bfd/hash.c

   1 /* hash.c -- hash table routines for BFD
   2    Copyright 1993, 1994, 1995, 1997, 1999, 2001, 2002, 2003, 2004, 2005
   3    Free Software Foundation, Inc.
   4    Written by Steve Chamberlain <sac@cygnus.com>
   5
   6    This file is part of BFD, the Binary File Descriptor library.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  21
  22 #include "bfd.h"
  23 #include "sysdep.h"
  24 #include "libbfd.h"
  25 #include "objalloc.h"
  26 #include "libiberty.h"
  27
  28 /*
  29 SECTION
  30         Hash Tables
  31
  32 @cindex Hash tables
  33         BFD provides a simple set of hash table functions.  Routines
  34         are provided to initialize a hash table, to free a hash table,
  35         to look up a string in a hash table and optionally create an
  36         entry for it, and to traverse a hash table.  There is
  37         currently no routine to delete an string from a hash table.
  38
  39         The basic hash table does not permit any data to be stored
  40         with a string.  However, a hash table is designed to present a
  41         base class from which other types of hash tables may be
  42         derived.  These derived types may store additional information
  43         with the string.  Hash tables were implemented in this way,
  44         rather than simply providing a data pointer in a hash table
  45         entry, because they were designed for use by the linker back
  46         ends.  The linker may create thousands of hash table entries,
  47         and the overhead of allocating private data and storing and
  48         following pointers becomes noticeable.
  49
  50         The basic hash table code is in <<hash.c>>.
  51
  52 @menu
  53 @* Creating and Freeing a Hash Table::
  54 @* Looking Up or Entering a String::
  55 @* Traversing a Hash Table::
  56 @* Deriving a New Hash Table Type::
  57 @end menu
  58
  59 INODE
  60 Creating and Freeing a Hash Table, Looking Up or Entering a String, Hash Tables, Hash Tables
  61 SUBSECTION
  62         Creating and freeing a hash table
  63
  64 @findex bfd_hash_table_init
  65 @findex bfd_hash_table_init_n
  66         To create a hash table, create an instance of a <<struct
  67         bfd_hash_table>> (defined in <<bfd.h>>) and call
  68         <<bfd_hash_table_init>> (if you know approximately how many
  69         entries you will need, the function <<bfd_hash_table_init_n>>,
  70         which takes a @var{size} argument, may be used).
  71         <<bfd_hash_table_init>> returns <<FALSE>> if some sort of
  72         error occurs.
  73
  74 @findex bfd_hash_newfunc
  75         The function <<bfd_hash_table_init>> take as an argument a
  76         function to use to create new entries.  For a basic hash
  77         table, use the function <<bfd_hash_newfunc>>.  @xref{Deriving
  78         a New Hash Table Type}, for why you would want to use a
  79         different value for this argument.
  80
  81 @findex bfd_hash_allocate
  82         <<bfd_hash_table_init>> will create an objalloc which will be
  83         used to allocate new entries.  You may allocate memory on this
  84         objalloc using <<bfd_hash_allocate>>.
  85
  86 @findex bfd_hash_table_free
  87         Use <<bfd_hash_table_free>> to free up all the memory that has
  88         been allocated for a hash table.  This will not free up the
  89         <<struct bfd_hash_table>> itself, which you must provide.
  90
  91 @findex bfd_hash_set_default_size
  92         Use <<bfd_hash_set_default_size>> to set the default size of
  93         hash table to use.
  94
  95 INODE
  96 Looking Up or Entering a String, Traversing a Hash Table, Creating and Freeing a Hash Table, Hash Tables
  97 SUBSECTION
  98         Looking up or entering a string
  99
 100 @findex bfd_hash_lookup
 101         The function <<bfd_hash_lookup>> is used both to look up a
 102         string in the hash table and to create a new entry.
 103
 104         If the @var{create} argument is <<FALSE>>, <<bfd_hash_lookup>>
 105         will look up a string.  If the string is found, it will
 106         returns a pointer to a <<struct bfd_hash_entry>>.  If the
 107         string is not found in the table <<bfd_hash_lookup>> will
 108         return <<NULL>>.  You should not modify any of the fields in
 109         the returns <<struct bfd_hash_entry>>.
 110
 111         If the @var{create} argument is <<TRUE>>, the string will be
 112         entered into the hash table if it is not already there.
