xref: /dflybsd-src/contrib/gcc-8.0/gcc/memory-block.h (revision 38fd149817dfbff97799f62fcb70be98c4e32523)
1*38fd1498Szrj /* Shared pool of memory blocks for pool allocators.
2*38fd1498Szrj    Copyright (C) 2015-2018 Free Software Foundation, Inc.
3*38fd1498Szrj 
4*38fd1498Szrj This file is part of GCC.
5*38fd1498Szrj 
6*38fd1498Szrj GCC is free software; you can redistribute it and/or modify
7*38fd1498Szrj it under the terms of the GNU General Public License as published by
8*38fd1498Szrj the Free Software Foundation; either version 3, or (at your option)
9*38fd1498Szrj any later version.
10*38fd1498Szrj 
11*38fd1498Szrj GCC is distributed in the hope that it will be useful,
12*38fd1498Szrj but WITHOUT ANY WARRANTY; without even the implied warranty of
13*38fd1498Szrj MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14*38fd1498Szrj GNU General Public License for more details.
15*38fd1498Szrj 
16*38fd1498Szrj You should have received a copy of the GNU General Public License
17*38fd1498Szrj along with GCC; see the file COPYING3.  If not see
18*38fd1498Szrj <http://www.gnu.org/licenses/>.  */
19*38fd1498Szrj 
20*38fd1498Szrj 
21*38fd1498Szrj #ifndef MEMORY_BLOCK_H
22*38fd1498Szrj #define MEMORY_BLOCK_H
23*38fd1498Szrj 
24*38fd1498Szrj /* Shared pool which allows other memory pools to reuse each others' allocated
25*38fd1498Szrj    memory blocks instead of calling free/malloc again.  */
26*38fd1498Szrj class memory_block_pool
27*38fd1498Szrj {
28*38fd1498Szrj public:
29*38fd1498Szrj   /* Blocks have fixed size.  This is necessary for sharing.  */
30*38fd1498Szrj   static const size_t block_size = 64 * 1024;
31*38fd1498Szrj 
32*38fd1498Szrj   memory_block_pool ();
33*38fd1498Szrj 
34*38fd1498Szrj   static inline void *allocate () ATTRIBUTE_MALLOC;
35*38fd1498Szrj   static inline void release (void *);
36*38fd1498Szrj   void clear_free_list ();
37*38fd1498Szrj 
38*38fd1498Szrj private:
39*38fd1498Szrj   /* memory_block_pool singleton instance, defined in memory-block.cc.  */
40*38fd1498Szrj   static memory_block_pool instance;
41*38fd1498Szrj 
42*38fd1498Szrj   struct block_list
43*38fd1498Szrj   {
44*38fd1498Szrj     block_list *m_next;
45*38fd1498Szrj   };
46*38fd1498Szrj 
47*38fd1498Szrj   /* Free list.  */
48*38fd1498Szrj   block_list *m_blocks;
49*38fd1498Szrj };
50*38fd1498Szrj 
51*38fd1498Szrj /* Allocate a single block.  Reuse a previously returned block, if possible.  */
52*38fd1498Szrj inline void *
allocate()53*38fd1498Szrj memory_block_pool::allocate ()
54*38fd1498Szrj {
55*38fd1498Szrj   if (instance.m_blocks == NULL)
56*38fd1498Szrj     return XNEWVEC (char, block_size);
57*38fd1498Szrj 
58*38fd1498Szrj   void *result = instance.m_blocks;
59*38fd1498Szrj   instance.m_blocks = instance.m_blocks->m_next;
60*38fd1498Szrj   VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, block_size));
61*38fd1498Szrj   return result;
62*38fd1498Szrj }
63*38fd1498Szrj 
64*38fd1498Szrj /* Return UNCAST_BLOCK to the pool.  */
65*38fd1498Szrj inline void
release(void * uncast_block)66*38fd1498Szrj memory_block_pool::release (void *uncast_block)
67*38fd1498Szrj {
68*38fd1498Szrj   block_list *block = new (uncast_block) block_list;
69*38fd1498Szrj   block->m_next = instance.m_blocks;
70*38fd1498Szrj   instance.m_blocks = block;
71*38fd1498Szrj }
72*38fd1498Szrj 
73*38fd1498Szrj extern void *mempool_obstack_chunk_alloc (size_t) ATTRIBUTE_MALLOC;
74*38fd1498Szrj extern void mempool_obstack_chunk_free (void *);
75*38fd1498Szrj 
76*38fd1498Szrj #endif /* MEMORY_BLOCK_H */
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