bfd/merge.c

   1 /* SEC_MERGE support.
   2    Copyright 2001, 2002, 2003 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 = "";
 292   bfd_size_type off = 0;
 293   int alignment_power = sec->output_section->alignment_power;
 294
 295   if (alignment_power)
 296     pad = bfd_zmalloc ((bfd_size_type) 1 << alignment_power);
 297
 298   for (; entry != NULL && entry->secinfo == secinfo; entry = entry->next)
 299     {
 300       register const char *str;
 301       register size_t len;
 302
 303       len = off & (entry->alignment - 1);
 304       if (len)
 305         {
 306           len = entry->alignment - len;
 307           if (bfd_bwrite (pad, len, abfd) != len)
 308             break;
 309           off += len;
 310         }
 311
 312       str = entry->root.string;
 313       len = entry->len;
 314
 315       if (bfd_bwrite (str, len, abfd) != len)
 316         break;
 317
 318       off += len;
 319     }
 320
 321   if (alignment_power)
 322     free (pad);
 323
 324   return entry == NULL || entry->secinfo != secinfo;
 325 }
 326
 327 /* Register a SEC_MERGE section as a candidate for merging.
 328    This function is called for all non-dynamic SEC_MERGE input sections.  */
 329
 330 bfd_boolean
 331 _bfd_add_merge_section (bfd *abfd, void **psinfo, asection *sec,
 332                         void **psecinfo)
 333 {
 334   struct sec_merge_info *sinfo;
 335   struct sec_merge_sec_info *secinfo;
 336   unsigned int align;
 337   bfd_size_type amt;
 338
 339   if ((abfd->flags & DYNAMIC) != 0
 340       || (sec->flags & SEC_MERGE) == 0)
 341     abort ();
 342
 343   if (sec->_raw_size == 0
 344       || (sec->flags & SEC_EXCLUDE) != 0
 345       || sec->entsize == 0)
 346     return TRUE;
 347
 348   if ((sec->flags & SEC_RELOC) != 0)
 349     {
 350       /* We aren't prepared to handle relocations in merged sections.  */
 351       return TRUE;
 352     }
 353
 354   align = sec->alignment_power;
 355   if ((sec->entsize < (unsigned) 1 << align
 356        && ((sec->entsize & (sec->entsize - 1))
 357            || !(sec->flags & SEC_STRINGS)))
 358       || (sec->entsize > (unsigned) 1 << align
 359           && (sec->entsize & (((unsigned) 1 << align) - 1))))
 360     {
 361       /* Sanity check.  If string character size is smaller than
 362          alignment, then we require character size to be a power
 363          of 2, otherwise character size must be integer multiple
 364          of alignment.  For non-string constants, alignment must
 365          be smaller than or equal to entity size and entity size
 366          must be integer multiple of alignment.  */
 367       return TRUE;
 368     }
 369
 370   for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next)
 371     if ((secinfo = sinfo->chain)
 372         && ! ((secinfo->sec->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS))
 373         && secinfo->sec->entsize == sec->entsize
 374         && secinfo->sec->alignment_power == sec->alignment_power
 375         && secinfo->sec->output_section == sec->output_section)
 376       break;
 377
 378   if (sinfo == NULL)
 379     {
 380       /* Initialize the information we need to keep track of.  */
 381       sinfo = bfd_alloc (abfd, sizeof (struct sec_merge_info));
 382       if (sinfo == NULL)
 383         goto error_return;
 384       sinfo->next = (struct sec_merge_info *) *psinfo;
 385       sinfo->chain = NULL;
 386       *psinfo = sinfo;
 387       sinfo->htab = sec_merge_init (sec->entsize, (sec->flags & SEC_STRINGS));
 388       if (sinfo->htab == NULL)
 389         goto error_return;
 390     }
 391
 392   /* Read the section from abfd.  */
 393
 394   amt = sizeof (struct sec_merge_sec_info) + sec->_raw_size - 1;
 395   *psecinfo = bfd_alloc (abfd, amt);
 396   if (*psecinfo == NULL)
 397     goto error_return;
 398
 399   secinfo = (struct sec_merge_sec_info *) *psecinfo;
 400   if (sinfo->chain)
 401     {
 402       secinfo->next = sinfo->chain->next;
 403       sinfo->chain->next = secinfo;
 404     }
 405   else
 406     secinfo->next = secinfo;
 407   sinfo->chain = secinfo;
 408   secinfo->sec = sec;
 409   secinfo->psecinfo = psecinfo;
 410   secinfo->htab = sinfo->htab;
 411   secinfo->first_str = NULL;
 412
 413   if (! bfd_get_section_contents (sec->owner, sec, secinfo->contents,
 414                                   0, sec->_raw_size))
 415     goto error_return;
 416
 417   return TRUE;
 418
 419  error_return:
 420   *psecinfo = NULL;
 421   return FALSE;
 422 }
 423
 424 /* Record one section into the hash table.  */
 425 static bfd_boolean
 426 record_section (struct sec_merge_info *sinfo,
 427                 struct sec_merge_sec_info *secinfo)
 428 {
 429   asection *sec = secinfo->sec;
 430   struct sec_merge_hash_entry *entry;
