| 1 | /* hash.c -- hash table routines for BFD |
| 2 | Copyright 1993, 1994, 1995, 1997, 1999, 2001, 2002, 2003, 2004, 2005, |
| 3 | 2006, 2007, 2009, 2010, 2011, 2012 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 3 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, |
| 21 | MA 02110-1301, USA. */ |
| 22 | |
| 23 | #include "sysdep.h" |
| 24 | #include "bfd.h" |
| 25 | #include "libbfd.h" |
| 26 | #include "objalloc.h" |
| 27 | #include "libiberty.h" |
| 28 | |
| 29 | /* |
| 30 | SECTION |
| 31 | Hash Tables |
| 32 | |
| 33 | @cindex Hash tables |
| 34 | BFD provides a simple set of hash table functions. Routines |
| 35 | are provided to initialize a hash table, to free a hash table, |
| 36 | to look up a string in a hash table and optionally create an |
| 37 | entry for it, and to traverse a hash table. There is |
| 38 | currently no routine to delete an string from a hash table. |
| 39 | |
| 40 | The basic hash table does not permit any data to be stored |
| 41 | with a string. However, a hash table is designed to present a |
| 42 | base class from which other types of hash tables may be |
| 43 | derived. These derived types may store additional information |
| 44 | with the string. Hash tables were implemented in this way, |
| 45 | rather than simply providing a data pointer in a hash table |
| 46 | entry, because they were designed for use by the linker back |
| 47 | ends. The linker may create thousands of hash table entries, |
| 48 | and the overhead of allocating private data and storing and |
| 49 | following pointers becomes noticeable. |
| 50 | |
| 51 | The basic hash table code is in <<hash.c>>. |
| 52 | |
| 53 | @menu |
| 54 | @* Creating and Freeing a Hash Table:: |
| 55 | @* Looking Up or Entering a String:: |
| 56 | @* Traversing a Hash Table:: |
| 57 | @* Deriving a New Hash Table Type:: |
| 58 | @end menu |
| 59 | |
| 60 | INODE |
| 61 | Creating and Freeing a Hash Table, Looking Up or Entering a String, Hash Tables, Hash Tables |
| 62 | SUBSECTION |
| 63 | Creating and freeing a hash table |
| 64 | |
| 65 | @findex bfd_hash_table_init |
| 66 | @findex bfd_hash_table_init_n |
| 67 | To create a hash table, create an instance of a <<struct |
| 68 | bfd_hash_table>> (defined in <<bfd.h>>) and call |
| 69 | <<bfd_hash_table_init>> (if you know approximately how many |
| 70 | entries you will need, the function <<bfd_hash_table_init_n>>, |
| 71 | which takes a @var{size} argument, may be used). |
| 72 | <<bfd_hash_table_init>> returns <<FALSE>> if some sort of |
| 73 | error occurs. |
| 74 | |
| 75 | @findex bfd_hash_newfunc |
| 76 | The function <<bfd_hash_table_init>> take as an argument a |
| 77 | function to use to create new entries. For a basic hash |
| 78 | table, use the function <<bfd_hash_newfunc>>. @xref{Deriving |
| 79 | a New Hash Table Type}, for why you would want to use a |
| 80 | different value for this argument. |
| 81 | |
| 82 | @findex bfd_hash_allocate |
| 83 | <<bfd_hash_table_init>> will create an objalloc which will be |
| 84 | used to allocate new entries. You may allocate memory on this |
| 85 | objalloc using <<bfd_hash_allocate>>. |
| 86 | |
| 87 | @findex bfd_hash_table_free |
| 88 | Use <<bfd_hash_table_free>> to free up all the memory that has |
| 89 | been allocated for a hash table. This will not free up the |
| 90 | <<struct bfd_hash_table>> itself, which you must provide. |
| 91 | |
| 92 | @findex bfd_hash_set_default_size |
| 93 | Use <<bfd_hash_set_default_size>> to set the default size of |
| 94 | hash table to use. |
| 95 | |
| 96 | INODE |
| 97 | Looking Up or Entering a String, Traversing a Hash Table, Creating and Freeing a Hash Table, Hash Tables |
| 98 | SUBSECTION |
| 99 | Looking up or entering a string |
| 100 | |
| 101 | @findex bfd_hash_lookup |
| 102 | The function <<bfd_hash_lookup>> is used both to look up a |
| 103 | string in the hash table and to create a new entry. |
| 104 | |
| 105 | If the @var{create} argument is <<FALSE>>, <<bfd_hash_lookup>> |
| 106 | will look up a string. If the string is found, it will |
