 2808 | set_last_insn (prevfirst); |
| 2809 | if (!prevfirst) |
| 2810 | set_first_insn (nextlast); |
| 2811 | return first; |
| 2812 | } |
| 2813 | |
| 2814 | /* Skip over inter-block insns occurring after BB which are typically |
| 2815 | associated with BB (e.g., barriers). If there are any such insns, |
| 2816 | we return the last one. Otherwise, we return the end of BB. */ |
| 2817 | |
| 2818 | static rtx |
| 2819 | skip_insns_after_block (basic_block bb) |
| 2820 | { |
| 2821 | rtx insn, last_insn, next_head, prev; |
| 2822 | |
| 2823 | next_head = NULL_RTX; |
| 2824 | if (bb->next_bb != EXIT_BLOCK_PTR) |
| 2825 | next_head = BB_HEAD (bb->next_bb); |
| 2826 | |
| 2827 | for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; ) |
| 2828 | { |
| 2829 | if (insn == next_head) |
| 2830 | break; |
| 2831 | |
| 2832 | switch (GET_CODE (insn)) |
| 2833 | { |
| 2834 | case BARRIER: |
| 2835 | last_insn = insn; |
| 2836 | continue; |
| 2837 | |
| 2838 | case NOTE: |
| 2839 | switch (NOTE_KIND (insn)) |
| 2840 | { |
| 2841 | case NOTE_INSN_BLOCK_END: |
| 2842 | gcc_unreachable (); |
| 2843 | continue; |
| 2844 | default: |
| 2845 | continue; |
| 2846 | break; |
| 2847 | } |
| 2848 | break; |
| 2849 | |
| 2850 | case CODE_LABEL: |
| 2851 | if (NEXT_INSN (insn) |
| 2852 | && JUMP_TABLE_DATA_P (NEXT_INSN (insn))) |
| 2853 | { |
| 2854 | insn = NEXT_INSN (insn); |
| 2855 | last_insn = insn; |
| 2856 | continue; |
| 2857 | } |
| 2858 | break; |
| 2859 | |
| 2860 | default: |
| 2861 | break; |
| 2862 | } |
| 2863 | |
| 2864 | break; |
| 2865 | } |
| 2866 | |
| 2867 | /* It is possible to hit contradictory sequence. For instance: |
| 2868 | |
| 2869 | jump_insn |
| 2870 | NOTE_INSN_BLOCK_BEG |
| 2871 | barrier |
| 2872 | |
| 2873 | Where barrier belongs to jump_insn, but the note does not. This can be |
| 2874 | created by removing the basic block originally following |
| 2875 | NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */ |
| 2876 | |
| 2877 | for (insn = last_insn; insn != BB_END (bb); insn = prev) |
| 2878 | { |
| 2879 | prev = PREV_INSN (insn); |
| 2880 | if (NOTE_P (insn)) |
| 2881 | switch (NOTE_KIND (insn)) |
| 2882 | { |
| 2883 | case NOTE_INSN_BLOCK_END: |
| 2884 | gcc_unreachable (); |
| 2885 | break; |
| 2886 | case NOTE_INSN_DELETED: |
| 2887 | case NOTE_INSN_DELETED_LABEL: |
| 2888 | case NOTE_INSN_DELETED_DEBUG_LABEL: |
| 2889 | continue; |
| 2890 | default: |
| 2891 | reorder_insns (insn, insn, last_insn); |
| 2892 | } |
| 2893 | } |
| 2894 | |
| 2895 | return last_insn; |
| 2896 | } |
| 2897 | |
| 2898 | /* Locate or create a label for a given basic block. */ |
| 2899 | |
| 2900 | static rtx |
| 2901 | label_for_bb (basic_block bb) |
| 2902 | { |
| 2903 | rtx label = BB_HEAD (bb); |
| 2904 | |
| 2905 | if (!LABEL_P (label)) |
| 2906 | { |
| 2907 | if (dump_file) |
| 2908 | fprintf (dump_file, "Emitting label for block %d\n", bb->index); |
| 2909 | |
| 2910 | label = block_label (bb); |
| 2911 | } |
| 2912 | |
| 2913 | return label; |
| 2914 | } |
| 2915 | |
| 2916 | /* Locate the effective beginning and end of the insn chain for each |
| 2917 | block, as defined by skip_insns_after_block above. */ |
| 2918 | |
| 2919 | static void |
| 2920 | record_effective_endpoints (void) |
| 2921 | { |
| 2922 | rtx next_insn; |
| 2923 | basic_block bb; |
| 2924 | rtx insn; |
| 2925 | |
| 2926 | for (insn = get_insns (); |
| 2927 | insn |
| 2928 | && NOTE_P (insn) |
| 2929 | && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK; |
| 2930 | insn = NEXT_INSN (insn)) |
| 2931 | continue; |
| 2932 | /* No basic blocks at all? */ |
| 2933 | gcc_assert (insn); |
| 2934 | |
| 2935 | if (PREV_INSN (insn)) |
| 2936 | cfg_layout_function_header = |
| 2937 | unlink_insn_chain (get_insns (), PREV_INSN (insn)); |
| 2938 | else |
| 2939 | cfg_layout_function_header = NULL_RTX; |
| 2940 | |
| 2941 | next_insn = get_insns (); |
| 2942 | FOR_EACH_BB (bb) |
| 2943 | { |
| 2944 | rtx end; |
| 2945 | |
| 2946 | if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb)) |
| 2947 | BB_HEADER (bb) = unlink_insn_chain (next_insn, |
| 2948 | PREV_INSN (BB_HEAD (bb))); |
| 2949 | end = skip_insns_after_block (bb); |
| 2950 | if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end) |
| 2951 | BB_FOOTER (bb) = unlink_insn_chain (NEXT_INSN (BB_END (bb)), end); |
| 2952 | next_insn = NEXT_INSN (BB_END (bb)); |
| 2953 | } |
| 2954 | |
| 2955 | cfg_layout_function_footer = next_insn; |
| 2956 | if (cfg_layout_function_footer) |
| 2957 | cfg_layout_function_footer = unlink_insn_chain (cfg_layout_function_footer, get_last_insn ()); |
| 2958 | } |
| 2959 | |
| 2960 | static unsigned int |
| 2961 | into_cfg_layout_mode (void) |
| 2962 | { |
| 2963 | cfg_layout_initialize (0); |
| 2964 | return 0; |
| 2965 | } |
| 2966 | |
| 2967 | static unsigned int |
| 2968 | outof_cfg_layout_mode (void) |
| 2969 | { |
| 2970 | basic_block bb; |
| 2971 | |
| 2972 | FOR_EACH_BB (bb) |
| 2973 | if (bb->next_bb != EXIT_BLOCK_PTR) |
| 2974 | bb->aux = bb->next_bb; |
| 2975 | |
| 2976 | cfg_layout_finalize (); |
| 2977 | |
| 2978 | return 0; |
| 2979 | } |
| 2980 | |
| 2981 | struct rtl_opt_pass pass_into_cfg_layout_mode = |
| 2982 | { |
| 2983 | { |
| 2984 | RTL_PASS, |
| 2985 | "into_cfglayout", /* name */ |
| 2986 | NULL, /* gate */ |
| 2987 | into_cfg_layout_mode, /* execute */ |
| 2988 | NULL, /* sub */ |
| 2989 | NULL, /* next */ |
| 2990 | 0, /* static_pass_number */ |
| 2991 | TV_CFG, /* tv_id */ |
| 2992 | 0, /* properties_required */ |
| 2993 | PROP_cfglayout, /* properties_provided */ |
| 2994 | 0, /* properties_destroyed */ |
| 2995 | 0, /* todo_flags_start */ |
| 2996 | 0 /* todo_flags_finish */ |
| 2997 | } |
| 2998 | }; |
| 2999 | |
| 3000 | struct rtl_opt_pass pass_outof_cfg_layout_mode = |
| 3001 | { |
| 3002 | { |
| 3003 | RTL_PASS, |
| 3004 | "outof_cfglayout", /* name */ |
| 3005 | NULL, /* gate */ |
| 3006 | outof_cfg_layout_mode, /* execute */ |
| 3007 | NULL, /* sub */ |
| 3008 | NULL, /* next */ |
| 3009 | 0, /* static_pass_number */ |
| 3010 | TV_CFG, /* tv_id */ |
| 3011 | 0, /* properties_required */ |
| 3012 | 0, /* properties_provided */ |
| 3013 | PROP_cfglayout, /* properties_destroyed */ |
| 3014 | 0, /* todo_flags_start */ |
| 3015 | 0 /* todo_flags_finish */ |
| 3016 | } |
| 3017 | }; |
| 3018 | |
| 3019 | |
| 3020 | /* Link the basic blocks in the correct order, compacting the basic |
| 3021 | block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this |
| 3022 | function also clears the basic block header and footer fields. |
| 3023 | |
| 3024 | This function is usually called after a pass (e.g. tracer) finishes |
| 3025 | some transformations while in cfglayout mode. The required sequence |
| 3026 | of the basic blocks is in a linked list along the bb->aux field. |
| 3027 | This functions re-links the basic block prev_bb and next_bb pointers |
| 3028 | accordingly, and it compacts and renumbers the blocks. |
| 3029 | |
| 3030 | FIXME: This currently works only for RTL, but the only RTL-specific |
| 3031 | bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved |
| 3032 | to GIMPLE a long time ago, but it doesn't relink the basic block |
| 3033 | chain. It could do that (to give better initial RTL) if this function |
| 3034 | is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */ |
| 3035 | |
| 3036 | void |
| 3037 | relink_block_chain (bool stay_in_cfglayout_mode) |
| 3038 | { |
| 3039 | basic_block bb, prev_bb; |
| 3040 | int index; |
| 3041 | |
| 3042 | /* Maybe dump the re-ordered sequence. */ |
| 3043 | if (dump_file) |
