1 /* Functions to support a pool of allocatable objects. 2 Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 3 2007, 2008, 2010 Free Software Foundation, Inc. 4 Contributed by Daniel Berlin <dan@cgsoftware.com> 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 #include "config.h" 23 #include "system.h" 24 #include "alloc-pool.h" 25 #include "hashtab.h" 26 27 #define align_eight(x) (((x+7) >> 3) << 3) 28 29 /* The internal allocation object. */ 30 typedef struct allocation_object_def 31 { 32 #ifdef ENABLE_CHECKING 33 /* The ID of alloc pool which the object was allocated from. */ 34 ALLOC_POOL_ID_TYPE id; 35 #endif 36 37 union 38 { 39 /* The data of the object. */ 40 char data[1]; 41 42 /* Because we want any type of data to be well aligned after the ID, 43 the following elements are here. They are never accessed so 44 the allocated object may be even smaller than this structure. 45 We do not care about alignment for floating-point types. */ 46 char *align_p; 47 HOST_WIDEST_INT align_i; 48 } u; 49 } allocation_object; 50 51 /* Convert a pointer to allocation_object from a pointer to user data. */ 52 #define ALLOCATION_OBJECT_PTR_FROM_USER_PTR(X) \ 53 ((allocation_object *) (((char *) (X)) \ 54 - offsetof (allocation_object, u.data))) 55 56 /* Convert a pointer to user data from a pointer to allocation_object. */ 57 #define USER_PTR_FROM_ALLOCATION_OBJECT_PTR(X) \ 58 ((void *) (((allocation_object *) (X))->u.data)) 59 60 #ifdef ENABLE_CHECKING 61 /* Last used ID. */ 62 static ALLOC_POOL_ID_TYPE last_id; 63 #endif 64 65 #ifdef GATHER_STATISTICS 66 67 /* Store information about each particular alloc_pool. Note that this 68 will underestimate the amount the amount of storage used by a small amount: 69 1) The overhead in a pool is not accounted for. 70 2) The unallocated elements in a block are not accounted for. Note 71 that this can at worst case be one element smaller that the block 72 size for that pool. */ 73 struct alloc_pool_descriptor 74 { 75 const char *name; 76 /* Number of pools allocated. */ 77 unsigned long created; 78 /* Gross allocated storage. */ 79 unsigned long allocated; 80 /* Amount of currently active storage. */ 81 unsigned long current; 82 /* Peak amount of storage used. */ 83 unsigned long peak; 84 /* Size of element in the pool. */ 85 int elt_size; 86 }; 87 88 /* Hashtable mapping alloc_pool names to descriptors. */ 89 static htab_t alloc_pool_hash; 90 91 /* Hashtable helpers. */ 92 static hashval_t 93 hash_descriptor (const void *p) 94 { 95 const struct alloc_pool_descriptor *const d = 96 (const struct alloc_pool_descriptor * )p; 97 return htab_hash_pointer (d->name); 98 } 99 static int 100 eq_descriptor (const void *p1, const void *p2) 101 { 102 const struct alloc_pool_descriptor *const d = 103 (const struct alloc_pool_descriptor *) p1; 104 return d->name == p2; 105 } 106 107 /* For given name, return descriptor, create new if needed. */ 108 static struct alloc_pool_descriptor * 109 alloc_pool_descriptor (const char *name) 110 { 111 struct alloc_pool_descriptor **slot; 112 113 if (!alloc_pool_hash) 114 alloc_pool_hash = htab_create (10, hash_descriptor, eq_descriptor, NULL); 115 116 slot = (struct alloc_pool_descriptor **) 117 htab_find_slot_with_hash (alloc_pool_hash, name, 118 htab_hash_pointer (name), 119 INSERT); 120 if (*slot) 121 return *slot; 122 *slot = XCNEW (struct alloc_pool_descriptor); 123 (*slot)->name = name; 124 return *slot; 125 } 126 #endif 127 128 /* Create a pool of things of size SIZE, with NUM in each block we 129 allocate. */ 130 131 alloc_pool 132 create_alloc_pool (const char *name, size_t size, size_t num) 133 { 134 alloc_pool pool; 135 size_t header_size; 136 #ifdef GATHER_STATISTICS 137 struct alloc_pool_descriptor *desc; 138 #endif 139 140 gcc_checking_assert (name); 141 142 /* Make size large enough to store the list header. */ 143 if (size < sizeof (alloc_pool_list)) 144 size = sizeof (alloc_pool_list); 145 146 /* Now align the size to a