1 /* Shared pool of memory blocks for pool allocators. 2 Copyright (C) 2015-2018 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 */ 77