| 3044 | { |
| 3045 | fprintf (dump_file, "Reordered sequence:\n"); |
| 3046 | for (bb = ENTRY_BLOCK_PTR->next_bb, index = NUM_FIXED_BLOCKS; |
| 3047 | bb; |
| 3048 | bb = (basic_block) bb->aux, index++) |
| 3049 | { |
| 3050 | fprintf (dump_file, " %i ", index); |
| 3051 | if (get_bb_original (bb)) |
| 3052 | fprintf (dump_file, "duplicate of %i ", |
| 3053 | get_bb_original (bb)->index); |
| 3054 | else if (forwarder_block_p (bb) |
| 3055 | && !LABEL_P (BB_HEAD (bb))) |
| 3056 | fprintf (dump_file, "compensation "); |
| 3057 | else |
| 3058 | fprintf (dump_file, "bb %i ", bb->index); |
| 3059 | fprintf (dump_file, " [%i]\n", bb->frequency); |
| 3060 | } |
| 3061 | } |
| 3062 | |
| 3063 | /* Now reorder the blocks. */ |
| 3064 | prev_bb = ENTRY_BLOCK_PTR; |
| 3065 | bb = ENTRY_BLOCK_PTR->next_bb; |
| 3066 | for (; bb; prev_bb = bb, bb = (basic_block) bb->aux) |
| 3067 | { |
| 3068 | bb->prev_bb = prev_bb; |
| 3069 | prev_bb->next_bb = bb; |
| 3070 | } |
| 3071 | prev_bb->next_bb = EXIT_BLOCK_PTR; |
| 3072 | EXIT_BLOCK_PTR->prev_bb = prev_bb; |
| 3073 | |
| 3074 | /* Then, clean up the aux fields. */ |
| 3075 | FOR_ALL_BB (bb) |
| 3076 | { |
| 3077 | bb->aux = NULL; |
| 3078 | if (!stay_in_cfglayout_mode) |
| 3079 | BB_HEADER (bb) = BB_FOOTER (bb) = NULL; |
| 3080 | } |
| 3081 | |
| 3082 | /* Maybe reset the original copy tables, they are not valid anymore |
| 3083 | when we renumber the basic blocks in compact_blocks. If we are |
| 3084 | are going out of cfglayout mode, don't re-allocate the tables. */ |
| 3085 | free_original_copy_tables (); |
| 3086 | if (stay_in_cfglayout_mode) |
| 3087 | initialize_original_copy_tables (); |
| 3088 | |
| 3089 | /* Finally, put basic_block_info in the new order. */ |
| 3090 | compact_blocks (); |
| 3091 | } |
| 3092 | |
| 3093 | |
| 3094 | /* Given a reorder chain, rearrange the code to match. */ |
| 3095 | |
| 3096 | static void |
| 3097 | fixup_reorder_chain (void) |
| 3098 | { |
| 3099 | basic_block bb; |
| 3100 | rtx insn = NULL; |
| 3101 | |
| 3102 | if (cfg_layout_function_header) |
| 3103 | { |
| 3104 | set_first_insn (cfg_layout_function_header); |
| 3105 | insn = cfg_layout_function_header; |
| 3106 | while (NEXT_INSN (insn)) |
| 3107 | insn = NEXT_INSN (insn); |
| 3108 | } |
| 3109 | |
| 3110 | /* First do the bulk reordering -- rechain the blocks without regard to |
| 3111 | the needed changes to jumps and labels. */ |
| 3112 | |
| 3113 | for (bb = ENTRY_BLOCK_PTR->next_bb; bb; bb = (basic_block) bb->aux) |
| 3114 | { |
| 3115 | if (BB_HEADER (bb)) |
| 3116 | { |
| 3117 | if (insn) |
| 3118 | NEXT_INSN (insn) = BB_HEADER (bb); |
| 3119 | else |
| 3120 | set_first_insn (BB_HEADER (bb)); |
| 3121 | PREV_INSN (BB_HEADER (bb)) = insn; |
| 3122 | insn = BB_HEADER (bb); |
| 3123 | while (NEXT_INSN (insn)) |
| 3124 | insn = NEXT_INSN (insn); |
| 3125 | } |
| 3126 | if (insn) |
| 3127 | NEXT_INSN (insn) = BB_HEAD (bb); |
| 3128 | else |
| 3129 | set_first_insn (BB_HEAD (bb)); |
| 3130 | PREV_INSN (BB_HEAD (bb)) = insn; |
| 3131 | insn = BB_END (bb); |
| 3132 | if (BB_FOOTER (bb)) |
| 3133 | { |
| 3134 | NEXT_INSN (insn) = BB_FOOTER (bb); |
| 3135 | PREV_INSN (BB_FOOTER (bb)) = insn; |
| 3136 | while (NEXT_INSN (insn)) |
| 3137 | insn = NEXT_INSN (insn); |
| 3138 | } |
| 3139 | } |
| 3140 | |
| 3141 | NEXT_INSN (insn) = cfg_layout_function_footer; |
| 3142 | if (cfg_layout_function_footer) |
| 3143 | PREV_INSN (cfg_layout_function_footer) = insn; |
| 3144 | |
| 3145 | while (NEXT_INSN (insn)) |
| 3146 | insn = NEXT_INSN (insn); |
| 3147 | |
| 3148 | set_last_insn (insn); |
| 3149 | #ifdef ENABLE_CHECKING |
| 3150 | verify_insn_chain (); |
| 3151 | #endif |
| 3152 | |
| 3153 | /* Now add jumps and labels as needed to match the blocks new |
| 3154 | outgoing edges. */ |
| 3155 | |
| 3156 | for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = (basic_block) bb->aux) |
| 3157 | { |
| 3158 | edge e_fall, e_taken, e; |
| 3159 | rtx bb_end_insn; |
| 3160 | rtx ret_label = NULL_RTX; |
| 3161 | basic_block nb, src_bb; |
| 3162 | edge_iterator ei; |
| 3163 | |
| 3164 | if (EDGE_COUNT (bb->succs) == 0) |
| 3165 | continue; |
| 3166 | |
| 3167 | /* Find the old fallthru edge, and another non-EH edge for |
| 3168 | a taken jump. */ |
| 3169 | e_taken = e_fall = NULL; |
| 3170 | |
| 3171 | FOR_EACH_EDGE (e, ei, bb->succs) |
| 3172 | if (e->flags & EDGE_FALLTHRU) |
| 3173 | e_fall = e; |
| 3174 | else if (! (e->flags & EDGE_EH)) |
| 3175 | e_taken = e; |
| 3176 | |
| 3177 | bb_end_insn = BB_END (bb); |
| 3178 | if (JUMP_P (bb_end_insn)) |
| 3179 | { |
| 3180 | ret_label = JUMP_LABEL (bb_end_insn); |
| 3181 | if (any_condjump_p (bb_end_insn)) |
| 3182 | { |
| 3183 | /* This might happen if the conditional jump has side |
| 3184 | effects and could therefore not be optimized away. |
| 3185 | Make the basic block to end with a barrier in order |
| 3186 | to prevent rtl_verify_flow_info from complaining. */ |
| 3187 | if (!e_fall) |
| 3188 | { |
| 3189 | gcc_assert (!onlyjump_p (bb_end_insn) |
| 3190 | || returnjump_p (bb_end_insn)); |
| 3191 | BB_FOOTER (bb) = emit_barrier_after (bb_end_insn); |
| 3192 | continue; |
| 3193 | } |
| 3194 | |
| 3195 | /* If the old fallthru is still next, nothing to do. */ |
| 3196 | if (bb->aux == e_fall->dest |
| 3197 | || e_fall->dest == EXIT_BLOCK_PTR) |
| 3198 | continue; |
| 3199 | |
| 3200 | /* The degenerated case of conditional jump jumping to the next |
| 3201 | instruction can happen for jumps with side effects. We need |
| 3202 | to construct a forwarder block and this will be done just |
| 3203 | fine by force_nonfallthru below. */ |
| 3204 | if (!e_taken) |
| 3205 | ; |
| 3206 | |
| 3207 | /* There is another special case: if *neither* block is next, |
| 3208 | such as happens at the very end of a function, then we'll |
| 3209 | need to add a new unconditional jump. Choose the taken |
| 3210 | edge based on known or assumed probability. */ |
| 3211 | else if (bb->aux != e_taken->dest) |
| 3212 | { |
| 3213 | rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0); |
| 3214 | |
| 3215 | if (note |
| 3216 | && INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2 |
| 3217 | && invert_jump (bb_end_insn, |
| 3218 | (e_fall->dest == EXIT_BLOCK_PTR |
| 3219 | ? NULL_RTX |
| 3220 | : label_for_bb (e_fall->dest)), 0)) |
| 3221 | { |
| 3222 | e_fall->flags &= ~EDGE_FALLTHRU; |
| 3223 | gcc_checking_assert (could_fall_through |
| 3224 | (e_taken->src, e_taken->dest)); |
| 3225 | e_taken->flags |= EDGE_FALLTHRU; |
| 3226 | update_br_prob_note (bb); |
| 3227 | e = e_fall, e_fall = e_taken, e_taken = e; |
| 3228 | } |
| 3229 | } |
| 3230 | |
| 3231 | /* If the "jumping" edge is a crossing edge, and the fall |
| 3232 | through edge is non-crossing, leave things as they are. */ |
| 3233 | else if ((e_taken->flags & EDGE_CROSSING) |
| 3234 | && !(e_fall->flags & EDGE_CROSSING)) |
| 3235 | continue; |
| 3236 | |
| 3237 | /* Otherwise we can try to invert the jump. This will |
| 3238 | basically never fail, however, keep up the pretense. */ |
| 3239 | else if (invert_jump (bb_end_insn, |
| 3240 | (e_fall->dest == EXIT_BLOCK_PTR |
| 3241 | ? NULL_RTX |
| 3242 | : label_for_bb (e_fall->dest)), 0)) |
| 3243 | { |
| 3244 | e_fall->flags &= ~EDGE_FALLTHRU; |
| 3245 | gcc_checking_assert (could_fall_through |
| 3246 | (e_taken->src, e_taken->dest)); |
| 3247 | e_taken->flags |= EDGE_FALLTHRU; |
| 3248 | update_br_prob_note (bb); |
| 3249 | if (LABEL_NUSES (ret_label) == 0 |
| 3250 | && single_pred_p (e_taken->dest)) |
| 3251 | delete_insn (ret_label); |
| 3252 | continue; |
| 3253 | } |
