1 /* basic_blocks.c  -  Basic-block level related code: reading/writing
2    of basic-block info to/from gmon.out; computing and formatting of
3    basic-block related statistics.
4 
5    Copyright (C) 1999-2020 Free Software Foundation, Inc.
6 
7    This file is part of GNU Binutils.
8 
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3 of the License, or
12    (at your option) any later version.
13 
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18 
19    You should have received a copy of the GNU General Public License
20    along with this program; if not, write to the Free Software
21    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
22    02110-1301, USA.  */
23 
24 #include "gprof.h"
25 #include "libiberty.h"
26 #include "filenames.h"
27 #include "basic_blocks.h"
28 #include "corefile.h"
29 #include "gmon_io.h"
30 #include "gmon_out.h"
31 #include "search_list.h"
32 #include "source.h"
33 #include "symtab.h"
34 #include "sym_ids.h"
35 
36 static int cmp_bb (const PTR, const PTR);
37 static int cmp_ncalls (const PTR, const PTR);
38 static void fskip_string (FILE *);
39 static void annotate_with_count (char *, unsigned int, int, PTR);
40 
41 /* Default option values:  */
42 bfd_boolean bb_annotate_all_lines = FALSE;
43 unsigned long bb_min_calls = 1;
44 int bb_table_length = 10;
45 
46 /* Variables used to compute annotated source listing stats:  */
47 static long num_executable_lines;
48 static long num_lines_executed;
49 
50 
51 /* Helper for sorting.  Compares two symbols and returns result
52    such that sorting will be increasing according to filename, line
53    number, and address (in that order).  */
54 
55 static int
56 cmp_bb (const PTR lp, const PTR rp)
57 {
58   int r;
59   const Sym *left = *(const Sym **) lp;
60   const Sym *right = *(const Sym **) rp;
61 
62   if (left->file && right->file)
63     {
64       r = filename_cmp (left->file->name, right->file->name);
65 
66       if (r)
67 	return r;
68 
69       if (left->line_num != right->line_num)
70 	return left->line_num - right->line_num;
71     }
72 
73   if (left->addr < right->addr)
74     return -1;
75   else if (left->addr > right->addr)
76     return 1;
77   else
78     return 0;
79 }
80 
81 
82 /* Helper for sorting.  Order basic blocks in decreasing number of
83    calls, ties are broken in increasing order of line numbers.  */
84 static int
85 cmp_ncalls (const PTR lp, const PTR rp)
86 {
87   const Sym *left = *(const Sym **) lp;
88   const Sym *right = *(const Sym **) rp;
89 
90   if (!left)
91     return 1;
92   else if (!right)
93     return -1;
94 
95   if (left->ncalls < right->ncalls)
96     return 1;
97   else if (left->ncalls > right->ncalls)
98     return -1;
99 
100   return left->line_num - right->line_num;
101 }
102 
103 /* Skip over variable length string.  */
104 static void
105 fskip_string (FILE *fp)
106 {
107   int ch;
108 
109   while ((ch = fgetc (fp)) != EOF)
110     {
111       if (ch == '\0')
112 	break;
113     }
114 }
115 
116 /* Read a basic-block record from file IFP.  FILENAME is the name
117    of file IFP and is provided for formatting error-messages only.  */
118 
119 void
120 bb_read_rec (FILE *ifp, const char *filename)
121 {
122   unsigned int nblocks, b;
123   bfd_vma addr, ncalls;
