1 | /* Control flow graph manipulation code for GNU compiler. |
2 | Copyright (C) 1987-2023 Free Software Foundation, Inc. |
3 | |
4 | This file is part of GCC. |
5 | |
6 | GCC is free software; you can redistribute it and/or modify it under |
7 | the terms of the GNU General Public License as published by the Free |
8 | Software Foundation; either version 3, or (at your option) any later |
9 | version. |
10 | |
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
14 | for more details. |
15 | |
16 | You should have received a copy of the GNU General Public License |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ |
19 | |
20 | /* This file contains low level functions to manipulate the CFG and analyze it |
21 | that are aware of the RTL intermediate language. |
22 | |
23 | Available functionality: |
24 | - Basic CFG/RTL manipulation API documented in cfghooks.h |
25 | - CFG-aware instruction chain manipulation |
26 | delete_insn, delete_insn_chain |
27 | - Edge splitting and committing to edges |
28 | insert_insn_on_edge, commit_edge_insertions |
29 | - CFG updating after insn simplification |
30 | purge_dead_edges, purge_all_dead_edges |
31 | - CFG fixing after coarse manipulation |
32 | fixup_abnormal_edges |
33 | |
34 | Functions not supposed for generic use: |
35 | - Infrastructure to determine quickly basic block for insn |
36 | compute_bb_for_insn, update_bb_for_insn, set_block_for_insn, |
37 | - Edge redirection with updating and optimizing of insn chain |
38 | block_label, tidy_fallthru_edge, force_nonfallthru */ |
39 | |
40 | #include "config.h" |
41 | #include "system.h" |
42 | #include "coretypes.h" |
43 | #include "backend.h" |
44 | #include "target.h" |
45 | #include "rtl.h" |
46 | #include "tree.h" |
47 | #include "cfghooks.h" |
48 | #include "df.h" |
49 | #include "insn-config.h" |
50 | #include "memmodel.h" |
51 | #include "emit-rtl.h" |
52 | #include "cfgrtl.h" |
53 | #include "cfganal.h" |
54 | #include "cfgbuild.h" |
55 | #include "cfgcleanup.h" |
56 | #include "bb-reorder.h" |
57 | #include "rtl-error.h" |
58 | #include "insn-attr.h" |
59 | #include "dojump.h" |
60 | #include "expr.h" |
61 | #include "cfgloop.h" |
62 | #include "tree-pass.h" |
63 | #include "print-rtl.h" |
64 | #include "rtl-iter.h" |
65 | #include "gimplify.h" |
66 | #include "profile.h" |
67 | #include "sreal.h" |
68 | |
69 | /* Disable warnings about missing quoting in GCC diagnostics. */ |
70 | #if __GNUC__ >= 10 |
71 | # pragma GCC diagnostic push |
72 | # pragma GCC diagnostic ignored "-Wformat-diag" |
73 | #endif |
74 | |
75 | /* Holds the interesting leading and trailing notes for the function. |
76 | Only applicable if the CFG is in cfglayout mode. */ |
77 | static GTY(()) rtx_insn *; |
78 | static GTY(()) rtx_insn *; |
79 | |
80 | static rtx_insn *skip_insns_after_block (basic_block); |
81 | static void record_effective_endpoints (void); |
82 | static void fixup_reorder_chain (void); |
83 | |
84 | void verify_insn_chain (void); |
85 | static void fixup_fallthru_exit_predecessor (void); |
86 | static bool can_delete_note_p (const rtx_note *); |
87 | static bool can_delete_label_p (const rtx_code_label *); |
88 | static basic_block rtl_split_edge (edge); |
89 | static bool rtl_move_block_after (basic_block, basic_block); |
90 | static bool rtl_verify_flow_info (void); |
91 | static basic_block cfg_layout_split_block (basic_block, void *); |
92 | static edge cfg_layout_redirect_edge_and_branch (edge, basic_block); |
93 | static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block); |
94 | static void cfg_layout_delete_block (basic_block); |
95 | static void rtl_delete_block (basic_block); |
96 | static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block); |
97 | static edge rtl_redirect_edge_and_branch (edge, basic_block); |
98 | static basic_block rtl_split_block (basic_block, void *); |
99 | static void rtl_dump_bb (FILE *, basic_block, int, dump_flags_t); |
100 | static bool rtl_verify_flow_info_1 (void); |
101 | static void rtl_make_forwarder_block (edge); |
102 | static bool rtl_bb_info_initialized_p (basic_block bb); |
103 | |
104 | /* Return true if NOTE is not one of the ones that must be kept paired, |
105 | so that we may simply delete it. */ |
106 | |
107 | static bool |
108 | can_delete_note_p (const rtx_note *note) |
109 | { |
110 | switch (NOTE_KIND (note)) |
111 | { |
112 | case NOTE_INSN_DELETED: |
113 | case NOTE_INSN_BASIC_BLOCK: |
114 | case NOTE_INSN_EPILOGUE_BEG: |
115 | return true; |
116 | |
117 | default: |
118 | return false; |
119 | } |
120 | } |
121 | |
122 | /* True if a given label can be deleted. */ |
123 | |
124 | static bool |
125 | can_delete_label_p (const rtx_code_label *label) |
126 | { |
127 | return (!LABEL_PRESERVE_P (label) |
128 | /* User declared labels must be preserved. */ |
129 | && LABEL_NAME (label) == 0 |
130 | && !vec_safe_contains<rtx_insn *> (forced_labels, |
131 | search: const_cast<rtx_code_label *> (label))); |
132 | } |
133 | |
134 | /* Delete INSN by patching it out. */ |
135 | |
136 | void |
137 | delete_insn (rtx_insn *insn) |
138 | { |
139 | rtx note; |
140 | bool really_delete = true; |
141 | |
142 | if (LABEL_P (insn)) |
143 | { |
144 | /* Some labels can't be directly removed from the INSN chain, as they |
145 | might be references via variables, constant pool etc. |
146 | Convert them to the special NOTE_INSN_DELETED_LABEL note. */ |
147 | if (! can_delete_label_p (label: as_a <rtx_code_label *> (p: insn))) |
148 | { |
149 | const char *name = LABEL_NAME (insn); |
150 | basic_block bb = BLOCK_FOR_INSN (insn); |
151 | rtx_insn *bb_note = NEXT_INSN (insn); |
152 | |
153 | really_delete = false; |
154 | PUT_CODE (insn, NOTE); |
155 | NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL; |
156 | NOTE_DELETED_LABEL_NAME (insn) = name; |
157 | |
158 | /* If the note following the label starts a basic block, and the |
159 | label is a member of the same basic block, interchange the two. */ |
160 | if (bb_note != NULL_RTX |
161 | && NOTE_INSN_BASIC_BLOCK_P (bb_note) |
162 | && bb != NULL |
163 | && bb == BLOCK_FOR_INSN (insn: bb_note)) |
164 | { |
165 | reorder_insns_nobb (insn, insn, bb_note); |
166 | BB_HEAD (bb) = bb_note; |
167 | if (BB_END (bb) == bb_note) |
168 | BB_END (bb) = insn; |
169 | } |
170 | } |
171 | |
172 | remove_node_from_insn_list (insn, &nonlocal_goto_handler_labels); |
173 | } |
174 | |
175 | if (really_delete) |
176 | { |
177 | /* If this insn has already been deleted, something is very wrong. */ |
178 | gcc_assert (!insn->deleted ()); |
179 | if (INSN_P (insn)) |
180 | df_insn_delete (insn); |
181 | remove_insn (insn); |
182 | insn->set_deleted (); |
183 | } |
184 | |
185 | /* If deleting a jump, decrement the use count of the label. Deleting |
186 | the label itself should happen in the normal course of block merging. */ |
187 | if (JUMP_P (insn)) |
188 | { |
189 | if (JUMP_LABEL (insn) |
190 | && LABEL_P (JUMP_LABEL (insn))) |
191 | LABEL_NUSES (JUMP_LABEL (insn))--; |
192 | |
193 | /* If there are more targets, remove them too. */ |
194 | while ((note |
195 | = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX |
196 | && LABEL_P (XEXP (note, 0))) |
197 | { |
198 | LABEL_NUSES (XEXP (note, 0))--; |
199 | remove_note (insn, note); |
200 | } |
201 | } |
202 | |
203 | /* Also if deleting any insn that references a label as an operand. */ |
204 | while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX |
205 | && LABEL_P (XEXP (note, 0))) |
206 | { |
207 | LABEL_NUSES (XEXP (note, 0))--; |
208 | remove_note (insn, note); |
209 | } |
210 | |
211 | if (rtx_jump_table_data *table = dyn_cast <rtx_jump_table_data *> (p: insn)) |
212 | { |
213 | rtvec vec = table->get_labels (); |
214 | int len = GET_NUM_ELEM (vec); |
215 | int i; |
216 | |
217 | for (i = 0; i < len; i++) |
218 | { |
219 | rtx label = XEXP (RTVEC_ELT (vec, i), 0); |
220 | |
221 | /* When deleting code in bulk (e.g. removing many unreachable |
222 | blocks) we can delete a label that's a target of the vector |
223 | before deleting the vector itself. */ |
224 | if (!NOTE_P (label)) |
225 | LABEL_NUSES (label)--; |
226 | } |
227 | } |
228 | } |
229 | |
230 | /* Like delete_insn but also purge dead edges from BB. |
231 | Return true if any edges are eliminated. */ |
232 | |
233 | bool |
234 | delete_insn_and_edges (rtx_insn *insn) |
235 | { |
236 | bool purge = false; |
237 | |
238 | if (NONDEBUG_INSN_P (insn) && BLOCK_FOR_INSN (insn)) |
239 | { |
240 | basic_block bb = BLOCK_FOR_INSN (insn); |
241 | if (BB_END (bb) == insn) |
242 | purge = true; |
243 | else if (DEBUG_INSN_P (BB_END (bb))) |
244 | for (rtx_insn *dinsn = NEXT_INSN (insn); |
245 | DEBUG_INSN_P (dinsn); dinsn = NEXT_INSN (insn: dinsn)) |
246 | if (BB_END (bb) == dinsn) |
247 | { |
248 | purge = true; |
249 | break; |
250 | } |
251 | } |
252 | delete_insn (insn); |
253 | if (purge) |
254 | return purge_dead_edges (BLOCK_FOR_INSN (insn)); |
255 | return false; |
256 | } |
257 | |
258 | /* Unlink a chain of insns between START and FINISH, leaving notes |
259 | that must be paired. If CLEAR_BB is true, we set bb field for |
260 | insns that cannot be removed to NULL. */ |
261 | |
262 | void |
263 | delete_insn_chain (rtx start, rtx_insn *finish, bool clear_bb) |
264 | { |
265 | /* Unchain the insns one by one. It would be quicker to delete all of these |
266 | with a single unchaining, rather than one at a time, but we need to keep |
267 | the NOTE's. */ |
268 | rtx_insn *current = finish; |
269 | while (1) |
270 | { |
271 | rtx_insn *prev = PREV_INSN (insn: current); |
272 | if (NOTE_P (current) && !can_delete_note_p (note: as_a <rtx_note *> (p: current))) |
273 | ; |
274 | else |
275 | delete_insn (insn: current); |
276 | |
277 | if (clear_bb && !current->deleted ()) |
278 | set_block_for_insn (insn: current, NULL); |
279 | |
280 | if (current == start) |
281 | break; |
282 | current = prev; |
283 | } |
284 | } |
285 | |
286 | /* Create a new basic block consisting of the instructions between HEAD and END |
287 | inclusive. This function is designed to allow fast BB construction - reuses |
288 | the note and basic block struct in BB_NOTE, if any and do not grow |
289 | BASIC_BLOCK chain and should be used directly only by CFG construction code. |
290 | END can be NULL in to create new empty basic block before HEAD. Both END |
291 | and HEAD can be NULL to create basic block at the end of INSN chain. |
292 | AFTER is the basic block we should be put after. */ |
293 | |
294 | basic_block |
295 | create_basic_block_structure (rtx_insn *head, rtx_insn *end, rtx_note *bb_note, |
296 | basic_block after) |
297 | { |
298 | basic_block bb; |
299 | |
300 | if (bb_note |
301 | && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL |
302 | && bb->aux == NULL) |
303 | { |
304 | /* If we found an existing note, thread it back onto the chain. */ |
305 | |
306 | rtx_insn *after; |
307 | |
308 | if (LABEL_P (head)) |
309 | after = head; |
310 | else |
311 | { |
312 | after = PREV_INSN (insn: head); |
313 | head = bb_note; |
314 | } |
315 | |
316 | if (after != bb_note && NEXT_INSN (insn: after) != bb_note) |
317 | reorder_insns_nobb (bb_note, bb_note, after); |
318 | } |
319 | else |
320 | { |
321 | /* Otherwise we must create a note and a basic block structure. */ |
322 | |
323 | bb = alloc_block (); |
324 | |
325 | init_rtl_bb_info (bb); |
326 | if (!head && !end) |
327 | head = end = bb_note |
328 | = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ()); |
329 | else if (LABEL_P (head) && end) |
330 | { |
331 | bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head); |
332 | if (head == end) |
333 | end = bb_note; |
334 | } |
335 | else |
336 | { |
337 | bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head); |
338 | head = bb_note; |
339 | if (!end) |
340 | end = head; |
341 | } |
342 | |
343 | NOTE_BASIC_BLOCK (bb_note) = bb; |
344 | } |
345 | |
346 | /* Always include the bb note in the block. */ |
347 | if (NEXT_INSN (insn: end) == bb_note) |
348 | end = bb_note; |
349 | |
350 | BB_HEAD (bb) = head; |
351 | BB_END (bb) = end; |
352 | bb->index = last_basic_block_for_fn (cfun)++; |
353 | bb->flags = BB_NEW | BB_RTL; |
354 | link_block (bb, after); |
355 | SET_BASIC_BLOCK_FOR_FN (cfun, bb->index, bb); |
356 | df_bb_refs_record (bb->index, false); |
357 | update_bb_for_insn (bb); |
358 | BB_SET_PARTITION (bb, BB_UNPARTITIONED); |
359 | |
360 | /* Tag the block so that we know it has been used when considering |
361 | other basic block notes. */ |
362 | bb->aux = bb; |
363 | |
364 | return bb; |
365 | } |
366 | |
367 | /* Create new basic block consisting of instructions in between HEAD and END |
368 | and place it to the BB chain after block AFTER. END can be NULL to |
369 | create a new empty basic block before HEAD. Both END and HEAD can be |
370 | NULL to create basic block at the end of INSN chain. */ |
371 | |
372 | static basic_block |
373 | rtl_create_basic_block (void *headp, void *endp, basic_block after) |
374 | { |
375 | rtx_insn *head = (rtx_insn *) headp; |
376 | rtx_insn *end = (rtx_insn *) endp; |
377 | basic_block bb; |
378 | |
379 | /* Grow the basic block array if needed. */ |
380 | if ((size_t) last_basic_block_for_fn (cfun) |
381 | >= basic_block_info_for_fn (cfun)->length ()) |
382 | vec_safe_grow_cleared (basic_block_info_for_fn (cfun), |
383 | last_basic_block_for_fn (cfun) + 1); |
384 | |
385 | n_basic_blocks_for_fn (cfun)++; |
386 | |
387 | bb = create_basic_block_structure (head, end, NULL, after); |
388 | bb->aux = NULL; |
389 | return bb; |
390 | } |
391 | |
392 | static basic_block |
393 | cfg_layout_create_basic_block (void *head, void *end, basic_block after) |
394 | { |
395 | basic_block newbb = rtl_create_basic_block (headp: head, endp: end, after); |
396 | |
397 | return newbb; |
398 | } |
399 | |
400 | /* Delete the insns in a (non-live) block. We physically delete every |
401 | non-deleted-note insn, and update the flow graph appropriately. |
402 | |
403 | Return nonzero if we deleted an exception handler. */ |
404 | |
405 | /* ??? Preserving all such notes strikes me as wrong. It would be nice |
406 | to post-process the stream to remove empty blocks, loops, ranges, etc. */ |
407 | |
408 | static void |
409 | rtl_delete_block (basic_block b) |
410 | { |
411 | rtx_insn *insn, *end; |
412 | |
413 | /* If the head of this block is a CODE_LABEL, then it might be the |
414 | label for an exception handler which can't be reached. We need |
415 | to remove the label from the exception_handler_label list. */ |
416 | insn = BB_HEAD (b); |
417 | |
418 | end = get_last_bb_insn (b); |
419 | |
420 | /* Selectively delete the entire chain. */ |
421 | BB_HEAD (b) = NULL; |
422 | delete_insn_chain (start: insn, finish: end, clear_bb: true); |
423 | |
424 | |
425 | if (dump_file) |
426 | fprintf (stream: dump_file, format: "deleting block %d\n" , b->index); |
427 | df_bb_delete (b->index); |
428 | } |
429 | |
430 | /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */ |
431 | |
432 | void |
433 | compute_bb_for_insn (void) |
434 | { |
435 | basic_block bb; |
436 | |
437 | FOR_EACH_BB_FN (bb, cfun) |
438 | { |
439 | rtx_insn *end = BB_END (bb); |
440 | rtx_insn *insn; |
441 | |
442 | for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn)) |
443 | { |
444 | BLOCK_FOR_INSN (insn) = bb; |
445 | if (insn == end) |
446 | break; |
447 | } |
448 | } |
449 | } |
450 | |
451 | /* Release the basic_block_for_insn array. */ |
452 | |
453 | void |
454 | free_bb_for_insn (void) |
455 | { |
456 | rtx_insn *insn; |
457 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
458 | if (!BARRIER_P (insn)) |
459 | BLOCK_FOR_INSN (insn) = NULL; |
460 | } |
461 | |
462 | namespace { |
463 | |
464 | const pass_data pass_data_free_cfg = |
465 | { |
466 | .type: RTL_PASS, /* type */ |
467 | .name: "*free_cfg" , /* name */ |
468 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
469 | .tv_id: TV_NONE, /* tv_id */ |
470 | .properties_required: 0, /* properties_required */ |
471 | .properties_provided: 0, /* properties_provided */ |
472 | PROP_cfg, /* properties_destroyed */ |
473 | .todo_flags_start: 0, /* todo_flags_start */ |
474 | .todo_flags_finish: 0, /* todo_flags_finish */ |
475 | }; |
476 | |
477 | class pass_free_cfg : public rtl_opt_pass |
478 | { |
479 | public: |
480 | pass_free_cfg (gcc::context *ctxt) |
481 | : rtl_opt_pass (pass_data_free_cfg, ctxt) |
482 | {} |
483 | |
484 | /* opt_pass methods: */ |
485 | unsigned int execute (function *) final override; |
486 | |
487 | }; // class pass_free_cfg |
488 | |
489 | unsigned int |
490 | pass_free_cfg::execute (function *) |
491 | { |
492 | /* The resource.cc machinery uses DF but the CFG isn't guaranteed to be |
493 | valid at that point so it would be too late to call df_analyze. */ |
494 | if (DELAY_SLOTS && optimize > 0 && flag_delayed_branch) |
495 | { |
496 | df_note_add_problem (); |
497 | df_analyze (); |
498 | } |
499 | |
500 | if (crtl->has_bb_partition) |
501 | insert_section_boundary_note (); |
502 | |
503 | free_bb_for_insn (); |
504 | return 0; |
505 | } |
506 | |
507 | } // anon namespace |
508 | |
509 | rtl_opt_pass * |
510 | make_pass_free_cfg (gcc::context *ctxt) |
511 | { |
512 | return new pass_free_cfg (ctxt); |
513 | } |
514 | |
515 | /* Return RTX to emit after when we want to emit code on the entry of function. */ |
516 | rtx_insn * |
517 | entry_of_function (void) |
518 | { |
519 | return (n_basic_blocks_for_fn (cfun) > NUM_FIXED_BLOCKS ? |
520 | BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb) : get_insns ()); |
521 | } |
522 | |
523 | /* Emit INSN at the entry point of the function, ensuring that it is only |
524 | executed once per function. */ |
525 | void |
526 | emit_insn_at_entry (rtx insn) |
527 | { |
528 | edge_iterator ei = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs); |
529 | edge e = ei_safe_edge (i: ei); |
530 | gcc_assert (e->flags & EDGE_FALLTHRU); |
531 | |
532 | insert_insn_on_edge (insn, e); |
533 | commit_edge_insertions (); |
534 | } |
535 | |
536 | /* Update BLOCK_FOR_INSN of insns between BEGIN and END |
537 | (or BARRIER if found) and notify df of the bb change. |
538 | The insn chain range is inclusive |
539 | (i.e. both BEGIN and END will be updated. */ |
540 | |
541 | static void |
542 | update_bb_for_insn_chain (rtx_insn *begin, rtx_insn *end, basic_block bb) |
543 | { |
544 | rtx_insn *insn; |
545 | |
546 | end = NEXT_INSN (insn: end); |
547 | for (insn = begin; insn != end; insn = NEXT_INSN (insn)) |
548 | if (!BARRIER_P (insn)) |
549 | df_insn_change_bb (insn, bb); |
550 | } |
551 | |
552 | /* Update BLOCK_FOR_INSN of insns in BB to BB, |
553 | and notify df of the change. */ |
554 | |
555 | void |
556 | update_bb_for_insn (basic_block bb) |
557 | { |
558 | update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb); |
559 | } |
560 | |
561 | |
562 | /* Like active_insn_p, except keep the return value use or clobber around |
563 | even after reload. */ |
564 | |
565 | static bool |
566 | flow_active_insn_p (const rtx_insn *insn) |
567 | { |
568 | if (active_insn_p (insn)) |
569 | return true; |
570 | |
571 | /* A clobber of the function return value exists for buggy |
572 | programs that fail to return a value. Its effect is to |
573 | keep the return value from being live across the entire |
574 | function. If we allow it to be skipped, we introduce the |
575 | possibility for register lifetime confusion. |
576 | Similarly, keep a USE of the function return value, otherwise |
577 | the USE is dropped and we could fail to thread jump if USE |
578 | appears on some paths and not on others, see PR90257. */ |
579 | if ((GET_CODE (PATTERN (insn)) == CLOBBER |
580 | || GET_CODE (PATTERN (insn)) == USE) |
581 | && REG_P (XEXP (PATTERN (insn), 0)) |
582 | && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0))) |
583 | return true; |
584 | |
585 | return false; |
586 | } |
587 | |
588 | /* Return true if the block has no effect and only forwards control flow to |
589 | its single destination. */ |
590 | |
591 | bool |
592 | contains_no_active_insn_p (const_basic_block bb) |
593 | { |
594 | rtx_insn *insn; |
595 | |
596 | if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun) |
597 | || bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
598 | || !single_succ_p (bb) |
599 | || (single_succ_edge (bb)->flags & EDGE_FAKE) != 0) |
600 | return false; |
601 | |
602 | for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn)) |
603 | if (INSN_P (insn) && flow_active_insn_p (insn)) |
604 | return false; |
605 | |
606 | return (!INSN_P (insn) |
607 | || (JUMP_P (insn) && simplejump_p (insn)) |
608 | || !flow_active_insn_p (insn)); |
609 | } |
610 | |
611 | /* Likewise, but protect loop latches, headers and preheaders. */ |
612 | /* FIXME: Make this a cfg hook. */ |
613 | |
614 | bool |
615 | forwarder_block_p (const_basic_block bb) |
616 | { |
617 | if (!contains_no_active_insn_p (bb)) |
618 | return false; |
619 | |
620 | /* Protect loop latches, headers and preheaders. */ |
621 | if (current_loops) |
622 | { |
623 | basic_block dest; |
624 | if (bb->loop_father->header == bb) |
625 | return false; |
626 | dest = EDGE_SUCC (bb, 0)->dest; |
627 | if (dest->loop_father->header == dest) |
628 | return false; |
629 | } |
630 | |
631 | return true; |
632 | } |
633 | |
634 | /* Return nonzero if we can reach target from src by falling through. */ |
635 | /* FIXME: Make this a cfg hook, the result is only valid in cfgrtl mode. */ |
636 | |
637 | bool |
638 | can_fallthru (basic_block src, basic_block target) |
639 | { |
640 | rtx_insn *insn = BB_END (src); |
641 | rtx_insn *insn2; |
642 | edge e; |
643 | edge_iterator ei; |
644 | |
645 | if (target == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
646 | return true; |
647 | if (src->next_bb != target) |
648 | return false; |
649 | |
650 | /* ??? Later we may add code to move jump tables offline. */ |
651 | if (tablejump_p (insn, NULL, NULL)) |
652 | return false; |
653 | |
654 | FOR_EACH_EDGE (e, ei, src->succs) |
655 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
656 | && e->flags & EDGE_FALLTHRU) |
657 | return false; |
658 | |
659 | insn2 = BB_HEAD (target); |
660 | if (!active_insn_p (insn2)) |
661 | insn2 = next_active_insn (insn2); |
662 | |
663 | return next_active_insn (insn) == insn2; |
664 | } |
665 | |
666 | /* Return nonzero if we could reach target from src by falling through, |
667 | if the target was made adjacent. If we already have a fall-through |
668 | edge to the exit block, we can't do that. */ |
669 | static bool |
670 | could_fall_through (basic_block src, basic_block target) |
671 | { |
672 | edge e; |
673 | edge_iterator ei; |
674 | |
675 | if (target == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
676 | return true; |
677 | FOR_EACH_EDGE (e, ei, src->succs) |
678 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
679 | && e->flags & EDGE_FALLTHRU) |
680 | return 0; |
681 | return true; |
682 | } |
683 | |
684 | /* Return the NOTE_INSN_BASIC_BLOCK of BB. */ |
685 | rtx_note * |
686 | bb_note (basic_block bb) |
687 | { |
688 | rtx_insn *note; |
689 | |
690 | note = BB_HEAD (bb); |
691 | if (LABEL_P (note)) |
692 | note = NEXT_INSN (insn: note); |
693 | |
694 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note)); |
695 | return as_a <rtx_note *> (p: note); |
696 | } |
697 | |
698 | /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK |
699 | note associated with the BLOCK. */ |
