1 /* Calculate branch probabilities, and basic block execution counts.
2 Copyright (C) 1990-2018 Free Software Foundation, Inc.
3 Contributed by James E. Wilson, UC Berkeley/Cygnus Support;
4 based on some ideas from Dain Samples of UC Berkeley.
5 Further mangling by Bob Manson, Cygnus Support.
6
7 This file is part of GCC.
8
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 3, or (at your option) any later
12 version.
13
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
22
23 /* Generate basic block profile instrumentation and auxiliary files.
24 Profile generation is optimized, so that not all arcs in the basic
25 block graph need instrumenting. First, the BB graph is closed with
26 one entry (function start), and one exit (function exit). Any
27 ABNORMAL_EDGE cannot be instrumented (because there is no control
28 path to place the code). We close the graph by inserting fake
29 EDGE_FAKE edges to the EXIT_BLOCK, from the sources of abnormal
30 edges that do not go to the exit_block. We ignore such abnormal
31 edges. Naturally these fake edges are never directly traversed,
32 and so *cannot* be directly instrumented. Some other graph
33 massaging is done. To optimize the instrumentation we generate the
34 BB minimal span tree, only edges that are not on the span tree
35 (plus the entry point) need instrumenting. From that information
36 all other edge counts can be deduced. By construction all fake
37 edges must be on the spanning tree. We also attempt to place
38 EDGE_CRITICAL edges on the spanning tree.
39
40 The auxiliary files generated are <dumpbase>.gcno (at compile time)
41 and <dumpbase>.gcda (at run time). The format is
42 described in full in gcov-io.h. */
43
44 /* ??? Register allocation should use basic block execution counts to
45 give preference to the most commonly executed blocks. */
46
47 /* ??? Should calculate branch probabilities before instrumenting code, since
48 then we can use arc counts to help decide which arcs to instrument. */
49
50 #include "config.h"
51 #include "system.h"
52 #include "coretypes.h"
53 #include "backend.h"
54 #include "rtl.h"
55 #include "tree.h"
56 #include "gimple.h"
57 #include "cfghooks.h"
58 #include "cgraph.h"
59 #include "coverage.h"
60 #include "diagnostic-core.h"
61 #include "cfganal.h"
62 #include "value-prof.h"
63 #include "gimple-iterator.h"
64 #include "tree-cfg.h"
65 #include "dumpfile.h"
66 #include "cfgloop.h"
67
68 #include "profile.h"
69
70 /* Map from BBs/edges to gcov counters. */
71 vec<gcov_type> bb_gcov_counts;
72 hash_map<edge,gcov_type> *edge_gcov_counts;
73
74 struct bb_profile_info {
75 unsigned int count_valid : 1;
76
77 /* Number of successor and predecessor edges. */
78 gcov_type succ_count;
79 gcov_type pred_count;
80 };
81
82 #define BB_INFO(b) ((struct bb_profile_info *) (b)->aux)
83
84
85 /* Counter summary from the last set of coverage counts read. */
86
87 const struct gcov_ctr_summary *profile_info;
88
89 /* Counter working set information computed from the current counter
90 summary. Not initialized unless profile_info summary is non-NULL. */
91 static gcov_working_set_t gcov_working_sets[NUM_GCOV_WORKING_SETS];
92
93 /* Collect statistics on the performance of this pass for the entire source
94 file. */
95
96 static int total_num_blocks;
97 static int total_num_edges;
98 static int total_num_edges_ignored;
99 static int total_num_edges_instrumented;
100 static int total_num_blocks_created;
101 static int total_num_passes;
102 static int total_num_times_called;
103 static int total_hist_br_prob[20];
104 static int total_num_branches;
105
106 /* Helper function to update gcov_working_sets. */
107
add_working_set(gcov_working_set_t * set)108 void add_working_set (gcov_working_set_t *set) {
109 int i = 0;
110 for (; i < NUM_GCOV_WORKING_SETS; i++)
111 gcov_working_sets[i] = set[i];
112 }
113
114 /* Forward declarations. */
115 static void find_spanning_tree (struct edge_list *);
116
117 /* Add edge instrumentation code to the entire insn chain.
118
119 F is the first insn of the chain.
120 NUM_BLOCKS is the number of basic blocks found in F. */
121
122 static unsigned
instrument_edges(struct edge_list * el)123 instrument_edges (struct edge_list *el)
124 {
125 unsigned num_instr_edges = 0;
126 int num_edges = NUM_EDGES (el);
127 basic_block bb;
128
129 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
130 {
131 edge e;
132 edge_iterator ei;
133
134 FOR_EACH_EDGE (e, ei, bb->succs)
135 {
136 struct edge_profile_info *inf = EDGE_INFO (e);
137
138 if (!inf->ignore && !inf->on_tree)
139 {
140 gcc_assert (!(e->flags & EDGE_ABNORMAL));
141 if (dump_file)
142 fprintf (dump_file, "Edge %d to %d instrumented%s\n",
143 e->src->index, e->dest->index,
144 EDGE_CRITICAL_P (e) ? " (and split)" : "");
145 gimple_gen_edge_profiler (num_instr_edges++, e);
146 }
147 }
148 }
149
150 total_num_blocks_created += num_edges;
151 if (dump_file)
152 fprintf (dump_file, "%d edges instrumented\n", num_instr_edges);
153 return num_instr_edges;
154 }
155