| 107 | returns a pointer to a <<struct bfd_hash_entry>>. If the |
| 108 | string is not found in the table <<bfd_hash_lookup>> will |
| 109 | return <<NULL>>. You should not modify any of the fields in |
| 110 | the returns <<struct bfd_hash_entry>>. |
| 111 | |
| 112 | If the @var{create} argument is <<TRUE>>, the string will be |
| 113 | entered into the hash table if it is not already there. |
| 114 | Either way a pointer to a <<struct bfd_hash_entry>> will be |
| 115 | returned, either to the existing structure or to a newly |
| 116 | created one. In this case, a <<NULL>> return means that an |
| 117 | error occurred. |
| 118 | |
| 119 | If the @var{create} argument is <<TRUE>>, and a new entry is |
| 120 | created, the @var{copy} argument is used to decide whether to |
| 121 | copy the string onto the hash table objalloc or not. If |
| 122 | @var{copy} is passed as <<FALSE>>, you must be careful not to |
| 123 | deallocate or modify the string as long as the hash table |
| 124 | exists. |
| 125 | |
| 126 | INODE |
| 127 | Traversing a Hash Table, Deriving a New Hash Table Type, Looking Up or Entering a String, Hash Tables |
| 128 | SUBSECTION |
| 129 | Traversing a hash table |
| 130 | |
| 131 | @findex bfd_hash_traverse |
| 132 | The function <<bfd_hash_traverse>> may be used to traverse a |
| 133 | hash table, calling a function on each element. The traversal |
| 134 | is done in a random order. |
| 135 | |
| 136 | <<bfd_hash_traverse>> takes as arguments a function and a |
| 137 | generic <<void *>> pointer. The function is called with a |
| 138 | hash table entry (a <<struct bfd_hash_entry *>>) and the |
| 139 | generic pointer passed to <<bfd_hash_traverse>>. The function |
| 140 | must return a <<boolean>> value, which indicates whether to |
| 141 | continue traversing the hash table. If the function returns |
| 142 | <<FALSE>>, <<bfd_hash_traverse>> will stop the traversal and |
| 143 | return immediately. |
| 144 | |
| 145 | INODE |
| 146 | Deriving a New Hash Table Type, , Traversing a Hash Table, Hash Tables |
| 147 | SUBSECTION |
| 148 | Deriving a new hash table type |
| 149 | |
| 150 | Many uses of hash tables want to store additional information |
| 151 | which each entry in the hash table. Some also find it |
| 152 | convenient to store additional information with the hash table |
| 153 | itself. This may be done using a derived hash table. |
| 154 | |
| 155 | Since C is not an object oriented language, creating a derived |
| 156 | hash table requires sticking together some boilerplate |
| 157 | routines with a few differences specific to the type of hash |
| 158 | table you want to create. |
| 159 | |
| 160 | An example of a derived hash table is the linker hash table. |
| 161 | The structures for this are defined in <<bfdlink.h>>. The |
| 162 | functions are in <<linker.c>>. |
| 163 | |
| 164 | You may also derive a hash table from an already derived hash |
| 165 | table. For example, the a.out linker backend code uses a hash |
| 166 | table derived from the linker hash table. |
| 167 | |
| 168 | @menu |
| 169 | @* Define the Derived Structures:: |
| 170 | @* Write the Derived Creation Routine:: |
| 171 | @* Write Other Derived Routines:: |
| 172 | @end menu |
| 173 | |
| 174 | INODE |
| 175 | Define the Derived Structures, Write the Derived Creation Routine, Deriving a New Hash Table Type, Deriving a New Hash Table Type |
| 176 | SUBSUBSECTION |
| 177 | Define the derived structures |
| 178 | |
| 179 | You must define a structure for an entry in the hash table, |
| 180 | and a structure for the hash table itself. |
| 181 | |
| 182 | The first field in the structure for an entry in the hash |
| 183 | table must be of the type used for an entry in the hash table |
| 184 | you are deriving from. If you are deriving from a basic hash |
| 185 | table this is <<struct bfd_hash_entry>>, which is defined in |
| 186 | <<bfd.h>>. The first field in the structure for the hash |
| 187 | table itself must be of the type of the hash table you are |
