1 /* Hooks for cfg representation specific functions.
2 Copyright (C) 2003, 2004 Free Software Foundation, Inc.
3 Contributed by Sebastian Pop <s.pop@laposte.net>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
28 #include "basic-block.h"
32 /* A pointer to one of the hooks containers. */
33 static struct cfg_hooks *cfg_hooks;
35 /* Initialization of functions specific to the rtl IR. */
37 rtl_register_cfg_hooks (void)
39 cfg_hooks = &rtl_cfg_hooks;
42 /* Initialization of functions specific to the rtl IR. */
44 cfg_layout_rtl_register_cfg_hooks (void)
46 cfg_hooks = &cfg_layout_rtl_cfg_hooks;
49 /* Verify the CFG consistency.
51 Currently it does following: checks edge and basic block list correctness
52 and calls into IL dependent checking then. */
55 verify_flow_info (void)
57 size_t *edge_checksum;
58 int num_bb_notes, err = 0;
59 basic_block bb, last_bb_seen;
60 basic_block *last_visited;
62 timevar_push (TV_CFG_VERIFY);
63 last_visited = xcalloc (last_basic_block + 2, sizeof (basic_block));
64 edge_checksum = xcalloc (last_basic_block + 2, sizeof (size_t));
66 /* Check bb chain & numbers. */
67 last_bb_seen = ENTRY_BLOCK_PTR;
68 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, NULL, next_bb)
70 if (bb != EXIT_BLOCK_PTR
71 && bb != BASIC_BLOCK (bb->index))
73 error ("bb %d on wrong place", bb->index);
77 if (bb->prev_bb != last_bb_seen)
79 error ("prev_bb of %d should be %d, not %d",
80 bb->index, last_bb_seen->index, bb->prev_bb->index);
87 /* Now check the basic blocks (boundaries etc.) */
88 FOR_EACH_BB_REVERSE (bb)
95 error ("verify_flow_info: Wrong count of block %i %i",
96 bb->index, (int)bb->count);
99 if (bb->frequency < 0)
101 error ("verify_flow_info: Wrong frequency of block %i %i",
102 bb->index, bb->frequency);
105 for (e = bb->succ; e; e = e->succ_next)
107 if (last_visited [e->dest->index + 2] == bb)
109 error ("verify_flow_info: Duplicate edge %i->%i",
110 e->src->index, e->dest->index);
113 if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
115 error ("verify_flow_info: Wrong probability of edge %i->%i %i",
116 e->src->index, e->dest->index, e->probability);
121 error ("verify_flow_info: Wrong count of edge %i->%i %i",
122 e->src->index, e->dest->index, (int)e->count);
126 last_visited [e->dest->index + 2] = bb;
128 if (e->flags & EDGE_FALLTHRU)
133 error ("verify_flow_info: Basic block %d succ edge is corrupted",
135 fprintf (stderr, "Predecessor: ");
136 dump_edge_info (stderr, e, 0);
137 fprintf (stderr, "\nSuccessor: ");
138 dump_edge_info (stderr, e, 1);
139 fprintf (stderr, "\n");
143 edge_checksum[e->dest->index + 2] += (size_t) e;
147 error ("Wrong amount of branch edges after unconditional jump %i", bb->index);
151 for (e = bb->pred; e; e = e->pred_next)
155 error ("basic block %d pred edge is corrupted", bb->index);
156 fputs ("Predecessor: ", stderr);
157 dump_edge_info (stderr, e, 0);
158 fputs ("\nSuccessor: ", stderr);
159 dump_edge_info (stderr, e, 1);
160 fputc ('\n', stderr);
163 edge_checksum[e->dest->index + 2] -= (size_t) e;
167 /* Complete edge checksumming for ENTRY and EXIT. */
171 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
172 edge_checksum[e->dest->index + 2] += (size_t) e;
174 for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next)
175 edge_checksum[e->dest->index + 2] -= (size_t) e;
178 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
179 if (edge_checksum[bb->index + 2])
181 error ("basic block %i edge lists are corrupted", bb->index);
186 last_bb_seen = ENTRY_BLOCK_PTR;
190 free (edge_checksum);
192 if (cfg_hooks->verify_flow_info)
193 err |= cfg_hooks->verify_flow_info ();
195 internal_error ("verify_flow_info failed");
196 timevar_pop (TV_CFG_VERIFY);
199 /* Print out one basic block. This function takes care of the purely
200 graph related information. The cfg hook for the active representation
201 should dump representation-specific information. */
204 dump_bb (basic_block bb, FILE *outf, int indent)
209 s_indent = (char *) alloca ((size_t) indent + 1);
210 memset ((void *) s_indent, ' ', (size_t) indent);
211 s_indent[indent] = '\0';
213 fprintf (outf, ";;%s basic block %d, loop depth %d, count ",
214 s_indent, bb->index, bb->loop_depth);
215 fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
218 fprintf (outf, ";;%s prev block ", s_indent);
220 fprintf (outf, "%d, ", bb->prev_bb->index);
222 fprintf (outf, "(nil), ");
223 fprintf (outf, "next block ");
225 fprintf (outf, "%d", bb->next_bb->index);
227 fprintf (outf, "(nil)");
230 fprintf (outf, ";;%s pred: ", s_indent);
231 for (e = bb->pred; e; e = e->pred_next)
232 dump_edge_info (outf, e, 0);
235 fprintf (outf, ";;%s succ: ", s_indent);
236 for (e = bb->succ; e; e = e->succ_next)
237 dump_edge_info (outf, e, 1);
240 if (cfg_hooks->dump_bb)
241 cfg_hooks->dump_bb (bb, outf, indent);
244 /* Redirect edge E to the given basic block DEST and update underlying program
245 representation. Returns edge representing redirected branch (that may not
246 be equivalent to E in the case of duplicate edges being removed) or NULL
247 if edge is not easily redirectable for whatever reason. */
250 redirect_edge_and_branch (edge e, basic_block dest)
254 if (!cfg_hooks->redirect_edge_and_branch)
255 internal_error ("%s does not support redirect_edge_and_branch.",
258 ret = cfg_hooks->redirect_edge_and_branch (e, dest);
263 /* Redirect the edge E to basic block DEST even if it requires creating
264 of a new basic block; then it returns the newly created basic block.