156 /* Add code to measure histograms for values in list VALUES. */
157 static void
instrument_values(histogram_values values)158 instrument_values (histogram_values values)
159 {
160 unsigned i;
161
162 /* Emit code to generate the histograms before the insns. */
163
164 for (i = 0; i < values.length (); i++)
165 {
166 histogram_value hist = values[i];
167 unsigned t = COUNTER_FOR_HIST_TYPE (hist->type);
168
169 if (!coverage_counter_alloc (t, hist->n_counters))
170 continue;
171
172 switch (hist->type)
173 {
174 case HIST_TYPE_INTERVAL:
175 gimple_gen_interval_profiler (hist, t, 0);
176 break;
177
178 case HIST_TYPE_POW2:
179 gimple_gen_pow2_profiler (hist, t, 0);
180 break;
181
182 case HIST_TYPE_SINGLE_VALUE:
183 gimple_gen_one_value_profiler (hist, t, 0);
184 break;
185
186 case HIST_TYPE_INDIR_CALL:
187 case HIST_TYPE_INDIR_CALL_TOPN:
188 gimple_gen_ic_profiler (hist, t, 0);
189 break;
190
191 case HIST_TYPE_AVERAGE:
192 gimple_gen_average_profiler (hist, t, 0);
193 break;
194
195 case HIST_TYPE_IOR:
196 gimple_gen_ior_profiler (hist, t, 0);
197 break;
198
199 case HIST_TYPE_TIME_PROFILE:
200 gimple_gen_time_profiler (t, 0);
201 break;
202
203 default:
204 gcc_unreachable ();
205 }
206 }
207 }
208
209
210 /* Fill the working set information into the profile_info structure. */
211
212 void
get_working_sets(void)213 get_working_sets (void)
214 {
215 unsigned ws_ix, pctinc, pct;
216 gcov_working_set_t *ws_info;
217
218 if (!profile_info)
219 return;
220
221 compute_working_sets (profile_info, gcov_working_sets);
222
223 if (dump_file)
224 {
225 fprintf (dump_file, "Counter working sets:\n");
226 /* Multiply the percentage by 100 to avoid float. */
227 pctinc = 100 * 100 / NUM_GCOV_WORKING_SETS;
228 for (ws_ix = 0, pct = pctinc; ws_ix < NUM_GCOV_WORKING_SETS;
229 ws_ix++, pct += pctinc)
230 {
231 if (ws_ix == NUM_GCOV_WORKING_SETS - 1)
232 pct = 9990;
233 ws_info = &gcov_working_sets[ws_ix];
234 /* Print out the percentage using int arithmatic to avoid float. */
235 fprintf (dump_file, "\t\t%u.%02u%%: num counts=%u, min counter="
236 "%" PRId64 "\n",
237 pct / 100, pct - (pct / 100 * 100),
238 ws_info->num_counters,
239 (int64_t)ws_info->min_counter);
240 }
241 }
242 }
243
244 /* Given a the desired percentage of the full profile (sum_all from the
245 summary), multiplied by 10 to avoid float in PCT_TIMES_10, returns
246 the corresponding working set information. If an exact match for
247 the percentage isn't found, the closest value is used. */
248
249 gcov_working_set_t *
find_working_set(unsigned pct_times_10)250 find_working_set (unsigned pct_times_10)
251 {
252 unsigned i;
253 if (!profile_info)
254 return NULL;
255 gcc_assert (pct_times_10 <= 1000);
256 if (pct_times_10 >= 999)
257 return &gcov_working_sets[NUM_GCOV_WORKING_SETS - 1];
258 i = pct_times_10 * NUM_GCOV_WORKING_SETS / 1000;
259 if (!i)
260 return &gcov_working_sets[0];
261 return &gcov_working_sets[i - 1];
262 }
263
264 /* Computes hybrid profile for all matching entries in da_file.
265
266 CFG_CHECKSUM is the precomputed checksum for the CFG. */
267
268 static gcov_type *
get_exec_counts(unsigned cfg_checksum,unsigned lineno_checksum)269 get_exec_counts (unsigned cfg_checksum, unsigned lineno_checksum)
270 {
271 unsigned num_edges = 0;
272 basic_block bb;
273 gcov_type *counts;
274
275 /* Count the edges to be (possibly) instrumented. */
276 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
277 {
278 edge e;
279 edge_iterator ei;
280
281 FOR_EACH_EDGE (e, ei, bb->succs)
282 if (!EDGE_INFO (e)->ignore && !EDGE_INFO (e)->on_tree)
283 num_edges++;
284 }
285
286 counts = get_coverage_counts (GCOV_COUNTER_ARCS, num_edges, cfg_checksum,
287 lineno_checksum, &profile_info);
288 if (!counts)
289 return NULL;
290
291 get_working_sets ();
292
293 if (dump_file && profile_info)
294 fprintf (dump_file, "Merged %u profiles with maximal count %u.\n",
295 profile_info->runs, (unsigned) profile_info->sum_max);
296
297 return counts;
298 }
299
300
301 static bool
is_edge_inconsistent(vec<edge,va_gc> * edges)302 is_edge_inconsistent (vec<edge, va_gc> *edges)
303 {
304 edge e;
305 edge_iterator ei;
306 FOR_EACH_EDGE (e, ei, edges)
307 {
308 if (!EDGE_INFO (e)->ignore)
309 {
310 if (edge_gcov_count (e) < 0
311 && (!(e->flags & EDGE_FAKE)
312 || !block_ends_with_call_p (e->src)))
313 {
314 if (dump_file)
315 {
316 fprintf (dump_file,
317 "Edge %i->%i is inconsistent, count%" PRId64,
318 e->src->index, e->dest->index, edge_gcov_count (e));
319 dump_bb (dump_file, e->src, 0, TDF_DETAILS);
320 dump_bb (dump_file, e->dest, 0, TDF_DETAILS);
321 }
322 return true;
323 }
324 }
325 }
326 return false;
327 }
328
329 static void
correct_negative_edge_counts(void)330 correct_negative_edge_counts (void)
331 {
332 basic_block bb;
333 edge e;
334 edge_iterator ei;
335
336 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
337 {
338 FOR_EACH_EDGE (e, ei, bb->succs)
339 {
340 if (edge_gcov_count (e) < 0)
341 edge_gcov_count (e) = 0;
342 }
343 }
344 }
345
346 /* Check consistency.
