1 /*
2 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
3 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 */
20
21 #include "config.h"
22 #include "MarkedSpace.h"
23
24 #include "JSCell.h"
25 #include "JSGlobalData.h"
26 #include "JSLock.h"
27 #include "JSObject.h"
28 #include "ScopeChain.h"
29
30 namespace JSC {
31
32 class Structure;
33
MarkedSpace(JSGlobalData * globalData)34 MarkedSpace::MarkedSpace(JSGlobalData* globalData)
35 : m_waterMark(0)
36 , m_highWaterMark(0)
37 , m_globalData(globalData)
38 {
39 for (size_t cellSize = preciseStep; cellSize < preciseCutoff; cellSize += preciseStep)
40 sizeClassFor(cellSize).cellSize = cellSize;
41
42 for (size_t cellSize = impreciseStep; cellSize < impreciseCutoff; cellSize += impreciseStep)
43 sizeClassFor(cellSize).cellSize = cellSize;
44 }
45
destroy()46 void MarkedSpace::destroy()
47 {
48 clearMarks();
49 shrink();
50 ASSERT(!size());
51 }
52
allocateBlock(SizeClass & sizeClass)53 MarkedBlock* MarkedSpace::allocateBlock(SizeClass& sizeClass)
54 {
55 MarkedBlock* block = MarkedBlock::create(globalData(), sizeClass.cellSize);
56 sizeClass.blockList.append(block);
57 sizeClass.nextBlock = block;
58 m_blocks.add(block);
59
60 return block;
61 }
62
freeBlocks(DoublyLinkedList<MarkedBlock> & blocks)63 void MarkedSpace::freeBlocks(DoublyLinkedList<MarkedBlock>& blocks)
64 {
65 MarkedBlock* next;
66 for (MarkedBlock* block = blocks.head(); block; block = next) {
67 next = block->next();
68
69 blocks.remove(block);
70 m_blocks.remove(block);
71 MarkedBlock::destroy(block);
72 }
73 }
74
allocateFromSizeClass(SizeClass & sizeClass)75 void* MarkedSpace::allocateFromSizeClass(SizeClass& sizeClass)
76 {
77 for (MarkedBlock*& block = sizeClass.nextBlock ; block; block = block->next()) {
78 if (void* result = block->allocate())
79 return result;
80
81 m_waterMark += block->capacity();
82 }
83
84 if (m_waterMark < m_highWaterMark)
85 return allocateBlock(sizeClass)->allocate();
86
87 return 0;
88 }
89
shrink()90 void MarkedSpace::shrink()
91 {
92 // We record a temporary list of empties to avoid modifying m_blocks while iterating it.
93 DoublyLinkedList<MarkedBlock> empties;
94
95 BlockIterator end = m_blocks.end();
96 for (BlockIterator it = m_blocks.begin(); it != end; ++it) {
97 MarkedBlock* block = *it;
98 if (block->isEmpty()) {
99 SizeClass& sizeClass = sizeClassFor(block->cellSize());
100 sizeClass.blockList.remove(block);
101 sizeClass.nextBlock = sizeClass.blockList.head();
102 empties.append(block);
103 }
104 }
105
106 freeBlocks(empties);
107 ASSERT(empties.isEmpty());
108 }
109
clearMarks()110 void MarkedSpace::clearMarks()
111 {
112 BlockIterator end = m_blocks.end();
113 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
114 (*it)->clearMarks();
115 }
116
sweep()117 void MarkedSpace::sweep()
118 {
119 BlockIterator end = m_blocks.end();
120 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
121 (*it)->sweep();
122 }
123
objectCount() const124 size_t MarkedSpace::objectCount() const
125 {
126 size_t result = 0;
127 BlockIterator end = m_blocks.end();
128 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
129 result += (*it)->markCount();
130 return result;
131 }
132
size() const133 size_t MarkedSpace::size() const
134 {
135 size_t result = 0;
136 BlockIterator end = m_blocks.end();
137 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
138 result += (*it)->size();
139 return result;
140 }
141
capacity() const142 size_t MarkedSpace::capacity() const
143 {
144 size_t result = 0;
145 BlockIterator end = m_blocks.end();
146 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
147 result += (*it)->capacity();
148 return result;
149 }
150
reset()151 void MarkedSpace::reset()
152 {
153 m_waterMark = 0;
154
155 for (size_t cellSize = preciseStep; cellSize < preciseCutoff; cellSize += preciseStep)
156 sizeClassFor(cellSize).reset();
157
158 for (size_t cellSize = impreciseStep; cellSize < impreciseCutoff; cellSize += impreciseStep)
159 sizeClassFor(cellSize).reset();
160
161 BlockIterator end = m_blocks.end();
162 for (BlockIterator it = m_blocks.begin(); it != end; ++it)
163 (*it)->reset();
164 }
165
166 } // namespace JSC
167