bfd/stabs.c

   1 /* Stabs in sections linking support.
   2    Copyright (C) 1996-2020 Free Software Foundation, Inc.
   3    Written by Ian Lance Taylor, Cygnus Support.
   4
   5    This file is part of BFD, the Binary File Descriptor library.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  20    MA 02110-1301, USA.  */
  21
  22
  23 /* This file contains support for linking stabs in sections, as used
  24    on COFF and ELF.  */
  25
  26 #include "sysdep.h"
  27 #include "bfd.h"
  28 #include "libbfd.h"
  29 #include "aout/stab_gnu.h"
  30 #include "safe-ctype.h"
  31
  32 /* Stabs entries use a 12 byte format:
  33      4 byte string table index
  34      1 byte stab type
  35      1 byte stab other field
  36      2 byte stab desc field
  37      4 byte stab value
  38    FIXME: This will have to change for a 64 bit object format.
  39
  40    The stabs symbols are divided into compilation units.  For the
  41    first entry in each unit, the type of 0, the value is the length of
  42    the string table for this unit, and the desc field is the number of
  43    stabs symbols for this unit.  */
  44
  45 #define STRDXOFF  0
  46 #define TYPEOFF   4
  47 #define OTHEROFF  5
  48 #define DESCOFF   6
  49 #define VALOFF    8
  50 #define STABSIZE  12
  51
  52 /* A linked list of totals that we have found for a particular header
  53    file.  A total is a unique identifier for a particular BINCL...EINCL
  54    sequence of STABs that can be used to identify duplicate sequences.
  55    It consists of three fields, 'sum_chars' which is the sum of all the
  56    STABS characters; 'num_chars' which is the number of these charactes
  57    and 'symb' which is a buffer of all the symbols in the sequence.  This
  58    buffer is only checked as a last resort.  */
  59
  60 struct stab_link_includes_totals
  61 {
  62   struct stab_link_includes_totals *next;
  63   bfd_vma sum_chars;  /* Accumulated sum of STABS characters.  */
  64   bfd_vma num_chars;  /* Number of STABS characters.  */
  65   const char* symb;   /* The STABS characters themselves.  */
  66 };
  67
  68 /* An entry in the header file hash table.  */
  69
  70 struct stab_link_includes_entry
  71 {
  72   struct bfd_hash_entry root;
  73   /* List of totals we have found for this file.  */
  74   struct stab_link_includes_totals *totals;
  75 };
  76
  77 /* This structure is used to hold a list of N_BINCL symbols, some of
  78    which might be converted into N_EXCL symbols.  */
  79
  80 struct stab_excl_list
  81 {
  82   /* The next symbol to convert.  */
  83   struct stab_excl_list *next;
  84   /* The offset to this symbol in the section contents.  */
  85   bfd_size_type offset;
  86   /* The value to use for the symbol.  */
  87   bfd_vma val;
  88   /* The type of this symbol (N_BINCL or N_EXCL).  */
  89   int type;
  90 };
  91
  92 /* This structure is stored with each .stab section.  */
  93
  94 struct stab_section_info
  95 {
  96   /* This is a linked list of N_BINCL symbols which should be
  97      converted into N_EXCL symbols.  */
  98   struct stab_excl_list *excls;
  99
 100   /* This is used to map input stab offsets within their sections
 101      to output stab offsets, to take into account stabs that have
 102      been deleted.  If it is NULL, the output offsets are the same
 103      as the input offsets, because no stabs have been deleted from
 104      this section.  Otherwise the i'th entry is the number of
 105      bytes of stabs that have been deleted prior to the i'th
 106      stab.  */
 107   bfd_size_type *cumulative_skips;
 108
 109   /* This is an array of string indices.  For each stab symbol, we
 110      store the string index here.  If a stab symbol should not be
 111      included in the final output, the string index is -1.  */
 112   bfd_size_type stridxs[1];
 113 };
 114
 115 \f
 116 /* The function to create a new entry in the header file hash table.  */
 117
 118 static struct bfd_hash_entry *
