heap/HandleSet.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 "HandleSet.h"
  28
  29 #include "HandleBlock.h"
  30 #include "HandleBlockInlines.h"
  31 #include "HeapRootVisitor.h"
  32 #include "JSObject.h"
  33 #include "JSCInlines.h"
  34 #include <wtf/DataLog.h>
  35
  36 namespace JSC {
  37
  38 HandleSet::HandleSet(VM* vm)
  39     : m_vm(vm)
  40 {
  41     grow();
  42 }
  43
  44 HandleSet::~HandleSet()
  45 {
  46     while (!m_blockList.isEmpty())
  47         m_vm->heap.blockAllocator().deallocate(HandleBlock::destroy(m_blockList.removeHead()));
  48 }
  49
  50 void HandleSet::grow()
  51 {
  52     HandleBlock* newBlock = HandleBlock::create(m_vm->heap.blockAllocator().allocate<HandleBlock>(), this);
  53     m_blockList.append(newBlock);
  54
  55     for (int i = newBlock->nodeCapacity() - 1; i >= 0; --i) {
  56         Node* node = newBlock->nodeAtIndex(i);
  57         new (NotNull, node) Node;
  58         m_freeList.push(node);
  59     }
  60 }
  61
  62 void HandleSet::visitStrongHandles(HeapRootVisitor& heapRootVisitor)
  63 {
  64     Node* end = m_strongList.end();
  65     for (Node* node = m_strongList.begin(); node != end; node = node->next()) {
  66 #if ENABLE(GC_VALIDATION)
  67         RELEASE_ASSERT(isLiveNode(node));
  68 #endif
  69         heapRootVisitor.visit(node->slot());
  70     }
  71 }
  72
  73 void HandleSet::writeBarrier(HandleSlot slot, const JSValue& value)
  74 {
  75     if (!value == !*slot && slot->isCell() == value.isCell())
  76         return;
  77
  78     Node* node = toNode(slot);
  79 #if ENABLE(GC_VALIDATION)
  80     RELEASE_ASSERT(isLiveNode(node));
  81 #endif
  82     SentinelLinkedList<Node>::remove(node);
  83     if (!value || !value.isCell()) {
  84         m_immediateList.push(node);
  85         return;
  86     }
  87
  88     m_strongList.push(node);
  89 #if ENABLE(GC_VALIDATION)
  90     RELEASE_ASSERT(isLiveNode(node));
  91 #endif
  92 }
  93
  94 unsigned HandleSet::protectedGlobalObjectCount()
  95 {
  96     unsigned count = 0;
  97     Node* end = m_strongList.end();
  98     for (Node* node = m_strongList.begin(); node != end; node = node->next()) {
  99         JSValue value = *node->slot();
 100         if (value.isObject() && asObject(value.asCell())->isGlobalObject())
 101             count++;
 102     }
 103     return count;
 104 }
 105
 106 #if ENABLE(GC_VALIDATION) || !ASSERT_DISABLED
 107 bool HandleSet::isLiveNode(Node* node)
 108 {
 109     if (node->prev()->next() != node)
 110         return false;
 111     if (node->next()->prev() != node)
 112         return false;
 113
 114     return true;
 115 }
 116 #endif
 117
 118 } // namespace JSC