multiple of 4. */ 147 size = align_eight (size); 148 149 #ifdef ENABLE_CHECKING 150 /* Add the aligned size of ID. */ 151 size += offsetof (allocation_object, u.data); 152 #endif 153 154 /* Um, we can't really allocate 0 elements per block. */ 155 gcc_checking_assert (num); 156 157 /* Allocate memory for the pool structure. */ 158 pool = XNEW (struct alloc_pool_def); 159 160 /* Now init the various pieces of our pool structure. */ 161 pool->name = /*xstrdup (name)*/name; 162 #ifdef GATHER_STATISTICS 163 desc = alloc_pool_descriptor (name); 164 desc->elt_size = size; 165 desc->created++; 166 #endif 167 pool->elt_size = size; 168 pool->elts_per_block = num; 169 170 /* List header size should be a multiple of 8. */ 171 header_size = align_eight (sizeof (struct alloc_pool_list_def)); 172 173 pool->block_size = (size * num) + header_size; 174 pool->returned_free_list = NULL; 175 pool->virgin_free_list = NULL; 176 pool->virgin_elts_remaining = 0; 177 pool->elts_allocated = 0; 178 pool->elts_free = 0; 179 pool->blocks_allocated = 0; 180 pool->block_list = NULL; 181 182 #ifdef ENABLE_CHECKING 183 /* Increase the last used ID and use it for this pool. 184 ID == 0 is used for free elements of pool so skip it. */ 185 last_id++; 186 if (last_id == 0) 187 last_id++; 188 189 pool->id = last_id; 190 #endif 191 192 return (pool); 193 } 194 195 /* Free all memory allocated for the given memory pool. */ 196 void 197 empty_alloc_pool (alloc_pool pool) 198 { 199 alloc_pool_list block, next_block; 200 #ifdef GATHER_STATISTICS 201 struct alloc_pool_descriptor *desc = alloc_pool_descriptor (pool->name); 202 #endif 203 204 gcc_checking_assert (pool); 205 206 /* Free each block allocated to the pool. */ 207 for (block = pool->block_list; block != NULL; block = next_block) 208 { 209 next_block = block->next; 210 free (block); 211 } 212 213 #ifdef GATHER_STATISTICS 214 desc->current -= (pool->elts_allocated - pool->elts_free) * pool->elt_size; 215 #endif 216 pool->returned_free_list = NULL; 217 pool->virgin_free_list = NULL; 218 pool->virgin_elts_remaining = 0; 219 pool->elts_allocated = 0; 220 pool->elts_free = 0; 221 pool->blocks_allocated = 0; 222 pool->block_list = NULL; 223 } 224 225 /* Free all memory allocated for the given memory pool and the pool itself. */ 226 void 227 free_alloc_pool (alloc_pool pool) 228 { 229 /* First empty the pool. */ 230 empty_alloc_pool (pool); 231 #ifdef ENABLE_CHECKING 232 memset (pool, 0xaf, sizeof (*pool)); 233 #endif 234 /* Lastly, free the pool. */ 235 free (pool); 236 } 237 238 /* Frees the alloc_pool, if it is empty and zero *POOL in this case. */ 239 void 240 free_alloc_pool_if_empty (alloc_pool *pool) 241 { 242 if ((*pool)->elts_free == (*pool)->elts_allocated) 243 { 244 free_alloc_pool (*pool); 245 *pool = NULL; 246 } 247 } 248 249 /* Allocates one element from the pool specified. */ 250 void * 251 pool_alloc (alloc_pool pool) 252 { 253 alloc_pool_list header; 254 #ifdef GATHER_STATISTICS 255 struct alloc_pool_descriptor *desc = alloc_pool_descriptor (pool->name); 256 257 desc->allocated += pool->elt_size; 258 desc->current += pool->elt_size; 259 if (desc->peak < desc->current) 260 desc->peak = desc->current; 261 #endif 262 263 gcc_checking_assert (pool); 264 265 /* If there are no more free elements, make some more!. */ 266 if (!pool->returned_free_list) 267 { 268 char *block; 269 if (!pool->virgin_elts_remaining) 270 { 271 alloc_pool_list block_header; 272 273 /* Make the block. */ 274 block = XNEWVEC (char, pool->block_size); 275 block_header = (alloc_pool_list) block; 276 block += align_eight (sizeof (struct alloc_pool_list_def)); 277 278 /* Throw it on the block list. */ 279 block_header->next = pool->block_list; 280 pool->block_list = block_header; 281 282 /* Make the block available for allocation. */ 283 pool->virgin_free_list = block; 284 pool->virgin_elts_remaining = pool->elts_per_block; 285 286 /* Also update the number of elements we have free/allocated, and 287 increment