700 | |
701 | static rtx_insn * |
702 | first_insn_after_basic_block_note (basic_block block) |
703 | { |
704 | rtx_insn *insn; |
705 | |
706 | /* Get the first instruction in the block. */ |
707 | insn = BB_HEAD (block); |
708 | |
709 | if (insn == NULL_RTX) |
710 | return NULL; |
711 | if (LABEL_P (insn)) |
712 | insn = NEXT_INSN (insn); |
713 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn)); |
714 | |
715 | return NEXT_INSN (insn); |
716 | } |
717 | |
718 | /* Creates a new basic block just after basic block BB by splitting |
719 | everything after specified instruction INSNP. */ |
720 | |
721 | static basic_block |
722 | rtl_split_block (basic_block bb, void *insnp) |
723 | { |
724 | basic_block new_bb; |
725 | rtx_insn *insn = (rtx_insn *) insnp; |
726 | edge e; |
727 | edge_iterator ei; |
728 | |
729 | if (!insn) |
730 | { |
731 | insn = first_insn_after_basic_block_note (block: bb); |
732 | |
733 | if (insn) |
734 | { |
735 | rtx_insn *next = insn; |
736 | |
737 | insn = PREV_INSN (insn); |
738 | |
739 | /* If the block contains only debug insns, insn would have |
740 | been NULL in a non-debug compilation, and then we'd end |
741 | up emitting a DELETED note. For -fcompare-debug |
742 | stability, emit the note too. */ |
743 | if (insn != BB_END (bb) |
744 | && DEBUG_INSN_P (next) |
745 | && DEBUG_INSN_P (BB_END (bb))) |
746 | { |
747 | while (next != BB_END (bb) && DEBUG_INSN_P (next)) |
748 | next = NEXT_INSN (insn: next); |
749 | |
750 | if (next == BB_END (bb)) |
751 | emit_note_after (NOTE_INSN_DELETED, next); |
752 | } |
753 | } |
754 | else |
755 | insn = get_last_insn (); |
756 | } |
757 | |
758 | /* We probably should check type of the insn so that we do not create |
759 | inconsistent cfg. It is checked in verify_flow_info anyway, so do not |
760 | bother. */ |
761 | if (insn == BB_END (bb)) |
762 | emit_note_after (NOTE_INSN_DELETED, insn); |
763 | |
764 | /* Create the new basic block. */ |
765 | new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb); |
766 | BB_COPY_PARTITION (new_bb, bb); |
767 | BB_END (bb) = insn; |
768 | |
769 | /* Redirect the outgoing edges. */ |
770 | new_bb->succs = bb->succs; |
771 | bb->succs = NULL; |
772 | FOR_EACH_EDGE (e, ei, new_bb->succs) |
773 | e->src = new_bb; |
774 | |
775 | /* The new block starts off being dirty. */ |
776 | df_set_bb_dirty (bb); |
777 | return new_bb; |
778 | } |
779 | |
780 | /* Return true if LOC1 and LOC2 are equivalent for |
781 | unique_locus_on_edge_between_p purposes. */ |
782 | |
783 | static bool |
784 | loc_equal (location_t loc1, location_t loc2) |
785 | { |
786 | if (loc1 == loc2) |
787 | return true; |
788 | |
789 | expanded_location loce1 = expand_location (loc1); |
790 | expanded_location loce2 = expand_location (loc2); |
791 | |
792 | if (loce1.line != loce2.line |
793 | || loce1.column != loce2.column |
794 | || loce1.data != loce2.data) |
795 | return false; |
796 | if (loce1.file == loce2.file) |
797 | return true; |
798 | return (loce1.file != NULL |
799 | && loce2.file != NULL |
800 | && filename_cmp (s1: loce1.file, s2: loce2.file) == 0); |
801 | } |
802 | |
803 | /* Return true if the single edge between blocks A and B is the only place |
804 | in RTL which holds some unique locus. */ |
805 | |
806 | static bool |
807 | unique_locus_on_edge_between_p (basic_block a, basic_block b) |
808 | { |
809 | const location_t goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
810 | rtx_insn *insn, *end; |
811 | |
812 | if (LOCATION_LOCUS (goto_locus) == UNKNOWN_LOCATION) |
813 | return false; |
814 | |
815 | /* First scan block A backward. */ |
816 | insn = BB_END (a); |
817 | end = PREV_INSN (BB_HEAD (a)); |
818 | while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn))) |
819 | insn = PREV_INSN (insn); |
820 | |
821 | if (insn != end && loc_equal (loc1: INSN_LOCATION (insn), loc2: goto_locus)) |
822 | return false; |
823 | |
824 | /* Then scan block B forward. */ |
825 | insn = BB_HEAD (b); |
826 | if (insn) |
827 | { |
828 | end = NEXT_INSN (BB_END (b)); |
829 | while (insn != end && !NONDEBUG_INSN_P (insn)) |
830 | insn = NEXT_INSN (insn); |
831 | |
832 | if (insn != end && INSN_HAS_LOCATION (insn) |
833 | && loc_equal (loc1: INSN_LOCATION (insn), loc2: goto_locus)) |
834 | return false; |
835 | } |
836 | |
837 | return true; |
838 | } |
839 | |
840 | /* If the single edge between blocks A and B is the only place in RTL which |
841 | holds some unique locus, emit a nop with that locus between the blocks. */ |
842 | |
843 | static void |
844 | emit_nop_for_unique_locus_between (basic_block a, basic_block b) |
845 | { |
846 | if (!unique_locus_on_edge_between_p (a, b)) |
847 | return; |
848 | |
849 | BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a); |
850 | INSN_LOCATION (BB_END (a)) = EDGE_SUCC (a, 0)->goto_locus; |
851 | } |
852 | |
853 | /* Blocks A and B are to be merged into a single block A. The insns |
854 | are already contiguous. */ |
855 | |
856 | static void |
857 | rtl_merge_blocks (basic_block a, basic_block b) |
858 | { |
859 | /* If B is a forwarder block whose outgoing edge has no location, we'll |
860 | propagate the locus of the edge between A and B onto it. */ |
861 | const bool forward_edge_locus |
862 | = (b->flags & BB_FORWARDER_BLOCK) != 0 |
863 | && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION; |
864 | rtx_insn *b_head = BB_HEAD (b), *b_end = BB_END (b), *a_end = BB_END (a); |
865 | rtx_insn *del_first = NULL, *del_last = NULL; |
866 | rtx_insn *b_debug_start = b_end, *b_debug_end = b_end; |
867 | bool b_empty = false; |
868 | |
869 | if (dump_file) |
870 | fprintf (stream: dump_file, format: "Merging block %d into block %d...\n" , b->index, |
871 | a->index); |
872 | |
873 | while (DEBUG_INSN_P (b_end)) |
874 | b_end = PREV_INSN (insn: b_debug_start = b_end); |
875 | |
876 | /* If there was a CODE_LABEL beginning B, delete it. */ |
877 | if (LABEL_P (b_head)) |
878 | { |
879 | /* Detect basic blocks with nothing but a label. This can happen |
880 | in particular at the end of a function. */ |
881 | if (b_head == b_end) |
882 | b_empty = true; |
883 | |
884 | del_first = del_last = b_head; |
885 | b_head = NEXT_INSN (insn: b_head); |
886 | } |
887 | |
888 | /* Delete the basic block note and handle blocks containing just that |
889 | note. */ |
890 | if (NOTE_INSN_BASIC_BLOCK_P (b_head)) |
891 | { |
892 | if (b_head == b_end) |
893 | b_empty = true; |
894 | if (! del_last) |
895 | del_first = b_head; |
896 | |
897 | del_last = b_head; |
898 | b_head = NEXT_INSN (insn: b_head); |
899 | } |
900 | |
901 | /* If there was a jump out of A, delete it. */ |
902 | if (JUMP_P (a_end)) |
903 | { |
904 | rtx_insn *prev; |
905 | |
906 | for (prev = PREV_INSN (insn: a_end); ; prev = PREV_INSN (insn: prev)) |
907 | if (!NOTE_P (prev) |
908 | || NOTE_INSN_BASIC_BLOCK_P (prev) |
909 | || prev == BB_HEAD (a)) |
910 | break; |
911 | |
912 | del_first = a_end; |
913 | |
914 | a_end = PREV_INSN (insn: del_first); |
915 | } |
916 | else if (BARRIER_P (NEXT_INSN (a_end))) |
917 | del_first = NEXT_INSN (insn: a_end); |
918 | |
919 | /* Delete everything marked above as well as crap that might be |
920 | hanging out between the two blocks. */ |
921 | BB_END (a) = a_end; |
922 | BB_HEAD (b) = b_empty ? NULL : b_head; |
923 | delete_insn_chain (start: del_first, finish: del_last, clear_bb: true); |
924 | |
925 | /* If not optimizing, preserve the locus of the single edge between |
926 | blocks A and B if necessary by emitting a nop. */ |
927 | if (!optimize |
928 | && !forward_edge_locus |
929 | && !DECL_IGNORED_P (current_function_decl)) |
930 | { |
931 | emit_nop_for_unique_locus_between (a, b); |
932 | a_end = BB_END (a); |
933 | } |
934 | |
935 | /* Reassociate the insns of B with A. */ |
936 | if (!b_empty) |
937 | { |
938 | update_bb_for_insn_chain (begin: a_end, end: b_debug_end, bb: a); |
939 | |
940 | BB_END (a) = b_debug_end; |
941 | BB_HEAD (b) = NULL; |
942 | } |
943 | else if (b_end != b_debug_end) |
944 | { |
945 | /* Move any deleted labels and other notes between the end of A |
946 | and the debug insns that make up B after the debug insns, |
947 | bringing the debug insns into A while keeping the notes after |
948 | the end of A. */ |
949 | if (NEXT_INSN (insn: a_end) != b_debug_start) |
950 | reorder_insns_nobb (NEXT_INSN (insn: a_end), PREV_INSN (insn: b_debug_start), |
951 | b_debug_end); |
952 | update_bb_for_insn_chain (begin: b_debug_start, end: b_debug_end, bb: a); |
953 | BB_END (a) = b_debug_end; |
954 | } |
955 | |
956 | df_bb_delete (b->index); |
957 | |
958 | if (forward_edge_locus) |
959 | EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
960 | |
961 | if (dump_file) |
962 | fprintf (stream: dump_file, format: "Merged blocks %d and %d.\n" , a->index, b->index); |
963 | } |
964 | |
965 | |
966 | /* Return true when block A and B can be merged. */ |
967 | |
968 | static bool |
969 | rtl_can_merge_blocks (basic_block a, basic_block b) |
970 | { |
971 | /* If we are partitioning hot/cold basic blocks, we don't want to |
972 | mess up unconditional or indirect jumps that cross between hot |
973 | and cold sections. |
974 | |
975 | Basic block partitioning may result in some jumps that appear to |
976 | be optimizable (or blocks that appear to be mergeable), but which really |
977 | must be left untouched (they are required to make it safely across |
978 | partition boundaries). See the comments at the top of |
979 | bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */ |
980 | |
981 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
982 | return false; |
983 | |
984 | /* Protect the loop latches. */ |
985 | if (current_loops && b->loop_father->latch == b) |
986 | return false; |
987 | |
988 | /* There must be exactly one edge in between the blocks. */ |
989 | return (single_succ_p (bb: a) |
990 | && single_succ (bb: a) == b |
991 | && single_pred_p (bb: b) |
992 | && a != b |
993 | /* Must be simple edge. */ |
994 | && !(single_succ_edge (bb: a)->flags & EDGE_COMPLEX) |
995 | && a->next_bb == b |
996 | && a != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
997 | && b != EXIT_BLOCK_PTR_FOR_FN (cfun) |
998 | /* If the jump insn has side effects, |
999 | we can't kill the edge. */ |
1000 | && (!JUMP_P (BB_END (a)) |
1001 | || (reload_completed |
1002 | ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a))))); |
1003 | } |
1004 | |
1005 | /* Return the label in the head of basic block BLOCK. Create one if it doesn't |
1006 | exist. */ |
1007 | |
1008 | rtx_code_label * |
1009 | block_label (basic_block block) |
1010 | { |
1011 | if (block == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1012 | return NULL; |
1013 | |
1014 | if (!LABEL_P (BB_HEAD (block))) |
1015 | { |
1016 | BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block)); |
1017 | } |
1018 | |
1019 | return as_a <rtx_code_label *> (BB_HEAD (block)); |
1020 | } |
1021 | |
1022 | /* Remove all barriers from BB_FOOTER of a BB. */ |
1023 | |
1024 | static void |
1025 | (basic_block bb) |
1026 | { |
1027 | rtx_insn *insn = BB_FOOTER (bb); |
1028 | |
1029 | /* Remove barriers but keep jumptables. */ |
1030 | while (insn) |
1031 | { |
1032 | if (BARRIER_P (insn)) |
1033 | { |
1034 | if (PREV_INSN (insn)) |
1035 | SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); |
1036 | else |
1037 | BB_FOOTER (bb) = NEXT_INSN (insn); |
1038 | if (NEXT_INSN (insn)) |
1039 | SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); |
1040 | } |
1041 | if (LABEL_P (insn)) |
1042 | return; |
1043 | insn = NEXT_INSN (insn); |
1044 | } |
1045 | } |
1046 | |
1047 | /* Attempt to perform edge redirection by replacing possibly complex jump |
1048 | instruction by unconditional jump or removing jump completely. This can |
1049 | apply only if all edges now point to the same block. The parameters and |
1050 | return values are equivalent to redirect_edge_and_branch. */ |
1051 | |
1052 | edge |
1053 | try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout) |
1054 | { |
1055 | basic_block src = e->src; |
1056 | rtx_insn *insn = BB_END (src); |
1057 | rtx set; |
1058 | bool fallthru = false; |
1059 | |
1060 | /* If we are partitioning hot/cold basic blocks, we don't want to |
1061 | mess up unconditional or indirect jumps that cross between hot |
1062 | and cold sections. |
1063 | |
1064 | Basic block partitioning may result in some jumps that appear to |
1065 | be optimizable (or blocks that appear to be mergeable), but which really |
1066 | must be left untouched (they are required to make it safely across |
1067 | partition boundaries). See the comments at the top of |
1068 | bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */ |
1069 | |
1070 | if (BB_PARTITION (src) != BB_PARTITION (target)) |
1071 | return NULL; |
1072 | |
1073 | /* We can replace or remove a complex jump only when we have exactly |
1074 | two edges. Also, if we have exactly one outgoing edge, we can |
1075 | redirect that. */ |
1076 | if (EDGE_COUNT (src->succs) >= 3 |
1077 | /* Verify that all targets will be TARGET. Specifically, the |
1078 | edge that is not E must also go to TARGET. */ |
1079 | || (EDGE_COUNT (src->succs) == 2 |
1080 | && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)) |
1081 | return NULL; |
1082 | |
1083 | if (!onlyjump_p (insn)) |
1084 | return NULL; |
1085 | if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL)) |
1086 | return NULL; |
1087 | |
1088 | /* Avoid removing branch with side effects. */ |
1089 | set = single_set (insn); |
1090 | if (!set || side_effects_p (set)) |
1091 | return NULL; |
1092 | |
1093 | /* See if we can create the fallthru edge. */ |
1094 | if (in_cfglayout || can_fallthru (src, target)) |
1095 | { |
1096 | if (dump_file) |
1097 | fprintf (stream: dump_file, format: "Removing jump %i.\n" , INSN_UID (insn)); |
1098 | fallthru = true; |
1099 | |
1100 | /* Selectively unlink whole insn chain. */ |
1101 | if (in_cfglayout) |
1102 | { |
1103 | delete_insn_chain (start: insn, BB_END (src), clear_bb: false); |
1104 | remove_barriers_from_footer (bb: src); |
1105 | } |
1106 | else |
1107 | delete_insn_chain (start: insn, finish: PREV_INSN (BB_HEAD (target)), clear_bb: false); |
1108 | } |
1109 | |
1110 | /* If this already is simplejump, redirect it. */ |
1111 | else if (simplejump_p (insn)) |
1112 | { |
1113 | if (e->dest == target) |
1114 | return NULL; |
1115 | if (dump_file) |
1116 | fprintf (stream: dump_file, format: "Redirecting jump %i from %i to %i.\n" , |
1117 | INSN_UID (insn), e->dest->index, target->index); |
1118 | if (!redirect_jump (as_a <rtx_jump_insn *> (p: insn), |
1119 | block_label (block: target), 0)) |
1120 | { |
1121 | gcc_assert (target == EXIT_BLOCK_PTR_FOR_FN (cfun)); |
1122 | return NULL; |
1123 | } |
1124 | } |
1125 | |
1126 | /* Cannot do anything for target exit block. */ |
1127 | else if (target == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1128 | return NULL; |
1129 | |
1130 | /* Or replace possibly complicated jump insn by simple jump insn. */ |
1131 | else |
1132 | { |
1133 | rtx_code_label *target_label = block_label (block: target); |
1134 | rtx_insn *barrier; |
1135 | rtx_insn *label; |
1136 | rtx_jump_table_data *table; |
1137 | |
1138 | emit_jump_insn_after_noloc (targetm.gen_jump (target_label), insn); |
1139 | JUMP_LABEL (BB_END (src)) = target_label; |
1140 | LABEL_NUSES (target_label)++; |
1141 | if (dump_file) |
1142 | fprintf (stream: dump_file, format: "Replacing insn %i by jump %i\n" , |
1143 | INSN_UID (insn), INSN_UID (BB_END (src))); |
1144 | |
1145 | |
1146 | delete_insn_chain (start: insn, finish: insn, clear_bb: false); |
1147 | |
1148 | /* Recognize a tablejump that we are converting to a |
1149 | simple jump and remove its associated CODE_LABEL |
1150 | and ADDR_VEC or ADDR_DIFF_VEC. */ |
1151 | if (tablejump_p (insn, &label, &table)) |
1152 | delete_insn_chain (start: label, finish: table, clear_bb: false); |
1153 | |
1154 | barrier = next_nonnote_nondebug_insn (BB_END (src)); |
1155 | if (!barrier || !BARRIER_P (barrier)) |
1156 | emit_barrier_after (BB_END (src)); |
1157 | else |
1158 | { |
1159 | if (barrier != NEXT_INSN (BB_END (src))) |
1160 | { |
1161 | /* Move the jump before barrier so that the notes |
1162 | which originally were or were created before jump table are |
1163 | inside the basic block. */ |
1164 | rtx_insn *new_insn = BB_END (src); |
1165 | |
1166 | update_bb_for_insn_chain (begin: NEXT_INSN (BB_END (src)), |
1167 | end: PREV_INSN (insn: barrier), bb: src); |
1168 | |
1169 | SET_NEXT_INSN (PREV_INSN (insn: new_insn)) = NEXT_INSN (insn: new_insn); |
1170 | SET_PREV_INSN (NEXT_INSN (insn: new_insn)) = PREV_INSN (insn: new_insn); |
1171 | |
1172 | SET_NEXT_INSN (new_insn) = barrier; |
1173 | SET_NEXT_INSN (PREV_INSN (insn: barrier)) = new_insn; |
1174 | |
1175 | SET_PREV_INSN (new_insn) = PREV_INSN (insn: barrier); |
1176 | SET_PREV_INSN (barrier) = new_insn; |
1177 | } |
1178 | } |
1179 | } |
1180 | |
1181 | /* Keep only one edge out and set proper flags. */ |
1182 | if (!single_succ_p (bb: src)) |
1183 | remove_edge (e); |
1184 | gcc_assert (single_succ_p (src)); |
1185 | |
1186 | e = single_succ_edge (bb: src); |
1187 | if (fallthru) |
1188 | e->flags = EDGE_FALLTHRU; |
1189 | else |
1190 | e->flags = 0; |
1191 | |
1192 | e->probability = profile_probability::always (); |
1193 | |
1194 | if (e->dest != target) |
1195 | redirect_edge_succ (e, target); |
1196 | return e; |
1197 | } |
1198 | |
1199 | /* Subroutine of redirect_branch_edge that tries to patch the jump |
1200 | instruction INSN so that it reaches block NEW. Do this |
1201 | only when it originally reached block OLD. Return true if this |
1202 | worked or the original target wasn't OLD, return false if redirection |
1203 | doesn't work. */ |
1204 | |
1205 | static bool |
1206 | patch_jump_insn (rtx_insn *insn, rtx_insn *old_label, basic_block new_bb) |
1207 | { |
1208 | rtx_jump_table_data *table; |
1209 | rtx tmp; |
1210 | /* Recognize a tablejump and adjust all matching cases. */ |
1211 | if (tablejump_p (insn, NULL, &table)) |
1212 | { |
1213 | rtvec vec; |
1214 | int j; |
1215 | rtx_code_label *new_label = block_label (block: new_bb); |
1216 | |
1217 | if (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1218 | return false; |
1219 | vec = table->get_labels (); |
1220 | |
1221 | for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) |
1222 | if (XEXP (RTVEC_ELT (vec, j), 0) == old_label) |
1223 | { |
1224 | RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label); |
1225 | --LABEL_NUSES (old_label); |
1226 | ++LABEL_NUSES (new_label); |
1227 | } |
1228 | |
1229 | /* Handle casesi dispatch insns. */ |
1230 | if ((tmp = tablejump_casesi_pattern (insn)) != NULL_RTX |
1231 | && label_ref_label (XEXP (SET_SRC (tmp), 2)) == old_label) |
1232 | { |
1233 | XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode, |
1234 | new_label); |
1235 | --LABEL_NUSES (old_label); |
1236 | ++LABEL_NUSES (new_label); |
1237 | } |
1238 | } |
1239 | else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL) |
1240 | { |
1241 | int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp); |
1242 | rtx note; |
1243 | |
1244 | if (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1245 | return false; |
1246 | rtx_code_label *new_label = block_label (block: new_bb); |
1247 | |
1248 | for (i = 0; i < n; ++i) |
1249 | { |
1250 | rtx old_ref = ASM_OPERANDS_LABEL (tmp, i); |
1251 | gcc_assert (GET_CODE (old_ref) == LABEL_REF); |
1252 | if (XEXP (old_ref, 0) == old_label) |
1253 | { |
1254 | ASM_OPERANDS_LABEL (tmp, i) |
1255 | = gen_rtx_LABEL_REF (Pmode, new_label); |
1256 | --LABEL_NUSES (old_label); |
1257 | ++LABEL_NUSES (new_label); |
1258 | } |
1259 | } |
1260 | |
1261 | if (JUMP_LABEL (insn) == old_label) |
1262 | { |
1263 | JUMP_LABEL (insn) = new_label; |
1264 | note = find_reg_note (insn, REG_LABEL_TARGET, new_label); |
1265 | if (note) |
1266 | remove_note (insn, note); |
1267 | } |
1268 | else |
1269 | { |
1270 | note = find_reg_note (insn, REG_LABEL_TARGET, old_label); |
1271 | if (note) |
1272 | remove_note (insn, note); |
1273 | if (JUMP_LABEL (insn) != new_label |
1274 | && !find_reg_note (insn, REG_LABEL_TARGET, new_label)) |
1275 | add_reg_note (insn, REG_LABEL_TARGET, new_label); |
1276 | } |
1277 | while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label)) |
1278 | != NULL_RTX) |
1279 | XEXP (note, 0) = new_label; |
1280 | } |
1281 | else |
1282 | { |
1283 | /* ?? We may play the games with moving the named labels from |
1284 | one basic block to the other in case only one computed_jump is |
1285 | available. */ |
1286 | if (computed_jump_p (insn) |
1287 | /* A return instruction can't be redirected. */ |
1288 | || returnjump_p (insn)) |
1289 | return false; |
1290 | |
1291 | if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label) |
1292 | { |
1293 | /* If the insn doesn't go where we think, we're confused. */ |
1294 | gcc_assert (JUMP_LABEL (insn) == old_label); |
1295 | |
1296 | /* If the substitution doesn't succeed, die. This can happen |
1297 | if the back end emitted unrecognizable instructions or if |
1298 | target is exit block on some arches. Or for crossing |
1299 | jumps. */ |
1300 | if (!redirect_jump (as_a <rtx_jump_insn *> (p: insn), |
1301 | block_label (block: new_bb), 0)) |
1302 | { |
1303 | gcc_assert (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun) |
1304 | || CROSSING_JUMP_P (insn)); |
1305 | return false; |
1306 | } |
1307 | } |
1308 | } |
1309 | return true; |
1310 | } |
1311 | |
1312 | |
1313 | /* Redirect edge representing branch of (un)conditional jump or tablejump, |
1314 | NULL on failure */ |
1315 | static edge |
1316 | redirect_branch_edge (edge e, basic_block target) |
1317 | { |
1318 | rtx_insn *old_label = BB_HEAD (e->dest); |
1319 | basic_block src = e->src; |
1320 | rtx_insn *insn = BB_END (src); |
1321 | |
1322 | /* We can only redirect non-fallthru edges of jump insn. */ |
1323 | if (e->flags & EDGE_FALLTHRU) |
1324 | return NULL; |
1325 | else if (!JUMP_P (insn) && !currently_expanding_to_rtl) |
1326 | return NULL; |
1327 | |
1328 | if (!currently_expanding_to_rtl) |
1329 | { |
1330 | if (!patch_jump_insn (insn: as_a <rtx_jump_insn *> (p: insn), old_label, new_bb: target)) |
1331 | return NULL; |
1332 | } |
1333 | else |
1334 | /* When expanding this BB might actually contain multiple |
1335 | jumps (i.e. not yet split by find_many_sub_basic_blocks). |
1336 | Redirect all of those that match our label. */ |
1337 | FOR_BB_INSNS (src, insn) |
1338 | if (JUMP_P (insn) && !patch_jump_insn (insn: as_a <rtx_jump_insn *> (p: insn), |
1339 | old_label, new_bb: target)) |
1340 | return NULL; |
1341 | |
1342 | if (dump_file) |
1343 | fprintf (stream: dump_file, format: "Edge %i->%i redirected to %i\n" , |
1344 | e->src->index, e->dest->index, target->index); |
1345 | |
1346 | if (e->dest != target) |
1347 | e = redirect_edge_succ_nodup (e, target); |
1348 | |
1349 | return e; |
1350 | } |
1351 | |
1352 | /* Called when edge E has been redirected to a new destination, |
1353 | in order to update the region crossing flag on the edge and |
1354 | jump. */ |
1355 | |
1356 | static void |
1357 | fixup_partition_crossing (edge e) |
1358 | { |
1359 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) || e->dest |
1360 | == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1361 | return; |
1362 | /* If we redirected an existing edge, it may already be marked |