| 188 | deriving from itself. If you are deriving from a basic hash |
| 189 | table, this is <<struct bfd_hash_table>>. |
| 190 | |
| 191 | For example, the linker hash table defines <<struct |
| 192 | bfd_link_hash_entry>> (in <<bfdlink.h>>). The first field, |
| 193 | <<root>>, is of type <<struct bfd_hash_entry>>. Similarly, |
| 194 | the first field in <<struct bfd_link_hash_table>>, <<table>>, |
| 195 | is of type <<struct bfd_hash_table>>. |
| 196 | |
| 197 | INODE |
| 198 | Write the Derived Creation Routine, Write Other Derived Routines, Define the Derived Structures, Deriving a New Hash Table Type |
| 199 | SUBSUBSECTION |
| 200 | Write the derived creation routine |
| 201 | |
| 202 | You must write a routine which will create and initialize an |
| 203 | entry in the hash table. This routine is passed as the |
| 204 | function argument to <<bfd_hash_table_init>>. |
| 205 | |
| 206 | In order to permit other hash tables to be derived from the |
| 207 | hash table you are creating, this routine must be written in a |
| 208 | standard way. |
| 209 | |
| 210 | The first argument to the creation routine is a pointer to a |
| 211 | hash table entry. This may be <<NULL>>, in which case the |
| 212 | routine should allocate the right amount of space. Otherwise |
| 213 | the space has already been allocated by a hash table type |
| 214 | derived from this one. |
| 215 | |
| 216 | After allocating space, the creation routine must call the |
| 217 | creation routine of the hash table type it is derived from, |
| 218 | passing in a pointer to the space it just allocated. This |
| 219 | will initialize any fields used by the base hash table. |
| 220 | |
| 221 | Finally the creation routine must initialize any local fields |
| 222 | for the new hash table type. |
| 223 | |
| 224 | Here is a boilerplate example of a creation routine. |
| 225 | @var{function_name} is the name of the routine. |
| 226 | @var{entry_type} is the type of an entry in the hash table you |
| 227 | are creating. @var{base_newfunc} is the name of the creation |
| 228 | routine of the hash table type your hash table is derived |
| 229 | from. |
| 230 | |
| 231 | EXAMPLE |
| 232 | |
| 233 | .struct bfd_hash_entry * |
| 234 | .@var{function_name} (struct bfd_hash_entry *entry, |
| 235 | . struct bfd_hash_table *table, |
| 236 | . const char *string) |
| 237 | .{ |
| 238 | . struct @var{entry_type} *ret = (@var{entry_type} *) entry; |
| 239 | . |
| 240 | . {* Allocate the structure if it has not already been allocated by a |
| 241 | . derived class. *} |
| 242 | . if (ret == NULL) |
| 243 | . { |
| 244 | . ret = bfd_hash_allocate (table, sizeof (* ret)); |
| 245 | . if (ret == NULL) |
| 246 | . return NULL; |
| 247 | . } |
| 248 | . |
| 249 | . {* Call the allocation method of the base class. *} |
| 250 | . ret = ((@var{entry_type} *) |
| 251 | . @var{base_newfunc} ((struct bfd_hash_entry *) ret, table, string)); |
| 252 | . |
| 253 | . {* Initialize the local fields here. *} |
| 254 | . |
| 255 | . return (struct bfd_hash_entry *) ret; |
| 256 | .} |
| 257 | |
| 258 | DESCRIPTION |
| 259 | The creation routine for the linker hash table, which is in |
| 260 | <<linker.c>>, looks just like this example. |
| 261 | @var{function_name} is <<_bfd_link_hash_newfunc>>. |
| 262 | @var{entry_type} is <<struct bfd_link_hash_entry>>. |
| 263 | @var{base_newfunc} is <<bfd_hash_newfunc>>, the creation |
| 264 | routine for a basic hash table. |
| 265 | |
| 266 | <<_bfd_link_hash_newfunc>> also initializes the local fields |
| 267 | in a linker hash table entry: <<type>>, <<written>> and |
| 268 | <<next>>. |
| 269 | |
| 270 | INODE |
| 271 | Write Other Derived Routines, , Write the Derived Creation Routine, Deriving a New Hash Table Type |
| 272 | SUBSUBSECTION |
| 273 | Write other derived routines |
| 274 | |
| 275 | You will want to write other routines for your new hash table, |
| 276 | as well. |
| 277 | |
| 278 | You will want an initialization routine which calls the |
