1 /* Calculate branch probabilities, and basic block execution counts.
2 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 Contributed by James E. Wilson, UC Berkeley/Cygnus Support;
5 based on some ideas from Dain Samples of UC Berkeley.
6 Further mangling by Bob Manson, Cygnus Support.
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify it under
11 the terms of the GNU General Public License as published by the Free
12 Software Foundation; either version 2, or (at your option) any later
15 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING. If not, write to the Free
22 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
25 /* Generate basic block profile instrumentation and auxiliary files.
26 Profile generation is optimized, so that not all arcs in the basic
27 block graph need instrumenting. First, the BB graph is closed with
28 one entry (function start), and one exit (function exit). Any
29 ABNORMAL_EDGE cannot be instrumented (because there is no control
30 path to place the code). We close the graph by inserting fake
31 EDGE_FAKE edges to the EXIT_BLOCK, from the sources of abnormal
32 edges that do not go to the exit_block. We ignore such abnormal
33 edges. Naturally these fake edges are never directly traversed,
34 and so *cannot* be directly instrumented. Some other graph
35 massaging is done. To optimize the instrumentation we generate the
36 BB minimal span tree, only edges that are not on the span tree
37 (plus the entry point) need instrumenting. From that information
38 all other edge counts can be deduced. By construction all fake
39 edges must be on the spanning tree. We also attempt to place
40 EDGE_CRITICAL edges on the spanning tree.
42 The auxiliary files generated are <dumpbase>.gcno (at compile time)
43 and <dumpbase>.gcda (at run time). The format is
44 described in full in gcov-io.h. */
46 /* ??? Register allocation should use basic block execution counts to
47 give preference to the most commonly executed blocks. */
49 /* ??? Should calculate branch probabilities before instrumenting code, since
50 then we can use arc counts to help decide which arcs to instrument. */
54 #include "coretypes.h"
64 #include "value-prof.h"
67 #include "tree-flow.h"
70 #include "tree-pass.h"
72 /* Hooks for profiling. */
73 static struct profile_hooks
* profile_hooks
;
75 /* Additional information about the edges we need. */
77 unsigned int count_valid
: 1;
79 /* Is on the spanning tree. */
80 unsigned int on_tree
: 1;
82 /* Pretend this edge does not exist (it is abnormal and we've
83 inserted a fake to compensate). */
84 unsigned int ignore
: 1;
88 unsigned int count_valid
: 1;
90 /* Number of successor and predecessor edges. */
95 #define EDGE_INFO(e) ((struct edge_info *) (e)->aux)
96 #define BB_INFO(b) ((struct bb_info *) (b)->aux)
98 /* Counter summary from the last set of coverage counts read. */
100 const struct gcov_ctr_summary
*profile_info
;
102 /* Collect statistics on the performance of this pass for the entire source
105 static int total_num_blocks
;
106 static int total_num_edges
;
107 static int total_num_edges_ignored
;
108 static int total_num_edges_instrumented
;
109 static int total_num_blocks_created
;
110 static int total_num_passes
;
111 static int total_num_times_called
;
112 static int total_hist_br_prob
[20];
113 static int total_num_never_executed
;
114 static int total_num_branches
;
116 /* Forward declarations. */
117 static void find_spanning_tree (struct edge_list
*);
118 static unsigned instrument_edges (struct edge_list
*);
119 static void instrument_values (histogram_values
);
120 static void compute_branch_probabilities (void);
121 static void compute_value_histograms (histogram_values
);
122 static gcov_type
* get_exec_counts (void);
123 static basic_block
find_group (basic_block
);
124 static void union_groups (basic_block
, basic_block
);
127 /* Add edge instrumentation code to the entire insn chain.
