bfd/merge.c

   1 /* SEC_MERGE support.
   2    Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    Written by Jakub Jelinek <jakub@redhat.com>.
   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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /* This file contains support for merging duplicate entities within sections,
  22    as used in ELF SHF_MERGE.  */
  23
  24 #include "bfd.h"
  25 #include "sysdep.h"
  26 #include "libbfd.h"
  27 #include "hashtab.h"
  28 #include "libiberty.h"
  29
  30 struct sec_merge_sec_info;
  31
  32 /* An entry in the section merge hash table.  */
  33
  34 struct sec_merge_hash_entry
  35 {
  36   struct bfd_hash_entry root;
  37   /* Length of this entry.  This includes the zero terminator.  */
  38   unsigned int len;
  39   /* Start of this string needs to be aligned to
  40      alignment octets (not 1 << align).  */
  41   unsigned int alignment;
  42   union
  43   {
  44     /* Index within the merged section.  */
  45     bfd_size_type index;
  46     /* Entry this is a suffix of (if alignment is 0).  */
  47     struct sec_merge_hash_entry *suffix;
  48   } u;
  49   /* Which section is it in.  */
  50   struct sec_merge_sec_info *secinfo;
  51   /* Next entity in the hash table.  */
  52   struct sec_merge_hash_entry *next;
  53 };
  54
  55 /* The section merge hash table.  */
  56
  57 struct sec_merge_hash
  58 {
  59   struct bfd_hash_table table;
  60   /* Next available index.  */
  61   bfd_size_type size;
  62   /* First entity in the SEC_MERGE sections of this type.  */
  63   struct sec_merge_hash_entry *first;
  64   /* Last entity in the SEC_MERGE sections of this type.  */
  65   struct sec_merge_hash_entry *last;
  66   /* Entity size.  */
  67   unsigned int entsize;
  68   /* Are entries fixed size or zero terminated strings?  */
  69   bfd_boolean strings;
  70 };
  71
  72 struct sec_merge_info
  73 {
  74   /* Chain of sec_merge_infos.  */
  75   struct sec_merge_info *next;
  76   /* Chain of sec_merge_sec_infos.  */
  77   struct sec_merge_sec_info *chain;
  78   /* A hash table used to hold section content.  */
  79   struct sec_merge_hash *htab;
  80 };
  81
  82 struct sec_merge_sec_info
  83 {
  84   /* Chain of sec_merge_sec_infos.  */
  85   struct sec_merge_sec_info *next;
  86   /* The corresponding section.  */
  87   asection *sec;
  88   /* Pointer to merge_info pointing to us.  */
  89   void **psecinfo;
  90   /* A hash table used to hold section content.  */
  91   struct sec_merge_hash *htab;
  92   /* First string in this section.  */
  93   struct sec_merge_hash_entry *first_str;
  94   /* Original section content.  */
  95   unsigned char contents[1];
  96 };
  97
  98
  99 /* Routine to create an entry in a section merge hashtab.  */
 100
 101 static struct bfd_hash_entry *
 102 sec_merge_hash_newfunc (struct bfd_hash_entry *entry,
 103                         struct bfd_hash_table *table, const char *string)
 104 {
 105   /* Allocate the structure if it has not already been allocated by a
 106      subclass.  */
 107   if (entry == NULL)
 108     entry = bfd_hash_allocate (table, sizeof (struct sec_merge_hash_entry));
 109   if (entry == NULL)
 110     return NULL;
 111
 112   /* Call the allocation method of the superclass.  */
 113   entry = bfd_hash_newfunc (entry, table, string);
 114
 115   if (entry != NULL)
 116     {
 117       /* Initialize the local fields.  */
 118       struct sec_merge_hash_entry *ret = (struct sec_merge_hash_entry *) entry;
 119
 120       ret->u.suffix = NULL;
 121       ret->alignment = 0;
 122       ret->secinfo = NULL;
 123       ret->next = NULL;
 124     }
 125
 126   return entry;
 127 }
 128
 129 /* Look up an entry in a section merge hash table.  */
 130
 131 static struct sec_merge_hash_entry *
 132 sec_merge_hash_lookup (struct sec_merge_hash *table, const char *string,