347 Return true if inconsistency is found. */
348 static bool
is_inconsistent(void)349 is_inconsistent (void)
350 {
351 basic_block bb;
352 bool inconsistent = false;
353 FOR_EACH_BB_FN (bb, cfun)
354 {
355 inconsistent |= is_edge_inconsistent (bb->preds);
356 if (!dump_file && inconsistent)
357 return true;
358 inconsistent |= is_edge_inconsistent (bb->succs);
359 if (!dump_file && inconsistent)
360 return true;
361 if (bb_gcov_count (bb) < 0)
362 {
363 if (dump_file)
364 {
365 fprintf (dump_file, "BB %i count is negative "
366 "%" PRId64,
367 bb->index,
368 bb_gcov_count (bb));
369 dump_bb (dump_file, bb, 0, TDF_DETAILS);
370 }
371 inconsistent = true;
372 }
373 if (bb_gcov_count (bb) != sum_edge_counts (bb->preds))
374 {
375 if (dump_file)
376 {
377 fprintf (dump_file, "BB %i count does not match sum of incoming edges "
378 "%" PRId64" should be %" PRId64,
379 bb->index,
380 bb_gcov_count (bb),
381 sum_edge_counts (bb->preds));
382 dump_bb (dump_file, bb, 0, TDF_DETAILS);
383 }
384 inconsistent = true;
385 }
386 if (bb_gcov_count (bb) != sum_edge_counts (bb->succs) &&
387 ! (find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun)) != NULL
388 && block_ends_with_call_p (bb)))
389 {
390 if (dump_file)
391 {
392 fprintf (dump_file, "BB %i count does not match sum of outgoing edges "
393 "%" PRId64" should be %" PRId64,
394 bb->index,
395 bb_gcov_count (bb),
396 sum_edge_counts (bb->succs));
397 dump_bb (dump_file, bb, 0, TDF_DETAILS);
398 }
399 inconsistent = true;
400 }
401 if (!dump_file && inconsistent)
402 return true;
403 }
404
405 return inconsistent;
406 }
407
408 /* Set each basic block count to the sum of its outgoing edge counts */
409 static void
set_bb_counts(void)410 set_bb_counts (void)
411 {
412 basic_block bb;
413 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
414 {
415 bb_gcov_count (bb) = sum_edge_counts (bb->succs);
416 gcc_assert (bb_gcov_count (bb) >= 0);
417 }
418 }
419
420 /* Reads profile data and returns total number of edge counts read */
421 static int
read_profile_edge_counts(gcov_type * exec_counts)422 read_profile_edge_counts (gcov_type *exec_counts)
423 {
424 basic_block bb;
425 int num_edges = 0;
426 int exec_counts_pos = 0;
427 /* For each edge not on the spanning tree, set its execution count from
428 the .da file. */
429 /* The first count in the .da file is the number of times that the function
430 was entered. This is the exec_count for block zero. */
431
432 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
433 {
434 edge e;
435 edge_iterator ei;
436
437 FOR_EACH_EDGE (e, ei, bb->succs)
438 if (!EDGE_INFO (e)->ignore && !EDGE_INFO (e)->on_tree)
439 {
440 num_edges++;
441 if (exec_counts)
442 {
443 edge_gcov_count (e) = exec_counts[exec_counts_pos++];
444 if (edge_gcov_count (e) > profile_info->sum_max)
445 {
446 if (flag_profile_correction)
447 {
448 static bool informed = 0;
449 if (dump_enabled_p () && !informed)
450 dump_printf_loc (MSG_NOTE, input_location,
451 "corrupted profile info: edge count"
452 " exceeds maximal count\n");
453 informed = 1;
454 }
455 else
456 error ("corrupted profile info: edge from %i to %i exceeds maximal count",
457 bb->index, e->dest->index);
458 }
459 }
460 else
461 edge_gcov_count (e) = 0;
462
463 EDGE_INFO (e)->count_valid = 1;
464 BB_INFO (bb)->succ_count--;
465 BB_INFO (e->dest)->pred_count--;
466 if (dump_file)
467 {
468 fprintf (dump_file, "\nRead edge from %i to %i, count:",
469 bb->index, e->dest->index);
470 fprintf (dump_file, "%" PRId64,
471 (int64_t) edge_gcov_count (e));
472 }
473 }
474 }
475
476 return num_edges;
477 }
478
479
480 /* Compute the branch probabilities for the various branches.
481 Annotate them accordingly.
482
483 CFG_CHECKSUM is the precomputed checksum for the CFG. */
484
485 static void
compute_branch_probabilities(unsigned cfg_checksum,unsigned lineno_checksum)486 compute_branch_probabilities (unsigned cfg_checksum, unsigned lineno_checksum)
487 {
488 basic_block bb;
489 int i;
490 int num_edges = 0;
491 int changes;
492 int passes;
493 int hist_br_prob[20];
494 int num_branches;
495 gcov_type *exec_counts = get_exec_counts (cfg_checksum, lineno_checksum);
496 int inconsistent = 0;
497
498 /* Very simple sanity checks so we catch bugs in our profiling code. */
499 if (!profile_info)
500 {
501 if (dump_file)
502 fprintf (dump_file, "Profile info is missing; giving up\n");
503 return;
504 }
505
506 bb_gcov_counts.safe_grow_cleared (last_basic_block_for_fn (cfun));
507 edge_gcov_counts = new hash_map<edge,gcov_type>;
508
509 if (profile_info->sum_all < profile_info->sum_max)
510 {
511 error ("corrupted profile info: sum_all is smaller than sum_max");
512 exec_counts = NULL;
513 }
514
515 /* Attach extra info block to each bb. */
516 alloc_aux_for_blocks (sizeof (struct bb_profile_info));
517 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
518 {
519 edge e;
520 edge_iterator ei;
521
522 FOR_EACH_EDGE (e, ei, bb->succs)
523 if (!EDGE_INFO (e)->ignore)
524 BB_INFO (bb)->succ_count++;
525 FOR_EACH_EDGE (e, ei, bb->preds)
526 if (!EDGE_INFO (e)->ignore)
527 BB_INFO (bb)->pred_count++;
528 }
529
530 /* Avoid predicting entry on exit nodes. */
531 BB_INFO (EXIT_BLOCK_PTR_FOR_FN (cfun))->succ_count = 2;
532 BB_INFO (ENTRY_BLOCK_PTR_FOR_FN (cfun))->pred_count = 2;
533
534 num_edges = read_profile_edge_counts (exec_counts);
535
536 if (dump_file)
537 fprintf (dump_file, "\n%d edge counts read\n", num_edges);
538
539 /* For every block in the file,
540 - if every exit/entrance edge has a known count, then set the block count
541 - if the block count is known, and every exit/entrance edge but one has
542 a known execution count, then set the count of the remaining edge
543
544 As edge counts are set, decrement the succ/pred count, but don't delete
545 the edge, that way we can easily tell when all edges are known, or only
546 one edge is unknown. */
547
548 /* The order that the basic blocks are iterated through is important.
549 Since the code that finds spanning trees starts with block 0, low numbered
550 edges are put on the spanning tree in preference to high numbered edges.
551 Hence, most instrumented edges are at the end. Graph solving works much
552 faster if we propagate numbers from the end to the start.