1363 | crossing, even though the new src is missing a reg crossing note. |
1364 | But make sure reg crossing note doesn't already exist before |
1365 | inserting. */ |
1366 | if (BB_PARTITION (e->src) != BB_PARTITION (e->dest)) |
1367 | { |
1368 | e->flags |= EDGE_CROSSING; |
1369 | if (JUMP_P (BB_END (e->src))) |
1370 | CROSSING_JUMP_P (BB_END (e->src)) = 1; |
1371 | } |
1372 | else if (BB_PARTITION (e->src) == BB_PARTITION (e->dest)) |
1373 | { |
1374 | e->flags &= ~EDGE_CROSSING; |
1375 | /* Remove the section crossing note from jump at end of |
1376 | src if it exists, and if no other successors are |
1377 | still crossing. */ |
1378 | if (JUMP_P (BB_END (e->src)) && CROSSING_JUMP_P (BB_END (e->src))) |
1379 | { |
1380 | bool has_crossing_succ = false; |
1381 | edge e2; |
1382 | edge_iterator ei; |
1383 | FOR_EACH_EDGE (e2, ei, e->src->succs) |
1384 | { |
1385 | has_crossing_succ |= (e2->flags & EDGE_CROSSING); |
1386 | if (has_crossing_succ) |
1387 | break; |
1388 | } |
1389 | if (!has_crossing_succ) |
1390 | CROSSING_JUMP_P (BB_END (e->src)) = 0; |
1391 | } |
1392 | } |
1393 | } |
1394 | |
1395 | /* Called when block BB has been reassigned to the cold partition, |
1396 | because it is now dominated by another cold block, |
1397 | to ensure that the region crossing attributes are updated. */ |
1398 | |
1399 | static void |
1400 | fixup_new_cold_bb (basic_block bb) |
1401 | { |
1402 | edge e; |
1403 | edge_iterator ei; |
1404 | |
1405 | /* This is called when a hot bb is found to now be dominated |
1406 | by a cold bb and therefore needs to become cold. Therefore, |
1407 | its preds will no longer be region crossing. Any non-dominating |
1408 | preds that were previously hot would also have become cold |
1409 | in the caller for the same region. Any preds that were previously |
1410 | region-crossing will be adjusted in fixup_partition_crossing. */ |
1411 | FOR_EACH_EDGE (e, ei, bb->preds) |
1412 | { |
1413 | fixup_partition_crossing (e); |
1414 | } |
1415 | |
1416 | /* Possibly need to make bb's successor edges region crossing, |
1417 | or remove stale region crossing. */ |
1418 | FOR_EACH_EDGE (e, ei, bb->succs) |
1419 | { |
1420 | /* We can't have fall-through edges across partition boundaries. |
1421 | Note that force_nonfallthru will do any necessary partition |
1422 | boundary fixup by calling fixup_partition_crossing itself. */ |
1423 | if ((e->flags & EDGE_FALLTHRU) |
1424 | && BB_PARTITION (bb) != BB_PARTITION (e->dest) |
1425 | && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1426 | force_nonfallthru (e); |
1427 | else |
1428 | fixup_partition_crossing (e); |
1429 | } |
1430 | } |
1431 | |
1432 | /* Attempt to change code to redirect edge E to TARGET. Don't do that on |
1433 | expense of adding new instructions or reordering basic blocks. |
1434 | |
1435 | Function can be also called with edge destination equivalent to the TARGET. |
1436 | Then it should try the simplifications and do nothing if none is possible. |
1437 | |
1438 | Return edge representing the branch if transformation succeeded. Return NULL |
1439 | on failure. |
1440 | We still return NULL in case E already destinated TARGET and we didn't |
1441 | managed to simplify instruction stream. */ |
1442 | |
1443 | static edge |
1444 | rtl_redirect_edge_and_branch (edge e, basic_block target) |
1445 | { |
1446 | edge ret; |
1447 | basic_block src = e->src; |
1448 | basic_block dest = e->dest; |
1449 | |
1450 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
1451 | return NULL; |
1452 | |
1453 | if (dest == target) |
1454 | return e; |
1455 | |
1456 | if ((ret = try_redirect_by_replacing_jump (e, target, in_cfglayout: false)) != NULL) |
1457 | { |
1458 | df_set_bb_dirty (src); |
1459 | fixup_partition_crossing (e: ret); |
1460 | return ret; |
1461 | } |
1462 | |
1463 | ret = redirect_branch_edge (e, target); |
1464 | if (!ret) |
1465 | return NULL; |
1466 | |
1467 | df_set_bb_dirty (src); |
1468 | fixup_partition_crossing (e: ret); |
1469 | return ret; |
1470 | } |
1471 | |
1472 | /* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */ |
1473 | |
1474 | void |
1475 | emit_barrier_after_bb (basic_block bb) |
1476 | { |
1477 | rtx_barrier *barrier = emit_barrier_after (BB_END (bb)); |
1478 | gcc_assert (current_ir_type () == IR_RTL_CFGRTL |
1479 | || current_ir_type () == IR_RTL_CFGLAYOUT); |
1480 | if (current_ir_type () == IR_RTL_CFGLAYOUT) |
1481 | { |
1482 | rtx_insn *insn = unlink_insn_chain (barrier, barrier); |
1483 | |
1484 | if (BB_FOOTER (bb)) |
1485 | { |
1486 | rtx_insn * = BB_FOOTER (bb); |
1487 | |
1488 | while (NEXT_INSN (insn: footer_tail)) |
1489 | footer_tail = NEXT_INSN (insn: footer_tail); |
1490 | if (!BARRIER_P (footer_tail)) |
1491 | { |
1492 | SET_NEXT_INSN (footer_tail) = insn; |
1493 | SET_PREV_INSN (insn) = footer_tail; |
1494 | } |
1495 | } |
1496 | else |
1497 | BB_FOOTER (bb) = insn; |
1498 | } |
1499 | } |
1500 | |
1501 | /* Like force_nonfallthru below, but additionally performs redirection |
1502 | Used by redirect_edge_and_branch_force. JUMP_LABEL is used only |
1503 | when redirecting to the EXIT_BLOCK, it is either ret_rtx or |
1504 | simple_return_rtx, indicating which kind of returnjump to create. |
1505 | It should be NULL otherwise. */ |
1506 | |
1507 | basic_block |
1508 | force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label) |
1509 | { |
1510 | basic_block jump_block, new_bb = NULL, src = e->src; |
1511 | rtx note; |
1512 | edge new_edge; |
1513 | int abnormal_edge_flags = 0; |
1514 | bool asm_goto_edge = false; |
1515 | int loc; |
1516 | |
1517 | /* In the case the last instruction is conditional jump to the next |
1518 | instruction, first redirect the jump itself and then continue |
1519 | by creating a basic block afterwards to redirect fallthru edge. */ |
1520 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
1521 | && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
1522 | && any_condjump_p (BB_END (e->src)) |
1523 | && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest)) |
1524 | { |
1525 | rtx note; |
1526 | edge b = unchecked_make_edge (e->src, target, 0); |
1527 | bool redirected; |
1528 | |
1529 | redirected = redirect_jump (as_a <rtx_jump_insn *> (BB_END (e->src)), |
1530 | block_label (block: target), 0); |
1531 | gcc_assert (redirected); |
1532 | |
1533 | note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX); |
1534 | if (note) |
1535 | { |
1536 | int prob = XINT (note, 0); |
1537 | |
1538 | b->probability = profile_probability::from_reg_br_prob_note (v: prob); |
1539 | e->probability -= e->probability; |
1540 | } |
1541 | } |
1542 | |
1543 | if (e->flags & EDGE_ABNORMAL) |
1544 | { |
1545 | /* Irritating special case - fallthru edge to the same block as abnormal |
1546 | edge. |
1547 | We can't redirect abnormal edge, but we still can split the fallthru |
1548 | one and create separate abnormal edge to original destination. |
1549 | This allows bb-reorder to make such edge non-fallthru. */ |
1550 | gcc_assert (e->dest == target); |
1551 | abnormal_edge_flags = e->flags & ~EDGE_FALLTHRU; |
1552 | e->flags &= EDGE_FALLTHRU; |
1553 | } |
1554 | else |
1555 | { |
1556 | gcc_assert (e->flags & EDGE_FALLTHRU); |
1557 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
1558 | { |
1559 | /* We can't redirect the entry block. Create an empty block |
1560 | at the start of the function which we use to add the new |
1561 | jump. */ |
1562 | edge tmp; |
1563 | edge_iterator ei; |
1564 | bool found = false; |
1565 | |
1566 | basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, |
1567 | ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
1568 | bb->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count; |
1569 | |
1570 | /* Make sure new block ends up in correct hot/cold section. */ |
1571 | BB_COPY_PARTITION (bb, e->dest); |
1572 | |
1573 | /* Change the existing edge's source to be the new block, and add |
1574 | a new edge from the entry block to the new block. */ |
1575 | e->src = bb; |
1576 | for (ei = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs); |
1577 | (tmp = ei_safe_edge (i: ei)); ) |
1578 | { |
1579 | if (tmp == e) |
1580 | { |
1581 | ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs->unordered_remove (ix: ei.index); |
1582 | found = true; |
1583 | break; |
1584 | } |
1585 | else |
1586 | ei_next (i: &ei); |
1587 | } |
1588 | |
1589 | gcc_assert (found); |
1590 | |
1591 | vec_safe_push (v&: bb->succs, obj: e); |
1592 | make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, |
1593 | EDGE_FALLTHRU); |
1594 | } |
1595 | } |
1596 | |
1597 | /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs |
1598 | don't point to the target or fallthru label. */ |
1599 | if (JUMP_P (BB_END (e->src)) |
1600 | && target != EXIT_BLOCK_PTR_FOR_FN (cfun) |
1601 | && (e->flags & EDGE_FALLTHRU) |
1602 | && (note = extract_asm_operands (PATTERN (BB_END (e->src))))) |
1603 | { |
1604 | int i, n = ASM_OPERANDS_LABEL_LENGTH (note); |
1605 | bool adjust_jump_target = false; |
1606 | |
1607 | for (i = 0; i < n; ++i) |
1608 | { |
1609 | if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (e->dest)) |
1610 | { |
1611 | LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note, i), 0))--; |
1612 | XEXP (ASM_OPERANDS_LABEL (note, i), 0) = block_label (block: target); |
1613 | LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note, i), 0))++; |
1614 | adjust_jump_target = true; |
1615 | } |
1616 | if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target)) |
1617 | asm_goto_edge = true; |
1618 | } |
1619 | if (adjust_jump_target) |
1620 | { |
1621 | rtx_insn *insn = BB_END (e->src); |
1622 | rtx note; |
1623 | rtx_insn *old_label = BB_HEAD (e->dest); |
1624 | rtx_insn *new_label = BB_HEAD (target); |
1625 | |
1626 | if (JUMP_LABEL (insn) == old_label) |
1627 | { |
1628 | JUMP_LABEL (insn) = new_label; |
1629 | note = find_reg_note (insn, REG_LABEL_TARGET, new_label); |
1630 | if (note) |
1631 | remove_note (insn, note); |
1632 | } |
1633 | else |
1634 | { |
1635 | note = find_reg_note (insn, REG_LABEL_TARGET, old_label); |
1636 | if (note) |
1637 | remove_note (insn, note); |
1638 | if (JUMP_LABEL (insn) != new_label |
1639 | && !find_reg_note (insn, REG_LABEL_TARGET, new_label)) |
1640 | add_reg_note (insn, REG_LABEL_TARGET, new_label); |
1641 | } |
1642 | while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label)) |
1643 | != NULL_RTX) |
1644 | XEXP (note, 0) = new_label; |
1645 | } |
1646 | } |
1647 | |
1648 | if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge) |
1649 | { |
1650 | rtx_insn *new_head; |
1651 | profile_count count = e->count (); |
1652 | profile_probability probability = e->probability; |
1653 | /* Create the new structures. */ |
1654 | |
1655 | /* If the old block ended with a tablejump, skip its table |
1656 | by searching forward from there. Otherwise start searching |
1657 | forward from the last instruction of the old block. */ |
1658 | rtx_jump_table_data *table; |
1659 | if (tablejump_p (BB_END (e->src), NULL, &table)) |
1660 | new_head = table; |
1661 | else |
1662 | new_head = BB_END (e->src); |
1663 | new_head = NEXT_INSN (insn: new_head); |
1664 | |
1665 | jump_block = create_basic_block (new_head, NULL, e->src); |
1666 | jump_block->count = count; |
1667 | |
1668 | /* Make sure new block ends up in correct hot/cold section. */ |
1669 | |
1670 | BB_COPY_PARTITION (jump_block, e->src); |
1671 | |
1672 | /* Wire edge in. */ |
1673 | new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU); |
1674 | new_edge->probability = probability; |
1675 | |
1676 | /* Redirect old edge. */ |
1677 | redirect_edge_pred (e, jump_block); |
1678 | e->probability = profile_probability::always (); |
1679 | |
1680 | /* If e->src was previously region crossing, it no longer is |
1681 | and the reg crossing note should be removed. */ |
1682 | fixup_partition_crossing (e: new_edge); |
1683 | |
1684 | /* If asm goto has any label refs to target's label, |
1685 | add also edge from asm goto bb to target. */ |
1686 | if (asm_goto_edge) |
1687 | { |
1688 | new_edge->probability /= 2; |
1689 | jump_block->count /= 2; |
1690 | edge new_edge2 = make_edge (new_edge->src, target, |
1691 | e->flags & ~EDGE_FALLTHRU); |
1692 | new_edge2->probability = probability - new_edge->probability; |
1693 | } |
1694 | |
1695 | new_bb = jump_block; |
1696 | } |
1697 | else |
1698 | jump_block = e->src; |
1699 | |
1700 | loc = e->goto_locus; |
1701 | e->flags &= ~EDGE_FALLTHRU; |
1702 | if (target == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1703 | { |
1704 | if (jump_label == ret_rtx) |
1705 | emit_jump_insn_after_setloc (targetm.gen_return (), |
1706 | BB_END (jump_block), loc); |
1707 | else |
1708 | { |
1709 | gcc_assert (jump_label == simple_return_rtx); |
1710 | emit_jump_insn_after_setloc (targetm.gen_simple_return (), |
1711 | BB_END (jump_block), loc); |
1712 | } |
1713 | set_return_jump_label (BB_END (jump_block)); |
1714 | } |
1715 | else |
1716 | { |
1717 | rtx_code_label *label = block_label (block: target); |
1718 | emit_jump_insn_after_setloc (targetm.gen_jump (label), |
1719 | BB_END (jump_block), loc); |
1720 | JUMP_LABEL (BB_END (jump_block)) = label; |
1721 | LABEL_NUSES (label)++; |
1722 | } |
1723 | |
1724 | /* We might be in cfg layout mode, and if so, the following routine will |
1725 | insert the barrier correctly. */ |
1726 | emit_barrier_after_bb (bb: jump_block); |
1727 | redirect_edge_succ_nodup (e, target); |
1728 | |
1729 | if (abnormal_edge_flags) |
1730 | make_edge (src, target, abnormal_edge_flags); |
1731 | |
1732 | df_mark_solutions_dirty (); |
1733 | fixup_partition_crossing (e); |
1734 | return new_bb; |
1735 | } |
1736 | |
1737 | /* Edge E is assumed to be fallthru edge. Emit needed jump instruction |
1738 | (and possibly create new basic block) to make edge non-fallthru. |
1739 | Return newly created BB or NULL if none. */ |
1740 | |
1741 | static basic_block |
1742 | rtl_force_nonfallthru (edge e) |
1743 | { |
1744 | return force_nonfallthru_and_redirect (e, target: e->dest, NULL_RTX); |
1745 | } |
1746 | |
1747 | /* Redirect edge even at the expense of creating new jump insn or |
1748 | basic block. Return new basic block if created, NULL otherwise. |
1749 | Conversion must be possible. */ |
1750 | |
1751 | static basic_block |
1752 | rtl_redirect_edge_and_branch_force (edge e, basic_block target) |
1753 | { |
1754 | if (redirect_edge_and_branch (e, target) |
1755 | || e->dest == target) |
1756 | return NULL; |
1757 | |
1758 | /* In case the edge redirection failed, try to force it to be non-fallthru |
1759 | and redirect newly created simplejump. */ |
1760 | df_set_bb_dirty (e->src); |
1761 | return force_nonfallthru_and_redirect (e, target, NULL_RTX); |
1762 | } |
1763 | |
1764 | /* The given edge should potentially be a fallthru edge. If that is in |
1765 | fact true, delete the jump and barriers that are in the way. */ |
1766 | |
1767 | static void |
1768 | rtl_tidy_fallthru_edge (edge e) |
1769 | { |
1770 | rtx_insn *q; |
1771 | basic_block b = e->src, c = b->next_bb; |
1772 | |
1773 | /* ??? In a late-running flow pass, other folks may have deleted basic |
1774 | blocks by nopping out blocks, leaving multiple BARRIERs between here |
1775 | and the target label. They ought to be chastised and fixed. |
1776 | |
1777 | We can also wind up with a sequence of undeletable labels between |
1778 | one block and the next. |
1779 | |
1780 | So search through a sequence of barriers, labels, and notes for |
1781 | the head of block C and assert that we really do fall through. */ |
1782 | |
1783 | for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (insn: q)) |
1784 | if (NONDEBUG_INSN_P (q)) |
1785 | return; |
1786 | |
1787 | /* Remove what will soon cease being the jump insn from the source block. |
1788 | If block B consisted only of this single jump, turn it into a deleted |
1789 | note. */ |
1790 | q = BB_END (b); |
1791 | if (JUMP_P (q) |
1792 | && onlyjump_p (q) |
1793 | && (any_uncondjump_p (q) |
1794 | || single_succ_p (bb: b))) |
1795 | { |
1796 | rtx_insn *label; |
1797 | rtx_jump_table_data *table; |
1798 | |
1799 | if (tablejump_p (q, &label, &table)) |
1800 | { |
1801 | /* The label is likely mentioned in some instruction before |
1802 | the tablejump and might not be DCEd, so turn it into |
1803 | a note instead and move before the tablejump that is going to |
1804 | be deleted. */ |
1805 | const char *name = LABEL_NAME (label); |
1806 | PUT_CODE (label, NOTE); |
1807 | NOTE_KIND (label) = NOTE_INSN_DELETED_LABEL; |
1808 | NOTE_DELETED_LABEL_NAME (label) = name; |
1809 | reorder_insns (label, label, PREV_INSN (insn: q)); |
1810 | delete_insn (insn: table); |
1811 | } |
1812 | |
1813 | q = PREV_INSN (insn: q); |
1814 | } |
1815 | /* Unconditional jumps with side-effects (i.e. which we can't just delete |
1816 | together with the barrier) should never have a fallthru edge. */ |
1817 | else if (JUMP_P (q) && any_uncondjump_p (q)) |
1818 | return; |
1819 | |
1820 | /* Selectively unlink the sequence. */ |
1821 | if (q != PREV_INSN (BB_HEAD (c))) |
1822 | delete_insn_chain (start: NEXT_INSN (insn: q), finish: PREV_INSN (BB_HEAD (c)), clear_bb: false); |
1823 | |
1824 | e->flags |= EDGE_FALLTHRU; |
1825 | } |
1826 | |
1827 | /* Should move basic block BB after basic block AFTER. NIY. */ |
1828 | |
1829 | static bool |
1830 | rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED, |
1831 | basic_block after ATTRIBUTE_UNUSED) |
1832 | { |
1833 | return false; |
1834 | } |
1835 | |
1836 | /* Locate the last bb in the same partition as START_BB. */ |
1837 | |
1838 | static basic_block |
1839 | last_bb_in_partition (basic_block start_bb) |
1840 | { |
1841 | basic_block bb; |
1842 | FOR_BB_BETWEEN (bb, start_bb, EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) |
1843 | { |
1844 | if (BB_PARTITION (start_bb) != BB_PARTITION (bb->next_bb)) |
1845 | return bb; |
1846 | } |
1847 | /* Return bb before the exit block. */ |
1848 | return bb->prev_bb; |
1849 | } |
1850 | |
1851 | /* Split a (typically critical) edge. Return the new block. |
1852 | The edge must not be abnormal. |
1853 | |
1854 | ??? The code generally expects to be called on critical edges. |
1855 | The case of a block ending in an unconditional jump to a |
1856 | block with multiple predecessors is not handled optimally. */ |
1857 | |
1858 | static basic_block |
1859 | rtl_split_edge (edge edge_in) |
1860 | { |
1861 | basic_block bb, new_bb; |
1862 | rtx_insn *before; |
1863 | |
1864 | /* Abnormal edges cannot be split. */ |
1865 | gcc_assert (!(edge_in->flags & EDGE_ABNORMAL)); |
1866 | |
1867 | /* We are going to place the new block in front of edge destination. |
1868 | Avoid existence of fallthru predecessors. */ |
1869 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
1870 | { |
1871 | edge e = find_fallthru_edge (edges: edge_in->dest->preds); |
1872 | |
1873 | if (e) |
1874 | force_nonfallthru (e); |
1875 | } |
1876 | |
1877 | /* Create the basic block note. */ |
1878 | if (edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1879 | before = BB_HEAD (edge_in->dest); |
1880 | else |
1881 | before = NULL; |
1882 | |
1883 | /* If this is a fall through edge to the exit block, the blocks might be |
1884 | not adjacent, and the right place is after the source. */ |
1885 | if ((edge_in->flags & EDGE_FALLTHRU) |
1886 | && edge_in->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1887 | { |
1888 | before = NEXT_INSN (BB_END (edge_in->src)); |
1889 | bb = create_basic_block (before, NULL, edge_in->src); |
1890 | BB_COPY_PARTITION (bb, edge_in->src); |
1891 | } |
1892 | else |
1893 | { |
1894 | if (edge_in->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
1895 | { |
1896 | bb = create_basic_block (before, NULL, edge_in->dest->prev_bb); |
1897 | BB_COPY_PARTITION (bb, edge_in->dest); |
1898 | } |
1899 | else |
1900 | { |
1901 | basic_block after = edge_in->dest->prev_bb; |
1902 | /* If this is post-bb reordering, and the edge crosses a partition |
1903 | boundary, the new block needs to be inserted in the bb chain |
1904 | at the end of the src partition (since we put the new bb into |
1905 | that partition, see below). Otherwise we may end up creating |
1906 | an extra partition crossing in the chain, which is illegal. |
1907 | It can't go after the src, because src may have a fall-through |
1908 | to a different block. */ |
1909 | if (crtl->bb_reorder_complete |
1910 | && (edge_in->flags & EDGE_CROSSING)) |
1911 | { |
1912 | after = last_bb_in_partition (start_bb: edge_in->src); |
1913 | before = get_last_bb_insn (after); |
1914 | /* The instruction following the last bb in partition should |
1915 | be a barrier, since it cannot end in a fall-through. */ |
1916 | gcc_checking_assert (BARRIER_P (before)); |
1917 | before = NEXT_INSN (insn: before); |
1918 | } |
1919 | bb = create_basic_block (before, NULL, after); |
1920 | /* Put the split bb into the src partition, to avoid creating |
1921 | a situation where a cold bb dominates a hot bb, in the case |
1922 | where src is cold and dest is hot. The src will dominate |
1923 | the new bb (whereas it might not have dominated dest). */ |
1924 | BB_COPY_PARTITION (bb, edge_in->src); |
1925 | } |
1926 | } |
1927 | |
1928 | make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU); |
1929 | |
1930 | /* Can't allow a region crossing edge to be fallthrough. */ |
1931 | if (BB_PARTITION (bb) != BB_PARTITION (edge_in->dest) |
1932 | && edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
1933 | { |
1934 | new_bb = force_nonfallthru (single_succ_edge (bb)); |
1935 | gcc_assert (!new_bb); |
1936 | } |
1937 | |
1938 | /* For non-fallthru edges, we must adjust the predecessor's |
1939 | jump instruction to target our new block. */ |
1940 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
1941 | { |
1942 | edge redirected = redirect_edge_and_branch (edge_in, bb); |
1943 | gcc_assert (redirected); |
1944 | } |
1945 | else |
1946 | { |
1947 | if (edge_in->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
1948 | { |
1949 | /* For asm goto even splitting of fallthru edge might |
1950 | need insn patching, as other labels might point to the |
1951 | old label. */ |
1952 | rtx_insn *last = BB_END (edge_in->src); |
1953 | if (last |
1954 | && JUMP_P (last) |
1955 | && edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
1956 | && (extract_asm_operands (PATTERN (insn: last)) |
1957 | || JUMP_LABEL (last) == before) |
1958 | && patch_jump_insn (insn: last, old_label: before, new_bb: bb)) |
1959 | df_set_bb_dirty (edge_in->src); |
1960 | } |
1961 | redirect_edge_succ (edge_in, bb); |
1962 | } |
1963 | |
1964 | return bb; |
1965 | } |
1966 | |
1967 | /* Queue instructions for insertion on an edge between two basic blocks. |
1968 | The new instructions and basic blocks (if any) will not appear in the |
1969 | CFG until commit_edge_insertions is called. */ |
1970 | |
1971 | void |
1972 | insert_insn_on_edge (rtx pattern, edge e) |
1973 | { |
1974 | /* We cannot insert instructions on an abnormal critical edge. |
1975 | It will be easier to find the culprit if we die now. */ |
1976 | gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e))); |
1977 | |
1978 | if (e->insns.r == NULL_RTX) |
1979 | start_sequence (); |
1980 | else |
1981 | push_to_sequence (e->insns.r); |
1982 | |
1983 | emit_insn (pattern); |
1984 | |
1985 | e->insns.r = get_insns (); |