 133                        unsigned int alignment, bfd_boolean create)
 134 {
 135   register const unsigned char *s;
 136   register unsigned long hash;
 137   register unsigned int c;
 138   struct sec_merge_hash_entry *hashp;
 139   unsigned int len, i;
 140   unsigned int index;
 141
 142   hash = 0;
 143   len = 0;
 144   s = (const unsigned char *) string;
 145   if (table->strings)
 146     {
 147       if (table->entsize == 1)
 148         {
 149           while ((c = *s++) != '\0')
 150             {
 151               hash += c + (c << 17);
 152               hash ^= hash >> 2;
 153               ++len;
 154             }
 155           hash += len + (len << 17);
 156         }
 157       else
 158         {
 159           for (;;)
 160             {
 161               for (i = 0; i < table->entsize; ++i)
 162                 if (s[i] != '\0')
 163                   break;
 164               if (i == table->entsize)
 165                 break;
 166               for (i = 0; i < table->entsize; ++i)
 167                 {
 168                   c = *s++;
 169                   hash += c + (c << 17);
 170                   hash ^= hash >> 2;
 171                 }
 172               ++len;
 173             }
 174           hash += len + (len << 17);
 175           len *= table->entsize;
 176         }
 177       hash ^= hash >> 2;
 178       len += table->entsize;
 179     }
 180   else
 181     {
 182       for (i = 0; i < table->entsize; ++i)
 183         {
 184           c = *s++;
 185           hash += c + (c << 17);
 186           hash ^= hash >> 2;
 187         }
 188       len = table->entsize;
 189     }
 190
 191   index = hash % table->table.size;
 192   for (hashp = (struct sec_merge_hash_entry *) table->table.table[index];
 193        hashp != NULL;
 194        hashp = (struct sec_merge_hash_entry *) hashp->root.next)
 195     {
 196       if (hashp->root.hash == hash
 197           && len == hashp->len
 198           && memcmp (hashp->root.string, string, len) == 0)
 199         {
 200           /* If the string we found does not have at least the required
 201              alignment, we need to insert another copy.  */
 202           if (hashp->alignment < alignment)
 203             {
 204               if (create)
 205                 {
 206                   /*  Mark the less aligned copy as deleted.  */
 207                   hashp->len = 0;
 208                   hashp->alignment = 0;
 209                 }
 210               break;
 211             }
 212           return hashp;
 213         }
 214     }
 215
 216   if (! create)
 217     return NULL;
 218
 219   hashp = ((struct sec_merge_hash_entry *)
 220            sec_merge_hash_newfunc (NULL, &table->table, string));
 221   if (hashp == NULL)
 222     return NULL;
 223   hashp->root.string = string;
 224   hashp->root.hash = hash;
 225   hashp->len = len;
 226   hashp->alignment = alignment;
 227   hashp->root.next = table->table.table[index];
 228   table->table.table[index] = (struct bfd_hash_entry *) hashp;
 229
 230   return hashp;
 231 }
 232
 233 /* Create a new hash table.  */
 234
 235 static struct sec_merge_hash *
 236 sec_merge_init (unsigned int entsize, bfd_boolean strings)
 237 {
 238   struct sec_merge_hash *table;
 239
 240   table = bfd_malloc (sizeof (struct sec_merge_hash));
 241   if (table == NULL)
 242     return NULL;
 243
 244   if (! bfd_hash_table_init (&table->table, sec_merge_hash_newfunc))
 245     {
 246       free (table);
 247       return NULL;
 248     }
 249
 250   table->size = 0;
 251   table->first = NULL;
 252   table->last = NULL;
 253   table->entsize = entsize;
 254   table->strings = strings;
 255
 256   return table;
 257 }
 258
 259 /* Get the index of an entity in a hash table, adding it if it is not
 260    already present.  */
 261
 262 static struct sec_merge_hash_entry *
