bfd/merge.c

   1 /* SEC_MERGE support.
   2    Copyright 2001 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
  29 #include <ctype.h>
  30
  31 struct sec_merge_sec_info;
  32
  33 /* An entry in the section merge hash table.  */
  34
  35 struct sec_merge_hash_entry
  36 {
  37   struct bfd_hash_entry root;
  38   /* Length of this entry.  */
  39   unsigned int len;
  40   /* Start of this string needs to be aligned to
  41      alignment octets (not 1 << align).  */
  42   unsigned int alignment;
  43   union {
  44     /* Index within the merged section.  */
  45     bfd_size_type index;
  46     /* Entity size (if present in suffix hash tables).  */
  47     unsigned int entsize;
  48     /* Entry this is a suffix of (if alignment is 0).  */
  49     struct sec_merge_hash_entry *suffix;
  50   } u;
  51   /* Which section is it in.  */
  52   struct sec_merge_sec_info *secinfo;
  53   /* Next entity in the hash table.  */
  54   struct sec_merge_hash_entry *next;
  55 };
  56
  57 /* The section merge hash table.  */
  58
  59 struct sec_merge_hash
  60 {
  61   struct bfd_hash_table table;
  62   /* Next available index.  */
  63   bfd_size_type size;
  64   /* First entity in the SEC_MERGE sections of this type.  */
  65   struct sec_merge_hash_entry *first;
  66   /* Last entity in the SEC_MERGE sections of this type.  */
  67   struct sec_merge_hash_entry *last;
  68   /* Entity size.  */
  69   unsigned int entsize;
  70   /* Are entries fixed size or zero terminated strings?  */
  71   boolean strings;
  72 };
  73
  74 struct sec_merge_info
  75 {
  76   /* Chain of sec_merge_infos.  */
  77   struct sec_merge_info *next;
  78   /* Chain of sec_merge_sec_infos.  */
  79   struct sec_merge_sec_info *chain;
  80   /* A hash table used to hold section content.  */
  81   struct sec_merge_hash *htab;
  82 };
  83
  84 struct sec_merge_sec_info
  85 {
  86   /* Chain of sec_merge_sec_infos.  */
  87   struct sec_merge_sec_info *next;
  88   /* The corresponding section.  */
  89   asection *sec;
  90   /* Pointer to merge_info pointing to us.  */
  91   PTR *psecinfo;
  92   /* A hash table used to hold section content.  */
  93   struct sec_merge_hash *htab;
  94   /* First string in this section.  */
  95   struct sec_merge_hash_entry *first;
  96   /* Original section content.  */
  97   unsigned char contents[1];
  98 };
  99
 100 static struct bfd_hash_entry *sec_merge_hash_newfunc
 101   PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
 102 static struct sec_merge_hash_entry *sec_merge_hash_lookup
 103   PARAMS ((struct sec_merge_hash *, const char *, unsigned int, boolean));
 104 static struct sec_merge_hash *sec_merge_init
 105   PARAMS ((unsigned int, boolean));
 106 static struct sec_merge_hash_entry *sec_merge_add
 107   PARAMS ((struct sec_merge_hash *, const char *, unsigned int,
 108            struct sec_merge_sec_info *));
 109 static boolean sec_merge_emit
 110   PARAMS ((bfd *, struct sec_merge_hash_entry *));
 111 static int cmplengthentry PARAMS ((const PTR, const PTR));
 112 static int last4_eq PARAMS ((const PTR, const PTR));
 113 static int last_eq PARAMS ((const PTR, const PTR));
 114 static boolean record_section
 115   PARAMS ((struct sec_merge_info *, struct sec_merge_sec_info *));
 116 static void merge_strings PARAMS ((struct sec_merge_info *));
 117
 118 /* Routine to create an entry in a section merge hashtab.  */
 119
 120 static struct bfd_hash_entry *
 121 sec_merge_hash_newfunc (entry, table, string)
 122      struct bfd_hash_entry *entry;
 123      struct bfd_hash_table *table;
 124      const char *string;
 125 {
 126   struct sec_merge_hash_entry *ret = (struct sec_merge_hash_entry *) entry;