1986 | end_sequence (); |
1987 | } |
1988 | |
1989 | /* Update the CFG for the instructions queued on edge E. */ |
1990 | |
1991 | void |
1992 | commit_one_edge_insertion (edge e) |
1993 | { |
1994 | rtx_insn *before = NULL, *after = NULL, *insns, *tmp, *last; |
1995 | basic_block bb; |
1996 | |
1997 | /* Pull the insns off the edge now since the edge might go away. */ |
1998 | insns = e->insns.r; |
1999 | e->insns.r = NULL; |
2000 | |
2001 | /* Figure out where to put these insns. If the destination has |
2002 | one predecessor, insert there. Except for the exit block. */ |
2003 | if (single_pred_p (bb: e->dest) && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
2004 | { |
2005 | bb = e->dest; |
2006 | |
2007 | /* Get the location correct wrt a code label, and "nice" wrt |
2008 | a basic block note, and before everything else. */ |
2009 | tmp = BB_HEAD (bb); |
2010 | if (LABEL_P (tmp)) |
2011 | tmp = NEXT_INSN (insn: tmp); |
2012 | if (NOTE_INSN_BASIC_BLOCK_P (tmp)) |
2013 | tmp = NEXT_INSN (insn: tmp); |
2014 | if (tmp == BB_HEAD (bb)) |
2015 | before = tmp; |
2016 | else if (tmp) |
2017 | after = PREV_INSN (insn: tmp); |
2018 | else |
2019 | after = get_last_insn (); |
2020 | } |
2021 | |
2022 | /* If the source has one successor and the edge is not abnormal, |
2023 | insert there. Except for the entry block. |
2024 | Don't do this if the predecessor ends in a jump other than |
2025 | unconditional simple jump. E.g. for asm goto that points all |
2026 | its labels at the fallthru basic block, we can't insert instructions |
2027 | before the asm goto, as the asm goto can have various of side effects, |
2028 | and can't emit instructions after the asm goto, as it must end |
2029 | the basic block. */ |
2030 | else if ((e->flags & EDGE_ABNORMAL) == 0 |
2031 | && single_succ_p (bb: e->src) |
2032 | && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
2033 | && (!JUMP_P (BB_END (e->src)) |
2034 | || simplejump_p (BB_END (e->src)))) |
2035 | { |
2036 | bb = e->src; |
2037 | |
2038 | /* It is possible to have a non-simple jump here. Consider a target |
2039 | where some forms of unconditional jumps clobber a register. This |
2040 | happens on the fr30 for example. |
2041 | |
2042 | We know this block has a single successor, so we can just emit |
2043 | the queued insns before the jump. */ |
2044 | if (JUMP_P (BB_END (bb))) |
2045 | before = BB_END (bb); |
2046 | else |
2047 | { |
2048 | /* We'd better be fallthru, or we've lost track of what's what. */ |
2049 | gcc_assert (e->flags & EDGE_FALLTHRU); |
2050 | |
2051 | after = BB_END (bb); |
2052 | } |
2053 | } |
2054 | |
2055 | /* Otherwise we must split the edge. */ |
2056 | else |
2057 | { |
2058 | bb = split_edge (e); |
2059 | |
2060 | /* If E crossed a partition boundary, we needed to make bb end in |
2061 | a region-crossing jump, even though it was originally fallthru. */ |
2062 | if (JUMP_P (BB_END (bb))) |
2063 | before = BB_END (bb); |
2064 | else |
2065 | after = BB_END (bb); |
2066 | } |
2067 | |
2068 | /* Now that we've found the spot, do the insertion. */ |
2069 | if (before) |
2070 | { |
2071 | emit_insn_before_noloc (insns, before, bb); |
2072 | last = prev_nonnote_insn (before); |
2073 | } |
2074 | else |
2075 | last = emit_insn_after_noloc (insns, after, bb); |
2076 | |
2077 | if (returnjump_p (last)) |
2078 | { |
2079 | /* ??? Remove all outgoing edges from BB and add one for EXIT. |
2080 | This is not currently a problem because this only happens |
2081 | for the (single) epilogue, which already has a fallthru edge |
2082 | to EXIT. */ |
2083 | |
2084 | e = single_succ_edge (bb); |
2085 | gcc_assert (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
2086 | && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU)); |
2087 | |
2088 | e->flags &= ~EDGE_FALLTHRU; |
2089 | emit_barrier_after (last); |
2090 | |
2091 | if (before) |
2092 | delete_insn (insn: before); |
2093 | } |
2094 | else |
2095 | gcc_assert (!JUMP_P (last)); |
2096 | } |
2097 | |
2098 | /* Update the CFG for all queued instructions. */ |
2099 | |
2100 | void |
2101 | commit_edge_insertions (void) |
2102 | { |
2103 | basic_block bb; |
2104 | |
2105 | /* Optimization passes that invoke this routine can cause hot blocks |
2106 | previously reached by both hot and cold blocks to become dominated only |
2107 | by cold blocks. This will cause the verification below to fail, |
2108 | and lead to now cold code in the hot section. In some cases this |
2109 | may only be visible after newly unreachable blocks are deleted, |
2110 | which will be done by fixup_partitions. */ |
2111 | fixup_partitions (); |
2112 | |
2113 | if (!currently_expanding_to_rtl) |
2114 | checking_verify_flow_info (); |
2115 | |
2116 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
2117 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) |
2118 | { |
2119 | edge e; |
2120 | edge_iterator ei; |
2121 | |
2122 | FOR_EACH_EDGE (e, ei, bb->succs) |
2123 | if (e->insns.r) |
2124 | { |
2125 | if (currently_expanding_to_rtl) |
2126 | rebuild_jump_labels_chain (e->insns.r); |
2127 | commit_one_edge_insertion (e); |
2128 | } |
2129 | } |
2130 | } |
2131 | |
2132 | |
2133 | /* Print out RTL-specific basic block information (live information |
2134 | at start and end with TDF_DETAILS). FLAGS are the TDF_* masks |
2135 | documented in dumpfile.h. */ |
2136 | |
2137 | static void |
2138 | rtl_dump_bb (FILE *outf, basic_block bb, int indent, dump_flags_t flags) |
2139 | { |
2140 | char *s_indent; |
2141 | |
2142 | s_indent = (char *) alloca ((size_t) indent + 1); |
2143 | memset (s: s_indent, c: ' ', n: (size_t) indent); |
2144 | s_indent[indent] = '\0'; |
2145 | |
2146 | if (df && (flags & TDF_DETAILS)) |
2147 | { |
2148 | df_dump_top (bb, outf); |
2149 | putc (c: '\n', stream: outf); |
2150 | } |
2151 | |
2152 | if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK |
2153 | && rtl_bb_info_initialized_p (bb)) |
2154 | { |
2155 | rtx_insn *last = BB_END (bb); |
2156 | if (last) |
2157 | last = NEXT_INSN (insn: last); |
2158 | for (rtx_insn *insn = BB_HEAD (bb); insn != last; insn = NEXT_INSN (insn)) |
2159 | { |
2160 | if (flags & TDF_DETAILS) |
2161 | df_dump_insn_top (insn, outf); |
2162 | if (! (flags & TDF_SLIM)) |
2163 | print_rtl_single (outf, insn); |
2164 | else |
2165 | dump_insn_slim (outf, insn); |
2166 | if (flags & TDF_DETAILS) |
2167 | df_dump_insn_bottom (insn, outf); |
2168 | } |
2169 | } |
2170 | |
2171 | if (df && (flags & TDF_DETAILS)) |
2172 | { |
2173 | df_dump_bottom (bb, outf); |
2174 | putc (c: '\n', stream: outf); |
2175 | } |
2176 | |
2177 | } |
2178 | |
2179 | /* Like dump_function_to_file, but for RTL. Print out dataflow information |
2180 | for the start of each basic block. FLAGS are the TDF_* masks documented |
2181 | in dumpfile.h. */ |
2182 | |
2183 | void |
2184 | print_rtl_with_bb (FILE *outf, const rtx_insn *rtx_first, dump_flags_t flags) |
2185 | { |
2186 | const rtx_insn *tmp_rtx; |
2187 | if (rtx_first == 0) |
2188 | fprintf (stream: outf, format: "(nil)\n" ); |
2189 | else |
2190 | { |
2191 | enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; |
2192 | int max_uid = get_max_uid (); |
2193 | basic_block *start = XCNEWVEC (basic_block, max_uid); |
2194 | basic_block *end = XCNEWVEC (basic_block, max_uid); |
2195 | enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid); |
2196 | basic_block bb; |
2197 | |
2198 | /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most |
2199 | insns, but the CFG is not maintained so the basic block info |
2200 | is not reliable. Therefore it's omitted from the dumps. */ |
2201 | if (! (cfun->curr_properties & PROP_cfg)) |
2202 | flags &= ~TDF_BLOCKS; |
2203 | |
2204 | if (df) |
2205 | df_dump_start (outf); |
2206 | |
2207 | if (cfun->curr_properties & PROP_cfg) |
2208 | { |
2209 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2210 | { |
2211 | rtx_insn *x; |
2212 | |
2213 | start[INSN_UID (BB_HEAD (bb))] = bb; |
2214 | end[INSN_UID (BB_END (bb))] = bb; |
2215 | if (flags & TDF_BLOCKS) |
2216 | { |
2217 | for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (insn: x)) |
2218 | { |
2219 | enum bb_state state = IN_MULTIPLE_BB; |
2220 | |
2221 | if (in_bb_p[INSN_UID (insn: x)] == NOT_IN_BB) |
2222 | state = IN_ONE_BB; |
2223 | in_bb_p[INSN_UID (insn: x)] = state; |
2224 | |
2225 | if (x == BB_END (bb)) |
2226 | break; |
2227 | } |
2228 | } |
2229 | } |
2230 | } |
2231 | |
2232 | for (tmp_rtx = rtx_first; tmp_rtx != NULL; tmp_rtx = NEXT_INSN (insn: tmp_rtx)) |
2233 | { |
2234 | if (flags & TDF_BLOCKS) |
2235 | { |
2236 | bb = start[INSN_UID (insn: tmp_rtx)]; |
2237 | if (bb != NULL) |
2238 | { |
2239 | dump_bb_info (outf, bb, 0, dump_flags, true, false); |
2240 | if (df && (flags & TDF_DETAILS)) |
2241 | df_dump_top (bb, outf); |
2242 | } |
2243 | |
2244 | if (in_bb_p[INSN_UID (insn: tmp_rtx)] == NOT_IN_BB |
2245 | && !NOTE_P (tmp_rtx) |
2246 | && !BARRIER_P (tmp_rtx)) |
2247 | fprintf (stream: outf, format: ";; Insn is not within a basic block\n" ); |
2248 | else if (in_bb_p[INSN_UID (insn: tmp_rtx)] == IN_MULTIPLE_BB) |
2249 | fprintf (stream: outf, format: ";; Insn is in multiple basic blocks\n" ); |
2250 | } |
2251 | |
2252 | if (flags & TDF_DETAILS) |
2253 | df_dump_insn_top (tmp_rtx, outf); |
2254 | if (! (flags & TDF_SLIM)) |
2255 | print_rtl_single (outf, tmp_rtx); |
2256 | else |
2257 | dump_insn_slim (outf, tmp_rtx); |
2258 | if (flags & TDF_DETAILS) |
2259 | df_dump_insn_bottom (tmp_rtx, outf); |
2260 | |
2261 | bb = end[INSN_UID (insn: tmp_rtx)]; |
2262 | if (bb != NULL) |
2263 | { |
2264 | if (flags & TDF_BLOCKS) |
2265 | { |
2266 | dump_bb_info (outf, bb, 0, dump_flags, false, true); |
2267 | if (df && (flags & TDF_DETAILS)) |
2268 | df_dump_bottom (bb, outf); |
2269 | putc (c: '\n', stream: outf); |
2270 | } |
2271 | /* Emit a hint if the fallthrough target of current basic block |
2272 | isn't the one placed right next. */ |
2273 | else if (EDGE_COUNT (bb->succs) > 0) |
2274 | { |
2275 | gcc_assert (BB_END (bb) == tmp_rtx); |
2276 | const rtx_insn *ninsn = NEXT_INSN (insn: tmp_rtx); |
2277 | /* Bypass intervening deleted-insn notes and debug insns. */ |
2278 | while (ninsn |
2279 | && !NONDEBUG_INSN_P (ninsn) |
2280 | && !start[INSN_UID (insn: ninsn)]) |
2281 | ninsn = NEXT_INSN (insn: ninsn); |
2282 | edge e = find_fallthru_edge (edges: bb->succs); |
2283 | if (e && ninsn) |
2284 | { |
2285 | basic_block dest = e->dest; |
2286 | if (start[INSN_UID (insn: ninsn)] != dest) |
2287 | fprintf (stream: outf, format: "%s ; pc falls through to BB %d\n" , |
2288 | print_rtx_head, dest->index); |
2289 | } |
2290 | } |
2291 | } |
2292 | } |
2293 | |
2294 | free (ptr: start); |
2295 | free (ptr: end); |
2296 | free (ptr: in_bb_p); |
2297 | } |
2298 | } |
2299 | |
2300 | /* Update the branch probability of BB if a REG_BR_PROB is present. */ |
2301 | |
2302 | void |
2303 | update_br_prob_note (basic_block bb) |
2304 | { |
2305 | rtx note; |
2306 | note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX); |
2307 | if (!JUMP_P (BB_END (bb)) || !BRANCH_EDGE (bb)->probability.initialized_p ()) |
2308 | { |
2309 | if (note) |
2310 | { |
2311 | rtx *note_link, this_rtx; |
2312 | |
2313 | note_link = ®_NOTES (BB_END (bb)); |
2314 | for (this_rtx = *note_link; this_rtx; this_rtx = XEXP (this_rtx, 1)) |
2315 | if (this_rtx == note) |
2316 | { |
2317 | *note_link = XEXP (this_rtx, 1); |
2318 | break; |
2319 | } |
2320 | } |
2321 | return; |
2322 | } |
2323 | if (!note |
2324 | || XINT (note, 0) == BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ()) |
2325 | return; |
2326 | XINT (note, 0) = BRANCH_EDGE (bb)->probability.to_reg_br_prob_note (); |
2327 | } |
2328 | |
2329 | /* Get the last insn associated with block BB (that includes barriers and |
2330 | tablejumps after BB). */ |
2331 | rtx_insn * |
2332 | get_last_bb_insn (basic_block bb) |
2333 | { |
2334 | rtx_jump_table_data *table; |
2335 | rtx_insn *tmp; |
2336 | rtx_insn *end = BB_END (bb); |
2337 | |
2338 | /* Include any jump table following the basic block. */ |
2339 | if (tablejump_p (end, NULL, &table)) |
2340 | end = table; |
2341 | |
2342 | /* Include any barriers that may follow the basic block. */ |
2343 | tmp = next_nonnote_nondebug_insn_bb (end); |
2344 | while (tmp && BARRIER_P (tmp)) |
2345 | { |
2346 | end = tmp; |
2347 | tmp = next_nonnote_nondebug_insn_bb (end); |
2348 | } |
2349 | |
2350 | return end; |
2351 | } |
2352 | |
2353 | /* Add all BBs reachable from entry via hot paths into the SET. */ |
2354 | |
2355 | void |
2356 | find_bbs_reachable_by_hot_paths (hash_set<basic_block> *set) |
2357 | { |
2358 | auto_vec<basic_block, 64> worklist; |
2359 | |
2360 | set->add (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
2361 | worklist.safe_push (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
2362 | |
2363 | while (worklist.length () > 0) |
2364 | { |
2365 | basic_block bb = worklist.pop (); |
2366 | edge_iterator ei; |
2367 | edge e; |
2368 | |
2369 | FOR_EACH_EDGE (e, ei, bb->succs) |
2370 | if (BB_PARTITION (e->dest) != BB_COLD_PARTITION |
2371 | && !set->add (k: e->dest)) |
2372 | worklist.safe_push (obj: e->dest); |
2373 | } |
2374 | } |
2375 | |
2376 | /* Sanity check partition hotness to ensure that basic blocks in |
2377 | Â the cold partition don't dominate basic blocks in the hot partition. |
2378 | If FLAG_ONLY is true, report violations as errors. Otherwise |
2379 | re-mark the dominated blocks as cold, since this is run after |
2380 | cfg optimizations that may make hot blocks previously reached |
2381 | by both hot and cold blocks now only reachable along cold paths. */ |
2382 | |
2383 | static auto_vec<basic_block> |
2384 | find_partition_fixes (bool flag_only) |
2385 | { |
2386 | basic_block bb; |
2387 | auto_vec<basic_block> bbs_to_fix; |
2388 | hash_set<basic_block> set; |
2389 | |
2390 | /* Callers check this. */ |
2391 | gcc_checking_assert (crtl->has_bb_partition); |
2392 | |
2393 | find_bbs_reachable_by_hot_paths (set: &set); |
2394 | |
2395 | FOR_EACH_BB_FN (bb, cfun) |
2396 | if (!set.contains (k: bb) |
2397 | && BB_PARTITION (bb) != BB_COLD_PARTITION) |
2398 | { |
2399 | if (flag_only) |
2400 | error ("non-cold basic block %d reachable only " |
2401 | "by paths crossing the cold partition" , bb->index); |
2402 | else |
2403 | BB_SET_PARTITION (bb, BB_COLD_PARTITION); |
2404 | bbs_to_fix.safe_push (obj: bb); |
2405 | } |
2406 | |
2407 | return bbs_to_fix; |
2408 | } |
2409 | |
2410 | /* Perform cleanup on the hot/cold bb partitioning after optimization |
2411 | passes that modify the cfg. */ |
2412 | |
2413 | void |
2414 | fixup_partitions (void) |
2415 | { |
2416 | if (!crtl->has_bb_partition) |
2417 | return; |
2418 | |
2419 | /* Delete any blocks that became unreachable and weren't |
2420 | already cleaned up, for example during edge forwarding |
2421 | and convert_jumps_to_returns. This will expose more |
2422 | opportunities for fixing the partition boundaries here. |
2423 | Also, the calculation of the dominance graph during verification |
2424 | will assert if there are unreachable nodes. */ |
2425 | delete_unreachable_blocks (); |
2426 | |
2427 | /* If there are partitions, do a sanity check on them: A basic block in |
2428 | Â a cold partition cannot dominate a basic block in a hot partition. |
2429 | Fixup any that now violate this requirement, as a result of edge |
2430 | forwarding and unreachable block deletion. Â */ |
2431 | auto_vec<basic_block> bbs_to_fix = find_partition_fixes (flag_only: false); |
2432 | |
2433 | /* Do the partition fixup after all necessary blocks have been converted to |
2434 | cold, so that we only update the region crossings the minimum number of |
2435 | places, which can require forcing edges to be non fallthru. */ |
2436 | if (! bbs_to_fix.is_empty ()) |
2437 | { |
2438 | do |
2439 | { |
2440 | basic_block bb = bbs_to_fix.pop (); |
2441 | fixup_new_cold_bb (bb); |
2442 | } |
2443 | while (! bbs_to_fix.is_empty ()); |
2444 | |
2445 | /* Fix up hot cold block grouping if needed. */ |
2446 | if (crtl->bb_reorder_complete && current_ir_type () == IR_RTL_CFGRTL) |
2447 | { |
2448 | basic_block bb, first = NULL, second = NULL; |
2449 | int current_partition = BB_UNPARTITIONED; |
2450 | |
2451 | FOR_EACH_BB_FN (bb, cfun) |
2452 | { |
2453 | if (current_partition != BB_UNPARTITIONED |
2454 | && BB_PARTITION (bb) != current_partition) |
2455 | { |
2456 | if (first == NULL) |
2457 | first = bb; |
2458 | else if (second == NULL) |
2459 | second = bb; |
2460 | else |
2461 | { |
2462 | /* If we switch partitions for the 3rd, 5th etc. time, |
2463 | move bbs first (inclusive) .. second (exclusive) right |
2464 | before bb. */ |
2465 | basic_block prev_first = first->prev_bb; |
2466 | basic_block prev_second = second->prev_bb; |
2467 | basic_block prev_bb = bb->prev_bb; |
2468 | prev_first->next_bb = second; |
2469 | second->prev_bb = prev_first; |
2470 | prev_second->next_bb = bb; |
2471 | bb->prev_bb = prev_second; |
2472 | prev_bb->next_bb = first; |
2473 | first->prev_bb = prev_bb; |
2474 | rtx_insn *prev_first_insn = PREV_INSN (BB_HEAD (first)); |
2475 | rtx_insn *prev_second_insn |
2476 | = PREV_INSN (BB_HEAD (second)); |
2477 | rtx_insn *prev_bb_insn = PREV_INSN (BB_HEAD (bb)); |
2478 | SET_NEXT_INSN (prev_first_insn) = BB_HEAD (second); |
2479 | SET_PREV_INSN (BB_HEAD (second)) = prev_first_insn; |
2480 | SET_NEXT_INSN (prev_second_insn) = BB_HEAD (bb); |
2481 | SET_PREV_INSN (BB_HEAD (bb)) = prev_second_insn; |
2482 | SET_NEXT_INSN (prev_bb_insn) = BB_HEAD (first); |
2483 | SET_PREV_INSN (BB_HEAD (first)) = prev_bb_insn; |
2484 | second = NULL; |
2485 | } |
2486 | } |
2487 | current_partition = BB_PARTITION (bb); |
2488 | } |
2489 | gcc_assert (!second); |
2490 | } |
2491 | } |
2492 | } |
2493 | |
2494 | /* Verify, in the basic block chain, that there is at most one switch |
2495 | between hot/cold partitions. This condition will not be true until |
2496 | after reorder_basic_blocks is called. */ |
2497 | |
2498 | static bool |
2499 | verify_hot_cold_block_grouping (void) |
2500 | { |
2501 | basic_block bb; |
2502 | bool err = false; |
2503 | bool switched_sections = false; |
2504 | int current_partition = BB_UNPARTITIONED; |
2505 | |
2506 | /* Even after bb reordering is complete, we go into cfglayout mode |
2507 | again (in compgoto). Ensure we don't call this before going back |
2508 | into linearized RTL when any layout fixes would have been committed. */ |
2509 | if (!crtl->bb_reorder_complete |
2510 | || current_ir_type () != IR_RTL_CFGRTL) |
2511 | return err; |
2512 | |
2513 | FOR_EACH_BB_FN (bb, cfun) |
2514 | { |
2515 | if (current_partition != BB_UNPARTITIONED |
2516 | && BB_PARTITION (bb) != current_partition) |
2517 | { |
2518 | if (switched_sections) |
2519 | { |
2520 | error ("multiple hot/cold transitions found (bb %i)" , |
2521 | bb->index); |
2522 | err = true; |
2523 | } |
2524 | else |
2525 | switched_sections = true; |
2526 | |
2527 | if (!crtl->has_bb_partition) |
2528 | error ("partition found but function partition flag not set" ); |
2529 | } |
2530 | current_partition = BB_PARTITION (bb); |
2531 | } |
2532 | |
2533 | return err; |
2534 | } |
2535 | |
2536 | |
2537 | /* Perform several checks on the edges out of each block, such as |
2538 | the consistency of the branch probabilities, the correctness |
2539 | of hot/cold partition crossing edges, and the number of expected |
2540 | successor edges. Also verify that the dominance relationship |
2541 | between hot/cold blocks is sane. */ |
2542 | |
2543 | static bool |
2544 | rtl_verify_edges (void) |
2545 | { |
2546 | bool err = false; |
2547 | basic_block bb; |
2548 | |
2549 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2550 | { |
2551 | int n_fallthru = 0, n_branch = 0, n_abnormal_call = 0, n_sibcall = 0; |
2552 | int n_eh = 0, n_abnormal = 0; |
2553 | edge e, fallthru = NULL; |
2554 | edge_iterator ei; |
2555 | rtx note; |
2556 | bool has_crossing_edge = false; |
2557 | |
2558 | if (JUMP_P (BB_END (bb)) |
2559 | && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX)) |
2560 | && EDGE_COUNT (bb->succs) >= 2 |
2561 | && any_condjump_p (BB_END (bb))) |
2562 | { |
2563 | if (!BRANCH_EDGE (bb)->probability.initialized_p ()) |
2564 | { |
2565 | if (profile_status_for_fn (cfun) != PROFILE_ABSENT) |
2566 | { |
2567 | error ("verify_flow_info: " |
2568 | "REG_BR_PROB is set but cfg probability is not" ); |
2569 | err = true; |
2570 | } |
2571 | } |
2572 | else if (XINT (note, 0) |
2573 | != BRANCH_EDGE (bb)->probability.to_reg_br_prob_note () |
2574 | && profile_status_for_fn (cfun) != PROFILE_ABSENT) |
2575 | { |
2576 | error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i" , |
2577 | XINT (note, 0), |
2578 | BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ()); |
2579 | err = true; |
2580 | } |
2581 | } |
2582 | |
2583 | FOR_EACH_EDGE (e, ei, bb->succs) |
2584 | { |
2585 | bool is_crossing; |
2586 | |
2587 | if (e->flags & EDGE_FALLTHRU) |
2588 | n_fallthru++, fallthru = e; |
2589 | |
2590 | is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest) |
2591 | && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
2592 | && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
2593 | has_crossing_edge |= is_crossing; |
2594 | if (e->flags & EDGE_CROSSING) |
2595 | { |
2596 | if (!is_crossing) |
2597 | { |
2598 | error ("EDGE_CROSSING incorrectly set across same section" ); |
2599 | err = true; |
2600 | } |
2601 | if (e->flags & EDGE_FALLTHRU) |
2602 | { |
2603 | error ("fallthru edge crosses section boundary in bb %i" , |
2604 | e->src->index); |
2605 | err = true; |
2606 | } |
2607 | if (e->flags & EDGE_EH) |
2608 | { |
2609 | error ("EH edge crosses section boundary in bb %i" , |
2610 | e->src->index); |
2611 | err = true; |
2612 | } |
2613 | if (JUMP_P (BB_END (bb)) && !CROSSING_JUMP_P (BB_END (bb))) |
2614 | { |
2615 | error ("No region crossing jump at section boundary in bb %i" , |
2616 | bb->index); |
2617 | err = true; |
2618 | } |
2619 | } |
2620 | else if (is_crossing) |
2621 | { |
2622 | error ("EDGE_CROSSING missing across section boundary" ); |
2623 | err = true; |
2624 | } |
2625 | |
2626 | if ((e->flags & ~(EDGE_DFS_BACK |
2627 | | EDGE_CAN_FALLTHRU |
2628 | | EDGE_IRREDUCIBLE_LOOP |
2629 | | EDGE_LOOP_EXIT |
2630 | | EDGE_CROSSING |
2631 | | EDGE_PRESERVE)) == 0) |
2632 | n_branch++; |
2633 | |
2634 | if (e->flags & EDGE_ABNORMAL_CALL) |
2635 | n_abnormal_call++; |
2636 | |
2637 | if (e->flags & EDGE_SIBCALL) |
2638 | n_sibcall++; |
2639 | |
2640 | if (e->flags & EDGE_EH) |
2641 | n_eh++; |
2642 | |
2643 | if (e->flags & EDGE_ABNORMAL) |
2644 | n_abnormal++; |
2645 | } |
2646 | |
2647 | if (!has_crossing_edge |
2648 | && JUMP_P (BB_END (bb)) |
2649 | && CROSSING_JUMP_P (BB_END (bb))) |
2650 | { |
2651 | print_rtl_with_bb (stderr, rtx_first: get_insns (), flags: TDF_BLOCKS | TDF_DETAILS); |
2652 | error ("Region crossing jump across same section in bb %i" , |
2653 | bb->index); |
2654 | err = true; |
2655 | } |
2656 | |
2657 | if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX)) |
2658 | { |
2659 | error ("missing REG_EH_REGION note at the end of bb %i" , bb->index); |
2660 | err = true; |
2661 | } |
2662 | if (n_eh > 1) |
2663 | { |
2664 | error ("too many exception handling edges in bb %i" , bb->index); |
2665 | err = true; |
2666 | } |
2667 | if (n_branch |
2668 | && (!JUMP_P (BB_END (bb)) |
2669 | || (n_branch > 1 && (any_uncondjump_p (BB_END (bb)) |
2670 | || any_condjump_p (BB_END (bb)))))) |