 431   bfd_boolean nul;
 432   unsigned char *p, *end;
 433   bfd_vma mask, eltalign;
 434   unsigned int align, i;
 435
 436   align = sec->alignment_power;
 437   end = secinfo->contents + sec->_raw_size;
 438   nul = FALSE;
 439   mask = ((bfd_vma) 1 << align) - 1;
 440   if (sec->flags & SEC_STRINGS)
 441     {
 442       for (p = secinfo->contents; p < end; )
 443         {
 444           eltalign = p - secinfo->contents;
 445           eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1;
 446           if (!eltalign || eltalign > mask)
 447             eltalign = mask + 1;
 448           entry = sec_merge_add (sinfo->htab, p, (unsigned) eltalign, secinfo);
 449           if (! entry)
 450             goto error_return;
 451           p += entry->len;
 452           if (sec->entsize == 1)
 453             {
 454               while (p < end && *p == 0)
 455                 {
 456                   if (!nul && !((p - secinfo->contents) & mask))
 457                     {
 458                       nul = TRUE;
 459                       entry = sec_merge_add (sinfo->htab, "",
 460                                              (unsigned) mask + 1, secinfo);
 461                       if (! entry)
 462                         goto error_return;
 463                     }
 464                   p++;
 465                 }
 466             }
 467           else
 468             {
 469               while (p < end)
 470                 {
 471                   for (i = 0; i < sec->entsize; i++)
 472                     if (p[i] != '\0')
 473                       break;
 474                   if (i != sec->entsize)
 475                     break;
 476                   if (!nul && !((p - secinfo->contents) & mask))
 477                     {
 478                       nul = TRUE;
 479                       entry = sec_merge_add (sinfo->htab, p,
 480                                              (unsigned) mask + 1, secinfo);
 481                       if (! entry)
 482                         goto error_return;
 483                     }
 484                   p += sec->entsize;
 485                 }
 486             }
 487         }
 488     }
 489   else
 490     {
 491       for (p = secinfo->contents; p < end; p += sec->entsize)
 492         {
 493           entry = sec_merge_add (sinfo->htab, p, 1, secinfo);
 494           if (! entry)
 495             goto error_return;
 496         }
 497     }
 498
 499   return TRUE;
 500
 501 error_return:
 502   for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 503     *secinfo->psecinfo = NULL;
 504   return FALSE;
 505 }
 506
 507 static int
 508 strrevcmp (const void *a, const void *b)
 509 {
 510   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 511   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 512   unsigned int lenA = A->len;
 513   unsigned int lenB = B->len;
 514   const unsigned char *s = A->root.string + lenA - 1;
 515   const unsigned char *t = B->root.string + lenB - 1;
 516   int l = lenA < lenB ? lenA : lenB;
 517
 518   while (l)
 519     {
 520       if (*s != *t)
 521         return (int) *s - (int) *t;
 522       s--;
 523       t--;
 524       l--;
 525     }
 526   return lenA - lenB;
 527 }
 528
 529 /* Like strrevcmp, but for the case where all strings have the same
 530    alignment > entsize.  */
 531
 532 static int
 533 strrevcmp_align (const void *a, const void *b)
 534 {
 535   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 536   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 537   unsigned int lenA = A->len;
 538   unsigned int lenB = B->len;
 539   const unsigned char *s = A->root.string + lenA - 1;
 540   const unsigned char *t = B->root.string + lenB - 1;
 541   int l = lenA < lenB ? lenA : lenB;
 542   int tail_align = (lenA & (A->alignment - 1)) - (lenB & (A->alignment - 1));
 543
 544   if (tail_align != 0)
 545     return tail_align;
 546
 547   while (l)
 548     {
 549       if (*s != *t)
 550         return (int) *s - (int) *t;
 551       s--;
 552       t--;
 553       l--;
 554     }
 555   return lenA - lenB;
 556 }
 557
 558 static inline int
 559 is_suffix (const struct sec_merge_hash_entry *A,
 560            const struct sec_merge_hash_entry *B)
 561 {
 562   if (A->len <= B->len)
 563     /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
 564        not to be equal by the hash table.  */
 565     return 0;
 566
 567   return memcmp (A->root.string + (A->len - B->len),
 568                  B->root.string, B->len) == 0;
 569 }
 570
 571 /* This is a helper function for _bfd_merge_sections.  It attempts to
 572    merge strings matching suffixes of longer strings.  */
 573 static void
 574 merge_strings (struct sec_merge_info *sinfo)