| 279 | initialization routine of the hash table you are deriving from |
| 280 | and initializes any other local fields. For the linker hash |
| 281 | table, this is <<_bfd_link_hash_table_init>> in <<linker.c>>. |
| 282 | |
| 283 | You will want a lookup routine which calls the lookup routine |
| 284 | of the hash table you are deriving from and casts the result. |
| 285 | The linker hash table uses <<bfd_link_hash_lookup>> in |
| 286 | <<linker.c>> (this actually takes an additional argument which |
| 287 | it uses to decide how to return the looked up value). |
| 288 | |
| 289 | You may want a traversal routine. This should just call the |
| 290 | traversal routine of the hash table you are deriving from with |
| 291 | appropriate casts. The linker hash table uses |
| 292 | <<bfd_link_hash_traverse>> in <<linker.c>>. |
| 293 | |
| 294 | These routines may simply be defined as macros. For example, |
| 295 | the a.out backend linker hash table, which is derived from the |
| 296 | linker hash table, uses macros for the lookup and traversal |
| 297 | routines. These are <<aout_link_hash_lookup>> and |
| 298 | <<aout_link_hash_traverse>> in aoutx.h. |
| 299 | */ |
| 300 | |
| 301 | /* The default number of entries to use when creating a hash table. */ |
| 302 | #define DEFAULT_SIZE 4051 |
| 303 | |
| 304 | /* The following function returns a nearest prime number which is |
| 305 | greater than N, and near a power of two. Copied from libiberty. |
| 306 | Returns zero for ridiculously large N to signify an error. */ |
| 307 | |
| 308 | static unsigned long |
| 309 | higher_prime_number (unsigned long n) |
| 310 | { |
| 311 | /* These are primes that are near, but slightly smaller than, a |
| 312 | power of two. */ |
| 313 | static const unsigned long primes[] = |
| 314 | { |
| 315 | (unsigned long) 31, |
| 316 | (unsigned long) 61, |
| 317 | (unsigned long) 127, |
| 318 | (unsigned long) 251, |
| 319 | (unsigned long) 509, |
| 320 | (unsigned long) 1021, |
| 321 | (unsigned long) 2039, |
| 322 | (unsigned long) 4093, |
| 323 | (unsigned long) 8191, |
| 324 | (unsigned long) 16381, |
| 325 | (unsigned long) 32749, |
| 326 | (unsigned long) 65521, |
| 327 | (unsigned long) 131071, |
| 328 | (unsigned long) 262139, |
| 329 | (unsigned long) 524287, |
| 330 | (unsigned long) 1048573, |
| 331 | (unsigned long) 2097143, |
| 332 | (unsigned long) 4194301, |
| 333 | (unsigned long) 8388593, |
| 334 | (unsigned long) 16777213, |
| 335 | (unsigned long) 33554393, |
| 336 | (unsigned long) 67108859, |
| 337 | (unsigned long) 134217689, |
| 338 | (unsigned long) 268435399, |
| 339 | (unsigned long) 536870909, |
| 340 | (unsigned long) 1073741789, |
| 341 | (unsigned long) 2147483647, |
| 342 | /* 4294967291L */ |
| 343 | ((unsigned long) 2147483647) + ((unsigned long) 2147483644), |
| 344 | }; |
| 345 | |
| 346 | const unsigned long *low = &primes[0]; |
| 347 | const unsigned long *high = &primes[sizeof (primes) / sizeof (primes[0])]; |
| 348 | |
| 349 | while (low != high) |
| 350 | { |
| 351 | const unsigned long *mid = low + (high - low) / 2; |
| 352 | if (n >= *mid) |
| 353 | low = mid + 1; |
| 354 | else |
| 355 | high = mid; |
| 356 | } |
| 357 | |
| 358 | if (n >= *low) |
| 359 | return 0; |
| 360 | |
| 361 | return *low; |
| 362 | } |
| 363 | |
| 364 | static unsigned long bfd_default_hash_table_size = DEFAULT_SIZE; |
| 365 | |
| 366 | /* Create a new hash table, given a number of entries. */ |
| 367 | |
| 368 | bfd_boolean |
| 369 | bfd_hash_table_init_n (struct bfd_hash_table *table, |
| 370 | struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, |
| 371 | struct bfd_hash_table *, |
| 372 | const char *), |
| 373 | unsigned int entsize, |
| 374 | unsigned int size) |
| 375 | { |
| 376 | unsigned long alloc; |
| 377 | |
| 378 | alloc = size; |
| 379 | alloc *= sizeof (struct bfd_hash_entry *); |
| 380 | if (alloc / sizeof (struct bfd_hash_entry *) != size) |
| 381 | { |
| 382 | bfd_set_error (bfd_error_no_memory); |
| 383 | return FALSE; |
| 384 | } |
| 385 | |
| 386 | table->memory = (void *) objalloc_create (); |