 127
 128   /* Allocate the structure if it has not already been allocated by a
 129      subclass.  */
 130   if (ret == (struct sec_merge_hash_entry *) NULL)
 131     ret = ((struct sec_merge_hash_entry *)
 132            bfd_hash_allocate (table, sizeof (struct sec_merge_hash_entry)));
 133   if (ret == (struct sec_merge_hash_entry *) NULL)
 134     return NULL;
 135
 136   /* Call the allocation method of the superclass.  */
 137   ret = ((struct sec_merge_hash_entry *)
 138          bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
 139
 140   if (ret)
 141     {
 142       /* Initialize the local fields.  */
 143       ret->u.suffix = NULL;
 144       ret->alignment = 0;
 145       ret->secinfo = NULL;
 146       ret->next = NULL;
 147     }
 148
 149   return (struct bfd_hash_entry *)ret;
 150 }
 151
 152 /* Look up an entry in a section merge hash table.  */
 153
 154 static struct sec_merge_hash_entry *
 155 sec_merge_hash_lookup (table, string, alignment, create)
 156      struct sec_merge_hash *table;
 157      const char *string;
 158      unsigned int alignment;
 159      boolean create;
 160 {
 161   register const unsigned char *s;
 162   register unsigned long hash;
 163   register unsigned int c;
 164   struct sec_merge_hash_entry *hashp;
 165   unsigned int len, i;
 166   unsigned int index;
 167
 168   hash = 0;
 169   len = 0;
 170   s = (const unsigned char *) string;
 171   if (table->strings)
 172     {
 173       if (table->entsize == 1)
 174         {
 175           while ((c = *s++) != '\0')
 176             {
 177               hash += c + (c << 17);
 178               hash ^= hash >> 2;
 179               ++len;
 180             }
 181           hash += len + (len << 17);
 182         }
 183       else
 184         {
 185           for (;;)
 186             {
 187               for (i = 0; i < table->entsize; ++i)
 188                 if (s[i] != '\0')
 189                   break;
 190               if (i == table->entsize)
 191                 break;
 192               for (i = 0; i < table->entsize; ++i)
 193                 {
 194                   c = *s++;
 195                   hash += c + (c << 17);
 196                   hash ^= hash >> 2;
 197                 }
 198               ++len;
 199             }
 200           hash += len + (len << 17);
 201           len *= table->entsize;
 202         }
 203       hash ^= hash >> 2;
 204       len += table->entsize;
 205     }
 206   else
 207     {
 208       for (i = 0; i < table->entsize; ++i)
 209         {
 210           c = *s++;
 211           hash += c + (c << 17);
 212           hash ^= hash >> 2;
 213         }
 214       len = table->entsize;
 215     }
 216
 217   index = hash % table->table.size;
 218   for (hashp = (struct sec_merge_hash_entry *) table->table.table[index];
 219        hashp != (struct sec_merge_hash_entry *) NULL;
 220        hashp = (struct sec_merge_hash_entry *) hashp->root.next)
 221     {
 222       if (hashp->root.hash == hash
 223           && len == hashp->len
 224           && memcmp (hashp->root.string, string, len) == 0)
 225         {
 226           /* If the string we found does not have at least the required
 227              alignment, we need to insert another copy.  */
 228           if (hashp->alignment < alignment)
 229             {
 230               /*  Mark the less aligned copy as deleted.  */
 231               hashp->len = 0;
 232               hashp->alignment = 0;
 233               break;
 234             }
 235           return hashp;
 236         }
 237     }
 238
 239   if (! create)
 240     return (struct sec_merge_hash_entry *) NULL;
 241
