1 /* Calculate branch probabilities, and basic block execution counts.
2 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998, 1999,
3 2000, 2001 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, 59 Temple Place - Suite 330, Boston, MA
25 /* ??? Register allocation should use basic block execution counts to
26 give preference to the most commonly executed blocks. */
28 /* ??? The .da files are not safe. Changing the program after creating .da
29 files or using different options when compiling with -fbranch-probabilities
30 can result the arc data not matching the program. Maybe add instrumented
31 arc count to .bbg file? Maybe check whether PFG matches the .bbg file? */
33 /* ??? Should calculate branch probabilities before instrumenting code, since
34 then we can use arc counts to help decide which arcs to instrument. */
41 #include "insn-config.h"
48 #include "hard-reg-set.h"
49 #include "basic-block.h"
52 #include "langhooks.h"
54 /* Additional information about the edges we need. */
57 unsigned int count_valid
: 1;
58 unsigned int on_tree
: 1;
59 unsigned int ignore
: 1;
63 unsigned int count_valid
: 1;
68 #define EDGE_INFO(e) ((struct edge_info *) (e)->aux)
69 #define BB_INFO(b) ((struct bb_info *) (b)->aux)
71 /* Keep all basic block indexes nonnegative in the gcov output. Index 0
72 is used for entry block, last block exit block. */
73 #define GCOV_INDEX_TO_BB(i) ((i) == 0 ? ENTRY_BLOCK_PTR \
74 : (((i) == n_basic_blocks + 1) \
75 ? EXIT_BLOCK_PTR : BASIC_BLOCK ((i)-1)))
76 #define BB_TO_GCOV_INDEX(bb) ((bb) == ENTRY_BLOCK_PTR ? 0 \
77 : ((bb) == EXIT_BLOCK_PTR \
78 ? n_basic_blocks + 1 : (bb)->index + 1))
80 /* Name and file pointer of the output file for the basic block graph. */
82 static FILE *bbg_file
;
84 /* Name and file pointer of the input file for the arc count data. */
88 /* Pointer of the output file for the basic block/line number map. */
91 /* Last source file name written to bb_file. */
93 static char *last_bb_file_name
;
95 /* Used by final, for allocating the proper amount of storage for the
96 instrumented arc execution counts. */
98 int count_instrumented_edges
;
100 /* Collect statistics on the performance of this pass for the entire source
103 static int total_num_blocks
;
104 static int total_num_edges
;
105 static int total_num_edges_ignored
;
106 static int total_num_edges_instrumented
;
107 static int total_num_blocks_created
;
108 static int total_num_passes
;
109 static int total_num_times_called
;
110 static int total_hist_br_prob
[20];
111 static int total_num_never_executed
;
112 static int total_num_branches
;
114 /* Forward declarations. */
115 static void find_spanning_tree
PARAMS ((struct edge_list
*));
116 static void init_edge_profiler
PARAMS ((void));
117 static rtx gen_edge_profiler
PARAMS ((int));
118 static void instrument_edges
PARAMS ((struct edge_list
*));
119 static void output_gcov_string
PARAMS ((const char *, long));
120 static void compute_branch_probabilities
PARAMS ((void));
121 static basic_block find_group
PARAMS ((basic_block
));
122 static void union_groups
PARAMS ((basic_block
, basic_block
));
124 /* If non-zero, we need to output a constructor to set up the
125 per-object-file data. */
126 static int need_func_profiler
= 0;
128 /* Add edge instrumentation code to the entire insn chain.
