1/*
2 * Copyright (C) 2011 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "ConservativeRoots.h"
28
29#include "CodeBlock.h"
30#include "CopiedSpace.h"
31#include "CopiedSpaceInlines.h"
32#include "DFGCodeBlocks.h"
33#include "JSCell.h"
34#include "JSObject.h"
35#include "Structure.h"
36
37namespace JSC {
38
39ConservativeRoots::ConservativeRoots(const MarkedBlockSet* blocks, CopiedSpace* copiedSpace)
40    : m_roots(m_inlineRoots)
41    , m_size(0)
42    , m_capacity(inlineCapacity)
43    , m_blocks(blocks)
44    , m_copiedSpace(copiedSpace)
45{
46}
47
48ConservativeRoots::~ConservativeRoots()
49{
50    if (m_roots != m_inlineRoots)
51        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
52}
53
54void ConservativeRoots::grow()
55{
56    size_t newCapacity = m_capacity == inlineCapacity ? nonInlineCapacity : m_capacity * 2;
57    JSCell** newRoots = static_cast<JSCell**>(OSAllocator::reserveAndCommit(newCapacity * sizeof(JSCell*)));
58    memcpy(newRoots, m_roots, m_size * sizeof(JSCell*));
59    if (m_roots != m_inlineRoots)
60        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
61    m_capacity = newCapacity;
62    m_roots = newRoots;
63}
64
65template<typename MarkHook>
66inline void ConservativeRoots::genericAddPointer(void* p, TinyBloomFilter filter, MarkHook& markHook)
67{
68    markHook.mark(p);
69
70    m_copiedSpace->pinIfNecessary(p);
71
72    MarkedBlock* candidate = MarkedBlock::blockFor(p);
73    if (filter.ruleOut(reinterpret_cast<Bits>(candidate))) {
74        ASSERT(!candidate || !m_blocks->set().contains(candidate));
75        return;
76    }
77
78    if (!MarkedBlock::isAtomAligned(p))
79        return;
80
81    if (!m_blocks->set().contains(candidate))
82        return;
83
84    if (!candidate->isLiveCell(p))
85        return;
86
87    if (m_size == m_capacity)
88        grow();
89
90    m_roots[m_size++] = static_cast<JSCell*>(p);
91}
92
93template<typename MarkHook>
94void ConservativeRoots::genericAddSpan(void* begin, void* end, MarkHook& markHook)
95{
96    ASSERT(begin <= end);
97    ASSERT((static_cast<char*>(end) - static_cast<char*>(begin)) < 0x1000000);
98    ASSERT(isPointerAligned(begin));
99    ASSERT(isPointerAligned(end));
100
101    TinyBloomFilter filter = m_blocks->filter(); // Make a local copy of filter to show the compiler it won't alias, and can be register-allocated.
102    for (char** it = static_cast<char**>(begin); it != static_cast<char**>(end); ++it)
103        genericAddPointer(*it, filter, markHook);
104}
105
106class DummyMarkHook {
107public:
108    void mark(void*) { }
109};
110
111void ConservativeRoots::add(void* begin, void* end)
112{
113    DummyMarkHook dummy;
114    genericAddSpan(begin, end, dummy);
115}
116
117void ConservativeRoots::add(void* begin, void* end, JITStubRoutineSet& jitStubRoutines)
118{
119    genericAddSpan(begin, end, jitStubRoutines);
120}
121
122template<typename T, typename U>
123class CompositeMarkHook {
124public:
125    CompositeMarkHook(T& first, U& second)
126        : m_first(first)
127        , m_second(second)
128    {
129    }
130
131    void mark(void* address)
132    {
133        m_first.mark(address);
134        m_second.mark(address);
135    }
136
137private:
138    T& m_first;
139    U& m_second;
140};
141
142void ConservativeRoots::add(
143    void* begin, void* end, JITStubRoutineSet& jitStubRoutines, DFGCodeBlocks& dfgCodeBlocks)
144{
145    CompositeMarkHook<JITStubRoutineSet, DFGCodeBlocks> markHook(
146        jitStubRoutines, dfgCodeBlocks);
147    genericAddSpan(begin, end, markHook);
148}
149
150} // namespace JSC
151