 119 stab_link_includes_newfunc (struct bfd_hash_entry *entry,
 120                             struct bfd_hash_table *table,
 121                             const char *string)
 122 {
 123   struct stab_link_includes_entry *ret =
 124     (struct stab_link_includes_entry *) entry;
 125
 126   /* Allocate the structure if it has not already been allocated by a
 127      subclass.  */
 128   if (ret == NULL)
 129     ret = (struct stab_link_includes_entry *)
 130         bfd_hash_allocate (table, sizeof (struct stab_link_includes_entry));
 131   if (ret == NULL)
 132     return NULL;
 133
 134   /* Call the allocation method of the superclass.  */
 135   ret = ((struct stab_link_includes_entry *)
 136          bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
 137   if (ret)
 138     /* Set local fields.  */
 139     ret->totals = NULL;
 140
 141   return (struct bfd_hash_entry *) ret;
 142 }
 143 \f
 144 /* This function is called for each input file from the add_symbols
 145    pass of the linker.  */
 146
 147 bfd_boolean
 148 _bfd_link_section_stabs (bfd *abfd,
 149                          struct stab_info *sinfo,
 150                          asection *stabsec,
 151                          asection *stabstrsec,
 152                          void * *psecinfo,
 153                          bfd_size_type *pstring_offset)
 154 {
 155   bfd_boolean first;
 156   bfd_size_type count, amt;
 157   struct stab_section_info *secinfo;
 158   bfd_byte *stabbuf = NULL;
 159   bfd_byte *stabstrbuf = NULL;
 160   bfd_byte *sym, *symend;
 161   bfd_size_type stroff, next_stroff, skip;
 162   bfd_size_type *pstridx;
 163
 164   if (stabsec->size == 0
 165       || stabstrsec->size == 0)
 166     /* This file does not contain stabs debugging information.  */
 167     return TRUE;
 168
 169   if (stabsec->size % STABSIZE != 0)
 170     /* Something is wrong with the format of these stab symbols.
 171        Don't try to optimize them.  */
 172     return TRUE;
 173
 174   if ((stabstrsec->flags & SEC_RELOC) != 0)
 175     /* We shouldn't see relocations in the strings, and we aren't
 176        prepared to handle them.  */
 177     return TRUE;
 178
 179   if (bfd_is_abs_section (stabsec->output_section)
 180       || bfd_is_abs_section (stabstrsec->output_section))
 181     /* At least one of the sections is being discarded from the
 182        link, so we should just ignore them.  */
 183     return TRUE;
 184
 185   first = FALSE;
 186
 187   if (sinfo->stabstr == NULL)
 188     {
 189       flagword flags;
 190
 191       /* Initialize the stabs information we need to keep track of.  */
 192       first = TRUE;
 193       sinfo->strings = _bfd_stringtab_init ();
 194       if (sinfo->strings == NULL)
 195         goto error_return;
 196       /* Make sure the first byte is zero.  */
 197       (void) _bfd_stringtab_add (sinfo->strings, "", TRUE, TRUE);
 198       if (! bfd_hash_table_init (&sinfo->includes,
 199                                  stab_link_includes_newfunc,
 200                                  sizeof (struct stab_link_includes_entry)))
 201         goto error_return;
 202       flags = (SEC_HAS_CONTENTS | SEC_READONLY | SEC_DEBUGGING
 203                | SEC_LINKER_CREATED);
 204       sinfo->stabstr = bfd_make_section_anyway_with_flags (abfd, ".stabstr",
 205                                                            flags);
 206       if (sinfo->stabstr == NULL)
 207         goto error_return;
 208     }
 209
 210   /* Initialize the information we are going to store for this .stab
 211      section.  */
 212   count = stabsec->size / STABSIZE;
 213
 214   amt = sizeof (struct stab_section_info);
 215   amt += (count - 1) * sizeof (bfd_size_type);
 216   *psecinfo = bfd_alloc (abfd, amt);
 217   if (*psecinfo == NULL)
 218     goto error_return;
 219
 220   secinfo = (struct stab_section_info *) *psecinfo;
 221   secinfo->excls = NULL;
 222   stabsec->rawsize = stabsec->size;
 223   secinfo->cumulative_skips = NULL;
 224   memset (secinfo->stridxs, 0, (size_t) count * sizeof (bfd_size_type));