130 F is the first insn of the chain.
131 NUM_BLOCKS is the number of basic blocks found in F. */
134 instrument_edges (el
)
135 struct edge_list
*el
;
138 int num_instr_edges
= 0;
139 int num_edges
= NUM_EDGES (el
);
140 remove_fake_edges ();
142 for (i
= 0; i
< n_basic_blocks
+ 2; i
++)
144 basic_block bb
= GCOV_INDEX_TO_BB (i
);
148 struct edge_info
*inf
= EDGE_INFO (e
);
149 if (!inf
->ignore
&& !inf
->on_tree
)
151 if (e
->flags
& EDGE_ABNORMAL
)
154 fprintf (rtl_dump_file
, "Edge %d to %d instrumented%s\n",
155 e
->src
->index
, e
->dest
->index
,
156 EDGE_CRITICAL_P (e
) ? " (and split)" : "");
157 need_func_profiler
= 1;
158 insert_insn_on_edge (
159 gen_edge_profiler (total_num_edges_instrumented
160 + num_instr_edges
++), e
);
166 total_num_edges_instrumented
+= num_instr_edges
;
167 count_instrumented_edges
= total_num_edges_instrumented
;
169 total_num_blocks_created
+= num_edges
;
171 fprintf (rtl_dump_file
, "%d edges instrumented\n", num_instr_edges
);
173 commit_edge_insertions_watch_calls ();
176 /* Output STRING to bb_file, surrounded by DELIMITER. */
179 output_gcov_string (string
, delimiter
)
185 /* Write a delimiter to indicate that a file name follows. */
186 __write_long (delimiter
, bb_file
, 4);
188 /* Write the string. */
189 temp
= strlen (string
) + 1;
190 fwrite (string
, temp
, 1, bb_file
);
192 /* Append a few zeros, to align the output to a 4 byte boundary. */
198 c
[0] = c
[1] = c
[2] = c
[3] = 0;
199 fwrite (c
, sizeof (char), 4 - temp
, bb_file
);
202 /* Store another delimiter in the .bb file, just to make it easy to find
203 the end of the file name. */
204 __write_long (delimiter
, bb_file
, 4);
208 /* Compute the branch probabilities for the various branches.
209 Annotate them accordingly. */
212 compute_branch_probabilities ()
218 int hist_br_prob
[20];
219 int num_never_executed
;
222 /* Attach extra info block to each bb. */
224 alloc_aux_for_blocks (sizeof (struct bb_info
));
225 for (i
= 0; i
< n_basic_blocks
+ 2; i
++)
227 basic_block bb
= GCOV_INDEX_TO_BB (i
);
230 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
231 if (!EDGE_INFO (e
)->ignore
)
232 BB_INFO (bb
)->succ_count
++;
233 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
234 if (!EDGE_INFO (e
)->ignore
)
235 BB_INFO (bb
)->pred_count
++;
238 /* Avoid predicting entry on exit nodes. */
239 BB_INFO (EXIT_BLOCK_PTR
)->succ_count
= 2;
240 BB_INFO (ENTRY_BLOCK_PTR
)->pred_count
= 2;
242 /* For each edge not on the spanning tree, set its execution count from
245 /* The first count in the .da file is the number of times that the function
246 was entered. This is the exec_count for block zero. */
248 for (i
= 0; i
< n_basic_blocks
+ 2; i
++)
250 basic_block bb
= GCOV_INDEX_TO_BB (i
);
252 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
253 if (!EDGE_INFO (e
)->ignore
&& !EDGE_INFO (e
)->on_tree
)
259 __read_gcov_type (&value
, da_file
, 8);
264 EDGE_INFO (e
)->count_valid
= 1;
265 BB_INFO (bb
)->succ_count
--;
266 BB_INFO (e
->dest
)->pred_count
--;
269 fprintf (rtl_dump_file
, "\nRead edge from %i to %i, count:",
270 bb
->index
, e
->dest
->index
);
271 fprintf (rtl_dump_file
, HOST_WIDEST_INT_PRINT_DEC
,
272 (HOST_WIDEST_INT
) e
->count
);
278 fprintf (rtl_dump_file
, "\n%d edge counts read\n", num_edges
);
280 /* For every block in the file,
281 - if every exit/entrance edge has a known count, then set the block count
282 - if the block count is known, and every exit/entrance edge but one has
283 a known execution count, then set the count of the remaining edge
285 As edge counts are set, decrement the succ/pred count, but don't delete
286 the edge, that way we can easily tell when all edges are known, or only
287 one edge is unknown. */
289 /* The order that the basic blocks are iterated through is important.
290 Since the code that finds spanning trees starts with block 0, low numbered
291 edges are put on the spanning tree in preference to high numbered edges.
292 Hence, most instrumented edges are at the end. Graph solving works much
293 faster if we propagate numbers from the end to the start.