| 387 | if (table->memory == NULL) |
| 388 | { |
| 389 | bfd_set_error (bfd_error_no_memory); |
| 390 | return FALSE; |
| 391 | } |
| 392 | table->table = (struct bfd_hash_entry **) |
| 393 | objalloc_alloc ((struct objalloc *) table->memory, alloc); |
| 394 | if (table->table == NULL) |
| 395 | { |
| 396 | bfd_set_error (bfd_error_no_memory); |
| 397 | return FALSE; |
| 398 | } |
| 399 | memset ((void *) table->table, 0, alloc); |
| 400 | table->size = size; |
| 401 | table->entsize = entsize; |
| 402 | table->count = 0; |
| 403 | table->frozen = 0; |
| 404 | table->newfunc = newfunc; |
| 405 | return TRUE; |
| 406 | } |
| 407 | |
| 408 | /* Create a new hash table with the default number of entries. */ |
| 409 | |
| 410 | bfd_boolean |
| 411 | bfd_hash_table_init (struct bfd_hash_table *table, |
| 412 | struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, |
| 413 | struct bfd_hash_table *, |
| 414 | const char *), |
| 415 | unsigned int entsize) |
| 416 | { |
| 417 | return bfd_hash_table_init_n (table, newfunc, entsize, |
| 418 | bfd_default_hash_table_size); |
| 419 | } |
| 420 | |
| 421 | /* Free a hash table. */ |
| 422 | |
| 423 | void |
| 424 | bfd_hash_table_free (struct bfd_hash_table *table) |
| 425 | { |
| 426 | objalloc_free ((struct objalloc *) table->memory); |
| 427 | table->memory = NULL; |
| 428 | } |
| 429 | |
| 430 | static inline unsigned long |
| 431 | bfd_hash_hash (const char *string, unsigned int *lenp) |
| 432 | { |
| 433 | const unsigned char *s; |
| 434 | unsigned long hash; |
| 435 | unsigned int len; |
| 436 | unsigned int c; |
| 437 | |
| 438 | hash = 0; |
| 439 | len = 0; |
| 440 | s = (const unsigned char *) string; |
| 441 | while ((c = *s++) != '\0') |
| 442 | { |
| 443 | hash += c + (c << 17); |
| 444 | hash ^= hash >> 2; |
| 445 | } |
| 446 | len = (s - (const unsigned char *) string) - 1; |
| 447 | hash += len + (len << 17); |
| 448 | hash ^= hash >> 2; |
| 449 | if (lenp != NULL) |
| 450 | *lenp = len; |
| 451 | return hash; |
| 452 | } |
| 453 | |
| 454 | /* Look up a string in a hash table. */ |
| 455 | |
| 456 | struct bfd_hash_entry * |
| 457 | bfd_hash_lookup (struct bfd_hash_table *table, |
| 458 | const char *string, |
| 459 | bfd_boolean create, |
| 460 | bfd_boolean copy) |
| 461 | { |
| 462 | unsigned long hash; |
| 463 | struct bfd_hash_entry *hashp; |
| 464 | unsigned int len; |
| 465 | unsigned int _index; |
| 466 | |
| 467 | hash = bfd_hash_hash (string, &len); |
| 468 | _index = hash % table->size; |
| 469 | for (hashp = table->table[_index]; |
| 470 | hashp != NULL; |
| 471 | hashp = hashp->next) |
| 472 | { |
| 473 | if (hashp->hash == hash |
| 474 | && strcmp (hashp->string, string) == 0) |
| 475 | return hashp; |
| 476 | } |
| 477 | |
| 478 | if (! create) |
| 479 | return NULL; |
| 480 | |
| 481 | if (copy) |
| 482 | { |
| 483 | char *new_string; |
| 484 | |
| 485 | new_string = (char *) objalloc_alloc ((struct objalloc *) table->memory, |
| 486 | len + 1); |
| 487 | if (!new_string) |
| 488 | { |
| 489 | bfd_set_error (bfd_error_no_memory); |
| 490 | return NULL; |
| 491 | } |
| 492 | memcpy (new_string, string, len + 1); |
| 493 | string = new_string; |
| 494 | } |
| 495 | |
| 496 | return bfd_hash_insert (table, string, hash); |
| 497 | } |
| 498 | |
| 499 | /* Insert an entry in a hash table. */ |
| 500 | |
| 501 | struct bfd_hash_entry * |
| 502 | bfd_hash_insert (struct bfd_hash_table *table, |
| 503 | const char *string, |
| 504 | unsigned long hash) |
| 505 | { |
| 506 | struct bfd_hash_entry *hashp; |
| 507 | unsigned int _index; |
| 508 | |
| 509 | hashp = (*table->newfunc) (NULL, table, string); |
| 510 | if (hashp == NULL) |
| 511 | return NULL; |
| 512 | hashp->string = string; |
| 513 | hashp->hash = hash; |
| 514 | _index = hash % table->size; |
| 515 | hashp->next = table->table[_index]; |
| 516 | table->table[_index] = hashp; |
| 517 | table->count++; |
| 518 | |
| 519 | if (!table->frozen && table->count > table->size * 3 / 4) |
| 520 | { |
| 521 | unsigned long newsize = higher_prime_number (table->size); |