 113         Either way a pointer to a <<struct bfd_hash_entry>> will be
 114         returned, either to the existing structure or to a newly
 115         created one.  In this case, a <<NULL>> return means that an
 116         error occurred.
 117
 118         If the @var{create} argument is <<TRUE>>, and a new entry is
 119         created, the @var{copy} argument is used to decide whether to
 120         copy the string onto the hash table objalloc or not.  If
 121         @var{copy} is passed as <<FALSE>>, you must be careful not to
 122         deallocate or modify the string as long as the hash table
 123         exists.
 124
 125 INODE
 126 Traversing a Hash Table, Deriving a New Hash Table Type, Looking Up or Entering a String, Hash Tables
 127 SUBSECTION
 128         Traversing a hash table
 129
 130 @findex bfd_hash_traverse
 131         The function <<bfd_hash_traverse>> may be used to traverse a
 132         hash table, calling a function on each element.  The traversal
 133         is done in a random order.
 134
 135         <<bfd_hash_traverse>> takes as arguments a function and a
 136         generic <<void *>> pointer.  The function is called with a
 137         hash table entry (a <<struct bfd_hash_entry *>>) and the
 138         generic pointer passed to <<bfd_hash_traverse>>.  The function
 139         must return a <<boolean>> value, which indicates whether to
 140         continue traversing the hash table.  If the function returns
 141         <<FALSE>>, <<bfd_hash_traverse>> will stop the traversal and
 142         return immediately.
 143
 144 INODE
 145 Deriving a New Hash Table Type, , Traversing a Hash Table, Hash Tables
 146 SUBSECTION
 147         Deriving a new hash table type
 148
 149         Many uses of hash tables want to store additional information
 150         which each entry in the hash table.  Some also find it
 151         convenient to store additional information with the hash table
 152         itself.  This may be done using a derived hash table.
 153
 154         Since C is not an object oriented language, creating a derived
 155         hash table requires sticking together some boilerplate
 156         routines with a few differences specific to the type of hash
 157         table you want to create.
 158
 159         An example of a derived hash table is the linker hash table.
 160         The structures for this are defined in <<bfdlink.h>>.  The
 161         functions are in <<linker.c>>.
 162
 163         You may also derive a hash table from an already derived hash
 164         table.  For example, the a.out linker backend code uses a hash
 165         table derived from the linker hash table.
 166
 167 @menu
 168 @* Define the Derived Structures::
 169 @* Write the Derived Creation Routine::
 170 @* Write Other Derived Routines::
 171 @end menu
 172
 173 INODE
 174 Define the Derived Structures, Write the Derived Creation Routine, Deriving a New Hash Table Type, Deriving a New Hash Table Type
 175 SUBSUBSECTION
 176         Define the derived structures
 177
 178         You must define a structure for an entry in the hash table,
 179         and a structure for the hash table itself.
 180
 181         The first field in the structure for an entry in the hash
 182         table must be of the type used for an entry in the hash table
 183         you are deriving from.  If you are deriving from a basic hash
 184         table this is <<struct bfd_hash_entry>>, which is defined in
 185         <<bfd.h>>.  The first field in the structure for the hash
 186         table itself must be of the type of the hash table you are
 187         deriving from itself.  If you are deriving from a basic hash
 188         table, this is <<struct bfd_hash_table>>.
 189
 190         For example, the linker hash table defines <<struct
 191         bfd_link_hash_entry>> (in <<bfdlink.h>>).  The first field,
 192         <<root>>, is of type <<struct bfd_hash_entry>>.  Similarly,
 193         the first field in <<struct bfd_link_hash_table>>, <<table>>,
 194         is of type <<struct bfd_hash_table>>.
 195
 196 INODE
 197 Write the Derived Creation Routine, Write Other Derived Routines, Define the Derived Structures, Deriving a New Hash Table Type
 198 SUBSUBSECTION
 199         Write the derived creation routine
 200
 201         You must write a routine which will create and initialize an
 202         entry in the hash table.  This routine is passed as the
 203         function argument to <<bfd_hash_table_init>>.
 204
 205         In order to permit other hash tables to be derived from the
 206         hash table you are creating, this routine must be written in a
 207         standard way.
 208
 209         The first argument to the creation routine is a pointer to a
 210         hash table entry.  This may be <<NULL>>, in which case the
 211         routine should allocate the right amount of space.  Otherwise
 212         the space has already been allocated by a hash table type
 213         derived from this one.
