libgcc/libgcov-driver.c

   1 /* Routines required for instrumenting a program.  */
   2 /* Compile this one with gcc.  */
   3 /* Copyright (C) 1989-2020 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgcov.h"
  27 #include "gcov-io.h"
  28
  29 #if defined(inhibit_libc)
  30 /* If libc and its header files are not available, provide dummy functions.  */
  31
  32 #if defined(L_gcov)
  33 void __gcov_init (struct gcov_info *p __attribute__ ((unused))) {}
  34 #endif
  35
  36 #else /* inhibit_libc */
  37
  38 #include <string.h>
  39 #if GCOV_LOCKED
  40 #include <fcntl.h>
  41 #include <errno.h>
  42 #include <sys/stat.h>
  43 #endif
  44
  45 #ifdef L_gcov
  46
  47 /* A utility function for outputting errors.  */
  48 static int gcov_error (const char *, ...);
  49
  50 #if !IN_GCOV_TOOL
  51 static void gcov_error_exit (void);
  52 #endif
  53
  54 #include "gcov-io.c"
  55
  56 #define GCOV_PROF_PREFIX "libgcov profiling error:%s:"
  57
  58 struct gcov_fn_buffer
  59 {
  60   struct gcov_fn_buffer *next;
  61   unsigned fn_ix;
  62   struct gcov_fn_info info;
  63   /* note gcov_fn_info ends in a trailing array.  */
  64 };
  65
  66 struct gcov_summary_buffer
  67 {
  68   struct gcov_summary_buffer *next;
  69   struct gcov_summary summary;
  70 };
  71
  72 /* A struct that bundles all the related information about the
  73    gcda filename.  */
  74
  75 struct gcov_filename
  76 {
  77   char *filename;  /* filename buffer */
  78   int strip; /* leading chars to strip from filename */
  79   char *prefix; /* prefix string */
  80 };
  81
  82 static struct gcov_fn_buffer *
  83 free_fn_data (const struct gcov_info *gi_ptr, struct gcov_fn_buffer *buffer,
  84               unsigned limit)
  85 {
  86   struct gcov_fn_buffer *next;
  87   unsigned ix, n_ctr = 0;
  88
  89   if (!buffer)
  90     return 0;
  91   next = buffer->next;
  92
  93   for (ix = 0; ix != limit; ix++)
  94     if (gi_ptr->merge[ix])
  95       free (buffer->info.ctrs[n_ctr++].values);
  96   free (buffer);
  97   return next;
  98 }
  99
 100 static struct gcov_fn_buffer **
 101 buffer_fn_data (const char *filename, const struct gcov_info *gi_ptr,
 102                 struct gcov_fn_buffer **end_ptr, unsigned fn_ix)
 103 {
 104   unsigned n_ctrs = 0, ix = 0;
 105   struct gcov_fn_buffer *fn_buffer;
 106   unsigned len;
 107
 108   for (ix = GCOV_COUNTERS; ix--;)
 109     if (gi_ptr->merge[ix])
 110       n_ctrs++;
 111
 112   len = sizeof (*fn_buffer) + sizeof (fn_buffer->info.ctrs[0]) * n_ctrs;
 113   fn_buffer = (struct gcov_fn_buffer *) xmalloc (len);
 114
 115   if (!fn_buffer)
 116     goto fail;
 117
 118   fn_buffer->next = 0;
 119   fn_buffer->fn_ix = fn_ix;
 120   fn_buffer->info.ident = gcov_read_unsigned ();
 121   fn_buffer->info.lineno_checksum = gcov_read_unsigned ();
 122   fn_buffer->info.cfg_checksum = gcov_read_unsigned ();
 123
 124   for (n_ctrs = ix = 0; ix != GCOV_COUNTERS; ix++)
 125     {
 126       gcov_unsigned_t length;
 127       gcov_type *values;
 128
 129       if (!gi_ptr->merge[ix])
 130         continue;
 131
 132       if (gcov_read_unsigned () != GCOV_TAG_FOR_COUNTER (ix))
 133         {
 134           len = 0;
 135           goto fail;
 136         }
 137
 138       length = GCOV_TAG_COUNTER_NUM (gcov_read_unsigned ());
 139       len = length * sizeof (gcov_type);
 140       values = (gcov_type *) xmalloc (len);
 141       if (!values)
 142         goto fail;
 143
 144       fn_buffer->info.ctrs[n_ctrs].num = length;
 145       fn_buffer->info.ctrs[n_ctrs].values = values;
 146
 147       while (length--)
 148         *values++ = gcov_read_counter ();
 149       n_ctrs++;
 150     }
 151
 152   *end_ptr = fn_buffer;
 153   return &fn_buffer->next;
 154
 155 fail:
 156   gcov_error (GCOV_PROF_PREFIX "Function %u %s %u \n", filename, fn_ix,
 157               len ? "cannot allocate" : "counter mismatch", len ? len : ix);
 158
 159   return (struct gcov_fn_buffer **)free_fn_data (gi_ptr, fn_buffer, ix);
 160 }
 161
 162 /* Convert VERSION into a string description and return the it.