| 3254 | } |
| 3255 | else if (extract_asm_operands (PATTERN (bb_end_insn)) != NULL) |
| 3256 | { |
| 3257 | /* If the old fallthru is still next or if |
| 3258 | asm goto doesn't have a fallthru (e.g. when followed by |
| 3259 | __builtin_unreachable ()), nothing to do. */ |
| 3260 | if (! e_fall |
| 3261 | || bb->aux == e_fall->dest |
| 3262 | || e_fall->dest == EXIT_BLOCK_PTR) |
| 3263 | continue; |
| 3264 | |
| 3265 | /* Otherwise we'll have to use the fallthru fixup below. */ |
| 3266 | } |
| 3267 | else |
| 3268 | { |
| 3269 | /* Otherwise we have some return, switch or computed |
| 3270 | jump. In the 99% case, there should not have been a |
| 3271 | fallthru edge. */ |
| 3272 | gcc_assert (returnjump_p (bb_end_insn) || !e_fall); |
| 3273 | continue; |
| 3274 | } |
| 3275 | } |
| 3276 | else |
| 3277 | { |
| 3278 | /* No fallthru implies a noreturn function with EH edges, or |
| 3279 | something similarly bizarre. In any case, we don't need to |
| 3280 | do anything. */ |
| 3281 | if (! e_fall) |
| 3282 | continue; |
| 3283 | |
| 3284 | /* If the fallthru block is still next, nothing to do. */ |
| 3285 | if (bb->aux == e_fall->dest) |
| 3286 | continue; |
| 3287 | |
| 3288 | /* A fallthru to exit block. */ |
| 3289 | if (e_fall->dest == EXIT_BLOCK_PTR) |
| 3290 | continue; |
| 3291 | } |
| 3292 | |
| 3293 | /* We got here if we need to add a new jump insn. |
| 3294 | Note force_nonfallthru can delete E_FALL and thus we have to |
| 3295 | save E_FALL->src prior to the call to force_nonfallthru. */ |
| 3296 | src_bb = e_fall->src; |
| 3297 | nb = force_nonfallthru_and_redirect (e_fall, e_fall->dest, ret_label); |
| 3298 | if (nb) |
| 3299 | { |
| 3300 | nb->aux = bb->aux; |
| 3301 | bb->aux = nb; |
| 3302 | /* Don't process this new block. */ |
| 3303 | bb = nb; |
| 3304 | |
| 3305 | /* Make sure new bb is tagged for correct section (same as |
| 3306 | fall-thru source, since you cannot fall-thru across |
| 3307 | section boundaries). */ |
| 3308 | BB_COPY_PARTITION (src_bb, single_pred (bb)); |
| 3309 | if (flag_reorder_blocks_and_partition |
| 3310 | && targetm_common.have_named_sections |
| 3311 | && JUMP_P (BB_END (bb)) |
| 3312 | && !any_condjump_p (BB_END (bb)) |
| 3313 | && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING)) |
| 3314 | add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX); |
| 3315 | } |
| 3316 | } |
| 3317 | |
| 3318 | relink_block_chain (/*stay_in_cfglayout_mode=*/false); |
| 3319 | |
| 3320 | /* Annoying special case - jump around dead jumptables left in the code. */ |
| 3321 | FOR_EACH_BB (bb) |
| 3322 | { |
| 3323 | edge e = find_fallthru_edge (bb->succs); |
| 3324 | |
| 3325 | if (e && !can_fallthru (e->src, e->dest)) |
| 3326 | force_nonfallthru (e); |
| 3327 | } |
| 3328 | |
| 3329 | /* Ensure goto_locus from edges has some instructions with that locus |
| 3330 | in RTL. */ |
| 3331 | if (!optimize) |
| 3332 | FOR_EACH_BB (bb) |
| 3333 | { |
| 3334 | edge e; |
| 3335 | edge_iterator ei; |
| 3336 | |
| 3337 | FOR_EACH_EDGE (e, ei, bb->succs) |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3338 | if (!IS_UNKNOWN_LOCATION (e->goto_locus) |
| 3339 | && !(e->flags & EDGE_ABNORMAL)) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3340 | { |
| 3341 | edge e2; |
| 3342 | edge_iterator ei2; |
| 3343 | basic_block dest, nb; |
| 3344 | rtx end; |
| 3345 | |
| 3346 | insn = BB_END (e->src); |
| 3347 | end = PREV_INSN (BB_HEAD (e->src)); |
| 3348 | while (insn != end |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3349 | && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn))) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3350 | insn = PREV_INSN (insn); |
| 3351 | if (insn != end |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3352 | && INSN_LOCATION (insn) == e->goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3353 | continue; |
| 3354 | if (simplejump_p (BB_END (e->src)) |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3355 | && !INSN_HAS_LOCATION (BB_END (e->src))) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3356 | { |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3357 | INSN_LOCATION (BB_END (e->src)) = e->goto_locus; |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3358 | continue; |
| 3359 | } |
| 3360 | dest = e->dest; |
| 3361 | if (dest == EXIT_BLOCK_PTR) |
| 3362 | { |
| 3363 | /* Non-fallthru edges to the exit block cannot be split. */ |
| 3364 | if (!(e->flags & EDGE_FALLTHRU)) |
| 3365 | continue; |
| 3366 | } |
| 3367 | else |
| 3368 | { |
| 3369 | insn = BB_HEAD (dest); |
| 3370 | end = NEXT_INSN (BB_END (dest)); |
| 3371 | while (insn != end && !NONDEBUG_INSN_P (insn)) |
| 3372 | insn = NEXT_INSN (insn); |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3373 | if (insn != end && INSN_HAS_LOCATION (insn) |
| 3374 | && INSN_LOCATION (insn) == e->goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3375 | continue; |
| 3376 | } |
| 3377 | nb = split_edge (e); |
| 3378 | if (!INSN_P (BB_END (nb))) |
| 3379 | BB_END (nb) = emit_insn_after_noloc (gen_nop (), BB_END (nb), |
| 3380 | nb); |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3381 | INSN_LOCATION (BB_END (nb)) = e->goto_locus; |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3382 | |
| 3383 | /* If there are other incoming edges to the destination block |
| 3384 | with the same goto locus, redirect them to the new block as |
| 3385 | well, this can prevent other such blocks from being created |
| 3386 | in subsequent iterations of the loop. */ |
| 3387 | for (ei2 = ei_start (dest->preds); (e2 = ei_safe_edge (ei2)); ) |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3388 | if (!IS_UNKNOWN_LOCATION (e2->goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3389 | && !(e2->flags & (EDGE_ABNORMAL | EDGE_FALLTHRU)) |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 3390 | && e->goto_locus == e2->goto_locus) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 3391 | redirect_edge_and_branch (e2, nb); |
| 3392 | else |
| 3393 | ei_next (&ei2); |
| 3394 | } |
| 3395 | } |
| 3396 | } |
| 3397 | |
| 3398 | /* Perform sanity checks on the insn chain. |
| 3399 | 1. Check that next/prev pointers are consistent in both the forward and |
| 3400 | reverse direction. |
| 3401 | 2. Count insns in chain, going both directions, and check if equal. |
| 3402 | 3. Check that get_last_insn () returns the actual end of chain. */ |
| 3403 | |
| 3404 | DEBUG_FUNCTION void |
| 3405 | verify_insn_chain (void) |
| 3406 | { |
| 3407 | rtx x, prevx, nextx; |
| 3408 | int insn_cnt1, insn_cnt2; |
| 3409 | |
| 3410 | for (prevx = NULL, insn_cnt1 = 1, x = get_insns (); |
| 3411 | x != 0; |
| 3412 | prevx = x, insn_cnt1++, x = NEXT_INSN (x)) |
| 3413 | gcc_assert (PREV_INSN (x) == prevx); |
| 3414 | |
| 3415 | gcc_assert (prevx == get_last_insn ()); |
| 3416 | |
| 3417 | for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn (); |
| 3418 | x != 0; |
| 3419 | nextx = x, insn_cnt2++, x = PREV_INSN (x)) |
| 3420 | gcc_assert (NEXT_INSN (x) == nextx); |
| 3421 | |
| 3422 | gcc_assert (insn_cnt1 == insn_cnt2); |
| 3423 | } |
| 3424 | |
| 3425 | /* If we have assembler epilogues, the block falling through to exit must |
| 3426 | be the last one in the reordered chain when we reach final. Ensure |
| 3427 | that this condition is met. */ |
| 3428 | static void |
| 3429 | fixup_fallthru_exit_predecessor (void) |
| 3430 | { |
| 3431 | edge e; |
| 3432 | basic_block bb = NULL; |
| 3433 | |
| 3434 | /* This transformation is not valid before reload, because we might |