2671 | { |
2672 | error ("too many outgoing branch edges from bb %i" , bb->index); |
2673 | err = true; |
2674 | } |
2675 | if (n_fallthru && any_uncondjump_p (BB_END (bb))) |
2676 | { |
2677 | error ("fallthru edge after unconditional jump in bb %i" , bb->index); |
2678 | err = true; |
2679 | } |
2680 | if (n_branch != 1 && any_uncondjump_p (BB_END (bb))) |
2681 | { |
2682 | error ("wrong number of branch edges after unconditional jump" |
2683 | " in bb %i" , bb->index); |
2684 | err = true; |
2685 | } |
2686 | if (n_branch != 1 && any_condjump_p (BB_END (bb)) |
2687 | && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest)) |
2688 | { |
2689 | error ("wrong amount of branch edges after conditional jump" |
2690 | " in bb %i" , bb->index); |
2691 | err = true; |
2692 | } |
2693 | if (n_abnormal_call && !CALL_P (BB_END (bb))) |
2694 | { |
2695 | error ("abnormal call edges for non-call insn in bb %i" , bb->index); |
2696 | err = true; |
2697 | } |
2698 | if (n_sibcall && !CALL_P (BB_END (bb))) |
2699 | { |
2700 | error ("sibcall edges for non-call insn in bb %i" , bb->index); |
2701 | err = true; |
2702 | } |
2703 | if (n_abnormal > n_eh |
2704 | && !(CALL_P (BB_END (bb)) |
2705 | && n_abnormal == n_abnormal_call + n_sibcall) |
2706 | && (!JUMP_P (BB_END (bb)) |
2707 | || any_condjump_p (BB_END (bb)) |
2708 | || any_uncondjump_p (BB_END (bb)))) |
2709 | { |
2710 | error ("abnormal edges for no purpose in bb %i" , bb->index); |
2711 | err = true; |
2712 | } |
2713 | |
2714 | int has_eh = -1; |
2715 | FOR_EACH_EDGE (e, ei, bb->preds) |
2716 | { |
2717 | if (has_eh == -1) |
2718 | has_eh = (e->flags & EDGE_EH); |
2719 | if ((e->flags & EDGE_EH) == has_eh) |
2720 | continue; |
2721 | error ("EH incoming edge mixed with non-EH incoming edges " |
2722 | "in bb %i" , bb->index); |
2723 | err = true; |
2724 | break; |
2725 | } |
2726 | } |
2727 | |
2728 | /* If there are partitions, do a sanity check on them: A basic block in |
2729 | Â a cold partition cannot dominate a basic block in a hot partition. Â */ |
2730 | if (crtl->has_bb_partition && !err |
2731 | && current_ir_type () == IR_RTL_CFGLAYOUT) |
2732 | { |
2733 | auto_vec<basic_block> bbs_to_fix = find_partition_fixes (flag_only: true); |
2734 | err = !bbs_to_fix.is_empty (); |
2735 | } |
2736 | |
2737 | /* Clean up. */ |
2738 | return err; |
2739 | } |
2740 | |
2741 | /* Checks on the instructions within blocks. Currently checks that each |
2742 | block starts with a basic block note, and that basic block notes and |
2743 | control flow jumps are not found in the middle of the block. */ |
2744 | |
2745 | static bool |
2746 | rtl_verify_bb_insns (void) |
2747 | { |
2748 | rtx_insn *x; |
2749 | bool err = false; |
2750 | basic_block bb; |
2751 | |
2752 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2753 | { |
2754 | /* Now check the header of basic |
2755 | block. It ought to contain optional CODE_LABEL followed |
2756 | by NOTE_BASIC_BLOCK. */ |
2757 | x = BB_HEAD (bb); |
2758 | if (LABEL_P (x)) |
2759 | { |
2760 | if (BB_END (bb) == x) |
2761 | { |
2762 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d" , |
2763 | bb->index); |
2764 | err = true; |
2765 | } |
2766 | |
2767 | x = NEXT_INSN (insn: x); |
2768 | } |
2769 | |
2770 | if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb) |
2771 | { |
2772 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d" , |
2773 | bb->index); |
2774 | err = true; |
2775 | } |
2776 | |
2777 | if (BB_END (bb) == x) |
2778 | /* Do checks for empty blocks here. */ |
2779 | ; |
2780 | else |
2781 | for (x = NEXT_INSN (insn: x); x; x = NEXT_INSN (insn: x)) |
2782 | { |
2783 | if (NOTE_INSN_BASIC_BLOCK_P (x)) |
2784 | { |
2785 | error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d" , |
2786 | INSN_UID (insn: x), bb->index); |
2787 | err = true; |
2788 | } |
2789 | |
2790 | if (x == BB_END (bb)) |
2791 | break; |
2792 | |
2793 | if (control_flow_insn_p (x)) |
2794 | { |
2795 | error ("in basic block %d:" , bb->index); |
2796 | fatal_insn ("flow control insn inside a basic block" , x); |
2797 | } |
2798 | } |
2799 | } |
2800 | |
2801 | /* Clean up. */ |
2802 | return err; |
2803 | } |
2804 | |
2805 | /* Verify that block pointers for instructions in basic blocks, headers and |
2806 | footers are set appropriately. */ |
2807 | |
2808 | static bool |
2809 | rtl_verify_bb_pointers (void) |
2810 | { |
2811 | bool err = false; |
2812 | basic_block bb; |
2813 | |
2814 | /* Check the general integrity of the basic blocks. */ |
2815 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2816 | { |
2817 | rtx_insn *insn; |
2818 | |
2819 | if (!(bb->flags & BB_RTL)) |
2820 | { |
2821 | error ("BB_RTL flag not set for block %d" , bb->index); |
2822 | err = true; |
2823 | } |
2824 | |
2825 | FOR_BB_INSNS (bb, insn) |
2826 | if (BLOCK_FOR_INSN (insn) != bb) |
2827 | { |
2828 | error ("insn %d basic block pointer is %d, should be %d" , |
2829 | INSN_UID (insn), |
2830 | BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0, |
2831 | bb->index); |
2832 | err = true; |
2833 | } |
2834 | |
2835 | for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn)) |
2836 | if (!BARRIER_P (insn) |
2837 | && BLOCK_FOR_INSN (insn) != NULL) |
2838 | { |
2839 | error ("insn %d in header of bb %d has non-NULL basic block" , |
2840 | INSN_UID (insn), bb->index); |
2841 | err = true; |
2842 | } |
2843 | for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn)) |
2844 | if (!BARRIER_P (insn) |
2845 | && BLOCK_FOR_INSN (insn) != NULL) |
2846 | { |
2847 | error ("insn %d in footer of bb %d has non-NULL basic block" , |
2848 | INSN_UID (insn), bb->index); |
2849 | err = true; |
2850 | } |
2851 | } |
2852 | |
2853 | /* Clean up. */ |
2854 | return err; |
2855 | } |
2856 | |
2857 | /* Verify the CFG and RTL consistency common for both underlying RTL and |
2858 | cfglayout RTL. |
2859 | |
2860 | Currently it does following checks: |
2861 | |
2862 | - overlapping of basic blocks |
2863 | - insns with wrong BLOCK_FOR_INSN pointers |
2864 | - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note) |
2865 | - tails of basic blocks (ensure that boundary is necessary) |
2866 | - scans body of the basic block for JUMP_INSN, CODE_LABEL |
2867 | and NOTE_INSN_BASIC_BLOCK |
2868 | - verify that no fall_thru edge crosses hot/cold partition boundaries |
2869 | - verify that there are no pending RTL branch predictions |
2870 | - verify that hot blocks are not dominated by cold blocks |
2871 | |
2872 | In future it can be extended check a lot of other stuff as well |
2873 | (reachability of basic blocks, life information, etc. etc.). */ |
2874 | |
2875 | static bool |
2876 | rtl_verify_flow_info_1 (void) |
2877 | { |
2878 | bool err = false; |
2879 | |
2880 | if (rtl_verify_bb_pointers ()) |
2881 | err = true; |
2882 | |
2883 | if (rtl_verify_bb_insns ()) |
2884 | err = true; |
2885 | |
2886 | if (rtl_verify_edges ()) |
2887 | err = true; |
2888 | |
2889 | return err; |
2890 | } |
2891 | |
2892 | /* Walk the instruction chain and verify that bb head/end pointers |
2893 | are correct, and that instructions are in exactly one bb and have |
2894 | correct block pointers. */ |
2895 | |
2896 | static bool |
2897 | rtl_verify_bb_insn_chain (void) |
2898 | { |
2899 | basic_block bb; |
2900 | bool err = false; |
2901 | rtx_insn *x; |
2902 | rtx_insn *last_head = get_last_insn (); |
2903 | basic_block *bb_info; |
2904 | const int max_uid = get_max_uid (); |
2905 | |
2906 | bb_info = XCNEWVEC (basic_block, max_uid); |
2907 | |
2908 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2909 | { |
2910 | rtx_insn *head = BB_HEAD (bb); |
2911 | rtx_insn *end = BB_END (bb); |
2912 | |
2913 | for (x = last_head; x != NULL_RTX; x = PREV_INSN (insn: x)) |
2914 | { |
2915 | /* Verify the end of the basic block is in the INSN chain. */ |
2916 | if (x == end) |
2917 | break; |
2918 | |
2919 | /* And that the code outside of basic blocks has NULL bb field. */ |
2920 | if (!BARRIER_P (x) |
2921 | && BLOCK_FOR_INSN (insn: x) != NULL) |
2922 | { |
2923 | error ("insn %d outside of basic blocks has non-NULL bb field" , |
2924 | INSN_UID (insn: x)); |
2925 | err = true; |
2926 | } |
2927 | } |
2928 | |
2929 | if (!x) |
2930 | { |
2931 | error ("end insn %d for block %d not found in the insn stream" , |
2932 | INSN_UID (insn: end), bb->index); |
2933 | err = true; |
2934 | } |
2935 | |
2936 | /* Work backwards from the end to the head of the basic block |
2937 | to verify the head is in the RTL chain. */ |
2938 | for (; x != NULL_RTX; x = PREV_INSN (insn: x)) |
2939 | { |
2940 | /* While walking over the insn chain, verify insns appear |
2941 | in only one basic block. */ |
2942 | if (bb_info[INSN_UID (insn: x)] != NULL) |
2943 | { |
2944 | error ("insn %d is in multiple basic blocks (%d and %d)" , |
2945 | INSN_UID (insn: x), bb->index, bb_info[INSN_UID (insn: x)]->index); |
2946 | err = true; |
2947 | } |
2948 | |
2949 | bb_info[INSN_UID (insn: x)] = bb; |
2950 | |
2951 | if (x == head) |
2952 | break; |
2953 | } |
2954 | if (!x) |
2955 | { |
2956 | error ("head insn %d for block %d not found in the insn stream" , |
2957 | INSN_UID (insn: head), bb->index); |
2958 | err = true; |
2959 | } |
2960 | |
2961 | last_head = PREV_INSN (insn: x); |
2962 | } |
2963 | |
2964 | for (x = last_head; x != NULL_RTX; x = PREV_INSN (insn: x)) |
2965 | { |
2966 | /* Check that the code before the first basic block has NULL |
2967 | bb field. */ |
2968 | if (!BARRIER_P (x) |
2969 | && BLOCK_FOR_INSN (insn: x) != NULL) |
2970 | { |
2971 | error ("insn %d outside of basic blocks has non-NULL bb field" , |
2972 | INSN_UID (insn: x)); |
2973 | err = true; |
2974 | } |
2975 | } |
2976 | free (ptr: bb_info); |
2977 | |
2978 | return err; |
2979 | } |
2980 | |
2981 | /* Verify that fallthru edges point to adjacent blocks in layout order and |
2982 | that barriers exist after non-fallthru blocks. */ |
2983 | |
2984 | static bool |
2985 | rtl_verify_fallthru (void) |
2986 | { |
2987 | basic_block bb; |
2988 | bool err = false; |
2989 | |
2990 | FOR_EACH_BB_REVERSE_FN (bb, cfun) |
2991 | { |
2992 | edge e; |
2993 | |
2994 | e = find_fallthru_edge (edges: bb->succs); |
2995 | if (!e) |
2996 | { |
2997 | rtx_insn *insn; |
2998 | |
2999 | /* Ensure existence of barrier in BB with no fallthru edges. */ |
3000 | for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn)) |
3001 | { |
3002 | if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn)) |
3003 | { |
3004 | error ("missing barrier after block %i" , bb->index); |
3005 | err = true; |
3006 | break; |
3007 | } |
3008 | if (BARRIER_P (insn)) |
3009 | break; |
3010 | } |
3011 | } |
3012 | else if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
3013 | && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3014 | { |
3015 | rtx_insn *insn; |
3016 | |
3017 | if (e->src->next_bb != e->dest) |
3018 | { |
3019 | error |
3020 | ("verify_flow_info: Incorrect blocks for fallthru %i->%i" , |
3021 | e->src->index, e->dest->index); |
3022 | err = true; |
3023 | } |
3024 | else |
3025 | for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest); |
3026 | insn = NEXT_INSN (insn)) |
3027 | if (BARRIER_P (insn) || NONDEBUG_INSN_P (insn)) |
3028 | { |
3029 | error ("verify_flow_info: Incorrect fallthru %i->%i" , |
3030 | e->src->index, e->dest->index); |
3031 | error ("wrong insn in the fallthru edge" ); |
3032 | debug_rtx (insn); |
3033 | err = true; |
3034 | } |
3035 | } |
3036 | } |
3037 | |
3038 | return err; |
3039 | } |
3040 | |
3041 | /* Verify that blocks are laid out in consecutive order. While walking the |
3042 | instructions, verify that all expected instructions are inside the basic |
3043 | blocks, and that all returns are followed by barriers. */ |
3044 | |
3045 | static bool |
3046 | rtl_verify_bb_layout (void) |
3047 | { |
3048 | basic_block bb; |
3049 | bool err = false; |
3050 | rtx_insn *x, *y; |
3051 | int num_bb_notes; |
3052 | rtx_insn * const rtx_first = get_insns (); |
3053 | basic_block last_bb_seen = ENTRY_BLOCK_PTR_FOR_FN (cfun), curr_bb = NULL; |
3054 | |
3055 | num_bb_notes = 0; |
3056 | |
3057 | for (x = rtx_first; x; x = NEXT_INSN (insn: x)) |
3058 | { |
3059 | if (NOTE_INSN_BASIC_BLOCK_P (x)) |
3060 | { |
3061 | bb = NOTE_BASIC_BLOCK (x); |
3062 | |
3063 | num_bb_notes++; |
3064 | if (bb != last_bb_seen->next_bb) |
3065 | internal_error ("basic blocks not laid down consecutively" ); |
3066 | |
3067 | curr_bb = last_bb_seen = bb; |
3068 | } |
3069 | |
3070 | if (!curr_bb) |
3071 | { |
3072 | switch (GET_CODE (x)) |
3073 | { |
3074 | case BARRIER: |
3075 | case NOTE: |
3076 | break; |
3077 | |
3078 | case CODE_LABEL: |
3079 | /* An ADDR_VEC is placed outside any basic block. */ |
3080 | if (NEXT_INSN (insn: x) |
3081 | && JUMP_TABLE_DATA_P (NEXT_INSN (x))) |
3082 | x = NEXT_INSN (insn: x); |
3083 | |
3084 | /* But in any case, non-deletable labels can appear anywhere. */ |
3085 | break; |
3086 | |
3087 | default: |
3088 | fatal_insn ("insn outside basic block" , x); |
3089 | } |
3090 | } |
3091 | |
3092 | if (JUMP_P (x) |
3093 | && returnjump_p (x) && ! condjump_p (x) |
3094 | && ! ((y = next_nonnote_nondebug_insn (x)) |
3095 | && BARRIER_P (y))) |
3096 | fatal_insn ("return not followed by barrier" , x); |
3097 | |
3098 | if (curr_bb && x == BB_END (curr_bb)) |
3099 | curr_bb = NULL; |
3100 | } |
3101 | |
3102 | if (num_bb_notes != n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS) |
3103 | internal_error |
3104 | ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)" , |
3105 | num_bb_notes, n_basic_blocks_for_fn (cfun)); |
3106 | |
3107 | return err; |
3108 | } |
3109 | |
3110 | /* Verify the CFG and RTL consistency common for both underlying RTL and |
3111 | cfglayout RTL, plus consistency checks specific to linearized RTL mode. |
3112 | |
3113 | Currently it does following checks: |
3114 | - all checks of rtl_verify_flow_info_1 |
3115 | - test head/end pointers |
3116 | - check that blocks are laid out in consecutive order |
3117 | - check that all insns are in the basic blocks |
3118 | (except the switch handling code, barriers and notes) |
3119 | - check that all returns are followed by barriers |
3120 | - check that all fallthru edge points to the adjacent blocks |
3121 | - verify that there is a single hot/cold partition boundary after bbro */ |
3122 | |
3123 | static bool |
3124 | rtl_verify_flow_info (void) |
3125 | { |
3126 | bool err = false; |
3127 | |
3128 | if (rtl_verify_flow_info_1 ()) |
3129 | err = true; |
3130 | |
3131 | if (rtl_verify_bb_insn_chain ()) |
3132 | err = true; |
3133 | |
3134 | if (rtl_verify_fallthru ()) |
3135 | err = true; |
3136 | |
3137 | if (rtl_verify_bb_layout ()) |
3138 | err = true; |
3139 | |
3140 | if (verify_hot_cold_block_grouping ()) |
3141 | err = true; |
3142 | |
3143 | return err; |
3144 | } |
3145 | |
3146 | /* Assume that the preceding pass has possibly eliminated jump instructions |
3147 | or converted the unconditional jumps. Eliminate the edges from CFG. |
3148 | Return true if any edges are eliminated. */ |
3149 | |
3150 | bool |
3151 | purge_dead_edges (basic_block bb) |
3152 | { |
3153 | edge e; |
3154 | rtx_insn *insn = BB_END (bb); |
3155 | rtx note; |
3156 | bool purged = false; |
3157 | bool found; |
3158 | edge_iterator ei; |
3159 | |
3160 | if ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb)) |
3161 | do |
3162 | insn = PREV_INSN (insn); |
3163 | while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb)); |
3164 | |
3165 | /* If this instruction cannot trap, remove REG_EH_REGION notes. */ |
3166 | if (NONJUMP_INSN_P (insn) |
3167 | && (note = find_reg_note (insn, REG_EH_REGION, NULL))) |
3168 | { |
3169 | rtx eqnote; |
3170 | |
3171 | if (! may_trap_p (PATTERN (insn)) |
3172 | || ((eqnote = find_reg_equal_equiv_note (insn)) |
3173 | && ! may_trap_p (XEXP (eqnote, 0)))) |
3174 | remove_note (insn, note); |
3175 | } |
3176 | |
3177 | /* Cleanup abnormal edges caused by exceptions or non-local gotos. */ |
3178 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (i: ei)); ) |
3179 | { |
3180 | bool remove = false; |
3181 | |
3182 | /* There are three types of edges we need to handle correctly here: EH |
3183 | edges, abnormal call EH edges, and abnormal call non-EH edges. The |
3184 | latter can appear when nonlocal gotos are used. */ |
3185 | if (e->flags & EDGE_ABNORMAL_CALL) |
3186 | { |
3187 | if (!CALL_P (insn)) |
3188 | remove = true; |
3189 | else if (can_nonlocal_goto (insn)) |
3190 | ; |
3191 | else if ((e->flags & EDGE_EH) && can_throw_internal (insn)) |
3192 | ; |
3193 | else if (flag_tm && find_reg_note (insn, REG_TM, NULL)) |
3194 | ; |
3195 | else |
3196 | remove = true; |
3197 | } |
3198 | else if (e->flags & EDGE_EH) |
3199 | remove = !can_throw_internal (insn); |
3200 | |
3201 | if (remove) |
3202 | { |
3203 | remove_edge (e); |
3204 | df_set_bb_dirty (bb); |
3205 | purged = true; |
3206 | } |
3207 | else |
3208 | ei_next (i: &ei); |
3209 | } |
3210 | |
3211 | if (JUMP_P (insn)) |
3212 | { |
3213 | rtx note; |
3214 | edge b,f; |
3215 | edge_iterator ei; |
3216 | |
3217 | /* We do care only about conditional jumps and simplejumps. */ |
3218 | if (!any_condjump_p (insn) |
3219 | && !returnjump_p (insn) |
3220 | && !simplejump_p (insn)) |
3221 | return purged; |
3222 | |
3223 | /* Branch probability/prediction notes are defined only for |
3224 | condjumps. We've possibly turned condjump into simplejump. */ |
3225 | if (simplejump_p (insn)) |
3226 | { |
3227 | note = find_reg_note (insn, REG_BR_PROB, NULL); |
3228 | if (note) |
3229 | remove_note (insn, note); |
3230 | while ((note = find_reg_note (insn, REG_BR_PRED, NULL))) |
3231 | remove_note (insn, note); |
3232 | } |
3233 | |
3234 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (i: ei)); ) |
3235 | { |
3236 | /* Avoid abnormal flags to leak from computed jumps turned |
3237 | into simplejumps. */ |
3238 | |
3239 | e->flags &= ~EDGE_ABNORMAL; |
3240 | |
3241 | /* See if this edge is one we should keep. */ |
3242 | if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn)) |
3243 | /* A conditional jump can fall through into the next |
3244 | block, so we should keep the edge. */ |
3245 | { |
3246 | ei_next (i: &ei); |
3247 | continue; |
3248 | } |
3249 | else if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
3250 | && BB_HEAD (e->dest) == JUMP_LABEL (insn)) |
3251 | /* If the destination block is the target of the jump, |
3252 | keep the edge. */ |
3253 | { |
3254 | ei_next (i: &ei); |
3255 | continue; |
3256 | } |
3257 | else if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
3258 | && returnjump_p (insn)) |
3259 | /* If the destination block is the exit block, and this |
3260 | instruction is a return, then keep the edge. */ |
3261 | { |
3262 | ei_next (i: &ei); |
3263 | continue; |
3264 | } |
3265 | else if ((e->flags & EDGE_EH) && can_throw_internal (insn)) |
3266 | /* Keep the edges that correspond to exceptions thrown by |
3267 | this instruction and rematerialize the EDGE_ABNORMAL |
3268 | flag we just cleared above. */ |
3269 | { |
3270 | e->flags |= EDGE_ABNORMAL; |
3271 | ei_next (i: &ei); |
3272 | continue; |
3273 | } |
3274 | |
3275 | /* We do not need this edge. */ |
3276 | df_set_bb_dirty (bb); |
3277 | purged = true; |
3278 | remove_edge (e); |
3279 | } |
3280 | |
3281 | if (EDGE_COUNT (bb->succs) == 0 || !purged) |
3282 | return purged; |
3283 | |
3284 | if (dump_file) |
3285 | fprintf (stream: dump_file, format: "Purged edges from bb %i\n" , bb->index); |
3286 | |
3287 | if (!optimize) |
3288 | return purged; |
3289 | |
3290 | /* Redistribute probabilities. */ |
3291 | if (single_succ_p (bb)) |
3292 | { |
3293 | single_succ_edge (bb)->probability = profile_probability::always (); |
3294 | } |
3295 | else |
3296 | { |
3297 | note = find_reg_note (insn, REG_BR_PROB, NULL); |
3298 | if (!note) |
3299 | return purged; |
3300 | |
3301 | b = BRANCH_EDGE (bb); |
3302 | f = FALLTHRU_EDGE (bb); |
3303 | b->probability = profile_probability::from_reg_br_prob_note |
3304 | (XINT (note, 0)); |
3305 | f->probability = b->probability.invert (); |
3306 | } |
3307 | |
3308 | return purged; |
3309 | } |
3310 | else if (CALL_P (insn) && SIBLING_CALL_P (insn)) |
3311 | { |
3312 | /* First, there should not be any EH or ABCALL edges resulting |
3313 | from non-local gotos and the like. If there were, we shouldn't |
3314 | have created the sibcall in the first place. Second, there |
3315 | should of course never have been a fallthru edge. */ |
3316 | gcc_assert (single_succ_p (bb)); |
3317 | gcc_assert (single_succ_edge (bb)->flags |
3318 | == (EDGE_SIBCALL | EDGE_ABNORMAL)); |
3319 | |
3320 | return false; |
3321 | } |
3322 | |
3323 | /* If we don't see a jump insn, we don't know exactly why the block would |
3324 | have been broken at this point. Look for a simple, non-fallthru edge, |
3325 | as these are only created by conditional branches. If we find such an |
3326 | edge we know that there used to be a jump here and can then safely |
3327 | remove all non-fallthru edges. */ |
3328 | found = false; |
3329 | FOR_EACH_EDGE (e, ei, bb->succs) |
3330 | if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))) |
3331 | { |
3332 | found = true; |
3333 | break; |
3334 | } |
3335 | |
3336 | if (!found) |
3337 | return purged; |
3338 | |
3339 | /* Remove all but the fake and fallthru edges. The fake edge may be |
3340 | the only successor for this block in the case of noreturn |
3341 | calls. */ |
3342 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (i: ei)); ) |
3343 | { |
3344 | if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE))) |
3345 | { |
3346 | df_set_bb_dirty (bb); |
3347 | remove_edge (e); |
3348 | purged = true; |
3349 | } |
3350 | else |
3351 | ei_next (i: &ei); |
3352 | } |
3353 | |
3354 | gcc_assert (single_succ_p (bb)); |
3355 | |
3356 | single_succ_edge (bb)->probability = profile_probability::always (); |
3357 | |
3358 | if (dump_file) |
3359 | fprintf (stream: dump_file, format: "Purged non-fallthru edges from bb %i\n" , |
3360 | bb->index); |
3361 | return purged; |
3362 | } |
3363 | |
3364 | /* Search all basic blocks for potentially dead edges and purge them. Return |
3365 | true if some edge has been eliminated. */ |
3366 | |
3367 | bool |
3368 | purge_all_dead_edges (void) |
3369 | { |
3370 | bool purged = false; |
3371 | basic_block bb; |
3372 | |
3373 | FOR_EACH_BB_FN (bb, cfun) |
3374 | if (purge_dead_edges (bb)) |
3375 | purged = true; |
3376 | |
3377 | return purged; |
3378 | } |
3379 | |
3380 | /* This is used by a few passes that emit some instructions after abnormal |
3381 | calls, moving the basic block's end, while they in fact do want to emit |
3382 | them on the fallthru edge. Look for abnormal call edges, find backward |
3383 | the call in the block and insert the instructions on the edge instead. |
3384 | |
3385 | Similarly, handle instructions throwing exceptions internally. |
3386 | |
3387 | Return true when instructions have been found and inserted on edges. */ |
3388 | |
3389 | bool |
3390 | fixup_abnormal_edges (void) |
3391 | { |
3392 | bool inserted = false; |
3393 | basic_block bb; |
3394 | |
3395 | FOR_EACH_BB_FN (bb, cfun) |
3396 | { |
3397 | edge e; |
3398 | edge_iterator ei; |
3399 | |
3400 | /* Look for cases we are interested in - calls or instructions causing |
3401 | exceptions. */ |
3402 | FOR_EACH_EDGE (e, ei, bb->succs) |
3403 | if ((e->flags & EDGE_ABNORMAL_CALL) |
3404 | || ((e->flags & (EDGE_ABNORMAL | EDGE_EH)) |