 263 sec_merge_add (struct sec_merge_hash *tab, const char *str,
 264                unsigned int alignment, struct sec_merge_sec_info *secinfo)
 265 {
 266   register struct sec_merge_hash_entry *entry;
 267
 268   entry = sec_merge_hash_lookup (tab, str, alignment, TRUE);
 269   if (entry == NULL)
 270     return NULL;
 271
 272   if (entry->secinfo == NULL)
 273     {
 274       tab->size++;
 275       entry->secinfo = secinfo;
 276       if (tab->first == NULL)
 277         tab->first = entry;
 278       else
 279         tab->last->next = entry;
 280       tab->last = entry;
 281     }
 282
 283   return entry;
 284 }
 285
 286 static bfd_boolean
 287 sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
 288 {
 289   struct sec_merge_sec_info *secinfo = entry->secinfo;
 290   asection *sec = secinfo->sec;
 291   char *pad = NULL;
 292   bfd_size_type off = 0;
 293   int alignment_power = sec->output_section->alignment_power;
 294
 295   if (alignment_power)
 296     {
 297       pad = bfd_zmalloc ((bfd_size_type) 1 << alignment_power);
 298       if (pad == NULL)
 299         return FALSE;
 300     }
 301
 302   for (; entry != NULL && entry->secinfo == secinfo; entry = entry->next)
 303     {
 304       const char *str;
 305       bfd_size_type len;
 306
 307       len = -off & (entry->alignment - 1);
 308       if (len != 0)
 309         {
 310           if (bfd_bwrite (pad, len, abfd) != len)
 311             goto err;
 312           off += len;
 313         }
 314
 315       str = entry->root.string;
 316       len = entry->len;
 317
 318       if (bfd_bwrite (str, len, abfd) != len)
 319         goto err;
 320
 321       off += len;
 322     }
 323
 324   /* Trailing alignment needed?  */
 325   off = sec->size - off;
 326   if (off != 0
 327       && bfd_bwrite (pad, off, abfd) != off)
 328     goto err;
 329
 330   if (pad != NULL)
 331     free (pad);
 332   return TRUE;
 333
 334  err:
 335   if (pad != NULL)
 336     free (pad);
 337   return FALSE;
 338 }
 339
 340 /* Register a SEC_MERGE section as a candidate for merging.
 341    This function is called for all non-dynamic SEC_MERGE input sections.  */
 342
 343 bfd_boolean
 344 _bfd_add_merge_section (bfd *abfd, void **psinfo, asection *sec,
 345                         void **psecinfo)
 346 {
 347   struct sec_merge_info *sinfo;
 348   struct sec_merge_sec_info *secinfo;
 349   unsigned int align;
 350   bfd_size_type amt;
 351
 352   if ((abfd->flags & DYNAMIC) != 0
 353       || (sec->flags & SEC_MERGE) == 0)
 354     abort ();
 355
 356   if (sec->size == 0
 357       || (sec->flags & SEC_EXCLUDE) != 0
 358       || sec->entsize == 0)
 359     return TRUE;
 360
 361   if ((sec->flags & SEC_RELOC) != 0)
 362     {
 363       /* We aren't prepared to handle relocations in merged sections.  */
 364       return TRUE;
 365     }
 366
 367   align = sec->alignment_power;
 368   if ((sec->entsize < (unsigned) 1 << align
 369        && ((sec->entsize & (sec->entsize - 1))
 370            || !(sec->flags & SEC_STRINGS)))
 371       || (sec->entsize > (unsigned) 1 << align
 372           && (sec->entsize & (((unsigned) 1 << align) - 1))))
 373     {
 374       /* Sanity check.  If string character size is smaller than
 375          alignment, then we require character size to be a power
 376          of 2, otherwise character size must be integer multiple
 377          of alignment.  For non-string constants, alignment must
 378          be smaller than or equal to entity size and entity size
 379          must be integer multiple of alignment.  */
 380       return TRUE;
 381     }
 382
 383   for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next)
 384     if ((secinfo = sinfo->chain)
 385         && ! ((secinfo->sec->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS))
 386         && secinfo->sec->entsize == sec->entsize
 387         && secinfo->sec->alignment_power == sec->alignment_power