129 F is the first insn of the chain.
130 NUM_BLOCKS is the number of basic blocks found in F. */
133 instrument_edges (struct edge_list
*el
)
135 unsigned num_instr_edges
= 0;
136 int num_edges
= NUM_EDGES (el
);
139 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
144 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
146 struct edge_info
*inf
= EDGE_INFO (e
);
148 if (!inf
->ignore
&& !inf
->on_tree
)
150 gcc_assert (!(e
->flags
& EDGE_ABNORMAL
));
152 fprintf (dump_file
, "Edge %d to %d instrumented%s\n",
153 e
->src
->index
, e
->dest
->index
,
154 EDGE_CRITICAL_P (e
) ? " (and split)" : "");
155 (profile_hooks
->gen_edge_profiler
) (num_instr_edges
++, e
);
160 total_num_blocks_created
+= num_edges
;
162 fprintf (dump_file
, "%d edges instrumented\n", num_instr_edges
);
163 return num_instr_edges
;
166 /* Add code to measure histograms for values in list VALUES. */
168 instrument_values (histogram_values values
)
172 /* Emit code to generate the histograms before the insns. */
174 for (i
= 0; i
< VEC_length (histogram_value
, values
); i
++)
176 histogram_value hist
= VEC_index (histogram_value
, values
, i
);
179 case HIST_TYPE_INTERVAL
:
180 t
= GCOV_COUNTER_V_INTERVAL
;
184 t
= GCOV_COUNTER_V_POW2
;
187 case HIST_TYPE_SINGLE_VALUE
:
188 t
= GCOV_COUNTER_V_SINGLE
;
191 case HIST_TYPE_CONST_DELTA
:
192 t
= GCOV_COUNTER_V_DELTA
;
198 if (!coverage_counter_alloc (t
, hist
->n_counters
))
203 case HIST_TYPE_INTERVAL
:
204 (profile_hooks
->gen_interval_profiler
) (hist
, t
, 0);
208 (profile_hooks
->gen_pow2_profiler
) (hist
, t
, 0);
211 case HIST_TYPE_SINGLE_VALUE
:
212 (profile_hooks
->gen_one_value_profiler
) (hist
, t
, 0);
215 case HIST_TYPE_CONST_DELTA
:
216 (profile_hooks
->gen_const_delta_profiler
) (hist
, t
, 0);
223 VEC_free (histogram_value
, heap
, values
);
227 /* Computes hybrid profile for all matching entries in da_file. */
230 get_exec_counts (void)
232 unsigned num_edges
= 0;
236 /* Count the edges to be (possibly) instrumented. */
237 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
242 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
243 if (!EDGE_INFO (e
)->ignore
&& !EDGE_INFO (e
)->on_tree
)
247 counts
= get_coverage_counts (GCOV_COUNTER_ARCS
, num_edges
, &profile_info
);
251 if (dump_file
&& profile_info
)
252 fprintf(dump_file
, "Merged %u profiles with maximal count %u.\n",
253 profile_info
->runs
, (unsigned) profile_info
->sum_max
);
259 /* Compute the branch probabilities for the various branches.
260 Annotate them accordingly. */
263 compute_branch_probabilities (void)
270 int hist_br_prob
[20];
271 int num_never_executed
;
273 gcov_type
*exec_counts
= get_exec_counts ();
274 int exec_counts_pos
= 0;
276 /* Very simple sanity checks so we catch bugs in our profiling code. */
279 if (profile_info
->run_max
* profile_info
->runs
< profile_info
->sum_max
)
281 error ("corrupted profile info: run_max * runs < sum_max");
285 if (profile_info
->sum_all
< profile_info
->sum_max
)
287 error ("corrupted profile info: sum_all is smaller than sum_max");
292 /* Attach extra info block to each bb. */
294 alloc_aux_for_blocks (sizeof (struct bb_info
));
295 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
300 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
301 if (!EDGE_INFO (e
)->ignore
)
302 BB_INFO (bb
)->succ_count
++;
303 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
304 if (!EDGE_INFO (e
)->ignore
)
305 BB_INFO (bb
)->pred_count
++;
308 /* Avoid predicting entry on exit nodes. */
309 BB_INFO (EXIT_BLOCK_PTR
)->succ_count
= 2;
310 BB_INFO (ENTRY_BLOCK_PTR
)->pred_count
= 2;
312 /* For each edge not on the spanning tree, set its execution count from
315 /* The first count in the .da file is the number of times that the function
316 was entered. This is the exec_count for block zero. */
318 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
323 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
324 if (!EDGE_INFO (e
)->ignore
&& !EDGE_INFO (e
)->on_tree
)
329 e
->count
= exec_counts
[exec_counts_pos
++];
330 if (e
->count
> profile_info
->sum_max
)
332 error ("corrupted profile info: edge from %i to %i exceeds maximal count",
333 bb
->index
, e
->dest
->index
);
339 EDGE_INFO (e
)->count_valid
= 1;
340 BB_INFO (bb
)->succ_count
--;
341 BB_INFO (e
->dest
)->pred_count
--;
344 fprintf (dump_file
, "\nRead edge from %i to %i, count:",
345 bb
->index
, e
->dest
->index
);
346 fprintf (dump_file
, HOST_WIDEST_INT_PRINT_DEC
,
347 (HOST_WIDEST_INT
) e
->count
);
353 fprintf (dump_file
, "\n%d edge counts read\n", num_edges
);
355 /* For every block in the file,
356 - if every exit/entrance edge has a known count, then set the block count
357 - if the block count is known, and every exit/entrance edge but one has
358 a known execution count, then set the count of the remaining edge
360 As edge counts are set, decrement the succ/pred count, but don't delete
361 the edge, that way we can easily tell when all edges are known, or only
362 one edge is unknown. */
364 /* The order that the basic blocks are iterated through is important.
365 Since the code that finds spanning trees starts with block 0, low numbered
366 edges are put on the spanning tree in preference to high numbered edges.