3405 | == (EDGE_ABNORMAL | EDGE_EH))) |
3406 | break; |
3407 | |
3408 | if (e && !CALL_P (BB_END (bb)) && !can_throw_internal (BB_END (bb))) |
3409 | { |
3410 | rtx_insn *insn; |
3411 | |
3412 | /* Get past the new insns generated. Allow notes, as the insns |
3413 | may be already deleted. */ |
3414 | insn = BB_END (bb); |
3415 | while ((NONJUMP_INSN_P (insn) || NOTE_P (insn)) |
3416 | && !can_throw_internal (insn) |
3417 | && insn != BB_HEAD (bb)) |
3418 | insn = PREV_INSN (insn); |
3419 | |
3420 | if (CALL_P (insn) || can_throw_internal (insn)) |
3421 | { |
3422 | rtx_insn *stop, *next; |
3423 | |
3424 | e = find_fallthru_edge (edges: bb->succs); |
3425 | |
3426 | stop = NEXT_INSN (BB_END (bb)); |
3427 | BB_END (bb) = insn; |
3428 | |
3429 | for (insn = NEXT_INSN (insn); insn != stop; insn = next) |
3430 | { |
3431 | next = NEXT_INSN (insn); |
3432 | if (INSN_P (insn)) |
3433 | { |
3434 | delete_insn (insn); |
3435 | |
3436 | /* Sometimes there's still the return value USE. |
3437 | If it's placed after a trapping call (i.e. that |
3438 | call is the last insn anyway), we have no fallthru |
3439 | edge. Simply delete this use and don't try to insert |
3440 | on the non-existent edge. |
3441 | Similarly, sometimes a call that can throw is |
3442 | followed in the source with __builtin_unreachable (), |
3443 | meaning that there is UB if the call returns rather |
3444 | than throws. If there weren't any instructions |
3445 | following such calls before, supposedly even the ones |
3446 | we've deleted aren't significant and can be |
3447 | removed. */ |
3448 | if (e) |
3449 | { |
3450 | /* We're not deleting it, we're moving it. */ |
3451 | insn->set_undeleted (); |
3452 | SET_PREV_INSN (insn) = NULL_RTX; |
3453 | SET_NEXT_INSN (insn) = NULL_RTX; |
3454 | |
3455 | insert_insn_on_edge (pattern: insn, e); |
3456 | inserted = true; |
3457 | } |
3458 | } |
3459 | else if (!BARRIER_P (insn)) |
3460 | set_block_for_insn (insn, NULL); |
3461 | } |
3462 | } |
3463 | |
3464 | /* It may be that we don't find any trapping insn. In this |
3465 | case we discovered quite late that the insn that had been |
3466 | marked as can_throw_internal in fact couldn't trap at all. |
3467 | So we should in fact delete the EH edges out of the block. */ |
3468 | else |
3469 | purge_dead_edges (bb); |
3470 | } |
3471 | } |
3472 | |
3473 | return inserted; |
3474 | } |
3475 | |
3476 | /* Delete the unconditional jump INSN and adjust the CFG correspondingly. |
3477 | Note that the INSN should be deleted *after* removing dead edges, so |
3478 | that the kept edge is the fallthrough edge for a (set (pc) (pc)) |
3479 | but not for a (set (pc) (label_ref FOO)). */ |
3480 | |
3481 | void |
3482 | update_cfg_for_uncondjump (rtx_insn *insn) |
3483 | { |
3484 | basic_block bb = BLOCK_FOR_INSN (insn); |
3485 | gcc_assert (BB_END (bb) == insn); |
3486 | |
3487 | purge_dead_edges (bb); |
3488 | |
3489 | if (current_ir_type () != IR_RTL_CFGLAYOUT) |
3490 | { |
3491 | if (!find_fallthru_edge (edges: bb->succs)) |
3492 | { |
3493 | auto barrier = next_nonnote_nondebug_insn (insn); |
3494 | if (!barrier || !BARRIER_P (barrier)) |
3495 | emit_barrier_after (insn); |
3496 | } |
3497 | return; |
3498 | } |
3499 | |
3500 | delete_insn (insn); |
3501 | if (EDGE_COUNT (bb->succs) == 1) |
3502 | { |
3503 | rtx_insn *insn; |
3504 | |
3505 | single_succ_edge (bb)->flags |= EDGE_FALLTHRU; |
3506 | |
3507 | /* Remove barriers from the footer if there are any. */ |
3508 | for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn)) |
3509 | if (BARRIER_P (insn)) |
3510 | { |
3511 | if (PREV_INSN (insn)) |
3512 | SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); |
3513 | else |
3514 | BB_FOOTER (bb) = NEXT_INSN (insn); |
3515 | if (NEXT_INSN (insn)) |
3516 | SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); |
3517 | } |
3518 | else if (LABEL_P (insn)) |
3519 | break; |
3520 | } |
3521 | } |
3522 | |
3523 | /* Cut the insns from FIRST to LAST out of the insns stream. */ |
3524 | |
3525 | rtx_insn * |
3526 | unlink_insn_chain (rtx_insn *first, rtx_insn *last) |
3527 | { |
3528 | rtx_insn *prevfirst = PREV_INSN (insn: first); |
3529 | rtx_insn *nextlast = NEXT_INSN (insn: last); |
3530 | |
3531 | SET_PREV_INSN (first) = NULL; |
3532 | SET_NEXT_INSN (last) = NULL; |
3533 | if (prevfirst) |
3534 | SET_NEXT_INSN (prevfirst) = nextlast; |
3535 | if (nextlast) |
3536 | SET_PREV_INSN (nextlast) = prevfirst; |
3537 | else |
3538 | set_last_insn (prevfirst); |
3539 | if (!prevfirst) |
3540 | set_first_insn (nextlast); |
3541 | return first; |
3542 | } |
3543 | |
3544 | /* Skip over inter-block insns occurring after BB which are typically |
3545 | associated with BB (e.g., barriers). If there are any such insns, |
3546 | we return the last one. Otherwise, we return the end of BB. */ |
3547 | |
3548 | static rtx_insn * |
3549 | skip_insns_after_block (basic_block bb) |
3550 | { |
3551 | rtx_insn *insn, *last_insn, *next_head, *prev; |
3552 | |
3553 | next_head = NULL; |
3554 | if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3555 | next_head = BB_HEAD (bb->next_bb); |
3556 | |
3557 | for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; ) |
3558 | { |
3559 | if (insn == next_head) |
3560 | break; |
3561 | |
3562 | switch (GET_CODE (insn)) |
3563 | { |
3564 | case BARRIER: |
3565 | last_insn = insn; |
3566 | continue; |
3567 | |
3568 | case NOTE: |
3569 | gcc_assert (NOTE_KIND (insn) != NOTE_INSN_BLOCK_END); |
3570 | continue; |
3571 | |
3572 | case CODE_LABEL: |
3573 | if (NEXT_INSN (insn) |
3574 | && JUMP_TABLE_DATA_P (NEXT_INSN (insn))) |
3575 | { |
3576 | insn = NEXT_INSN (insn); |
3577 | last_insn = insn; |
3578 | continue; |
3579 | } |
3580 | break; |
3581 | |
3582 | default: |
3583 | break; |
3584 | } |
3585 | |
3586 | break; |
3587 | } |
3588 | |
3589 | /* It is possible to hit contradictory sequence. For instance: |
3590 | |
3591 | jump_insn |
3592 | NOTE_INSN_BLOCK_BEG |
3593 | barrier |
3594 | |
3595 | Where barrier belongs to jump_insn, but the note does not. This can be |
3596 | created by removing the basic block originally following |
3597 | NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */ |
3598 | |
3599 | for (insn = last_insn; insn != BB_END (bb); insn = prev) |
3600 | { |
3601 | prev = PREV_INSN (insn); |
3602 | if (NOTE_P (insn)) |
3603 | switch (NOTE_KIND (insn)) |
3604 | { |
3605 | case NOTE_INSN_BLOCK_END: |
3606 | gcc_unreachable (); |
3607 | break; |
3608 | case NOTE_INSN_DELETED: |
3609 | case NOTE_INSN_DELETED_LABEL: |
3610 | case NOTE_INSN_DELETED_DEBUG_LABEL: |
3611 | continue; |
3612 | default: |
3613 | reorder_insns (insn, insn, last_insn); |
3614 | } |
3615 | } |
3616 | |
3617 | return last_insn; |
3618 | } |
3619 | |
3620 | /* Locate or create a label for a given basic block. */ |
3621 | |
3622 | static rtx_insn * |
3623 | label_for_bb (basic_block bb) |
3624 | { |
3625 | rtx_insn *label = BB_HEAD (bb); |
3626 | |
3627 | if (!LABEL_P (label)) |
3628 | { |
3629 | if (dump_file) |
3630 | fprintf (stream: dump_file, format: "Emitting label for block %d\n" , bb->index); |
3631 | |
3632 | label = block_label (block: bb); |
3633 | } |
3634 | |
3635 | return label; |
3636 | } |
3637 | |
3638 | /* Locate the effective beginning and end of the insn chain for each |
3639 | block, as defined by skip_insns_after_block above. */ |
3640 | |
3641 | static void |
3642 | record_effective_endpoints (void) |
3643 | { |
3644 | rtx_insn *next_insn; |
3645 | basic_block bb; |
3646 | rtx_insn *insn; |
3647 | |
3648 | for (insn = get_insns (); |
3649 | insn |
3650 | && NOTE_P (insn) |
3651 | && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK; |
3652 | insn = NEXT_INSN (insn)) |
3653 | continue; |
3654 | /* No basic blocks at all? */ |
3655 | gcc_assert (insn); |
3656 | |
3657 | if (PREV_INSN (insn)) |
3658 | cfg_layout_function_header = |
3659 | unlink_insn_chain (first: get_insns (), last: PREV_INSN (insn)); |
3660 | else |
3661 | cfg_layout_function_header = NULL; |
3662 | |
3663 | next_insn = get_insns (); |
3664 | FOR_EACH_BB_FN (bb, cfun) |
3665 | { |
3666 | rtx_insn *end; |
3667 | |
3668 | if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb)) |
3669 | BB_HEADER (bb) = unlink_insn_chain (first: next_insn, |
3670 | last: PREV_INSN (BB_HEAD (bb))); |
3671 | end = skip_insns_after_block (bb); |
3672 | if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end) |
3673 | BB_FOOTER (bb) = unlink_insn_chain (first: NEXT_INSN (BB_END (bb)), last: end); |
3674 | next_insn = NEXT_INSN (BB_END (bb)); |
3675 | } |
3676 | |
3677 | cfg_layout_function_footer = next_insn; |
3678 | if (cfg_layout_function_footer) |
3679 | cfg_layout_function_footer = unlink_insn_chain (first: cfg_layout_function_footer, last: get_last_insn ()); |
3680 | } |
3681 | |
3682 | namespace { |
3683 | |
3684 | const pass_data pass_data_into_cfg_layout_mode = |
3685 | { |
3686 | .type: RTL_PASS, /* type */ |
3687 | .name: "into_cfglayout" , /* name */ |
3688 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
3689 | .tv_id: TV_CFG, /* tv_id */ |
3690 | .properties_required: 0, /* properties_required */ |
3691 | PROP_cfglayout, /* properties_provided */ |
3692 | .properties_destroyed: 0, /* properties_destroyed */ |
3693 | .todo_flags_start: 0, /* todo_flags_start */ |
3694 | .todo_flags_finish: 0, /* todo_flags_finish */ |
3695 | }; |
3696 | |
3697 | class pass_into_cfg_layout_mode : public rtl_opt_pass |
3698 | { |
3699 | public: |
3700 | pass_into_cfg_layout_mode (gcc::context *ctxt) |
3701 | : rtl_opt_pass (pass_data_into_cfg_layout_mode, ctxt) |
3702 | {} |
3703 | |
3704 | /* opt_pass methods: */ |
3705 | unsigned int execute (function *) final override |
3706 | { |
3707 | cfg_layout_initialize (0); |
3708 | return 0; |
3709 | } |
3710 | |
3711 | }; // class pass_into_cfg_layout_mode |
3712 | |
3713 | } // anon namespace |
3714 | |
3715 | rtl_opt_pass * |
3716 | make_pass_into_cfg_layout_mode (gcc::context *ctxt) |
3717 | { |
3718 | return new pass_into_cfg_layout_mode (ctxt); |
3719 | } |
3720 | |
3721 | namespace { |
3722 | |
3723 | const pass_data pass_data_outof_cfg_layout_mode = |
3724 | { |
3725 | .type: RTL_PASS, /* type */ |
3726 | .name: "outof_cfglayout" , /* name */ |
3727 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
3728 | .tv_id: TV_CFG, /* tv_id */ |
3729 | .properties_required: 0, /* properties_required */ |
3730 | .properties_provided: 0, /* properties_provided */ |
3731 | PROP_cfglayout, /* properties_destroyed */ |
3732 | .todo_flags_start: 0, /* todo_flags_start */ |
3733 | .todo_flags_finish: 0, /* todo_flags_finish */ |
3734 | }; |
3735 | |
3736 | class pass_outof_cfg_layout_mode : public rtl_opt_pass |
3737 | { |
3738 | public: |
3739 | pass_outof_cfg_layout_mode (gcc::context *ctxt) |
3740 | : rtl_opt_pass (pass_data_outof_cfg_layout_mode, ctxt) |
3741 | {} |
3742 | |
3743 | /* opt_pass methods: */ |
3744 | unsigned int execute (function *) final override; |
3745 | |
3746 | }; // class pass_outof_cfg_layout_mode |
3747 | |
3748 | unsigned int |
3749 | pass_outof_cfg_layout_mode::execute (function *fun) |
3750 | { |
3751 | basic_block bb; |
3752 | |
3753 | FOR_EACH_BB_FN (bb, fun) |
3754 | if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (fun)) |
3755 | bb->aux = bb->next_bb; |
3756 | |
3757 | cfg_layout_finalize (); |
3758 | |
3759 | return 0; |
3760 | } |
3761 | |
3762 | } // anon namespace |
3763 | |
3764 | rtl_opt_pass * |
3765 | make_pass_outof_cfg_layout_mode (gcc::context *ctxt) |
3766 | { |
3767 | return new pass_outof_cfg_layout_mode (ctxt); |
3768 | } |
3769 | |
3770 | |
3771 | /* Link the basic blocks in the correct order, compacting the basic |
3772 | block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this |
3773 | function also clears the basic block header and footer fields. |
3774 | |
3775 | This function is usually called after a pass (e.g. tracer) finishes |
3776 | some transformations while in cfglayout mode. The required sequence |
3777 | of the basic blocks is in a linked list along the bb->aux field. |
3778 | This functions re-links the basic block prev_bb and next_bb pointers |
3779 | accordingly, and it compacts and renumbers the blocks. |
3780 | |
3781 | FIXME: This currently works only for RTL, but the only RTL-specific |
3782 | bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved |
3783 | to GIMPLE a long time ago, but it doesn't relink the basic block |
3784 | chain. It could do that (to give better initial RTL) if this function |
3785 | is made IR-agnostic (and moved to cfganal.cc or cfg.cc while at it). */ |
3786 | |
3787 | void |
3788 | relink_block_chain (bool stay_in_cfglayout_mode) |
3789 | { |
3790 | basic_block bb, prev_bb; |
3791 | int index; |
3792 | |
3793 | /* Maybe dump the re-ordered sequence. */ |
3794 | if (dump_file) |
3795 | { |
3796 | fprintf (stream: dump_file, format: "Reordered sequence:\n" ); |
3797 | for (bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, index = |
3798 | NUM_FIXED_BLOCKS; |
3799 | bb; |
3800 | bb = (basic_block) bb->aux, index++) |
3801 | { |
3802 | fprintf (stream: dump_file, format: " %i " , index); |
3803 | if (get_bb_original (bb)) |
3804 | fprintf (stream: dump_file, format: "duplicate of %i\n" , |
3805 | get_bb_original (bb)->index); |
3806 | else if (forwarder_block_p (bb) |
3807 | && !LABEL_P (BB_HEAD (bb))) |
3808 | fprintf (stream: dump_file, format: "compensation\n" ); |
3809 | else |
3810 | fprintf (stream: dump_file, format: "bb %i\n" , bb->index); |
3811 | } |
3812 | } |
3813 | |
3814 | /* Now reorder the blocks. */ |
3815 | prev_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
3816 | bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; |
3817 | for (; bb; prev_bb = bb, bb = (basic_block) bb->aux) |
3818 | { |
3819 | bb->prev_bb = prev_bb; |
3820 | prev_bb->next_bb = bb; |
3821 | } |
3822 | prev_bb->next_bb = EXIT_BLOCK_PTR_FOR_FN (cfun); |
3823 | EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb = prev_bb; |
3824 | |
3825 | /* Then, clean up the aux fields. */ |
3826 | FOR_ALL_BB_FN (bb, cfun) |
3827 | { |
3828 | bb->aux = NULL; |
3829 | if (!stay_in_cfglayout_mode) |
3830 | BB_HEADER (bb) = BB_FOOTER (bb) = NULL; |
3831 | } |
3832 | |
3833 | /* Maybe reset the original copy tables, they are not valid anymore |
3834 | when we renumber the basic blocks in compact_blocks. If we are |
3835 | are going out of cfglayout mode, don't re-allocate the tables. */ |
3836 | if (original_copy_tables_initialized_p ()) |
3837 | free_original_copy_tables (); |
3838 | if (stay_in_cfglayout_mode) |
3839 | initialize_original_copy_tables (); |
3840 | |
3841 | /* Finally, put basic_block_info in the new order. */ |
3842 | compact_blocks (); |
3843 | } |
3844 | |
3845 | |
3846 | /* Given a reorder chain, rearrange the code to match. */ |
3847 | |
3848 | static void |
3849 | fixup_reorder_chain (void) |
3850 | { |
3851 | basic_block bb; |
3852 | rtx_insn *insn = NULL; |
3853 | |
3854 | if (cfg_layout_function_header) |
3855 | { |
3856 | set_first_insn (cfg_layout_function_header); |
3857 | insn = cfg_layout_function_header; |
3858 | while (NEXT_INSN (insn)) |
3859 | insn = NEXT_INSN (insn); |
3860 | } |
3861 | |
3862 | /* First do the bulk reordering -- rechain the blocks without regard to |
3863 | the needed changes to jumps and labels. */ |
3864 | |
3865 | for (bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; bb; bb = (basic_block) |
3866 | bb->aux) |
3867 | { |
3868 | if (BB_HEADER (bb)) |
3869 | { |
3870 | if (insn) |
3871 | SET_NEXT_INSN (insn) = BB_HEADER (bb); |
3872 | else |
3873 | set_first_insn (BB_HEADER (bb)); |
3874 | SET_PREV_INSN (BB_HEADER (bb)) = insn; |
3875 | insn = BB_HEADER (bb); |
3876 | while (NEXT_INSN (insn)) |
3877 | insn = NEXT_INSN (insn); |
3878 | } |
3879 | if (insn) |
3880 | SET_NEXT_INSN (insn) = BB_HEAD (bb); |
3881 | else |
3882 | set_first_insn (BB_HEAD (bb)); |
3883 | SET_PREV_INSN (BB_HEAD (bb)) = insn; |
3884 | insn = BB_END (bb); |
3885 | if (BB_FOOTER (bb)) |
3886 | { |
3887 | SET_NEXT_INSN (insn) = BB_FOOTER (bb); |
3888 | SET_PREV_INSN (BB_FOOTER (bb)) = insn; |
3889 | while (NEXT_INSN (insn)) |
3890 | insn = NEXT_INSN (insn); |
3891 | } |
3892 | } |
3893 | |
3894 | SET_NEXT_INSN (insn) = cfg_layout_function_footer; |
3895 | if (cfg_layout_function_footer) |
3896 | SET_PREV_INSN (cfg_layout_function_footer) = insn; |
3897 | |
3898 | while (NEXT_INSN (insn)) |
3899 | insn = NEXT_INSN (insn); |
3900 | |
3901 | set_last_insn (insn); |
3902 | if (flag_checking) |
3903 | verify_insn_chain (); |
3904 | |
3905 | /* Now add jumps and labels as needed to match the blocks new |
3906 | outgoing edges. */ |
3907 | |
3908 | bool remove_unreachable_blocks = false; |
3909 | for (bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; bb ; bb = (basic_block) |
3910 | bb->aux) |
3911 | { |
3912 | edge e_fall, e_taken, e; |
3913 | rtx_insn *bb_end_insn; |
3914 | rtx ret_label = NULL_RTX; |
3915 | basic_block nb; |
3916 | edge_iterator ei; |
3917 | bool asm_goto = false; |
3918 | |
3919 | if (EDGE_COUNT (bb->succs) == 0) |
3920 | continue; |
3921 | |
3922 | /* Find the old fallthru edge, and another non-EH edge for |
3923 | a taken jump. */ |
3924 | e_taken = e_fall = NULL; |
3925 | |
3926 | FOR_EACH_EDGE (e, ei, bb->succs) |
3927 | if (e->flags & EDGE_FALLTHRU) |
3928 | e_fall = e; |
3929 | else if (! (e->flags & EDGE_EH)) |
3930 | e_taken = e; |
3931 | |
3932 | bb_end_insn = BB_END (bb); |
3933 | if (rtx_jump_insn *bb_end_jump = dyn_cast <rtx_jump_insn *> (p: bb_end_insn)) |
3934 | { |
3935 | ret_label = JUMP_LABEL (bb_end_jump); |
3936 | if (any_condjump_p (bb_end_jump)) |
3937 | { |
3938 | /* This might happen if the conditional jump has side |
3939 | effects and could therefore not be optimized away. |
3940 | Make the basic block to end with a barrier in order |
3941 | to prevent rtl_verify_flow_info from complaining. */ |
3942 | if (!e_fall) |
3943 | { |
3944 | gcc_assert (!onlyjump_p (bb_end_jump) |
3945 | || returnjump_p (bb_end_jump) |
3946 | || (e_taken->flags & EDGE_CROSSING)); |
3947 | emit_barrier_after (bb_end_jump); |
3948 | continue; |
3949 | } |
3950 | |
3951 | /* If the old fallthru is still next, nothing to do. */ |
3952 | if (bb->aux == e_fall->dest |
3953 | || e_fall->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3954 | continue; |
3955 | |
3956 | /* The degenerated case of conditional jump jumping to the next |
3957 | instruction can happen for jumps with side effects. We need |
3958 | to construct a forwarder block and this will be done just |
3959 | fine by force_nonfallthru below. */ |
3960 | if (!e_taken) |
3961 | ; |
3962 | |
3963 | /* There is another special case: if *neither* block is next, |
3964 | such as happens at the very end of a function, then we'll |
3965 | need to add a new unconditional jump. Choose the taken |
3966 | edge based on known or assumed probability. */ |
3967 | else if (bb->aux != e_taken->dest) |
3968 | { |
3969 | rtx note = find_reg_note (bb_end_jump, REG_BR_PROB, 0); |
3970 | |
3971 | if (note |
3972 | && profile_probability::from_reg_br_prob_note |
3973 | (XINT (note, 0)) < profile_probability::even () |
3974 | && invert_jump (bb_end_jump, |
3975 | (e_fall->dest |
3976 | == EXIT_BLOCK_PTR_FOR_FN (cfun) |
3977 | ? NULL_RTX |
3978 | : label_for_bb (bb: e_fall->dest)), 0)) |
3979 | { |
3980 | e_fall->flags &= ~EDGE_FALLTHRU; |
3981 | gcc_checking_assert (could_fall_through |
3982 | (e_taken->src, e_taken->dest)); |
3983 | e_taken->flags |= EDGE_FALLTHRU; |
3984 | update_br_prob_note (bb); |
3985 | e = e_fall, e_fall = e_taken, e_taken = e; |
3986 | } |
3987 | } |
3988 | |
3989 | /* If the "jumping" edge is a crossing edge, and the fall |
3990 | through edge is non-crossing, leave things as they are. */ |
3991 | else if ((e_taken->flags & EDGE_CROSSING) |
3992 | && !(e_fall->flags & EDGE_CROSSING)) |
3993 | continue; |
3994 | |
3995 | /* Otherwise we can try to invert the jump. This will |
3996 | basically never fail, however, keep up the pretense. */ |
3997 | else if (invert_jump (bb_end_jump, |
3998 | (e_fall->dest |
3999 | == EXIT_BLOCK_PTR_FOR_FN (cfun) |
4000 | ? NULL_RTX |
4001 | : label_for_bb (bb: e_fall->dest)), 0)) |
4002 | { |
4003 | e_fall->flags &= ~EDGE_FALLTHRU; |
4004 | gcc_checking_assert (could_fall_through |
4005 | (e_taken->src, e_taken->dest)); |
4006 | e_taken->flags |= EDGE_FALLTHRU; |
4007 | update_br_prob_note (bb); |
4008 | if (LABEL_NUSES (ret_label) == 0 |
4009 | && single_pred_p (bb: e_taken->dest)) |
4010 | delete_insn (insn: as_a<rtx_insn *> (p: ret_label)); |
4011 | continue; |
4012 | } |
4013 | } |
4014 | else if (extract_asm_operands (PATTERN (insn: bb_end_insn)) != NULL) |
4015 | { |
4016 | /* If the old fallthru is still next or if |
4017 | asm goto doesn't have a fallthru (e.g. when followed by |
4018 | __builtin_unreachable ()), nothing to do. */ |
4019 | if (! e_fall |
4020 | || bb->aux == e_fall->dest |
4021 | || e_fall->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4022 | continue; |
4023 | |
4024 | /* Otherwise we'll have to use the fallthru fixup below. |
4025 | But avoid redirecting asm goto to EXIT. */ |
4026 | asm_goto = true; |
4027 | } |
4028 | else |
4029 | { |
4030 | /* Otherwise we have some return, switch or computed |
4031 | jump. In the 99% case, there should not have been a |
4032 | fallthru edge. */ |
4033 | gcc_assert (returnjump_p (bb_end_insn) || !e_fall); |
4034 | continue; |
4035 | } |
4036 | } |
4037 | else |
4038 | { |
4039 | /* No fallthru implies a noreturn function with EH edges, or |
4040 | something similarly bizarre. In any case, we don't need to |
4041 | do anything. */ |
4042 | if (! e_fall) |
4043 | continue; |
4044 | |
4045 | /* If the fallthru block is still next, nothing to do. */ |
4046 | if (bb->aux == e_fall->dest) |
4047 | continue; |
4048 | |
4049 | /* A fallthru to exit block. */ |
4050 | if (e_fall->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4051 | continue; |
4052 | } |
4053 | |
4054 | /* If E_FALL->dest is just a return block, then we can emit a |
4055 | return rather than a jump to the return block. */ |
4056 | rtx_insn *ret, *use; |
4057 | basic_block dest; |
4058 | if (!asm_goto |
4059 | && bb_is_just_return (e_fall->dest, &ret, &use) |
4060 | && ((PATTERN (insn: ret) == simple_return_rtx && targetm.have_simple_return ()) |
4061 | || (PATTERN (insn: ret) == ret_rtx && targetm.have_return ()))) |
4062 | { |
4063 | ret_label = PATTERN (insn: ret); |
4064 | dest = EXIT_BLOCK_PTR_FOR_FN (cfun); |
4065 | |
4066 | e_fall->flags &= ~EDGE_CROSSING; |
4067 | /* E_FALL->dest might become unreachable as a result of |
4068 | replacing the jump with a return. So arrange to remove |
4069 | unreachable blocks. */ |
4070 | remove_unreachable_blocks = true; |
4071 | } |
4072 | else |
4073 | { |
4074 | dest = e_fall->dest; |
4075 | } |
4076 | |
4077 | /* We got here if we need to add a new jump insn. |
4078 | Note force_nonfallthru can delete E_FALL and thus we have to |
4079 | save E_FALL->src prior to the call to force_nonfallthru. */ |
4080 | nb = force_nonfallthru_and_redirect (e: e_fall, target: dest, jump_label: ret_label); |
4081 | if (nb) |
4082 | { |
4083 | nb->aux = bb->aux; |
4084 | bb->aux = nb; |
4085 | /* Don't process this new block. */ |
4086 | bb = nb; |
4087 | } |
4088 | } |
4089 | |
4090 | relink_block_chain (/*stay_in_cfglayout_mode=*/false); |
4091 | |
4092 | /* Annoying special case - jump around dead jumptables left in the code. */ |