 388         && secinfo->sec->output_section == sec->output_section)
 389       break;
 390
 391   if (sinfo == NULL)
 392     {
 393       /* Initialize the information we need to keep track of.  */
 394       sinfo = bfd_alloc (abfd, sizeof (struct sec_merge_info));
 395       if (sinfo == NULL)
 396         goto error_return;
 397       sinfo->next = (struct sec_merge_info *) *psinfo;
 398       sinfo->chain = NULL;
 399       *psinfo = sinfo;
 400       sinfo->htab = sec_merge_init (sec->entsize, (sec->flags & SEC_STRINGS));
 401       if (sinfo->htab == NULL)
 402         goto error_return;
 403     }
 404
 405   /* Read the section from abfd.  */
 406
 407   amt = sizeof (struct sec_merge_sec_info) + sec->size - 1;
 408   *psecinfo = bfd_alloc (abfd, amt);
 409   if (*psecinfo == NULL)
 410     goto error_return;
 411
 412   secinfo = (struct sec_merge_sec_info *) *psecinfo;
 413   if (sinfo->chain)
 414     {
 415       secinfo->next = sinfo->chain->next;
 416       sinfo->chain->next = secinfo;
 417     }
 418   else
 419     secinfo->next = secinfo;
 420   sinfo->chain = secinfo;
 421   secinfo->sec = sec;
 422   secinfo->psecinfo = psecinfo;
 423   secinfo->htab = sinfo->htab;
 424   secinfo->first_str = NULL;
 425
 426   sec->rawsize = sec->size;
 427   if (! bfd_get_section_contents (sec->owner, sec, secinfo->contents,
 428                                   0, sec->size))
 429     goto error_return;
 430
 431   return TRUE;
 432
 433  error_return:
 434   *psecinfo = NULL;
 435   return FALSE;
 436 }
 437
 438 /* Record one section into the hash table.  */
 439 static bfd_boolean
 440 record_section (struct sec_merge_info *sinfo,
 441                 struct sec_merge_sec_info *secinfo)
 442 {
 443   asection *sec = secinfo->sec;
 444   struct sec_merge_hash_entry *entry;
 445   bfd_boolean nul;
 446   unsigned char *p, *end;
 447   bfd_vma mask, eltalign;
 448   unsigned int align, i;
 449
 450   align = sec->alignment_power;
 451   end = secinfo->contents + sec->size;
 452   nul = FALSE;
 453   mask = ((bfd_vma) 1 << align) - 1;
 454   if (sec->flags & SEC_STRINGS)
 455     {
 456       for (p = secinfo->contents; p < end; )
 457         {
 458           eltalign = p - secinfo->contents;
 459           eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1;
 460           if (!eltalign || eltalign > mask)
 461             eltalign = mask + 1;
 462           entry = sec_merge_add (sinfo->htab, (char *) p, (unsigned) eltalign,
 463                                  secinfo);
 464           if (! entry)
 465             goto error_return;
 466           p += entry->len;
 467           if (sec->entsize == 1)
 468             {
 469               while (p < end && *p == 0)
 470                 {
 471                   if (!nul && !((p - secinfo->contents) & mask))
 472                     {
 473                       nul = TRUE;
 474                       entry = sec_merge_add (sinfo->htab, "",
 475                                              (unsigned) mask + 1, secinfo);
 476                       if (! entry)
 477                         goto error_return;
 478                     }
 479                   p++;
 480                 }
 481             }
 482           else
 483             {
 484               while (p < end)
 485                 {
 486                   for (i = 0; i < sec->entsize; i++)
 487                     if (p[i] != '\0')
 488                       break;
 489                   if (i != sec->entsize)
 490                     break;
 491                   if (!nul && !((p - secinfo->contents) & mask))
 492                     {
 493                       nul = TRUE;
 494                       entry = sec_merge_add (sinfo->htab, (char *) p,
 495                                              (unsigned) mask + 1, secinfo);
 496                       if (! entry)
