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 = "";
 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->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->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   sec->rawsize = sec->size;
 414   if (! bfd_get_section_contents (sec->owner, sec, secinfo->contents,
 415                                   0, sec->size))
 416     goto error_return;
 417
 418   return TRUE;
 419
 420  error_return:
 421   *psecinfo = NULL;
 422   return FALSE;
 423 }
 424
 425 /* Record one section into the hash table.  */
 426 static bfd_boolean
 427 record_section (struct sec_merge_info *sinfo,
 428                 struct sec_merge_sec_info *secinfo)
 429 {
 430   asection *sec = secinfo->sec;
 431   struct sec_merge_hash_entry *entry;
 432   bfd_boolean nul;
 433   unsigned char *p, *end;
 434   bfd_vma mask, eltalign;
 435   unsigned int align, i;
 436
 437   align = sec->alignment_power;
 438   end = secinfo->contents + sec->size;
 439   nul = FALSE;
 440   mask = ((bfd_vma) 1 << align) - 1;
 441   if (sec->flags & SEC_STRINGS)
 442     {
 443       for (p = secinfo->contents; p < end; )
 444         {
 445           eltalign = p - secinfo->contents;
 446           eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1;
 447           if (!eltalign || eltalign > mask)
 448             eltalign = mask + 1;
 449           entry = sec_merge_add (sinfo->htab, (char *) p, (unsigned) eltalign,
 450                                  secinfo);
 451           if (! entry)
 452             goto error_return;
 453           p += entry->len;
 454           if (sec->entsize == 1)
 455             {
 456               while (p < end && *p == 0)
 457                 {
 458                   if (!nul && !((p - secinfo->contents) & mask))
 459                     {
 460                       nul = TRUE;
 461                       entry = sec_merge_add (sinfo->htab, "",
 462                                              (unsigned) mask + 1, secinfo);
 463                       if (! entry)
 464                         goto error_return;
 465                     }
 466                   p++;
 467                 }
 468             }
 469           else
 470             {
 471               while (p < end)
 472                 {
 473                   for (i = 0; i < sec->entsize; i++)
 474                     if (p[i] != '\0')
 475                       break;
 476                   if (i != sec->entsize)
 477                     break;
 478                   if (!nul && !((p - secinfo->contents) & mask))
 479                     {
 480                       nul = TRUE;
 481                       entry = sec_merge_add (sinfo->htab, (char *) p,
 482                                              (unsigned) mask + 1, secinfo);
 483                       if (! entry)
 484                         goto error_return;
 485                     }
 486                   p += sec->entsize;
 487                 }
 488             }
 489         }
 490     }
 491   else
 492     {
 493       for (p = secinfo->contents; p < end; p += sec->entsize)
 494         {
 495           entry = sec_merge_add (sinfo->htab, (char *) p, 1, secinfo);
 496           if (! entry)
 497             goto error_return;
 498         }
 499     }
 500
 501   return TRUE;
 502
 503 error_return:
 504   for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 505     *secinfo->psecinfo = NULL;
 506   return FALSE;
 507 }
 508
 509 static int
 510 strrevcmp (const void *a, const void *b)
 511 {
 512   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 513   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 514   unsigned int lenA = A->len;
 515   unsigned int lenB = B->len;
 516   const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
 517   const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
 518   int l = lenA < lenB ? lenA : lenB;
 519
 520   while (l)
 521     {
 522       if (*s != *t)
 523         return (int) *s - (int) *t;
 524       s--;
 525       t--;
 526       l--;
 527     }
 528   return lenA - lenB;
 529 }
 530
 531 /* Like strrevcmp, but for the case where all strings have the same
 532    alignment > entsize.  */
 533
 534 static int
 535 strrevcmp_align (const void *a, const void *b)
 536 {
 537   struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
 538   struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
 539   unsigned int lenA = A->len;
 540   unsigned int lenB = B->len;
 541   const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
 542   const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
 543   int l = lenA < lenB ? lenA : lenB;
 544   int tail_align = (lenA & (A->alignment - 1)) - (lenB & (A->alignment - 1));
 545
 546   if (tail_align != 0)
 547     return tail_align;
 548
 549   while (l)
 550     {
 551       if (*s != *t)
 552         return (int) *s - (int) *t;
 553       s--;
 554       t--;
 555       l--;
 556     }
 557   return lenA - lenB;
 558 }
 559
 560 static inline int
 561 is_suffix (const struct sec_merge_hash_entry *A,
 562            const struct sec_merge_hash_entry *B)
 563 {
 564   if (A->len <= B->len)