295 This takes an average of slightly more than 3 passes. */
303 for (i
= n_basic_blocks
+ 1; i
>= 0; i
--)
305 basic_block bb
= GCOV_INDEX_TO_BB (i
);
306 struct bb_info
*bi
= BB_INFO (bb
);
307 if (! bi
->count_valid
)
309 if (bi
->succ_count
== 0)
314 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
320 else if (bi
->pred_count
== 0)
325 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
334 if (bi
->succ_count
== 1)
339 /* One of the counts will be invalid, but it is zero,
340 so adding it in also doesn't hurt. */
341 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
344 /* Seedgeh for the invalid edge, and set its count. */
345 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
346 if (! EDGE_INFO (e
)->count_valid
&& ! EDGE_INFO (e
)->ignore
)
349 /* Calculate count for remaining edge by conservation. */
350 total
= bb
->count
- total
;
354 EDGE_INFO (e
)->count_valid
= 1;
358 BB_INFO (e
->dest
)->pred_count
--;
361 if (bi
->pred_count
== 1)
366 /* One of the counts will be invalid, but it is zero,
367 so adding it in also doesn't hurt. */
368 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
371 /* Seedgeh for the invalid edge, and set its count. */
372 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
373 if (! EDGE_INFO (e
)->count_valid
&& ! EDGE_INFO (e
)->ignore
)
376 /* Calculate count for remaining edge by conservation. */
377 total
= bb
->count
- total
+ e
->count
;
381 EDGE_INFO (e
)->count_valid
= 1;
385 BB_INFO (e
->src
)->succ_count
--;
392 dump_flow_info (rtl_dump_file
);
394 total_num_passes
+= passes
;
396 fprintf (rtl_dump_file
, "Graph solving took %d passes.\n\n", passes
);
398 /* If the graph has been correctly solved, every block will have a
399 succ and pred count of zero. */
400 for (i
= 0; i
< n_basic_blocks
; i
++)
402 basic_block bb
= BASIC_BLOCK (i
);
403 if (BB_INFO (bb
)->succ_count
|| BB_INFO (bb
)->pred_count
)
407 /* For every edge, calculate its branch probability and add a reg_note
408 to the branch insn to indicate this. */
410 for (i
= 0; i
< 20; i
++)
412 num_never_executed
= 0;
415 for (i
= 0; i
<= n_basic_blocks
+ 1; i
++)
417 basic_block bb
= GCOV_INDEX_TO_BB (i
);
425 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
427 e
->probability
= (e
->count
* REG_BR_PROB_BASE
+ total
/ 2) / total
;
428 if (e
->probability
< 0 || e
->probability
> REG_BR_PROB_BASE
)
430 error ("corrupted profile info: prob for %d-%d thought to be %d",
431 e
->src
->index
, e
->dest
->index
, e
->probability
);
432 e
->probability
= REG_BR_PROB_BASE
/ 2;
436 && any_condjump_p (bb
->end
)
437 && bb
->succ
->succ_next
)
443 /* Find the branch edge. It is possible that we do have fake
445 for (e
= bb
->succ
; e
->flags
& (EDGE_FAKE
| EDGE_FALLTHRU
);
447 continue; /* Loop body has been intentionally left blank. */
449 prob
= e
->probability
;
450 index
= prob
* 20 / REG_BR_PROB_BASE
;
454 hist_br_prob
[index
]++;
456 note
= find_reg_note (bb
->end
, REG_BR_PROB
, 0);
457 /* There may be already note put by some other pass, such
458 as builtin_expect expander. */
460 XEXP (note
, 0) = GEN_INT (prob
);
463 = gen_rtx_EXPR_LIST (REG_BR_PROB
, GEN_INT (prob
),
464 REG_NOTES (bb
->end
));
468 /* Otherwise distribute the probabilities evenly so we get sane sum.
469 Use simple heuristics that if there are normal edges, give all abnormals
470 frequency of 0, otherwise distribute the frequency over abnormals
471 (this is the case of noreturn calls). */
474 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
475 if (!(e
->flags
& (EDGE_COMPLEX
| EDGE_FAKE
)))
479 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
480 if (!(e
->flags
& (EDGE_COMPLEX
| EDGE_FAKE
)))
481 e
->probability
= REG_BR_PROB_BASE
/ total
;
487 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
489 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
490 e
->probability
= REG_BR_PROB_BASE
/ total
;
493 && any_condjump_p (bb
->end
)
494 && bb
->succ
->succ_next
)
495 num_branches
++, num_never_executed
;
501 fprintf (rtl_dump_file
, "%d branches\n", num_branches
);
502 fprintf (rtl_dump_file
, "%d branches never executed\n",
505 for (i
= 0; i
< 10; i
++)
506 fprintf (rtl_dump_file
, "%d%% branches in range %d-%d%%\n",
507 (hist_br_prob
[i
] + hist_br_prob
[19-i
]) * 100 / num_branches
,
510 total_num_branches
+= num_branches
;
511 total_num_never_executed
+= num_never_executed
;
512 for (i
= 0; i
< 20; i
++)
513 total_hist_br_prob
[i
] += hist_br_prob
[i
];
515 fputc ('\n', rtl_dump_file
);
516 fputc ('\n', rtl_dump_file
);
519 free_aux_for_blocks ();
522 /* Instrument and/or analyze program behavior based on program flow graph.