367 Hence, most instrumented edges are at the end. Graph solving works much
368 faster if we propagate numbers from the end to the start.
370 This takes an average of slightly more than 3 passes. */
378 FOR_BB_BETWEEN (bb
, EXIT_BLOCK_PTR
, NULL
, prev_bb
)
380 struct bb_info
*bi
= BB_INFO (bb
);
381 if (! bi
->count_valid
)
383 if (bi
->succ_count
== 0)
389 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
395 else if (bi
->pred_count
== 0)
401 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
410 if (bi
->succ_count
== 1)
416 /* One of the counts will be invalid, but it is zero,
417 so adding it in also doesn't hurt. */
418 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
421 /* Seedgeh for the invalid edge, and set its count. */
422 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
423 if (! EDGE_INFO (e
)->count_valid
&& ! EDGE_INFO (e
)->ignore
)
426 /* Calculate count for remaining edge by conservation. */
427 total
= bb
->count
- total
;
430 EDGE_INFO (e
)->count_valid
= 1;
434 BB_INFO (e
->dest
)->pred_count
--;
437 if (bi
->pred_count
== 1)
443 /* One of the counts will be invalid, but it is zero,
444 so adding it in also doesn't hurt. */
445 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
448 /* Search for the invalid edge, and set its count. */
449 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
450 if (!EDGE_INFO (e
)->count_valid
&& !EDGE_INFO (e
)->ignore
)
453 /* Calculate count for remaining edge by conservation. */
454 total
= bb
->count
- total
+ e
->count
;
457 EDGE_INFO (e
)->count_valid
= 1;
461 BB_INFO (e
->src
)->succ_count
--;
468 dump_flow_info (dump_file
, dump_flags
);
470 total_num_passes
+= passes
;
472 fprintf (dump_file
, "Graph solving took %d passes.\n\n", passes
);
474 /* If the graph has been correctly solved, every block will have a
475 succ and pred count of zero. */
478 gcc_assert (!BB_INFO (bb
)->succ_count
&& !BB_INFO (bb
)->pred_count
);
481 /* For every edge, calculate its branch probability and add a reg_note
482 to the branch insn to indicate this. */
484 for (i
= 0; i
< 20; i
++)
486 num_never_executed
= 0;
489 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
497 error ("corrupted profile info: number of iterations for basic block %d thought to be %i",
498 bb
->index
, (int)bb
->count
);
501 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
503 /* Function may return twice in the cased the called function is
504 setjmp or calls fork, but we can't represent this by extra
505 edge from the entry, since extra edge from the exit is
506 already present. We get negative frequency from the entry
509 && e
->dest
== EXIT_BLOCK_PTR
)
510 || (e
->count
> bb
->count
511 && e
->dest
!= EXIT_BLOCK_PTR
))
513 if (block_ends_with_call_p (bb
))
514 e
->count
= e
->count
< 0 ? 0 : bb
->count
;
516 if (e
->count
< 0 || e
->count
> bb
->count
)
518 error ("corrupted profile info: number of executions for edge %d-%d thought to be %i",
519 e
->src
->index
, e
->dest
->index
,
521 e
->count
= bb
->count
/ 2;
526 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
527 e
->probability
= (e
->count
* REG_BR_PROB_BASE
+ bb
->count
/ 2) / bb
->count
;
528 if (bb
->index
>= NUM_FIXED_BLOCKS
529 && block_ends_with_condjump_p (bb
)
530 && EDGE_COUNT (bb
->succs
) >= 2)
536 /* Find the branch edge. It is possible that we do have fake
538 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
539 if (!(e
->flags
& (EDGE_FAKE
| EDGE_FALLTHRU
)))
542 prob
= e
->probability
;
543 index
= prob
* 20 / REG_BR_PROB_BASE
;
547 hist_br_prob
[index
]++;
549 /* Do this for RTL only. */
552 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, 0);
553 /* There may be already note put by some other pass, such
554 as builtin_expect expander. */
556 XEXP (note
, 0) = GEN_INT (prob
);
558 REG_NOTES (BB_END (bb
))
559 = gen_rtx_EXPR_LIST (REG_BR_PROB
, GEN_INT (prob
),
560 REG_NOTES (BB_END (bb
)));
565 /* Otherwise try to preserve the existing REG_BR_PROB probabilities
566 tree based profile guessing put into code. BB can be the
567 ENTRY_BLOCK, and it can have multiple (fake) successors in
568 EH cases, but it still has no code; don't crash in this case. */
569 else if (profile_status
== PROFILE_ABSENT
571 && EDGE_COUNT (bb
->succs
) > 1
573 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, 0)))
575 int prob
= INTVAL (XEXP (note
, 0));
577 BRANCH_EDGE (bb
)->probability
= prob
;
578 FALLTHRU_EDGE (bb
)->probability
= REG_BR_PROB_BASE
- prob
;
580 /* As a last resort, distribute the probabilities evenly.