| 522 | struct bfd_hash_entry **newtable; |
| 523 | unsigned int hi; |
| 524 | unsigned long alloc = newsize * sizeof (struct bfd_hash_entry *); |
| 525 | |
| 526 | /* If we can't find a higher prime, or we can't possibly alloc |
| 527 | that much memory, don't try to grow the table. */ |
| 528 | if (newsize == 0 || alloc / sizeof (struct bfd_hash_entry *) != newsize) |
| 529 | { |
| 530 | table->frozen = 1; |
| 531 | return hashp; |
| 532 | } |
| 533 | |
| 534 | newtable = ((struct bfd_hash_entry **) |
| 535 | objalloc_alloc ((struct objalloc *) table->memory, alloc)); |
| 536 | if (newtable == NULL) |
| 537 | { |
| 538 | table->frozen = 1; |
| 539 | return hashp; |
| 540 | } |
| 541 | memset (newtable, 0, alloc); |
| 542 | |
| 543 | for (hi = 0; hi < table->size; hi ++) |
| 544 | while (table->table[hi]) |
| 545 | { |
| 546 | struct bfd_hash_entry *chain = table->table[hi]; |
| 547 | struct bfd_hash_entry *chain_end = chain; |
| 548 | |
| 549 | while (chain_end->next && chain_end->next->hash == chain->hash) |
| 550 | chain_end = chain_end->next; |
| 551 | |
| 552 | table->table[hi] = chain_end->next; |
| 553 | _index = chain->hash % newsize; |
| 554 | chain_end->next = newtable[_index]; |
| 555 | newtable[_index] = chain; |
| 556 | } |
| 557 | table->table = newtable; |
| 558 | table->size = newsize; |
| 559 | } |
| 560 | |
| 561 | return hashp; |
| 562 | } |
| 563 | |
| 564 | /* Rename an entry in a hash table. */ |
| 565 | |
| 566 | void |
| 567 | bfd_hash_rename (struct bfd_hash_table *table, |
| 568 | const char *string, |
| 569 | struct bfd_hash_entry *ent) |
| 570 | { |
| 571 | unsigned int _index; |
| 572 | struct bfd_hash_entry **pph; |
| 573 | |
| 574 | _index = ent->hash % table->size; |
| 575 | for (pph = &table->table[_index]; *pph != NULL; pph = &(*pph)->next) |
| 576 | if (*pph == ent) |
| 577 | break; |
| 578 | if (*pph == NULL) |
| 579 | abort (); |
| 580 | |
| 581 | *pph = ent->next; |
| 582 | ent->string = string; |
| 583 | ent->hash = bfd_hash_hash (string, NULL); |
| 584 | _index = ent->hash % table->size; |
| 585 | ent->next = table->table[_index]; |
| 586 | table->table[_index] = ent; |
| 587 | } |
| 588 | |
| 589 | /* Replace an entry in a hash table. */ |
| 590 | |
| 591 | void |
| 592 | bfd_hash_replace (struct bfd_hash_table *table, |
| 593 | struct bfd_hash_entry *old, |
| 594 | struct bfd_hash_entry *nw) |
| 595 | { |
| 596 | unsigned int _index; |
| 597 | struct bfd_hash_entry **pph; |
| 598 | |
| 599 | _index = old->hash % table->size; |
| 600 | for (pph = &table->table[_index]; |
| 601 | (*pph) != NULL; |
| 602 | pph = &(*pph)->next) |
| 603 | { |
| 604 | if (*pph == old) |
| 605 | { |
| 606 | *pph = nw; |
| 607 | return; |
| 608 | } |
| 609 | } |
| 610 | |
| 611 | abort (); |
| 612 | } |
| 613 | |
| 614 | /* Allocate space in a hash table. */ |
| 615 | |
| 616 | void * |
| 617 | bfd_hash_allocate (struct bfd_hash_table *table, |
| 618 | unsigned int size) |
| 619 | { |
| 620 | void * ret; |
| 621 | |
| 622 | ret = objalloc_alloc ((struct objalloc *) table->memory, size); |
| 623 | if (ret == NULL && size != 0) |
| 624 | bfd_set_error (bfd_error_no_memory); |
| 625 | return ret; |
| 626 | } |
| 627 | |
| 628 | /* Base method for creating a new hash table entry. */ |
| 629 | |
| 630 | struct bfd_hash_entry * |
| 631 | bfd_hash_newfunc (struct bfd_hash_entry *entry, |
| 632 | struct bfd_hash_table *table, |
| 633 | const char *string ATTRIBUTE_UNUSED) |
| 634 | { |
| 635 | if (entry == NULL) |
| 636 | entry = (struct bfd_hash_entry *) bfd_hash_allocate (table, |
| 637 | sizeof (* entry)); |
| 638 | return entry; |
| 639 | } |
| 640 | |
| 641 | /* Traverse a hash table. */ |
| 642 | |
| 643 | void |
| 644 | bfd_hash_traverse (struct bfd_hash_table *table, |
| 645 | bfd_boolean (*func) (struct bfd_hash_entry *, void *), |
| 646 | void * info) |
| 647 | { |
| 648 | unsigned int i; |
| 649 | |
| 650 | table->frozen = 1; |
| 651 | for (i = 0; i < table->size; i++) |
| 652 | { |
| 653 | struct bfd_hash_entry *p; |