523 In either case, this function builds a flow graph for the function being
524 compiled. The flow graph is stored in BB_GRAPH.
526 When FLAG_PROFILE_ARCS is nonzero, this function instruments the edges in
527 the flow graph that are needed to reconstruct the dynamic behavior of the
530 When FLAG_BRANCH_PROBABILITIES is nonzero, this function reads auxiliary
531 information from a data file containing edge count information from previous
532 executions of the function being compiled. In this case, the flow graph is
533 annotated with actual execution counts, which are later propagated into the
534 rtl for optimization purposes.
536 Main entry point of this file. */
542 int num_edges
, ignored_edges
;
543 struct edge_list
*el
;
545 /* Start of a function. */
546 if (flag_test_coverage
)
547 output_gcov_string (current_function_name
, (long) -2);
549 total_num_times_called
++;
551 flow_call_edges_add (NULL
);
552 add_noreturn_fake_exit_edges ();
554 /* We can't handle cyclic regions constructed using abnormal edges.
555 To avoid these we replace every source of abnormal edge by a fake
556 edge from entry node and every destination by fake edge to exit.
557 This keeps graph acyclic and our calculation exact for all normal
558 edges except for exit and entrance ones.
560 We also add fake exit edges for each call and asm statement in the
561 basic, since it may not return. */
563 for (i
= 0; i
< n_basic_blocks
; i
++)
565 int need_exit_edge
= 0, need_entry_edge
= 0;
566 int have_exit_edge
= 0, have_entry_edge
= 0;
567 basic_block bb
= BASIC_BLOCK (i
);
571 /* Add fake edges from entry block to the call insns that may return
572 twice. The CFG is not quite correct then, as call insn plays more
573 role of CODE_LABEL, but for our purposes, everything should be OK,
574 as we never insert code to the beggining of basic block. */
575 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
576 insn
= NEXT_INSN (insn
))
578 if (GET_CODE (insn
) == CALL_INSN
579 && find_reg_note (insn
, REG_SETJMP
, NULL
))
581 if (GET_CODE (bb
->head
) == CODE_LABEL
582 || insn
!= NEXT_INSN (bb
->head
))
584 e
= split_block (bb
, PREV_INSN (insn
));
585 make_edge (ENTRY_BLOCK_PTR
, e
->dest
, EDGE_FAKE
);
590 /* We should not get abort here, as call to setjmp should not
591 be the very first instruction of function. */
594 make_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FAKE
);
599 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
601 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
602 && e
->dest
!= EXIT_BLOCK_PTR
)
604 if (e
->dest
== EXIT_BLOCK_PTR
)
607 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
609 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
610 && e
->src
!= ENTRY_BLOCK_PTR
)
612 if (e
->src
== ENTRY_BLOCK_PTR
)
616 if (need_exit_edge
&& !have_exit_edge
)
619 fprintf (rtl_dump_file
, "Adding fake exit edge to bb %i\n",
621 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
623 if (need_entry_edge
&& !have_entry_edge
)
626 fprintf (rtl_dump_file
, "Adding fake entry edge to bb %i\n",
628 make_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FAKE
);
632 el
= create_edge_list ();
633 num_edges
= NUM_EDGES (el
);
634 alloc_aux_for_edges (sizeof (struct edge_info
));
637 for (i
= 0 ; i
< num_edges
; i
++)
639 edge e
= INDEX_EDGE (el
, i
);
642 /* Mark edges we've replaced by fake edges above as ignored. */
643 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
))
644 && e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
)
646 EDGE_INFO (e
)->ignore
= 1;
651 #ifdef ENABLE_CHECKING
655 /* Output line number information about each basic block for
657 if (flag_test_coverage
)
660 for (i
= 0 ; i
< n_basic_blocks
; i
++)
662 basic_block bb
= BASIC_BLOCK (i
);
664 static int ignore_next_note
= 0;
666 /* We are looking for line number notes. Search backward before
667 basic block to find correct ones. */
668 insn
= prev_nonnote_insn (insn
);
672 insn
= NEXT_INSN (insn
);
