1 /* Functions to support a pool of allocatable objects.
2 Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@cgsoftware.com>
6 This file is part of GCC.
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 2, or (at your option) any later
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
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
25 #include "alloc-pool.h"
28 #define align_eight(x) (((x+7) >> 3) << 3)
30 /* The internal allocation object. */
31 typedef struct allocation_object_def
33 #ifdef ENABLE_CHECKING
34 /* The ID of alloc pool which the object was allocated from. */
35 ALLOC_POOL_ID_TYPE id;
40 /* The data of the object. */
43 /* Because we want any type of data to be well aligned after the ID,
44 the following elements are here. They are never accessed so
45 the allocated object may be even smaller than this structure. */
47 HOST_WIDEST_INT align_i;
52 /* Convert a pointer to allocation_object from a pointer to user data. */
53 #define ALLOCATION_OBJECT_PTR_FROM_USER_PTR(X) \
54 ((allocation_object *) (((char *) (X)) \
55 - offsetof (allocation_object, u.data)))
57 /* Convert a pointer to user data from a pointer to allocation_object. */
58 #define USER_PTR_FROM_ALLOCATION_OBJECT_PTR(X) \
59 ((void *) (((allocation_object *) (X))->u.data))
61 #ifdef ENABLE_CHECKING
63 static ALLOC_POOL_ID_TYPE last_id;
66 #ifdef GATHER_STATISTICS
68 /* Store information about each particular alloc_pool. */
69 struct alloc_pool_descriptor
78 /* Hashtable mapping alloc_pool names to descriptors. */
79 static htab_t alloc_pool_hash;
81 /* Hashtable helpers. */
83 hash_descriptor (const void *p)
85 const struct alloc_pool_descriptor *d = p;
86 return htab_hash_pointer (d->name);
89 eq_descriptor (const void *p1, const void *p2)
91 const struct alloc_pool_descriptor *d = p1;
95 /* For given name, return descriptor, create new if needed. */
96 static struct alloc_pool_descriptor *
97 alloc_pool_descriptor (const char *name)
99 struct alloc_pool_descriptor **slot;
101 if (!alloc_pool_hash)
102 alloc_pool_hash = htab_create (10, hash_descriptor, eq_descriptor, NULL);
104 slot = (struct alloc_pool_descriptor **)
105 htab_find_slot_with_hash (alloc_pool_hash, name,
106 htab_hash_pointer (name),
110 *slot = xcalloc (sizeof (**slot), 1);
111 (*slot)->name = name;
116 /* Create a pool of things of size SIZE, with NUM in each block we
120 create_alloc_pool (const char *name, size_t size, size_t num)
123 size_t pool_size, header_size;
124 #ifdef GATHER_STATISTICS
125 struct alloc_pool_descriptor *desc;
130 /* Make size large enough to store the list header. */
131 if (size < sizeof (alloc_pool_list))
132 size = sizeof (alloc_pool_list);
134 /* Now align the size to a multiple of 4. */
135 size = align_eight (size);
137 #ifdef ENABLE_CHECKING
138 /* Add the aligned size of ID. */
139 size += offsetof (allocation_object, u.data);
142 /* Um, we can't really allocate 0 elements per block. */
145 /* Find the size of the pool structure, and the name. */
146 pool_size = sizeof (struct alloc_pool_def);
148 /* and allocate that much memory. */
149 pool = xmalloc (pool_size);
151 /* Now init the various pieces of our pool structure. */
152 pool->name = /*xstrdup (name)*/name;
153 #ifdef GATHER_STATISTICS
154 desc = alloc_pool_descriptor (name);
157 pool->elt_size = size;
158 pool->elts_per_block = num;
160 /* List header size should be a multiple of 8. */
161 header_size = align_eight (sizeof (struct alloc_pool_list_def));
163 pool->block_size = (size * num) + header_size;
164 pool->returned_free_list = NULL;
165 pool->virgin_free_list = NULL;
166 pool->virgin_elts_remaining = 0;
167 pool->elts_allocated = 0;
169 pool->blocks_allocated = 0;
170 pool->block_list = NULL;
172 #ifdef ENABLE_CHECKING
173 /* Increase the last used ID and use it for this pool.