124   Sym *sym;
125 
126   if (gmon_io_read_32 (ifp, &nblocks))
127     {
128       fprintf (stderr, _("%s: %s: unexpected end of file\n"),
129 	       whoami, filename);
130       done (1);
131     }
132 
133   nblocks = bfd_get_32 (core_bfd, (bfd_byte *) & nblocks);
134   if (gmon_file_version == 0)
135     fskip_string (ifp);
136 
137   for (b = 0; b < nblocks; ++b)
138     {
139       if (gmon_file_version == 0)
140 	{
141 	  int line_num;
142 
143 	  /* Version 0 had lots of extra stuff that we don't
144 	     care about anymore.  */
145 	  if ((fread (&ncalls, sizeof (ncalls), 1, ifp) != 1)
146 	      || (fread (&addr, sizeof (addr), 1, ifp) != 1)
147 	      || (fskip_string (ifp), FALSE)
148 	      || (fskip_string (ifp), FALSE)
149 	      || (fread (&line_num, sizeof (line_num), 1, ifp) != 1))
150 	    {
151 	      perror (filename);
152 	      done (1);
153 	    }
154 	}
155       else if (gmon_io_read_vma (ifp, &addr)
156 	       || gmon_io_read_vma (ifp, &ncalls))
157 	{
158 	  perror (filename);
159 	  done (1);
160 	}
161 
162       /* Basic-block execution counts are meaningful only if we're
163 	 profiling at the line-by-line level:  */
164       if (line_granularity)
165 	{
166 	  sym = sym_lookup (&symtab, addr);
167 
168 	  if (sym)
169 	    {
170 	      int i;
171 
172 	      DBG (BBDEBUG,
173 		   printf ("[bb_read_rec] 0x%lx->0x%lx (%s:%d) cnt=%lu\n",
174 			   (unsigned long) addr, (unsigned long) sym->addr,
175 			   sym->name, sym->line_num, (unsigned long) ncalls));
176 
177 	      for (i = 0; i < NBBS; i++)
178 		{
179 		  if (! sym->bb_addr[i] || sym->bb_addr[i] == addr)
180 		    {
181 		      sym->bb_addr[i] = addr;
182 		      sym->bb_calls[i] += ncalls;
183 		      break;
184 		    }
185 		}
186 	    }
187 	}
188       else
189 	{
190 	  static bfd_boolean user_warned = FALSE;
191 
192 	  if (!user_warned)
193 	    {
194 	      user_warned = TRUE;
195 	      fprintf (stderr,
196   _("%s: warning: ignoring basic-block exec counts (use -l or --line)\n"),
197 		       whoami);
198 	    }
199 	}
200     }
201   return;
202 }
203 
204 /* Write all basic-blocks with non-zero counts to file OFP.  FILENAME
205    is the name of OFP and is provided for producing error-messages
206    only.  */
207 void
208 bb_write_blocks (FILE *ofp, const char *filename)
209 {
210   unsigned int nblocks = 0;
211   Sym *sym;
212   int i;
213 
214   /* Count how many non-zero blocks with have:  */
215   for (sym = symtab.base; sym < symtab.limit; ++sym)
216     {
217       for (i = 0; i < NBBS && sym->bb_addr[i]; i++)
218 	;
219       nblocks += i;
220     }
221 
222   /* Write header:  */
223   if (gmon_io_write_8 (ofp, GMON_TAG_BB_COUNT)
224       || gmon_io_write_32 (ofp, nblocks))
225     {
226       perror (filename);
227       done (1);
228     }
229 
230   /* Write counts:  */
231   for (sym = symtab.base; sym < symtab.limit; ++sym)
232     {
233       for (i = 0; i < NBBS && sym->bb_addr[i]; i++)
234 	{
235 	  if (gmon_io_write_vma (ofp, sym->bb_addr[i])
236 	      || gmon_io_write_vma (ofp, (bfd_vma) sym->bb_calls[i]))
237 	    {
238 	      perror (filename);
239 	      done (1);
240 	    }
241 	}
242     }
243 }
244 
245 /* Output basic-block statistics in a format that is easily parseable.