581 Use simple heuristics that if there are normal edges,
582 give all abnormals frequency of 0, otherwise distribute the
583 frequency over abnormals (this is the case of noreturn
585 else if (profile_status
== PROFILE_ABSENT
)
589 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
590 if (!(e
->flags
& (EDGE_COMPLEX
| EDGE_FAKE
)))
594 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
595 if (!(e
->flags
& (EDGE_COMPLEX
| EDGE_FAKE
)))
596 e
->probability
= REG_BR_PROB_BASE
/ total
;
602 total
+= EDGE_COUNT (bb
->succs
);
603 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
604 e
->probability
= REG_BR_PROB_BASE
/ total
;
606 if (bb
->index
>= NUM_FIXED_BLOCKS
607 && block_ends_with_condjump_p (bb
)
608 && EDGE_COUNT (bb
->succs
) >= 2)
609 num_branches
++, num_never_executed
;
616 fprintf (dump_file
, "%d branches\n", num_branches
);
617 fprintf (dump_file
, "%d branches never executed\n",
620 for (i
= 0; i
< 10; i
++)
621 fprintf (dump_file
, "%d%% branches in range %d-%d%%\n",
622 (hist_br_prob
[i
] + hist_br_prob
[19-i
]) * 100 / num_branches
,
625 total_num_branches
+= num_branches
;
626 total_num_never_executed
+= num_never_executed
;
627 for (i
= 0; i
< 20; i
++)
628 total_hist_br_prob
[i
] += hist_br_prob
[i
];
630 fputc ('\n', dump_file
);
631 fputc ('\n', dump_file
);
634 free_aux_for_blocks ();
637 /* Load value histograms values whose description is stored in VALUES array
641 compute_value_histograms (histogram_values values
)
643 unsigned i
, j
, t
, any
;
644 unsigned n_histogram_counters
[GCOV_N_VALUE_COUNTERS
];
645 gcov_type
*histogram_counts
[GCOV_N_VALUE_COUNTERS
];
646 gcov_type
*act_count
[GCOV_N_VALUE_COUNTERS
];
647 gcov_type
*aact_count
;
649 for (t
= 0; t
< GCOV_N_VALUE_COUNTERS
; t
++)
650 n_histogram_counters
[t
] = 0;
652 for (i
= 0; i
< VEC_length (histogram_value
, values
); i
++)
654 histogram_value hist
= VEC_index (histogram_value
, values
, i
);
655 n_histogram_counters
[(int) hist
->type
] += hist
->n_counters
;
659 for (t
= 0; t
< GCOV_N_VALUE_COUNTERS
; t
++)
661 if (!n_histogram_counters
[t
])
663 histogram_counts
[t
] = NULL
;
667 histogram_counts
[t
] =
668 get_coverage_counts (COUNTER_FOR_HIST_TYPE (t
),
669 n_histogram_counters
[t
], NULL
);
670 if (histogram_counts
[t
])
672 act_count
[t
] = histogram_counts
[t
];
677 for (i
= 0; i
< VEC_length (histogram_value
, values
); i
++)
679 histogram_value hist
= VEC_index (histogram_value
, values
, i
);
680 tree stmt
= hist
->hvalue
.stmt
;
681 stmt_ann_t ann
= get_stmt_ann (stmt
);
683 t
= (int) hist
->type
;
685 aact_count
= act_count
[t
];
686 act_count
[t
] += hist
->n_counters
;
688 hist
->hvalue
.next
= ann
->histograms
;
689 ann
->histograms
= hist
;
690 hist
->hvalue
.counters
= XNEWVEC (gcov_type
, hist
->n_counters
);
691 for (j
= 0; j
< hist
->n_counters
; j
++)
692 hist
->hvalue
.counters
[j
] = aact_count
[j
];
695 for (t
= 0; t
< GCOV_N_VALUE_COUNTERS
; t
++)
696 if (histogram_counts
[t
])
697 free (histogram_counts
[t
]);
700 /* The entry basic block will be moved around so that it has index=1,
701 there is nothing at index 0 and the exit is at n_basic_block. */
702 #define BB_TO_GCOV_INDEX(bb) ((bb)->index - 1)
703 /* When passed NULL as file_name, initialize.
