heap/MarkStack.h

   1 /*
   2  * Copyright (C) 2009, 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef MarkStack_h
  27 #define MarkStack_h
  28
  29 #if ENABLE(OBJECT_MARK_LOGGING)
  30 #define MARK_LOG_MESSAGE0(message) dataLogF(message)
  31 #define MARK_LOG_MESSAGE1(message, arg1) dataLogF(message, arg1)
  32 #define MARK_LOG_MESSAGE2(message, arg1, arg2) dataLogF(message, arg1, arg2)
  33 #define MARK_LOG_ROOT(visitor, rootName) \
  34     dataLogF("\n%s: ", rootName); \
  35     (visitor).resetChildCount()
  36 #define MARK_LOG_PARENT(visitor, parent) \
  37     dataLogF("\n%p (%s): ", parent, parent->className() ? parent->className() : "unknown"); \
  38     (visitor).resetChildCount()
  39 #define MARK_LOG_CHILD(visitor, child) \
  40     if ((visitor).childCount()) \
  41     dataLogFString(", "); \
  42     dataLogF("%p", child); \
  43     (visitor).incrementChildCount()
  44 #else
  45 #define MARK_LOG_MESSAGE0(message) do { } while (false)
  46 #define MARK_LOG_MESSAGE1(message, arg1) do { } while (false)
  47 #define MARK_LOG_MESSAGE2(message, arg1, arg2) do { } while (false)
  48 #define MARK_LOG_ROOT(visitor, rootName) do { } while (false)
  49 #define MARK_LOG_PARENT(visitor, parent) do { } while (false)
  50 #define MARK_LOG_CHILD(visitor, child) do { } while (false)
  51 #endif
  52
  53 #include "HeapBlock.h"
  54 #include <wtf/StdLibExtras.h>
  55
  56 namespace JSC {
  57
  58 class BlockAllocator;
  59 class DeadBlock;
  60 class JSCell;
  61
  62 class MarkStackSegment : public HeapBlock<MarkStackSegment> {
  63 public:
  64     MarkStackSegment(Region* region)
  65         : HeapBlock<MarkStackSegment>(region)
  66 #if !ASSERT_DISABLED
  67         , m_top(0)
  68 #endif
  69     {
  70     }
  71
  72     static MarkStackSegment* create(DeadBlock*);
  73
  74     const JSCell** data()
  75     {
  76         return bitwise_cast<const JSCell**>(this + 1);
  77     }
  78
  79     static const size_t blockSize = 4 * KB;
  80
  81 #if !ASSERT_DISABLED
  82     size_t m_top;
  83 #endif
  84 };
  85
  86 class MarkStackArray {
  87 public:
  88     MarkStackArray(BlockAllocator&);
  89     ~MarkStackArray();
  90
  91     void append(const JSCell*);
  92
  93     bool canRemoveLast();
  94     const JSCell* removeLast();
  95     bool refill();
  96
  97     void donateSomeCellsTo(MarkStackArray& other);
  98     void stealSomeCellsFrom(MarkStackArray& other, size_t idleThreadCount);
  99
 100     size_t size();
 101     bool isEmpty();
 102
 103 private:
 104     template <size_t size> struct CapacityFromSize {
 105         static const size_t value = (size - sizeof(MarkStackSegment)) / sizeof(const JSCell*);
 106     };
 107
 108     JS_EXPORT_PRIVATE void expand();
 109
 110     size_t postIncTop();
 111     size_t preDecTop();
 112     void setTopForFullSegment();
 113     void setTopForEmptySegment();
 114     size_t top();
 115
 116     void validatePrevious();
 117
 118     DoublyLinkedList<MarkStackSegment> m_segments;
 119     BlockAllocator& m_blockAllocator;
 120
 121     JS_EXPORT_PRIVATE static const size_t s_segmentCapacity = CapacityFromSize<MarkStackSegment::blockSize>::value;
 122     size_t m_top;
 123     size_t m_numberOfSegments;
 124
 125 };
 126
 127 } // namespace JSC
 128
 129 #endif