 242   hashp = (struct sec_merge_hash_entry *)
 243           sec_merge_hash_newfunc ((struct bfd_hash_entry *) NULL,
 244                                   (struct bfd_hash_table *) table, string);
 245   if (hashp == (struct sec_merge_hash_entry *) NULL)
 246     return (struct sec_merge_hash_entry *) NULL;
 247   hashp->root.string = string;
 248   hashp->root.hash = hash;
 249   hashp->len = len;
 250   hashp->alignment = alignment;
 251   hashp->root.next = table->table.table[index];
 252   table->table.table[index] = (struct bfd_hash_entry *) hashp;
 253
 254   return hashp;
 255 }
 256
 257 /* Create a new hash table.  */
 258
 259 static struct sec_merge_hash *
 260 sec_merge_init (entsize, strings)
 261      unsigned int entsize;
 262      boolean strings;
 263 {
 264   struct sec_merge_hash *table;
 265
 266   table = ((struct sec_merge_hash *)
 267            bfd_malloc (sizeof (struct sec_merge_hash)));
 268   if (table == NULL)
 269     return NULL;
 270
 271   if (! bfd_hash_table_init (&table->table, sec_merge_hash_newfunc))
 272     {
 273       free (table);
 274       return NULL;
 275     }
 276
 277   table->size = 0;
 278   table->first = NULL;
 279   table->last = NULL;
 280   table->entsize = entsize;
 281   table->strings = strings;
 282
 283   return table;
 284 }
 285
 286 /* Get the index of an entity in a hash table, adding it if it is not
 287    already present.  */
 288
 289 static struct sec_merge_hash_entry *
 290 sec_merge_add (tab, str, alignment, secinfo)
 291      struct sec_merge_hash *tab;
 292      const char *str;
 293      unsigned int alignment;
 294      struct sec_merge_sec_info *secinfo;
 295 {
 296   register struct sec_merge_hash_entry *entry;
 297
 298   entry = sec_merge_hash_lookup (tab, str, alignment, true);
 299   if (entry == NULL)
 300     return NULL;
 301
 302   if (entry->secinfo == NULL)
 303     {
 304       tab->size++;
 305       entry->secinfo = secinfo;
 306       if (tab->first == NULL)
 307         tab->first = entry;
 308       else
 309         tab->last->next = entry;
 310       tab->last = entry;
 311     }
 312
 313   return entry;
 314 }
 315
 316 static boolean
 317 sec_merge_emit (abfd, entry)
 318      register bfd *abfd;
 319      struct sec_merge_hash_entry *entry;
 320 {
 321   struct sec_merge_sec_info *secinfo = entry->secinfo;
 322   asection *sec = secinfo->sec;
 323   char *pad = "";
 324   bfd_size_type off = 0;
 325   int alignment_power = bfd_get_section_alignment (abfd, sec->output_section);
 326
 327   if (alignment_power)
 328     pad = bfd_zmalloc (1 << alignment_power);
 329
 330   for (; entry != NULL && entry->secinfo == secinfo; entry = entry->next)
 331     {
 332       register const char *str;
 333       register size_t len;
 334
 335       len = off & (entry->alignment - 1);
 336       if (len)
 337         {
 338           len = entry->alignment - len;
 339           if (bfd_write ((PTR) pad, 1, len, abfd) != len)
 340             break;
 341           off += len;
 342         }
 343
 344       str = entry->root.string;
 345       len = entry->len;
 346
 347       if (bfd_write ((PTR) str, 1, len, abfd) != len)
 348         break;
 349
 350       off += len;
 351     }
 352
 353   if (alignment_power)
 354     free (pad);
 355
 356   return entry == NULL || entry->secinfo != secinfo;
 357 }
 358
 359 /* This function is called for each input file from the add_symbols
 360    pass of the linker.  */
 361
 362 boolean
 363 _bfd_merge_section (abfd, psinfo, sec, psecinfo)
 364      bfd *abfd;
 365      PTR *psinfo;
 366      asection *sec;
 367      PTR *psecinfo;
 368 {
 369   struct sec_merge_info *sinfo;
 370   struct sec_merge_sec_info *secinfo;