246    Current the format is:
247 
248 	<filename>:<line-number>: (<function-name>:<bb-addr): <ncalls>  */
249 
250 void
251 print_exec_counts (void)
252 {
253   Sym **sorted_bbs, *sym;
254   unsigned int i, j, len;
255 
256   if (first_output)
257     first_output = FALSE;
258   else
259     printf ("\f\n");
260 
261   /* Sort basic-blocks according to function name and line number:  */
262   sorted_bbs = (Sym **) xmalloc (symtab.len * sizeof (sorted_bbs[0]));
263   len = 0;
264 
265   for (sym = symtab.base; sym < symtab.limit; ++sym)
266     {
267       /* Accept symbol if it's in the INCL_EXEC table
268 	 or there is no INCL_EXEC table
269 	 and it does not appear in the EXCL_EXEC table.  */
270       if (sym_lookup (&syms[INCL_EXEC], sym->addr)
271 	  || (syms[INCL_EXEC].len == 0
272 	      && !sym_lookup (&syms[EXCL_EXEC], sym->addr)))
273 	{
274 	  sorted_bbs[len++] = sym;
275 	}
276     }
277 
278   qsort (sorted_bbs, len, sizeof (sorted_bbs[0]), cmp_bb);
279 
280   /* Output basic-blocks:  */
281 
282   for (i = 0; i < len; ++i)
283     {
284       sym = sorted_bbs [i];
285 
286       if (sym->ncalls > 0 || ! ignore_zeros)
287 	{
288 	  /* FIXME: This only works if bfd_vma is unsigned long.  */
289 	  printf (_("%s:%d: (%s:0x%lx) %lu executions\n"),
290 		  sym->file ? sym->file->name : _("<unknown>"), sym->line_num,
291 		  sym->name, (unsigned long) sym->addr, sym->ncalls);
292 	}
293 
294       for (j = 0; j < NBBS && sym->bb_addr[j]; j ++)
295 	{
296 	  if (sym->bb_calls[j] > 0 || ! ignore_zeros)
297 	    {
298 	      /* FIXME: This only works if bfd_vma is unsigned long.  */
299 	      printf (_("%s:%d: (%s:0x%lx) %lu executions\n"),
300 		      sym->file ? sym->file->name : _("<unknown>"), sym->line_num,
301 		      sym->name, (unsigned long) sym->bb_addr[j],
302 		      sym->bb_calls[j]);
303 	    }
304 	}
305     }
306   free (sorted_bbs);
307 }
308 
309 /* Helper for bb_annotated_source: format annotation containing
310    number of line executions.  Depends on being called on each
311    line of a file in sequential order.
312 
313    Global variable bb_annotate_all_lines enables execution count
314    compression (counts are suppressed if identical to the last one)
315    and prints counts on all executed lines.  Otherwise, print
316    all basic-block execution counts exactly once on the line
317    that starts the basic-block.  */
318 
319 static void
320 annotate_with_count (char *buf, unsigned int width, int line_num, PTR arg)
321 {
322   Source_File *sf = (Source_File *) arg;
323   Sym *b;
324   unsigned int i;
325   static unsigned long last_count;
326   unsigned long last_print = (unsigned long) -1;
327 
328   b = NULL;
329 
330   if (line_num <= sf->num_lines)
331     b = (Sym *) sf->line[line_num - 1];
332 
333   if (!b)
334     {
335       for (i = 0; i < width; i++)
336 	buf[i] = ' ';
337       buf[width] = '\0';
338     }
339   else
340     {
341       char tmpbuf[NBBS * 30];
342       char *p;
343       unsigned long ncalls;
344       int ncalls_set;
345       unsigned int len;
346 
347       ++num_executable_lines;
348 
349       p = tmpbuf;
350       *p = '\0';
351 
352       ncalls = 0;
353       ncalls_set = 0;
354 
355       /* If this is a function entry point, label the line no matter what.
