heap/SlotVisitor.h

   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 #ifndef SlotVisitor_h
  27 #define SlotVisitor_h
  28
  29 #include "CopiedSpace.h"
  30 #include "MarkStack.h"
  31
  32 namespace JSC {
  33
  34 class Heap;
  35
  36 class SlotVisitor : public MarkStack {
  37     friend class HeapRootVisitor;
  38 public:
  39     SlotVisitor(MarkStackThreadSharedData&);
  40
  41     void donate()
  42     {
  43         ASSERT(m_isInParallelMode);
  44         if (Options::numberOfGCMarkers == 1)
  45             return;
  46
  47         donateKnownParallel();
  48     }
  49
  50     void drain();
  51
  52     void donateAndDrain()
  53     {
  54         donate();
  55         drain();
  56     }
  57
  58     enum SharedDrainMode { SlaveDrain, MasterDrain };
  59     void drainFromShared(SharedDrainMode);
  60
  61     void harvestWeakReferences();
  62     void finalizeUnconditionalFinalizers();
  63
  64     void startCopying();
  65     void copyAndAppend(void**, size_t, JSValue*, unsigned);
  66     void doneCopying();
  67
  68 private:
  69     void* allocateNewSpace(void*, size_t);
  70
  71     void donateSlow();
  72
  73     void donateKnownParallel()
  74     {
  75         if (!m_stack.canDonateSomeCells())
  76             return;
  77         donateSlow();
  78     }
  79
  80     CopiedBlock* m_copyBlock;
  81 };
  82
  83 inline SlotVisitor::SlotVisitor(MarkStackThreadSharedData& shared)
  84     : MarkStack(shared)
  85     , m_copyBlock(0)
  86 {
  87 }
  88
  89 } // namespace JSC
  90
  91 #endif // SlotVisitor_h