 214
 215         After allocating space, the creation routine must call the
 216         creation routine of the hash table type it is derived from,
 217         passing in a pointer to the space it just allocated.  This
 218         will initialize any fields used by the base hash table.
 219
 220         Finally the creation routine must initialize any local fields
 221         for the new hash table type.
 222
 223         Here is a boilerplate example of a creation routine.
 224         @var{function_name} is the name of the routine.
 225         @var{entry_type} is the type of an entry in the hash table you
 226         are creating.  @var{base_newfunc} is the name of the creation
 227         routine of the hash table type your hash table is derived
 228         from.
 229
 230 EXAMPLE
 231
 232 .struct bfd_hash_entry *
 233 .@var{function_name} (struct bfd_hash_entry *entry,
 234 .                     struct bfd_hash_table *table,
 235 .                     const char *string)
 236 .{
 237 .  struct @var{entry_type} *ret = (@var{entry_type} *) entry;
 238 .
 239 . {* Allocate the structure if it has not already been allocated by a
 240 .    derived class.  *}
 241 .  if (ret == NULL)
 242 .    {
 243 .      ret = bfd_hash_allocate (table, sizeof (* ret));
 244 .      if (ret == NULL)
 245 .        return NULL;
 246 .    }
 247 .
 248 . {* Call the allocation method of the base class.  *}
 249 .  ret = ((@var{entry_type} *)
 250 .        @var{base_newfunc} ((struct bfd_hash_entry *) ret, table, string));
 251 .
 252 . {* Initialize the local fields here.  *}
 253 .
 254 .  return (struct bfd_hash_entry *) ret;
 255 .}
 256
 257 DESCRIPTION
 258         The creation routine for the linker hash table, which is in
 259         <<linker.c>>, looks just like this example.
 260         @var{function_name} is <<_bfd_link_hash_newfunc>>.
 261         @var{entry_type} is <<struct bfd_link_hash_entry>>.
 262         @var{base_newfunc} is <<bfd_hash_newfunc>>, the creation
 263         routine for a basic hash table.
 264
 265         <<_bfd_link_hash_newfunc>> also initializes the local fields
 266         in a linker hash table entry: <<type>>, <<written>> and
 267         <<next>>.
 268
 269 INODE
 270 Write Other Derived Routines, , Write the Derived Creation Routine, Deriving a New Hash Table Type
 271 SUBSUBSECTION
 272         Write other derived routines
 273
 274         You will want to write other routines for your new hash table,
 275         as well.
 276
 277         You will want an initialization routine which calls the
 278         initialization routine of the hash table you are deriving from
 279         and initializes any other local fields.  For the linker hash
 280         table, this is <<_bfd_link_hash_table_init>> in <<linker.c>>.
 281
 282         You will want a lookup routine which calls the lookup routine
 283         of the hash table you are deriving from and casts the result.
 284         The linker hash table uses <<bfd_link_hash_lookup>> in
 285         <<linker.c>> (this actually takes an additional argument which
 286         it uses to decide how to return the looked up value).
 287
 288         You may want a traversal routine.  This should just call the
 289         traversal routine of the hash table you are deriving from with
 290         appropriate casts.  The linker hash table uses
 291         <<bfd_link_hash_traverse>> in <<linker.c>>.
 292
 293         These routines may simply be defined as macros.  For example,
 294         the a.out backend linker hash table, which is derived from the
 295         linker hash table, uses macros for the lookup and traversal
 296         routines.  These are <<aout_link_hash_lookup>> and
 297         <<aout_link_hash_traverse>> in aoutx.h.