 575 {
 576   struct sec_merge_hash_entry **array, **a, *e;
 577   struct sec_merge_sec_info *secinfo;
 578   bfd_size_type size, amt;
 579   unsigned int alignment = 0;
 580
 581   /* Now sort the strings */
 582   amt = sinfo->htab->size * sizeof (struct sec_merge_hash_entry *);
 583   array = bfd_malloc (amt);
 584   if (array == NULL)
 585     goto alloc_failure;
 586
 587   for (e = sinfo->htab->first, a = array; e; e = e->next)
 588     if (e->alignment)
 589       {
 590         *a++ = e;
 591         /* Adjust the length to not include the zero terminator.  */
 592         e->len -= sinfo->htab->entsize;
 593         if (alignment != e->alignment)
 594           {
 595             if (alignment == 0)
 596               alignment = e->alignment;
 597             else
 598               alignment = (unsigned) -1;
 599           }
 600       }
 601
 602   sinfo->htab->size = a - array;
 603   if (sinfo->htab->size != 0)
 604     {
 605       qsort (array, (size_t) sinfo->htab->size,
 606              sizeof (struct sec_merge_hash_entry *),
 607              (alignment != (unsigned) -1 && alignment > sinfo->htab->entsize
 608               ? strrevcmp_align : strrevcmp));
 609
 610       /* Loop over the sorted array and merge suffixes */
 611       e = *--a;
 612       e->len += sinfo->htab->entsize;
 613       while (--a >= array)
 614         {
 615           struct sec_merge_hash_entry *cmp = *a;
 616
 617           cmp->len += sinfo->htab->entsize;
 618           if (e->alignment >= cmp->alignment
 619               && !((e->len - cmp->len) & (cmp->alignment - 1))
 620               && is_suffix (e, cmp))
 621             {
 622               cmp->u.suffix = e;
 623               cmp->alignment = 0;
 624             }
 625           else
 626             e = cmp;
 627         }
 628     }
 629
 630 alloc_failure:
 631   if (array)
 632     free (array);
 633
 634   /* Now assign positions to the strings we want to keep.  */
 635   size = 0;
 636   secinfo = sinfo->htab->first->secinfo;
 637   for (e = sinfo->htab->first; e; e = e->next)
 638     {
 639       if (e->secinfo != secinfo)
 640         {
 641           secinfo->sec->_cooked_size = size;
 642           secinfo = e->secinfo;
 643         }
 644       if (e->alignment)
 645         {
 646           if (e->secinfo->first_str == NULL)
 647             {
 648               e->secinfo->first_str = e;
 649               size = 0;
 650             }
 651           size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
 652           e->u.index = size;
 653           size += e->len;
 654         }
 655     }
 656   secinfo->sec->_cooked_size = size;
 657
 658   /* And now adjust the rest, removing them from the chain (but not hashtable)
 659      at the same time.  */
 660   for (a = &sinfo->htab->first, e = *a; e; e = e->next)
 661     if (e->alignment)
 662       a = &e->next;
 663     else
 664       {
 665         *a = e->next;
 666         if (e->len)
 667           {
 668             e->secinfo = e->u.suffix->secinfo;
 669             e->alignment = e->u.suffix->alignment;
 670             e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len);
 671           }
 672       }
 673 }
 674
 675 /* This function is called once after all SEC_MERGE sections are registered
 676    with _bfd_merge_section.  */
 677
 678 bfd_boolean
 679 _bfd_merge_sections (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_link_info *info,
 680                      void *xsinfo, void (*remove_hook) (bfd *, asection *))
 681 {
 682   struct sec_merge_info *sinfo;
 683
 684   for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
 685     {
 686       struct sec_merge_sec_info * secinfo;
 687
 688       if (! sinfo->chain)
 689         continue;
 690
 691       /* Move sinfo->chain to head of the chain, terminate it.  */
 692       secinfo = sinfo->chain;
 693       sinfo->chain = secinfo->next;
 694       secinfo->next = NULL;
 695
 696       /* Record the sections into the hash table.  */
 697       for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 698         if (secinfo->sec->flags & SEC_EXCLUDE)
 699           {
 700             *secinfo->psecinfo = NULL;
 701             if (remove_hook)
 702               (*remove_hook) (abfd, secinfo->sec);
 703           }
 704         else if (! record_section (sinfo, secinfo))
 705           break;
 706
 707       if (secinfo)
 708         continue;
 709
 710       if (sinfo->htab->first == NULL)
 711         continue;
 712
 713       if (sinfo->htab->strings)
 714         merge_strings (sinfo);
 715       else
 716         {
 717           struct sec_merge_hash_entry *e;
 718           bfd_size_type size = 0;
 719
 720           /* Things are much simpler for non-strings.