356 	 Otherwise, we're in the middle of a function, so check to see
357 	 if the first basic-block address is larger than the starting
358 	 address of the line.  If so, then this line begins with a
359 	 a portion of the previous basic-block, so print that prior
360 	 execution count (if bb_annotate_all_lines is set).  */
361       if (b->is_func)
362 	{
363 	  sprintf (p, "%lu", b->ncalls);
364 	  p += strlen (p);
365 	  last_count = b->ncalls;
366 	  last_print = last_count;
367 	  ncalls = b->ncalls;
368 	  ncalls_set = 1;
369 	}
370       else if (bb_annotate_all_lines
371 	       && b->bb_addr[0] && b->bb_addr[0] > b->addr)
372 	{
373 	  sprintf (p, "%lu", last_count);
374 	  p += strlen (p);
375 	  last_print = last_count;
376 	  ncalls = last_count;
377 	  ncalls_set = 1;
378 	}
379 
380       /* Loop through all of this line's basic-blocks.  For each one,
381 	 update last_count, then compress sequential identical counts
382 	 (if bb_annotate_all_lines) and print the execution count.  */
383 
384       for (i = 0; i < NBBS && b->bb_addr[i]; i++)
385 	{
386 	  last_count = b->bb_calls[i];
387 	  if (! ncalls_set)
388 	    {
389 	      ncalls = 0;
390 	      ncalls_set = 1;
391 	    }
392 	  ncalls += last_count;
393 
394 	  if (bb_annotate_all_lines && last_count == last_print)
395 	    continue;
396 
397 	  if (p > tmpbuf)
398 	    *p++ = ',';
399 	  sprintf (p, "%lu", last_count);
400 	  p += strlen (p);
401 
402 	  last_print = last_count;
403 	}
404 
405       /* We're done.  If nothing has been printed on this line,
406 	 print the last execution count (bb_annotate_all_lines),
407 	 which could be from either a previous line (if there were
408 	 no BBs on this line), or from this line (if all our BB
409 	 counts were compressed out because they were identical).  */
410 
411       if (bb_annotate_all_lines && p == tmpbuf)
412 	{
413 	  sprintf (p, "%lu", last_count);
414 	  p += strlen (p);
415 	  ncalls = last_count;
416 	  ncalls_set = 1;
417 	}
418 
419       if (! ncalls_set)
420 	{
421 	  unsigned int c;
422 
423 	  for (c = 0; c < width; c++)
424 	    buf[c] = ' ';
425 	  buf[width] = '\0';
426 	  return;
427 	}
428 
429       ++num_lines_executed;
430 
431       if (ncalls < bb_min_calls)
432 	{
433 	  strcpy (tmpbuf, "#####");
434 	  p = tmpbuf + 5;
435 	}
436 
437       strcpy (p, " -> ");
438       p += 4;
439 
440       len = p - tmpbuf;
441       if (len >= width)
442 	{
443 	  strncpy (buf, tmpbuf, width);
444 	  buf[width] = '\0';
445 	}
446       else
447 	{
448 	  unsigned int c;
449 
450 	  strcpy (buf + width - len, tmpbuf);
451 	  for (c = 0; c < width - len; ++c)
452 	    buf[c] = ' ';
453 	}
454     }
455 }
456 
457 /* Annotate the files named in SOURCE_FILES with basic-block statistics
458    (execution counts).  After each source files, a few statistics
459    regarding that source file are printed.  */
460 
461 void
462 print_annotated_source (void)
463 {
464   Sym *sym, *line_stats, *new_line;
465   Source_File *sf;
466   int i, table_len;
467   FILE *ofp;
468 
469   /* Find maximum line number for each source file that user is
470      interested in:  */
471   for (sym = symtab.base; sym < symtab.limit; ++sym)
472     {
473       /* Accept symbol if it's file is known, its line number is
474 	 bigger than anything we have seen for that file so far and
475 	 if it's in the INCL_ANNO table or there is no INCL_ANNO
476 	 table and it does not appear in the EXCL_ANNO table.  */
477       if (sym->file && sym->line_num > sym->file->num_lines