 497                         goto error_return;
 498                     }
 499                   p += sec->entsize;
 500                 }
 501             }
 502         }
 503     }
 504   else
 505     {
 506       for (p = secinfo->contents; p < end; p += sec->entsize)
 507         {
 508           entry = sec_merge_add (sinfo->htab, (char *) p, 1, secinfo);
 509           if (! entry)
 510             goto error_return;
 511         }
 512     }
 513
 514   return TRUE;
 515
 516 error_return:
 517   for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 518     *secinfo->psecinfo = NULL;
 519   return FALSE;
 520 }
 521
 522 static int
 523 strrevcmp (const void *a, const void *b)
 524 {
 525   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 526   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 527   unsigned int lenA = A->len;
 528   unsigned int lenB = B->len;
 529   const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
 530   const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
 531   int l = lenA < lenB ? lenA : lenB;
 532
 533   while (l)
 534     {
 535       if (*s != *t)
 536         return (int) *s - (int) *t;
 537       s--;
 538       t--;
 539       l--;
 540     }
 541   return lenA - lenB;
 542 }
 543
 544 /* Like strrevcmp, but for the case where all strings have the same
 545    alignment > entsize.  */
 546
 547 static int
 548 strrevcmp_align (const void *a, const void *b)
 549 {
 550   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 551   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 552   unsigned int lenA = A->len;
 553   unsigned int lenB = B->len;
 554   const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
 555   const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
 556   int l = lenA < lenB ? lenA : lenB;
 557   int tail_align = (lenA & (A->alignment - 1)) - (lenB & (A->alignment - 1));
 558
 559   if (tail_align != 0)
 560     return tail_align;
 561
 562   while (l)
 563     {
 564       if (*s != *t)
 565         return (int) *s - (int) *t;
 566       s--;
 567       t--;
 568       l--;
 569     }
 570   return lenA - lenB;
 571 }
 572
 573 static inline int
 574 is_suffix (const struct sec_merge_hash_entry *A,
 575            const struct sec_merge_hash_entry *B)
 576 {
 577   if (A->len <= B->len)
 578     /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
 579        not to be equal by the hash table.  */
 580     return 0;
 581
 582   return memcmp (A->root.string + (A->len - B->len),
 583                  B->root.string, B->len) == 0;
 584 }
 585
 586 /* This is a helper function for _bfd_merge_sections.  It attempts to
 587    merge strings matching suffixes of longer strings.  */
 588 static void
 589 merge_strings (struct sec_merge_info *sinfo)
 590 {
 591   struct sec_merge_hash_entry **array, **a, *e;
 592   struct sec_merge_sec_info *secinfo;
 593   bfd_size_type size, amt;
 594   unsigned int alignment = 0;
 595
 596   /* Now sort the strings */
 597   amt = sinfo->htab->size * sizeof (struct sec_merge_hash_entry *);
 598   array = bfd_malloc (amt);
 599   if (array == NULL)
 600     goto alloc_failure;
 601
 602   for (e = sinfo->htab->first, a = array; e; e = e->next)
 603     if (e->alignment)
 604       {
 605         *a++ = e;
 606         /* Adjust the length to not include the zero terminator.  */
 607         e->len -= sinfo->htab->entsize;
 608         if (alignment != e->alignment)
 609           {
 610             if (alignment == 0)
 611               alignment = e->alignment;
 612             else
 613               alignment = (unsigned) -1;
 614           }
 615       }
 616
 617   sinfo->htab->size = a - array;
 618   if (sinfo->htab->size != 0)
 619     {
 620       qsort (array, (size_t) sinfo->htab->size,
 621              sizeof (struct sec_merge_hash_entry *),