| 654 | |
| 655 | for (p = table->table[i]; p != NULL; p = p->next) |
| 656 | if (! (*func) (p, info)) |
| 657 | goto out; |
| 658 | } |
| 659 | out: |
| 660 | table->frozen = 0; |
| 661 | } |
| 662 | \f |
| 663 | unsigned long |
| 664 | bfd_hash_set_default_size (unsigned long hash_size) |
| 665 | { |
| 666 | /* Extend this prime list if you want more granularity of hash table size. */ |
| 667 | static const unsigned long hash_size_primes[] = |
| 668 | { |
| 669 | 31, 61, 127, 251, 509, 1021, 2039, 4091, 8191, 16381, 32749, 65537 |
| 670 | }; |
| 671 | unsigned int _index; |
| 672 | |
| 673 | /* Work out best prime number near the hash_size. */ |
| 674 | for (_index = 0; _index < ARRAY_SIZE (hash_size_primes) - 1; ++_index) |
| 675 | if (hash_size <= hash_size_primes[_index]) |
| 676 | break; |
| 677 | |
| 678 | bfd_default_hash_table_size = hash_size_primes[_index]; |
| 679 | return bfd_default_hash_table_size; |
| 680 | } |
| 681 | \f |
| 682 | /* A few different object file formats (a.out, COFF, ELF) use a string |
| 683 | table. These functions support adding strings to a string table, |
| 684 | returning the byte offset, and writing out the table. |
| 685 | |
| 686 | Possible improvements: |
| 687 | + look for strings matching trailing substrings of other strings |
| 688 | + better data structures? balanced trees? |
| 689 | + look at reducing memory use elsewhere -- maybe if we didn't have |
| 690 | to construct the entire symbol table at once, we could get by |
| 691 | with smaller amounts of VM? (What effect does that have on the |
| 692 | string table reductions?) */ |
| 693 | |
| 694 | /* An entry in the strtab hash table. */ |
| 695 | |
| 696 | struct strtab_hash_entry |
| 697 | { |
| 698 | struct bfd_hash_entry root; |
| 699 | /* Index in string table. */ |
| 700 | bfd_size_type index; |
| 701 | /* Next string in strtab. */ |
| 702 | struct strtab_hash_entry *next; |
| 703 | }; |
| 704 | |
| 705 | /* The strtab hash table. */ |
| 706 | |
| 707 | struct bfd_strtab_hash |
| 708 | { |
| 709 | struct bfd_hash_table table; |
| 710 | /* Size of strtab--also next available index. */ |
| 711 | bfd_size_type size; |
| 712 | /* First string in strtab. */ |
| 713 | struct strtab_hash_entry *first; |
| 714 | /* Last string in strtab. */ |
| 715 | struct strtab_hash_entry *last; |
| 716 | /* Whether to precede strings with a two byte length, as in the |
| 717 | XCOFF .debug section. */ |
| 718 | bfd_boolean xcoff; |
| 719 | }; |
| 720 | |
| 721 | /* Routine to create an entry in a strtab. */ |
| 722 | |
| 723 | static struct bfd_hash_entry * |
| 724 | strtab_hash_newfunc (struct bfd_hash_entry *entry, |
| 725 | struct bfd_hash_table *table, |
| 726 | const char *string) |
| 727 | { |
| 728 | struct strtab_hash_entry *ret = (struct strtab_hash_entry *) entry; |
| 729 | |
| 730 | /* Allocate the structure if it has not already been allocated by a |
| 731 | subclass. */ |
| 732 | if (ret == NULL) |
| 733 | ret = (struct strtab_hash_entry *) bfd_hash_allocate (table, |
| 734 | sizeof (* ret)); |
| 735 | if (ret == NULL) |
| 736 | return NULL; |
| 737 | |
| 738 | /* Call the allocation method of the superclass. */ |
| 739 | ret = (struct strtab_hash_entry *) |
| 740 | bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string); |
| 741 | |
| 742 | if (ret) |
| 743 | { |
| 744 | /* Initialize the local fields. */ |
| 745 | ret->index = (bfd_size_type) -1; |
| 746 | ret->next = NULL; |
| 747 | } |
| 748 | |
| 749 | return (struct bfd_hash_entry *) ret; |
| 750 | } |
| 751 | |
| 752 | /* Look up an entry in an strtab. */ |
| 753 | |
| 754 | #define strtab_hash_lookup(t, string, create, copy) \ |
| 755 | ((struct strtab_hash_entry *) \ |
| 756 | bfd_hash_lookup (&(t)->table, (string), (create), (copy))) |
| 757 | |
| 758 | /* Create a new strtab. */ |
| 759 | |
| 760 | struct bfd_strtab_hash * |
| 761 | _bfd_stringtab_init (void) |
| 762 | { |
| 763 | struct bfd_strtab_hash *table; |
| 764 | bfd_size_type amt = sizeof (* table); |
| 765 | |
| 766 | table = (struct bfd_strtab_hash *) bfd_malloc (amt); |