674 /* Output a zero to the .bb file to indicate that a new
675 block list is starting. */
676 __write_long (0, bb_file
, 4);
678 while (insn
!= bb
->end
)
680 if (GET_CODE (insn
) == NOTE
)
682 /* Must ignore the line number notes that immediately
683 follow the end of an inline function to avoid counting
684 it twice. There is a note before the call, and one
686 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_REPEATED_LINE_NUMBER
)
687 ignore_next_note
= 1;
688 else if (NOTE_LINE_NUMBER (insn
) > 0)
690 if (ignore_next_note
)
691 ignore_next_note
= 0;
694 /* If this is a new source file, then output the
695 file's name to the .bb file. */
696 if (! last_bb_file_name
697 || strcmp (NOTE_SOURCE_FILE (insn
),
700 if (last_bb_file_name
)
701 free (last_bb_file_name
);
703 = xstrdup (NOTE_SOURCE_FILE (insn
));
704 output_gcov_string (NOTE_SOURCE_FILE (insn
),
707 /* Output the line number to the .bb file. Must be
708 done after the output_bb_profile_data() call, and
709 after the file name is written, to ensure that it
710 is correctly handled by gcov. */
711 __write_long (NOTE_LINE_NUMBER (insn
), bb_file
, 4);
715 insn
= NEXT_INSN (insn
);
718 __write_long (0, bb_file
, 4);
721 /* Create spanning tree from basic block graph, mark each edge that is
722 on the spanning tree. We insert as many abnormal and critical edges
723 as possible to minimize number of edge splits necessary. */
725 find_spanning_tree (el
);
727 /* Fake edges that are not on the tree will not be instrumented, so
728 mark them ignored. */
729 for (i
= 0; i
< num_edges
; i
++)
731 edge e
= INDEX_EDGE (el
, i
);
732 struct edge_info
*inf
= EDGE_INFO (e
);
733 if ((e
->flags
& EDGE_FAKE
) && !inf
->ignore
&& !inf
->on_tree
)
740 total_num_blocks
+= n_basic_blocks
+ 2;
742 fprintf (rtl_dump_file
, "%d basic blocks\n", n_basic_blocks
);
744 total_num_edges
+= num_edges
;
746 fprintf (rtl_dump_file
, "%d edges\n", num_edges
);
748 total_num_edges_ignored
+= ignored_edges
;
750 fprintf (rtl_dump_file
, "%d ignored edges\n", ignored_edges
);
752 /* Create a .bbg file from which gcov can reconstruct the basic block
753 graph. First output the number of basic blocks, and then for every
754 edge output the source and target basic block numbers.
755 NOTE: The format of this file must be compatible with gcov. */
757 if (flag_test_coverage
)
761 /* The plus 2 stands for entry and exit block. */
762 __write_long (n_basic_blocks
+ 2, bbg_file
, 4);
763 __write_long (num_edges
- ignored_edges
+ 1, bbg_file
, 4);
765 for (i
= 0; i
< n_basic_blocks
+ 1; i
++)
767 basic_block bb
= GCOV_INDEX_TO_BB (i
);
771 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
772 if (!EDGE_INFO (e
)->ignore
)
774 __write_long (count
, bbg_file
, 4);
776 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
778 struct edge_info
*i
= EDGE_INFO (e
);
784 if (e
->flags
& EDGE_FAKE
)
786 if (e
->flags
& EDGE_FALLTHRU
)
789 __write_long (BB_TO_GCOV_INDEX (e
->dest
), bbg_file
, 4);
790 __write_long (flag_bits
, bbg_file
, 4);
794 /* Emit fake loopback edge for EXIT block to maintain compatibility with
796 __write_long (1, bbg_file
, 4);
797 __write_long (0, bbg_file
, 4);
798 __write_long (0x1, bbg_file
, 4);
800 /* Emit a -1 to separate the list of all edges from the list of
801 loop back edges that follows. */
802 __write_long (-1, bbg_file
, 4);
805 if (flag_branch_probabilities
)
806 compute_branch_probabilities ();
808 /* For each edge not on the spanning tree, add counting code as rtl. */
810 if (profile_arc_flag
)
812 instrument_edges (el
);
813 allocate_reg_info (max_reg_num (), FALSE
, FALSE
);
816 remove_fake_edges ();
817 /* Re-merge split basic blocks and the mess introduced by
818 insert_insn_on_edge. */
819 cleanup_cfg (profile_arc_flag
? CLEANUP_EXPENSIVE
: 0);
821 dump_flow_info (rtl_dump_file
);
823 free_aux_for_edges ();
827 /* Union find algorithm implementation for the basic blocks using
834 basic_block group
= bb
, bb1
;
836 while ((basic_block