| 3435 | separate a call from the instruction that copies the return |
| 3436 | value. */ |
| 3437 | gcc_assert (reload_completed); |
| 3438 | |
| 3439 | e = find_fallthru_edge (EXIT_BLOCK_PTR->preds); |
| 3440 | if (e) |
| 3441 | bb = e->src; |
| 3442 | |
| 3443 | if (bb && bb->aux) |
| 3444 | { |
| 3445 | basic_block c = ENTRY_BLOCK_PTR->next_bb; |
| 3446 | |
| 3447 | /* If the very first block is the one with the fall-through exit |
| 3448 | edge, we have to split that block. */ |
| 3449 | if (c == bb) |
| 3450 | { |
| 3451 | bb = split_block (bb, NULL)->dest; |
| 3452 | bb->aux = c->aux; |
| 3453 | c->aux = bb; |
| 3454 | BB_FOOTER (bb) = BB_FOOTER (c); |
| 3455 | BB_FOOTER (c) = NULL; |
| 3456 | } |
| 3457 | |
| 3458 | while (c->aux != bb) |
| 3459 | c = (basic_block) c->aux; |
| 3460 | |
| 3461 | c->aux = bb->aux; |
| 3462 | while (c->aux) |
| 3463 | c = (basic_block) c->aux; |
| 3464 | |
| 3465 | c->aux = bb; |
| 3466 | bb->aux = NULL; |
| 3467 | } |
| 3468 | } |
| 3469 | |
| 3470 | /* In case there are more than one fallthru predecessors of exit, force that |
| 3471 | there is only one. */ |
| 3472 | |
| 3473 | static void |
| 3474 | force_one_exit_fallthru (void) |
| 3475 | { |
| 3476 | edge e, predecessor = NULL; |
| 3477 | bool more = false; |
| 3478 | edge_iterator ei; |
| 3479 | basic_block forwarder, bb; |
| 3480 | |
| 3481 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) |
| 3482 | if (e->flags & EDGE_FALLTHRU) |
| 3483 | { |
| 3484 | if (predecessor == NULL) |
| 3485 | predecessor = e; |
| 3486 | else |
| 3487 | { |
| 3488 | more = true; |
| 3489 | break; |
| 3490 | } |
| 3491 | } |
| 3492 | |
| 3493 | if (!more) |
| 3494 | return; |
| 3495 | |
| 3496 | /* Exit has several fallthru predecessors. Create a forwarder block for |
| 3497 | them. */ |
| 3498 | forwarder = split_edge (predecessor); |
| 3499 | for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); ) |
| 3500 | { |
| 3501 | if (e->src == forwarder |
| 3502 | || !(e->flags & EDGE_FALLTHRU)) |
| 3503 | ei_next (&ei); |
| 3504 | else |
| 3505 | redirect_edge_and_branch_force (e, forwarder); |
| 3506 | } |
| 3507 | |
| 3508 | /* Fix up the chain of blocks -- make FORWARDER immediately precede the |
| 3509 | exit block. */ |
| 3510 | FOR_EACH_BB (bb) |
| 3511 | { |
| 3512 | if (bb->aux == NULL && bb != forwarder) |
| 3513 | { |
| 3514 | bb->aux = forwarder; |
| 3515 | break; |
| 3516 | } |
| 3517 | } |
| 3518 | } |
| 3519 | |
| 3520 | /* Return true in case it is possible to duplicate the basic block BB. */ |
| 3521 | |
| 3522 | static bool |
| 3523 | cfg_layout_can_duplicate_bb_p (const_basic_block bb) |
| 3524 | { |
| 3525 | /* Do not attempt to duplicate tablejumps, as we need to unshare |
| 3526 | the dispatch table. This is difficult to do, as the instructions |
| 3527 | computing jump destination may be hoisted outside the basic block. */ |
| 3528 | if (tablejump_p (BB_END (bb), NULL, NULL)) |
| 3529 | return false; |
| 3530 | |
| 3531 | /* Do not duplicate blocks containing insns that can't be copied. */ |
| 3532 | if (targetm.cannot_copy_insn_p) |
| 3533 | { |
| 3534 | rtx insn = BB_HEAD (bb); |
| 3535 | while (1) |
| 3536 | { |
| 3537 | if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn)) |
| 3538 | return false; |
| 3539 | if (insn == BB_END (bb)) |
| 3540 | break; |
| 3541 | insn = NEXT_INSN (insn); |
| 3542 | } |
| 3543 | } |
| 3544 | |
| 3545 | return true; |
| 3546 | } |
| 3547 | |
| 3548 | rtx |
| 3549 | duplicate_insn_chain (rtx from, rtx to) |
| 3550 | { |
| 3551 | rtx insn, last, copy; |
| 3552 | |
| 3553 | /* Avoid updating of boundaries of previous basic block. The |
| 3554 | note will get removed from insn stream in fixup. */ |
| 3555 | last = emit_note (NOTE_INSN_DELETED); |
| 3556 | |
| 3557 | /* Create copy at the end of INSN chain. The chain will |
| 3558 | be reordered later. */ |
| 3559 | for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn)) |
| 3560 | { |
| 3561 | switch (GET_CODE (insn)) |
| 3562 | { |
| 3563 | case DEBUG_INSN: |
| 3564 | /* Don't duplicate label debug insns. */ |
| 3565 | if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn)) == LABEL_DECL) |
| 3566 | break; |
| 3567 | /* FALLTHRU */ |
| 3568 | case INSN: |
| 3569 | case CALL_INSN: |
| 3570 | case JUMP_INSN: |
| 3571 | /* Avoid copying of dispatch tables. We never duplicate |
| 3572 | tablejumps, so this can hit only in case the table got |
| 3573 | moved far from original jump. */ |
| 3574 | if (GET_CODE (PATTERN (insn)) == ADDR_VEC |
| 3575 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC) |
| 3576 | { |
| 3577 | /* Avoid copying following barrier as well if any |
| 3578 | (and debug insns in between). */ |
| 3579 | rtx next; |
| 3580 | |
| 3581 | for (next = NEXT_INSN (insn); |
| 3582 | next != NEXT_INSN (to); |
| 3583 | next = NEXT_INSN (next)) |
| 3584 | if (!DEBUG_INSN_P (next)) |
| 3585 | break; |
| 3586 | if (next != NEXT_INSN (to) && BARRIER_P (next)) |
| 3587 | insn = next; |
| 3588 | break; |
| 3589 | } |
| 3590 | copy = emit_copy_of_insn_after (insn, get_last_insn ()); |
| 3591 | if (JUMP_P (insn) && JUMP_LABEL (insn) != NULL_RTX |
| 3592 | && ANY_RETURN_P (JUMP_LABEL (insn))) |
| 3593 | JUMP_LABEL (copy) = JUMP_LABEL (insn); |
| 3594 | maybe_copy_prologue_epilogue_insn (insn, copy); |
| 3595 | break; |
| 3596 | |
| 3597 | case CODE_LABEL: |
| 3598 | break; |
| 3599 | |
| 3600 | case BARRIER: |
| 3601 | emit_barrier (); |
| 3602 | break; |
| 3603 | |
| 3604 | case NOTE: |
| 3605 | switch (NOTE_KIND (insn)) |
| 3606 | { |
| 3607 | /* In case prologue is empty and function contain label |
| 3608 | in first BB, we may want to copy the block. */ |
| 3609 | case NOTE_INSN_PROLOGUE_END: |
| 3610 | |
| 3611 | case NOTE_INSN_DELETED: |
| 3612 | case NOTE_INSN_DELETED_LABEL: |
| 3613 | case NOTE_INSN_DELETED_DEBUG_LABEL: |
| 3614 | /* No problem to strip these. */ |
| 3615 | case NOTE_INSN_FUNCTION_BEG: |
| 3616 | /* There is always just single entry to function. */ |
| 3617 | case NOTE_INSN_BASIC_BLOCK: |
| 3618 | break; |
| 3619 | |
| 3620 | case NOTE_INSN_EPILOGUE_BEG: |
| 3621 | case NOTE_INSN_SWITCH_TEXT_SECTIONS: |
| 3622 | emit_note_copy (insn); |
| 3623 | break; |
| 3624 | |
| 3625 | default: |
| 3626 | /* All other notes should have already been eliminated. */ |
| 3627 | gcc_unreachable (); |
| 3628 | } |
| 3629 | break; |
| 3630 | default: |
| 3631 | gcc_unreachable (); |
| 3632 | } |
| 3633 | } |
| 3634 | insn = NEXT_INSN (last); |
| 3635 | delete_insn (last); |
| 3636 | return insn; |
| 3637 | } |
| 3638 | |
| 3639 | /* Create a duplicate of the basic block BB. */ |
| 3640 | |
| 3641 | static basic_block |
| 3642 | cfg_layout_duplicate_bb (basic_block bb) |
| 3643 | { |
| 3644 | rtx insn; |
| 3645 | basic_block new_bb; |
| 3646 | |
| 3647 | insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb)); |
| 3648 | new_bb = create_basic_block (insn, |
| 3649 | insn ? get_last_insn () : NULL, |
| 3650 | EXIT_BLOCK_PTR->prev_bb); |
| 3651 | |
| 3652 | BB_COPY_PARTITION (new_bb, bb); |
| 3653 | if (BB_HEADER (bb)) |
| 3654 | { |
| 3655 | insn = BB_HEADER (bb); |
| 3656 | while (NEXT_INSN (insn)) |
| 3657 | insn = NEXT_INSN (insn); |
| 3658 | insn = duplicate_insn_chain (BB_HEADER (bb), insn); |
| 3659 | if (insn) |
| 3660 | BB_HEADER (new_bb) = unlink_insn_chain (insn, get_last_insn ()); |
| 3661 | } |
| 3662 | |
| 3663 | if (BB_FOOTER (bb)) |
| 3664 | { |
| 3665 | insn = BB_FOOTER (bb); |
| 3666 | while (NEXT_INSN (insn)) |
| 3667 | insn = NEXT_INSN (insn); |
| 3668 | insn = duplicate_insn_chain (BB_FOOTER (bb), insn); |
| 3669 | if (insn) |
