heap/WriteBarrierBuffer.h

   1 /*
   2  * Copyright (C) 2013 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 WriteBarrierBuffer_h
  27 #define WriteBarrierBuffer_h
  28
  29 #include <wtf/FastMalloc.h>
  30
  31 namespace JSC {
  32
  33 class Heap;
  34 class JSCell;
  35
  36 namespace FTL { class LowerDFGToLLVM; }
  37
  38 class WriteBarrierBuffer {
  39     friend class FTL::LowerDFGToLLVM;
  40 public:
  41     WriteBarrierBuffer(unsigned capacity);
  42     ~WriteBarrierBuffer();
  43
  44     void add(JSCell*);
  45     void flush(Heap&);
  46     void reset();
  47
  48     static ptrdiff_t currentIndexOffset()
  49     {
  50         return OBJECT_OFFSETOF(WriteBarrierBuffer, m_currentIndex);
  51     }
  52
  53     static ptrdiff_t capacityOffset()
  54     {
  55         return OBJECT_OFFSETOF(WriteBarrierBuffer, m_capacity);
  56     }
  57
  58     static ptrdiff_t bufferOffset()
  59     {
  60         return OBJECT_OFFSETOF(WriteBarrierBuffer, m_buffer);
  61     }
  62
  63 private:
  64     unsigned m_currentIndex;
  65     unsigned m_capacity;
  66     JSCell** m_buffer;
  67 };
  68
  69 } // namespace JSC
  70
  71 #endif // WriteBarrierBuffer_h