) group
->aux
!= group
)
837 group
= (basic_block
) group
->aux
;
840 while ((basic_block
) bb
->aux
!= group
)
842 bb1
= (basic_block
) bb
->aux
;
843 bb
->aux
= (void *) group
;
850 union_groups (bb1
, bb2
)
851 basic_block bb1
, bb2
;
853 basic_block bb1g
= find_group (bb1
);
854 basic_block bb2g
= find_group (bb2
);
856 /* ??? I don't have a place for the rank field. OK. Lets go w/o it,
857 this code is unlikely going to be performance problem anyway. */
864 /* This function searches all of the edges in the program flow graph, and puts
865 as many bad edges as possible onto the spanning tree. Bad edges include
866 abnormals edges, which can't be instrumented at the moment. Since it is
867 possible for fake edges to form an cycle, we will have to develop some
868 better way in the future. Also put critical edges to the tree, since they
869 are more expensive to instrument. */
872 find_spanning_tree (el
)
873 struct edge_list
*el
;
876 int num_edges
= NUM_EDGES (el
);
878 /* We use aux field for standard union-find algorithm. */
879 EXIT_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
;
880 ENTRY_BLOCK_PTR
->aux
= ENTRY_BLOCK_PTR
;
881 for (i
= 0; i
< n_basic_blocks
; i
++)
882 BASIC_BLOCK (i
)->aux
= BASIC_BLOCK (i
);
884 /* Add fake edge exit to entry we can't instrument. */
885 union_groups (EXIT_BLOCK_PTR
, ENTRY_BLOCK_PTR
);
887 /* First add all abnormal edges to the tree unless they form an cycle. */
888 for (i
= 0; i
< num_edges
; i
++)
890 edge e
= INDEX_EDGE (el
, i
);
891 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_ABNORMAL_CALL
| EDGE_FAKE
))
892 && !EDGE_INFO (e
)->ignore
893 && (find_group (e
->src
) != find_group (e
->dest
)))
895 EDGE_INFO (e
)->on_tree
= 1;
896 union_groups (e
->src
, e
->dest
);
900 /* Now insert all critical edges to the tree unless they form an cycle. */
901 for (i
= 0; i
< num_edges
; i
++)
903 edge e
= INDEX_EDGE (el
, i
);
904 if ((EDGE_CRITICAL_P (e
))
905 && !EDGE_INFO (e
)->ignore
906 && (find_group (e
->src
) != find_group (e
->dest
)))
908 EDGE_INFO (e
)->on_tree
= 1;
909 union_groups (e
->src
, e
->dest
);
913 /* And now the rest. */
914 for (i
= 0; i
< num_edges
; i
++)
916 edge e
= INDEX_EDGE (el
, i
);
917 if (find_group (e
->src
) != find_group (e
->dest
)
918 && !EDGE_INFO (e
)->ignore
)
920 EDGE_INFO (e
)->on_tree
= 1;
921 union_groups (e
->src
, e
->dest
);
925 EXIT_BLOCK_PTR
->aux
= NULL
;
926 ENTRY_BLOCK_PTR
->aux
= NULL
;
927 for (i
= 0; i
< n_basic_blocks
; i
++)
928 BASIC_BLOCK (i
)->aux
= NULL
;
931 /* Perform file-level initialization for branch-prob processing. */
934 init_branch_prob (filename
)
935 const char *filename
;
940 if (flag_test_coverage
)
942 int len
= strlen (filename
);
943 char *data_file
, *bbg_file_name
;
945 /* Open an output file for the basic block/line number map. */
946 data_file
= (char *) alloca (len
+ 4);
947 strcpy (data_file
, filename
);
948 strip_off_ending (data_file
, len
);
949 strcat (data_file
, ".bb");
950 if ((bb_file
= fopen (data_file
, "wb")) == 0)
951 fatal_io_error ("can't open %s", data_file
);
953 /* Open an output file for the program flow graph. */
954 bbg_file_name
= (char *) alloca (len
+ 5);
955 strcpy (bbg_file_name
, filename
);
956 strip_off_ending (bbg_file_name
, len
);
957 strcat (bbg_file_name
, ".bbg");
958 if ((bbg_file
= fopen (bbg_file_name
, "wb")) == 0)
959 fatal_io_error ("can't open %s", bbg_file_name
);
961 /* Initialize to zero, to ensure that the first file name will be
962 written to the .bb file. */
963 last_bb_file_name
= 0;
966 if (flag_branch_probabilities
)
970 len
= strlen (filename
);
971 da_file_name
= (char *) alloca (len
+ 4);
972 strcpy (da_file_name
, filename
);
973 strip_off_ending (da_file_name
, len
);
974 strcat (da_file_name
, ".da");
975 if ((da_file
= fopen (da_file_name
, "rb")) == 0)
976 warning ("file %s not found, execution counts assumed to be zero",
979 /* The first word in the .da file gives the number of instrumented