553
554 This takes an average of slightly more than 3 passes. */
555
556 changes = 1;
557 passes = 0;
558 while (changes)
559 {
560 passes++;
561 changes = 0;
562 FOR_BB_BETWEEN (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), NULL, prev_bb)
563 {
564 struct bb_profile_info *bi = BB_INFO (bb);
565 if (! bi->count_valid)
566 {
567 if (bi->succ_count == 0)
568 {
569 edge e;
570 edge_iterator ei;
571 gcov_type total = 0;
572
573 FOR_EACH_EDGE (e, ei, bb->succs)
574 total += edge_gcov_count (e);
575 bb_gcov_count (bb) = total;
576 bi->count_valid = 1;
577 changes = 1;
578 }
579 else if (bi->pred_count == 0)
580 {
581 edge e;
582 edge_iterator ei;
583 gcov_type total = 0;
584
585 FOR_EACH_EDGE (e, ei, bb->preds)
586 total += edge_gcov_count (e);
587 bb_gcov_count (bb) = total;
588 bi->count_valid = 1;
589 changes = 1;
590 }
591 }
592 if (bi->count_valid)
593 {
594 if (bi->succ_count == 1)
595 {
596 edge e;
597 edge_iterator ei;
598 gcov_type total = 0;
599
600 /* One of the counts will be invalid, but it is zero,
601 so adding it in also doesn't hurt. */
602 FOR_EACH_EDGE (e, ei, bb->succs)
603 total += edge_gcov_count (e);
604
605 /* Search for the invalid edge, and set its count. */
606 FOR_EACH_EDGE (e, ei, bb->succs)
607 if (! EDGE_INFO (e)->count_valid && ! EDGE_INFO (e)->ignore)
608 break;
609
610 /* Calculate count for remaining edge by conservation. */
611 total = bb_gcov_count (bb) - total;
612
613 gcc_assert (e);
614 EDGE_INFO (e)->count_valid = 1;
615 edge_gcov_count (e) = total;
616 bi->succ_count--;
617
618 BB_INFO (e->dest)->pred_count--;
619 changes = 1;
620 }
621 if (bi->pred_count == 1)
622 {
623 edge e;
624 edge_iterator ei;
625 gcov_type total = 0;
626
627 /* One of the counts will be invalid, but it is zero,
628 so adding it in also doesn't hurt. */
629 FOR_EACH_EDGE (e, ei, bb->preds)
630 total += edge_gcov_count (e);
631
632 /* Search for the invalid edge, and set its count. */
633 FOR_EACH_EDGE (e, ei, bb->preds)
634 if (!EDGE_INFO (e)->count_valid && !EDGE_INFO (e)->ignore)
635 break;
636
637 /* Calculate count for remaining edge by conservation. */
638 total = bb_gcov_count (bb) - total + edge_gcov_count (e);
639
640 gcc_assert (e);
641 EDGE_INFO (e)->count_valid = 1;
642 edge_gcov_count (e) = total;
643 bi->pred_count--;
644
645 BB_INFO (e->src)->succ_count--;
646 changes = 1;
647 }
648 }
649 }
650 }
651
652 total_num_passes += passes;
653 if (dump_file)
654 fprintf (dump_file, "Graph solving took %d passes.\n\n", passes);
655
656 /* If the graph has been correctly solved, every block will have a
657 succ and pred count of zero. */
658 FOR_EACH_BB_FN (bb, cfun)
659 {
660 gcc_assert (!BB_INFO (bb)->succ_count && !BB_INFO (bb)->pred_count);
661 }
662
663 /* Check for inconsistent basic block counts */
664 inconsistent = is_inconsistent ();
665
666 if (inconsistent)
667 {
668 if (flag_profile_correction)
669 {
670 /* Inconsistency detected. Make it flow-consistent. */
671 static int informed = 0;
672 if (dump_enabled_p () && informed == 0)
673 {
674 informed = 1;
675 dump_printf_loc (MSG_NOTE, input_location,
676 "correcting inconsistent profile data\n");
677 }
678 correct_negative_edge_counts ();
679 /* Set bb counts to the sum of the outgoing edge counts */
680 set_bb_counts ();
681 if (dump_file)
682 fprintf (dump_file, "\nCalling mcf_smooth_cfg\n");
683 mcf_smooth_cfg ();
684 }
685 else
686 error ("corrupted profile info: profile data is not flow-consistent");
687 }
688
689 /* For every edge, calculate its branch probability and add a reg_note
690 to the branch insn to indicate this. */
691
692 for (i = 0; i < 20; i++)
693 hist_br_prob[i] = 0;
694 num_branches = 0;
695
696 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
697 {
698 edge e;
699 edge_iterator ei;
700
701 if (bb_gcov_count (bb) < 0)
702 {
703 error ("corrupted profile info: number of iterations for basic block %d thought to be %i",
704 bb->index, (int)bb_gcov_count (bb));
705 bb_gcov_count (bb) = 0;
706 }
707 FOR_EACH_EDGE (e, ei, bb->succs)
708 {
709 /* Function may return twice in the cased the called function is
710 setjmp or calls fork, but we can't represent this by extra
711 edge from the entry, since extra edge from the exit is
712 already present. We get negative frequency from the entry
713 point. */
714 if ((edge_gcov_count (e) < 0
715 && e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
716 || (edge_gcov_count (e) > bb_gcov_count (bb)
717 && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)))
718 {
719 if (block_ends_with_call_p (bb))
720 edge_gcov_count (e) = edge_gcov_count (e) < 0
721 ? 0 : bb_gcov_count (bb);
722 }
723 if (edge_gcov_count (e) < 0
724 || edge_gcov_count (e) > bb_gcov_count (bb))
725 {
726 error ("corrupted profile info: number of executions for edge %d-%d thought to be %i",
727 e->src->index, e->dest->index,
728 (int)edge_gcov_count (e));
729 edge_gcov_count (e) = bb_gcov_count (bb) / 2;
730 }
731 }
732 if (bb_gcov_count (bb))
733 {
734 FOR_EACH_EDGE (e, ei, bb->succs)
735 e->probability = profile_probability::probability_in_gcov_type
736 (edge_gcov_count (e), bb_gcov_count (bb));
737 if (bb->index >= NUM_FIXED_BLOCKS
738 && block_ends_with_condjump_p (bb)
739 && EDGE_COUNT (bb->succs) >= 2)
740 {
741 int prob;
742 edge e;
743 int index;
744
745 /* Find the branch edge. It is possible that we do have fake
746 edges here. */
747 FOR_EACH_EDGE (e, ei, bb->succs)
748 if (!(e->flags & (EDGE_FAKE | EDGE_FALLTHRU)))
749 break;
750
751 prob = e->probability.to_reg_br_prob_base ();
752 index = prob * 20 / REG_BR_PROB_BASE;
753
754 if (index == 20)
755 index = 19;
756 hist_br_prob[index]++;
757
758 num_branches++;
759 }
760 }
761 /* As a last resort, distribute the probabilities evenly.
