JavaScriptCore-7600.1.4.11.8.tar.gz

[apple/javascriptcore.git] / ftl / FTLLoweredNodeValue.h

/*
 * Copyright (C) 2013 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
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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
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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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#ifndef FTLLoweredNodeValue_h
#define FTLLoweredNodeValue_h

#if ENABLE(FTL_JIT)

#include "DFGBasicBlock.h"
#include "FTLAbbreviatedTypes.h"

namespace JSC { namespace FTL {

// Represents the act of having lowered a DFG::Node to an LValue, and records the
// DFG::BasicBlock that did the lowering. The LValue is what we use most often, but
// we need to verify that we're in a block that is dominated by the one that did
// the lowering. We're guaranteed that for each DFG::Node, there will be one
// LoweredNodeValue that always dominates all uses of the DFG::Node; but there may
// be others that don't dominate and we're effectively doing opportunistic GVN on
// the lowering code.

class LoweredNodeValue {
public:
    LoweredNodeValue()
        : m_value(0)
        , m_block(0)
    {
    }
    
    LoweredNodeValue(LValue value, DFG::BasicBlock* block)
        : m_value(value)
        , m_block(block)
    {
        ASSERT(m_value);
        ASSERT(m_block);
    }
    
    bool isSet() const { return !!m_value; }
    bool operator!() const { return !isSet(); }
    
    LValue value() const { return m_value; }
    DFG::BasicBlock* block() const { return m_block; }
    
private:
    LValue m_value;
    DFG::BasicBlock* m_block;
};

} } // namespace JSC::FTL

#endif // ENABLE(FTL_JIT)

#endif // FTLLoweredNodeValue_h