704 When passed something else, output the necessary commands to change
705 line to LINE and offset to FILE_NAME. */
707 output_location (char const *file_name
, int line
,
708 gcov_position_t
*offset
, basic_block bb
)
710 static char const *prev_file_name
;
711 static int prev_line
;
712 bool name_differs
, line_differs
;
716 prev_file_name
= NULL
;
721 name_differs
= !prev_file_name
|| strcmp (file_name
, prev_file_name
);
722 line_differs
= prev_line
!= line
;
724 if (name_differs
|| line_differs
)
728 *offset
= gcov_write_tag (GCOV_TAG_LINES
);
729 gcov_write_unsigned (BB_TO_GCOV_INDEX (bb
));
730 name_differs
= line_differs
=true;
733 /* If this is a new source file, then output the
734 file's name to the .bb file. */
737 prev_file_name
= file_name
;
738 gcov_write_unsigned (0);
739 gcov_write_string (prev_file_name
);
743 gcov_write_unsigned (line
);
749 /* Instrument and/or analyze program behavior based on program flow graph.
750 In either case, this function builds a flow graph for the function being
751 compiled. The flow graph is stored in BB_GRAPH.
753 When FLAG_PROFILE_ARCS is nonzero, this function instruments the edges in
754 the flow graph that are needed to reconstruct the dynamic behavior of the
757 When FLAG_BRANCH_PROBABILITIES is nonzero, this function reads auxiliary
758 information from a data file containing edge count information from previous
759 executions of the function being compiled. In this case, the flow graph is
760 annotated with actual execution counts, which are later propagated into the
761 rtl for optimization purposes.
763 Main entry point of this file. */
770 unsigned num_edges
, ignored_edges
;
771 unsigned num_instrumented
;
772 struct edge_list
*el
;
773 histogram_values values
= NULL
;
775 total_num_times_called
++;
777 flow_call_edges_add (NULL
);
778 add_noreturn_fake_exit_edges ();
780 /* We can't handle cyclic regions constructed using abnormal edges.
781 To avoid these we replace every source of abnormal edge by a fake
782 edge from entry node and every destination by fake edge to exit.
783 This keeps graph acyclic and our calculation exact for all normal
784 edges except for exit and entrance ones.
786 We also add fake exit edges for each call and asm statement in the
787 basic, since it may not return. */
791 int need_exit_edge
= 0, need_entry_edge
= 0;
792 int have_exit_edge
= 0, have_entry_edge
= 0;
796 /* Functions returning multiple times are not handled by extra edges.
797 Instead we simply allow negative counts on edges from exit to the
798 block past call and corresponding probabilities. We can't go
799 with the extra edges because that would result in flowgraph that
800 needs to have fake edges outside the spanning tree. */
802 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
804 block_stmt_iterator bsi
;
807 /* It may happen that there are compiler generated statements
808 without a locus at all. Go through the basic block from the
809 last to the first statement looking for a locus. */
810 for (bsi
= bsi_last (bb
); !bsi_end_p (bsi
); bsi_prev (&bsi
))
812 last
= bsi_stmt (bsi
);
813 if (EXPR_LOCUS (last
))
817 /* Edge with goto locus might get wrong coverage info unless
818 it is the only edge out of BB.
819 Don't do that when the locuses match, so
820 if (blah) goto something;
821 is not computed twice. */
822 if (last
&& EXPR_LOCUS (last
)
824 && !single_succ_p (bb
)
825 #ifdef USE_MAPPED_LOCATION
826 && (LOCATION_FILE (e
->goto_locus
)
827 != LOCATION_FILE (EXPR_LOCATION (last
))
828 || (LOCATION_LINE (e
->goto_locus
)
829 != LOCATION_LINE (EXPR_LOCATION (last
)))))
831 && (e
->goto_locus
->file
!= EXPR_LOCUS (last
)->file
832 || (e
->goto_locus
->line
!= EXPR_LOCUS (last
)->line
)))
835 basic_block
new = split_edge (e
);
836 single_succ_edge (new)->goto_locus
= e
->goto_locus
;
838 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
839 && e
->dest
!= EXIT_BLOCK_PTR
)
841 if (e
->dest
== EXIT_BLOCK_PTR
)
844 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
846 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
847 && e
->src
!= ENTRY_BLOCK_PTR
)
849 if (e
->src
== ENTRY_BLOCK_PTR
)
853 if (need_exit_edge