478 	  && (sym_lookup (&syms[INCL_ANNO], sym->addr)
479 	      || (syms[INCL_ANNO].len == 0
480 		  && !sym_lookup (&syms[EXCL_ANNO], sym->addr))))
481 	{
482 	  sym->file->num_lines = sym->line_num;
483 	}
484     }
485 
486   /* Allocate line descriptors:  */
487   for (sf = first_src_file; sf; sf = sf->next)
488     {
489       if (sf->num_lines > 0)
490 	{
491 	  sf->line = (void **) xmalloc (sf->num_lines * sizeof (sf->line[0]));
492 	  memset (sf->line, 0, sf->num_lines * sizeof (sf->line[0]));
493 	}
494     }
495 
496   /* Count executions per line:  */
497   for (sym = symtab.base; sym < symtab.limit; ++sym)
498     {
499       if (sym->file && sym->file->num_lines
500 	  && (sym_lookup (&syms[INCL_ANNO], sym->addr)
501 	      || (syms[INCL_ANNO].len == 0
502 		  && !sym_lookup (&syms[EXCL_ANNO], sym->addr))))
503 	{
504 	  sym->file->ncalls += sym->ncalls;
505 	  line_stats = (Sym *) sym->file->line[sym->line_num - 1];
506 
507 	  if (!line_stats)
508 	    {
509 	      /* Common case has at most one basic-block per source line:  */
510 	      sym->file->line[sym->line_num - 1] = sym;
511 	    }
512 	  else if (!line_stats->addr)
513 	    {
514 	      /* sym is the 3rd .. nth basic block for this line:  */
515 	      line_stats->ncalls += sym->ncalls;
516 	    }
517 	  else
518 	    {
519 	      /* sym is the second basic block for this line.  */
520 	      new_line = (Sym *) xmalloc (sizeof (*new_line));
521 	      *new_line = *line_stats;
522 	      new_line->addr = 0;
523 	      new_line->ncalls += sym->ncalls;
524 	      sym->file->line[sym->line_num - 1] = new_line;
525 	    }
526 	}
527     }
528 
529   /* Plod over source files, annotating them:  */
530   for (sf = first_src_file; sf; sf = sf->next)
531     {
532       if (!sf->num_lines || (ignore_zeros && sf->ncalls == 0))
533 	continue;
534 
535       num_executable_lines = num_lines_executed = 0;
536 
537       ofp = annotate_source (sf, 16, annotate_with_count, sf);
538       if (!ofp)
539 	continue;
540 
541       if (bb_table_length > 0)
542 	{
543 	  fprintf (ofp, _("\n\nTop %d Lines:\n\n     Line      Count\n\n"),
544 		   bb_table_length);
545 
546 	  /* Abuse line arrays---it's not needed anymore:  */
547 	  qsort (sf->line, sf->num_lines, sizeof (sf->line[0]), cmp_ncalls);
548 	  table_len = bb_table_length;
549 
550 	  if (table_len > sf->num_lines)
551 	    table_len = sf->num_lines;
552 
553 	  for (i = 0; i < table_len; ++i)
554 	    {
555 	      sym = (Sym *) sf->line[i];
556 
557 	      if (!sym || sym->ncalls == 0)
558 		  break;
559 
560 	      fprintf (ofp, "%9d %10lu\n", sym->line_num, sym->ncalls);
561 	    }
562 	}
563 
564       free (sf->line);
565       sf->line = 0;
566 
567       fprintf (ofp, _("\nExecution Summary:\n\n"));
568       fprintf (ofp, _("%9ld   Executable lines in this file\n"),
569 	       num_executable_lines);
570       fprintf (ofp, _("%9ld   Lines executed\n"), num_lines_executed);
571       fprintf (ofp, _("%9.2f   Percent of the file executed\n"),
572 	       num_executable_lines
573 	       ? 100.0 * num_lines_executed / (double) num_executable_lines
574 	       : 100.0);
575       fprintf (ofp, _("\n%9lu   Total number of line executions\n"),
576 	       sf->ncalls);
577       fprintf (ofp, _("%9.2f   Average executions per line\n"),
578 	       num_executable_lines
579 	       ? (double) sf->ncalls / (double) num_executable_lines
580 	       : 0.0);
581 
582       if (ofp != stdout)
583 	fclose (ofp);
584     }
585 }
586