| 3670 | BB_FOOTER (new_bb) = unlink_insn_chain (insn, get_last_insn ()); |
| 3671 | } |
| 3672 | |
| 3673 | return new_bb; |
| 3674 | } |
| 3675 | |
| 3676 | |
| 3677 | /* Main entry point to this module - initialize the datastructures for |
| 3678 | CFG layout changes. It keeps LOOPS up-to-date if not null. |
| 3679 | |
| 3680 | FLAGS is a set of additional flags to pass to cleanup_cfg(). */ |
| 3681 | |
| 3682 | void |
| 3683 | cfg_layout_initialize (unsigned int flags) |
| 3684 | { |
| 3685 | rtx x; |
| 3686 | basic_block bb; |
| 3687 | |
| 3688 | initialize_original_copy_tables (); |
| 3689 | |
| 3690 | cfg_layout_rtl_register_cfg_hooks (); |
| 3691 | |
| 3692 | record_effective_endpoints (); |
| 3693 | |
| 3694 | /* Make sure that the targets of non local gotos are marked. */ |
| 3695 | for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1)) |
| 3696 | { |
| 3697 | bb = BLOCK_FOR_INSN (XEXP (x, 0)); |
| 3698 | bb->flags |= BB_NON_LOCAL_GOTO_TARGET; |
| 3699 | } |
| 3700 | |
| 3701 | cleanup_cfg (CLEANUP_CFGLAYOUT | flags); |
| 3702 | } |
| 3703 | |
| 3704 | /* Splits superblocks. */ |
| 3705 | void |
| 3706 | break_superblocks (void) |
| 3707 | { |
| 3708 | sbitmap superblocks; |
| 3709 | bool need = false; |
| 3710 | basic_block bb; |
| 3711 | |
| 3712 | superblocks = sbitmap_alloc (last_basic_block); |
| 3713 | sbitmap_zero (superblocks); |
| 3714 | |
| 3715 | FOR_EACH_BB (bb) |
| 3716 | if (bb->flags & BB_SUPERBLOCK) |
| 3717 | { |
| 3718 | bb->flags &= ~BB_SUPERBLOCK; |
| 3719 | SET_BIT (superblocks, bb->index); |
| 3720 | need = true; |
| 3721 | } |
| 3722 | |
| 3723 | if (need) |
| 3724 | { |
| 3725 | rebuild_jump_labels (get_insns ()); |
| 3726 | find_many_sub_basic_blocks (superblocks); |
| 3727 | } |
| 3728 | |
| 3729 | free (superblocks); |
| 3730 | } |
| 3731 | |
| 3732 | /* Finalize the changes: reorder insn list according to the sequence specified |
| 3733 | by aux pointers, enter compensation code, rebuild scope forest. */ |
| 3734 | |
| 3735 | void |
| 3736 | cfg_layout_finalize (void) |
| 3737 | { |
| 3738 | #ifdef ENABLE_CHECKING |
| 3739 | verify_flow_info (); |
| 3740 | #endif |
| 3741 | force_one_exit_fallthru (); |
| 3742 | rtl_register_cfg_hooks (); |
| 3743 | if (reload_completed |
| 3744 | #ifdef HAVE_epilogue |
| 3745 | && !HAVE_epilogue |
| 3746 | #endif |
| 3747 | ) |
| 3748 | fixup_fallthru_exit_predecessor (); |
| 3749 | fixup_reorder_chain (); |
| 3750 | |
| 3751 | rebuild_jump_labels (get_insns ()); |
| 3752 | delete_dead_jumptables (); |
| 3753 | |
| 3754 | #ifdef ENABLE_CHECKING |
| 3755 | verify_insn_chain (); |
| 3756 | verify_flow_info (); |
| 3757 | #endif |
| 3758 | } |
| 3759 | |
| 3760 | |
| 3761 | /* Same as split_block but update cfg_layout structures. */ |
| 3762 | |
| 3763 | static basic_block |
| 3764 | cfg_layout_split_block (basic_block bb, void *insnp) |
| 3765 | { |
| 3766 | rtx insn = (rtx) insnp; |
| 3767 | basic_block new_bb = rtl_split_block (bb, insn); |
| 3768 | |
| 3769 | BB_FOOTER (new_bb) = BB_FOOTER (bb); |
| 3770 | BB_FOOTER (bb) = NULL; |
| 3771 | |
| 3772 | return new_bb; |
| 3773 | } |
| 3774 | |
| 3775 | /* Redirect Edge to DEST. */ |
| 3776 | static edge |
| 3777 | cfg_layout_redirect_edge_and_branch (edge e, basic_block dest) |
| 3778 | { |
| 3779 | basic_block src = e->src; |
| 3780 | edge ret; |
| 3781 | |
| 3782 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
| 3783 | return NULL; |
| 3784 | |
| 3785 | if (e->dest == dest) |
| 3786 | return e; |
| 3787 | |
| 3788 | if (e->src != ENTRY_BLOCK_PTR |
| 3789 | && (ret = try_redirect_by_replacing_jump (e, dest, true))) |
| 3790 | { |
| 3791 | df_set_bb_dirty (src); |
| 3792 | return ret; |
| 3793 | } |
| 3794 | |
| 3795 | if (e->src == ENTRY_BLOCK_PTR |
| 3796 | && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX)) |
| 3797 | { |
| 3798 | if (dump_file) |
| 3799 | fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n", |
| 3800 | e->src->index, dest->index); |
| 3801 | |
| 3802 | df_set_bb_dirty (e->src); |
| 3803 | redirect_edge_succ (e, dest); |
| 3804 | return e; |
| 3805 | } |
| 3806 | |
| 3807 | /* Redirect_edge_and_branch may decide to turn branch into fallthru edge |
| 3808 | in the case the basic block appears to be in sequence. Avoid this |
| 3809 | transformation. */ |
| 3810 | |
| 3811 | if (e->flags & EDGE_FALLTHRU) |
| 3812 | { |
| 3813 | /* Redirect any branch edges unified with the fallthru one. */ |
| 3814 | if (JUMP_P (BB_END (src)) |
| 3815 | && label_is_jump_target_p (BB_HEAD (e->dest), |
| 3816 | BB_END (src))) |
| 3817 | { |
| 3818 | edge redirected; |
| 3819 | |
| 3820 | if (dump_file) |
| 3821 | fprintf (dump_file, "Fallthru edge unified with branch " |
| 3822 | "%i->%i redirected to %i\n", |
| 3823 | e->src->index, e->dest->index, dest->index); |
| 3824 | e->flags &= ~EDGE_FALLTHRU; |
| 3825 | redirected = redirect_branch_edge (e, dest); |
| 3826 | gcc_assert (redirected); |
| 3827 | redirected->flags |= EDGE_FALLTHRU; |
| 3828 | df_set_bb_dirty (redirected->src); |
| 3829 | return redirected; |
| 3830 | } |
| 3831 | /* In case we are redirecting fallthru edge to the branch edge |
| 3832 | of conditional jump, remove it. */ |
| 3833 | if (EDGE_COUNT (src->succs) == 2) |
| 3834 | { |
| 3835 | /* Find the edge that is different from E. */ |
| 3836 | edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e); |
| 3837 | |
| 3838 | if (s->dest == dest |
| 3839 | && any_condjump_p (BB_END (src)) |
| 3840 | && onlyjump_p (BB_END (src))) |
| 3841 | delete_insn (BB_END (src)); |
| 3842 | } |
| 3843 | if (dump_file) |
| 3844 | fprintf (dump_file, "Redirecting fallthru edge %i->%i to %i\n", |
| 3845 | e->src->index, e->dest->index, dest->index); |
| 3846 | ret = redirect_edge_succ_nodup (e, dest); |
| 3847 | } |
| 3848 | else |
| 3849 | ret = redirect_branch_edge (e, dest); |
| 3850 | |
| 3851 | /* We don't want simplejumps in the insn stream during cfglayout. */ |
| 3852 | gcc_assert (!simplejump_p (BB_END (src))); |
| 3853 | |
| 3854 | df_set_bb_dirty (src); |
| 3855 | return ret; |
| 3856 | } |
| 3857 | |
| 3858 | /* Simple wrapper as we always can redirect fallthru edges. */ |
| 3859 | static basic_block |
| 3860 | cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest) |
| 3861 | { |
| 3862 | edge redirected = cfg_layout_redirect_edge_and_branch (e, dest); |
| 3863 | |
| 3864 | gcc_assert (redirected); |
| 3865 | return NULL; |
| 3866 | } |
| 3867 | |
| 3868 | /* Same as delete_basic_block but update cfg_layout structures. */ |
| 3869 | |
| 3870 | static void |
| 3871 | cfg_layout_delete_block (basic_block bb) |
| 3872 | { |
| 3873 | rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints; |
| 3874 | |
| 3875 | if (BB_HEADER (bb)) |
| 3876 | { |
| 3877 | next = BB_HEAD (bb); |
| 3878 | if (prev) |
| 3879 | NEXT_INSN (prev) = BB_HEADER (bb); |
| 3880 | else |
| 3881 | set_first_insn (BB_HEADER (bb)); |
| 3882 | PREV_INSN (BB_HEADER (bb)) = prev; |
| 3883 | insn = BB_HEADER (bb); |
| 3884 | while (NEXT_INSN (insn)) |
| 3885 | insn = NEXT_INSN (insn); |
| 3886 | NEXT_INSN (insn) = next; |
| 3887 | PREV_INSN (next) = insn; |
| 3888 | } |
| 3889 | next = NEXT_INSN (BB_END (bb)); |
| 3890 | if (BB_FOOTER (bb)) |
| 3891 | { |
| 3892 | insn = BB_FOOTER (bb); |
| 3893 | while (insn) |
| 3894 | { |
| 3895 | if (BARRIER_P (insn)) |
| 3896 | { |
| 3897 | if (PREV_INSN (insn)) |
| 3898 | NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); |
| 3899 | else |
| 3900 | BB_FOOTER (bb) = NEXT_INSN (insn); |
| 3901 | if (NEXT_INSN (insn)) |
| 3902 | PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); |
