1/* Shared pool of memory blocks for pool allocators.
2 Copyright (C) 2015-2023 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along 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. */
27memory_block_pool memory_block_pool::instance;
28
29memory_block_pool::memory_block_pool () : m_blocks (NULL) {}
30
31/* Reduce free list to NUM blocks and return remaining to malloc. */
32void
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. */
60void *
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. */
70void
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 (uncast_block: chunk);
77 else
78 XDELETEVEC (chunk);
79}
80
81/* Return allocated memory back to malloc (and to system). */
82void
83memory_block_pool::trim (int num)
84{
85 instance.reduce_free_list (num);
86}
87

source code of gcc/memory-block.cc