980 edges, which is not needed for our purposes. */
983 __read_long (&len
, da_file
, 8);
986 if (profile_arc_flag
)
987 init_edge_profiler ();
989 total_num_blocks
= 0;
991 total_num_edges_ignored
= 0;
992 total_num_edges_instrumented
= 0;
993 total_num_blocks_created
= 0;
994 total_num_passes
= 0;
995 total_num_times_called
= 0;
996 total_num_branches
= 0;
997 total_num_never_executed
= 0;
998 for (i
= 0; i
< 20; i
++)
999 total_hist_br_prob
[i
] = 0;
1002 /* Performs file-level cleanup after branch-prob processing
1008 if (flag_test_coverage
)
1014 if (flag_branch_probabilities
)
1019 /* This seems slightly dangerous, as it presumes the EOF
1020 flag will not be set until an attempt is made to read
1021 past the end of the file. */
1023 error (".da file contents exhausted too early");
1024 /* Should be at end of file now. */
1025 if (__read_long (&temp
, da_file
, 8) == 0)
1026 error (".da file contents not exhausted");
1033 fprintf (rtl_dump_file
, "\n");
1034 fprintf (rtl_dump_file
, "Total number of blocks: %d\n",
1036 fprintf (rtl_dump_file
, "Total number of edges: %d\n", total_num_edges
);
1037 fprintf (rtl_dump_file
, "Total number of ignored edges: %d\n",
1038 total_num_edges_ignored
);
1039 fprintf (rtl_dump_file
, "Total number of instrumented edges: %d\n",
1040 total_num_edges_instrumented
);
1041 fprintf (rtl_dump_file
, "Total number of blocks created: %d\n",
1042 total_num_blocks_created
);
1043 fprintf (rtl_dump_file
, "Total number of graph solution passes: %d\n",
1045 if (total_num_times_called
!= 0)
1046 fprintf (rtl_dump_file
, "Average number of graph solution passes: %d\n",
1047 (total_num_passes
+ (total_num_times_called
>> 1))
1048 / total_num_times_called
);
1049 fprintf (rtl_dump_file
, "Total number of branches: %d\n",
1050 total_num_branches
);
1051 fprintf (rtl_dump_file
, "Total number of branches never executed: %d\n",
1052 total_num_never_executed
);
1053 if (total_num_branches
)
1057 for (i
= 0; i
< 10; i
++)
1058 fprintf (rtl_dump_file
, "%d%% branches in range %d-%d%%\n",
1059 (total_hist_br_prob
[i
] + total_hist_br_prob
[19-i
]) * 100
1060 / total_num_branches
, 5*i
, 5*i
+5);
1065 /* The label used by the edge profiling code. */
1067 static rtx profiler_label
;
1069 /* Initialize the profiler_label. */
1072 init_edge_profiler ()
1074 /* Generate and save a copy of this so it can be shared. */
1076 ASM_GENERATE_INTERNAL_LABEL (buf
, "LPBX", 2);
1077 profiler_label
= gen_rtx_SYMBOL_REF (Pmode
, ggc_strdup (buf
));
1078 ggc_add_rtx_root (&profiler_label
, 1);
1081 /* Output instructions as RTL to increment the edge execution count. */
1084 gen_edge_profiler (edgeno
)
1087 enum machine_mode mode
= mode_for_size (GCOV_TYPE_SIZE
, MODE_INT
, 0);
1093 tmp
= force_reg (Pmode
, profiler_label
);
1094 tmp
= plus_constant (tmp
, GCOV_TYPE_SIZE
/ BITS_PER_UNIT
* edgeno
);
1095 mem_ref
= validize_mem (gen_rtx_MEM (mode
, tmp
));
1097 tmp
= expand_simple_binop (mode
, PLUS
, mem_ref
, const1_rtx
,
1098 mem_ref
, 0, OPTAB_WIDEN
);
1101 emit_move_insn (copy_rtx (mem_ref
), tmp
);
1103 sequence
= gen_sequence ();
1108 /* Output code for a constructor that will invoke __bb_init_func, if
1109 this has not already been done. */
1112 output_func_start_profiler ()
1114 tree fnname
, fndecl
;
1117 const char *cfnname
;
1119 enum machine_mode mode
= mode_for_size (GCOV_TYPE_SIZE
, MODE_INT
, 0);
1120 int save_flag_inline_functions
= flag_inline_functions
;
1121 int save_flag_test_coverage
= flag_test_coverage
;
1122 int save_profile_arc_flag
= profile_arc_flag
;
1123 int save_flag_branch_probabilities
= flag_branch_probabilities
;
1125 /* It's either already been output, or we don't need it because we're
1126 not doing profile-edges. */
1127 if (! need_func_profiler
)
1130 need_func_profiler
= 0;
1132 /* Synthesize a constructor function to invoke __bb_init_func with a
1133 pointer to this object file's profile block. */
1135 /* Try and make a unique name given the "file function name".