4093 | FOR_EACH_BB_FN (bb, cfun) |
4094 | { |
4095 | edge e = find_fallthru_edge (edges: bb->succs); |
4096 | |
4097 | if (e && !can_fallthru (src: e->src, target: e->dest)) |
4098 | force_nonfallthru (e); |
4099 | } |
4100 | |
4101 | /* Ensure goto_locus from edges has some instructions with that locus in RTL |
4102 | when not optimizing. */ |
4103 | if (!optimize && !DECL_IGNORED_P (current_function_decl)) |
4104 | FOR_EACH_BB_FN (bb, cfun) |
4105 | { |
4106 | edge e; |
4107 | edge_iterator ei; |
4108 | |
4109 | FOR_EACH_EDGE (e, ei, bb->succs) |
4110 | if (LOCATION_LOCUS (e->goto_locus) != UNKNOWN_LOCATION |
4111 | && !(e->flags & EDGE_ABNORMAL)) |
4112 | { |
4113 | edge e2; |
4114 | edge_iterator ei2; |
4115 | basic_block dest, nb; |
4116 | rtx_insn *end; |
4117 | |
4118 | insn = BB_END (e->src); |
4119 | end = PREV_INSN (BB_HEAD (e->src)); |
4120 | while (insn != end |
4121 | && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn))) |
4122 | insn = PREV_INSN (insn); |
4123 | if (insn != end |
4124 | && loc_equal (loc1: INSN_LOCATION (insn), loc2: e->goto_locus)) |
4125 | continue; |
4126 | if (simplejump_p (BB_END (e->src)) |
4127 | && !INSN_HAS_LOCATION (BB_END (e->src))) |
4128 | { |
4129 | INSN_LOCATION (BB_END (e->src)) = e->goto_locus; |
4130 | continue; |
4131 | } |
4132 | dest = e->dest; |
4133 | if (dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4134 | { |
4135 | /* Non-fallthru edges to the exit block cannot be split. */ |
4136 | if (!(e->flags & EDGE_FALLTHRU)) |
4137 | continue; |
4138 | } |
4139 | else |
4140 | { |
4141 | insn = BB_HEAD (dest); |
4142 | end = NEXT_INSN (BB_END (dest)); |
4143 | while (insn != end && !NONDEBUG_INSN_P (insn)) |
4144 | insn = NEXT_INSN (insn); |
4145 | if (insn != end && INSN_HAS_LOCATION (insn) |
4146 | && loc_equal (loc1: INSN_LOCATION (insn), loc2: e->goto_locus)) |
4147 | continue; |
4148 | } |
4149 | nb = split_edge (e); |
4150 | if (!INSN_P (BB_END (nb))) |
4151 | BB_END (nb) = emit_insn_after_noloc (gen_nop (), BB_END (nb), |
4152 | nb); |
4153 | INSN_LOCATION (BB_END (nb)) = e->goto_locus; |
4154 | |
4155 | /* If there are other incoming edges to the destination block |
4156 | with the same goto locus, redirect them to the new block as |
4157 | well, this can prevent other such blocks from being created |
4158 | in subsequent iterations of the loop. */ |
4159 | for (ei2 = ei_start (dest->preds); (e2 = ei_safe_edge (i: ei2)); ) |
4160 | if (LOCATION_LOCUS (e2->goto_locus) != UNKNOWN_LOCATION |
4161 | && !(e2->flags & (EDGE_ABNORMAL | EDGE_FALLTHRU)) |
4162 | && e->goto_locus == e2->goto_locus) |
4163 | redirect_edge_and_branch (e2, nb); |
4164 | else |
4165 | ei_next (i: &ei2); |
4166 | } |
4167 | } |
4168 | |
4169 | /* Replacing a jump with a return may have exposed an unreachable |
4170 | block. Conditionally remove them if such transformations were |
4171 | made. */ |
4172 | if (remove_unreachable_blocks) |
4173 | delete_unreachable_blocks (); |
4174 | } |
4175 | |
4176 | /* Perform sanity checks on the insn chain. |
4177 | 1. Check that next/prev pointers are consistent in both the forward and |
4178 | reverse direction. |
4179 | 2. Count insns in chain, going both directions, and check if equal. |
4180 | 3. Check that get_last_insn () returns the actual end of chain. */ |
4181 | |
4182 | DEBUG_FUNCTION void |
4183 | verify_insn_chain (void) |
4184 | { |
4185 | rtx_insn *x, *prevx, *nextx; |
4186 | int insn_cnt1, insn_cnt2; |
4187 | |
4188 | for (prevx = NULL, insn_cnt1 = 1, x = get_insns (); |
4189 | x != 0; |
4190 | prevx = x, insn_cnt1++, x = NEXT_INSN (insn: x)) |
4191 | gcc_assert (PREV_INSN (x) == prevx); |
4192 | |
4193 | gcc_assert (prevx == get_last_insn ()); |
4194 | |
4195 | for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn (); |
4196 | x != 0; |
4197 | nextx = x, insn_cnt2++, x = PREV_INSN (insn: x)) |
4198 | gcc_assert (NEXT_INSN (x) == nextx); |
4199 | |
4200 | gcc_assert (insn_cnt1 == insn_cnt2); |
4201 | } |
4202 | |
4203 | /* If we have assembler epilogues, the block falling through to exit must |
4204 | be the last one in the reordered chain when we reach final. Ensure |
4205 | that this condition is met. */ |
4206 | static void |
4207 | fixup_fallthru_exit_predecessor (void) |
4208 | { |
4209 | edge e; |
4210 | basic_block bb = NULL; |
4211 | |
4212 | /* This transformation is not valid before reload, because we might |
4213 | separate a call from the instruction that copies the return |
4214 | value. */ |
4215 | gcc_assert (reload_completed); |
4216 | |
4217 | e = find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds); |
4218 | if (e) |
4219 | bb = e->src; |
4220 | |
4221 | if (bb && bb->aux) |
4222 | { |
4223 | basic_block c = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; |
4224 | |
4225 | /* If the very first block is the one with the fall-through exit |
4226 | edge, we have to split that block. */ |
4227 | if (c == bb) |
4228 | { |
4229 | bb = split_block_after_labels (bb)->dest; |
4230 | bb->aux = c->aux; |
4231 | c->aux = bb; |
4232 | BB_FOOTER (bb) = BB_FOOTER (c); |
4233 | BB_FOOTER (c) = NULL; |
4234 | } |
4235 | |
4236 | while (c->aux != bb) |
4237 | c = (basic_block) c->aux; |
4238 | |
4239 | c->aux = bb->aux; |
4240 | while (c->aux) |
4241 | c = (basic_block) c->aux; |
4242 | |
4243 | c->aux = bb; |
4244 | bb->aux = NULL; |
4245 | } |
4246 | } |
4247 | |
4248 | /* In case there are more than one fallthru predecessors of exit, force that |
4249 | there is only one. */ |
4250 | |
4251 | static void |
4252 | force_one_exit_fallthru (void) |
4253 | { |
4254 | edge e, predecessor = NULL; |
4255 | bool more = false; |
4256 | edge_iterator ei; |
4257 | basic_block forwarder, bb; |
4258 | |
4259 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) |
4260 | if (e->flags & EDGE_FALLTHRU) |
4261 | { |
4262 | if (predecessor == NULL) |
4263 | predecessor = e; |
4264 | else |
4265 | { |
4266 | more = true; |
4267 | break; |
4268 | } |
4269 | } |
4270 | |
4271 | if (!more) |
4272 | return; |
4273 | |
4274 | /* Exit has several fallthru predecessors. Create a forwarder block for |
4275 | them. */ |
4276 | forwarder = split_edge (predecessor); |
4277 | for (ei = ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds); |
4278 | (e = ei_safe_edge (i: ei)); ) |
4279 | { |
4280 | if (e->src == forwarder |
4281 | || !(e->flags & EDGE_FALLTHRU)) |
4282 | ei_next (i: &ei); |
4283 | else |
4284 | redirect_edge_and_branch_force (e, forwarder); |
4285 | } |
4286 | |
4287 | /* Fix up the chain of blocks -- make FORWARDER immediately precede the |
4288 | exit block. */ |
4289 | FOR_EACH_BB_FN (bb, cfun) |
4290 | { |
4291 | if (bb->aux == NULL && bb != forwarder) |
4292 | { |
4293 | bb->aux = forwarder; |
4294 | break; |
4295 | } |
4296 | } |
4297 | } |
4298 | |
4299 | /* Return true in case it is possible to duplicate the basic block BB. */ |
4300 | |
4301 | static bool |
4302 | cfg_layout_can_duplicate_bb_p (const_basic_block bb) |
4303 | { |
4304 | /* Do not attempt to duplicate tablejumps, as we need to unshare |
4305 | the dispatch table. This is difficult to do, as the instructions |
4306 | computing jump destination may be hoisted outside the basic block. */ |
4307 | if (tablejump_p (BB_END (bb), NULL, NULL)) |
4308 | return false; |
4309 | |
4310 | /* Do not duplicate blocks containing insns that can't be copied. */ |
4311 | if (targetm.cannot_copy_insn_p) |
4312 | { |
4313 | rtx_insn *insn = BB_HEAD (bb); |
4314 | while (1) |
4315 | { |
4316 | if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn)) |
4317 | return false; |
4318 | if (insn == BB_END (bb)) |
4319 | break; |
4320 | insn = NEXT_INSN (insn); |
4321 | } |
4322 | } |
4323 | |
4324 | return true; |
4325 | } |
4326 | |
4327 | rtx_insn * |
4328 | duplicate_insn_chain (rtx_insn *from, rtx_insn *to, |
4329 | class loop *loop, copy_bb_data *id) |
4330 | { |
4331 | rtx_insn *insn, *next, *copy; |
4332 | rtx_note *last; |
4333 | |
4334 | /* Avoid updating of boundaries of previous basic block. The |
4335 | note will get removed from insn stream in fixup. */ |
4336 | last = emit_note (NOTE_INSN_DELETED); |
4337 | |
4338 | /* Create copy at the end of INSN chain. The chain will |
4339 | be reordered later. */ |
4340 | for (insn = from; insn != NEXT_INSN (insn: to); insn = NEXT_INSN (insn)) |
4341 | { |
4342 | switch (GET_CODE (insn)) |
4343 | { |
4344 | case DEBUG_INSN: |
4345 | /* Don't duplicate label debug insns. */ |
4346 | if (DEBUG_BIND_INSN_P (insn) |
4347 | && TREE_CODE (INSN_VAR_LOCATION_DECL (insn)) == LABEL_DECL) |
4348 | break; |
4349 | /* FALLTHRU */ |
4350 | case INSN: |
4351 | case CALL_INSN: |
4352 | case JUMP_INSN: |
4353 | copy = emit_copy_of_insn_after (insn, get_last_insn ()); |
4354 | if (JUMP_P (insn) && JUMP_LABEL (insn) != NULL_RTX |
4355 | && ANY_RETURN_P (JUMP_LABEL (insn))) |
4356 | JUMP_LABEL (copy) = JUMP_LABEL (insn); |
4357 | maybe_copy_prologue_epilogue_insn (insn, copy); |
4358 | /* If requested remap dependence info of cliques brought in |
4359 | via inlining. */ |
4360 | if (id) |
4361 | { |
4362 | subrtx_iterator::array_type array; |
4363 | FOR_EACH_SUBRTX (iter, array, PATTERN (insn), ALL) |
4364 | if (MEM_P (*iter) && MEM_EXPR (*iter)) |
4365 | { |
4366 | tree op = MEM_EXPR (*iter); |
4367 | if (TREE_CODE (op) == WITH_SIZE_EXPR) |
4368 | op = TREE_OPERAND (op, 0); |
4369 | while (handled_component_p (t: op)) |
4370 | op = TREE_OPERAND (op, 0); |
4371 | if ((TREE_CODE (op) == MEM_REF |
4372 | || TREE_CODE (op) == TARGET_MEM_REF) |
4373 | && MR_DEPENDENCE_CLIQUE (op) > 1 |
4374 | && (!loop |
4375 | || (MR_DEPENDENCE_CLIQUE (op) |
4376 | != loop->owned_clique))) |
4377 | { |
4378 | if (!id->dependence_map) |
4379 | id->dependence_map = new hash_map<dependence_hash, |
4380 | unsigned short>; |
4381 | bool existed; |
4382 | unsigned short &newc = id->dependence_map->get_or_insert |
4383 | (MR_DEPENDENCE_CLIQUE (op), existed: &existed); |
4384 | if (!existed) |
4385 | { |
4386 | gcc_assert |
4387 | (MR_DEPENDENCE_CLIQUE (op) <= cfun->last_clique); |
4388 | newc = ++cfun->last_clique; |
4389 | } |
4390 | /* We cannot adjust MR_DEPENDENCE_CLIQUE in-place |
4391 | since MEM_EXPR is shared so make a copy and |
4392 | walk to the subtree again. */ |
4393 | tree new_expr = unshare_expr (MEM_EXPR (*iter)); |
4394 | if (TREE_CODE (new_expr) == WITH_SIZE_EXPR) |
4395 | new_expr = TREE_OPERAND (new_expr, 0); |
4396 | while (handled_component_p (t: new_expr)) |
4397 | new_expr = TREE_OPERAND (new_expr, 0); |
4398 | MR_DEPENDENCE_CLIQUE (new_expr) = newc; |
4399 | set_mem_expr (const_cast <rtx> (*iter), new_expr); |
4400 | } |
4401 | } |
4402 | } |
4403 | break; |
4404 | |
4405 | case JUMP_TABLE_DATA: |
4406 | /* Avoid copying of dispatch tables. We never duplicate |
4407 | tablejumps, so this can hit only in case the table got |
4408 | moved far from original jump. |
4409 | Avoid copying following barrier as well if any |
4410 | (and debug insns in between). */ |
4411 | for (next = NEXT_INSN (insn); |
4412 | next != NEXT_INSN (insn: to); |
4413 | next = NEXT_INSN (insn: next)) |
4414 | if (!DEBUG_INSN_P (next)) |
4415 | break; |
4416 | if (next != NEXT_INSN (insn: to) && BARRIER_P (next)) |
4417 | insn = next; |
4418 | break; |
4419 | |
4420 | case CODE_LABEL: |
4421 | break; |
4422 | |
4423 | case BARRIER: |
4424 | emit_barrier (); |
4425 | break; |
4426 | |
4427 | case NOTE: |
4428 | switch (NOTE_KIND (insn)) |
4429 | { |
4430 | /* In case prologue is empty and function contain label |
4431 | in first BB, we may want to copy the block. */ |
4432 | case NOTE_INSN_PROLOGUE_END: |
4433 | |
4434 | case NOTE_INSN_DELETED: |
4435 | case NOTE_INSN_DELETED_LABEL: |
4436 | case NOTE_INSN_DELETED_DEBUG_LABEL: |
4437 | /* No problem to strip these. */ |
4438 | case NOTE_INSN_FUNCTION_BEG: |
4439 | /* There is always just single entry to function. */ |
4440 | case NOTE_INSN_BASIC_BLOCK: |
4441 | /* We should only switch text sections once. */ |
4442 | case NOTE_INSN_SWITCH_TEXT_SECTIONS: |
4443 | break; |
4444 | |
4445 | case NOTE_INSN_EPILOGUE_BEG: |
4446 | case NOTE_INSN_UPDATE_SJLJ_CONTEXT: |
4447 | emit_note_copy (as_a <rtx_note *> (p: insn)); |
4448 | break; |
4449 | |
4450 | default: |
4451 | /* All other notes should have already been eliminated. */ |
4452 | gcc_unreachable (); |
4453 | } |
4454 | break; |
4455 | default: |
4456 | gcc_unreachable (); |
4457 | } |
4458 | } |
4459 | insn = NEXT_INSN (insn: last); |
4460 | delete_insn (insn: last); |
4461 | return insn; |
4462 | } |
4463 | |
4464 | /* Create a duplicate of the basic block BB. */ |
4465 | |
4466 | static basic_block |
4467 | cfg_layout_duplicate_bb (basic_block bb, copy_bb_data *id) |
4468 | { |
4469 | rtx_insn *insn; |
4470 | basic_block new_bb; |
4471 | |
4472 | class loop *loop = (id && current_loops) ? bb->loop_father : NULL; |
4473 | |
4474 | insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb), loop, id); |
4475 | new_bb = create_basic_block (insn, |
4476 | insn ? get_last_insn () : NULL, |
4477 | EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb); |
4478 | |
4479 | BB_COPY_PARTITION (new_bb, bb); |
4480 | if (BB_HEADER (bb)) |
4481 | { |
4482 | insn = BB_HEADER (bb); |
4483 | while (NEXT_INSN (insn)) |
4484 | insn = NEXT_INSN (insn); |
4485 | insn = duplicate_insn_chain (BB_HEADER (bb), to: insn, loop, id); |
4486 | if (insn) |
4487 | BB_HEADER (new_bb) = unlink_insn_chain (first: insn, last: get_last_insn ()); |
4488 | } |
4489 | |
4490 | if (BB_FOOTER (bb)) |
4491 | { |
4492 | insn = BB_FOOTER (bb); |
4493 | while (NEXT_INSN (insn)) |
4494 | insn = NEXT_INSN (insn); |
4495 | insn = duplicate_insn_chain (BB_FOOTER (bb), to: insn, loop, id); |
4496 | if (insn) |
4497 | BB_FOOTER (new_bb) = unlink_insn_chain (first: insn, last: get_last_insn ()); |
4498 | } |
4499 | |
4500 | return new_bb; |
4501 | } |
4502 | |
4503 | |
4504 | /* Main entry point to this module - initialize the datastructures for |
4505 | CFG layout changes. It keeps LOOPS up-to-date if not null. |
4506 | |
4507 | FLAGS is a set of additional flags to pass to cleanup_cfg(). */ |
4508 | |
4509 | void |
4510 | cfg_layout_initialize (int flags) |
4511 | { |
4512 | rtx_insn_list *x; |
4513 | basic_block bb; |
4514 | |
4515 | /* Once bb partitioning is complete, cfg layout mode should not be |
4516 | re-entered. Entering cfg layout mode may require fixups. As an |
4517 | example, if edge forwarding performed when optimizing the cfg |
4518 | layout required moving a block from the hot to the cold |
4519 | section. This would create an illegal partitioning unless some |
4520 | manual fixup was performed. */ |
4521 | gcc_assert (!crtl->bb_reorder_complete || !crtl->has_bb_partition); |
4522 | |
4523 | initialize_original_copy_tables (); |
4524 | |
4525 | cfg_layout_rtl_register_cfg_hooks (); |
4526 | |
4527 | record_effective_endpoints (); |
4528 | |
4529 | /* Make sure that the targets of non local gotos are marked. */ |
4530 | for (x = nonlocal_goto_handler_labels; x; x = x->next ()) |
4531 | { |
4532 | bb = BLOCK_FOR_INSN (insn: x->insn ()); |
4533 | bb->flags |= BB_NON_LOCAL_GOTO_TARGET; |
4534 | } |
4535 | |
4536 | cleanup_cfg (CLEANUP_CFGLAYOUT | flags); |
4537 | } |
4538 | |
4539 | /* Splits superblocks. */ |
4540 | void |
4541 | break_superblocks (void) |
4542 | { |
4543 | bool need = false; |
4544 | basic_block bb; |
4545 | |
4546 | auto_sbitmap superblocks (last_basic_block_for_fn (cfun)); |
4547 | bitmap_clear (superblocks); |
4548 | |
4549 | FOR_EACH_BB_FN (bb, cfun) |
4550 | if (bb->flags & BB_SUPERBLOCK) |
4551 | { |
4552 | bb->flags &= ~BB_SUPERBLOCK; |
4553 | bitmap_set_bit (map: superblocks, bitno: bb->index); |
4554 | need = true; |
4555 | } |
4556 | |
4557 | if (need) |
4558 | { |
4559 | rebuild_jump_labels (get_insns ()); |
4560 | find_many_sub_basic_blocks (superblocks); |
4561 | } |
4562 | } |
4563 | |
4564 | /* Finalize the changes: reorder insn list according to the sequence specified |
4565 | by aux pointers, enter compensation code, rebuild scope forest. */ |
4566 | |
4567 | void |
4568 | cfg_layout_finalize (void) |
4569 | { |
4570 | free_dominance_info (CDI_DOMINATORS); |
4571 | force_one_exit_fallthru (); |
4572 | rtl_register_cfg_hooks (); |
4573 | if (reload_completed && !targetm.have_epilogue ()) |
4574 | fixup_fallthru_exit_predecessor (); |
4575 | fixup_reorder_chain (); |
4576 | |
4577 | rebuild_jump_labels (get_insns ()); |
4578 | delete_dead_jumptables (); |
4579 | |
4580 | if (flag_checking) |
4581 | verify_insn_chain (); |
4582 | checking_verify_flow_info (); |
4583 | } |
4584 | |
4585 | |
4586 | /* Same as split_block but update cfg_layout structures. */ |
4587 | |
4588 | static basic_block |
4589 | cfg_layout_split_block (basic_block bb, void *insnp) |
4590 | { |
4591 | rtx insn = (rtx) insnp; |
4592 | basic_block new_bb = rtl_split_block (bb, insnp: insn); |
4593 | |
4594 | BB_FOOTER (new_bb) = BB_FOOTER (bb); |
4595 | BB_FOOTER (bb) = NULL; |
4596 | |
4597 | return new_bb; |
4598 | } |
4599 | |
4600 | /* Redirect Edge to DEST. */ |
4601 | static edge |
4602 | cfg_layout_redirect_edge_and_branch (edge e, basic_block dest) |
4603 | { |
4604 | basic_block src = e->src; |
4605 | edge ret; |
4606 | |
4607 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
4608 | return NULL; |
4609 | |
4610 | if (e->dest == dest) |
4611 | return e; |
4612 | |
4613 | if (e->flags & EDGE_CROSSING |
4614 | && BB_PARTITION (e->src) == BB_PARTITION (dest) |
4615 | && simplejump_p (BB_END (src))) |
4616 | { |
4617 | if (dump_file) |
4618 | fprintf (stream: dump_file, |
4619 | format: "Removing crossing jump while redirecting edge form %i to %i\n" , |
4620 | e->src->index, dest->index); |
4621 | delete_insn (BB_END (src)); |
4622 | remove_barriers_from_footer (bb: src); |
4623 | e->flags |= EDGE_FALLTHRU; |
4624 | } |
4625 | |
4626 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4627 | && (ret = try_redirect_by_replacing_jump (e, target: dest, in_cfglayout: true))) |
4628 | { |
4629 | df_set_bb_dirty (src); |
4630 | return ret; |
4631 | } |
4632 | |
4633 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4634 | && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX)) |
4635 | { |
4636 | if (dump_file) |
4637 | fprintf (stream: dump_file, format: "Redirecting entry edge from bb %i to %i\n" , |
4638 | e->src->index, dest->index); |
4639 | |
4640 | df_set_bb_dirty (e->src); |
4641 | redirect_edge_succ (e, dest); |
4642 | return e; |
4643 | } |
4644 | |
4645 | /* Redirect_edge_and_branch may decide to turn branch into fallthru edge |
4646 | in the case the basic block appears to be in sequence. Avoid this |
4647 | transformation. */ |
4648 | |
4649 | if (e->flags & EDGE_FALLTHRU) |
4650 | { |
4651 | /* Redirect any branch edges unified with the fallthru one. */ |
4652 | if (JUMP_P (BB_END (src)) |
4653 | && label_is_jump_target_p (BB_HEAD (e->dest), |
4654 | BB_END (src))) |
4655 | { |
4656 | edge redirected; |
4657 | |
4658 | if (dump_file) |
4659 | fprintf (stream: dump_file, format: "Fallthru edge unified with branch " |
4660 | "%i->%i redirected to %i\n" , |
4661 | e->src->index, e->dest->index, dest->index); |
4662 | e->flags &= ~EDGE_FALLTHRU; |
4663 | redirected = redirect_branch_edge (e, target: dest); |
4664 | gcc_assert (redirected); |
4665 | redirected->flags |= EDGE_FALLTHRU; |
4666 | df_set_bb_dirty (redirected->src); |
4667 | return redirected; |
4668 | } |
4669 | /* In case we are redirecting fallthru edge to the branch edge |
4670 | of conditional jump, remove it. */ |
4671 | if (EDGE_COUNT (src->succs) == 2) |
4672 | { |
4673 | /* Find the edge that is different from E. */ |
4674 | edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e); |
4675 | |
4676 | if (s->dest == dest |
4677 | && any_condjump_p (BB_END (src)) |
4678 | && onlyjump_p (BB_END (src))) |
4679 | delete_insn (BB_END (src)); |
4680 | } |
4681 | if (dump_file) |
4682 | fprintf (stream: dump_file, format: "Redirecting fallthru edge %i->%i to %i\n" , |
4683 | e->src->index, e->dest->index, dest->index); |
4684 | ret = redirect_edge_succ_nodup (e, dest); |
4685 | } |
4686 | else |
4687 | ret = redirect_branch_edge (e, target: dest); |
4688 | |
4689 | if (!ret) |
4690 | return NULL; |
4691 | |
4692 | fixup_partition_crossing (e: ret); |
4693 | /* We don't want simplejumps in the insn stream during cfglayout. */ |
4694 | gcc_assert (!simplejump_p (BB_END (src)) || CROSSING_JUMP_P (BB_END (src))); |
4695 | |
4696 | df_set_bb_dirty (src); |
4697 | return ret; |
4698 | } |
4699 | |
4700 | /* Simple wrapper as we always can redirect fallthru edges. */ |
4701 | static basic_block |
4702 | cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest) |
4703 | { |
4704 | edge redirected = cfg_layout_redirect_edge_and_branch (e, dest); |
4705 | |
4706 | gcc_assert (redirected); |
4707 | return NULL; |
4708 | } |
4709 | |
4710 | /* Same as delete_basic_block but update cfg_layout structures. */ |
4711 | |
4712 | static void |
4713 | cfg_layout_delete_block (basic_block bb) |
4714 | { |
4715 | rtx_insn *insn, *next, *prev = PREV_INSN (BB_HEAD (bb)), *remaints; |
4716 | rtx_insn **to; |
4717 | |
4718 | if (BB_HEADER (bb)) |
4719 | { |
4720 | next = BB_HEAD (bb); |
4721 | if (prev) |
4722 | SET_NEXT_INSN (prev) = BB_HEADER (bb); |
4723 | else |
4724 | set_first_insn (BB_HEADER (bb)); |
4725 | SET_PREV_INSN (BB_HEADER (bb)) = prev; |
4726 | insn = BB_HEADER (bb); |
4727 | while (NEXT_INSN (insn)) |
4728 | insn = NEXT_INSN (insn); |
4729 | SET_NEXT_INSN (insn) = next; |
4730 | SET_PREV_INSN (next) = insn; |
4731 | } |
4732 | next = NEXT_INSN (BB_END (bb)); |
4733 | if (BB_FOOTER (bb)) |
4734 | { |
4735 | insn = BB_FOOTER (bb); |
4736 | while (insn) |
4737 | { |
4738 | if (BARRIER_P (insn)) |
4739 | { |
4740 | if (PREV_INSN (insn)) |
4741 | SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); |
4742 | else |
4743 | BB_FOOTER (bb) = NEXT_INSN (insn); |
4744 | if (NEXT_INSN (insn)) |
4745 | SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); |
4746 | } |
4747 | if (LABEL_P (insn)) |
4748 | break; |
4749 | insn = NEXT_INSN (insn); |
4750 | } |
4751 | if (BB_FOOTER (bb)) |
4752 | { |
4753 | insn = BB_END (bb); |
4754 | SET_NEXT_INSN (insn) = BB_FOOTER (bb); |
4755 | SET_PREV_INSN (BB_FOOTER (bb)) = insn; |
4756 | while (NEXT_INSN (insn)) |
4757 | insn = NEXT_INSN (insn); |
4758 | SET_NEXT_INSN (insn) = next; |
4759 | if (next) |
4760 | SET_PREV_INSN (next) = insn; |
4761 | else |
4762 | set_last_insn (insn); |
4763 | } |
4764 | } |
4765 | if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4766 | to = &BB_HEADER (bb->next_bb); |
4767 | else |
4768 | to = &cfg_layout_function_footer; |
4769 | |
4770 | rtl_delete_block (b: bb); |
4771 | |
4772 | if (prev) |
4773 | prev = NEXT_INSN (insn: prev); |
4774 | else |
4775 | prev = get_insns (); |
4776 | if (next) |
4777 | next = PREV_INSN (insn: next); |
4778 | else |
4779 | next = get_last_insn (); |
4780 | |
4781 | if (next && NEXT_INSN (insn: next) != prev) |
4782 | { |
4783 | remaints = unlink_insn_chain (first: prev, last: next); |
4784 | insn = remaints; |
4785 | while (NEXT_INSN (insn)) |
4786 | insn = NEXT_INSN (insn); |
4787 | SET_NEXT_INSN (insn) = *to; |
4788 | if (*to) |
4789 | SET_PREV_INSN (*to) = insn; |
4790 | *to = remaints; |
4791 | } |
4792 | } |
4793 | |
4794 | /* Return true when blocks A and B can be safely merged. */ |
4795 | |
4796 | static bool |
4797 | cfg_layout_can_merge_blocks_p (basic_block a, basic_block b) |
4798 | { |
