Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.h

/*
 * Copyright (C) 2013, 2015 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#ifndef BytecodeLivenessAnalysis_h
#define BytecodeLivenessAnalysis_h

#include "BytecodeBasicBlock.h"
#include <wtf/FastBitVector.h>
#include <wtf/HashMap.h>
#include <wtf/Vector.h>

namespace JSC {

class BytecodeKills;
class CodeBlock;
class FullBytecodeLiveness;

class BytecodeLivenessAnalysis {
    WTF_MAKE_FAST_ALLOCATED;
    WTF_MAKE_NONCOPYABLE(BytecodeLivenessAnalysis);
public:
    BytecodeLivenessAnalysis(CodeBlock*);
    
    bool operandIsLiveAtBytecodeOffset(int operand, unsigned bytecodeOffset);
    FastBitVector getLivenessInfoAtBytecodeOffset(unsigned bytecodeOffset);
    
    void computeFullLiveness(FullBytecodeLiveness& result);
    void computeKills(BytecodeKills& result);

private:
    void compute();
    void runLivenessFixpoint();
    void dumpResults();

    void getLivenessInfoAtBytecodeOffset(unsigned bytecodeOffset, FastBitVector&);

    CodeBlock* m_codeBlock;
    Vector<std::unique_ptr<BytecodeBasicBlock>> m_basicBlocks;
};

inline bool operandIsAlwaysLive(int operand);
inline bool operandThatIsNotAlwaysLiveIsLive(const FastBitVector& out, int operand);
inline bool operandIsLive(const FastBitVector& out, int operand);

} // namespace JSC

#endif // BytecodeLivenessAnalysis_h