&& !have_exit_edge
)
856 fprintf (dump_file
, "Adding fake exit edge to bb %i\n",
858 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
860 if (need_entry_edge
&& !have_entry_edge
)
863 fprintf (dump_file
, "Adding fake entry edge to bb %i\n",
865 make_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FAKE
);
869 el
= create_edge_list ();
870 num_edges
= NUM_EDGES (el
);
871 alloc_aux_for_edges (sizeof (struct edge_info
));
873 /* The basic blocks are expected to be numbered sequentially. */
877 for (i
= 0 ; i
< num_edges
; i
++)
879 edge e
= INDEX_EDGE (el
, i
);
882 /* Mark edges we've replaced by fake edges above as ignored. */
883 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
884 && e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
)
886 EDGE_INFO (e
)->ignore
= 1;
891 /* Create spanning tree from basic block graph, mark each edge that is
892 on the spanning tree. We insert as many abnormal and critical edges
893 as possible to minimize number of edge splits necessary. */
895 find_spanning_tree (el
);
897 /* Fake edges that are not on the tree will not be instrumented, so
898 mark them ignored. */
899 for (num_instrumented
= i
= 0; i
< num_edges
; i
++)
901 edge e
= INDEX_EDGE (el
, i
);
902 struct edge_info
*inf
= EDGE_INFO (e
);
904 if (inf
->ignore
|| inf
->on_tree
)
906 else if (e
->flags
& EDGE_FAKE
)
915 total_num_blocks
+= n_basic_blocks
;
917 fprintf (dump_file
, "%d basic blocks\n", n_basic_blocks
);
919 total_num_edges
+= num_edges
;
921 fprintf (dump_file
, "%d edges\n", num_edges
);
923 total_num_edges_ignored
+= ignored_edges
;
925 fprintf (dump_file
, "%d ignored edges\n", ignored_edges
);
927 /* Write the data from which gcov can reconstruct the basic block
930 /* Basic block flags */
931 if (coverage_begin_output ())
933 gcov_position_t offset
;
935 offset
= gcov_write_tag (GCOV_TAG_BLOCKS
);
936 for (i
= 0; i
!= (unsigned) (n_basic_blocks
); i
++)
937 gcov_write_unsigned (0);
938 gcov_write_length (offset
);
941 /* Keep all basic block indexes nonnegative in the gcov output.
942 Index 0 is used for entry block, last index is for exit block.
944 ENTRY_BLOCK_PTR
->index
= 1;
945 EXIT_BLOCK_PTR
->index
= last_basic_block
;
948 if (coverage_begin_output ())
950 gcov_position_t offset
;
952 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
957 offset
= gcov_write_tag (GCOV_TAG_ARCS
);
958 gcov_write_unsigned (BB_TO_GCOV_INDEX (bb
));
960 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
962 struct edge_info
*i
= EDGE_INFO (e
);
965 unsigned flag_bits
= 0;
968 flag_bits
|= GCOV_ARC_ON_TREE
;
969 if (e
->flags
& EDGE_FAKE
)
970 flag_bits
|= GCOV_ARC_FAKE
;
971 if (e
->flags
& EDGE_FALLTHRU
)
972 flag_bits
|= GCOV_ARC_FALLTHROUGH
;
973 /* On trees we don't have fallthru flags, but we can
974 recompute them from CFG shape. */
976 && e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)
977 && e
->src
->next_bb
== e
->dest
)
978 flag_bits
|= GCOV_ARC_FALLTHROUGH
;
980 gcov_write_unsigned (BB_TO_GCOV_INDEX (e
->dest
));
981 gcov_write_unsigned (flag_bits
);
985 gcov_write_length (offset
);
990 if (coverage_begin_output ())
992 /* Initialize the output. */
993 output_location (NULL
, 0, NULL
, NULL
);
997 gcov_position_t offset
;
1001 rtx insn
= BB_HEAD (bb
);
1002 int ignore_next_note
= 0;
1006 /* We are looking for line number notes. Search backward
1007 before basic block to find correct ones. */
1008 insn
= prev_nonnote_insn (insn
);
1010 insn
= get_insns ();
1012 insn
= NEXT_INSN (insn
);
1014 while (insn
!= BB_END (bb
))
1018 /* Must ignore the line number notes that
1019 immediately follow the end of an inline function
1020 to avoid counting it twice. There is a note
1021 before the call, and one after the call. */
1022 if (NOTE_LINE_NUMBER (insn
)
1023 == NOTE_INSN_REPEATED_LINE_NUMBER
)
1024 ignore_next_note
= 1;
1025 else if (NOTE_LINE_NUMBER (insn
) <= 0)
1027 else if (ignore_next_note
)
1028 ignore_next_note
= 0;
1031 expanded_location s
;
1032 NOTE_EXPANDED_LOCATION (s
, insn
);
1033 output_location (s
.file
, s
.line
, &offset
, bb
);
1036 insn
= NEXT_INSN (insn
);
1041 /* A file of NULL indicates the end of run. */
1042 gcov_write_unsigned (0);