 721              Just assign them slots in the section.  */
 722           secinfo = NULL;
 723           for (e = sinfo->htab->first; e; e = e->next)
 724             {
 725               if (e->secinfo->first_str == NULL)
 726                 {
 727                   if (secinfo)
 728                     secinfo->sec->_cooked_size = size;
 729                   e->secinfo->first_str = e;
 730                   size = 0;
 731                 }
 732               size = (size + e->alignment - 1)
 733                      & ~((bfd_vma) e->alignment - 1);
 734               e->u.index = size;
 735               size += e->len;
 736               secinfo = e->secinfo;
 737             }
 738           secinfo->sec->_cooked_size = size;
 739         }
 740
 741         /* Finally remove all input sections which have not made it into
 742            the hash table at all.  */
 743         for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 744           if (secinfo->first_str == NULL)
 745             _bfd_strip_section_from_output (info, secinfo->sec);
 746     }
 747
 748   return TRUE;
 749 }
 750
 751 /* Write out the merged section.  */
 752
 753 bfd_boolean
 754 _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
 755 {
 756   struct sec_merge_sec_info *secinfo;
 757   file_ptr pos;
 758
 759   secinfo = (struct sec_merge_sec_info *) psecinfo;
 760
 761   if (secinfo->first_str == NULL)
 762     return TRUE;
 763
 764   pos = sec->output_section->filepos + sec->output_offset;
 765   if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
 766     return FALSE;
 767
 768   if (! sec_merge_emit (output_bfd, secinfo->first_str))
 769     return FALSE;
 770
 771   return TRUE;
 772 }
 773
 774 /* Adjust an address in the SEC_MERGE section.  Given OFFSET within
 775    *PSEC, this returns the new offset in the adjusted SEC_MERGE
 776    section and writes the new section back into *PSEC.  */
 777
 778 bfd_vma
 779 _bfd_merged_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, asection **psec,
 780                             void *psecinfo, bfd_vma offset)
 781 {
 782   struct sec_merge_sec_info *secinfo;
 783   struct sec_merge_hash_entry *entry;
 784   unsigned char *p;
 785   asection *sec = *psec;
 786
 787   secinfo = (struct sec_merge_sec_info *) psecinfo;
 788
 789   if (offset >= sec->_raw_size)
 790     {
 791       if (offset > sec->_raw_size)
 792         {
 793           (*_bfd_error_handler)
 794             (_("%s: access beyond end of merged section (%ld)"),
 795              bfd_get_filename (sec->owner), (long) offset);
 796         }
 797       return (secinfo->first_str ? sec->_cooked_size : 0);
 798     }
 799
 800   if (secinfo->htab->strings)
 801     {
 802       if (sec->entsize == 1)
 803         {
 804           p = secinfo->contents + offset - 1;
 805           while (p >= secinfo->contents && *p)
 806             --p;
 807           ++p;
 808         }
 809       else
 810         {
 811           p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 812           p -= sec->entsize;
 813           while (p >= secinfo->contents)
 814             {
 815               unsigned int i;
 816
 817               for (i = 0; i < sec->entsize; ++i)
 818                 if (p[i] != '\0')
 819                   break;
 820               if (i == sec->entsize)
 821                 break;
 822               p -= sec->entsize;
 823             }
 824           p += sec->entsize;
 825         }
 826     }
 827   else
 828     {
 829       p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 830     }
 831   entry = sec_merge_hash_lookup (secinfo->htab, p, 0, FALSE);
 832   if (!entry)
 833     {
 834       if (! secinfo->htab->strings)
 835         abort ();
 836       /* This should only happen if somebody points into the padding
 837          after a NUL character but before next entity.  */
 838       if (*p)
 839         abort ();
 840       if (! secinfo->htab->first)
 841         abort ();
 842       entry = secinfo->htab->first;
 843       p = (secinfo->contents + (offset / sec->entsize + 1) * sec->entsize
 844            - entry->len);
 845     }
 846
 847   *psec = entry->secinfo->sec;
 848   return entry->u.index + (secinfo->contents + offset - p);
 849 }