 622              (alignment != (unsigned) -1 && alignment > sinfo->htab->entsize
 623               ? strrevcmp_align : strrevcmp));
 624
 625       /* Loop over the sorted array and merge suffixes */
 626       e = *--a;
 627       e->len += sinfo->htab->entsize;
 628       while (--a >= array)
 629         {
 630           struct sec_merge_hash_entry *cmp = *a;
 631
 632           cmp->len += sinfo->htab->entsize;
 633           if (e->alignment >= cmp->alignment
 634               && !((e->len - cmp->len) & (cmp->alignment - 1))
 635               && is_suffix (e, cmp))
 636             {
 637               cmp->u.suffix = e;
 638               cmp->alignment = 0;
 639             }
 640           else
 641             e = cmp;
 642         }
 643     }
 644
 645 alloc_failure:
 646   if (array)
 647     free (array);
 648
 649   /* Now assign positions to the strings we want to keep.  */
 650   size = 0;
 651   secinfo = sinfo->htab->first->secinfo;
 652   for (e = sinfo->htab->first; e; e = e->next)
 653     {
 654       if (e->secinfo != secinfo)
 655         {
 656           secinfo->sec->size = size;
 657           secinfo = e->secinfo;
 658         }
 659       if (e->alignment)
 660         {
 661           if (e->secinfo->first_str == NULL)
 662             {
 663               e->secinfo->first_str = e;
 664               size = 0;
 665             }
 666           size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
 667           e->u.index = size;
 668           size += e->len;
 669         }
 670     }
 671   secinfo->sec->size = size;
 672   if (secinfo->sec->alignment_power != 0)
 673     {
 674       bfd_size_type align = (bfd_size_type) 1 << secinfo->sec->alignment_power;
 675       secinfo->sec->size = (secinfo->sec->size + align - 1) & -align;
 676     }
 677
 678   /* And now adjust the rest, removing them from the chain (but not hashtable)
 679      at the same time.  */
 680   for (a = &sinfo->htab->first, e = *a; e; e = e->next)
 681     if (e->alignment)
 682       a = &e->next;
 683     else
 684       {
 685         *a = e->next;
 686         if (e->len)
 687           {
 688             e->secinfo = e->u.suffix->secinfo;
 689             e->alignment = e->u.suffix->alignment;
 690             e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len);
 691           }
 692       }
 693 }
 694
 695 /* This function is called once after all SEC_MERGE sections are registered
 696    with _bfd_merge_section.  */
 697
 698 bfd_boolean
 699 _bfd_merge_sections (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_link_info *info,
 700                      void *xsinfo, void (*remove_hook) (bfd *, asection *))
 701 {
 702   struct sec_merge_info *sinfo;
 703
 704   for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
 705     {
 706       struct sec_merge_sec_info * secinfo;
 707
 708       if (! sinfo->chain)
 709         continue;
 710
 711       /* Move sinfo->chain to head of the chain, terminate it.  */
 712       secinfo = sinfo->chain;
 713       sinfo->chain = secinfo->next;
 714       secinfo->next = NULL;
 715
 716       /* Record the sections into the hash table.  */
 717       for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 718         if (secinfo->sec->flags & SEC_EXCLUDE)
 719           {
 720             *secinfo->psecinfo = NULL;
 721             if (remove_hook)
 722               (*remove_hook) (abfd, secinfo->sec);
 723           }
 724         else if (! record_section (sinfo, secinfo))
 725           break;
 726
 727       if (secinfo)
 728         continue;
 729
 730       if (sinfo->htab->first == NULL)
 731         continue;
 732
 733       if (sinfo->htab->strings)
 734         merge_strings (sinfo);
 735       else
 736         {
 737           struct sec_merge_hash_entry *e;
 738           bfd_size_type size = 0;
 739
 740           /* Things are much simpler for non-strings.