174 ID == 0 is used for free elements of pool so skip it. */
185 /* Free all memory allocated for the given memory pool. */
187 free_alloc_pool (alloc_pool pool)
189 alloc_pool_list block, next_block;
190 #ifdef GATHER_STATISTICS
191 struct alloc_pool_descriptor *desc = alloc_pool_descriptor (pool->name);
196 /* Free each block allocated to the pool. */
197 for (block = pool->block_list; block != NULL; block = next_block)
199 next_block = block->next;
201 #ifdef GATHER_STATISTICS
202 desc->current -= pool->block_size;
205 #ifdef ENABLE_CHECKING
206 memset (pool, 0xaf, sizeof (*pool));
208 /* Lastly, free the pool. */
212 /* Frees the alloc_pool, if it is empty and zero *POOL in this case. */
214 free_alloc_pool_if_empty (alloc_pool *pool)
216 if ((*pool)->elts_free == (*pool)->elts_allocated)
218 free_alloc_pool (*pool);
223 /* Allocates one element from the pool specified. */
225 pool_alloc (alloc_pool pool)
227 alloc_pool_list header;
228 #ifdef GATHER_STATISTICS
229 struct alloc_pool_descriptor *desc = alloc_pool_descriptor (pool->name);
231 desc->allocated+=pool->elt_size;
236 /* If there are no more free elements, make some more!. */
237 if (!pool->returned_free_list)
240 if (!pool->virgin_elts_remaining)
242 alloc_pool_list block_header;
244 /* Make the block. */
245 block = XNEWVEC (char, pool->block_size);
246 block_header = (alloc_pool_list) block;
247 block += align_eight (sizeof (struct alloc_pool_list_def));
248 #ifdef GATHER_STATISTICS
249 desc->current += pool->block_size;
250 if (desc->peak < desc->current)
251 desc->peak = desc->current;
254 /* Throw it on the block list. */
255 block_header->next = pool->block_list;
256 pool->block_list = block_header;
258 /* Make the block available for allocation. */
259 pool->virgin_free_list = block;
260 pool->virgin_elts_remaining = pool->elts_per_block;
262 /* Also update the number of elements we have free/allocated, and
263 increment the allocated block count. */
264 pool->elts_allocated += pool->elts_per_block;
265 pool->elts_free += pool->elts_per_block;
266 pool->blocks_allocated += 1;
270 /* We now know that we can take the first elt off the virgin list and
271 put it on the returned list. */
272 block = pool->virgin_free_list;
273 header = (alloc_pool_list) USER_PTR_FROM_ALLOCATION_OBJECT_PTR (block);
275 #ifdef ENABLE_CHECKING
276 /* Mark the element to be free. */
277 ((allocation_object *) block)->id = 0;
279 pool->returned_free_list = header;
280 pool->virgin_free_list += pool->elt_size;
281 pool->virgin_elts_remaining--;
285 /* Pull the first free element from the free list, and return it. */
286 header = pool->returned_free_list;
287 pool->returned_free_list = header->next;
290 #ifdef ENABLE_CHECKING
291 /* Set the ID for element. */
292 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (header)->id = pool->id;
295 return ((void *) header);
298 /* Puts PTR back on POOL's free list. */
300 pool_free (alloc_pool pool, void *ptr)
302 alloc_pool_list header;
306 #ifdef ENABLE_CHECKING
307 /* Check whether the PTR was allocated from POOL. */
308 gcc_assert (pool->id == ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id);
310 memset (ptr, 0xaf, pool->elt_size - offsetof (allocation_object, u.data));
312 /* Mark the element to be free. */
313 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id = 0;
315 /* Check if we free more than we allocated, which is Bad (TM). */
316 gcc_assert (pool->elts_free < pool->elts_allocated);
319 header = (alloc_pool_list) ptr;
320 header->next = pool->returned_free_list;
321 pool->returned_free_list = header;
324 /* Output per-alloc_pool statistics. */
325 #ifdef GATHER_STATISTICS
327 /* Used to accumulate statistics about alloc_pool sizes. */
334 /* Called via htab_traverse. Output alloc_pool descriptor pointed out by SLOT
335 and update statistics. */
337 print_statistics (void **slot, void *b)
339 struct alloc_pool_descriptor *d = (struct alloc_pool_descriptor *) *slot;
340 struct output_info *i = (struct output_info *) b;
344 fprintf (stderr, "%-21s %6d %10d %10d %10d\n", d->name,
345 d->created, d->allocated, d->peak, d->current);
346 i->size += d->allocated;
347 i->count += d->created;
353 /* Output per-alloc_pool memory usage statistics. */
355 dump_alloc_pool_statistics (void)
357 #ifdef GATHER_STATISTICS
358 struct output_info info;
360 if (!alloc_pool_hash)
363 fprintf (stderr, "\nAlloc-pool Kind Pools Allocated Peak Leak\n");
364 fprintf (stderr, "-------------------------------------------------------------\n");
367 htab_traverse (alloc_pool_hash, print_statistics, &info);
368 fprintf (stderr, "-------------------------------------------------------------\n");
369 fprintf (stderr, "%-20s %7d %10d\n",
370 "Total", info.count, info.size);
371 fprintf (stderr, "-------------------------------------------------------------\n");