| 3903 | } |
| 3904 | if (LABEL_P (insn)) |
| 3905 | break; |
| 3906 | insn = NEXT_INSN (insn); |
| 3907 | } |
| 3908 | if (BB_FOOTER (bb)) |
| 3909 | { |
| 3910 | insn = BB_END (bb); |
| 3911 | NEXT_INSN (insn) = BB_FOOTER (bb); |
| 3912 | PREV_INSN (BB_FOOTER (bb)) = insn; |
| 3913 | while (NEXT_INSN (insn)) |
| 3914 | insn = NEXT_INSN (insn); |
| 3915 | NEXT_INSN (insn) = next; |
| 3916 | if (next) |
| 3917 | PREV_INSN (next) = insn; |
| 3918 | else |
| 3919 | set_last_insn (insn); |
| 3920 | } |
| 3921 | } |
| 3922 | if (bb->next_bb != EXIT_BLOCK_PTR) |
| 3923 | to = &BB_HEADER (bb->next_bb); |
| 3924 | else |
| 3925 | to = &cfg_layout_function_footer; |
| 3926 | |
| 3927 | rtl_delete_block (bb); |
| 3928 | |
| 3929 | if (prev) |
| 3930 | prev = NEXT_INSN (prev); |
| 3931 | else |
| 3932 | prev = get_insns (); |
| 3933 | if (next) |
| 3934 | next = PREV_INSN (next); |
| 3935 | else |
| 3936 | next = get_last_insn (); |
| 3937 | |
| 3938 | if (next && NEXT_INSN (next) != prev) |
| 3939 | { |
| 3940 | remaints = unlink_insn_chain (prev, next); |
| 3941 | insn = remaints; |
| 3942 | while (NEXT_INSN (insn)) |
| 3943 | insn = NEXT_INSN (insn); |
| 3944 | NEXT_INSN (insn) = *to; |
| 3945 | if (*to) |
| 3946 | PREV_INSN (*to) = insn; |
| 3947 | *to = remaints; |
| 3948 | } |
| 3949 | } |
| 3950 | |
| 3951 | /* Return true when blocks A and B can be safely merged. */ |
| 3952 | |
| 3953 | static bool |
| 3954 | cfg_layout_can_merge_blocks_p (basic_block a, basic_block b) |
| 3955 | { |
| 3956 | /* If we are partitioning hot/cold basic blocks, we don't want to |
| 3957 | mess up unconditional or indirect jumps that cross between hot |
| 3958 | and cold sections. |
| 3959 | |
| 3960 | Basic block partitioning may result in some jumps that appear to |
| 3961 | be optimizable (or blocks that appear to be mergeable), but which really |
| 3962 | must be left untouched (they are required to make it safely across |
| 3963 | partition boundaries). See the comments at the top of |
| 3964 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
| 3965 | |
| 3966 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
| 3967 | return false; |
| 3968 | |
| 3969 | /* Protect the loop latches. */ |
| 3970 | if (current_loops && b->loop_father->latch == b) |
| 3971 | return false; |
| 3972 | |
| 3973 | /* If we would end up moving B's instructions, make sure it doesn't fall |
| 3974 | through into the exit block, since we cannot recover from a fallthrough |
| 3975 | edge into the exit block occurring in the middle of a function. */ |
| 3976 | if (NEXT_INSN (BB_END (a)) != BB_HEAD (b)) |
| 3977 | { |
| 3978 | edge e = find_fallthru_edge (b->succs); |
| 3979 | if (e && e->dest == EXIT_BLOCK_PTR) |
| 3980 | return false; |
| 3981 | } |
| 3982 | |
| 3983 | /* There must be exactly one edge in between the blocks. */ |
| 3984 | return (single_succ_p (a) |
| 3985 | && single_succ (a) == b |
| 3986 | && single_pred_p (b) == 1 |
| 3987 | && a != b |
| 3988 | /* Must be simple edge. */ |
| 3989 | && !(single_succ_edge (a)->flags & EDGE_COMPLEX) |
| 3990 | && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR |
| 3991 | /* If the jump insn has side effects, we can't kill the edge. |
| 3992 | When not optimizing, try_redirect_by_replacing_jump will |
| 3993 | not allow us to redirect an edge by replacing a table jump. */ |
| 3994 | && (!JUMP_P (BB_END (a)) |
| 3995 | || ((!optimize || reload_completed) |
| 3996 | ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a))))); |
| 3997 | } |
| 3998 | |
| 3999 | /* Merge block A and B. The blocks must be mergeable. */ |
| 4000 | |
| 4001 | static void |
| 4002 | cfg_layout_merge_blocks (basic_block a, basic_block b) |
| 4003 | { |
| 4004 | bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0; |
| 4005 | rtx insn; |
| 4006 | |
| 4007 | gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b)); |
| 4008 | |
| 4009 | if (dump_file) |
| 4010 | fprintf (dump_file, "Merging block %d into block %d...\n", b->index, |
| 4011 | a->index); |
| 4012 | |
| 4013 | /* If there was a CODE_LABEL beginning B, delete it. */ |
| 4014 | if (LABEL_P (BB_HEAD (b))) |
| 4015 | { |
| 4016 | delete_insn (BB_HEAD (b)); |
| 4017 | } |
| 4018 | |
| 4019 | /* We should have fallthru edge in a, or we can do dummy redirection to get |
| 4020 | it cleaned up. */ |
| 4021 | if (JUMP_P (BB_END (a))) |
| 4022 | try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true); |
| 4023 | gcc_assert (!JUMP_P (BB_END (a))); |
| 4024 | |
| 4025 | /* When not optimizing CFG and the edge is the only place in RTL which holds |
| 4026 | some unique locus, emit a nop with that locus in between. */ |
| 4027 | if (!optimize) |
| 4028 | emit_nop_for_unique_locus_between (a, b); |
| 4029 | |
| 4030 | /* Possible line number notes should appear in between. */ |
| 4031 | if (BB_HEADER (b)) |
| 4032 | { |
| 4033 | rtx first = BB_END (a), last; |
| 4034 | |
| 4035 | last = emit_insn_after_noloc (BB_HEADER (b), BB_END (a), a); |
| 4036 | /* The above might add a BARRIER as BB_END, but as barriers |
| 4037 | aren't valid parts of a bb, remove_insn doesn't update |
| 4038 | BB_END if it is a barrier. So adjust BB_END here. */ |
| 4039 | while (BB_END (a) != first && BARRIER_P (BB_END (a))) |
| 4040 | BB_END (a) = PREV_INSN (BB_END (a)); |
| 4041 | delete_insn_chain (NEXT_INSN (first), last, false); |
| 4042 | BB_HEADER (b) = NULL; |
| 4043 | } |
| 4044 | |
| 4045 | /* In the case basic blocks are not adjacent, move them around. */ |
| 4046 | if (NEXT_INSN (BB_END (a)) != BB_HEAD (b)) |
| 4047 | { |
| 4048 | insn = unlink_insn_chain (BB_HEAD (b), BB_END (b)); |
| 4049 | |
| 4050 | emit_insn_after_noloc (insn, BB_END (a), a); |
| 4051 | } |
| 4052 | /* Otherwise just re-associate the instructions. */ |
| 4053 | else |
| 4054 | { |
| 4055 | insn = BB_HEAD (b); |
| 4056 | BB_END (a) = BB_END (b); |
| 4057 | } |
| 4058 | |
| 4059 | /* emit_insn_after_noloc doesn't call df_insn_change_bb. |
| 4060 | We need to explicitly call. */ |
| 4061 | update_bb_for_insn_chain (insn, BB_END (b), a); |
| 4062 | |
| 4063 | /* Skip possible DELETED_LABEL insn. */ |
| 4064 | if (!NOTE_INSN_BASIC_BLOCK_P (insn)) |
| 4065 | insn = NEXT_INSN (insn); |
| 4066 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn)); |
| 4067 | BB_HEAD (b) = NULL; |
| 4068 | delete_insn (insn); |
| 4069 | |
| 4070 | df_bb_delete (b->index); |
| 4071 | |
| 4072 | /* Possible tablejumps and barriers should appear after the block. */ |
| 4073 | if (BB_FOOTER (b)) |
| 4074 | { |
| 4075 | if (!BB_FOOTER (a)) |
| 4076 | BB_FOOTER (a) = BB_FOOTER (b); |
| 4077 | else |
| 4078 | { |
| 4079 | rtx last = BB_FOOTER (a); |
| 4080 | |
| 4081 | while (NEXT_INSN (last)) |
| 4082 | last = NEXT_INSN (last); |
| 4083 | NEXT_INSN (last) = BB_FOOTER (b); |
| 4084 | PREV_INSN (BB_FOOTER (b)) = last; |
| 4085 | } |
| 4086 | BB_FOOTER (b) = NULL; |
| 4087 | } |
| 4088 | |
| 4089 | /* If B was a forwarder block, propagate the locus on the edge. */ |
Bernhard Rosenkraenzer | 84c1139 | 2012-09-27 01:39:09 +0159 | [diff] [blame^] | 4090 | if (forwarder_p && IS_UNKNOWN_LOCATION (EDGE_SUCC (b, 0)->goto_locus)) |
Bernhard Rosenkraenzer | c83ebe5 | 2012-09-18 21:38:03 +0159 | [diff] [blame] | 4091 | EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
| 4092 | |
| 4093 | if (dump_file) |
| 4094 | fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index); |
| 4095 | } |
| 4096 | |
| 4097 | /* Split edge E. */ |
| 4098 | |
| 4099 | static basic_block |
| 4100 | cfg_layout_split_edge (edge e) |
| 4101 | { |