762 Use simple heuristics that if there are normal edges,
763 give all abnormals frequency of 0, otherwise distribute the
764 frequency over abnormals (this is the case of noreturn
765 calls). */
766 else if (profile_status_for_fn (cfun) == PROFILE_ABSENT)
767 {
768 int total = 0;
769
770 FOR_EACH_EDGE (e, ei, bb->succs)
771 if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
772 total ++;
773 if (total)
774 {
775 FOR_EACH_EDGE (e, ei, bb->succs)
776 if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
777 e->probability
778 = profile_probability::guessed_always ().apply_scale (1, total);
779 else
780 e->probability = profile_probability::never ();
781 }
782 else
783 {
784 total += EDGE_COUNT (bb->succs);
785 FOR_EACH_EDGE (e, ei, bb->succs)
786 e->probability
787 = profile_probability::guessed_always ().apply_scale (1, total);
788 }
789 if (bb->index >= NUM_FIXED_BLOCKS
790 && block_ends_with_condjump_p (bb)
791 && EDGE_COUNT (bb->succs) >= 2)
792 num_branches++;
793 }
794 }
795
796 /* If we have real data, use them! */
797 if (bb_gcov_count (ENTRY_BLOCK_PTR_FOR_FN (cfun))
798 || !flag_guess_branch_prob)
799 FOR_ALL_BB_FN (bb, cfun)
800 bb->count = profile_count::from_gcov_type (bb_gcov_count (bb));
801 /* If function was not trained, preserve local estimates including statically
802 determined zero counts. */
803 else
804 FOR_ALL_BB_FN (bb, cfun)
805 if (!(bb->count == profile_count::zero ()))
806 bb->count = bb->count.global0 ();
807
808 bb_gcov_counts.release ();
809 delete edge_gcov_counts;
810 edge_gcov_counts = NULL;
811
812 update_max_bb_count ();
813
814 if (dump_file)
815 {
816 fprintf (dump_file, "%d branches\n", num_branches);
817 if (num_branches)
818 for (i = 0; i < 10; i++)
819 fprintf (dump_file, "%d%% branches in range %d-%d%%\n",
820 (hist_br_prob[i] + hist_br_prob[19-i]) * 100 / num_branches,
821 5 * i, 5 * i + 5);
822
823 total_num_branches += num_branches;
824 for (i = 0; i < 20; i++)
825 total_hist_br_prob[i] += hist_br_prob[i];
826
827 fputc ('\n', dump_file);
828 fputc ('\n', dump_file);
829 }
830
831 free_aux_for_blocks ();
832 }
833
834 /* Load value histograms values whose description is stored in VALUES array
835 from .gcda file.
836
837 CFG_CHECKSUM is the precomputed checksum for the CFG. */
838
839 static void
compute_value_histograms(histogram_values values,unsigned cfg_checksum,unsigned lineno_checksum)840 compute_value_histograms (histogram_values values, unsigned cfg_checksum,
841 unsigned lineno_checksum)
842 {
843 unsigned i, j, t, any;
844 unsigned n_histogram_counters[GCOV_N_VALUE_COUNTERS];
845 gcov_type *histogram_counts[GCOV_N_VALUE_COUNTERS];
846 gcov_type *act_count[GCOV_N_VALUE_COUNTERS];
847 gcov_type *aact_count;
848 struct cgraph_node *node;
849
850 for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
851 n_histogram_counters[t] = 0;
852
853 for (i = 0; i < values.length (); i++)
854 {
855 histogram_value hist = values[i];
856 n_histogram_counters[(int) hist->type] += hist->n_counters;
857 }
858
859 any = 0;
860 for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
861 {
862 if (!n_histogram_counters[t])
863 {
864 histogram_counts[t] = NULL;
865 continue;
866 }
867
868 histogram_counts[t] =
869 get_coverage_counts (COUNTER_FOR_HIST_TYPE (t),
870 n_histogram_counters[t], cfg_checksum,
871 lineno_checksum, NULL);
872 if (histogram_counts[t])
873 any = 1;
874 act_count[t] = histogram_counts[t];
875 }
876 if (!any)
877 return;
878
879 for (i = 0; i < values.length (); i++)
880 {
881 histogram_value hist = values[i];
882 gimple *stmt = hist->hvalue.stmt;
883
884 t = (int) hist->type;
885
886 aact_count = act_count[t];
887
888 if (act_count[t])
889 act_count[t] += hist->n_counters;
890
891 gimple_add_histogram_value (cfun, stmt, hist);
892 hist->hvalue.counters = XNEWVEC (gcov_type, hist->n_counters);
893 for (j = 0; j < hist->n_counters; j++)
894 if (aact_count)
895 hist->hvalue.counters[j] = aact_count[j];
896 else
897 hist->hvalue.counters[j] = 0;
898
899 /* Time profiler counter is not related to any statement,
900 so that we have to read the counter and set the value to
901 the corresponding call graph node. */
902 if (hist->type == HIST_TYPE_TIME_PROFILE)
903 {
904 node = cgraph_node::get (hist->fun->decl);
905 node->tp_first_run = hist->hvalue.counters[0];
906
907 if (dump_file)
908 fprintf (dump_file, "Read tp_first_run: %d\n", node->tp_first_run);
909 }
910 }
911
912 for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
913 free (histogram_counts[t]);
914 }
915
916 /* When passed NULL as file_name, initialize.
917 When passed something else, output the necessary commands to change
918 line to LINE and offset to FILE_NAME. */
919 static void
output_location(char const * file_name,int line,gcov_position_t * offset,basic_block bb)920 output_location (char const *file_name, int line,
921 gcov_position_t *offset, basic_block bb)
922 {
923 static char const *prev_file_name;
924 static int prev_line;
925 bool name_differs, line_differs;
926
927 if (!file_name)
928 {
929 prev_file_name = NULL;
930 prev_line = -1;
931 return;
932 }
933
934 name_differs = !prev_file_name || filename_cmp (file_name, prev_file_name);
935 line_differs = prev_line != line;
936
937 if (!*offset)
938 {
939 *offset = gcov_write_tag (GCOV_TAG_LINES);
940 gcov_write_unsigned (bb->index);
941 name_differs = line_differs = true;
942 }
943
944 /* If this is a new source file, then output the
945 file's name to the .bb file. */
946 if (name_differs)
947 {
948 prev_file_name = file_name;
949 gcov_write_unsigned (0);
950 gcov_write_filename (prev_file_name);
951 }
952 if (line_differs)
953 {
954 gcov_write_unsigned (line);
955 prev_line = line;
956 }
957 }
958
959 /* Helper for qsort so edges get sorted from highest frequency to smallest.
960 This controls the weight for minimal spanning tree algorithm */
961 static int
compare_freqs(const void * p1,const void * p2)962 compare_freqs (const void *p1, const void *p2)
963 {
964 const_edge e1 = *(const const_edge *)p1;
965 const_edge e2 = *(const const_edge *)p2;
966
967 /* Critical edges needs to be split which introduce extra control flow.
968 Make them more heavy. */
969 int m1 = EDGE_CRITICAL_P (e1) ? 2 : 1;
970 int m2 = EDGE_CRITICAL_P (e2) ? 2 : 1;
971
972 if (EDGE_FREQUENCY (e1) * m1 + m1 != EDGE_FREQUENCY (e2) * m2 + m2)
973 return EDGE_FREQUENCY (e2) * m2 + m2 - EDGE_FREQUENCY (e1) * m1 - m1;
974 /* Stabilize sort. */
975 if (e1->src->index != e2->src->index)
976 return e2->src->index - e1->src->index;
977 return e2->dest->index - e1->dest->index;
978 }
979
980 /* Only read execution count for thunks. */
981
982 void
read_thunk_profile(struct cgraph_node * node)983 read_thunk_profile (struct cgraph_node *node)
984 {
985 tree old = current_function_decl;
986 current_function_decl = node->decl;
987 gcov_type *counts = get_coverage_counts (GCOV_COUNTER_ARCS, 1, 0, 0, NULL);
988 if (counts)
989 {
990 node->callees->count = node->count
991 = profile_count::from_gcov_type (counts[0]);
992 free (counts);
993 }
994 current_function_decl = old;
995 return;
996 }
997
998
999 /* Instrument and/or analyze program behavior based on program the CFG.