 225
 226   /* Read the stabs information from abfd.  */
 227   if (!bfd_malloc_and_get_section (abfd, stabsec, &stabbuf)
 228       || !bfd_malloc_and_get_section (abfd, stabstrsec, &stabstrbuf))
 229     goto error_return;
 230
 231   /* Look through the stabs symbols, work out the new string indices,
 232      and identify N_BINCL symbols which can be eliminated.  */
 233   stroff = 0;
 234   /* The stabs sections can be split when
 235      -split-by-reloc/-split-by-file is used.  We must keep track of
 236      each stab section's place in the single concatenated string
 237      table.  */
 238   next_stroff = pstring_offset ? *pstring_offset : 0;
 239   skip = 0;
 240
 241   symend = stabbuf + stabsec->size;
 242   for (sym = stabbuf, pstridx = secinfo->stridxs;
 243        sym < symend;
 244        sym += STABSIZE, ++pstridx)
 245     {
 246       bfd_size_type symstroff;
 247       int type;
 248       const char *string;
 249
 250       if (*pstridx != 0)
 251         /* This symbol has already been handled by an N_BINCL pass.  */
 252         continue;
 253
 254       type = sym[TYPEOFF];
 255
 256       if (type == 0)
 257         {
 258           /* Special type 0 stabs indicate the offset to the next
 259              string table.  We only copy the very first one.  */
 260           stroff = next_stroff;
 261           next_stroff += bfd_get_32 (abfd, sym + 8);
 262           if (pstring_offset)
 263             *pstring_offset = next_stroff;
 264           if (! first)
 265             {
 266               *pstridx = (bfd_size_type) -1;
 267               ++skip;
 268               continue;
 269             }
 270           first = FALSE;
 271         }
 272
 273       /* Store the string in the hash table, and record the index.  */
 274       symstroff = stroff + bfd_get_32 (abfd, sym + STRDXOFF);
 275       if (symstroff >= stabstrsec->size)
 276         {
 277           _bfd_error_handler
 278             /* xgettext:c-format */
 279             (_("%pB(%pA+%#lx): stabs entry has invalid string index"),
 280              abfd, stabsec, (long) (sym - stabbuf));
 281           bfd_set_error (bfd_error_bad_value);
 282           goto error_return;
 283         }
 284       string = (char *) stabstrbuf + symstroff;
 285       *pstridx = _bfd_stringtab_add (sinfo->strings, string, TRUE, TRUE);
 286
 287       /* An N_BINCL symbol indicates the start of the stabs entries
 288          for a header file.  We need to scan ahead to the next N_EINCL
 289          symbol, ignoring nesting, adding up all the characters in the
 290          symbol names, not including the file numbers in types (the
 291          first number after an open parenthesis).  */
 292       if (type == (int) N_BINCL)
 293         {
 294           bfd_vma sum_chars;
 295           bfd_vma num_chars;
 296           bfd_vma buf_len = 0;
 297           char * symb;
 298           char * symb_rover;
 299           int nest;
 300           bfd_byte * incl_sym;
 301           struct stab_link_includes_entry * incl_entry;
 302           struct stab_link_includes_totals * t;
 303           struct stab_excl_list * ne;
 304
 305           symb = symb_rover = NULL;
 306           sum_chars = num_chars = 0;
 307           nest = 0;
 308
 309           for (incl_sym = sym + STABSIZE;
 310                incl_sym < symend;
 311                incl_sym += STABSIZE)
 312             {
 313               int incl_type;
 314
 315               incl_type = incl_sym[TYPEOFF];
 316               if (incl_type == 0)
 317                 break;
 318               else if (incl_type == (int) N_EXCL)
 319                 continue;
 320               else if (incl_type == (int) N_EINCL)
 321                 {
 322                   if (nest == 0)
 323                     break;
 324                   --nest;
 325                 }
 326               else if (incl_type == (int) N_BINCL)
 327                 ++nest;
 328               else if (nest == 0)