 565     /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
 566        not to be equal by the hash table.  */
 567     return 0;
 568
 569   return memcmp (A->root.string + (A->len - B->len),
 570                  B->root.string, B->len) == 0;
 571 }
 572
 573 /* This is a helper function for _bfd_merge_sections.  It attempts to
 574    merge strings matching suffixes of longer strings.  */
 575 static void
 576 merge_strings (struct sec_merge_info *sinfo)
 577 {
 578   struct sec_merge_hash_entry **array, **a, *e;
 579   struct sec_merge_sec_info *secinfo;
 580   bfd_size_type size, amt;
 581   unsigned int alignment = 0;
 582
 583   /* Now sort the strings */
 584   amt = sinfo->htab->size * sizeof (struct sec_merge_hash_entry *);
 585   array = bfd_malloc (amt);
 586   if (array == NULL)
 587     goto alloc_failure;
 588
 589   for (e = sinfo->htab->first, a = array; e; e = e->next)
 590     if (e->alignment)
 591       {
 592         *a++ = e;
 593         /* Adjust the length to not include the zero terminator.  */
 594         e->len -= sinfo->htab->entsize;
 595         if (alignment != e->alignment)
 596           {
 597             if (alignment == 0)
 598               alignment = e->alignment;
 599             else
 600               alignment = (unsigned) -1;
 601           }
 602       }
 603
 604   sinfo->htab->size = a - array;
 605   if (sinfo->htab->size != 0)
 606     {
 607       qsort (array, (size_t) sinfo->htab->size,
 608              sizeof (struct sec_merge_hash_entry *),
 609              (alignment != (unsigned) -1 && alignment > sinfo->htab->entsize
 610               ? strrevcmp_align : strrevcmp));
 611
 612       /* Loop over the sorted array and merge suffixes */
 613       e = *--a;
 614       e->len += sinfo->htab->entsize;
 615       while (--a >= array)
 616         {
 617           struct sec_merge_hash_entry *cmp = *a;
 618
 619           cmp->len += sinfo->htab->entsize;
 620           if (e->alignment >= cmp->alignment
 621               && !((e->len - cmp->len) & (cmp->alignment - 1))
 622               && is_suffix (e, cmp))
 623             {
 624               cmp->u.suffix = e;
 625               cmp->alignment = 0;
 626             }
 627           else
 628             e = cmp;
 629         }
 630     }
 631
 632 alloc_failure:
 633   if (array)
 634     free (array);
 635
 636   /* Now assign positions to the strings we want to keep.  */
 637   size = 0;
 638   secinfo = sinfo->htab->first->secinfo;
 639   for (e = sinfo->htab->first; e; e = e->next)
 640     {
 641       if (e->secinfo != secinfo)
 642         {
 643           secinfo->sec->size = size;
 644           secinfo = e->secinfo;
 645         }
 646       if (e->alignment)
 647         {
 648           if (e->secinfo->first_str == NULL)
 649             {
 650               e->secinfo->first_str = e;
 651               size = 0;
 652             }
 653           size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
 654           e->u.index = size;
 655           size += e->len;
 656         }
 657     }
 658   secinfo->sec->size = size;
 659
 660   /* And now adjust the rest, removing them from the chain (but not hashtable)
 661      at the same time.  */
 662   for (a = &sinfo->htab->first, e = *a; e; e = e->next)
 663     if (e->alignment)
 664       a = &e->next;
 665     else
 666       {
 667         *a = e->next;
 668         if (e->len)
 669           {
 670             e->secinfo = e->u.suffix->secinfo;
 671             e->alignment = e->u.suffix->alignment;
 672             e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len);
 673           }
 674       }
 675 }
 676
 677 /* This function is called once after all SEC_MERGE sections are registered
 678    with _bfd_merge_section.  */
 679
 680 bfd_boolean
 681 _bfd_merge_sections (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_link_info *info,
 682                      void *xsinfo, void (*remove_hook) (bfd *, asection *))
 683 {
 684   struct sec_merge_info *sinfo;
 685
 686   for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
 687     {
 688       struct sec_merge_sec_info * secinfo;
 689
 690       if (! sinfo->chain)
 691         continue;
 692
 693       /* Move sinfo->chain to head of the chain, terminate it.  */
 694       secinfo = sinfo->chain;
 695       sinfo->chain = secinfo->next;
 696       secinfo->next = NULL;
 697
 698       /* Record the sections into the hash table.  */
 699       for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 700         if (secinfo->sec->flags & SEC_EXCLUDE)
 701           {
 702             *secinfo->psecinfo = NULL;
 703             if (remove_hook)
 704               (*remove_hook) (abfd, secinfo->sec);
 705           }
 706         else if (! record_section (sinfo, secinfo))
 707           break;
 708
 709       if (secinfo)
 710         continue;
 711
 712       if (sinfo->htab->first == NULL)
 713         continue;
 714
 715       if (sinfo->htab->strings)
 716         merge_strings (sinfo);
 717       else
 718         {
 719           struct sec_merge_hash_entry *e;
 720           bfd_size_type size = 0;
 721
 722           /* Things are much simpler for non-strings.