| 4102 | basic_block new_bb = |
| 4103 | create_basic_block (e->src != ENTRY_BLOCK_PTR |
| 4104 | ? NEXT_INSN (BB_END (e->src)) : get_insns (), |
| 4105 | NULL_RTX, e->src); |
| 4106 | |
| 4107 | if (e->dest == EXIT_BLOCK_PTR) |
| 4108 | BB_COPY_PARTITION (new_bb, e->src); |
| 4109 | else |
| 4110 | BB_COPY_PARTITION (new_bb, e->dest); |
| 4111 | make_edge (new_bb, e->dest, EDGE_FALLTHRU); |
| 4112 | redirect_edge_and_branch_force (e, new_bb); |
| 4113 | |
| 4114 | return new_bb; |
| 4115 | } |
| 4116 | |
| 4117 | /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */ |
| 4118 | |
| 4119 | static void |
| 4120 | rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED) |
| 4121 | { |
| 4122 | } |
| 4123 | |
| 4124 | /* Return true if BB contains only labels or non-executable |
| 4125 | instructions. */ |
| 4126 | |
| 4127 | static bool |
| 4128 | rtl_block_empty_p (basic_block bb) |
| 4129 | { |
| 4130 | rtx insn; |
| 4131 | |
| 4132 | if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR) |
| 4133 | return true; |
| 4134 | |
| 4135 | FOR_BB_INSNS (bb, insn) |
| 4136 | if (NONDEBUG_INSN_P (insn) && !any_uncondjump_p (insn)) |
| 4137 | return false; |
| 4138 | |
| 4139 | return true; |
| 4140 | } |
| 4141 | |
| 4142 | /* Split a basic block if it ends with a conditional branch and if |
| 4143 | the other part of the block is not empty. */ |
| 4144 | |
| 4145 | static basic_block |
| 4146 | rtl_split_block_before_cond_jump (basic_block bb) |
| 4147 | { |
| 4148 | rtx insn; |
| 4149 | rtx split_point = NULL; |
| 4150 | rtx last = NULL; |
| 4151 | bool found_code = false; |
| 4152 | |
| 4153 | FOR_BB_INSNS (bb, insn) |
| 4154 | { |
| 4155 | if (any_condjump_p (insn)) |
| 4156 | split_point = last; |
| 4157 | else if (NONDEBUG_INSN_P (insn)) |
| 4158 | found_code = true; |
| 4159 | last = insn; |
| 4160 | } |
| 4161 | |
| 4162 | /* Did not find everything. */ |
| 4163 | if (found_code && split_point) |
| 4164 | return split_block (bb, split_point)->dest; |
| 4165 | else |
| 4166 | return NULL; |
| 4167 | } |
| 4168 | |
| 4169 | /* Return 1 if BB ends with a call, possibly followed by some |
| 4170 | instructions that must stay with the call, 0 otherwise. */ |
| 4171 | |
| 4172 | static bool |
| 4173 | rtl_block_ends_with_call_p (basic_block bb) |
| 4174 | { |
| 4175 | rtx insn = BB_END (bb); |
| 4176 | |
| 4177 | while (!CALL_P (insn) |
| 4178 | && insn != BB_HEAD (bb) |
| 4179 | && (keep_with_call_p (insn) |
| 4180 | || NOTE_P (insn) |
| 4181 | || DEBUG_INSN_P (insn))) |
| 4182 | insn = PREV_INSN (insn); |
| 4183 | return (CALL_P (insn)); |
| 4184 | } |
| 4185 | |
| 4186 | /* Return 1 if BB ends with a conditional branch, 0 otherwise. */ |
| 4187 | |
| 4188 | static bool |
| 4189 | rtl_block_ends_with_condjump_p (const_basic_block bb) |
| 4190 | { |
| 4191 | return any_condjump_p (BB_END (bb)); |
| 4192 | } |
| 4193 | |
| 4194 | /* Return true if we need to add fake edge to exit. |
| 4195 | Helper function for rtl_flow_call_edges_add. */ |
| 4196 | |
| 4197 | static bool |
| 4198 | need_fake_edge_p (const_rtx insn) |
| 4199 | { |
| 4200 | if (!INSN_P (insn)) |
| 4201 | return false; |
| 4202 | |
| 4203 | if ((CALL_P (insn) |
| 4204 | && !SIBLING_CALL_P (insn) |
| 4205 | && !find_reg_note (insn, REG_NORETURN, NULL) |
| 4206 | && !(RTL_CONST_OR_PURE_CALL_P (insn)))) |
| 4207 | return true; |
| 4208 | |
| 4209 | return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS |
| 4210 | && MEM_VOLATILE_P (PATTERN (insn))) |
| 4211 | || (GET_CODE (PATTERN (insn)) == PARALLEL |
| 4212 | && asm_noperands (insn) != -1 |
| 4213 | && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0))) |
| 4214 | || GET_CODE (PATTERN (insn)) == ASM_INPUT); |
| 4215 | } |
| 4216 | |
| 4217 | /* Add fake edges to the function exit for any non constant and non noreturn |
| 4218 | calls, volatile inline assembly in the bitmap of blocks specified by |
| 4219 | BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks |
| 4220 | that were split. |
| 4221 | |
| 4222 | The goal is to expose cases in which entering a basic block does not imply |
| 4223 | that all subsequent instructions must be executed. */ |
| 4224 | |
| 4225 | static int |
| 4226 | rtl_flow_call_edges_add (sbitmap blocks) |
| 4227 | { |
| 4228 | int i; |
| 4229 | int blocks_split = 0; |
| 4230 | int last_bb = last_basic_block; |
| 4231 | bool check_last_block = false; |
| 4232 | |
| 4233 | if (n_basic_blocks == NUM_FIXED_BLOCKS) |
| 4234 | return 0; |
| 4235 | |
| 4236 | if (! blocks) |
| 4237 | check_last_block = true; |
| 4238 | else |
| 4239 | check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index); |
| 4240 | |
| 4241 | /* In the last basic block, before epilogue generation, there will be |
| 4242 | a fallthru edge to EXIT. Special care is required if the last insn |
| 4243 | of the last basic block is a call because make_edge folds duplicate |
| 4244 | edges, which would result in the fallthru edge also being marked |
| 4245 | fake, which would result in the fallthru edge being removed by |
| 4246 | remove_fake_edges, which would result in an invalid CFG. |
| 4247 | |
| 4248 | Moreover, we can't elide the outgoing fake edge, since the block |
| 4249 | profiler needs to take this into account in order to solve the minimal |
| 4250 | spanning tree in the case that the call doesn't return. |
| 4251 | |
| 4252 | Handle this by adding a dummy instruction in a new last basic block. */ |
| 4253 | if (check_last_block) |
| 4254 | { |
| 4255 | basic_block bb = EXIT_BLOCK_PTR->prev_bb; |
| 4256 | rtx insn = BB_END (bb); |
| 4257 | |
| 4258 | /* Back up past insns that must be kept in the same block as a call. */ |
| 4259 | while (insn != BB_HEAD (bb) |
| 4260 | && keep_with_call_p (insn)) |
| 4261 | insn = PREV_INSN (insn); |
| 4262 | |
| 4263 | if (need_fake_edge_p (insn)) |
| 4264 | { |
| 4265 | edge e; |
| 4266 | |
| 4267 | e = find_edge (bb, EXIT_BLOCK_PTR); |
| 4268 | if (e) |
| 4269 | { |
| 4270 | insert_insn_on_edge (gen_use (const0_rtx), e); |
| 4271 | commit_edge_insertions (); |
| 4272 | } |
| 4273 | } |
| 4274 | } |
| 4275 | |
| 4276 | /* Now add fake edges to the function exit for any non constant |
| 4277 | calls since there is no way that we can determine if they will |
| 4278 | return or not... */ |
| 4279 | |
| 4280 | for (i = NUM_FIXED_BLOCKS; i < last_bb; i++) |
| 4281 | { |
| 4282 | basic_block bb = BASIC_BLOCK (i); |
| 4283 | rtx insn; |
| 4284 | rtx prev_insn; |
| 4285 | |
| 4286 | if (!bb) |
| 4287 | continue; |
| 4288 | |
| 4289 | if (blocks && !TEST_BIT (blocks, i)) |
| 4290 | continue; |
| 4291 | |
| 4292 | for (insn = BB_END (bb); ; insn = prev_insn) |
| 4293 | { |
| 4294 | prev_insn = PREV_INSN (insn); |
| 4295 | if (need_fake_edge_p (insn)) |
| 4296 | { |
| 4297 | edge e; |
| 4298 | rtx split_at_insn = insn; |
| 4299 | |
| 4300 | /* Don't split the block between a call and an insn that should |
| 4301 | remain in the same block as the call. */ |
| 4302 | if (CALL_P (insn)) |
| 4303 | while (split_at_insn != BB_END (bb) |
| 4304 | && keep_with_call_p (NEXT_INSN (split_at_insn))) |
| 4305 | split_at_insn = NEXT_INSN (split_at_insn); |
| 4306 | |
| 4307 | /* The handling above of the final block before the epilogue |
| 4308 | should be enough to verify that there is no edge to the exit |
| 4309 | block in CFG already. Calling make_edge in such case would |
| 4310 | cause us to mark that edge as fake and remove it later. */ |
| 4311 | |
| 4312 | #ifdef ENABLE_CHECKING |
| 4313 | if (split_at_insn == BB_END (bb)) |
| 4314 | { |
| 4315 | e = find_edge (bb, EXIT_BLOCK_PTR); |