1000
1001 This function creates a representation of the control flow graph (of
1002 the function being compiled) that is suitable for the instrumentation
1003 of edges and/or converting measured edge counts to counts on the
1004 complete CFG.
1005
1006 When FLAG_PROFILE_ARCS is nonzero, this function instruments the edges in
1007 the flow graph that are needed to reconstruct the dynamic behavior of the
1008 flow graph. This data is written to the gcno file for gcov.
1009
1010 When FLAG_BRANCH_PROBABILITIES is nonzero, this function reads auxiliary
1011 information from the gcda file containing edge count information from
1012 previous executions of the function being compiled. In this case, the
1013 control flow graph is annotated with actual execution counts by
1014 compute_branch_probabilities().
1015
1016 Main entry point of this file. */
1017
1018 void
branch_prob(bool thunk)1019 branch_prob (bool thunk)
1020 {
1021 basic_block bb;
1022 unsigned i;
1023 unsigned num_edges, ignored_edges;
1024 unsigned num_instrumented;
1025 struct edge_list *el;
1026 histogram_values values = histogram_values ();
1027 unsigned cfg_checksum, lineno_checksum;
1028
1029 total_num_times_called++;
1030
1031 flow_call_edges_add (NULL);
1032 add_noreturn_fake_exit_edges ();
1033
1034 if (!thunk)
1035 {
1036 /* We can't handle cyclic regions constructed using abnormal edges.
1037 To avoid these we replace every source of abnormal edge by a fake
1038 edge from entry node and every destination by fake edge to exit.
1039 This keeps graph acyclic and our calculation exact for all normal
1040 edges except for exit and entrance ones.
1041
1042 We also add fake exit edges for each call and asm statement in the
1043 basic, since it may not return. */
1044
1045 FOR_EACH_BB_FN (bb, cfun)
1046 {
1047 int need_exit_edge = 0, need_entry_edge = 0;
1048 int have_exit_edge = 0, have_entry_edge = 0;
1049 edge e;
1050 edge_iterator ei;
1051
1052 /* Functions returning multiple times are not handled by extra edges.
1053 Instead we simply allow negative counts on edges from exit to the
1054 block past call and corresponding probabilities. We can't go
1055 with the extra edges because that would result in flowgraph that
1056 needs to have fake edges outside the spanning tree. */
1057
1058 FOR_EACH_EDGE (e, ei, bb->succs)
1059 {
1060 gimple_stmt_iterator gsi;
1061 gimple *last = NULL;
1062
1063 /* It may happen that there are compiler generated statements
1064 without a locus at all. Go through the basic block from the
1065 last to the first statement looking for a locus. */
1066 for (gsi = gsi_last_nondebug_bb (bb);
1067 !gsi_end_p (gsi);
1068 gsi_prev_nondebug (&gsi))
1069 {
1070 last = gsi_stmt (gsi);
1071 if (!RESERVED_LOCATION_P (gimple_location (last)))
1072 break;
1073 }
1074
1075 /* Edge with goto locus might get wrong coverage info unless
1076 it is the only edge out of BB.
1077 Don't do that when the locuses match, so
1078 if (blah) goto something;
1079 is not computed twice. */
1080 if (last
1081 && gimple_has_location (last)
1082 && !RESERVED_LOCATION_P (e->goto_locus)
1083 && !single_succ_p (bb)
1084 && (LOCATION_FILE (e->goto_locus)
1085 != LOCATION_FILE (gimple_location (last))
1086 || (LOCATION_LINE (e->goto_locus)
1087 != LOCATION_LINE (gimple_location (last)))))
1088 {
1089 basic_block new_bb = split_edge (e);
1090 edge ne = single_succ_edge (new_bb);
1091 ne->goto_locus = e->goto_locus;
1092 }
1093 if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
1094 && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
1095 need_exit_edge = 1;
1096 if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
1097 have_exit_edge = 1;
1098 }
1099 FOR_EACH_EDGE (e, ei, bb->preds)
1100 {
1101 if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
1102 && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
1103 need_entry_edge = 1;
1104 if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun))
1105 have_entry_edge = 1;
1106 }
1107
1108 if (need_exit_edge && !have_exit_edge)
1109 {
1110 if (dump_file)
1111 fprintf (dump_file, "Adding fake exit edge to bb %i\n",
1112 bb->index);
1113 make_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE);
1114 }
1115 if (need_entry_edge && !have_entry_edge)
1116 {
1117 if (dump_file)
1118 fprintf (dump_file, "Adding fake entry edge to bb %i\n",
1119 bb->index);
1120 make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, EDGE_FAKE);
1121 /* Avoid bbs that have both fake entry edge and also some
1122 exit edge. One of those edges wouldn't be added to the
1123 spanning tree, but we can't instrument any of them. */
1124 if (have_exit_edge || need_exit_edge)
1125 {
1126 gimple_stmt_iterator gsi;
1127 gimple *first;
1128
1129 gsi = gsi_start_nondebug_after_labels_bb (bb);
1130 gcc_checking_assert (!gsi_end_p (gsi));
1131 first = gsi_stmt (gsi);
1132 /* Don't split the bbs containing __builtin_setjmp_receiver
1133 or ABNORMAL_DISPATCHER calls. These are very
1134 special and don't expect anything to be inserted before
1135 them. */
1136 if (is_gimple_call (first)
1137 && (gimple_call_builtin_p (first, BUILT_IN_SETJMP_RECEIVER)
1138 || (gimple_call_flags (first) & ECF_RETURNS_TWICE)
1139 || (gimple_call_internal_p (first)
1140 && (gimple_call_internal_fn (first)
1141 == IFN_ABNORMAL_DISPATCHER))))
1142 continue;
1143
1144 if (dump_file)
1145 fprintf (dump_file, "Splitting bb %i after labels\n",
1146 bb->index);
1147 split_block_after_labels (bb);
1148 }
1149 }
1150 }
1151 }
1152
1153 el = create_edge_list ();
1154 num_edges = NUM_EDGES (el);
1155 qsort (el->index_to_edge, num_edges, sizeof (edge), compare_freqs);
1156 alloc_aux_for_edges (sizeof (struct edge_profile_info));
1157
1158 /* The basic blocks are expected to be numbered sequentially. */
1159 compact_blocks ();
1160
1161 ignored_edges = 0;
1162 for (i = 0 ; i < num_edges ; i++)
1163 {
1164 edge e = INDEX_EDGE (el, i);
1165
1166 /* Mark edges we've replaced by fake edges above as ignored. */
1167 if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
1168 && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
1169 && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