 371   unsigned int align;
 372
 373   if (sec->_raw_size == 0
 374       || (sec->flags & SEC_EXCLUDE)
 375       || (sec->flags & SEC_MERGE) == 0
 376       || sec->entsize == 0)
 377     return true;
 378
 379   if ((sec->flags & SEC_RELOC) != 0)
 380     {
 381       /* We aren't prepared to handle relocations in merged sections.  */
 382       return true;
 383     }
 384
 385   if (sec->output_section != NULL
 386       && bfd_is_abs_section (sec->output_section))
 387     {
 388       /* The section is being discarded from the link, so we should
 389          just ignore it.  */
 390       return true;
 391     }
 392
 393   align = bfd_get_section_alignment (sec->owner, sec);
 394   if ((sec->entsize < (unsigned int)(1 << align)
 395        && ((sec->entsize & (sec->entsize - 1))
 396            || !(sec->flags & SEC_STRINGS)))
 397       || (sec->entsize > (unsigned int)(1 << align)
 398           && (sec->entsize & ((1 << align) - 1))))
 399     {
 400       /* Sanity check.  If string character size is smaller than
 401          alignment, then we require character size to be a power
 402          of 2, otherwise character size must be integer multiple
 403          of alignment.  For non-string constants, alignment must
 404          be smaller than or equal to entity size and entity size
 405          must be integer multiple of alignment.  */
 406       return true;
 407     }
 408
 409   for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next)
 410     if ((secinfo = sinfo->chain)
 411         && ! ((secinfo->sec->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS))
 412         && secinfo->sec->entsize == sec->entsize
 413         && ! strcmp (secinfo->sec->name, sec->name))
 414       break;
 415
 416   if (sinfo == NULL)
 417     {
 418       /* Initialize the information we need to keep track of.  */
 419       sinfo = (struct sec_merge_info *)
 420               bfd_alloc (abfd, sizeof (struct sec_merge_info));
 421       if (sinfo == NULL)
 422         goto error_return;
 423       sinfo->next = (struct sec_merge_info *) *psinfo;
 424       sinfo->chain = NULL;
 425       *psinfo = (PTR) sinfo;
 426       sinfo->htab =
 427         sec_merge_init (sec->entsize, (sec->flags & SEC_STRINGS));
 428       if (sinfo->htab == NULL)
 429         goto error_return;
 430     }
 431
 432   /* Read the section from abfd.  */
 433
 434   *psecinfo = bfd_alloc (abfd, sizeof (struct sec_merge_sec_info)
 435                                + sec->_raw_size - 1);
 436   if (*psecinfo == NULL)
 437     goto error_return;
 438
 439   secinfo = (struct sec_merge_sec_info *)*psecinfo;
 440   if (sinfo->chain)
 441     {
 442       secinfo->next = sinfo->chain->next;
 443       sinfo->chain->next = secinfo;
 444     }
 445   else
 446     secinfo->next = secinfo;
 447   sinfo->chain = secinfo;
 448   secinfo->sec = sec;
 449   secinfo->psecinfo = psecinfo;
 450   secinfo->htab = sinfo->htab;
 451   secinfo->first = NULL;
 452
 453   if (! bfd_get_section_contents (sec->owner, sec, secinfo->contents, 0,
 454                                   sec->_raw_size))
 455     goto error_return;
 456
 457   return true;
 458
 459  error_return:
 460   *psecinfo = NULL;
 461   return false;
 462 }
 463
 464 /* Compare two sec_merge_hash_entry structures.  This is called via qsort.  */
 465
 466 static int
 467 cmplengthentry (a, b)
 468      const PTR a;
 469      const PTR b;
 470 {
 471   struct sec_merge_hash_entry * A = *(struct sec_merge_hash_entry **) a;
 472   struct sec_merge_hash_entry * B = *(struct sec_merge_hash_entry **) b;
 473
 474   if (A->len < B->len)
 475     return 1;
 476   else if (A->len > B->len)
 477     return -1;
 478