 298 */
 299
 300 /* The default number of entries to use when creating a hash table.  */
 301 #define DEFAULT_SIZE 4051
 302 static size_t bfd_default_hash_table_size = DEFAULT_SIZE;
 303
 304 /* Create a new hash table, given a number of entries.  */
 305
 306 bfd_boolean
 307 bfd_hash_table_init_n (struct bfd_hash_table *table,
 308                        struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
 309                                                           struct bfd_hash_table *,
 310                                                           const char *),
 311                        unsigned int size)
 312 {
 313   unsigned int alloc;
 314
 315   alloc = size * sizeof (struct bfd_hash_entry *);
 316
 317   table->memory = (void *) objalloc_create ();
 318   if (table->memory == NULL)
 319     {
 320       bfd_set_error (bfd_error_no_memory);
 321       return FALSE;
 322     }
 323   table->table = objalloc_alloc ((struct objalloc *) table->memory, alloc);
 324   if (table->table == NULL)
 325     {
 326       bfd_set_error (bfd_error_no_memory);
 327       return FALSE;
 328     }
 329   memset ((void *) table->table, 0, alloc);
 330   table->size = size;
 331   table->newfunc = newfunc;
 332   return TRUE;
 333 }
 334
 335 /* Create a new hash table with the default number of entries.  */
 336
 337 bfd_boolean
 338 bfd_hash_table_init (struct bfd_hash_table *table,
 339                      struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
 340                                                         struct bfd_hash_table *,
 341                                                         const char *))
 342 {
 343   return bfd_hash_table_init_n (table, newfunc, bfd_default_hash_table_size);
 344 }
 345
 346 /* Free a hash table.  */
 347
 348 void
 349 bfd_hash_table_free (struct bfd_hash_table *table)
 350 {
 351   objalloc_free (table->memory);
 352   table->memory = NULL;
 353 }
 354
 355 /* Look up a string in a hash table.  */
 356
 357 struct bfd_hash_entry *
 358 bfd_hash_lookup (struct bfd_hash_table *table,
 359                  const char *string,
 360                  bfd_boolean create,
 361                  bfd_boolean copy)
 362 {
 363   const unsigned char *s;
 364   unsigned long hash;
 365   unsigned int c;
 366   struct bfd_hash_entry *hashp;
 367   unsigned int len;
 368   unsigned int index;
 369
 370   hash = 0;
 371   len = 0;
 372   s = (const unsigned char *) string;
 373   while ((c = *s++) != '\0')
 374     {
 375       hash += c + (c << 17);
 376       hash ^= hash >> 2;
 377     }
 378   len = (s - (const unsigned char *) string) - 1;
 379   hash += len + (len << 17);
 380   hash ^= hash >> 2;
 381
 382   index = hash % table->size;
 383   for (hashp = table->table[index];
 384        hashp != NULL;
 385        hashp = hashp->next)
 386     {
 387       if (hashp->hash == hash
 388           && strcmp (hashp->string, string) == 0)
 389         return hashp;
 390     }
 391
 392   if (! create)
 393     return NULL;
 394
 395   hashp = (*table->newfunc) (NULL, table, string);
 396   if (hashp == NULL)
 397     return NULL;
 398   if (copy)
 399     {
 400       char *new;
 401
 402       new = objalloc_alloc ((struct objalloc *) table->memory, len + 1);
 403       if (!new)
 404         {
 405           bfd_set_error (bfd_error_no_memory);
 406           return NULL;
 407         }
 408       memcpy (new, string, len + 1);
 409       string = new;
 410     }
 411   hashp->string = string;
 412   hashp->hash = hash;
 413   hashp->next = table->table[index];
 414   table->table[index] = hashp;
 415
 416   return hashp;
 417 }
 418
 419 /* Replace an entry in a hash table.  */
 420
 421 void
 422 bfd_hash_replace (struct bfd_hash_table *table,
 423                   struct bfd_hash_entry *old,
 424                   struct bfd_hash_entry *nw)
 425 {
 426   unsigned int index;
 427   struct bfd_hash_entry **pph;
 428
 429   index = old->hash % table->size;
 430   for (pph = &table->table[index];
 431        (*pph) != NULL;
 432        pph = &(*pph)->next)
 433     {
 434       if (*pph == old)
 435         {
 436           *pph = nw;
 437           return;
 438         }
 439     }
 440
 441   abort ();