| 767 | if (table == NULL) |
| 768 | return NULL; |
| 769 | |
| 770 | if (!bfd_hash_table_init (&table->table, strtab_hash_newfunc, |
| 771 | sizeof (struct strtab_hash_entry))) |
| 772 | { |
| 773 | free (table); |
| 774 | return NULL; |
| 775 | } |
| 776 | |
| 777 | table->size = 0; |
| 778 | table->first = NULL; |
| 779 | table->last = NULL; |
| 780 | table->xcoff = FALSE; |
| 781 | |
| 782 | return table; |
| 783 | } |
| 784 | |
| 785 | /* Create a new strtab in which the strings are output in the format |
| 786 | used in the XCOFF .debug section: a two byte length precedes each |
| 787 | string. */ |
| 788 | |
| 789 | struct bfd_strtab_hash * |
| 790 | _bfd_xcoff_stringtab_init (void) |
| 791 | { |
| 792 | struct bfd_strtab_hash *ret; |
| 793 | |
| 794 | ret = _bfd_stringtab_init (); |
| 795 | if (ret != NULL) |
| 796 | ret->xcoff = TRUE; |
| 797 | return ret; |
| 798 | } |
| 799 | |
| 800 | /* Free a strtab. */ |
| 801 | |
| 802 | void |
| 803 | _bfd_stringtab_free (struct bfd_strtab_hash *table) |
| 804 | { |
| 805 | bfd_hash_table_free (&table->table); |
| 806 | free (table); |
| 807 | } |
| 808 | |
| 809 | /* Get the index of a string in a strtab, adding it if it is not |
| 810 | already present. If HASH is FALSE, we don't really use the hash |
| 811 | table, and we don't eliminate duplicate strings. */ |
| 812 | |
| 813 | bfd_size_type |
| 814 | _bfd_stringtab_add (struct bfd_strtab_hash *tab, |
| 815 | const char *str, |
| 816 | bfd_boolean hash, |
| 817 | bfd_boolean copy) |
| 818 | { |
| 819 | struct strtab_hash_entry *entry; |
| 820 | |
| 821 | if (hash) |
| 822 | { |
| 823 | entry = strtab_hash_lookup (tab, str, TRUE, copy); |
| 824 | if (entry == NULL) |
| 825 | return (bfd_size_type) -1; |
| 826 | } |
| 827 | else |
| 828 | { |
| 829 | entry = (struct strtab_hash_entry *) bfd_hash_allocate (&tab->table, |
| 830 | sizeof (* entry)); |
| 831 | if (entry == NULL) |
| 832 | return (bfd_size_type) -1; |
| 833 | if (! copy) |
| 834 | entry->root.string = str; |
| 835 | else |
| 836 | { |
| 837 | char *n; |
| 838 | |
| 839 | n = (char *) bfd_hash_allocate (&tab->table, strlen (str) + 1); |
| 840 | if (n == NULL) |
| 841 | return (bfd_size_type) -1; |
| 842 | entry->root.string = n; |
| 843 | } |
| 844 | entry->index = (bfd_size_type) -1; |
| 845 | entry->next = NULL; |
| 846 | } |
| 847 | |
| 848 | if (entry->index == (bfd_size_type) -1) |
| 849 | { |
| 850 | entry->index = tab->size; |
| 851 | tab->size += strlen (str) + 1; |
| 852 | if (tab->xcoff) |
| 853 | { |
| 854 | entry->index += 2; |
| 855 | tab->size += 2; |
| 856 | } |
| 857 | if (tab->first == NULL) |
| 858 | tab->first = entry; |
| 859 | else |
| 860 | tab->last->next = entry; |
| 861 | tab->last = entry; |
| 862 | } |
| 863 | |
| 864 | return entry->index; |
| 865 | } |
| 866 | |
| 867 | /* Get the number of bytes in a strtab. */ |
| 868 | |
| 869 | bfd_size_type |
| 870 | _bfd_stringtab_size (struct bfd_strtab_hash *tab) |
| 871 | { |
| 872 | return tab->size; |
| 873 | } |
| 874 | |
| 875 | /* Write out a strtab. ABFD must already be at the right location in |
| 876 | the file. */ |
| 877 | |
| 878 | bfd_boolean |
| 879 | _bfd_stringtab_emit (bfd *abfd, struct bfd_strtab_hash *tab) |
| 880 | { |
| 881 | bfd_boolean xcoff; |
| 882 | struct strtab_hash_entry *entry; |
| 883 | |
| 884 | xcoff = tab->xcoff; |
| 885 | |
| 886 | for (entry = tab->first; entry != NULL; entry = entry->next) |
| 887 | { |
| 888 | const char *str; |
| 889 | size_t len; |
| 890 | |
| 891 | str = entry->root.string; |
| 892 | len = strlen (str) + 1; |
| 893 | |
| 894 | if (xcoff) |
| 895 | { |
| 896 | bfd_byte buf[2]; |
| 897 | |
| 898 | /* The output length includes the null byte. */ |
| 899 | bfd_put_16 (abfd, (bfd_vma) len, buf); |
| 900 | if (bfd_bwrite ((void *) buf, (bfd_size_type) 2, abfd) != 2) |
| 901 | return FALSE; |
| 902 | } |
| 903 | |
| 904 | if (bfd_bwrite ((void *) str, (bfd_size_type) len, abfd) != len) |
| 905 | return FALSE; |
| 906 | } |
| 907 | |
| 908 | return TRUE; |
| 909 | } |