 479   return memcmp (A->root.string, B->root.string, A->len);
 480 }
 481
 482 static int
 483 last4_eq (a, b)
 484      const PTR a;
 485      const PTR b;
 486 {
 487   struct sec_merge_hash_entry * A = (struct sec_merge_hash_entry *) a;
 488   struct sec_merge_hash_entry * B = (struct sec_merge_hash_entry *) b;
 489
 490   if (memcmp (A->root.string + A->len - 5 * A->u.entsize,
 491               B->root.string + B->len - 5 * A->u.entsize,
 492               4 * A->u.entsize) != 0)
 493     /* This was a hashtable collision.  */
 494     return 0;
 495
 496   if (A->len <= B->len)
 497     /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
 498        not to be equal by the hash table.  */
 499     return 0;
 500
 501   if (A->alignment < B->alignment
 502       || ((A->len - B->len) & (B->alignment - 1)))
 503     /* The suffix is not sufficiently aligned.  */
 504     return 0;
 505
 506   return memcmp (A->root.string + (A->len - B->len),
 507                  B->root.string, B->len - 5 * A->u.entsize) == 0;
 508 }
 509
 510 static int
 511 last_eq (a, b)
 512      const PTR a;
 513      const PTR b;
 514 {
 515   struct sec_merge_hash_entry * A = (struct sec_merge_hash_entry *) a;
 516   struct sec_merge_hash_entry * B = (struct sec_merge_hash_entry *) b;
 517
 518   if (B->len >= 5 * A->u.entsize)
 519     /* Longer strings are just pushed into the hash table,
 520        they'll be used when looking up for very short strings.  */
 521     return 0;
 522
 523   if (memcmp (A->root.string + A->len - 2 * A->u.entsize,
 524               B->root.string + B->len - 2 * A->u.entsize,
 525               A->u.entsize) != 0)
 526     /* This was a hashtable collision.  */
 527     return 0;
 528
 529   if (A->len <= B->len)
 530     /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
 531        not to be equal by the hash table.  */
 532     return 0;
 533
 534   if (A->alignment < B->alignment
 535       || ((A->len - B->len) & (B->alignment - 1)))
 536     /* The suffix is not sufficiently aligned.  */
 537     return 0;
 538
 539   return memcmp (A->root.string + (A->len - B->len),
 540                  B->root.string, B->len - 2 * A->u.entsize) == 0;
 541 }
 542
 543 /* Record one section into the hash table.  */
 544 static boolean
 545 record_section (sinfo, secinfo)
 546      struct sec_merge_info *sinfo;
 547      struct sec_merge_sec_info *secinfo;
 548 {
 549   asection *sec = secinfo->sec;
 550   struct sec_merge_hash_entry *entry;
 551   boolean nul;
 552   unsigned char *p, *end;
 553   bfd_vma mask, eltalign;
 554   unsigned int align, i;
 555
 556   align = bfd_get_section_alignment (sec->owner, sec);
 557   end = secinfo->contents + sec->_raw_size;
 558   nul = false;
 559   mask = ((bfd_vma)1 << align) - 1;
 560   if (sec->flags & SEC_STRINGS)
 561     {
 562       for (p = secinfo->contents; p < end;)
 563         {
 564           eltalign = p - secinfo->contents;
 565           eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1;
 566           if (!eltalign || eltalign > mask)
 567             eltalign = mask + 1;
 568           entry = sec_merge_add (sinfo->htab, p, eltalign, secinfo);
 569           if (! entry)
 570             goto error_return;
 571           p += entry->len;
 572           if (sec->entsize == 1)
 573             {
 574               while (p < end && *p == 0)
 575                 {
 576                   if (!nul && !((p - secinfo->contents) & mask))
 577                     {
 578                       nul = true;
 579                       entry = sec_merge_add (sinfo->htab, "", mask + 1,
 580                                              secinfo);
 581                       if (! entry)