1043 gcov_write_string (NULL
);
1044 gcov_write_length (offset
);
1050 gcov_position_t offset
;
1054 block_stmt_iterator bsi
;
1058 if (bb
== ENTRY_BLOCK_PTR
->next_bb
)
1060 expanded_location curr_location
=
1061 expand_location (DECL_SOURCE_LOCATION
1062 (current_function_decl
));
1063 output_location (curr_location
.file
, curr_location
.line
,
1067 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1069 tree stmt
= bsi_stmt (bsi
);
1070 if (EXPR_HAS_LOCATION (stmt
))
1071 output_location (EXPR_FILENAME (stmt
),
1076 /* Notice GOTO expressions we eliminated while constructing the
1078 if (single_succ_p (bb
) && single_succ_edge (bb
)->goto_locus
)
1080 /* ??? source_locus type is marked deprecated in input.h. */
1081 source_locus curr_location
= single_succ_edge (bb
)->goto_locus
;
1082 /* ??? The FILE/LINE API is inconsistent for these cases. */
1083 #ifdef USE_MAPPED_LOCATION
1084 output_location (LOCATION_FILE (curr_location
),
1085 LOCATION_LINE (curr_location
),
1088 output_location (curr_location
->file
, curr_location
->line
,
1095 /* A file of NULL indicates the end of run. */
1096 gcov_write_unsigned (0);
1097 gcov_write_string (NULL
);
1098 gcov_write_length (offset
);
1104 ENTRY_BLOCK_PTR
->index
= ENTRY_BLOCK
;
1105 EXIT_BLOCK_PTR
->index
= EXIT_BLOCK
;
1106 #undef BB_TO_GCOV_INDEX
1108 if (flag_profile_values
)
1109 find_values_to_profile (&values
);
1111 if (flag_branch_probabilities
)
1113 compute_branch_probabilities ();
1114 if (flag_profile_values
)
1115 compute_value_histograms (values
);
1118 remove_fake_edges ();
1120 /* For each edge not on the spanning tree, add counting code. */
1121 if (profile_arc_flag
1122 && coverage_counter_alloc (GCOV_COUNTER_ARCS
, num_instrumented
))
1124 unsigned n_instrumented
;
1126 profile_hooks
->init_edge_profiler ();
1128 n_instrumented
= instrument_edges (el
);
1130 gcc_assert (n_instrumented
== num_instrumented
);
1132 if (flag_profile_values
)
1133 instrument_values (values
);
1135 /* Commit changes done by instrumentation. */
1137 bsi_commit_edge_inserts ();
1140 commit_edge_insertions_watch_calls ();
1141 allocate_reg_info (max_reg_num (), FALSE
, FALSE
);
1145 free_aux_for_edges ();
1149 /* Re-merge split basic blocks and the mess introduced by
1150 insert_insn_on_edge. */
1151 cleanup_cfg (profile_arc_flag
? CLEANUP_EXPENSIVE
: 0);
1153 dump_flow_info (dump_file
, dump_flags
);
1156 free_edge_list (el
);
1157 if (flag_branch_probabilities
)
1158 profile_status
= PROFILE_READ
;
1159 coverage_end_function ();
1162 /* Union find algorithm implementation for the basic blocks using
1166 find_group (basic_block bb
)
1168 basic_block group
= bb
, bb1
;
1170 while ((basic_block
) group
->aux
!= group
)
1171 group
= (basic_block
) group
->aux
;
1173 /* Compress path. */
1174 while ((basic_block
) bb
->aux
!= group
)
1176 bb1
= (basic_block
) bb
->aux
;
1177 bb
->aux
= (void *) group
;
1184 union_groups (basic_block bb1
, basic_block bb2
)
1186 basic_block bb1g
= find_group (bb1
);
1187 basic_block bb2g
= find_group (bb2
);
1189 /* ??? I don't have a place for the rank field. OK. Lets go w/o it,
1190 this code is unlikely going to be performance problem anyway. */
1191 gcc_assert (bb1g
!= bb2g
);
1196 /* This function searches all of the edges in the program flow graph, and puts
1197 as many bad edges as possible onto the spanning tree. Bad edges include
1198 abnormals edges, which can't be instrumented at the moment. Since it is
1199 possible for fake edges to form a cycle, we will have to develop some
1200 better way in the future. Also put critical edges to the tree, since they
1201 are more expensive to instrument. */
1204 find_spanning_tree (struct edge_list
*el
)
1207 int num_edges
= NUM_EDGES (el
);
1210 /* We use aux field for standard union-find algorithm. */
1211 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1214 /* Add fake edge exit to entry we can't instrument. */
1215 union_groups (EXIT_BLOCK_PTR
, ENTRY_BLOCK_PTR
);
1217 /* First add all abnormal edges to the tree unless they form a cycle. Also
1218 add all edges to EXIT_BLOCK_PTR to avoid inserting profiling code behind
1219 setting return value from function. */