 741              Just assign them slots in the section.  */
 742           secinfo = NULL;
 743           for (e = sinfo->htab->first; e; e = e->next)
 744             {
 745               if (e->secinfo->first_str == NULL)
 746                 {
 747                   if (secinfo)
 748                     secinfo->sec->size = size;
 749                   e->secinfo->first_str = e;
 750                   size = 0;
 751                 }
 752               size = (size + e->alignment - 1)
 753                      & ~((bfd_vma) e->alignment - 1);
 754               e->u.index = size;
 755               size += e->len;
 756               secinfo = e->secinfo;
 757             }
 758           secinfo->sec->size = size;
 759         }
 760
 761         /* Finally remove all input sections which have not made it into
 762            the hash table at all.  */
 763         for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 764           if (secinfo->first_str == NULL)
 765             _bfd_strip_section_from_output (info, secinfo->sec);
 766     }
 767
 768   return TRUE;
 769 }
 770
 771 /* Write out the merged section.  */
 772
 773 bfd_boolean
 774 _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
 775 {
 776   struct sec_merge_sec_info *secinfo;
 777   file_ptr pos;
 778
 779   secinfo = (struct sec_merge_sec_info *) psecinfo;
 780
 781   if (secinfo->first_str == NULL)
 782     return TRUE;
 783
 784   pos = sec->output_section->filepos + sec->output_offset;
 785   if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
 786     return FALSE;
 787
 788   if (! sec_merge_emit (output_bfd, secinfo->first_str))
 789     return FALSE;
 790
 791   return TRUE;
 792 }
 793
 794 /* Adjust an address in the SEC_MERGE section.  Given OFFSET within
 795    *PSEC, this returns the new offset in the adjusted SEC_MERGE
 796    section and writes the new section back into *PSEC.  */
 797
 798 bfd_vma
 799 _bfd_merged_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, asection **psec,
 800                             void *psecinfo, bfd_vma offset)
 801 {
 802   struct sec_merge_sec_info *secinfo;
 803   struct sec_merge_hash_entry *entry;
 804   unsigned char *p;
 805   asection *sec = *psec;
 806
 807   secinfo = (struct sec_merge_sec_info *) psecinfo;
 808
 809   if (offset >= sec->rawsize)
 810     {
 811       if (offset > sec->rawsize)
 812         {
 813           (*_bfd_error_handler)
 814             (_("%s: access beyond end of merged section (%ld)"),
 815              bfd_get_filename (sec->owner), (long) offset);
 816         }
 817       return secinfo->first_str ? sec->size : 0;
 818     }
 819
 820   if (secinfo->htab->strings)
 821     {
 822       if (sec->entsize == 1)
 823         {
 824           p = secinfo->contents + offset - 1;
 825           while (p >= secinfo->contents && *p)
 826             --p;
 827           ++p;
 828         }
 829       else
 830         {
 831           p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 832           p -= sec->entsize;
 833           while (p >= secinfo->contents)
 834             {
 835               unsigned int i;
 836
 837               for (i = 0; i < sec->entsize; ++i)
 838                 if (p[i] != '\0')
 839                   break;
 840               if (i == sec->entsize)
 841                 break;
 842               p -= sec->entsize;
 843             }
 844           p += sec->entsize;
 845         }
 846     }
 847   else
 848     {
 849       p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 850     }
 851   entry = sec_merge_hash_lookup (secinfo->htab, (char *) p, 0, FALSE);
 852   if (!entry)
 853     {
 854       if (! secinfo->htab->strings)
 855         abort ();
 856       /* This should only happen if somebody points into the padding
 857          after a NUL character but before next entity.  */
 858       if (*p)
 859         abort ();
 860       if (! secinfo->htab->first)
 861         abort ();
 862       entry = secinfo->htab->first;
 863       p = (secinfo->contents + (offset / sec->entsize + 1) * sec->entsize
 864            - entry->len);
 865     }
 866
 867   *psec = entry->secinfo->sec;
 868   return entry->u.index + (secinfo->contents + offset - p);
 869 }