 582                         goto error_return;
 583                     }
 584                   p++;
 585                 }
 586             }
 587           else
 588             {
 589               while (p < end)
 590                 {
 591                   for (i = 0; i < sec->entsize; i++)
 592                     if (p[i] != '\0')
 593                       break;
 594                   if (i != sec->entsize)
 595                     break;
 596                   if (!nul && !((p - secinfo->contents) & mask))
 597                     {
 598                       nul = true;
 599                       entry = sec_merge_add (sinfo->htab, p, mask + 1,
 600                                              secinfo);
 601                       if (! entry)
 602                         goto error_return;
 603                     }
 604                   p += sec->entsize;
 605                 }
 606             }
 607         }
 608     }
 609   else
 610     {
 611       for (p = secinfo->contents; p < end; p += sec->entsize)
 612         {
 613           entry = sec_merge_add (sinfo->htab, p, 1, secinfo);
 614           if (! entry)
 615             goto error_return;
 616         }
 617     }
 618
 619   return true;
 620
 621 error_return:
 622   for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 623     *secinfo->psecinfo = NULL;
 624   return false;
 625 }
 626
 627 /* This is a helper function for _bfd_merge_sections.  It attempts to
 628    merge strings matching suffixes of longer strings.  */
 629 static void
 630 merge_strings (sinfo)
 631      struct sec_merge_info *sinfo;
 632 {
 633   struct sec_merge_hash_entry **array, **a, **end, *e;
 634   struct sec_merge_sec_info *secinfo;
 635   htab_t lasttab = NULL, last4tab = NULL;
 636   bfd_size_type size;
 637
 638   /* Now sort the strings by length, longest first.  */
 639   array = (struct sec_merge_hash_entry **)
 640           malloc (sinfo->htab->size
 641                   * sizeof (struct sec_merge_hash_entry *));
 642   if (array == NULL)
 643     goto alloc_failure;
 644
 645   for (e = sinfo->htab->first, a = array; e; e = e->next)
 646     if (e->alignment)
 647       *a++ = e;
 648
 649   sinfo->htab->size = a - array;
 650
 651   qsort (array, sinfo->htab->size, sizeof (struct sec_merge_hash_entry *),
 652          cmplengthentry);
 653
 654   last4tab = htab_create (sinfo->htab->size * 4, NULL, last4_eq, NULL);
 655   lasttab = htab_create (sinfo->htab->size * 4, NULL, last_eq, NULL);
 656   if (lasttab == NULL || last4tab == NULL)
 657     goto alloc_failure;
 658
 659   /* Now insert the strings into hash tables (strings with last 4 characters
 660      and strings with last character equal), look for longer strings which
 661      we're suffix of.  */
 662   for (a = array, end = array + sinfo->htab->size; a < end; a++)
 663     {
 664       register hashval_t hash;
 665       unsigned int c;
 666       unsigned int i;
 667       const unsigned char *s;
 668       PTR *p;
 669
 670       e = *a;
 671       e->u.entsize = sinfo->htab->entsize;
 672       if (e->len <= e->u.entsize)
 673         break;
 674       if (e->len > 4 * e->u.entsize)
 675         {
 676           s = e->root.string + e->len - e->u.entsize;
 677           hash = 0;
 678           for (i = 0; i < 4 * e->u.entsize; i++)
 679             {
 680               c = *--s;
 681               hash += c + (c << 17);
 682               hash ^= hash >> 2;
 683             }
 684           p = htab_find_slot_with_hash (last4tab, e, hash, INSERT);
 685           if (p == NULL)
 686             goto alloc_failure;
 687           if (*p)
 688             {
