1 /* Functions to support a pool of allocatable objects.
2 Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2003
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, 59 Temple Place - Suite 330, Boston, MA
25 #include "alloc-pool.h"
27 /* Redefine abort to report an internal error w/o coredump, and
28 reporting the location of the error in the source file. This logic
29 is duplicated in rtl.h and tree.h because every file that needs the
30 special abort includes one or both. toplev.h gets too few files,
31 system.h gets too many. */
33 extern void fancy_abort PARAMS ((const char *, int, const char *))
35 #define abort() fancy_abort (__FILE__, __LINE__, __FUNCTION__)
37 #define align_four(x) (((x+3) >> 2) << 2)
38 #define align_eight(x) (((x+7) >> 3) << 3)
40 /* The internal allocation object. */
41 typedef struct allocation_object_def
43 #ifdef ENABLE_CHECKING
44 /* The ID of alloc pool which the object was allocated from. */
45 ALLOC_POOL_ID_TYPE id;
50 /* The data of the object. */
53 /* Because we want any type of data to be well aligned after the ID,
54 the following elements are here. They are never accessed so
55 the allocated object may be even smaller than this structure. */
58 HOST_WIDEST_INT align_i;
59 #ifdef HAVE_LONG_DOUBLE
65 /* Convert a pointer to allocation_object from a pointer to user data. */
66 #define ALLOCATION_OBJECT_PTR_FROM_USER_PTR(X) \
67 ((allocation_object *) (((char *) (X)) \
68 - offsetof (allocation_object, u.data)))
70 /* Convert a pointer to user data from a pointer to allocation_object. */
71 #define USER_PTR_FROM_ALLOCATION_OBJECT_PTR(X) \
72 ((void *) (((allocation_object *) (X))->u.data))
75 static ALLOC_POOL_ID_TYPE last_id;
77 /* Create a pool of things of size SIZE, with NUM in each block we
81 create_alloc_pool (name, size, num)
87 size_t pool_size, header_size;
92 /* Make size large enough to store the list header. */
93 if (size < sizeof (alloc_pool_list))
94 size = sizeof (alloc_pool_list);
96 /* Now align the size to a multiple of 4. */
97 size = align_four (size);
99 #ifdef ENABLE_CHECKING
100 /* Add the aligned size of ID. */
101 size += offsetof (allocation_object, u.data);
104 /* Um, we can't really allocate 0 elements per block. */
108 /* Find the size of the pool structure, and the name. */
109 pool_size = sizeof (struct alloc_pool_def);
111 /* and allocate that much memory. */
112 pool = (alloc_pool) xmalloc (pool_size);
114 /* Now init the various pieces of our pool structure. */
115 pool->name = xstrdup (name);
116 pool->elt_size = size;
117 pool->elts_per_block = num;
119 /* List header size should be a multiple of 8 */
120 header_size = align_eight (sizeof (struct alloc_pool_list_def));
122 pool->block_size = (size * num) + header_size;
123 pool->free_list = NULL;
124 pool->elts_allocated = 0;
126 pool->blocks_allocated = 0;
127 pool->block_list = NULL;
129 #ifdef ENABLE_CHECKING
130 /* Increase the last used ID and use it for this pool.
131 ID == 0 is used for free elements of pool so skip it. */
142 /* Free all memory allocated for the given memory pool. */
144 free_alloc_pool (pool)
147 alloc_pool_list block, next_block;
149 #ifdef ENABLE_CHECKING
154 /* Free each block allocated to the pool. */
155 for (block = pool->block_list; block != NULL; block = next_block)
157 next_block = block->next;
160 /* Lastly, free the pool and the name. */
165 /* Allocates one element from the pool specified. */
170 alloc_pool_list header;
173 #ifdef ENABLE_CHECKING
178 /* If there are no more free elements, make some more!. */
179 if (!pool->free_list)
182 alloc_pool_list block_header;
185 block = (char *) xmalloc (pool->block_size);
186 block_header = (alloc_pool_list) block;
187 block += align_eight (sizeof (struct alloc_pool_list_def));
189 /* Throw it on the block list */
190 block_header->next = pool->block_list;
191 pool->block_list = block_header;
193 /* Now put the actual block pieces onto the free list. */
194 for (i = 0; i < pool->elts_per_block; i++, block += pool->elt_size)
196 #ifdef ENABLE_CHECKING
197 /* Mark the element to be free. */
198 ((allocation_object *) block)->id = 0;
200 header = (alloc_pool_list) USER_PTR_FROM_ALLOCATION_OBJECT_PTR (block);
201 header->next = pool->free_list;
202 pool->free_list = header;
204 /* Also update the number of elements we have free/allocated, and
205 increment the allocated block count. */
206 pool->elts_allocated += pool->elts_per_block;
207 pool->elts_free += pool->elts_per_block;
208 pool->blocks_allocated += 1;
211 /* Pull the first free element from the free list, and return it. */
212 header = pool->free_list;
213 pool->free_list = header->next;
216 #ifdef ENABLE_CHECKING
217 /* Set the ID for element. */
218 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (header)->id = pool->id;
221 return ((void *) header);
224 /* Puts PTR back on POOL's free list. */
226 pool_free (pool, ptr)
230 alloc_pool_list header;
232 #ifdef ENABLE_CHECKING
236 /* Check whether the PTR was allocated from POOL. */
237 if (pool->id != ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id)
240 /* Mark the element to be free. */
241 ALLOCATION_OBJECT_PTR_FROM_USER_PTR (ptr)->id = 0;
243 /* Check if we free more than we allocated, which is Bad (TM). */
244 if (pool->elts_free + 1 > pool->elts_allocated)
248 header = (alloc_pool_list) ptr;
249 header->next = pool->free_list;
250 pool->free_list = header;