heap/ConservativeRoots.cpp

   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
  37 namespace JSC {
  38
  39 ConservativeRoots::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
  48 ConservativeRoots::~ConservativeRoots()
  49 {
  50     if (m_roots != m_inlineRoots)
  51         OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
  52 }
  53
  54 void 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
  65 template<typename MarkHook>
  66 inline 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
  93 template<typename MarkHook>
  94 void 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
 106 class DummyMarkHook {
 107 public:
 108     void mark(void*) { }
 109 };
 110
 111 void ConservativeRoots::add(void* begin, void* end)
 112 {
 113     DummyMarkHook dummy;
 114     genericAddSpan(begin, end, dummy);
 115 }
 116
 117 void ConservativeRoots::add(void* begin, void* end, JITStubRoutineSet& jitStubRoutines)
 118 {
 119     genericAddSpan(begin, end, jitStubRoutines);
 120 }
 121
 122 template<typename T, typename U>
 123 class CompositeMarkHook {
 124 public:
 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
 137 private:
 138     T& m_first;
 139     U& m_second;
 140 };
 141
 142 void 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