 689               struct sec_merge_hash_entry *ent;
 690
 691               ent = (struct sec_merge_hash_entry *) *p;
 692               e->u.suffix = ent;
 693               e->alignment = 0;
 694               continue;
 695             }
 696           else
 697             *p = (PTR) e;
 698         }
 699       s = e->root.string + e->len - e->u.entsize;
 700       hash = 0;
 701       for (i = 0; i < e->u.entsize; i++)
 702         {
 703           c = *--s;
 704           hash += c + (c << 17);
 705           hash ^= hash >> 2;
 706         }
 707       p = htab_find_slot_with_hash (lasttab, e, hash, INSERT);
 708       if (p == NULL)
 709         goto alloc_failure;
 710       if (*p)
 711         {
 712           struct sec_merge_hash_entry *ent;
 713
 714           ent = (struct sec_merge_hash_entry *) *p;
 715           e->u.suffix = ent;
 716           e->alignment = 0;
 717         }
 718       else
 719         *p = (PTR) e;
 720     }
 721
 722 alloc_failure:
 723   if (array)
 724     free (array);
 725   if (lasttab)
 726     htab_delete (lasttab);
 727   if (last4tab)
 728     htab_delete (last4tab);
 729
 730   /* Now assign positions to the strings we want to keep.  */
 731   size = 0;
 732   secinfo = sinfo->htab->first->secinfo;
 733   for (e = sinfo->htab->first; e; e = e->next)
 734     {
 735       if (e->secinfo != secinfo)
 736         {
 737           secinfo->sec->_cooked_size = size;
 738           secinfo = e->secinfo;
 739         }
 740       if (e->alignment)
 741         {
 742           if (e->secinfo->first == NULL)
 743             {
 744               e->secinfo->first = e;
 745               size = 0;
 746             }
 747           size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
 748           e->u.index = size;
 749           size += e->len;
 750         }
 751     }
 752   secinfo->sec->_cooked_size = size;
 753
 754   /* And now adjust the rest, removing them from the chain (but not hashtable)
 755      at the same time.  */
 756   for (a = &sinfo->htab->first, e = *a; e; e = e->next)
 757     if (e->alignment)
 758       a = &e->next;
 759     else
 760       {
 761         *a = e->next;
 762         if (e->len)
 763           {
 764             e->secinfo = e->u.suffix->secinfo;
 765             e->alignment = e->u.suffix->alignment;
 766             e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len);
 767           }
 768       }
 769 }
 770
 771 /* This function is called once after all SEC_MERGE sections are registered
 772    with _bfd_merge_section.  */
 773
 774 boolean
 775 _bfd_merge_sections (abfd, xsinfo)
 776      bfd *abfd ATTRIBUTE_UNUSED;
 777      PTR xsinfo;
 778 {
 779   struct sec_merge_info *sinfo;
 780
 781   for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
 782     {
 783       struct sec_merge_sec_info * secinfo;
 784
 785       if (! sinfo->chain)
 786         continue;
 787
 788       /* Move sinfo->chain to head of the chain, terminate it.  */
 789       secinfo = sinfo->chain;
 790       sinfo->chain = secinfo->next;
 791       secinfo->next = NULL;
 792
 793       /* Record the sections into the hash table.  */
 794       for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 795         if (secinfo->sec->flags & SEC_EXCLUDE)
 796           *secinfo->psecinfo = NULL;
 797         else if (! record_section (sinfo, secinfo))
 798           break;
 799
 800       if (secinfo)
 801         continue;
 802
 803       if (sinfo->htab->strings)
 804         merge_strings (sinfo);
 805       else
 806         {
 807           struct sec_merge_hash_entry *e;
 808           bfd_size_type size = 0;
 809
 810           /* Things are much simpler for non-strings.
