heap/CopyVisitor.h

   1 /*
   2  * Copyright (C) 2012 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 CopyVisitor_h
  27 #define CopyVisitor_h
  28
  29 #include "CopiedSpace.h"
  30
  31 namespace JSC {
  32
  33 class GCThreadSharedData;
  34 class JSCell;
  35
  36 class CopyVisitor {
  37 public:
  38     CopyVisitor(GCThreadSharedData&);
  39
  40     void copyFromShared();
  41
  42     void startCopying();
  43     void doneCopying();
  44
  45     // Low-level API for copying, appropriate for cases where the object's heap references
  46     // are discontiguous or if the object occurs frequently enough that you need to focus on
  47     // performance. Use this with care as it is easy to shoot yourself in the foot.
  48     bool checkIfShouldCopy(void*);
  49     void* allocateNewSpace(size_t);
  50     void didCopy(void*, size_t);
  51
  52 private:
  53     void* allocateNewSpaceSlow(size_t);
  54     void visitCell(JSCell*);
  55
  56     GCThreadSharedData& m_shared;
  57     CopiedAllocator m_copiedAllocator;
  58 };
  59
  60 } // namespace JSC
  61
  62 #endif