 442 }
 443
 444 /* Allocate space in a hash table.  */
 445
 446 void *
 447 bfd_hash_allocate (struct bfd_hash_table *table,
 448                    unsigned int size)
 449 {
 450   void * ret;
 451
 452   ret = objalloc_alloc ((struct objalloc *) table->memory, size);
 453   if (ret == NULL && size != 0)
 454     bfd_set_error (bfd_error_no_memory);
 455   return ret;
 456 }
 457
 458 /* Base method for creating a new hash table entry.  */
 459
 460 struct bfd_hash_entry *
 461 bfd_hash_newfunc (struct bfd_hash_entry *entry,
 462                   struct bfd_hash_table *table,
 463                   const char *string ATTRIBUTE_UNUSED)
 464 {
 465   if (entry == NULL)
 466     entry = bfd_hash_allocate (table, sizeof (* entry));
 467   return entry;
 468 }
 469
 470 /* Traverse a hash table.  */
 471
 472 void
 473 bfd_hash_traverse (struct bfd_hash_table *table,
 474                    bfd_boolean (*func) (struct bfd_hash_entry *, void *),
 475                    void * info)
 476 {
 477   unsigned int i;
 478
 479   for (i = 0; i < table->size; i++)
 480     {
 481       struct bfd_hash_entry *p;
 482
 483       for (p = table->table[i]; p != NULL; p = p->next)
 484         if (! (*func) (p, info))
 485           return;
 486     }
 487 }
 488 \f
 489 void
 490 bfd_hash_set_default_size (bfd_size_type hash_size)
 491 {
 492   /* Extend this prime list if you want more granularity of hash table size.  */
 493   static const bfd_size_type hash_size_primes[] =
 494     {
 495       1021, 4051, 8599, 16699
 496     };
 497   size_t index;
 498
 499   /* Work out best prime number near the hash_size.  */
 500   for (index = 0; index < ARRAY_SIZE (hash_size_primes) - 1; ++index)
 501     if (hash_size <= hash_size_primes[index])
 502       break;
 503
 504   bfd_default_hash_table_size = hash_size_primes[index];
 505 }
 506 \f
 507 /* A few different object file formats (a.out, COFF, ELF) use a string
 508    table.  These functions support adding strings to a string table,
 509    returning the byte offset, and writing out the table.
 510
 511    Possible improvements:
 512    + look for strings matching trailing substrings of other strings
 513    + better data structures?  balanced trees?
 514    + look at reducing memory use elsewhere -- maybe if we didn't have
 515      to construct the entire symbol table at once, we could get by
 516      with smaller amounts of VM?  (What effect does that have on the
 517      string table reductions?)  */
 518
 519 /* An entry in the strtab hash table.  */
 520
 521 struct strtab_hash_entry
 522 {
 523   struct bfd_hash_entry root;
 524   /* Index in string table.  */
 525   bfd_size_type index;
 526   /* Next string in strtab.  */
 527   struct strtab_hash_entry *next;
 528 };
 529
 530 /* The strtab hash table.  */
 531
 532 struct bfd_strtab_hash
 533 {
 534   struct bfd_hash_table table;
 535   /* Size of strtab--also next available index.  */
 536   bfd_size_type size;
 537   /* First string in strtab.  */
 538   struct strtab_hash_entry *first;
 539   /* Last string in strtab.  */
 540   struct strtab_hash_entry *last;
 541   /* Whether to precede strings with a two byte length, as in the
 542      XCOFF .debug section.  */
 543   bfd_boolean xcoff;
 544 };
 545
 546 /* Routine to create an entry in a strtab.  */
 547
 548 static struct bfd_hash_entry *
 549 strtab_hash_newfunc (struct bfd_hash_entry *entry,
 550                      struct bfd_hash_table *table,
 551                      const char *string)
 552 {
 553   struct strtab_hash_entry *ret = (struct strtab_hash_entry *) entry;
 554
 555   /* Allocate the structure if it has not already been allocated by a
 556      subclass.  */
 557   if (ret == NULL)
 558     ret = bfd_hash_allocate (table, sizeof (* ret));
 559   if (ret == NULL)
 560     return NULL;
 561
 562   /* Call the allocation method of the superclass.  */
 563   ret = (struct strtab_hash_entry *)
 564          bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string);
 565
 566   if (ret)
 567     {
 568       /* Initialize the local fields.  */
 569       ret->index = (bfd_size_type) -1;
 570       ret->next = NULL;
 571     }
 572
 573   return (struct bfd_hash_entry *) ret;