1170 {
1171 EDGE_INFO (e)->ignore = 1;
1172 ignored_edges++;
1173 }
1174 }
1175
1176 /* Create spanning tree from basic block graph, mark each edge that is
1177 on the spanning tree. We insert as many abnormal and critical edges
1178 as possible to minimize number of edge splits necessary. */
1179
1180 if (!thunk)
1181 find_spanning_tree (el);
1182 else
1183 {
1184 edge e;
1185 edge_iterator ei;
1186 /* Keep only edge from entry block to be instrumented. */
1187 FOR_EACH_BB_FN (bb, cfun)
1188 FOR_EACH_EDGE (e, ei, bb->succs)
1189 EDGE_INFO (e)->ignore = true;
1190 }
1191
1192
1193 /* Fake edges that are not on the tree will not be instrumented, so
1194 mark them ignored. */
1195 for (num_instrumented = i = 0; i < num_edges; i++)
1196 {
1197 edge e = INDEX_EDGE (el, i);
1198 struct edge_profile_info *inf = EDGE_INFO (e);
1199
1200 if (inf->ignore || inf->on_tree)
1201 /*NOP*/;
1202 else if (e->flags & EDGE_FAKE)
1203 {
1204 inf->ignore = 1;
1205 ignored_edges++;
1206 }
1207 else
1208 num_instrumented++;
1209 }
1210
1211 total_num_blocks += n_basic_blocks_for_fn (cfun);
1212 if (dump_file)
1213 fprintf (dump_file, "%d basic blocks\n", n_basic_blocks_for_fn (cfun));
1214
1215 total_num_edges += num_edges;
1216 if (dump_file)
1217 fprintf (dump_file, "%d edges\n", num_edges);
1218
1219 total_num_edges_ignored += ignored_edges;
1220 if (dump_file)
1221 fprintf (dump_file, "%d ignored edges\n", ignored_edges);
1222
1223 total_num_edges_instrumented += num_instrumented;
1224 if (dump_file)
1225 fprintf (dump_file, "%d instrumentation edges\n", num_instrumented);
1226
1227 /* Compute two different checksums. Note that we want to compute
1228 the checksum in only once place, since it depends on the shape
1229 of the control flow which can change during
1230 various transformations. */
1231 if (thunk)
1232 {
1233 /* At stream in time we do not have CFG, so we can not do checksums. */
1234 cfg_checksum = 0;
1235 lineno_checksum = 0;
1236 }
1237 else
1238 {
1239 cfg_checksum = coverage_compute_cfg_checksum (cfun);
1240 lineno_checksum = coverage_compute_lineno_checksum ();
1241 }
1242
1243 /* Write the data from which gcov can reconstruct the basic block
1244 graph and function line numbers (the gcno file). */
1245 if (coverage_begin_function (lineno_checksum, cfg_checksum))
1246 {
1247 gcov_position_t offset;
1248
1249 /* Basic block flags */
1250 offset = gcov_write_tag (GCOV_TAG_BLOCKS);
1251 gcov_write_unsigned (n_basic_blocks_for_fn (cfun));
1252 gcov_write_length (offset);
1253
1254 /* Arcs */
1255 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
1256 EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
1257 {
1258 edge e;
1259 edge_iterator ei;
1260
1261 offset = gcov_write_tag (GCOV_TAG_ARCS);
1262 gcov_write_unsigned (bb->index);
1263
1264 FOR_EACH_EDGE (e, ei, bb->succs)
1265 {
1266 struct edge_profile_info *i = EDGE_INFO (e);
1267 if (!i->ignore)
1268 {
1269 unsigned flag_bits = 0;
1270
1271 if (i->on_tree)
1272 flag_bits |= GCOV_ARC_ON_TREE;
1273 if (e->flags & EDGE_FAKE)
1274 flag_bits |= GCOV_ARC_FAKE;
1275 if (e->flags & EDGE_FALLTHRU)
1276 flag_bits |= GCOV_ARC_FALLTHROUGH;
1277 /* On trees we don't have fallthru flags, but we can
1278 recompute them from CFG shape. */
1279 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)
1280 && e->src->next_bb == e->dest)
1281 flag_bits |= GCOV_ARC_FALLTHROUGH;
1282
1283 gcov_write_unsigned (e->dest->index);
1284 gcov_write_unsigned (flag_bits);
1285 }
1286 }
1287
1288 gcov_write_length (offset);
1289 }
1290
1291 /* Line numbers. */
1292 /* Initialize the output. */
1293 output_location (NULL, 0, NULL, NULL);
1294
1295 FOR_EACH_BB_FN (bb, cfun)
1296 {
1297 gimple_stmt_iterator gsi;
1298 gcov_position_t offset = 0;
1299
1300 if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb)
1301 {
1302 expanded_location curr_location =
1303 expand_location (DECL_SOURCE_LOCATION (current_function_decl));
1304 output_location (curr_location.file, curr_location.line,
1305 &offset, bb);
1306 }
1307
1308 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1309 {
1310 gimple *stmt = gsi_stmt (gsi);
1311 if (!RESERVED_LOCATION_P (gimple_location (stmt)))
1312 output_location (gimple_filename (stmt), gimple_lineno (stmt),
1313 &offset, bb);
1314 }
1315
1316 /* Notice GOTO expressions eliminated while constructing the CFG. */
1317 if (single_succ_p (bb)
1318 && !RESERVED_LOCATION_P (single_succ_edge (bb)->goto_locus))
1319 {
1320 expanded_location curr_location
1321 = expand_location (single_succ_edge (bb)->goto_locus);
1322 output_location (curr_location.file, curr_location.line,
1323 &offset, bb);
1324 }
1325
1326 if (offset)
1327 {
1328 /* A file of NULL indicates the end of run. */
1329 gcov_write_unsigned (0);
1330 gcov_write_string (NULL);
1331 gcov_write_length (offset);
1332 }
1333 }
1334 }
1335
1336 if (flag_profile_values)
1337 gimple_find_values_to_profile (&values);
1338
1339 if (flag_branch_probabilities)
1340 {
1341 compute_branch_probabilities (cfg_checksum, lineno_checksum);
1342 if (flag_profile_values)
1343 compute_value_histograms (values, cfg_checksum, lineno_checksum);
1344 }
1345
1346 remove_fake_edges ();
1347
1348 /* For each edge not on the spanning tree, add counting code. */
1349 if (profile_arc_flag
1350 && coverage_counter_alloc (GCOV_COUNTER_ARCS, num_instrumented))
1351 {
1352 unsigned n_instrumented;
1353
1354 gimple_init_gcov_profiler ();
1355
1356 n_instrumented = instrument_edges (el);
1357
1358 gcc_assert (n_instrumented == num_instrumented);
1359
1360 if (flag_profile_values)
1361 instrument_values (values);
1362
1363 /* Commit changes done by instrumentation. */
1364 gsi_commit_edge_inserts ();
1365 }
1366
1367 free_aux_for_edges ();
1368
1369 values.release ();
1370 free_edge_list (el);
1371 coverage_end_function (lineno_checksum, cfg_checksum);
1372 if (flag_branch_probabilities && profile_info)
1373 {
1374 struct loop *loop;
1375 if (dump_file && (dump_flags & TDF_DETAILS))
1376 report_predictor_hitrates ();
1377 profile_status_for_fn (cfun) = PROFILE_READ;
1378
1379 /* At this moment we have precise loop iteration count estimates.