 163    BUFFER is used for storage of the string.  The code should be
 164    aligned wit gcov-iov.c.  */
 165
 166 static char *
 167 gcov_version_string (char *buffer, char version[4])
 168 {
 169   if (version[0] < 'A' || version[0] > 'Z'
 170       || version[1] < '0' || version[1] > '9'
 171       || version[2] < '0' || version[2] > '9')
 172     sprintf (buffer, "(unknown)");
 173   else
 174     {
 175       unsigned major = 10 * (version[0] - 'A') + (version[1] - '0');
 176       unsigned minor = version[2] - '0';
 177       sprintf (buffer, "%u.%u (%s)", major, minor,
 178                version[3] == '*' ? "release" : "experimental");
 179     }
 180   return buffer;
 181 }
 182
 183 /* Check if VERSION of the info block PTR matches libgcov one.
 184    Return 1 on success, or zero in case of versions mismatch.
 185    If FILENAME is not NULL, its value used for reporting purposes
 186    instead of value from the info block.  */
 187
 188 static int
 189 gcov_version (struct gcov_info *ptr, gcov_unsigned_t version,
 190               const char *filename)
 191 {
 192   if (version != GCOV_VERSION)
 193     {
 194       char v[4], e[4];
 195       char version_string[128], expected_string[128];
 196
 197       GCOV_UNSIGNED2STRING (v, version);
 198       GCOV_UNSIGNED2STRING (e, GCOV_VERSION);
 199
 200       gcov_error (GCOV_PROF_PREFIX "Version mismatch - expected %s (%.4s) "
 201                   "got %s (%.4s)\n",
 202                   filename? filename : ptr->filename,
 203                   gcov_version_string (expected_string, e), e,
 204                   gcov_version_string (version_string, v), v);
 205       return 0;
 206     }
 207   return 1;
 208 }
 209
 210 /* buffer for the fn_data from another program.  */
 211 static struct gcov_fn_buffer *fn_buffer;
 212
 213 /* Including system dependent components. */
 214 #include "libgcov-driver-system.c"
 215
 216 /* This function merges counters in GI_PTR to an existing gcda file.
 217    Return 0 on success.
 218    Return -1 on error. In this case, caller will goto read_fatal.  */
 219
 220 static int
 221 merge_one_data (const char *filename,
 222                 struct gcov_info *gi_ptr,
 223                 struct gcov_summary *summary)
 224 {
 225   gcov_unsigned_t tag, length;
 226   unsigned t_ix;
 227   int f_ix = -1;
 228   int error = 0;
 229   struct gcov_fn_buffer **fn_tail = &fn_buffer;
 230
 231   length = gcov_read_unsigned ();
 232   if (!gcov_version (gi_ptr, length, filename))
 233     return -1;
 234
 235   length = gcov_read_unsigned ();
 236   if (length != gi_ptr->stamp)
 237     {
 238       /* Read from a different compilation.  Overwrite the file.  */
 239       gcov_error (GCOV_PROF_PREFIX "overwriting an existing profile data "
 240                   "with a different timestamp\n", filename);
 241       return 0;
 242     }
 243
 244   tag = gcov_read_unsigned ();
 245   if (tag != GCOV_TAG_OBJECT_SUMMARY)
 246     goto read_mismatch;
 247   length = gcov_read_unsigned ();
 248   gcc_assert (length > 0);
 249   gcov_read_summary (summary);
 250
 251   tag = gcov_read_unsigned ();
 252   /* Merge execution counts for each function.  */
 253   for (f_ix = 0; (unsigned)f_ix != gi_ptr->n_functions;
 254        f_ix++, tag = gcov_read_unsigned ())
 255     {
 256       const struct gcov_ctr_info *ci_ptr;
 257       const struct gcov_fn_info *gfi_ptr = gi_ptr->functions[f_ix];
 258
 259       if (tag != GCOV_TAG_FUNCTION)
 260         goto read_mismatch;
 261
 262       length = gcov_read_unsigned ();
 263       if (!length)
 264         /* This function did not appear in the other program.