 574 }
 575
 576 /* Look up an entry in an strtab.  */
 577
 578 #define strtab_hash_lookup(t, string, create, copy) \
 579   ((struct strtab_hash_entry *) \
 580    bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
 581
 582 /* Create a new strtab.  */
 583
 584 struct bfd_strtab_hash *
 585 _bfd_stringtab_init (void)
 586 {
 587   struct bfd_strtab_hash *table;
 588   bfd_size_type amt = sizeof (* table);
 589
 590   table = bfd_malloc (amt);
 591   if (table == NULL)
 592     return NULL;
 593
 594   if (! bfd_hash_table_init (& table->table, strtab_hash_newfunc))
 595     {
 596       free (table);
 597       return NULL;
 598     }
 599
 600   table->size = 0;
 601   table->first = NULL;
 602   table->last = NULL;
 603   table->xcoff = FALSE;
 604
 605   return table;
 606 }
 607
 608 /* Create a new strtab in which the strings are output in the format
 609    used in the XCOFF .debug section: a two byte length precedes each
 610    string.  */
 611
 612 struct bfd_strtab_hash *
 613 _bfd_xcoff_stringtab_init (void)
 614 {
 615   struct bfd_strtab_hash *ret;
 616
 617   ret = _bfd_stringtab_init ();
 618   if (ret != NULL)
 619     ret->xcoff = TRUE;
 620   return ret;
 621 }
 622
 623 /* Free a strtab.  */
 624
 625 void
 626 _bfd_stringtab_free (struct bfd_strtab_hash *table)
 627 {
 628   bfd_hash_table_free (&table->table);
 629   free (table);
 630 }
 631
 632 /* Get the index of a string in a strtab, adding it if it is not
 633    already present.  If HASH is FALSE, we don't really use the hash
 634    table, and we don't eliminate duplicate strings.  */
 635
 636 bfd_size_type
 637 _bfd_stringtab_add (struct bfd_strtab_hash *tab,
 638                     const char *str,
 639                     bfd_boolean hash,
 640                     bfd_boolean copy)
 641 {
 642   struct strtab_hash_entry *entry;
 643
 644   if (hash)
 645     {
 646       entry = strtab_hash_lookup (tab, str, TRUE, copy);
 647       if (entry == NULL)
 648         return (bfd_size_type) -1;
 649     }
 650   else
 651     {
 652       entry = bfd_hash_allocate (&tab->table, sizeof (* entry));
 653       if (entry == NULL)
 654         return (bfd_size_type) -1;
 655       if (! copy)
 656         entry->root.string = str;
 657       else
 658         {
 659           char *n;
 660
 661           n = bfd_hash_allocate (&tab->table, strlen (str) + 1);
 662           if (n == NULL)
 663             return (bfd_size_type) -1;
 664           entry->root.string = n;
 665         }
 666       entry->index = (bfd_size_type) -1;
 667       entry->next = NULL;
 668     }
 669
 670   if (entry->index == (bfd_size_type) -1)
 671     {
 672       entry->index = tab->size;
 673       tab->size += strlen (str) + 1;
 674       if (tab->xcoff)
 675         {
 676           entry->index += 2;
 677           tab->size += 2;
 678         }
 679       if (tab->first == NULL)
 680         tab->first = entry;
 681       else
 682         tab->last->next = entry;
 683       tab->last = entry;
 684     }
 685
 686   return entry->index;
 687 }
 688
 689 /* Get the number of bytes in a strtab.  */
 690
 691 bfd_size_type
 692 _bfd_stringtab_size (struct bfd_strtab_hash *tab)
 693 {
 694   return tab->size;
 695 }
 696
 697 /* Write out a strtab.  ABFD must already be at the right location in
 698    the file.  */
 699
 700 bfd_boolean
 701 _bfd_stringtab_emit (bfd *abfd, struct bfd_strtab_hash *tab)
 702 {
 703   bfd_boolean xcoff;
 704   struct strtab_hash_entry *entry;
 705
 706   xcoff = tab->xcoff;
 707
 708   for (entry = tab->first; entry != NULL; entry = entry->next)
 709     {
 710       const char *str;
 711       size_t len;
 712
 713       str = entry->root.string;
 714       len = strlen (str) + 1;
 715
 716       if (xcoff)
 717         {
 718           bfd_byte buf[2];
 719
 720           /* The output length includes the null byte.  */
 721           bfd_put_16 (abfd, (bfd_vma) len, buf);
 722           if (bfd_bwrite ((void *) buf, (bfd_size_type) 2, abfd) != 2)
 723             return FALSE;
 724         }
 725
 726       if (bfd_bwrite ((void *) str, (bfd_size_type) len, abfd) != len)
 727         return FALSE;
 728     }
 729
 730   return TRUE;
 731 }