4799 | /* If we are partitioning hot/cold basic blocks, we don't want to |
4800 | mess up unconditional or indirect jumps that cross between hot |
4801 | and cold sections. |
4802 | |
4803 | Basic block partitioning may result in some jumps that appear to |
4804 | be optimizable (or blocks that appear to be mergeable), but which really |
4805 | must be left untouched (they are required to make it safely across |
4806 | partition boundaries). See the comments at the top of |
4807 | bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */ |
4808 | |
4809 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
4810 | return false; |
4811 | |
4812 | /* Protect the loop latches. */ |
4813 | if (current_loops && b->loop_father->latch == b) |
4814 | return false; |
4815 | |
4816 | /* If we would end up moving B's instructions, make sure it doesn't fall |
4817 | through into the exit block, since we cannot recover from a fallthrough |
4818 | edge into the exit block occurring in the middle of a function. */ |
4819 | if (NEXT_INSN (BB_END (a)) != BB_HEAD (b)) |
4820 | { |
4821 | edge e = find_fallthru_edge (edges: b->succs); |
4822 | if (e && e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4823 | return false; |
4824 | } |
4825 | |
4826 | /* There must be exactly one edge in between the blocks. */ |
4827 | return (single_succ_p (bb: a) |
4828 | && single_succ (bb: a) == b |
4829 | && single_pred_p (bb: b) == 1 |
4830 | && a != b |
4831 | /* Must be simple edge. */ |
4832 | && !(single_succ_edge (bb: a)->flags & EDGE_COMPLEX) |
4833 | && a != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4834 | && b != EXIT_BLOCK_PTR_FOR_FN (cfun) |
4835 | /* If the jump insn has side effects, we can't kill the edge. |
4836 | When not optimizing, try_redirect_by_replacing_jump will |
4837 | not allow us to redirect an edge by replacing a table jump. */ |
4838 | && (!JUMP_P (BB_END (a)) |
4839 | || ((!optimize || reload_completed) |
4840 | ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a))))); |
4841 | } |
4842 | |
4843 | /* Merge block A and B. The blocks must be mergeable. */ |
4844 | |
4845 | static void |
4846 | cfg_layout_merge_blocks (basic_block a, basic_block b) |
4847 | { |
4848 | /* If B is a forwarder block whose outgoing edge has no location, we'll |
4849 | propagate the locus of the edge between A and B onto it. */ |
4850 | const bool forward_edge_locus |
4851 | = (b->flags & BB_FORWARDER_BLOCK) != 0 |
4852 | && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION; |
4853 | rtx_insn *insn; |
4854 | |
4855 | gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b)); |
4856 | |
4857 | if (dump_file) |
4858 | fprintf (stream: dump_file, format: "Merging block %d into block %d...\n" , b->index, |
4859 | a->index); |
4860 | |
4861 | /* If there was a CODE_LABEL beginning B, delete it. */ |
4862 | if (LABEL_P (BB_HEAD (b))) |
4863 | { |
4864 | delete_insn (BB_HEAD (b)); |
4865 | } |
4866 | |
4867 | /* We should have fallthru edge in a, or we can do dummy redirection to get |
4868 | it cleaned up. */ |
4869 | if (JUMP_P (BB_END (a))) |
4870 | try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), target: b, in_cfglayout: true); |
4871 | gcc_assert (!JUMP_P (BB_END (a))); |
4872 | |
4873 | /* If not optimizing, preserve the locus of the single edge between |
4874 | blocks A and B if necessary by emitting a nop. */ |
4875 | if (!optimize |
4876 | && !forward_edge_locus |
4877 | && !DECL_IGNORED_P (current_function_decl)) |
4878 | emit_nop_for_unique_locus_between (a, b); |
4879 | |
4880 | /* Move things from b->footer after a->footer. */ |
4881 | if (BB_FOOTER (b)) |
4882 | { |
4883 | if (!BB_FOOTER (a)) |
4884 | BB_FOOTER (a) = BB_FOOTER (b); |
4885 | else |
4886 | { |
4887 | rtx_insn *last = BB_FOOTER (a); |
4888 | |
4889 | while (NEXT_INSN (insn: last)) |
4890 | last = NEXT_INSN (insn: last); |
4891 | SET_NEXT_INSN (last) = BB_FOOTER (b); |
4892 | SET_PREV_INSN (BB_FOOTER (b)) = last; |
4893 | } |
4894 | BB_FOOTER (b) = NULL; |
4895 | } |
4896 | |
4897 | /* Move things from b->header before a->footer. |
4898 | Note that this may include dead tablejump data, but we don't clean |
4899 | those up until we go out of cfglayout mode. */ |
4900 | if (BB_HEADER (b)) |
4901 | { |
4902 | if (! BB_FOOTER (a)) |
4903 | BB_FOOTER (a) = BB_HEADER (b); |
4904 | else |
4905 | { |
4906 | rtx_insn *last = BB_HEADER (b); |
4907 | |
4908 | while (NEXT_INSN (insn: last)) |
4909 | last = NEXT_INSN (insn: last); |
4910 | SET_NEXT_INSN (last) = BB_FOOTER (a); |
4911 | SET_PREV_INSN (BB_FOOTER (a)) = last; |
4912 | BB_FOOTER (a) = BB_HEADER (b); |
4913 | } |
4914 | BB_HEADER (b) = NULL; |
4915 | } |
4916 | |
4917 | /* In the case basic blocks are not adjacent, move them around. */ |
4918 | if (NEXT_INSN (BB_END (a)) != BB_HEAD (b)) |
4919 | { |
4920 | insn = unlink_insn_chain (BB_HEAD (b), BB_END (b)); |
4921 | |
4922 | emit_insn_after_noloc (insn, BB_END (a), a); |
4923 | } |
4924 | /* Otherwise just re-associate the instructions. */ |
4925 | else |
4926 | { |
4927 | insn = BB_HEAD (b); |
4928 | BB_END (a) = BB_END (b); |
4929 | } |
4930 | |
4931 | /* emit_insn_after_noloc doesn't call df_insn_change_bb. |
4932 | We need to explicitly call. */ |
4933 | update_bb_for_insn_chain (begin: insn, BB_END (b), bb: a); |
4934 | |
4935 | /* Skip possible DELETED_LABEL insn. */ |
4936 | if (!NOTE_INSN_BASIC_BLOCK_P (insn)) |
4937 | insn = NEXT_INSN (insn); |
4938 | gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn)); |
4939 | BB_HEAD (b) = BB_END (b) = NULL; |
4940 | delete_insn (insn); |
4941 | |
4942 | df_bb_delete (b->index); |
4943 | |
4944 | if (forward_edge_locus) |
4945 | EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus; |
4946 | |
4947 | if (dump_file) |
4948 | fprintf (stream: dump_file, format: "Merged blocks %d and %d.\n" , a->index, b->index); |
4949 | } |
4950 | |
4951 | /* Split edge E. */ |
4952 | |
4953 | static basic_block |
4954 | cfg_layout_split_edge (edge e) |
4955 | { |
4956 | basic_block new_bb = |
4957 | create_basic_block (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4958 | ? NEXT_INSN (BB_END (e->src)) : get_insns (), |
4959 | NULL_RTX, e->src); |
4960 | |
4961 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4962 | BB_COPY_PARTITION (new_bb, e->src); |
4963 | else |
4964 | BB_COPY_PARTITION (new_bb, e->dest); |
4965 | make_edge (new_bb, e->dest, EDGE_FALLTHRU); |
4966 | redirect_edge_and_branch_force (e, new_bb); |
4967 | |
4968 | return new_bb; |
4969 | } |
4970 | |
4971 | /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */ |
4972 | |
4973 | static void |
4974 | rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED) |
4975 | { |
4976 | } |
4977 | |
4978 | /* Return true if BB contains only labels or non-executable |
4979 | instructions. */ |
4980 | |
4981 | static bool |
4982 | rtl_block_empty_p (basic_block bb) |
4983 | { |
4984 | rtx_insn *insn; |
4985 | |
4986 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4987 | || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4988 | return true; |
4989 | |
4990 | FOR_BB_INSNS (bb, insn) |
4991 | if (NONDEBUG_INSN_P (insn) |
4992 | && (!any_uncondjump_p (insn) || !onlyjump_p (insn))) |
4993 | return false; |
4994 | |
4995 | return true; |
4996 | } |
4997 | |
4998 | /* Split a basic block if it ends with a conditional branch and if |
4999 | the other part of the block is not empty. */ |
5000 | |
5001 | static basic_block |
5002 | rtl_split_block_before_cond_jump (basic_block bb) |
5003 | { |
5004 | rtx_insn *insn; |
5005 | rtx_insn *split_point = NULL; |
5006 | rtx_insn *last = NULL; |
5007 | bool found_code = false; |
5008 | |
5009 | FOR_BB_INSNS (bb, insn) |
5010 | { |
5011 | if (any_condjump_p (insn)) |
5012 | split_point = last; |
5013 | else if (NONDEBUG_INSN_P (insn)) |
5014 | found_code = true; |
5015 | last = insn; |
5016 | } |
5017 | |
5018 | /* Did not find everything. */ |
5019 | if (found_code && split_point) |
5020 | return split_block (bb, split_point)->dest; |
5021 | else |
5022 | return NULL; |
5023 | } |
5024 | |
5025 | /* Return true if BB ends with a call, possibly followed by some |
5026 | instructions that must stay with the call, false otherwise. */ |
5027 | |
5028 | static bool |
5029 | rtl_block_ends_with_call_p (basic_block bb) |
5030 | { |
5031 | rtx_insn *insn = BB_END (bb); |
5032 | |
5033 | while (!CALL_P (insn) |
5034 | && insn != BB_HEAD (bb) |
5035 | && (keep_with_call_p (insn) |
5036 | || NOTE_P (insn) |
5037 | || DEBUG_INSN_P (insn))) |
5038 | insn = PREV_INSN (insn); |
5039 | return (CALL_P (insn)); |
5040 | } |
5041 | |
5042 | /* Return true if BB ends with a conditional branch, false otherwise. */ |
5043 | |
5044 | static bool |
5045 | rtl_block_ends_with_condjump_p (const_basic_block bb) |
5046 | { |
5047 | return any_condjump_p (BB_END (bb)); |
5048 | } |
5049 | |
5050 | /* Return true if we need to add fake edge to exit. |
5051 | Helper function for rtl_flow_call_edges_add. */ |
5052 | |
5053 | static bool |
5054 | need_fake_edge_p (const rtx_insn *insn) |
5055 | { |
5056 | if (!INSN_P (insn)) |
5057 | return false; |
5058 | |
5059 | if ((CALL_P (insn) |
5060 | && !SIBLING_CALL_P (insn) |
5061 | && !find_reg_note (insn, REG_NORETURN, NULL) |
5062 | && !(RTL_CONST_OR_PURE_CALL_P (insn)))) |
5063 | return true; |
5064 | |
5065 | return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS |
5066 | && MEM_VOLATILE_P (PATTERN (insn))) |
5067 | || (GET_CODE (PATTERN (insn)) == PARALLEL |
5068 | && asm_noperands (insn) != -1 |
5069 | && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0))) |
5070 | || GET_CODE (PATTERN (insn)) == ASM_INPUT); |
5071 | } |
5072 | |
5073 | /* Add fake edges to the function exit for any non constant and non noreturn |
5074 | calls, volatile inline assembly in the bitmap of blocks specified by |
5075 | BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks |
5076 | that were split. |
5077 | |
5078 | The goal is to expose cases in which entering a basic block does not imply |
5079 | that all subsequent instructions must be executed. */ |
5080 | |
5081 | static int |
5082 | rtl_flow_call_edges_add (sbitmap blocks) |
5083 | { |
5084 | int i; |
5085 | int blocks_split = 0; |
5086 | int last_bb = last_basic_block_for_fn (cfun); |
5087 | bool check_last_block = false; |
5088 | |
5089 | if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
5090 | return 0; |
5091 | |
5092 | if (! blocks) |
5093 | check_last_block = true; |
5094 | else |
5095 | check_last_block = bitmap_bit_p (map: blocks, |
5096 | EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb->index); |
5097 | |
5098 | /* In the last basic block, before epilogue generation, there will be |
5099 | a fallthru edge to EXIT. Special care is required if the last insn |
5100 | of the last basic block is a call because make_edge folds duplicate |
5101 | edges, which would result in the fallthru edge also being marked |
5102 | fake, which would result in the fallthru edge being removed by |
5103 | remove_fake_edges, which would result in an invalid CFG. |
5104 | |
5105 | Moreover, we can't elide the outgoing fake edge, since the block |
5106 | profiler needs to take this into account in order to solve the minimal |
5107 | spanning tree in the case that the call doesn't return. |
5108 | |
5109 | Handle this by adding a dummy instruction in a new last basic block. */ |
5110 | if (check_last_block) |
5111 | { |
5112 | basic_block bb = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
5113 | rtx_insn *insn = BB_END (bb); |
5114 | |
5115 | /* Back up past insns that must be kept in the same block as a call. */ |
5116 | while (insn != BB_HEAD (bb) |
5117 | && keep_with_call_p (insn)) |
5118 | insn = PREV_INSN (insn); |
5119 | |
5120 | if (need_fake_edge_p (insn)) |
5121 | { |
5122 | edge e; |
5123 | |
5124 | e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun)); |
5125 | if (e) |
5126 | { |
5127 | insert_insn_on_edge (pattern: gen_use (const0_rtx), e); |
5128 | commit_edge_insertions (); |
5129 | } |
5130 | } |
5131 | } |
5132 | |
5133 | /* Now add fake edges to the function exit for any non constant |
5134 | calls since there is no way that we can determine if they will |
5135 | return or not... */ |
5136 | |
5137 | for (i = NUM_FIXED_BLOCKS; i < last_bb; i++) |
5138 | { |
5139 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); |
5140 | rtx_insn *insn; |
5141 | rtx_insn *prev_insn; |
5142 | |
5143 | if (!bb) |
5144 | continue; |
5145 | |
5146 | if (blocks && !bitmap_bit_p (map: blocks, bitno: i)) |
5147 | continue; |
5148 | |
5149 | for (insn = BB_END (bb); ; insn = prev_insn) |
5150 | { |
5151 | prev_insn = PREV_INSN (insn); |
5152 | if (need_fake_edge_p (insn)) |
5153 | { |
5154 | edge e; |
5155 | rtx_insn *split_at_insn = insn; |
5156 | |
5157 | /* Don't split the block between a call and an insn that should |
5158 | remain in the same block as the call. */ |
5159 | if (CALL_P (insn)) |
5160 | while (split_at_insn != BB_END (bb) |
5161 | && keep_with_call_p (NEXT_INSN (insn: split_at_insn))) |
5162 | split_at_insn = NEXT_INSN (insn: split_at_insn); |
5163 | |
5164 | /* The handling above of the final block before the epilogue |
5165 | should be enough to verify that there is no edge to the exit |
5166 | block in CFG already. Calling make_edge in such case would |
5167 | cause us to mark that edge as fake and remove it later. */ |
5168 | |
5169 | if (flag_checking && split_at_insn == BB_END (bb)) |
5170 | { |
5171 | e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun)); |
5172 | gcc_assert (e == NULL); |
5173 | } |
5174 | |
5175 | /* Note that the following may create a new basic block |
5176 | and renumber the existing basic blocks. */ |
5177 | if (split_at_insn != BB_END (bb)) |
5178 | { |
5179 | e = split_block (bb, split_at_insn); |
5180 | if (e) |
5181 | blocks_split++; |
5182 | } |
5183 | |
5184 | edge ne = make_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE); |
5185 | ne->probability = profile_probability::guessed_never (); |
5186 | } |
5187 | |
5188 | if (insn == BB_HEAD (bb)) |
5189 | break; |
5190 | } |
5191 | } |
5192 | |
5193 | if (blocks_split) |
5194 | verify_flow_info (); |
5195 | |
5196 | return blocks_split; |
5197 | } |
5198 | |
5199 | /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is |
5200 | the conditional branch target, SECOND_HEAD should be the fall-thru |
5201 | there is no need to handle this here the loop versioning code handles |
5202 | this. the reason for SECON_HEAD is that it is needed for condition |
5203 | in trees, and this should be of the same type since it is a hook. */ |
5204 | static void |
5205 | rtl_lv_add_condition_to_bb (basic_block first_head , |
5206 | basic_block second_head ATTRIBUTE_UNUSED, |
5207 | basic_block cond_bb, void *comp_rtx) |
5208 | { |
5209 | rtx_code_label *label; |
5210 | rtx_insn *seq, *jump; |
5211 | rtx op0 = XEXP ((rtx)comp_rtx, 0); |
5212 | rtx op1 = XEXP ((rtx)comp_rtx, 1); |
5213 | enum rtx_code comp = GET_CODE ((rtx)comp_rtx); |
5214 | machine_mode mode; |
5215 | |
5216 | |
5217 | label = block_label (block: first_head); |
5218 | mode = GET_MODE (op0); |
5219 | if (mode == VOIDmode) |
5220 | mode = GET_MODE (op1); |
5221 | |
5222 | start_sequence (); |
5223 | op0 = force_operand (op0, NULL_RTX); |
5224 | op1 = force_operand (op1, NULL_RTX); |
5225 | do_compare_rtx_and_jump (op0, op1, comp, 0, mode, NULL_RTX, NULL, label, |
5226 | profile_probability::uninitialized ()); |
5227 | jump = get_last_insn (); |
5228 | JUMP_LABEL (jump) = label; |
5229 | LABEL_NUSES (label)++; |
5230 | seq = get_insns (); |
5231 | end_sequence (); |
5232 | |
5233 | /* Add the new cond, in the new head. */ |
5234 | emit_insn_after (seq, BB_END (cond_bb)); |
5235 | } |
5236 | |
5237 | |
5238 | /* Given a block B with unconditional branch at its end, get the |
5239 | store the return the branch edge and the fall-thru edge in |
5240 | BRANCH_EDGE and FALLTHRU_EDGE respectively. */ |
5241 | static void |
5242 | (basic_block b, edge *branch_edge, |
5243 | edge *fallthru_edge) |
5244 | { |
5245 | edge e = EDGE_SUCC (b, 0); |
5246 | |
5247 | if (e->flags & EDGE_FALLTHRU) |
5248 | { |
5249 | *fallthru_edge = e; |
5250 | *branch_edge = EDGE_SUCC (b, 1); |
5251 | } |
5252 | else |
5253 | { |
5254 | *branch_edge = e; |
5255 | *fallthru_edge = EDGE_SUCC (b, 1); |
5256 | } |
5257 | } |
5258 | |
5259 | void |
5260 | init_rtl_bb_info (basic_block bb) |
5261 | { |
5262 | gcc_assert (!bb->il.x.rtl); |
5263 | bb->il.x.head_ = NULL; |
5264 | bb->il.x.rtl = ggc_cleared_alloc<rtl_bb_info> (); |
5265 | } |
5266 | |
5267 | static bool |
5268 | rtl_bb_info_initialized_p (basic_block bb) |
5269 | { |
5270 | return bb->il.x.rtl; |
5271 | } |
5272 | |
5273 | /* Returns true if it is possible to remove edge E by redirecting |
5274 | it to the destination of the other edge from E->src. */ |
5275 | |
5276 | static bool |
5277 | rtl_can_remove_branch_p (const_edge e) |
5278 | { |
5279 | const_basic_block src = e->src; |
5280 | const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest; |
5281 | const rtx_insn *insn = BB_END (src); |
5282 | rtx set; |
5283 | |
5284 | /* The conditions are taken from try_redirect_by_replacing_jump. */ |
5285 | if (target == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
5286 | return false; |
5287 | |
5288 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
5289 | return false; |
5290 | |
5291 | if (BB_PARTITION (src) != BB_PARTITION (target)) |
5292 | return false; |
5293 | |
5294 | if (!onlyjump_p (insn) |
5295 | || tablejump_p (insn, NULL, NULL)) |
5296 | return false; |
5297 | |
5298 | set = single_set (insn); |
5299 | if (!set || side_effects_p (set)) |
5300 | return false; |
5301 | |
5302 | return true; |
5303 | } |
5304 | |
5305 | static basic_block |
5306 | rtl_duplicate_bb (basic_block bb, copy_bb_data *id) |
5307 | { |
5308 | bb = cfg_layout_duplicate_bb (bb, id); |
5309 | bb->aux = NULL; |
5310 | return bb; |
5311 | } |
5312 | |
5313 | /* Do book-keeping of basic block BB for the profile consistency checker. |
5314 | Store the counting in RECORD. */ |
5315 | static void |
5316 | rtl_account_profile_record (basic_block bb, struct profile_record *record) |
5317 | { |
5318 | rtx_insn *insn; |
5319 | FOR_BB_INSNS (bb, insn) |
5320 | if (INSN_P (insn)) |
5321 | { |
5322 | record->size += insn_cost (insn, false); |
5323 | if (profile_info) |
5324 | { |
5325 | if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->count.ipa ().initialized_p () |
5326 | && ENTRY_BLOCK_PTR_FOR_FN (cfun)->count.ipa ().nonzero_p () |
5327 | && bb->count.ipa ().initialized_p ()) |
5328 | record->time |
5329 | += insn_cost (insn, true) * bb->count.ipa ().to_gcov_type (); |
5330 | } |
5331 | else if (bb->count.initialized_p () |
5332 | && ENTRY_BLOCK_PTR_FOR_FN (cfun)->count.initialized_p ()) |
5333 | record->time |
5334 | += insn_cost (insn, true) |
5335 | * bb->count.to_sreal_scale |
5336 | (ENTRY_BLOCK_PTR_FOR_FN (cfun)->count).to_double (); |
5337 | else |
5338 | record->time += insn_cost (insn, true); |
5339 | } |
5340 | } |
5341 | |
5342 | /* Implementation of CFG manipulation for linearized RTL. */ |
5343 | struct cfg_hooks rtl_cfg_hooks = { |
5344 | .name: "rtl" , |
5345 | .verify_flow_info: rtl_verify_flow_info, |
5346 | .dump_bb: rtl_dump_bb, |
5347 | .dump_bb_for_graph: rtl_dump_bb_for_graph, |
5348 | .create_basic_block: rtl_create_basic_block, |
5349 | .redirect_edge_and_branch: rtl_redirect_edge_and_branch, |
5350 | .redirect_edge_and_branch_force: rtl_redirect_edge_and_branch_force, |
5351 | .can_remove_branch_p: rtl_can_remove_branch_p, |
5352 | .delete_basic_block: rtl_delete_block, |
5353 | .split_block: rtl_split_block, |
5354 | .move_block_after: rtl_move_block_after, |
5355 | .can_merge_blocks_p: rtl_can_merge_blocks, /* can_merge_blocks_p */ |
5356 | .merge_blocks: rtl_merge_blocks, |
5357 | .predict_edge: rtl_predict_edge, |
5358 | .predicted_by_p: rtl_predicted_by_p, |
5359 | .can_duplicate_block_p: cfg_layout_can_duplicate_bb_p, |
5360 | .duplicate_block: rtl_duplicate_bb, |
5361 | .split_edge: rtl_split_edge, |
5362 | .make_forwarder_block: rtl_make_forwarder_block, |
5363 | .tidy_fallthru_edge: rtl_tidy_fallthru_edge, |
5364 | .force_nonfallthru: rtl_force_nonfallthru, |
5365 | .block_ends_with_call_p: rtl_block_ends_with_call_p, |
5366 | .block_ends_with_condjump_p: rtl_block_ends_with_condjump_p, |
5367 | .flow_call_edges_add: rtl_flow_call_edges_add, |
5368 | NULL, /* execute_on_growing_pred */ |
5369 | NULL, /* execute_on_shrinking_pred */ |
5370 | NULL, /* duplicate loop for trees */ |
5371 | NULL, /* lv_add_condition_to_bb */ |
5372 | NULL, /* lv_adjust_loop_header_phi*/ |
5373 | NULL, /* extract_cond_bb_edges */ |
5374 | NULL, /* flush_pending_stmts */ |
5375 | .empty_block_p: rtl_block_empty_p, /* block_empty_p */ |
5376 | .split_block_before_cond_jump: rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */ |
5377 | .account_profile_record: rtl_account_profile_record, |
5378 | }; |
5379 | |
5380 | /* Implementation of CFG manipulation for cfg layout RTL, where |
5381 | basic block connected via fallthru edges does not have to be adjacent. |
5382 | This representation will hopefully become the default one in future |
5383 | version of the compiler. */ |
5384 | |
5385 | struct cfg_hooks cfg_layout_rtl_cfg_hooks = { |
5386 | .name: "cfglayout mode" , |
5387 | .verify_flow_info: rtl_verify_flow_info_1, |
5388 | .dump_bb: rtl_dump_bb, |
5389 | .dump_bb_for_graph: rtl_dump_bb_for_graph, |
5390 | .create_basic_block: cfg_layout_create_basic_block, |
5391 | .redirect_edge_and_branch: cfg_layout_redirect_edge_and_branch, |
5392 | .redirect_edge_and_branch_force: cfg_layout_redirect_edge_and_branch_force, |
5393 | .can_remove_branch_p: rtl_can_remove_branch_p, |
5394 | .delete_basic_block: cfg_layout_delete_block, |
5395 | .split_block: cfg_layout_split_block, |
5396 | .move_block_after: rtl_move_block_after, |
5397 | .can_merge_blocks_p: cfg_layout_can_merge_blocks_p, |
5398 | .merge_blocks: cfg_layout_merge_blocks, |
5399 | .predict_edge: rtl_predict_edge, |
5400 | .predicted_by_p: rtl_predicted_by_p, |
5401 | .can_duplicate_block_p: cfg_layout_can_duplicate_bb_p, |
5402 | .duplicate_block: cfg_layout_duplicate_bb, |
5403 | .split_edge: cfg_layout_split_edge, |
5404 | .make_forwarder_block: rtl_make_forwarder_block, |
5405 | NULL, /* tidy_fallthru_edge */ |
5406 | .force_nonfallthru: rtl_force_nonfallthru, |
5407 | .block_ends_with_call_p: rtl_block_ends_with_call_p, |
5408 | .block_ends_with_condjump_p: rtl_block_ends_with_condjump_p, |
5409 | .flow_call_edges_add: rtl_flow_call_edges_add, |
5410 | NULL, /* execute_on_growing_pred */ |
5411 | NULL, /* execute_on_shrinking_pred */ |
5412 | .cfg_hook_duplicate_loop_body_to_header_edge: duplicate_loop_body_to_header_edge, /* duplicate loop for rtl */ |
5413 | .lv_add_condition_to_bb: rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */ |
5414 | NULL, /* lv_adjust_loop_header_phi*/ |
5415 | .extract_cond_bb_edges: rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */ |
5416 | NULL, /* flush_pending_stmts */ |
5417 | .empty_block_p: rtl_block_empty_p, /* block_empty_p */ |
5418 | .split_block_before_cond_jump: rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */ |
5419 | .account_profile_record: rtl_account_profile_record, |
5420 | }; |
5421 | |
5422 | #include "gt-cfgrtl.h" |
5423 | |
5424 | #if __GNUC__ >= 10 |
5425 | # pragma GCC diagnostic pop |
5426 | #endif |
5427 | |