 723              Just assign them slots in the section.  */
 724           secinfo = NULL;
 725           for (e = sinfo->htab->first; e; e = e->next)
 726             {
 727               if (e->secinfo->first_str == NULL)
 728                 {
 729                   if (secinfo)
 730                     secinfo->sec->size = size;
 731                   e->secinfo->first_str = e;
 732                   size = 0;
 733                 }
 734               size = (size + e->alignment - 1)
 735                      & ~((bfd_vma) e->alignment - 1);
 736               e->u.index = size;
 737               size += e->len;
 738               secinfo = e->secinfo;
 739             }
 740           secinfo->sec->size = size;
 741         }
 742
 743         /* Finally remove all input sections which have not made it into
 744            the hash table at all.  */
 745         for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 746           if (secinfo->first_str == NULL)
 747             _bfd_strip_section_from_output (info, secinfo->sec);
 748     }
 749
 750   return TRUE;
 751 }
 752
 753 /* Write out the merged section.  */
 754
 755 bfd_boolean
 756 _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
 757 {
 758   struct sec_merge_sec_info *secinfo;
 759   file_ptr pos;
 760
 761   secinfo = (struct sec_merge_sec_info *) psecinfo;
 762
 763   if (secinfo->first_str == NULL)
 764     return TRUE;
 765
 766   pos = sec->output_section->filepos + sec->output_offset;
 767   if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
 768     return FALSE;
 769
 770   if (! sec_merge_emit (output_bfd, secinfo->first_str))
 771     return FALSE;
 772
 773   return TRUE;
 774 }
 775
 776 /* Adjust an address in the SEC_MERGE section.  Given OFFSET within
 777    *PSEC, this returns the new offset in the adjusted SEC_MERGE
 778    section and writes the new section back into *PSEC.  */
 779
 780 bfd_vma
 781 _bfd_merged_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, asection **psec,
 782                             void *psecinfo, bfd_vma offset)
 783 {
 784   struct sec_merge_sec_info *secinfo;
 785   struct sec_merge_hash_entry *entry;
 786   unsigned char *p;
 787   asection *sec = *psec;
 788
 789   secinfo = (struct sec_merge_sec_info *) psecinfo;
 790
 791   if (offset >= sec->rawsize)
 792     {
 793       if (offset > sec->rawsize)
 794         {
 795           (*_bfd_error_handler)
 796             (_("%s: access beyond end of merged section (%ld)"),
 797              bfd_get_filename (sec->owner), (long) offset);
 798         }
 799       return secinfo->first_str ? sec->size : 0;
 800     }
 801
 802   if (secinfo->htab->strings)
 803     {
 804       if (sec->entsize == 1)
 805         {
 806           p = secinfo->contents + offset - 1;
 807           while (p >= secinfo->contents && *p)
 808             --p;
 809           ++p;
 810         }
 811       else
 812         {
 813           p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 814           p -= sec->entsize;
 815           while (p >= secinfo->contents)
 816             {
 817               unsigned int i;
 818
 819               for (i = 0; i < sec->entsize; ++i)
 820                 if (p[i] != '\0')
 821                   break;
 822               if (i == sec->entsize)
 823                 break;
 824               p -= sec->entsize;
 825             }
 826           p += sec->entsize;
 827         }
 828     }
 829   else
 830     {
 831       p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
 832     }
 833   entry = sec_merge_hash_lookup (secinfo->htab, (char *) p, 0, FALSE);
 834   if (!entry)
 835     {
 836       if (! secinfo->htab->strings)
 837         abort ();
 838       /* This should only happen if somebody points into the padding
 839          after a NUL character but before next entity.  */
 840       if (*p)
 841         abort ();
 842       if (! secinfo->htab->first)
 843         abort ();
 844       entry = secinfo->htab->first;
 845       p = (secinfo->contents + (offset / sec->entsize + 1) * sec->entsize
 846            - entry->len);
 847     }
 848
 849   *psec = entry->secinfo->sec;
 850   return entry->u.index + (secinfo->contents + offset - p);
 851 }