Source/JavaScriptCore/bytecode/FullBytecodeLiveness.h

/*
 * Copyright (C) 2013, 2015 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#pragma once

#include <wtf/FastBitVector.h>

namespace JSC {

class BytecodeLivenessAnalysis;

typedef HashMap<BytecodeIndex, FastBitVector> BytecodeToBitmapMap;

class FullBytecodeLiveness {
    WTF_MAKE_FAST_ALLOCATED;
public:
    const FastBitVector& getLiveness(BytecodeIndex bytecodeIndex) const
    {
        // FIXME: What should this do when we have checkpoints?
        return m_map[bytecodeIndex.offset()];
    }
    
    bool operandIsLive(int operand, BytecodeIndex bytecodeIndex) const
    {
        return operandIsAlwaysLive(operand) || operandThatIsNotAlwaysLiveIsLive(getLiveness(bytecodeIndex), operand);
    }
    
private:
    friend class BytecodeLivenessAnalysis;
    
    Vector<FastBitVector, 0, UnsafeVectorOverflow> m_map;
};

} // namespace JSC