comparison gcc/memory-block.h @ 16:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents
children 84e7813d76e9
comparison
equal deleted inserted replaced
15:561a7518be6b 16:04ced10e8804
1 /* Shared pool of memory blocks for pool allocators.
2 Copyright (C) 2015-2017 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20
21 #ifndef MEMORY_BLOCK_H
22 #define MEMORY_BLOCK_H
23
24 /* Shared pool which allows other memory pools to reuse each others' allocated
25 memory blocks instead of calling free/malloc again. */
26 class memory_block_pool
27 {
28 public:
29 /* Blocks have fixed size. This is necessary for sharing. */
30 static const size_t block_size = 64 * 1024;
31
32 memory_block_pool ();
33
34 static inline void *allocate () ATTRIBUTE_MALLOC;
35 static inline void release (void *);
36 void clear_free_list ();
37
38 private:
39 /* memory_block_pool singleton instance, defined in memory-block.cc. */
40 static memory_block_pool instance;
41
42 struct block_list
43 {
44 block_list *m_next;
45 };
46
47 /* Free list. */
48 block_list *m_blocks;
49 };
50
51 /* Allocate a single block. Reuse a previously returned block, if possible. */
52 inline void *
53 memory_block_pool::allocate ()
54 {
55 if (instance.m_blocks == NULL)
56 return XNEWVEC (char, block_size);
57
58 void *result = instance.m_blocks;
59 instance.m_blocks = instance.m_blocks->m_next;
60 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, block_size));
61 return result;
62 }
63
64 /* Return UNCAST_BLOCK to the pool. */
65 inline void
66 memory_block_pool::release (void *uncast_block)
67 {
68 block_list *block = new (uncast_block) block_list;
69 block->m_next = instance.m_blocks;
70 instance.m_blocks = block;
71 }
72
73 extern void *mempool_obstack_chunk_alloc (size_t) ATTRIBUTE_MALLOC;
74 extern void mempool_obstack_chunk_free (void *);
75
76 #endif /* MEMORY_BLOCK_H */