 329                 {
 330                   const char *str;
 331
 332                   str = ((char *) stabstrbuf
 333                          + stroff
 334                          + bfd_get_32 (abfd, incl_sym + STRDXOFF));
 335                   for (; *str != '\0'; str++)
 336                     {
 337                       if (num_chars >= buf_len)
 338                         {
 339                           buf_len += 32 * 1024;
 340                           symb = (char *) bfd_realloc_or_free (symb, buf_len);
 341                           if (symb == NULL)
 342                             goto error_return;
 343                           symb_rover = symb + num_chars;
 344                         }
 345                       * symb_rover ++ = * str;
 346                       sum_chars += *str;
 347                       num_chars ++;
 348                       if (*str == '(')
 349                         {
 350                           /* Skip the file number.  */
 351                           ++str;
 352                           while (ISDIGIT (*str))
 353                             ++str;
 354                           --str;
 355                         }
 356                     }
 357                 }
 358             }
 359
 360           BFD_ASSERT (num_chars == (bfd_vma) (symb_rover - symb));
 361
 362           /* If we have already included a header file with the same
 363              value, then replaced this one with an N_EXCL symbol.  */
 364           incl_entry = (struct stab_link_includes_entry * )
 365             bfd_hash_lookup (&sinfo->includes, string, TRUE, TRUE);
 366           if (incl_entry == NULL)
 367             goto error_return;
 368
 369           for (t = incl_entry->totals; t != NULL; t = t->next)
 370             if (t->sum_chars == sum_chars
 371                 && t->num_chars == num_chars
 372                 && memcmp (t->symb, symb, num_chars) == 0)
 373               break;
 374
 375           /* Record this symbol, so that we can set the value
 376              correctly.  */
 377           amt = sizeof *ne;
 378           ne = (struct stab_excl_list *) bfd_alloc (abfd, amt);
 379           if (ne == NULL)
 380             goto error_return;
 381           ne->offset = sym - stabbuf;
 382           ne->val = sum_chars;
 383           ne->type = (int) N_BINCL;
 384           ne->next = secinfo->excls;
 385           secinfo->excls = ne;
 386
 387           if (t == NULL)
 388             {
 389               /* This is the first time we have seen this header file
 390                  with this set of stabs strings.  */
 391               t = (struct stab_link_includes_totals *)
 392                   bfd_hash_allocate (&sinfo->includes, sizeof *t);
 393               if (t == NULL)
 394                 goto error_return;
 395               t->sum_chars = sum_chars;
 396               t->num_chars = num_chars;
 397               /* Trim data down.  */
 398               t->symb = symb = (char *) bfd_realloc_or_free (symb, num_chars);
 399               t->next = incl_entry->totals;
 400               incl_entry->totals = t;
 401             }
 402           else
 403             {
 404               bfd_size_type *incl_pstridx;
 405
 406               /* We have seen this header file before.  Tell the final
 407                  pass to change the type to N_EXCL.  */
 408               ne->type = (int) N_EXCL;
 409
 410               /* Free off superfluous symbols.  */
 411               free (symb);
 412
 413               /* Mark the skipped symbols.  */
 414
 415               nest = 0;
 416               for (incl_sym = sym + STABSIZE, incl_pstridx = pstridx + 1;
 417                    incl_sym < symend;
 418                    incl_sym += STABSIZE, ++incl_pstridx)
 419                 {
 420                   int incl_type;
 421
 422                   incl_type = incl_sym[TYPEOFF];
 423
 424                   if (incl_type == (int) N_EINCL)
 425                     {
