1 /* Shared pool of memory blocks for pool allocators. 2 Copyright (C) 2015-2020 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 it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 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 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "memory-block.h" 24 #include "obstack.h" 25 26 /* Global singleton-like instance. */ 27 memory_block_pool memory_block_pool::instance; 28 memory_block_pool()29memory_block_pool::memory_block_pool () : m_blocks (NULL) {} 30 31 /* Reduce free list to NUM blocks and return remaining to malloc. */ 32 void reduce_free_list(int num)33memory_block_pool::reduce_free_list (int num) 34 { 35 block_list **blocks = &m_blocks; 36 37 /* First skip NUM blocks. */ 38 39 for (;num > 0 && *blocks; num--) 40 blocks = &(*blocks)->m_next; 41 42 if (!*blocks) 43 return; 44 45 /* And free the remainder of them. */ 46 47 block_list *to_free = *blocks; 48 *blocks = NULL; 49 50 while (to_free) 51 { 52 block_list *next = to_free->m_next; 53 XDELETEVEC (to_free); 54 to_free = next; 55 } 56 } 57 58 /* Allocate a chunk for obstack. Use the pool if requested chunk size matches 59 the size of blocks in the pool. */ 60 void * mempool_obstack_chunk_alloc(size_t size)61mempool_obstack_chunk_alloc (size_t size) 62 { 63 if (size == memory_block_pool::block_size) 64 return memory_block_pool::allocate (); 65 else 66 return XNEWVEC (char, size); 67 } 68 69 /* Free previously allocated obstack chunk. */ 70 void mempool_obstack_chunk_free(void * chunk)71mempool_obstack_chunk_free (void *chunk) 72 { 73 size_t size = (reinterpret_cast<_obstack_chunk *> (chunk)->limit 74 - reinterpret_cast<char *> (chunk)); 75 if (size == memory_block_pool::block_size) 76 memory_block_pool::release (chunk); 77 else 78 XDELETEVEC (chunk); 79 } 80 81 /* Return allocated memory back to malloc (and to system). */ 82 void trim(int num)83memory_block_pool::trim (int num) 84 { 85 instance.reduce_free_list (num); 86 } 87