 265            We have nothing to merge.  */
 266         continue;
 267
 268       if (length != GCOV_TAG_FUNCTION_LENGTH)
 269         goto read_mismatch;
 270
 271       if (!gfi_ptr || gfi_ptr->key != gi_ptr)
 272         {
 273           /* This function appears in the other program.  We
 274              need to buffer the information in order to write
 275              it back out -- we'll be inserting data before
 276              this point, so cannot simply keep the data in the
 277              file.  */
 278           fn_tail = buffer_fn_data (filename, gi_ptr, fn_tail, f_ix);
 279           if (!fn_tail)
 280             goto read_mismatch;
 281           continue;
 282         }
 283
 284       length = gcov_read_unsigned ();
 285       if (length != gfi_ptr->ident)
 286         goto read_mismatch;
 287
 288       length = gcov_read_unsigned ();
 289       if (length != gfi_ptr->lineno_checksum)
 290         goto read_mismatch;
 291
 292       length = gcov_read_unsigned ();
 293       if (length != gfi_ptr->cfg_checksum)
 294         goto read_mismatch;
 295
 296       ci_ptr = gfi_ptr->ctrs;
 297       for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
 298         {
 299           gcov_merge_fn merge = gi_ptr->merge[t_ix];
 300
 301           if (!merge)
 302             continue;
 303
 304           tag = gcov_read_unsigned ();
 305           int read_length = (int)gcov_read_unsigned ();
 306           length = abs (read_length);
 307           if (tag != GCOV_TAG_FOR_COUNTER (t_ix)
 308               || (length != GCOV_TAG_COUNTER_LENGTH (ci_ptr->num)
 309                   && t_ix != GCOV_COUNTER_V_TOPN
 310                   && t_ix != GCOV_COUNTER_V_INDIR))
 311             goto read_mismatch;
 312           /* Merging with all zero counters does not make sense.  */
 313           if (read_length > 0)
 314             (*merge) (ci_ptr->values, ci_ptr->num);
 315           ci_ptr++;
 316         }
 317       if ((error = gcov_is_error ()))
 318         goto read_error;
 319     }
 320
 321   if (tag)
 322     {
 323     read_mismatch:;
 324       gcov_error (GCOV_PROF_PREFIX "Merge mismatch for %s %u\n",
 325                   filename, f_ix >= 0 ? "function" : "summary",
 326                   f_ix < 0 ? -1 - f_ix : f_ix);
 327       return -1;
 328     }
 329   return 0;
 330
 331 read_error:
 332   gcov_error (GCOV_PROF_PREFIX "%s merging\n", filename,
 333               error < 0 ? "Overflow": "Error");
 334   return -1;
 335 }
 336
 337 /* Store all TOP N counters where each has a dynamic length.  */
 338
 339 static void
 340 write_top_counters (const struct gcov_ctr_info *ci_ptr,
 341                     unsigned t_ix,
 342                     gcov_unsigned_t n_counts)
 343 {
 344   unsigned counters = n_counts / GCOV_TOPN_MEM_COUNTERS;
 345   gcc_assert (n_counts % GCOV_TOPN_MEM_COUNTERS == 0);
 346   unsigned pair_total = 0;
 347   for (unsigned i = 0; i < counters; i++)
 348     pair_total += ci_ptr->values[GCOV_TOPN_MEM_COUNTERS * i + 1];
 349   unsigned disk_size = GCOV_TOPN_DISK_COUNTERS * counters + 2 * pair_total;
 350   gcov_write_tag_length (GCOV_TAG_FOR_COUNTER (t_ix),
 351                          GCOV_TAG_COUNTER_LENGTH (disk_size));
 352
 353   for (unsigned i = 0; i < counters; i++)
 354     {
 355       gcov_type pair_count = ci_ptr->values[GCOV_TOPN_MEM_COUNTERS * i + 1];
 356       gcov_write_counter (ci_ptr->values[GCOV_TOPN_MEM_COUNTERS * i]);
 357       gcov_write_counter (pair_count);
 358       gcov_type start = ci_ptr->values[GCOV_TOPN_MEM_COUNTERS * i + 2];
 359       for (struct gcov_kvp *node = (struct gcov_kvp *)(intptr_t)start;
 360            node != NULL; node = node->next)
 361         {
 362           gcov_write_counter (node->value);
 363           gcov_write_counter (node->count);
 364         }
 365     }
 366 }
 367
 368 /* Write counters in GI_PTR and the summary in PRG to a gcda file. In
 369    the case of appending to an existing file, SUMMARY_POS will be non-zero.