 426                       if (nest == 0)
 427                         {
 428                           *incl_pstridx = (bfd_size_type) -1;
 429                           ++skip;
 430                           break;
 431                         }
 432                       --nest;
 433                     }
 434                   else if (incl_type == (int) N_BINCL)
 435                     ++nest;
 436                   else if (incl_type == (int) N_EXCL)
 437                     /* Keep existing exclusion marks.  */
 438                     continue;
 439                   else if (nest == 0)
 440                     {
 441                       *incl_pstridx = (bfd_size_type) -1;
 442                       ++skip;
 443                     }
 444                 }
 445             }
 446         }
 447     }
 448
 449   free (stabbuf);
 450   stabbuf = NULL;
 451   free (stabstrbuf);
 452   stabstrbuf = NULL;
 453
 454   /* We need to set the section sizes such that the linker will
 455      compute the output section sizes correctly.  We set the .stab
 456      size to not include the entries we don't want.  We set
 457      SEC_EXCLUDE for the .stabstr section, so that it will be dropped
 458      from the link.  We record the size of the strtab in the first
 459      .stabstr section we saw, and make sure we don't set SEC_EXCLUDE
 460      for that section.  */
 461   stabsec->size = (count - skip) * STABSIZE;
 462   if (stabsec->size == 0)
 463     stabsec->flags |= SEC_EXCLUDE | SEC_KEEP;
 464   stabstrsec->flags |= SEC_EXCLUDE | SEC_KEEP;
 465   sinfo->stabstr->size = _bfd_stringtab_size (sinfo->strings);
 466
 467   /* Calculate the `cumulative_skips' array now that stabs have been
 468      deleted for this section.  */
 469
 470   if (skip != 0)
 471     {
 472       bfd_size_type i, offset;
 473       bfd_size_type *pskips;
 474
 475       amt = count * sizeof (bfd_size_type);
 476       secinfo->cumulative_skips = (bfd_size_type *) bfd_alloc (abfd, amt);
 477       if (secinfo->cumulative_skips == NULL)
 478         goto error_return;
 479
 480       pskips = secinfo->cumulative_skips;
 481       pstridx = secinfo->stridxs;
 482       offset = 0;
 483
 484       for (i = 0; i < count; i++, pskips++, pstridx++)
 485         {
 486           *pskips = offset;
 487           if (*pstridx == (bfd_size_type) -1)
 488             offset += STABSIZE;
 489         }
 490
 491       BFD_ASSERT (offset != 0);
 492     }
 493
 494   return TRUE;
 495
 496  error_return:
 497   free (stabbuf);
 498   free (stabstrbuf);
 499   return FALSE;
 500 }
 501 \f
 502 /* This function is called for each input file before the stab
 503    section is relocated.  It discards stab entries for discarded
 504    functions and variables.  The function returns TRUE iff
 505    any entries have been deleted.
 506 */
 507
 508 bfd_boolean
 509 _bfd_discard_section_stabs (bfd *abfd,
 510                             asection *stabsec,
 511                             void * psecinfo,
 512                             bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *),
 513                             void * cookie)
 514 {
 515   bfd_size_type count, amt;
 516   struct stab_section_info *secinfo;
 517   bfd_byte *stabbuf = NULL;
 518   bfd_byte *sym, *symend;
 519   bfd_size_type skip;
 520   bfd_size_type *pstridx;
 521   int deleting;
 522
 523   if (stabsec->size == 0)
 524     /* This file does not contain stabs debugging information.  */
 525     return FALSE;
 526
 527   if (stabsec->size % STABSIZE != 0)
 528     /* Something is wrong with the format of these stab symbols.
 529        Don't try to optimize them.  */
 530     return FALSE;
 531
 532   if ((stabsec->output_section != NULL
 533        && bfd_is_abs_section (stabsec->output_section)))
 534     /* At least one of the sections is being discarded from the
 535        link, so we should just ignore them.  */
 536     return FALSE;
 537
 538   /* We should have initialized our data in _bfd_link_section_stabs.
