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comparison gcc/alloc-pool.c @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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-1:000000000000 0:a06113de4d67
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 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 char *align_p;
46 HOST_WIDEST_INT align_i;
47 long double align_ld;
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 1);
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_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_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_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_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 gcc_assert (ptr);
332
333 #ifdef ENABLE_CHECKING
334 /* Check whether the PTR was allocated from POOL. */
335 gcc_assert (pool->id == ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id);
336
337 memset (ptr, 0xaf, pool->elt_size - offsetof (allocation_object, u.data));
338
339 /* Mark the element to be free. */
340 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id = 0;
341 #else
342 /* Check if we free more than we allocated, which is Bad (TM). */
343 gcc_assert (pool->elts_free < pool->elts_allocated);
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 }