1137 And no, I don't like this either. */
1139 fnname
= get_file_function_name ('I');
1140 cfnname
= IDENTIFIER_POINTER (fnname
);
1141 name
= concat (cfnname
, "GCOV", NULL
);
1142 fnname
= get_identifier (name
);
1145 fndecl
= build_decl (FUNCTION_DECL
, fnname
,
1146 build_function_type (void_type_node
, NULL_TREE
));
1147 DECL_EXTERNAL (fndecl
) = 0;
1149 /* It can be a static function as long as collect2 does not have
1150 to scan the object file to find its ctor/dtor routine. */
1151 TREE_PUBLIC (fndecl
) = ! targetm
.have_ctors_dtors
;
1153 TREE_USED (fndecl
) = 1;
1155 DECL_RESULT (fndecl
) = build_decl (RESULT_DECL
, NULL_TREE
, void_type_node
);
1157 fndecl
= (*lang_hooks
.decls
.pushdecl
) (fndecl
);
1158 rest_of_decl_compilation (fndecl
, 0, 1, 0);
1159 announce_function (fndecl
);
1160 current_function_decl
= fndecl
;
1161 DECL_INITIAL (fndecl
) = error_mark_node
;
1162 make_decl_rtl (fndecl
, NULL
);
1163 init_function_start (fndecl
, input_filename
, lineno
);
1164 (*lang_hooks
.decls
.pushlevel
) (0);
1165 expand_function_start (fndecl
, 0);
1167 /* Actually generate the code to call __bb_init_func. */
1168 ASM_GENERATE_INTERNAL_LABEL (buf
, "LPBX", 0);
1169 table_address
= force_reg (Pmode
,
1170 gen_rtx_SYMBOL_REF (Pmode
, ggc_strdup (buf
)));
1171 emit_library_call (gen_rtx_SYMBOL_REF (Pmode
, "__bb_init_func"), LCT_NORMAL
,
1172 mode
, 1, table_address
, Pmode
);
1174 expand_function_end (input_filename
, lineno
, 0);
1175 (*lang_hooks
.decls
.poplevel
) (1, 0, 1);
1177 /* Since fndecl isn't in the list of globals, it would never be emitted
1178 when it's considered to be 'safe' for inlining, so turn off
1179 flag_inline_functions. */
1180 flag_inline_functions
= 0;
1182 /* Don't instrument the function that turns on instrumentation. Which
1183 is also handy since we'd get silly warnings about not consuming all
1184 of our da_file input. */
1185 flag_test_coverage
= 0;
1186 profile_arc_flag
= 0;
1187 flag_branch_probabilities
= 0;
1189 rest_of_compilation (fndecl
);
1191 /* Reset flag_inline_functions to its original value. */
1192 flag_inline_functions
= save_flag_inline_functions
;
1193 flag_test_coverage
= save_flag_test_coverage
;
1194 profile_arc_flag
= save_profile_arc_flag
;
1195 flag_branch_probabilities
= save_flag_branch_probabilities
;
1198 fflush (asm_out_file
);
1199 current_function_decl
= NULL_TREE
;
1201 if (targetm
.have_ctors_dtors
)
1202 (* targetm
.asm_out
.constructor
) (XEXP (DECL_RTL (fndecl
), 0),
1203 DEFAULT_INIT_PRIORITY
);