 539      If there was some bizarre error reading the string sections, though,
 540      we might not have.  Bail rather than asserting.  */
 541   if (psecinfo == NULL)
 542     return FALSE;
 543
 544   count = stabsec->rawsize / STABSIZE;
 545   secinfo = (struct stab_section_info *) psecinfo;
 546
 547   /* Read the stabs information from abfd.  */
 548   if (!bfd_malloc_and_get_section (abfd, stabsec, &stabbuf))
 549     goto error_return;
 550
 551   /* Look through the stabs symbols and discard any information for
 552      discarded functions.  */
 553   skip = 0;
 554   deleting = -1;
 555
 556   symend = stabbuf + stabsec->rawsize;
 557   for (sym = stabbuf, pstridx = secinfo->stridxs;
 558        sym < symend;
 559        sym += STABSIZE, ++pstridx)
 560     {
 561       int type;
 562
 563       if (*pstridx == (bfd_size_type) -1)
 564         /* This stab was deleted in a previous pass.  */
 565         continue;
 566
 567       type = sym[TYPEOFF];
 568
 569       if (type == (int) N_FUN)
 570         {
 571           int strx = bfd_get_32 (abfd, sym + STRDXOFF);
 572
 573           if (strx == 0)
 574             {
 575               if (deleting)
 576                 {
 577                   skip++;
 578                   *pstridx = -1;
 579                 }
 580               deleting = -1;
 581               continue;
 582             }
 583           deleting = 0;
 584           if ((*reloc_symbol_deleted_p) (sym + VALOFF - stabbuf, cookie))
 585             deleting = 1;
 586         }
 587
 588       if (deleting == 1)
 589         {
 590           *pstridx = -1;
 591           skip++;
 592         }
 593       else if (deleting == -1)
 594         {
 595           /* Outside of a function.  Check for deleted variables.  */
 596           if (type == (int) N_STSYM || type == (int) N_LCSYM)
 597             if ((*reloc_symbol_deleted_p) (sym + VALOFF - stabbuf, cookie))
 598               {
 599                 *pstridx = -1;
 600                 skip ++;
 601               }
 602           /* We should also check for N_GSYM entries which reference a
 603              deleted global, but those are less harmful to debuggers
 604              and would require parsing the stab strings.  */
 605         }
 606     }
 607
 608   free (stabbuf);
 609   stabbuf = NULL;
 610
 611   /* Shrink the stabsec as needed.  */
 612   stabsec->size -= skip * STABSIZE;
 613   if (stabsec->size == 0)
 614     stabsec->flags |= SEC_EXCLUDE | SEC_KEEP;
 615
 616   /* Recalculate the `cumulative_skips' array now that stabs have been
 617      deleted for this section.  */
 618
 619   if (skip != 0)
 620     {
 621       bfd_size_type i, offset;
 622       bfd_size_type *pskips;
 623
 624       if (secinfo->cumulative_skips == NULL)
 625         {
 626           amt = count * sizeof (bfd_size_type);
 627           secinfo->cumulative_skips = (bfd_size_type *) bfd_alloc (abfd, amt);
 628           if (secinfo->cumulative_skips == NULL)
 629             goto error_return;
 630         }
 631
 632       pskips = secinfo->cumulative_skips;
 633       pstridx = secinfo->stridxs;
 634       offset = 0;
 635
 636       for (i = 0; i < count; i++, pskips++, pstridx++)
 637         {
 638           *pskips = offset;
 639           if (*pstridx == (bfd_size_type) -1)
 640             offset += STABSIZE;
 641         }
 642
 643       BFD_ASSERT (offset != 0);
 644     }
 645
 646   return skip > 0;
 647
 648  error_return:
 649   free (stabbuf);
 650   return FALSE;
 651 }
 652
 653 /* Write out the stab section.  This is called with the relocated
 654    contents.  */
 655
 656 bfd_boolean
 657 _bfd_write_section_stabs (bfd *output_bfd,
 658                           struct stab_info *sinfo,
 659                           asection *stabsec,
 660                           void * *psecinfo,
 661                           bfd_byte *contents)
 662 {
 663   struct stab_section_info *secinfo;
 664   struct stab_excl_list *e;
 665   bfd_byte *sym, *tosym, *symend;
 666   bfd_size_type *pstridx;
 667
 668   secinfo = (struct stab_section_info *) *psecinfo;
 669
 670   if (secinfo == NULL)