 811              Just assign them slots in the section.  */
 812           secinfo = NULL;
 813           for (e = sinfo->htab->first; e; e = e->next)
 814             {
 815               if (e->secinfo->first == NULL)
 816                 {
 817                   if (secinfo)
 818                     secinfo->sec->_cooked_size = size;
 819                   e->secinfo->first = e;
 820                   size = 0;
 821                 }
 822               size = (size + e->alignment - 1)
 823                      & ~((bfd_vma) e->alignment - 1);
 824               e->u.index = size;
 825               size += e->len;
 826               secinfo = e->secinfo;
 827             }
 828           secinfo->sec->_cooked_size = size;
 829         }
 830
 831         /* Finally shrink all input sections which have not made it into
 832            the hash table at all.  */
 833         for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
 834           if (secinfo->first == NULL)
 835             {
 836               secinfo->sec->_cooked_size = 0;
 837               secinfo->sec->flags |= SEC_EXCLUDE;
 838             }
 839     }
 840
 841   return true;
 842 }
 843
 844 /* Write out the merged section.  */
 845
 846 boolean
 847 _bfd_write_merged_section (output_bfd, sec, psecinfo)
 848      bfd *output_bfd;
 849      asection *sec;
 850      PTR psecinfo;
 851 {
 852   struct sec_merge_sec_info *secinfo;
 853
 854   secinfo = (struct sec_merge_sec_info *) psecinfo;
 855
 856   if (!secinfo->first)
 857     return true;
 858
 859   if (bfd_seek (output_bfd,
 860                 (sec->output_section->filepos + sec->output_offset),
 861                 SEEK_SET) != 0)
 862     return false;
 863
 864   if (! sec_merge_emit (output_bfd, secinfo->first))
 865     return false;
 866
 867   return true;
 868 }
 869
 870 /* Adjust an address in the SEC_MERGE section.  Given OFFSET within
 871    *PSEC, this returns the new offset in the adjusted SEC_MERGE
 872    section and writes the new section back into *PSEC.  */
 873
 874 bfd_vma
 875 _bfd_merged_section_offset (output_bfd, psec, psecinfo, offset, addend)
 876      bfd *output_bfd ATTRIBUTE_UNUSED;
 877      asection **psec;
 878      PTR psecinfo;
 879      bfd_vma offset, addend;
 880 {
 881   struct sec_merge_sec_info *secinfo;
 882   struct sec_merge_hash_entry *entry;
 883   unsigned char *p;
 884   asection *sec = *psec;
 885
 886   secinfo = (struct sec_merge_sec_info *) psecinfo;
 887
 888   if (offset + addend >= sec->_raw_size)
 889     {
 890       if (offset + addend > sec->_raw_size)
 891         (*_bfd_error_handler) (_("%s: access beyond end of merged section (%ld + %ld)"),
 892                                bfd_get_filename (sec->owner), (long)offset,
 893                                (long) addend);
 894       return (secinfo->first ? sec->_cooked_size : 0);
 895     }
 896
 897   if (secinfo->htab->strings)
 898     {
 899       if (sec->entsize == 1)
 900         {
 901           p = secinfo->contents + offset + addend - 1;
 902           while (*p && p >= secinfo->contents)
 903             --p;
 904           ++p;
 905         }
 906       else
 907         {
 908           p = secinfo->contents
 909               + ((offset + addend) / sec->entsize) * sec->entsize;
 910           p -= sec->entsize;
 911           while (p >= secinfo->contents)
 912             {
 913               unsigned int i;
 914
 915               for (i = 0; i < sec->entsize; ++i)
 916                 if (p[i] != '\0')
 917                   break;
 918               if (i == sec->entsize)
 919                 break;
 920               p -= sec->entsize;
 921             }
 922           p += sec->entsize;
 923         }
 924     }
 925   else
 926     {
 927       p = secinfo->contents
 928           + ((offset + addend) / sec->entsize) * sec->entsize;
 929     }
 930   entry = sec_merge_hash_lookup (secinfo->htab, p, 0, false);
 931   if (!entry)
 932     {
 933       if (! secinfo->htab->strings)
 934         abort ();
 935       /* This should only happen if somebody points into the padding
 936          after a NUL character but before next entity.  */
 937       if (*p)
 938         abort ();
 939       if (! secinfo->htab->first)
 940         abort ();
 941       entry = secinfo->htab->first;
 942       p = secinfo->contents
 943           + ((offset + addend) / sec->entsize + 1) * sec->entsize
 944           - entry->len;
 945     }
 946
 947   *psec = entry->secinfo->sec;
 948   return entry->u.index + (secinfo->contents + offset - p);
 949 }