the allocated block count. */ 288 pool->elts_allocated += pool->elts_per_block; 289 pool->elts_free += pool->elts_per_block; 290 pool->blocks_allocated += 1; 291 } 292 293 294 /* We now know that we can take the first elt off the virgin list and 295 put it on the returned list. */ 296 block = pool->virgin_free_list; 297 header = (alloc_pool_list) USER_PTR_FROM_ALLOCATION_OBJECT_PTR (block); 298 header->next = NULL; 299 #ifdef ENABLE_CHECKING 300 /* Mark the element to be free. */ 301 ((allocation_object *) block)->id = 0; 302 #endif 303 pool->returned_free_list = header; 304 pool->virgin_free_list += pool->elt_size; 305 pool->virgin_elts_remaining--; 306 307 } 308 309 /* Pull the first free element from the free list, and return it. */ 310 header = pool->returned_free_list; 311 pool->returned_free_list = header->next; 312 pool->elts_free--; 313 314 #ifdef ENABLE_CHECKING 315 /* Set the ID for element. */ 316 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (header)->id = pool->id; 317 #endif 318 319 return ((void *) header); 320 } 321 322 /* Puts PTR back on POOL's free list. */ 323 void 324 pool_free (alloc_pool pool, void *ptr) 325 { 326 alloc_pool_list header; 327 #ifdef GATHER_STATISTICS 328 struct alloc_pool_descriptor *desc = alloc_pool_descriptor (pool->name); 329 #endif 330 331 332 #ifdef ENABLE_CHECKING 333 gcc_assert (ptr 334 /* Check if we free more than we allocated, which is Bad (TM). */ 335 && pool->elts_free < pool->elts_allocated 336 /* Check whether the PTR was allocated from POOL. */ 337 && pool->id == ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id); 338 339 memset (ptr, 0xaf, pool->elt_size - offsetof (allocation_object, u.data)); 340 341 /* Mark the element to be free. */ 342 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id = 0; 343 #else 344 #endif 345 346 header = (alloc_pool_list) ptr; 347 header->next = pool->returned_free_list; 348 pool->returned_free_list = header; 349 pool->elts_free++; 350 351 #ifdef GATHER_STATISTICS 352 desc->current -= pool->elt_size; 353 #endif 354 355 } 356 /* Output per-alloc_pool statistics. */ 357 #ifdef GATHER_STATISTICS 358 359 /* Used to accumulate statistics about alloc_pool sizes. */ 360 struct output_info 361 { 362 unsigned long total_created; 363 unsigned long total_allocated; 364 }; 365 366 /* Called via htab_traverse. Output alloc_pool descriptor pointed out by SLOT 367 and update statistics. */ 368 static int 369 print_statistics (void **slot, void *b) 370 { 371 struct alloc_pool_descriptor *d = (struct alloc_pool_descriptor *) *slot; 372 struct output_info *i = (struct output_info *) b; 373 374 if (d->allocated) 375 { 376 fprintf (stderr, "%-22s %6d %10lu %10lu(%10lu) %10lu(%10lu) %10lu(%10lu)\n", d->name, 377 d->elt_size, d->created, d->allocated, d->allocated / d->elt_size, 378 d->peak, d->peak / d->elt_size, 379 d->current, d->current / d->elt_size); 380 i->total_allocated += d->allocated; 381 i->total_created += d->created; 382 } 383 return 1; 384 } 385 #endif 386 387 /* Output per-alloc_pool memory usage statistics. */ 388 void 389 dump_alloc_pool_statistics (void) 390 { 391 #ifdef GATHER_STATISTICS 392 struct output_info info; 393 394 if (!alloc_pool_hash) 395 return; 396 397 fprintf (stderr, "\nAlloc-pool Kind Elt size Pools Allocated (elts) Peak (elts) Leak (elts)\n"); 398 fprintf (stderr, "--------------------------------------------------------------------------------------------------------------\n"); 399 info.total_created = 0; 400 info.total_allocated = 0; 401 htab_traverse (alloc_pool_hash, print_statistics, &info); 402 fprintf (stderr, "--------------------------------------------------------------------------------------------------------------\n"); 403 fprintf (stderr, "%-22s %7lu %10lu\n", 404 "Total", info.total_created, info.total_allocated); 405 fprintf (stderr, "--------------------------------------------------------------------------------------------------------------\n"); 406 #endif 407 } 408