265 Aborts when redirection is impossible. */
268 redirect_edge_and_branch_force (edge e, basic_block dest)
272 if (!cfg_hooks->redirect_edge_and_branch_force)
273 internal_error ("%s does not support redirect_edge_and_branch_force.",
276 ret = cfg_hooks->redirect_edge_and_branch_force (e, dest);
281 /* Splits basic block BB after the specified instruction I (but at least after
282 the labels). If I is NULL, splits just after labels. The newly created edge
283 is returned. The new basic block is created just after the old one. */
286 split_block (basic_block bb, void *i)
291 if (!cfg_hooks->split_block)
292 internal_error ("%s does not support split_block.", cfg_hooks->name);
294 new_bb = cfg_hooks->split_block (bb, i);
298 new_bb->count = bb->count;
299 new_bb->frequency = bb->frequency;
300 new_bb->loop_depth = bb->loop_depth;
302 if (dom_computed[CDI_DOMINATORS] >= DOM_CONS_OK)
304 redirect_immediate_dominators (CDI_DOMINATORS, bb, new_bb);
305 set_immediate_dominator (CDI_DOMINATORS, new_bb, bb);
308 e = make_edge (bb, new_bb, EDGE_FALLTHRU);
309 e->probability = REG_BR_PROB_BASE;
310 e->count = bb->count;
315 /* Splits block BB just after labels. The newly created edge is returned. */
318 split_block_after_labels (basic_block bb)
320 return split_block (bb, NULL);
323 /* Moves block BB immediatelly after block AFTER. Returns false if the
324 movement was impossible. */
327 move_block_after (basic_block bb, basic_block after)
331 if (!cfg_hooks->move_block_after)
332 internal_error ("%s does not support move_block_after.", cfg_hooks->name);
334 ret = cfg_hooks->move_block_after (bb, after);
339 /* Deletes the basic block BB. */
342 delete_basic_block (basic_block bb)
344 if (!cfg_hooks->delete_basic_block)
345 internal_error ("%s does not support delete_basic_block.", cfg_hooks->name);
347 cfg_hooks->delete_basic_block (bb);
349 /* Remove the edges into and out of this block. Note that there may
350 indeed be edges in, if we are removing an unreachable loop. */
351 while (bb->pred != NULL)
352 remove_edge (bb->pred);
353 while (bb->succ != NULL)
354 remove_edge (bb->succ);
359 if (dom_computed[CDI_DOMINATORS])
360 delete_from_dominance_info (CDI_DOMINATORS, bb);
361 if (dom_computed[CDI_POST_DOMINATORS])
362 delete_from_dominance_info (CDI_POST_DOMINATORS, bb);
364 /* Remove the basic block from the array. */
368 /* Splits edge E and returns the newly created basic block. */
374 gcov_type count = e->count;
375 int freq = EDGE_FREQUENCY (e);
377 if (!cfg_hooks->split_edge)
378 internal_error ("%s does not support split_edge.", cfg_hooks->name);
380 ret = cfg_hooks->split_edge (e);
382 ret->frequency = freq;
383 ret->succ->probability = REG_BR_PROB_BASE;
384 ret->succ->count = count;
386 if (dom_computed[CDI_DOMINATORS])
387 set_immediate_dominator (CDI_DOMINATORS, ret, ret->pred->src);
389 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
390 set_immediate_dominator (CDI_DOMINATORS, ret->succ->dest,
391 recount_dominator (CDI_DOMINATORS,
397 /* Creates a new basic block just after the basic block AFTER.