1380 Record them to loop structure before the profile gets out of date. */
1381 FOR_EACH_LOOP (loop, 0)
1382 if (loop->header->count > 0)
1383 {
1384 gcov_type nit = expected_loop_iterations_unbounded (loop);
1385 widest_int bound = gcov_type_to_wide_int (nit);
1386 loop->any_estimate = false;
1387 record_niter_bound (loop, bound, true, false);
1388 }
1389 compute_function_frequency ();
1390 }
1391 }
1392
1393 /* Union find algorithm implementation for the basic blocks using
1394 aux fields. */
1395
1396 static basic_block
find_group(basic_block bb)1397 find_group (basic_block bb)
1398 {
1399 basic_block group = bb, bb1;
1400
1401 while ((basic_block) group->aux != group)
1402 group = (basic_block) group->aux;
1403
1404 /* Compress path. */
1405 while ((basic_block) bb->aux != group)
1406 {
1407 bb1 = (basic_block) bb->aux;
1408 bb->aux = (void *) group;
1409 bb = bb1;
1410 }
1411 return group;
1412 }
1413
1414 static void
union_groups(basic_block bb1,basic_block bb2)1415 union_groups (basic_block bb1, basic_block bb2)
1416 {
1417 basic_block bb1g = find_group (bb1);
1418 basic_block bb2g = find_group (bb2);
1419
1420 /* ??? I don't have a place for the rank field. OK. Lets go w/o it,
1421 this code is unlikely going to be performance problem anyway. */
1422 gcc_assert (bb1g != bb2g);
1423
1424 bb1g->aux = bb2g;
1425 }
1426
1427 /* This function searches all of the edges in the program flow graph, and puts
1428 as many bad edges as possible onto the spanning tree. Bad edges include
1429 abnormals edges, which can't be instrumented at the moment. Since it is
1430 possible for fake edges to form a cycle, we will have to develop some
1431 better way in the future. Also put critical edges to the tree, since they
1432 are more expensive to instrument. */
1433
1434 static void
find_spanning_tree(struct edge_list * el)1435 find_spanning_tree (struct edge_list *el)
1436 {
1437 int i;
1438 int num_edges = NUM_EDGES (el);
1439 basic_block bb;
1440
1441 /* We use aux field for standard union-find algorithm. */
1442 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
1443 bb->aux = bb;
1444
1445 /* Add fake edge exit to entry we can't instrument. */
1446 union_groups (EXIT_BLOCK_PTR_FOR_FN (cfun), ENTRY_BLOCK_PTR_FOR_FN (cfun));
1447
1448 /* First add all abnormal edges to the tree unless they form a cycle. Also
1449 add all edges to the exit block to avoid inserting profiling code behind
1450 setting return value from function. */
1451 for (i = 0; i < num_edges; i++)
1452 {
1453 edge e = INDEX_EDGE (el, i);
1454 if (((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_FAKE))
1455 || e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
1456 && !EDGE_INFO (e)->ignore
1457 && (find_group (e->src) != find_group (e->dest)))
1458 {
1459 if (dump_file)
1460 fprintf (dump_file, "Abnormal edge %d to %d put to tree\n",
1461 e->src->index, e->dest->index);
1462 EDGE_INFO (e)->on_tree = 1;
1463 union_groups (e->src, e->dest);
1464 }
1465 }
1466
1467 /* And now the rest. Edge list is sorted according to frequencies and
1468 thus we will produce minimal spanning tree. */
1469 for (i = 0; i < num_edges; i++)
1470 {
1471 edge e = INDEX_EDGE (el, i);
1472 if (!EDGE_INFO (e)->ignore
1473 && find_group (e->src) != find_group (e->dest))
1474 {
1475 if (dump_file)
1476 fprintf (dump_file, "Normal edge %d to %d put to tree\n",
1477 e->src->index, e->dest->index);
1478 EDGE_INFO (e)->on_tree = 1;
1479 union_groups (e->src, e->dest);
1480 }
1481 }
1482
1483 clear_aux_for_blocks ();
1484 }
1485
1486 /* Perform file-level initialization for branch-prob processing. */
1487
1488 void
init_branch_prob(void)1489 init_branch_prob (void)
1490 {
1491 int i;
1492
1493 total_num_blocks = 0;
1494 total_num_edges = 0;
1495 total_num_edges_ignored = 0;
1496 total_num_edges_instrumented = 0;
1497 total_num_blocks_created = 0;
1498 total_num_passes = 0;
1499 total_num_times_called = 0;
1500 total_num_branches = 0;
1501 for (i = 0; i < 20; i++)
1502 total_hist_br_prob[i] = 0;
1503 }
1504
1505 /* Performs file-level cleanup after branch-prob processing
1506 is completed. */
1507
1508 void
end_branch_prob(void)1509 end_branch_prob (void)
1510 {
1511 if (dump_file)
1512 {
1513 fprintf (dump_file, "\n");
1514 fprintf (dump_file, "Total number of blocks: %d\n",
1515 total_num_blocks);
1516 fprintf (dump_file, "Total number of edges: %d\n", total_num_edges);
1517 fprintf (dump_file, "Total number of ignored edges: %d\n",
1518 total_num_edges_ignored);
1519 fprintf (dump_file, "Total number of instrumented edges: %d\n",
1520 total_num_edges_instrumented);
1521 fprintf (dump_file, "Total number of blocks created: %d\n",
1522 total_num_blocks_created);
1523 fprintf (dump_file, "Total number of graph solution passes: %d\n",
1524 total_num_passes);
1525 if (total_num_times_called != 0)
1526 fprintf (dump_file, "Average number of graph solution passes: %d\n",
1527 (total_num_passes + (total_num_times_called >> 1))
1528 / total_num_times_called);
1529 fprintf (dump_file, "Total number of branches: %d\n",
1530 total_num_branches);
1531 if (total_num_branches)
1532 {
1533 int i;
1534
1535 for (i = 0; i < 10; i++)
1536 fprintf (dump_file, "%d%% branches in range %d-%d%%\n",
1537 (total_hist_br_prob[i] + total_hist_br_prob[19-i]) * 100
1538 / total_num_branches, 5*i, 5*i+5);
1539 }
1540 }
1541 }
1542