 370    We will write the file starting from SUMMAY_POS.  */
 371
 372 static void
 373 write_one_data (const struct gcov_info *gi_ptr,
 374                 const struct gcov_summary *prg_p)
 375 {
 376   unsigned f_ix;
 377
 378   gcov_write_tag_length (GCOV_DATA_MAGIC, GCOV_VERSION);
 379   gcov_write_unsigned (gi_ptr->stamp);
 380
 381   /* Generate whole program statistics.  */
 382   gcov_write_summary (GCOV_TAG_OBJECT_SUMMARY, prg_p);
 383
 384   /* Write execution counts for each function.  */
 385   for (f_ix = 0; f_ix != gi_ptr->n_functions; f_ix++)
 386     {
 387       unsigned buffered = 0;
 388       const struct gcov_fn_info *gfi_ptr;
 389       const struct gcov_ctr_info *ci_ptr;
 390       gcov_unsigned_t length;
 391       unsigned t_ix;
 392
 393       if (fn_buffer && fn_buffer->fn_ix == f_ix)
 394         {
 395           /* Buffered data from another program.  */
 396           buffered = 1;
 397           gfi_ptr = &fn_buffer->info;
 398           length = GCOV_TAG_FUNCTION_LENGTH;
 399         }
 400       else
 401         {
 402           gfi_ptr = gi_ptr->functions[f_ix];
 403           if (gfi_ptr && gfi_ptr->key == gi_ptr)
 404             length = GCOV_TAG_FUNCTION_LENGTH;
 405           else
 406                 length = 0;
 407         }
 408
 409       gcov_write_tag_length (GCOV_TAG_FUNCTION, length);
 410       if (!length)
 411         continue;
 412
 413       gcov_write_unsigned (gfi_ptr->ident);
 414       gcov_write_unsigned (gfi_ptr->lineno_checksum);
 415       gcov_write_unsigned (gfi_ptr->cfg_checksum);
 416
 417       ci_ptr = gfi_ptr->ctrs;
 418       for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
 419         {
 420           gcov_position_t n_counts;
 421
 422           if (!gi_ptr->merge[t_ix])
 423             continue;
 424
 425           n_counts = ci_ptr->num;
 426
 427           if (gi_ptr->merge[t_ix] == __gcov_merge_topn)
 428             write_top_counters (ci_ptr, t_ix, n_counts);
 429           else
 430             {
 431               /* Do not stream when all counters are zero.  */
 432               int all_zeros = 1;
 433               for (unsigned i = 0; i < n_counts; i++)
 434                 if (ci_ptr->values[i] != 0)
 435                   {
 436                     all_zeros = 0;
 437                     break;
 438                   }
 439
 440               if (all_zeros)
 441                 gcov_write_tag_length (GCOV_TAG_FOR_COUNTER (t_ix),
 442                                        GCOV_TAG_COUNTER_LENGTH (-n_counts));
 443               else
 444                 {
 445                   gcov_write_tag_length (GCOV_TAG_FOR_COUNTER (t_ix),
 446                                          GCOV_TAG_COUNTER_LENGTH (n_counts));
 447                   for (unsigned i = 0; i < n_counts; i++)
 448                     gcov_write_counter (ci_ptr->values[i]);
 449                 }
 450             }
 451
 452           ci_ptr++;
 453         }
 454       if (buffered)
 455         fn_buffer = free_fn_data (gi_ptr, fn_buffer, GCOV_COUNTERS);
 456     }
 457
 458   gcov_write_unsigned (0);
 459 }
 460
 461 /* Dump the coverage counts for one gcov_info object. We merge with existing
 462    counts when possible, to avoid growing the .da files ad infinitum. We use
 463    this program's checksum to make sure we only accumulate whole program
 464    statistics to the correct summary. An object file might be embedded
 465    in two separate programs, and we must keep the two program
 466    summaries separate.  */
 467
 468 static void
 469 dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
 470                unsigned run_counted ATTRIBUTE_UNUSED,
 471                gcov_type run_max ATTRIBUTE_UNUSED)
 472 {
 473   struct gcov_summary summary = {};
 474   int error;
 475   gcov_unsigned_t tag;
 476   fn_buffer = 0;
 477
 478   error = gcov_exit_open_gcda_file (gi_ptr, gf);
 479   if (error == -1)
 480     return;
 481
 482   tag = gcov_read_unsigned ();
 483   if (tag)
 484     {
 485       /* Merge data from file.  */
 486       if (tag != GCOV_DATA_MAGIC)
 487         {
 488           gcov_error (GCOV_PROF_PREFIX "Not a gcov data file\n",
 489                       gf->filename);
 490           goto read_fatal;
 491         }
 492       error = merge_one_data (gf->filename, gi_ptr, &summary);
 493       if (error == -1)
 494         goto read_fatal;
 495     }
 496
 497   gcov_rewrite ();
 498
 499 #if !IN_GCOV_TOOL
 500   if (!run_counted)
 501     {
 502       summary.runs++;
 503       summary.sum_max += run_max;
 504     }
 505 #else
 506   summary = gi_ptr->summary;
 507 #endif
 508
 509   write_one_data (gi_ptr, &summary);
 510   /* fall through */
 511
 512 read_fatal:;
 513   while (fn_buffer)
 514     fn_buffer = free_fn_data (gi_ptr, fn_buffer, GCOV_COUNTERS);
 515
 516   if ((error = gcov_close ()))
 517     gcov_error (error  < 0 ?
