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/*
* Copyright (C) 2011-2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 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
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#if ENABLE(DFG_JIT)
#include "DFGCommon.h"
#include "DFGDoubleFormatState.h"
#include "DFGFlushFormat.h"
#include "DFGFlushedAt.h"
#include "DFGNodeFlags.h"
#include "Operands.h"
#include "SpeculatedType.h"
#include "VirtualRegister.h"
#include <wtf/UnionFind.h>
namespace JSC { namespace DFG {
struct Node;
enum DoubleBallot { VoteValue, VoteDouble };
class VariableAccessData : public UnionFind<VariableAccessData> {
public:
VariableAccessData();
VariableAccessData(VirtualRegister local);
VirtualRegister local()
{
ASSERT(m_local == find()->m_local);
return m_local;
}
VirtualRegister& machineLocal()
{
ASSERT(find() == this);
return m_machineLocal;
}
bool mergeIsProfitableToUnbox(bool isProfitableToUnbox)
{
return checkAndSet(m_isProfitableToUnbox, m_isProfitableToUnbox || isProfitableToUnbox);
}
bool isProfitableToUnbox()
{
return m_isProfitableToUnbox;
}
bool mergeShouldNeverUnbox(bool shouldNeverUnbox);
// Returns true if it would be unsound to store the value in an unboxed fashion.
// If this returns false, it simply means that it is sound to unbox; it doesn't
// mean that we have actually done so.
bool shouldNeverUnbox()
{
return m_shouldNeverUnbox;
}
// Returns true if we should be unboxing the value provided that the predictions
// and double format vote say so. This may return false even if shouldNeverUnbox()
// returns false, since this incorporates heuristics of profitability.
bool shouldUnboxIfPossible()
{
return !shouldNeverUnbox() && isProfitableToUnbox();
}
bool mergeStructureCheckHoistingFailed(bool failed)
{
return checkAndSet(m_structureCheckHoistingFailed, m_structureCheckHoistingFailed || failed);
}
bool mergeCheckArrayHoistingFailed(bool failed)
{
return checkAndSet(m_checkArrayHoistingFailed, m_checkArrayHoistingFailed || failed);
}
bool structureCheckHoistingFailed()
{
return m_structureCheckHoistingFailed;
}
bool checkArrayHoistingFailed()
{
return m_checkArrayHoistingFailed;
}
bool mergeIsLoadedFrom(bool isLoadedFrom)
{
return checkAndSet(m_isLoadedFrom, m_isLoadedFrom || isLoadedFrom);
}
void setIsLoadedFrom(bool isLoadedFrom)
{
m_isLoadedFrom = isLoadedFrom;
}
bool isLoadedFrom()
{
return m_isLoadedFrom;
}
bool predict(SpeculatedType prediction);
SpeculatedType nonUnifiedPrediction()
{
return m_prediction;
}
SpeculatedType prediction()
{
return find()->m_prediction;
}
SpeculatedType argumentAwarePrediction()
{
return find()->m_argumentAwarePrediction;
}
bool mergeArgumentAwarePrediction(SpeculatedType prediction);
void clearVotes()
{
ASSERT(find() == this);
m_votes[0] = 0;
m_votes[1] = 0;
}
void vote(unsigned ballot, float weight = 1)
{
ASSERT(ballot < 2);
m_votes[ballot] += weight;
}
double voteRatio()
{
ASSERT(find() == this);
return static_cast<double>(m_votes[1]) / m_votes[0];
}
bool shouldUseDoubleFormatAccordingToVote();
DoubleFormatState doubleFormatState()
{
return find()->m_doubleFormatState;
}
bool shouldUseDoubleFormat()
{
ASSERT(isRoot());
bool doubleState = m_doubleFormatState == UsingDoubleFormat;
ASSERT(!(doubleState && shouldNeverUnbox()));
return doubleState && isProfitableToUnbox();
}
bool tallyVotesForShouldUseDoubleFormat();
bool mergeDoubleFormatState(DoubleFormatState);
bool makePredictionForDoubleFormat();
NodeFlags flags() const { return m_flags; }
bool mergeFlags(NodeFlags newFlags)
{
return checkAndSet(m_flags, m_flags | newFlags);
}
FlushFormat flushFormat();
bool couldRepresentInt52();
FlushedAt flushedAt()
{
return FlushedAt(flushFormat(), machineLocal());
}
private:
bool couldRepresentInt52Impl();
// This is slightly space-inefficient, since anything we're unified with
// will have the same operand and should have the same prediction. But
// putting them here simplifies the code, and we don't expect DFG space
// usage for variable access nodes do be significant.
VirtualRegister m_local;
VirtualRegister m_machineLocal;
SpeculatedType m_prediction;
SpeculatedType m_argumentAwarePrediction;
NodeFlags m_flags;
bool m_shouldNeverUnbox;
bool m_structureCheckHoistingFailed;
bool m_checkArrayHoistingFailed;
bool m_isProfitableToUnbox;
bool m_isLoadedFrom;
float m_votes[2]; // Used primarily for double voting but may be reused for other purposes.
DoubleFormatState m_doubleFormatState;
};
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)