| 1 | /* Shared pool of memory blocks for pool allocators. |
|---|
| 2 | Copyright (C) 2015-2023 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 | /* Number of blocks we keep in the freelists. */ |
|---|
| 32 | static const size_t freelist_size = 1024 * 1024 / block_size; |
|---|
| 33 | |
|---|
| 34 | memory_block_pool (); |
|---|
| 35 | |
|---|
| 36 | static inline void *allocate () ATTRIBUTE_MALLOC; |
|---|
| 37 | static inline void release (void *); |
|---|
| 38 | static void trim (int nblocks = freelist_size); |
|---|
| 39 | void reduce_free_list (int); |
|---|
| 40 | |
|---|
| 41 | private: |
|---|
| 42 | /* memory_block_pool singleton instance, defined in memory-block.cc. */ |
|---|
| 43 | static memory_block_pool instance; |
|---|
| 44 | |
|---|
| 45 | struct block_list |
|---|
| 46 | { |
|---|
| 47 | block_list *m_next; |
|---|
| 48 | }; |
|---|
| 49 | |
|---|
| 50 | /* Free list. */ |
|---|
| 51 | block_list *m_blocks; |
|---|
| 52 | }; |
|---|
| 53 | |
|---|
| 54 | /* Allocate a single block. Reuse a previously returned block, if possible. */ |
|---|
| 55 | inline void * |
|---|
| 56 | memory_block_pool::allocate () |
|---|
| 57 | { |
|---|
| 58 | if (instance.m_blocks == NULL) |
|---|
| 59 | return XNEWVEC (char, block_size); |
|---|
| 60 | |
|---|
| 61 | void *result = instance.m_blocks; |
|---|
| 62 | instance.m_blocks = instance.m_blocks->m_next; |
|---|
| 63 | VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, block_size)); |
|---|
| 64 | return result; |
|---|
| 65 | } |
|---|
| 66 | |
|---|
| 67 | /* Return UNCAST_BLOCK to the pool. */ |
|---|
| 68 | inline void |
|---|
| 69 | memory_block_pool::release (void *uncast_block) |
|---|
| 70 | { |
|---|
| 71 | block_list *block = new (uncast_block) block_list; |
|---|
| 72 | block->m_next = instance.m_blocks; |
|---|
| 73 | instance.m_blocks = block; |
|---|
| 74 | |
|---|
| 75 | VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS ((char *)uncast_block |
|---|
| 76 | + sizeof (block_list), |
|---|
| 77 | block_size |
|---|
| 78 | - sizeof (block_list))); |
|---|
| 79 | } |
|---|
| 80 | |
|---|
| 81 | extern void *mempool_obstack_chunk_alloc (size_t) ATTRIBUTE_MALLOC; |
|---|
| 82 | extern void mempool_obstack_chunk_free (void *); |
|---|
| 83 | |
|---|
| 84 | #endif /* MEMORY_BLOCK_H */ |
|---|
| 85 | |
|---|