 671     return bfd_set_section_contents (output_bfd, stabsec->output_section,
 672                                      contents, stabsec->output_offset,
 673                                      stabsec->size);
 674
 675   /* Handle each N_BINCL entry.  */
 676   for (e = secinfo->excls; e != NULL; e = e->next)
 677     {
 678       bfd_byte *excl_sym;
 679
 680       BFD_ASSERT (e->offset < stabsec->rawsize);
 681       excl_sym = contents + e->offset;
 682       bfd_put_32 (output_bfd, e->val, excl_sym + VALOFF);
 683       excl_sym[TYPEOFF] = e->type;
 684     }
 685
 686   /* Copy over all the stabs symbols, omitting the ones we don't want,
 687      and correcting the string indices for those we do want.  */
 688   tosym = contents;
 689   symend = contents + stabsec->rawsize;
 690   for (sym = contents, pstridx = secinfo->stridxs;
 691        sym < symend;
 692        sym += STABSIZE, ++pstridx)
 693     {
 694       if (*pstridx != (bfd_size_type) -1)
 695         {
 696           if (tosym != sym)
 697             memcpy (tosym, sym, STABSIZE);
 698           bfd_put_32 (output_bfd, *pstridx, tosym + STRDXOFF);
 699
 700           if (sym[TYPEOFF] == 0)
 701             {
 702               /* This is the header symbol for the stabs section.  We
 703                  don't really need one, since we have merged all the
 704                  input stabs sections into one, but we generate one
 705                  for the benefit of readers which expect to see one.  */
 706               BFD_ASSERT (sym == contents);
 707               bfd_put_32 (output_bfd, _bfd_stringtab_size (sinfo->strings),
 708                           tosym + VALOFF);
 709               bfd_put_16 (output_bfd,
 710                           stabsec->output_section->size / STABSIZE - 1,
 711                           tosym + DESCOFF);
 712             }
 713
 714           tosym += STABSIZE;
 715         }
 716     }
 717
 718   BFD_ASSERT ((bfd_size_type) (tosym - contents) == stabsec->size);
 719
 720   return bfd_set_section_contents (output_bfd, stabsec->output_section,
 721                                    contents, (file_ptr) stabsec->output_offset,
 722                                    stabsec->size);
 723 }
 724
 725 /* Write out the .stabstr section.  */
 726
 727 bfd_boolean
 728 _bfd_write_stab_strings (bfd *output_bfd, struct stab_info *sinfo)
 729 {
 730   if (bfd_is_abs_section (sinfo->stabstr->output_section))
 731     /* The section was discarded from the link.  */
 732     return TRUE;
 733
 734   BFD_ASSERT ((sinfo->stabstr->output_offset
 735                + _bfd_stringtab_size (sinfo->strings))
 736               <= sinfo->stabstr->output_section->size);
 737
 738   if (bfd_seek (output_bfd,
 739                 (file_ptr) (sinfo->stabstr->output_section->filepos
 740                             + sinfo->stabstr->output_offset),
 741                 SEEK_SET) != 0)
 742     return FALSE;
 743
 744   if (! _bfd_stringtab_emit (output_bfd, sinfo->strings))
 745     return FALSE;
 746
 747   /* We no longer need the stabs information.  */
 748   _bfd_stringtab_free (sinfo->strings);
 749   bfd_hash_table_free (&sinfo->includes);
 750
 751   return TRUE;
 752 }
 753
 754 /* Adjust an address in the .stab section.  Given OFFSET within
 755    STABSEC, this returns the new offset in the adjusted stab section,
 756    or -1 if the address refers to a stab which has been removed.  */
 757
 758 bfd_vma
 759 _bfd_stab_section_offset (asection *stabsec,
 760                           void * psecinfo,
 761                           bfd_vma offset)
 762 {
 763   struct stab_section_info *secinfo;
 764
 765   secinfo = (struct stab_section_info *) psecinfo;
 766
 767   if (secinfo == NULL)
 768     return offset;
 769
 770   if (offset >= stabsec->rawsize)
 771     return offset - stabsec->rawsize + stabsec->size;
 772
 773   if (secinfo->cumulative_skips)
 774     {
 775       bfd_vma i;
 776
 777       i = offset / STABSIZE;
 778
 779       if (secinfo->stridxs [i] == (bfd_size_type) -1)
 780         return (bfd_vma) -1;
 781
 782       return offset - secinfo->cumulative_skips [i];
 783     }
 784
 785   return offset;
 786 }