1220 for (i
= 0; i
< num_edges
; i
++)
1222 edge e
= INDEX_EDGE (el
, i
);
1223 if (((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
| EDGE_FAKE
))
1224 || e
->dest
== EXIT_BLOCK_PTR
)
1225 && !EDGE_INFO (e
)->ignore
1226 && (find_group (e
->src
) != find_group (e
->dest
)))
1229 fprintf (dump_file
, "Abnormal edge %d to %d put to tree\n",
1230 e
->src
->index
, e
->dest
->index
);
1231 EDGE_INFO (e
)->on_tree
= 1;
1232 union_groups (e
->src
, e
->dest
);
1236 /* Now insert all critical edges to the tree unless they form a cycle. */
1237 for (i
= 0; i
< num_edges
; i
++)
1239 edge e
= INDEX_EDGE (el
, i
);
1240 if (EDGE_CRITICAL_P (e
) && !EDGE_INFO (e
)->ignore
1241 && find_group (e
->src
) != find_group (e
->dest
))
1244 fprintf (dump_file
, "Critical edge %d to %d put to tree\n",
1245 e
->src
->index
, e
->dest
->index
);
1246 EDGE_INFO (e
)->on_tree
= 1;
1247 union_groups (e
->src
, e
->dest
);
1251 /* And now the rest. */
1252 for (i
= 0; i
< num_edges
; i
++)
1254 edge e
= INDEX_EDGE (el
, i
);
1255 if (!EDGE_INFO (e
)->ignore
1256 && find_group (e
->src
) != find_group (e
->dest
))
1259 fprintf (dump_file
, "Normal edge %d to %d put to tree\n",
1260 e
->src
->index
, e
->dest
->index
);
1261 EDGE_INFO (e
)->on_tree
= 1;
1262 union_groups (e
->src
, e
->dest
);
1266 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1270 /* Perform file-level initialization for branch-prob processing. */
1273 init_branch_prob (void)
1277 total_num_blocks
= 0;
1278 total_num_edges
= 0;
1279 total_num_edges_ignored
= 0;
1280 total_num_edges_instrumented
= 0;
1281 total_num_blocks_created
= 0;
1282 total_num_passes
= 0;
1283 total_num_times_called
= 0;
1284 total_num_branches
= 0;
1285 total_num_never_executed
= 0;
1286 for (i
= 0; i
< 20; i
++)
1287 total_hist_br_prob
[i
] = 0;
1290 /* Performs file-level cleanup after branch-prob processing
1294 end_branch_prob (void)
1298 fprintf (dump_file
, "\n");
1299 fprintf (dump_file
, "Total number of blocks: %d\n",
1301 fprintf (dump_file
, "Total number of edges: %d\n", total_num_edges
);
1302 fprintf (dump_file
, "Total number of ignored edges: %d\n",
1303 total_num_edges_ignored
);
1304 fprintf (dump_file
, "Total number of instrumented edges: %d\n",
1305 total_num_edges_instrumented
);
1306 fprintf (dump_file
, "Total number of blocks created: %d\n",
1307 total_num_blocks_created
);
1308 fprintf (dump_file
, "Total number of graph solution passes: %d\n",
1310 if (total_num_times_called
!= 0)
1311 fprintf (dump_file
, "Average number of graph solution passes: %d\n",
1312 (total_num_passes
+ (total_num_times_called
>> 1))
1313 / total_num_times_called
);
1314 fprintf (dump_file
, "Total number of branches: %d\n",
1315 total_num_branches
);
1316 fprintf (dump_file
, "Total number of branches never executed: %d\n",
1317 total_num_never_executed
);
1318 if (total_num_branches
)
1322 for (i
= 0; i
< 10; i
++)
1323 fprintf (dump_file
, "%d%% branches in range %d-%d%%\n",
1324 (total_hist_br_prob
[i
] + total_hist_br_prob
[19-i
]) * 100
1325 / total_num_branches
, 5*i
, 5*i
+5);
1330 /* Set up hooks to enable tree-based profiling. */
1333 tree_register_profile_hooks (void)
1335 gcc_assert (ir_type ());
1336 profile_hooks
= &tree_profile_hooks
;
1340 /* Do branch profiling and static profile estimation passes. */
1342 rest_of_handle_branch_prob (void)
1346 /* Discover and record the loop depth at the head of each basic
1347 block. The loop infrastructure does the real job for us. */
1348 flow_loops_find (&loops
);
1351 flow_loops_dump (&loops
, dump_file
, NULL
, 0);
1353 /* Estimate using heuristics if no profiling info is available. */
1354 if (flag_guess_branch_prob
1355 && profile_status
== PROFILE_ABSENT
)
1356 estimate_probability (&loops
);
1358 flow_loops_free (&loops
);
1359 free_dominance_info (CDI_DOMINATORS
);
1363 struct tree_opt_pass pass_branch_prob
=
1367 rest_of_handle_branch_prob
, /* execute */
1370 0, /* static_pass_number */
1371 TV_BRANCH_PROB
, /* tv_id */
1372 0, /* properties_required */
1373 0, /* properties_provided */
1374 0, /* properties_destroyed */
1375 0, /* todo_flags_start */
1376 TODO_dump_func
, /* todo_flags_finish */