| 4316 | gcc_assert (e == NULL); |
| 4317 | } |
| 4318 | #endif |
| 4319 | |
| 4320 | /* Note that the following may create a new basic block |
| 4321 | and renumber the existing basic blocks. */ |
| 4322 | if (split_at_insn != BB_END (bb)) |
| 4323 | { |
| 4324 | e = split_block (bb, split_at_insn); |
| 4325 | if (e) |
| 4326 | blocks_split++; |
| 4327 | } |
| 4328 | |
| 4329 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); |
| 4330 | } |
| 4331 | |
| 4332 | if (insn == BB_HEAD (bb)) |
| 4333 | break; |
| 4334 | } |
| 4335 | } |
| 4336 | |
| 4337 | if (blocks_split) |
| 4338 | verify_flow_info (); |
| 4339 | |
| 4340 | return blocks_split; |
| 4341 | } |
| 4342 | |
| 4343 | /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is |
| 4344 | the conditional branch target, SECOND_HEAD should be the fall-thru |
| 4345 | there is no need to handle this here the loop versioning code handles |
| 4346 | this. the reason for SECON_HEAD is that it is needed for condition |
| 4347 | in trees, and this should be of the same type since it is a hook. */ |
| 4348 | static void |
| 4349 | rtl_lv_add_condition_to_bb (basic_block first_head , |
| 4350 | basic_block second_head ATTRIBUTE_UNUSED, |
| 4351 | basic_block cond_bb, void *comp_rtx) |
| 4352 | { |
| 4353 | rtx label, seq, jump; |
| 4354 | rtx op0 = XEXP ((rtx)comp_rtx, 0); |
| 4355 | rtx op1 = XEXP ((rtx)comp_rtx, 1); |
| 4356 | enum rtx_code comp = GET_CODE ((rtx)comp_rtx); |
| 4357 | enum machine_mode mode; |
| 4358 | |
| 4359 | |
| 4360 | label = block_label (first_head); |
| 4361 | mode = GET_MODE (op0); |
| 4362 | if (mode == VOIDmode) |
| 4363 | mode = GET_MODE (op1); |
| 4364 | |
| 4365 | start_sequence (); |
| 4366 | op0 = force_operand (op0, NULL_RTX); |
| 4367 | op1 = force_operand (op1, NULL_RTX); |
| 4368 | do_compare_rtx_and_jump (op0, op1, comp, 0, |
| 4369 | mode, NULL_RTX, NULL_RTX, label, -1); |
| 4370 | jump = get_last_insn (); |
| 4371 | JUMP_LABEL (jump) = label; |
| 4372 | LABEL_NUSES (label)++; |
| 4373 | seq = get_insns (); |
| 4374 | end_sequence (); |
| 4375 | |
| 4376 | /* Add the new cond , in the new head. */ |
| 4377 | emit_insn_after(seq, BB_END(cond_bb)); |
| 4378 | } |
| 4379 | |
| 4380 | |
| 4381 | /* Given a block B with unconditional branch at its end, get the |
| 4382 | store the return the branch edge and the fall-thru edge in |
| 4383 | BRANCH_EDGE and FALLTHRU_EDGE respectively. */ |
| 4384 | static void |
| 4385 | rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge, |
| 4386 | edge *fallthru_edge) |
| 4387 | { |
| 4388 | edge e = EDGE_SUCC (b, 0); |
| 4389 | |
| 4390 | if (e->flags & EDGE_FALLTHRU) |
| 4391 | { |
| 4392 | *fallthru_edge = e; |
| 4393 | *branch_edge = EDGE_SUCC (b, 1); |
| 4394 | } |
| 4395 | else |
| 4396 | { |
| 4397 | *branch_edge = e; |
| 4398 | *fallthru_edge = EDGE_SUCC (b, 1); |
| 4399 | } |
| 4400 | } |
| 4401 | |
| 4402 | void |
| 4403 | init_rtl_bb_info (basic_block bb) |
| 4404 | { |
| 4405 | gcc_assert (!bb->il.x.rtl); |
| 4406 | bb->il.x.head_ = NULL; |
| 4407 | bb->il.x.rtl = ggc_alloc_cleared_rtl_bb_info (); |
| 4408 | } |
| 4409 | |
| 4410 | /* Returns true if it is possible to remove edge E by redirecting |
| 4411 | it to the destination of the other edge from E->src. */ |
| 4412 | |
| 4413 | static bool |
| 4414 | rtl_can_remove_branch_p (const_edge e) |
| 4415 | { |
| 4416 | const_basic_block src = e->src; |
| 4417 | const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest; |
| 4418 | const_rtx insn = BB_END (src), set; |
| 4419 | |
| 4420 | /* The conditions are taken from try_redirect_by_replacing_jump. */ |
| 4421 | if (target == EXIT_BLOCK_PTR) |
| 4422 | return false; |
| 4423 | |
| 4424 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
| 4425 | return false; |
| 4426 | |
| 4427 | if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) |
| 4428 | || BB_PARTITION (src) != BB_PARTITION (target)) |
| 4429 | return false; |
| 4430 | |
| 4431 | if (!onlyjump_p (insn) |
| 4432 | || tablejump_p (insn, NULL, NULL)) |
| 4433 | return false; |
| 4434 | |
| 4435 | set = single_set (insn); |
| 4436 | if (!set || side_effects_p (set)) |
| 4437 | return false; |
| 4438 | |
| 4439 | return true; |
| 4440 | } |
| 4441 | |
| 4442 | static basic_block |
| 4443 | rtl_duplicate_bb (basic_block bb) |
| 4444 | { |
| 4445 | bb = cfg_layout_duplicate_bb (bb); |
| 4446 | bb->aux = NULL; |
| 4447 | return bb; |
| 4448 | } |
| 4449 | |
| 4450 | /* Implementation of CFG manipulation for linearized RTL. */ |
| 4451 | struct cfg_hooks rtl_cfg_hooks = { |
| 4452 | "rtl", |
| 4453 | rtl_verify_flow_info, |
| 4454 | rtl_dump_bb, |
| 4455 | rtl_create_basic_block, |
| 4456 | rtl_redirect_edge_and_branch, |
| 4457 | rtl_redirect_edge_and_branch_force, |
| 4458 | rtl_can_remove_branch_p, |
| 4459 | rtl_delete_block, |
| 4460 | rtl_split_block, |
| 4461 | rtl_move_block_after, |
| 4462 | rtl_can_merge_blocks, /* can_merge_blocks_p */ |
| 4463 | rtl_merge_blocks, |
| 4464 | rtl_predict_edge, |
| 4465 | rtl_predicted_by_p, |
| 4466 | cfg_layout_can_duplicate_bb_p, |
| 4467 | rtl_duplicate_bb, |
| 4468 | rtl_split_edge, |
| 4469 | rtl_make_forwarder_block, |
| 4470 | rtl_tidy_fallthru_edge, |
| 4471 | rtl_force_nonfallthru, |
| 4472 | rtl_block_ends_with_call_p, |
| 4473 | rtl_block_ends_with_condjump_p, |
| 4474 | rtl_flow_call_edges_add, |
| 4475 | NULL, /* execute_on_growing_pred */ |
| 4476 | NULL, /* execute_on_shrinking_pred */ |
| 4477 | NULL, /* duplicate loop for trees */ |
| 4478 | NULL, /* lv_add_condition_to_bb */ |
| 4479 | NULL, /* lv_adjust_loop_header_phi*/ |
| 4480 | NULL, /* extract_cond_bb_edges */ |
| 4481 | NULL, /* flush_pending_stmts */ |
| 4482 | rtl_block_empty_p, /* block_empty_p */ |
| 4483 | rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */ |
| 4484 | }; |
| 4485 | |
| 4486 | /* Implementation of CFG manipulation for cfg layout RTL, where |
| 4487 | basic block connected via fallthru edges does not have to be adjacent. |
| 4488 | This representation will hopefully become the default one in future |
| 4489 | version of the compiler. */ |
| 4490 | |
| 4491 | struct cfg_hooks cfg_layout_rtl_cfg_hooks = { |
| 4492 | "cfglayout mode", |
| 4493 | rtl_verify_flow_info_1, |
| 4494 | rtl_dump_bb, |
| 4495 | cfg_layout_create_basic_block, |
| 4496 | cfg_layout_redirect_edge_and_branch, |
| 4497 | cfg_layout_redirect_edge_and_branch_force, |
| 4498 | rtl_can_remove_branch_p, |
| 4499 | cfg_layout_delete_block, |
| 4500 | cfg_layout_split_block, |
| 4501 | rtl_move_block_after, |
| 4502 | cfg_layout_can_merge_blocks_p, |
| 4503 | cfg_layout_merge_blocks, |
| 4504 | rtl_predict_edge, |
| 4505 | rtl_predicted_by_p, |
| 4506 | cfg_layout_can_duplicate_bb_p, |
| 4507 | cfg_layout_duplicate_bb, |
| 4508 | cfg_layout_split_edge, |
| 4509 | rtl_make_forwarder_block, |
| 4510 | NULL, /* tidy_fallthru_edge */ |
| 4511 | rtl_force_nonfallthru, |
| 4512 | rtl_block_ends_with_call_p, |
| 4513 | rtl_block_ends_with_condjump_p, |
| 4514 | rtl_flow_call_edges_add, |
| 4515 | NULL, /* execute_on_growing_pred */ |
| 4516 | NULL, /* execute_on_shrinking_pred */ |
| 4517 | duplicate_loop_to_header_edge, /* duplicate loop for trees */ |
| 4518 | rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */ |
| 4519 | NULL, /* lv_adjust_loop_header_phi*/ |
| 4520 | rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */ |
| 4521 | NULL, /* flush_pending_stmts */ |
| 4522 | rtl_block_empty_p, /* block_empty_p */ |
| 4523 | rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */ |
| 4524 | }; |
| 4525 | |
| 4526 | #include "gt-cfgrtl.h" |