398 HEAD and END are the first and the last statement belonging
399 to the block. If both are NULL, an empty block is created. */
402 create_basic_block (void *head, void *end, basic_block after)
406 if (!cfg_hooks->create_basic_block)
407 internal_error ("%s does not support create_basic_block.", cfg_hooks->name);
409 ret = cfg_hooks->create_basic_block (head, end, after);
411 if (dom_computed[CDI_DOMINATORS])
412 add_to_dominance_info (CDI_DOMINATORS, ret);
413 if (dom_computed[CDI_POST_DOMINATORS])
414 add_to_dominance_info (CDI_POST_DOMINATORS, ret);
419 /* Creates an empty basic block just after basic block AFTER. */
422 create_empty_bb (basic_block after)
424 return create_basic_block (NULL, NULL, after);
427 /* Checks whether we may merge blocks BB1 and BB2. */
430 can_merge_blocks_p (basic_block bb1, basic_block bb2)
434 if (!cfg_hooks->can_merge_blocks_p)
435 internal_error ("%s does not support can_merge_blocks_p.", cfg_hooks->name);
437 ret = cfg_hooks->can_merge_blocks_p (bb1, bb2);
442 /* Merges basic block B into basic block A. */
445 merge_blocks (basic_block a, basic_block b)
449 if (!cfg_hooks->merge_blocks)
450 internal_error ("%s does not support merge_blocks.", cfg_hooks->name);
452 cfg_hooks->merge_blocks (a, b);
454 /* Normally there should only be one successor of A and that is B, but
455 partway though the merge of blocks for conditional_execution we'll
456 be merging a TEST block with THEN and ELSE successors. Free the
457 whole lot of them and hope the caller knows what they're doing. */
459 remove_edge (a->succ);
461 /* Adjust the edges out of B for the new owner. */
462 for (e = b->succ; e; e = e->succ_next)
465 a->flags |= b->flags;
467 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
468 b->pred = b->succ = NULL;
469 a->global_live_at_end = b->global_live_at_end;
471 if (dom_computed[CDI_DOMINATORS])
472 redirect_immediate_dominators (CDI_DOMINATORS, b, a);
474 if (dom_computed[CDI_DOMINATORS])
475 delete_from_dominance_info (CDI_DOMINATORS, b);
476 if (dom_computed[CDI_POST_DOMINATORS])
477 delete_from_dominance_info (CDI_POST_DOMINATORS, b);
482 /* Split BB into entry part and the rest (the rest is the newly created block).
483 Redirect those edges for that REDIRECT_EDGE_P returns true to the entry
484 part. Returns the edge connecting the entry part to the rest. */
487 make_forwarder_block (basic_block bb, bool (*redirect_edge_p) (edge),
488 void (*new_bb_cbk) (basic_block))
490 edge e, next_e, fallthru;
491 basic_block dummy, jump;
493 if (!cfg_hooks->make_forwarder_block)
494 internal_error ("%s does not support make_forwarder_block.",
497 fallthru = split_block_after_labels (bb);
498 dummy = fallthru->src;
501 /* Redirect back edges we want to keep. */
502 for (e = dummy->pred; e; e = next_e)
504 next_e = e->pred_next;
505 if (redirect_edge_p (e))
508 dummy->frequency -= EDGE_FREQUENCY (e);
509 dummy->count -= e->count;
510 if (dummy->frequency < 0)
511 dummy->frequency = 0;
512 if (dummy->count < 0)
515 jump = redirect_edge_and_branch_force (e, bb);
520 if (dom_computed[CDI_DOMINATORS] >= DOM_CONS_OK)
522 basic_block doms_to_fix[2];
524 doms_to_fix[0] = dummy;
526 iterate_fix_dominators (CDI_DOMINATORS, doms_to_fix, 2);
529 cfg_hooks->make_forwarder_block (fallthru);
535 tidy_fallthru_edge (edge e)
537 if (cfg_hooks->tidy_fallthru_edge)
538 cfg_hooks->tidy_fallthru_edge (e);
541 /* Fix up edges that now fall through, or rather should now fall through
542 but previously required a jump around now deleted blocks. Simplify
543 the search by only examining blocks numerically adjacent, since this
544 is how find_basic_blocks created them. */
547 tidy_fallthru_edges (void)
551 if (!cfg_hooks->tidy_fallthru_edge)
554 if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
557 FOR_BB_BETWEEN (b, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR->prev_bb, next_bb)
563 /* We care about simple conditional or unconditional jumps with
566 If we had a conditional branch to the next instruction when
567 find_basic_blocks was called, then there will only be one
568 out edge for the block which ended with the conditional
569 branch (since we do not create duplicate edges).
571 Furthermore, the edge will be marked as a fallthru because we
572 merge the flags for the duplicate edges. So we do not want to
573 check that the edge is not a FALLTHRU edge. */
575 if ((s = b->succ) != NULL
576 && ! (s->flags & EDGE_COMPLEX)
577 && s->succ_next == NULL
579 tidy_fallthru_edge (s);