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 "CodeBlockSet.h"
31#include "CopiedSpace.h"
32#include "CopiedSpaceInlines.h"
33#include "JSCell.h"
34#include "JSObject.h"
35#include "JSCInlines.h"
36#include "Structure.h"
37
38namespace JSC {
39
40ConservativeRoots::ConservativeRoots(const MarkedBlockSet* blocks, CopiedSpace* copiedSpace)
41    : m_roots(m_inlineRoots)
42    , m_size(0)
43    , m_capacity(inlineCapacity)
44    , m_blocks(blocks)
45    , m_copiedSpace(copiedSpace)
46{
47}
48
49ConservativeRoots::~ConservativeRoots()
50{
51    if (m_roots != m_inlineRoots)
52        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
53}
54
55void ConservativeRoots::grow()
56{
57    size_t newCapacity = m_capacity == inlineCapacity ? nonInlineCapacity : m_capacity * 2;
58    JSCell** newRoots = static_cast<JSCell**>(OSAllocator::reserveAndCommit(newCapacity * sizeof(JSCell*)));
59    memcpy(newRoots, m_roots, m_size * sizeof(JSCell*));
60    if (m_roots != m_inlineRoots)
61        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
62    m_capacity = newCapacity;
63    m_roots = newRoots;
64}
65
66template<typename MarkHook>
67inline void ConservativeRoots::genericAddPointer(void* p, TinyBloomFilter filter, MarkHook& markHook)
68{
69    markHook.mark(p);
70
71    m_copiedSpace->pinIfNecessary(p);
72
73    MarkedBlock* candidate = MarkedBlock::blockFor(p);
74    if (filter.ruleOut(reinterpret_cast<Bits>(candidate))) {
75        ASSERT(!candidate || !m_blocks->set().contains(candidate));
76        return;
77    }
78
79    if (!MarkedBlock::isAtomAligned(p))
80        return;
81
82    if (!m_blocks->set().contains(candidate))
83        return;
84
85    if (!candidate->isLiveCell(p))
86        return;
87
88    if (m_size == m_capacity)
89        grow();
90
91    m_roots[m_size++] = static_cast<JSCell*>(p);
92}
93
94template<typename MarkHook>
95void ConservativeRoots::genericAddSpan(void* begin, void* end, MarkHook& markHook)
96{
97    if (begin > end) {
98        void* swapTemp = begin;
99        begin = end;
100        end = swapTemp;
101    }
102
103    RELEASE_ASSERT(isPointerAligned(begin));
104    RELEASE_ASSERT(isPointerAligned(end));
105
106    TinyBloomFilter filter = m_blocks->filter(); // Make a local copy of filter to show the compiler it won't alias, and can be register-allocated.
107    for (char** it = static_cast<char**>(begin); it != static_cast<char**>(end); ++it)
108        genericAddPointer(*it, filter, markHook);
109}
110
111class DummyMarkHook {
112public:
113    void mark(void*) { }
114};
115
116void ConservativeRoots::add(void* begin, void* end)
117{
118    DummyMarkHook dummy;
119    genericAddSpan(begin, end, dummy);
120}
121
122void ConservativeRoots::add(void* begin, void* end, JITStubRoutineSet& jitStubRoutines)
123{
124    genericAddSpan(begin, end, jitStubRoutines);
125}
126
127template<typename T, typename U>
128class CompositeMarkHook {
129public:
130    CompositeMarkHook(T& first, U& second)
131        : m_first(first)
132        , m_second(second)
133    {
134    }
135
136    void mark(void* address)
137    {
138        m_first.mark(address);
139        m_second.mark(address);
140    }
141
142private:
143    T& m_first;
144    U& m_second;
145};
146
147void ConservativeRoots::add(
148    void* begin, void* end, JITStubRoutineSet& jitStubRoutines, CodeBlockSet& codeBlocks)
149{
150    CompositeMarkHook<JITStubRoutineSet, CodeBlockSet> markHook(jitStubRoutines, codeBlocks);
151    genericAddSpan(begin, end, markHook);
152}
153
154} // namespace JSC
155