 518                 GCOV_PROF_PREFIX "Overflow writing\n" :
 519                 GCOV_PROF_PREFIX "Error writing\n",
 520                 gf->filename);
 521 }
 522
 523
 524 /* Dump all the coverage counts for the program. It first computes program
 525    summary and then traverses gcov_list list and dumps the gcov_info
 526    objects one by one.  */
 527
 528 #if !IN_GCOV_TOOL
 529 static
 530 #endif
 531 void
 532 gcov_do_dump (struct gcov_info *list, int run_counted)
 533 {
 534   struct gcov_info *gi_ptr;
 535   struct gcov_filename gf;
 536
 537   /* Compute run_max of this program run.  */
 538   gcov_type run_max = 0;
 539   for (gi_ptr = list; gi_ptr; gi_ptr = gi_ptr->next)
 540     for (unsigned f_ix = 0; (unsigned)f_ix != gi_ptr->n_functions; f_ix++)
 541       {
 542         const struct gcov_ctr_info *cinfo
 543           = &gi_ptr->functions[f_ix]->ctrs[GCOV_COUNTER_ARCS];
 544
 545         for (unsigned i = 0; i < cinfo->num; i++)
 546           if (run_max < cinfo->values[i])
 547             run_max = cinfo->values[i];
 548       }
 549
 550   allocate_filename_struct (&gf);
 551
 552   /* Now merge each file.  */
 553   for (gi_ptr = list; gi_ptr; gi_ptr = gi_ptr->next)
 554     {
 555       dump_one_gcov (gi_ptr, &gf, run_counted, run_max);
 556       free (gf.filename);
 557     }
 558
 559   free (gf.prefix);
 560 }
 561
 562 #if IN_GCOV_TOOL
 563 const char *
 564 __attribute__ ((unused))
 565 gcov_get_filename (struct gcov_info *list)
 566 {
 567   return list->filename;
 568 }
 569 #endif
 570
 571 #if !IN_GCOV_TOOL
 572 void
 573 __gcov_dump_one (struct gcov_root *root)
 574 {
 575   if (root->dumped)
 576     return;
 577
 578   gcov_do_dump (root->list, root->run_counted);
 579
 580   root->dumped = 1;
 581   root->run_counted = 1;
 582 }
 583
 584 /* Per-dynamic-object gcov state.  */
 585 struct gcov_root __gcov_root;
 586
 587 /* Exactly one of these will be live in the process image.  */
 588 struct gcov_master __gcov_master =
 589   {GCOV_VERSION, 0};
 590
 591 void
 592 __gcov_exit (void)
 593 {
 594   __gcov_dump_one (&__gcov_root);
 595   if (__gcov_root.next)
 596     __gcov_root.next->prev = __gcov_root.prev;
 597   if (__gcov_root.prev)
 598     __gcov_root.prev->next = __gcov_root.next;
 599   else
 600     __gcov_master.root = __gcov_root.next;
 601
 602   gcov_error_exit ();
 603 }
 604
 605 /* Add a new object file onto the bb chain.  Invoked automatically
 606   when running an object file's global ctors.  */
 607
 608 void
 609 __gcov_init (struct gcov_info *info)
 610 {
 611   if (!info->version || !info->n_functions)
 612     return;
 613   if (gcov_version (info, info->version, 0))
 614     {
 615       if (!__gcov_root.list)
 616         {
 617           /* Add to master list and at exit function.  */
 618           if (gcov_version (NULL, __gcov_master.version, "<master>"))
 619             {
 620               __gcov_root.next = __gcov_master.root;
 621               if (__gcov_master.root)
 622                 __gcov_master.root->prev = &__gcov_root;
 623               __gcov_master.root = &__gcov_root;
 624             }
 625         }
 626
 627       info->next = __gcov_root.list;
 628       __gcov_root.list = info;
 629     }
 630 }
 631 #endif /* !IN_GCOV_TOOL */
 632 #endif /* L_gcov */
 633 #endif /* inhibit_libc */