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/*
* Copyright (C) 2012-2015 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.
*/
#include "config.h"
#include "DFGVariableEventStream.h"
#if ENABLE(DFG_JIT)
#include "CodeBlock.h"
#include "DFGJITCode.h"
#include "DFGValueSource.h"
#include "InlineCallFrame.h"
#include "JSCInlines.h"
#include <wtf/DataLog.h>
#include <wtf/HashMap.h>
namespace JSC { namespace DFG {
void VariableEventStream::logEvent(const VariableEvent& event)
{
dataLogF("seq#%u:", static_cast<unsigned>(size()));
event.dump(WTF::dataFile());
dataLogF(" ");
}
namespace {
struct MinifiedGenerationInfo {
bool filled; // true -> in gpr/fpr/pair, false -> spilled
bool alive;
VariableRepresentation u;
DataFormat format;
MinifiedGenerationInfo()
: filled(false)
, alive(false)
, format(DataFormatNone)
{
}
void update(const VariableEvent& event)
{
switch (event.kind()) {
case BirthToFill:
case Fill:
filled = true;
alive = true;
break;
case BirthToSpill:
case Spill:
filled = false;
alive = true;
break;
case Birth:
alive = true;
return;
case Death:
format = DataFormatNone;
alive = false;
return;
default:
return;
}
u = event.variableRepresentation();
format = event.dataFormat();
}
};
} // namespace
bool VariableEventStream::tryToSetConstantRecovery(ValueRecovery& recovery, MinifiedNode* node) const
{
if (!node)
return false;
if (node->hasConstant()) {
recovery = ValueRecovery::constant(node->constant());
return true;
}
if (node->op() == PhantomDirectArguments) {
recovery = ValueRecovery::directArgumentsThatWereNotCreated(node->id());
return true;
}
if (node->op() == PhantomClonedArguments) {
recovery = ValueRecovery::outOfBandArgumentsThatWereNotCreated(node->id());
return true;
}
return false;
}
void VariableEventStream::reconstruct(
CodeBlock* codeBlock, CodeOrigin codeOrigin, MinifiedGraph& graph,
unsigned index, Operands<ValueRecovery>& valueRecoveries) const
{
ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
CodeBlock* baselineCodeBlock = codeBlock->baselineVersion();
unsigned numVariables;
if (codeOrigin.inlineCallFrame)
numVariables = baselineCodeBlockForInlineCallFrame(codeOrigin.inlineCallFrame)->m_numCalleeLocals + VirtualRegister(codeOrigin.inlineCallFrame->stackOffset).toLocal() + 1;
else
numVariables = baselineCodeBlock->m_numCalleeLocals;
// Crazy special case: if we're at index == 0 then this must be an argument check
// failure, in which case all variables are already set up. The recoveries should
// reflect this.
if (!index) {
valueRecoveries = Operands<ValueRecovery>(codeBlock->numParameters(), numVariables);
for (size_t i = 0; i < valueRecoveries.size(); ++i) {
valueRecoveries[i] = ValueRecovery::displacedInJSStack(
VirtualRegister(valueRecoveries.operandForIndex(i)), DataFormatJS);
}
return;
}
// Step 1: Find the last checkpoint, and figure out the number of virtual registers as we go.
unsigned startIndex = index - 1;
while (at(startIndex).kind() != Reset)
startIndex--;
// Step 2: Create a mock-up of the DFG's state and execute the events.
Operands<ValueSource> operandSources(codeBlock->numParameters(), numVariables);
for (unsigned i = operandSources.size(); i--;)
operandSources[i] = ValueSource(SourceIsDead);
HashMap<MinifiedID, MinifiedGenerationInfo> generationInfos;
for (unsigned i = startIndex; i < index; ++i) {
const VariableEvent& event = at(i);
switch (event.kind()) {
case Reset:
// nothing to do.
break;
case BirthToFill:
case BirthToSpill:
case Birth: {
MinifiedGenerationInfo info;
info.update(event);
generationInfos.add(event.id(), info);
break;
}
case Fill:
case Spill:
case Death: {
HashMap<MinifiedID, MinifiedGenerationInfo>::iterator iter = generationInfos.find(event.id());
ASSERT(iter != generationInfos.end());
iter->value.update(event);
break;
}
case MovHintEvent:
if (operandSources.hasOperand(event.bytecodeRegister()))
operandSources.setOperand(event.bytecodeRegister(), ValueSource(event.id()));
break;
case SetLocalEvent:
if (operandSources.hasOperand(event.bytecodeRegister()))
operandSources.setOperand(event.bytecodeRegister(), ValueSource::forDataFormat(event.machineRegister(), event.dataFormat()));
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
// Step 3: Compute value recoveries!
valueRecoveries = Operands<ValueRecovery>(codeBlock->numParameters(), numVariables);
for (unsigned i = 0; i < operandSources.size(); ++i) {
ValueSource& source = operandSources[i];
if (source.isTriviallyRecoverable()) {
valueRecoveries[i] = source.valueRecovery();
continue;
}
ASSERT(source.kind() == HaveNode);
MinifiedNode* node = graph.at(source.id());
MinifiedGenerationInfo info = generationInfos.get(source.id());
if (!info.alive) {
valueRecoveries[i] = ValueRecovery::constant(jsUndefined());
continue;
}
if (tryToSetConstantRecovery(valueRecoveries[i], node))
continue;
ASSERT(info.format != DataFormatNone);
if (info.filled) {
if (info.format == DataFormatDouble) {
valueRecoveries[i] = ValueRecovery::inFPR(info.u.fpr, DataFormatDouble);
continue;
}
#if USE(JSVALUE32_64)
if (info.format & DataFormatJS) {
valueRecoveries[i] = ValueRecovery::inPair(info.u.pair.tagGPR, info.u.pair.payloadGPR);
continue;
}
#endif
valueRecoveries[i] = ValueRecovery::inGPR(info.u.gpr, info.format);
continue;
}
valueRecoveries[i] =
ValueRecovery::displacedInJSStack(static_cast<VirtualRegister>(info.u.virtualReg), info.format);
}
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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